J. Michael Fitzpatrick

J. Michael Fitzpatrick
Vanderbilt University | Vander Bilt · Department of Electrical Engineering and Computer Science

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197
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11,664
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Publications

Publications (197)
Article
Objective: Minimally invasive, image-guided cochlear implantation (CI) surgery consists of drilling a precise tunnel from the surface of the mastoid cortex through the facial recess to target the scala tympani. In the first set of clinical trials of this technique, heat-induced facial nerve paresis (House-Brackmann II/VI) occurred on a patient on...
Article
Background: When robots mill bone near critical structures, safety margins are used to reduce the risk of accidental damage due to inaccurate registration. These margins are typically set heuristically with uniform thickness, which does not reflect the anisotropy and spatial variance of registration error. Methods: A method is described to gener...
Conference Paper
Safe and effective planning for robotic surgery that involves cutting or ablation of tissue must consider all potential sources of error when determining how close the tool may come to vital anatomy. A pre-operative plan that does not adequately consider potential deviations from ideal system behavior may lead to patient injury. Conversely, a plan...
Article
Robots have been shown to be useful in assisting surgeons in a variety of bone drilling and milling procedures. Examples include commercial systems for joint repair or replacement surgeries, with in vitro feasibility recently shown for mastoidectomy. Typically, the robot is guided along a path planned on a CT image that has been registered to the p...
Conference Paper
Today, the phrase, “Target Registration Error”, typically shortened to TRE, is an integral part of the vernacular of both surgical guidance and image registration, but it was not always so. This terminology, along with “Fiducial Registration Error” and “Fiducial Localization Error” was developed circa 1990 to facilitate the communication of informa...
Article
Otologic surgery often involves a mastoidectomy, which is the removal of a portion of the mastoid region of the temporal bone, to safely access the middle and inner ear. The surgery is challenging because many critical structures are embedded within the bone, making them difficult to see and requiring a high level of accuracy with the surgical diss...
Patent
Full-text available
A method and apparatus of percutaneous cochlear implantation (PCI). In one embodiment, the method includes the steps of (a) implanting a plurality of anchor members in a skull of a patient surrounding an ear of the patient, (b) attaching a docking frame to the plurality of anchor members, wherein the docking frame has a docking platform and a plura...
Article
Objectives/hypothesis: Minimally invasive image-guided approach to cochlear implantation (CI) involves drilling a narrow, linear tunnel to the cochlea. Reported herein is the first clinical implementation of this approach. Study design: Prospective cohort study. Methods: On preoperative computed tomography (CT), a safe linear trajectory throug...
Patent
Full-text available
The present invention, in another aspect, relates to a microstereotactic table. In one embodiment, the microstereotactic table includes a plate member having a first surface, an opposite, second surface, a body portion defined therebetween, a plurality of leg members, each of them removably engaged with the plate member, respectively, and a passage...
Article
Otologic surgery often involves a mastoidectomy procedure, in which part of the temporal bone is milled away in order to visualize critical structures embedded in the bone and safely access the middle and inner ear. We propose to automate this portion of the surgery using a compact, bone-attached milling robot. A high level of accuracy is required...
Conference Paper
In recent years, bone-attached robots and microstereotactic frames have attracted increasing interest due to the promising targeting accuracy they provide. Such devices attach to a patient's skull via bone anchors, which are used as landmarks during intervention planning as well. However, as simulation results reveal, the performance of such mechan...
Conference Paper
In 1996 Freeborough proposed a method for estimating target registration error (TRE) in the absence of ground truth. In his approach, a circuit of registrations is performed using the same registration method on multiple views of the same object: 1 to 2, 2 to 3, …, Nc –1 to Nc , and Nc to 1 where Nc is at least three and the last registration compl...
Article
Full-text available
Deep brain stimulation (DBS) surgery utilizes image guidance via bone-implanted fiducial markers to achieve the desired submillimetric accuracy and to provide means for attaching microstereotactic frames. For maximal benefit, the markers must be inserted to the correct depth since over-insertion leads to stripping and under-insertion leads to insta...
Article
Minimally invasive image-guided cochlear implantation (CI) involves accessing the cochlea via a linear path from the lateral skull to the cochlea avoiding vital structures including the facial nerve. Herein, we describe and demonstrate the feasibility of the technique for pediatric patients. Prospective. Children's Hospital. Thirteen pediatric pati...
