The authors report their experience in the surgical management of small (less than 1.5 cm diameter) acoustic neuromas. Twenty-nine patients were treated. They had suffered symptoms of unilateral eighth nerve dysfunction on average for 37 months. High resolution CT with iv contrast was the primary investigation. In equivocal cases, air meatography was performed. All operations were performed by the senior author (LS). All tumours were totally removed, there were no deaths and all patients had an excellent result. There were 6 complications (CSF leak 3; meningitis 2; deep venous thrombosis 1). The facial nerve was preserved in 26 cases (and functioned adequately in all) and the cochlear nerve in 62%. In 4 cases with hearing pre-operatively, the decibel loss was the same or less post operatively. In 8 cases speech discrimination remained above 35%.

Adolescent↗

PubMed1989

An experimental study of the effect of nimodipine in primate subarachnoid haemorrhage.

Acute subarachnoid haemorrhage was produced in baboons by a transorbital vessel avulsion technique. Half the animals were pretreated with an intravenous infusion of the calcium antagonistic nimodipine, in a dosage comparable with clinical levels. The severity of the haemorrhage, as measured by changes in intracranial pressure, cerebral perfusion pressure, cerebral blood flow and reactivity, and evoked potentials, was not greater in the group receiving nimodipine. Changes in extracellular K+ and pH were much less marked in animals receiving nimodipine. It is suggested that nimodipine (a) has a protective effect at a cellular level against the ionic changes of ischaemia, (b) does not alter the mechanical severity of subarachnoid haemorrhage.

Acute Disease↗

PubMed1989

Trigeminal neuroma. A report of eleven cases.

The clinical features, diagnosis, and management of a series of 11 cases of trigeminal neuroma (four men, seven women; mean age 40 years) are summarized. Symptoms at presentation were generally those of cerebellopontine angle and petrous apex space occupying lesions. Computed tomography scanning and magnetic resonance imaging were found to provide the best preoperative localization of these lesions, allowing better planning of the surgical approach and thereby maximizing tumor exposure, an essential for any attempt at total excision, considering the large size (greater than 3 cm) of these tumors when diagnosed. A retromastoid incision and posterior fossa craniectomy or a combined suprainfratentorial approach was used. Total excision was possible in four cases. In seven cases, a macroscopic clearance was effected (operative mortality nil, excellent outcome occurred in ten of the 11 cases). There has been no clinical evidence of recurrence or ongoing tumor growth despite possibly subtotal excision.

Adolescent↗

PubMed1989

Surgical management of syringomyelia--current results.

A retrospective study of the surgical results of 98 patients with syringomyelia was carried out. As primary surgical management, 38 cases were treated by craniovertebral decompression, 28 cases by craniovertebral decompression with syringotomy, and 22 cases in which Gardner's operation was performed. Primary syringoperitoneal shunt was done on six patients and the other primary procedures were performed on four. As the secondary operation, syringostomy was performed on nine patients and syringoperitoneal shunt on seven. Better results were obtained in patients managed by craniovertebral decompression with syringotomy or Gardner's operation. However, Gardner's operation had a higher mortality rate and a higher incidence of complication. If a second operation was required, syringoperitoneal shunt had a higher rate of stabilization than syringostomy.

Abnormalities, Multiple↗

PubMed1989

Simultaneous recording of tissue PCO2, interstitial pH and potassium activity in the rat cerebral cortex during anoxia and the subsequent recovery period.

Tissue PCO2 (carbon dioxide tension) (PtCO2), interstitial H+ (H+e) and potassium activities (K+e) were monitored in the cerebral cortex of rats during and after 2-3 min of anoxia. Anoxia was associated with systemic hypotension and caused H+e (extracellular hydrogen ion activity) to increase from pH approximately equal to 7.2 to pH approximately equal to 6.5, K+e to rise from approximately equal to 2.4 up to a maximum of approximately equal to 39 mmol/l, and PtCO2 to increase from approximately equal to 52 to approximately equal to 80 mmHg. Lactate increased from 2 to 5 mmol/kg tissue weight during anoxia and did not fall significantly after re-oxygenation for 10 min. A marked relationship existed between changes in PtCO2 and H+e. After re-oxygenation, K+e (extracellular potassium ion activity) and PtCO2 returned to the pre-anoxic level in a few minutes, whereas H+e took approximately equal to 30 min to recover. H+e recovered in a biphasic manner; a rapid decrease lasting approximately equal to 1 min preceded a much slower phase. We propose that the biphasic normalization of H+e after anoxia mainly reflects an initial and rapid washout of CO2 from brain tissue and a subsequent slow elimination of lactic acid occurring via metabolism and removal by the circulation.

Animals↗

PubMed1989

Intracranial pressure changes following primate subarachnoid haemorrhage.

