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Three-Dimensional Ultrasound-Guided Placement of Ventricular Catheters
Abstract
Many studies demonstrate that the accuracy of freehand catheter placement for CSF drainage is suboptimal. The aim of placement should be a single pass with a free-floating catheter tip in the intended position. We aimed to achieve an accurate and user friendly system for 3D ultrasound navigated catheter placement through a regular burr hole.
A new phased-array ultrasound burr-hole probe (4-10 MHz, 8x9 mm footprint) was especially developed and optimized for navigated 3D ultrasound with the Sonowand Invite system. A catheter holder for optical tracking was also developed. Head immobilization was done with a vacuum cushion. With the described set-up 4 patients were operated. We present radiological data and describe the method in detail.
Ultrasound image quality and visualization of the ventricles was good in all cases. We achieved optimal placement of the catheter in a single pass in all patients. One of the trajectories was slightly more medial on postoperative CT than anticipated from the neuronavigation system. None of the patients experienced any adverse event related to the procedure.
3D ultrasound with the described set-up is a promising technique for accurate, fast and user-friendly navigated placement of catheters for CSF diversion.
... In addition to US-guided surgical navigation and radiotherapy, US-guided catheterization has also attracted the attention of many researchers. Jakola et al. [180] reported a method to guide the placement of ventricular catheters using 3D US navigation system. The US-based navigation system (Sonowand Invite, Sonowand AS, Trondheim, Norway) consisted of an US probe integrated with an optical tracking system. ...
... Kobayashi et al. [182] In addition to US-guided surgical navigation and radiotherapy, US-guided catheterization has also attracted the attention of many researchers. Jakola et al. [180] reported a method to guide the placement of ventricular catheters using 3D US navigation system. The US-based navigation system (Sonowand Invite, Sonowand AS, Trondheim, Norway) consisted of an US probe integrated with an optical tracking system. ...
With the rapid advancement of tracking technologies, the applications of tracking systems in ultrasound imaging have expanded across a wide range of fields. In this review article, we discuss the basic tracking principles, system components, performance analyses, as well as the main sources of error for popular tracking technologies that are utilized in ultrasound imaging. In light of the growing demand for object tracking, this article explores both the potential and challenges associated with different tracking technologies applied to various ultrasound imaging applications, including freehand 3D ultrasound imaging, ultrasound image fusion, ultrasound-guided intervention and treatment. Recent development in tracking technology has led to increased accuracy and intuitiveness of ultrasound imaging and navigation with less reliance on operator skills, thereby benefiting the medical diagnosis and treatment. Although commercially available tracking systems are capable of achieving sub-millimeter resolution for positional tracking and sub-degree resolution for orientational tracking, such systems are subject to a number of disadvantages, including high costs and time-consuming calibration procedures. While some emerging tracking technologies are still in the research stage, their potentials have been demonstrated in terms of the compactness, light weight, and easy integration with existing standard or portable ultrasound machines.
... The misplacement rates reported in literature are high, probably due to the use of EVD also in patients affected by midline shift or slit ventricles and in procedures performed by non-neurosurgeons in remote areas with logistic difficulties. Numerous studies have already been published about the reduction of complication after EVD, which is currently a freehand procedure, performed only according to anatomical landmarks that help to introduce the catheter perpendicularly to the burr hole; the perpendicularity is a critical element for the correct positioning of the catheter (Gil et al., 2002;Shimizu et al., 2004;Lee et al., 2008Lee et al., , 2020Mahan et al., 2013;Patil et al., 2013;Jakola et al., 2014;Siesjö, 2014;Shtaya et al., 2018;Thomale et al., 2018;Wilson et al., 2018;Fuller et al., 2020;Park et al., 2020;Sun et al., 2020;Amoo et al., 2021;Cabrilo et al., 2021;Pishjoo et al., 2021). ...
... The device can be used on its own but is neuronavigation-ready. Navigation is handy in the case of midline shifts, in which the normal anatomy is altered and it is not possible to use the typical anatomical landmarks and in the case of "slit ventricles, " in which the target is challenging to reach (Gil et al., 2002;Mahan et al., 2013;Jakola et al., 2014;Thomale et al., 2018). If used on a patient with no midline shift, the device is as accurate as navigation, which is then unnecessary, thus saving costs (Chai et al., 2013). ...
Background
External ventricular drain (EVD) placement is mandatory for several pathologies. The misplacement rate of the EVD varies widely in literature, ranging from 12.3 to 60%. The purpose of this simulation study is to provide preliminary data about the possibility of increasing the safety of one of the most common life-saving procedures in neurosurgery by testing a new device for EVD placement.
Methods
We used a novel guide for positioning the ventricular catheter (patent RM2014A000376). The trajectory was assessed using 25 anonymized head CT scans. The data sets were used to conduct three-dimensional computer-based and combined navigation and augmented reality-based simulations using plaster models. The data set inclusion criteria were volumetric head CT scan, without midline shift, of patients older than 18. Evans’ index was used to quantify the ventricle’s size. We excluded patients with slit ventricles, midline shift, skull fractures, or complex skull malformations. The proximal end of the device was tested on the cadaver.
Results
The cadaveric tests proved that a surgeon could use the device without any external help. The multimodal simulation showed Kakarla grade 1 in all cases but one (grade 2) on both sides, after right and left EVD placement. The mean Evans’ index was 0.28. The geometric principles that explain the device’s efficacy can be summarized by studying the properties of circumference and chord. The contact occurs, for each section considered, at the extreme points of the chord. Its axis, perpendicular to the plane tangent to the spherical surface at the entry point, corresponds to the direction of entry of the catheter guided by the instrument.
Conclusion
According to our multimodal simulation on cadavers, 3D computer-based simulation, 3D plaster modeling, 3D neuronavigation, and augmented reality, the device promises to offer safer and effective EVD placement. Further validation in future clinical studies is recommended.
... Intracranial hemorrhage, CSF infections, and neurological deficits are additional complications that may be caused by EVD misplacement with either multiple puncture attempts or need of revision [13,18]. To overcome the problems of incorrectly placed ventricular catheters, the usage of a variety of technical aids such as guiding protractors [10,32], fluoroscopy or computer tomography (CT) [8,9], frameless stereotaxy [14,24], ultrasonography [11], neuroendoscopy [29], electromagnetic neuronavigation [17], robotics [16,23], and smartphoneassisted guidance has been reported [6,7,19,25]. To date, all these techniques are disadvantageous due to higher costs, longer procedure times, and more technical efforts including the necessity of taking the patient to the operating room, making bedside EVD implantation impossible. ...
Purpose
External ventricular drain (EVD) implantation is one of the fundamental procedures of emergency neurosurgery usually performed freehand at bedside or in the operating room using anatomical landmarks. However, this technique is frequently associated with malpositioning leading to complications or dysfunction. Here, we describe a novel navigated bedside EVD insertion technique, which is evaluated in a clinical case series with the aim of safety, accuracy, and efficiency in neurosurgical emergency settings.
Methods
From 2021 to 2022, a mobile health–assisted navigation instrument (Thomale Guide, Christoph Miethke, Potsdam, Germany) was used alongside a battery-powered single-use drill (Phasor Health, Houston, USA) for bedside EVD placement in representative neurosurgical pathologies in emergency situations requiring ventricular cerebrospinal fluid (CSF) relief and intracranial pressure (ICP) monitoring.
Results
In all 12 patients (8 female and 4 male), navigated bedside EVDs were placed around the foramen of Monro at the first ventriculostomy attempt. The most frequent indication was aneurysmal subarachnoid hemorrhage. Mean operating time was 25.8 ± 15.0 min. None of the EVDs had to be revised due to malpositioning or dysfunction. Two EVDs were converted into a ventriculoperitoneal shunt. Drainage volume was 41.3 ± 37.1 ml per day in mean. Mean length of stay of an EVD was 6.25 ± 2.8 days. Complications included one postoperative subdural hematoma and cerebrospinal fluid infection, respectively.
Conclusion
Combining a mobile health–assisted navigation instrument with a battery-powered drill and an appropriate ventricular catheter may enable and enhance safety, accuracy, and efficiency in bedside EVD implantation in various pathologies of emergency neurosurgery without adding relevant efforts.
... 16 However, in addition to equipment cost and availability, its widespread adoption is limited by the need for larger burr holes, often drilled in the OR, as the ultrasound probe needs to be in the same plane as the ventricular catheter. 17 Currently, ultrasound guidance is used in less than 1% of EVD placements. 18 Although another orthogonally based device, the Ghajar guide, has similarly proven to improve catheter accuracy, this device has not seen widespread adoption and has significant design limitations. ...
OBJECTIVE
The authors designed a low-profile device for reliable ventricular access and prospectively studied its safety, efficacy, and accuracy at a large academic center.
METHODS
A novel device for ventricular entry, the Device for Intraventricular Entry (DIVE) guide, was designed and created by the first and senior authors. Fifty patients undergoing external ventricular drainage (EVD) or shunt placement were prospectively enrolled for DIVE-assisted catheter placement at a single academic center. The primary outcome was the catheter tip location on postprocedural CT. Secondary outcomes included number of catheter passes, clinically significant hemorrhages, and procedure-related infections.
RESULTS
Fifty patients were enrolled. Indications included subarachnoid hemorrhage, intraventricular hemorrhage, traumatic brain injury, hydrocephalus, pseudotumor, and postsurgical wound drainage. In total, 76% (38/50) of patients underwent right-sided placement and 24% (12/50) underwent left-sided placement. All 100% (50/50) of patients had successful cannulation with an average of 1.06 passes. Postprocedural head CT confirmed ipsilateral frontal horn or third ventricle placement (Kakarla grade 1) in 92% (46/50) of patients and placement in the contralateral lateral ventricle in 8% (4/50) (Kakarla grade 2). There were no clinically significant track hemorrhages or procedural infections.
