Persistent Mesorectal Inflammatory Activity is Associated With Complications After Proctectomy in Crohn's Disease.

Background And Aims: Rectal resection in inflammatory bowel disease [IBD] is frequently complicated by disturbed perineal wound healing. Close rectal dissection, where the mesorectum remains in situ, is hypothesized to reduce complications by minimizing dead space, compared to total mesorectal excision. The aim of this study was to analyse post-operative outcomes of both techniques. In addition, immune activity in mesorectal tissue was assessed.

Methods: Perineal complications and healing were retrospectively assessed in a series of 74 IBD patients undergoing proctectomy using close rectal dissection or total mesorectal excision. The mesorectums of 15 patients were analysed by fluorescence-activated cell sorting, immunofluorescence and in situ hybridization. Based on the clinical and in vitro findings, a novel surgical approach for Crohn's disease patients with disturbed perineal healing after proctectomy was developed.

Results: In Crohn's disease, perineal complications were more frequent after close rectal dissection than after total mesorectal excision [59.5% vs 17.6%; p = 0.007] with lower healing rates [51.4% vs 88.2%; p = 0.014]. No differences were observed in ulcerative colitis. The mesorectal tissue in Crohn's disease contained enhanced numbers of tumour necrosis factor α-producing CD14+ macrophages, with less expression of the wound-healing marker CD206. Based on these findings, mesorectal excision with omentoplasty was performed in eight patients with perineal complications after close rectal dissection, resulting in complete perineal wound closure in six. Pro-inflammatory characteristics remained present in the mesorectum after close rectal dissection in these patients.

Conclusions: In Crohn's disease, close rectal dissection resulted in more perineal complications, associated with a pro-inflammatory immune status of the mesorectal tissue. Excision of this pro-inflammatory mesenteric tissue resulted in improved perineal healing rates.