Citations

It is currently unclear whether aging alters the perfusion of active muscles during large-muscle dynamic exercise in humans. To study this issue, direct measurements of leg blood flow (femoral vein thermodilution) and systemic arterial pressure during submaximal cycle ergometry (70, 140, and 210 W) were compared between six younger (Y; 22–30 yr) and six older (O; 55–68 yr) chronically endurance-trained men. Whole body O2uptake, ventilation, and arterial and femoral venous samples for blood-gas, catecholamine, and lactate determinations were also obtained. Training duration (min/day), estimated leg muscle mass (dual-energy X-ray absorptiometry; Y, 21.5 ± 1.2 vs. O, 19.9 ± 0.9 kg), and blood hemoglobin concentration (Y, 14.9 ± 0.4 vs. O, 14.7 ± 0.2 g/dl) did not significantly differ ( P > 0.05) between groups. Leg blood flow, leg vascular conductance, and femoral venous O2 saturation were ∼20–30% lower in the older men at each work rate (all P < 0.05), despite similar levels of whole body O2 uptake. At 210 W, leg norepinephrine spillover rates and femoral venous lactate concentrations were more than twofold higher in the older men. Pulmonary ventilation was also higher in the older men at 140 (+24%) and 210 (+39%) W. These results indicate that leg blood flow and vascular conductance during cycle ergometer exercise are significantly lower in older endurance-trained men in comparison to their younger counterparts. The mechanisms responsible for this phenomenon and the extent to which they operate in other groups of older subjects deserve further attention.

The need to preserve hearing during acoustic neuroma removal has rekindled interest in labyrinth‐sparing procedures. This review of 11 years' experience with the retrosigmoid approach to acoustic neuroma removal includes 335 procedures in 332 patients. There were no intraoperative deaths; two patients died in the postoperative period. The facial nerve was preserved in 86.3% of procedures, and auditory function was preserved in 45 procedures (34% of those tumors were 2 cm or smaller). Postoperative complications occurred in 101 procedures, the most common being cerebrospinal fluid otorhinorrhea in 40 cases; 25 of these required secondary surgery. Meningitis occurred 16 times and aspiration 8 times; all other complications were less frequent. Tumor removal was incomplete in eight procedures; In only one of these cases has tumor recurred. The six recurrences usually were identified 5 or more years postoperatively. This has prompted us to follow patients for 7 years postoperatively. Major changes in our management include the use of the supine position and of electrophysiologic monitoring. Advantages of the approach are: (1) wide access to the tumor, (2) applicability to all tumor sizes, (3) potential to preserve facial and auditory function in all cases, and (4) ability to change procedure without sacrificing labyrinth. This review confirms our confidence in this approach to acoustic neuroma removal.

Audiologic test results were reviewed for 30 patients whose hearing was preserved following eighth nerve tumor surgery. Speech reception thresholds, 4,000-Hz thresholds, acoustic reflexes, and ABR wave I absolute latencies were generally unchanged or poorer following surgery; word recognition scores were essentially unchanged. By contrast, ABR waves III and V, and the I–III and I–V interpeak intervals, were generally improved postoperatively, including several patients who had clear waves following surgery despite absent preoperative responses. The improved ABR tracings likely indicate increased neural synchrony due to reduced pressure on the cochlear nerve following surgery, whereas the reduced hearing sensitivity probably reflects cochlear damage coincident to the surgery.

We describe four cases of symptomatic pneumocranium, a rare, potentially life-threatening complication of transsphenoidal pituitary surgery. Symptomatic pneumocranium manifested as impaired mental status, headaches, and grand mal seizures, early in the postoperative course after transsphenoidal pituitary surgery. Furthermore, a Cushing response, including systemic hypertension and bradycardia (secondary to intracranial hypertension) was seen, which has not been previously described in association with symptomatic pneumocranium. We describe a previously unreported risk factor for tension pneumocranium, untreated obstructive sleep apnea. Other factors predisposing to tension pneumocranium in our patients included: cerebrospinal fluid leaks, postoperative positive-pressure mask ventilation, large pituitary tumors, and intraoperative lumbar drainage catheters. Surgical drainage of the pneumocranium and repair of any coexistent cerebrospinal fluid leak markedly improved neurologic status. Symptomatic pneumocranium occurring early in the postoperative course after transsphenoidal pituitary surgery is rare, but prompt recognition and treatment of this condition can be life-saving.

Nonaneurysmal perimesencephalic hemorrhage, a distinct form of subarachnoid hemorrhage, is a recently described variant of intracranial hemorrhage. We describe two patients who presented with unusual features of this type of subarachnoid hemorrhage and also two patients who had a perimesencephalic pattern of hemorrhage due to a ruptured posterior circulation aneurysm. The first patient, a 41-year-old woman with perimesencephalic hemorrhage, underwent an exploratory craniotomy because angiography had suggested an anomaly of the basilar tip. No source of hemorrhage could be identified at the time of surgery. The second patient was a 3-year-old boy who presented with opisthotonos and who was found to have a perimesencephalic hemorrhage. Angiography revealed no source for the hemorrhage. The third patient, a 54-year-old man, had a perimesencephalic pattern of subarachnoid hemorrhage from a vertebrobasilar junction aneurysm associated with a fenestration that was missed on the initial angiographic study. The fourth patient, a 43-year-old man, suffered a perimesencephalic pattern of subarachnoid hemorrhage from a small posterior cerebral artery aneurysm, which had not been recognized on two angiograms. These patients elaborate on the clinical spectrum of subarachnoid hemorrhage with a perimesencephalic pattern. First, a negative exploratory craniotomy suggests that the source of nonaneurysmal perimesencephalic hemorrhage may not be arterial. Second, nonaneurysmal perimesencephalic hemorrhage may also occur in children. Finally, the index of suspicion for a posterior circulation aneurysm should remain high in patients who present with a perimesencephalic pattern of subarachnoid hemorrhage, and these aneurysms may rise from unusual locations.

Abstract Fibromatoses are uncommon infiltrative lesions affecting musculoaponeurotic structures, most often of the limbs and trunk. Lesions involving the cranial cavity are rare and require the same aggressive surgical management as elsewhere in the body. This case illustrates their clinical and neuroradiological features and underscores the necessity for aggressive resection to avoid recurrence. The literature is reviewed. (Neurosurgery 29:123-126, 1991)

Abstract Forty-four cases of meningeal hemangiopericytoma that were treated between 1938 and 1987 are reviewed. Fifty-five percent of these tumors occurred in men. The average age of the patients at diagnosis was 42 years. The average duration of preoperative symptoms was 11 months. Symptoms were related to tumor location, which was similar to that of meningioma. The operative mortality was 9% overall, and has been zero since 1974 (18 patients). The average time before the first recurrence was 47 months, with the recurrence rates at 1, 5, and 10 years after surgery being 15, 65, and 76%, respectively. Ten patients have developed extraneural metastasis, mostly to lung and bone, at an average of 99 months after the first operation. The 10- and 15-year rates of metastasis were 33 and 64%, respectively. The average survival period has been 84 months, with survival rates at 5, 10, and 15 years after surgery of 67, 40, and 23%, respectively. The histological diagnosis of the tumor was not related to survival or recurrence and did not change with recurrence. Tentorial and posterior fossa tumors tended to be more lethal. Total tumor resection favorably affected recurrence and survival, as opposed to subtotal resection. Metastasis adversely affected survival, and was followed by death at an average of 24 months after its diagnosis. Radiation therapy after the first operation extended the average time before first recurrence from 34 to 75 months, and extended survival from 62 to 92 months.