Microsurgical treatment of symptomatic sacral Tarlov cysts.

OBJECTIVE: Providing relief of symptomatic radiculopathy resulting from sacral perineural cysts has proven difficult. Our goal was to improve the treatment of these cysts with microsurgical cyst fenestration and imbrication, while minimizing functional damage to neural tissues. METHODS: We retrospectively reviewed the records for eight adult patients with large (2-3-cm) sacral perineural cysts who were treated at the University of California, San Francisco, between October 1992 and April 1999. All patients presented with radicular pain that was refractory to medical treatment. Three patients also reported urinary incontinence. We performed sacral laminectomies with microsurgical cyst fenestration and cyst imbrication for all patients, using intraoperative electromyography to minimize damage to the sacral nerve roots. For seven patients, we reinforced the closures with epidural fat or muscle grafts and fibrin glue application. For five patients with cysts that communicated with the subarachnoid space in computed tomographic myelograms, we placed lumbar drains for cerebrospinal fluid diversion for several days postoperatively. We assessed outcomes, using telephone questionnaires and periodic postoperative physical examinations, 3 to 73 months after surgery. RESULTS: After surgery, radicular pain improved markedly for four patients and moderately for three patients; one patient with initial improvement experienced pain recurrence 9 months later. Bladder control improved markedly for two of the three patients with bladder dysfunction. There were no cerebrospinal fluid leaks and no new postoperative neurological deficits. CONCLUSION: Microsurgical cyst fenestration and imbrication are effective treatments for long-term relief of refractory painful radiculopathy and urinary incontinence associated with large sacral perineural cysts.

Pseudomeningocele/CSF fistula in a patient with lumbar spinal implants treated with epidural blood patch and a brief course of closed subarachnoid drainage. A case report.

STUDY DESIGN: This case report illustrates the development of a cerebrospinal fluid fistula and pseudomeningocele in a patient after lumbar discectomy and fusion with instrumentation. OBJECTIVE: The patient is treated successfully with a combined treatment protocol of epidural blood patch and brief course of spinal drainage. SUMMARY OF BACKGROUND DATA: Many surgeons advocate a trial of cerebrospinal fluid diversion for postoperative cerebrospinal fluid fistula. This treatment may be problematic in patients with spinal implants because a trial of cerebrospinal fluid diversion may not obliterate the extradural anatomic dead space that is created by instrumentation procedures and increases the rist of infection. A few case reports indicate that epidural blood patch also may be an effective management technique. A combined treatment protocol that may offer some advantages to either treatment alone is described METHODS: The patient was brought to the radiology department, and a lumbar spinal drain was placed at the L2-L3 interspace under fluoroscopic guidance with the patient in the prone position. A Tuohy needle was inserted into the pseudomeningocele, and the collection was drained. Thirty milliters of blood drawn from an antecubital vein was injected into the epidural space over the laminectomy site. Spinal drainage was continued for 4 days. RESULTS: The treatment protocol resulted in resolution of cerebrospinal fluid leakage in the patient. This result was confirmed by myelogram. CONCLUSIONS: Postoperative pseudomeningocele and cerebrospinal fluid fistula in patients with spinal instrumentation can be treated successfully with epidural blood patch and a brief course (4 days) of spinal drainage. This combined treatment protocol may have some advantages to treatment with 7 days of cerebrospinal fluid diversion or to percutaneous epidural blood patch alone.

Cervical spondylosis. An update.

Cervical spondylosis is caused by degenerative disc disease and usually produces intermittent neck pain in middle-aged and elderly patients. This pain usually responds to activity modification, neck immobilization, isometric exercises, and medication. Neurologic symptoms occur infrequently, usually in patients with congenital spinal stenosis. For these patients, magnetic resonance imaging is the preferred initial diagnostic study. Because involvement of neurologic structures on imaging studies may be asymptomatic, consultation with a neurologist is advised to rule out other neurologic diseases. In most cases of spondylotic radiculopathy, the results of conservative treatment are so favorable that surgical intervention is not considered unless pain persists or unless there is progressive neurologic deficit. If indicated, a surgical procedure may be done through the anterior or posterior cervical spine; results are gratifying, with long-term improvement in 70% to 80% of patients. Cervical spondylotic myelopathy is the most serious and disabling condition of this disease. Because many patients have nonprogressive minor impairment, neck immobilization is a reasonable treatment in patients presenting with minor neurologic findings or in whom an operation is contraindicated. This simple remedy will result in improvement in 30% to 50% of patients. Surgical intervention is indicated for patients presenting with severe or progressive neurologic deficits. Anterior cervical approaches are generally preferred, although there are still indications for laminectomy. Surgical results are modest, with good initial results expected in about 70% of patients. Functional outcome noticeably declines with long-term follow-up, which raises the question of whether, and how much, surgical treatment affects the natural course of the disease. Prospective randomized studies are needed to answer these questions.

A comparison of fluoroscopy and computed tomography-derived volumetric multiple exposure transmission holography for the guidance of lumbar pedicle screw insertion.

