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Andrew S Little,
Daniel Kelly,
John Milligan,
Chester Griffiths,
Gail Rosseau,
Daniel M Prevedello,
Ricardo Carrau,
Heidi Jahnke,
Charlene Chaloner,
Judith O'Leary,
Kristina Chapple,
Peter Nakaji,
William L White
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ABSTRACT: Object Patient-reported quality-of-life (QOL) end points are becoming increasingly important health care metrics. To date, no nasal morbidity instrument specifically designed for patients undergoing endonasal skull base surgery has been developed. In this study, the authors describe the development and validation of a site-specific nasal morbidity instrument to assess patient-reported rhinological outcomes following endonasal skull base surgery. Methods Eligible patients included those with planned endonasal transsphenoidal surgery for sellar pathology identified in outpatient neurosurgical clinics of 3 skull base centers from October 2011 to July 2012. An initial 23-question pool was developed by subject matter experts, review of the literature, and from the results of a previous validation study to assess for common rhinological complaints. Symptoms were ranked by patients from "No Problem" to "Severe Problem" on a 6-point Likert scale. Exploratory factor analysis, change scores, and importance rank were calculated to define the final instrument consisting of 12 items (The Anterior Skull Base Nasal Inventory-12, or ASK Nasal-12). Psychometric validation of the final instrument was performed using standard statistical techniques. Results One hundred four patients enrolled in the study. All patients completed the preoperative survey and 100 patients (96%) completed the survey 2-4 weeks after surgery. Internal consistency of the final instrument was 0.88. Concurrent validity measures demonstrated a strong correlation between overall nasal functioning and total scores (p < 0.001). Test-retest reliability measures demonstrated a significant intraclass correlation between responses (p < 0.001). Effect size as calculated by standardized response mean suggested a large effect (0.84). Discriminant validity calculations demonstrated that the instrument was able to discriminate between preoperative and postoperative patients (p < 0.001). Conclusions This prospective study demonstrates that the ASK Nasal-12 is a validated, site-specific, unidimensional rhinological outcomes tool sensitive to clinical change. It can be used in conjunction with multidimensional QOL instruments to assess patient-reported nasal perceptions in endonasal skull base surgery. This instrument is being used as a primary outcome measure in an ongoing multicenter nasal morbidity study. Clinical trial registration no.: NCT01504399 ( ClinicalTrials.gov ).
Journal of Neurosurgery 05/2013; · 2.96 Impact Factor
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ABSTRACT: BACKGROUND:: Endoscopicendonasal approaches to the craniovertebral junction (CVJ) and clivus, which are increasingly performed for ventral skull base pathology, may require disruption of the occipitocondylar joint. OBJECTIVE:: We studied the biomechanical implications at the CVJ of progressive unilateral condylectomy as would be performed through an endonasal exposure. METHODS:: Seven upper cervical human cadaveric specimens (C0-C2) underwent nondestructive biomechanical flexibility testing during flexion-extension, axial rotation, and lateral bending at C0-C1 and C1-C2. Each specimen was tested intact, after an inferior one-third clivectomy, and after stepwise unilateral condylectomy using an anterior approach. Angular range of motion (ROM), lax zone, and stiff zone were determined and compared to the intact state. RESULTS:: At C0-C1, mobility during flexion-extension and axial rotation increased significantly with progressive condylectomy. ROM increased from 14.3±2.7 to 20.4±5.2 degrees during flexion and from 6.7±3.5 to 10.8±3.0 degrees during right axial rotation after 75% condyle resection (p <0.01). At C1-C2, condylectomy had less effect, with ROM increasing from 10.7 ±2.0 to 11.7±2.0 degrees during flexion, 36.9±4.8 to 37.1 ±5.1 degrees during right axial rotation, and 4.3±1.9 to 4.8±3.3 degrees during right lateral bending (not significant). Because of marked instability, the 100% condylectomy condition was untestable. Changes in ROM were more a result of changes in lax zone than in stiff zone. CONCLUSION:: Lower-third clivectomy and unilateral anterior condylectomyas would be performed in an endonasal approach cause progressive hypermobility at the CVJ. Based on biomechanical criteria, craniocervical fusion is indicated for patients who undergo greater than 75% anterior condylectomy.