CONCLUSIONS
This single-center prospective study investigated the safety and efficacy of DIVE-assisted ventricular access. In total, 100% of procedures had successful ventricular cannulation, with 92% achieving Kakarla grade 1, with an average of 1.06 passes without any clinical complications.
... Therefore, multiple studies have utilized surgical navigation in EVD surgery for higher operation accuracy and lower surgical risks [10]- [12], and have proven their effectiveness. Traditional surgical guidance utilizes intraoperative CT scanning [13], optical tracking systems [14], and electromagnetic tracking systems [15] to provide spatial information during operation, and typically display guidance information on a two-dimensional screen away from the surgical area. Such approaches result in complex setups, hand-eye coordination deficits, and distraction, preventing them from being widely adopted in daily practice [7], [16]. ...
Augmented Reality (AR) has been used to facilitate surgical guidance during External Ventricular Drain (EVD) surgery, reducing the risks of misplacement in manual operations. During this procedure, the pivotal challenge is the accurate estimation of spatial relationship between pre-operative images and actual patient anatomy in AR environment. In this research, we propose a novel framework utilizing Time of Flight (ToF) depth sensors integrated in commercially available AR Head Mounted Devices (HMD) for precise EVD surgical guidance. As previous studies have proven depth errors for ToF sensors, we first conducted a comprehensive assessment for the properties of this error on AR-HMDs. Subsequently, a depth error model and patient-specific model parameter identification method, is introduced for accurate surface information. After that, a tracking procedure combining retro-reflective markers and point clouds is proposed for accurate head tracking, where head surface is reconstructed using ToF sensor data for spatial registration, avoiding fixing tracking targets rigidly on the patient's cranium. Firstly, ToF sensor depth value error was revealed on human skin, indicating the significance of depth correction. Our results showed that the ToF sensor depth error was reduced by over using proposed depth correction method on head phantoms in different materials. Meanwhile, the head surface reconstructed with corrected depth data achieved sub-millimeter accuracy. Experiment on a sheep head revealed reconstruction error. Furthermore, a user study was conducted for the performance of proposed framework in simulated EVD surgery, where 5 surgeons performed 9 k-wire injections on a head phantom with virtual guidance. Results of this study revealed translational accuracy and orientational accuracy.
... [44] 2014 4 4,5 SLF III, SLF II IFOF 36 Jakola ve ark. [45] 2014 3 1 SLF II, FAT 37 Nasi ve ark. [46] 2017 2-3 9 IFOF, SLF II 38 Aref ve ark. ...
... Whitehead et al. reported accurate real-time US-guided placement of ventricular catheters for CSF shunts in children, but this also required burr hole enlargement [34]. Jakola et al. describe the use of a phased-array ultrasound burr hole probe developed for EVD placement [35]. In a small case series, four patients underwent ventriculostomy using this technology with optimal placement achieved in a single pass in all patients with no reported adverse events. ...
External ventricular drainage is a common and invaluable neurosurgical procedure and is one of the first procedures learned and performed independently by neurosurgical residents. As accuracy and precision are paramount to EVD placement, attention to technique is paid early in a resident’s training. With the advancement of virtual technology, it has become increasingly possible to move away from traditional training situations and human error, and towards automated assistance and superior cyber learning environments. Although there is significant room for improvement, there are promising results with computerized placement guides and virtually augmented practice. Here, we provide a review of the updates on EVD placement techniques, technology and training, all of which serve to improve the precision, accuracy and efficiency of EVD placement.
... EVD is a very common procedure, but freehand EVD insertion can be associated with high chances of inaccurate EVD placement [17]. Navigation-guided and three-dimensional (3D) ultrasound-navigated placement of EVD in ICU setting has been reported to be feasible and associated with better chances of accurate EVD placement [26,34,36]. Moreover, there is risk of CSF infection and intracranial hemorrhage following EVD insertion [12,13,28,37]. ...
External ventricular drain (EVD) is one of the most commonly performed neurosurgical procedures. EVD can be associated with high rates of complications like misplacement, iatrogenic hemorrhage, and CSF infection. Several modifications have been proposed in the EVD insertion techniques to decrease the risk of these complications. Bolt-connected EVD, one of these modifications which involves insertion of a bolt in the burr hole, has been proposed to have better chances of optimal placement of EVD tip, lesser risk of CSF infection, and accidental pullout. A comprehensive search of different databases was performed to retrieve studies comparing the bolt-connected EVD with tunneled EVD and meta-analysis was done. Seven studies met inclusion criteria and were included in the meta-analysis. Our analysis revealed that bolt-connected EVD is associated with significantly better chances of optimal placement than traditional tunneled EVD (MH OR—1.65, 95% CI 1.14 to 2.40, p = 0.008). We also observed that bolt-connected EVD is associated with significantly decreased risk of CSF infection (MH OR—0.60, 95% CI 0.39 to 0.94, p = 0.026), EVD malfunction (MH OR—0.31, 95% CI 0.16 to 0.58, p = 0.0003), and accidental disconnection (MH OR—0.09, 95% CI 0.03 to 0.26, p < 0.0001) as compared to traditional tunneled EVD. The difference between the two techniques was not statistically significant for complications, multiple punctures done for insertion of EVD, iatrogenic intracranial, and need of reoperation. Bolt-connected external ventricular drain is associated with significantly more chances of optimal placement and lesser chances of accidental discontinuation and CSF infection than tunneled EVD. There was no statistically significant difference noted between the two techniques for multiple punctures done for insertion of EVD, iatrogenic intracranial hemorrhage and need of reoperation. However, most of the included studies were retrospective. Thus, the results from the meta-analysis should be interpreted with caution as further prospective high-quality studies are needed.
... While some of these figures seem deceptively small, they translate into a very high morbidity given that nearly 25,000 procedures are performed annually in the US alone 15 . Image-guided placement of EVD catheters with and without devices such as the Ghajar guide have been previously trialed as an alternative to the freehand technique [12][13][14]16,17 . Although these have improved the accuracy of catheter placement, they continue to experience significant limitations. ...
External ventricular drainage (EVD) is an emergency neurosurgical procedure to decrease intracranial pressure through a catheter mediated drainage of cerebrospinal fluid. Most EVD catheters are placed using free hands without direct visualization of the target and catheter trajectory, leading to a high rate of complications- hemorrhage, brain injury and suboptimal catheter placement. Use of stereotactic systems can prevent these complications. However, they have found limited application for this procedure due to their long set-up time and expensive hardware. Therefore, we have developed and pre-clinically validated a novel 3D printed stereotactic system for rapid and accurate implantation of EVD catheters. Its mechanical and imaging accuracies were found to be at par with clinical stereotactic systems. Preclinical trial in human cadaver specimens revealed improved targeting accuracy achieved within an acceptable time frame compared to the free hand technique. CT angiography emulated using cadaver specimen with radio-opaque vascular contrast showed vessel free catheter trajectory. This could potentially translate to reduced hemorrhage rate. Thus, our 3D printed stereotactic system offers the potential to improve the accuracy and safety of EVD catheter placement for patients without significantly increasing the procedure time.
... Ventricular catheter placement to normal-sized or slit-like ventricles is rather challenging in comparison to hydrocephalic patients. Intraoperative ultrasound (iUS) has emerged as an alternative guiding technique to traditional stereotaxy, frameless or electromagnetic neuronavigation systems, and neuroendoscopy [1][2][3][4]6]. Precise placement of the distal catheter to the frontal horn is required for avoiding dysfunctions [7]. In our department, we prefer iUS guided catheter insertion for the advantages such as decreased operative time, increased firstpass rate, and real-time visualization of the catheter's final position inside the ventricle. ...
Background
Intraventricular chemotherapy via Ommaya reservoir is an important part of the treatment in patients with malignant central nervous system tumors. In these patients, catheter placement can be challenging due to the normal-sized ventricles.Method
Intraoperative ultrasound guidance was used for Ommaya reservoir placement in a 56-year-old patient with multiple intracranial and leptomeningeal metastases who had cavum septum pellucidum et vergae malformation. The catheter was successfully placed into the frontal horn of the lateral ventricle outside the cavum.Conclusion
Intraoperative ultrasound is a suitable image guidance system in patients with slit-like or normal-sized ventricles. It can also be used in patients with ventricular malformations.
... Furthermore, hardware misplacement accounts for a significant portion of surgical complications. Many have examined ways to optimise drain placement and perhaps routine utilisation of intraoperative ultrasound and/or neuronavigation could reduce the number of IIb complications [7,11]. ...
Background
CSF diversion with shunt placement is frequently associated with need for later revisions as well as surgical complications. We sought to review revision and complication rates following ventriculoperitoneal, ventriculoatrial and cystoperitoneal shunt placement in adult patients, and to identify potential risk factors for revision surgery and postoperative complications.
Method
Included patients were adults (≥ 18 years) who underwent primary shunt insertion at St. Olavs Hospital in Trondheim, Norway, from 2008 through 2017. The electronic medical records and diagnostic imaging from all hospitals in our catchment area were retrospectively reviewed. Follow-up ranged from 1 to 11 years. Complications were graded according to the Landriel Ibañez classification system.
Results
Of the 227 patients included, 47 patients (20.7%) required revision surgery during the follow-up. In total, 90 revision surgeries were performed during follow-up. The most common cause for the first revision was infection (5.7%) and for all revisions proximal occlusion (30.0%). A total of 103 patients (45.4%) experienced ≥ 1 complication(s). Mild to moderate complications (grade I and II) were detected in 35.0% of all procedures. Severe or fatal complications (grade III and IV) were observed in 8.2% of all procedures. Urinary tract infections and pneumonia were common postoperatively (13.9% and 7.3%, respectively), and the most common IIb complication was shunt misplacement (proximally or distally). Two out of fourteen deaths within 30 days were directly associated with surgery. We did not find that aetiology/indication, age or gender influenced the occurrence of revision surgery or a grade III or IV complication.
