Origin of early waves evoked by infraorbital nerve stimulation in man (original) (raw)
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Journal of Neurosurgery, 1996
✓ This paper presents a complete method for performing trigeminal thermorhizotomy, guided by neurophysiological data, to relieve tic douloureux. The method involves the use of trigeminal evoked potentials (TEPs) produced by stimulation of the supraorbital, infraorbital, and mental nerves and recorded from electrodes at both the scalp and the trigeminal nerve. To perform the thermorhizotomy, a cannula is modified to produce a concentric bipolar electrode that is suitable for both recording and lesion making. The operating procedure is divided into five steps: Step 1, recording of baseline scalp TEPs from the derivation of the cervical vertex to C-7 to ensure that all stimulating electrodes are correctly placed; Step 2, recording of TEPs from the trigeminal electrode after stimulation of the peripheral nerve trunks to ascertain the electrode's position relative to the root bundles; Step 3, fine positioning of the trigeminal electrode by recording the root activity evoked by stimul...
Identifying the Trigeminal Nerve Branches for Transovale Radiofrequency Thermolesion
Operative Neurosurgery, 2012
BACKGROUND: Radiofrequency thermorhizotomy of the trigeminal nerve is a known treatment of trigeminal neuralgia. Analysis of verbal responses to electric stimulation of the trigeminal rootlets has been the only method available to localize the affected branch, but patient discomfort may lead to unreliable verbal responses, resulting in increased morbidity or even therapeutic failure. Orthodromically elicited evoked potentials of the trigeminal nerve have also been used, but their application is tedious and results may vary. OBJECTIVE: To develop an electrophysiological method for intraoperative localization of the trigeminal nerve branches. METHODS: A series of 55 patients under general anesthesia during radiofrequency thermorhizotomy were studied. The trigeminal nerve root was stimulated through the foramen ovale with the RF electrode. Antidromic responses were recorded from the 3 divisions of the trigeminal nerve in the face. Effectiveness rate, pain relief, recurrence, complicati...
Generator sites of early scalp potentials evoked from the three trigeminal branches
Journal of Neurosurgery, 1998
Object. The aim of this study was to seek evidence about the generators of the first three components of the scalp's early trigeminal evoked potentials (TEPs) obtained by stimulation of the supraorbital (SW1, SW2, and SW3), infraorbital (W1, W2, and W3) and mental (MW1, MW2, and MW3) nerves. Methods. Simultaneous scalp and depth recordings were measured during surgical procedures in which thermorhizotomy and microvascular decompression were performed. Conclusions. Direct evidence was found that the origin of MW1 lies in the mandibular nerve at the foramen ovale, whereas the origin of W1 in the maxillary nerve at the foramen rotundum and the origin of SW1 in the ophthalmic nerve at the superior orbital fissure could only be inferred. The generators of SW2, W2, and MW2 were found to be on the nerve root at a distance of 10 mm from the pons. Calculations based on conduction velocity suggested that the generators of SW3, W3, and MW3 were inside the brainstem, at distances between 16...
Intracranial stimulation of the trigeminal nerve in man. III. Sensory potentials
Journal of Neurology, Neurosurgery & Psychiatry, 1987
Percutaneous electrical stimulation of the trigeminal root was performed in 18 subjects undergoing surgery for idiopathic trigeminal neuralgia or implantation of electrodes into Meckel's cave for recording of limbic epileptic activity. All subjects had normal trigeminal reflexes and evoked potentials. Sensory action potentials were recorded antidromically from the supraorbital (VI), infraorbital (V2) and mental (V3) nerves. In the awake subject, sensory potentials were usually followed by myogenic artifacts due to direct activation of masticatory muscles or reflex activation of facial muscles. In the anaesthetised and curarised subject, sensory potentials from the three nerves showed 1 4-2-2 ms onset latency, 1-9-2-7 ms peak latency and 17-29 pV amplitude. Sensory conduction velocity was computed at the onset latency (maximum CV) and 'at the peak latency (peak CV). On average, maximum and peak CV were 52 and 39 m/s for VI, 54 and 42 m/s for V2 and 54 and 44 m/s for V3. There was no apparent difference in CV between subjects with trigeminal neuralgia and those with epilepsy. A significant inverse correlation was found between CV and age, the overall maximum CV declining from 59 m/s (16 years) to 49 m/s (73 years). This range of CV is compatible both with histometric data and previous electrophysiological findings on trigeminal nerve conduction. Intraoperative intracranial stimulation is also proposed as a method of monitoring trigeminal function under general anaesthesia.
