Faculty Bibliography

Primary spinal primitive neuroectodermal tumors (PNETs) are uncommon malignancies that are increasingly reported in the literature. Spinal PNETs, like their cranial counterparts, are aggressive tumors and patients with these tumors typically have short survival times despite maximal surgery, chemotherapy, and radiation. Because no standard management guidelines exist for treating these tumors, a multitude of therapeutic strategies have been employed with varying success. In this study the authors perform a comprehensive review of the literature on primary spinal PNETs and provide 2 new cases that highlight the salient features of their clinical management.

BACKGROUND:Computer-based surgical simulators create a no-risk virtual environment where surgeons can develop and refine skills through harmless repetition. These applications may be of particular benefit to neurosurgeons, as the vulnerability of nervous tissue limits the margin for error. The rapid progression of computer-processing capabilities in recent years has led to the development of more sophisticated and realistic neurosurgery simulators. OBJECTIVE:To catalogue the most salient of these advances and characterize our current effort to create a spine surgery simulator. METHODS:An extensive search of the databases Ovid-MEDLINE, PubMed, and Google Scholar was conducted. Search terms included, but were not limited to: neurosurgery combined with simulation, virtual reality, haptics, and 3-dimensional imaging. RESULTS:A survey of the literature reveals that surgical simulators are evolving from platforms used for preoperative planning and anatomic education into programs that aim to simulate essential components of key neurosurgical procedures. This evolution is predicated upon the advancement of 3 main components of simulation: graphics/volume rendering, model behavior/tissue deformation, and haptic feedback. CONCLUSION/CONCLUSIONS:The computational burden created by the integration of these complex components often limits the fluidity of real-time interactive simulators. Although haptic interfaces have become increasingly sophisticated, the production of realistic tactile sensory feedback remains a formidable and costly challenge. The rate of future progress may be contingent upon international collaboration between research groups and the establishment of common simulation platforms. Given current limitations, the most potential for growth lies in the innovative design of models that expand the procedural applications of neurosurgery simulation environments.

OBJECT/OBJECTIVE:The objective of this systematic review was to use evidence-based medicine to identify the best methodology for diagnosis and treatment of anterior pseudarthrosis. METHODS:The National Library of Medicine and Cochrane Database were queried using MeSH headings and key words relevant to pseudarthrosis and cervical spine surgery. Abstracts were reviewed, after which studies meeting inclusion criteria were selected. The guidelines group assembled an evidentiary table summarizing the quality of evidence (Classes I-III). Disagreements regarding the level of evidence were resolved through an expert consensus conference. The group formulated recommendations that contained the degree of strength based on the Scottish Intercollegiate Guidelines network. Validation was done through peer review by the Joint Guidelines Committee of the American Association of Neurological Surgeons/Congress of Neurological Surgeons. RESULTS:Evaluation for pseudarthrosis is warranted, as there may be an association between clinical outcome and pseudarthrosis. The strength of this association cannot be accurately determined because of the variable incidence of symptomatic and asymptomatic pseudarthroses (Class III). Revision of a symptomatic pseudarthrosis may be considered because arthrodesis is associated with improved clinical outcome (Class III). Both posterior and anterior approaches have proven successful for surgical correction of an anterior pseudarthrosis. Posterior approaches may be associated with higher fusion rates following repair of an anterior pseudarthrosis (Class III). CONCLUSIONS:If suspected, pseudarthrosis should be investigated because there may be an association between arthrodesis and outcome. However, the strength of this association cannot be accurately determined. Anterior and posterior approaches have been successful.

OBJECT/OBJECTIVE:The objective of this systematic review was to use evidence-based medicine to examine the diagnostic and therapeutic utility of intraoperative electrophysiological (EP) monitoring in the surgical treatment of cervical degenerative disease. METHODS:The National Library of Medicine and Cochrane Database were queried using MeSH headings and key words relevant to cervical spine surgery and EP monitoring. The guidelines group assembled an evidentiary table summarizing the quality of evidence (Classes I-III). The group formulated recommendations that contained the degree of strength based on the Scottish Intercollegiate Guidelines network. Validation was done through peer review by the Joint Guidelines Committee of the American Association of Neurological Surgeons/Congress of Neurological Surgeons. RESULTS:The reliance on changes in EP monitoring as an indication to alter a surgical plan or administer steroids has not been observed to reduce the incidence of neurological injury during routine surgery for cervical spondylotic myelopathy or cervical radiculopathy (Class III). However, there is an absence of study data examining the benefit of altering a surgical plan due to EP changes. CONCLUSIONS:Although the use of EP monitoring may serve as a sensitive means to diagnose potential neurological injury during anterior spinal surgery for cervical spondylotic myelopathy, the practitioner must understand that intraoperative EP worsening is not specific-it may not represent clinical worsening and its recognition does not necessarily prevent neurological injury, nor does it result in improved outcome (Class II). Intraoperative improvement in EP parameters/indices does not appear to forecast outcome with reliability (conflicting Class I data).

