About

Dr. Micaela Esquivel is a board-certified, fellowship-trained surgeon specializing in bariatric and minimally invasive surgery at Stanford Health Care. She serves as a clinical associate professor in the Department of Surgery, Division of General Surgery at Stanford University School of Medicine. Her clinical expertise includes foregut surgery and bariatric procedures utilizing robotic and therapeutic endoscopic approaches. She developed the Bariatric Endoscopy Program at Stanford and treats patients with hiatal hernias, reflux, and motility disorders of the esophagus and stomach. Her work in endobariatric procedures includes endoscopic sleeve gastroplasty and intragastric balloon, as well as revisions and reductions for patients who have regained weight after bariatric surgery. Dr. Esquivel has a strong focus on health equity and disparities in surgical care, having studied access to surgical services in California and internationally in Zambia and Guatemala. Her research interests include disparities in bariatric surgery, outcomes, and global access to surgical care. She has presented her research at major conferences and authored numerous articles in prominent journals. She is a fellow of the American College of Surgeons and actively participates in professional societies such as ASMBS, the American Foregut Society, and the Society of American Gastrointestinal and Endoscopic Surgeons.

Research topics

• Medicine
• General surgery
• Machine Learning
• Internal medicine
• Computer Science
• Artificial Intelligence
• Surgery
• Computer vision
• Medical physics

Selected publications

• Pyloric Dysfunction: A Review of the Mechanisms, Diagnosis, and Treatment

  Gut and Liver · 2025-03-10 · 5 citations

  reviewOpen access

  Pyloric dysfunction is defined as hypertonia or spasm of the pyloric sphincter. The pylorus plays a key role in gastric emptying, but its function remains incompletely understood. Most studies have focused on gastroparesis regardless of the underlying pathophysiology. Few studies have reported pyloric dysfunction in patients with gastroparesis, and the diagnostic and treatment modalities for pyloric dysfunction are not well established. Recently developed diagnostic modalities assessing pyloric function, such as high-resolution antroduodenal manometry and endoluminal functional lumen imaging, are currently being evaluated. A variety of therapeutic interventions targeting the pylorus, including pharmacologic agents, intrapyloric botulinum injection, endoscopic balloon dilation, stent insertion, surgical pyloroplasty, and gastric peroral endoscopic pyloromyotomy, have been proposed. Among these, gastric peroral endoscopic pyloromyotomy has emerged as a novel, minimally invasive therapy with demonstrated efficacy and safety for refractory gastroparesis. This article reviews the pathophysiology of pyloric dysfunction and the potential diagnostic and therapeutic modalities based on the latest literature.

  PublisherOA PDFDOI

• OR09-05 Perioperative Weight Loss With GLP-1 Receptor Agonists in Patients Receiving Bariatric Surgery

