OBJECTIVE:Vestibular schwannomas (VSs) treated with stereotactic radiosurgery (SRS) often show transient loss of central tumor enhancement. We hypothesized that this loss of enhancement may correlate with better tumor control on follow-up imaging. METHODS:We evaluated 198 consecutive patients from a single center who met eligibility criteria. Tumor volumes on the pre-SRS and post-SRS scans were quantified along with regions of loss of enhancement on the first post-SRS study. The latter was correlated with tumor volumes at follow-up, radiation isocenter density, and loss of serviceable hearing. RESULTS:For the entire cohort, the median loss of enhancement on the first post-SRS scan was 14% (IQR: 6 to 25) and median rate of change in tumor volume was -4.5% per year (IQR: -10.5 to 1.5). Percent loss of central enhancement showed significant negative correlation with tumor growth not only for the entire cohort (correlation coefficient: -0.18, P =0.01), but also for the subset of patients who had available imaging until at least 2 years (n=185) and 4 years (n=179) post-SRS. Loss of enhancement also strongly correlated positively with tumor volumes and number of radiation isocenters and negatively with isocenter density. Finally, patients with greater percent loss of enhancement had an increased likelihood of progression to non-serviceable hearing, although this association was not statistically significant. CONCLUSIONS:These findings suggest that loss of central tumor enhancement in VSs post-SRS may be associated with improved tumor control.

Objectives Cerebellopontine angle (CPA) tumors, including vestibular schwannomas (VS), often require microsurgical resection. These are typically surgical procedures performed by co-surgeons, and some controversy and confusion exist regarding use of common procedural terminology (CPT) codes for billing, given the American Medical Association (AMA) describes two distinct coding sets for such cases. This investigation endeavored to: (1) Comprehensively review all surgical coding options; (2) instruct on application; and (3) explore contemporary coding trends among surgeons. Design A multi-disciplinary task force (otologist/neurotologists and neurosurgeons) performed direct correspondence with various surgical societies, private consultancies, and the AMA. Survey instruments were distributed to active surgeons. Setting Investigational period: 2022 to 2025. Survey instruments distributed at the 2023 American Neurotology Society (ANS) Fall Meeting. Participants ANS, American Academy of Otolaryngology (AAO-HNSF), and the North American Skull Base Society (NASBS) representatives. Outcomes Measures Usage rate for CPT code sets (percentage of responders). Results Two CPT coding systems are currently accepted for surgical management of CPA tumors. The traditional/legacy codes (Indicator-2) allow use of co-surgery modifiers (-62). The newer approach/resection codes (skull base codes; Indicator-1) restrict modifier use. The history, application, and controversies surrounding the codes are detailed herein. About 40% of surgeons reported use of the traditional codes, while 45 to 49% use the skull base codes. Response rate was 31% of the active ANS membership in 2023. Conclusion The AMA recognizes two CPT code sets for surgical management of CPA tumors. Both are appropriate, if properly applied. Contemporary surgeons likely utilize the sets in equal proportions.

BACKGROUND AND OBJECTIVES:Contemporary skull base surgeons must understand transcranial and endoscopic endonasal approaches to the petrous apex (PA). We provide an anatomic overview and comparison of main approaches to the PA through illustrative anatomic dissections. METHODS:On 10 sides of 5 specimens, transcranial approaches to the PA including the anterior petrosal, transcochlear, and retrosigmoid with suprameatal extension were performed. For endoscopic endonasal approaches, the transclival approach was performed in the midline of 5 specimens and its contralateral transmaxillary extension was performed on 10 sides. RESULTS:The anterior petrosal approach offers an anterolateral view of the PA bounded by petrous ridge posteromedially, internal auditory canal posterolaterally, greater superficial petrosal nerve anterolaterally, and lateral boundary of cranial nerve V, the Gasserian ganglion, and V3 anteromedially; it exposes the middle fossa and, once the PA is removed, the superomedial cerebellopontine angle. The transcochlear approach affords a lateral view of the PA defined medially and inferiorly by inferior petrosal sinus, posteriorly by posterior fossa dura, anteriorly by the petrous internal carotid artery, and superiorly by the superior petrosal sinus and middle fossa dura. Through a retrosigmoid approach, the PA is bounded by the superior petrosal sinus superiorly, the sagittal plane of cranial nerve VI medially, and the axial and sagittal plane of the internal auditory canal porus inferiorly and laterally, respectively. It affords a panoramic view of the posterior fossa and access to Meckel's cave after PA drilling. Endoscopic endonasal approaches target the anteromedial PA, and it is demarcated by a triangle consisting of cranial nerve VI posterolaterally, the paraclival segment of the internal carotid artery anteriorly, and the petroclival synchondrosis inferiorly and medially. The addition of the contralateral transmaxillary approach enhances lateral access up to the internal auditory canal. CONCLUSION:We provide a comprehensive overview of the main approaches to the PA through illustrative anatomic dissections and representative cases.

