Austin, TX, United States
Austin, TX, United States

Time filter

Source Type

Lewis D.J.,University of Pennsylvania | Lewis D.J.,Baylor College of Medicine | Attiah M.A.,University of Pennsylvania | Malhotra N.R.,University of Pennsylvania | And 2 more authors.
Spine | Year: 2014

STUDY DESIGN. Cost-effectiveness analysis with decision analysis and meta-analysis. OBJECTIVE. To determine the relative cost-effectiveness of anterior cervical discectomy with fusion (with autograft, allograft, or spacers), anterior cervical discectomy without fusion (ACD), and cervical disc replacement (CDR) for the treatment of 1-level cervical disc disease. SUMMARY OF BACKGROUND DATA. There is debate as to the optimal anterior surgical strategy to treat single-level cervical disc disease. Surgical strategies include 3 techniques of anterior cervical discectomy with fusion (autograft, allograft, or spacer-assisted fusion), ACD, and CDR. Several controlled trials have compared these treatments but have yielded mixed results. Decision analysis provides a structure for making a quantitative comparison of the costs and outcomes of each treatment. METHODS. A literature search was performed and yielded 156 case series that fulfilled our search criteria describing nearly 17,000 cases. Data were abstracted from these publications and pooled meta-analytically to estimate the incidence of various outcomes, including index-level and adjacent-level reoperation. A decision analytic model calculated the expected costs in US dollars and outcomes in quality-adjusted life years for a typical adult patient with 1-level cervical radiculopathy subjected to each of the 5 approaches. RESULTS. At 5 years postoperatively, patients who had undergone ACD alone had significantly (P < 0.001) more quality-adjusted life years (4.885 ± 0.041) than those receiving other treatments. Patients with ACD also exhibited highly significant (P < 0.001) differences in costs, incurring the lowest societal costs ($16,558 ± $539). Follow-up data were inadequate for comparison beyond 5 years. CONCLUSION. The results of our decision analytic model indicate advantages for ACD, both in effectiveness and costs, over other strategies. Thus, ACD is a cost-effective alternative to anterior cervical discectomy with fusion and CDR in patients with single-level cervical disc disease. Definitive conclusions about degenerative changes after ACD and adjacent-level disease after CDR await longer follow-up. Level of Evidence: 4. © 2014 by Lippincott Williams & Wilkins.

Burnett M.G.,NeuroTexas Institute | Stein S.C.,University of Pennsylvania | Bartels R.H.M.A.,Radboud University Nijmegen
Journal of Neurosurgery: Spine | Year: 2010

Object. Standard treatment options for patients with lumbar spinal stenosis include nonoperative therapies as well as decompressive laminectomy. The introduction of interspinous decompression devices such as the X-STOP has broadened treatment options, but data comparing these treatment strategies are lacking. The object of this study was to provide a cost-effectiveness analysis of laminectomy, interspinous decompression, and nonoperative treatment for patients with lumbar stenosis. Methods. The authors performed a structured literature review of lumbar stenosis and constructed a cost-effectiveness model. Using conservative treatment, decompressive laminectomy, and placement of X-STOP as the treatment arms, their primary analysis evaluated the optimal treatment strategy for a patient with lumbar stenosis at a 2-year time horizon. Secondary analyses were done to compare cases in which patients required single-level procedures with those in which multilevel procedures were required as well as to examine the outcomes for a 4-year time horizon. Outcomes were calculated using quality-adjusted life years and costs were considered from the perspective of society. Results. Laminectomy was found to be the most effective treatment strategy, followed by X-STOP and then conservative treatment at a 2-year time horizon. Both surgical procedures were more costly than conservative treatment. Because laminectomy was both more effective and less costly than X-STOP, it is said to dominate overall. When single level procedures were considered alone, laminectomy was more effective but also more costly than X-STOP. Conclusions. Lumbar laminectomy appears to be the most cost-effective treatment strategy for patients with symptomatic lumbar spinal stenosis.

