Post-transanal endoscopic microsurgery (TEM) syndrome: a constellation of symptoms resulting from localized inflammatory changes after TEM.

Background: Transanal endoscopic microsurgery (TEM) is a safe and effective therapy for local excision of rectal lesions, but early postoperative infectious and inflammatory complications are variably defined in the literature. The aim of this study was to describe post-TEM syndrome, a cluster of postoperative symptoms related to a local inflammatory process seen in a subset of patients after TEM.

Methods: We conducted a retrospective cohort study using prospectively collected observational data of all patients who underwent TEM at St. Paul's Hospital in Vancouver, British Columbia, between 2006 and 2017.

Results: During the study period, 795 patients were treated by TEM at the study institution. Of these, 56 patients had postoperative pain or fever and 26 patients were determined to have post-TEM syndrome based on our definition. Sixteen patients presented within the first 2 postoperative days, with all patients presenting within 1 week. All patients who underwent cross-sectional imaging (n = 11) had a combination of inflammatory changes with stranding and free fluid, or with small bubbles of free intraperitoneal, retroperitoneal, or mesorectal air, or with both; they did not have signs of free perforation or abscess at the surgical site. Nearly all patients with post-TEM syndrome (96%) did not progress to further infectious complications. Most patients' (92%) post-TEM symptoms resolved within 1 week of conservative treatment.

Conclusion: We provided a description of post-TEM syndrome, the constellation of symptoms arising from a localized inflammatory response in a subset of patients after TEM. This syndrome is uncommon, and nearly all patients recovered with conservative management without a need for more invasive intervention.