OBJECTIVE:The minimal important difference (MID) and minimal important change (MIC) are two metrics that bridge the gap between statistical significance and clinical relevance and are critical to managing clinical decisions and conducting clinical research. The objective of this study was to define MIDs to evaluate cross-sectional differences among groups and to define MICs to evaluate longitudinal within-patient changes for the Mayo Clinic Vestibular Schwannoma Quality of Life (VSQOL) Index. METHODS:Anchor-based methods were used to define MIDs and MICs for the VSQOL Index domain scores, which range from 0 to 100 points, for a national cohort of 1050 patients with sporadic vestibular schwannoma, 644 of whom completed the VSQOL Index twice approximately 1 year apart. RESULTS:The median of the MID estimates for the VSQOL Index domains were: hearing problems (17, IQR 12.5-21); dizziness and imbalance (21, IQR 18-23); pain, discomfort, and tinnitus (19.5, IQR 15-23.5); problems with face or eyes (18, IQR 17-28); impact on physical, emotional, and social well-being (19.5, IQR 14.5-23.5); difficulty with thinking and memory (23.5, IQR 18.5-28.5); global quality of life (12, IQR 8-16); and satisfaction or regret (13.5, IQR 7-17). MIC estimates for the hearing problems and satisfaction and regret domains were not obtained because the correlations between these domain scores and their associated anchors were not sufficiently strong. The MIC estimates (minimum and maximum) for the remaining domains were: dizziness and imbalance (7.2 and 8.3); pain, discomfort, and tinnitus (8.3 and 8.5); problems with face or eyes (7.0 and 7.4); impact on physical, emotional, and social well-being (2.1 and 8.0); and difficulty with thinking and memory (12.9 and 15.0). The median of the MIC estimates for global quality of life was 5.2 (IQR 3.7-5.6). CONCLUSIONS:The MIDs and MICs reported herein provide a framework to interpret quality-of-life benefit or harm cross-sectionally among groups and longitudinally within patients. Moving forward, these values should be considered when interpreting studies using the VSQOL Index to assess disease-specific quality of life in patients with sporadic vestibular schwannoma.

Objective: To compare disease-specific quality of life (QOL) among patients with sporadic vestibular schwannoma (VS) by tumor management strategy using the recently developed and validated Mayo Clinic VSQOL Index relative to established minimal important difference (MID) thresholds. Study design: Cross-sectional cohort. Setting: Acoustic Neuroma Association and tertiary care center. Patients: Adults with sporadic VS. Interventions: Microsurgery, radiation, or observation. Main outcome measures: VSQOL Index scores were compared by tumor management strategy adjusting for age, sex, setting, tumor size at diagnosis, and duration of follow-up. Scores range from 0 to 100; higher scores indicate better QOL. Results: Of the 652 patients included, 333 (51%) were managed with microsurgery, 175 (27%) with radiation, and 144 (22%) with observation. The mean (SD) duration of follow-up was 6.2 (2.7) years. Global QOL adjusted mean scores (95% CI) differed significantly ( P <0.001) by management group: 70 (67-72) for microsurgery, 73 (70-77) for radiation, and 79 (75-83) for observation. Hearing Problems ( P <0.001), Dizziness and Imbalance ( P <0.001), Problems with Face or Eyes ( P <0.001), and Difficulty with Thinking and Memory ( P =0.03) domain scores also differed significantly by group. Pairwise comparisons that exceeded at least the lower bound of published MIDs included Global QOL scores (microsurgery versus observation) and Hearing Problems scores (microsurgery and radiation versus observation). Conclusions: At a mean follow-up of 6.2 years, several notable statistically and clinically significant differences in QOL were identified. These findings may be used to guide patient counseling regarding management options and require validation in future prospective studies.

