Michael H. Lavyne

Retrospective analysis of microsurgical and standard lumbar discectomy.

This report retrospectively evaluates 112 cases of microsurgical lumbar discectomy (MICRO) and 35 cases of standard discectomy (STND) performed by one neurosurgeon using data derived from a questionnaire and from chart review. The total amount of postoperative pain medication consumed and postoperative temperature curves in each group were compared to determine how postsurgical morbidity was affected by the MICRO and STND procedures. At a mean follow-up interval of 12.3 and 41 months, 97% of the MICRO respondents reported a good or excellent outcome. Patients with preoperative symptoms exceeding 6 months returned to work in 9.9 ± 1.7 weeks; this interval decreased to 5.58 ± 0.75 weeks, and overall outcome score improved significantly at 41 months follow-up if symptoms were less than or equal to 6 months in duration before surgery. At 44 months mean follow-up, 88% of the STND respondents reported a good or excellent outcome with no decrease in the return-to-work interval in patients who described symptoms of 6 months or less. Mean postoperative pain medication consumed by MICRO patients was one tenth that of STND patients, and temperature curves showed significant temperature elevations in the STND group when compared with the MICRO group, in which patients remained afebrile throughout the postoperative period. With the limitations of a retrospective study, these data support the conclusion that a microsurgical approach to the lumbar herniated disc provides a more frequent and rapid convalescence than the STND approach.

Colonic perforation by ventriculoperitoneal shunts

Two cases of colonic perforation by a ventriculoperitoneal shunt are presented. One was diagnosed by routine abdominal roentgenograms, the other by instilling metrizamide into the distal shunt tubing. A review of the 32 previously reported cases revealed a mortality of 15%. Bowel perforation from a ventriculoperitoneal shunt should be managed with intravenous antibiotics as well as removal of the shunt. If the patient has a benign abdominal examination and no prior history of abdominal complications from a ventriculoperitoneal shunt then the abdominal catheter can be removed percutaneously. However, in the presence of severe peritonitis, or a previous history of serious abdominal problems from the shunt catheter, such as an infected pseudocyst or other intraabdominal pathology, such as active regional enteritis or an abscess, we recommend laparotomy for removing the catheter with primary closure of the bowel perforation.

Symptomatic spinal epidural lipomatosis after local epidural corticosteroid injections: Case report

OBJECTIVE AND IMPORTANCEnSpinal epidural lipomatosis, which causes symptomatic compression of neural elements, is a well known but uncommon complication of Cushings syndrome. Spinal epidural lipomatosis has been reported frequently in association with chronic systemic corticosteroid therapy, but thus far only one case has been attributed to local epidural corticosteroid injections.nnnCLINICAL PRESENTATIONnWe report another case of symptomatic spinal epidural lipomatosis after epidural corticosteroid injections. This is the first such case documented by magnetic resonance imaging and confirmed with surgical exploration.nnnINTERVENTIONnThe patients symptoms of neurogenic claudication resolved after lumbar laminectomy in the region of previous corticosteroid injections and the removal of epidural fat, which was compressing the thecal sac.nnnCONCLUSIONnThis case should alert clinicians that epidural lipomatosis, which causes symptomatic thecal sac compression, is a possible complication, not only of systemic glucocorticoid therapy, but also of local epidural corticosteroid injections.

Thoracic complications of ventriculoperitoneal shunts: case report and review of the literature.

Thoracic complications of ventriculoperitoneal shunts are rare, but potentially serious. The authors report a case of a drainage of cerebrospinal fluid into the tracheobronchial tree through a peritoneal shunt catheter that migrated into the chest. After injection of contrast material into the shunt, a plain radiograph of the chest revealed a bronchogram. The symptoms resolved after a revision of the shunt. Published case reports of this and other thoracic complications of ventriculoperitoneal shunts are comprehensively reviewed. A classification of such complications into three types is proposed as follows: intrathoracic trauma during placement of a shunt, migration of the peritoneal catheter into the chest (by either a supradiaphragmatic or a transdiaphragmatic route), and pleural effusion accompanying cerebrospinal fluid ascites. The possible mechanisms and contributing factors are discussed.

Subchoroidal trans-velum interpositum approach to mid-third ventricular tumors

Our experience with the subchoroidal, trans-velum interpositum approach to mid-3rd ventricular tumors is reviewed, and our operative technique is described. Excellent exposure of the mid-3rd ventricle is gained by opening the foramen of Monro posteriorly after dividing the septal vein and/or the thalamostriate vein from the ipsilateral internal cerebral vein. There has been no morbidity or mortality in eight successive cases. The principal advantage of this technique is that the fornix is preserved and memory function is not at risk.

Is magnetic resonance imaging useful in guiding the operative approach to large pituitary tumors

Forty-two patients with large pituitary tumors were studied with magnetic resonance imaging scans. Based on the operative findings, the tumors were divided into two groups. Tumors in Group 1 (n = 35) were soft or partially necrotic and were easily removed by suction and curettage. Tumors in Group 2 (n = 7) were firm and required sharp dissection or use of the laser for removal. Tumors were divided into two groups based on the long TR signal: a) isointense in comparison with white matter, or b) hyperintense in comparison with white matter. All 7 firm tumors (Group 2) had an isointense signal on long TR sequences. Thirty-two of 35 soft tumors showed a hyperintense signal on long TR sequences, and 3 an isointense signal. Based on these results, we recommend a transsphenoidal approach for the initial operation in patients with large pituitary tumors. If the tumor is largely isointense on the magnetic resonance imaging scan, we discuss with the patient preoperatively the possibility (70% in this series) that the tumor may be too firm to remove in a single transsphenoidal procedure. In these circumstances, a second, transcranial, procedure may be required to decompress the suprasellar structures adequately.

