Xuesheng Zheng

Clinical features and surgical treatment of trigeminal neuralgia caused solely by venous compression

PurposeTo summarize our experience and lessons of microvascular decompression surgery for trigeminal neuralgia caused solely by venous compression.MethodsFifteen patients with idiopathic trigeminal neuralgia caused by venous compression only underwent microvascular decompression. The entire course of the trigeminal root was explored thoroughly; and coagulating and cutting techniques were preferred in decompressing the culprit veins. Their clinical features, outcomes and operative complications were analyzed.ResultsThe compressing veins included the transverse pontine vein in five cases (33.3%), the transverse pontine vein and the vein of middle cerebellar peduncle in one (6.7%), the transverse pontine vein and the vein of cerebellopontine fissure in one (6.7%), the superior petrosal vein in three (20%), the pontotrigeminal vein in one (6.7%), the vein of the cerebellopontine fissure in two (13.3%), and the plexus venosus or venule in two (13.3%). After microvascular decompression, 11 cases (73.3%) had “excellent” or “good” pain relief. Four cases (26.7%) failed the first surgery; and two of them underwent re-operation and got “excellent” pain relief. Postoperative facial numbness appeared in four cases, due to injury to trigeminal nerve when coagulation.ConclusionThe transverse pontine vein is the most common offending vein. For this type of trigeminal neuralgia, coagulating and cutting techniques are preferred in decompressing the culprit veins. The entire course of the trigeminal root should be explored and decompressed. Following these principles, excellent or good pain relief could be achieved in most cases; and recurrence is rare. However, sometimes injury to the nerve is unavoidable when coagulating the culprit vein.

Re-operation for persistent hemifacial spasm after microvascular decompression with the aid of intraoperative monitoring of abnormal muscle response.

Background and objectivesMicrovascular decompression (MVD) is the only solution that can effectively control hemifacial spasm (HFS). Regarding treatment of the patients who failed the first operation, it is still controversial. We tried to evaluate the safety and efficiency of the early re-exploration for such kinds of patients.MethodsThirteen patients failed the first MVD and received a second MVD procedure. The spasm was not resolved at all or became even more severe after the first MVD. Abnormal muscle response (AMR) persisted during the first MVD operation or disappeared once but emerged again. The patient had a strong will to do the re-operation and was aware of the high risks of operative complications.ResultsAll the 13 patients got good or excellent spasm resolution immediately after the re-operation, which involved whole-range exploration and intraoperative AMR monitoring; however, there were two cases (15.4%) of permanent facial weakness and three cases (23.0%) of transient facial weakness.ConclusionsOur experience on early repeat MVD is whole-range exploration and intraoperative AMR monitoring; in other words, re-operation cannot rely too much on experience.

The role of autonomic nervous system in the pathophysiology of hemifacial spasm.

Abstract Objectives: Despite the vascular compression of the seventh cranial nerve has been verified by the microvascular decompression surgery as the cause of hemifacial spasm (HFS), the mechanism of the disease is still unknown. We believe that the autonomic nervous system in adventitia of the offending artery may contribute to the HFS. To prove our hypothesis, we performed an experiment in SD rats. Methods: Moller’s HFS model was adopted and the abnormal muscle response (AMR) wave was electrophysiologically monitored. With randomization, some HFS rats underwent exclusion of the offending artery or removal of the ipsilateral superior cervical ganglion. Some HFS rats with negative AMR following exclusion of the offending artery were dripped with norepinephrine onto the neurovascular conflict site. Results: With exclusion of the offending artery, AMR disappeared in 14 (70%) of the 20 HFS rats, while in three (30%) of the 10 from sham operation group (P<0·05). With ganglionectomy, AMR disappeared in 12 (75%) of the 16 HFS rats, while in two (25%) of the eight from the sham operation group (P<0·05). With norepinephrine drip, AMR reappeared in four (67%) of the six from those offending-artery-excluded HFS rats, while in zero of the six from normal-saline-dripped group (P<0·05). Discussion: The neurotransmitter releasing from the autonomic nervous endings in the worn adventitia of the offending artery may induce an ectopia action potential in those demyelinated facial nerve fibers expanding to the neuromuscular conjunction and trigger an attack of HFS.

