John E. McGillicuddy

Adjacent segment disease after lumbar or lumbosacral fusion: review of the literature.

Study Design. Review of the literature. Objectives. Review the definition, etiology, incidence, and risk factors associated with as well as potential treatment options. Summary of Background Data. The development of pathology at the mobile segment next to a lumbar or lumbosacral spinal fusion has been termed adjacent segment disease. Initially reported to occur rarely, it is now considered a potential late complication of spinal fusion that can necessitate further surgical intervention and adversely affect outcomes. Methods. MEDLINE literature search. Results. The most common abnormal finding at the adjacent segment is disc degeneration. Biomechanical changes consisting of increased intradiscal pressure, increased facet loading, and increased mobility occur after fusion and have been implicated in causing adjacent segment disease. Progressive spinal degeneration with age is also thought to be a major contributor. From a radiographic standpoint, reported incidence during average postoperative follow-up observation ranging from 36 to 369 months varies substantially from 5.2 to 100%. Incidence of symptomatic adjacent segment disease is lower, however, ranging from 5.2 to 18.5% during 44.8 to 164 months of follow-up observation. The rate of symptomatic adjacent segment disease is higher in patients with transpedicular instrumentation (12.2–18.5%) compared with patients fused with other forms of instrumentation or with no instrumentation (5.2–5.6%). Potential risk factors include instrumentation, fusion length, sagittal malalignment, facet injury, age, and pre-existing degenerative changes. Conclusion. Biomechanical alterations likely play a primary role in causing adjacent segment disease. Radiographically apparent, asymptomatic adjacent segment disease is common but does not correlate with functional outcomes. Potentially modifiable risk factors for the development of adjacent segment disease include fusion without instrumentation, protecting the facet joint of the adjacent segment during placement of pedicle screws,fusion length, and sagittal balance. Surgical management, when indicated, consists of decompression of neural elements and extension of fusion. Outcomes after surgery, however, are modest.

Stereotactic navigation for placement of pedicle screws in the thoracic spine

OBJECTIVEPedicle screw fixation in the lumbar spine has become the standard of care for various causes of spinal instability. However, because of the smaller size and more complex morphology of the thoracic pedicle, screw placement in the thoracic spine can be extremely challenging. In several published series, cortical violations have been reported in up to 50% of screws placed with standard fluoroscopic techniques. The goal of this study is to evaluate the accuracy of thoracic pedicle screw placement by use of image-guided techniques. METHODSDuring the past 4 years, 266 image-guided thoracic pedicle screws were placed in 65 patients at the University of Michigan Medical Center. Postoperative thin-cut computed tomographic scans were obtained in 52 of these patients who were available to enroll in the study. An impartial neuroradiologist evaluated 224 screws by use of a standardized grading scheme. All levels of the thoracic spine were included in the study. RESULTSChart review revealed no incidence of neurological, cardiovascular, or pulmonary injury. Of the 224 screws reviewed, there were 19 cortical violations (8.5%). Eleven (4.9%) were Grade II (≤2 mm), and eight (3.6%) were Grade III (>2 mm) violations. Only five screws (2.2%), however, were thought to exhibit unintentional, structurally significant violations. Statistical analysis revealed a significantly higher rate of cortical perforation in the midthoracic spine (T4–T8, 16.7%; T1–T4, 8.8%; and T9–T12, 5.6%). CONCLUSIONThe low rate of cortical perforations (8.5%) and structurally significant violations (2.2%) in this retrospective series compares favorably with previously published results that used anatomic landmarks and intraoperative fluoroscopy. This study provides further evidence that stereotactic placement of pedicle screws can be performed safely and effectively at all levels of the thoracic spine.

Treatment of Patients with Neurological Deficits Associated with Cerebral Vasospasm by Intravascular Volume Expansion

Four patients, including one preoperative patient, developed neurological deficits associated with angiographically proven cerebral vasospasm and were treated with intravascular volume expansion. Indicator dilution techniques were employed to monitor intravascular volume and cardiac functions during treatment. All four patients improved promptly. None of the patients developed cardiac or pulmonary dysfunction despite marked increase in intravascular volume and despite several risk factors such as cardiac symptoms, electrocardiographic abnormalities, and advanced age. The techniques of monitoring and controlling intravascular volume are described. We believe that this is an important therapeutic adjunct for certain aneurysm patients.

