Chronologic analysis of symptomatic change following microvascular decompression for hemifacial spasm: value for predicting midterm outcome

Penetrating Offenders in Hemifacial Spasm: Surgical Tactics and Prognosis

(1) Background: In cases of hemifacial spasm (HFS), there are various patterns related to the vascular compression of the facial nerve, including a very rare form that is seen when the offending vessel penetrates the facial nerve. However, there have been few reports in the literature regarding the associated surgical techniques and postoperative prognosis. (2) Methods: A retrospective review was conducted of 4755 patients who underwent microvascular decompression (MVD) surgery from April 1997 to June 2023. In total, 8 out of the 4755 patients (0.2%) exhibited a penetrating offending vessel; the medical and surgical records of these 8 patients were then analyzed. Surgery was then attempted to maximally decompress the penetrating offender. (3) Results: Seven out of the eight patients (87.5%) were spasm-free immediately after surgery, and one had only 10% residual spasm compared to their preoperative condition. That patient was also spasm-free one year later. Postoperative facial palsy occurred in one patient (12.5%) who was assessed as grade II in the House-Brackmann grading system. In another patient, the resection of a small facial nerve bundle did not result in facial palsy. There were no cases of hearing loss or other complications. (4) Conclusions: Decompressing the penetrating offender did not increase the incidence of facial palsy, and the prognosis for hemifacial spasms was good. Therefore, when a penetrating pattern was encountered during MVD surgery, decompression between the penetrating offender and the facial nerve may offer good results.

Operative Findings of over 5000 Microvascular Decompression Surgeries for Hemifacial Spasm: Our Perspective and Current Updates

Hemifacial spasm (HFS) is a hyperactive cranial neuropathy, and it has been well established that the cause of primary HFS is compression on the root exit zone (REZ) of the facial-vestibulocochlear nerve complex (CN VII-VIII) by a vessel or vessels. MVD is the only curative treatment option for HFS with a high success rate and low incidence of recurrence and complications. We categorize six classical compressive patterns on the REZ as well as five challenging types. Knowledge of these patterns may help in achieving a better surgical outcome.

A multivariable prediction model for recovery patterns and time course of symptoms improvement in hemifacial spasm following microvascular decompression

BACKGROUND

Microvascular decompression (MVD) success rates exceed 90% in hemifacial spasm (HFS). However, postoperative recovery patterns and durations are variable.

OBJECTIVE

We aim to study factors that might influence the postoperative patterns and duration needed until final recovery.

METHOD

Only patients following de-novo MVD with a minimum follow-up of 6 months were included. Overall trend of recovery was modeled. Patients were grouped according to recognizable clinical recovery patterns. Uni- and multivariable analyses were used to identify the factors affecting allocation to the identified patterns and time needed to final recovery.

RESULTS

A total of 323 (92.6%) patients had > 90% symptom improvement, and 269 (77.1%) patients had complete resolution at the last follow-up. The overall trend of recovery showed steep remission within the first 6 months, followed by relapse peaking around 8 months with a second remission ~ 16 months. Five main recovery patterns were identified. Pattern analysis showed that evident proximal indentation of the facial nerve at root exit zone (REZ), males and facial palsy are associated with earlier recovery at multivariable and univariable levels. anterior inferior cerebellar artery (AICA), AICA/vertebral artery compressions and shorter disease durations are related to immediate resolution of the symptoms only on the univariable level. Time analysis showed that proximal indentation (vs. distal indentation), males and facial palsy witnessed significantly earlier recoveries.

CONCLUSION

Our main finding is that in contrast to peripheral indentation, proximal indentation of the facial nerve at REZ is associated with earlier recovery. Postoperative facial palsy and AICA compressions are associated with earlier recoveries. We recommend a minimum of 1 year before evaluating the final outcome of MVD for HFS.

Association Study of Apolipoprotein E Gene Polymorphism With Incidence and Delayed Resolution of Hemifacial Spasm

Objective: This study investigates the correlation between Apolipoprotein E gene (APOE) polymorphism and the incidence and delayed resolution of hemifacial spasms.

Methods: The APOE genotypes of 151 patients with hemifacial spasm and 73 control cases were determined by cleaved amplification polymorphism sequence-tagged sites. The distribution of three APOE alleles (ε2, ε3, and ε4) in two groups and the delayed resolution rate in 6 genotypes were calculated and statistically analyzed.