Conclusions
Shunt surgery continues to be a challenge both in terms of revision rates and procedure-related complications. However, the prediction of patients at risk remains difficult. A multidimensional focus is probably needed to reduce risks.
... Ultrasound imaging may be another option as it is relatively inexpensive and provides real-time feedback. [27] Jakola et al. [28] studied the effectiveness of three-dimensional ultrasound placement of ventricular catheters in four patients. Single-pass satisfactory placement of the catheter was achieved in all the patients. ...
Introduction:
External ventricular drain (EVD) placement is the gold standard for managing acute hydrocephalus. Freehand EVD, using surface anatomical landmarks, is performed for ventricular cannulation due to its simplicity and efficiency. This study evaluates accuracy and reason(s) for misplacements as few studies have analyzed the accuracy of freehand EVD insertion.
Patients and methods:
Preoperative and postoperative computed tomography scans of patients who underwent EVD insertion in 2014 were retrospectively reviewed. Diagnosis, Evans ratio, midline shift, position of burr hole, length of the catheter, and procedural complications were tabulated. The procedures were classified as satisfactory (catheter tip in the frontal horn ipsilateral lateral ventricle) and unsatisfactory. Unsatisfactory cases were further analyzed in relation to position of burr hole from midline and length of the catheter.
Results:
Seventy-seven EVD placements in seventy patients were evaluated. The mean age of the patients was 57.5 years. About 83.1% were satisfactory placements and 11.7% were unsatisfactory in the contralateral ventricle, corpus callosum, and interhemispheric fissure. Nearly 5.2% were in extraventricular locations. Almost 2.6% EVD placements were complicated by hemorrhage and 1 catheter was reinserted. Suboptimal placements were significantly associated with longer intracranial catheter length. The mean length was 66.54 ± 10.1 mm in unsatisfactory placements compared to 58.32 ± 4.85 mm in satisfactory placements. Between the two groups, no significant difference was observed in Evans ratio, midline shift, surgeon's experience, distance of burr hole from midline, and coronal suture.
Conclusion:
Freehand EVD insertion is safe and accurate. In small number of cases, unsatisfactory placement is related to longer catheter length.
... Despite the use of anatomical landmarks to determine Kocher's point and our knowledge of estimating the trajectory toward the ipsilateral frontal horn, accurate EVD placement can be challenging. Numerous studies have assessed ways of optimising drain placement [12,14,16,19]. Thus, developing and improving surgical methods to improve accuracy and minimise complications rates continue to be of great interest. ...
Background
An external ventricular drain (EVD) is typically indicated in the presence of hydrocephalus and increased intracranial pressure (ICP). Procedural challenges have prompted the development of different methods to improve accuracy, safety, and logistics.ObjectivesEVD placement and complications rates were compared using two surgical techniques; the standard method (using a 14-mm trephine burrhole with the EVD tunnelated through the skin) was compared to a less invasive method (EVD placed through a 2.7–3.3-mm twist drill burrhole and fixed to the bone with a bolt system).Methods
Retrospective observational study in a single-centre setting between 2008 and 2018. EVD placement was assessed using the Kakarla scoring system. We registered postoperative complications, surgery duration and number of attempts to place the EVD.ResultsTwo hundred seventy-two patients received an EVD (61 bolt EVDs, 211 standard EVDs) in the study period. Significant differences between the bolt system and the standard method were observed in terms of revision surgeries (8.2% vs. 21.5%, p = 0.020), surgery duration (mean 16.5 vs. 28.8 min, 95% CI 7.64, 16.8, p < 0.001) and number of attempts to successfully place the first EVD (mean 1.72 ± 1.2 vs. 1.32 ± 0.8, p = 0.017). There were no differences in accuracy of placement or complication rates.Conclusions
The two methods show similar accuracy and postoperative complication rates. Observed differences in both need for revisions and surgery duration favoured the bolt group. Slightly, more attempts were needed to place the initial EVD in the bolt group, perhaps reflecting lower flexibility for angle correction with a twist drill approach.
... Recent studies indicate that the rapidly developing technique of real-time 3D US can accurately locate the instruments and show the 3D relationship between the instruments and the organs. This technique has been successfully used to guide operations such as ablation of hepatic carcinoma, cardiac interventional operation and neurosurgery operation [8][9][10][11]. ...
Objectives
To evaluate the effect of real‐time 3‐dimensional ultrasound (real‐time 3DUS) in guiding percutaneous nephrostomy (PCN).
Materials and Methods
A hydronephrosis model was devised by obstruction of ureters of 16 beagles divided equally into groups 1 and 2. In group 1, the PCN was guided using real‐time three‐dimensional ultrasound whereas the PCN was guided using two‐dimensional ultrasound (2DUS) in group 2. The clearance of needle tract, puncture time, and puncture times were recorded for the two groups.
Results
In group 1, the clearance of needle tract, puncture time, and puncture times resulted in a score of 3, 7.3±3.1s and one time, respectively. In group 2, the same parameters resulted in a score of 1.4±0.5, 21.4±5.8s and 2.1±0.6 times, respectively. The clearance of needle tract in group 1 was superior to that in group 2 while puncture time, and puncture times both decreased in group 1 compared with those in group 2.
Conclusions
Real‐time 3DUS‐guided PCN is superior to 2DUS‐guided PCN in visualization of needle tract and targeted PCS, leading to quick puncture. Real‐time 3DUS‐guided puncture of the kidney holds great promise for clinical implementation of PCN.
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... In these events, iUS allows direct visualization of the ventricles, increasing the precision and safety of the procedures. We used the trajectory based on 3D-navigated iUS in two cases (using the technique described by Jakola et al. [7]) and on 2D real-time iUS guidance in the two remaining cases. We obtained correct catheter placement with both methods. ...
Background:
The use of intraoperative ultrasound (iUS) has increased in the last 15 years becoming a standard tool in many neurosurgical centers. Our aim was to assess the utility of routine use of iUS during various types of intracranial surgery. We reviewed our series to assess ultrasound visibility of different pathologies and iUS applications during the course of surgery.
Materials and methods:
This is a retrospective review of 162 patients who underwent intracranial surgery with assistance of the iUS guidance system (SonoWand). Pathologic categories were neoplastic (135), vascular (20), infectious (2), and CSF related (5). Ultrasound visibility was assessed using the Mair classification, a four-tiered grading system that considers the echogenicity of the lesion and its border visibility (from 0 to 3; grade 0, pathology not visible; grade 3, visible with clear border with normal tissue). iUS applications included lesion localization, approach planning to deep-seated lesions, and lesion removal.
Results:
All pathologies were visible on iUS except one aneurysm. On average, extra-axial tumors were identified more easily and had clearer limits compared to intra-axial tumors (extra-axial 17% grade 2, 83% grade 3; intra-axial 5.5% grade 1, 46.5% grade 2, 48% grade 3). iUS provided precise and safe transcortical trajectories to deep-seated lesions (71 patients; tumors, hemangiomas, ICHs); iUS was judged to be less useful to approach skull base tumors and aneurysms. iUS was used to judge extent of resection in 152 cases; surgical artifacts reduced sonographic visibility in 25 cases: extent of resection was correctly checked in 127 patients (53 gliomas, 15 metastases, 39 meningiomas, 4 schwannomas, 4 sellar region tumors, 6 hemangiomas, 3 AVMs, 2 abscesses).
Conclusions:
iUS was highly sensitive in detecting all types of pathology, was safe and precise in planning trajectories to intraparenchymal lesions (including minimally mini-invasive approaches), and was accurate in checking extent of resection in more than 80% of cases. iUS is a versatile and feasible tool; it could improve safety and its use may be considered in routine intracranial surgery.
... We have demonstrated excellent results using an optical tracking frameless stereotaxy approach, which has become standard technology available across modern neuronavigation systems. However, there are many alternative methods for improving ventricular targeting that have been proposed by different groups, including frame-based targeting [2,8], fluoroscopy-assisted [9], electromagnetic tracking [14], and ultrasound-guided [6] implantations. On our review, studies comparing image-guided methods have demonstrated statistical equivalence: Morgenstern et al. compared fluoroscopy and frameless stereotaxy [9]; Kennedy and colleagues compared frame-based and frameless stereotaxy [8]. ...
Background
Ayub Ommaya proposed a surgical technique for subcutaneous reservoir and pump placement in 1963 to allow access to intraventricular cerebrospinal fluid (CSF). Currently, the most common indication for Ommaya reservoir insertion (ORI) in adults is for patients with hematologic or leptomeningeal disorders requiring repeated injection of chemotherapy into the CSF space. Historically, the intraventricular catheter has been inserted blindly based on anatomical landmarks. The purpose of this study was to examine short-term complication rates with ORI with image guidance (IG) and without image guidance (non-IG). Methods
We retrospectively evaluated all operative cases of ORI from 2000 to 2014 by the senior author. Patient demographic data, surgical outcomes, and peri-operative complications were collected. Accurate placement and early (30-day) morbidity or mortality were considered primary outcomes. ResultsFifty-five consecutive patients underwent ORI by the senior author over the study period (43.5 ± 16.6 years; 40.0% female). Indications for placement included acute lymphoblastic leukemia, diffuse large B-cell lymphoma, and leptomeningeal carcinomatosis. There were seven (12.7%) total complications: three (37.5%) with no-IG versus four (8.5%) with IG. Catheter malpositions were significantly higher in the non-IG group at 37.5% compared to 2.1%. Catheters were also more likely to require multiple passes with non-IG at 25% compare to 0% with IG. There were no early infections in either group. Conclusions
We demonstrate improved accuracy and decreased complications using an image-guided approach compared with a traditional approach. Our results support routine use of intra-operative image guidance for proximal catheter insertion in elective ORI for intraventricular chemotherapy.