Neurosurgery 02/2013; · 2.79 Impact Factor
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ABSTRACT: Object The short-term cost associated with subspecialized surgical care is an increasingly important metric and economic concern. This study sought to determine factors associated with hospital charges in patients undergoing transsphenoidal surgery for Cushing disease in an effort to identify the drivers of resource utilization. Methods The authors analyzed the Nationwide Inpatient Sample (NIS) hospital discharge database from 2007 to 2009 to determine factors that influenced hospital charges in patients who had undergone transsphenoidal surgery for Cushing disease. The NIS discharge database approximates a 20% sample of all inpatient admissions to nonfederal US hospitals. A multistep regression model was developed that adjusted for patient demographics, acuity measures, comorbidities, hospital characteristics, and complications. Results In 116 hospitals, 454 transsphenoidal operations were performed. The mean hospital charge was $48,272 ± $32,060. A multivariate regression model suggested that the primary driver of resource utilization was length of stay (LOS), followed by surgeon volume, hospital characteristics, and postoperative complications. A 1% increase in LOS increased hospital charges by 0.60%. Patient charges were 13% lower when performed by high-volume surgeons compared with low-volume surgeons and 22% lower in large hospitals compared with small hospitals. Hospital charges were 12% lower in cases with no postoperative neurological complications. The proposed model accounted for 46% of hospital charge variance. Conclusions This analysis of hospital charges in transsphenoidal surgery for Cushing disease suggested that LOS, hospital characteristics, surgeon volume, and postoperative complications are important predictors of resource utilization. These findings may suggest opportunities for improvement.
Journal of Neurosurgery 02/2013; · 2.96 Impact Factor
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ABSTRACT: Object Endoscopic endonasal approaches to the craniovertebral junction (CVJ) and clivus are increasingly performed for ventral skull-base pathology, but the biomechanical implications of these approaches have not been studied. The aim of this study was to investigate the spinal biomechanics of the CVJ after an inferior-third clivectomy and anterior intradural exposure of the foramen magnum as would be performed in an endonasal endoscopic surgical strategy. Methods Seven upper-cervical human cadaveric specimens (occiput [Oc]-C2) underwent nondestructive biomechanical flexibility testing during flexion-extension, axial rotation, and lateral bending at Oc-C1 and C1-2. Each specimen was tested intact, after an inferior-third clivectomy, and after ligamentous complex dissection simulating a wide intradural exposure using an anterior approach. Angular range of motion (ROM), lax zone, and stiff zone were determined and compared with the intact state. Results Modest, but statistically significant, hypermobility was observed after inferior-third clivectomy and intradural exposure during flexion-extension and axial rotation at Oc-C1. Angular ROM increased incrementally between 6% and 12% in flexion-extension and axial rotation. These increases were primarily the result of changes in the lax zone. No significant changes were noted at C1-2. Conclusions Inferior-third clivectomy and an intradural exposure to the ventral CVJ and foramen magnum resulted in hypermobility at Oc-C1 during flexion-extension and axial rotation. Although the results were statistically significant, the modest degree of hypermobility observed compared with other well-characterized CVJ injuries suggests that occipitocervical stabilization may be unnecessary for most patients.
