The Efficacy and Safety of <2 cm Micro-Keyhole Microvascular Decompression for Hemifacial Spasm

Indication for a skull base approach in microvascular decompression for hemifacial spasm

BACKGROUND

A thorough observation of the root exit zone (REZ) and secure transposition of the offending arteries is crucial for a successful microvascular decompression (MVD) for hemifacial spasm (HFS). Decompression procedures are not always feasible in a narrow operative field through a retrosigmoid approach. In such instances, extending the craniectomy laterally is useful in accomplishing the procedure safely. This study aims to introduce the benefits of a skull base approach in MVD for HFS.

METHODS

The skull base approach was performed in twenty-eight patients among 335 consecutive MVDs for HFS. The site of the neurovascular compression (NVC), the size of the flocculus, and the location of the sigmoid sinus are measured factors in the imaging studies. The indication for a skull base approach is evaluated and verified retrospectively in comparison with the conventional retrosigmoid approach. Operative outcomes and long-term results were analyzed retrospectively.

RESULTS

The extended retrosigmoid approach was used for 27 patients and the retrolabyrinthine presigmoid approach was used in one patient. The measurement value including the site of NVC, the size of the flocculus, and the location of the sigmoid sinus represents well the indication of the skull base approach, which is significantly different from the conventional retrosigmoid approach. The skull base approach is useful for patients with medially located NVC, a large flocculus, or repeat MVD cases. The long-term result demonstrated favorable outcomes in patients with the skull base approach applied.

CONCLUSIONS

Preoperative evaluation for lateral expansion of the craniectomy contributes to a safe and secure MVD.

Autologous bone fragments for skull reconstruction after microvascular decompression

Background

Various methods are used to reconstruct the skull after microvascular decompression, giving their own advantages and disadvantages. The objective of this study was to evaluate the efficacy of using autologous bone fragments for skull reconstruction after microvascular decompression.

Methods

The clinical and follow-up data of 145 patients who underwent microvascular decompression and skull reconstruction using autologous bone fragments in our hospital from September 2020 to September 2021 were retrospectively analyzed.

Results

Three patients (2.06%) had delayed wound healing after surgery and were discharged after wound cleaning. No patient developed postoperative cerebrospinal fluid leakage, incisional dehiscence, or intracranial infection. Eighty-five (58.62%) patients underwent follow-up cranial computed tomography at 1 year postoperatively, showed excellent skull reconstruction. And, the longer the follow-up period, the more satisfactory the cranial repair. Two patients underwent re-operation for recurrence of hemifacial spasm, and intraoperative observation revealed that the initial skull defect was filled with new skull bone.

Conclusion

The use of autologous bone fragments for skull reconstruction after microvascular decompression is safe and feasible, with few postoperative wound complications and excellent long-term repair results.

Chronological Patterns of Long-Term Outcomes After Microvascular Decompression for Hemifacial Spasm Over 5 Years

BACKGROUND

The postoperative course of hemifacial spasm (HFS) varies. We analyzed the clinical outcomes from 1 to ≥5 years after microvascular decompression (MVD) in patients with HFS.

METHODS

Between July 2004 and January 2015, 528 patients who were followed up for ≥5 years after MVD for HFS were included. We evaluated chronological patterns of clinical outcomes from 1 to ≥5 years. The outcomes at 2, 3, 4, and ≥5 years postoperatively were individually compared with those at 1 year postoperatively, and the relationships between clinical features, surgical findings, and outcomes over time were analyzed.

RESULTS

Eight groups were created according to the similarity in the pattern of clinical outcomes from 1 to ≥5 years postoperatively. Individual postoperative outcomes at 2-4 years were consistent with those at 1 year postoperatively, whereas postoperative outcomes at ≥5 years were not (P = 0.020). There was substantial to moderate agreement between the outcomes at 1 year and at 2-4 years postoperatively, but the agreement decreased over time. Patients without diabetes (P = 0.015), an intraoperative offending vessel without a vein (P = 0.005), and intraoperative discoloration of the facial nerve (P = 0.036) showed better outcomes at ≥5 years postoperatively.

CONCLUSIONS

Long-term outcomes from 1 to ≥5 years after MVD in patients with HFS were diverse. Nondiabetes, intraoperative offending vessel without a vein, and intraoperative discoloration of the facial nerve were better prognostic factors for outcomes at ≥5 years postoperatively. It is advisable to consider these results when evaluating the long-term outcomes of this surgery.

Association study of the pneumatization degree of mastoid air cells and postoperative complications after microvascular decompression in hemifacial spasm

BACKGROUND

This study aimed to analyse the association between the degree of pneumatization of mastoid air cells (MACs) and postoperative complications after microvascular decompression in hemifacial spasm.

METHODS

We retrospectively reviewed 308 patients with hemifacial spasm who underwent surgery at our institute between January 2017 and March 2021. The degree of pneumatization of MACs was classified into four grades (grades 1, 2, 3, and 4) according to method of Han et al. The clinical data of the four grades were analysed and statistically examined.

RESULTS

There were no statistically significant differences between the four grades in terms of the operative time, intraoperative blood loss, and postoperative hospital stay (all, P > 0.05). The incidence of hearing loss was higher in grade 4 MACs (26.56%) than in grades 1 and 2 MACs (5.41% and 2.89%, respectively; P < 0.05). The incidence of facial paralysis was higher in grade 4 MACs (28.13%) than in grades 1 and 2 MACs (5.41% and 9.18%, respectively; P < 0.001). The incidence of intracranial infection was higher in grade 3 MACs (17.65%) than in grade 2 MACs (3.89%) (P < 0.05). All four patients with cerebrospinal fluid leakage belonged to grade 4 MACs. The incidence of cerebrospinal fluid leakage was higher in grade 4 MACs (5.13%) than in grade 2 MACs (P < 0.05).

CONCLUSIONS

This study found that the degree of pneumatization of MACs was closely related to the postoperative complications after MVD surgeries. Well-pneumatized MACs increase the risk of cerebrospinal fluid leakage and intracranial infection. However, insufficient exposure increases the risk of facial paralysis and hearing loss. For patients with well-pneumatized MACs, sufficient surgical exposure is the top priority when locating the bone hole. For those who may have a latent MAC opening, preventive occlusion should be considered.