Faculty Bibliography

The interpretation of images obtained in patients who have recently undergone abdominal or pelvic surgery is challenging, in part because procedures that were previously performed with open surgical techniques are increasingly being performed with minimally invasive (laparoscopic) techniques. Thus, it is important to be familiar with the normal approach used for laparoscopic surgeries. The authors describe the indications for various laparoscopic surgical procedures (eg, cholecystectomy, appendectomy, hernia repair) as well as normal postoperative findings. For example, port site hernias are more commonly encountered in patients with trocar sites greater than 10 mm and occur at classic entry sites (eg, the periumbilical region). Similarly, preperitoneal air can be encountered postoperatively, often secondary to trocar dislodgement during difficult entry or positioning. In addition, intraperitoneal placement of mesh during commonly performed ventral or incisional hernia repairs typically leads to postoperative seroma formation. Familiarity with normal findings after commonly performed laparoscopic surgical procedures in the abdomen and pelvis allows accurate diagnosis of common complications and avoidance of diagnostic pitfalls. (c) RSNA, 2014.

INTRODUCTION: Abnormality in distal lung function may occur in obesity due to reduction in resting lung volume; however, airway inflammation, vascular congestion and/or concomitant intrinsic airway disease may also be present. The goal of this study is to 1) describe the phenotype of lung function in obese subjects utilizing spirometry, plethysmography and oscillometry; and 2) evaluate residual abnormality when the effect of mass loading is removed by voluntary elevation of end expiratory lung volume (EELV) to predicted FRC. METHODS: 100 non-smoking obese subjects without cardio-pulmonary disease and with normal airflow on spirometry underwent impulse oscillometry (IOS) at baseline and at the elevated EELV. RESULTS: FRC and ERV were reduced (44+/-22, 62+/-14% predicted) with normal RV/TLC (29+/-9%). IOS demonstrated elevated resistance at 20 Hz (R20, 4.65+/-1.07 cmH2O/L/s); however, specific conductance was normal (0.14+/-0.04). Resistance at 5-20 Hz (R5-20, 1.86+/-1.11 cmH2O/L/s) and reactance at 5 Hz (X5, -2.70+/-1.44 cmH2O/L/s) were abnormal. During elevation of EELV, IOS abnormalities reversed to or towards normal. Residual abnormality in R5-20 was observed in some subjects despite elevation of EELV (1.16+/-0.8 cmH2O/L/s). R5-20 responded to bronchodilator at baseline but not during elevation of EELV. CONCLUSIONS: This study describes the phenotype of lung dysfunction in obesity as reduction in FRC with airway narrowing, distal respiratory dysfunction and bronchodilator responsiveness. When R5-20 normalized during voluntary inflation, mass loading was considered the predominant mechanism. In contrast, when residual abnormality in R5-20 was demonstrable despite return of EELV to predicted FRC, mechanisms for airway dysfunction in addition to mass loading could be invoked.

BACKGROUND: Genetic factors likely play a role in obesity and the outcomes after bariatric surgery. Single nucleotide polymorphisms in or near the insulin-induced gene 2 (INSIG-2), fat mass and obesity-associated gene (FTO), melanocortin 4 receptor gene (MC4R), and proprotein convertase subtilisn/kexin type 1 gene (PCSK-1) have been associated with class III obesity in whites. Minimal data are available regarding the genetic susceptibility to obesity in class III obese nonwhites, especially Hispanics. Our objective was to perform a comparative analysis of 4 common genetic variants (INSIG-2, FTO, MC4R, and PCSK-1) associated with obesity in a diverse population of bariatric surgery patients to determine whether a difference exists by ethnicity (white versus Hispanic). The setting of the study was 2 university hospitals in the United States. METHODS: Bariatric surgery patients from 2 different institutions were enrolled prospectively, and genotyping was performed. Differences in the distribution of INSIG-2, FTO, MC4R, and PCSK-1 single nucleotide polymorphisms among the different ethnicities (whites and Hispanics) were compared using an additive model (0, 1, or 2 risk alleles). A propensity-matched analysis was used to account for cohort differences. RESULTS: A total of 1276 bariatric patients were genotyped for the INSIG-2, FTO, MC4R, and PCSK-1 obesity single nucleotide polymorphisms. Statistically significant differences in FTO, INSIG-2, MC4R, and PCSK-1 were seen using an additive model. FTO, PCSK-1, and MC4R (test for trend) remained significantly different in the propensity analysis. CONCLUSION: Significant differences in the frequencies of several common obesity susceptibility variants in or near FTO, PCSK-1, and MC4R were found in white and Hispanic patients with class III obesity undergoing bariatric surgery. Larger studies in more class III obese Hispanics of different nationalities are needed.

OBJECTIVE:: To conduct a systematic review to identify surgical strategies that may decrease leak after laparoscopic sleeve gastrectomy (LSG). BACKGROUND:: LSG is growing in popularity as a primary bariatric procedure. Technical aspects of LSG including bougie size remain controversial. METHODS:: Our systematic review yielded 112 studies encompassing 9991 LSG patients. A general estimating equation (GEE) model was used to calculate the odds ratio (OR) for leak based on bougie size, distance from the pylorus, and use of buttressing on the staple line. Baseline characteristics, including age and body mass index (BMI), were included. A linear repeated measures regression model compared excess weight loss (%EWL) between bougie sizes. RESULTS:: A total of 198 leaks in 8922 patients (2.2%) were identified. The GEE model revealed that the risk of leak decreased with bougie >/=40 Fr (OR = 0.53, 95% CI = [0.37-0.77]; P = 0.0009). Buttressing did not impact leak. There was no difference in %EWL between bougie <40 Fr and bougie >/=40 Fr up to 36 months (mean: 70.1% EWL; P = 0.273). Distance from the pylorus did not affect leak or %EWL. CONCLUSIONS:: Utilizing bougie >/=40 Fr may decrease leak without impacting %EWL up to 3 years. Distance from the pylorus does not impact leak or weight loss. Buttressing does not seem to impact leak; however, if surgeons desire to buttress, bioabsorbable material is the most common type used. Longer-term studies are needed to definitively determine the effect of bougie size on weight loss after LSG.

BACKGROUND: Previous studies have shown accelerated gastric emptying after sleeve gastrectomy. This study aimed to determine whether a correlation exists between immediate postoperative gastroduodenal transit time and weight loss after laparoscopic sleeve gastrectomy (LSG). Specifically, correlation tests were conducted to determine whether more rapid transit after LSG correlated with increased weight loss. METHODS: Data were collected from an institutional review board-approved electronic registry. All LSGs were performed over a 40-Fr bougie, starting 5 to 7 cm proximal to the pylorus. Gastroduodenal transit time (antrum to duodenum) was calculated from a postoperative day 1 esophagram. Pearson's correlation coefficient was used for statistical analysis. RESULTS: The analysis included 62 consecutive LSG patients. The mean gastroduodenal transit time was 12.3 +/- 19.8 s. Almost all the patients (99 %) had a transit time less than 60 s. The mean percentage of excess weight loss (%EWL) was 23.8 +/- 9.8 % at 3 months, 37.9 +/- 11.8 % at 6 months, and 52.2 +/- 10.8 % at 12 months. No correlation was found between gastroduodenal transit time and %EWL at 3, 6, or 12 months. CONCLUSION: No correlation was found between gastroduodenal transit time and weight loss after LSG.