Journal of neurosurgery. Spine 02/2013; · 1.61 Impact Factor
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ABSTRACT: OBJECT: Surgical freedom and the angle of attack influence approach selection for open cranial base approaches, but these concepts have not been well studied in minimal access endoscopic approaches. We therefore developed a methodology to study surgical freedom and angle of attack in two endoscopic transmaxillary transpterygoid approaches, the endonasal ipsilateral uninostril medial maxillotomy and the sublabial Caldwell-Luc anterior maxillotomy. METHODS: Dissections were performed bilaterally in 3 formalin-fixed cadaver heads (6 sides). For each approach, 3 progressively lateral and posterior anatomic targets were identified. Utilizing frameless stereotaxy, surgical freedom using the vector crossproduct method was calculated for both approaches for each target. The mean and maximum possible angles of attack were calculated in the axial and sagittal planes. RESULTS: Compared to the endoscopic endonasal-transmaxillary approach, the endoscopic Caldwell-Luc approach offered significantly greater surgical freedom to the genu of the internal carotid artery (p=0.02), foramen rotundum (p=0.03), and foramen ovale (p=0.03). Mean and maximum possible angles of attack were also significantly different between the two approaches for each target. The Caldwell-Luc approach offered a more bottom-up approach in the sagittal plane and a more head-on approach in the axial plane to each target (p<0.05). CONCLUSIONS: We have successfully developed a model for comparing endoscopic skull base approaches. Both the endonasal medial maxillotomy approach and Caldwell-Luc approach provided endoscopic access to each target. However, the sublabial Caldwell-Luc approach offered greater surgical freedom and a more head-on approach than the endonasal medial maxillotomy. These differences in surgical freedom and angles of attack may be useful to consider when planning minimal access approaches.
World Neurosurgery 02/2013; · 0.68 Impact Factor
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ABSTRACT: : The short-term cost associated with subspecialized surgical care is becoming an increasingly important metric and health economics concern. We sought to determine factors that are associated with hospital charges in patients undergoing transsphenoidal surgery for Cushing's disease in an effort to develop more cost-effective surgical paradigms.
: We analyzed the Nationwide Inpatient Sample (NIS) hospital discharge database from 2007 to 2009 using several multivariate regression models to determine factors that influence hospital charges in patients who had undergone transsphenoidal surgery for Cushing's disease. The NIS discharge database approximates a 20% sample of all inpatient admissions to nonfederal US hospitals. The regression model was adjusted for patient demographics, acuity measures, comorbidities, hospital characteristics, and complications.
: A total of 454 operations performed at 116 hospitals were analyzed. The mean hospital charge was $48,272 ± 32,060. A multivariate regression model suggested that lower hospital charges were associated with higher volume centers (P < 0.001), larger hospitals (P < 0.001), fewer postoperative complications (P = 0.003) and shorter hospital stays (P < 0.001). Patient charges were 18% lower in higher volume centers compared to lower volume centers, and 23% lower in larger hospitals compared to smaller hospitals. Interestingly, 64% of surgical interventions were performed at lower volume hospitals. Hospital charges were 13% lower in cases where there was no postoperative neurological complication.
: Analysis of the NIS database demonstrates that higher surgical volume, larger hospital size, shorter hospital stays, and fewer complications are important variables that impact hospital charges in the surgical management of Cushing's disease. One health economic strategy for providing more cost efficient care may be to develop programs that encourage establishing high volume Cushing's disease centers which can decrease complications and achieve economies of scale.
Neurosurgery 08/2012; 71(2):E548. · 2.79 Impact Factor
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ABSTRACT: The field of anatomy, one of the most ancient sciences, first evolved in Egypt. From the Early Dynastic Period (3100 BC) until the time of Galen at the end of the 2nd century ad, Egypt was the center of anatomical knowledge, including neuroanatomy. Knowledge of neuroanatomy first became important so that sacred rituals could be performed by ancient Egyptian embalmers during mummification procedures. Later, neuroanatomy became a science to be studied by wise men at the ancient temple of Memphis. As religious conflicts developed, the study of the human body became restricted. Myths started to replace scientific research, squelching further exploration of the human body until Alexander the Great founded the city of Alexandria. This period witnessed a revolution in the study of anatomy and functional anatomy. Herophilus of Chalcedon, Erasistratus of Chios, Rufus of Ephesus, and Galen of Pergamon were prominent physicians who studied at the medical school of Alexandria and contributed greatly to knowledge about the anatomy of the skull base. After the Royal Library of Alexandria was burned and laws were passed prohibiting human dissections based on religious and cultural factors, knowledge of human skull base anatomy plateaued for almost 1500 years. In this article the authors consider the beginning of this journey, from the earliest descriptions of skull base anatomy to the establishment of basic skull base anatomy in ancient Egypt.
