Journal of neurosurgery. Spine
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Case Reports
Bow hunter's syndrome: the use of dynamic magnetic resonance angiography and intraoperative fluorescent angiography.
Bow hunter's syndrome is a diagnosis typically made using dynamic digital subtraction angiography. The authors present the case of a 68-year-old woman who presented with symptoms consistent with bow hunter's syndrome that was accurately diagnosed utilizing noninvasive dynamic MR angiography. The dynamic MR angiogram clearly illustrated unilateral vertebral artery compression upon turning of the head. ⋯ It can also be used to confirm sufficient postoperative decompression and monitor for recurrence. Intraoperative fluorescent angiography has been previously used in the evaluation of intracranial and extracranial vascular patency. This report is the first to show that fluorescent angiography can offer rapid and reliable intraoperative evaluation of vertebral artery decompression in bow hunter's syndrome.
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Although multimodal intraoperative spinal cord monitoring provides greater accuracy, transcranial electrical stimulation motor evoked potential (TcMEP) monitoring became the gold standard for intraoperative spinal cord monitoring. However, there is no definite alarm point for TcMEPs because a multicenter study is lacking. Thus, based on their experience with 48 true-positive cases (that is, a decrease in potentials followed by a new neurological motor deficit postoperatively) encountered between 2007 and 2009, the authors set a 70% decrease in amplitude as the alarm point for TcMEPs. ⋯ This study is the first prospective multicenter study to investigate the alarm point of TcMEPs. The authors recommend the designation of an alarm point of a 70% decrease in amplitude for routine spinal cord monitoring, particularly during surgery for spinal deformity, OPLL, and extramedullary spinal cord tumor.
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Randomized Controlled Trial
Unilateral pedicle screw fixation through a tubular retractor via the Wiltse approach compared with conventional bilateral pedicle screw fixation for single-segment degenerative lumbar instability: a prospective randomized study.
Treatment of patients with single-segment degenerative lumbar instability using unilateral pedicle screw fixation can achieve stability and fusion rates similar to those of bilateral pedicle screw fixation. The aim of this study was to analyze the clinical outcome of using unilateral pedicle screw fixation through a tubular retractor via the Wiltse approach to treat single-segment degenerative lumbar instability. ⋯ Unilateral pedicle screw fixation through a tubular retractor via the Wiltse approach appears to be as safe and effective as bilateral pedicle screw fixation for the treatment of single-segment degenerative lumbar instability.
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Case Reports
Vascular injury following microendoscopic lumbar discectomy treated with stent graft placement.
The risk of great vessel injury is low in microendoscopic lumbar discectomy applied in a favorable visual field. However, it is important to be aware of the depth of the pituitary rongeur. In this article, the authors report the case of a 55-year-old woman with lumbar disc herniation who underwent microendoscopic discectomy and subsequently presented with an aneurysm and arteriovenous fistula located at the bifurcation of the right common iliac artery. The patient was treated with endoscopic placement of a stent graft and recovered uneventfully.
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Observational Study
Prospective observational study of acute postlumbar laminectomy MRI.
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. ⋯ 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.