1/12. Relationship between cochleovestibular disorders in hemifacial spasm and neurovascular compression.OBJECTIVE: To investigate the evolution of cochleovestibular symptoms before, during, and after microvascular decompression (MVD) of the facial nerve in hemifacial spasm. STUDY DESIGN: Prospective study in patients with hemifacial spasm. Among our 13 patients who underwent MVD of the facial nerve from 1995 to 1997, 6 had associated cochleovestibular disorders confirmed by neurotologic tests. RESULTS: In four of these patients, a concomitant compression of the eighth and facial nerves was found at surgery. Preoperative magnetic resonance angiography studies had shown three cases of this double neurovascular compression. Intraoperative auditory brainstem response monitoring showed that interposition of Teflon between vessel and facial nerve was highly critical to the auditory function. Auditory brainstem response monitoring was used to guide the surgeon during this critical phase. Surgery improved at least one cochleovestibular symptom in each patient. CONCLUSIONS: The authors propose two pathophysiologic hypotheses. First, the concomitant facial and cochleo-vestibular symptoms may be due to a hyperactivity of both the facial and vestibular nuclei. According to theories about cryptogenic hemifacial spasm, the origin of this hyperactivity could be an ectopic excitation focus. However, the two nerves may have different sites of ectopic excitation. According to the second hypothesis, a pulsatile compression of the facial nerve may be transmitted to the eighth nerve. This could take place even if only the facial nerve is in contact with a vascular loop.- - - - - - - - - - ranking = 1keywords = vessel (Clic here for more details about this article) |
2/12. Postoperative oblique sagittal MR imaging of microvascular decompression for hemifacial spasm.Pre-operative and postoperative oblique sagittal gradient-echo magnetic resonance (MR) imaging was used to evaluate micro-vascular decompression of the facial nerves in 26 patients with hemifacial spasm. The pre-operative MR images were divided into two groups as follows: 22 images in Group I, clear imaging of a high-intensity line and/or spot at the root exit zone (REZ) of the facial nerve; and 4 in Group II, and unreliable image around the REZ. Surgery found that the causative vessel was the vertebral artery (VA) in 9 cases and the anterior inferior cerebellar artery (AICA) or the posterior inferior cerebellar artery (pica) in 13 cases in Group I, and the AICA or the pica in the 4 cases in Group II. Postoperative MR imaging showed clear decompression as the high-intensity line and/or spot completely separated from the REZ by a low- and/or iso- intensity area in 9 cases of VA compression repositioned to the petrous dura matter, in 11 cases of pica or AICA compression treated by shredded Teflon pledgets in Group I and in 3 cases in Group II. Postoperative MR imaging showed an incomplete separation of any high-intensity line and/or spot in the REZ in 2 cases of pica or AICA compression in Group I and in one in Group II. The outcome was excellent in 22 of 23 cases with clear decompression, and in 1 of 3 cases of unclear decompression. hemifacial spasm persisted in 3 cases. Oblique sagittal gradient-echo MR imaging is a useful method for postoperative follow-up which can demonstrate changes around the REZ of the facial nerve if hemifacial spasm recurs.- - - - - - - - - - ranking = 1keywords = vessel (Clic here for more details about this article) |
3/12. hemifacial spasm caused by a contralateral vertebral artery: case report.BACKGROUND: hemifacial spasm is usually caused by compression of the facial nerve by ipsilateral blood vessels. Compression of the facial nerve root exit zone by a contralateral tortuous vertebral artery is very rare. methods: This 68-year-old woman presented with left-sided hemifacial spasm and was found to have compression of the left facial nerve by the tortuous vertebrobasilar artery, as revealed by magnetic resonance imaging and magnetic resonance angiography. Retromastoid craniectomy demonstrated compression of the left facial nerve root exit zone by the distal portion of the right vertebral artery. The vertebrobasilar junction and both vertebral arteries were moved laterally from the facial nerve and a muscle implant was interposed between the brainstem and the right vertebral artery. RESULTS: The patient has remained free of hemifacial spasm for a follow-up period of 27 months. CONCLUSIONS: Compression of the facial nerve by the contralateral tortuous vertebral artery may produce hemifacial spasm. A transposed large vessel can be secured by a sling technique or by interposing a soft implant between the brainstem and the vertebral artery.- - - - - - - - - - ranking = 2keywords = vessel (Clic here for more details about this article) |
