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Dayawansa, Sam

https://orcid.org/0000-0002-2528-3145

Mayo Clinic

Department of Neurosurgery, John D. Archbold Memorial Hospital, Thomasville, Georgia;

Citations 6

Active surveillance versus stereotactic radiosurgery for Koos grade I and II vestibular schwannoma in patients aged 60 years or older
Ishaque, Mariam , Tos, Salem M., Hajikarimloo, Bardia, Fuentes, Angelica M. , Abou-Al-Shaar, Hussam, Peker, Selcuk, Samanci, Yavuz, Pelcher, Isabelle , Begley, Sabrina , Goenka, Anuj, Schulder, Michael , Tourigny, Jean-Nicolas, Mathieu, D, Hamel, Andréanne, Briggs, Robert G., Yu, Cheng , Zada, Gabriel, Giannotta, S L, Palque, Sarai, Kumar, S Praveen, Kumar, Narendra, Rogowski, Brandon, Shepard, Matthew J., Trifiletti, Daniel M., Dayawansa, Sam, Vasconcellos, Fernando De Nigris, Bernstein, Kenneth , Schnurman, Zane, Alzate, Juan, Kondziolka, Douglas, Sheehan, Jason P., Johnson, Bryan A, Mantziaris, Georgios , Tos, Salem M , Hajikarimloo, Bardia , Bin-Alamer, Othman , Abou‐Al‐Shaar, Hussam , Peker, Selçuk , Samancı, Yavuz , Goenka, Anuj , Mathieu, David , Zada, Gabriel , Giannotta, Steven L. , Speckter, Herwin , Tripathi, Manjul , Kaur, Rupinder , Rogowski, Brandon, Johnson, Bryan A., Trifiletti, Daniel M. , Warnick, Ronald E. , Dayawansa, Sam , Mashiach, Elad , Vasconcellos, Fernando De Nigris , Schnurman, Zane , Alzate, Juan Diego , Kondziolka, Douglas, Sheehan, Jason P.

Journal of Neurosurgery | May 16, 2026 | Volume: No volume available | Issue: No issue available | Pages: 1-11