Buchanan R.J.,Seton Brain and Spine Institute | Buchanan R.J.,University of Texas at Austin | Darrow D.P.,University of Minnesota | Meier K.T.,University of Utah | And 7 more authors.
Frontiers in Human Neuroscience | Year: 2014

Until now direct neurochemical measurements during memory tasks have not been accomplished in the human basal ganglia. It has been proposed, based on both functional imaging studies and psychometric testing in normal subjects and in patients with Parkinson's disease (PD), that the basal ganglia is responsible for the performance of feedback-contingent implicit memory tasks. To measure neurotransmitters, we used in vivo microdialysis during deep brain stimulation (DBS) surgery. We show in the right subthalamic nucleus (STN) of patients with PD a task-dependent change in the concentrations of glutamate and GABA during an implicit memory task relative to baseline, while no difference was found between declarative memory tasks. The five patients studied had a significant decrease in the percent concentration of GABA and glutamate during the performance of the weather prediction task (WPT). We hypothesize, based on current models of basal ganglia function, that this decrease in the concentration is consistent with expected dysfunction in basal ganglia networks in patients with PD. © 2014 Buchanan, Darrow, Meier, Robinson, Schiehser, Glahn and Nadasdy.

Shpak M.,NeuroTexas Institute | Shpak M.,University of Texas at Austin | Hall A.W.,Fresh Pond Research Institute | Goldberg M.M.,University of Texas at Austin | And 5 more authors.
Genomics | Year: 2014

In this paper we use eQTL mapping to identify associations between gene dysregulation and single nucleotide polymorphism (SNP) genotypes in glioblastoma multiforme (GBM). A set of 532,954 SNPs was evaluated as predictors of the expression levels of 22,279 expression probes. We identified SNPs associated with fold change in expression level rather than raw expression levels in the tumor. Following adjustment for false discovery rate, the complete set of probes yielded 9257 significant associations (p<. 0.05). We found 18 eQTLs that were missense mutations. Many of the eQTLs in the non-coding regions of a gene, or linked to nearby genes, had large numbers of significant associations (e.g. 321 for RNASE3, 101 for BNC2). Functional enrichment analysis revealed that the expression probes in significant associations were involved in signal transduction, transcription regulation, membrane function, and cell cycle regulation. These results suggest several loci that may serve as hubs in gene regulatory pathways associated with GBM. © 2014 Elsevier Inc.

Cowperthwaite M.C.,NeuroTexas Institute | Cowperthwaite M.C.,University of Texas at Austin | Van Den Hout W.B.,Leiden University | Webb K.M.,NeuroTexas Institute
Journal of Neurosurgery: Spine | Year: 2013

Object. The authors comprehensively studied the recovery of individual patients undergoing treatment for lumbar disc herniation. The primary goal was to gain insight into the variability of individual patient utility scores within a treatment cohort. The secondary goal was to determine how the rates and variability of patient recovery over time, represented by improvement in utility scores, affected long-term patient outcomes. Methods. EuroQol Group-5 Dimension (EQ-5D) scores were obtained at baseline and at 2, 4, 8, 12, 26, 38, and 52 weeks for 93 patients treated under a prolonged conservative care protocol for lumbar disc herniation. Gaussian kernel densities were used to estimate the distribution of utility scores at each time point. Logistic regression and multistate Markov models were used to characterize individual patient improvement over time. Fisher exact tests were used to compare the distribution of EQ-5D domain scores. Results. The distribution of utility scores was bimodal at 1 year and effectively sorted patients into a "higher" utility group (EQ-5D = 1; 43% of cohort) and a "lower" utility group (EQ-5D < 0.86; 57% of cohort). Fisher exact tests revealed that pain/discomfort, mobility, and usual activities significantly differed between the 2 utility groups (p << 0.001). The utility groups emerged at 8 weeks and were stable for the remainder of the treatment period. Using utility scores from 8 weeks, regression models predicted 1-year outcomes with 62% accuracy. Conclusions. This study is the first to comprehensively consider the utility recovery of individual patients within a treatment cohort for lumbar disc herniation. The results suggest that most utility is recovered during the early treatment period. Moreover, the findings suggest that initial improvement is critical to a patient's long-term outcome: patients who do not experience significant initial recovery appear unlikely to do so at a later time under the same treatment protocol. © AANS, 2013.