4/12. Snare technique of vascular transposition for microvascular decompression--technical note.recurrence of trigeminal neuralgia (TN) or hemifacial spasm (HFS) after microvascular decompression (MVD) is not rare. The prosthesis material eventually adheres to the neurovascular structures and again transmits arterial pulsation to the nerve. A snare ligature technique using a Gore-Tex tape can be used for the transposition of the offending artery. No prosthesis is necessary once the transposition is complete. This technique requires introduction of either Gore-Tex tape or thread around the artery and suture over the petrous dura, so an adequate working space as if operating in a shallow basin is essential. Therefore, the osteoplastic craniotomy is a little larger than usual with the scalp flap entirely reflected using a semicircular skin incision. The Gore-Tex tape can be directly snared around the artery and sutured over the petrous dura. If this procedure is difficult, a thread can be attached to both ends of the Gore-Tex tape to pass the tape around the vessel. Seven patients with TN and 13 patients with HFS have undergone this surgery. Although the follow-up period is not yet long enough, there has been no case of recurrence. The present technique for MVD can provide complete and permanent transposition of the offending artery.- - - - - - - - - - ranking = 1keywords = vessel (Clic here for more details about this article) |
5/12. Demonstration of neurovascular compression in trigeminal neuralgia and hemifacial spasm with magnetic resonance imaging: comparison with surgical findings in 60 consecutive cases.BACKGROUND: Until recently, it has been impossible to demonstrate vascular compression at the root entry or exit zone (REZ) of the trigeminal nerve and facial nerve in patients with trigeminal neuralgia (TN) and hemifacial spasm (HFS) preoperatively, although surgical findings have revealed apparent neurovascular compression and its correction has resulted in a good outcome in most cases. Revealing the anatomic correlation between nerves and vessels at the REZ preoperatively would be useful to predict operative findings. methods: To assess whether the vascular contact of the nerve at the REZ could be demonstrated preoperatively, high-resolution magnetic resonance tomographic angiography (MRTA) was performed in 21 patients with TN and 39 with HFS. Neuroradiological findings were compared with the operative findings in all patients. Contralateral asymptomatic nerves were evaluated as a control. RESULTS: MRTA correctly identified offending vessels in 14 (67%) of the 21 TN and 34 (87%) of the 39 HFS patients. Failure to identify neurovascular contact was noted in the cases with compression by veins or small arteries, thickened arachnoid, or distal compression. Neurovascular contact was also observed in 15% of the asymptomatic nerves. The deformity of the nerve seemed to be a more important factor for determining operative indication. CONCLUSIONS: MRTA could demonstrate offending vessels in TN and HFS at a high rate and was useful to predict operative findings. MRTA gave supportive evidence of surgical indications in patients with TN and HFS, although attention should be paid to the fact that MRTA did not necessarily detect all of the offending vessels.- - - - - - - - - - ranking = 4keywords = vessel (Clic here for more details about this article) |
6/12. "Real" three-dimensional constructive interference in steady-state imaging to discern microneurosurgical anatomy. Technical note.Three-dimensional (3D) neuroimages are generally considered useful for neurosurgical practice. Nevertheless, neuroimaging modalities such as 3D digital subtraction angiography and 3D computerized tomography angiography are still insufficient because the resulting images fail to delineate neural structures. Complex neurosurgical procedures are mostly performed in the cerebrospinal fluid (CSF) space of the basal cistern, where vessels and neural structures are present along with the lesion. The magnetic resonance (MR) imaging-derived 3D constructive interference in steady-state (CISS) imaging displays the margin between the CSF and neural structures, vessels, and dura mater in detail, in a two-dimensional fashion. The authors know that volume-rendered 3D CISS images would be more useful for surgery than conventional ones. Although the usefulness of "virtual MR image endoscopy" was reported previously, the endoscopic view is different from the operative field because of the perspective being emphasized. Therefore, to simulate surgical views, the authors made 3D neuroimages from a 3D CISS MR sequence by using an advanced computer workstation. After generating volume images, a cutting method was used in the desired plane to visualize the lesion with reference to a multiplanar reformatted image. The authors call these "real" 3D CISS images, and they are more comparable to the operative field. This newly developed method of producing a real 3D CISS image was used in 30 cases and contributed to the understanding of the relationship between a lesion and surrounding structures before attempting neurosurgical procedures, with minimal invasiveness to the patient.- - - - - - - - - - ranking = 2keywords = vessel (Clic here for more details about this article) |
