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Antibiotic neurotoxicity

Laboratory and clinical study

Martin H. Weiss, Theodore Kurze, and Frank E. Nulsen

✓ By ventriculocisternal perfusion, a series of newer antibiotics were circulated through the central nervous system to ascertain the potential toxicity of these drugs to the nervous parenchyma. Ampicillin, carbenicillin, gentamycin sulfate, and polymyxin B sulfate appear to be well tolerated whereas cephalexin monohydrate and penicillin G caused a repeated pattern of significant CSF pleocytosis, histological evidence of periventricular perivascular infiltrates, and evidence of clinical toxicity. A regime for treatment of central nervous system infections is presented, derived from the data presented above. Preliminary experience in a clinical series appears to support this program.

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Sixth nerve schwannomas

Report of two cases

Howard Tung, Thomas Chen, and Martin H. Weiss

✓ Two cases of sixth cranial nerve schwannoma are presented with a review of four other cases from the literature. The clinical spectrum, neuroradiological findings, and surgical outcome of the six cases are discussed. There are two distinct clinical presentations for sixth cranial nerve schwannomas. Type I sixth nerve schwannomas present with sixth nerve palsy and diplopia and arise from the cavernous sinus. In contrast, type II sixth nerve schwannomas have a more severe presentation with obstructive hydrocephalus, raised intracranial pressure, sixth nerve palsy, and diplopia. This type arises along the course of the sixth cranial nerve in the prepontine area. Cavernous sinus involvement in either type may preclude total surgical excision and indicate an increased possibility for recurrence.

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Selective radionecrosis of the choroid plexus for control of experimental hydrocephalus

Martin H. Weiss, Frank E. Nulsen, and Benjamin Kaufman

✓ Hydrocephalic dogs treated with intraventricular radioactive colloidal gold showed a sustained decrease in cerebrospinal fluid flow and intraventricular pressure associated with a reversal of progressive hydrocephalus. Gamma scanning and isotopic sampling, however, indicated a more diffuse distribution of the isotope than previously thought, although pathological changes up to 7 weeks post-instillation of the radioactive colloid appeared confined to the choroid plexus.

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Optic Canal Enlargement

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Cushing disease

Edward H. Oldfield

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Development of neurosurgery in Southern California and the Los Angeles County/University of Southern California Medical Center

John H. Schneider, Martin H. Weiss, and William T. Couldwell

✓ The Los Angeles County General Hospital has played an integral role in the development of medicine and neurosurgery in Southern California. From its fledgling beginnings, the University of Southern California School of Medicine has been closely affiliated with the hospital, providing the predominant source of clinicians to care for and to utilize as a teaching resource the immense and varied patient population it serves.

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Long-term neurological, visual, and endocrine outcomes following transnasal resection of craniopharyngioma

Indro Chakrabarti, Arun P. Amar, William Couldwell, and Martin H. Weiss

Object. The authors report on a cohort of patients with craniopharyngioma treated principally through transnasal (TN) resection and followed up for a minimum of 5 years. More specifically, they evaluate the role of the TN approach in the management of craniopharyngioma.

Methods. Between 1984 and 1994, 68 patients underwent TN resection of craniopharyngiomas at the University of Southern California. The tumor was at least partially cystic in 88% of cases. Four tumors were purely intrasellar, 53 had intra- and suprasellar components, and 11 were exclusively suprasellar. During the same period, 18 patients underwent transcranial (TC) resection of purely suprasellar craniopharyngiomas. Long-term neurological, visual, and endocrine outcomes were reviewed for all patients.

In 61 (90%) of 68 patients in the TN group, total resection was achieved, according to 3-month postoperative magnetic resonance images, although four patients suffered a recurrence. Three (43%) of the seven tumors that had been partially resected were enlarged on serial imaging. Fifty-four (87%) of 62 patients with preoperative visual loss experienced improvement in one or both eyes, but two patients (3%) with exclusively suprasellar tumors experienced postoperative visual worsening in one or both eyes. New instances of postoperative endocrinopathy (that is, not present preoperatively) occurred as follows: hypogonadism (eight of 22 cases), growth hormone (GH) deficiency (four of 18 cases), hypothyroidism (11 of 49 cases), hypocortisolemia (nine of 52 cases), and diabetes insipidus (DI; four of 61 cases). One case each of hypocortisolemia and hypothyroidism resolved after surgery. Hyperphagia occurred in 27 (40%) of 68 patients. One patient had short-term memory loss. Postoperative complications included one case of cerebrospinal fluid leak.

