ABSTRACT
Trigeminal neuralgia is a disorder characterized by paroxysmal pain arising in one or more trigeminal branches; it is commonly reported in multiple sclerosis. In multiple sclerosis patients the ophthalmic branch may be frequently involved and the risks carried by neurosurgical ablative procedures are higher including major adverse effects such as corneal reflex impairment and keratitis. The objective of this works is to assess the role of posterior hypothalamus neuromodulation in the treatment of trigeminal neuralgia in multiple sclerosis patients. Five multiple sclerosis patients suffering from refractory recurrent trigeminal neuralgia involving all three trigeminal branches underwent deep brain stimulation of the posterior hypothalamus. The rationale of this intervention emerges from our earlier success in treating pain patients suffering from trigeminal autonomic cephalalgias. After follow-up periods that ranged from 1 to 4 years after treatment, the paroxysmal pain arising from the first trigeminal branch was controlled, whereas the recurrence of pain in the second and third trigeminal branches necessitated repeated thermorhizotomies to control in pain in two patients after 2 years of follow-up. In conclusion, deep brain stimulation may be considered as an adjunctive procedure for treating refractory paroxysmal pain within the first trigeminal division so as to avoid the complication of corneal reflex impairment that is known to follow ablative procedures.
Subject(s)
Deep Brain Stimulation , Hypothalamus, Posterior/physiology , Multiple Sclerosis/complications , Multiple Sclerosis/therapy , Trigeminal Neuralgia/complications , Trigeminal Neuralgia/therapy , Aged , Deep Brain Stimulation/adverse effects , Eye Diseases/etiology , Eye Diseases/therapy , Female , Follow-Up Studies , Humans , Magnetic Resonance Imaging , Male , Middle Aged , Pain/etiology , Pain Management , Reflex/physiology , Survival Analysis , Treatment OutcomeABSTRACT
Neuroimaging studies in cluster headache (CH) patients have increased understanding of attack-associated events and provided clues to the pathophysiology of the condition. They have also suggested stimulation of the ipsilateral posterior inferior hypothalamus as a treatment for chronic intractable CH. After 8 years of experience, stimulation has proved successful in controlling the pain attacks in almost 60% of chronic CH patients implanted at various centres. Although hypothalamic implant is not without risks, it has generally been performed safely. Implantation affords an opportunity to perform microrecordings of individual posterior hypothalamic neurons. These studies are at an early stage, but suggest the possibility of identifying precisely the target site by its electrophysiological characteristics. Autonomic studies of patients undergoing posterior hypothalamic stimulation provide further evidence that long-term stimulation is safe, revealing that it can cause altered modulation of the mechanisms of orthostatic adaptation without affecting the baroreflex, cardiorespiratory interactions or efferent sympathetic and vagal functions. Chronically stimulated patients have an increased threshold for cold pain at the site of the first trigeminal branch ipsilateral to the stimulated side; when the stimulator is switched off, changes in sensory and pain thresholds do not occur immediately, suggesting that long-term stimulation is required to induce sensory and nociceptive changes. Posterior inferior hypothalamic stimulation is now established as a treatment for many chronic CH patients. The technique is shedding further light on the pathophysiology of the disease, and is also providing clues to functioning of the hypothalamus itself.
Subject(s)
Cluster Headache/therapy , Deep Brain Stimulation , Hypothalamus, Posterior/physiopathology , Trigeminal Autonomic Cephalalgias/therapy , Adult , Algorithms , Cluster Headache/physiopathology , Dominance, Cerebral/physiology , Electrodes, Implanted , Female , Follow-Up Studies , Humans , Long-Term Care , Magnetic Resonance Imaging , Male , Middle Aged , Neuronavigation , Postoperative Complications/physiopathology , Stereotaxic Techniques , Tomography, X-Ray Computed , Trigeminal Autonomic Cephalalgias/physiopathologyABSTRACT
Microrecordings of three neurons were obtained at the target site in three patients with trigeminal autonomic cephalalgias who were implanted with deep brain stimulators in the posterior hypothalamus. Two patients had chronic cluster headache, one short unilateral neuralgiform headache with conjunctival injection and tearing. Average firing rate was around 24 spikes/s. All neurons were firing randomly, and for most of the recordings in tonic fashion. In one patient, tactile stimulation of the ophthalmic branch, contralateral to the recording site, decreased the firing rate. Neuronal activity in these patients was similar to that reported in animal studies of the posterior hypothalamus. Positioning deep brain stimulators in the posterior hypothalamus may offer a tool to better characterise the activity of this part of the brain in humans.
