Symeon Missios

Radiosurgery for Cerebral Arteriovenous Malformations in A Randomized Trial of Unruptured Brain Arteriovenous Malformations (ARUBA)-Eligible Patients A Multicenter Study

Background and Purpose— The benefit of intervention for patients with unruptured cerebral arteriovenous malformations (AVMs) was challenged by results demonstrating superior clinical outcomes with conservative management from A Randomized Trial of Unruptured Brain AVMs (ARUBA). The aim of this multicenter, retrospective cohort study is to analyze the outcomes of stereotactic radiosurgery for ARUBA-eligible patients. Methods— We combined AVM radiosurgery outcome data from 7 institutions participating in the International Gamma Knife Research Foundation. Patients with ≥12 months of follow-up were screened for ARUBA eligibility criteria. Favorable outcome was defined as AVM obliteration, no postradiosurgery hemorrhage, and no permanently symptomatic radiation–induced changes. Adverse neurological outcome was defined as any new or worsening neurological symptoms or death. Results— The ARUBA-eligible cohort comprised 509 patients (mean age, 40 years). The Spetzler–Martin grade was I to II in 46% and III to IV in 54%. The mean radiosurgical margin dose was 22 Gy and follow-up was 86 months. AVM obliteration was achieved in 75%. The postradiosurgery hemorrhage rate during the latency period was 0.9% per year. Symptomatic and permanent radiation–induced changes occurred in 11% and 3%, respectively. The rates of favorable outcome, adverse neurological outcome, permanent neurological morbidity, and mortality were 70%, 13%, 5%, and 4%, respectively. Conclusions— Radiosurgery may provide durable clinical benefit in some ARUBA-eligible patients. On the basis of the natural history of untreated, unruptured AVMs in the medical arm of ARUBA, we estimate that a follow-up duration of 15 to 20 years is necessary to realize a potential benefit of radiosurgical intervention for conservative management in unruptured patients with AVM.

Stereotactic radiosurgery for cerebral arteriovenous malformations: evaluation of long-term outcomes in a multicenter cohort.

OBJECTIVE In this multicenter study, the authors reviewed the results following Gamma Knife radiosurgery (GKRS) of cerebral arteriovenous malformations (AVMs), determined predictors of outcome, and assessed predictive value of commonly used grading scales based upon this large cohort with long-term follow-up. METHODS Data from a cohort of 2236 patients undergoing GKRS for cerebral AVMs were compiled from the International Gamma Knife Research Foundation. Favorable outcome was defined as AVM obliteration and no posttreatment hemorrhage or permanent symptomatic radiation-induced complications. Patient and AVM characteristics were assessed to determine predictors of outcome, and commonly used grading scales were assessed. RESULTS The mean maximum AVM diameter was 2.3 cm, with a mean volume of 4.3 cm3. A mean margin dose of 20.5 Gy was delivered. Mean follow-up was 7 years (range 1-20 years). Overall obliteration was 64.7%. Post-GRKS hemorrhage occurred in 165 patients (annual risk 1.1%). Radiation-induced imaging changes occurred in 29.2%; 9.7% were symptomatic, and 2.7% had permanent deficits. Favorable outcome was achieved in 60.3% of patients. Patients with prior nidal embolization (OR 2.1, p < 0.001), prior AVM hemorrhage (OR 1.3, p = 0.007), eloquent location (OR 1.3, p = 0.029), higher volume (OR 1.01, p < 0.001), lower margin dose (OR 0.9, p < 0.001), and more isocenters (OR 1.1, p = 0.011) were more likely to have unfavorable outcomes in multivariate analysis. The Spetzler-Martin grade and radiosurgery-based AVM score predicted outcome, but the Virginia Radiosurgery AVM Scale provided the best assessment. CONCLUSIONS GKRS for cerebral AVMs achieves obliteration and avoids permanent complications in the majority of patients. Patient, AVM, and treatment parameters can be used to predict long-term outcomes following radiosurgery.

Predicting inpatient complications from cerebral aneurysm clipping: the Nationwide Inpatient Sample 2005–2009

OBJECT Precise delineation of individualized risks of morbidity and mortality is crucial in decision making in cerebrovascular neurosurgery. The authors attempted to create a predictive model of complications in patients undergoing cerebral aneurysm clipping (CAC). METHODS The authors performed a retrospective cohort study of patients who had undergone CAC in the period from 2005 to 2009 and were registered in the Nationwide Inpatient Sample (NIS) database. A model for outcome prediction based on preoperative individual patient characteristics was developed. RESULTS Of the 7651 patients in the NIS who underwent CAC, 3682 (48.1%) had presented with unruptured aneurysms and 3969 (51.9%) with subarachnoid hemorrhage. The respective inpatient postoperative risks for death, unfavorable discharge, stroke, treated hydrocephalus, cardiac complications, deep vein thrombosis, pulmonary embolism, and acute renal failure were 0.7%, 15.3%, 5.3%, 1.5%, 1.3%, 0.6%, 2.0%, and 0.1% for those with unruptured aneurysms and 11.5%, 52.8%, 5.5%, 39.2%, 1.7%, 2.8%, 2.7%, and 0.8% for those with ruptured aneurysms. Multivariate analysis identified risk factors independently associated with the above outcomes. A validated model for outcome prediction based on individual patient characteristics was developed. The accuracy of the model was estimated using the area under the receiver operating characteristic curve, and it was found to have good discrimination. CONCLUSIONS The featured model can provide individualized estimates of the risks of postoperative complications based on preoperative conditions and can potentially be used as an adjunct in decision making in cerebrovascular neurosurgery.

