The microneurosurgical anatomy legacy of Albert L. Rhoton Jr., MD: an analysis of transition and evolution over 50 years.

The authors chronologically categorized the 160 original articles written by Dr. Rhoton and his fellows to show why they selected their themes and how they carried out their projects. The authors note that as neurosurgery progresses and new techniques and approaches are developed, accurate and safe treatment will depend upon continued clarification of microsurgical anatomy.

Variations of Occipital Artery-Posterior Inferior Cerebellar Artery Bypass: Anatomic Consideration.

BACKGROUND: Advances in diagnosis of posterior inferior cerebellar artery (PICA) aneurysms have revealed the high frequency of distal and/or dissecting PICA aneurysms. Surgical treatment of such aneurysms often requires revascularization of the PICA including but not limited to its caudal loop. OBJECTIVE: To examine the microsurgical anatomy involved in occipital artery (OA)-PICA anastomosis at various anatomic segments of the PICA. METHODS: Twenty-eight PICAs in 15 cadaveric heads were examined with the operating microscope to take morphometric measurements and explore the specific anatomy of bypass procedures. RESULTS: OA bypass to the p2, p3, p4, or p5 segment was feasible with a recipient vessel of sufficient diameter. The loop wandering near the jugular foramen in the p2 segment provided sufficient length without requiring cauterization of any perforating arteries to the brainstem. Wide dissection of the cerebellomedullary fissure provided sufficient exposure for the examination of some p3 segments and all p4 segments hidden by the tonsil. OA-p5 bypass was placed at the main trunk before the bifurcation in 5 hemispheres and at the larger hemispheric trunk in others. CONCLUSION: Understanding the possible variations of OA-PICA bypass may enable revascularization of the appropriate portion of the PICA when the parent artery must be occluded. A detailed anatomic understanding of each segment clarifies important technical nuances for the bypass on each segment. Dissection of the cerebellomedullary fissure helps to achieve sufficient exposure for the bypass procedures on most of the segments.

Mixed reality ventriculostomy simulation: experience in neurosurgical residency.

BACKGROUND: Medicine and surgery are turning toward simulation to improve on limited patient interaction during residency training. Many simulators today use virtual reality with augmented haptic feedback with little to no physical elements. In a collaborative effort, the University of Florida Department of Neurosurgery and the Center for Safety, Simulation & Advanced Learning Technologies created a novel "mixed" physical and virtual simulator to mimic the ventriculostomy procedure. The simulator contains all the physical components encountered for the procedure with superimposed 3-D virtual elements for the neuroanatomical structures. OBJECTIVE: To introduce the ventriculostomy simulator and its validation as a necessary training tool in neurosurgical residency. METHODS: We tested the simulator in more than 260 residents. An algorithm combining time and accuracy was used to grade performance. Voluntary postperformance surveys were used to evaluate the experience. RESULTS: Results demonstrate that more experienced residents have statistically significant better scores and completed the procedure in less time than inexperienced residents. Survey results revealed that most residents agreed that practice on the simulator would help with future ventriculostomies. CONCLUSION: This mixed reality simulator provides a real-life experience, and will be an instrumental tool in training the next generation of neurosurgeons. We have now implemented a standard where incoming residents must prove efficiency and skill on the simulator before their first interaction with a patient.

Mixed-reality simulation for neurosurgical procedures.

BACKGROUND: Surgical education is moving rapidly to the use of simulation for technical training of residents and maintenance or upgrading of surgical skills in clinical practice. To optimize the learning exercise, it is essential that both visual and haptic cues are presented to best present a real-world experience. Many systems attempt to achieve this goal through a total virtual interface. OBJECTIVE: To demonstrate that the most critical aspect in optimizing a simulation experience is to provide the visual and haptic cues, allowing the training to fully mimic the real-world environment. METHODS: Our approach has been to create a mixed-reality system consisting of a physical and a virtual component. A physical model of the head or spine is created with a 3-dimensional printer using deidentified patient data. The model is linked to a virtual radiographic system or an image guidance platform. A variety of surgical challenges can be presented in which the trainee must use the same anatomic and radiographic references required during actual surgical procedures. RESULTS: Using the aforementioned techniques, we have created simulators for ventriculostomy, percutaneous stereotactic lesion procedure for trigeminal neuralgia, and spinal instrumentation. The design and implementation of these platforms are presented. CONCLUSION: The system has provided the residents an opportunity to understand and appreciate the complex 3-dimensional anatomy of the 3 neurosurgical procedures simulated. The systems have also provided an opportunity to break procedures down into critical segments, allowing the user to concentrate on specific areas of deficiency.