... Subtraction of a small volume of CSF may reduce markedly the intracranial pressure. External ventricular drain can be inserted using neuronavigation [99]. ...
The latest French Guidelines for the management in the first 24hours of patients with severe traumatic brain injury (TBI) were published in 1998. Due to recent changes (intracerebral monitoring, cerebral perfusion pressure management, treatment of raised intracranial pressure), an update was required. Our objective has been to specify the significant developments since 1998. These guidelines were conducted by a group of experts for the French Society of Anesthesia and Intensive Care Medicine (Société Francaise d'Anesthésie Réanimation (SFAR)) in partnership with the Association de Neuro-Anesthésie-Réanimation de Langue Française (ANARLF), the Société Française de Neurochirurgie (SFN), the Groupe Francophone de Réanimation et d'Urgences Pédiatriques (GFRUP) and the Association des Anesthésistes-Réanimateurs Pédiatriques d'Expression Française (ADARPEF). The method used to elaborate these guidelines was the GRADE® method. After two Delphi rounds, 32 recommendations were formally developed by the experts focusing on the evaluation the initial severity of traumatic brain injury, the modalities of prehospital management, imaging strategies, indications for neurosurgical interventions, sedation and analgesia, indications and modalities of cerebral monitoring, medical management of raised intracranial pressure, management of multiple trauma with severe traumatic brain injury, detection and prevention of post-traumatic epilepsia, biological homeostasis (osmolarity, glycaemia, adrenal axis) and paediatric specificities.
... The versatility of the AR paradigm has allowed for its integration into a variety of US-guided interventions. For example, in neurosurgical navigation, several AR US image guidance (AR-UIG) systems such as the SonoWand Invite system (Trondheim, Norway) [15,33] are already available on the market as clinically-approved devices. In cardiac electrophysiology, CARTO (Biosense Webster Ltd, Israel) is a navigation system used for the treatment of patients with cardiac arrhythmia in which intra-cardiac US images, information from multiple sensors, and the position of the RF ablation catheter are integrated with a virtual environment. ...
Purpose:
Real-time ultrasound has become a crucial aspect of several image-guided interventions. One of the main constraints of such an approach is the difficulty in interpretability of the limited field of view of the image, a problem that has recently been addressed using mixed reality, such as augmented reality and augmented virtuality. The growing popularity and maturity of mixed reality has led to a series of informal guidelines to direct development of new systems and to facilitate regulatory approval. However, the goals of mixed reality image guidance systems and the guidelines for their development have not been thoroughly discussed. The purpose of this paper is to identify and critically examine development guidelines in the context of a mixed reality ultrasound guidance system through a case study.
Methods:
A mixed reality ultrasound guidance system tailored to central line insertions was developed in close collaboration with an expert user. This system outperformed ultrasound-only guidance in a novice user study and has obtained clearance for clinical use in humans. A phantom study with 25 experienced physicians was carried out to compare the performance of the mixed reality ultrasound system against conventional ultrasound-only guidance. Despite the previous promising results, there was no statistically significant difference between the two systems.
Results:
Guidelines for developing mixed reality image guidance systems cannot be applied indiscriminately. Each design decision, no matter how well justified, should be the subject of scientific and technical investigation. Iterative and small-scale evaluation can readily unearth issues and previously unknown or implicit system requirements.
Conclusions:
We recommend a wary eye in development of mixed reality ultrasound image guidance systems emphasizing small-scale iterative evaluation alongside system development. Ultimately, we recommend that the image-guided intervention community furthers and deepens this discussion into best practices in developing image-guided interventions.
... very high success rates of 88%-100% achieved with sonography, neuronavigation, or CT guidance. 11,18,20,25,28,29,48,51 Our cohort consisted exclusively of adult patients and we would be cautious about extending our results to children, because we conducted no tests on children's skulls. ...
... La soustraction d'un faible volume dans un cerveau à compliance abaissée réduit significativement la pression intracrânienne. Actuellement, ces cathéters peuvent être posés sous neuronavigation [98]. Une embarrure fermée compressive (épaisseur > 5 mm, effet de masse avec déplacement de la ligne médiane > 5 mm) doit être opérée. ...
... very high success rates of 88%-100% achieved with sonography, neuronavigation, or CT guidance. 11,18,20,25,28,29,48,51 Our cohort consisted exclusively of adult patients and we would be cautious about extending our results to children, because we conducted no tests on children's skulls. ...
OBJECTIVE
Frontal ventriculostomy is one of the most frequent and standardized procedures in neurosurgery. However, many first and subsequent punctures miss the target, and suboptimal placement or misplacement of the catheter is common. The authors therefore reexamined the landmarks and rules to determine the entry point and trajectory with the best hit rate (HtR).
METHODS
The authors randomly selected CT scans from their institution’s DICOM pool that had been obtained in 50 patients with normal ventricular and skull anatomy and without ventricular puncture. Using a 5 × 5–cm frontal grid with 25 entry points referenced to the bregma, the authors examined trajectories 1) perpendicular to the skull, 2) toward classic facial landmarks in the coronal and sagittal planes, and 3) toward an idealized target in the middle of the ipsilateral anterior horn (ILAH). Three-dimensional virtual reality ventriculostomies were simulated for these entry points; trajectories and the HtRs were recorded, resulting in an investigation of 8000 different virtual procedures.
RESULTS
The best HtR for the ILAH was 86% for an ideal trajectory, 84% for a landmark trajectory, and 83% for a 90° trajectory, but only at specific entry points. The highest HtRs were found for entry points 3 or 4 cm lateral to the midline, but only in combination with a trajectory toward the contralateral canthus; and 1 or 2 cm lateral to the midline, but only paired with a trajectory toward the nasion. The same “pairing” exists for entry points and trajectories in the sagittal plane. For perpendicular (90°) trajectories, the best entry points were at 3–5 cm lateral to the midline and 3 cm anterior to the bregma, or 4 cm lateral to the midline and 2 cm anterior to the bregma.
CONCLUSIONS
Only a few entry points offer a chance of a greater than 80% rate of hitting the ILAH, and then only in combination with a specific trajectory. This “pairing” between entry point and trajectory was found both for landmark targeting and for perpendicular trajectories, with very limited variability. Surprisingly, the ipsilateral medial canthus, a commonly reported landmark, had low HtRs, and should not be recommended as a trajectory target.
... La soustraction d'un faible volume dans un cerveau à compliance abaissée réduit significativement la pression intracrânienne. Actuellement, ces cathéters peuvent être posés sous neuronavigation [98]. Une embarrure fermée compressive (épaisseur > 5 mm, effet de masse avec déplacement de la ligne médiane > 5 mm) doit être opérée. ...
... Whitehead et al., on the other hand showed an accurate placement of CSF shunt ventricular catheters in a pediatric population using real-time ultrasound guidance [29]. Also Jakola et al., just recently presented their results with a similar technique using a three-dimensional ultrasound-guided placement of ventricular catheters [11]. The authors report an optimal placement of the catheter in a single pass in all four patients. ...
Background and purpose Accurate placement of an external ventricular drain (EVD) for the treatment of hydrocephalus is of paramount importance for its functionality and in order to minimize morbidity and complications. The aim of this study was to compare two different drain insertion assistance tools with the traditional free-hand anatomical landmark method, and to measure efficacy, safety and precision. Methods Ten cadaver heads were prepared by opening large bone windows centered on Kocher’s points on both sides. Nineteen physicians, divided in two groups (trainees and board certified neurosurgeons) performed EVD insertions. The target for the ventricular drain tip was the ipsilateral foramen of Monro. Each participant inserted the external ventricular catheter in three different ways: 1) free-hand by anatomical landmarks, 2) neuronavigation-assisted (NN), and 3) XperCT-guided (XCT). The number of ventricular hits and dangerous trajectories; time to proceed; radiation exposure of patients and physicians; distance of the catheter tip to target and size of deviations projected in the orthogonal plans were measured and compared. Results Insertion using XCT increased the probability of ventricular puncture from 69.2 to 90.2 % (p = 0.02). Non-assisted placements were significantly less precise (catheter tip to target distance 14.3 ± 7.4 mm versus 9.6 ± 7.2 mm, p = 0.0003). The insertion time to proceed increased from 3.04 ± 2.06 min. to 7.3 ± 3.6 min. (p Conclusion This ex vivo study demonstrates a significantly improved accuracy and safety using either NN or XCT-assisted methods. Therefore, efforts should be undertaken to implement these new technologies into daily clinical practice. However, the accuracy versus urgency of an EVD placement has to be balanced, as the image-guided insertion technique will implicate a longer preparation time due to a specific image acquisition and trajectory planning.
... In order to improve these results, a number of different strategies have been presented. One solution would be to use intraoperative imaging such as ultrasound [4][5][6][7][8] or fluoroscopy [9] for guidance and verification of the position of the tip of the catheter. The main disadvantage of these systems is the need for additional equipment and setup in the operating room. ...
Inaccurate placement of external ventricular drains (EVDs) is a common issue in cerebrospinal diversion procedures. The conventional freehand technique results in a high fraction of sub-optimally placed catheters, and the use of image guidance can improve these results. The purpose of this paper is the validation of the use of an average model for guidance of EVD procedures.
Three neurosurgeons have tested the model-based technique on three normal volunteers, and we have compared the model-based technique to the freehand technique and neuronavigation based on volunteer-specific images.
Our results show that the surgeons perform significantly better when using the model-based technique than when using the freehand technique.
Our results suggest that the use of an average model may improve the accuracy of catheter placements. However, further refinement of the method and testing in a clinical setting is required.
