Effects of thigh extension on the position of the femoral nerve: application to prone lateral transpsoas approaches to the lumbar spine.

Some authors have suggested that thigh extension during the prone lateral transpsoas approach to the lumbar spine provides the theoretical advantage of providing posterior shift of the psoas muscle and plexus and is responsible for its lower rates of nerve injury. We aimed to elucidate the effects of surgical positioning on the femoral nerve within the psoas muscle via a cadaveric study. In the supine position, 10 fresh frozen adult cadavers had a metal wire secured to the pelvic segment of the femoral nerve and then extended proximally along with its L2 contribution. Fluoroscopy was then used to identify the wires on the femoral nerves in a neutral position and with the thigh extended and flexed by 25 and 45°. Additionally, a lateral incision was made in the anterolateral abdominal wall to mimic a lateral transpsoas approach to the lumbar spine, and measurements were made of the amount of movement in the vertical plane of the femoral nerve from neutral to then 25 and 45° of thigh flexion and extension. On fluoroscopy, the femoral nerves moved posteriorly at a mean of 10.1 mm with thigh extension. Femoral nerve movement could not be detected at any degree of this range of flexion of the thigh. Extension of the thigh to about 30° can move the femoral nerve farther away from the dissection plane by approximately one centimeter. This hip extension not only places the femoral nerve in a more advantageous position for lateral lumbar interbody fusion procedures but also helps to promote accentuation of lumbar lordosis.

Asymmetry of the C2 pars interarticularis: a clinical anatomical study with relevance to screw placement.

PURPOSE: Potential asymmetries of the C2 posterior elements pose a problem for the spine surgeon seeking to make the best choice for spinal stabilization while reducing morbidity. METHODS: A digital caliper was used to measure the pars interarticularis height and length on left and right sides of 25 adult C2 vertebrae. The pars interarticularis was defined as the bone between the posterior most aspect of the superior articular process and the anterior most aspect of the inferior articular process of C2. Also, the C2 vertebrae from 49 patients were scanned by CT. Parasagittal images were reviewed and using the same definitions as were used for the skeletal specimens, the length and the height of the C2 pars interarticularis from both the left and right sides were measured using CT. The image slices were acquired at 3 mm intervals. The pars interarticularis height was determined on sagittal CT reconstruction, while the pars interarticularis length was calculated on the basis of the axial images. RESULTS: The lengths and the heights of the left and right pars interarticularis were compared using CTs of patients and skeletal specimens. No significant differences were found in the length and height measurements of the CT images on both sides. However, in the skeletal specimens, the left and right pars interarticularis did not differ significantly in length but differed significantly in height (p = 0.003). The mean height of the left pars interarticularis was approximately two times larger than the right in the skeletal specimens. Absolute differences were calculated between the side with the greater length and height and the side with the lesser length and height irrespective of their left-right orientations. For CT measurements, most differences in length and height between the greater pars interarticularis and lesser pars interarticularis occurred between 0 and 1 mm with each successive disparity interval yielding lower numbers. Skeletal measurements revealed a similar length disparity distribution to the CT measurements. However, height measurements in the skeletal specimens varied widely. Eight pars interarticularis specimens demonstrated a height difference between 0 and 1 mm. No dry bone pars interarticularis specimens demonstrated a height difference between 1 and 2 mm. The pars interarticularis of nine specimens demonstrated a height difference between 2 and 3 mm. Two demonstrated a height difference between 3 and 4 mm. Four demonstrated a height difference between 4 and 5 mm and two demonstrated a height difference greater than 5 mm. The greater pars interarticularis lengths and heights were combined and compared to their lesser counterparts on CT and skeletal measurements. In all measurements of this type, significant differences were found in the pars interarticularis length and height, whether measured through CT or via digital calipers. CONCLUSION: Asymmetry between the left and right C2 pars interarticularis as shown in the present study can alter surgical planning. Therefore, knowledge of this anatomical finding might be useful to spine surgeons.

Does the L5 spinal nerve move? Anatomical evaluation with implications for postoperative L5 nerve palsy.