OBJECTIVE:To evaluate hearing outcomes after treatment with stereotactic radiosurgery (SRS) for sporadic vestibular schwannoma (VS) among patients with baseline 100% word recognition scores (WRS). STUDY DESIGN:Historical cohort. SETTING:Tertiary academic medical center. PATIENTS:Patients with 100% WRS on audiometric testing at initial treatment with SRS. INTERVENTIONS:Gamma Knife SRS. MAIN OUTCOME MEASURES:Rate of maintaining serviceable hearing (SH), defined as American Academy of Otolaryngology-Head and Neck Surgery hearing class A or B. RESULTS:In total, 125 patients had 100% WRS at SRS for sporadic VS. Median age at SRS was 56 years (IQR: 51 to 62) and median pure tone average (PTA) at SRS was 20 dB HL (IQR: 13 to 31). Sixty-eight patients progressed to non-SH at a median of 3.4 years after SRS (IQR: 1.0 to 8.6); the median duration of follow-up for the 57 patients who maintained SH was 5.1 years (IQR: 2.8 to 9.6). Rates of maintaining SH (95% CI, number still at risk) at 1, 3, 5, 7, and 10 years after SRS were 88% (82 to 94, 101), 75% (68 to 84, 81), 61% (53 to 71, 55), 58% (49 to 68, 43), and 44% (35 to 56, 26), respectively. Each 10-dB HL increase in PTA at SRS was associated with a 52% increased risk of progression to non-SH (hazard ratio: 1.52, 95% CI: 1.24-1.87, P <0.001). CONCLUSIONS:Despite having 100% pretreatment WRS, most patients with sporadic VS treated with SRS experienced clinically significant hearing decline over time. Even among this cohort of patients with excellent baseline hearing, at 10 years after treatment, only 44% of patients maintained SH.

OBJECTIVE:Quality of life (QOL) is an important consideration in vestibular schwannoma (VS) patients when assessing management options. Understanding sex-based differences in QOL may facilitate patient counseling. STUDY DESIGN:Prospective cohort. SETTING:Tertiary academic medical center and Acoustic Neuroma Association. PATIENTS:Sporadic VS patients. INTERVENTIONS:Observation, microsurgery, or radiation. MAIN OUTCOME MEASURES:Penn Acoustic Neuroma Quality of Life (PANQOL) scores. RESULTS:A total of 481 patients were analyzed. In the observation group, women reported worse anxiety, facial function, and total PANQOL scores at baseline. At follow-up, men declined more in facial function (-5 vs. +3, P =0.01). For microsurgery, women reported worse facial function and balance scores at baseline. At follow-up, men declined more in facial function (-16 vs. -3, P <0.001), balance (-7 vs. +2, P =0.04), energy (-4 vs. +5, P =0.03), and total (-5 vs. +2, P =0.02) PANQOL scores. For radiation, women reported worse anxiety, balance, pain, and total scores at baseline. At follow-up, anxiety improved in women but worsened in men (+5 vs. -6, P =0.008). Sex-based differences exceeding the minimally important difference thresholds established for the PANQOL were observed for the following: anxiety at baseline in the observation group, anxiety and pain at baseline in the radiation group, and change in anxiety from baseline to follow-up in the radiation group. CONCLUSIONS:Women had worse anxiety, balance, facial function, pain, and overall QOL at baseline assessed using the PANQOL, whereas men declined more with treatment and observation. The largest difference in PANQOL change between sexes occurred after microsurgery, with men experiencing greater losses in facial function, balance, energy, and total scores.