MANAGEMENT AND OUTCOMES IN 318 OPERATIVE COMMON PERONEAL NERVE LESIONS AT THE LOUISIANA STATE UNIVERSITY HEALTH SCIENCES CENTER

OBJECTIVE:This study analyzes 318 operative knee-level common peroneal nerve lesions managed at the Louisiana State University Health Sciences Center between 1967 and 1999. METHODS:Each patient was retrospectively evaluated for injury mechanism, preoperative neurological status, electrophysiological studies, lesion type, and operative technique, i.e., neurolysis, suture, or graft repair. All lesions in continuity had intraoperative nerve action potential recordings. RESULTS:There were 141 stretch/contusions without fracture/dislocations (44%), 39 lacerations (12%), 40 tumors (13%), 30 entrapments (9%), 22 stretch/contusions with fracture/dislocations (7%), 21 compressions (7%), 13 iatrogenic injuries (4%), and 12 gunshot wounds (4%). After neurolysis, 107 (88%) of 121 knee-level common peroneal nerve lesions with recordable intraoperative nerve action potentials recovered useful function. Nineteen patients underwent end-to-end suture repair, and 16 (84%) of these achieved good recovery by 24 months. Graft repair was performed in 138 peroneal injuries. Thirty-six patients (26%) had grafts less than 6 cm long, of which 27 (75%) achieved Grade 3 or greater peroneal function. Twenty-four (38%) of 64 patients with 6- to 12-cm grafts, and only 6 (16%) of 38 patients with 13- to 24-cm grafts, attained good peroneal function. Longer grafts correlated with more severe injuries and thus poorer outcomes. Thirty-two (80%) of 40 tumors were resected with preservation of preoperative clinical function. CONCLUSION:Surgical exploration and repair of peroneal nerve lesions achieved good results with timely operations and thorough intraoperative evaluations. Useful function was achieved in 27 (75%) of 36 patients with grafts less than 6 cm in length and in only 88 (44%) of 202 patients with grafts greater than 6 cm in length.

Total en bloc resection of the temporal bone and carotid artery for malignant tumors of the ear and temporal bone

A technique for single stage total en bloc resection of the temporal bone and infratemporal carotid artery with immediate reconstruction has been described. This formidable procedure requires the collaborative efforts of neurotologic skull base surgeons, neurosurgeons, and head and neck surgeons.

Surgical outcomes of 111 spinal accessory nerve injuries.

OBJECTIVEIatrogenic injury to the spinal accessory nerve is not uncommon during neck surgery involving the posterior cervical triangle, because its superficial course here makes it susceptible. We review injury mechanisms, operative techniques, and surgical outcomes of 111 surgical repairs of the spinal accessory nerve. METHODSThis retrospective study examines clinical and surgical experience with spinal accessory nerve injuries at the Louisiana State University Health Sciences Center during a period of 23 years (1978–2000). Surgery was performed on the basis of anatomic and electrophysiological findings at the time of operation. Patients were followed up for an average of 25.6 months. RESULTSThe most frequent injury mechanism was iatrogenic (103 patients, 93%), and 82 (80%) of these injuries involved lymph node biopsies. Eight injuries were caused by stretch (five patients) and laceration (three patients). The most common procedures were graft repairs in 58 patients. End-to-end repair was used in 26 patients and neurolysis in 19 patients if the nerve was found in continuity with intraoperative electrical evidence of regeneration. Five neurotizations, two burials into muscle, and one removal of ligature material were also performed. More than 95% of patients treated by neurolysis supported by positive nerve action potential recordings improved to Grade 4 or higher. Of 84 patients with lesions repaired by graft or suture, 65 patients (77%) recovered to Grade 3 or higher. The average graft length was 1.5 inches. CONCLUSIONSurgical exploration and repair of spinal accessory nerve injuries is difficult. With perseverance, however, these patients with complete or severe deficits achieved favorable functional outcomes through operative exploration and repair.

