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Laura A. Snyder, Harry Shufflebarger, Michael F. O'Brien, Harjot Thind, Nicholas Theodore and Udaya K. Kakarla

Object

Isthmic spondylolysis can significantly decrease functional abilities, especially in adolescent athletes. Although treatment can range from observation to surgery, direct screw placement through the fractured pars, or Buck's procedure, may be a more minimally invasive procedure than the more common pedicle screw-hook construct.

Methods

Review of surgical databases identified 16 consecutive patients treated with Buck's procedure from 2004 to 2010. Twelve patients were treated at Miami Children's Hospital and 4 at Barrow Neurological Institute. Demographics and clinical and radiographic outcomes were recorded and analyzed retrospectively.

Results

The 16 patients had a median age of 16 years, and 14 were 20 years or younger at the time of treatment. Symptoms included axial back pain in 100% of patients with concomitant radiculopathy in 38%. Pars defects were bilateral in 81% and unilateral in 19% for a total of 29 pars defects treated using Buck's procedure. Autograft or allograft augmented with recombinant human bone morphogenetic protein as well as postoperative bracing was used in all cases. Postoperatively, symptoms resolved completely or partially in 15 patients (94%). Of 29 pars defects, healing was observed in 26 (89.6%) prior to 1 revision surgery, and an overall fusion rate of 97% was observed at last radiological follow-up. There were no implant failures. All 8 athletes in this group had returned to play at last follow-up.

Conclusions

Direct screw repair of the pars interarticularis defect as described in this series may provide a more minimally invasive treatment of adolescent patients with satisfactory clinical and radiological outcomes, including return to play of adolescent athletes.

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Eduardo Martinez-del-Campo, Leonardo Rangel-Castilla, Hector Soriano-Baron and Nicholas Theodore

Object

Performance of MR imaging in patients with gunshot wounds at or near the lumbar spinal canal is controversial. The authors reviewed the literature on the use of MR imaging in gunshot wounds to the spine. They discuss the results from in vitro and clinical studies, analyze the physical properties of common projectiles, and evaluate the safety and indications for MR imaging when metallic fragments are located near the spinal canal.

Methods

A review of the English-language literature was performed. Data from 25 articles were analyzed, including 5 in vitro studies of the interaction between 95 projectiles and the MR system's magnetic fields, and the clinical outcomes in 22 patients with metallic fragments at or near the spinal canal who underwent MR imaging.

Results

Properties of 95 civilian and military projectiles were analyzed at a magnet strength of 1, 1.5, 3, and 7 T. The most common projectiles were bullets with a core of lead, either with a copper jacket or unjacketed (73 [76.8%] of 95). Steel-containing (core or jacket) projectiles comprised 14.7%. No field interaction was evident in 78 (96.3%) of the 81 nonsteel projectiles. All steel projectiles showed at least positive deflection forces, longitudinal migration, or rotation. Heating of the projectiles was clinically insignificant. Image artifact was significant in all 9 steel bullets tested, but was not significant in 39 (88.6%) of the 44 nonsteel bullets tested. Overall, 22 patients with complete (82%) and incomplete (14%) spinal cord injury secondary to a projectile lodged inside the spinal canal underwent MR imaging. Discomfort and further physical or neurological deficits were not reported by any patient. Two patients with spinal cord injuries underwent MR imaging studies before surgical decompression and had subsequent, significant neurological improvement.

Conclusions

Metallic implants near or at the spinal canal are a relative contraindication for MR imaging. However, safe MR imaging might be feasible when a projectile's properties and a patient's individualized clinical presentation are considered.

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Sam Safavi-Abbasi, Adrian J. Maurer, Jacob B. Archer, Ricardo A. Hanel, Michael E. Sughrue, Nicholas Theodore and Mark C. Preul

During his lifetime and a career spanning 42 years, James Watson Kernohan made numerous contributions to neuropathology, neurology, and neurosurgery. One of these, the phenomenon of ipsilateral, false localizing signs caused by compression of the contralateral cerebral peduncle against the tentorial edge, has widely become known as “Kernohan's notch” and continues to bear his name. The other is a grading system for gliomas from a neurosurgical viewpoint that continues to be relevant for grading of glial tumors 60 years after its introduction. In this paper, the authors analyze these two major contributions in detail within the context of Kernohan's career and explore how they contributed to the development of neurosurgical procedures.

