Wallace-Kettering Neuroscience Institute

IntroductionOblique lumbar interbody fusion (OLIF) is a newer procedure that avoids the psoas and lumbosacral plexus due to its oblique trajectory into the retroperitoneal space. While early experience with OLIF is reassuring, the longer-term clinical efficacy has not been well established. The purpose of this study was to describe two-year clinical outcomes with OLIF performed by a single surgeon during the learning curve without the aid of the neuromonitoring.Materials and methodsChart review was performed for the consecutive patients who underwent OLIF by a single surgeon. Back pain severity on a visual analog scale (VAS) and Oswestry Disability Index (ODI) were collected preoperatively and postoperatively at six weeks, three months, six months, one year and two years.ResultsA total of 21 patients (38 levels) were included in this study. The indications for surgery were degenerative disc disease (n=10, 47.6%), spondylolisthesis (n=9, 42.9%) and spinal stenosis (n=6, 28.6%). The median operating room time was 351 minutes (interquartile range (IQR): 279-406 minutes), blood loss was 40 ml (IQR: 30-150 ml), and hospital stay was 2.0 days (IQR: 1.0-3.5 days). The complication rate was 9.5%, both venous injuries. There were no other perioperative complications. Back pain severity decreased by 70%, on average, over two years (p <0.001). A total of 17 (81%) patients reported at least a two-point decrease from the baseline. The ODI scores decreased by 55%, on average, over two years (p <0.001), with 16 (76%) patients reporting at least a 15-point decrease from the baseline. Over two years, no symptomatic pseudarthrosis, hardware failure, reoperations, or additional complications were reported.ConclusionsThe oblique lateral interbody fusion performed without the intraoperative neuromonitoring was safe and clinically efficacious for up to two years. The complication rate in this cohort is similar to other published OLIF series and appears acceptable when compared to the lateral lumbar interbody fusion (LLIF) and the anterior lumbar interbody fusion (ALIF). No motor or sensory deficits were observed in this study, supporting the premise that the neuromonitoring is unnecessary in OLIF.

Executive dysfunction predicts functional recovery post-stroke. However, traditional neuropsychological tests have limitations with this population due to required verbal response, complex motor response, and lengthy administration time. This study examined the ecological validity and performance characteristics of a relatively new measure of executive function, the Brixton Spatial Anticipation Test, which does not place the aforementioned demands on these patients. A total of 57 ischemic stroke patients with frontal lobe and subcortical lesions were administered the Brixton, on average 2 weeks post-stroke, during inpatient rehabilitation and assessed using the Functional Independence Measure (FIM) upon discharge. Brixton performance was significantly correlated with the FIM Total and FIM Cognitive Subtotal at discharge but unrelated to FIM Motor Subtotal. After controlling for global ability measured by the RBANS, Brixton performance accounted for additional variance in predicting FIM Total score at discharge. Interestingly, patients with subcortical strokes in the thalamus and basal ganglia performed significantly worse than patients with strokes in the frontal cortex on the Brixton, supporting the role of subcortical structures in the frontal lobe circuitry and executive function. Based on the present findings, the Brixton is a sensitive measure conducive to the stroke population and has strong ecological validity for identifying cognitive functional outcomes post-stroke.

Psychiatric comorbidities are common among patients with schizophrenia. Substance abuse comorbidity predominates. Anxiety and depressive symptoms are also very common throughout the course of illness, with an estimated prevalence of 15% for panic disorder, 29% for posttraumatic stress disorder, and 23% for obsessive-compulsive disorder. It is estimated that comorbid depression occurs in 50% of patients, and perhaps (conservatively) 47% of patients also have a lifetime diagnosis of comorbid substance abuse. This article chronicles these associations, examining whether these comorbidities are "more than chance" and might represent (distinct) phenotypes of schizophrenia. Among the anxiety disorders, the evidence at present is most abundant for an association with obsessive-compulsive disorder. Additional studies in newly diagnosed antipsychotic-naive patients and their first-degree relatives and searches for genetic and environmental risk factors are needed to replicate preliminary findings and further investigate these associations.

The Multiple Sleep Latency Test (MSLT) and the Maintenance of Wakefulness Test (MWT) are two commonly used laboratory-based objective tests to measure sleepiness and alertness, respectively. Data suggest both are extremely sensitive tests when measuring the effects of sleep deprivation within subjects, but are less sensitive for confirming sleepiness and response to treatment in groups of patients with different sleep disorders. Inconsistent and even sometimes paradoxical test results may be partly explained by data that show the MSLT and MWT are not selectively sensitive to either sleepiness or alertness, but sensitive to both the sleep and the arousal systems. Sleep latencies seen on both the MSLT and MWT are affected to varying degrees by a myriad of internal and external influences that can alter what we would prefer each test to show. If we continue to use these tests to measure sleepiness or alertness in patients with different sleep disorders, we need to understand more about the nature and impact of different sources of internal and external arousal so that we can better control the test environment. Improved understanding of the determinants of sleep onset is essential because excessive sleepiness has important consequences for both individuals and society.

The purpose of this study was to determine how long the effects of a brief period of physiological arousal persisted using repeated sleep latency testing and measurement of heart rate. Thirteen normal sleeping young adults spent two non-consecutive nights and the following days in the laboratory. On each day, subjects had five sleep latency measurements - at 09:00, 09:30, 10:00, 10:30, and 11:00 hours. The 09:00 test was a premanipulation baseline. Following this nap, subjects either walked for 5 min (on one day) or rested in bed for 10 min (on another day) prior to the 09:30 hours sleep latency test. Significant increases in sleep latency were found at 09:30, 10:00, and 11:00 hours following the single 5-min walk as compared with resting in bed (mean sleep latency after the walk was 11.7 min compared with 7.1 min for the resting condition). Heart rate was significantly higher throughout all of the postmanipulation naps following the walk. The elevated sleep latency is probably secondary to the changes in underlying physiological arousal as measured in this study by heart rate.

Because automated methods that segment tomographic (medical) images often involve errors, editing tools that can rapidly correct the errors are needed. The editing tools presented in this paper may be considered a part of a postprocessing operation that evaluates the accuracy of an automated segmentation and refines the errors.

Ska and colleagues (1990) reported that patients with possible or probable Alzheimer's Disease (AD) make characteristic errors on a measure of line orientation judgment. We examined errors of line orientation judgment in a sample of 31 patients with probable AD, 28 patients with idiopathic Parkinson's disease (PD), and 24 normal elderly controls (NC). Results indicated that, in comparison to NC participants, some error types were made more frequently by patients with PD and patients with AD. No error type, however, was specific to AD alone. In contrast, PD patients were more likely than AD or NC participants to make a specific error in oblique line judgment. This finding is discussed in the context of visuospatial analysis and selective attention in patients with PD.