Fully endoscopic microvascular decompression of the hemifacial spasm: our experience.

PURPOSE: Microvascular decompression (MVD) surgery has been accepted as a potentially curative method for hemifacial spasm (HFS). The primary cause of failure of MVD is incomplete decompression of the offending vessel due to inadequate visualization. This study is aimed at evaluating the benefit of endoscopic visualization and the value of fully endoscopic MVD. METHODS: From March 2016 to March 2018, 45 HFS patients underwent fully endoscopic MVD in our department. From opening the dura to preparing to close, the assistant held the endoscope and the surgeon operated. Abnormal muscle response (AMR) and brainstem auditory evoked potentials (BAEP) were monitored. For every patient, the offending vessel was transposed or interposed and achieved complete decompression. AMR was used to evaluate the adequacy of decompression at the end of the surgery. The intra-operative findings and postoperative outcomes and complications were analyzed. RESULTS: Immediately after surgeries, 39 patients (86.7%) achieved excellent result; 2 cases (4.4%) had good result. So the postoperative effective rate was 91.1% (41/45). During 12-36 month follow-up, the outcomes were excellent in 42 cases (93.3%) and good in 2 cases (4.4%), and the effective rate reached to 97.8% (44/45). No recurrence was noted. The postoperative complications were found in 2 patients (4.4%). One patient (2.2%) showed delayed facial palsy on the tenth day but was fully recovered 1 month later. Intracranial infection was noticed in 1 patient (2.2%) and was cured by using intravenous antibiotics for 2 weeks. There was no hearing impairment, hoarseness, or other complications. CONCLUSIONS: Fully endoscopic MVD is both safe and effective in the treatment of HFS. Electrophysiological monitoring is helpful to gain a good result and reduce hearing impairment.

Posterior Fossa Re-Exploration for Recurrent Trigeminal Neuralgia: Operative Findings and Surgical Techniques.

OBJECTIVE: Microvascular decompression (MVD) is considered the first choice for the surgical treatment of trigeminal neuralgia (TN). However, recurrence after MVD is still a problem and a challenge for neurosurgeons. In this study, we share our experience in the posterior fossa re-exploration of the recurrent cases. METHODS: From January 2014 to January 2015, 15 recurrent TN patients who received fossa re-exploration were retrospectively studied. Surgeries were performed by retrosigmoid suboccipital approach. Brainstem auditory evoked potentials (BAEP) were monitored throughout the operation. Intraoperative findings and surgical techniques were recorded. Postoperative outcomes and complications were analyzed. RESULTS: Among the 15 patients, Teflon adhesion was found in 14. Teflon felt displacement was found in 4 patients, and additional Teflon felt was used to interpose. New offending vessels were found in 5 patients. Three of them were small arteries and the other 2 were petrosal veins. After dissected, small pieces of wet gelatin sponge and Teflon felt were implanted respectively to ensure complete decompression. The remaining 6 patients had no vascular compression except severe adhesion, and nerve combing was performed. After surgery, 12 achieved complete pain relief, 2 gained partial pain relief, and 1 failed. Six patients experienced facial numbness postoperatively. There was no hearing impairment or other complications. During the mean 26-month follow-up, no recurrence occurred and all of 6 cases with facial numbness after surgery improved. CONCLUSIONS: Teflon adhesion is a significant cause of recurrent TN. Wet gelatin-assisted method is good for Teflon interposition. If no vascular compression is found during re-exploration, trigeminal nerve combing can be used. Intraoperative BAEP monitoring is helpful to reduce the incidence of hearing loss.

Microvascular Decompression for Trigeminal Neuralgia: Zone Exploration and Decompression Techniques.

OBJECTIVE: The aim of this study is to introduce zone exploration of the trigeminal nerve and decompression techniques for different types of vasculars. METHODS: The trigeminal nerve was sectioned into 5 zones. Zone 1, 2, 3, 4 was located at the rostral, caudal, ventral, and dorsal part of the nerve root entry zone (REZ) respectively, and zone 5 was located at the distal of the nerve root. This study contained 86 patients with trigeminal neuralgia underwent microvascular decompression. Every zone was exposed through preoperative imaging. During the operation, offending vessels were explored from zone 1 to zone 5, and different decompression techniques were used for different types of vessels. RESULTS: Through zone exploration, the sensitivity of preoperative imaging was 96.5% and specificity was 100%. Location of the neurovascular conflict was in the zone 1 in 53.5% of the patients, zone 2 in 32.6%, zone 3 in 45.3%, zone 4 in 29.1%, and zone 5 in 34.9%. In total, 2 zones were both involved in 59.3%, and 3 zones were involved in 18.6%. All offending arteries were moved away and interposed with Teflon sponge. Offending veins of 11 patients were too small to interpose, and coagulated and cut was adopted. The other offending veins were interposed with wet gelatin and Teflon sponge, respectively. CONCLUSIONS: Zone exploration is helpful in finding offending vessels and adequate decompression can be achieved by choosing different methods according to different types of offending vessels.

