Postoperative Outcomes and Resource Utilization Following Open vs Endoscopic Far Lateral Lumbar Discectomy

Background: Operative approaches for far lateral disc herniation (FLDH) repair may be classified as open or minimally invasive. The present study aims to compare postoperative outcomes and resource utilization between patients undergoing open and endoscopic (one such minimally invasive approach) FLDH surgeries. Methods: A total of 144 consecutive adult patients undergoing FLDH repair at a single, university health system over an 8-year period (2013-2020) were retrospectively reviewed. Patients were divided into 2 cohorts: open (n = 92) and endoscopic (n = 52). Logistic regression was performed to evaluate the impact of procedural type on postoperative outcomes, and resource utilization metrics were compared between cohorts using & chi;2 test (for categorical variables) or t test (for continuous variables). Primary postsurgical outcomes included readmissions, reoperations, emergency department visits, and neurosurgery outpatient office visits within 90 days of the index operation. Primary resource utilization outcomes included total direct cost of the procedure and length of stay. Secondary measures included discharge disposition, operative length, and duration of follow- up. Results: No differences were observed in adverse postoperative events. Patients undergoing open FLDH surgery were more likely to attend outpatient visits within 30 days (P = 0.016). Although direct operating room cost was lower (P \u3c 0.001) for open procedures, length of hospital stay was longer (P \u3c 0.001). Patients undergoing open surgery also demonstrated less favorable discharge dispositions, longer operative length, and greater duration of follow- up. Conclusions: While both procedure types represent viable options for FLDH, endoscopic surgeries appear to achieve comparable clinical outcomes with decreased perioperative resource utilization. Clinical Relevance: The present study suggests that endoscopic FLDH repairs do not lead to inferior outcomes but may decrease utilization of perioperative resources. Level of Evidence: 3

Outcomes Following Discectomy for Far Lateral Disc Herniation Are Not Predicted by Obstructive Sleep Apnea

Introduction: Previous studies have demonstrated that obstructive sleep apnea (OSA) is associated with adverse postoperative outcomes, but few studies have examined OSA in a purely spine surgery population. This study investigates the association of the STOP-Bang questionnaire, a screening tool for undiagnosed OSA, with adverse events following discectomy for far lateral disc herniation (FLDH). Methods: All adult patients (n = 144) who underwent FLDH surgery at a single, multihospital, academic medical center (2013-2020) were retrospectively enrolled. Univariate logistic regression was performed to evaluate the relationship between risk of OSA (low- or high-risk) according to STOP-Bang score and postsurgical outcomes, including unplanned hospital readmissions, ED visits, and reoperations. Results: Ninety-two patients underwent open FLDH surgery, while 52 underwent endoscopic procedures. High risk of OSA according to STOP-Bang score did not predict risk of readmission, ED visit, outpatient office visit, or reoperation of any kind within either 30 days or 30-90 days of surgery. High risk of OSA also did not predict risk of reoperation of any kind or repeat neurosurgical intervention within 30 days or 90 days of the index admission (either during the same admission or after discharge). Conclusion: The STOP-Bang questionnaire is not a reliable tool for predicting post-operative morbidity and mortality for FLDH patients undergoing discectomy. Additional studies are needed to assess the impact of OSA on morbidity and mortality in other spine surgery populations

Movement Preparation and Bilateral Modulation of Beta Activity in Aging and Parkinson’s Disease

In previous studies of young subjects performing a reaction-time reaching task, we found that faster reaction times are associated with increased suppression of beta power over primary sensorimotor areas just before target presentation. Here we ascertain whether such beta decrease similarly occurs in normally aging subjects and also in patients with Parkinson’s disease (PD), where deficits in movement execution and abnormalities of beta power are usually present. We found that in both groups, beta power decreased during the motor task in the electrodes over the two primary sensorimotor areas. However, before target presentation, beta decreases in PD were significantly smaller over the right than over the left areas, while they were symmetrical in controls. In both groups, functional connectivity between the two regions, measured with imaginary coherence, increased before the target appearance; however, in PD, it decreased immediately after, while in controls, it remained elevated throughout motor planning. As in previous studies with young subjects, the degree of beta power before target appearance correlated with reaction time. The values of coherence during motor planning, instead, correlated with movement time, peak velocity and acceleration. We conclude that planning of prompt and fast movements partially depends on coordinated beta activity of both sensorimotor areas, already at the time of target presentation. The delayed onset of beta decreases over the right region observed in PD is possibly related to a decreased functional connectivity between the two areas, and this might account for deficits in force programming, movement duration and velocity modulation

Neural Activations during Visual Sequence Learning Leave a Trace in Post-Training Spontaneous EEG

Recent EEG studies have shown that implicit learning involving specific cortical circuits results in an enduring local trace manifested as local changes in spectral power. Here we used a well characterized visual sequence learning task and high density-(hd-)EEG recording to determine whether also declarative learning leaves a post-task, local change in the resting state oscillatory activity in the areas involved in the learning process. Thus, we recorded hd-EEG in normal subjects before, during and after the acquisition of the order of a fixed spatial target sequence (VSEQ) and during the presentation of targets in random order (VRAN). We first determined the temporal evolution of spectral changes during VSEQ and compared it to VRAN. We found significant differences in the alpha and theta bands in three main scalp regions, a right occipito-parietal (ROP), an anterior-frontal (AFr), and a right frontal (RFr) area. The changes in frontal theta power during VSEQ were positively correlated with the learning rate. Further, post-learning EEG recordings during resting state revealed a significant increase in alpha power in ROP relative to a pre-learning baseline. We conclude that declarative learning is associated with alpha and theta changes in frontal and posterior regions that occur during the task, and with an increase of alpha power in the occipito-parietal region after the task. These post-task changes may represent a trace of learning and a hallmark of use-dependent plasticity