OBJECTIVE:Management of vestibular schwannoma (VS) remains controversial. Very small VSs represent a pivotal group: on one hand, they pose the least risk to the patient from the perspective of being small; yet, not recommending treatment may result in missing a critical window for achieving the best outcome. This debate fundamentally hinges on whether treatment improves upon the natural history of the disease. There is an unproven assumption that very small tumors behave similarly to the broader observed population. To address this central question, we conducted a multicenter retrospective review to compare the natural history of tumor growth and hearing for patients with very small VS (1-3 mm) with a referent cohort with larger tumors. METHODS:All patients diagnosed with sporadic VS 1-3 mm were reviewed at 3 large skull base referral centers and compared with a referent cohort of patients with tumors > 3 mm. Tumor growth-free survival rates, treatment-free survival rates, and rates of maintenance of class A, B, or C hearing were estimated using the Kaplan-Meier method. RESULTS:In total, 123 patients with very small VS and a referent cohort of 326 patients were studied. Seventeen patients with very small VS experienced tumor growth at a median of 3.2 years after diagnosis (IQR 2.6-5.1), demonstrating a median growth rate of 1.0 mm per year (IQR 0.9-1.8). In comparison, 167 of the patients in the referent cohort experienced tumor growth at a median of 1.7 years after diagnosis (IQR 0.8-3.1). Tumor growth-free survival rates (95% CI, number still at risk) at 5 years after diagnosis for the 2 cohorts were 84% (75-93, 39) and 45% (40-52, 100), respectively (p < 0.001). Six patients with very small VS underwent treatment after tumor growth at a median of 3.2 years after diagnosis (IQR 3.2-3.8), compared with 138 patients in the referent cohort at a median of 2.2 years after diagnosis (IQR 1.4-3.6). Treatment-free survival rates (95% CI, number still at risk) at 5 years after diagnosis for the 2 cohorts were 92% (86-98, 55) and 54% (49-61, 125), respectively (p < 0.001). Among the 105 patients with very small VS and class A, B, or C hearing at diagnosis, 3 progressed to class D. Comparatively, among the 225 patients in the referent cohort with class A, B, or C hearing at diagnosis, 70 progressed to class D at a median of 2.6 years after diagnosis (IQR 1.0-4.8). Rates of maintenance of class A, B, or C hearing (95% CI, number still at risk) at 5 years after diagnosis were 96% (92-100, 28) for patients with very small VS and 65% (57-73, 70) for the referent cohort (p < 0.001). CONCLUSIONS:The natural history of tumor growth and hearing for very small VS diverges favorably from the cumulative natural history data and provides a more appropriate benchmark to compare clinical outcomes of upfront surgery or radiosurgery for this population. At 5 years after diagnosis, 96% of very small VS maintained class A, B, or C hearing and only 8% received treatment for growth within this multicenter cohort. Cumulatively, these data substantiate initial wait-and-scan management via size threshold surveillance in this population. LEVEL OF EVIDENCE: 3:

OBJECTIVE:Communicating hydrocephalus may occur following stereotactic radiosurgery (SRS) for vestibular schwannomas (VSs), yet identifying individual patient risk factors associated with this post-SRS complication remains a challenge. This study examined predictors of nonobstructive ventricular enlargement and symptomatic communicating hydrocephalus following primary SRS treatment for VS via a single-center institutional cohort review and meta-analysis of the literature. METHODS:A retrospective single-institution cohort study and systematic literature review and meta-analysis examining post-SRS communicating hydrocephalus in VS was performed. RESULTS:The institutional cohort consisted of 634 patients who received primary SRS as treatment for VS. The cohort was 51.6% female, with a median age of 64 (range 18-89) years. Following SRS treatment, 364 patients (57.4%) experienced tumor shrinkage, 218 (34.4%) had no change in the size of their lesion, and 52 (8.2%) experienced tumor growth. Nonobstructive ventricular enlargement was observed in 23 patients (3.6%) following SRS treatment, of whom 9 (39.1%) remained asymptomatic and 14 (60.9%) required placement of a ventriculoperitoneal (VP) shunt, with a median time to shunt placement of 8 months. In the multivariate analysis, patients ≥ 65 years old (p = 0.038), SRS target volume ≥ 5 cm3 (p < 0.001), maximum SRS dose ≥ 26 Gy (p = 0.015), and tumor growth at the most recent follow-up (p = 0.002) were associated with an increased risk of post-SRS ventricular enlargement. Similarly, patients with older age (p = 0.049), increased SRS target volume (p = 0.002), and tumor growth (p = 0.016) were at an increased risk of symptomatic communicating hydrocephalus requiring VP shunt placement. Twenty-nine studies, including the cohort in this study, met inclusion criteria in the meta-analysis. Of the pooled 7825 patients, the overall incidence of hydrocephalus following SRS was 5%, and a subanalysis of 7081 patients demonstrated the incidence of symptomatic hydrocephalus requiring a VP shunt to be 4%. In this subanalysis, the overall shunting rate in patients who experienced post-SRS ventriculomegaly was 92%. Among individual studies in the literature, increased tumor size was most commonly found to be a statistically significant risk factor for post-SRS hydrocephalus. CONCLUSIONS:Approximately 5% of patients may experience nonobstructive ventricular enlargement following primary SRS treatment for VS. However, not all patients may be symptomatic and require shunting. Patients who are older (≥ 65 years), those with larger tumor volumes, and those with post-SRS tumor growth may be at increased risk of communicating hydrocephalus and may benefit from closer clinical monitoring.

OBJECTIVE:To examine microsurgical outcomes of medial sporadic vestibular schwannoma (VS), defined as a spherical tumor within the cerebellopontine angle (CPA) without tubular internal auditory canal (IAC) extension, compared with a referent cohort of "typical" VS with IAC extension. STUDY DESIGN:Historical matched cohort study. SETTING:Tertiary referral center. PATIENTS:Forty patients with medial sporadic VS who met the inclusion criteria were each matched to 3 referent patients by age, CPA tumor size, preoperative hearing class, and surgical approach. INTERVENTIONS:Microsurgical resection. MAIN OUTCOME MEASURES:Extent of resection, immediate and long-term postoperative facial nerve weakness (House-Brackmann grade >I), and long-term hearing preservation were compared between patients with medial VS and the referent cohort using conditional logistic regression. RESULTS:Medial VS and matched patients with IAC extension were not statistically significantly different in nongross total extent of resection (OR: 1.04, 95% CI: 0.47-2.31), immediate (OR: 0.82, 95% CI: 0.40-1.67) or long-term (OR: 0.59, 95% CI: 0.23-1.48) postoperative facial nerve weakness, or long-term nonserviceable hearing (OR: 0.84, 95% CI: 0.17-4.22). CONCLUSIONS:In this matched cohort study of medial VS, we found no statistically significant differences in the extent of resection, facial nerve function, or hearing preservation between tumors with and without IAC extension.