Shpak M.,NeuroTexas Institute | Shpak M.,University of Texas at Austin | Goldberg M.M.,University of Texas at Austin | Cowperthwaite M.C.,Texas Advanced Computing Center
Cancer Genomics and Proteomics | Year: 2014

Non-motile cilia are thought to be important determinants of the progression of many types of cancers. Our goal was to identify patterns of cilia gene dysregulation in eight cancer types (glioblastoma multiforme, colon adenocarcinoma, breast adenocarcinoma, kidney renal clear cell carcinoma, lung squamous cell carcinoma, lung adenocarcinoma, rectal adenocarcinoma, and ovarian cancer) profiled by The Cancer Genome Atlas. Among these types, 2.5-19.8% of cilia-associated genes were significantly differentially expressed (versus 5.5-32.4% dysregulation across all genes). In four cancer types (breast adenocarcinoma, colon adenocarcinoma, glioblastoma multiforme, and ovarian cancer), cilia genes were on average down-regulated (median fold change from -1.53-0.3), in the other four types, cilia genes were upregulated (fold change=0.86-3.5). Pairwise comparisons between cancer types revealed varying degrees of similarity in the differentially expressed cilia genes, ranging from 7.1% (ovarian cancer and lung squamous cell carcinoma) to 65.8% (ovarian cancer and rectal adenocarcinoma). Hierarchical clustering and principal components analysis of gene expression identified glioblastoma multiforme, colon adenocarcinoma, breast adenocarcinoma; and kidney renal clear cell carcinoma, lung squamous cell carcinoma, lung adenocarcinoma, rectal adenocarcinoma, and ovarian cancer as sub-classes with similar dysregulation patterns. Our study suggests that genes involved in cilia biosynthesis and function are frequently dysregulated in cancer, and may be useful for identifying and classifying cancer types.

Verma N.,University of Texas at Austin | Verma N.,NeuroTexas Institute | Cowperthwaite M.C.,NeuroTexas Institute | Burnett M.G.,NeuroTexas Institute | And 2 more authors.
Neuro-Oncology | Year: 2013

Differentiating treatment-induced necrosis from tumor recurrence is a central challenge in neuro-oncology. These 2 very different outcomes after brain tumor treatment often appear similarly on routine follow-up imaging studies. They may even manifest with similar clinical symptoms, further confounding an already difficult process for physicians attempting to characterize a new contrast-enhancing lesion appearing on a patient's follow-up imaging. Distinguishing treatment necrosis from tumor recurrence is crucial for diagnosis and treatment planning, and therefore, much effort has been put forth to develop noninvasive methods to differentiate between these disparate outcomes. In this article, we review the latest developments and key findings from research studies exploring the efficacy of structural and functional imaging modalities for differentiating treatment necrosis from tumor recurrence. We discuss the possibility of computational approaches to investigate the usefulness of fine-grained imaging characteristics that are difficult to observe through visual inspection of images. We also propose a flexible treatment-planning algorithm that incorporates advanced functional imaging techniques when indicated by the patient's routine follow-up images and clinical condition. © 2013 The Author(s).

Price B.B.,Professional Association | Amini S.B.,George Washington University | Kappeler K.,NeuroTexas Institute
Medicine and Science in Sports and Exercise | Year: 2012

OBJECTIVE: A prospective randomized controlled trial was designed to assess the benefits and possible risks of aerobic exercise during pregnancy, using a fitness regimen based on the 2002 American College of Obstetricians and Gynecologists guidelines for exercise during pregnancy. METHODS: Inactive women were randomized at 12-14 wk gestation to a group that remained sedentary or to a group that performed moderate aerobic exercise 45-60 min, 4 d•wk, through 36 wk gestation. Thirty-one subjects in each group completed the study. RESULTS: Compared with women who remained sedentary, active women improved aerobic fitness (P < 0.05) and muscular strength (P < 0.01), delivered comparable size infants with significantly fewer cesarean deliveries (P < 0.01), and recovered faster postpartum (P < 0.05), at least related to the lower incidence of cesarean section. Active women developed no gestational hypertension (P = 0.16 compared with controls) and reported no injuries related to the exercise regimen. In the active group, there was one premature birth at 33 wk by a woman with a history of premature delivery of twins at 34 wk. There were no differences between groups in the incidence of gestational diabetes, musculoskeletal pains during pregnancy, flexibility on sit-and-reach test, mean length of pregnancy, neonatal Apgar scores, placenta weights, overall length of labor, weight gain during pregnancy, or weight retention postpartum. CONCLUSION: Previously sedentary women who began exercising at 12-14 wk improved fitness and delivery outcomes. Copyright © 2012 by the American College of Sports Medicine.

