The effects of dorsal column stimulation on measures of clinical and experimental pain in man.

Despite the extensive use of dorsal column stimulation (DCS) for the control of various chronic pain conditions, most clinicians report only modest success rates. Surprisingly, there has been little placebo-controlled investigation of its efficacy for altering either clinical or experimental pain perception. The current study compared the effects of DCS to placebo stimulation on clinical pain perception, perceived intensity of painful heat stimuli and visual stimuli, and the discrimination of small changes in noxious heat intensity and in light intensity. We found that DCS, but not placebo stimulation, significantly altered ratings of spontaneous clinical pain as well as those of painful cutaneous heat. In addition, heat discrimination thresholds were increased by DCS, but not placebo. On the other hand, DCS had no effect on ratings of visual stimulus intensity nor on visual discrimination, suggesting that the DCS modulation of pain perception was not due to a general change in attention. These data indicate that DCS significantly alters pain transmission in humans. Nevertheless, the relatively small reduction in clinical pain (less than 30%) must be weighed against the invasive nature of electrode implantation.

Facial reinnervation after facial paralysis: is it ever too late?

Following Conley's work on facial nerve cross-over surgery in long-standing facial paralysis, we have reviewed five cases of paralysis of 2.5-7 years' duration. All had complete absence of electrical activity on preoperative EMG and ENG studies. In four of the five cases the facial nerve was not severely atrophic and a "cross-over" technique was feasible. Post-operatively, the results were electrically and clinically good to excellent. To foresee the results of facial nerve cross-over surgery, we have found that the degree of atrophy of the affected nerve at the time of reconstructive surgery is a more important factor than the time lapse since the beginning of the paralysis. Those results also seem better in younger patients. Our findings suggest that hypoglossal-facial cross-overs be considered even 3 years after a paralysis, mostly in younger patients, when the nerve is not severely atrophic. In some cases this technique can be complemented by muscular transfers or selected cosmetic surgery.

Selective peripheral denervation in 111 cases of spasmodic torticollis: rationale and results.

Selective peripheral denervation was performed in 111 patients with total or marked relief of symptoms in 97 (87%). There have been no complications and the only sequelae have been atrophy of the denervated muscles and anesthesia in the territory of the occipital nerves.

Observations and analysis of results in 131 cases of spasmodic torticollis after selective denervation.

In 131 patients treated exclusively by selective denervation during the past 10 years, all or almost all the abnormal movements of spasmodic torticollis were suppressed in 115 (88%) while preserving posture and mobility. This approach was also used in certain forms of adult-onset dystonia. An appreciable amount of abnormal movements remained in the other patients, either due to residual innervation or because of limitation of denervation necessary to preserve normal movements (laterocollis) or neck stability (retrocollis). A medio-lateral approach to the posterior cervical region in the sitting position using stimulation under light anaesthesia is recommended.

Primary hemifacial spasm: a neurophysiological study.

A series of 53 cases of primary hemifacial spasm have been evaluated by means of blink reflexes and their results compared with a normal control group. Reflex responses were obtained by percutaneous electrical stimulus of both the supraorbital nerve (trigemino-facial reflex), and the facial nerve at the stylo-mastoid region (facio-facial reflex). The R2 response was considered abnormal when its latency was shortened (hyperactivity) or delayed (hypoactivity). Thirty-six out of 53 cases with primary hemifacial spasm showed abnormal responses, with a combination of facial nerve impairment (delayed R2 in the facio-facial reflex) and trigeminal-facial hyperactivity (shortened R2 in the trigemino-facial reflex). Five cases showed hyperactivity in both the trigemino-facial reflex and the facio-facial reflex reflexes. These results suggest a state of hyperexcitability, probably at the level of the facial nucleus, combined with a peripheral facial nerve involvement in a high proportion of patients with primary hemifacial spasm.

Bromocriptine in the management of end of dose deterioration in Parkinson's disease.