Sacral and Presacral Tumors: Problems in Diagnosis and Management

We reviewed 9 cases of sacral tumors with presacral extension. These included 2 chordomas, 1 metastatic renal cell carcinoma, 2 schwannomas (1 malignant, 1 benign), 1 neurofibroma, 1 neurofibrosarcoma, 1 aneurysmal bone cyst, and an exceedingly rare meningioma. The sex of the patients was not significant. The age of the patients at diagnosis ranged from 13 to 68 years (mean, 47 years). Initial symptoms of low back and radiating leg pain were present in all but 1 patient. The duration of symptoms prior to diagnosis ranged from 1 month to 9 years (mean, 2.6 years). A delay in diagnosis of 2 years or more occurred in 6 of the 9 patients. Progressive perineal numbness and/or sphincter dysfunction were seen in 6 patients, and a palpable rectal mass was noted in 6 of 9 patients. The efficacy of various diagnostic tests is presented, as are the surgical options--needle biopsy and anterior and posterior approaches. Despite improved radiographic imaging techniques, these unusual tumors are often diagnosed at an advanced stage, and may masquerade as discogenic radiculopathy. Late diagnosis contributes to the difficulty of surgical extirpation. Anterior and posterior surgical approaches involving general, orthopedic, and urological surgeons may be required.

Surgical Management and Results of 135 Tibial Nerve Lesions at the Louisiana State University Health Sciences Center

OBJECTIVEThis retrospective study presents 33 years of clinical and surgical experience with 135 tibial nerve lesions to review operative techniques and their results and to provide management guidelines for the proper selection of surgical candidates. METHODSBetween 1967 and 1999, 135 patients with tibial nerve lesions at the knee level or below were managed surgically at the Louisiana State University Health Sciences Center. We reviewed these cases. RESULTSOf the 135 cases, traumatic injury accounted for 71, tarsal tunnel syndrome for 46, and nerve sheath tumor for 18. Of 22 lesions not in continuity, functional recovery of Grade 3 or better was achieved in 4 (67%) of 6 patients who required end-to-end suture repair and 11 (69%) of 16 patients who required graft repair. One hundred thirteen tibial nerve lesions in continuity underwent primarily external or internal neurolysis or resection of the lesions. A few received end-to-end suture or graft repair. Direct intraoperative recording of nerve action potentials guided case management decisions. Among the 113 patients with lesions in continuity, 76 (81%) of 94 patients receiving neurolysis, 5 (83%) of 6 receiving suture repair, and 11 (85%) of 13 receiving graft repair recovered function to Grade 3 or better. Repair results were best in patients with recordable nerve action potentials treated by external neurolysis. Results were poor in a few patients with very lengthy lesions in continuity and in reoperated patients with tarsal tunnel syndrome. CONCLUSIONSurgical exploration and repair of tibial nerve lesions, including nerve sheath tumors and tarsal tunnel syndromes, achieved excellent outcomes.

Gradual carotid artery occlusion in the treatment of inaccessible internal carotid artery aneurysms

The authors discuss 21 cases of large or surgically inaccessible internal carotid artery aneurysms treated with gradual occlusion of the cervical portion of the internal carotid artery. Eighty-five per cent of the patients experienced relief or marked improvement of their symptoms after treatment. Two early cases developed postligation ischemic deficits that partially resolved. After the introduction of expansion of circulating blood volume and induced hypertension as adjuncts to graded carotid occlusion, no ischemic complications occurred.

Dysphagia due to anterior cervical hyperosteophytosis.

BACKGROUND Anterior cervical hyperosteophytosis describes the excessive formation of osteophytes along the ventral spine. Dysphagia due to ACH is considered an uncommon entity described mainly in case reports. Symptomatic ACH has been attributed to multiple etiologies including DISH, trauma, postlaminectomy syndromes, and cervical spondylosis. We report one of the largest series of patients with ACH-induced dysphagia requiring surgery. METHODS After IRB approval, a retrospective chart review was completed. From 2001 to 2006, 9 patients presented with dysphagia due to ACH requiring surgical treatment. RESULTS Eight patients were male, and the mean age was 65.1 years. Cervical spine x-rays and CT clearly demonstrated ACH in each case. Esophagram or a video fluoroscopic swallowing study was used to verify that dysphagia was caused by osteophytic overgrowth in all instances but one. In 2 patients, a focal osteophyte had formed adjacent to a previously fused segment. Of the remaining 7 patients, osteophytic formation was attributed to cervical spondylosis in 2 patients and DISH in 5 patients. All patients underwent osteophytectomy without spinal fusion. Average follow-up was 9.8 months. Although all 9 patients experienced resolution of dysphagia, improvement was delayed in 2 patients. CONCLUSIONS Diffuse idiopathic skeletal hyperostosis and spondylosis are the most common etiologies accounting for ACH-induced dysphagia. Adjacent segment disease may also be a potential cause of symptomatic ACH and has not been previously reported. Regardless of etiology, surgical resection is highly successful if conservative measures fail.