Management of vessels passing through the facial nerve in the treatment of hemifacial spasm.

BACKGROUND: In hemifacial spasm, it is extremely rare to find a vessel passing through the facial nerve. In this study, we present our experience of the surgical treatment of four such patients. METHODS: From January 2010 to Match 2015, we treated 2,576 hemifacial spasm patients with microvascular decompression in our department. Of these, four had an intraneural vessel. Intraoperative findings and treatment were recorded, and postoperative outcomes were analyzed. RESULTS: In three patients, the intraneural vessel was the anterior inferior cerebellar artery, which we wrapped with small pieces of wet gelatin and Teflon sponge. A small vein found in the fourth patient was treated with facial nerve combing. Complete decompression was achieved and abnormal muscle response disappeared. Three patients got an excellent result and one patient got a good result. One patient had postoperative facial paralysis, which improved over 10 months of follow-up. CONCLUSION: If an artery passes through the facial nerve, it can be decompressed by wrapping the vessel with wet gelatin and Teflon sponge. If a vein passes through the facial nerve, combing can be used. Intraoperative abnormal muscle response monitoring is very helpful in achieving complete decompression.

Clear cell meningioma: clinical features, CT, and MR imaging findings in 23 patients.

BACKGROUND: Clear cell meningioma (CCM) is a rare meningioma, with radiologic features not well characterized in literature. The purpose of this study was to describe and characterize the clinical features and imaging findings of CCM. MATERIALS AND METHODS: The computed tomography (n = 16) and magnetic resonance (n = 23) images of 23 patients (12 men and 11 women; mean age, 34.6 years) were retrospectively reviewed. All of the patients underwent surgical resection. Follow-up was performed through clinical observations. RESULTS: Cerebellopontine angle was the most frequently presenting location (n = 10). The tumors were isointense (n = 12) or hypointense but associated with isointense (n = 7) appearance to gray matter on T1-weighted images. However, the tumors seemed to be isointense (n = 6) or isointense and hyperintense (n = 13) on T2-weighted images. On gadolinium-enhanced T1-weighted images, heterogeneous enhancement was seen in 14 lesions. Four lesions had amorphous calcifications, 18 showed peritumoral edema, 14 had cystic areas, 2 had bone hyperostosis, and 8 manifested bone destruction. On initial surgery, 17 patients underwent complete resection, whereas 5 patients underwent subtotal resection of their tumors. The operative result for the remaining patient was unknown. Follow-up was possible in 22 patients. Eleven patients had recurrence and 2 had died. CONCLUSIONS: Clear cell meningioma is a rare subtype of meningioma that occurs in younger patients and often recurs. Cerebellopontine angle is the most affected area in this series. The extent of initial surgical resection is the most important prognostic factor. In radiological studies, CCM tends to have marked heterogeneous enhancement, prominent peritumoral edema, intratumoral cystic components, and involvement of the adjacent bone.

Study on surgical approaches and electrode implantation of oculomotor nerve and inferior obliquus in beagle dogs.

OBJECTIVES: To study the surgical anatomy and approaches of intracranial oculomotor nerve (OMN) and inferior obliquus (IO), and the methods of their electrode implantation in dogs. METHODS: The research was performed on 30 adult beagle dogs at Shanghai Jiaotong University Medical College, Shanghai, China from November 2007 to August 2008. All animals were subjected to a right transfrontotemperal approach to intracranial OMN, a transconjunctival route to IO, and the neuro-stimulating and recording electrode implantation under general anaesthesia. The OMN was stimulated and the electromyography of IO recorded and analyzed with the Powerlab System. The security and reliability of the implanted electrodes were investigated. RESULTS: The surgical anatomy and approaches of both the OMN from its exit from midbrain to the entrance into cavernous sinus and the IO were described. Moreover, the implantation methods of OMN stimulating electrode and the electromyographic recording electrode of IO were displayed. The implanted electrodes were safe and reliable. Some electrophysiologic data of IO were obtained in the healthy dogs. Also, some perioperative precautions for intracranial and ophthalmic surgical procedures in dog were exhibited. The mortality rate of the dogs was 0%, and no operative complications were observed. CONCLUSION: With the data provided, these surgical approaches and the methods of electrode implantation offer a choice to construct an animal model for studying various aspects of OMN regeneration.