Microsurgery of Vestibular Schwannoma Post-radiosurgery

Cystic recurrence of vestibular schwannoma post-radiosurgery: an institutional experience

BACKGROUND

Stereotactic radiosurgery effectively controls vestibular schwannoma (VS). However, in certain cases, microsurgical resection may be necessary for post-radiosurgery tumour progression. The characteristics and microsurgical challenges of uncommon cystic recurrences post-radiosurgery are rarely addressed.

METHOD

We retrospectively analysed 24 consecutive patients who underwent microsurgical intervention for recurrent VS post-radiosurgery by the senior author.

RESULTS

Tumour recurrence post-radiosurgery occurred as solid growth in 19 patients (79%), while 5 patients (21%) developed large brainstem-compressing cysts. The median time interval for tumour recurrence post-radiosurgery was similar between cystic and non-cystic recurrent VS (30 vs. 25 months; p=0.08). Cystic recurrences occurred in primarily cystic VS in 3 patients, and new cysts developed in 2 patients with primarily solid VS. Intra-operatively, tumours were firm in 18 cases (75%) and strongly adhered to surrounding structures in 14 cases (58%). All cystic cases underwent cyst decompression, while complete resection of solid tumour components was avoided due to neurovascular adherence. At a mean follow-up of 42±39 months, 12 patients (50%) showed contrast-enhancing tumour residuals in follow-up imaging, including all cystic recurrent cases. Tumour residuals remained stable without requiring further intervention, except for one patient revealing malignant tumour transformation. House-Brackmann grade I/II was preserved in 15 patients (62%). Three patients (13%) developed new facial palsy, and two patients (8%) improved to House-Brackmann grade II. Cystic recurrences had a significantly higher frequency of tumour residuals compared to solid recurrences (100% vs. 37%; p=0.01) but similar rates of facial palsy (60% vs. 32%; p=0.24) CONCLUSIONS: Cyst development in VS post-radiosurgery is more common in primary cystic lesions but can also occur in rare cases of primary solid VS. Symptomatic cysts require microsurgical decompression. However, complete resection of the solid tumour component is not crucial for long-term tumour control and should be avoided if it risks neurological function in this delicate area.

After the Knife: A Detailed Roadmap for Vestibular Schwannoma Resection in the Semi-Sitting Position - How I do it

BACKGROUND

Vestibular schwannoma surgery remains a neurosurgical challenge, with known risks, dependent on a number of factors, from patient selection to surgical experience of the team. The semi-sitting position has gained popularity as an alternative to the traditional supine position for vestibular schwannoma resection due to potential advantages such as improved surgical exposure due to clearer surgical field and anatomical orientation. However, there is a lack of standardized protocols for performing the procedure in the semi-sitting position, leading to variations in surgical techniques and outcomes.

METHODS

In this study, we aimed to establish a standardized approach for vestibular schwannoma resection using the semi-sitting position. Initiating after final position for semi-sitting, the authors have divided the surgical steps into five major parts for improved understanding and replication. Surgical techniques were analyzed through one hundred steps to identify commonalities, determining the optimal procedural steps for the semi-sitting position using surgical video for visual conceptualization.

RESULTS

The analysis described one hundred steps for vestibular schwannoma resection in the semi-sitting position, with visual demonstration of the various parts of the procedure through surgical videos. Specific recommendations for each step were outlined, including appropriate approach, monitoring strategies, and tumor and posterior fossa structures manipulation. Five major parts of the procedure were identified, leading to a reproducible standardization of the surgical procedure of vestibular schwannoma resection in the semi-sitting position.

CONCLUSIONS

This study provides a comprehensive standardized protocol for the semi-sitting procedure in vestibular schwannoma resection. By establishing a consistent approach, surgeons can minimize variations in surgical techniques and improve patient outcomes. The identified steps and recommendations can serve as a valuable resource for surgical teams involved in vestibular schwannoma resection and facilitate the dissemination and reproducibility of best practices.

Stereotactic radiosurgery for vestibular schwannomas in neurofibromatosis type 2 patients: a systematic review and meta-analysis

INTRODUCTION

Neurofibromatosis type 2 (NF2) is characterized by often bilateral vestibular schwannomas (VS) that result in progressive hearing loss and compression of nearby brainstem structures causing cranial nerve palsies. Treatment of these tumors remains challenging, as both surgical removal and expectant management can result in symptom progression. Stereotactic radiosurgery (SRS) has been investigated for the management of NF2-associated VS; however, the role, promises, and pitfalls of this treatment modality remain unclear.

METHODS

Ovid MEDLINE, EMBASE, Web of Science, and Cochrane Reviews were searched for studies assessing SRS outcome in NF2-associated VS only. Primary endpoints included tumor control, serviceable hearing, presence of tinnitus, and cranial nerve V and VII symptoms.

RESULTS

A total of 16 studies (589 patients harboring 750 tumors) were analyzed. Clinical tumor control was achieved in 88% of cases (95% CI 80-95%); salvage surgery was needed in 8% (95% CI 4-13%) of cases. Treatment resulted in a worsening of pre-treatment serviceable hearing (OR = 0.26, p < 0.01), increased facial nerve (OR = 1.62, p < 0.01) and trigeminal nerve (OR = 1.42, p = 0.07) impairment. The incidence of vestibular symptoms and hydrocephalus were not consistently reported and thus could not be assessed.

CONCLUSIONS

The treatment of NF2-associated VS continues to pose a challenge, as current SRS regimens result in impaired hearing and worse cranial nerve comorbidities, despite achieving high tumor control. It remains unclear if these findings have to be regarded as treatment complications or, rather, continued disease progression.