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Peter McL. Black

✓ The Peter Bent Brigham Hospital was established in Boston in 1913. The purchase of the site defined what would become one of the largest medical complexes in the world. This hospital was intended to be a university hospital based on the model created by Johns Hopkins University. The pioneering work of Harvey Cushing while at the Peter Bent Brigham Hospital is briefly touched on.

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Idiopathic normal-pressure hydrocephalus

Results of shunting in 62 patients

Peter McL. Black

✓ Of 62 patients given shunts for normal-pressure hydrocephalus of idiopathic type, 46.8% showed some improvement and 27.4% enjoyed virtually complete recovery. The best clinical predictor of good response was the complete triad of memory difficulty, gait disorder, and urine incontinence; 61.2% of patients with this combination of symptoms improved. Gait disturbance alone was also accompanied by improvement in two of three patients. An “obstructive” cisternographic radioisotope pattern was not significantly different from a “normal” pattern in predicting a response to shunting. Computerized tomography (CT) showing large ventricles and little atrophy predicted improvement in 11 out of 13 patients. There were five deaths within 3 months of shunting. The complication rate was 35.4%; subdural collections, shunt malfunction, and postoperative seizures constituted the most frequent complications.

These data suggest that continued investigation for better predictions of shunt response is important, but that in the meantime the clinical pattern and cranial CT pattern are the most satisfactory guides to improvement after shunting.

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Peter McL. Black

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Elizabeth Noll and Peter McL. Black

It has been demonstrated that glial fibrillary acidic protein (GFAP)-positive astrocyte precursors will differentiate in response to application of retinoic acid (RA), whereas GFAP/oligodendrocyte type 2-astrocyte progenitors will be inhibited from differentiating and continue to be mitotically active in the presence of RA. The authors sought to determine if cells taken from glial tumors that were GFAP positive retained the ability to differentiate following application of RA in vitro, as their normal astrocytic counterparts do. Primary cultures of seven astrocytic tumors were observed to have significantly fewer cells following 1 month of continuous exposure to 100 μM RA. Comparisons with sister control cultures indicated that in control conditions the tumor cells had undergone proliferation, whereas the number of cells in the RA-exposed cultures remained closer to the number of cells initially plated. This response to RA was demonstrated to be specific to the astrocytic tumors by virtue of the fact that cultures of normal brain and an anaplastic ependymoma both showed a strong proliferative response to retinoids.

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Peter McL. Black and Paul H. Chapman

✓ In two cases of normal pressure hydrocephalus, the patients suffered transient abducens weakness following a shunting procedure.

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Karl W. Swann and Peter McL. Black

✓ This review examines the incidence, natural history, diagnosis, prophylaxis, and management of deep vein thrombosis (DVT) and pulmonary embolism (PE) in neurosurgical patients. Recent studies estimate the incidence of postoperative DVT detected by fibrinogen scanning in neurosurgical patients to be 29% to 43%. Specific factors that enhance the risk of venous thromboembolism include previous DVT, surgery, immobilization, advanced age, obesity, limb weakness, heart failure, and lower extremity trauma. Clinical diagnosis of venous thromboembolism is unreliable but can be augmented by noninvasive screening tests such as iodine-125-fibrinogen scanning, Doppler ultrasonography, and impedance plethysmography. As prophylactic measures, mini-dose heparin and external pneumatic compression of the legs have decreased the incidence of DVT in clinical studies of neurosurgical patients. However, no prophylactic measure has been convincingly shown to prevent PE in neurosurgical patients. Thrombi involving the popliteal, deep femoral, and iliac veins appear most likely to cause significant PE. Anticoagulation therapy constitutes standard management of DVT and PE; however, in neurosurgical patients the potential for precipitating intracranial or intraspinal hemorrhage may necessitate vena caval interruption. This appears to be an effective alternative to anticoagulation.

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E. Scott Conner, Lorraine Foley and Peter McL. Black

✓ This research was directed at the pathophysiology of normal-pressure hydrocephalus. The experimental method consisted of accurate and simultaneous measurement of the pressure within the ventricle and over the cerebral convexity in cats with hydrocephalus but normal ventricular pressure. Hydrocephalus was induced by the intracisternal injection of kaolin. Prior to the induction of hydrocephalus, the difference between the ventricular pressure and the pressure over the convexity (the transmantle pressure) was small (0.27 ± 0.31 cm saline, mean ± standard deviation). After the induction of normal-pressure hydrocephalus in seven animals, there was a statistically significant elevation of the transmantle pressure to 3.4 ± 3.9 cm saline (p < 0.05, Student's paired t-test). There was no similar increase in animals injected with lactated Ringer's solution. This finding supports the theory that it is the transmantle pressure, and not the ventricular pressure, that is the physiological determinant of ventricular dilatation. The theory explains why hydrocephalus can develop and persist despite normal ventricular pressure.