Neurosurgical FOCUS 08/2012; 33(2):E2. · 2.87 Impact Factor
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ABSTRACT: BACKGROUND: The nasolacrimal duct resides in the wall of the medial nasal cavity and influences minimal access endoscopic transmaxillary approaches to the lateral skull base. We describe an algorithm for surgical approach selection on the basis of the relationship of the target lesion to a line drawn from the anterior nasal SEptum through the Nasolacrimal Duct to the lesion (i.e., SEND line). METHODS: We use the SEND line to estimate the lateral extent in the endonasal middle meatal transmaxillary approach, where the surgeon has good surgical freedom without the use of angled instruments and endoscopes. Lesions with an epicenter lateral to the SEND line were addressed through a sublabial anterior antrostomy transmaxillary corridor. Tumors with a more medially located epicenter, such as those involving the lateral sphenoid sinus and pterygoid plates, were addressed through the endonasal middle meatal corridor. Extensive tumors involving both domains were addressed through a combination approach. RESULTS: We describe three instructive cases in which the approach selection was determined in part by preoperative assessment of the location of the tumor relative to the SEND line. CONCLUSIONS: The endoscopic sublabial transmaxillary and endoscopic endonasal middle meatal transmaxillary approaches are complementary corridors to the anterior skull base that can be used independently or in combination. The location of the target lesion relative to the SEND line as determined on preoperative imaging can serve as a guide for surgical decision making.
World Neurosurgery 02/2012; · 0.68 Impact Factor
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ABSTRACT: The authors describe a rare case of tumoral calcinosis (TC) of the thoracic spine in a 13-year-old boy with thoracic scoliosis. The patient presented with a 2-year history of back pain. He had no personal or family history of bone disease, deformity, or malignancy. Magnetic resonance imaging revealed a heterogeneously enhancing mass involving the T-7 vertebral body and the left pedicle. Computed tomography findings suggested that the mass was calcified and that this had resulted in scalloping of the vertebral body. The lesion was resected completely by using a left T-7 costotransversectomy and corpectomy. The deformity was corrected with placement of a vertebral body cage and pedicle screw fixation from T-5 to T-9. Pathological analysis of the mass demonstrated dystrophic calcification with marked hypercellularity and immunostaining consistent with TC. This represents the third reported case of vertebral TC in the pediatric population. Pediatric neurosurgeons should be familiar with lesions such as TC, which may be encountered in the elderly and in hemodialysis-dependent populations, and may not always require aggressive resection.
Journal of Neurosurgery Pediatrics 12/2011; 8(6):584-7. · 1.53 Impact Factor
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ABSTRACT: The goal of this project was to develop a prospectively-validated, site-specific patient quality of life survey for assessing nasal outcomes following endonasal pituitary and skull base surgery. (ClinicalTrials.gov #NCT01322945) An 9-item patient survey (the ASK Nasal Inventory) focusing on the most common postoperative complaints, such as crusting, sinusitis, pain, and ease of breathing, was developed by the anterior skull base team at the Barrow Neurological Institute. Content was validated in structured patient interviews and by four subject matter experts. This survey was self-administered before and 3 months after surgery to 94 patients (52 endonasal surgery and 42 controls) between October 2010 and June 2011. Standard methods for psychometric evaluation were applied. Cronbach's alpha was 0.83 indicating good internal consistency. Test-retest reliability was excellent in both groups (r = 0.87 and 0.95; P < 0.001). Discriminant validity was determined by comparing mean scores at 3 months in the endonasal and control groups and the difference was significant (13.5 vs. 17.2, P = 0.001). Standardized response mean was 0.17 suggesting that the scale was sensitive to clinical change. Concurrent validity was determined by mean ASK Nasal score for each level of self-reported overall functioning at 3 months (P = 0.001). Preliminary psychometric evaluation of the performance of the ASK Nasal Inventory suggests that it meets criteria as a clinical and research instrument in endonasal surgery. This study also suggests modifications to the instrument, which will serve as key quality of life endpoint in an ongoing multicenter nasal outcomes study.
