Retrosigmoid Approach for Sporadic Vestibular Schwannoma: Patient Selection, Technical Pearls, and Hearing Results.

The retrosigmoid corridor provides the most broadly applied approach for resection of sporadic vestibular schwannoma. It may be utilized for any size tumor and for patients with intact hearing with the intention of hearing preservation. For larger tumors, the skull base surgeon must weigh the benefits the retrosigmoid approach against those of the translabyrinthine route. For smaller tumors where hearing preservation is a goal, the retrosigmoid approach is contrasted to the middle fossa route. Hearing preservation is most likely for patients with small and medially located intracanalicular tumors with minimal extension into the cerebellopontine angle, and excellent preoperative hearing.

Twelve-Month Outcomes of Simultaneous Translabyrinthine Resection and Cochlear Implantation.

OBJECTIVE: Audiometric outcomes at 12 months following simultaneous translabyrinthine (TL) resection of vestibular schwannoma (VS) and cochlear implantation (CI). STUDY DESIGN: Prospective cohort study. SETTING: Tertiary referral center. METHODS: Adult patients undergoing TL resection of sporadic, unilateral VS ≤ 2 cm were prospectively enrolled. Preoperative testing included binaural AZBio in noise and quiet and unilateral Consonant-Nucleus-Consonant (CNC). Tinnitus Handicap Index (THI) and Speech, Spatial, and Qualities of Hearing (SSQ) questionnaires were also completed. Patients underwent TL resection with simultaneous CI. The preoperative test battery was repeated at 1, 3, 6, and 12 months after activation. Statistical analysis was performed to characterize short-term outcomes (preoperative to 3 months), longer-term outcomes (3-12 months), and overall changes during the preoperative to 12-month period. RESULTS: AZBio, CNC, and THI improved at 3 months with no significant changes thereafter and showed durable improvement at 12 months compared to preoperative testing. While SSQ did not improve at 12 months, a subset of patients showed either recovery or improvement of SSQ-spatial subscores. Patients with cerebellopontine angle tumors had poorer performance, although the impact of tumor size and location could not be deduced based on the small sample size. CONCLUSION: Patients undergoing simultaneous CI and TL resection of VS had durable improvements in speech perception and tinnitus severity 12 months following surgery. Subjective improvements in localization were not observed. Additional studies are needed to determine which VS patients are optimal candidates for CI.

Cost-Effectiveness of Routine Type and Screens in Select Endonasal Skull Base Surgeries.

Objective The study aimed to evaluate the cost-effectiveness of obtaining preoperative type and screens (T/S) for common endonasal skull base procedures, and determine patient and hospital factors associated with receiving blood transfusions. Study Design Retrospective database analysis of the 2006 to 2015 National (nationwide) Inpatient Sample and cost-effectiveness analysis. Main Outcome Measures Multivariate regression analysis was used to identify factors associated with transfusions. A cost-effectiveness analysis was then performed to determine the incremental cost-effectiveness ratio (ICER) of obtaining preoperative T/S to prevent an emergency-release transfusion (ERT), with a willingness-to-pay threshold of $1,500. Results A total of 93,105 cases were identified with an overall transfusion rate of 1.89%. On multivariate modeling, statistically significant factors associated with transfusion included nonelective admission (odds ratio [OR]: 2.32; 95% confidence interval [CI]: 1.78-3.02), anemia (OR: 4.42; 95% CI: 3.35-5.83), coagulopathy (OR: 4.72; 95% CI: 2.94-7.57), diabetes (OR: 1.45; 95% CI: 1.14-1.84), liver disease (OR: 2.37; 95% CI: 1.27-4.43), pulmonary circulation disorders (OR: 3.28; 95% CI: 1.71-6.29), and metastatic cancer (OR: 5.85; 95% CI: 2.63-13.0; p < 0.01 for all). The ICER of preoperative T/S was $3,576 per ERT prevented. One-way sensitivity analysis demonstrated that the risk of transfusion should exceed 4.12% to justify preoperative T/S. Conclusion Routine preoperative T/S does not represent a cost-effective practice for these surgeries using nationally representative data. A selective T/S policy for high-risk patients may reduce costs.

Early Outcomes of Simultaneous Translabyrinthine Resection and Cochlear Implantation.