7/12. hemifacial spasm caused by pontine glioma: case report and review of the literature.hemifacial spasm (HFS) is an involuntary paroxysmal contractions of the facial musculature, caused generally by vascular compression of the seventh cranial nerve at its root exit zone from the brain stem. The case of an adult man harbouring brain stem glioma (BSG) whose only neurological signs were left HFS and mild facial weakness is reported. Radiological and neurophysiological findings are described. No responsible vessel could be identified during surgery, but the causative lesion was found to be an astrocytic tumour encasing the facial nerve at its root exit zone from the brain stem. The rarity of such a condition prompted us to review the literature. Nine cases, including our patient presenting with HFS caused by BSG, are reviewed.- - - - - - - - - - ranking = 1keywords = vessel (Clic here for more details about this article) |
8/12. Endovascular treatment of vertebral artery aneurysm manifesting as progressive hemifacial spasm.A 62-year-old woman presented with right hemifacial spasm persisting for 6 months. Brain magnetic resonance imaging and digital subtraction angiography showed a wide-neck aneurysm of the intracranial portion of the right vertebral artery. The patient underwent endovascular trapping of the aneurysm by coil embolization of the parent vessel on both sides of the aneurysm. The patient experienced gradual disappearance of the hemifacial spasm within 3 months. No relapses occurred during a follow-up period of 3 years. magnetic resonance imaging revealed shrinkage of the vertebral artery aneurysm which had compressed the facial nerve. Endovascular trapping of a vertebral artery aneurysm can be used to treat hemifacial spasm caused by an aneurysm instead of surgical microvascular decompression.- - - - - - - - - - ranking = 1keywords = vessel (Clic here for more details about this article) |
9/12. hemifacial spasm in vertebrobasilar dolichoectasia.Vascular compression of the facial nerve is a well recognized cause of hemifacial spasm (HFS). magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) provide vascular and brain tissue diagnosis in a single non-invasive examination and should be recommended as primary neuroradiological procedure in HFS. We report a rare case of symptomatic HFS caused by a vertebrobasilar dolichoectasia. A 49-year-old women experienced left hemifacial spasm for 10 months. MRI showed an enlarged vertebrobasilar dolichoectasia of the left vertebral artery which compressed the seventh cranial nerve at its exit from the caude pons. MRI is essential in establishing the cause of HFS. Together with MR angiography it shows the correlation among the seventh cranial nerve, blood vessels and the structures of mid-brain. Vertebrobasilar delichoestasia is just one of the blood vessel anomalies which causes HFS and which can be shown by MRI. HFS caused by vertebrobasilar dolichoectasia is quite rare.- - - - - - - - - - ranking = 2keywords = vessel (Clic here for more details about this article) |
10/12. hemifacial spasm caused by vascular compression of the distal portion of the facial nerve. Report of seven cases.It is generally accepted that hemifacial spasm (HFS) and trigeminal neuralgia are caused by compression of the facial nerve (seventh cranial nerve) or the trigeminal nerve (fifth cranial nerve) at the nerve's root exit (or entry) zone (REZ); thus, neurosurgeons generally perform neurovascular decompression at the REZ. Neurosurgeons tend to ignore vascular compression at distal portions of the seventh cranial nerve, even when found incidentally while performing neurovascular decompression at the REZ of that nerve, because compression of distal portions of the seventh cranial nerve has not been regarded as a cause of HFS. Recently the authors treated seven cases of HFS in which compression of the distal portion of the seventh cranial nerve produced symptoms. The anterior inferior cerebellar artery (AICA) was the offending vessel in five of these cases. Great care must be taken not to stretch the internal auditory arteries during manipulation of the AICA because these small arteries are quite vulnerable to surgical manipulation and the patient may experience hearing loss postoperatively. It must be kept in mind that compression of distal portions of the seventh cranial nerve may be responsible for HFS in cases in which neurovascular compression at the REZ is not confirmed intraoperatively and in cases in which neurovascular decompression at the nerve's REZ does not cure HFS. Surgical procedures for decompression of the distal portion of the seventh cranial nerve as well as decompression at the REZ should be performed when a deep vascular groove is noticed at the distal site of compression of the nerve.- - - - - - - - - - ranking = 1keywords = vessel (Clic here for more details about this article) |
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