Faculty Bibliography

BACKGROUND:Idiopathic spinal cord herniation is a disorder in which the spinal cord herniates through a dural defect. We present a case in which both the standard surgical method and a salvage method failed. CASE DESCRIPTION/METHODS:A 36 year-old man presented with two years of progressive numbness and proximal hip flexion weakness of both lower extremities. MRI of the thoracic spine was suggestive for a ventral spinal cord herniation at the T6/7 level. He was initially treated with reduction of his cord herniation, placement of a ventral sling of collagen matrix over the dural defect to prevent re-herniation, with a laminoplasty. He developed a blood-pressure-dependent paraparesis that did not recover despite a return to the OR for removal of the laminoplastic bone flap. He was again taken to the OR, the sling was removed and we enlarged the ventral dural defect rostrally and caudally to prevent strangulation of the hernia as described by Watanabe. Though in the short term he was able to recover and transfer to physical therapy, after going home he developed lower extremity weakness and low-pressure headaches. MRI showed a ventral epidural CSF pocket retropulsing the spinal cord, as well as pockets of ventral CSF collections remote from the surgery site. The patient returned to the OR and the initial surgery with the ventral sling was re-performed with resolution of the headaches and was neurologically stable and transferred to rehab. Long-term he developed left intercostal pain at the level of the surgery without radiological correlate. CONCLUSION/CONCLUSIONS:In this patient there was no single satisfactory surgical treatment of his ventrally herniated spinal cord - partly related to the herniated component of the cord acting as a mass within a narrow canal at the apex of the thoracic kyphosis. We encountered previously unreported complications of the ventral defect widening technique of surgical treatment.

PURPOSE: Primary hyperhidrosis is a pathological disorder of unknown etiology, affecting 0.6-5% of the population, and causing severe functional and social handicaps. As the etiology is unknown, it is not possible to treat the root cause. Recently some differences between affected and non-affected people have been reported. The aim of this review is to summarize these new etiological data. METHODS: Search of the literature was performed in the PubMed/Medline Database and pertinent articles were retrieved and reviewed. Additional publications were obtained from the references of these articles. RESULTS: Some anatomical and pathophysiological characteristics (as well as enzymatic, metabolic, and neurological dysfunctions) have been observed in hyperhidrotic subjects; three main possible etiological factors predominate. A familial trait seems to exist, and genetic loci associated with hyperhidrosis have been identified. Histological differences were observed in sympathetic ganglia of hyperhidrotic subjects: the ganglia were larger and contained a higher number of ganglion cells. A higher expression of acetylcholine and alpha-7 neuronal nicotinic receptor subunit in the sympathetic ganglia of patients with hyperhidrosis has been reported. CONCLUSIONS: Despite these accumulated data, the etiology of primary hyperhidrosis remains obscure. Nevertheless, three main lines for future research seem to be delineated: genetics, histological observations, and enzymatic studies.

Traditional transabdominal and retroperitoneal approaches for paravertebral tumors can be associated with injury to the viscera and lumbar plexus. The authors provide a technical description of a known approach with a new application for the resection of paraspinal tumors using both open and minimally invasive transpsoas techniques and report on 2 illustrative cases. In both cases, gross-total resection of the tumor was achieved and the patients experienced resolution of their presenting neurological symptoms, although one of the patients required 2 extra days of hospitalization due to an asymptomatic retroperitoneal hematoma, which was conservatively managed. The authors conclude that the lateral transpsoas approach is a safe approach for paravertebral tumors and may not require an access surgeon.