PURPOSE: While palsy of the L5 nerve root due to stretch injury is a known complication in complex lumbosacral spine surgery, the underlying pathophysiology remains unclear. The goal of this cadaveric study was to quantify movement of the L5 nerve root during flexion/extension of the hip and lower lumbar spine. METHODS: Five fresh-frozen human cadavers were dissected on both sides to expose the lumbar vertebral bodies and the L5 nerve roots. Movement of the L5 nerve root was tested during flexion and extension of the hip and lower lumbar spine. Four steps were undertaken to characterize these movements: (1) removal of the bilateral psoas muscles, (2) removal of the lumbar vertebral bodies including the transforaminal ligaments from L3 to L5, (3) opening and removing the dura mater laterally to visualize the rootlets, and (4) removal of remaining soft tissue surrounding the L5 nerve root. Two metal bars were inserted into the sacral body at the level of S1 as fixed landmarks. The tips of these bars were connected to make a line for the ruler that was used to measure movement of the L5 nerve roots. Movement was regarded as measurable when there was an L5 nerve excursion of at least 1 mm. RESULTS: The mean age at death was 86.6 years (range 68-89 years). None of the four steps revealed any measurable movement after flexion/extension of the hip and lower lumbar spine on either side (< 1 mm). Flexion of the hip and lower lumbar spine revealed lax L5 nerve roots. Extension of the hip and lower lumbar spine showed taut ones. CONCLUSION: Significant movement or displacement of the L5 nerve root could not be quantified in this study. No mechanical cause for L5 nerve palsy could be identified so the etiology of the condition remains unclear.

Operative and nonoperative adverse events in the management of traumatic fractures of the thoracolumbar spine: a systematic review.

OBJECT: Thoracolumbar spine injuries are commonly encountered in patients with trauma, accounting for almost 90% of all spinal fractures. Thoracolumbar burst fractures comprise a high percentage of these traumatic fractures (45%), and approximately half of the patients with this injury pattern are neurologically intact. However, a debate over complication rates associated with operative versus nonoperative management of various thoracolumbar fracture morphologies is ongoing, particularly concerning those patients presenting without a neurological deficit. METHODS: A MEDLINE search for pertinent literature published between 1966 and December 2013 was conducted by 2 authors (G.G. and R.D.), who used 2 broad search terms to maximize the initial pool of manuscripts for screening. These terms were "operative lumbar spine adverse events" and "nonoperative lumbar spine adverse events." RESULTS: In an advanced MEDLINE search of the term "operative lumbar spine adverse events" on January 8, 2014, 1459 results were obtained. In a search of "nonoperative lumbar spine adverse events," 150 results were obtained. After a review of all abstracts for relevance to traumatic thoracolumbar spinal injuries, 62 abstracts were reviewed for the "operative" group and 21 abstracts were reviewed for the "nonoperative" group. A total of 14 manuscripts that met inclusion criteria for the operative group and 5 manuscripts that met criteria for the nonoperative group were included. There were a total of 919 and 436 patients in the operative and nonoperative treatment groups, respectively. There were no statistically significant differences between the groups with respect to age, sex, and length of stay. The mean ages were 43.17 years in the operative and 34.68 years in the nonoperative groups. The majority of patients in both groups were Frankel Grade E (342 and 319 in operative and nonoperative groups, respectively). Among the studies that reported the data, the mean length of stay was 14 days in the operative group and 20.75 in the nonoperative group. The incidence of all complications in the operative and nonoperative groups was 300 (32.6%) and 21 (4.8%), respectively (p = 0.1065). There was no significant difference between the 2 groups with respect to the incidence of pulmonary, thromboembolic, cardiac, and gastrointestinal complications. However, the incidence of infections (pneumonia, urinary tract infection, wound infection, and sepsis) was significantly higher in the operative group (p = 0.000875). The incidence of instrumentation failure and need for revision surgery was 4.35% (40 of 919), a significant morbidity, and an event unique to the operative category (p = 0.00396). CONCLUSIONS: Due to the limited number of high-quality studies, conclusions related to complication rates of operative and nonoperative management of thoracolumbar traumatic injuries cannot be definitively made. Further prospective, randomized studies of operative versus nonoperative management of thoracolumbar and lumbar spine trauma, with standardized definitions of complications and matched patient cohorts, will aid in properly defining the risk-benefit ratio of surgery for thoracolumbar spine fractures.

Timing in the surgical evacuation of spinal epidural abscesses.