Thirty-three patients with advanced Parkinson's disease complicated by end of dose deterioration were treated with bromocriptine. The drug was slowly increased so that by treatment week 24 the mean daily dose of bromocriptine was 22mg and levodopa had been decreased by an average of 15 percent. The majority of improvement in daily fluctuations and Parkinsonian disability score was documented by 8 weeks, at which time the mean daily bromocriptine dose was only 12mg. End of dose deterioration was reduced in 78 percent of the patients (mean 43% improvement). Total Parkinsonian disability score was decreased by 33 percent. Adverse effects were minimal; the most common was mild transient early treatment nausea which occurred in 15 percent of the patients. The slow introduction of small doses of bromocriptine, combined with minimal levodopa reduction, can give Parkinsonian patients significant improvement in end of dose deterioration.

The vestibulospinal system and postural regulation in man.

Upright posture in humans represents a giant step phylogenetically speaking. But upright posture demands refined mechanisms for static and dynamic postural equilibrium that are initiated by the concurrence of visual and proprioceptive impulses from the muscles of the legs and the labyrinth. The static labyrinth and Deiter's nucleus via the LVST seem to be the main centers responsible for static equilibrium. Its basic neurophysiological mechanism has been analyzed by the study of stretch reflexes, which permits a semiquantitative evaluation of the function of the static labyrinth. The cerebellum appears as the main control center of the proprioceptive system in relation to dynamic equilibrium.

Bilateral trigeminal neuralgia.

A 56-year-old woman previously treated by a retrogasserian neurectomy for a right tic douloureux was rendered free of pain, but complete anaesthesia of the right half of her face remained. Seven years later, she developed a typical left trigeminal neuralgia. Contralateral rhizotomy was refused because of the patient's concern about having bilateral facial anaesthesia. Through a suboccipital craniectomy, the trigeminal nerve was decompressed from a thickened arachnoid membrane and a large bridging vein near the root entry zone. After eighteen months, the patient was free of pain with intact facial sensations on the left side. Therapeutic considerations in cases of bilateral trigeminal neuralgia are discussed.

Geniculate neuralgia and audio-vestibular disturbances due to compression of the intermediate and eighth nerves by the postero-inferior cerebellar artery.

A compression of the intermediate, cochlear and vestibular parts of the VIII nerve by a redundant loop of the posterior inferior cerebellar artery (PICA) was found at autopsy in a patient who suffered during 21 years of geniculate neuralgia associated with tinnitus, hypoacousia and occasional dizziness. The relationship of arterial cross compression to geniculate neuralgia and audio-vestibular disturbance is discussed.

[Topographic diagnosis of lesions of the acoustico-facial nerve complex using the winking reflex]. / Diagnostic topographique des lésions du complexe acoustico-facial au moyen des réflexes de clignements.

An electrophysiological study in close to 1,500 cases of various lesions of the trigeminal nerve, the acoustico-facial complex and the brain stem was presented. It was concluded that following a detailed clinical examination which, most often, allows precise topographical diagnosis, the study of the trigemino-facial and facial reflexes appears to be an essential diagnostic tool to determine the topography of a lesion. Moreover, this method may give prognostic evaluation as well as facilitate the choice of surgical approach to the lesions of the acoustico-facial complex.

[Electrophysiological evaluation of facial paralysis]. / Evaluation électrophysiologique de la paralysie faciale.

The purpose of this article is to present a new electrophysiological evaluation method to study facial nerve function. This technique studies the afferent sensory pathways and the efferent motor fibres. The study of the various parameters of those two functions allows us to draw certain conclusions relating to the prognosis and localization of facial nerve lesions.

Combined stereotactic and peripheral surgical approach for spasmodic torticollis.

Thalamotomy with or without pallidotomy and peripheral denervation, if necessary, was performed in 14 cases of spasmodic torticollis or other late dystonias. Of 4 bilateral procedures, 2 had a good result, in 1 there was little change and in another the patient remained with a pseudobulbar syndrome, the only complication in this group. 1 patient only required peripheral denervation with a good result. Of the 9 patients who underwent unilateral thalamotomy, with or without pallidotomy, the result was excellent in 6 and good in 2 others, but in 4 of these 8 patients peripheral denervation was also performed.