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Scott D. Wait, M. Yashar S. Kalani, Andrew S. Little, Giac D. Consiglieri, Jeffrey S. Ross, Matthew R. Kucia, Volker K. H. Sonntag and Nicholas Theodore

Object

Patients who develop a lower-extremity neurological deficit after lumbar laminectomy present a diagnostic dilemma. In the setting of a neurological deficit, some surgeons use MRI to evaluate for symptomatic compression of the thecal sac. The authors conducted a prospective observational cohort study in patients undergoing open lumbar laminectomy for neurogenic claudication to document the MRI appearance of the postlaminectomy spine and to determine changes in thecal sac diameter caused by the accumulation of epidural fluid.

Methods

Eligible patients who were candidates for open lumbar laminectomy for neurogenic claudication at a single neurosurgical center between August 2007 and June 2009 were enrolled. Preoperative and postoperative MRI of the lumbar spine was performed on the same MRI scanner. Postoperative MRI studies were completed within 36 hours of surgery. Routine clinical and surgical data were collected at the preoperative visit, during surgery, and postoperatively. Images were interpreted for the signal characteristics of the epidural fluid and for thecal diameter (region of interest [ROI]) by 2 blinded neuroradiologists.

Results

Twenty-four patients (mean age 69.7 years, range 30–83 years) were enrolled, and 20 completed the study. Single-level laminectomy was performed in 6 patients, 2-level in 12, and 3-level in 2. Preoperative canal measurements (ROI) at the most stenotic level averaged 0.26 cm2 (range 0.0–0.46 cm2), and postoperative ROI at that same level averaged 0.95 cm2 (range 0.46–2.05 cm2). The increase in ROI averaged 0.69 cm2 (range 0.07–1.81 cm2). Seven patients (35%) had immediate postoperative weakness in at least 1 muscle group graded at 4+/5. The decline in examination was believed to be effort dependent and secondary to discomfort in the acute postoperative period. Those with weakness had smaller increases in ROI (0.51 cm2) than those with full strength (0.78 cm2, p = 0.1599), but none had evidence of worsened thecal compression. On the 1st postoperative day, 19 patients were at full strength and all patients were at full strength at their 15-day follow-up. The T1-weighted epidural fluid signal was isointense in 19 of the 20 patients. The T2-weighted epidural fluid signal was hyperintense in 9, isointense in 4, and hypointense in 7 patients.

Conclusions

Immediately after lumbar laminectomy, the appearance of the thecal sac on MRI can vary widely. In most patients the thecal sac diameter increases after laminectomy despite the presence of epidural blood. In this observational cohort, a reduction in thecal diameter caused by epidural fluid did not correlate with motor function. Results in the small subset of patients where the canal diameter decreased due to epidural fluid compression of the thecal sac raises the question of the utility of immediate postoperative MRI.

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Nicholas Theodore, M. Yashar S. Kalani and Volker K. H. Sonntag

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Owoicho Adogwa, Ricardo K. Carr, Katherine Kudyba, Isaac Karikari, Carlos A. Bagley, Ziya L. Gokaslan, Nicholas Theodore and Joseph S. Cheng

Object

Same-level recurrent lumbar stenosis, pseudarthrosis, and adjacent-segment disease (ASD) are potential complications that can occur after index lumbar spine surgery, leading to significant discomfort and radicular pain. While numerous studies have demonstrated excellent results following index lumbar spine surgery in elderly patients (age > 65 years), the effectiveness of revision lumbar surgery in this cohort remains unclear. The aim of this study was to assess the long-term effectiveness of revision lumbar decompression and fusion in the treatment of symptomatic pseudarthrosis, ASD, and same-level recurrent stenosis, using validated patient-reported outcomes.