BACKGROUND: Symptomatic thoracic disc herniation (TDH) is an uncommon condition with significant treatment risks. OBJECTIVE: To evaluate strategies to avoid and manage complications from thoracic disc surgery. METHODS: All TDH cases by the senior author were retrospectively reviewed from 2000 to 2012. Complications were recorded, together with avoidance and management strategies. To reduce access-related morbidity, a thoracoscopic-tubular retractor approach was developed later in the series. RESULTS: 64 patients were treated for TDH, the majority undergoing an anterior minimally-invasive approach. Complications occurred in 15 patients (23%). Three patients with intercostal neuralgia persisting for >3 months had pain resolution after intercostal nerve blocks and radiofrequency lesioning. Five of the six patients with dural tears during anterior surgery had no further events following dural repair, lumbar drain insertion, and placement of chest tube to water seal. One case of persistent CSF leakage was successfully treated with a laparoscopically-mobilized omental flap. Preoperative metallic marker placement was effective at guiding correct-level surgery. For anterior operations, no pneumothorax occurred with routine chest tube placement. Our approach and techniques evolved based on early experience, allowing us to reduce surgical morbidity. The thoracoscopic-tubular retractor approach was associated with low morbidity (no complications among 13 cases other than temporary intercostal neuralgia). CONCLUSIONS: Several strategies may reduce morbidity from thoracic disc surgery: careful approach selection, preoperative level marking, use a tubular retractor with thoracoscopic guidance, rib resection at the mini-thoracotomy site, routine chest tube placement for anterior operations, and routine lumbar drain insertion in the event of a dural tear. Prospective comparative studies are needed to assess the efficacy of these techniques.

Plantar hyperhydrosis is a disabling condition of excessive, symmetric, focal sweating of the feet with social, psychological, and medical implications. Treatment options include topical agents, iontophoresis, botulinum toxin injection, and surgical disruption of the lumbar sympathetic chain. Surgical corridors include transperitoneal and retroperitoneal approaches. We report our technique with a novel minimally invasive lateral retroperitoneal approach commonly used for lateral interbody fusions. The lateral approach for sectioning of the sympathetic chain in the treatment of hyperhydrosis appears safe. The approach may be advantageous for the patient and surgeons familiar with lateral interbody fusion. Further studies may elucidate the long term efficacy and safety of the lateral approach. The video can be found here: http://youtu.be/Q82SGpmAXng .

OBJECT: Thoracic idiopathic spinal cord herniation (TISCH) is a rare neurological disorder characterized by an incarceration of the spinal cord at the site of a ventral dural defect. The disorder is associated with clinical signs of progressive thoracic myelopathy. Surgery can withhold the natural clinical course, but surgical repair of the dural defect bears a significant risk of additional postoperative motor deficits, including permanent paraplegia. Intraoperative online information about the functional integrity of the spinal cord and warning signs about acute functional impairment of motor pathways could contribute to a lower risk of permanent postoperative motor deficit. Motor evoked potential (MEP) monitoring can instantly and reliably detect dysfunction of motor pathways in the spinal cord. The authors have applied MEPs during intraoperative neurophysiological monitoring (IOM) for surgical repair of TISCH and have correlated the results of IOM with its influence on the surgical procedure and with the functional postoperative outcome. METHODS: The authors retrospectively reviewed the intraoperative neurophysiological data and clinical records of 4 patients who underwent surgical treatment for TISCH in 3 institutions where IOM, including somatosensory evoked potentials and MEPs, is routinely used for spinal cord surgery. In all 4 patients the spinal cord was reduced from a posterior approach and the dural defect was repaired using a dural graft. RESULTS: Motor evoked potential monitoring was feasible in all patients. Significant intraoperative changes of MEPs were observed in 2 patients. The changes were detected within seconds after manipulation of the spinal cord. Monitoring of MEPs led to immediate revision of the placement of the dural graft in one case and to temporary cessation of the release of the incarcerated spinal cord in the other. Changes occurred selectively in MEPs and were reversible. In both patients, transient changes in intraoperative MEPs correlated with a reversible postoperative motor deficit. Patients without significant changes in somatosensory evoked potentials and MEPs demonstrated no additional neurological deficit postoperatively and showed improvement of motor function during follow-up. CONCLUSIONS: Surgical repair of the dural defect is effected by release and reduction of the spinal cord and insertion of dural substitute over the dural defect. Careful monitoring of the functional integrity of spinal cord long tracts during surgical manipulation of the cord can detect surgically induced impairment. The authors' documentation of acute loss of MEPs that correlated with reversible postoperative motor deficit substantiates the necessity of IOM including continuous monitoring of MEPs for the surgical treatment of TISCH.