Results: The proportion of patients with APOE ε3/ε4 genotype in the hemifacial spasm group (25.17%) was significantly higher than that in the control group (12.33%) (P = 0.027). In terms of allele frequency, the proportion of the APOE ε4 allele in the hemifacial spasm group (15.56%) was significantly higher than that in the control group (6.85%) (P = 0.009). Meanwhile, the proportion of APOE ε4 allele carriers in the hemifacial spasm group (29.80%) was significantly higher than that in the control group (13.7%) (P = 0.009). Logistic regression analysis showed that the ε4 allele significantly increased the incidence of hemifacial spasm (OR 2.675, 95%CI 1.260-5.678, P = 0.010). Among the 32 patients with a delayed resolution, the ε3/ε3 and ε3/ε4 had the highest proportion in 6 genotypes. The delayed resolution rate of APOE ε3/ε4 (34.21%) was significantly higher than APOE ε3/ε3 (17.78%) (P < 0.05). The delayed resolution rate of APOE ε4 carriers was the highest (33.33%) in the 3 allele carriers, but there was no significant difference among the 3 allele carriers (P = 0.065).

Conclusion: The polymorphism of APOE is relevant to the incidence rate of hemifacial spasms. APOE ε4 allele increases the incidence of hemifacial spasm. The APOE ε4 allele may promote the occurrence of delayed resolution.

How to Improve the Effect of Microvascular Decompression for Hemifacial Spasm: A Retrospective Study of 32 Cases with Unsuccessful First Time MVD

BACKGROUND

 Microvascular decompression (MVD) has become accepted as an effective therapeutic option for hemifacial spasm (HFS); however, the curative rate of MVD for HFS varies widely (50-98%) in different medical centers. This study could contribute to the improvement of the MVD procedure.

METHODS

 We retrospectively analyzed 32 patients in whom initial MVD failed in other hospitals and who underwent a second MVD at our center. The clinical characteristics, operative findings, outcome of the second MVD, and complications were recorded.

RESULTS

 There were 18 women and 14 men (56.3 and 43.7%, respectively). The left-to-right ratio was 19:13. The mean age of the patients was 59.8 years. We found an undiscovered conflict site located in zone 4 in 10 patients and in the root entry zone in 8 patients. The initial MVD failed in nine patients because of ignorance of the arterioles that originate from the anterior inferior cerebellar artery. There were no special findings in four patients. No Teflon felts were found in the whole surgical field in one patient.

CONCLUSION

 Omission of the offending vessel is the most common cause of an unsuccessful MVD. Intraoperative abnormal muscle response associated with the Z-L response is a good measure to correctly identify the involved arterioles.

Facial motor evoked potential with paired transcranial magnetic stimulation: prognostic value following microvascular decompression for hemifacial spasm

OBJECTIVE

Microvascular decompression (MVD) is widely considered the treatment of choice for hemifacial spasm (HFS), but not all patients immediately benefit from it. Numerous electrophysiological tests have been employed to monitor the integrity of the facial nerve prior to, during, and after MVD treatment. The authors sought to verify if facial motor evoked potential (FMEP) with paired transcranial magnetic stimulation (pTMS) can be utilized as a tool to predict prognosis following MVD for HFS.

METHODS

FMEP using pTMS was performed preoperatively and postoperatively for 527 HFS patients who underwent an MVD treatment. Various interstimuli intervals (ISIs), which included 2, 10, 20, 25, 30, 75, and 100 msec, were applied for each paired stimulation and pTMS(%) was obtained. A graph of pTMS(%) versus each ISI was drawn for every patient and its pattern was analyzed in accordance with patients' clinical outcomes.

RESULTS

With ISIs of 75 and 100 msec, pTMS(%) was physiologically further inhibited, whereas it was relatively facilitated under ISIs of 20, 25, and 30 msec; loss of this specific pattern, that is, further inhibition-relative facilitation, indicated impaired integrity of the facial nerve. Those patients who immediately benefited from an MVD and experienced no relapse tended to show proper restoration of this further inhibition-relative facilitation pattern (p = 0.01). Greater resemblance between the physiological pattern of pTMS(%) and postoperative pTMS(%) was correlated to better outcome (p = 0.019).

CONCLUSIONS

A simple linear graph of pTMS(%) versus each ISI may be a helpful tool to predict prognosis for HFS following an MVD.

