Teflon Might Be a Factor Accounting for a Failed Microvascular Decompression in Hemifacial Spasm: A Technical Note

Reoperation for residual or recurrent hemifacial spasm after microvascular decompression

PURPOSE

Microvascular decompression (MVD) surgery is the only potential curative method for hemifacial spasm (HFS). Little attention is paid to those recurrent/residual HFS cases. We want to study the potential etiology of those recurrent/residual HFS cases and evaluate the value of reoperation.

METHODS

We retrospectively reviewed reoperation hemifacial spasm patients in our hospital. Intraoperative videos or images were carefully reviewed, and the etiology of recurrent/residual HFS is roughly divided into three categories. Intraoperative findings, surgical outcomes, and complications were carefully studied to assess the value of reoperation for recurrent/residual HFS patients.

RESULTS

A total of 28 cases were included in our case series. Twenty-three of them are recurrent HFS cases, and 5 of them are residual HFS cases. The mean follow-up duration is 24.96 months. There are seventeen patients with missed culprit vessels or insufficient decompression of root exit zone (REZ), eight patients with Teflon adhesion, and three patients with improper application of decompression materials in our case series. The final reoperation outcome with 17 excellent, seven good, and four fair, respectively. Eight (28.57%) of them experienced long-term complications after reoperation.

CONCLUSION

Re-operation for recurrent/residual HFS is an effective therapy and can achieve a higher cure rate. However, the complication rate is higher compared to the first MVD surgery. Accurately identifying REZ and proper decompression strategies to deal with the culprit vessels are very important for surgical success.

TRIAL REGISTRATION NUMBER

UIN: researchregistry7603. Date of registration: Jan. 31st, 2022 "retrospectively registered".

Microvascular decompression for pediatric-onset hemifacial spasm: case series and literature review

OBJECTIVES

Pediatric hemifacial spasm has been rarely reported in the literature, which contains only 44 cases. Although microvascular decompression (MVD) has been widely regarded as effective therapy for hemifacial spasm, the etiology and surgical treatment of pediatric patients are seldom reported. We report our experience with MVD for pediatric hemifacial spasm patients and review the literature with emphasis on the difference from adults.

METHODS

This retrospective report included 4 pediatric HFS patients, who underwent MVD in our department between January 2014 and May 2021 and then reviewed all the pediatric hemifacial spasm literature on "pubmed" with emphasis on the clinical data.

RESULTS

Our series included 1 boy and 3 girls with an average age of 15.6 ± 3.2 years old; their onset ages were from 7 to 16 years old (11.6 ± 4.3). Three patients achieved immediate excellent outcomes and 1 achieved poor immediately and became good 6 months later. During the operation, all the 4 patients were found compressed by anterior inferior cerebellar artery (AICA). The incidence of pediatric atypical hemifacial spasm patients is 12.5% among the 48 reported cases, which is much higher than adults. Among all the reported 48 cases including ours, the singular artery neurovascular conflictions account for 27/48(56%), the singular vein and combined artery/vein conflictions in 12/48(25%) and the cisternal conflictions in 5/48(10.4%) patients.

CONCLUSIONS

The etiology of pediatric hemifacial spasm is still neurovascular conflict, of which combined artery/vein and singular venous compression patterns have a higher proportion, which might explain higher incidence of pediatric atypical hemifacial spasm and less favorable postoperative outcome. Sufficient arachnoid release, full exploration and decompression along the facial nerve are necessary, which would help to increase the excellent postoperative cure rate among pediatric patients.

A Novel Approach to Microvascular Decompression for Hemifacial Spasm: Method Description and Associated Outcomes

BACKGROUND

Microvascular decompression (MVD) is the only potential cure for hemifacial spasm (HFS). However, traditional techniques such as the interposition method may have limited effect in some cases. Alternative techniques have been proposed; however, they can be more complex or difficult to perform than the standard approach.

OBJECTIVE

To describe a safe decompression technique-the "shelter method"-which involves creating a shelter-like space around the facial nerve root exit zone and present associated outcomes.