In 29 anaesthetized baboons avulsion of a small intracranial artery was used to produce a subarachnoid haemorrhage, in a closed-skull situation. Intracranial pressure was measured by extradural transducers, and arterial pressure was also measured continuously, with periodic measurements of cerebral blood flow. After haemorrhage there was an immediate fall in cerebral perfusion pressure in nearly all cases, reaching zero in 9 animals. In 18 there was a significant pressor response in the systemic circulation, but perfusion pressure usually remained low in spite of this response. Perfusion pressure recovered after a few minutes in most cases. In the 19 cases where intracranial pressure was measured on both sides, differences occurred in 11, with the higher pressure always on the same side as the haemorrhage. The difference was evident very soon after haemorrhage in 9 cases, and lasted over half an hour in 5 of them. The mechanism of arrest of bleeding was, in most of this series, not that of a zero perfusion pressure. Explanations for this and for the occurrence of differential pressures are discussed.

Animals↗

PubMed1989

Surgical management of hemangioblastoma of the spinal cord: a report of 18 cases.

The cases of 18 patients operated on for hemangioblastoma of the spinal cord were reviewed. There were 11 men and 7 women. (M:F = 1.6:1) and in 15 patients, the onset of spinal symptoms was before the age of 40 years. There were 19 intradural and 2 extradural tumors. The tumor was accompanied by a cyst in 9 patients (50%). There were 6 cases of Lindau's disease, including 3 cases of multiple spinal tumors. Symptoms improved postoperatively in 13 patients. were unchanged in 2, and were aggravated in 3. At the present time, magnetic resonance imaging with gadolinium-diethylene-triamine-pentaacetic acid (Gd-DTPA) enhancement is the most useful tool for precise localization of the tumor and differentiation of any accompanying cyst.

Adolescent↗

PubMed1989

Lumbar extradural arachnoid cyst presenting as a conus lesion in a man aged 77 years.

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Aged↗

PubMed1989

The effect of orthostatic hypotension on cerebral blood flow and middle cerebral artery velocity in autonomic failure, with observations on the action of ephedrine.

Cerebral blood flow (CBF) and middle cerebral artery velocity (MCAv) have been measured using 133xenon washout and transcranial Doppler in ten patients with autonomic failure. Four pure autonomic failure and four multiple system atrophy patients behaved similarly: tilting them sufficiently to induce significant orthostatic hypotension without causing syncopal symptoms led to a significant fall in their mean MCAv, but no change in their mean CBF. These findings suggest that cerebral autoregulation is preserved in autonomic failure, orthostatic hypotension resulting in a reactive vasodilatation which lowers MCAv, reduces vascular resistance, and maintains CBF. Ephedrine helped to correct the orthostatic hypotension, but had no direct effect on CBF. Two siblings with orthostatic hypotension secondary to dopamine-beta-hydroxylase deficiency also had preserved cerebral autoregulation, but ephedrine led to paradoxical hypotension in these patients.

Adult↗

PubMed1989

Mechanisms and treatment in post-traumatic syringomyelia.

The aetiology, pathophysiology, and treatment of post-traumatic syringomyelia is discussed. The data collected from clinical observation, radiodiagnostic methods, and operative findings are illustrated. It is concluded that at least five different processes may contribute to this progressive disease. A deeper understanding of these mechanisms could help in patient management.

Adolescent↗

PubMed1989

The surgical management of glomus jugulare tumours--description of a single-staged posterolateral combined otoneurosurgical approach.

A series of 31 patients harbouring 33 glomus tumours of the skull base were treated by a posterolateral combined otoneurosurgical approach. Seventy-four percent of tumours were totally exercised. Only one case required a 2-staged procedure. Three patients were given postoperative radiotherapy. Twenty-eight patients had a satisfactory result. There were two deaths in the postoperative period, one from intracerebral haemorrhage and the other from left hemisphere infarction. The literature regarding the initial recognition and characterisation of these neoplasms is briefly summarised. Operative management of these challenging lesions is described and discussed in the context of other available techniques.

Adenoma↗

PubMed1989

Cavernous angioma of the thoracic spinal cord with intra- and extramedullary components.

A 31-year-old male presented with a 1 year history of left leg weakness and right leg sensory changes. Myelography revealed a probable intramedullary lesion at T4 and CT confirmed its intramedullary nature. At operation an almost black, firm mass was found projecting from the dorsal aspect of the cord and was totally excised. Histological examination revealed it to be a cavernous angioma.

Adult↗

PubMed1989

Acoustic neuroma: a review of 392 cases.

A retrospective study was made of all operations for acoustic tumour over a 40-year period. A total of 392 cases are reported. Trends over time and with the size of the tumour are reported. In the current decade all but two tumours were completely resected, the mortality rate was 1.4%, 94% of patients had a good or excellent result, the facial nerve was preserved in 64% of cases (90% of these with acceptable function) and the cochlear nerve in 13.5% (some with hearing). There is a striking dependence on the size of the tumour of the likely outcome of operation.

Cochlear Nerve↗