The intercostal nerve as a target for diagnostic biopsy.

OBJECTIVE Peripheral nerve biopsy is a useful tool in diagnosing peripheral neuropathies. Sural and gracilis nerves have become the most common targets for nerve biopsy. However, the yield of sural nerve biopsy is limited in patients who have motor neuropathies, and gracilis nerve biopsy presents technical challenges and increased complications. The authors propose the intercostal nerve as an alternative motor nerve target for biopsy. METHODS A total of 4 patients with suspected peripheral neuropathies underwent intercostal nerve biopsy at the authors' institution. A rib interspace that is inferior to the pectoralis muscle and anterior to the anterior axillary line is selected for the procedure. Generally the lower intercostal nerves (i.e., T7-11) are targeted. An incision is made over the inferior aspect of the superior rib at the chosen interspace. Blunt dissection is carried down to the neurovascular bundle and the nerve is isolated, ligated, and cut to send for pathological examination. RESULTS The average operative time for all cases was 73 minutes, with average blood loss of 8 ml. Biopsy results from 1 patient exhibited axonopathy, and the other 3 patients demonstrated axonopathy with demyelination. There were no short- or long-term postoperative complications. None of the patients reported sensory or motor deficits related to the biopsy at 6 weeks postoperatively. CONCLUSIONS The intercostal nerve can be an alternative target for biopsy, especially in patients with predominantly motor neuropathies, due to its mixed sensory and motor fibers, straightforward anatomy, minimal risk of serious sensory deficits, and no risk of motor impairment.

Spinal sealant system provides better intraoperative watertight closure than standard of care during spinal surgery: a prospective, multicenter, randomized controlled study.

STUDY DESIGN: Prospective, 3:1 randomized, single-blind, multicenter investigational study. OBJECTIVE: To assess the safety and efficacy of a low-swell spinal sealant when used as an adjunct to sutured dural repair compared with standard of care methods to obtain watertight dural closure in subjects undergoing spinal surgery. SUMMARY OF BACKGROUND DATA: Watertight dural closure is paramount in spinal surgery to avoid complications of cerebrospinal fluid leak. Prior reports have proven the efficacy of a synthetic, absorbable polyethylene glycol (PEG) hydrogel sealant in spinal surgery compared with standard of care. Given the potential concerns of swelling in spinal applications, the hydrogel was modified to a low-swell formulation. METHODS: The primary endpoint was success rate in obtaining intraoperative watertight dural closure in subjects receiving PEG hydrogel sealant versus a control group of subjects receiving any standard method designed to provide intraoperative watertight closure. Subjects were evaluated at discharge and at 30 and 90 days postprocedure for cerebrospinal fluid leaks, surgical site infections, and adverse events. RESULTS: Between May 2007 and May 2009, 98 subjects (74 PEG hydrogel spinal sealant, 24 control) were randomized at 14 clinical sites in the United States. Patients treated with the PEG hydrogel spinal sealant had a significantly higher rate of watertight closure than the control (98.6% vs. 79.2%, P = 0.003). No statistical differences were seen in postoperative cerebrospinal fluid, infection, and wound healing. No neurological deficits were seen attributable to the sealant. CONCLUSION: The low-swell PEG hydrogel spinal sealant evaluated in this study has been proven safe and effective for providing watertight closure when used as an adjunct to sutured closure of intentional durotomies during spinal surgery. PEG hydrogel sealants have again proved superior to other standard of care technologies for safe, efficacious dural closure. LEVEL OF EVIDENCE: 2.

Technical note: Resolution of spontaneous electromyographic discharge following disk-space distraction during lateral transpsoas interbody fusion.