OBJECTIVES/HYPOTHESIS: Hearing rehabilitation after translabyrinthine resection of a vestibular schwannoma (VS) has largely been based on the transfer of acoustic stimulus to the contralateral ear, typically through a contralateral routing of signal hearing aid or bone-anchored hearing aid (BAHA). Cochlear implant, either as a subsequent surgery or simultaneously, has become a more common treatment option; however, there is still relatively limited data available on its success. The purpose of this study is to evaluate the early outcomes of simultaneous cochlear implantation in patients with sporadic VS undergoing translabyrinthine resection. STUDY DESIGN: Prospective, nonrandomized study. METHODS: A prospective study of nonrandomized patients was completed at a tertiary care neurotology center. Audiologic outcomes, primarily based on AzBIO in quiet and background noise, as well as consonant-nucleus-consonant (CNC) testing of the affected ears were utilized. Tinnitus, dizziness, and spatial hearing questionnaries were also completed. Audiologic outcomes and questionnaires were compared between the pre- and postoperative groups. RESULTS: Ten patients were included in the study with 3 month follow-up data. There was statistically significant improvement in AzBO with +10 and +5 signal to noise ratio and in quiet, as well as in CNC testing (P < .05). There was a significant improvement in Tinnitus Handicap Inventory between the two groups. CONCLUSIONS: Simultaneous cochlear implantation is a viable treatment for hearing loss after translabyrinthine approach to VS. These patients have improved hearing in background noise and tinnitus compared to their preoperative state. Further prognostic data are required to determine which patients are the best candidates. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:E2312-E2317, 2021.

Hydroxyapatite cement cranioplasty in the setting of simultaneous translabyrinthine resection of cerebellopontine angle tumors and cochlear implantation.

Cochlear implantation (CI) has become an option for the treatment of hearing loss after translabyrinthine resection of vestibular schwannomas. The surgical video presents the case of a 67-year-old male who had translabyrinthine resection of vestibular schwannoma with simultaneous CI and closure with a hydroxyapatite (HA) cement cranioplasty. HA cement cranioplasty can be utilized in place of abdominal fat graft for the closure of translabyrinthine approaches with similar efficacy and complication profile. To the authors' knowledge, this is the first reported case of a simultaneous CI and translabyrinthine resection of vestibular schwannoma with HA cement cranioplasty. The video can be found here: https://stream.cadmore.media/r10.3171/2021.7.FOCVID211.

Natural History of Facial Weakness Following Surgery of the Cerebellopontine Angle: A Tertiary Care Cohort.

OBJECTIVE: Facial function is a key outcome in surgery of the cerebellopontine angle (CPA). This study describes the natural history of facial weakness after CPA surgery. STUDY DESIGN AND SETTING: Retrospective study of two tertiary centers. PATIENTS AND INTERVENTION: Patients undergoing surgery for CPA tumors from 2003 to 2017 with preoperatively normal facial function and without subsequent surgical or adjuvant therapy. MAIN OUTCOME MEASURE: Serial facial nerve examinations using the House-Brackmann (HB) scale. RESULTS: Of 301 patients examined, 149 (49.5%) had facial weakness postoperatively and 74.5% of these occurred within 24 hours. Of patients with HB-1 function within 24 hours after surgery, 95.3% had HB-1 function and 100% had HB-3 or better function at last follow-up. Of patients with HB-4 or worse function within 24 hours after surgery, 22.6% ultimately achieved HB-1 function and 83.9% ultimately achieved HB-3 or better function. By 180 days postoperatively, 83.7% of patients' facial function had stabilized. At last follow-up, 3.0% of patients had facial function poorer than HB-3, which was associated with subtotal resections (12.9% vs. 4.4% for near total and 0.6% for gross total resections, p = 0.002), aspirin use (10.6% vs. 1.6%, p = 0.001), larger tumors (p < 0.0005), longer surgery (p < 0.002), and immediate versus delayed postoperative facial weakness (p = 0.002). CONCLUSIONS: Facial function over time after CPA surgery is presented. While facial function immediately after surgery correlates with future function, delayed weakness or improvement is common. These data inform patient counseling both preceding and following surgery.

Impact of cochlear modiolus dose on hearing preservation following stereotactic radiosurgery for non-vestibular schwannoma neoplasms of the lateral skull base: a cohort study.