BACKGROUND: The surgical treatment of lumbar stenosis traditionally includes laminectomy for direct decompression of the spinal canal. Selected patients with spinal stenosis may also require lumbar fusion. Minimally invasive lateral transpsoas interbody fusion has the ability of placing a large interbody cage that can increase disc height and distract the spinal level. The purpose of this study was to examine the concept of indirect decompression of the spinal canal in patients with co-existing lumbar spinal stenosis undergoing lateral transpsoas interbody fusion. MATERIALS AND METHODS: We reviewed 25 consecutive spinal stenosis patients with instability undergoing lateral transpsoas interbody fusion without laminectomy. All patients had relevant symptoms of back pain, leg pain, and/or spinal claudication and met standard criteria for lumbar fusion. Patients were evaluated by outcome analysis scales (VAS scores, Oswestry disability index and treatment intensity scale). Postoperative MRI scans, when available, were evaluated for change in canal dimensions. Statistical significance was assessed by paired t-test, which compares the mean change. There were 25 patients in the study (mean age 61 years). 15 patients had grade I spondylolisthesis. VAS for back pain intensity improved from 7.74 to 2.07 and for frequency from 7.91 to 2.22. VAS for leg pain intensity improved from 7.24 to 1.87 and frequency from 7.41 to 2.35. All improvements were statistically significant (P<0.0001). The Oswestry disability index improved from 55.1 to 16.4 (P<0.0001), and treatment intensity scale improved from 14.6 to 3.7 (P<0.0001). Radiographic evaluation in 20 treated levels (15 patients) found an increase in dural sac dimension of 54% in the anterior-posterior plane and 48% in the medial-lateral plane (P<0.0001). The calculated area of the dural sac increased an average of 143% (range of - 10.4% to + 495%). CONCLUSION: Indirect decompression of spinal stenosis can be achieved with lateral transpsoas interbody fusion with improved clinical outcomes. Pre-op and post-op MRI scans showed a significant increase in dural sac dimensions. The mechanism for this indirect decompression may relate to stretching and unbuckling of the spinal ligaments and a decrease in intervertebral disc bulging. Further studies are needed to determine which stenosis patients undergoing this surgery are most appropriate for indirect decompression alone over laminectomy.

BACKGROUND:: Several approaches have been proposed for the treatment of thoracic disc herniations. Posterior approaches include transpedicular, costotransversectomy, and lateral extracavitary; anterior approaches include Retropleural and Trans pleural thoracotomy and thoracoscopy. OBJECTIVE:: We present a novel minimally invasive approach to thoracic discectomies, combining thoracoscopy and a tubular retractor system. We discuss the utility and safety of this technique. METHODS:: The patient is placed in a lateral decubitus position, with a double lumen endotracheal tube for single lung ventilation. Using thoracoscopic techniques the disc space is identified; approximately 2 cm of the head and neck of the rib is removed to expose the pedicle of the lower vertebral body. The tubular retractor is deployed with continuous thoracoscopic visualization and a trough is created anterior to the canal by drilling the adjacent vertebral bodies straddling the disc space. The operative microscope is utilized to dissect the disc pulling it anteriorly into the trough. RESULTS:: There were 5 patients in the last 9 months who were candidates for anterior thoracic discectomy. Disc herniations from T3-4 to T10-11 were treated, without any significant complications. Patients were followed clinically and radiographically. CONCLUSION:: Combining thoracoscopy with the tubular retractors allows continuous monitoring of the lung, aorta, and vena-cava during the placement of the retractors. Additionally, using the tubular retractors as opposed to a complete thoracoscopic discectomy reduces the working distance and allows the use of the microscope with three-dimensional visualization, thus enhancing the safety of this approach

The management of adult patients with Chiari malformation associated with syrinx remains controversial. Although an abundance of literature exists for the pediatric population, there is an absence of guidelines for the adult population. It is unclear which of the different surgical approaches is appropriate in patients with Chiari I malformations and syringomyelia. A 36-year-old female patient had a posterior fossa decompression 3years prior to recurrence. The patient developed recurrent symptoms with sensory loss and hyperesthesia in the right upper extremity. MRI revealed decreased cerebrospinal fluid flow at the craniocervical junction. The patient was taken to the operating room for revision of the posterior fossa decompression, lysis of adhesions and duraplasty. Re-exploration of a Chiari decompression, lysis of adhesions and revision duraplasty is an effective treatment option for recurrent syringomyelia