In March 2006, the Joint Section on Disorders of the Spine and Peripheral Nerves of the American Association of Neurological Surgeons and Congress of Neurological Surgeons compiled an expert group to perform an evidence-based review of the clinical literature on management of cervical degenerative spine disease. This process culminated in the formation of the Guidelines for the Surgical Management of Cervical Degenerative Disease. The purpose of the Guidelines was to address questions regarding the therapy, diagnosis, and prognosis of cervical degenerative disease using an evidence-based approach. Development of an evidence-based review and recommendations is a multitiered process. Typical guideline development consists of 5 processes: 1) collection and selection of the evidence; 2) assessment of the quality and strength of the evidence; 3) analysis of the evidentiary data; 4) formulation of recommendations; and 5) guideline validation. This manuscript details the methodology in compiling the Guidelines for the Surgical Management of Cervical Degenerative Disease.

OBJECT/OBJECTIVE:The objective of this systematic review was to use evidence-based medicine to delineate the natural history of cervical spondylotic myelopathy (CSM) and identify factors associated with clinical deterioration. METHODS:The National Library of Medicine and Cochrane Database were queried using MeSH headings and keywords relevant to the natural history of CSM. Abstracts were reviewed and studies meeting the inclusion criteria were selected. The guidelines group assembled an evidentiary table summarizing the quality of evidence (Classes I-III). Disagreements regarding the level of evidence were resolved through an expert consensus conference. The group formulated recommendations that contained the degree of strength based on the Scottish Intercollegiate Guidelines network. Validation was done through peer review by the Joint Guidelines Committee of the American Association of Neurological Surgeons and the Congress of Neurological Surgeons. RESULTS:The natural history of CSM is mixed: it may manifest as a slow, stepwise decline or there may be a long period of quiescence (Class III). Long periods of severe stenosis are associated with demyelination and may result in necrosis of both gray and white matter. With severe and/or long lasting CSM symptoms, the likelihood of improvement with nonoperative measures is low. Objectively measurable deterioration is rarely seen acutely in patients younger than 75 years of age with mild CSM (modified Japanese Orthopaedic Association scale score > 12; Class I). In patients with cervical stenosis without myelopathy, the presence of abnormal electromyography findings or the presence of clinical radiculopathy is associated with the development of symptomatic CSM in this patient population (Class I). CONCLUSIONS:The natural history of CSM is variable, which may affect treatment decisions.

OBJECT/OBJECTIVE:The objective of this systematic review was to use evidence-based medicine to assess whether clinical factors predict surgical outcomes in patients undergoing cervical surgery. METHODS:The National Library of Medicine and Cochrane Database were queried using MeSH headings and keywords relevant to clinical preoperative factors. Abstracts were reviewed, and studies that met the inclusion criteria were selected. The guidelines group assembled an evidentiary table summarizing the quality of evidence (Classes I-III). Disagreements regarding the level of evidence were resolved through an expert consensus conference. The group formulated recommendations that contained the degree of strength based on the Scottish Intercollegiate Guidelines network. Validation was done through peer review by the Joint Guidelines Committee of the American Association of Neurological Surgeons/Congress of Neurological Surgeons. RESULTS:Preoperative sensory-evoked potentials may aid in providing prognostic information in selected patients in whom clinical factors do not provide clear guidance (Class II). Age, duration of symptoms, and preoperative neurological function may commonly affect outcome (Class III). CONCLUSIONS:Age, duration of symptoms, and preoperative neurological function should be discussed with patients when surgical intervention for cervical spondylotic myelopathy is considered. Preoperative sensory-evoked potentials may be considered for patients in whom clinical factors do not provide clear guidance if such information would potentially change therapeutic decisions.