OBJECTIVE: Radiation dose to the cochlea has been proposed as a key prognostic factor in hearing preservation following stereotactic radiosurgery (SRS) for vestibular schwannoma (VS). However, understanding of the predictive value of cochlear dose on hearing outcomes following SRS for patients with non-VS tumors of the lateral skull base (LSB) is incomplete. The authors investigated rates of hearing loss following high-dose SRS in patients with LSB non-VS lesions compared with patients with VS. METHODS: Patients with LSB meningioma or jugular paraganglioma and serviceable pretreatment hearing who underwent SRS treatment during 2007-2016 and received a modiolus dose > 5 Gy were included in a retrospective cohort study, along with a similarly identified control group of consecutive patients with sporadic VS. RESULTS: Sixteen patients with non-VS tumors and a control group of 43 patients with VS met study criteria. Serviceable hearing, defined as American Academy of Otololaryngology-Head and Neck Surgery class A/B, was maintained in 13 non-VS versus 23 VS patients (81% vs 56%, p = 0.07). All 3 instances of hearing loss in non-VS patients were observed in cerebellopontine angle (CPA) meningiomas. Non-VS with preserved hearing had a median modiolus dose of 6.9 Gy (range 5.7-19.2 Gy), versus 7.4 Gy (range 5.4-7.6 Gy) in those patients with post-SRS hearing loss (p = 0.53). Sporadic VS patients received an overall median modiolus point-dose of 6.8 Gy (range 5.4-11.7 Gy). CONCLUSIONS: The modiolus dose threshold of 5 Gy does not predict hearing loss in patients with non-VS tumors undergoing SRS, suggesting that dosimetric parameters derived from VS may not be applicable to this population. Differential rates of hearing loss appear to vary by pathology, with paragangliomas and petroclival meningiomas demonstrating decreased risk of hearing loss compared to CPA meningiomas that may directly compress the cochlear nerve similarly to VS.

Anterior Extension of Tumor is as Important as Tumor Size to Facial Nerve Outcome and Extent of Resection for Vestibular Schwannomas.

Objectives We examined vestibular schwannoma tumor dimension and direction of growth to determine whether these correlate with facial nerve outcome as well as extent of resection (EOR). Design Retrospective review of prospectively maintained databases. Participants 206 patients were a part of this study. Main Outcome Measures Tumor dimensions were measured using preoperative magnetic resonance imaging, and a series of ratios were then calculated to further characterize tumor dimension. Regression analyses were performed to investigate correlation with facial nerve outcome and EOR. Results Patients with tumor extending >1.5 cm anterior to the internal auditory canal (IAC) (AB measurement) were three times more likely to have postoperative House-Brackman grades of 3 or worse. We also found that an EB/BF ratio (representing elongated growth parallel to the IAC axis) ≥1.1 was associated with half the risk of poor facial nerve outcome. Tumors with anterior-posterior diameter (AC measurement) >1.9 cm were five times less likely to undergo gross total resection (GTR). Furthermore, an increased degree of tumor extension into the IAC (DE measurement >2.4 cm) or an increased amount of brainstem compression (EB measurement >1.1 cm) were each associated with a nearly 3-fold decrease in the likelihood of GTR. Conclusion Our study demonstrates that anterior extent of the tumor is as important as tumor size to facial nerve outcome and degree of resection for vestibular schwannomas.

Pituitary and skull-base lesions and the litigious patient.

BACKGROUND: The objective of this research was to evaluate litigation relating to the diagnosis and management of pituitary and ventral skull base lesions and delineate allegations involved in the decision to pursue medicolegal proceedings. METHODS: Publically available federal and court records were accessed via the Westlaw Next database. Jury verdict and settlement reports relevant to pituitary and anterior skull-base lesions were accessed, and litigation was reviewed for alleged injuries, defendant specialty, patient demographics, and other factors raised in proceedings. RESULTS: Of 75 cases included, 50.7% were resolved in the defendant's favor. The most frequent physician specialties cited as defendants included primary care (20%), neurosurgery (17%), and radiology (16%), while otolaryngologists were defendants in only 5% of cases. Fifty-two (69%) did not involve surgical intervention; the most common allegations in these proceedings were misdiagnosis, permanent injury (19%), requiring additional procedures as a result of misdiagnosis (17%), permanent endocrine dysfunction (14%), and visual sequelae (12%). Among surgical cases, the most common allegations raised included permanent injury (17%), postoperative complications (14%), intraoperative complications (13%), and death (10%). Among cases resolved with payment, there was no statistical difference in payment between surgical cases ($5.7M) and nonsurgical cases ($4.8M). CONCLUSION: Misdiagnosis of endocrinopathy, failure to appropriately workup patients presenting with neurologic complaints, and radiologic misdiagnosis play important roles in the pursuit of litigation in nonsurgical cases. Sustaining permanent sequelae including endocrine and visual injury play an important role in surgical cases. Postoperative management appears to play just as important a role in the decision to pursue litigation as intraoperative considerations.

