Jeffrey T. Jacob

Long-term hearing outcomes following stereotactic radiosurgery for vestibular schwannoma: patterns of hearing loss and variables influencing audiometric decline

OBJECT The goals of this retrospective cohort study were as follows: 1) to describe the long-term prevalence and timing of hearing deterioration following low-dose (12- to 13-Gy marginal dose) stereotactic radiosurgery (SRS) for vestibular schwannoma (VS); and 2) to identify clinical variables associated with long-term preservation of useful hearing following treatment. METHODS Patients with serviceable hearing who underwent SRS for VS between 1997 and 2002 were studied. Data including radiosurgery treatment plans, tumor characteristics, pre- and posttreatment pure tone average, speech discrimination scores, and American Academy of Otolaryngology-Head and Neck Surgery hearing class were collected. Time to nonserviceable hearing was estimated using the Kaplan-Meier method. Univariate and multivariate associations with time to nonserviceable hearing were evaluated using Cox proportional hazards regression models. RESULTS Forty-four patients met the study criteria and were included. The median duration of audiometric follow-up was 9.3 years. Thirty-six patients developed nonserviceable hearing at a mean of 4.2 years following SRS. The Kaplan-Meier estimated rates of serviceable hearing at 1, 3, 5, 7, and 10 years following SRS were 80%, 55%, 48%, 38%, and 23%, respectively. Multivariate analysis revealed that pretreatment ipsilateral pure tone average (p < 0.001) and tumor size (p = 0.009) were statistically significantly associated with time to nonserviceable hearing. CONCLUSIONS Durable hearing preservation a decade after low-dose SRS for VS occurs in less than one-fourth of patients. Variables including preoperative hearing capacity and tumor size may be used to predict hearing outcomes following treatment. These findings may assist in pretreatment risk disclosure. Furthermore, these data demonstrate the importance of long-term follow-up when reporting audiometric outcomes following SRS for VS.

The Changing Landscape of Vestibular Schwannoma Management in the United States—A Shift Toward Conservatism

Objective To characterize the evolving management of vestibular schwannoma (VS) in the United States. Study Design Retrospective analysis of the Surveillance, Epidemiology, and End Results (SEER) database. Setting SEER database. Subjects and Methods All patients with a diagnosis of VS were analyzed. Data were described and compared using trend analyses and univariate and multivariable logistic regression. Results A total of 8330 patients (average age 54.7 years, 51.9% female) were analyzed. The mean incidence was approximately 1.1 per 100,000 per year and did not vary significantly across time; however, from 2004 to 2011, there was a statistically significant decrease in tumor size category at time of diagnosis (P < .01). Overall, 3982 patients (48%) received primary microsurgery, 1978 (24%) radiation therapy alone, and 2370 (29%) observation. Within the microsurgical cohort, 732 (18%) underwent subtotal resection, and of those, 98 (13.4%) received postoperative radiation therapy. Multivariable regression revealed that surgical treatment was more common in younger patients and larger tumor size categories (P < .05). Management trend analysis revealed that microsurgery was used less frequently over time (P < .0001), observation was used more frequently (P < .0001), and the pattern of radiation therapy remained unchanged. Linear regression was used to create an equation that was applied to predict future management practices. These data predict that by 2026, half of all cases of VS will be managed initially with observation. Conclusion While the incidence of VS has remained steady, tumor size at time of diagnosis has decreased over time. Within the United States there has been a clear, recent evolution in management toward observation.

Significance of cochlear dose in the radiosurgical treatment of vestibular schwannoma: controversies and unanswered questions.

