Faculty Bibliography

BACKGROUND:RYGB consists of the Roux limb (RL), the biliopancreatic limb (BPL), and the common channel (CC). There is no consensus on the optimal limb lengths. METHODS:Using a mouse model of RYGB, 30 diet-induced obese mice were divided into two groups with varying BPL and CC lengths: a standard BPL with a long CC (RYGB S) and a long BPL with a short CC (RYGB L). Additionally, 9 age-matched, lean control mice (LC) were also included in this study. RESULTS:RYGB S had limb lengths of RL = 17%, BPL = 24%, and CC = 59%. RYGB L had limb lengths of RL = 17%, BPL = 32%, and CC = 51%. RYGB S and RYGB L had 67% and 40% survival, respectively. Mortality in RYGB L included more instances where the cause of death was not apparent. RYGB L demonstrated greater weight loss, lower energy expenditure, and lower heart mass as compared to RYGB S. Both RYGB groups had lower epidydimal fat mass, spleen mass, and bone mineral density compared to LC. RYGB L had a lower heart mass than RYGB S and LC. While the relative abundance of Eubacterium was lower in RYGB L than in RYGB S, no other gut microbiota differences were observed. CONCLUSIONS:A longer BPL with a shorter CC induces greater weight loss but may lead to adverse effects, including lower heart mass, reduced bone density, and deaths with unclear causes.

BACKGROUND:Postoperative internal hernias after Roux-en-Y gastric bypass (RYGB) have an incidence of 2%-9% and are a surgical emergency. Evidence on factors associated with length of stay (LOS) after emergent internal hernia reduction in RYGB patients is limited. METHODS:This is a retrospective review of patients who underwent internal hernia reduction after RYGB at our tertiary care center over a 5 year period from 2015 to 2020. Demographics, comorbidities, and intra- and postoperative hospital course were collected. Univariate and multivariate linear regressions were used to investigate factors associated with LOS. RESULTS:< .001) were independent risk factors for increased LOS. CONCLUSION/CONCLUSIONS:The most common location of IH after RYGB is Petersen's defect, followed by jejuno-jejunal mesenteric defect. LOS was significantly associated with male sex, exploratory laparotomy, and resection of small bowel.

PURPOSE/OBJECTIVE:Roux-en-Y gastric bypass (RYGB) leads to the improvement of many obesity-associated conditions. The degree to which post-operative macronutrient composition contributes to metabolic improvement after RYGB is understudied. METHODS:A mouse model of RYGB was used to examine the effects of diet on the post-operative outcomes of RYGB. Obese mice underwent either Sham or RYGB surgery and were administered either chow or HFD and then monitored for an additional 8 weeks. RESULTS:After RYGB, reductions to body weight, fat mass, and lean mass were similar regardless of diet. RYGB and HFD were independently detrimental to bone mineral density and plasma vitamin D levels. Independent of surgery, HFD accelerated hematopoietic stem and progenitor cell proliferation and differentiation and exhibited greater myeloid lineage commitment. Independent of diet, systemic iron deficiency was present after RYGB. In both Sham and RYGB groups, HFD increased energy expenditure. RYGB increased fecal energy loss, and HFD after RYGB increased fecal lipid content. RYGB lowered fasting glucose and liver glycogen levels but HFD had an opposing effect. Indices of insulin sensitivity improved independent of diet. HFD impaired improvements to dyslipidemia, NAFLD, and fibrosis. CONCLUSION/CONCLUSIONS:Post-operative diet plays a significant role in determining the degree to which RYGB reverses obesity-induced metabolic abnormalities such as hyperglycemia, dyslipidemia, and NAFLD. Diet composition may be targeted in order to assist in the treatment of post-RYGB bone mineral density loss and vitamin D deficiency as well as to reverse myeloid lineage commitment. HFD after RYGB continues to pose a significant multidimensional health risk.

OBJECTIVE:The objective of this study was to examine the use and outcomes of perioperative anticoagulation (AC) in obese patients with a known history of venous thromboembolism event (VTE). METHOD/METHODS:A retrospective review of a prospective database for patients with a VTE history undergoing bariatric and general surgery at a single center (1/2008-12/2017) was performed. Factors assessed included demographics, surgical details, and outcomes. RESULTS:Sixty-five patients underwent 76 procedures: 46 females (71%); mean age 51 years (range 26-73), mean weight 284 pounds (range 110-558), mean body mass index 45 (range 19-87). Comorbidities include hypertension (60%), gastroesophageal reflux disease (54%), osteoarthritis (49%), obstructive sleep apnea (45%), and diabetes (37%). Operations: 22 general surgeries (29%), 20 sleeve gastrectomies (26%), 12 revisions/conversions (16%), 12 Roux-en-Y gastric bypasses (16%), and 10 gastric bands (13%). Modalities: 67% laparoscopic, 28% robotic, and 5% open. Twenty-two patients (34%) had a pre-operative inferior vena cava filter placed with no complications. The mean length of stay was 4.4 days (range 1-31). Complications: seven 30-day readmissions (9%), one 30-day reoperation (1%), and two 90-day VTEs (3%). Thirty-day readmissions: four for inability to tolerate PO, two for small bowel obstruction, and one for symptomatic anastomotic ulcer. CONCLUSIONS:In our patients, post-operative AC could be started without an increased risk of bleeding in patients with a history of VTE undergoing bariatric surgery.