Surgical treatment of hemifacial spasm with zone-4 offending vessel

BackgroundIncreasing evidence shows that vascular compression on any of the four zones of facial nerve may cause hemifacial spasms. Vascular compression on zone 4 (the cisternal portion) of the nerve is quite common, but only a very small percentage of such compression will elicit hemifacial spasm, because zone 4 is less susceptible than zone 3 (the root exit zone). Therefore, it seems difficult for the neurosurgeons to distinguish the real culprit vessels in zone 4. Here, our experience in treating vascular compression located in zone 4 of the facial nerve is reported.MethodsTwelve patients of HFS due to compression of zone 4 were treated with microvascular decompression (MVD) surgery with the aid of combined monitoring of abnormal muscle response (AMR) and Z-L response (ZLR).ResultsAll of the 12 patients had a zone 4 compression. In addition, there were vascular compressions on zone 3 (the root exit zone) and/or zone 2 (the attached segment) in six cases. AMR was absent in two cases, unstable in one case, and persisted after vascular decompression in another one case. ZLR was stable before decompression of zone 4 and disappeared after decompression in all cases. After MVD surgery, 11 patients were cured and one patient achieved good resolution of spasm. One patient had postoperative transient tinnitus.ConclusionsThe neurosurgeon should not ignore vascular compression at zone 4, especially when compressions at zones 2 and 3 co-exist. With the aid of AMR and ZLR, we are able to judge whether offending vessels exist at zone 4.

The strategy of microvascular decompression for hemifacial spasm: how to decide the endpoint of an MVD surgery.

ObjectiveMicrovascular decompression (MVD) has become the standard treatment for hemifacial spasm. As not all patients get complete relief, this strategy is still controversial. The study aimed to figure out how to tell the proper endpoint to the surgery.MethodsA series of 356 consecutive patients with hemifacial spasm were enrolled in this study. All patients fell into two groups according to the period they presented. Two different criteria (simple criterion vs. complex criterion) to end an operation were applied respectively. The intra-operative finding, results and complications of these two groups were compared. The advantage of the complex criterion was analyzed.ResultsThe group which used complex criterion got better results than the group which used simple criterion. The complex criterion which combines full-length evidence, vascular evidence and electrophysiological evidence proved to be reliable to tell the proper endpoint to the surgery.ConclusionMVD operations can be ended only after the full-length evidence, vascular evidence and electrophysiological evidence are all present.

The mechanism of hemifacial spasm: a new understanding of the offending artery

Abstract Although neurovascular confliction was believed to be the cause of hemifacial spasm (HFS), the mechanism of the disorder remains unclear to date. Current theories, merely focusing on the facial nerve, have failed to explain the clinical phenomenon of immediate relief following a successful microvascular decompression surgery (MVD). With the experience of thousands of microvascular decompression surgeries and preliminary investigations, we have learned that the offending artery may play a more important role than the effect of merely mechanical compression in the pathogenesis of the disease. We believe that the attrition of neurovascular interface is the essence of the etiology, and the substance of the disease is emersion of ectopic action potentials from the demyelinated facial nerve fibers, which were triggered by the sympathetic endings from the offending artery wall. In this paper, we put forward evidence to support this hypothesis, both logically and theoretically.

Neuronavigator-guided percutaneous radiofrequency thermocoagulation in the treatment of trigeminal neuralgia.

BackgroundAlthough radiofrequency thermocoagulation is considered as a primary treatment for most patients with trigeminal neuralgia, neuronavigator-guided percutaneous radiofrequency thermocoagulation has been rarely reported. The object of this study was to assess the clinical value of neuronavigator-guided percutaneous radiofrequency thermocoagulation in the treatment of trigeminal neuralgia.MethodsThe radiofrequency thermocoagulation was performed in 100 cases of trigeminal neuralgia. The patients were positioned supine or sitting, under Hartel’s technique (reported by Sweet and Wepsic J Neurosurg 40:143–156, 1974), by anterior lateral facial approaches. The Gasserian ganglions were acupunctured, assisted by intraoperative CT scanning (3-digital reconstruction) and electrophysiology in order to accurately locate target.ResultsThe needles located in oval foramen at the first puncture, the direction and position could be defined according to the electrophysiology examination. The pain alleviated immediately after operation. There occurred no serious complication and other nerve injury in all patients despite face numbness only.Conclusions3D-CT and electrophysiology Gasser’s ganglion locations can raise the success rate of puncture, enhance the safety and reduce the incidence of complication, showing high academic value and its promising future.