OBJECT: One often overlooked aspect of spinal epidural abscesses (SEAs) is the timing of surgical management. Limited evidence is available correlating earlier intervention with outcomes. Spinal epidural abscesses, once a rare diagnosis carrying a poor prognosis, are steadily becoming more common, with one recent inpatient meta-analysis citing an approximate incidence of 1 in 10,000 admissions with a mortality approaching 16%. One key issue of contention is the benefit of rapid surgical management of SEA to maximize outcomes. Timing of surgical management is definitely one overlooked aspect of care in spinal infections. Therefore, the authors performed a retrospective analysis in which they evaluated patients who underwent early (evacuation within 24 hours) versus delayed surgical intervention (> 24 hours) from the point of diagnosis, in an attempt to test the hypothesis that earlier surgery results in improved outcomes. METHODS: A retrospective review of a prospectively maintained adult neurosurgical database from 2009 to 2011 was conducted for patients with the diagnostic heading: epidural abscess, infection, osteomyelitis, osteodiscitis, spondylodiscitis, and abscess. The primary end point for each patient was neurological grade, measured as an American Spinal Injury Association Impairment Scale grade using hospital inpatient records on admission and discharge. Patients were divided into early surgical (< 24 hours) and delayed surgical cohorts. RESULTS: Eighty-seven consecutive patients were identified (25 females; mean age 55.5 years, age range 18-87 years). Fifty-four patients received surgery within 24 hours of admission (mean time from admission to incision, 11.2 hours), and 33 underwent surgery longer than 24 hours (mean 59 hours) after admission. Of the 54 patients undergoing early surgery 45 (85%) had a neurological deficit, whereas in the delayed surgical group 21 (64%) of 33 patients presented with a neurological deficit (p = 0.09). Patients in the delayed surgery cohort were significantly older by 10 years (59.6 vs 51.8 years, p = 0.01). With regard to history of prior revision, body mass index, intravenous drug abuse, tobacco use, prior radiation therapy, diabetes, chronic systemic infection, and prior osteomyelitis, there were no significant differences. There was no significant difference between early and delayed surgery groups in neurological grade on presentation, discharge, or location of epidural abscess. The most common organism isolated was Staphylococcus aureus (n = 51, 59.3%). The incidence of methicillin-resistant S. aureus was 21% (18 of 87). CONCLUSIONS: Evacuation within 24 hours appeared to have a relative advantage over delayed surgery with regard to discharge neurological grade. However, due to a limited, variable sample size, a significant benefit could not be shown. Further subgroup analyses with larger populations are required.

Patient-reported outcome measures in spine surgery: A systematic review.

Background: Steadily increasing expenditure in the United States health-care system has led to a shift toward a value-based model that focuses on quality of care and cost-effectiveness. Operations involving the spine rank among some of the most common and expensive procedures performed in operating rooms nationwide. Patient-reported outcomes measures (PROMs) are a useful tool for reporting levels of outcome and analyzing patient recovery but are both under-utilized and nonstandardized in spine surgery. Methods: We conducted a systematic review of the literature using the PubMed database, focusing on the most commonly utilized PROMs for spine disease as well as spinal deformity. The benefits and drawbacks of these PROMs were then summarized and compared. Results: Spine-specific PROMs were based on the class of disease. The most frequently utilized PROMs were the Neck Disability Index and the modified Japanese Orthopaedic Association scale; the Oswestry Disability Index and the Roland-Morris Disability Questionnaire; and the Scoliosis Research Society 22-item questionnaire (SRS-22) for cervicothoracic spine disease, lumbar spine disease, and spinal deformity, respectively. Conclusion: We found limited, though effective, use of PROMs targeting specific classes of disease within spine surgery. Therefore, we advocate for increased use of PROMs in spine surgery, in both the research and clinical settings. PROM usage can help physicians assess subjective outcomes in standard ways that can be compared across patients and institutions, more uniquely tailor treatment to individual patients, and engage patients in their own medical care.

Atlantoaxial instability secondary to Bartonella henselae osteomyelitis managed surgically by atlantoaxial instrumentation: A case report and systematic review.

