The authors describe percutaneous radiofrequency (rf) thermocoagulation of the sphenopalatine ganglion used to treat seven patients with sphenopalatine ganglion neuralgia. The procedure was effective in relieving pain, without significant side-effects. All the patients have actually been free of pain during a follow-up of 6-28 months. The surgical technique and the rationale for its use are pointed out.

The effect of trigeminal electrical stimulation on cerebral blood flow has been studied in conditions of normal or reduced cerebral blood flow (CBF). Autologous blood was injected into the subarachnoid space of ten Pittmann-Moore pigs to induce subarachnoid haemorrhage (SAH) accompanied by cerebral blood flow (CBF) reduction. One week later, in six of ten animals, a considerable decrease of CBF was noted as evaluated by means of a recording-system monitoring over the right parieto-temporal calvarium the washout of 133Xenon injected into the internal carotid artery after the external carotid had been clamped. Continuous electrical stimulation of the Gasserian ganglion performed in the six animals with severely induced CBF reduction produced a remarkable cerebrovascular dilation and increase of CBF lasting over 3 h. Electrical stimulation of the Gasserian ganglion produced a similar pattern of vasodilation in six pigs in which no blood was injected and no reduction of CBF was evident. The mechanisms and the anatomical pathways which underlie these results are discussed.

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A case of aqueductal stenosis following mumps infection is reported, to the authors' knowledge the 12th case in the literature. The pathogenetic events are discussed and the literature reviewed.

Spontaneous intracranial hypotension (SIH) is a poorly understood entity resulting from CSF leakage or from venous hypotension causing increased CSF absorption. 1 It causes a range of symptoms from orthostatic headaches to coma. MRI and CT myelography are the investigations of choice in demonstrating CSF leaks as presumed sites of dural defects. CT myelography has traditionally been the first diagnostic tool, but this necessitates lumbar puncture for contrast injection and this is both invasive and of significant risk with infra-tentorial herniation. MR myelography has been shown to have comparable detection rates in nerve root leaks and high cervical retrospinal CSF collections, and superior detection rates in spinal leaks. 2 A diagnostic quandary arose in this patient who had serious contraindications to MRI and CT myelography. The presence of a PPM is widely recognized as a contraindication to MRI due to the risk of harmful arrhythmias and heating or displacement of the device or its leads. In a survey asking radiologists and cardiologists whether they would submit a patient to MRI with a PPM in situ, 97% radiologists responded that they would not, whereas 34% of cardiologists responded that they would under appropriate circumstances. 3 There is now a substantial evidence base providing safety data on a large number of MRI studies with PPMs. The devices for which there is most evidence include those manufactured after 1998, in place for over 6 weeks and without epicardial or abandoned leads. 3-7 The number of PPMs will continue to increase due to an ageing population and increasing indications. However, the number of patients with an expanding range of co-morbidities that will benefit from the diagnostic advantages offered by MRI will also multiply. MRI should only be considered when there is no lower-risk alternative to answer clinical questions essential to patient management. This case highlights the commonly overlooked pathology of SIH and raises awareness of the increasing evidence that PPMs are becoming relative rather than absolute contraindications to MRI.

Computed tomography of 8 cases with West’s syndrome before, during and after ACTH treatment are reported. The scans, performed at the third week of therapy, showed consistent widening of the sulci, cisterns and ventricles in all the patients. Of these, 2 patients underwent ICP monitoring which showed higher than normal values. A return to the normal ICP values in association with the disappearance of the CT findings was observed in both cases. It is concluded that widening of the sulci, cisterns and ventricles are not findings of atrophy, but a condition of initial communicating hydrocephalus, which is in accordance with the hypotheses of Riikonen and Lyen.