BACKGROUND Cochlear dose has been identified as a potentially modifiable contributor to hearing loss after stereotactic radiosurgery (SRS) for vestibular schwannoma (VS). OBJECTIVE To evaluate the association between computed tomography-based volumetric cochlear dose and loss of serviceable hearing after SRS, to assess intraobserver and interobserver reliability when determining modiolar point dose with the use of magnetic resonance imaging and computed tomography, and to discuss the clinical significance of the cochlear dose with regard to radiosurgical planning strategy. METHODS Patients with serviceable pretreatment hearing who underwent SRS for sporadic VS between the use of Gamma Knife Perfexion were studied. Univariate and multivariate associations with the primary outcome of time to nonserviceable hearing were evaluated. RESULTS A total of 105 patients underwent SRS for VS during the study period, and 59 (56%) met study criteria and were analyzed. Twenty-one subjects (36%) developed nonserviceable hearing at a mean of 2.2 years after SRS (SD, 1.0 years; median, 2.1 years; range 0.6-3.8 years). On univariate analysis, pretreatment pure tone average, speech discrimination score, American Academy of Otolaryngology-Head and Neck Surgery hearing class, marginal dose, and mean dose to the cochlear volume were statistically significantly associated with time to nonserviceable hearing. However, after adjustment for baseline differences, only pretreatment pure tone average was statistically significantly associated with time to nonserviceable hearing in a multivariable model. CONCLUSION Cochlear dose is one of many variables associated with hearing preservation after SRS for VS. Until further studies demonstrate durable tumor arrest with reduced dose protocols, routine tumor dose planning should not be modified to limit cochlear dose at the expense of tumor control.

Understanding the impact of obesity on short-term outcomes and in-hospital costs after instrumented spinal fusion

BACKGROUND Obesity rates continue to rise along with the number of obese patients undergoing elective spinal fusion. OBJECTIVE To evaluate the impact of obesity on resource utilization and early complications in patients undergoing surgery for degenerative spine disease. METHODS A single-institution retrospective analysis was conducted on patients with degenerative spine disease requiring instrumentation between 2008 and 2012. The 801 identified patients were grouped based on a body mass index (BMI) of <30 (nonobese, n = 478), ≥30 and <40 (obese, n = 283), and alternatively BMIs of ≥40 (morbidly obese, n = 40). Baseline characteristics, surgical outcomes and requirements, complications, and cost were compared. Logistic and linear regression analyses were used to determine the strength of association between obesity and outcomes for categorical and continuous data, respectively. RESULTS Significant differences were found in comorbidities between cohorts. Multivariate analysis revealed significant associations between obesity and longer anesthesia times (30 minutes, P = .008), and surgical times (24 minutes, P = .02). Additionally, there was a 2.8 times higher rate of wound complications in obese patients (4.2% vs 1.5, P = .03), and 2.5 times higher rate of major medical complications (7.8% vs 3.1, P = .01). Morbid obesity resulted in a 10 times higher rate of wound complications (P < .001). Morbid obesity resulted in a

Facial Nerve Schwannomas of the Cerebellopontine Angle: The Mayo Clinic Experience

9078 (P = .005) increase in overall cost of care. CONCLUSION Increased BMI is associated with longer operative times, increased complication rates, and increased cost independent of comorbidities. These effects are more pronounced with morbidly obese patients, further supporting a role for preoperative weight loss.

The Impact of Obesity on Perioperative Resource Utilization after Elective Spine Surgery for Degenerative Disease

Background There is often controversy regarding the optimal management for patients with facial nerve schwannomas (FNSs) of the cerebellopontine angle (CPA). Methods The clinical and radiological outcomes in 14 patients with CPA FNS were retrospectively reviewed. Results Patients underwent resection with anatomic nerve preservation (n = 3), facial-hypoglossal nerve anastomosis (n = 4), gamma knife radiosurgery (GKS) (n = 6), or observation (n = 1). A total of 83% of tumors that underwent GKS were stable or decreased in size. No patient who underwent resection showed evidence of tumor recurrence; the tumor under observation remained unchanged with normal facial function at the time of the last follow-up. Facial function was decreased in 57%, stable in 14%, and improved in 29% of those who underwent microsurgery. A total of 67% of patients who underwent GKS had stable facial function. Serviceable hearing was maintained in 50% of patients in the GKS group and 67% of the tumor resection group. Mean and median follow-up was 48 and 43 months, respectively (range, 12 to 95 months). Conclusion Observation should be the primary management when encountered with FNS of the CPA in those with good neurologic function. Microsurgery or radiosurgery may be used in those with poor facial function or tumor progression.