10.3171/2026.1.jns242756 Get It

OBJECTIVE The aim of this study was to evaluate freedom from tumor progression and clinical outcomes in older adults with small- to medium-sized vestibular schwannoma (VS) managed by observation versus stereotactic radiosurgery (SRS) to better inform optimal management in this patient population. METHODS In this international multicenter study, patients aged ≥ 60 years with Koos grade I or II VS managed by observation or SRS were retrospectively reviewed. Propensity score matching was conducted using patient characteristics, tumor size, and hearing assessments. Outcome measures of freedom from tumor progression, serviceable hearing preservation (SHP), and neurological function (tinnitus, vestibulopathy, House-Brackmann grade, and trigeminal nerve function) were assessed for both groups. RESULTS The observation and SRS groups each comprised 51 matched patients (median age 68 years for both). Ipsilateral serviceable hearing was observed at presentation for 35 patients in each group. The median follow-up duration was 39 months in the observation group versus 27 months in the SRS group (p = 0.5). Tumor progression was significantly lower with SRS than with observation (2% vs 52.9%, p < 0.001). The rate of 5-year freedom from tumor progression was 100% in the SRS group versus 43% (95% CI 29%–64%) in the observation group. The rate of 10-year freedom from tumor progression was 90% (95% CI 73%–100%) in the SRS group versus 20% (95% CI 8.5%–49%) in the observation group. At the last follow-up, hearing loss occurred in 42.9% of the observation group and 51.4% of those who underwent SRS (p = 0.5). The 3-year SHP rate was 68% (95% CI 53%–88%) versus 65% (95% CI 49%–85%) (p = 0.8), and the 5-year SHP rate was 53% in both groups (95% CI 36%–78% in the observation group and 95% CI 35%–79% in the SRS group, p = 0.8). The composite endpoint of tumor progression and/or worsened neurological outcome, including hearing loss, tinnitus, vestibulopathy, facial nerve dysfunction (House-Brackmann grade), or trigeminal dysfunction, demonstrated a significantly lower rate in the SRS group (17.6%) compared with the observation group (66.7%) (p < 0.001). CONCLUSIONS SRS in older patients for management of Koos grade I or II VS resulted in significantly superior rates of freedom from tumor progression, comparable hearing preservation rates, and significantly higher rates of favorable overall radiographic and neurological outcomes than observation alone. Compared with observation, SRS might be the preferred management option in this patient population.
Stereotactic radiosurgery versus observation for intracranial low-grade dural arteriovenous fistulas
Becerril‐Gaitan, Andrea , Peesh, Pedram , Liu, Collin, Lee, Cheng-chia, Niranjan, Ajay , Lunsford, L. Dade , Wei, Zhishuo , Hoang, A, Sheehan, Jason P. , Dayawansa, Sam , Samanci, Yavuz, Starke, Robert M. , Ikeda, Go , Kano, Hideyuki , Wang, Qian , Welch, Babu G. , O’Con, Jennifer, Lanzino, Guiseppe, Brinjikji, Waleed , Hayakawa, M. , Gross, Bradley A. , Albuquerque, Felipe C , Lawton, Michael T., Kim, Louis J. , Alaraj, Ali , Winkler, Ethan A. , Chalouhi, Nohra , Bulters, Diederik , Durnford, Andrew , Satomi, Junichiro, Tada, Yoshiteru , Dijk, J. Marc C. van , Potgieser, Adriaan R. E., Laurent, Dimitri , Bahmani, Brigette, Zipfel, Gregory J. , Samancı, Yavuz , Tripathi, Manjul , Welch, Babu , Du, Rose , Lai, Rosalind , Gross, Bradley , Levitt, Michael R , Alaraj, Ali , van DijK, J Marc C , Osbun, Joshua W , Bulters, Diederik O , Yang, Huai‐Che , Peker, Selçuk , Abdelsalam, Ahmed , Kondziolka, Douglas , Bernstein, Kenneth, Ming, Ying, Liščák, Roman , May, Jaromír , Li, Wen , O’Con, Jennifer, Amin-Hanjani, Sepideh , Nguyen, Quang, Samaniego, Edgar A , Lai, Pui Man Rosalind , Derdeyn, Colin P. , Abla, Adib A. , Lawton, Michael T. , Kim, Louis J. , Levitt, Michael R. , Hoh, Brian L. , Chen, Ching‐Jen

Journal of Neurology, Neurosurgery & Psychiatry | June 6, 2025 | Volume: 96 | Issue: 11 | Pages: 1117-1125

10.1136/jnnp-2024-335675 Get It

Background Given the low haemorrhagic risk of intracranial low-grade dural arteriovenous fistulas (dAVFs), the benefits of routine intervention remain controversial. This study compares patient outcomes treated with stereotactic radiosurgery (SRS) versus conservative management. Method Multicentre retrospective analysis of the Consortium for Dural Arteriovenous Fistula Outcomes Research and the International Radiosurgery Research Foundation data. Inclusion criteria were (1) intracranial low-grade dAVF diagnosed by catheter-based angiography, (2) no prior dAVF-related haemorrhage and (3) management with upfront SRS (intervention group) or conservative management (observation group). The primary outcome was symptomatic improvement. Secondary outcomes included dAVF obliteration, up-conversion, haemorrhage, improvement and favourable modified Rankin Scale (mRS) at follow-up. Results 304 patients with a mean age of 56 years (SD 13.5) and a follow-up of 46.7 months (SD 45.5) were included. 135 (44.4%) were managed conservatively and 169 (55.6%) had upfront SRS. Compared with the observation group, symptomatic and mRS Score improvement (≥1-point decrease in baseline score) was more likely in the intervention group (95.1% vs 58.5%; OR=13.75 (5.61–33.69) and 37.0% vs 24.0%; OR=1.85 (1.09–3.15), respectively). These findings remained significant after multiple imputation and propensity score matching. Remaining outcomes were similar between groups. The all-cause mortality rate was 5.4% (n=16), unrelated to the dAVF or treatment. Five (3.0%) SRS-related complications were reported and resolved during the follow-up period. Conclusions SRS was associated with increased symptomatic and mRS Score improvement for low-grade dAVFs compared with conservative management. SRS had a low complication risk and did not appear to alter dAVF obliteration or haemorrhage. Future prospective trials on SRS as a first-line intervention for symptomatic low-grade dAVFs should be considered.
Vestibular Schwannoma Koos Grade I International Study of Active Surveillance Versus Stereotactic Radiosurgery: The VISAS-K1 Study
Bin-Alamer, Othman , Peker, Selçuk , Samancı, Yavuz , Pelcher, Isabelle , Begley, Sabrina , Goenka, Anuj , Schulder, Michael , Tourigny, Jean-Nicolas, Hamel, Andréanne, Briggs, Robert G. , Yu, Cheng , Zada, Gabriel , Giannotta, Steven L., Palque, Sarai, Kumar, Narendra , Rogowski, Brandon, Shepard, Matthew J., Warnick, Ronald E. , Dayawansa, Sam , Vasconcellos, Fernando De Nigris , Bernstein, Kenneth , Sheehan, Jason P. , Johnson, Bryan A, Sheehan, Jason , Bin-Alamer, Othman , Abou‐Al‐Shaar, Hussam , Mathieu, David , Giannotta, Steven L. , Speckter, Herwin , Tripathi, Manjul , Kumar, Saurabh , Kaur, Rupinder , Johnson, Bryan A., Trifiletti, Daniel M. , Mashiach, Elad , Schnurman, Zane , Alzate, Juan Diego , Kondziolka, Douglas

