Paraspinous muscle as a predictor of surgical outcome.

BACKGROUND: Objective measures for preoperative risk assessment are needed to inform surgical risk stratification. Previous studies using preoperative imaging have shown that the psoas muscle is a significant predictor of postoperative outcomes. Because psoas measurements are not always available, additional trunk muscles should be identified as alternative measures of risk assessment. Our research assessed the relationship between paraspinous muscle area, psoas muscle area, and surgical outcomes. METHODS: Using the Michigan Surgical Quality Collaborative database, we retrospectively identified 1309 surgical patients who had preoperative abdominal computerized tomography scans within 90 d of operation. Analytic morphomic techniques were used to measure the cross-sectional area of the paraspinous muscle at the T12 vertebral level. The primary outcome was 1-y mortality. Analyses were stratified by sex, and logistic regression was used to assess the relationship between muscle area and postoperative outcome. RESULTS: The measurements of paraspinous muscle area at T12 were normally distributed. There was a strong correlation between paraspinous muscle area at T12 and total psoas area at L4 (r = 0.72, P <0.001). Paraspinous area was significantly associated with 1-y mortality in both females (odds ratio = 0.70 per standard deviation increase in paraspinous area, 95% confidence interval 0.50-0.99, P = 0.046) and males (odds ratio = 0.64, 95% confidence interval 0.47-0.88, P = 0.006). CONCLUSIONS: Paraspinous muscle area correlates with psoas muscle area, and larger paraspinous muscle area is associated with lower mortality rates after surgery. This suggests that the paraspinous muscle may be an alternative to the psoas muscle in the context of objective measures of risk stratification.

Dorsal muscle group area and surgical outcomes in liver transplantation.

INTRODUCTION: Better measures of liver transplant risk stratification are needed. Our previous work noted a strong relationship between psoas muscle area and survival following liver transplantation. The dorsal muscle group is easier to measure, but it is unclear if they are also correlated with surgical outcomes. METHODS: Our study population included liver transplant recipients with a preoperative CT scan. Cross-sectional areas of the dorsal muscle group at the T12 vertebral level were measured. The primary outcomes for this study were one- and five-yr mortality and one-yr complications. The relationship between dorsal muscle group area and post-transplantation outcome was assessed using univariate and multivariate techniques. RESULTS: Dorsal muscle group area measurements were strongly associated with psoas area (r = 0.72; p < 0.001). Postoperative outcome was observed from 325 patients. Multivariate logistic regression revealed dorsal muscle group area to be a significant predictor of one-yr mortality (odds ratio [OR] = 0.53, p = 0.001), five-yr mortality (OR = 0.53, p < 0.001), and one-yr complications (OR = 0.67, p = 0.007). CONCLUSION: Larger dorsal muscle group muscle size is associated with improved post-transplantation outcomes. The muscle is easier to measure and may represent a clinically relevant postoperative risk factor.

Laparoscopic colectomy reduces morbidity and mortality in obese patients.