Among the 18 patients in the TC group, 11 had complete resections. In one case (9%) the tumors recurred. Three (43%) of the seven subtotally resected tumors grew during the follow-up interval. Vision improved in 11 (61%) of 18 cases and worsened in three (17%) as a result of surgery. New instances of postoperative endocrinopathy occurred as follows: hypogonadism (one of six cases), GH deficiency (four of seven cases), hypothyroidism (11 of 14 cases), hypocortisolemia (eight of 15 cases), and DI (nine of 16 cases). No instance of preoperative endocrinopathy was corrected through TC surgery. Four patients (22%) exhibited short-term memory loss and 11 (61%) had hyperphagia after surgery. When compared with those in the TC group, patients in the TN group had shorter hospital stays.

Conclusions. Use of the TN approach can render good outcomes in properly selected patients with craniopharyngioma, particularly when the tumor is cystic. Even in mostly suprasellar cases, an extended TN approach can afford complete resection. Note that endocrine function often worsens after surgery and that postoperative obesity can be a significant problem.

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Septic cavernous sinus thrombosis following transsphenoidal craniotomy

Case report

Federico Sadun, Steven E. Feldon, Martin H. Weiss, and Mark D. Krieger

✓ The authors present a case of late-onset cavernous sinus thrombosis in a 74-year-old man who had undergone transsphenoidal craniotomy for a pituitary macroadenoma 9 weeks previously. The patient developed headache, rapidly progressive ophthalmoplegia, and signs of orbital congestion. After 2 days of ineffective broad spectrum antibiotic therapy he underwent a second transsphenoidal craniotomy for abscess drainage. Intraoperative cultures grew 4+ nonhemolytic Streptococcus, 4+ Staphylococcus coagulase negative, and 4+ Haemophilus influenzae. The patient was maintained on intravenous antibiotic therapy for the following 6 weeks, resulting in a complete clinical recovery.

To the authors' knowledge, this is the first report of a septic cavernous sinus thrombosis following a transsphenoidal craniotomy.

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Assessment of long-term remission of acromegaly following surgery

Mark D. Krieger, William T. Couldwell, and Martin H. Weiss

Object. The criteria for remission of acromegaly following transsphenoidal adenoma resection are in evolution. In the present study the authors evaluate the utility of predicting long-term remission by reference to a single fasting growth hormone (GH) level on the 1st postoperative day.

Methods. A retrospective analysis was conducted on 181 patients with acromegaly who underwent transsphenoidal resection between 1973 and 1990 and completed a 5-year follow-up period. Fasting serum GH levels were obtained in all patients on the 1st postoperative day in the absence of exogenous glucocorticoids. All patients participated in a follow-up evaluation lasting at least 5 years, which included measurements of serum insulin-like growth factor—I (IGF-I) levels as an index of acromegalic activity.

Among the 181 patients, GH levels ranged from 0 to 8 ng/ml in 131 (72%) on the 1st postoperative day, suggesting biochemical remission. This group included 107 (84%) of the 127 patients with microadenomas, but only 24 (44%) of the 54 with macroadenomas. Nevertheless, 15 (11%) of the 131 patients who initially had attenuated GH levels displayed recurrent acromegaly within the first 2 years (with elevated levels of IGF-I in all cases, and abnormalities appearing on magnetic resonance images in nine cases). Only one of 116 patients in whom the initial postoperative GH level was lower than 2 ng/ml experienced a recurrence, whereas 14 (93%) of the 15 patients with postoperative GH levels between 2.2 and 8 ng/ml subsequently displayed biochemical evidence of acromegaly.

Conclusions. The findings indicate that a fasting morning serum GH level lower than 2 ng/ml on the 1st postoperative day portends long-term biochemical remission of acromegaly, whereas higher levels are a significant marker for recurrent disease.

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Experiences with sterilization of the operating microscope

Theodore Kurze, Michael L. J. Apuzzo, Martin H. Weiss, and James S. Heiden

✓ Experiments were conducted to assess the feasibility of both paraformaldehyde and ethylene oxide gas sterilization of the operating microscope. From these experiments and practical experience, it is concluded that ethylene oxide sterilization of the operating microscope is a feasible and desirable alternative to cumbersome draping techniques.