Prehospital Helicopter Transport and Survival of Patients With Traumatic Brain Injury

OBJECTIVE To investigate the association of helicopter transport with survival of patients with traumatic brain injury (TBI), in comparison with ground emergency medical services (EMS). BACKGROUND Helicopter utilization and its effect on the outcomes of TBI remain controversial. METHODS We performed a retrospective cohort study involving patients with TBI who were registered in the National Trauma Data Bank between 2009 and 2011. Regression techniques with propensity score matching were used to investigate the association of helicopter transport with survival of patients with TBI, in comparison with ground EMS. RESULTS During the study period, there were 209,529 patients with TBI who were registered in the National Trauma Data Bank and met the inclusion criteria. Of these patients, 35,334 were transported via helicopters and 174,195 via ground EMS. For patients transported to level I trauma centers, 2797 deaths (12%) were recorded after helicopter transport and 8161 (7.8%) after ground EMS. Multivariable logistic regression analysis demonstrated an association of helicopter transport with increased survival [OR (odds ratio), 1.95; 95% confidence interval (CI), 1.81-2.10; absolute risk reduction (ARR), 6.37%]. This persisted after propensity score matching (OR, 1.88; 95% CI, 1.74-2.03; ARR, 5.93%). For patients transported to level II trauma centers, 1282 deaths (10.6%) were recorded after helicopter transport and 5097 (7.3%) after ground EMS. Multivariable logistic regression analysis demonstrated an association of helicopter transport with increased survival (OR, 1.81; 95% CI, 1.64-2.00; ARR 5.17%). This again persisted after propensity score matching (OR, 1.73; 95% CI, 1.55-1.94; ARR, 4.69). CONCLUSIONS Helicopter transport of patients with TBI to level I and II trauma centers was associated with improved survival, in comparison with ground EMS.

Inpatient Outcomes and Postoperative Complications After Primary Versus Revision Lumbar Spinal Fusion Surgeries for Degenerative Lumbar Disc Disease: A National (Nationwide) Inpatient Sample Analysis, 2002–2011

INTRODUCTION The present study investigates outcomes in patients undergoing elective primary versus revision fusion surgery for lumbar degenerative pathologies with the use of a large population based database. METHODS A total of 126,044 patients registered in the National Inpatient Sample (NIS) database were identified to have undergone elective fusion of the lumbar spine (primary fusion: 94%; redo fusion: 6%) for degenerative pathologies, between 2002 and 2011. A multivariable logistic regression model was built that adjusted for patient demographics and clinical and hospital characteristics to explore clinical outcomes and postoperative complications. RESULTS The mean age of the cohort was 54.91 ± 13.98 years, and 58% were women. Multivariable regression analysis revealed patients undergoing redo lumbar fusion had a greater likelihood for an unfavorable discharge (odds ratio [OR] 1.17; 95% confidence interval [95% CI] 1.08-1.26; P < 0.0001), prolonged length of stay (OR: 1.80; 95% CI 1.68-1.92; P < 0.0001), greater hospital charges (OR 1.60; 95% CI 1.51-1.71; P < 0.0001), neurologic complications including dural tears and nerve root injuries (OR 2.06; 95% CI 1.80-2.37; P < 0.0001), deep venous thrombosis (OR 2.35; 95% CI 1.76-3.14; P < 0.0001), pulmonary embolism (OR 1.72; 95% CI 1.45-2.03; P < 0.0001), would infections (OR 2.40; 95% CI 1.79-3.22; P < 0.0001) and wound complications (OR 1.59; 95% CI 1.32-1.91; P < 0.0001), and gastrointestinal complications (OR 1.23; 95% CI 1.04-1.45; P = 0.016), compared with patients undergoing a primary lumbar fusion procedure. CONCLUSIONS The association of a likely postoperative complication in patients undergoing revision lumbar spine fusion compared with those undergoing primary fusion procedures at the same region of the spine is quantified. Our analysis provides baseline estimates that could aid in preoperative risk stratification and as an adjunct in patient education and counseling, and policy makers for higher reimbursements for these sicker patients.