BACKGROUND: Obesity is a growing epidemic in the US and increases the difficulty of laparoscopic surgery. Randomized, controlled trials of laparoscopic vs. open colectomy have shown equivalence but often exclude obese patients thus not answering whether obese patients may specifically benefit from laparoscopy. We hypothesized that obese patients would benefit from use of laparoscopy for colectomy. METHODS: We used the National Surgical Quality Improvement Program database from 2005 to 2009 and chose elective laparoscopic and open segmental colectomy and ileocecal resections. We compared patients' demographics, comorbidities, and outcomes. We used multivariate models to assess for predictors of complications in obese patients. These models included demographics, comorbidities, and outcomes. RESULTS: 35,998 patients were identified who underwent elective colectomy with primary anastomosis. Forty-four percent of the included cases were laparoscopic and 31 % of patients had a BMI greater than 30 (obese). Obese patients were more likely to have diabetes, hypertension, prior percutaneous coronary intervention, and dyspnea on exertion. We constructed a new variable called any complication that included all complications except 30-day mortality. In our multivariate analysis, laparoscopic approach in obese patients independently decreased the relative risk of superficial (odds ratio (OR) 0.72, 95 % confidence interval (CI) 0.63-0.82) and deep (OR 0.44, CI 0.31-0.61) surgical site infections, intra-abdominal infection (OR 0.61, CI 0.49-0.78), dehiscence (OR 0.50, CI 0.35-0.69), pneumonia (OR 0.60, CI 0.44-0.81), failure to wean from the ventilator (OR 0.64, CI 0.47-0.87), renal failure (OR 0.58, CI 0.35-0.96), urinary tract infection (OR 0.62, CI 0.49-0.79), sepsis (OR 0.53, CI 0.43-0.66), septic shock (OR 0.65, CI 0.47-0.90), any complication (OR 0.61, CI 0.55-0.67) and 30-day mortality (OR 0.56, CI 0.31-0.98). CONCLUSIONS: Due to the significant decrease in the risk of morbidity and mortality, laparoscopic colectomy should be offered to obese patients whenever feasible.

Measuring the complexity of atrial fibrillation electrograms.

INTRODUCTION: Complex fractionated atrial electrograms (CFAE) have been identified as targets for atrial fibrillation (AF) ablation. Robust automatic algorithms to objectively classify these signals would be useful. The aim of this study was to evaluate Shannon's entropy (ShEn) and the Kolmogorov-Smirnov (K-S) test as a measure of signal complexity and to compare these measures with fractional intervals (FI) in distinguishing CFAE from non-CFAE signals. METHODS AND RESULTS: Electrogram recordings of 5 seconds obtained from multiple atrial sites in 13 patients (11 M, 58 +/- 10 years old) undergoing AF ablation were visually examined by 4 independent reviewers. Electrograms were classified as CFAE if they met Nademanee criteria. Agreement of 3 or more reviewers was considered consensus and the resulting classification was used as the gold standard. A total of 297 recordings were examined. Of these, 107 were consensus CFAE, 111 were non-CFAE, and 79 were equivocal or noninterpretable. FIs less than 120 ms identified CFAEs with sensitivity of 87% and specificity of 79%. ShEn, with optimal parameters using receiver-operator characteristic curves, resulted in a sensitivity of 87% and specificity of 81% in identifying CFAE. The K-S test resulted in an optimal sensitivity of 100% and specificity of 95% in classifying uninterpretable electrogram from all other electrograms. CONCLUSIONS: ShEn showed comparable results to FI in distinguishing CFAE from non-CFAE without requiring user input for threshold levels. Thus, measuring electrogram complexity using ShEn may have utility in objectively and automatically identifying CFAE sites for AF ablation.

Assessing compliance with national quality measures to improve colorectal cancer care at the VA.

BACKGROUND: The US Department of Veterans Affairs (VA) Office of Quality and Performance's July 2009 report detailed the quality of VA colorectal cancer (CRC) care on the basis of 10 quality indicators (QIs). Of 21 Veterans Integrated Service Networks (VISNs), the authors' VISN ranked last or near last on more than half of the QIs. The aim of this study was to compare a national-level assessment of performance with an institutional-level clinical review. METHODS: The authors reabstracted all patients seen at surgical hospitals within their VISN during the time period of the Office of Quality and Performance report and reanalyzed their performance on the 10 QIs. A number of quality improvement efforts were also implemented to further boost performance, including the creation of a computerized patient record system CRC order set and quarterly surveillance meetings. RESULTS: After reanalysis of the VISN's QI performance for CRC patients during the time period of the OQP report, the VISN performed 18% better than reported and 2% better than the national average. Since that time, a multidisciplinary CRC committee has implemented quality improvement measures that have further improved QI performance. CONCLUSIONS: There is variability between administrative quality assessments and clinically abstracted data. Care must be taken when analyzing QIs at the national level.