Biomedical subjects
Publications and source records attributed to W A Buchheit.
This evaluation of proficiency is a comparison of other high performance occupations with neurosurgeons, an attempt to understand the minimal number of cases required for proficiency during both residency training and after, and the effect of human factors.
Lipomas of the cerebellopontine angle are rare, although well described in the literature. A review of the literature with an emphasis on pathogenesis and management is presented.
Syringomyelia has been described frequently in association with various abnormalities of the skull base but rarely with tumors of the skull base. Syringomyelia as a postoperative sequela of surgery of the skull base has not been reported. The authors describe a case of cervical syringomyelia developing after the partial resection of a chordoma and combined conventional and proton beam irradiation. The possible mechanisms causing this abnormality are discussed.
Patients with facial paralysis are often seen in neurosurgical practice. Obtaining full facial symmetry and function after facial nerve damage presents the neurosurgeon with a difficult challenge. Various surgical techniques have been developed to deal with this problem. These include primary nerve repair, nerve to nerve anastomosis, nerve grafting, neurovascular pedicle grafts, regional muscle transposition, microvascular muscle transfers, and nerve transfers. Patient selection, timing of surgery, and details of surgical technique are discussed. The results of hypoglossal-facial anastomosis in 24 patients are described.
This study recognizes recent advances in the understanding of the anatomy and physiology of peripheral nerves at the cellular level. It has reproduced study conditions originally advocated by de Medinaceli and coworkers, with modifications. Eighty-four rats were divided into three groups. Group A underwent sciatic nerve transection and standard perineurial repair. Group B nerves were frozen, severed with a vibrating blade, and reconnected by tubulization with a rubber cuff while bathed in solutions designed to inhibit Ca++-calmodulin activation, maintain colloid osmotic pressure, and mimic ambient electrolytic conditions. Group C underwent a similar procedure as group B, with the rubber cuff replaced by a polyglycolic acid mesh. All animals were randomized and evaluated functionally in terms of a sciatic index. By post-operative day 225, animals of group A recovered 37% of function, group B recovered 74%, and group C recovered 67%. Compound action potential recordings revealed a velocity recovery of 41% in group A, 70% in group B, and 81% in group C. Microscopic evaluation provided evidence for corresponding structural improvement. This new method of nerve repair is uncomplicated, relatively inexpensive, and easily adaptable to other animal models.
Direct therapeutic drainage and intracranial pressure monitoring from the posterior fossa has never been accepted in neurosurgical practice. Potential complications including cerebrospinal fluid leak, cranial nerve palsies, and brain-stem irritation have been a major deterrent. The authors placed a catheter for pressure monitoring in the posterior fossa of 20 patients in the course of posterior fossa surgery: 14 patients with acoustic schwannomas, four with posterior fossa meningiomas, one with cerebellar hemangioblastoma, and one with a solitary cerebellar metastatic lesion. A Richmond bolt was also placed in the frontal area. Continuous monitoring of the supratentorial and infratentorial compartments was performed for 48 hours. During the first 12 hours the posterior fossa pressure was 50% greater than that of the supratentorial space in all patients (p less than 0.01). Over the next 12 hours the supratentorial pressure was 10% and 15% higher than the posterior fossa pressures in all patients, and by 48 hours of monitoring the pressures had equilibrated. There was no mortality or morbidity referable to insertion of the posterior fossa catheter. The conclusions drawn from this study are that: 1) direct monitoring and drainage of the posterior fossa is safe and effective; and 2) within the early postoperative period, the supratentorial pressures failed to reflect what is taking place within the posterior fossa. The implications and advantages of direct posterior fossa monitoring in the postoperative patient are discussed.
Lidoflazine, a piperazine derivative of known selectivity for vascular smooth muscle, was evaluated as a possible agent for prophylaxis of cerebral vascular contraction induced by subarachnoid perfusion with whole blood. Previous studies from this laboratory have indicated its efficacy in preventing basilar artery contraction induced by serotonin. The animals treated with a subarachnoid perfusion of whole blood had a mean 30% reduction in vessel diameter over the control value. Groups that were treated with 0.5 mg/kg of lidoflazine and 1.0 mg/kg of lidoflazine and then perfused with whole blood in the subarachnoid space had reductions in control diameter of 2.8% and 6.8%, respectively. One group treated with 2.0 mg/kg of lidoflazine and then perfused with whole blood actually had an increase in diameter of 6.8% over the control value. Lidoflazine, when administered intravenously at a slow rate, will not adversely lower systemic blood pressure and can prevent the contraction of cerebral vessels when the stimulus for contraction is whole blood within the subarachnoid space.
Five adult patients with 3rd ventricle tumors underwent a transcallosal intraventricular parafornicial approach. Pre- and postoperative cognitive reviews were conducted on all patients. Each review consisted of: a standardized neuropsychological battery, mental status reviews, specific tests for disconnection, and a personality variable, where possible. Computed tomography and magnetic resonance imaging are also presented. The three patients with colloid cysts and the two with oligodendrogliomas showed no significant postoperative cognitive deficits compared to the preoperative review. These additional subtle neuropsychometric measures, along with the methodological advantage of preoperative review, support a parafornicial approach where indicated to preserve cognitive abilities.
Contralateral hearing loss is a very rare complication of acoustic neuroma surgery. A case of immediate postoperative contralateral hearing loss is reported. Possible causes and the pertinent literature are reviewed.
Ten patients with neurosensory hearing loss and computed tomographic (CT) evidence of acoustic neuromas were evaluated with magnetic resonance imaging (MRI). Tumors ranged in size from 0.8 to 3.7 cm. With the use of spin echo pulse sequences, all tumors were identified by MRI and appeared as masses with signal intensities greater than that of cerebrospinal fluid and equal to or greater than that of brain stem. Two patients who previously had undergone operation for acoustic neuromas were evaluated with MRI. In one patient with CT evidence of tumor recurrence, the lesion could not be identified by MRI. MRI holds promise of becoming a primary diagnostic modality for the evaluation of acoustic neuromas.
The authors describe a case of multiple supratentorial intracranial arteriovenous malformations in a patient with a family history of cerebrovascular disease. There was no sign of any other vascular dysplasia. A brief review of this rare entity is given.
The management of frontobasal skull fractures must be dealt with in a multidisciplinary manner. The advent of computed tomography has simplified the emergency radiologic investigation and expedited immediate surgical intervention. The major problem to be dealt with is closure of the frontobasal dura, which we accomplish by using an autogenous fascial graft packed under the frontal lobes and secured basally with autogenous adipose implants. In such contaminated injuries, the use of a triple antibiotic regimen should be considered based on the chance of eliminating resistant organisms.
Explore the source record for details and available documents.
A case of spinal cord compression secondary to an osteochondroma of the vertebral body of T-4 is reported. Computed tomography aided in the display of the lesion and the planning of its resection.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The accuracy of radiographic detection of neurosurgical sponges was measured experimentally. Commercially available sponges were inserted into a cadaver in several paravertebral locations and radiographed. A total of 72 radiographs (90 sponges) were assessed, as well as an equal number of radiographs without sponges. The images were viewed by eight observers, whose responses showed marked variation in both false negatives and false positives; however, the two types of errors were compensatory and all responses were located along the same receiver operating characteristic curve. Mean false-negative and false-positive rates were both about 10%. In addition, false-negative rates varied between 3 and 25% according to the type of sponge.