METHODS

Medical records and intraoperative findings of 92 patients with HFS who underwent MVD using the shelter method between April 1997 and March 2017 were retrospectively reviewed. As a historical control group, we included 53 patients who had undergone MVD by the traditional interposition method before March 1989. The patients were divided into 3 subgroups according to the arteries involved and degree or direction of arterial compression to the seventh nerve. Patient outcomes were assessed as excellent, good, fair, and poor according to the MVD scoring system of the Japan Society for MVD Surgery.

RESULTS

In the shelter method group, complete disappearance of HFS was achieved in 87 patients (94.6%). The curative rate of the shelter method group was significantly higher than that of the interposition method group. The overall complication rates were significantly lower in the shelter method group than in the interposition method group.

CONCLUSION

Our findings indicate high curative and low complication rates of the shelter method, suggesting that it helps treat HFS caused by various types of arterial compression.

Perioperative Nursing Care of Vascular Decompression for Trigeminal Neuralgia under AR Medical Technology

AR technology, also known as AR or virtual reality, refers to a technology that combines and allows interaction of the virtual world on the display system with the real world through the position and angle of the camera video and image analysis technology. This technology is different from VR technology, and its characteristics can be easily explained as follows: when using AR technology, the user's eyes can see not only the real world but also the virtual world derived from the computer through things in the real world. At present, AR has been widely used in education, engineering, entertainment, and medical fields. In order to provide better perioperative care and bring patients a good nursing experience, this article mainly introduces the perioperative care of vascular decompression in the treatment of trigeminal neuralgia by augmented reality medical technology, in order to provide better care for patients with trigeminal neuralgia. This article proposes the perioperative nursing research method of vascular decompression for the treatment of trigeminal neuralgia under AR medical technology, including an overview of trigeminal neuralgia, perioperative related research, and AR medical technology algorithms, and designs related experiments to study whether AR medical technology can bring good news to nursing. Experimental results show that 96% of patients believe that with the enhancement of realistic medical technology, perioperative vascular decompression care for trigeminal neuralgia can help them recover faster and can be gradually popularized.

A New Application of Gelatin Sponge in the Treatment of Hemifacial Spasm by Microvascular Decompression: A Technical Note

OBJECTIVES

 Microvascular decompression (MVD) for facial nerve remains the highly efficient hemifacial spasm (HFS) treatment. Nonetheless, a variety of cases have poor response to MVD. Using Teflon plus gelatin sponge in MVD seems to be a good solution. No existing study has examined the efficacy of using Teflon combined with gelatin sponge during MVD for HFS. Therefore, this study aimed to compare the efficacy of Teflon combined with gelatin sponge in HFS patients relative to that of Teflon alone.

PATIENTS AND METHODS

 We retrospectively compared the follow-up results of patients treated with Teflon and gelatin sponge with those treated with Teflon alone previously. Six hundred and eighty-eight primary HFS patients undergoing surgery from January 2010 to January 2018 were retrospectively analyzed. Three hundred and forty-seven cases received simple Teflon, while 342 cases underwent Teflon combined with gelatin sponge.

RESULTS

 In the Teflon plus gelatin sponge group, the incidences of facial palsy and hearing loss at 1 day, 1 year, and 2 years following surgery was significantly lower than those in the simple Teflon group. Differences in the success rates between Teflon plus gelatin sponge and the simple Teflon group were not statistically significant at 1 day, 1 year, and 2 years after surgery. The recurrence rate in the Teflon plus gelatin sponge group was significantly lower at 2 years.

CONCLUSION

 For HFS patients undergoing MVD, using Teflon plus gelatin sponge can remarkably reduce the incidence of recurrence, facial palsy, and hearing loss compared with those using Teflon alone.

Facial root entry/exit zone contact in microvascular decompression for hemifacial spasm: a historical control study

Background

Microvascular decompression (MVD) surgery is recognized as an effective treatment for hemifacial spasm (HFS). In MVD surgery, biocompatible materials are usually implanted in situ at the neurovascular conflict site in contact with the offending vessel and the facial root entry/exit zone (REZ). Another procedure of implanting the materials between the responsible vessel and the supraolivary fossa without REZ contact has also been applied. However, it is unclear whether there are any differences between these 2 procedures (REZ-contact procedure vs. REZ-non-contact procedure). Therefore, the aim of the present study was to investigate the effect of the placement of implants (contacting or not contacting the facial REZ) on surgical operations and outcomes

Methods

A historical control study was performed. Clinical data of HFS patients who underwent MVD between December 2016 and November 2018 were reviewed and categorized into 1 group with the REZ-contact procedure or another group with the REZ-non-contact procedure according to the decompression strategy they received. Clinical demographics, postoperative outcomes, and complications were collected and compared between the two groups.