Objective:
External ventricular drains (EVDs) are used to monitor and treat elevated intracranial pressure. EVDs are often placed blindly without the use of imaging guidance, and successful placement with respect to pass attempts and final catheter location may suffer as a result of this freehand technique.
Methods:
A systematic literature search was conducted in PubMed, Embase, Web of Science, and Cochrane databases to identify studies pertaining to freehand EVD placement through March 30, 2022. Studies were included if they reported percentage of EVDs placed successfully on the first pass attempt, or final catheter location as defined by the Kakarla Grading System. Pooled weighted incidence estimates and 95% confidence intervals (95%CI) were calculated using a random effects model.
Results:
Of the 2964 results returned from the literature search, 39 studies were included in this meta-analysis. These studies reported on 6313 EVDs placed via freehand technique in 6070 patients with the following respective incidence: successful EVD placement on the first attempt (78%, 95%CI: 67-86%); placement with a Kakarla Grade of 1 (optimal location) (72%, 95%CI: 66-77%); hemorrhage (7%, 95%CI: 6-10%), and infection (5%, 95%CI: 3-8%).
Conclusions:
Only 78% of EVDs in this meta-analysis were placed successfully on the first pass, and only 72% of final placements were deemed optimal. This represents a relatively high rate of suboptimal outcomes with respect to EVD placement, which could potentially be avoided with the use of navigation-assisted placement techniques.
Background
Insertion of external ventricular drain (EVD) is one of the most common neurosurgical procedures performed worldwide. This is generally performed freehand, on the basis of anatomical landmarks. There is significant variability in the reported accuracy of freehand placement, lacking Level I evidence. We present the first meta-analysis of freehand EVD placement accuracy and technologies or techniques to enhance accuracy.
Methods
We report a systematic review of the Pubmed, Embase, and Cochrane Central databases according to MOOSE (Meta-analysis Of Observational Studies) guidelines. 37 studies were included for qualitative analysis and 19 studies (2983 cases) for quantitative analysis.
Results
There is substantial heterogeneity in the outcome measures used to report EVD placement accuracy. Of those nineteen studies reporting accuracy using the Kakarla grading system the mean rate of ideal ipsilateral frontal horn placement was 73% (standard deviation ±7%). The use of formal stereotaxic guidance is consistently reported to improve accuracy to >90%, although with variable outcome measures. However, the reported efficacy of other guidance devices or techniques is highly variable. The quality of studies directly comparing all existing non-stereotaxic devices with freehand EVD placement is poor and precludes any assertion of superiority to freehand insertion.
Conclusions
We provide the first meta analysis of freehand placement accuracy. There is insufficient data to perform a meta-analysis of the relative efficacy of interventions to improve accuracy. Qualitative synthesis of reports of stereotaxic guidance is suggestive of higher accuracy than freehand placement.
The use of intraoperative ultrasound in emergency cranial neurosurgical procedures is not well described. It may improve surgical outcomes and is useful when other neuro-navigation systems are not readily available. We provide a practical guide for neurosurgical trainees to utilize ultrasound for various emergency cranial neurosurgical procedures, including lesion localization, insertion of an external ventricular drain, and shunt revision surgery. Intraoperative ultrasound is a useful modality for urgent neurosurgical procedures.
Introduction
The accurate placement of the ventricular catheter (VC) is critical in reducing the incidence of proximal failure of ventriculoperitoneal shunts (VPSs). The standard freehand technique is based on validated external anatomical landmarks but remains associated with a relatively high rate of VC malposition. Already proposed alternative methods have all their specific limitations. Herein, we evaluate the accuracy of our adapted freehand technique based on an individualized radio-anatomical approach. Reproducing the preoperative imaging on the patient’s head using common anatomical landmarks allows to define stereotactic VC coordinates to be followed at surgery.
Material and methods
Fifty-five consecutive patients treated with 56 VPS between 11/2005 and 02/2020 fulfilled the inclusion criteria of this retrospective study. Burr hole coordinates, VC trajectory, and length were determined in all cases on preoperative computed tomography (CT) scan and were accurately reported on patients’ head. The primary endpoint was to evaluate VC placement accuracy. The secondary endpoint was to evaluate the rate and nature of postoperative VC-related complications.
Results
Our new technique was applicable in all patients and no VC-related complications were observed. Postoperative imaging showed VC optimally placed in 85.7% and sub-optimally placed in 14.3% of cases. In all procedures, all the holes on the VC tip were found in the ventricular system.
Conclusions
This simple individualized technique improves the freehand VC placement in VPS surgery, making its accuracy comparable to that of more sophisticated and expensive techniques. Further randomized controlled studies are required to compare our results with those of the other available techniques.
Background:
Accurate ventricular catheter (VC) placement plays an important role in reducing the risk of ventriculoperitoneal shunt failure. Free-hand VC insertion is associated with a significant misplacement rate. Consequently, several expensive alternative methods that are unfortunately not available worldwide have been used. To overcome these limitations, we developed a simple surgical technique based on radio-anatomical landmarks aimed at reducing VC's misplacements.
Method:
We reproduce the preoperative imaging on the patient's head using common anatomical landmarks. This allows defining stereotactic VC coordinates to be followed during the surgical procedure.
Conclusion:
This simple and cost-effective method improves VC insertion accuracy.
BACKGROUND
Kocher's point (KP) and its variations have provided standard access to the frontal horn (FH) for over a century. Anatomic understanding of white matter tracts (WMTs) has evolved, now positioning us to better inform the optimal FH trajectory.
OBJECTIVE
To (1) undertake a literature review analyzing entry points (EPs) to the FH; (2) introduce a purpose-built WMT-founded superior frontal sulcus parafascicular (SFSP)-EP also referred to as the Kassam-Monroy entry point (KM-EP); and (3) compare KM-EP with KP and variants with respect to WMTs.
METHODS
(1) Literature review (PubMed database, 1892-2018): (a) stratification based on the corridor: i. ventricular catheter; ii. through-channel endoscopic; or iii. portal; (b) substratification based on intent: i. preoperatively planned or ii. intraoperative (postdural opening) for urgent ventricular drainage. (2) Anatomic comparisons of KM-EP, KP, and variants via (a) cadaveric dissections and (b) magnetic resonance-diffusion tensor imaging computational 3D modeling.
RESULTS
A total of 31 studies met inclusion criteria: (a) 9 utilized KP coordinate (1 cm anterior to the coronal suture (y-axis) and 3 cm lateral of the midline (x-axis) approximated by the midpupillary line) and 22 EPs represented variations. All 31 traversed critical subcortical WMTs, specifically the frontal aslant tract, superior longitudinal fasciculus II, and inferior fronto-occipital fasciculus, whereas KM-EP (x = 2.3, y = 3.5) spares these WMTs.
CONCLUSION
KP (x = 3, y = 1) conceived over a century ago, prior to awareness of WMTs, as well as its variants, anatomically place critical WMTs at risk. The KM-EP (x = 2.3, y = 3.5) is purpose built and founded on WMTs, representing anatomically safe access to the FH. Correlative clinical safety, which will be directly proportional to the size of the corridor, is yet to be established in prospective studies.
The insertion of an external ventricular drainage (EVD) is a common practice in neurosurgery, especially in pediatrics. This approach has been developed and evolved in the last century and is currently considered a standard technique.
However, in spite of this standardization, EVD placement can be associated with different complications, and the infection is the most important one, with significant associated morbidity and mortality.
The present chapter summarizes the main aspects about EVDs in the pediatric population, emphasizing in the indications for its insertion, its complications, and the protocols to avoid bad functional results.
Objective:
Optimal ventricular catheter positioning is able to reduce the risk of catheter dysfunction, and subsequently the risk of multiple revision surgery. The objective of our study was to compare the proportion of optimal ventricular catheter placements in a cohort of patients operated for ventriculoperitoneal (VP) shunt between a free-hand group and a neuronavigated group.
Patients and methods:
Twenty patients with hydrocephalus requiring VP shunt were prospectively included in this study. Patients were divided into two groups; the ventricular catheter was positioned using free-hand method (n=10) or magnetic navigation system (n=10). For the two groups, clinical baseline characteristics, etiology of hydrocephaly and initial ventricular size were assessed. The main judgment criterion was the proportion of optimal catheter placements defined by the presence of all catheter holes in the ventricle, evaluated on post-operative CT scan.
Results:
There was no initial difference between the two groups in terms of hydrocephalus etiology or initial ventricular size. The number of optimal catheter placements was 6/10 in the neuronavigated group versus 1/10 in the free-hand group (p<0.05). There were no complications during post-operative period in either cohort.
Conclusion:
In patients suffering from hydrocephaly, the use of an electromagnetic neuronavigation system for ventricular catheter placement significantly improved the proportion of optimal catheter placements. Long-term follow-up is necessary to evaluate the number of revision surgeries and the cost in each group.
Long-term anticoagulation is often considered to be a relative contraindication to shunt surgery for patients with normal pressure hydrocephalus (NPH). While the overall risk of bleeding associated with shunt placement is low, the risk of bleeding in the elderly is increased, particularly with regard to immediate intracerebral hemorrhage or delayed subdural hematoma (SDH) during or after CSF shunting. Furthermore, NPH patients receiving antithrombotic therapy are at a significantly increased risk of hemorrhagic complication compared to patients who are not on antithrombotic therapy. Given the advanced age, gait impairment, and dementia associated with NPH, the bleeding and thrombotic risk may be even higher in NPH than the general population receiving antithrombotic therapy. Therefore, consultation with a hematologist and/or cardiologist is warranted in order to determine which patients can safely suspend antithrombotic therapy prior to surgery versus those who require bridging. Preoperatively, antiplatelet therapy should be stopped at least 7–14 days prior to surgery, whereas warfarin therapy should be stopped at least 5–7 days prior to surgery and/or bridged with a short-acting anticoagulant, in general. Operative considerations that can reduce the risk of hemorrhagic complication include incision of the pia mater prior to ventricular catheter insertion, potential use of intraoperative imaging guidance, and placement of an adjustable and gravity-assisted shunt valve to lower the risk of overdrainage. In the outpatient setting, gradual lowering of the pressure setting should be performed over time until a balance is reached between maximum symptomatic improvement and the onset of symptoms suggestive of low intracranial pressure (e.g., orthostatic headache and dizziness). Postoperatively, the time to resumption of antithrombotic therapy depends on the patients’ individual risk of thrombosis and bleeding as well as radiographic evaluation for intracranial hemorrhage. In summary, patients on long-term antithrombotic therapy can be safely and effectively evaluated and treated for NPH, with the use of appropriate perioperative and postoperative management.