Long-term risk of recurrence and regrowth after gross-total and subtotal resection of sporadic vestibular schwannoma.

OBJECTIVE The management of vestibular schwannoma (VS) remains controversial. One commonly cited advantage of microsurgery over other treatment modalities is that tumor removal provides the greatest chance of long-term cure. However, there are very few publications with long-term follow-up to support this assertion. The purpose of the current study is to report the very long-term risk of recurrence among a large historical cohort of patients who underwent microsurgical resection. METHODS The authors retrospectively reviewed the medical records of patients who had undergone primary microsurgical resection of unilateral VS via a retrosigmoid approach performed by a single neurosurgeon-neurotologist team between January 1980 and December 1999. Complete tumor removal was designated gross-total resection (GTR), and anything less than complete removal was designated subtotal resection (STR). The primary end point was radiological recurrence-free survival. Time-to-event analyses were performed to identify factors associated with recurrence. RESULTS Four hundred fourteen patients met the study inclusion criteria and were analyzed. Overall, 67 patients experienced recurrence at a median of 6.9 years following resection (IQR 3.9-12.1, range 1.2-22.5 years). Estimated recurrence-free survival rates at 5, 10, 15, and 20 years following resection were 93% (95% CI 91-96, 248 patients still at risk), 78% (72-85, 88), 68% (60-77, 47), and 51% (41-64, 22), respectively. The strongest predictor of recurrence was extent of resection, with patients who underwent STR having a nearly 11-fold greater risk of recurrence than the patients treated with GTR (HR 10.55, p < 0.001). Among the 18 patients treated with STR, 15 experienced recurrence at a median of 2.7 years following resection (IQR 1.9-8.9, range 1.2-18.7). Estimated recurrence-free survival rates at 5, 10, 15, and 20 years following GTR were 96% (95% CI 93-98, 241 patients still at risk), 82% (77-89, 86), 73% (65-81, 46), and 56% (45-70, 22), respectively. Estimated recurrence-free survival rates at 5, 10, and 15 years following STR were 47% (95% CI 28-78, 7 patients still at risk), 17% (5-55, 2), and 8% (1-52, 1), respectively. CONCLUSIONS Long-term surveillance is required following microsurgical resection of VS even after GTR. Subtotal resection alone should not be considered a definitive long-term cure. These data emphasize the importance of long-term follow-up when reporting tumor control outcomes for VS.

The effect of diabetes mellitus on 30-day outcomes following single-level open lumbar microdiscectomy: an aged-matched case-control study.

BACKGROUND: Diabetes mellitus (DM) is a known risk factor for post-surgical complications. However, few reports specifically study lumbar spine surgical outcomes in diabetics. The purpose of this study was to assess 30-day outcomes in patients with DM undergoing single-level open lumbar microdiscectomy (oLMD). METHODS: A retrospective case control study on patients with DM undergoing between 2001 and 2012. Patients who underwent a minimally invasive approach, repeat discectomy, or multilevel surgery were excluded. One hundred and twenty-six patients were age-matched with 126 non-diabetic controls. Outcomes assessed included length of stay (LOS), postoperative urinary retention (UR), total morbidity, infection, postoperative radiculitis, 30-day re-admissions and emergency department visits, and pain status at discharge and at 30 days. Categorical variables were evaluated with Pearson's χ2 tests. Student's t-tests were used to evaluate continuous variables. Univariate logistic regression was used to evaluate strength of association of DM with outcome variables. RESULTS: Mean LOS was significantly higher in diabetic patients (1.9 vs. 1.4 days, P<0.0001). DM was associated with increased morbidity (P=0.009, OR=3.3, CI: 1.3-9.5) and UR (P<0.0001, OR=8.2, CI: 3.4-24.8). No differences were found in 30-day readmission rates or emergency department visits, pain status at discharge and at 30 days, or postoperative radiculitis. CONCLUSIONS: Overall, short-term outcomes are worse in patients with DM. Following single-level oLMD, DM is associated with longer hospital stays, UR, and increased morbidity. These short term outcomes consequently lead to an overall increase in hospital costs.