Postoperative Narcotic Requirement After Microscopic Lumbar Discectomy is Not Affected by Intraoperative Ketorolac or Bupivacaine

Study Design. Prospective, randomized, double-blind study. Objective. To assess the efficacy of ketorolac and bupivacaine in reducing postoperative pain after microsurgical lumbar discectomy. Summary of Background Data. Microsurgical lumbar discectomy often is performed as an ambulatory procedure. Pain, nausea, and urinary retention may delay discharge. It was hypothesized that intraoperative ketorolac or bupivacaine would reduce postoperative pain as measured by morphine demand. Methods. After Institutional Review Board (IRB) approval and informed consent, 30 patients undergoing single-level microsurgical lumbar discectomy under general anesthesia randomly received either intravenous ketorolac, intramuscular bupivacaine, or placebo before wound closure. After surgery, all patients received intravenous, MSO4, patient-controlled analgesia. MSO4 demand was compared between groups at 30 minutes and at 1, 4, 8, 16, 20, and 24 hours after surgery by one-way ANOVA. Pre- and postoperative pain was assessed by using a standard scale and was correlated to postoperative MSO4 demand by Pearson correlation. Significance was assumed at P < 0.05. Results. There were no group differences in age, gender, weight, disc level, preoperative pain, or preoperative use of pain medication. Neither ketorolac nor bupivacaine decreased pain or nausea scores, MSO4 demand, or time to void and ambulation. Preoperative pain was significantly correlated to postoperative narcotic demand (r = 0.46, P < 0.01). Preoperative narcotic or NSAID use was not correlated to either preoperative pain scores or postoperative MSO4 requirement. Conclusions. Neither ketorolac nor bupivacaine decreased the postoperative narcotic requirement in patients undergoing microsurgical lumbar discectomy. Postoperative narcotic requirements are increased in patients who are in severe pain before surgery, regardless of preoperative narcotic use.

Effect of low dose gamma-butyrolactone therapy on forebrain neuronal ischemia in the unrestrained, awake rat.

Low dose gamma-butyrolactone (GBL) therapy alters the natural history of experimental forebrain ischemia in the awake rat. After 30 minutes of four-vessel ischemia, repeated hydrogen cerebral blood flow determinations in awake rats over 72 hours revealed that low dose GBL therapy prevented the development of regional cerebral hyperemia and later the prolonged cerebral hypoperfusion that was experienced by the nontreated controls. Moreover, the low dose GBL-treated group had significantly less neuronal tissue loss than that in comparable brain regions of the nontreated controls. Before the stroke studies, GBL dose-response experiments performed on normal rats indicated that high dose GBL therapy produced seizures, systemic hypertension, metabolic acidosis, hyperthermia, and death.

Craniotomy versus Transsphenoidal Excision of Large Pituitary Tumors: The Usefulness of Magnetic Resonance Imaging in Guiding the Operative Approach

Fifteen patients with large pituitary tumors were studied with computed tomography (CT) and magnetic resonance imaging (MRI). CT was performed using General Electric 8800 and 9800 scanners (General Electric Co., Medical Systems Division, Milwaukee, Wisconsin). MRI was performed utilizing a Technicare superconducting scanner (Technicare, Cleveland, Ohio) at 0.5 tesla. Based on the operative findings, the tumors were divided into two groups. Tumors in Group 1 (n = 12) were described by the surgeon as soft or partially necrotic and easily removed by suction and curettage. Tumors in Group 2 (n = 3) were firm and required sharp dissection or the laser for removal. The tumors were divided into four categories based on MRI signal: (a) isointense with surrounding brain on spin echo (SE) 30 and SE 90, (b) increased signal intensity on SE 30 and SE 90, (c) decreased signal intensity on SE 30 and increased signal intensity on SE 90, and (d) isointense signal on SE 30 and increased signal intensity on SE 90. All three of the firm tumors were isointense with brain on MRI appearance. The tumor consistency (firm vs. soft) was not differentiable on CT scan. The transsphenoidal approach is less satisfactory than craniotomy in cases of firm, fibrous pituitary tumors. Based on our preliminary data, if the MRI signal in the tumor is isointense, then the surgeon should be prepared to deal with a fibrous tumor and might elect a transcranial rather than a transsphenoidal approach.

Intraoperative Localization of Subcortical Brain Tumors: Further Experience with B-Mode Real-Time Sector Scanning

Intraoperative ultrasonography is a potentially useful tool for the neurosurgeon faced with the task of finding and removing small subcortical brain tumors. With the B-mode real-time sector scan equipment now available, satisfactory images of the intracranial contents can be obtained. Others have reported obtaining images by applying the transducer directly to the dura mater or cortex. This carries the risk of pressure damage to the brain. Furthermore, the presence of acoustical noise in the region close to the transducer results in poor image resolution in the superficial region of the cortex. To circumvent these two problems, we have used a saline-filled cylinder placed over the craniotomy site to achieve acoustical coupling. This technique also increases the area of cortex visualized by the pie-shaped beam of the sector scan by separating the transducer from the brain surface.