OBJECTIVE:Brain metastases significantly impact neurocognitive function and overall survival. Stereotactic radiosurgery (SRS) is a cornerstone of treatment for patients with limited metastases and expected survival beyond 3 months. Despite current guidelines, up to 20% of patients with brain metastases undergoing SRS have been reported to die within 90 days. This study retrospectively evaluated prognostic factors associated with 90-day survival after SRS, aiming to improve patient selection. METHODS:The authors retrospectively analyzed a cohort of 1546 patients who underwent Gamma Knife SRS for brain metastases at their institution between 2015 and 2023. One hundred seventy patients who survived less than 90 days after SRS were identified and case matched to 170 patients who survived over 90 days. Measured variables included patient demographic characteristics, tumor characteristics, treatment history, functional status, and control of the primary cancer. The authors modeled post-SRS 90-day survival using binomial and multivariate logistic regression. RESULTS:Multivariate analysis highlighted Karnofsky Performance Score (KPS) < 70 (OR 17.4, p < 0.001), prior whole-brain radiation (OR 6, p = 0.004), and focal neurological deficits (OR 3.02, p = 0.003) as significant predictors of poor survival, whereas CNS progression before SRS (OR 0.22, p < 0.001) and control of systemic cancer (OR 0.556, p = 0.002) were associated with survival < 90 days. The predictive model demonstrated acceptable performance with an area under the curve (AUC) of 0.85, accuracy of 80%, sensitivity of 87%, and specificity of 71%. CONCLUSIONS:Key predictors of 90-day survival after SRS for brain metastases include functional status (KPS), control of systemic cancer, CNS progression status, and focal neurological deficits. These findings are complementary factors that can assist in making decisions and SRS patient selection.

BACKGROUND:Cerebrospinal fluid (CSF) leak after retrosigmoid vestibular schwannoma resection remains a challenging complication. Historically, surgeons reopened the prior retrosigmoid incision for transmastoid repair because the safety of creating a separate postauricular incision was uncertain, with concerns regarding wound breakdown and infection. However, limited data support this practice, and a focused mastoid incision may offer improved access and patient tolerance. This study evaluated wound healing outcomes following transmastoid repair using a new postauricular incision for persistent CSF leak after retrosigmoid surgery in patients without serviceable hearing. METHODS:We retrospectively reviewed 27 patients who underwent transmastoid repair for persistent postoperative CSF leak after retrosigmoid craniotomy for vestibular schwannoma (2000-2025). Demographics, operative details, timing of leak diagnosis and repair, wound complications, readmissions, antibiotic use, and culture results were analyzed. RESULTS:Median age was 48 years (IQR 41-56); 67% were male, and mean BMI was 29.0 kg/m2. Mastoid obliteration was performed in 96%, with fat grafting in 93%. A new postauricular incision was used in all cases. Median time to leak diagnosis was 13 days (IQR 4-79), and median time to repair was 2 days (IQR 1-5). One patient (3.7%) developed a superficial wound abscess; no dehiscence or flap necrosis occurred. At median follow-up of 34 months (IQR 2.9-87.7), all wounds were healed. CSF leak recurred in two patients (7.4%) and three (11.1%) required reoperation. CONCLUSION:A separate postauricular incision for transmastoid CSF leak repair was not associated with increased wound morbidity. Durable wound healing was achieved in all patients, with 93% legal control, supporting this anatomy-driven approach. LEVEL OF EVIDENCE: 4:

Abstract Vestibular schwannomas are woven into the historical foundation and contemporary practice of skull base surgery. These tumors are relatively common compared to other skull base lesions, and while diagnosis has become relatively streamlined with the widespread availability of high-resolution magnetic resonance imaging and the use of audiological screening criteria, management remains relatively nuanced and increasingly funneled into tertiary care settings with multidisciplinary care teams.

OBJECTIVE:Wait-and-scan surveillance is now commonly employed for initial management of small- and medium-sized vestibular schwannomas. Although small differences in tumor size are unlikely to impact outcomes significantly, treatment with either radiosurgery or microsurgery is usually recommended following radiological detection of tumor growth. The objective of the current study was to identify potential inflection points in vestibular schwannoma tumor size, where the risks of treatment with single-fraction stereotactic radiosurgery (SRS) accelerate to inform timing of intervention. METHODS:Adult (≥ 18 years old) patients with sporadic vestibular schwannoma who underwent SRS from 2000 through 2022 were included. RESULTS:A total of 749 patients with a median age at SRS of 62 years were studied, the majority (n = 566 [76%]) of whom had tumors extending into the cerebellopontine angle (CPA) at SRS. The optimal tumor size cut point to predict SRS failure and need for salvage treatment was 4 mm or more of CPA extension (c-index 0.59, HR 3.60, p = 0.01). The optimal tumor size cut point to predict the outcome of facial nerve paresis was 13 mm or more of CPA extension, resulting in a c-index of 0.63 (HR 2.88, p = 0.01). Among patients with at least 3 months of surveillance before SRS, those with a tumor growth rate ≥ 2.5 mm/year were more likely to undergo salvage treatment than those with a growth rate < 2.5 mm/year, although this difference did not achieve statistical significance (HR 1.82, p = 0.18). CONCLUSIONS:The risk of SRS failure requiring salvage treatment and the risk of post-SRS facial nerve paralysis increase at sizes of approximately 4 and 13 mm extension into the CPA, respectively, providing a size threshold anchor to help guide treatment decision-making regarding timing of SRS. Furthermore, rapid tumor growth during the initial wait-and-scan period may be associated with an increased risk of radiosurgical failure, which may influence choice of treatment.