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Karl W. Swann, Peter McL. Black and Mary F. Baker

✓ The authors present a retrospective analysis of the management of deep vein thrombosis (DVT) and pulmonary embolism (PE) in neurosurgical patients at the Massachusetts General Hospital from January, 1978, through June, 1982. There were 44 cases of DVT and 13 cases of PE. Management modalities included observation only, femoral vein ligation, inferior vena cava clipping, transvenous placement of an inferior vena cava filter or umbrella, and anticoagulation therapy. Six (75%) of eight patients with symptomatic DVT who were managed by observation alone had subsequent pulmonary emboli, and three (38%) died. Femoral vein ligation was followed by PE in one of four cases and led to significant leg swelling in two others. Neither observation alone nor femoral vein ligation can be recommended as routine management options. Partial inferior vena cava interruption with a De Weese clip, Kim-Ray Greenfield filter, or Mobin-Uddin umbrella all successfully prevented pulmonary emboli. The major problem associated with these methods was leg edema, which occurred in 47% of patients with clip placement, 25% with filter placement, and 21% with a Mobin-Uddin umbrella. Anticoagulation therapy was associated with a complication rate of 29% and a mortality rate of 15%. Fatal PE and paradoxical hypercoagulability with gangrene of a lower extremity were the causes of death. In one patient, hemorrhage into a glioblastoma occurred following discontinuation of anticoagulation therapy when the coagulation parameters were normal.

The authors conclude that: 1) management with observation alone of patients with symptomatic DVT places the patient at risk for the development of life-threatening pulmonary emboli; 2) the safety and timing of therapeutic anticoagulation in postoperative neurosurgical patients or patients with tumors is unclear; and 3) partial interruption of the inferior vena cava with a transvenous filter successfully prevents PE and may represent a safer alternative to anticoagulation therapy.

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Michael Schulder, Jay S. Loeffler, Anthony E. Howes, Eben Alexander III and Peter McL. Black

✓ Harvey Cushing performed over 2000 operations on patients with brain tumors, including 832 for gliomas. He implanted radioactive radium needles, known as a “radium bomb,” in a small number of these patients. He was not impressed with the results and did not pursue this method of treatment in a serious way. The authors present here Cushing's little-known experience with brachytherapy and discuss the reasons for his lack of interest in this technique, despite his advocacy of radiotherapy for certain lesions. An interesting perspective is offered for contemporary neurosurgeons involved in the treatment of brain tumors with cranial irradiation.

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Eben Alexander III, Peter McL. Black, Theodore M. Liszczak and Nicholas T. Zervas

✓ Irrigation of the subarachnoid space after aneurysmal subarachnoid hemorrhage (SAH) has been reported to alleviate subsequent arterial vasospasm. The authors have investigated the effect of lavage of the cerebrospinal fluid (CSF) space in the two-hemorrhage canine model of vasospasm. Twelve dogs had basilar cistern lavage with 120 cc of artificial CSF 24 hours after each of two SAH's, and 12 control dogs had two sequential SAH's without intervening lavage of clot. The amount of clot on the ventral brain stem was evaluated at sacrifice and was graded from 0 (no clot) to 4 (maximum clot) to assess the adequacy of clot removal. Dogs that had undergone lavage had a median grade of 1 (range Grade 0 to 2); control dogs had a median grade of 2 (range Grade 1 to 3.5, p < 0.001, Wilcoxon rank sum test), indicating significant reduction of gross clot by lavage. The neurological findings were graded from 0 to 5, based on meningismus, ataxia, paresis, and cranial nerve deficits. No significant differences in neurological grade were found on any day between the two groups.

Satisfactory angiograms were obtained before and 7 days after hemorrhage and were controlled for blood pressure and blood gases; these showed significant spasm in both groups. There was a mean reduction (± standard deviation) of 21.6% ± 16.2% in basilar artery diameter in control dogs, compared to a 28.8% ± 15.1% reduction in dogs with lavage (difference not significant, t-test). There was a strong, but insignificant, trend toward reduction of endothelial desquamation in the basilar and middle cerebral arteries in dogs with lavage compared to control animals (p = 0.06). Corrugation and tearing of the elastica, thickened intima, intimal fibroplasia, vacuolization of the endothelial or smooth-muscle cells, and presence of blood cells in the adventitia occurred similarly in both groups.

It appears that cisternal lavage 24 hours after hemorrhage in this model has no effect on the angiographic, neurological, or most morphological sequelae of SAH, in spite of evidence for removal of clot as seen at sacrifice. Any postulated interaction of clot and vessel resulting in chronic vasospasm must occur before this time. Evaluation of the effect of much earlier lavage (for instance, 1 hour after hemorrhage) may elucidate the point at which vasospasm is instigated after SAH, and help in determining what factors cause vasospasm.