Comparison of surgical outcomes in cystic and solid vestibular schwannomas: a systematic review and meta-analysis

Cystic vestibular schwannoma - a subgroup analysis from a comparative study between radiosurgery and microsurgery

Some vestibular schwannoma (VS) show cystic morphology. It is known that these cystic VS bear different risk profiles compared to solid VS in surgical treatment. Still, there has not been a direct comparative study comparing both SRS and SURGERY effectiveness in cystic VS. This retrospective bi-center cohort study aims to analyze the management of cystic VS compared to solid VS in a dual center study with both microsurgery (SURGERY) and stereotactic radiosurgery (SRS). Cystic morphology was defined as presence of any T2-hyperintense and Gadolinium-contrast-negative cyst of any size in the pre-interventional MRI. A matched subgroup analysis was carried out by determining a subgroup of matched SURGERY-treated solid VS and SRS-treated solid VS. Functional status, and post-interventional tumor volume size was then compared. From 2005 to 2011, N = 901 patients with primary and solitary VS were treated in both study sites. Of these, 6% showed cystic morphology. The incidence of cystic VS increased with tumor size: 1.75% in Koos I, 4.07% in Koos II, 4.84% in Koos III, and the highest incidence with 15.43% in Koos IV. Shunt-Dependency was significantly more often in cystic VS compared to solid VS (p = 0.024) and patients with cystic VS presented with significantly worse Charlson Comorbidity Index (CCI) compared to solid VS (p < 0.001). The rate of GTR was 87% in cystic VS and therefore significantly lower, compared to 96% in solid VS (p = 0.037). The incidence of dynamic volume change (decrease and increase) after SRS was significantly more common in cystic VS compared to the matched solid VS (p = 0.042). The incidence of tumor progression with SRS in cystic VS was 25%. When comparing EOR in the SURGERY-treated cystic to solid VS, the rate for tumor recurrence was significantly lower in GTR with 4% compared to STR with 50% (p = 0.042). Tumor control in cystic VS is superior in SURGERY, when treated with a high extent of resection grade, compared to SRS. Therapeutic response of SRS was worse in cystic compared to solid VS. However, when cystic VS was treated surgically, the rate of GTR is lower compared to the overall, and solid VS cohort. The significantly higher number of patients with relevant post-operative facial palsy in cystic VS is accredited to the increased tumor size not its sole cystic morphology. Cystic VS should be surgically treated in specialized centers.

Influence of Tumor Characteristics on Visual Field Outcomes After Pituitary Adenoma Surgery

BACKGROUND

There were few reports about the influence of tumor characteristics on the postoperative visual field outcomes after transsphenoidal surgery for pituitary adenoma. The purpose of this study was to explore the tumor characteristics that influenced perioperative visual field changes.

METHODS

Patients who underwent transsphenoidal surgery under a diagnosis of pituitary adenoma at the Kyoto University Hospital between April 2012 and December 2018 were retrospectively enrolled. Correlations among circumpapillary retinal nerve fiber layer thickness, preoperative and postoperative mean deviation (MD) of visual field, MD change after the surgery, and maximum tumor diameter were evaluated by measuring Pearson correlation coefficient. We evaluated the influences on postoperative MD using a generalized estimating equation for univariate and multivariate regression analyses. We also compared the characteristics of cystic and solid tumors.

RESULTS

Thirty-two eyes of 18 patients were included in this study (9 male and 9 female patients). Postoperative MD positively correlated with maximum tumor diameter only in multivariate regression {β = 0.22 (95% confidence interval [CI], 0.004-0.43), P = 0.046}, although maximum tumor diameter negatively correlated with postoperative MD in univariate regression (β = -0.16 [95% CI, -0.58 to 0.26], P = 0.46). In the investigation of perioperative MD changes, eyes with cystic tumors showed significantly better improvement those with solid tumors (8.93 ± 7.85 vs 0.18 ± 6.56 dB, P = 0.007).

CONCLUSIONS

Cystic and solid tumors show different characteristics of visual loss and visual field defects. The MD in eyes with cystic tumors improved significantly more than that in eyes with solid tumors.

