Head trauma: comparison of MR and CT--experience in 100 patients.

The results of CT and MR imaging were reviewed retrospectively and compared in 100 patients who experienced clinically significant head trauma. The findings were analyzed on the basis of several parameters in an attempt to establish objective clinical guidelines for the use of each diagnostic technique. CT remains the screening method of choice in evaluating acute severe head trauma; however, MR revealed additional clinically relevant findings in all four cases in which the patient's clinical symptoms were disproportionate to the CT findings. MR was equal or superior to CT in the evaluation of all patients with acute minor head trauma and in 94 of 95 patients examined in the subacute, chronic, or remote phase of injury, irrespective of the severity or pathologic nature of their injuries. All subacute contusions (21 lesions) and white-matter shearing lesions (18 cases) were demonstrated to particular advantage on MR compared with CT, as were all subdural hematomas (of 52 small subdural collections, 58% were detected only by MR). Although surgical management was not altered by the additional information provided by MR, the implications regarding the medical management and disposition of the patients with head trauma were significant.

Cerebellopontine angle tumor causing contralateral trigeminal neuralgia: a case report.

A case of trigeminal neuralgia caused by a contralateral acoustic neurinoma is reported. The patient's tic pain was completely alleviated after removal of the tumor. Previously reported cases of trigeminal neuralgia caused by contralateral cerebellopontine angle tumors are reviewed, and the pathophysiology of this disorder is discussed.

Intracranial space-occupying lesions in acquired immune deficiency syndrome patients.

The recent description of the acquired immune deficiency syndrome (AIDS) followed the observation of an increased incidence of unusual neoplasms and opportunistic infections in previously healthy homosexual men, intravenous drug abusers, Haitians, hemophiliacs, and certain infants. Active research efforts on this group of patients established a defect in cellular immunity. Six patients with AIDS who underwent neurosurgical procedures for intracranial space-occupying lesions are presented. Two of the patients had toxoplasmosis brain abscesses, one had primary central nervous system lymphoma, one had cytomegalovirus encephalitis, one had progressive multifocal leukoencephalopathy, and one patient remained undiagnosed despite pathological examination of the brain tissue specimen. We recommend brain biopsy in AIDS patients with space-occupying lesions because the regimen for the various conditions differs. Although the central nervous system diseases found in AIDS patients are associated with a high mortality rate, four of the six patients responded favorably to specific treatment.

Delayed intracerebral hemorrhage after ventriculoperitoneal shunting.

A rare complication of ventriculoperitoneal shunting is presented. In this case, a moderate-sized intracerebral hemorrhage (3 to 5 cm in maximal diameter) occurred 1 week after operation for idiopathic hydrocephalus in a 43-year-old woman. The patient recovered fully without operative intervention. No other case of delayed intracerebral hemorrhage after a ventricular shunting procedure was found in a review of the literature. The presumed mechanism in the present case is delayed erosion of a cerebral blood vessel by the ventricular catheter.

Prolonged lumbar spinal drainage after the resection of tumors of the skull base: a cautionary note.

A combined transcranial and facial approach was used for an en bloc resection of a malignant angiosarcoma of the ethmoid sinuses. The patient awoke neurologically intact and was monitored in the Intensive Care Unit. A lumbar subarachnoid drain was placed for the continuous removal of the cerebrospinal fluid (CSF). Approximately 36 hours after surgery, she deteriorated neurologically and demonstrated bilateral extensor posturing to painful stimuli. A computed tomographic scan demonstrated obliteration of the basal cisterns indicative of transtentorial herniation and a small amount of extradural air. Eight hours after the lumbar drain was turned off, the patient had recovered completely. We propose that the patient manifested transtentorial herniation caused by a pressure gradient between the supratentorial and lumbar cistern compartments brought on by the continuous removal of CSF from the lumbar subarachnoid space. We suggest that ventricular drainage should be considered for these cases rather than lumbar drainage. This offers the same advantage of removing the CSF and maintaining low-to-normal intracranial pressure without the risk of transtentorial herniation.

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.

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.

Comparison of magnetic resonance imaging and computed tomography in the evaluation of head injury.

Thirty-five patients who had incurred head trauma were studied with computed tomography (CT) and magnetic resonance imaging (MRI). CT was performed using a General Electric 8800 scanner. MRI was conducted with a Technicare Teslacon system using a 5.0 kG (0.5 T) magnetic field. Clinically, patients varied from those with mild concussions without focal neurological signs to those with severe neurological dysfunction including posttraumatic coma. MRI was superior to CT in imaging 23 of 41 extracerebral fluid collections, both in estimating the size of the collections and in diagnosing small collections. MRI was also superior to CT in distinguishing chronic subdural hematomas from hygromas. Further, MRI was superior to CT in visualizing nonhemorrhagic contusion in 15 of 21 lesions. Because of the potential failure of MRI to diagnose acute subarachnoid or acute parenchymal hemorrhage, CT remains the procedure of choice in diagnosing head injury less than 72 hours old.

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.

Hypersensitivity reaction associated with sterile ventriculoperitoneal shunt malfunction.