Neurosurgery | November 6, 2024 | Volume: 96 | Issue: 1 | Pages: 41-49

10.1227/neu.0000000000003215 Get It

BACKGROUND AND OBJECTIVE: This investigation evaluates the safety and efficacy of stereotactic radiosurgery (SRS) vs observation for Koos grade I vestibular schwannomas (VS). METHODS: In a multicenter study, we retrospectively analyzed data of patients with Koos grade I VS who underwent SRS (SRS group) or were observed (observation group). Propensity score matching was used to equilibrate demographics, tumor size, and audiometric data across groups. The outcome analyzed included tumor control, preservation of serviceable hearing, and neurological function. RESULTS: The study matched 142 patients, providing a median follow-up period of 36 months. SRS significantly enhanced tumor control compared with observation, with a 100% control rate at both 5- and 8-year marks in the SRS group vs 48.6% and 29.5% in the observation group at the same time intervals, respectively ( P < .001). Preservation of serviceable hearing outcomes between groups showed no significant difference at 5 and 8 years, ensuring a comparable quality of auditory function (SRS 70.1% vs observation 53.4% at 5 years; P = .33). Furthermore, SRS was associated with a reduced likelihood of tinnitus (odds ratio [OR] = 0.46, P = .04), vestibular dysfunction (OR = 0.17, P = .002), and overall cranial nerve dysfunction (OR = 0.49, P = .03) at last follow-up. CONCLUSION: SRS management of patients with Koos grade I VS was associated with superior tumor control and reduced odds for cranial nerve dysfunction, while not compromising hearing preservation compared with observation. These findings support the safety and efficacy of SRS as a primary care approach for this patient population.
Vestibular Schwannoma Koos Grade II International Study of Active Surveillance Versus Stereotactic Radiosurgery: The VISAS-K2 Study
Bin-Alamer, Othman , Peker, Selçuk , Samanci, Yavuz, Pelcher, Isabelle , Begley, Sabrina , Goenka, Anuj , Schulder, Michael , Tourigny, Jean-Nicolas, Hamel, Andréanne, Briggs, Robert G. , Yu, Cheng , Zada, Gabriel , Giannotta, Steven L., Palque, Sarai, Kumar, Narendra , Rogowski, Brandon, Shepard, Matthew J., Warnick, Ronald E. , Dayawansa, Sam , Vasconcellos, Fernando De Nigris , Bernstein, Kenneth , Sheehan, Jason P. , Samancı, Yavuz , Johnson, Bryan A, Sheehan, Jason , Bin-Alamer, Othman , Abou‐Al‐Shaar, Hussam , Mathieu, David , Giannotta, Steven L. , Speckter, Herwin , Tripathi, Manjul , Kumar, Saurabh , Kaur, Rupinder , Johnson, Bryan A., Trifiletti, Daniel M. , Mashiach, Elad , Schnurman, Zane , Alzate, Juan Diego , Kondziolka, Douglas