Vestibular schwannoma with fluid-fluid levels mimicking aneurysm bone cyst

Of 6%-8%, cerebral tumors are intracranial schwannomas, also known as neurinomas, which frequently arise from the nerve sheath. Eighth cranial nerve (CN VIII), also known as the vestibulocochlear nerve, is the site of genesis of the majority of schwannomas, which account for 80%-90% of cerebellopontine angle tumors. In this paper, we intended to describe an uncommon cystic vestibular schwannoma with multiple fluid-fluid levels. Surgical excision was performed using the translabyrinthine approach. The report highlights schwannomas' adherence to and invasion of adjacent anatomical structures. We discuss a number of differential diagnoses, the pathophysiology of fluid-fluid levels, and the imaging features of cystic vestibular schwannomas.

Management and outcome of unusual pediatric brain tumors: challenges experienced at a tertiary care center of a developing country

PURPOSE

Primary brain tumors are the most frequent solid pediatric tumors, accounting for 40-50% of all cancers in children. Eighty to ninety percent of the 250,000 new cases of pediatric cancer each year are discovered in low and middle-income nations, where nearly 88 percent of the world's children reside. This article aims to emphasize the unusual presentation, management, and surgical outcome of complex pediatric brain tumors.

METHODS

We performed a retrospective study of patients who were admitted to the neurosurgery department with unusual pediatric brain tumors between March 1, 2019, and March 1, 2022. The study included pediatric patients up to age 18 years. We included those pediatric brain tumors whose (i) location was uncommon, or (ii) presented with unusual clinical presentation, or (iii) histopathology suggested to be a rare tumor, or (iv) radiological features were atypical.

RESULTS

We included 9 cases of rare unusual pediatric brain tumors. Three out of 9 cases required preoperative embolization due to its hypervascular nature on digital subtraction angiography (DSA). All patients underwent surgical excision within 24-48 h of tumor devascularization. One out of 9 cases died in follow-up period due to pleural effusion and distant metastasis to lungs.

CONCLUSION

Treatment considerations for unusual pediatric brain tumors include a comprehensive multidisciplinary approach, including community-based screening and proper referral system for early treatment, a variety of treatment modalities, and sophisticated follow-up strategy. Government shall work in coherence with tertiary centers to spread social awareness and provide various financial scheme to prevent treatment dropouts.

Long-term results of upfront, single-session Gamma Knife radiosurgery for large cystic vestibular schwannomas

Anecdotally, cystic vestibular schwannomas (cVSs) are regarded to have unpredictable biologic activity with poorer clinical results, and most studies showed a less favorable prognosis following surgery. While stereotactic radiosurgery (SRS) is a well-established therapeutic option for small- to medium-sized VSs, cVSs are often larger, thus making upfront SRS more complicated. The purpose of this retrospective study was to assess the efficacy and safety of upfront SRS for large cVSs. The authors reviewed the data of 54 patients who received upfront, single-session Gamma Knife radiosurgery (GKRS) with a diagnosis of large cVS (> 4 cm3). Patients with neurofibromatosis type 2, multiple VSs, or recurrent VSs and < 24 months of clinical and neuroimaging follow-up were excluded. Hearing loss (48.1%) was the primary presenting symptom. The majority of cVSs were Koos grade IV (66.7%), and the most prevalent cyst pattern was "mixed pattern of small and big cysts" (46.3%). The median time between diagnosis and GKRS was 12 months (range, 1-147 months). At GKRS, the median cVS volume was 6.95 cm3 (range, 4.1-22 cm3). The median marginal dose was 12 Gy (range, 10-12 Gy). The mean radiological and clinical follow-up periods were 62.2 ± 34.04 months (range, 24-169 months) and 94.9 ± 45.41 months (range, 24-175 months), respectively. At 2, 6, and 12 years, the tumor control rates were 100%, 95.7%, and 85.0%, respectively. Tumor shrinkage occurred in 92.6% of patients (n = 50), tumor volume remained stable in 5.6% of patients (n = 3), and tumor growth occurred in 1.9% of patients (n = 1). At a median follow-up of 53.5 months, the pre-GKRS tumor volume significantly decreased to 2.35 cm3 (p < 0.001). While Koos grade 3 patients had a greater possibility of attaining higher volume reduction, "multiple small thick-walled cyst pattern" and smaller tumor volumes decreased the likelihood of achieving higher volume reduction. Serviceable hearing (Gardner-Robertson Scale I-II) was present in 16.7% of patients prior to GKRS and it was preserved in all of these patients following GKRS. After GKRS, 1.9% of patients (n = 1) had new-onset trigeminal neuralgia. There was no new-onset facial palsy, hemifacial spasm, or hydrocephalus. Contrary to what was believed, our findings suggest that upfront GKRS seems to be a safe and effective treatment option for large cVSs.