Pituitary 10/2011; · 1.83 Impact Factor
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ABSTRACT: Pituitary surgery involves operating in the nasal cavity, which is considered a clean-contaminated wound. In the absence of evidence-based guidelines for preventing surgical site infections in trans-sphenoidal surgery, a survey of current opinion on prophylactic antibiotics might help elucidate the current acceptable practices and identify opportunities for prospective clinical trials that could lead to the development of practice guidelines. An on-line, 10-question, multiple-choice survey was distributed by e-mail link to the membership of the International Society of Pituitary Surgeons. Sixty-nine members responded to the survey. Ninety-one percent indicated that there was no strong evidence supporting antibiotic use, but 81% used them to be safe. Ninety percent of respondents used intravenous prophylactic antibiotics, while only 16% used intranasal antibiotics. The most commonly used antibiotics were cephalosporins (72%) and penicillins (21%). Seventy-six percent used antibiotics for 24 h or less after surgery. The most commonly reported indications for prophylactic antibiotics were prevention of meningitis and sinusitis. The results of the survey describe current acceptable practices for chemoprophylaxis in patients undergoing transsphenoidal pituitary surgery.
Pituitary 06/2011; 14(2):99-104. · 1.83 Impact Factor
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ABSTRACT: Perioperative bacterial meningitis after trans-sphenoidal surgery for pituitary and parasellar lesions is an uncommon but serious complication. Little evidence guides the choice of chemoprophylaxis in this setting. To begin to address this deficiency, we investigated the incidence of perioperative meningitis in 442 patients who underwent trans-sphenoidal surgery and received a short chemoprophylaxis regimen with a single agent and did not require lumbar drainage. In 2005 we instituted a standardized antibiotic prophylaxis protocol for trans-sphenoidal surgery that utilized intravenous cefuroxime, a second-generation cephalosporin with broad coverage and excellent spinal fluid penetration, administered 30 min before surgery and 8 h later. The primary endpoint was the incidence of perioperative (within 30 days of surgery) bacterial meningitis. Data from The Barrow Pituitary Outcomes Project, a prospectively maintained patient research database, were supplemented with review of medical records and hospital discharge codes. There were no cases of perioperative meningitis. Three patients developed delayed meningitis associated with persistent or recurrent spinal fluid leakage 2-8 months after surgery. Perioperatively, seven patients received additional antibiotics for urinary tract infections. A single-agent, short-duration chemoprophylaxis regimen for trans-sphenoidal surgery is effective at preventing perioperative meningitis in patients who do not require lumbar drainage after surgery. The results of this regimen compare favorably to historical rates achieved with longer regimens that use two antibiotics. Future studies will investigate the role prophylactic antibiotics play in nasal mucosa healing and sinusitis.
Pituitary 02/2011; 14(4):335-9. · 1.83 Impact Factor
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ABSTRACT: Percutaneous thoracic pedicle screw fixation is challenging because of the complexity of the spinal anatomy and obscuration of normal surgical landmarks by soft tissue. We report a novel percutaneous technique in which intraoperative Iso-C C-arm navigation was used to treat complex thoracic spinal fractures.