Patent
Full-text available
Systems and methods for performing computer-assisted procedures are provided. In the systems and methods, a current rigid transformation is applied to a first set of points with respect to a second set of points to obtain a current transformed set of points. Thereafter, a linearized transformation is determined that minimizes a weighted fiducial re...
Article
Background: Registered medical images can assist with surgical navigation and enable image-guided therapy delivery. In soft tissues, surface-based registration is often used and can be facilitated by laser surface scanning. Tracked conoscopic holography (which provides distance measurements) has been recently proposed as a minimally invasive way t...
Article
Purpose: Validation of a novel minimally invasive, image-guided approach to implant electrodes from three FDA-approved manufacturers-Medel, Cochlear, and Advanced Bionics-in the cochlea via a linear tunnel from the lateral cranium through the facial recess to the cochlea. Methods: Custom microstereotactic frames that mount on bone-implanted fidu...
Patent
In one aspect, an apparatus for supporting an adjustable surgical platform is disclosed. In one embodiment, the apparatus includes a supporting platform portion with a body portion that defines bore along a central axis. Arm portions with engaging means extend radially from the supporting platform portion. The apparatus also includes a shaft portio...
Article
Stereotactic frames are a standard tool for neurosurgical targeting, but are uncomfortable for patients and obstruct the surgical field. Microstereotactic frames are more comfortable for patients, provide better access to the surgical site, and have grown in popularity as an alternative to traditional stereotactic devices. However, clinically avail...
Patent
Full-text available
A system and methods for providing an access to a cochlea of a living subject. In one embodiment of the present invention, a method comprises the steps of operating a surgical instrument towards a region of interest of the living subject for opening an access to the cochlea of the living subject from the lateral edge of the skull of the living subj...
Patent
Full-text available
In another aspect, the present invention relates to a method for determining the position and orientation of an anchor attached to the skull of a patient from a topographic image of the anchor acquired therefrom. In one embodiment, the method includes the steps of simulating an image of the anchor that matches the acquired topographic image of the...
Article
Probe guides are surgical fixtures that are rigidly attached to bone anchors in order to place a probe at a target with high accuracy (RMS error < 1 mm). Applications include needle biopsy, the placement of electrodes for deep-brain stimulation (DBS), spine surgery, and cochlear implant surgery. Targeting is based on pre-operative images, but targe...
Article
During endoscopic procedures it is often desirable to determine the distance between anatomical features. One such clinical application is percutaneous cochlear implantation (PCI), which is a minimally invasive approach to the cochlea via a single, straight drill path and can be achieved accurately using bone-implanted markers and customized micros...
Article
Full-text available
Since its introduction in the early 1990s, the Iterative Closest Point (ICP) algorithm has become one of the most well-known methods for geometric alignment of 3D models. Given two roughly aligned shapes represented by two point sets, the algorithm iteratively establishes point correspondences given the current alignment of the data and computes a...
Article
Presents the revised text for two paragraphs from the above titled paper (ibid., vol. 30, no. 3, pp. 679-693, Mar. 2011).
Article
Full-text available
Portable CT scanners are beneficial for diagnosis in the intensive care unit, emergency room, and operating room. Portable fixed-base versus translating-base CT systems were evaluated for otologic image-guided surgical (IGS) applications based on geometric accuracy and utility for percutaneous cochlear implantation. Five cadaveric skulls were fitte...
Article
Impact factor (IF) consists of reporting the number of references an average article in a given journal receives over a 2-year period. Despite several valid criticisms, IF has become an important component of academic advancement. The authors sought to investigate the possible relationship between size of specialty field and IF. The top 10 journals...
Article
Full-text available
Cochlear implantation is a surgical procedure for treating patients with hearing loss in which an electrode array is inserted into the cochlea. The traditional surgical approach requires drilling away a large portion of the bone behind the ear to provide anatomical reference and access to the cochlea. A minimally-invasive technique, called percutan...
Article
The Iterative Closest Point (ICP) algorithm is a widely used method for geometric alignment of 3D models. Given two roughly aligned shapes represented by two point sets, the algorithm iteratively establishes point correspondences given the current alignment of the data and computes a rigid transformation accordingly. It can be shown that the method...
Article
A general approach to the first-order analysis of error in rigid point registration is presented that accommodates fiducial localization error (FLE) that may be inhomogeneous (varying from point to point) and anisotropic (varying with direction) and also accommodates arbitrary weighting that may also be inhomogeneous and anisotropic. Covariances ar...