Lower airway disease and pituitary surgery: Is there an association with postoperative cerebrospinal fluid leak?

OBJECTIVES/HYPOTHESIS: To explore the relationship between lower airway disease and postoperative cerebrospinal fluid (CSF) rhinorrhea among patients undergoing pituitary surgery STUDY DESIGN: Retrospective review. METHODS: A retrospective review of the Healthcare Cost and Utilization Project's 2013 National Inpatient Sample was conducted to characterize the hospital stay and surgical outcomes of patients undergoing pituitary surgery. Patients with lower airway disease (including chronic obstructive pulmonary disease and asthma) were compared to a disease-free population identifying demographics and complications over-represented in the lower airway group. RESULTS: The majority of hypophysectomies (92.1%) were performed via a transsphenoidal approach. Among transsphenoidal patients, individuals with asthma (92.8% of the lower airway disease cohort) harbored a greater postoperative CSF leak rate (4.7% vs. 2.7%, P = .022), and were more likely to develop postoperative diabetes insipidus (6.2% vs. 4.1%, P = .024) and neurological complications (13.0% vs. 9.6%, P = .010) when compared to a lower airway disease-free cohort. Patients with CSF rhinorrhea had longer lengths of stay (7.8 days vs. 4.5 days, P < .001) and higher discharge costs ($148,309 vs. $76,246, P < .001). A binary logistic regression model identified having asthma (P = .042), being female (P = .011), and having gastroesophageal reflux disease (P = .006) as independent predictors of postoperative CSF rhinorrhea. CONCLUSIONS: Several patient comorbidities including asthma are associated with a greater risk of postoperative CSF rhinorrhea. Perioperative lower airway assessment and disease control may potentially decrease one's risk of this complication, although further inquiry is urgently needed to identify optimal preventive strategies. LEVEL OF EVIDENCE: 2c. Laryngoscope, 127:1543-1550, 2017.

Pretreatment growth rate as a predictor of tumor control following Gamma Knife radiosurgery for sporadic vestibular schwannoma.

OBJECTIVE Over the last 30 years, stereotactic radiosurgery (SRS) has become an established noninvasive treatment alternative for small- to medium-sized vestibular schwannoma (VS). This study aims to further define long-term SRS tumor control in patients with documented pretreatment tumor growth for whom conservative observation failed. METHODS A prospective clinical database was queried, and patients with sporadic VS who elected initial observation and subsequently underwent SRS after documented tumor growth between 2004 and 2014 were identified. Posttreatment tumor growth or shrinkage was determined by a ≥ 2-mm increase or decrease in maximum linear dimension, respectively. RESULTS Sixty-eight patients met study inclusion criteria. The median pre- and posttreatment observation periods were 16 and 43.5 months, respectively. The median dose to the tumor margin was 13 Gy (range 12-14 Gy), and the median maximum dose was 26 Gy (range 24-28 Gy). At the time of treatment, 59 tumors exhibited extracanalicular (EC) extension, and 9 were intracanalicular (IC). Of the 59 EC VSs, 50 (85%) remained stable or decreased in size following treatment, and 9 (15%) enlarged by > 2 mm. Among EC tumors, the median pretreatment tumor growth rate was 2.08 mm/year for tumors that decreased or were stable, compared with 3.26 mm/year for tumors that grew following SRS (p = 0.009). Patients who demonstrated a pretreatment growth rate of < 2.5 mm/year exhibited a 97% tumor control rate, compared with 69% for those demonstrating ≥ 2.5 mm/year of growth prior to SRS (p = 0.007). No other analyzed variables were found to predict tumor growth following SRS. CONCLUSIONS Overall, SRS administered using a marginal dose between 12-14 Gy is highly effective in treating VSs in which initial observation fails. Tumor control is achieved in 97% of VSs that exhibit slow (< 2.5 mm/year) pretreatment growth; however, SRS is less successful in treating tumors exhibiting rapid growth (≥ 2.5 mm/year).

Pediatric pituitary resection: characterizing surgical approaches and complications.

