Carlson, Matthew L.

Abstract Background Evaluation of middle ear prostheses requires high-resolution imaging to assess position and structural integrity. Purpose To assess the diagnostic performance of photon-counting-detector (PCD)-CT for middle ear prosthesis imaging in cadaveric specimens. Materials and Methods Nine different middle ear prostheses were implanted in five fresh-frozen whole-head specimens, both in correct anatomic position and displaced to mimic malposition. Specimens were scanned on PCD-CT (NAEOTOM Alpha, Siemens) and energy-integrating-detector (EID)-CT (SOMATOM Force, Siemens), reconstructed at 0.2mm and 0.4mm, respectively. Eighteen cases (9 prostheses, 2 positions) per scanner were evaluated by two neuroradiologists (36 readings), blinded to scanner and position, who scored prosthesis position, reader confidence, and overall image quality. Agreement with the reference standard and between readers was compared. Results PCD-CT showed higher diagnostic confidence compared with EID-CT, while accuracy and inter-reader agreement did not demonstrate significant differences between scanners. Correct readings, PCD-CT versus EID-CT: lateral contact, 31/36 (86.1%; 95% CI: 58.3%-94.4%) vs. 29/36 (80.6%; 55.6%-91.7%), p = 0.500; medial contact, 30/36 (83.3%; 55.6%-94.4%) vs. 26/36 (72.2%; 50.0%-83.3%), p = 0.250. PCD-CT identified all cases of complete contact loss (score 3), while EID-CT missed one reading per contact. Inter-reader agreement may be higher with PCD-CT vs EID-CT (lateral: κw: 0.804 [0.578-0.941] vs. 0.571 [0.302-0.778], p = 0.250; medial: 0.684 [0.191-0.934] vs. 0.481 [0.024-0.835], p = 0.250). Reader confidence was significantly higher with PCD-CT; mean paired differences for Readers 1 and 2 were 9.4 (1.8-17.1; Holm-adjusted p = 0.019) and 23.1 points (13.4-32.7; p < 0.001) for lateral contact, and 16.4 (10.0-22.8; p < 0.001) and 17.8 points (6.8-28.8; p = 0.007) for medial contact. Readers preferred PCD-CT image quality in 16/18 (88.9%; 65.3%-98.6%) and 17/18 cases (94.4%; 72.7%-99.9%), respectively. Conclusion PCD-CT was associated with significantly higher reader confidence and preferred image quality, without significant differences in diagnostic accuracy or inter-reader agreement. These findings suggest PCD-CT is a promising modality for postoperative middle ear evaluations that warrants further investigations.

Purpose of review Photon-counting detector computed tomography (PCD-CT) represents a major technological advancement in computed tomography, offering improved spatial resolution, reduced image noise, and increased dose efficiency compared with conventional energy-integrating detector CT (EID-CT). Because many clinically relevant structures within the temporal bone are submillimeter in size, the temporal bone represents an ideal region for determining whether these technical improvements translate into meaningful clinical benefits. This review evaluates the emerging literature on PCD-CT in temporal bone imaging and examines whether higher spatial resolution meaningfully impacts clinical decision-making. Recent findings Recent studies demonstrate improved visualization of middle ear anatomy, ossicular prostheses, cochlear implant electrode arrays, and superior semicircular canal dehiscence with PCD-CT compared with conventional CT. Improved spatial resolution and reduced metal artifact have been shown to enhance assessment of prosthesis positioning, cochlear duct measurements, and differentiation of true versus near semicircular canal dehiscence. However, given the recent availability of PCD-CT, most studies to date have focused on cadaveric studies, phantom studies, or patient studies evaluating image quality rather than diagnostic accuracy or clinical outcomes. Summary PCD-CT provides substantially improved visualization of submillimeter temporal bone structures and may improve diagnostic confidence in select clinical scenarios. Nevertheless, evidence demonstrating improved clinical outcomes remains limited, and further clinical studies are needed to define the role of PCD-CT in routine temporal bone imaging.

Objective: To describe cochlear implant outcomes in a patient with bilateral rapidly progressive hearing loss secondary to Kelch-like protein–11 (KLHL11) IgG rhombencephalitis. Patient: A 26-year-old male presenting to neurotology clinic at a tertiary care center for evaluation of bilateral rapidly progressive sensorineural hearing loss, unresponsive to systemic corticosteroid therapy. Interventions: Bilateral simultaneous cochlear implantation. Main Outcome Measures: Postimplant speech testing (CNC word, AzBio sentence scoring), and changes to hearing function with fluctuations in systemic disease symptomatology. Results: Preoperative testing demonstrated poor speech perception (bilateral AzBio sentence in quiet: 43%, right-sided CNCw score: 38%, and left-sided CNCw score: 0%). Despite systemic disease progression of KLHL11-IgG rhombencephalitis, including worsening cerebellar ataxia and dysarthria, cochlear implant performance did not decrease at the time of last follow-up. At 1-year, binaural and monaural speech testing were both significantly improved compared with the 1-month testing (bilateral AzBio sentence in quiet: 91%, right-sided CNCw score: 70%, and left-sided CNCw score: 32%). Conclusions: Cochlear implantation may offer meaningful auditory rehabilitation in patients with KLHL11-IgG associated rhombencephalitis with relative auditory nerve sparing, despite ongoing disease progression. Further studies are required to evaluate the durability and generalizability of cochlear implantation across the spectrum of disease-related hearing loss.

