Mobilization of the Anterior/Posterior Inferior Cerebellar Artery on the Cerebellar Surface in Microvascular Decompression Surgery for Hemifacial Spasm: Potential Effect on Hearing Preservation

2018 ◽  
Vol 16 (2) ◽  
pp. 179-185 ◽  
Author(s):  
Kenichi Amagasaki ◽  
Saiko Watanabe ◽  
Atushi Hosono ◽  
Hiroshi Nakaguchi

Abstract BACKGROUND The infrafloccular approach in microvascular decompression (MVD) for hemifacial spasm (HFS) reduces the risk of postoperative hearing impairment. However, location of the anterior/posterior inferior cerebellar artery (AICA/PICA) on the cerebellar surface in the surgical route requires mobilization to maintain the approach direction for the protection of hearing function. OBJECTIVE To evaluate the effectiveness of mobilization of the AICA/PICA on the cerebellar surface in the surgical route. METHODS Retrospective review of 101 patients dividing their cases into 2 groups, the mobilized group and nonmobilized group. Surgical results, brainstem auditory evoked potentials (BAEPs), age, and duration of microsurgery were compared. In the mobilized group, whether the artery was responsible for the HFS or not, and whether the artery branched perforators to the cerebellar surface or choroid plexus or not, were analyzed. RESULTS No permanent hearing impairment occurred in any patient. The AICA/PICA was mobilized in 26 patients. No significant difference was found in surgical results, BAEP findings, and duration of microsurgery between the 2 groups, but age was younger in the mobilized group (P < .01). The mobilized artery was responsible in 14 cases and branched perforators in 7 cases in the mobilized group. The perforators did not obstruct mobilization. CONCLUSION Mobilization of the AICA/PICA from the cerebellar surface is a useful technique to maintain the infrafloccular approach in MVD for HFS. This technique reduces the risk of postoperative hearing impairment.

1991 ◽  
Vol 75 (3) ◽  
pp. 388-392 ◽  
Author(s):  
Shinji Nagahiro ◽  
Akira Takada ◽  
Yasuhiko Matsukado ◽  
Yukitaka Ushio

✓ To determine the causative factors of unsuccessful microvascular decompression for hemifacial spasm, the follow-up results in 53 patients were assessed retrospectively. The mean follow-up period was 36 months. There were 32 patients who had compression of the seventh cranial nerve ventrocaudally by an anterior inferior cerebellar artery (AICA) or a posterior inferior cerebellar artery. Of these 32 patients, 30 (94%) had excellent postoperative results. Of 14 patients with more severe compression by the vertebral artery, nine (64%) had excellent results, three (21%) had good results, and two (14%) had poor results; in this group, three patients with excellent results experienced transient spasm recurrence. There were seven patients in whom the meatal branch of the AICA coursed between the seventh and eighth cranial nerves and compressed the dorsal aspect of the seventh nerve; this was usually associated with another artery compressing the ventral aspect of the nerve (“sandwich-type” compression). Of these seven patients, five (71%) had poor results including operative failure in one and recurrence of spasm in four. The authors conclude that the clinical outcome was closely related to the patterns of vascular compression.


2021 ◽  
Author(s):  
Ehab El Refaee ◽  
Steffen Fleck ◽  
Marc Matthes ◽  
Sascha Marx ◽  
Joerg Baldauf ◽  
...  

Abstract BACKGROUND Microvascular decompression (MVD) is the most effective treatment option for hemifacial spasm (HFS). However, deeply located forms of compression would require proper identification to allow for adequate decompression. OBJECTIVE To describe the usefulness of endoscopic visualization in one of the most challenging compression patterns in HFS, where the posterior inferior cerebellar artery (PICA) loop is severely indenting the brain stem at the proximal root exit zone of facial nerve along the pontomedullary sulcus. METHODS Radiological and operative data were checked for all patients in whom severe indentation of the brainstem by PICA at pontomedullary sulcus was recorded and endoscope-assisted MVD was performed. Clinical correlation and outcome were analyzed. RESULTS A total of 58 patients with HFS were identified with radiological and surgical evidence proving brainstem indentation at the VII transitional zone. In 31 patients, PICA was the offending vessel to the facial nerve. In 3 patients, the PICA loop was mobilized under visualization of a 45° endoscope. A total of 31 patients had a mean follow-up duration of 52.1 mo. The mean duration between start of complaints and surgery was 7.2 yr. In the last follow-up, all patients had remarkable spasm improvement. A total of 5 patients had more than 90% disappearance of spasms and 26 patients experienced spasm-free outcome. CONCLUSION Although severe indentation of brain stem implies morphological damage, outcome after MVD is excellent. A 45° endoscope is extremely helpful to identify compression down at the pontomedullary sulcus. Deeply located compression site can easily be missed with microscopic inspection alone.


2016 ◽  
Vol 125 (5) ◽  
pp. 1061-1067 ◽  
Author(s):  
Byung-Euk Joo ◽  
Sang-Ku Park ◽  
Kyung-Rae Cho ◽  
Doo-Sik Kong ◽  
Dae-Won Seo ◽  
...  