Results

Not all patients are suitable for REZ-non-contact decompression. A total of 205 patients were enrolled: 112 in the REZ-contact group and 93 in the REZ-non-contact group. In the early postoperative period, the complete cure rate in the REZ-non-contact group was significantly higher than that in the REZ-contact group. The reappearance and partial relief rates in the REZ-contact group were significantly higher than those in the REZ-non-contact group. The incidence of short-term neurological complications, especially hearing loss and transient facial palsy, was lower in the REZ-non-contact group (P=0.043). But for long-term follow-up of >1 year, there was no significant difference between the two groups in either curative effects or neurological complications. The operating time for REZ-non-contact decompression was relatively longer than for REZ-contact decompression (P=0.000). An unexpected subdural hemorrhage occurred in the REZ-non-contact group.

Conclusions

REZ-non-contact decompression procedure showed superiority only in short-term postoperative outcomes. Given its limitations and potential risks, the REZ-non-contact procedure can be used as an alternative individualized strategy in MVD, and there is no need to pursue REZ-non-contact during the decompression.

Mechanism underlying cranial nerve rhizopathy

The cranial nerve rhizophathy, commonly presented with trigeminal neuralgia (TN) or hemifacial spasm (HFS), is a sort of hyperexcitability disorders with higher incidence in senior Asian. In this paper, a novel hypothesis on the pathogenesis is proposed and with which some clinical phenomena are explained. In those with crowded cerebellopontine angle in anatomy, the cranial nerve root and surrounding vessel are getting closer and closer to each other with aging and finally the neurovascular conflict happens. As the interfacial friction associated with pulse, the nerve incurs demyelination. Since this pathological change develops to a certain degree, some transmembrane proteins emerge from the nerve due to a series of signaling pathway mediated by inflammatory cytokines. Among them, voltage-gated (Na_v1.3) and mechanosensitive (Piezo2) ion channels may play the important role. With pulsatile compressions, the Piezo2 drives the resting potential toward depolarization forming a state of subthreshold membrane potential oscillation. Under this condition, just an appropriate pressure can make the membrane potential easy to reach threshold and activate the sodium channel, eventually generating conductible action potentials from the axon. When these ectopic action potentials propagate to the central nerve system, an illusion of sharp pain is perceived; while to the nerve-muscle junctions, an attack of irregular muscle constriction occurs. This hypothesis can well explain the symptomatic manifestation of paroxysmal attacks aroused by emotions. When we get nervous or excited, our heart rate and blood pressure alter correspondingly, which may give rise to "a just right pressure" - with specific frequency, amplitude and angle - impacting the suffered nerve to reach the threshold of impulse ignition. After a successful microvascular decompression surgery, the trigger is gone (there is no compression anymore) and the symptom is alleviated. While the postoperative recurrence could be attributable to Teflon granuloma development if had been placed improperly - for this nerve root has been susceptible no matter to arteries or to neoplasms. Besides, it may illustrate the clinical phenomenon that secondary TN or HFS cases are seldom caused by schwannoma: with a proliferative sheath, the nerve root is actually insulated. By contrast, not all neurovascular contacts can lead to the onset: it demands an exclusive extent of demyelination firstly.

Clinical analysis of repeat microvascular decompression for recurrent hemifacial spasm

The aim of this study was to investigate the effects of repeat microvascular decompression (MVD) for recurrent hemifacial spasm (HFS). The clinical features, surgical findings, outcomes, and complications of 13 patients who underwent MVD with a history of prior MVD in Xuanwu Hospital between January 2010 and May 2017 were analysed retrospectively. All patients were successfully treated for their HFS but experienced recurrent symptoms and received repeat MVD. Teflon felt factors (9/13, 69.2%) and vascular changes (4/13, 30.8%) were the main reasons for recurrent HFS. With a mean follow-up of 34.6 months after surgery (ranging from 12 to 92 months), 11 (84.6%) patients achieved complete or major spasm alleviation and two patients (15.4%) achieved fair outcomes. Surgical complications included transited mild to moderate facial weakness in two patients (15.4%). None of the patients had serious surgical morbidities. Repeat MVD is an effective and safe treatment for recurrent HFS.

