Hypothalamic stimulation in chronic cluster headache: a pilot study of efficacy and mode of action.

We enrolled six patients suffering from refractory chronic cluster headache in a pilot trial of neurostimulation of the ipsilateral ventroposterior hypothalamus using the stereotactic coordinates published previously. After the varying durations needed to determine optimal stimulation parameters and a mean follow-up of 14.5 months, the clinical outcome is excellent in three patients (two are pain-free; one has fewer than three attacks per month), but unsatisfactory in one patient, who only has had transient remissions. Mean voltage is 3.28 V, diplopia being the major factor limiting its increase. When the stimulator was switched off in one pain-free patient, attacks resumed after 3 months until it was turned on again. In one patient the implantation procedure had to be interrupted because of a panic attack with autonomic disturbances. Another patient died from an intracerebral haemorrhage that developed along the lead tract several hours after surgery; there were no other vascular changes on post-mortem examination. After 1 month, the hypothalamic stimulation induced resistance against the attack-triggering agent nitroglycerin and tended to increase pain thresholds at extracephalic, but not at cephalic, sites. It had no detectable effect on neurohypophyseal hormones or melatonin excretion. We conclude that hypothalamic stimulation has remarkable efficacy in most, but not all, patients with treatment-resistant chronic cluster headache. Its efficacy is not due to a simple analgesic effect or to hormonal changes. Intracerebral haemorrhage cannot be neglected in the risk evaluation of the procedure. Whether it might be more prevalent than in deep-brain stimulation for movement disorders remains to be determined.

Nasal dermoid cyst: diagnosis and management of five cases.

Five cases of nasal dermoid cyst are presented. Three out of five cases were settled during childhood. Three presented a mass with a hole on the external nose with recurrent local infections. One case was wrongly referred for a dacryocystitis. The first one was detected during an infection of the cerebral extension and frontal abscess was assessed by CT scan and MRI. Two patients had other associated congenital abnormalities: hypotrophy of the external ear in one case, multiples malformations in an other. Adequate exposure and cosmetic results are sometimes contradictory to define the best surgical approach. Dermoid cysts and sinuses must be completely removed to prevent recurrence. External rhinoplasty and bicoronal approach are the main procedures for removing these lesions.

Minimally invasive endoscopic management of malignant sinonasal tumours.

A large retrospective study from two belgian institutions of 78 patients who underwent minimally invasive endoscopic management for malignant sinonasal tumors from, 1992-1999 is presented. We attempt to assess the results of this less invasive approach. The spectrum of disease included adenocarcinoma, squamous cell carcinoma, olfactory neuroblastoma and other malignant tumors. All patients were treated primarily for cure. 66 patients were operated on by a purely endoscopic technique, while 9 patients had a simultaneous neurosurgical and endoscopic approach, and 3 a limited orbital approach. 16 patients (20.5%) presented with local recurrence, 6 patients (7.7%) sustained distant metastases and 7 patients (9%) presented simultaneous local recurrence and distant metastases. The 2-years and 5-years survival rates of the whole group were respectively 73.1% and 52.3%, while the adenocarcinoma group exhibits a significantly better prognosis than other histological types with 2-years and 5-years survival rates of 89.8% and 63.8%. Patients who could be treated purely endoscopically had a significantly better survival in comparison to patients treated by an external and endoscopic approach. Morbidity was minimal and the local control rate as well as survival rates were comparable to literature data. Endoscopic resection was adequate, providing clear margins and en bloc removal in most cases. Our results encourage us to use this minimally invasive approach in selected cases as a reliable alternative to the systematic use of an exclusively external approach.

Intraoperative localisation of the primary motor cortex using single electrical stimuli.

A new method of intraoperative localisation of the primary motor cortex is described, based on the application of single anodal electric pulses to the brain surface. Patients were anaesthetised with propofol infusion, and neuromuscular blockade was temporarily alleviated to allow recording of surface EMG responses (CMAPs) to the stimuli. Primary motor areas could be localised in 18/19 patients studied. In the other patient, no responses were elicited, as the operative field was posterior to the motor cortex. When compared with MEPs elicited in awake patients by magnetic stimuli, responses to intraoperative anodal stimulation were of small amplitude (usually less than 10% of MEPs) and their latency was some 1 to 2 ms longer. One month after the operation, only 1/19 patients was left with a slight muscle weakness, although seven showed preoperative motor deficit. The procedure proved easy and fast, needing no preliminary surgery or time consuming preparation. It did not induce any detectable side effects.

Reversal of neurological deficit with naloxone: an additional report.

We report the repeated improvement in neurological function following naloxone administration in a patient who developed acute hemiplegia after an intracranial neurological procedure. The mechanisms responsible for the neurological deficit and for its reversal by naloxone are discussed. A review of the literature suggests that the beneficial effect of naloxone can result from an improvement in haemodynamic status or from metabolic effects that could be favorable during cerebral ischaemia.

Magnetic stimulation of the motor cortex in cervical spondylosis.

We report a new technique of transcranial magnetic stimulation of the motor cortex to measure conduction within central motor pathways of 67 patients with cervical spondylosis or disk herniation. There were upper motor neuron signs in 34 patients (51%) and x-ray evidence of cervical cord compression in 44 (66%). Muscle action potentials (MAPs) to cortical stimulation were abnormal in 84% of patients with, and 22% of those without, radiologic signs of cervical cord compression. Median nerve somatosensory evoked potentials were altered in only 25% of patients. The frequency of MAP alterations correlated with upper motor neuron signs. In 5 (11%) of the 44 patients with x-ray evidence of cervical cord compression, subclinical cord compression was disclosed by cortical stimulation. In 10 patients restudied 3 months after surgical decompression, normalization of central motor conduction time did not occur, indicating permanent damage to the cervical cord.

[Chemonucleolysis. A therapeutic alternative in extra-canalicular lumbar disk hernias]. / La chemonucleolyse. Une alternative thérapeutique des hernies discales lombaires extra-canalaires.

Between 1% and 13% of lumbar disk hernias lie in a very lateral position outside the canal. Diagnosis of the disease is based mainly on CT scan with x-ray. Once conservative therapy has failed, surgery has hitherto been the only treatment proposed, but this generally requires sacrifice of an articular mass. The authors report their experience with chemonucleolysis with chymopapain in five patients presenting this type of hernia. Cure was obtained in four cases. The main advantage of the technique is that osteo-articular structures are preserved.

[Initial clinical signs and results of surgical removal of cerebral arteriovenous malformations]. / Premiers signes cliniques et résultats de l'exérèse chirurgicale des malformations artérioveineuses cérébrales.

On the basis of 90 cerebral AVMs, the authors study clinical signs which show the AVM, before a dramatic bleeding. Such clinical signs are: benign subarachnoid hemorrhage or intracranial hypertension and, only for lobar AVMs, migraine, epileptic seizures, progressive neurological deficit. In such cases a misdiagnosis is avoided by CT Scan with contrast. In the second part, the authors show that the AVMs surgical removal gives better results than AVMs natural history studied over a 20 years period. Ten AVMs observed in deep coma died. Two surgical deaths are only observed out of 73 AVMs surgical removals. Out of 44 lobar AVMs totally removed, 37 show good results and seven disabilities. Out of 19 deep AVMs, 13 were totally removed and six partially. Such deep AVMs, especially AVMs of the corpus callosum or of lateral and third ventricles choroid plexus give excellent surgical results. The authors conclude that surgical removal is the safer treatment for the majority of AVMs (Acta neurol. belg., 1985, 85, 65-81).