Neurosurgery | November 6, 2024 | Volume: 96 | Issue: 1 | Pages: 50-58

10.1227/neu.0000000000003216 Get It

BACKGROUND AND OBJECTIVES: This study assessed the efficacy and safety of stereotactic radiosurgery (SRS) in comparison with watchful waiting for managing Koos grade II vestibular schwannomas (VS). METHODS: A retrospective, multicentric analysis was conducted, focusing on patients with Koos grade II VS who either received SRS (SRS group) or were observed (observation group). To ensure comparability between groups, propensity score matching was used, including factors such as demographic characteristics, tumor dimensions, and hearing assessments. The primary end points examined were tumor control, maintenance of serviceable hearing, and neurological outcomes. RESULTS: A total of 92 patients were equally matched across both cohorts, with a median follow-up of 37 months for the SRS group and 27.5 months for those observed. The SRS cohort exhibited superior tumor control over observation across 3, 5, and 8 years, achieving a 100% control rate vs 47.9%, 40.1%, and 34.3% for the observation group at these time intervals, respectively ( P < .001). Serviceable hearing preservation rates were comparable between the 2 groups throughout 3, 5, and 7 years (72.9% for SRS vs 65.4% for observation at 3 years; P = .86). Moreover, SRS management correlated with a lower incidence of vestibular symptoms (odds ratio = 0.11, P = .002), with no significant disparity in the deterioration of cranial nerve (CN) V or CN VII functions. Notably, the likelihood of experiencing any CN impairment was significantly diminished in the SRS cohort (odds ratio = 0.47, P = .04). CONCLUSION: For patients with Koos grade II VS, SRS offers superior tumor control rate and a lower risk of CN dysfunction without sacrificing hearing preservation.
Facial Nerve Schwannoma Treatment with Stereotactic Radiosurgery (SRS) versus Resection followed by SRS: Outcomes and a Management Protocol
Dayawansa, Sam , Mantziaris, Georgios , Mehta, Gautam U. , Leković, Gregory P. , Mathieu, David , Reda, Wael A. , Lee, Cheng-chia, Barnet, Gene, Lunsford, L. Dade , Sheehan, Jason P. , Mehta, Gautam U , Mathieu, David , Trifiletti, Daniel M , Mantziaris, Georgios , Dumot, Chloé , Kondziolka, Douglas , Reda, Wael A. , Liščák, Roman , Kaufmann, Anthony M. , Trifiletti, Daniel M.

Journal of Neurological Surgery Part B: Skull Base | December 1, 2022 | Volume: 85 | Issue: 01 | Pages: 075-080

10.1055/a-1990-2861 Get It

Abstract Background Stereotactic radiosurgery (SRS) and resection are treatment options for patients with facial nerve schwannomas without mass effect. Objective This article evaluates outcomes of patients treated with SRS versus resection + SRS. Method We retrospectively compared 43 patients treated with SRS to 12 patients treated with resection + SRS. The primary study outcome was unfavorable combined endpoint, defined as worsening or new clinical symptoms, and/or tumor radiological progression. SRS (38.81 ± 5.3) and resection + SRS (67.14 ± 11.8) groups had similar clinical follow-ups. Results At the time of SRS, the tumor volumes of SRS (mean ± standard error; 1.83 ± 0.35 mL) and resection + SRS (2.51 ± 0.75 mL) groups were similar. SRS (12.15 ± 0.08 Gy) and resection + SRS (12.16 ± 0.14 Gy) groups received similar radiation doses. SRS group (42/43, 98%) had better local tumor control than the resection + SRS group (10/12, 83%, p = 0.04). Most of SRS (32/43, 74%) and resection + SRS (10/12, 83%) group patients reached a favorable combined endpoint following SRS (p = 0.52). Considering surgical associated side effects, only 2/10 patients of the resection + SRS group reached a favorable endpoint (p < 0.001).Patients of SRS group, who are > 34 years old (p = 0.02), have larger tumors (> 4 mL, 0.04), internal auditory canal (IAC) segment tumor involvement (p = 0.01) were more likely to reach an unfavorable endpoint. Resection + SRS group patients did not show such a difference. Conclusion While resection is still needed for larger tumors, SRS offers better clinical and radiological outcomes compared to resection followed by SRS for facial schwannomas. Younger age, smaller tumors, and non-IAC situated tumors are factors that portend a favorable outcome.