Neurovascular conflict and hemifacial spasm.
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Adult↗
Biomedical subjects
M P Sindou
Publications and source records attributed to M P Sindou.
Microvascular decompression for primary hemifacial spasm. Importance of intraoperative neurophysiological monitoring.
There is considerable evidence that primary Hemi-Facial Spasm (HFS) is in almost all cases related to a vascular compression of the facial nerve at its Root Exit Zone (REZ) from brainstem, and that Micro-Vascular Decompression (MVD) constitutes its curative treatment. Clinical as well as electrophysiological features plead for mechanisms of the disease in structural lesions at the neural fibers (putatively: focal demyelination at origin of ephapses) and functional changes in the nuclear cells (hyperactivity of the facial nucleus). Lateral Spread Responses (LSRs) elicited by stimulation of the facial nerve branches testify of these electrophysiological perturbations. Monitoring LSRs during surgery is feasible; however the practical value of their intraoperative disappearance as control-test of an effective decompression remains controversial.MVD allows cure of the disease in most cases. Because the VIIIth nerve is at risk during surgery, intraoperative monitoring of Brainstem Auditory Evoked Potentials (BEAPs) is of value to reduce occurrence of hearing loss. Increase in latency of Peak V and decrease in amplitude of Peak I are warning-signals of an excessive stretching of the the cochlear nerve and impairment of the cochlear vascular supply, respectively.
Cochlear Nerve↗
Stereotactic surgery has merged into general neurosurgery; functional neurosurgery is increasingly 'applied neurophysiology'.
Stereotactic and functional operations represent, altogether, about 20% of all surgeries in a large number of Neurological Institutions, and this percentage is steadily increasing. To a large extent, stereotactic surgery has essentially merged with general neurosurgery. Therefore stereotactic techniques, at least to perform biopsies, should be available to any well-trained neurosurgeon. Functional neurosurgery is increasingly dependent upon clinical neurophysiology, not only for guidance of the procedure, but also for better selection of patients and objective assessment of results. Therefore, the concept of interventional neurophysiology must be recognized and acknowledged.
Humans↗
Neurosurgery for spasticity.
Spasticity is usually a useful substitute for deficiency of motor strength. However not infrequently, it may become harmful leading to an aggravation of motor disability. When excessive spasticity is not sufficiently controlled by physical therapy and pharmacological treatment, patients can have recourse to neurosurgery: neurostimulation, intrathecal baclofen or selective ablative procedures. Because excessive hypertonia has to be reduced without suppression of the useful muscular tone or impairment in the residual motor and sensory functions, neuroablative procedures must be as selective as possible. These selective lesions can be performed at the level of peripheral nerves, spinal roots, spinal cord, or the dorsal root entry zone (DREZ lesions).
Adolescent↗
Neurophysiological navigation in the trigeminal nerve: use of masticatory responses and facial motor responses evoked by electrical stimulationof the trigeminal rootlets for RF-thermorhizotomy guidance.
RF-thermorhizotomy of the trigeminal nerve is an effective and safe treatment of trigeminal neuralgia, provided lesioning of the sensory fibers is performed precisely. To control the accurate placement of the electrode tip, electrical stimulation testing, prior to thermal lesioning, is of prime importance. The clinical observation of direct masticatory responses (DMR) and facial evoked motor responses (EMR) produced by stimulation of the trigeminal rootlets (at 5 Hz) helps to place the electrode tip in the optimal location. The best location is the one where the threshold for eliciting DMR is high and the threshold for evoking facial EMR in the area corresponding to the trigger zone is low. EMR in orbicularis oculi indicates location in V1, levator labii EMR signifies V2 and orbicular oris EMR corresponds to V3.
Aged↗
Most intracranial meningiomas are not cleavable tumors: anatomic-surgical evidence and angiographic predictibility.
OBJECTIVE: The statement that intracranial meningiomas are cleavable tumors has to be seriously questioned from a surgical standpoint. The purpose of this study was 1) to analyze the operative reports of a personal series of meningiomas to evaluate the percentages of the tumors that could be dissected by passing in the extrapial plane (i.e., "cleavable") and of those in which the dissection had to be subpial (i.e., "noncleavable") and 2) to see whether preoperative angiography could help in predicting cleavability. METHODS: The series includes 150 consecutive patients with intracranial meningiomas diagnosed with computed tomographic scans and explored preoperatively by selective external/internal carotid angiography, operated on using microsurgical techniques, and followed for more than 4 years. RESULTS: Dissection between tumor and underlying cortex could be achieved in the extrapial plane predominantly (i.e., on more than two-thirds of the interface) in only 54.6% of patients. On angiography, the pial-cortical arterial supply participated in at least equal part with the meningeal-dural arterial supply in vascularization of the tumor in 59.4% of patients. In this group, dissection could pass through the extrapial plane in only 34.8% of patients. Conversely, when meningeal-dural arterial supply was predominant on angiography, which occurred in 40.6% of patients, dissection could be achieved in the extrapial plane in 83.6% of patients. This difference is statistically significant (P < 0.001). CONCLUSION: Participation of pia mater in the vascular supply of intracranial meningiomas, and consequently, difficulty of dissection, can be predicted preoperatively on angiography. Knowledge of the arterial supply of the tumor before surgery is an important aid to the surgeon in preparing for and performing the operation.
Adolescent↗
Anatomical findings observed during microsurgical approaches of the cerebellopontine angle for vascular decompression in trigeminal neuralgia (350 cases).
The authors report the anatomical pathological findings collected from 1979 to 1992 in a series of 350 consecutive patients referred because of apparently idiopathic trigeminal neuralgia (TN) and operated on using a microsurgical keyhole approach of the cerebellopontine angle. In 20 cases (5.7%) the cause of the TN was a tumor or a vascular malformation, in 8 (2.3%) an atherosclerotic huge vertebrobasilar artery, all actually corresponding to symptomatic TN. Among the 322 others (= real idiopathic TN), only 10 (3.1%) had no visible compressive factor whilst 312 (96.9%) had one (or several) conflicting vessel(s): superior cerebellar artery in 90%, anterior inferior cerebellar artery in 23.6%, and a vein in 24.7%. In 35.7% of the patients, several neurovascular compressions (NVC) were found in association. Site(s) along the root, location around its surface and degree of severity of the conflicts were carefully studied. Of prime importance is the fact that, beside the localized lesions due to the NVC(s), a moderate to marked global atrophy of the entire root was frequently seen (in 67% of the cases) indicating that the NVC might not be the sole pathogenetic agent of the disease.
Adult↗
Removal of the roof of the external auditory meatus in approaching the tentorial notch through a low temporal craniotomy. Technical note.
Improved access to the tentorial notch can be obtained by removal of the roof of the external auditory meatus in association with a low temporal craniotomy. This approach decreases temporal lobe retraction and the risk of venous infarction. This method was perfected in the surgical laboratory on five cadavers and was successfully performed in a patient with a giant aneurysm of the posterior cerebral artery.
Craniotomy↗