Faculty Bibliography

BACKGROUND:Hand-assisted laparoscopic surgery (HALS) requires a larger incision compared with standard laparoscopic surgery (SLS). Whether this leads to more longterm complications, such as incisional hernia (IH) and small bowel obstruction (SBO), has not been studied to date. This study compares the rates of SBO and IH after HALS and SLS in patients undergoing operations for colon and rectal diseases. STUDY DESIGN/METHODS:From a colorectal database, 536 consecutive patients were identified who underwent bowel resection using HALS (n = 266) and SLS (n = 270) between 2001 to 2006. All medical records were reviewed, and all subjects were contacted by telephone for accurate followup. Statistical analysis was performed using chi-square, Fisher's exact, and Mann-Whitney U tests, where appropriate. RESULTS:Median followup was 27 months (range 1 to 72 months). Overall conversion rate was 2.2% (SLS, n = 4; HALS, n = 8). Median incision size in HALS (75 mm; range 60 to 140 mm) was larger than SLS (45 mm; range 30 to 130 mm; p < 0.01). Despite the larger wound, the incidence of IH was similar between both approaches (HALS, n = 16 [6.0%] versus SLS, n = 13 [4.8%]; p < 0.54). Rate of SBO was also comparable (HALS, n = 11 [4.1%] versus SLS, n = 20 [7.4%]; p = 0.11). Wound infections occurred similarly between both groups (HALS, n = 18 [6.8%]; SLS, n = 13 [4.8%]; p = 0.33). Converted patients had a higher rate of IH compared with nonconverted ones (25% versus 5%; p = 0.02), although the rate of SBO was similar (8.3% versus 5.7%; p = 0.51). CONCLUSIONS:HALS does not lead to more longterm complications of IH and SBO when compared with SLS for resections of the colon and rectum.

The structural effects of cocaine on neural systems mediating cognition and motivation are not well known. By comparing the thickness of neocortical and paralimbic brain regions between cocaine-dependent and matched control subjects, we found that four of 18 a priori regions involved with executive regulation of reward and attention were significantly thinner in addicts. Correlations were significant between thinner prefrontal cortex and reduced keypresses during judgment and decision making of relative preference in addicts, suggesting one basis for restricted behavioral repertoires in drug dependence. Reduced effortful attention performance in addicts also correlated with thinner paralimbic cortices. Some thickness differences in addicts were correlated with cocaine use independent of nicotine and alcohol, but addicts also showed diminished thickness heterogeneity and altered hemispheric thickness asymmetry. These observations suggest that brain structure abnormalities in addicts are related in part to drug use and in part to predisposition toward addiction.

The paper here presented was motivated by a case study involving high-dimensional and high-frequency tidal volume traces measured during induced panic attacks. The focus was to develop a procedure to determine the significance of whether a mean curve dominates another one. The key idea of the suggested method relies on preserving the order in mean while reducing the dimension of the data. The observed data matrix is projected onto a set of lower rank matrices with a positive constraint. A multivariate testing procedure is then applied in the lower dimension. We use simulated data to illustrate the statistical properties of the proposed testing procedure. Results on the case study confirm the preliminary hypothesis of the investigators and provide critical support to their overall goal of creating an experimental model of the clinical panic attack in normal subjects