Different Roles of Microvascular Decompression in Hemifacial Spasm and Trigeminal Neuralgia

Objectives  Microvascular decompression (MVD) involves the same procedure for both hemifacial spasm (HFS) and trigeminal neuralgia (TN), the resulting clinical courses are different. The aim of this study was to compare differences in MVD operations for HFS and TN and to determine the consequences of these differences on the clinical courses of the two diseases. Methods  The medical records of patients who underwent an MVD operation between January 1998 and March 2013 were reviewed. Results  A total of 2,263 patients were enrolled, 222 had TN and 2,040 had HFS. In the HFS group, the estimated cure rates at postoperative years 1, 2, and 3 were 92.0, 93.4, and 93.6%. In the TN group, the estimated cure rates at postoperative years 1, 2, and 3 were 88.4, 89.4, and 91.4%. Comparison of the initial treatment response between the HFS and TN groups did not reveal any statistically significant difference ( p  = 0.338). Among the 1,749 HFS patients initially cured by MVD, 57 were worsened. Among the 181 TN patients treated by MVD, 43 were worsened, with ≥ BNI III (Barrow Neurological Institute pain intensity score III) 12 worsened to a BNI score of IV. Comparing the recurrence rate between the HFS and TN groups, there was a statistically significant difference for cases with ≥ BNI III ( p  < 0.001), but not in cases with ≥ BNI IV ( p  = 0.498). Conclusion  MVD is a promising treatment for HFS. In contrast, MVD-treated TN had a risk of recurrence. The MVD operation should be carefully considered when applied as a treatment for TN patients.

The Potential Value of the Disappearance of the Lateral Spread Response During Microvascular Decompression for Predicting the Clinical Outcome of Hemifacial Spasms: A Prospective Study

BACKGROUND

Hemifacial spasm (HFS) is a benign, chronic, involuntary movement of the muscles involved in facial expressions that typically begins in the orbicularis oculi and spreads to the other expression muscles over several years.

OBJECTIVE

To clarify the effectiveness of intraoperative electromyogram during microvascular decompression (MVD) for HFS.

METHODS

Two hundred ninety-nine consecutive patients with HFS underwent continuous intraoperative monitoring during MVD. The patients were divided into 2 groups based on whether the lateral spread response (LSR) disappeared before or after decompression RESULTS:: In 276 of 299 patients (92.3%), the LSR was observed during intraoperative facial electromyogram monitoring. The mean follow-up period was 17.9 months (range, 12-27 months). Three patients in whom the LSR persisted despite decompression were not included in this study. In 183 of the 273 patients (67%), the LSR disappeared after decompression (group A); in the remaining 90 (33%), the LSR disappeared at dural opening or after drainage of the cerebrospinal fluid before decompression (group B). At the postoperative 3-month and 2-year follow-up visits, there were significant differences in the clinical outcomes between the 2 groups (P < .05).

CONCLUSION

The disappearance of the LSR before and after MVD may predict clinical outcomes. This must be considered together with the disappearance or persistence of LSR after decompression as a prognostic factor for HFS after MVD.

The value of lateral spread response monitoring in predicting the clinical outcome after microvascular decompression in hemifacial spasm: a prospective study on 100 patients

Microvascular decompression represents an effective treatment for hemifacial spasm. The use of lateral spread response (LSR) monitoring remains a useful intraoperative tool to ensure adequate decompression of the facial nerve. The aim of this study was to assess the value of LSRs intraoperative monitoring as a prognostic indicator for the outcome of microvascular decompression in hemifacial spasm. Our study included 100 patients prospectively. The patients were classified into four groups whether LSRs were totally, partially, not relieved, or not detected from the start. According to clinical outcome, the patients were classified into four groups depending on the clinical course after surgery and the residual symptoms if any. Then, correlations were made between LSR events and treatment outcome to detect its reliability as a prognostic indicator. LSRs were relieved totally in 56 % of the patients, partially relieved in 14 %, not relieved in 10 %, and were not detected in 20 % of the patients from the start. HFS was relieved directly after operation in 62 % with clinical improvement of 90-100 %. Thirty-one percent described 50-90 % improvement over the next 3 months after surgery. Almost all of these 31 % (28 out of 31 patients) reported further clinical improvement of 90-100 % within 1 year after surgery. Three percent suffered from a relapse after a HFS-free period, and 4 % reported minimal or no improvement describing 0-50 % of the preoperative state. The percentage of the satisfied patients with the clinical outcome who reported after 1 year a clinical improvement of 90-100 % was 90 %. Statistical analysis did not find a significant correlation between the relief of LSRs and clinical outcome. LSRs may only represent an intraoperative tool to guide for an adequate decompression but failed to represent a reliable prognostic indicator for treatment outcome.

