John Dutton

The fate of tumour rests following removal of acoustic neuromas: An MRI Gd-DTPA study

The fate of capsular fragments left attached to vital structures at the time of otherwise total tumour removal was studied in 14 of 21 such patients who underwent acoustic neuroma surgery. Imaging using magnetic resonance Gd-DTPA at post-operative intervals of 6 months-12 years (mean 70 months) showed evidence of persistent tumour in half the patients. None of the patients had developed new symptoms and computed tomography had failed to demonstrate tumour recurrence. Persistence of the tumour was more likely if the residual fragments were not cauterized at the time of operation. Four of the seven persisting tumour rests showed evidence of gradual enlargement. The implications for patient management, particularly if an attempt is made to preserve hearing, are discussed.

A clinical, genetic and audiological study of patients and families with bilateral acoustic neurofibromatosis

The neurofibromatoses consist of at least two distinct autosomal dominant hereditary disorders. Neurofibromatosis type 1 (NF1) is due to a lesion on chromosome 17q. Neurofibromatosis type 2 (NF2) is caused by a defect on chromosome 22q. The hallmark of NF2 is the development, in the second and third decades, of bilateral acoustic neuromas. NF1 is characterized by the appearance of café-au-lait spots and neurofibromas in addition to iris hamartomas, or Lisch nodules, of the eye, during the first and second decades. Ten families were personally studied. A total of 16 members were found to be affected with NF2. A protocol for evaluation and review of subjects and relatives of NF2 families is proposed. A team approach, coordinating the expertise of multiple specialties is recommended.

Prostacyclin: a New Treatment for Vasospasm Associated with Subarachnoid Haemorrhage

One of the major problems associated with the treatment of ruptured intracranial aneurysms is the syndrome of late onset ischaemia. Patients so affected deteriorate neurologically and cerebral angiography often shows narrowing of the intracranial arteries, commonly known as vasospasm. Many drugs have been used to treat the condition but with little success. A new group of compounds have come into clinical use recently, the Prostaglandins. One member, Prostacyclin (PGI2 or Epoprostenol) is claimed to be one of the most potent vasodilators known. It was used at Manchester first on an experimental model. An isolated piece of human basilar artery was caused to contract using various agents. Prostacyclin was then used in an attempt to relax the contracted segment of artery. It, surprisingly, caused profound relaxation at very low concentrations of Prostacyclin, yet at higher concentrations it again caused the artery to contract. A literature search suggested this also was seen in the living subject and the crossover occurred at a dosage of 5 ng/kg/min. A limited pilot trial was therefore devised using Prostacyclin at the low concentration of 1 ng/kg/min and used on six patients. Patients were assessed, in the main, for clinical improvement and change in radiological spasm. Clinically, the results exceeded our expectations in that all patients improved, some back to normal. Radiologically, the vasospasm changed but did not revert completely and also unusual extracranial-intracranial anastomoses appeared in the angiograms. In addition, in one patient, cerebral blood flow showed a more than threefold increase. No generalised cardiovascular collapse occurred and no bleeding tendency was observed.