BACKGROUND: Although there has been extensive study evaluating adult pituitary surgery, there has been scant analysis among children. Our objective was to evaluate a population-based resource to characterize nationwide trends in surgical approach, hospital stay, and complications among children undergoing pituitary surgery. METHODS: The Kids' Inpatient-Database (KID) files (2009/2012) were evaluated for pituitary gland excisions. Procedure, patient demographics, length of inpatient stay, inpatient costs, hospital setting, and surgical complications were analyzed. RESULTS: A weighted incidence of 1071 cases were analyzed; the majority (77.6%) underwent transsphenoidal resections. These patients had significantly decreased hospital costs and lengths of stay. Patients undergoing transfrontal approaches had significantly greater rates of postoperative diabetes insipidus (DI) (66.5%), panhypopituitarism (38.8%), hydrocephalus, and visual deficits. Among transsphenoidal patients, males had greater rates of postoperative hydrocephalus (5.5%) and panhypopituitarism (17.5%) than females, and patients ≤10 years old had greater rates of these 2 complications (14.5%, 19.4%, respectively) as well as DI (61.3%). CONCLUSION: A greater proportion of children undergo transfrontal approaches for pituitary lesions than in their adult counterparts. This difference may harbor a potential to influence future sellar resection approaches in children toward a transsphenoidal operation when surgically feasible. Patients undergoing transfrontal procedures have greater risks for many intraoperative and postoperative complications relative to individuals undergoing transsphenoidal resections. Among patients undergoing transsphenoidal approaches, males had significantly greater rates of postoperative hydrocephalus and panhypopituitarism, and younger children had greater rates of postoperative DI, hydrocephalus, and panhypopituitarism. These data reinforce the need for greater vigilance in the postoperative care of younger children undergoing transsphenoidal surgery.

Stereotactic Radiosurgery for Cystic Vestibular Schwannomas.

BACKGROUND: The optimum treatment for cystic vestibular schwannoma (VS) remains controversial. Anecdotally, many treating physicians feel that cystic VSs do not respond to stereotactic radiosurgery (SRS) as well as noncystic tumors. OBJECTIVE: To present outcomes after treatment of predominantly cystic VS with SRS. METHODS: A prospectively maintained clinical database of patients undergoing Gamma Knife (Elekta Instruments, Stockholm, Sweden) radiosurgery (GKRS) for VS at a single tertiary academic referral center was retrospectively reviewed. Patients diagnosed with cystic VS who were treated with GKRS between 1997 and 2014 were analyzed. Size-matched solid tumors treated with GKRS during this period were selected as controls. RESULTS: Twenty patients (12 women; median age at treatment, 56 years; range, 36-85 years) with cystic VS met inclusion criteria. The median radiologic follow-up within the cystic group was 63 months (range, 17-201 months), and the median change in tumor size was -4.9 mm (range, -10.4 to 9.3 mm). Sixteen tumors (80%) shrank, 2 (10%) remained stable, and 2 (10%) enlarged, accounting for a tumor control rate of 90%. The median radiologic follow-up in the noncystic control group was 67 months (range, 6-141 months), and the median change in size was -2.0 mm (range, -10.4 to 2.5 mm). Tumor control in the solid group was 90%. Comparing only those tumors that decreased in size showed that there was a trend toward a greater reduction within the cystic group ( P = .05). CONCLUSION: The present study demonstrates that tumor control after SRS for cystic VS may not differ from that of noncystic VS in selected cases.

Volumetric analysis of tumor control following subtotal and near-total resection of vestibular schwannoma.

OBJECTIVES/HYPOTHESIS: The primary goals of microsurgery for vestibular schwannoma (VS) include preservation of neural function and complete tumor removal. In a subset of patients, adherent tumor remnant may be intentionally left behind in order to minimize risk of new neurologic deficits. It is not well established if residual tumor volume predicts likelihood of tumor remnant growth. METHODS: Patients with sporadic VS who underwent near-total (NTR) or subtotal (STR) VS resection between 2000 and 2014 were reviewed. Postoperative tumor remnants were volumetrically contoured using T1-weighted gadolinium-enhanced magnetic resonance imaging obtained within 3 months of surgery. RESULTS: A total of 103 patients met study criteria, and the median duration of radiographic follow-up was 41 months (mean 56.1 months, range 12-150 months). Fifty patients underwent NTR and 53 received STR. Overall 14 (13.6%) tumors recurred at a median of 41.0 months. Patients who underwent STR were over 13 times more likely to recur compared with those treated with NTR (hazard ratio 13.31; 95% confidence interval 1.71-103.91; P = 0.014). The median time to recurrence following NTR was 124 months compared to 32 months after STR (P < 0.001). CONCLUSIONS: Long-term follow-up in patients undergoing incomplete resection is essential. Near-total resection has a significantly lower rate of recurrence compared to STR. Maximal surgical resection should be the goal in VS microsurgery. The decision to pursue less than complete resection should be based on intraoperative impression, when it is felt that continued dissection of adherent disease would compromise neurologic outcome. LEVEL OF EVIDENCE: 4. Laryngoscope, 126:1877-1882, 2016.