Objective: Characterize pathogenic variants, rates of mosaicism, genetic testing yield, and disease severity among patients with NF2-related schwannomatosis dichotomized by diagnosis before or after the age of 30. Study design: Retrospective analysis. Setting: Tertiary referral center multidisciplinary NF2 clinic from 2021 to 2024. Patients: Patients with NF2-related schwannomatosis. Intervention: Next-generation sequencing. Main outcome measure: Rates of mosaicism, genetic testing rates and yield, and overall disease severity by tumor burden. Results: From 2021 to 2024, there were 32 patients ≥30 years of age and 39 patients diagnosed at younger ages. Patients diagnosed ≥30 years exhibited decreased likelihood of receiving genetic testing (53% vs. 85%; P =0.009) and decreased genetic yield (defined as identification of a pathogenic genetic variant in those undergoing testing; 65% vs. 85%; P =0.20). Both age groups demonstrated similar rates of pathogenic variant type with loss-of-function being the predominant variant detected in 73% vs. 67%, for ≥30 vs. <30 years of age; P =0.90. Those ≥30 years harbored fewer number of average anatomic regions involved by tumor (2.3 vs. 3.4; P <0.001) and decreased total number of tumors (7 vs. 12; P <0.001). Conclusions: Patients diagnosed with NF2-related schwannomatosis at age ≥30 years exhibited reduced disease severity compared with those diagnosed at a younger age despite harboring similar distributions of genetic pathogenic variants inclusive of loss-of-function pathogenic variants. These observations emphasize the importance of considering patient age in addition to genetic testing for diagnostic framing tailored to patients’ biology and clinical context to optimize care in the setting of NF2-related schwannomatosis.

ABSTRACT 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/m 2 . 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

Objective: To synthesize the available evidence on medical therapies investigated for the management of NF2-related vestibular schwannomas (VS). Study design: Systematic review. Setting: Not applicable. Patients: NF2-related VS patients. Interventions: Systemic medical therapies. Main outcome measures: Tumor control and hearing outcomes. Results: Thirty studies met inclusion criteria: 18 investigated bevacizumab, 5 mTOR inhibitors, 5 tyrosine kinase inhibitors (TKIs), and 2 the vascular endothelial growth factor receptor (VEGFR) vaccine. Bevacizumab demonstrated the most consistent activity, with hearing improvement in up to 61% of patients, stable hearing in up to 84%, and tumor response in up to 60% (Level 4 evidence). Outcomes for mTOR inhibitors were variable, with 1 study stopped for futility, while others reported up to 100% hearing and tumor stability (Level 4 evidence). Five different TKIs showed hearing improvement rates ranging from 17 to 60% and tumor responses of 10 to 23.5% (Level 4 evidence). The VEGFR vaccine appeared safe and immunologically active, with radiologic and hearing improvement in one-third of patients (Level 4 evidence). Conclusions: Bevacizumab remains the most studied and clinically active systemic therapy for NF2-related VS, although evidence is largely nonrandomized. Other systemic therapies have demonstrated variable results in terms of hearing outcomes or tumor control. High-quality prospective and randomized controlled trials are needed to clarify efficacy, durability, and comparative effectiveness.

Objective: To evaluate magnetic resonance (MR) imaging artifact and image distortion associated with the Oticon Medical Sentio Ti bone conduction implant (BCI) and identify optimized imaging techniques. Study design: Cadaveric study. Intervention: One cadaveric head specimen was unilaterally implanted with Sentio Ti BCI according to the manufacturer's instructions. Main outcome measures: Imaging was performed with a Siemens 1.5 Tesla MR machine on XA60 software before and after implantation. Imaging was performed with both standard and metal mitigation techniques. Image scoring (diagnostic vs. nondiagnostic) and qualitative assessment of anatomic subsites were performed by 2 experienced neuroradiologists. Results: Image distortion and artifact were noted in all postimplant sequences. For all sequences, imaging of the ipsilateral middle ear, mastoid, and internal auditory canal (IAC) was nondiagnostic. The axial T1 turbo spin echo high bandwidth sequence had the best artifact reduction; however, the ipsilateral temporal bone remained nondiagnostic. Notably, nonecho planar diffusion-weighted imaging (non-EPI DWI) was nondiagnostic for both the ipsilateral temporal bone and the contralateral IAC and middle ear. Conclusions: After implantation of the Sentio Ti BCI, imaging of the ipsilateral temporal bone is rendered nondiagnostic on all MR sequences due to artifact despite the use of metal mitigation techniques. Importantly, the non-EPI DWI HASTE sequence, which is used for cholesteatoma surveillance, is nondiagnostic for all ipsilateral and most contralateral temporal bone subsites, making cholesteatoma surveillance challenging with an implant in place. This finding is critical for clinical decision-making, as rehabilitation of conductive hearing loss in the setting of chronic otitis media is among the most common indications for use of a BCI.

ABSTRACT 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: 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.