Cat scratch disease (CSD), caused by Bartonella henselae, may atypically present with vertebral osteomyelitis. Antibiotic regimens are tailored to presentation, which is markedly variable and not well defined for any atypical disease. In cases of spinal instability, the use of antibiotics alone may not be sufficient. Atlantoaxial instability caused by osteomyelitis is a rare complication of CSD. In this report, we describe the rare case of vertebral osteomyelitis complicated by atlantoaxial instability, requiring both antibiotics and atlantoaxial fusion. We discuss our case, surgical technique, rationale, and outcome. In addition, we conducted a systematic review of the literature of vertebral osteomyelitis in pediatric secondary to B. henselae. A 2-year-old child presented with a 2-month history of irritability, fever, and rigid neck pain along with a recent history of feline exposure. Physical examination revealed cervical tenderness and decreased range of motion. Computed tomography (CT) showed osteolysis of the right C1 lateral mass and pars articularis; T1-weighted magnetic resonance imaging with contrast showed enhancement around the right C1 lateral mass. The titer for B. henselae was high. A diagnosis of cat scratch osteomyelitis with cervical instability was made, for which the patient underwent surgery with atlantoaxial fusion. Postoperative imaging demonstrated resolution of the contrast-enhanced lesion. At 6-year follow-up, the patient showed no signs of residual complications from surgical intervention with a solid fusion. Our review revealed 44 cases of pediatric CSD vertebral osteomyelitis. Conservative management with antibiotic employed in 86% while antibiotics with surgical intervention in 14% of the cases. Surgical intervention was most often in the form of incision for drainage and decompression without fusion. Average follow-up 10 months with 86% achieved complete resolution. Cervical instability caused by osteolysis is a rare complication of CSD. This can subsequently lead to vertebral instability, requiring definitive surgical intervention.

Revisiting the Vertebral Venous Plexus-A Comprehensive Review of the Literature.

The venous drainage of the vertebral and paravertebral regions is important for a better understanding of hematogenous disease spread. Moreover, the spine surgeon must be well acquainted with this anatomy to minimize intraoperative and postoperative complications. A comprehensive review of the vertebral venous plexus (Batson plexus) was performed with a concentration on the clinical and surgical correlations of this venous network.

Sacral fractures: An updated and comprehensive review.

Sacral fractures are often underdiagnosed but are relatively frequent in the setting of pelvic ring injury. Causes include traumatic insults and osteoporosis. Sacral fractures have become more frequent owing to the growth of the elderly population worldwide as osteoporosis is an age-related disease. Misdiagnosed and neglected sacral fractures can result in chronic back pain, spine deformity, and instability. Unfortunately, the wide range of classification systems hinders adequate communication among clinicians. Therefore, a complete understanding of the pathology, and communication within the interdisciplinary team, are necessary to ensure adequate treatment and satisfactory clinical outcomes. The aim of this manuscript is to present the current knowledge available regarding classification systems, clinical assessment, decision-making factors, and current treatment options.

Spinal pigmented villonodular synovitis and tenosynovial giant cell tumor: A report of two cases and a comprehensive systematic review.

BACKGROUND AND OBJECTIVE: Pigmented villonodular synovitis (PVNS) is a lesion of uncertain etiology that involves the synovial membranes of joints or tendon sheaths, representing a diffuse and non-encapsulated form of the more common giant cell tumors of the synovium (GCTTS). PVNS was reclassified to denote a diffuse form of synovial giant cell tumor (TSGCT), while 'giant cell tumor of the tendon sheath (GCTTS)' was used for localized lesions. These pathologies rarely affect the axial skeleton. We provide an unprecedented and extensive systematic review of both lesions highlighting presentation, diagnostic considerations, treatment, prognosis, and outcomes, and we report a short case-series. METHOD: We describe two-cases and conduct a systematic review in accordance with PRISMA guidelines. RESULT: PVNS was identified in most of the cases reviewed (91.6 %), manifesting predominantly in the cervical spine (40 %). Patients commonly presented with neck pain (59 %), back pain (53 %), and lower back pain (81.2 %) for cervical, thoracic, and lumbar lesions, respectively. GTR occurred at rates of 94 %, 80 %, and 87.5 %. Recurrence was most common in the lumbar region (30.7 %). GCTTS cases (8%) manifested in the cervical and thoracic spine at the same frequency. We reported first case of GCTTS in the lumbosacral region. Both poses high rate of facet and epidural involvements. CONCLUSION: Spinal PVNS and GCTTS are rare. These lesions manifest most commonly as PVNS within the cervical spine. Both types have a high rate of facet and epidural involvement, while PVNS has the highest rate of recurrence within the lumbar spine. The clinical and radiological features of these lesions make them difficult to differentiate from others with similar histogenesis, necessitating tissue diagnosis. Proper management via GTR resolves the lesion, with low rates of recurrence.

