Biomedical subjects
Publications and source records attributed to R H Lye.
Benign tumors of the middle fossa components of the trigeminal nerve are rare. The authors describe the case history, radiological investigation, and operative findings of a patient with a large trigeminal neurofibroma of the middle fossa. The unusual mode of presentation is discussed. Valuable information was provided by magnetic resonance imaging prior to successful removal of this tumor.
The authors reviewed 53 consecutive patients who underwent surgical removal of a meningioma within a 10-year period. The removal was graded macroscopically as either a total removal (types I-III) or a subtotal removal (type IV). The patients were observed for an average period of 5.3 years, during which time there was a 9.5% recurrence after type I removals and an 18.4% recurrence after type II. There was regrowth in 20% of the subtotal group. There was no correlation with age or sex, but histology was important. Syncytial tumors tended to recur, and mitosis and area of focal necrosis were associated with a tendency towards recurrence. The significant features associated with recurrence are discussed.
Basilar artery ectasia may be associated with trigeminal neuralgia as a consequence of trigeminal nerve compression by the aberrant artery. The case histories are presented of four patients, investigation of whom demonstrated the presence of an ectatic basilar artery thought to be the cause of facial pain. The value of intravenous digital subtraction angiography in the investigation of this condition is emphasised. The surgical management is discussed with particular reference to the choice between percutaneous thermocoagulation and posterior fossa microvascular decompression.
The authors reviewed a consecutive series of 115 patients who underwent common carotid ligation during the period 1954-1984. Average follow-up was 10 years. Seventy-three (63%) patients presented following a subarachnoid haemorrhage (SAH) and 42 (36%) presented with the mass effect of an unruptured aneurysm. Thirty-nine (34%) patients were lost to follow-up of whom 27 had had a previous SAH. Forty-six (63%) of the 73 patients traced had suffered a SAH and amongst this group, 11 patients (24%) died from a proven or suspected recurrent haemorrhage within 10 years of ligation. The fatal recurrent haemorrhage rate was, therefore, 2.4%/year. Thirty (71%) of the 42 patients who presented with unruptured aneurysms were traced. Seven of these (23%) died: two following haemorrhage, 1 year and 16 years after carotid ligation and three patients died as a direct consequence of carotid ligation. Check angiographic studies were available for 55 patients following carotid ligation, a mean of 8.4 years after the procedure. Thirteen were conventional angiograms and 42 were intravenous angiograms obtained using the digital subtraction technique. Seventy-six per cent of the aneurysms visualised on the initial studies were either smaller or had apparently disappeared. Only four new aneurysms were detected and in two of these instances, the initial angiographic studies had been incomplete. The authors conclude that the annual rate of fatal recurrent haemorrhage from an intracranial aneurysm following common carotid ligation is of a similar magnitude to that of the natural history of conservatively managed ruptured intracranial aneurysms. Moreover, carotid ligation apparently does not prevent haemorrhage from a previously unruptured aneurysm and the procedure appears to carry a significant morbidity and mortality, even in patients with an unruptured aneurysm.
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The natural history of symptomatic adult Type I Arnold-Chiari malformation (ACM) is variable, and the value of surgery in the management of this disease is difficult to assess. A series of 71 patients in whom a diagnosis of Type I ACM was confirmed at operation is presented, and the progress of the patients following posterior fossa decompression is analyzed. The length of history varied greatly. Pain was the commonest symptom (69% of patients); other symptoms included weakness (56%), numbness (52%), and unsteadiness (40%). The presenting physical signs consisted of a foramen magnum compression syndrome (22%), central cord syndrome (65%), or a cerebellar syndrome (11%). Myelography was performed in 69 patients, and was the most useful investigation. Only 23% of plain radiographs were abnormal. In addition to tonsillar descent, the operative findings included arachnoid adhesions (41%) and syringomyelia (32%). All patients underwent suboccipital craniectomy and C1-3 laminectomy. Respiratory depression was the most frequent postoperative complication (14%), and one patient died from sleep apnea. Early postoperative improvement of both symptoms (82%) and signs (70%) was followed by later relapse in 21% of patients, showing an initial benefit following surgery. None of the patients with a cerebellar syndrome deteriorated, whereas 56% of patients with evidence of foramen magnum compression and 66% of those with a central cord syndrome maintained their initial improvement. The authors conclude that posterior fossa decompression appears to benefit some patients, although a significant proportion might be expected to relapse within 2 to 3 years after operation, depending upon the presenting syndrome.
The authors present the case history of a patient in whom the peritoneal catheter of a ventriculoperitoneal shunt system caused ureter obstruction. This is a rare complication of such a shunt procedure, and the patient's symptoms were relieved by shortening the peritoneal catheter.
Experiments were performed to determine the effects of fibrin-fibrinogen degradation products on the human basilar artery in vivo. Citrated plasma and streptokinase were incubated at 37 degrees C to produce a preparation of fibrinogen degradation products. Aliquots of the incubate were obtained at 90 minutes, 48 hours, and 1 and 2 weeks after preparation, and were separated into fractions of different molecular weight (MWt), using an ultrafiltration technique. Each fraction was tested at each of the above times for contractile activity and possible interaction with a threshold concentration of 5-hydroxytryptamine (5-HT) on the human basilar artery. Contractile activity was initially confined to the 90-minute aliquot fraction MWt greater than 100,000, but as the incubation proceeded, such activity was also seen in the lower MWt fraction less than 100,000 greater than 10,000 at all time intervals. This activity was never seen in the fraction MWt less than 10,000 at any time. Enhancement of the 5-HT response was initially confined to the higher molecular weight fractions, but after 48-hour incubation all fractions showed this activity. It is suggested that products of fibrin-fibrinogen degradation may be involved directly or indirectly in influencing the pathophysiological mechanism(s) responsible for cerebral arterial spasm following subarachnoid hemorrhage.
A series of 33 patients with 35 acoustic nerve tumors is reviewed. Tumor size was estimated from computerized tomography (CT) scans, and its influence on anatomical and functional preservation of the facial nerve was assessed. Six tumors (one invading the petrous bone, three medium and two large tumors) were not detected on CT scans. The translabyrinthine approach was used in seven instances (one small and six medium tumors) and the suboccipital transmeatal approach for 28 tumors (seven medium and 21 large tumors). Anatomical preservation of the facial nerve was achieved in 83% of operations for tumor removal, two of which were subtotal. A further two patients underwent subtotal removal, but the facial nerve was destroyed. Large tumors carried an increased risk of damage to the facial nerve, but even in this group the nerve was preserved anatomically intact in 70% of cases. Damage to the facial nerve occurred more frequently in patients with preoperative evidence of facial weakness; however, this factor did not appear to influence functional recovery of the facial nerve, provided that the nerve was intact at the end of the operation. A simple grading system for facial nerve function is described. Ony 76% of anatomically intact facial nerves showed any evidence of function 1 month after surgery. Postoperatively, facial function improved with time. At the latest review, 45% of these patients had normal facial function or mild facial weakness (Grades I and II).
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The risk of delayed intracranial abscess formation following excision of an occipital dermal sinus or cyst is illustrated by three recent cases. Once suspected, posterior fossa epidermoid and dermoid cysts are readily diagnosed by CT scanning.
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