The Short-Term and Intermediate-Term Risk of Second Neoplasms After Diagnosis and Treatment of Unilateral Vestibular Schwannoma: Analysis of 9460 Cases.

PURPOSE: To determine the incidence of second intracranial neoplasms after the diagnosis and treatment of sporadic vestibular schwannoma (VS). METHODS AND MATERIALS: Analysis of the Surveillance, Epidemiology, and End Results (SEER) database including all patients identified with a diagnosis of VS and a second intracranial tumor. The Kaplan-Meier method was used to determine the incidence of second tumors while allowing for censoring at loss to follow-up or death. Multivariable associations between treatment modality and second tumor formation were explored using Cox proportional hazards regression analysis. Two illustrative cases are also presented. RESULTS: In all, 9460 patients with unilateral VS were identified between 2004 and 2012. Overall, 66 (0.7%) patients experienced a separate intracranial tumor, benign or malignant, after treatment of VS. Kaplan-Meier estimates for time to second neoplasm at 1, 3, and 5 years were 0.3%, 0.7%, and 0.8%, respectively. Multivariable comparison between VS treatment modalities revealed that the risk of second tumor formation was similar between radiation and surgery (hazard ratio [HR] 0.74; 95% confidence interval [CI] 0.36-1.51; P=.93) but greater for tumors managed with observation alone compared with radiation (HR 2.48; 95% CI 1.31-4.71; P<.01). A total of 6 (0.06%) intracranial malignancies were diagnosed after VS treatment. Kaplan-Meier estimates for time to malignancy at 1, 3, and 5 years were 0%, 0.1%, and 0.1%, respectively. After adjustment for age at diagnosis, sex, and treatment modality, the probability of malignancy after radiation was not greater than after observation alone or microsurgery (HR 4.88; 95% CI 0.85-28.14; P=.08) during the study period. CONCLUSIONS: The risk for the development of a second intracranial neoplasm, benign or malignant, at 5 years after treatment of unilateral VS is approximately 0.8%, whereas the risk of acquiring a separate malignancy is 0.1%, or approximately 1 per 1000 cases. The short-term and intermediate-term incidence of second neoplasm after radiation of VS is not greater than the incidence after microsurgery or observation.

Temporal Lobe Gliosarcoma After Gamma Knife Radiosurgery for Vestibular Schwannoma.

OBJECTIVE: Secondary tumorigenesis after exposure to ionizing radiation is a well-described phenomenon. The probability of developing a malignancy after stereotactic radiosurgery (SRS) is theoretically less than conventional external beam radiation therapy; however, the exact risk remains unknown. Such information is important for patient counseling when considering treatment of benign conditions such as vestibular schwannoma (VS). The objective of the current report is to describe a case of a temporal lobe gliosarcoma developing 3 years after radiosurgical treatment of a sporadic VS. SETTING: Tertiary academic referral center. PATIENT: A 54-year-old man was diagnosed with a left-sided 1.6 cm cerebellopontine angle mass, consistent with VS. After reviewing treatment options, the patient proceeded with radiosurgery, and a tumor volume of 2.4 cm was treated with a marginal dose of 12.5 Gy prescribed to the 50% isodose line. RESULTS: Serial magnetic resonance imaging (MRI) revealed good treatment response, demonstrated by central necrosis and tumor shrinkage. However, 3 years after treatment, the patient presented to the emergency department for a month long history of progressive word finding difficulties. Imaging revealed a 5 cm temporal lobe mass consistent with a high-grade glial neoplasm. He subsequently underwent stereotactic resection and final pathology confirmed World Health Organization Grade IV gliosarcoma. CONCLUSION: De novo malignancy after radiosurgery for VS is rare. We present only the second case of a gliosarcoma arising within the low-dose radiation field of the radiosurgery treatment plan. Some of the challenges of establishing causality between radiation treatment and secondary tumor development are discussed. The reporting of malignancy after radiation therapy, and even microsurgery, warrants continued vigilance.