Between March and September 2007, percutaneous thoracic pedicle screw fixation was performed with the assistance of intraoperative Iso-C C-arm fluoroscopy in six patients (two males, four females; mean age=33 years, range=16-61 years) with unstable thoracic fractures. The accuracy of pedicle screw placement was assessed by postoperative computed tomography and graded according to the method of Youkilis et al.
Five patients had unstable acute traumatic fractures and one had an osteoporotic burst fracture. Altogether, 19 spinal segments (range=2-4/patient) were fixated using 37 pedicle screws. Pedicle screw misplacement was grade II in 16% and grade III in 3%. None of the patients had neurologic consequences due to screw misplacement, and none required conversion to an open procedure or revision of hardware. There was one wound infection.
Percutaneous thoracic pedicle screw fixation with intraoperative neuronavigation for the stabilization of complex spinal fractures is feasible and associated with acceptable rates of accuracy and morbidity.
World Neurosurgery 12/2010; 74(6):606-10. · 0.68 Impact Factor
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ABSTRACT: Rathke cleft cyst can enlarge and become symptomatic.
To review the clinical data and results of all patients treated by the senior author for a Rathke cleft cyst.
A prospectively maintained surgical database, supplemented with updates from telephone conversations, of all patients presenting to the Barrow Neurological Institute from 1992 to the present was reviewed.
Seventy-three patients (17 males, 56 females; mean age, 40 years; range, 5-80 years) underwent 77 resections. The mean length of follow-up was 27 months (range, 0-129 months). Presenting symptoms included headache (75%), followed by endocrinopathy (49%), and visual symptoms (39%). Preoperative chiasmopathy resolved in 75% and improved in 21% of the patients. Patients' preoperative endocrinopathy resolved at various rates, depending on the specific axis (29%-100%). Endocrinopathies were more likely to resolve in females than males. New postoperative endocrinopathies also occurred (0-8%). Headache resolved (68%) or improved (21%) in most patients. No patient had worsened headaches. Eight patients had a recurrence, 4 of whom underwent reoperation. The presence of squamous metaplasia was the only predictor of recurrence.
Surgical fenestration and/or resection of Rathke cleft cyst via the transsphenoidal approach are a rational choice for surgical management of these lesions when symptomatic. In most cases, visual symptoms and headache can be expected to improve. New persistent endocrine deficits can be expected in a small percentage of patients, but preexisting endocrinopathies resolve in many patients.
Neurosurgery 09/2010; 67(3):837-43; discussion 843. · 2.79 Impact Factor
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ABSTRACT: Treating deep-seated cerebral lesions often requires retracting the brain. Retraction, however, causes clinically significant postoperative neurological deficits in 3% to 9% of intracranial cases.
This pilot study used automated analysis of postoperative magnetic resonance images (MRIs) to determine whether brain retraction caused local anatomic changes to the cerebral neocortex and whether such changes represented sensitive markers for detecting brain retraction injury.
Pre- and postoperative maps of whole-brain cortical thickness were generated from 3-dimensional MRIs of 6 patients who underwent selective amygdalohippocampectomy for temporal lobe epilepsy (5 left hemispheres, 1 right hemisphere). Mean cortical thickness was determined in the inferior temporal gyrus (ITG test), where a retractor was placed during surgery, and in 2 control gyri-the posterior portion of the inferior temporal gyrus (ITG control) and motor cortex control. Regions of cortical thinning were also compared with signs of retraction injury on early postoperative MRIs.
Postoperative maps of cortical thickness showed thinning in the inferior temporal gyrus where the retractor was placed in 5 patients. Postoperatively, mean cortical thickness declined from 4.1 +/- 0.4 mm to 2.9 +/- 0.9 mm in ITG test (P = .03) and was unchanged in the control regions. Anatomically, the region of neocortical thinning correlated with postoperative edema on MRIs obtained within 48 hours of surgery.
Postoperative MRIs can be successfully interrogated for information on cortical thickness. Brain retraction is associated with chronic local thinning of the neocortex. This automated technique may be sensitive enough to detect regions at risk for functional impairment during craniotomy that cannot be easily detected on postoperative structural imaging.