In-Hospital Neurologic Deterioration Following Fractures of the Ankylosed Spine: A Single-Institution Experience

Study Design Retrospective case series. Objective To determine the effect of obesity on the resource utilization and cost in 3270 consecutive patients undergoing elective noninstrumented decompressive surgeries for degenerative spine disease at Mayo Clinic Rochester between 2005 and 2012. Methods Groups were assessed for baseline differences (age, gender, and American Society of Anesthesiologists [ASA] classification, procedure type, and number of operative levels). Outcome variables included the transfusion requirements during surgery, the total anesthesia and surgical times, intensive care unit (ICU) admissions, standardized costs, as well as the ICU and hospital length of stay (LOS). Regression analysis was used to evaluate for strength of association between obesity and outcome variables. Results Baseline differences between the groups (nonobese: n = 1,853; obese: n = 1,417) were found with respect to age, ASA class, gender, procedure type, and number of operative levels. After correcting for differences, we found significant associations between obesity and surgical (p < 0.0001) and anesthesia times (p < 0.0001) and hospital LOS (p < 0.0001). Additionally, ICU admission rates (p = 0.02) and requirement for postoperative ventilation (p = 0.048) were significantly higher in obese patients. Finally, mean difference in total cost (

Stereotactic Radiosurgery in the Management of Vestibular Schwannoma and Glomus Jugulare: Indications, Techniques, and Results

1,632, p < 0.0001) was significantly higher for the obese cohort. Conclusion Obesity is associated with increased resource utilization and cost in patients undergoing a noninstrumented decompressive surgery for degenerative spine disease.

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

OBJECTIVE To determine the rate and severity of in-hospital neurologic deterioration following vertebral fractures of spinal hyperostosis. METHODS A retrospective review of 92 fractures in 81 patients with diffuse idiopathic skeletal hyperostosis (42%) or ankylosing spondylitis (58%) was performed. Data on demographics, comorbidities, and fracture and treatment characteristics were recorded. Neurologic presentation and outcomes were categorized using American Spinal Injury Association grades and the modified Rankin Scale. Univariate and multivariate analyses were used to identify risk factors for neurologic deterioration or poor outcome (modified Rankin Scale 4-6). RESULTS Most fractures (66%) occurred after falls of standing height or less. Presentation was delayed in 41% of patients (median 7 days), and diagnosis was delayed in 21% (median 8 days). Most fractures were extension (60%) or distraction (78%) injuries involving all 3 spinal columns. Median Subaxial Cervical Spine Injury Classification and Thoracolumbar Injury Severity Scale scores were 6 (interquartile range 5-7) and 7 (interquartile range 6-8), respectively. Of patients, 62% underwent open operative fusion either as initial therapy or after failed conservative treatment, 20% had percutaneous instrumentation, and 27% were treated in an external orthosis (52% required open fusion). Neurologic deterioration after presentation occurred in 7 patients (8.6%); 5 of these patients deteriorated after surgical treatment, constituting a 7.6% surgical risk. The presenting American Spinal Injury Association grade and patient age predicted poor outcome at 1-year outcome (P < 0.001). Death occurred in 17 patients within 1 year of injury (23%). CONCLUSIONS Neurologic deterioration during the initial hospitalization after spinal fractures in the setting of diffuse idiopathic skeletal hyperostosis or ankylosing spondylitis is common, and 1-year mortality is high.

Intramedullary spinal cord gangliocytoma: case report and a review of the literature.

Gamma Knife stereotactic radiosurgery (GKS) has become an important management strategy for an increasing number of patients with skull base tumors. For select patients with lateral skull base disorders, given the proximity to sensitive critical structures such as the brainstem, cranial nerves, and cochlea, this technology has emerged as a first-line treatment to achieve the paramount goals of long-term tumor control and maintenance of existing neurologic function. This article reviews the indications, technique, and results of GKS for the treatment of vestibular schwannoma and glomus jugulare tumors, and highlights our experience in treating these tumors at the Mayo Clinic.