Malignant peripheral nerve sheath tumors of the eighth cranial nerve arising without prior irradiation.

OBJECTIVE Malignant peripheral nerve sheath tumors (MPNSTs) of the eighth cranial nerve (CN) are exceedingly rare. To date the literature has focused on MPNSTs occurring after radiation therapy for presumed benign vestibular schwannomas (VSs), while MPNSTs arising without prior irradiation have received little attention. The objectives of the current study are to characterize the epidemiology, clinical presentation, disease course, and outcome using a large national cancer registry database and a systematic review of the English literature. Additionally, a previously unreported case is presented. METHODS The authors conducted an analysis of the Surveillance, Epidemiology, and End Results (SEER) database, a systematic review of the literature, and present a case report. Data from all patients identified in the SEER database with a diagnosis of MPNST involving the eighth CN, without a history of prior radiation, were analyzed. Additionally, all cases reported in the English literature between January 1980 and March 2015 were reviewed. Finally, 1 previously unreported case is presented. RESULTS The SEER registries identified 30 cases between 1992 and 2012. The average incidence was 0.017 per 1 million persons per year (range 0.000-0.0687 per year). The median age at diagnosis was 55 years, and 16 (53%) were women. Thirteen cases were diagnosed upon autopsy. Of the 17 cases diagnosed while alive, the median follow-up was 118 days, with 3 deaths (18%) observed. When compared with the incidence of benign VS, 1041 VSs present for every 1 MPNST arising from the eighth CN. Including a previously unreported case from the authors' center, a systematic review of the English literature yielded 24 reports. The median age at diagnosis was 44 years, 50% were women, and the median tumor size at diagnosis was 3 cm. Eleven patients (46%) reported isolated audiovestibular complaints typical for VS while 13 (54%) exhibited facial paresis or other signs of a more aggressive process. Treatment included microsurgery alone, microsurgery with adjuvant radiation, or microsurgery with chemoradiation. Sixty-one percent of patients receiving treatment experienced recurrence, 22% of which were diagnosed with drop metastases to the spine. Ultimately, 13 patients (54%) died of progressive disease at a median of 3 months following diagnosis. The ability to achieve gross-total resection was the only feature that was associated with improved disease-specific survival. CONCLUSIONS MPNSTs of the eighth CN are extremely rare and portend a poor prognosis. Nearly half of patients initially present with findings consistent with a benign VS, often making an early diagnosis challenging. In light of these data, early radiological and clinical follow-up should be considered in those who elect nonoperative treatment, particularly in patients with a short duration of symptoms or atypical presentation. These data also provide a baseline rate of malignancy that should be considered when estimating the risk of malignant transformation following stereotactic radiosurgery for VS.

Penetrating head injuries in children due to BB and pellet guns: a poorly recognized public health risk.

OBJECT Nonpowder guns, defined as spring- or gas-powered BB or pellet guns, can be dangerous weapons that are often marketed to children. In recent decades, advances in compressed-gas technology have led to a significant increase in the power and muzzle velocity of these weapons. The risk of intracranial injury in children due to nonpowder weapons is poorly documented. METHODS A retrospective review was conducted at 3 institutions studying children 16 years or younger who had intracranial injuries secondary to nonpowder guns. RESULTS The authors reviewed 14 cases of intracranial injury in children from 3 institutions. Eleven (79%) of the 14 children were injured by BB guns, while 3 (21%) were injured by pellet guns. In 10 (71%) children, the injury was accidental. There was 1 recognized assault, but there were no suicide attempts; in the remaining 3 patients, the intention was indeterminate. There were no mortalities among the patients in this series. Ten (71%) of the children required operative intervention, and 6 (43%) were left with permanent neurological injuries, including epilepsy, cognitive deficits, hydrocephalus, diplopia, visual field cut, and blindness. CONCLUSIONS Nonpowder guns are weapons with the ability to penetrate a child's skull and brain. Awareness should be raised among parents, children, and policy makers as to the risk posed by these weapons.