A prediction model for recurrence after translabyrinthine surgery for vestibular schwannoma: toward personalized postoperative surveillance

Purpose The aim of this study is to compute and validate a statistical predictive model for the risk of recurrence, defined as regrowth of tumor necessitating salvage treatment, after translabyrinthine removal of vestibular schwannomas to individualize postoperative surveillance. Methods The multivariable predictive model for risk of recurrence was based on retrospectively collected patient data between 1995 and 2017 at a tertiary referral center. To assess for internal validity of the prediction model tenfold cross-validation was performed. A ‘low’ calculated risk of recurrence in this study was set at < 1%, based on clinical criteria and expert opinion. Results A total of 596 patients with 33 recurrences (5.5%) were included for analysis. The final prediction model consisted of the predictors ‘age at time of surgery’, ‘preoperative tumor growth’ and ‘first postoperative MRI outcome’. The area under the receiver operating curve of the prediction model was 89%, with a C-index of 0.686 (95% CI 0.614–0.796) after cross-validation. The predicted probability for risk of recurrence was low (< 1%) in 373 patients (63%). The earliest recurrence in these low-risk patients was detected at 46 months after surgery. Conclusion This study presents a well-performing prediction model for the risk of recurrence after translabyrinthine surgery for vestibular schwannoma. The prediction model can be used to tailor the postoperative surveillance to the estimated risk of recurrence of individual patients. It seems that especially in patients with an estimated low risk of recurrence, the interval between the first and second postoperative MRI can be safely prolonged.

Absence of residual tumor tissue after Gamma Knife radiosurgery followed by resection of a vestibular schwannoma: illustrative case

BACKGROUND Late pathology after vestibular schwannoma radiosurgery is uncommon. The authors presented a case of a resected hemorrhagic mass 13 years after radiosurgery, when no residual tumor was found. OBSERVATIONS A 56-year-old man with multiple comorbidities, including myelodysplastic syndrome cirrhosis, received Gamma Knife surgery for a left vestibular schwannoma. After 11 years of stable imaging assessments, the lesion showed gradual growth until a syncopal event occurred 2 years later, accompanied by progressive facial weakness and evidence of intralesional hemorrhage, which led to resection. However, histopathological analysis of the resected specimen showed hemorrhage and reactive tissue but no definitive residual tumor. LESSONS This case demonstrated histopathological evidence for the role of radiosurgery in complete elimination of tumor tissue. Radiosurgery for vestibular schwannoma carries a rare risk for intralesional hemorrhage in select patients.

Dispersed Bone Spicules as a Cause of Postoperative Headache after Retrosigmoid Vestibular Schwannoma Surgery: A Myth?

Objectives Dispersion of bone dust in the posterior fossa during retrosigmoid craniectomy for vestibular schwannoma (VS) resection could be a source of meningeal irritation and lead to development of persistent postoperative headaches (POH). We aim to determine risk factors, including whether the presence of bone spicules that influence POH after retrosigmoid VS resection. Design Present study is a retrospective case series. Setting The study was conducted at a tertiary skull-base referral center. Participants Adult patients undergoing VS resection via a retrosigmoid approach between November 2017 and February 2020 were included for this study. Main Outcome Measures Development of POH lasting ≥ 3 months is the primary outcome of this study. Results Of 64 patients undergoing surgery, 49 had complete data (mean age, 49 years; 53% female). Mean follow-up time was 2.4 years. At latest follow up, 16 (33%) had no headaches, 14 (29%) experienced headaches lasting <3 months, 19 (39%) reported POH lasting ≥3 months. Twenty-seven (55%) patients had posterior fossa bone spicules detectable on postoperative computed tomography (CT). Age, gender, body mass index, length of stay, tumor diameter, size of craniectomy, the presence of bone spicules, or the amount of posterior petrous temporal bone removed from drilling did not differ significantly between patients with POH and those without. On multivariate logistic regression, patients with POH were less likely to have preoperative brainstem compression by the tumor (odds ratio [OR] = 0.21, p = 0.028) and more likely to have higher opioid requirements during hospitalization (OR = 1.023, p = 0.045). Conclusion The presence of bone spicules in the posterior fossa on postoperative CT did not contribute to headaches following retrosigmoid craniectomy approach for VS resection.

An Evidence-Based Vestibular Schwannoma Surgical Outcome Grading Scale for Large-to-Giant Vestibular Schwannomas

Objectives: The objective of this study was to determine the relationship between facial nerve function and extent of resection (EOR) as outcomes in the surgical management of large vestibular schwannoma (VS) (≥ 2.5 cm maximal) and evaluate use of a new grading system that incorporates both outcomes.Methods: We conducted a systematic review of the electronic databases using different MeSH terms from 1990 to 2021. 5,623 patients from 56 studies were found appropriate for inclusion in the study. Surgical approach was reported in 5,144 patients, including translabyrinthine approach (TL) in 43.3% (n=2,225), retrosigmoid (RS) approach in 56.3% (n=2,899), retrolabyrinthine (RL) approach in 0.3% (n=16), and extended translabyrinthine (EX) approach in 0.1% (n=4). The proposed VS Grading System defines outcomes of gross total resection (GTR), near total resection (NTR) and subtotal resection (STR) with good facial nerve function [House-Brackmann (HB) Grade I-II] as Classes A, B and C respectively. Those with poor facial nerve outcome (HB III-VI) are graded as Classes D, E and F, respectively. Results:. As expected, patients with STR had a higher likelihood of better facial nerve outcomes (HB I-II) compared to NTR [Odds Ratio (OR): 7.30, 95%CI: 2.45-12.1, p=0.004] and GTR (OR: 9.61, 95%CI: 3.61-15.6, p=0.002), while NTR had better facial nerve outcome than GTR (OR: 1.5, 95%CI: 1.14-4.6, p<0.0001). A Class A result, representing the best possible outcome, was obtained in 55.8% of TL vs. 49.4% undergoing RS approach. Conclusion: Complete surgical resection with preservation of facial nerve function is the gold standard for large VS.