Driscoll, Colin L. W.

Abstract We describe a case of a child with macrolide-resistant Mycobacterium abscessus who initially had clinical improvement on a dual β-lactam regimen but continued to have positive cultures. Suitable phages active against the bacterial strain were identified, administered both systemically and directly to the ear, and were associated with microbiological remission.

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

Abstract 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. 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. Investigational period: 2022 to 2025. Survey instruments distributed at the 2023 American Neurotology Society (ANS) Fall Meeting. ANS, American Academy of Otolaryngology (AAO-HNSF), and the North American Skull Base Society (NASBS) representatives. Usage rate for CPT code sets (percentage of responders). 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. 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.

Objective: Auditory nerve monitoring through electrically evoked compound action potentials (eCAP) can be used to assess cochlear neural integrity during vestibular schwannoma (VS) resection. Herein, we report on 5 cochlear implant (CI) patients who underwent VS resection with present eCAP responses both intraoperatively and postoperatively. Patients either did not perceive any sound through their CI or rapidly adapted to electrical stimulation, suggesting that the presence of eCAP does not guarantee auditory nerve function in patients with VS resection. Patients: Five patients who underwent simultaneous VS translabyrinthine resection and cochlear implantation. Interventions: Simultaneous cochlear implantation and translabyrinthine microsurgical VS resection. Main outcome measure: Electrically evoked compound action potential. Results: All patients had eCAP responses present during their VS resection and for at least 50 days post-surgery. Three of the 5 patients did not perceive any sound with their cochlear implant. This shows that the presence of an eCAP alone does not guarantee a functional auditory nerve or auditory perception. The other 2 patients could hear non-speech sounds, but these sounds quickly became inaudible, indicating that their auditory nerve lacked the ability to integrate the electrical stimulus over time. Conclusions: The presence of an eCAP response does not guarantee auditory sensation through a CI. Although eCAP measurements provide insight into the function of the distal end of the nerve, it does not ascertain integrity or function of the larger auditory nerve pathway. Therefore, eCAPs should not be used in isolation to monitor auditory nerve function during VS resection.

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-cm 3 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.

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.