International multicenter cohort study of pediatric brain arteriovenous malformations. Part 1: Predictors of hemorrhagic presentation

OBJECTIVE Brain arteriovenous malformations (AVMs) are the most common cause of spontaneous intracranial hemorrhage in pediatric patients (age < 18 years). Since the cumulative lifetime risk of AVM hemorrhage is considerable in children, an improved understanding of the risk factors influencing hemorrhagic presentation may aid in the management of pediatric AVMs. The aims of this first of a 2-part multicenter, retrospective cohort study are to evaluate the incidence and determine the predictors of hemorrhagic presentation in pediatric AVM patients. METHODS The authors analyzed pooled AVM radiosurgery data from 7 institutions participating in the International Gamma Knife Research Foundation (IGKRF). Patients younger than 18 years at the time of radiosurgery and who had at least 12 months of follow-up were included in the study cohort. Patient and AVM characteristics were compared between unruptured and ruptured pediatric AVMs. RESULTS A total of 357 pediatric patients were eligible for analysis, including 112 patients in the unruptured and 245 patients in the ruptured AVM cohorts (69% incidence of hemorrhagic presentation). The annual hemorrhage rate prior to radiosurgery was 6.3%. Hemorrhagic presentation was significantly more common in deep locations (basal ganglia, thalamus, and brainstem) than in cortical locations (frontal, temporal, parietal, and occipital lobes) (76% vs 62%, p = 0.006). Among the factors found to be significantly associated with hemorrhagic presentation in the multivariate logistic regression analysis, deep venous drainage (OR 3.2, p < 0.001) was the strongest independent predictor, followed by female sex (OR 1.7, p = 0.042) and smaller AVM volume (OR 1.1, p < 0.001). CONCLUSIONS Unruptured and ruptured pediatric AVMs have significantly different patient and nidal features. Pediatric AVM patients who possess 1 or more of these high-risk features may be candidates for relatively more aggressive management strategies.

Selection of patients for ambulatory lumbar discectomy: results from four US states

BACKGROUND CONTEXT There is a persistent trend for more outpatient lumbar discectomies in the United States. PURPOSE To investigate the characteristics of the patients selected for ambulatory procedures. STUDY DESIGN Retrospective cohort study. PATIENT SAMPLE Forty-seven thousand one hundred twenty-five patients who underwent outpatient and 102,592 patients undergoing inpatient lumbar discectomies and were were registered in the State Ambulatory Surgery Database (SASD) and State Inpatient Database (SID), respectively, for New York, California, Florida, and North Carolina from 2005 to 2008. OUTCOME MEASURES Rate of outpatient procedures, 30-day readmissions, and hospital charges. METHODS We performed a retrospective cohort study involving patients who underwent outpatient and inpatient lumbar discectomies and were registered in SASD and SID, respectively, for New York, California, Florida, and North Carolina from 2005 to 2008. Logistic regression models were used to demonstrate the association of socioeconomic factors with the odds of undergoing an outpatient procedure. RESULTS Male gender (odds ratio [OR], 1.05; 95% confidence interval [CI], 1.03-1.08), private insurance (OR, 1.93; 95% CI, 1.86-2.01), lower Charlson Comorbidity Index (OR, 4.04; 95% CI, 3.17-5.16), and higher volume hospitals (OR, 1.06; 95% CI, 1.04-1.08) were significantly associated with outpatient procedures. Higher income (OR, 0.83; 95% CI, 0.81-0.85), older age (OR, 0.996; 95% CI, 0.995-0.997), coverage by Medicaid (OR, 0.89; 95% CI, 0.83-0.96), African Americans (OR, 0.65; 95% CI, 0.60-0.70), and other minority races were associated with decreased odds of outpatient procedures. The rate of 30-day postoperative readmissions was higher among inpatients. Institutional charges were significantly lower for outpatient lumbar discectomies. The median charge for inpatient surgery was

Hospitalization cost after spine surgery in the United States of America.

24,273 as compared with

International multicenter cohort study of pediatric brain arteriovenous malformations. Part 2: Outcomes after stereotactic radiosurgery.

11,339 for the outpatient setting (p<.0001). CONCLUSIONS Access to ambulatory lumbar discectomies appears to be more common for younger, white, male patients, with private insurance and less comorbidities, in the setting of higher volume hospitals. Further investigation is needed in the direction of mapping these disparities for appropriate resource utilization.

How well do subjective Hospital Compare metrics reflect objective outcomes in spine surgery

The objective of this study was to develop and validate a predictive model of hospitalization costs after spine surgery. Several initiatives have been put in place to minimize healthcare expenditures but there are limited data on the magnitude of the contribution of procedure-specific drivers of cost. We performed a retrospective cohort study involving 672,591 patients who underwent spine surgery and were registered in the National Inpatient Sample from 2005-2010. The cohort underwent 1:1 randomization to create derivation and validation subsamples. Regression techniques were used for the creation of a parsimonious predictive model of total hospitalization cost after spine surgery. Included were 356,783 patients (53.1%) who underwent fusions, and 315,808 (46.9%) non-fusion surgeries. The median hospitalization cost was