OBJECTIVE:The objective of this study was to describe the long-term efficacy of single-fraction stereotactic radiosurgery (SRS) for the primary treatment of sporadic vestibular schwannoma. METHODS:Adult (≥ 18 years of age) patients with sporadic vestibular schwannoma who underwent SRS from 2000 through 2022 were included. RESULTS:A total of 749 patients met inclusion criteria, the majority (n = 566, 76%) of whom had tumors extending into the cerebellopontine angle at SRS. The median patient age at SRS was 62 years, half (50%) of the patients were women, and 744 (99%) exhibited House-Brackmann grade I facial nerve function at SRS. A total of 42 patients experienced radiosurgical failure and underwent salvage treatment; the median duration of follow-up for the patients who did not undergo salvage treatment was 7.0 years. Overall tumor control rates (95% CI, number still at risk) at 1, 3, 5, 10, and 15 years after SRS were 100% (100%-100%, 718), 98% (97%-99%, 589), 96% (94%-97%, 464), 92% (90%-95%, 258), and 91% (89%-94%, 125), respectively. Patient age (hazard ratio [HR] for a 10-year increase of 0.92, 95% CI 0.71-1.19; p = 0.5), presence of a macrocystic tumor (HR 0.59, 95% CI 0.14-2.46; p = 0.5), and treated tumor volume (HR for a 1-cm3 increase of 1.02, 95% CI 0.88-1.18; p = 0.8) were not significantly associated with the risk of salvage. Three distinct post-SRS tumor behavior patterns were observed, with 13% of patients demonstrating tumor pseudoprogression, all but 4 of whom demonstrated pseudoprogression by year 5 post-SRS. CONCLUSIONS:SRS demonstrates durable tumor control through 15 years of follow-up in most patients (91%); however, a minority are found to still experience SRS failure even beyond 10 years of surveillance. Although occurring in only a minority of patients, tumor pseudoprogression can be evident out to 5 years or longer post-SRS.

Vestibular schwannomas are the most common tumor of the cerebellopontine angle, estimated to occur in about 1 per 500 people. They most commonly present with unilateral hearing loss. We review the epidemiology and present a comprehensive review of the preoperative work-up, including formal assessment of symptoms and imaging evaluation. We present practices for supporting patients with prehabilitation techniques and symptom management. We then discuss available treatment options and outline the evidence for each before detailing an approach to counseling the patient.

In this video, the authors present the microsurgical treatment of a superior petrosal dural arteriovenous fistula (dAVF) associated with a symptomatic hemorrhagic brainstem cavernous malformation in a 38-year-old male. The patient underwent a retrosigmoid craniotomy for cavernoma evacuation and fistula disconnection. Intraoperative indocyanine green angiography revealed cortical venous reflux not evident on catheter angiography, prompting reclassification to a higher-grade fistula. Postoperatively, the patient returned to neurological baseline, and follow-up imaging confirmed complete fistula obliteration, cavernoma resection, and new appearance of a developmental venous anomaly (DVA). This case highlights the dynamic nature of dAVF venous drainage and illustrates the rare co-occurrence of dAVF, DVA, and brainstem cavernoma. The video can be found here: https://stream.cadmore.media/r10.3171/2025.7.FOCVID2553.