Infection and obstruction remain significant problems associated with shunts. We studied the clinical and pathological findings in 29 patients who underwent surgical procedures to revise malfunctioning ventriculoperitoneal shunts. The preoperative diagnosis for shunt malfunction was infection in 8 cases, and obstruction in 18 cases. A pathologist NK independently examined the shunt hardware removed from the patients without knowledge of the clinical diagnosis. There were 19 ventricular catheters, 15 valves, and 14 abdominal catheters examined. Fourteen of the patients had had three or more shunt revisions. Three of these patients had evidence of some hypersensitivity reaction due to the shunt hardware (multiple eosinophils and giant cells in tissue enveloping shunt hardware). Of the 15 patients who had two or less shunt revisions, none had evidence of hypersensitivity on pathological examination of the shunt hardware. We conclude that pathological examination of shunt hardware is helpful in understanding noninfectious causes of shunt malfunction. We have identified a subgroup of patients who developed a hypersensitivity-like reaction around the shunt that in certain instances may lead to shunt malfunction. It is important to identify these patients for they may be more likely to have multiple episodes of shunt malfunction.

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.

Usefulness of preoperative inferior petrosal vein sampling in Cushing's disease.

Adrenocorticotropic hormone (ACTH) levels from the inferior petrosal sinuses and peripheral veins were measured in 10 patients with Cushing's disease. All patients had normal or indeterminate computed tomography scans. In 9 of the 10 patients the petrosal vein sampling showed a gradient between pituitary ACTH and peripheral ACTH verifying the supposition of pituitary dependent hypercortisolism. In seven cases preoperative ACTH levels lateralized tumor to one side of the gland. In six of these cases tumor was found at that location at surgery. In the seventh case, no tumor was identified at surgery and that half of the gland was resected. Nine patients were cured following transsphenoidal excision of tumor.

Clinical-pathological analysis of failed central nervous system fluid shunts.

Clinical failures of central nervous system fluid shunts remain a vexing problem. Attributed largely to infectious and technical etiologies, it has been hypothesized recently that inflammatory mechanisms may play a role in this clinical phenomenon. In order to obtain morphologic evidence for this hypothesis, a study of failed shunts was performed. Twenty-five of 57 sequentially removed CNS fluid shunt assemblies or components over the course of 18 months contained sufficient intraluminal tissue to allow a histomorphologic assessment. Tissue was removed from either the intraventricular or intraperitoneal portion and examined with routine light microscopical and histochemical techniques to assess the degree of cellularity, composition of the cells, presence of debris, and organisms. Morphologic findings were correlated with the clinical courses and microbiological cultures. Data were analyzed nonparametrically using the chi 2 test. There was a substantially significant association between repeated failures and non-infectious obstructions. Eight demonstrated evidence of active inflammatory processes; and although not statistically significant, the presence in 3 cases of giant cells, macrophages, lymphocytes, and eosinophils all suggestive of a hypersensitivity reaction correlated with the occurrence of culture negative clinical failures. These morphologic findings will stimulate further experimental and clinical research into possible inflammatory mediators of shunt failure.

Cervical laminectomy and foraminotomy as surgical treatment of cervical spondylosis: a follow-up study with analysis of failures.

Ninety patients were followed after undergoing multilevel cervical laminectomy for cervical myeloradiculopathy secondary to cervical stenosis. Follow-up data was obtained by chart review and phone interview for all patients; 20% were examined at follow-up as well; 77% of patients were improved, 13% without change, and 10% worse at follow-up. No patients deteriorated in the immediate postoperative period. Greater than 50% of severely disabled patients had an excellent result, and 78% improved somewhat. It is concluded that cervical laminectomy is an effective procedure for treating patients with cervical spondylosis causing myeloradiculopathy. Reasons for failure of this procedure, although rarely identified on follow-up examination, are reviewed and briefly discussed.

Cranial nuclear magnetic resonance imaging in head trauma.

Nuclear magnetic resonance imaging revealed focal intracranial lesions consisting of extraaxial hematomas or nonhemorrhagic contusions in 3 patients with severe neurological disability following head trauma. In all 3, standard skull radiography and computed tomography had been unremarkable.

Acute intracranial hemorrhage: intensity changes on sequential MR scans at 0.5 T.

Thirty-seven patients underwent MR imaging at 0.5 T within 7 days of a CT-documented intracranial hemorrhage. A total of 57 hematomas were evaluated. Twelve patients underwent serial scanning and 12 patients had multiple hemorrhages into different intracranial compartments. The appearances of the hematomas on spin-echo (SE) images with a short repetition time (TR) of 500 msec and short echo time (TE) of 32 msec (SE 500/32), long TR/intermediate TE (SE 2000/60), and long TR/long TE (SE 2000/120) were carefully evaluated with specific attention to the precise time after ictus. Hematomas showed heterogeneous, complex, rapidly changing intensities. There was a significant amount of variation among patients, especially between the third and seventh days. Hematomas studied between 12 and 24 hr after hemorrhage were mildly hyperintense on short TR scans and markedly hyperintense on long TR (intermediate and long TE) scans (stage I). These findings in acute hemorrhage have received little prior attention. Over the next 1-2 days, hematomas became iso- to mildly hypointense on short TR scans and markedly hypointense on long TR scans (stage II). Hypointensity on long TR scans has previously been described at high field strengths; our communication demonstrates that this phenomenon is seen routinely at intermediate field strengths as well. Hematomas became markedly hyperintense on short TR scans beginning on approximately the fourth day postictus and redeveloped hyperintensity on long TR scans approximately 5-6 days after ictus (stage III). By the end of the first week they were hyperintense on all pulse sequences (stage IV). MR findings on the first day after intracranial hemorrhage (in particular, subtle hyperintensity on short TR scans) probably allow for a specific diagnosis, while the variable, hetergeneous, and rapidly changing intensities noted between days 2 and 7 are often less specific.