Effects of the COVID-19 Pandemic on Operative Volume and Residency Training at Two Academic Neurosurgery Centers in New Orleans.

BACKGROUND: Medical subspecialties including neurosurgery have seen a dramatic shift in operative volume in the wake of the coronavirus disease 2019 (COVID-19) pandemic. The goal of this study was to quantify the effects of the COVID-19 pandemic on operative volume at 2 academic neurosurgery centers in New Orleans, Louisiana, USA from equivalent periods before and during the COVID-19 pandemic. METHODS: A retrospective review was conducted analyzing neurosurgical case records for 2 tertiary academic centers from March to June 2020 and March to June 2019. The records were reviewed for variables including institution and physician coverage, operative volume by month and year, cases per subspecialty, patient demographics, mortality, and morbidity. RESULTS: Comparison of groups showed a 34% reduction in monthly neurosurgical volume per institution during the pandemic compared with earlier time points, including a 77% decrease during April 2020. There was no change in mortality and morbidity across institutions during the pandemic. CONCLUSIONS: The COVID-19 pandemic has had a significant impact on neurosurgical practice and will likely continue to have long-term effects on patients at a time when global gross domestic products decrease and relative health expenditures increase. Clinicians must anticipate and actively prepare for these impacts in the future.

Preliminary Findings After Nonoperative Management of Traumatic Cervical Spinal Cord Injury on a Background of Degenerative Disc Disease: Providing Optimum Patient Care and Costs Saving in a Nigerian Setting.

OBJECTIVE: We assessed the hypothesis that nonoperative management would be a viable treatment option for patients with underlying degenerative disease who have traumatic cervical spinal cord injury (TCSI) without neurological deterioration and/or spinal instability during hospitalization. METHODS: Data were collected prospectively from 2011 to 2016. All the patients had been treated nonoperatively with hard cervical collar immobilization. The clinical parameters assessed included the Frankel grade at presentation and discharge, the occurrence of deep vein thrombosis, urinary tract infection, sphincter dysfunction, and pressure sores. The radiographic data collected included magnetic resonance imaging signal cord changes. P ≤ 0.05 represented a significant association between the Frankel grade at presentation and the outcome parameters. RESULTS: A total of 28 patients were included in the present study. Of the patients who had presented with Frankel grade B, 85.71% had improved to a higher grade, 90.91% of the patients with Frankel grade C had improved to a higher grade, and 14.29% of the patients with Frankel grade D had improved to Frankel grade E. All the patients had satisfactory spinal stability, as evidenced by dynamic radiographs, after treatment. CONCLUSION: The findings from the present study have shown that nonoperative management can result in improved neurological outcomes for patients with underlying degenerative disease who have experienced TCSI without evidence of neurological deterioration and spinal instability. The Frankel grade at presentation was significantly associated with outcome parameters such as the neurological outcome on discharge and the occurrence of urinary tract infection. The results from the present study could be helpful to neurological surgeons in rural and other low-resource settings because the cost savings realized by nonoperative treatment will not sacrifice the provision of adequate care to their patients.

Recurrent arachnoid cysts secondary to spinal adhesive arachnoiditis successfully treated with a ventriculoperitoneal shunt.

Spinal adhesive arachnoiditis (SAA) with cyst formation secondary to infectious meningitis is a rare clinical entity. These cysts can compress the spinal cord and cause neurologic decline. We present a case of a patient who underwent resection for an intradural schwannoma which was complicated post-operatively by bacterial meningitis and development of several recurrent thoracic arachnoid cysts. After two separate thoracic decompressions with lysis of intradural adhesions, a permanent ventriculoperitoneal shunt (VPS) was eventually placed with complete recovery of his symptoms. Our review of the literature showed that CSF shunts have previously been successfully used to treat spinal fluid collections. Although there are many factors to consider when treating these patients, CSF diversion may be beneficial for similar SAA presentations in order to simultaneously treat and prevent recurrence of symptoms.

Multistage surgical repair for split notochord syndrome with neuroenteric fistula: case report.

