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In 2016, Dr. Ian Grimm completed a summer sabbatical in Japan, where he studied endoscopic submucosal dissection (ESD) and peroral endoscopic myotomy (POEM) with master endoscopists at nine major medical centers throughout the country. He has since applied these cutting-edge skills within our growing UNC Advanced and Therapeutic Endoscopy Program.

Dr. Grimm at Peace Park.

Endoscopic Submucosal Dissection

With over 25 years of experience in performing advanced mucosal resections for large gastric, duodenal, and colonic polyps, the addition of ESD has helped Dr. Grimm further expand his referral base well beyond North Carolina, to include the entire southeastern US.

From a large volume of polypectomy referrals, Dr. Grimm can often identify patients who are ideal candidates for ESD, especially individuals with superficial neoplastic lesions who might otherwise require surgery. Advanced rectal polyps account for a sizable proportion of the ESD procedures performed at UNC. This is because these lesions have a disproportionately high risk of containing superficially invasive cancer, as compared to advanced polyps elsewhere in the colon, and because the surgical options for treating these patients are associated with significant costs, risks, and morbidity. Recent advances in technology, such as the ORISE tissue retraction system and the full-thickness resection device (FTRD), can improve the efficiency of rectal ESD and further expand the range of patients that can benefit from endoluminal procedures, and help patients avoid unnecessary surgery.

Grimm - ESD1
85 year old man referred to UNC for rectal mass. Tubulovillous adenoma with intramucosal carcinoma on biopsies. He had earlier been referred to 2 colorectal surgeons who deemed him unfit for surgery.


Upon returning from Japan, Dr. Grimm also added POEM to the menu of treatment options offered to patients with spastic disorders of the esophagus, and over time, the volume of POEM referrals has continued to increase. POEM is proving to be an effective solution for patients with type 3 achalasia, Jackhammer esophagus, and distal esophageal spasm – conditions that lack other good treatment options. And although POEM can be offered to all achalasia patients, it is particularly useful in patients who are suboptimal candidates for a laparoscopic Heller myotomy, or who have relapsed from a prior Heller myotomy.

Grimm - ESD2
Dr. Grimm resected the lesion using ESD.Left: retroflexed view of post-ESD resection site Right: en bloc specimen, 3.5 by 2.4 cm Pathology: Well differentiated, low grade adenocarcinoma; Negative margins; 2mm to deep margin “Favorable histology” by NCCI

Other Complementary Therapies

Dr. Grimm’s advanced skills in ESD and POEM are highly complementary with one another, and readily translate to a wide range of other forms of endoluminal therapy, such as Zenker’s diverticulotomy, submucosal tunneling and endoscopic resection (STER) for resection of submucosal lesions of the esophagus and stomach, and gastric pyloromyotomy or G-POEM, for postoperative gastroparesis.

Delivering of these cutting-edge procedures would not be possible without support from UNC Hospitals and the Division of Gastroenterology and Hepatology at UNC. Patients referred to Dr. Grimm often benefit from comprehensive care courtesy of UNC GI’s other outstanding clinical programs, such as the UNC High Risk Gastrointestinal Cancer Clinic (led by Dr. Robert Sandler), and the UNC Center for Esophageal Diseases and Swallowing (Dr. Nick Shaheen and Shifali Aurora).

Research and Training

Beyond clinical care, Dr. Grimm collaborates with several UNC GI junior faculty members who perform research on colorectal cancer prevention, colonic polyps, and endoscopic polypectomy. A recent highlight is a study published in Gastroenterology that found the incidence of surgery for nonmalignant colorectal polyps to be increasing, in spite of advances in endoscopic resection. Dr. Grimm is also dedicated sharing his experience with UNC GI junior faculty and trainees. Dr. Dan Kroch, who recently joined the faculty, has been studying POEM and ESD under Dr. Grimm’s guidance, and is regularly assisting in these procedures.

Referrals to Dr. Grimm can be made by contacting Heather Solender in the Advanced Endoscopy office at UNC, at 984-974-5058 or .