Dr. Villarreal is a current clinical informatics fellow at Stanford Medicine and first surgical resident to enter the program. He began general surgery training at Stanford in 2020. Dr. Villarreal is a Texas native and hometown is in McAllen TX. He completed medical school at Baylor College of Medicine in 2020 and undergraduate studies in Human Biology at the University of Texas.

During residency, Dr. Villarreal has published numerous articles in a wide range of surgical fields including: pediatric surgery, liver transplantation, trauma critical care and surgical data science. He currently holds the role as president of the resident led surgical research group Surgeon’s Writing About Trauma (SWAT) and mentors medical students and undergrads in conducting surgical related clinical research. He is a member of the Artificial Intelligence in Surgery research group at Stanford focused on leveraging methods in machine learning in the care of transplant patients.

His long-term goals are to apply clinical informatics frameworks to optimize surgical care workflows, enhance intraoperative decision making, and increase accessibility of outpatient surgical services to lower income patients.

Clinical Focus

  • Fellow
  • Clinical Informatics
  • General Surgery
  • Critical Care

All Publications

  • Scoping review of traumatic hemothorax: Evidence and knowledge gaps, from diagnosis to chest tube removal. Surgery Choi, J., Villarreal, J., Andersen, W., Min, J. G., Touponse, G., Wong, C., Spain, D. A., Forrester, J. D. 2021


    BACKGROUND: Traumatic hemothorax is a common injury that invites diagnostic and management strategy debates. Evidence-based management has been associated with improved care efficiency. However, the literature abounds with long-debated, re-emerging, and new questions. We aimed to consolidate up-to-date evidence on traumatic hemothoraces, focusing on clinical conundra debated in literature.METHODS: We conducted a scoping review of 21 clinical conundra in traumatic hemothorax diagnosis and management according to PRISMA-ScR guidelines. Experimental and observational studies evaluating patients (aged ≥18 years) with traumatic hemothoraces were identified through database searches (PubMed, EMBASE, Web of Science, Cochrane Library; database inception to Sep, 26 2020) and bibliography reviews of selected articles. Three reviewers screened and selected articles using standardized forms.RESULTS: We screened 1,440 articles for eligibility, of which 71 met criteria for synthesis. The review comprises 6 sections: (1) Presumptive antibiotics before tube thoracostomy; (2) Initial diagnostic and intervention decisions; (3) Chest tubes; (4) Retained hemothoraces; (5) Delayed hemothoraces; and (6) Chest tube removal). The 21 conundra across these sections follow the format of a question, our recommendation based on interpretation of available evidence, and succinct rationale. Rationale sections detail knowledge gaps and opportunities for future research.CONCLUSION: Even practices engrained into surgical dogma, such as obtaining chest x-rays after inserting or removing chest tubes and mandating operation for patients who develop chest tube output above a certain threshold, deserve re-evaluation. Some knowledge gaps require rigorous future investigation; sound clinical judgment can likely supplement others.

    View details for DOI 10.1016/j.surg.2021.03.030

    View details for PubMedID 33888318

  • Hepatic separation of conjoined twins: Operative technique and review of three-dimensional model utilization. Journal of pediatric surgery Villarreal, J. A., Yoeli, D., Masand, P. M., Galvan, N. T., Olutoye, O. O., Goss, J. A. 2020; 55 (12): 2828-2835


    The separation of conjoined twins is a challenging and rare operation. Recent technological advances in imaging and three-dimensional printing (3DP) have allowed for enhancements in preoperative surgical planning and intraoperative anatomical orientation for complex operations. This report aims to consolidate the current clinical evidence utilizing 3DP models as an effective tool for surgical planning of conjoined twin separation and to detail our surgical approach for complex hepatic separation and management.A literature review was conducted for conjoined twin separations with preoperative use of 3D models including age at attempted separation, operative outcome, 3D modality, and postoperative course between 1998 and 2020. We also conducted a chart review of our electronic medical record for conjoined twin separations between January 2015 and December 2019.We report two cases of conjoined twin separation with preoperative use of 3DP models from our institution: one set in the thoracoomphaloischiopagus orientation and the other set in the thoracoomphalopagus orientation with the presence of intrahepatic vascular anomalies. The literature review produced 10 case reports of conjoined twin separation with use preoperative 3D models accounting for 17 individual separation procedures. We summarize our preoperative radiological planning, the evidence of 3DP models as an educational and preoperative tool, ideal timing for separation, and our surgical approach for complex hepatic separation.Conjoined twin separation requires a multidisciplinary effort to address the multisystem surgical and medical needs of these patients. These complex patients require extensive preoperative imaging for planning separation, and we strongly recommend utilizing 3D printed models when possible for better surgeon understanding of complex variable anatomy. We have found numerous reports of successful conjoined twin separation using 3DP technology in preoperative planning. The use of three-dimensional printed models for preoperative assessments is an invaluable tool and is rapidly improving in fidelity.Operative technique and case series.Level IV.