Holographic technology has recently been modified in such a manner that it may now provide clinical use. It allows the visualization of complex structures in three dimensions and permits clinician interaction with the image, which, in turn, provides significant additional geometric and anatomic information. To objectively assess the potential clinical applicability of holography in pedicle screw placement, we studied 11 elderly human cadavers. All of the cadavers, each of which showed significant degenerative disease of the lumbar spine, underwent thin-section computed tomographic scans of the lumbar spine. The acquired digital information was processed, and volumetric multiple exposure transmission holographic images were rendered. Pedicle screws were passed into anatomically acceptable and radiographically visualized L3-L5 pedicles in each cadaver, half using fluoroscopic guidance and half using holographic guidance alone. The accuracy of screw placement was objectively assessed by a three-point grading scale. The total score for the placement of each pedicle screw was determined by both trajectory (location within the pedicle) and accuracy (containment within the vertebral body) of screw tip placement parameters. Three points were possible for each screw placed. Screw placement in the last six cadavers was individually timed for each technique, and fluoroscopic time was also recorded. Each technique was used on 27 pedicles. The total score for fluoroscopic screw placement was 71 (71 of a possible 81; 88%) and for holographic screw placement was 74 (74 of a possible 81; 91%). In the last six cadavers, the screw placement time (per cadaver) was 8 minutes for fluoroscopic placement and 3.6 minutes for holographic placement. Fluoroscopic time averaged 1.9 minutes per cadaver.(ABSTRACT TRUNCATED AT 250 WORDS)

Anatomy of the thoracic pedicle.

Thoracic pedicle anatomy (interpedicular distance, transverse and sagittal pedicle widths, transverse and sagittal pedicle angles, and the distance from the axis of the pedicle to the axis of the transverse process) was assessed in 11 cadavers of elderly people. The cadaveric spines were extensively dissected to augment the accuracy of the measurements via caliper and goniometer. The results were compared with those of previous studies that assessed pedicle anatomy with computed tomography, direct measurement, and three-dimensional morphometry. Between the studies, significant differences were found in transverse pedicle width and transverse and sagittal pedicle angles. These morphometric differences may reflect either the diversity of the techniques used to measure the pedicle anatomy or sampling variation. This article presents a previously unreported morphometric finding, the rostral-caudal distance from the thoracic pedicle to the midpoint of the base of the transverse process. At T1, the transverse process is 5.45 +/- 1.2 mm rostral to the pedicle. This relationship gradually changes as the thoracic spine is descended, so that at T12, the transverse process is 6.6 +/- 2.4 mm caudal to the pedicle. Crossover consistently occurs at the T6-T7 region. Although the transverse process is a reliable external landmark for the location of the pedicle in the lumbar spine, this relationship in the thoracic spine is variable and only moderately predictable.

Treatment and survival of low-grade astrocytoma in adults--1977-1988.

A retrospective review of the records of the Division of Neuropathology at the New York University Medical Center between 1977 and 1988 revealed 53 cases of adult supratentorial astrocytomas. Fifty were fibrillary, and three were gemistocytic. Two additional patients had pilocytic tumors and were not included in the study. The majority of patients had either a subtotal (64%) or gross total resection (19%). Biopsy (17%) was performed for deep-seated lesions and for those lesions confined to eloquent cortex. Forty-eight patients (91%) received postoperative radiation therapy. The median survival was 7 1/4 years with a 5-year survival of 64%. Multivariate regression analysis demonstrated that the most important prognosticators for improved survival were young age, absence of contrast enhancement of the original tumor on computed tomography (CT) and the performance status of the patient. Patients with hemispheric tumors died from dedifferentiation into an anaplastic astrocytoma or a glioblastoma multiforme, with a median time to recurrence of 4.5 years from the original surgery. Survival from the time of recurrence was 12 months. Subsequent operations confirmed progression towards malignancy in six of seven (86%) recurrent tumors. CT contrast enhancement of the original tumor was associated with a 6.8-fold increase in risk for later recurrence. Patients with thalamic tumors (six patients) had a poor prognosis with a median survival of less than 2 years. A review of their CT scans suggest that four died of progressive low-grade disease; however, confirmatory autopsy data were available for only one patient. This study supports others that have shown improved survival for adult patients with astrocytomas treated in the CT era.

Elevation of brain norepinephrine concentration after experimental subarachnoid hemorrhage.

Regional brain tissue catecholamine concentrations were measured in 5 control rats and in 10 rats 72 hours after experimental subarachnoid hemorrhage (SAH). Catecholamine levels were determined in the cerebral hemispheres, brain stem, and cerebellum of each animal using a radioenzymatic assay. Three days after SAH, the tissue concentration of norepinephrine (NE) in the cerebral hemispheres was 64% greater than that in control rats (P less than 0.001). NE levels did not change significantly in either the brain stem or the cerebellum. Most if not all of the NE in the brain tissue rostral to the brain stem is derived from neurons that originate in the locus coeruleus (LC). These data may therefore indicate that the LC is activated after SAH. The possible pathophysiological consequences of activation of the LC in relation to delayed cerebral ischemia after SAH will be discussed.

Increased norepinephrine synthesis in the cerebral hemispheres of rats following subarachnoid hemorrhage.

Norepinephrine (NE) was assayed in rat brains 72 h after the creation of an experimental subarachnoid hemorrhage (SAH). NE in the cerebral hemispheres was found to increase by 64% when compared to controls. NE in the brainstem and cerebellum was unchanged. The kinetics of hemispheric NE metabolism were then studied in control and SAH rats. SAH caused a 3-fold increase in NE synthesis and a 44% reduction in turnover time when compared to controls. These results may reflect increased activity of central noradrenergic neuronal pathways in SAH.