Perioperative Outcomes and Fellow Experience During Minimally Invasive Bariatric Surgery Training

Rouzbeh Mostaedi, MD, Mohamed R Ali, MD. University of California, Davis


Reports have identified the learning curve for minimally invasive bariatric surgery (MIBS) and compared the outcomes from “fellow cases” to outcomes from “attending cases.” While such comparisons have generally been favorable, we have observed that the operative performance of MIBS fellows often improves dramatically over the course of training. Thus, we sought to determine whether patient outcomes would be affected by the level of experience of the fellow during training.

Methods and Procedures

Clinical, operative, and outcome data were reviewed for 984 consecutive primary MIBS cases [Roux-en-Y gastric bypass (RYGB), vertical sleeve gastrectomy (VSG), adjustable gastric banding (AGB)] performed at a single academic institution over 6 years. These cases were performed by the fellow with attending assistance. Clinical (demographic, anthropomorphic, comorbidity), operative, and outcomes data were compared between cases performed during the first half of the fellowship year and cases performed during the second half.


Procedures were categorized by case type and time of year: 479 MIBS cases performed during the first six months (RYGB-A=365, VSG-A=69, AGB-A=45) and 505 MIBS cases performed during the second six months (RYGB-B=338, VSG-B=108, AGB-B=59) of training. RYGB-A and RYGB-B were comparable in age (44.8±11.6 years vs 44.9±8.1 years, p=0.91), gender distribution (80.0% women vs 79.3% women, p=0.89), body mass index (BMI) (47.3±8.1 kg/m2 vs 46.9±8.1 kg/m2, p=0.54), estimated blood loss (EBL) (72.2±70.4 ml vs 74.5±107.7 ml, p=0.74), and hospital length of stay (LOS) (48.5±48.8 hours vs 44.3±28.8 hours, p=0.11). Patients in VSG-B group were older (47.4±9.6 years vs 44.4±10.0 years, p<0.05) than VSG-A group, but there were no differences in gender distribution (79.7% women vs 80.6% women, p=0.99), BMI (44.7±7.9 kg/m2 vs 43.2±6.5 kg/m2, p=0.32), EBL (42.7±53.0 ml vs 47.7±86.7 ml, p=0.63), or LOS (52.2±31.9 hours vs 50.7±31.0 hours, p=0.76). No statistical differences were identified between AGB-A and AGB-B in age, gender, EBL, or LOS. However, BMI was higher in the second half of the year (AGB-B) (47.1±8.9 kg/m2 vs 43.9±6.3 kg/m2, p<0.05). For all comparisons, American Society of Anesthesia (ASA) classification, history of prior abdominopelvic surgery, and severity of obesity-related comorbidities (diabetes mellitus, hypertension, cardiovascular disease, and obstructive sleep apnea) were not significantly different between the respective groups.

Operative time did not change significantly for VSG (116.7±39.4 minutes vs 110.9±41.3 minutes, p=0.35) or AGB (113.2±44.1 minutes vs 98.2±39.7 minutes, p=0.07) but was significantly improved for RYGB (184.2±45.5 minutes vs 159.3±52.4 minutes, p<0.0001). Overall, major morbidity and mortality (M&M) were low (venous thromboembolism=0.51%, splenic injury=0.30%, transfusion=2.13%, gastrointestinal hemorrhage=0.10%, wound infection=0.30%, marginal ulcer=1.34%, internal hernia=0.16%, reoperation=0.51%, mortality=0.10%). M&M rates did not significantly differ from the first to second half of the year (4.13% vs 4.12%, p=0.996).


VSG and AGB can be performed with technical adeptness early in fellowship. RYGB is technically more complex, and fellows will improve operative efficiency during the latter part of training. Regardless, surgical outcomes are not adversely affected by relative inexperience of MIBS fellows early in the fellowship year in patients of similar surgical complexity, acuity, and disease severity.

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