Prosthetic material degeneration over time as a possible factor in delayed recurrence of hemifacial spasm after successful microvascular decompression

Background:

The effectiveness of microvascular decompression in treating hemifacial spasm is widely accepted. However, some experience recurrence of hemifacial spasm after successful decompression surgery. Especially, delayed recurrence more than 5 years after surgery is rare and the cause of this phenomenon is unknown.

Case Description:

A female underwent microvascular decompression to treat her hemifacial spasm 6 years ago. Six years later, her hemifacial spasm recurred and she underwent a second surgery. The second surgery revealed that the sponge had become fragile, losing the ability to absorb the impact of pulsatile compression of the offending artery on the root exit zone of her facial nerve.

Conclusion:

We report a case in which degeneration of material, a sponge (polyurethane), used in decompression surgery caused delayed recurrence of hemifacial spasm. The selection of appropriate prosthetic materials is essential in such functional surgeries.

Revision Microvascular Decompression for Trigeminal Neuralgia and Hemifacial Spasm: Factors Associated with Surgical Failure

Objective  To investigate risk factors for symptom recurrence in patients requiring a revision microvascular decompression (MVD) for trigeminal neuralgia (TN) or hemifacial spasm (HFS). Design  Retrospective review of a prospectively maintained database. Participants  Seventeen consecutive patients undergoing revision MVD at our institution between January 1993 and September 2017. Main Outcome Measures  The incidence and causes for revision MVDs were recorded. Response to revision MVD for TN was tracked using the Barrow Neurological Institute (BNI) grading scale. Response to revision MVD for HFS was graded as "no improvement," "some relief," or "complete resolution" of symptoms. Results  Revision MVD rate for the senior author across all MVDs performed in this period was 1.9% for TN and 9.3% for HFS. Initial MVD failure was primarily caused by active inflammation and/or scarring and adhesions in 5/17 patients, malposition/slippage of Teflon in 3/17 patients, and insufficient Teflon in 1/17 patients. Without other factors, a new site of neurovascular conflict was identified in 4/17 patients, while the same site of neurovascular conflict was found in 3/17 patients. No cause could be identified in 1/17 patients. Scarring was found primarily in the TN group and was associated with symptom persistence. Conclusion  Revision MVD for recurrent TN and HFS is an effective procedure offering the prospect of a complete cure. Proper Teflon use is crucial for surgical success. Scarring after initial MVD is a negative prognostic factor requiring destructive treatment consideration. Although morbidity rates were slightly increased with revision versus original MVDs, the complications were non-disabling and resolved over time.

Flat Posterior Cranial Fossa Affects Outcomes of Microvascular Decompression for Trigeminal Neuralgia

OBJECTIVE

To investigate the prognostic factors for microvascular decompression (MVD) in patients with primary trigeminal neuralgia (TN), with a particular focus on the morphology of the posterior cranial fossa (PCF).

METHODS

The present study investigated 126 surgically treated patients with primary TN with more than 1-year follow-up who underwent high-resolution magnetic resonance imaging between April 2003 and September 2015. We retrospectively reviewed clinical information and operative findings. Outcomes of MVD were also evaluated and patients were classified into "success" and "failure" groups. Furthermore, length, width, and height of the PCF were measured by approximation to an ellipsoid with reference to the anterior commissure-posterior commissure line. These values were compared between groups.

RESULTS

Atypical type 2 TN (P < 0.001) and weak neurovascular compression (P < 0.001) correlated significantly with poor outcomes of MVD for primary TN. In terms of PCF morphology, the failure group showed a flatter PCF than the success group, whereas sex, age, affected side, topography of facial pain, interval between onset and surgery, responsible vessel, location of compression along the nerve, and site of compression around the circumference of the nerve root did not significantly affect outcomes of MVD for primary TN.

CONCLUSIONS

The present study identified type 2 TN, weak neurovascular compression, and flatness of the PCF as predictors of poor prognosis after MVD for primary TN.