Hearing Preservation After Intervention in Vestibular Schwannoma

Small RNA Deep Sequencing Uncovers microRNAs Associated with Hearing Loss in Vestibular Schwannoma

OBJECTIVE

To analyze the correlation between the miRNA expression profile in vestibular schwannoma (VS) tumor tissue and preoperative patient's hearing status, using the RNA-seq technique.

METHODS

Nineteen tumor samples were collected from patients operated for VS in a Tertiary Academic Center. Samples were classified into "good hearing" and "poor hearing" study group based on the results of audiometric studies. Tumor miRNA expression was analyzed using high-throughput RNA sequencing (RNA-seq) technique, using NovaSeq 6000 Illumina system. Functional analysis was performed with the use of DIANA miRpath v. 4.0 online tool.

RESULTS

The most overexpressed miRNAs in VS samples derived from poor hearing patients belonged to miR 449a/b, miR 15/16-1, and hypoxamiR families. Functional analysis showed that the differentially expressed miRNAs regulate cellular pathways associated with hypoxia, adherence junction functions, and signaling pathways such as Hippo, FOXO, MAPK, and Wnt signaling pathway.

CONCLUSION

Our study identified a specific miRNA expression profile in VS tumor tissues that correlates with hearing impairment. These results suggest potential new molecular mechanisms related to hearing loss in the course of VS.

LEVEL OF EVIDENCE

3 (cohort study) Laryngoscope, 2024.

[Vestibular Schwannoma: Factors in Therapy Decision-Making]

The treatment of vestibular schwannomas (VS) has always posed a challenge for physicians. Three essential treatment principles are available: wait-and-scan, surgery, and stereotactic radiotherapy. In addition to the type of treatment, decisions must be made regarding the optimal timing of therapy, the combination of different treatment modalities, the potential surgical approach, and the type and intensity of radiation. Factors influencing the therapy decision include tumor location and size or stage, patient age, comorbidities, symptoms, postoperative hearing rehabilitation options, patient preferences, and, not least, the experience of the surgeons and the personnel and technical capabilities of the clinical site. This article begins with a brief overview of vestibular schwannomas, then outlines the fundamental interdisciplinary treatment options, and finally discusses the ENT (ear, nose, and throat)-relevant factors in the therapy decision.

CyberKnife Stereotactic Radiosurgery for Growing Vestibular Schwannoma: Longitudinal Tumor Control, Hearing Outcomes, and Predicting Post-Treatment Hearing Status

OBJECTIVES

(1) To determine tumor control rates for treating growing vestibular schwannoma (VS) with CyberKnife stereotactic radiosurgery (CK SRS); (2) to determine hearing outcomes after CK SRS; (3) to propose a set of variables that could be used to predict hearing outcomes for patients receiving CK SRS for VS.

STUDY DESIGN

Retrospective case series review.

METHODS

127 patients who received CK SRS for radiographically documented growing VS were reviewed. Tumors were monitored for post-procedure growth radiographically with linear measurements and three-dimensional segmental volumetric analysis (3D-SVA). Hearing outcomes were reviewed for 109 patients. Cox proportional hazard modeling was used to identify variables correlated with hearing outcomes.

RESULTS

Tumor control rate was 94.5% for treating VS with CK SRS. Hearing outcomes were categorized using the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) classification system. As of their last available audiogram, 33.3% of patients with pre-treatment class A and 26.9% of patients with class B retained their hearing in that class. 15.3% of patients starting with class A or B with extended follow-up (>60 months), maintained hearing within this same grouping. Our final model proposed to predict hearing outcomes included age, fundal cap distance (FCD), tumor volume, and maximum radiation dose to the cochlea; however, FCD was the only statistically significant variable.

CONCLUSION

CK SRS is an effective treatment for control of VS. Hearing preservation by class was achieved in a third of patients. Finally, FCD was found to be protective against hearing loss.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:S1-S12, 2024.

Feasibility Analysis and Surgical Details of Vestibular Schwannoma Resection via Retrolabyrinthine Approach With Preservation of Endolymphatic Sac

Objectives: To study the feasibility of reserving the endolymphatic sac in the cerebellopontine angle (CPA) and the fundus of the internal auditory canal (IAC) by the retrolabyrinthine approach. Design: Single-center retrospective study. Methods: Through 3-dimensional preoperative computed tomography reconstruction, vestibular schwannoma (VS) resection was performed using a retrolabyrinthine approach with preservation of the endolymphatic sac in selected patients, and hearing and facial nerve functions were followed to assess the feasibility of this operation and the effectiveness of function preservation. Results: VS was completely removed in all cases and the postoperative detectable hearing retention rate (AAO-HNS hearing rating grade A, B, and C) was 80% (4/5). Postoperative facial nerve function was well preserved (HB grade I), no leakage of cerebrospinal fluid or other cranial complications was observed in all patients, and no recurrence was observed during follow-up. Conclusions: With less trauma and a promising route for hearing preservation and facial nerve functions, the retrolabyrinthine approach is a potential choice for the treatment of VS located in the IAC-CPA.

Retrosigmoid Approach for Sporadic Vestibular Schwannoma: Patient Selection, Technical Pearls, and Hearing Results

The retrosigmoid corridor provides the most broadly applied approach for resection of sporadic vestibular schwannoma. It may be utilized for any size tumor and for patients with intact hearing with the intention of hearing preservation. For larger tumors, the skull base surgeon must weigh the benefits the retrosigmoid approach against those of the translabyrinthine route. For smaller tumors where hearing preservation is a goal, the retrosigmoid approach is contrasted to the middle fossa route. Hearing preservation is most likely for patients with small and medially located intracanalicular tumors with minimal extension into the cerebellopontine angle, and excellent preoperative hearing.