728 THE PATH TO WHIPPLE RECONSTRUCTION: TRANS-MESOCOLON OR THROUGH LIGAMENT OF TREITZ? Adriana C. Gamboa, Mohammad Y. Zaidi, Rachel M. Lee, Juan M. Sarmiento, David Kooby, Maria C. Russell, Kenneth Cardona, Shishir K. Maithel Background The path of the jejunal limb for reconstruction of the pancreatic anastomosis during pancreaticoduodenectomy (PD) for pancreatic ductal adenocarcinoma (PDAC) can be trans-mesocolon (TM) or through the ligament of Treitz (LOT). Even after curative intent PD, incidence of recurrence in the surgical bed remains high and may lead to obstruction of the afferent limb. However, the association between path of jejunal limb and incidence of afferent limb obstruction (ALO) has not been studied. Primary aim was to determine whether path of reconstruction predisposes to ALO in the setting of local recurrence. Methods Pts who underwent PD for PDAC(2008-18) from a single institution were identified. As disease recurrence is the predominant cause of ALO, analysis was limited to pts with known recurrence at date of last f/u. Given a known median time to recurrence of 8-10mos after resection for PDAC, analysis was further limited to pts with at least 8mos of f/u. Primary outcome was incidence of ALO. Results Of 517pts identified, 179 were included. Median age was 65yrs; 51% were male. Median f/u was 22mos. Path of reconstruction was TM in 36%(n=64) and through LOT in 64%(n=115). There was no difference between the two groups in clinicopathologic factors including age, tumor differentiation, grade, T-stage, N- stage, LVI or PNI (all p>0.05). Importantly, there was no difference in retroperitoneal margin positivity between groups (TM:8% vs LOT:10%, p=0.79). Both groups had similar post- operative outcomes including incidence of pancreatic fistula (TM:5% vs LOT:6%, p=0.74), median LOS (TM:6d vs LOT:6d, p=0.89) and median f/u (TM:21mos vs LOT:23mos, p= 0.68). ALO was detected in 8%(n=14) of which 14%(n=2) were in the TM group and 86%(n=12) were in the LOT group. Therefore, incidence of ALO was 3.1% in the TM group and 10.4% in the LOT group resulting in an absolute risk increase of 7.3%, risk ratio of 3.4 and relative risk increase of 2.3. There was no difference in median time to ALO between the groups (17.6mos vs 18.5mos, p=1.0). ALO was caused by locally recurrent PDAC in 93%(n=13) and kinking of the duodenojejunal anastomosis in 7%(n=1). Intervention was performed in 71%(n=10) and included surgical bypass in 29%(n=4), percutaneous drain in 21%(n=3) and endoscopic/surgical decompression in 21%(n=3). Conclusion Afferent limb obstruction is a known complication after PD for PDAC due to local recurrence in the surgical bed. This study shows that path of jejunal limb through the LOT may be associated with a higher incidence of afferent limb obstruction compared to TM as the position of the afferent limb in the surgical bed may be more predisposed to obstruction after local recur- rence. Larger studies are needed; however, given this potential risk of subsequent obstruction, these data suggest that the reconstruction paths may not be equivalent when performing PD for PDAC. 729 STERILITY CULTURES FOLLOWING PANCREATECTOMY WITH ISLET AUTOTRANSPLANTATION IN THE PEDIATRIC POPULATION: DO THEY MATTER? Alexander R. Cortez, Al-Faraaz Kassam, Tom K. Lin, Grant C. Paulsen, Todd M. Jenkins, Lara A. Danziger-Isakov, Maisam Abu-El-Haija, Jaimie D. Nathan Purpose Pancreatectomy with islet autotransplantation (IAT) is a treatment for children with chronic pancreatitis refractory to medical and endoscopic management. Sterility cultures from the pancreas and islet cell solutions are often positive, yet the implications of transplant- ing these contaminated media have not been studied in the pediatric population. Methods A retrospective review of all patients who underwent IAT from 2015-2018 at a single institution was performed. Sterility culture data for each patient were obtained and included results from the transport media (pancreas preservation solution) and transplant media (fluid containing the final islets for transplantation). All patients received prophylactic perioperative meropenem and vancomycin for 72 hours per our protocol. If cultures resulted positive, antibiotics were extended for a total of seven days. Primary outcomes were postoperative fever and 30-day infectious complications. Results 41 patients underwent IAT during the study period, of whom 39 had total pancreatectomy and 2 had subtotal pancreatectomy. Seventeen (41.5%) patients had negative cultures of both the transport and transplant media, while 24 (58.5%) patients had a positive culture from either sample. Of these