Article
Using image-guided surgical techniques, we propose that an industrial robot can be programmed to safely, effectively, and efficiently perform a mastoidectomy. Whereas robotics is a mature field in many surgical applications, robots have yet to be clinically used in otologic surgery despite significant advantages including reliability and precision....
Conference Paper
Full-text available
Time-of-Flight (ToF) sensors have become a considerable alternative to conventional surface acquisition techniques such as laser range scanning and stereo vision. Application of ToF cameras for the purpose of intra-operative registration requires matching of the noisy surfaces generated from ToF range data onto pre-interventionally acquired high-re...
Conference Paper
Image-guided surgery systems have a wide range of applications where the level of accuracy required for each application varies from millimeters to low sub-millimeter range. In systems that use optical tracking, it is typical to use point-based registration without any weighting schemes to determine the pose of the tracked tool with very good accur...
Article
Cochlear implantation is a surgical procedure in which an electrode array is permanently implanted into the cochlea to stimulate the auditory nerve and allow deaf people to hear. Percutaneous cochlear access, a new minimally invasive implantation approach, requires drilling a single linear channel from the skull surface to the cochlea. The focus of...
Article
Microstereotactic frames are a subset of stereotactic frames. They are smaller than traditional frames, and they employ small discrete anchors that are screwed into a patient's bony anatomy, typically the skull. These anchors provide points of attachment for the frame and also serve as markers that provide a bridge between image space and physical...
Article
Registration is presented as the central issue of surgical guidance. The focus is on the accuracy of approaches employed today, all of which use pre-operative images to guide surgery on rigid anatomy. The three most well-established approaches to guidance, namely the stereotactic frame, point fiducials, and surface matching, are examined in detail,...
Article
Full-text available
Deep-brain stimulation (DBS) surgery involves placing electrodes within specific deep-brain target nuclei. Surgeons employ MR imaging for preoperative selection of targets and computed tomography (CT) imaging for designing stereotactic frames used for intraoperative placement of electrodes at the targets. MR distortion may contribute to target-sele...
Article
A method for the first-order analysis of the point registration problem is presented and validated. The method is a unified approach to the problem that allows for inhomogeneous and anisotropic fiducial localization error (FLE) and arbitrary weighting in the registration algorithm. Cross-covariance matrices are derived both for target registration...
Article
Full-text available
Previous studies have evaluated the accuracy of several approaches for the placement of electrodes for deep brain stimulation. In this paper, we present a strategy to minimize the effect of brain shift on the estimation of the electrode placement error (EPE) for a stereotactic platform in the absence of intraoperative imaging data, and we apply it...
Article
Percutaneous cochlear implantation (PCI) surgery uses patient-specific customized microstereotactic frames to achieve a single drill-pass from the lateral skull to the cochlea, avoiding vital anatomy. We demonstrate the use of a specific microstereotactic frame, called a "microtable," to perform PCI surgery on cadaveric temporal bone specimens. Fea...
Article
Percutaneous cochlear implant (PCI) surgery consists of drilling a single trough from the lateral cranium to the cochlea avoiding vital anatomy. To accomplish PCI, we use a patient-customized microstereotactic frame, which we call a "microtable" because it consists of a small tabletop sitting on legs. The orientation of the legs controls the alignm...
Article
Time-of-Flight (ToF) sensors have become a considerable alternative to conventional surface acquisition techniques such as laser range scanning and stereo vision. Application of ToF cameras for the purpose of intra-operative registration requires matching of the noisy surfaces generated from ToF range data onto pre-interventionally acquired high-re...
Article
To introduce a novel microstereotactic frame, called the Microtable, consisting of a tabletop that mounts on bone-implanted spherical markers. The microtable is customized for individual patient anatomy to guide a surgical instrument to a specified target. Fiducial markers are bone-implanted, and CT scanning is performed. A microtable is custom-des...
Article
Rigid-body, point-based registration is commonly used for image-guided systems. Fiducial markers that can be localized in image and physical space are attached to patient anatomy. The fiducial marker locations in the two spaces are used to obtain the physical-to-image registration. It is a common practice to obtain physical positions via optical sy...
Article
Full-text available
Deep-brain-stimulation (DBS) surgery requires implanting stimulators at target positions with submillimetric accuracy. Traditional stereotactic frames can provide such accuracy, but a recent innovation called the microTargeting Platform (FHC, Inc.) replaces this large, universal frame with a single-use, miniature, and custom-designed platform. Both...