  Journal of the Endocrine Society · 2025-10-01

  articleOpen access

  Abstract Disclosure: A. Rao: None. B. Ruhle: None. M. Ono: None. J.O. Chinn: None. P. Ruhi-Williams: None. L. Kennedy: None. M.M. Esquivel: None. M.E. Hauser: None. D.E. Azagury: Consultant: Form Health, GI Windows, Endolumik. D. Desai: None. Introduction: While bariatric surgery is the most effective tool for weight loss, the role of glucagon-like peptide 1 receptor agonists (GLP-1) in addition to bariatric surgery is underexplored. This study investigates weight loss outcomes in patients on GLP-1 who receive bariatric surgery, with a focus on the perioperative period. Methods: We conducted a retrospective analysis of all metabolic/bariatric surgical procedures performed at Stanford Health Care between January 1, 2019, and December 31, 2023. Adults with obesity who underwent sleeve gastrectomy or gastric bypass were identified and stratified into treatment groups based on the GLP-1 or GLP-1/glucose-dependent insulinotropic polypeptide (GIP) RA prescribed (semaglutide, liraglutide, dulaglutide, and tirzepatide) and the timing of prescription in relation to their operation. Patients who were on GLP-1 prior to the study period, were prescribed but who did not receive the medication, or were on GLP-1 for <4 months all were excluded. Patients were grouped as follows: Group 1) patients prescribed GLP-1 within 2 years before surgery, but not after; Group 2) patients prescribed GLP-1 within 2 years after surgery, but not before; Group 3) patients prescribed GLP-1 both within 2 years before surgery and 2 years after surgery. Patients not prescribed GLP-1 were included as the control group. The primary outcome was percent total body weight loss. Results: There were 846 patients who received bariatric surgery during the study interval, and 568 met inclusion criteria. There were 424 patients in the control group, 32 patients in Group 1, 66 patients in Group 2, and 46 patients in Group 3. Patients in Group 3 had a significantly higher starting BMI compared to other groups. Patients in Group 2 and Group 3 achieved significantly more total body weight loss than Group 1 and control (30.7% and 32.7%, respectively, vs 28.8% in Group 1, and 27% in the control group, p-value = 0.0002). Discussion: The results underscore the synergistic potential of combining GLP-1 RA with bariatric surgery in achieving greater weight loss in the perioperative period. GLP-1 usage in the perioperative period may prime patients for more effective weight loss, potentially by inducing behavior/physiologic changes that complement the metabolic effect of surgery. Patients with very severe obesity likely benefit the most from starting GLP-1 in the preoperative setting and continuing postoperatively. However, if starting BMI is relatively lower, post-operative GLP-1 alone is effective in augmenting weight loss. Conclusion: Patients on GLP-1 receptor agonists both preoperatively and postoperatively relative to bariatric surgery experienced the greatest weight loss. While existing studies have focused on the use of GLP-1 primarily for weight regain, our findings highlight their potential as adjunctive therapy for weight loss during the critical perioperative period. Presentation: Saturday, July 12, 2025

  PublisherOA PDFDOI

• Use of Lower Staple Heights in Robotic Sleeve Gastrectomy: National Trends and Impact on Outcomes

  Annals of Surgery Open · 2025-04-24 · 1 citations

  articleOpen accessSenior authorCorresponding

  Objective: This study aimed to characterize SureForm stapler usage trends in robotic sleeve gastrectomy (RSG) and compare associated outcomes, accounting for staple height used. Background: The proportion of sleeve gastrectomy cases done robotically is increasing, but uncertainty remains about optimal stapler choice, reload height and reinforcement, and the impact of these choices on perioperative outcomes. Methods: Elective laparoscopic and robotic SG performed from January 1, 2019, to February 28, 2023, were identified in the PINC AI Healthcare Database. Patients who underwent RSG were included. RSG with no stapler type/height information was excluded. The incidences of complications such as bleeding, leak, and sepsis in the perioperative period were evaluated using International Classification of Diseases/Current Procedure Terminology codes. Hospital resource utilization data such as length of stay, operative time, intensive care unit utilization, and readmission were also analyzed. Propensity score matching (PSM) analysis was used to compare outcomes. Results: A total of 35,795 RSG were analyzed with 23,904 documenting use of SureForm stapler. Use of at least one SureForm white reload increased from 19.2% to 52.7% in the study period; use of 3 or more white reloads per case increased from 6% to 71%. PSM analysis compared 5795 RSG with any white reload versus 5795 RSG with non-white reloads, showing equivalent complication rates, marginally shorter length of stay, and longer operative time with white reloads. Conclusions: There is a trend toward downsizing to white stapler reloads in RSG without significant changes in perioperative outcomes and minor differences in hospital resource utilization. These findings suggest that white stapler reload use is safe in RSG.

  PublisherDOI

• Timing of Antiobesity Medications and Adolescent Metabolic and Bariatric Surgery

  JAMA Surgery · 2025-10-22

  articleOpen access

  This cohort study investigates the association between preoperative antiobesity medications and weight loss outcomes of adolescent patients undergoing metabolic and bariatric surgery.

  PublisherOA PDFDOI

• Bariatric Surgery: Improving Access without Compromising Outcomes

  Obesity Surgery · 2025-09-08

  articleSenior author
  PublisherDOI

• Mild to moderate GERD before sleeve: Can we better predict post-operative GERD?