Using the new clinical grading scale for quantification of the severity of hemifacial spasm: correlations with a quality of life scale

BACKGROUND

To date, no consensus has been reached regarding validated and practical tools to quantify the severity of hemifacial spasm (HFS) before and after surgery.

OBJECTIVE

The aim of this study has been to establish objective parameters for determining the preoperative severity of HFS and to assess the correlation with quality of life (QoL) in HFS patients.

METHODS

Patients who experienced HFS between April and August 2010 were reviewed. The patients were divided into four groups according to the severity of spasm (SMC grade): grade I - localized spasm around the periocular area; grade II - involuntary movement spreads to other parts of the ipsilateral face and it affects other muscle groups, i.e. the orbicularis oris, zygomaticus, frontalis or platysma muscle; grade III - interference with vision because of frequent tonic spasms, and grade IV - disfiguring asymmetry. We interviewed each patient using an HFS-7 questionnaire containing a short self-rating QoL scale. We estimated the measure of agreement across observers and examined the relationships between SMC grade and other factors, including HFS-7 responses.

RESULTS

Preoperative evaluation using the SMC grading system showed 25 patients with grade I, 48 patients with grade II, 33 patients with grade III, and 12 patients with grade IV HFS. The HFS-7 scores indicating QoL were 9 (range: 0-17) in grade I, 12 (range: 1-25) in grade II, 16 (range: 2-23) in grade III, and 17 (range: 3-24) in grade IV subjects. SMC grade was correlated with symptom duration (p < 0.0001) and HFS-7 score (p = 0.02). In addition, higher SMC grade was closely associated with longer duration of persisting symptoms (p < 0.05).

CONCLUSIONS

An SMC grading system is useful as a means of quantifying spasms to allow for more precise descriptions of a patient's condition including QoL, and to improve the accuracy of communication between medical teams.

Is entire nerve root decompression necessary for hemifacial spasm?

OBJECTIVE

The root exit zone (REZ) of the seventh cranial nerve has been the target of microvascular decompression surgery (MVD) while searching the neurovascular conflict for treatment of hemifacial spasm for long time. Recently, increasing cases regarding the offending vessel beyond the REZ have been reported. To verify whether a thorough dissection of the nerve may give rise to a better postoperative result without enhancing complications, we conducted a parallel investigation.

PATIENTS AND METHODS

112 Connective entire-nerve-exposed MVDs were performed and compared to 186 REZ-exposed MVDs performed by the same group of surgeons in 2009. The surgical findings, postoperative outcomes and complications as well as microscopic operating time were examined.

RESULTS

Immediately after the surgery, the outcomes were excellent in 98.2%, good in 1.8% and poor in 0% in the entire-nerve-exposed group, compared to excellent in 92.5%, good in 1.6% and poor in 5.9% in the REZ-exposed group. The difference of outcomes between the two groups were statistically significant (χ(2)=4.6845, P=0.0304), but not the complications and microscopic operating time. Nine of the 11 poor-outcome patients from the REZ-exposed group were then reoperated on within a few days, and their symptoms disappeared in eight patients. The main reason for the failed surgeries was that the offending vessels beyond REZ were missed.

CONCLUSIONS

These findings suggested that the entire-root-decompression technique is recommended while performing MVDs in patients with hemifacial spasm.

An analysis of failed microvascular decompression in patients with hemifacial spasm: focused on the early reoperative findings

BACKGROUND

Although the microvascular decompression (MVD) has become a definitive treatment for the primary hemifacial spasm (HFS), there still are some failed cases. To obtain a satisfactory postoperative outcome, those failure cases of MVD need to be analyzed.

METHOD

Between January and October 2009, 393 patients with primary HFS underwent MVD. Postoperatively, 375 presented complete spasm-free, 7 improved apparently, and 11 without any improvement at all. A reoperation was performed in 9 of the 11 patients who had poor outcome within 5 days. Those redo MVD cases were reviewed.

FINDINGS

After the reoperation, the symptom of those patients all disappeared immediately. Therefore, the final outcomes were excellent in 97.7%, good in 1.8%, and poor in 0.5%. Up to the 1 year follow-up period, neither recurrence nor change was found. For the two patients without reoperation, their symptoms remained. The previous surgery was a failure due to insufficient decompression in two and conflict missed in seven.

CONCLUSIONS

A successful MVD operation is attributable to a thorough exploration of the entire nerve course. An early relief should become the ambition of the operator while performing MVD.