Surgical management of Crohn's disease is one of the most challenging and complex tasks faced by colorectal surgeons today. Data that can help guide its management are sorely needed.
In this setting, surgeons must adhere to 3 goals: (1) alleviate the immediate Crohn's complication, whether it is obstruction, fistula/abscess, or bleeding; (2) preserve as much bowel length as possible; and (3) reduce the rate of future recurrence. It is this third goal that has been marred by a lack of consistent data, for which Zhu et al. (1) aim to provide additional evidence.
We applaud the study by Zhu et al., (1) published in this issue of Clinical and Translational Gastroenterology, addressing the question of whether a more extended mesenteric resection can decrease surgical recurrence in Crohn's colitis. The authors followed up 126 patients who had their initial operation between 2000 and 2018 at a large inflammatory bowel disease center. Their experience demonstrates that in the 66 patients with extensive mesenteric excision (EME), patients had both a longer surgical recurrence-free interval and a lower rate of subsequent surgeries compared with the 60 patients who had limited mesenteric excision (LME). This association remained statistically significant both in multivariate analysis and in subgroup analysis, looking only at the 101 patients who had an anastomosis. Zhu et al. concluded that EME resulted in improved long-term outcomes and suggested that EME be considered a standard approach for Crohn's colectomies.
Although it is pathophysiologically feasible for the mesentery to be a harbinger of Crohn's recurrence—and the authors have nicely summarized the translational evidence—there are a number of factors whereby the current findings do not sway our clinical practice yet. The main caveat here is that there remains significant bias in determining which patients were sorted to the EME vs LME group. First, it seems that the labeling of patients as either EME or LME was not conducted prescriptively by the operating surgeon but rather established from operative records by the authors. By this method, both the accuracy of the documentation and the specificity of the operative description can introduce bias. Thus, there lacks objectivity regarding just how much mesentery was resected.
Second, the extent of mesenteric resection is truly a spectrum and not a dichotomous choice (unlike, for example, specifying whether the inferior mesenteric artery vs the superior hemorrhoidal artery was ligated). The authors describe an LME as dividing mesentery close to the bowel wall, whereas an EME is similar to an oncologic resection, but at the same time not venturing too close to the root region of the mesentery because it was too dangerous. Depending on the length of the mesentery and other patient-related anatomic factors, how much colon was resected, and surgeon style, the resection line might fall in between true LME and EME. In addition, one portion of the resected colon might have an LME and another portion an EME.
Third, and perhaps the most important, are a myriad of confounding factors that can sway how much mesentery is resected by the surgeon. Mesenteric thickness, vascular patterns, the degree of inflammation of the corresponding colon, the length of the resected colon, and patient habitus can all affect the surgeon's in-the-moment decision. These factors may also be associated with different Crohn's disease phenotypes, as opposed to differences in operative techniques, which may be the underlying factor resulting in the observed differences in long-term outcomes. Although we concede that it is difficult to document and adjust for these variables, several of these may affect recurrence rate. Ultimately, the authors say that whether an EME or LME was performed was according to individual surgeon's discretion.
There is another aspect of this study that also warrants discussion: what determines whether a patient has ultimately failed and, therefore, requires a second operation? This is an important question because a second operation is the primary end point of this study but is susceptible to clinical discretion. Further studies exploring this topic would find strength in reporting other objective measures of Crohn's disease recurrence and standardizing indications for a second surgery or possibly other clinically significant recurrence. How the decision was reached in this study is not well reported. It would be insightful if Zhu et al. (1) shared how many patients had clinical recurrence of Crohn's in these 2 cohorts and whether the recurrence involved only the remaining colon, regardless of whether said recurrence needed surgery.
Finally, in the past few years, the medical management of Crohn's disease has evolved faster than surgical management. It is unclear whether the differences in the reoperative rates between the LME and EME groups would persist if patients would have been optimally and aggressively treated postoperatively with the newer biologic agents that were unavailable during the bulk of this study.
Ultimately, thoughtfully designed, prospective studies are needed to confirm the laudable reported retrospective experience by Zhu et al. (1) on outcomes following LME vs EME in Crohn's colitis. In the meantime, surgeons still need to maintain a high level of respect for handling the inflamed mesentery in patients with Crohn's disease. Smoking and medical therapy remain the principle modifiable risk factors for recurrence as we await additional evidence clarifying whether the extent of mesenteric resection is truly a factor influencing Crohn's disease outcomes.
CONFLICTS OF INTEREST
Guarantor of the article: Eugenia Shmidt, MD.
Specific author contributions: A.S.: drafting manuscript for editorial. E.S.: reviewing initial paper and reviewing and drafting current editorial. G.B.M.: reviewing initial paper and reviewing and drafting current editorial.
Financial support: None to report.
Potential competing interests: None to report.
1. Zhu Y, Qian W, Huang L, et al. Role of extended mesenteric excision in postoperative recurrence of Crohn's colitis: A single-center study. Clin Translational Gastroenterol 2021;12:e00407.