PURPOSE: The lateral transpsoas interbody fusion (LTIF) is an increasingly popular minimally invasive technique for lumbar interbody fusion. Although a posterior approach to the lumbar spine has traditionally been favored for the treatment of canal stenosis and neural foraminal stenosis, a growing body of evidence suggests that indirect decompression of the spinal canal and neural foramen can be achieved using a lateral transpsoas approach to the lumbar spine. We present 2 cases that may suggest a role for spontaneous electromyography (s-EMG) monitoring in assessing the adequacy of decompression during LTIF. METHODS: The 2 cases presented in this technical note illustrate resolution of s-EMG firing during LTIF, following distraction across the disk space. Removal of the distracting device produced the return of s-EMG firing. Both of these cases were operated at the L2-3 level. RESULTS: In the first case, s-EMG firing was noted in the bilateral tibialis anterior leads. Resolution of EMG firing may suggest indirect decompression of the canal via ligamentotaxis as the L5 root traverses the L2-3 disk space. In the second case, s-EMG firing was noted in the left abductor hallucis and resolved with distraction of the L2-3 disk space. Again, this may be explained by canal decompression via ligamentotaxis as the S1 root traverses the L2-3 disk space. CONCLUSION: In both cases, distraction across the disk space resulted in resolution of s-EMG discharges-this correlated with an improvement in symptoms. These findings may suggest a role for s-EMG as a marker for adequacy of decompression in a select subset of patients undergoing LTIF. Further study is needed to determine if resolution of s-EMG is a useful measure of indirect decompression during LTIF.

Intraventricular dysembryoplastic neuroepithelial tumor in a pediatric patient: is it the most common extracortical location for DNT?

Dysembryoplastic neuroepithelial tumor (DNT) is commonly located in the supratentorial cortex. Extracortical localization of DNT is extremely rare. A 15-year-old female presented with loss of consciousness after head trauma. MRI demonstrated hydrocephalus secondary to a small non-enhancing T1 hypointense and T2 hyperintense mass lesion in the foramen of Monro; with radiologic impression of low-grade astrocytoma or colloid cyst. Tumor was gross totally resected. Histologic examination showed partly microcystic architecture with oligodendroglia-like neurocytic cells, glioneuronal element, and floating neurons, with synaptophysin reactivity mainly in cell processes, consistent with DNT. Focal subependymoma-like pattern was noted. The low tumor cellularity and morphologic pattern did not support a central neurocytoma. Patient was asymptomatic and was radiologically stable 9 months post-surgery. Literature review of previously reported supratentorial extracortical DNT cases demonstrate that 24 of 25 cases involved the ventricular system (as in our case) of which eight additionally involved periventricular deep gray or white matter. None of the cases recurred following surgery. Clinico-pathologically, extracortical DNTs were similar to the cerebral cortical simple DNTs and differed only in their presentation related to their location. The novel aspects of this report are the radiologic resemblance of DNT to colloid cyst and focal subependymoma-like pattern on histology. Importantly, intra-/periventricular region appears to be the most common extracortical location of cerebral DNT with a 100% disease-free survival reported in the literature.

Diagnosis and management of juxtafacet cysts.

Juxtafacet cysts are lesions that are associated with spinal facet joints. Although these lesions are frequently noted as incidental findings on imaging studies of the spine, they may produce symptoms in some patients. Juxtafacet cysts can mimic herniated discs, resulting in symptoms from focal nerve root and/or spinal cord compression. Some of these lesions are associated with spinal instability, and patients may require spinal fusion to address this underlying disorder. Conservative therapy for symptomatic lesions is often unsuccessful, although there are reports of spontaneous resolution of these cysts as well as the symptoms associated with them. Surgical therapy should be focused on decompression of the lesions causing nerve root compression and the accompanying symptoms, while recognizing that instability requiring fusion may be present in some but not all cases.

Paramedian approach for transforaminal lumbar interbody fusion with unilateral pedicle screw fixation. Technical note and preliminary report on 47 cases.

Lumbar fusion is a commonly performed procedure for a variety of pathological conditions, and it is frequently used in the treatment of degenerative lumbar instability that is refractory to medical management. Pedicle screws and interbody devices have been used for internal fixation to promote arthrodesis, prevent nonunion, and facilitate early mobilization. Recently, attempts have been made to reduce the morbidity associated with lumbar fusion by using a variety of minimally invasive techniques. Many minimally invasive lumbar fusion procedures require specialized retractors, implants, image guidance systems, or insertion instruments. Other minimally invasive techniques are primarily applied to an ideal patient population (thin, healthy, and with no previous surgery). The authors describe their experience with a paramedian approach for minimally invasive transforaminal lumbar interbody fusion (TLIF) with unilateral pedicle screw (PS) fixation. This procedure requires only standard implants, instruments, and retractors, with direct visualization for all aspects of the procedure. The authors describe encouraging early results in a challenging patient population in which there was a high incidence of obesity, medical comorbidities, and previous surgery at the same level. The paramedian approach for TLIF performed using unilateral lumbar PSs has yielded successful outcomes in this series of 47 patients, and further study of this technique may help define its role as a minimally invasive procedure for spinal fusion.