The central nervous system solitary fibrous tumor: a review of clinical, imaging and pathologic findings among all reported cases from 1996 to 2010.

OBJECTIVE: Central nervous system (CNS) solitary fibrous tumor (SFT) is a rare lesion first identified as a unique entity in 1996. We describe two cases treated at the University of Florida followed by a review of all reported cases of CNS SFT between 1996 and 2010. METHODS: A review of the literature was performed to identify all reported cases of CNS SFT. RESULTS: 189 cases (including the two presented herein) were discovered, of which 46 were spinal and 143 were intracranial. Demographic, imaging, and pathologic findings are presented. Roughly 6% of reported lesions are malignant. Subtotal resection (STR) was associated with a 16-fold increased odds of recurrence (OR 15.9, 95% CI 5.5-46.1), although mean follow-up was shorter in those cases of GTR without recurrence. CONCLUSION: CNS SFT is a rare lesion. Six percent of lesions are malignant. GTR is superior to STR although the degree of superiority is not clear.

Evaluation of a transition to practice program for neurosurgery residents: creating a safe transition from resident to independent practitioner.

BACKGROUND: In 2004, the Department of Neurosurgery at the University of Florida implemented a major curriculum innovation called the Transition to Practice program. This program was established to prepare residents to more safely transition to the role of independent practitioner. METHODS: A qualitative and quantitative evaluation of the program was conducted after its fifth year using online surveys and interviews. Study participants included Transition to Practice graduates, faculty, and current residents. RESULTS: Of the 26 respondents, 89% of faculty and all graduates were very satisfied with the program. Strengths identified included an independent yet mentored broad operative experience, the development of self-confidence, and a real sense of responsibility for patients. Medical billing and coding instruction and career mentoring were areas of the program that required additional attention. CONCLUSION: Overall, this program is meeting the stated objectives and is well received by the graduates and faculty. Based on the results of this evaluation, curricular changes such as instructions in practice management and implementation of a career-mentoring program have occurred. The Transition to Practice program is a unique curricular response to change that other surgical specialties may find useful in addressing the current-day stresses on graduate medical education.

Cauda equina syndrome (CES) from lumbar disc herniations.

STUDY DESIGN: A retrospective review was performed to determine the outcomes of patients with cauda equina syndrome (CES) from a herniated lumbar disc at our institutions. OBJECTIVE: CES from lumbar herniated discs is considered the only absolute indication for surgery. It is considered a neurosurgical emergency with the outcome related to how quickly it is diagnosed and treated. The results of recovery of bladder function are felt by many authors to be related to early diagnosis and surgical intervention. Most authors recommend a wide decompressive laminectomy when surgery is performed. We reviewed our cases to determine if they conformed to these assumptions. SUMMARY OF BACKGROUND DATA: Although many articles regarding the outcome of CES from herniated lumbar discs suggest that early surgery is superior to surgery that is delayed, others have demonstrated no correlation between time-to-surgery and chances for recovery of neurologic and bladder function. METHODS: A retrospective review of all patients with lumbar herniated discs and CES from the years 1985 to 2004 was carried out. There were 31 patients, 28 of whom had bladder incontinence or retention requiring catheterization. Six patients were operated within 24 hours, 8 between 24 and 48 hours, and 17 after 48 hours (range: 60 h to 2 wk). Average follow-up was 5 years. RESULTS: Twenty-seven of these patients regained continence not requiring catheterization. There was no correlation between the time-to-surgery and recovery of bladder function. There was also no correlation between the time-to-surgery and recovery of motor and sensory function. The majority of patients underwent unilateral hemilaminotomy or bilateral hemilaminotomies; decompressive laminectomy was reserved for patients with underlying spinal stenosis or posteriorly herniated fragments. All of the patients were relieved of their radicular pain. CONCLUSIONS: In our series of patients with CES and bladder incontinence or retention, over 90% regained continence. Recovery of function was not related to the time to surgical intervention. The majority of the patients were adequately treated without the need for a complete laminectomy.