This cadaveric study outlines the efficiency, safety and precision of cerebral ventricular catheter placement comparing classical freehand technique using anatomical landmarks, neuronavigation and XperCT-guided assistance.
and Importance: Three-dimensional ultrasound navigation has been performed to assist in resection of cranial and spinal tumors, but to the best of our knowledge, no one has described the use of real-time three-dimensional ultrasound navigation in resection of neck tumors beyond biopsy.
This case report describes the use of three-dimensional ultrasonic navigation in assisting with resection of a large neck paraganglioma. The three-dimensional ultrasonic navigation improved real-time visualization of the carotid arteries as well as the trachea and other vital structures.
The use of three-dimensional ultrasound navigation should be considered for use in aiding resection of large neck tumors, as it can allow for more efficient and safer tumor resection.
OBJECTIVE
We have integrated a neuronavigation system into an ultrasound scanner and developed a single-rack system that enables the surgeon to perform frameless and armless stereotactic neuronavigation using intraoperative three-dimensional ultrasound data as well as preoperative magnetic resonance or computed tomographic images. The purpose of this article is to describe our two-rack prototype and present the results of our work on image quality enhancement.
DESCRIPTION OF INSTRUMENTATION
The system consists of a high-end ultrasound scanner, a modest-cost computer, and an optical positioning/digitizer system. Special technical and clinical efforts have been made to achieve high image quality. A special interface between the ultrasound instrument and the navigation computer ensures rapid transfer of digital three-dimensional data with no loss of image quality.
OPERATIVE TECHNIQUE
The positioning system tracks the position and orientation of the patient, the ultrasound probe, the pointer, and various surgical instruments. This makes it possible to update the three-dimensional map during surgery and navigate by ultrasound data in a similar manner as with magnetic resonance data.
METHODS
The two-rack prototype has been used for clinical testing since November 1997 at the University Hospital in Trondheim.
EXPERIENCE AND RESULTS
The image quality improvements have enabled us, in most cases, to extract information from ultrasound with clinical value similar to that of preoperative magnetic resonance imaging. The overall clinical accuracy of the ultrasound-based navigation system is expected to be comparable to or better than that of a magnetic resonance imaging-based system.
CONCLUSION
The SonoWand system enables neuronavigation through direct use of intraoperative three-dimensional ultrasound. Further research will be necessary to explore the potential clinical value and the limitations of this technology.
Object:
Ventricular catheter shunt malfunction is the most common reason for shunt revision. Optimal ventricular catheter placement can be exceedingly difficult in patients with small ventricles or abnormal ventricular anatomy. Particularly in children and in premature infants with small head size, satisfactory positioning of the ventricular catheter can be a challenge. Navigation with electromagnetic tracking technology is an attractive and innovative therapeutic option. In this study, the authors demonstrate the advantages of using this technology for shunt placement in children.
Methods:
Twenty-six children ranging in age from 4 days to 14 years (mean 3.8 years) with hydrocephalus and difficult ventricular anatomy or slit ventricles underwent electromagnetic-guided neuronavigated intraventricular catheter placement in a total of 29 procedures.
Results:
The single-coil technology allows one to use flexible instruments, in this case the ventricular catheter stylet, to be tracked at the tip. Head movement during the operative procedure is possible without loss of navigation precision. The intraoperative catheter placement documented by screenshots correlated exactly with the position on the postoperative CT scan. There was no need for repeated ventricular punctures. There were no operative complications. Postoperatively, all children had accurate shunt placement. The overall shunt failure rate in our group was 15%, including 3 shunt infections (after 1 month, 5 months, and 10 months) requiring operative revision and 1 distal shunt failure. There were no proximal shunt malfunctions during follow-up (mean 23.5 months).
Conclusions:
The electromagnetic-guided neuronavigation system enables safe and optimal catheter placement, especially in children and premature infants, alleviating the need for repeated cannulation attempts for ventricular puncture. In contrast to stereotactic techniques and conventional neuronavigation, there is no need for sharp head fixation using a Mayfield clamp. This technique may present the possibility of reducing proximal shunt failure rates and costs for hydrocephalus treatment in this age cohort.
Purpose
We present a new system for 3D ultrasound-guided placement of cerebral ventricle catheters. The system has been developed with the aim to provide accurate ultrasound-based guidance with only minimal changes to the current surgical technique and workflow.
Methods
The system consists of a pre-calibrated navigation adapter for the catheter and a reference frame attached to a standard surgical retractor in addition to an ultrasound-based navigation system with a probe that fits on top of a standard burr hole.
Results
The accuracy of the pre-calibrated system has been evaluated, and our measurements indicate that the accuracy of the pre-calibrated system is better than 3 mm. We also present a clinical case.
Conclusions
The navigation accuracy is considered sufficient for clinical use, and initial clinical tests are promising. Further testing will be necessary to fully evaluate the performance of the system in a clinical setting.
As many as 40% of shunts fail in the first year, mainly due to proximal obstruction. The role of catheter position on failure rates has not been clearly demonstrated. The authors conducted a prospective cohort study of navigated shunt placement compared with standard blind shunt placement at 3 European centers to assess the effect on shunt failure rates.
All adult and pediatric patients undergoing de novo ventriculoperitoneal shunt placement were included (patients with slit ventricles were excluded). The first cohort underwent standard shunt placement using anatomical landmarks. All centers subsequently adopted electromagnetic (EM) navigation for routine shunt placements, forming the second cohort. Catheter position was graded on postoperative CT in both groups using a 3-point scale developed for this study: (1) optimal position free-floating in CSF; (2) touching choroid or ventricular wall; or (3) intraparenchymal. Episodes and type of shunt revision were recorded. Early shunt failure was defined as that occurring within 30 days of surgery. Patients with shunts were followed-up for 12 months in the standard group, for a median of 6 months in the EM-navigated group, or until shunt failure.
A total of 75 patients were included in the study, 41 with standard shunts and 34 with EM-navigated shunts. Seventy-four percent of navigated shunts were Grade 1 compared with 37% of the standard shunts (p=0.001, chi-square test). There were no Grade 3 placements in the navigated group, but 8 in the standard group, and 75% of these failed. Early shunt failure occurred in 9 patients in the standard group and in 2 in the navigated group, reducing the early revision rate from 22 to 5.9% (p=0.048, Fisher exact test). Early shunt failures were due to proximal obstruction in 78% of standard shunts (7 of 9) and in 50% of EM-navigated shunts (1 of 2).
Noninvasive EM image guidance in shunt surgery reduces poor shunt placement, resulting in a significant decrease in the early shunt revision rate.
Accurate placement of ventricular catheters in children with small ventricles can be difficult. Too often, shunt catheters are misplaced with regard to optimal position and trajectory. The objective of this study was to determine whether neuronavigation-guided free-hand placement of ventricular catheters is an effective adjunct for children with hydrocephalus and small ventricles.
Nine children with hydrocephalus (ages 1-12 years) participated in this study. Four children were diagnosed as suffering from slit ventricle syndrome and 5 children had small to mildly dilated ventricles. Of the 9 shunted children, 6 underwent previous shunt placements, and 1 child previously underwent an endoscopic third ventriculostomy. In 8 children the primary procedure was insertion of ventricular catheters using a frameless neuronavigation system. In 1 child, the neuronavigation system was used after failure to insert the ventricular catheter using a standard technique. All children showed significant improvement of their symptoms and signs following the procedure and none of them required shunt revision during the follow up period (mean 8+/-5 months).
The usage of a neuronavigation system is safe and may be beneficial for optimal positioning and trajectory of ventricular catheters in children with small ventricles or an abnormal ventricular anatomy.
The standard method of ventriculostomy catheter placement is a freehand pass technique using surface anatomical landmarks. This study was undertaken to determine the accuracy of successful ventriculostomy procedures performed at a single institution's intensive care unit (ICU). The authors hypothesized that use of surface anatomical landmarks alone with successful results frequently do not correlate with desirable catheter tip placement.
Retrospective evaluation was performed on the head computed tomography (CT) scans of 97 patients who underwent 98 freehand pass ventriculostomy catheter placements in an ICU setting. Using the postprocedure CT scans of the patients, 3D measurements were made to calculate the accuracy of ventriculostomy catheter placement.
The mean distance (+/- standard deviation [SD]) from the catheter tip to the Monro foramen was 16 +/- 9.6 mm. The mean distance (+/- SD) from the catheter tip to the center of the bur hole was 87.4 +/- 14.0 mm. Regarding accurate catheter tip placement, 56.1% of the catheter tips were in the ipsilateral lateral ventricle, 7.1% were in the contralateral lateral ventricle, 8.2% were in the third ventricle, 6.1% were within the interhemispheric fissure, and 22.4% were within extraventricular spaces.
The accuracy of freehand ventriculostomy catheterization at the authors' institution typically required 2 passes per successful placement, and, when successful, was 1.6 cm from the Monro foramen. More importantly, 22.4% of these catheter tips were in nonventricular spaces. Although many neurosurgeons believe that the current practice of ventriculostomy is good enough, the results of this study show that there is certainly much room for improvement.