Neurosurgery 09/2010; 67(3 Suppl Operative):ons277-82; discussion ons282. · 2.79 Impact Factor
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ABSTRACT: Endoscopic aqueductoplasty and stenting are a preferred treatment for isolated fourth ventricle syndrome related to membranous aqueductal obstruction. We describe a technique using a small-caliber flexible endoscope that may address some limitations of current strategies.
A 39-year-old woman with hydrocephalus caused by neurococcidiomycosis and a functional right frontal ventriculoperitoneal shunt presented with vomiting and an isolated fourth ventricle. Magnetic resonance imaging showed an enlarged fourth ventricle and exuberant basilar arachnoiditis obstructing the outlet foramina of the fourth ventricle. Ventriculography indicated aqueductal obstruction.
Aqueductoplasty was planned to allow spinal fluid to flow from the fourth ventricle to the ventriculoperitoneal shunt. A stent-endoscope construct was prepared by feeding a flexible endoscope through a ventricular catheter cut 4 cm from the tip. The flexible endoscope was contoured to fit the anatomy of the aqueduct. Uncomplicated aqueductoplasty was performed through a single left frontal burr hole using the stent-endoscope construct to perforate a membranous veil and inspect the fourth ventricle. The stent was deployed over the endoscope using the proximal end of the catheter to deliver and secure the stent as the endoscope was withdrawn.
Aqueductoplasty and stenting using a small-caliber flexible endoscope is feasible. The endoscope can be contoured to suit the anatomy of the aqueduct and improves visualization of the leading edge of the stent during deployment. Furthermore, when the endoscope is used to create the perforation, the target is not obscured by the shaft of the device used to make the perforation.
Neurosurgery 06/2010; 66(6 Suppl Operative):373-4; discussion 374. · 2.79 Impact Factor
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ABSTRACT: To compare the biomechanics of costotransverse process screw fixation with those of pedicle screw fixation in a cadaveric model of the upper thoracic spine.
Ten human thoracic spines were instrumented across the T3-T4 segment with costotransverse and pedicle screws. Nonconstraining pure moments (maximum, 6.0 Nm) were applied to induce flexion, extension, lateral bending, and axial rotation. The range of motion, lax zone, and stiff zone were determined in each specimen in the normal state, after 3-column destabilization, and after instrumentation. After flexibility testing was completed, axial screw pull-out strength was assessed.
In all directions of loading, both fixation techniques significantly decreased lax zone and range of motion at T3-T4 compared with the destabilized state (P < .001). During all loading modes except lateral bending, pedicle screw fixation allowed significantly less range of motion than costotransverse screw fixation. Pedicle screws provided 62% greater resistance to axial pull-out than costotransverse screws.
The costotransverse screw technique seems to provide only moderately stiff fixation of the destabilized thoracic spine. Pedicle screw fixation seems to have more favorable biomechanical properties. These data suggest that the costotransverse process construct is better used as a salvage procedure rather than as a primary fixation strategy.
Neurosurgery 03/2010; 66(3 Suppl Operative):178-82; discussion 182. · 2.79 Impact Factor
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ABSTRACT: The authors introduce a minimal-access subtemporal approach for selective resection of the amygdala and hippocampus in patients with temporal lobe epilepsy and describe seizure and neuropsychological outcomes.
Between October 2003 and April 2007, 41 consecutive patients with intractable unilateral nonlesional temporal lobe epilepsy underwent image-guided subtemporal amygdalohippocampectomy. Baseline characteristics, preoperative evaluations, and seizure outcomes were assessed. Eighteen patients underwent pre- and postoperative neuropsychological testing for cognitive functioning, executive functioning, verbal and visual memory, and mood.