Hemifacial spasm caused by cross type vascular compression

Abstract Objectives: The meatal segment of anterior inferior cerebellar artery usually crosses over the gap between cranial nerves VII and VIII, and may compress the cisternal portion (CP) of the facial nerve. This is defined as cross type compression, which is easy to be neglected and thus leads to poor outcome. Here our experience in treating patients of cross type hemifacial spasm (HFS) is reported. Methods: Twenty-one patients of HFS due to cross type compression were treated with microvascular decompression (MVD) surgery with the aid of abnormal muscle response monitoring. Results: In addition to cross type compression at CP, there were typical vascular compressions on the root exit zone and attached segment in 20 cases. After MVD surgery, 17 patients were cured, 3 patients achieved good resolution of spasm, and the other 1 patient got delayed resolution. Three patients had postoperative transient hearing loss and/or tinnitus. Discussion: Even there are apparently typical vascular compressions at proximal portion of the facial nerve, the surgeon should be aware that cross type compression at the CP may co-exist. With the aid of abnormal muscle response (AMR) monitoring, MVD is efficient for patients due to cross type compression.

Evaluation of the Clinical Efficacy of Multiple Lower Extremity Nerve Decompression in Diabetic Peripheral Neuropathy

BACKGROUND In 1992, Dellon reported the first use of peripheral nerve decompression surgery in the treatment of limb diabetic peripheral neuropathy (DPN). However, the efficacy of this procedure is still under debate. In this clinic study, we analyzed the therapeutic effect of microsurgical peripheral nerve decompression for DPN patients, using both clinical evaluation and electrophysiological testing. PATIENTS AND METHODS In 560 patients with DPN , the surgical nerve decompression as described by Dellon was performed. Before and 18 months after surgery, Toronto Clinical Scoring System, quantitative sensory testing, and nerve conduction velocity tests were evaluated in all cases. The control group included 40 diabetic patients in the same age range but without DPN. RESULTS The scores of nerve conduction velocity, quantitative sensory testing, and Toronto Clinical Scoring System improved significantly after microsurgical decompression of the entrapped nerves, although they were still worse than in the control group. According to the Wagner classification, 208 cases (37.1%) were rated as 1 (surface ulcer, no clinical infection) before surgery, but all were rated as 0 (no surface ulcer) 18 months after surgery. CONCLUSION Microsurgical decompression of entrapped peripheral nerves for DPN helped improve nerve conduction, restore lower limb feeling and motor function, and cure ulcers.

The high-resolution ultrasonography and electrophysiological studies in nerve decompression for ulnar nerve entrapment at the elbow.

OBJECTIVE To discuss a combination of high-resolution ultrasound and electrophysiological examination in diagnosis and evaluation of ulnar nerve entrapment at the elbow. METHOD We retrospectively reviewed 20 healthy volunteers and 278 patients of ulnar nerve entrapment divided into three groups by McGowan grade, and we treated patients with subcutaneous or modified submuscular ulnar nerve transposition randomly. All the patients were followed for 2 years. The diagnosis and effects were confirmed by preoperative or postoperative cross-sectional area (CSA), motor conduction velocity (MCV), sensory conduction velocity, and nerve action potential (NAP). RESULTS Healthy volunteers and grade I patients had significant differences in CSA, MCV, and NAP; grade I, II, and III patients had significant differences in CSA, MCV, and NAP; all patients had significant differences in CSA, MCV, and NAP before and after operations. CONCLUSION High-resolution ultrasound and electrophysiological examination can be used in diagnosis and evaluation of operations of ulnar nerve entrapment at the elbow.