Article
Full-text available
Applying image-guidance to an electronically-controlled surgical drill can prevent damage to patients' anatomy during resection. A system is presented that disables the drill when it nears pre-defined critical patient anatomy. The system consists of a tracking system, image-guidance software, and drill-control circuit. The software was developed in...
Article
Image-guidance systems based on fiducial registration typically display some measure of registration accuracy based on the goodness of fit of the fiducials. A common measure is fiducial registration error (FRE), which equals the root-meansquare error in fiducial alignment between image space and physical space. It is natural for the surgeon to rega...
Article
Image-guided surgical (IGS) technology has been clinically available for more than a decade. To date, no acceptable standard exists for reporting the accuracy of IGS systems, especially for lateral skull base applications. We present a validation method that uses the post from bone-anchored hearing aid (BAHA) patients as a target. We then compare t...
Article
PurposeTo identify and quantify structural changes in the maturing brain between childhood and adolescence.Materials and Methods Two three-dimensional T1-weighted MR volumes of the brain were acquired from eight subjects, 6 to 7 years apart. The subjects were 9 to 12 years old on the first scan and 15 to 19 years old on the second scan. The MR scan...
Article
Suppose we have measured £ corresponding points in a pair of ¤-dimensional images, and want to compute a similarity transform relating them. Such a situation occurs for example in Image-guided Surgery, where very accurate alignments are required, and attained through the use of markers, or ultrasound calibrations [4] 1. A similarity transform combi...
Article
Percutaneous cochlear implant surgery consists of a single drill path from the lateral mastoid cortex to the cochlea via the facial recess. We sought to clinically validate this technique in patients undergoing traditional cochlear implant surgery. Prospective clinical trial. After institutional regulatory board-approved protocols, five ears were s...
Article
One method used to correct geometric and intensity distortions in echo planar images is to register them to undistorted images via nonrigid deformations. However, some areas in the echo planar images are more distorted than others, thus suggesting the use of deformations whose characteristics are adapted spatially. In this article, we incorporate i...
Article
Many image-guidance surgical systems rely on rigid-body, point-based registration of fiducial markers attached to the patient. Marker locations in image space and physical space are used to provide the transformation that maps a point from one space to the other. Target registration error (TRE) is known to depend on the fiducial localization error...
Article
Gradient-echo (GE) echo planar imaging (EPI) is susceptible to both geometric distortions and signal loss. This paper presents a retrospective correction approach based on nonrigid image registration. A new physics-based intensity correction factor derived to compensate for intravoxel dephasing in GE EPI images is incorporated into a previously rep...
Article
As an extension of previous work on computer-generated phantoms, more accurate, realistic phantoms are generated by integrating image distortion and signal loss caused by susceptibility variations. With the addition of real motions and activations determined from actual functional MRI studies, these phantoms can be used by the fMRI community to ass...
Article
Image registrations that are based on similarity measures simply adjust the parameters of an appropriate spatial transformation model until the similarity measure reaches an optimum. The numerous similarity measures that have been proposed in the past are differently sensitive to imaging modality, image content and differences in the image content,...
Article
To date, clinical application of image-guided surgery (IGS) to otology/neurotology has been limited, but a large potential market and numerous applications support use. Such applications include control of surgical instruments (eg, turning off a drill when close to an anatomic boundary), robotic surgery (eg, robotic mastoidectomy), and minimally in...
Article
Percutaneous cochlear access can be performed using bone-mounted drill guides that are custom made on the basis of preintervention computed tomographic scans. We have previously demonstrated the ability to use image guidance based on fiducial markers to obtain percutaneous cochlear access in vitro. A simpler approach that has far less room for appl...
Article
Image guidance in otologic surgery has been thwarted by the need for a non-invasive fiducial system with target registration error (TRE) at the inner ear below 1.5mm. We previously presented a fiducial frame for this purpose that attaches to the upper dentition via patient-specific bite blocks and demonstrated a TRE of 0.73mm (±0.23mm) on cadaveric...
Article
Echo planar images (EPI) suffer from geometric distortions caused by static-field inhomogeneity. Correction techniques have been suggested based on field maps obtained before or after the EPI acquisition. However, when a relatively long time series of images is required, as in fMRI studies, the inhomogeneity varies from image to image because of gr...