  Surgical Endoscopy · 2025-08-28 · 1 citations

  article
  PublisherDOI

• The impact of socioeconomic disadvantage on metabolic and bariatric surgical outcomes using Area Deprivation Index

  Journal of Gastrointestinal Surgery · 2025-06-27

  articleSenior author
  PublisherDOI

• Magnesium and Esophageal Pain After Peroral Endoscopic Myotomy of the Esophagus: A Randomized, Double-Blind, Placebo-Controlled Trial

  Anesthesia & Analgesia · 2024-06-07 · 5 citations

  article

  BACKGROUND: Postoperative esophageal pain occurs in 67% of patients after peroral endoscopic esophageal myotomy (POEM). Magnesium can act as a smooth muscle relaxant. This study investigated whether intraoperative magnesium can reduce postoperative esophageal pain in patients undergoing POEM. METHODS: In this double-blind, placebo-controlled trial, 92 patients were randomized to receive either magnesium sulfate as a 50 mg.kg -1 (total body weight) bolus followed by an infusion at 25 mg.kg -1 .hr -1 , or 0.9% saline. Intraoperative analgesia was standardized in all patients. The primary outcome was the score from a validated, modified Esophageal Symptoms Questionnaire (ESQ) in the postanesthesia care unit (PACU). Pain scores, opioid requirements, and questionnaire scores were collected through postoperative day 1. RESULTS: ESQ scores were significantly lower in the magnesium group in the PACU (median [25th-75th], 24 [18-31] vs 35 [28-42]; median difference [95% confidence interval, CI], 10 [6-13]; P < .0001) and on postoperative day 1 (16 [14-23] vs 30 [24-35]; P < .0001). Less opioids were needed in the magnesium group in the PACU (mean ± standard deviation [SD] [99% CI], 4.7 ± 10 [1-9] mg vs 29 ± 21 [21-37] mg; P < .0001) and on postoperative day 1 (1 ± 3.7 [0-2.5] mg vs 13 ± 23 [4-23] mg; P = .0009). Pain scores were lower in the magnesium group in the PACU (0 [0-3] vs 5 [5-7]; P < .0001) and on postoperative day 1 (0 [0-2] vs 4 [3-5]; P < .0001). CONCLUSIONS: Patients undergoing POEM randomized to receive intraoperative magnesium had sustained reductions in esophageal discomfort severity and opioid requirements 24 hours after surgery.

  PublisherDOI

• Laparoscopic Heller Myotomy and Toupet Fundoplication

  World Journal of Surgery · 2022 · 4 citations

  • Medicine
  • Surgery
  • General surgery

  Esophageal achalasia is a primary motility disorder of unknown origin. The goal of treatment is to eliminate the resistance caused by a non-relaxing lower esophageal sphincter, therefore allowing passage of food and liquid from the esophagus into the stomach. A myotomy with a partial fundoplication (anterior Dor or posterior Toupet) is considered the standard of care for patients with achalasia. In the following review, we describe the indications and technique for a posterior partial fundoplication (Toupet).

  PublisherDOI

• Mo1177: VALUE OF 96-HR AMBULATORY ESOPHAGEAL PH MONITORING IN THE ASSESSMENT OF PATIENTS WITH REFRACTORY ACID REFLUX SYMPTOMS AND THEIR RESPONSE TO ANTI-REFLUX DIET

  Gastroenterology · 2022-05-01

  article
  PublisherDOI

Frequent coauthors

• Tarsicio Uribe‐Leitz

  Harvard University

  96 shared

• Thomas G. Weiser

  61 shared

• David A. Spain

  Stanford University

  51 shared

• Alex B. Haynes

  49 shared

• Lisa M. Knowlton

  Stanford University

  48 shared

• George Molina

  Dana-Farber Brigham Cancer Center

  44 shared

• Kristan Staudenmayer

  Kuwait Petroleum Corporation (Kuwait)

  40 shared

• Atul A. Gawande

  40 shared

Awards & honors

• Fellow of the American College of Surgeons