Management of Sporadic Vestibular Schwannomas in Children—Volumetric Analysis and Clinical Outcome Assessment

Vestibular schwannomas (VS) usually manifest between the 5th and 8th decade of life. Most pediatric cases are associated with Neurofibromatosis type 2 and sporadic VS are rare in this age group. Few case series have been published. We report on our institutional series of sporadic VS in children. We included all cases between 2003 and 2021; 28 of 1635 patients harbored a sporadic VS and were younger than 21 years old. A retrospective review of clinical parameters and surgical data as well as outcomes was performed. All procedures were performed via a retrosigmoid approach. Preoperative imaging was assessed, and tumor volumetry was performed. Mean follow-up was 28 months, symptomatology was diverse. Most children and adolescents presented with hearing loss and tinnitus. All cases with multiple preoperative magnetic resonance imaging scans showed volumetric tumor growth between 1 and 18%/month (mean 8.9 ± 5.6%). Cystic tumor morphology and bone erosion was seen in larger tumors. Gross total resection was possible in 78% of patients and no recurrence was observed. All patients with subtotal resection showed tumor regrowth. Sporadic VS in children are rare and present with a high clinical variability. Surgical resection is the primary therapy and is feasible with favorable results comparable to the adult age group.

Endoscope-Assisted Retrosigmoid Approach for Vestibular Schwannomas With Intracanalicular Extensions: Facial Nerve Outcomes

Objective

To explore the role of neuroendoscope assistance during surgical resection of the intracanalicular portion of vestibular schwannomas via the retrosigmoid approach and the subsequent early facial nerve outcomes.

Methods

Patients of vestibular schwannoma with intracanalicular extensions undergoing retrosigmoid dissection at a single institution were retrospectively analyzed in this study. Several surgical techniques were applied to ensure maximal and safe removal of tumors. Tumors extending less than 10 mm into the internal acoustic canal (IAC) were classified as Grade A, while those extending over 10 mm into IAC were taken as Grade B. Neuroendoscope was applied at the end of microscopic phase to search for potential remnants for Grade B tumors. Absolute tumor extension was defined and measured. House and Brackmann (HB) scale was used to evaluate immediate CN VII outcomes.

Results

Of the 61 patients, there were 38 females and 23 males. A total of 18 (29.51%) cases were Koos Grade II, 12 (19.67%) cases Koos Grade III, and 31 (50.82%) cases Koos Grade IV. There were 38 cases (62.30%) of Grade A and 23 cases (37.70%) of Grade B. Gross total resection was achieved in 60 cases (98.36%). Four cases of intracanalicular remnants were detected and completely removed under endoscopic visualizations. There was a significantly higher proportion (17%, p = 0.02) of intracanalicular remnants in Grade B than Grade A. CN VII and VIII were anatomically preserved in all cases. A total of 55 cases (90.16%) retained good (HB Grades 1 and 2) facial nerve outcomes.

Conclusions

In Grade B vestibular schwannomas, after maximal microsurgical removal, endoscopic evaluation of the intracanalicular portion revealed residual tumors in 17% of the patients. Hence endoscopic evaluation of the potential intracanalicular remnants for tumor extending over 10 mm within IAC (Grade B) is recommended.