Split notochord syndrome (SNS) is a rare congenital defect of the central nervous system and has been associated with several anomalies affecting multiple organ systems. One association has been communication with the gastrointestinal tract and the spine, previously identified as a neuroenteric fistula (NEF). Here, the authors describe the unique case of a female infant with SNS and NEF treated with a multistage surgical repair. The three-stage operative plan included a two-stage repair of the defect and temporary subgaleal shunting followed by delayed ventriculoperitoneal shunt placement. The infant recovered well postsurgery and over a 5-year follow-up. A case description, surgical techniques, and rationale are reported. Additionally, a systematic review of the literature utilizing the MEDLINE database was performed.Treatment of SNS with NEF using a multidisciplinary multistaged approach to repair the intestinal defect, close the neural elements, and divert cerebrospinal fluid to the peritoneum is shown to be a safe and viable option for future cases.

Neurological Impact of Coronavirus Disease of 2019: Practical Considerations for the Neuroscience Community.

BACKGROUND: The coronavirus disease of 2019 (COVID-19), which is caused by infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has recently been designated a pandemic by the World Health Organization, affecting 2.7 million individuals globally as of April 25, 2020, with more than 187,000 deaths. An increasing body of evidence has supported central nervous system involvement. METHODS: We conducted a review of the reported data for studies concerning COVID-19 pathophysiology, neurological manifestations, and neuroscience provider recommendations and guidelines. RESULTS: Central nervous system manifestations range from vague nonfocal complaints to severe neurological impairment associated with encephalitis. It is unclear whether the neurological dysfunction results from direct viral injury or systemic disease. The virus could affect brainstem pathways that lead to indirect respiratory dysfunction, in addition to direct pulmonary injury. Necessary adaptations in patient management, triage, and diagnosis are evolving in light of the ongoing scientific and clinical findings. CONCLUSIONS: The present review has consolidated the current body of data regarding the neurological impact of coronaviruses, discussed the reported neurological manifestations of COVID-19, and highlighted the recommendations for patient management. Specific recommendations pertaining to clinical practice for neurologists and neurosurgeons have also been provided.

Iatrogenic spinal cord injury with tetraplegia after an elective non-spine surgery with underlying undiagnosed cervical spondylotic myelopathy: Literature review and case report.

Cervical spondylotic myelopathy (CSM) can predispose to acute spinal cord injury and post-operative quadriparesis during non-spine procedures, although few accounts of this phenomenon exist within the literature. To the best of our knowledge, there are only 18 cases reported in the literature including ours with spinal cord injury following elective non-spine surgery with undiagnosed CSM. Due to multifactorial pathophysiology, the maintenance of cervical cord neutrality is not sufficient to ensure that these patients will not sustain cord injury intraoperatively as this solely addresses the role of static factors. Vigilance to factors affecting cord perfusion and vascular compromise, such as the mean arterial pressure (MAP), is imperative. Additionally, further studies should evaluate the role of positioning in the myelopathic patient and whether the steep Trendelenburg position, commonly used in robotic surgeries, contributes to spinal cord venous congestion and resultant cord ischemia in these patients given their baseline stenotic canal. This review illustrates the importance of having a heightened awareness of this common degenerative condition in our aging patient population, often a forgotten underlying medical comorbidity.

Suture Choice in Lumbar Dural Closure Contributes to Variation in Leak Pressures: Experimental Model.

STUDY DESIGN: Open-label laboratory investigational study; non-animal surgical simulation. OBJECTIVE: The authors perform a comparison of dural closure strength in a durotomy simulator across 2 different suture materials. SUMMARY OF BACKGROUND DATA: Incidental durotomy leading to persistent cerebrospinal fluid leak adds considerable morbidity to spinal procedures, often complicating routine elective lumbar spinal procedures. Using an experimental durotomy simulation, the authors compare the strength of closure using Gore-Tex with other suture types and sizes, using various closure techniques. METHODS: A comparison of dural closures was performed through an analysis of the peak pressure at which leakage occurred from a standardized durotomy closure in an established cerebrospinal fluid repair model with a premade L3 laminectomy. Nurolon was compared with Gore-Tex sutures sizes (for Gore-Tex, CV-6/5-0 and CV-5/4-0 was compared with Nurolon 4-0, 5-0, and 6-0). RESULTS: Thirty-six trials were performed with Nurolon 4-0, 5-0, and 6-0, whereas 21 trials were performed for 4-0 and 5-0 Gore-Tex. The mean peak pressure at which fluid leakage was observed was 21 cm H2O for Nurolon and 34 cm H2O for Gore-Tex. Irrespective of suture choice, all trials were grouped by closure technique: running suture, locked continuous, and interrupted suture. No significant difference was noted between the groups. For each of the 3 trials groups by closure technique, running, locked continuous, and interrupted, Gore-Tex closures had a significantly higher peak pressure to failure. Interrupted Gore-Tex was significantly higher than Interrupted Nurolon (P=0.007), running Gore-Tex was significantly higher than running Nurolon (P=0.034), and locked Gore-Tex was significantly higher than locked Nurolon (P=0.014). CONCLUSIONS: Durotomy closure in the lumbar spine with Gore-Tex suture may be a reasonable option for providing a watertight closure. In this laboratory study, Gore-Tex suture provided watertight dural closures that withstood higher peak pressures.