BACKGROUND:Evidence shows that 14.2% of opioid-naive patients have long-term opioid dependence after bariatric surgery. Enhanced recovery after surgery (ERAS) protocols are widely used in bariatric surgery, while bariatric surgery targeting opioid prescriptions (BSTOP) protocols were recently introduced. We will investigate the combined impact of ERAS and BSTOP protocols after bariatric surgery. METHODS:We conducted a retrospective review for patients who underwent either a sleeve gastrectomy or Roux-en-Y gastric bypass at a tertiary care center. Pre-intervention and post-intervention data were compared. Primary outcomes were length of stay (LOS), 30-day readmission, 30-day complications, and discharge on opioids. Multivariate Poisson regression with robust standard error was used to analyze LOS. RESULTS:There was no significant difference in 30-day emergency room visits (3.3% vs. 4.0%; p value = 0.631), 30-day readmission (4.4% vs. 5.4%; p value = 0.577) or 30-day complication rate (4.2% vs. 6.4%; p value = 0.199). LOS was significantly lower in the post-intervention group; mean (interquartile range) 2 (1-2) days vs. 1 (1-2) day, p value < 0.001. On multivariate analysis, the post-intervention group had 0.74 (95% confidence interval 0.65-0.85; p value < 0.001) times lower LOS as compared to pre-intervention group. Patients with DM had a significantly longer LOS (relative risk: 1.22; p = 0.018). No other covariates were associated with LOS (p value < 0.05 for all). BSTOP analysis found a significant difference between the two groups. Discharge on opioids decreased from 40.6% pre-intervention to 7.1% post-intervention. CONCLUSION:ERAS and BSTOP protocols reduced length of stay and opioid need at discharge without an increase in complication or readmission rates.

An aortocaval fistula, a rare abnormal vascular communication between the aorta and inferior vena cava, is most commonly associated with abdominal aortic aneurysms (AAAs). Other factors leading to aortocaval fistula formation include atherosclerosis, collagen vascular diseases, vasculitis, hematogenous infections, prior spinal surgery, malignancy and radiation exposure. In rare instances, aortocaval fistulas may be discovered incidentally on abdominal imaging. We report an unusual case of an incidental aortocaval fistula in a 93-year-old male patient with an unruptured AAA, presenting with shortness of breath, malaise and lethargy. The patient had no other obvious risk factors for aortocaval fistula formation. Multidetector computed tomography angiography helped identify the fistula, and the patient was eventually transferred to hospice for comfort measures. This case highlights the importance of detailed imaging and preoperative planning in managing aortocaval fistulas and associated AAAs.

Solitary fibrous tumors (SFTs) are rare mesenchymal pleural neoplasms with an overall good prognosis and low recurrence rate if completely resected and if degree of differentiation is favorable. Within the last decade, advances in research have led to more reliable methods of differentiating SFTs from other soft tissue tumors. Historically, several markers were used to distinguish SFTs from similar tumors, but these markers had poor specificity. Recent evidence showed NAB2-STAT6 fusion gene to be a distinct feature of SFTs with 100% specificity and sensitivity. Surgical resection, with an emphasis on obtaining negative margins, is the mainstay of treatment for SFTs. Preoperative planning with detailed imaging is imperative to delineate the extent of disease and vascular supply. One important radiologic distinction to aid delineation of a pleural-based tumor compared to a pulmonary parenchymal-based tumor is the angle that the tumor forms with the chest wall, which is obtuse for a pleural-based tumor, and acute for tumors of the lung parenchyma. Often, preoperative tissue diagnosis is not available, and surgery is both diagnostic and curative. Intraoperatively, emphasis should be on complete resection with negative margins. SFTs are resected via several approaches: thoracotomy, sternotomy with the option of hemi-clamshell extension, video-assisted thoracoscopic surgery, and robotic approach, which is increasingly being used and is our preference. We recommend a minimally invasive approach for most lesions, and have resected SFTs of the pleura that are up to 12 cm with the robotic approach. However, the current literature often cites 5 cm as the cut off for an open thoracotomy. Nevertheless, even with larger tumors, a minimally invasive robotic approach is our preference and practice. For giant SFTs (> 20 cm), an open approach may be preferable. Multiple thoracotomies and rib resection may be required to gain adequate exposure and ensure complete resection in these tumors. However, it is noteworthy that most of these tumors have a soft consistency and thus, once bagged, can easily be removed minimally invasively, and thus minimally invasive approach should not be completely ruled out. Recurrence in SFTs usually results from incomplete resection and redo surgery may portend a favorable prognosis.

Gastric bypass has grown in popularity in recent years due to its high efficacy in achieving long-term weight loss in patients with morbid obesity. Gastric bypass has been described to further exacerbate baseline nutritional deficiencies due to reduced gastric capacity and malabsorption. In rare cases, when protein deficiency is severe, Kwashiorkor disease may arise. The incidence of Kwashiorkor specifically following gastric bypass is rare, with an incidence of 4.7%. We report a case of a female patient who underwent a gastric bypass and subsequently developed Kwashiorkor. Physicians' suspicion of index for Kwashiorkor should be high for patients presenting with signs or symptoms of severe malnutrition following weight-loss procedures.
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