The most frequent encephalographic abnormality in children, and perhaps also in adults, is enlargement of the lateral ventricles. My associates and I have felt the need of a quantitative expression to describe more accurately the degree of enlargement and to define with some precision, if possible, the normal limits of ventricular size. It is assumed, in spite of a few scattered observations reported in the literature to the contrary, that the cerebral ventricles are of a relatively fixed size and shape and, in the absence of disease, do not vary significantly from day to day. Further systematic study is desirable to establish this point. The simplest measurement to make, and at the same time one of the most significant, is the transverse diameter of the anterior horns on a film exposed in the anteroposterior projection with the posterior part of the skull down. This allows filling of the anterior horns
Surgical innovation is an important part of surgical practice. Its assessment is complex because of idiosyncrasies related to surgical practice, but necessary so that introduction and adoption of surgical innovations can derive from evidence-based principles rather than trial and error. A regulatory framework is also desirable to protect patients against the potential harms of any novel procedure. In this first of three Series papers on surgical innovation and evaluation, we propose a five-stage paradigm to describe the development of innovative surgical procedures.
Object:
The objective of this study was to compare the accuracy of 3 methods of ventricular catheter placement during CSF shunt operations: the freehand technique using surface anatomy, ultrasonic guidance, and stereotactic neuronavigation.
Methods:
This retrospective cohort study included all patients from a single institution who underwent a ventricular CSF shunting procedure in which a new ventricular catheter was placed between January 2005 and March 2010. Data abstracted for each patient included age, sex, diagnosis, method of ventricular catheter placement, site and side of ventricular catheter placement, Evans ratio, and bifrontal ventricular span. Postoperative radiographic studies were reviewed for accuracy of ventricular catheter placement. Medical records were also reviewed for evidence of shunt failure requiring revision through December 2011. Statistical analysis was then performed comparing the 3 methods of ventricular catheter placement and to determine risk factors for inaccurate placement.
Results:
There were 249 patients included in the study; 170 ventricular catheters were freehand passed, 51 were placed using stereotactic neuronavigation, and 28 were placed under intraoperative ultrasonic guidance. There was a statistically significant difference between freehand catheters and stereotactic-guided catheters (p<0.001), as well as between freehand catheters and ultrasound-guided catheters (p<0.001). The only risk factor for inaccurate placement identified in this study was use of the freehand technique. The use of stereotactic neuronavigation and ultrasonic guidance reduced proximal shunt failure rates (p<0.05) in comparison with a freehand technique.
Conclusions:
Stereotactic- and ultrasound-guided ventricular catheter placements are significantly more accurate than freehand placement, and the use of these intraoperative guidance techniques reduced proximal shunt failure in this study.
Background:
Intra-ventricular hemorrhage (IVH) is a frequent cause of shunt-dependent hydrocephalus. The management of IVH in preterm babies remains a challenge both for neonatologists and pediatric neurosurgeons, compounded by the lack of low-risk, validated therapy techniques.
Objective:
The aim of this study was to evaluate the feasibility and safety of a novel technique involving the ultrasound-guided placement of a central catheter connected with a Rickham-Capsule in a cohort of preterm, low-birth-weight babies with post-hemorrhagic hydrocephalus (PHH).
Methods:
Eight preterm infants with PHH in which a Rickham-Capsule was placed from 2008-2012 were included. Conventional surgical techniques were used in four preterm infants; whereas in the other four preterm babies ultrasound guided catheter placement was performed with an 8 MegaHertz (MHz) micro convex transducer from LOGIQ 9, GE Healthcare; whereby the anterior fontanel was used as an acoustic window.
Results:
Overall gestational age was 24-31 weeks, mean age at operation was 20.1 (7-36) days, mean birth weight 972.5±370 g, mean weight at first surgical intervention 1023.75±400.4 g. Six patients had bilateral IVH II-III°, two patients had parenchymal involvement. Using the conventional approach, incorrect catheter placement occurred in one of four patients below 1000 g, whereas none of the ultrasound guided cases needed correction.
Conclusions:
Ultrasound-guided neuronavigation represents a relevant tool in the treatment of hydrocephalus in preterm infants through increased accuracy in placement of a central catheter connected to a Rickham-Capsule. The benefit of utilizing this form of neuronavigation needs to be assessed through corresponding standardized studies.
The blind free-hand technique for external ventricular drain (EVD) placement sometimes requires multiple attempts, and catheter location is often less than ideal. Our institution has adapted an intraoperative ultrasound-guided ventriculostomy technique for the placement of EVDs at the bedside. Our experience with ultrasound at the bedside has proven to be invaluable in certain circumstances. We present three cases of strategic EVD catheter trajectories that were made possible at the bedside with the use of ultrasound.
Illustrative cases were chosen from a larger prospective study investigating the ultrasound-guided EVD technique. A portable ultrasound with a "burr hole" probe was used with modification of the standard surgical technique for placement of EVDs at the bedside.
Case 1 describes an unexpected re-hemorrhage that was first realized by the ultrasound image obtained during the bedside EVD placement procedure. The catheter was purposefully directed across midline to the more prominent ventricle on the contralateral side based on this real-time finding. Case 2 describes how ultrasound was used to salvage the failed free-hand procedure and cannulate an extremely small ventricular space at the bedside. Case 3 describes an unconventionally placed burr hole that provided a customized trajectory in which the EVD catheter was placed just laterally and inferior to a large frontal hematoma.
Ultrasound-guided bedside EVD placement allows EVD trajectories to be customized based on real-time information to accommodate for distorted and dynamic anatomy of the brain and its ventricles.
The accurate position of the ventricular catheter inside the frontal horn of the lateral ventricle is essential to prevent proximal failure in shunt surgery. For optimal placement, endoscopic- and image-guided techniques are available.
We introduce a newly constructed tool for quick and safe placement of ventricular catheters. It is mounted on a fixation device and therefore allows the surgeon's optimal concentration on the catheter insertion and feeling for the penetrated tissue. To check the feasibility of the new device, we performed a study with 4 patients.
Two patients with communicative and 2 patients with noncommunicative hydrocephalus underwent ventricular catheter placement using the new shunt placement tool. Three patients had a complex anatomy of the ventricular system.
In all 4 procedures, correct placement of the ventricular catheters was achieved. The additional time needed for preparations did not exceed 15 minutes. The comparison of the postoperative computed tomography scans with the preoperative planning showed good accuracy of the instrument with a mean deviation of the catheter tips from the planned position of 1.5 mm (range 1.0-2.1 mm).
The new tool allows safe and quick placement of ventricular catheters. The adjustment of the tool to the planned trajectory is performed before catheter insertion and allows optimal concentration on the insertion procedure and the fingertip feeling for the penetrated tissue.
Surgical innovation is an important part of surgical practice. Its assessment is complex because of idiosyncrasies related to surgical practice, but necessary so that introduction and adoption of surgical innovations can derive from evidence-based principles rather than trial and error. A regulatory framework is also desirable to protect patients against the potential harms of any novel procedure. In this first of three Series papers on surgical innovation and evaluation, we propose a five-stage paradigm to describe the development of innovative surgical procedures.
To study the safety and accuracy of ventriculostomy by neurosurgical trainees.
Initial computed tomographic studies of 346 consecutive patients who underwent bedside ventriculostomy were reviewed retrospectively. Diagnosis, catheter tip location, midline shift, and procedural complications were tabulated. To analyze catheter placement, we used a new grading system: Grade 1, optimal placement in the ipsilateral frontal horn or third ventricle; Grade 2, functional placement in the contralateral lateral ventricle or noneloquent cortex; and Grade 3, suboptimal placement in the eloquent cortex or nontarget cerebrospinal fluid space, with or without functional drainage. Statistical analysis was performed using Fisher's exact test and a weighted kappa coefficient.
Diagnoses included the following: subarachnoid hemorrhage, n = 153 (44%); trauma, n = 64 (18%); intracerebral hemorrhage/intraventricular hemorrhage, n = 63 (18%); and other, n = 66 (20%). There were 266 (77%) Grade 1, 34 (10%) Grade 2, and 46 (13%) Grade 3 catheter placements. Hemorrhagic complications occurred in 17 (5%). Four patients (1.2%) were symptomatic, with two (0.6%) requiring surgery. Inter- and intraobserver agreement was almost perfect (kappa = 0.846 and 0.922, respectively) as applied to our grading system. Rates of suboptimal placement were highest in patients with midline shift (P = 0.059) and trauma (P = 0.0001). Rates of optimal placement were highest in patients with subarachnoid hemorrhage (P = 0.003) and when the catheter was placed ipsilateral to the side of midline shift (P = 0.063). Neither the resident's training experience nor the side of placement seemed to affect accuracy.
Bedside ventriculostomy is a safe and accurate procedure for intracranial pressure monitoring and cerebrospinal fluid drainage.
The goal of this study was to compare the freehand technique of catheter placement using external landmarks with the technique of using the Ghajar Guide for this procedure. The placement of a ventricular catheter can be a lifesaving procedure, and it is commonly performed by all neurosurgeons. Various methods have been described to cannulate the ventricular system, including the modified Friedman tunnel technique in which a soft polymeric tube is inserted through a burr hole. Paramore, et al., have noted that two thirds of noninfectious complications have been related to incorrect positioning of the catheter.
Forty-nine consecutive patients were randomized between either freehand or Ghajar Guide-assisted catheter placement. The target was the foramen of Monro, and the course was through the anterior horn of the lateral ventricle approximately 10 cm above the nasion, 3 cm from the midline, to a depth of 5.5 cm from the inner table of the skull. In all cases, the number of passes was recorded for successful cannulation, and pre- and postplacement computerized tomography scans were obtained. Calculations were performed to determine the bicaudate index and the distance from the catheter tip to the target point.