Important aspects of the subtemporal approach include a low temporal keyhole craniotomy, use of image guidance, preservation of the tentorium, incision in the fusiform gyrus, and subpial, en bloc resection of the hippocampus. There were no deaths and no cases of significant postoperative morbidity. At 1 year, 29 of 36 patients (81%) were without seizures or auras. At 2 years, 17 of 23 (74%) patients were seizure- and aura-free. Detailed neuropsychological testing of language, memory, cognitive functioning, and executive functioning suggested that most patients exhibited either stability or improvement in their scores, regardless of language lateralization.
A minimal-access subtemporal approach for amygdalohippocampectomy is an effective treatment for temporal lobe epilepsy yielding encouraging preliminary seizure and neuropsychological outcomes.
Journal of Neurosurgery 05/2009; 111(6):1263-74. · 2.96 Impact Factor
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ABSTRACT: To evaluate the clinical outcome of patients with surgically refractory trigeminal neuralgia (TN) treated with rescue gamma knife radiosurgery (GKRS).
Seventy-nine patients with typical TN received salvage GKRS between 1997 and 2002 at the Barrow Neurological Institute (BNI). All patients had recurrent pain following at least one prior surgical intervention. Prior surgical interventions included percutaneous destructive procedures, microvascular decompression (MVD), or GKRS. Thirty-one (39%) had undergone at least two prior procedures. The most common salvage dose was 80 Gy, although 40-50 Gy was typical in patients who had received prior radiosurgery. Pain outcome was assessed using the BNI Pain Intensity Score, and quality of life was assessed using the Brief Pain Inventory.
Median follow-up after salvage GKRS was 5.3 years. Actuarial analysis demonstrated that at 5 years, 20% of patients were pain-free and 50% had pain relief. Pain recurred in patients who had an initial response to GKRS at a median of 1.1 years. Twenty-eight (41%) required a subsequent surgical procedure for recurrence. A multivariate Cox proportional hazards model suggested that the strongest predictor of GKRS failure was a history of prior MVD (p=0.029). There were no instances of serious morbidity or mortality. Ten percent of patients developed worsening facial numbness and 8% described their numbness as "very bothersome."
GKRS salvage for refractory TN is well tolerated and results in long-term pain relief in approximately half the patients treated. Clinicians may reconsider using GKRS to salvage patients who have failed prior MVD.
International journal of radiation oncology, biology, physics 01/2009; 74(2):522-7. · 4.59 Impact Factor
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ABSTRACT: The long-term outcome of patients treated with gamma knife radiosurgery (GKRS) for typical trigeminal neuralgia has not been fully studied. We evaluated 185 patients who underwent their first GKRS treatment between 1997 and 2003 at the Barrow Neurological Institute.
Follow-up was obtained by surveys and review of medical records. Outcomes were assessed by the Barrow Neurological Institute Pain Intensity Score and Brief Pain Inventory. The most common maximum dose was 80 Gy targeted at the root entry zone. Outcomes are presented for the 136 (74%) patients for whom more than 4 years of clinical follow-up data were obtained.
Treatment failed in 33% of the cohort within 2 years, but only an additional 1% relapsed after 4 years. Actuarial analysis demonstrated that 32% of patients were pain-free off medication and 63% had at least a good outcome at 7 years. When GKRS was used as the primary treatment, 45% of the patients were pain-free at 7 years. In contrast, 10% of patients in whom previous treatment had failed were pain-free. When needed, salvage therapy with repeat GKRS, microvascular decompression, or percutaneous lesioning was successful in 70%. Posttreatment facial numbness was reported as very bothersome in 5%, most commonly in patients who underwent another invasive treatment. After GKRS, 73% reported that trigeminal neuralgia had no impact on their quality of life.
GKRS is a reasonable long-term treatment option for patients with typical trigeminal neuralgia. It yields durable pain control in a majority of patients, as well as improved quality of life with limited complications and it does not significantly affect the efficacy of other surgical treatments, should they be needed.
Neurosurgery 12/2008; 63(5):915-23; discussion 923-4. · 2.79 Impact Factor
