Dorsal displacement of the facial nerve in acoustic neuroma surgery: clinical features and surgical outcomes of 21 consecutive dorsal pattern cases

Analysis of Related Factors Affecting Facial Nerve Function after Acoustic Neuroma Surgery

Objective

To investigate the factors affecting facial nerve function after acoustic neuroma surgery and to provide theoretical reference for clinicians to preserve facial nerve function better after surgery.

Methods

A retrospective cohort study was conducted to analyze the correlation between postoperative facial nerve function and surgical approach, age, sex, tumor size and adhesion degree of facial nerve in 152 patients with acoustic neuroma.

Results

In the choice of surgical approach, there was no significant difference in the anatomy of the complete facial nerve in labyrinth path, retrosigmoid sinus path, and middle cranial fossa path. There was no statistically significant difference between the middle cranial fossa path and the retrosigmoid sinus path in facial nerve function preservation 7 days after surgery. The difference between middle cranial fossa path and labyrinthine path was statistically significant (P < 0.01). There were statistically significant differences between labyrinth path and retrosigmoid sinus path (P < 0.05). Logistic multivariate regression analysis showed that the operative approach and the degree of adhesion between tumor and facial nerve were the risk factors affecting functional preservation of facial nerve 7 days after surgery. Age and the degree of adhesion between tumor and facial nerve were the risk factors for functional preservation of facial nerve 1 year after operation.

Conclusion

The facial nerve function injury in patients with acoustic neuroma may be related to the choice of surgical approach, the adhesion degree of tumor and facial nerve, and their age. Clinicians need to comprehensively evaluate the risk factors before surgery, so as to achieve individualized treatment to protect the integrity of postoperative facial nerve function of patients.

Facial nerve function and hearing after microsurgical removal of sporadic vestibular schwannomas in a population-based cohort

BACKGROUND

Vestibular schwannoma (VS) is a benign tumor originating from the vestibulocochlear nerve. The optimal treatment strategy is debated, since surgery may result in iatrogenic facial nerve injury. We report the results of VS surgery in a population-based unselected cohort in a center with access to Cyber Knife (CK) radiosurgery.

METHODS

We reviewed 117 consecutive operations and found 95 patients who had their primary operation due to vestibular schwannoma between 2001 and 2017. Facial nerve function was evaluated with the House-Brackmann (HB) scale and hearing with the EU classification.

RESULTS

The population consisted of 37 males and 58 females with a median age of 54 years (range 19-79). One year after surgery 67% of patients had a good outcome (HB 1-2). The rate of good outcome was 90% if no facial nerve damage was observed during intraoperative monitoring, the size of the tumor was under 30 mm and no hydrocephalus was present. During the study period, the treatment strategy changed from total to near-total resection after the introduction of CK radiosurgery, which could be used as a second-line treatment in case of residual tumor regrowth. This resulted in an improvement of outcomes (0% HB 5-6) despite the larger tumor sizes (25 ± 14 mm vs. 31 ± 9 mm, p < 0.05). Hearing preservation rates did not increase.

CONCLUSIONS

Near-total resection and subsequent CK radiosurgery in case of residual tumor regrowth during follow-up seems to provide a good outcome of facial nerve function even in large VSs.

Hearing preservation in vestibular schwannoma surgery via retrosigmoid transmeatal approach

BACKGROUND

Advances in various diagnostic and/or treatment modalities, including radiological imaging, neuromonitoring, and microsurgical techniques, have resulted in treatments of vestibular schwannomas being aimed at preserving facial and hearing functions while achieving optimal tumor control.

METHOD

We describe our surgical technique for hearing preservation in vestibular schwannoma surgery.

CONCLUSION

The retrosigmoid transmeatal approach under continuous neuromonitoring (auditory brainstem response, cochlear nerve action potentials, and continuous facial nerve monitoring) enables gross-total resection of vestibular schwannomas, while preserving hearing and facial functions. Radiological assessment and microsurgical techniques, such as meticulous tumor dissection, are also essential for functional preservation with sufficient tumor removal.

An investigation of life quality of patients after two different acoustic neuroma resections

Background: Patients may suffer postoperative facial nerve injury, hearing loss, or other postoperative complications after the operation, which seriously affect their postoperative life quality. Aims/objectives: To investigate the differences in QOL (quality of life) of patients with acoustic neuroma resection by the translabyrinthine or retrosigmoid approach. Material and methods: Patients with acoustic neuroma resection in our department were enrolled in this experimental study, among which fifty patients underwent the translabyrinthine approach resection, the other 50 patients underwent the retrosigmoid approach resection. Different scores by the SF-36 scale between these two groups of patients one month after discharge were then analyzed. Results: Scores of patients undergoing the retrosigmoid approach were higher in the three dimensions of Social Functioning, Role-emotional and Mental Health than those of patients undergoing the translabyrinthine approach with statistical significance. However, scores of patients undergoing the translabyrinthine approach were higher in the two dimensions of Body Pain and Vitality than those of the patients undergoing the retrosigmoid approach. Conclusions and significance: The results indicated that individual nursing interventions for different patients are necessary to improve the QOL of patients after hospitalization. Moreover, the operated patients with translabyrinthine approach were more advantage than patients with retrosigmoid approach.

The Method for Placement of an Intraoperative Continuous Facial Nerve Stimulating Electrode in Acoustic Neuroma Surgery: Technical Note

Preservation of facial nerve (FN) function is the most important goal in acoustic neuroma (AN) surgery. We have been using intraoperative continuous facial nerve monitoring (ICFNm) of evoked electromyography during AN surgery. ICFNm is very useful, and we can identify the real-time functions of the FN. Some surgeons have experienced difficulty with placing the ICFN stimulating electrode (SE). We therefore show how to place the ICFN SE. We mostly perform AN surgery with a retrosigmoid approach (RSA). A craniotomy with four burr holes is performed. We dissect the arachnoid membrane along the accessory nerve from the cisterna magna to the glossopharyngeal nerve. When we are able to identify the root exit zone (REZ) of the FN near the brainstem, we place the ICFN SE on it. However, when a large tumor covers the REZ, we have to debulk the tumor to create a space between the tumor and the glossopharyngeal nerve. After that, we can place the SE on the REZ. A method for placement of the ICFN SE is needed for some techniques of AN surgery. Once we learn how to place the SE, we can identify continuous FN function during AN surgery. This method is useful for the preservation of postoperative FN function in AN surgery.