OBJECTIVE The aim of this study was to define a new protocol for intraoperative monitoring (IOM) of brainstem auditory evoked potentials (BAEPs) during microvascular decompression (MVD) surgery to treat hemifacial spasm (HFS) and to evaluate the usefulness of this new protocol to prevent hearing impairment. METHODS To define the optimal stimulation rate, estimate the number of trials to be averaged, and identify useful warning criteria in IOM of BAEPs, the authors performed a preliminary study of 13 patients with HFS in 2010. They increased the stimulation rate from 10.1 Hz/sec to 100.1 Hz/sec by 10-Hz increments, and they elevated the average time from 100 times to 1000 times by 100-unit increments at a fixed stimulus rate of 43.9 Hz. After defining the optimal stimulation rate and the number of trials that needed to be averaged for IOM of BAEPs, they also identified the useful warning criteria for this protocol for MVD surgery. From January to December 2013, 254 patients with HFS underwent MVD surgery following the new IOM of BAEPs protocol. Pure-tone audiometry and speech discrimination scoring were performed before surgery and 1 week after surgery. To evaluate the usefulness of the new protocol, the authors compared the incidence of postoperative hearing impairment with the results from the group that underwent MVD surgery prior to the new protocol. RESULTS Through a preliminary study, the authors confirmed that it was possible to obtain a reliable wave when using a stimulation rate of 43.9 Hz/sec and averaging 400 trials. Only a Wave V amplitude loss > 50% was useful as a warning criterion when using the new protocol. A reliable BAEP could be obtained in approximately 9.1 seconds. When the new protocol was used, 2 patients (0.8%) showed no recovery of Wave V amplitude loss > 50%, and only 1 of those 2 patients (0.39%) ultimately had postoperative hearing impairment. When compared with the outcomes in the pre-protocol group, hearing impairment incidence decreased significantly among patients who underwent surgery with the new protocol (0.39% vs 4.02%, p = 0.002). There were no significant differences between the 2 surgery groups regarding other complications, including facial palsy, sixth cranial nerve palsy, and vocal cord palsy. CONCLUSIONS There was a significant decrease in postoperative hearing impairment after MVD for HFS when the new protocol for IOM of BAEPs was used. Real-time IOM of BAEPs, which can obtain a reliable BAEP in less than 10 seconds, is a successful new procedure for preventing hearing impairment during MVD surgery for HFS.


2010 ◽  
Vol 66 (suppl_2) ◽  
pp. ons275-ons280 ◽  
Author(s):  
Masatou Kawashima ◽  
Toshio Matsushima ◽  
Tooru Inoue ◽  
Toshihiro Mineta ◽  
Jun Masuoka ◽  
...  

Abstract OBJECTIVE Our surgical results were reviewed to clarify the cause of glossopharyngeal neuralgia (GPN) and the effects of the microvascular decompression (MVD) procedure. METHODS Fourteen cases of idiopathic GPN were operated on through the transcondylar fossa (supracondylar transjugular tubercle) approach. Their clinical data and operative records were retrospectively reviewed. RESULTS In every case, vascular compression on the glossopharyngeal nerve was found and MVD was performed without any major complications. In 13 of the 14 cases the neuralgia completely disappeared postoperatively. Recurrence of pain was found in 1 case. Offending vessels were the posterior inferior cerebellar artery (PICA) in 10 cases, the anterior inferior cerebellar artery (AICA) in 2 cases, and both arteries in 2 cases. In 10 of the 14 cases, the high-origin PICA formed an upward loop between the glossopharyngeal and vagus nerves, compressing the glossopharyngeal nerve upward. In those cases, the PICA was transposed and fixed to the dura mater by the stitched sling retraction technique, and MVD was very effective. CONCLUSION The offending artery was the PICA in most cases. MVD is expected to be very effective, especially when the radiological images show the following 3 findings: 1) high-origin PICA, 2) the PICA making an upward loop, and 3) the PICA coursing the supraolivary fossette. The transcondylar fossa approach is suitable for transposing the PICA by the stitched sling retraction technique, and provides sufficient surgical results.


2019 ◽  
Vol 80 (04) ◽  
pp. 285-290 ◽  
Author(s):  
Hua Zhao ◽  
Yinda Tang ◽  
Xin Zhang ◽  
Jin Zhu ◽  
Yan Yuan ◽  
...  

Objective To evaluate clinical features, outcomes, and complications in patients with hemifacial spasm (HFS) after microvascular decompression (MVD) of different offending vessels. Methods Clinical data were collected from 362 patients with HFS treated with MVD between January 2013 and January 2014. Patients were divided into five groups based on the offending vessel: A (anterior inferior cerebellar artery [AICA] compression), B (posterior inferior cerebellar artery [PICA] compression), C (AICA plus PICA compression), D (vertebral artery [VA] compression), and E (VA plus small vessel compression). Results The most common offending vessel was the AICA (51.38%). The most common compression site was the root exit zone. During the follow-up period, the effective rate was 95.48% in group A, 92.15% in group B, 93.10% in group C, 90.14% in group D, and 91.45% in group E. Twenty-nine patients exhibited delayed facial palsy, the most common complication. Conclusion No statistically significant differences were found in long-term outcomes or MVD-related complications among the study groups. The type of offending vessel was not a prognostic factor for MVD in patients with HFS.


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