    View details for DOI 10.1016/j.jpedsurg.2020.06.047

    View details for PubMedID 32792165

  • Combined Lung-Liver and Delayed Kidney Transplantation for Cystic Fibrosis Clinical Approach and Outcome: A Case Report. Transplantation proceedings Zhang, T., Price, M. B., Bravo, N., Villarreal, J. A., Kueht, M. L., Vierling, J. M., Cotton, R., Galvan, T., O'Mahony, C. A., Goss, J. A., Rana, A. 2020; 52 (9): 2824-2826


    Reports on the long-term outcomes and immunosuppressive regimens of multiorgan transplant patients are limited. Here, we describe a patient with cystic fibrosis complicated by multiorgan failure who was successfully treated with combined liver lung transplant and delayed kidney transplant, resulting in excellent outcomes. Delayed kidney transplant was done to reduce the operative stress of a single procedure, giving time for adequate resuscitation and weaning from vasopressors. Our patient's postoperative course was complicated by post-transplant lymphoproliferative disease, which was successfully treated with rituximab and reduced dosages of immunosuppression.

    View details for DOI 10.1016/j.transproceed.2020.02.154

    View details for PubMedID 32389488

  • Are We Out of the Woods Yet? The Aftermath of Resuscitative Thoracotomy. The Journal of surgical research Fitch, J. L., Dieffenbaugher, S., McNutt, M., Miller, C. C., Wainwright, D. J., Villarreal, J. A., Wilson, C. T., Todd, S. R. 2020; 245: 593-599


    After traumatic arrest, resuscitative thoracotomy is lifesaving in appropriately selected patients, yet data are limited regarding hospital course after intensive care unit (ICU) admission. The objective of this study was to describe the natural history of resuscitative thoracotomy survivors admitted to the ICU.We conducted a retrospective review (January 1, 2012-June 30, 2017) of all adult trauma patients who underwent resuscitative thoracotomy after traumatic arrest at two adult level 1 trauma centers. Data evaluated include demographics, injury characteristics, hospital course, and outcome.Over 66 mo, there were 52,624 trauma activations. Two hundred ninety-eight patients underwent resuscitative thoracotomy and 96 (32%) survived to ICU admission. At ICU admission, mean age was 35.8 ± 14.5 y, 79 (82%) were male, 36 (38%) sustained blunt trauma, and the mean injury severity score was 32.3 ± 13.7. Eight blunt and 20 penetrating patients (22% and 34% of ICU admissions, respectively) survived to discharge. 67% of deaths in the ICU occurred within the first 24 h, whereas 90% of those alive at day 21 survived to discharge. For the 28 survivors, mean ICU length of stay was 24.1 ± 17.9 d and mean hospital length of stay was 43.9 ± 32.1 d. Survivors averaged 1.9 ± 1.5 complications. Twenty-four patients (86% of hospital survivors) went home or to a rehabilitation center.After resuscitative thoracotomy and subsequent ICU admission, 29% of patients survived to hospital discharge. Complications and a long hospital stay should be expected, but the functional outcome for survivors is not as bleak as previously reported.

    View details for DOI 10.1016/j.jss.2019.07.014

    View details for PubMedID 31499365

  • Intraoperative blood loss and transfusion during primary pediatric liver transplantation: A single-center experience. Pediatric transplantation Villarreal, J. A., Yoeli, D., Ackah, R. L., Sigireddi, R. R., Yoeli, J. K., Kueht, M. L., Galvan, N. T., Cotton, R. T., Rana, A., O'Mahony, C. A., Goss, J. A. 2019: e13449


    Children undergoing liver transplantation are at a significant risk for intraoperative hemorrhage and thrombotic complications, we aim to identify novel risk factors for massive intraoperative blood loss and transfusion in PLT recipients and describe its impact on graft survival and hospital LOS. We reviewed all primary PLTs performed at our institution between September 2007 and September 2016. Data are presented as n (%) or median (interquartile range). EBL was standardized by weight. Massive EBL and MT were defined as greater than the 85th percentile of the cohort. 250 transplantations were performed during the study period. 38 (15%) recipients had massive EBL, and LOS was 31.5 (15-58) days compared to 11 (7-21) days among those without massive EBL (P < 0.001). MT median LOS was 34 (14-59) days compared to 11 (7-21) days among those without MT (P = 0.001). Upon backward stepwise regression, technical variant graft, operative time, and transfusion of FFP, platelet, and/or cryoprecipitate were significant independent risk factors for massive EBL and MT, while admission from home was a protective factor. Recipient weight was a significant independent risk factor for MT alone. Massive EBL and MT were not statistically significant for overall graft survival. MT was, however, a significant risk factor for 30-day graft loss. PLT recipients with massive EBL or MT had significantly longer LOS and increased 30-day graft loss in patients who required MT. We identified longer operative time and technical variant graft were significant independent risk factors for massive EBL and MT, while being admitted from home was a protective factor.