Successful cannulation was achieved using either technique; however, the catheters placed using the Ghajar Guide were closer to the target.
We have integrated a neuronavigation system into an ultrasound scanner and developed a single-rack system that enables the surgeon to perform frameless and armless stereotactic neuronavigation using intraoperative three-dimensional ultrasound data as well as preoperative magnetic resonance or computed tomographic images. The purpose of this article is to describe our two-rack prototype and present the results of our work on image quality enhancement.
The system consists of a high-end ultrasound scanner, a modest-cost computer, and an optical positioning/digitizer system. Special technical and clinical efforts have been made to achieve high image quality. A special interface between the ultrasound instrument and the navigation computer ensures rapid transfer of digital three-dimensional data with no loss of image quality.
The positioning system tracks the position and orientation of the patient, the ultrasound probe, the pointer, and various surgical instruments. This makes it possible to update the three-dimensional map during surgery and navigate by ultrasound data in a similar manner as with magnetic resonance data.
The two-rack prototype has been used for clinical testing since November 1997 at the University Hospital in Trondheim.
The image quality improvements have enabled us, in most cases, to extract information from ultrasound with clinical value similar to that of preoperative magnetic resonance imaging. The overall clinical accuracy of the ultrasound-based navigation system is expected to be comparable to or better than that of a magnetic resonance imaging-based system.
The SonoWand system enables neuronavigation through direct use of intraoperative three-dimensional ultrasound. Further research will be necessary to explore the potential clinical value and the limitations of this technology.
Endoscopically assisted ventricular catheter placement has been reported to reduce shunt failure in uncontrolled series. The authors investigated the efficacy of this procedure in a prospective multicenter randomized trial.
Children younger than 18 years old who were scheduled for their first ventriculoperitoneal (VP) shunt placement were randomized to undergo endoscopic or nonendoscopic insertion of a ventricular catheter. Eligibility and primary outcome (shunt failure) were decided in a blinded fashion. An intention-to-treat analysis was performed. The sample size offered 80% power to detect a 10 to 15% absolute reduction in the 1-year shunt failure rate. The authors studied 393 patients from 16 pediatric neurosurgery centers between May 1996 and November 1999. Median patient age at shunt insertion was 89 days. The baseline characteristics of patients within each group were similar: 54% of patients treated with endoscopy were male and 55% of patients treated without endoscopy were male; 30% of patients treated with and 26% of those without endoscopy had myelomeningocele; a differential pressure valve was used in 51% of patients with and 49% of those treated without endoscopy; a Delta valve was inserted in 38% of patients in each group; and a Sigma valve was placed in 9% of patients treated with and 12% of those treated without endoscopy. Median surgical time lasted 40 minutes in the group treated with and 35 minutes in the group treated without endoscopy. Ventricular catheters, which during surgery were thought to be situated away from the choroid plexus, were demonstrated to be in it on postoperative imaging in 67% of patients who had undergone endoscopic insertion and 61% of those who had undergone nonendoscopic shunt placements. The incidence of shunt failure at 1 year was 42% in the endoscopic insertion group and 34% in the nonendoscopic group. The time to first shunt failure was not different between the two groups (log rank = 2.92, p = 0.09).
Endoscopic insertion of the initial VP shunt in children suffering from hydrocephalus did not reduce the incidence of shunt failure.
Endoscopic placement of ventriculoperitoneal (VP) shunt catheters in pediatric patients has been increasingly used in an attempt to minimize the unacceptably high rates of revision. Although this procedure carries an increased expense, there is currently no evidence to support an improved long-term outcome. This paper compares the rates of revision following ventricular catheter placement for shunted hydrocephalus with and without the use of endoscopy.
We retrospectively reviewed the records of all pediatric patients who had undergone shunt placement for hydrocephalus between April 1992 and February 1998. All shunts placed before March 1995 were performed without the endoscope; all subsequent shunts were placed endoscopically. The independent effect of endoscopic versus nonendoscopic shunt placement on subsequent shunt failure was analyzed via multivariate proportional hazards regression model. Multiple logistic regression analyses were used to determine the independent effect of endoscopic placement on subsequent etiology of failure (infection, proximal obstruction, distal malfunction) in the 511 failing shunts.
There were 447 pediatric patients who underwent a total of 965 shunt placements or revisions. Six hundred and five (63%) catheters were placed with the use of the endoscope. Three hundred and sixty (37.3%) were placed without the use of the endoscope. Neuroendoscopy did not independently affect the risk of subsequent shunt failure [Hazard Ratio (95% Confidence Interval) = 1.08 (0.84-1.41)]. Endoscopic placement independently decreased the odds [Odds Ratio (95% Confidence Interval) = 0.56 (0.32-0.93)] of proximal obstruction, increased the odds of distal malfunction [1.52 (1.02-2.72)], and was not associated with infection [1.42 (0.78-2.61)].
Endoscopic assisted ventricular catheter placement decreased the odds of proximal obstruction but failed to improve overall shunt survival in this 6 year experience.
Evaluation of percutaneous CT-controlled ventriculostomy (PCV) in patients with severe traumatic brain injury to measure intracranial pressure as a component of early clinical care. A consecutive series of 52 interventions with PCV was prospectively analyzed with regard to technical success, procedural time, time from the initial cranial computed tomography (CCT) until procedure and transfer to the intensive care unit (ICU). Additionally, the data was compared with a retrospective control group of 12 patients with 13 procedures of conventional burr-hole ventriculostomy (OP-ICP). The PCV was successful in all cases (52 of 52; 95% CI 94-100%). In 1 case a minor hemorrhage into the ipsilateral lateral ventricle was observed on CT scans due to an initially unsuccessful puncture (95% CI 0-6%). No infections occurred (95% CI 0-6%). In the control group with OP-ICP one catheter infection and one unsuccessful catheter placement occurred (each 8%, 95% CI 0-20%). The PCV led to a significant decrease of procedure time from 45 +/- 11 min (OP-ICP) to 20 +/- 12 min (PCV). The interval from the initial CCT until procedure (PCV 28 +/- 11 min, OP-ICP 78 +/- 33 min) and transfer to the ICU (PCV 69 +/- 34 min, OP-ICP 138 +/- 34 min) could also be significantly reduced (each with p<0.05, Mann-Whitney U-test). Percutaneous CT-controlled ventriculostomy is a safe and efficient method for ICP catheter placement during initial trauma room management. It significantly reduces the time of initial trauma room treatment.
Puncture of the ventricular system as one of the most frequently performed operative procedures in neurosurgery is usually done in a freehand way without guiding devices. The objective of this study is to examine whether ultrasonic guidance is able to heighten the accuracy of ventricular tapping.
Real-time imaging via a single burr hole approach is achieved by aid of a bajonet-like shaped transducer with a footprint of 8x8 mm only (EUP-NS32, Hitachi Medical Systems). The needle is advanced towards the frontal horn along a displayed guideline. 51 punctures in 48 patients were performed with ultrasonic guidance and compared to 85 punctures in 67 patients without a guiding device.
The presented ultrasound method was not able to heighten the access rate of ventricular tapping, but it improved correct positioning of the catheter tip inside the frontal horn of the ventricular system significantly.
Robotic applications hold great promise for improving clinical outcomes and reducing complications of surgery. To date, however, there have been few widespread applications of robotic technology in neurosurgery. The authors hypothesized that image-guided robotic placement of a ventriculostomy catheter is safe, highly accurate, and highly reproducible.
Sixteen patients requiring catheter ventriculostomy for ventriculoperitoneal (VP) shunt or reservoir placement were included in this retrospective study. All patients underwent image-guided robotic placement of a ventricular catheter, using a preoperatively defined trajectory.
All catheters were placed successfully in a single pass. There were no catheter-related hemorrhages and no injuries to adjacent neural structures. The mean distance of the catheter tip from the target was 1.5 mm. The mean operative times were 112 minutes for VP shunt placement and 42.3 minutes for reservoir placement. The mean operative times decreased over the course of the study by 49% for VP shunts and by 19% for reservoir placement.
The robotic placement of a ventriculostomy catheter using a preplanned trajectory is safe, highly accurate, and highly reliable. This makes single-pass ventriculostomy possible in all patients, even in those with very small ventricles, and may permit catheter-based therapies in patients who would otherwise be deemed poor surgical candidates because of ventricle size. Robotic placement also permits careful preoperative study and optimization of the catheter trajectory, which may help minimize the risks to bridging veins and sulcal vessels.
The authors present a technique in which real-time ultrasound monitoring is used to aid the insertion of cerebrospinal fluid (CSF) shunt ventricular catheters in children without patent fontanelles. Experience with the technique is reviewed. Intraoperative ultrasound is used to identify the compartments of the lateral ventricles and the choroid plexus prior to catheter insertion. Distance and trajectory to the best location for the hole-bearing segment of the catheter are determined and the catheter is inserted while real-time ultrasound monitoring is performed. Ten pediatric patients without open fontanelles underwent CSF shunt placement with the aid of transcranial ultrasound guidance between July and December 2006. After enlarging an occipital or frontal bur hole to a diameter of 2 cm to accommodate a small-footprint ultrasound probe, a ventricular catheter was carefully advanced into the frontal or occipital horn of the lateral ventricle while continuous ultrasound monitoring was performed. All catheters were inserted with a single pass through the brain. The final position of the ventricular catheter was visualized using intraoperative ultrasound. Postoperative computed tomography scans revealed all ventricular catheters placed accurately into the intended compartment of the ventricular system (for example, frontal horn or trigone). No procedure-related complications were noted. Real-time transcranial ultrasound monitoring through an enlarged bur hole is a feasible, safe, and effective technique for the placement of ventricular catheters in pediatric patients without a patent fontanelle.