Methods

After a review of the institutional database, 69 patients who had undergone revision neural decompression and instrumented fusion for ASD (28 patients), pseudarthrosis (17 patients), or same-level recurrent stenosis (24 patients) were included in this study. Baseline and 2-year scores on the visual analog scale for leg pain (VAS-LP), VAS for back pain (VAS-BP), Oswestry Disability Index (ODI), and Zung Self-Rating Depression Scale (SDS) as well as the time to narcotic independence, time to return to baseline activity level, health state utility (EQ-5D, the EuroQol-5D health survey), and physical and mental component summary scores of the 12-Item Short-Form Health Survey (SF-12 PCS and MCS) were assessed.

Results

Compared with the preoperative status, VAS-BP was significantly improved 2 years after surgery for ASD (mean ± standard deviation 9 ± 2 vs 4.01 ± 2.56, p = 0.001), pseudarthrosis (7.41 ± 1 vs 5.52 ± 3.08, p = 0.02), and same-level recurrent stenosis (7 ± 2.00 vs 5.00 ± 2.34, p = 0.003). The 2-year ODI was also significantly improved after surgery for ASD (29 ± 9 vs 23.10 ± 10.18, p = 0.001), pseudarthrosis (28.47 ± 5.85 vs 24.41 ± 7.75, p = 0.001), and same-level recurrent stenosis (30.83 ± 5.28 vs 26.29 ± 4.10, p = 0.003). The Zung SDS score and SF-12 MCS did not change appreciably after surgery in any of the cohorts, with an overall mean 2-year change of 1.01 ± 5.32 (p = 0.46) and 2.02 ± 9.25 (p = 0.22), respectively.

Conclusions

Data in this study suggest that revision lumbar decompression and extension of fusion for symptomatic pseudarthrosis, ASD, and same-level recurrent stenosis provides improvement in low-back pain, disability, and quality of life and should be considered a viable treatment option for elderly patients with persistent or recurrent back and radicular pain. Mental health symptoms may be more refractory to revision surgery.

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Michael J. Schneider

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Luis M. Tumialán and Nicholas Theodore

Traumatic cervical spondyloptosis is a rare clinical entity typically associated with complete neurological deficit. The inherent mechanics of this fracture-dislocation pattern contorts the vertebral arteries in such a way that it may result in dissection or compromised flow through those vessels. Thus, intimal injury or thrombus from stasis of flow may result. Reduction of the spondyloptosis restores flow to the vertebral arteries, but it also may mobilize thrombus or propagate an intimal dissection within the previously contorted vessel.

The authors review their experience in the care of a 43-year-old man who sustained C4–5 spondyloptosis while riding an all-terrain vehicle. On arrival, the patient demonstrated no motor function below C-4 but had sensation to the nipple line (American Spinal Injury Association Spinal Cord Injury Classification B). The patient's cranial nerve examination was unremarkable. Computed tomography of the cervical spine demonstrated complete spondyloptosis at C4–5. The patient was immediately placed in cervical traction and taken to the operating room for open reduction of the fracture dislocation, decompression of the spinal cord, and stabilization with an interbody graft and cervical plate. Preoperative cervical traction was successful in only partial reduction of the fracture dislocation. Open reduction was achieved with exposure of the C-4 and C-5 bodies and sequential distraction. After anatomical alignment was achieved, an interbody graft was placed and a cervical plate secured. A subsequent decline in the patient's level of consciousness prompted CT of the head, which showed evidence of a basilar artery thrombosis. A CT angiographic study demonstrated patency of the vertebral arteries, but a mid–basilar artery thrombosis. The patient progressed to brain death 24 hours after reduction of the fracture dislocation.

The degree of contortion of the vertebral arteries in cervical spondyloptosis in the upper cervical spine may result in stasis of flow with subsequent formation of thrombus or intimal injury. After anatomical reduction, restoration of flow within the vertebral arteries may mobilize the thrombus or propagate an intimal dissection and result in subsequent embolic events. Endovascular evaluation may be warranted immediately after anatomical reduction of a high cervical spondyloptosis for evaluation of the vertebral arteries and possible thrombus dissolution or retrieval.