Cortical bone facet spacers for cervical spine decompression: effects on intervertebral kinetics and foraminal area.

OBJECTIVE: Nerve root decompression to relieve pain and radiculopathy remains one of the main goals of fusion-promoting procedures in the subaxial cervical spine. The use of allograft facet spacers has been suggested as a potential alternative for performing foraminotomies to increase the space available for the cervical nerve roots while providing segmental stiffening. Therefore, the goal of this cadaveric biomechanical study was to determine the acute changes in kinetics and foraminal area after the insertion of cortical bone facet spacers into the subaxial cervical spine. METHODS: Allograft spacers (2 mm in height) were placed bilaterally into cadaveric cervical spine specimens (C2-T1, age of donors 57.5 ± 9.5 years, n = 7) at 1 (C4-5) and 3 (C3-6) levels with and without laminectomies and posterior lateral mass screw fixation. Standard stereophotogrammetry under pure moment loading was used to assess spinal kinetics. In addition, the authors performed 3D principal component analysis of CT scans to determine changes in foraminal cross-sectional area (FCSA) available for the spinal nerve roots. RESULTS: Generally, the introduction of 2-mm-height facet spacers to the cervical spine produced mild, statistically insignificant reductions in motion with particular exceptions at the levels of implantation. No significant adjacent-level motion effects in any bending plane were observed. The addition of the posterior instrumentation (PI) to the intact spines resulted in statistically significant reductions in motion at all cervical levels and bending planes. The same kinetic results were obtained when PI was added to spines that also had facet spacers at 3 levels and spines that had been destabilized by en bloc laminectomy. The addition of 2-mm facet spacers at C3-4, C4-5, and C5-6 did produce statistically significant increases in FCSA at those levels. CONCLUSIONS: The addition of allograft cervical facet spacers should be considered a potential option to accomplish indirect foraminal decompression as measured in this cadaveric biomechanical study. However, 2-mm spacers without supplemental instrumentation do not provide significantly increased spinal segmental stability.

Simulation Training Curricula for Neurosurgical Residents: Cervical Foraminotomy and Durotomy Repair Modules.

INTRODUCTION: Since 2010, the Congress of Neurological Surgeons (CNS) has offered a neurosurgical skills simulation course for residents and medical students. The authors describe their experience with incorporation of two neurosurgical skills simulation modules into the dedicated resident training curriculum of a single ACGME-accredited training program, using lumbar dural repair (5) and posterior cervical laminoforaminotomy modules from the CNS simulation initiative (6). METHODS: Each of the available 22 neurosurgery residents at a single residency program was given two 20-question pretests for a cervical laminoforaminotomy and durotomy repair module as a basic test of regional anatomy, general disease knowledge, surgical decision making, and recently published literature. This was followed by a faculty-directed skills simulation course and concluded with a final 20 question post-test. RESULTS: Posterior cervical laminoforaminotomy was performed once by each resident, and grading was conducted using the predetermined OSATs. The overall score was 56.1 (70%, range 26-76, maximum 80 points) with a trend towards higher scores with advanced levels of training. All residents completed the durotomy repair OSATs for a total of three trials. Of a maximum composite score of 60, a mean 37.2 (62%, range 15-58) was scored by the residents (Table 3). The mean OSAT scores for each durotomy trial was 2.66, 3.15, and 3.48 on each success test. A trend towards higher scores in advanced years of training was observed, but did not reach statistical significance (Figure 3). CONCLUSIONS: Duty hour limitations and regulatory pressure for enhanced quality and outcomes may limit access of neurosurgical residents to fundamental skills training. Fundamental skills training as part of a validated simulation curriculum can mitigate this challenge to residency education. National development of effective technical simulation modules for use in individual residency training programs is a promising strategy to achieve these goals.