Cavernous Malformation Surgery in the United States: Validation of a Novel International Classification of Disease, 10th Edition, Clinical Modification Code Search Algorithm and Volume-Driven Surgical Outcomes

OBJECTIVE: The surgical decision-making process for cavernous malformation (CM) must weigh the risks of surgery against the burden of patient symptoms/hemorrhage and anticipated natural history. Here, we sought to internally validate an International Classification of Disease (ICD)-10 search algorithm for CM surgery to use to analyze a nationwide administrative database. METHODS: Institutional records were accessed to test the validity of a novel ICD-10 search algorithm for CM surgery. The algorithm identified patients with positive predictive value (92%), specificity (100%), and sensitivity of 55%. The algorithm was applied to extract our target population from the Nationwide Readmissions Database. Univariate and multivariable analyses were used to identify factors influencing patient outcomes. RESULTS: We identified 1235 operations for supratentorial (87%) or infratentorial (13%) CM surgery from the Nationwide Readmissions Database (2016-2017). The overall rate of adverse disposition and 30-day readmission were 19.7% and 7.5%, respectively. The rate of adverse disposition was significantly higher for infratentorial (vs. supratentorial cases) (34.3% vs. 17.6%, P = 0.001) and brainstem (vs. cerebellar) cases (55% vs. 28%, P = 0.03). Hospital case-volume percentile was associated with decreasing rates of adverse disposition (1-74th: 22%, 75th: 16%, 90th: 13%, 95th: 7%). Treatment at HVCs was also associated with shorter average length of stay (4.6 vs. 7.3 days, P \u3c 0.001) without significant changes to average cost of hospitalization (P = 0.60). CONCLUSIONS: Our ICD-10 coding algorithm reliably identifies CM surgery with minimal false positives. Outcomes were influenced by patient age, clinical presentation, location of CM, and experience of institution. Centralization of care may improve outcomes and warrants further investigation

Temporal Evolution of Oscillatory Activity Predicts Performance in a Choice-Reaction Time Reaching Task

In this study, we characterized the patterns and timing of cortical activation of visually guided movements in a task with critical temporal demands. In particular, we investigated the neural correlates of motor planning and on-line adjustments of reaching movements in a choice-reaction time task. High-density electroencephalograohy (EEG, 256 electrodes) was recorded in 13 subjects performing reaching movements. The topography of the movement-related spectral perturbation was established across five 250-ms temporal windows (from prestimulus to postmovement) and five frequency bands (from theta to beta). Nine regions of interest were then identified on the scalp, and their activity was correlated with specific behavioral outcomes reflecting motor planning and on-line adjustments. Phase coherence analysis was performed between selected sites. We found that motor planning and on-line adjustments share similar topography in a fronto-parietal network, involving mostly low frequency bands. In addition, activities in the high and low frequency ranges have differential function in the modulation of attention with the former reflecting the prestimulus, top-down processes needed to promote timely responses, and the latter the planning and control of sensory-motor processes

Beta power changes.

<p>A and B. Averages of the time courses of beta power changes in dB over the Left (solid line) and Right (dotted line) ROIs in controls (A) and patients with PD (B). The data were anchored at the time of target appearance (0 ms, filled arrows and thin solid lines). The empty arrows and thin dotted lines indicate the average time of movement onset (i.e., reaction time, RT) for each group. Negative time values on the X-axis represent the pre-target interval and from 0 to the empty arrow the reaction time period. Significant differences (p<0.05) between the two ROIs are indicated in the bottom part of each plot. C. Average of the normalized imaginary coherence in controls (thin line) and patients with PD (thick line). As in A and B, the data were anchored at the time of target appearance (0 ms, filled arrows). The empty arrows and vertical dotted lines indicate the average RT for each group. Significant differences between the two groups (p<0.05, nonparametric unpaired t-test with Bonferroni correction) are indicated in the bottom part of the plot. D. Individual differences of beta power between the left and the right ROIs averaged over the 200 ms time-interval before target appearance are plotted for the PD patients (on the left) and the controls (on the right). The thick horizontal lines represent the average for each group. The circles and the squares in the PD group represent patients with clinically predominant right and left motor impairment, respectively. </p

Gamma Knife radiosurgery for trigeminal neuralgia provides greater pain relief at higher dose rates

In Gamma Knife (GK) radiosurgery, dose rate decreases during the life cycle of its radiation source, extending treatment times. Prolonged treatments influence the amount of sublethal radiation injury that is repaired during exposure, and is associated with decreased biologically-equivalent dose (BED). We assessed the impact of treatment times on clinical outcomes following GK of the trigeminal nerve - a rare clinical model to isolate the effects of treatment times. This is a retrospective analysis of 192 patients with facial pain treated across three source exchanges. All patients were treated to 80 Gy with a single isocenter. Treatment time was analyzed in terms of patient anatomy-specific dose rate, as well as BED calculated from individual patient beam-on times. An outcome tool measuring pain in three distinct domains (pain intensity, interference with general and oro-facial activities of daily living), was administered before and after intervention. Multivariate linear regression was performed with dose rate/BED, brainstem dose, sex, age, diagnosis, and prior intervention as predictors. BED was an independent predictor of the degree of improvement in all three dimensions of pain severity. A decrease in dose rate by 1.5 Gy/min corresponded to 31.8% less improvement in the overall severity of pain. Post-radiosurgery incidence of facial numbness was increased for BEDs in the highest quartile. Treatment time is an independent predictor of pain outcomes, suggesting that prescription dose should be customized to ensure iso-effective treatments, while accounting for the possible increase in adverse effects at the highest BEDs