Article
In cochlear implant surgery an electrode array is permanently implanted to stimulate the auditory nerve and allow deaf people to hear. Current surgical techniques require wide excavation of the mastoid region of the temporal bone and one to three hours time to avoid damage to vital structures. Recently a far less invasive approach has been proposed...
Article
Full-text available
The procedure currently used for cochlear implementation requires wide surgical exposure to identify anatomic landmarks. At our institution a minimally invasive technique is being developed that will permit to perform the procedure with a small burr hole. This technique does, however, require identifying pre-operatively a surgical path that reaches...
Article
HYPOTHESIS:: Percutaneous cochlear access can be performed using bone-mounted drill guides that are custom made on the basis of preintervention computed tomographic scans. BACKGROUND:: We have previously demonstrated the ability to use image guidance based on fiducial markers to obtain percutaneous cochlear access in vitro. A simpler approach that...
Conference Paper
Surgery for deep-brain simulation (DBS) requires implanting of stimulators at target positions with submillimetric accuracy, typically via stereotactic frames. A recent innovation replaces the large, universal frame with a miniature frame customized per patient. We present a method for evaluating the accuracy of these new frames using "virtual targ...
Article
It has been recently proposed that computer-simulated phantom images can be used to evaluate methods for fMRI preprocessing. It is widely recognized that Gradient-Echo Echo Planar Imaging (EPI), the most often used technique for fMRI, is strongly affected by field inhomogeneities. Accurate and realistic phantom images for use by the fMRI community...
Article
Geometric distortion is a well-recognized problem in echo planar (EP) images. One strategy for the correction of these distortions is to register an EP image to a reference image, such as a high resolution anatomical MR image in which geometric distortion is minimal. Non-rigid registration methods, which warp images locally, have been used for this...
Conference Paper
Image-guided otologic surgeries performed on healthy patients require non-invasive fiducial systems that achieve submillimetric target registration error (TRE). We have described such a system that attaches repeatably to a subject via a dental bite block. We now describe a new method for the clinical validation of such a system that can be conducte...
Article
Image-guided surgery will permit accurate access to the middle ear via the facial recess using a single drill hole from the lateral aspect of the mastoid cortex. The widespread use of image-guided methods in otologic surgery has been limited by the need for a system that achieves the necessary level of accuracy with an easy-to-use, noninvasive fidu...
Article
An algorithm is presented that is designed for image-guidance systems that employ coordinate reference frames. It is common in image-guided surgery (IGS) to use a tracking system to determine the position of fiducial markers in physical space. Typically a "Coordinate Reference Frame" (CRF), is also employed, which is rigidly attached to the object...
Article
Full-text available
Application of image-guided surgery to otology has been limited by the need for submillimeter accuracy via a fiducial system that is easily usable (noninvasive and nonobstructive). A dental bite-block was fitted with a rigid frame with 7 fiducial markers surrounding each external ear. The temporal bones of 3 cadaveric skulls were removed and replac...
Article
Use of image-guided surgery (IGS) systems in otolaryngology, particularly rhinology, has grown exponentially in recent years. Central to their use is the understanding of the accuracy of each system. The purpose of this review is to discuss the error inherent in all IGS systems. A standardized technique (currently used in the engineering literature...
Article
Full-text available
In this study, a new system was evaluated for implanting deep-brain stimulators based on a one-piece platform for each trajectory customized from a preoperative planning image. During surgery, the platform is attached to skull-implanted posts that extend through the scalp. The platform acts as a miniature stereotactic frame to provide guidance for...
Article
Robust and accurate segmentation methods are important for the computerized evaluation of medical images. For treatment of rheumatoid arthritis, joint damage assessment in radiographs of hands is frequently used for monitoring disease progression. Current clinical scoring methods are based on visual measurements that are time-consuming and subject...
Article
Image registration is an important procedure for medical diagnosis. Since the large inter-site retrospective validation study led by Fitzpatrick at Vanderbilt University, voxel-based methods and more specifically mutual information-based registration methods (see for instance [IEEE Trans. Med. Imag. 22 (8) (2003) 986] for a review on these methods)...
Conference Paper
Otologic surgery is undertaken to treat ailments of the ear including persistent infections, hearing loss, vertigo, and cancer. Typically performed on healthy patients in outpatient facilities, the application of image-guided surgery has been limited because accurate (<1mm), non-invasive fiducial systems for otologic surgery are not available. We h...