Wait S.D.,Barrow Neurological Institute | Fox Jr. D.J.,NeuroTexas Institute | Kenny K.J.,Barrow Neurological Institute | Dickman C.A.,Barrow Neurological Institute
Spine | Year: 2012

Study Design: Retrospective review of a prospectively maintained surgical database. Objective: To report the indications, surgical procedures performed, and outcomes from the largest series of thoracoscopically treated herniated thoracic discs (HTDs). We also compared approach-related complications with an unmatched cohort undergoing thoracotomy for HTD. Summary of Background Data: Symptomatic HTDs are rare, and their surgical management is technically challenging. Methods: A prospectively maintained surgical database of all patients undergoing surgery for symptomatic HTDs by the senior author (blinded for review) was reviewed. As needed, the database was supplemented with hospital and clinic charts and telephone conversations with patients. A triportal method of thoracoscopic discectomy was performed in all cases. Results: Between 1994 and 2008, 121 patients underwent 125 thoracoscopic-assisted operations for 139 HTDs. Their mean age at surgery was 46.6 years. Indications for thoracoscopic resection currently include small symptomatic disc, anterior location, nonmorbidly obese patient, favorable chest anatomy, and T4-T11 location. Symptom duration averaged 32 months. Radiculopathy was the most common presentation, followed by myelopathy and pain (radiculopathic or back). The mean hospital stay was 4.8 days. Chest tubes remained in place for a mean of 3.2 days. At a mean follow-up of 2.4 years, myelopathy, radiculopathy, and back pain had resolved or improved at a rate of 91.1%, 97.6%, and 86.5%, respectively. Patients reported worsening in 0%, 1.2%, and 0% of cases, respectively. Most patients (97.4%) would be willing to undergo the operation again. The complication rate was acceptable. Patients undergoing thoracoscopic excision had less approach-related morbidity than an unmatched cohort undergoing excision using thoracotomy. Conclusion: Thoracoscopic-assisted microsurgical resection is a safe, effective, and minimally invasive method of treating symptomatic HTDs in appropriately selected patients. The symptoms of most patients improve or resolve with minimal morbidity.

Kalb S.,Barrow Neurological Institute | Reis M.T.,Barrow Neurological Institute | Cowperthwaite M.C.,NeuroTexas Institute | Fox D.J.,NeuroTexas Institute | And 4 more authors.
World Neurosurgery | Year: 2012

Objective: To evaluate risk factors for the development of dysphagia after anterior cervical surgery. Methods: The records of 249 patients who underwent anterior cervical surgery were reviewed. The presence and severity of dysphagia were assessed with the Dysphagia Disability Index 6 weeks and 3, 6, and 12 months after surgery. Age; sex; ethnicity; cigarette smoking; previous cervical surgeries; reoperation for same pathology; type of procedure, incision, and instrumentation; number and levels involved; side of procedure, length of surgery; and use of postoperative bracing were analyzed. Results: During the first 6 months after surgery, 27 (10.8%) patients developed dysphagia. From these patients the presence of dysphagia at 6 weeks and at 3 and 6 months was 88.8%, 29.6%, and 7.4%, respectively. By 12 months, dysphagia had resolved in all cases. The mean age of patients with dysphagia was 55 years (SD 12.98) and 50 years (SD 12.07) in patients without dysphagia (P = 0.05). Dysphagic patients had an average of 2.2 (SD 1.15) levels operated compared with 1.84 (SD 0.950) in nondysphagic patients (P = 0.05). Patients who developed dysphagia were most often treated at C4-5 (67%) and C5-6 (81%: P < 0.001). Although mean operative time was slightly longer in patients with dysphagia (186 minutes) compared with those without (169 minutes), the difference was not significant. Conclusions: In our patients, the incidence of dysphagia was low, and it had completely resolved at 12 months in all cases. Risk factors for dysphagia were multilevel procedures, involvement of C4-5 and C5-6, and age. © 2012 Elsevier Inc. All rights reserved.

Loading NeuroTexas Institute collaborators
Loading NeuroTexas Institute collaborators