Pain, 1981
Human trigeminal root evoked potentials have been recorded using signal averaging techniques during radiofrequency trigeminal rhizotomy and lidocaine blocks in patients with trigeminal neuralgia. Both short and long latency trigeminal root potentials have been recorded which appear to represent fast-and slow-conducting fiber activity respectively. Long latency trigeminal root potentials appear in recordings at the noxious threshold as perceived by the awake patient and are relatively selectively abolished in a reversible fashion by lidocaine block and irreversibly by radiofrequency heat. Evaluation of these trigeminai root potentials provides an objective assessment of the results of pain surgery directed at differential destruction of slow-conducting fiber activity.
Sensory and motor trigeminal evoked potentials to localize the position of trigeminal electrodes
Acta Neurochirurgica, 1991
Analysis of verbal responses to electrical stimulation of the trigeminal ganglion and rootlets has been the only method available so far to localize the electrode tip in the most appropriate trigeminal division or division segment, prior to thermocoagulation during percutaneous treatment for trigeminal neuralgia. A diversity of factors may lead to unreliable verbal responses, resulting in increased morbidity or even therapeutic failure. In an attempt to enhance the accuracy of electrode localization during Sweet's procedure, we describe an electrophysiological method complementary to clinical responses. Sensory trigeminal evoked potentials (STEPs) induced by separate successive orthodromic cutaneous stimulation of the three trigeminal divisions and recorded by the isolated tip of a transoval thermocouple electrode, together with motor trigeminal evoked potentials (MTEPs) elicited by stimulation of the trigeminal ganglion and recorded in the ipsilateral temporal muscle, were sequentially examined in six patients undergoing percutaneous tic treatment during gradual rostro-caudal electrode withdrawal. STEPs and MTEPs showed appropriate correlation with verbal and clinical motor responses at each electrode site. General anaesthesia failed to affect STEPs. Systematic exploration in the awake patient of both verbal and clinical motor responses, together with STEPs and MTEPs, is therefore recommended prior to the induction of radiofrequency lesions in the course of percutaneous treatment for trigeminal neuralgia.
Early evoked potentials detected from the scalp of man following infraorbital nerve stimulation
Electroencephalography and Clinical Neurophysiology/Evoked Potentials Section, 1985
Since evidence was found that early, far-field evoked potentials can be averaged from the scalp of humans following auditory and somatosensory stimulation, interest has grown steadily. In fact, recording far-field potentials represents a useful and reliable tool for research and clinical purposes, as conduction of impulses through deep nervous structures can simply be tested using surface electrodes. Research on afferent impulses travelling through the fifth cranial nerve would be of great interest, as this innervates most of the face and can be involved in a number of intracranial pathologies, of known and unknown origin, e.g., trigeminal neuralgia. However, little is known about trigeminal evoked potentials, and even less about their early waves and related far fields. In the cat, far-field potentials originating from the gasserian ganglion and from deep structures along the trigeminal sensory pathway can be recorded from the scalp, as clearly demonstrated by Dong (1982) and by Huang and Feely (1982). Therefore, it may be expected that similar waves could be recorded in man.
A Rare Complication of Trigeminal Nerve Stimulation During Radiofrequency Thermocoagulation
Journal of Neurosurgical Anesthesiology, 2002
Coronary vasospasm resulting from a sudden autonomic response associated with an intracranial procedure was encountered during percutaneous radiofrequency trigeminal rhizotomy. Although it is very rare, careful monitoring and readiness for the occurrence of such a potentially lethal situation with necessary medications may prevent a fatal outcome.
Pain, 1987
Human trigeminal root evoked potentials have been recorded using signal averaging techniques during radiofrequency trigeminal rhizotomy and lidocaine blocks in patients with trigeminal neuralgia. Both short and long latency trigeminal root potentials have been recorded which appear to represent fast-and slow-conducting fiber activity respectively. Long latency trigeminal root potentials appear in recordings at the noxious threshold as perceived by the awake patient and are relatively selectively abolished in a reversible fashion by lidocaine block and irreversibly by radiofrequency heat. Evaluation of these trigeminai root potentials provides an objective assessment of the results of pain surgery directed at differential destruction of slow-conducting fiber activity.