The use of closed-suction irrigation systems to manage spinal infections.

OBJECT: Management of infection in the hardware system-fixated spine has proven to be problematic. In many cases, instrumentation is required to provide stability or to maintain correction of deformity, and removal could be hazardous. The authors describe the use of closed continuous irrigation to treat spinal wound infections in patients with fixation systems; irrigation can be used in all parts of the spine with excellent results. METHODS: The authors conducted a retrospective chart-based review of cases in which spinal instrumentation procedures were performed consecutively during a 10-year period. Infection developed in 36 patients. The infections involved the cervical, thoracic or thoracolumbar, and lumbar regions. Anterior and posterior drains were placed in one patient. In one patient refractory infections responded to replacement of the dual-inflow port drainage system. In all cases the wound infection completely resolved. There were no cases that required the removal of the fusion mass or instrumentation. In all cases progression to solid fusion was achieved. CONCLUSIONS: Closed irrigation systems can be used effectively to manage anterior or posterior cervical, thoracic, and lumbar wound infections. These systems preclude the explantation of the instrumentation and allow spinal stability to be preserved. The authors noted no evidence of recurrent infection or failed fusion.

Results of long-term follow-up in patients undergoing anterior screw fixation for type II and rostral type III odontoid fractures.

STUDY DESIGN: Retrospective analysis of the fusion rate of a group of 38 patients having undergone anterior screw fixation for type II and "shallow" type III odontoid fractures. OBJECTIVE.: To determine primarily the long-term fusion rate after anterior screw fixation and to study the clinical characteristics of patients that have a statistically significant or nonsignificant influence on successful outcome. SUMMARY OF BACKGROUND DATA: Long-term outcome of anterior screw fixation for odontoid fractures has been evaluated in very few studies. This information should be critical for further establishing this technique as a major therapeutic strategy for these cases. METHODS: Thirty-eight patients, 25 males and 13 females (with mean age 48.4 +/- 0.4 years), with type II and rostral type III odontoid fractures, underwent anterior cannulated screw fixation during a 62-month period. Radiologic examination of the cervical spine with plain radiographs was performed at 6 weeks, and 2, 6, 12, and 24 months, while computerized tomography of the upper cervical spine (C1-C3) was obtained at 6 months after surgery. Follow-up was available for 31 patients, and the follow-up time ranged from 39 to 87 months (mean 58.4). RESULTS: Radiographic evaluation of the follow-up group showed satisfactory bony fusion and no evidence of abnormal movement at the fracture site in 27 (87.1%) patients. Pseudarthrosis developed in 4 (12.9%) patients; however, 3 (9.6%) of them without instability and 1 (3.2%) with instability. One (3.2%) patient had an instrumentation failure without instability. CONCLUSIONS: In our series, anterior odontoid screw fixation comprised a safe therapeutic modality with high stability and low mechanical failure rates during short-term and long-term follow-up.

Treatment of atlantoaxial instability in pediatric patients.

The atlantoaxial region has been extensively described as a spinal segment especially prone to injury in children. In this clinical review, the authors evaluate and summarize the management of 23 pediatric cases of atlantoaxial instability treated between March 1990 and October 2002. Four broad categories of atlantoaxial problems were observed-atlantoaxial rotatory subluxation in six patients, anterior-posterior atlantoaxial instability caused by ligamentous injury or congenital ligamentous laxity (10 patients), atlantoaxial fracture with or without dislocation (five patients), and atlantooccipital dislocation (two patients). Most cases (60.9%) were treated without surgical intervention, resulting in excellent outcomes; however, 21.7% of cases were treated with a cervical halo (mean patient age 72.6 months) alone for 3 months. Various techniques of surgical stabilization including transarticular screws with sublaminar wiring, transoral decompression with posterior plating, and laminectomy with Steinmann pin occipital-cervical fusion were used with good results. Both patients with atlantooccipital dislocation underwent immediate Locksley occipital-cervical fusion, with marked neurological improvement. Individualized case management must be based on clinical presentation, with internal fixation being the last resort.