patients, 13 (31.7%) were positive in both, 10 (24.4%) had positive transport media only, and 1 (2.4%) had positive transplant media only (FIGURE A). Among these positive cultures, a variety of gram-positive, gram-negative, and fungal organisms were isolated (FIGURE B). Patients with a positive culture were similar with regard to age, gender, etiology, and disease duration (all p > 0.05) compared to patients with negative cultures. A similar number of patients in each cohort underwent ERCP prior to IAT (95.8% vs 82.4%, p=0.29), but the positive group was more likely to have had a sphincterotomy (100.0% vs 78.6%, p=0.04) and trended toward a higher likelihood of having an existing pancreatic stent at the time of surgery (26.1% vs 0%, p=0.07). There were no differences in postoperative fever or 30-day infectious complications (p > 0.05 for each) (TABLE). Conclusion This is the first study to explore the impact of positive sterility cultures following pancreatectomy with IAT on postoperative infectious outcomes in the pediatric population. Preoperative instrumentation of the pan- creatic duct is a risk factor for positive cultures, and while the majority of patients had a positive culture, a positive culture was not associated with post-IAT infection or morbidity. Future work is necessary to study the optimal perioperative antibiotic regimen in these patients. S-1405 SSAT Abstracts The majority of patients have a positive sterility culture during IAT. (A) Distribution of sterility culture results for transport and transplant media. (B) Microorganisms isolated from IAT sterility cultures. Demographics and outcomes for patients with positive versus negative sterility cultures following IAT 730 THROMBOEMBOLIC RISK IN PATIENTS UNDERGOING ABDOMINO/ PELVIC SURGERY FOR VARIOUS MALIGNANCIES Jessica Crystal, Nicholas Manguso, James M. Mirocha, Allan W. Silberman Introduction: Malignancy is a known risk factor for venous thromboembolism (VTE). The risk may vary with the type of malignancy. Methods: We retrospectively reviewed 464 patients who were operated on by a surgical oncologist for either a history of prior, current, or presumed diagnosis of malignancy from January 2009 through September 2018. Patients with diagnoses of hepatopancreaticobiliary (HPB), sarcoma, colorectal/anal, gastric, GIST, esophageal, and benign tumors were included. These patients received preoperative epidural analgesia without postoperative chemical VTE prophylaxis. Lower extremity venous duplex scans (VDS) were performed pre- and postoperatively. Demographics, procedures, and above the knee VTE outcomes were reviewed. Results: The incidence of a history of prior VTE was 4.7% (22/464) in all patients, 5.2% (22/423) in the patients with malignancy, and 0% (0/41) in the benign cohort. Preoperative duplex was positive for VTE in 3.4% (16/464) of the patients, 3.5% (15/423) of the malignant cohort, and 2.4% (1/41) in the benign cohort. Postoperative duplex was positive for VTE in 5.0% (23/464) of the patients, 5.4% (22/423) of the patients with malignancy, and 2.4% (1/41) in the benign cohort. New post-op VTE (defined as VTE in patients without any prior history or preoperative VTE) occurred in 1.1% (5/464) of the total patients, 0.9% (4/423) in the malignant cohort, and 2.4% (1/41) in the benign cohort. No patients developed postoperative pulmonary embolism. The rates of prior VTE varied among histology type, p=0.009. Patients with HPB tumors had the highest prior VTE rate, with a frequency of 19.4% (7/36), while patients with sarcoma had a rate of 5.7% (9/158). Patients with the other malignancies had rates less than 5%. There was a similar pattern for patients who developed preoperative VTE, with HPB having the highest frequency at 13.9% (5/36), but none of the aforementioned malignancies had rates greater than 4%. The varying rates of VTE among these cancer types was not statistically significant, p =0.073. The postoperative VTE rates varied among histology type, p=0.024. Postoperative VTE was highest in HPB tumors with a frequency of 19.4% (7/36), 4.8% (3/ 63) in patients with gastric cancer, 4.6% (5/108) in patients with colorectal/anal cancer, and less than 4% in the other malignancies. Only 5 patients had new postoperative DVTs. One of these patients had a benign tumor. Conclusions: Our data suggests that not all patients with malignancies undergoing major oncologic surgery are at the same risk of prior, pre-, and postoperative VTE. However, regardless of histology, they are at increased risk of VTE compared to the benign cohort. Preoperative duplex screening should be considered for these high risk patients. SSAT Abstracts