    View details for DOI 10.1111/petr.13449

    View details for PubMedID 31066990

  • Evidence Versus Practice in Early Drain Removal After Pancreatectomy. The Journal of surgical research Villafane-Ferriol, N., Baugh, K. A., McElhany, A. L., Van Buren, G., Fang, A., Tashakori, E. K., Reyes, J. E., Cao, H. S., Silberfein, E. J., Massarweh, N., Hsu, C., Barakat, O., Schmidt, C., Zyromski, N. J., Dillhoff, M., Villarreal, J. A., Fisher, W. E. 2019; 236: 332-339


    Early drain removal when postoperative day (POD) one drain fluid amylase (DFA) was ≤5000 U/L reduced complications in a previous randomized controlled trial. We hypothesized that most surgeons continue to remove drains late and this is associated with inferior outcomes.We assessed the practice of surgeons in a prospectively maintained pancreas surgery registry to determine the association between timing of drain removal with demographics, comorbidities, and complications. We selected patients with POD1 DFA ≤5000 U/L and excluded those without drains, and subjects without data on POD1 DFA or timing of drain removal. Early drain removal was defined as ≤ POD5.Two hundred and forty four patients met inclusion criteria. Only 90 (37%) had drains removed early. Estimated blood loss was greater in the late removal group (190 mL versus 100 mL, P = 0.005) and pathological findings associated with soft gland texture were more frequent (97 [63%] versus 35 [39%], P < 0.0001). Patients in the late drain removal group had more complications (84 [55%] versus 30 [33%], P = 0.001) including pancreatic fistula (55 [36%] versus 4 [4%], P < 0.0001), delayed gastric emptying (27 [18%] versus 3 [3%], P = 0.002), and longer length of stay (7 d versus 5 d, P < 0.0001). In subset analysis for procedure type, complications and pancreatic fistula remained significant for both pancreatoduodenectomy and distal pancreatectomy.Despite level one data suggesting improved outcomes with early removal when POD1 DFA is ≤ 5000 U/L, experienced pancreas surgeons more frequently removed drains late. This practice was associated with known risk factors (estimated blood loss, soft pancreas) and may be associated with inferior outcomes suggesting potential for improvement.

    View details for DOI 10.1016/j.jss.2018.11.048

    View details for PubMedID 30694774

    View details for PubMedCentralID PMC6377814

  • Extracorporeal Liver Support in Patients with Acute Liver Failure. Texas Heart Institute journal Villarreal, J. A., Sussman, N. L. 2019; 46 (1): 67-68

    View details for DOI 10.14503/THIJ-18-6744

    View details for PubMedID 30833847

    View details for PubMedCentralID PMC6379009

  • Cutaneous Mucormycosis in Solid Organ Transplant Recipients after Hurricane Harvey: Short- and Long-term Management. Plastic and reconstructive surgery. Global open Kueht, M., Villarreal, J. A., Reece, E., Galvan, N. T., Mysore, K., Restrepo, A., Quintanilla, N., Rana, A., Goss, J. 2019; 7 (1): e2041


    In the fall of 2017, Hurricane Harvey, one of the most costly hurricanes in American history, ravaged the Texas Gulf Coast, interrupting basic sanitation systems to hundreds of thousands of Texas residents. In the aftermath of Hurricane Harvey, our Houston hospitals noted an uptick in the incidence of cases of mucormycosis. Among the most vulnerable and affected have been immunocompromised transplant recipients. Here, we describe the successful management of 2 patients with atypical presentations of mucormycosis, 2 cutaneous infections after liver transplantation. Our comprehensive treatment strategy based upon guidelines and experience included coordinating aggressive surgical and medical therapies. We discuss our approach to surgical management including the extent and frequency of debridement, the methods of assessing disease-free margins, and minimizing the morbidity of radical debridement with temporary coverage and forethought to long-term reconstruction. Additionally, we describe the concurrent medical management, including type, route, and duration of antifungal therapy, minimizing suppression of the innate immune system, and optimizing the wound healing environment through maintaining nutritional status.

    View details for DOI 10.1097/GOX.0000000000002041

    View details for PubMedID 30859029

    View details for PubMedCentralID PMC6382219