Prognostic and predictive value of interstitial cells of Cajal populations following stapled transanal rectal resection (STARR) in patients with obstructed defecation syndrome.

Objective: The present study was designed to evaluate the functional outcome of stapled transanal rectal resection (STARR) and to examine the relationship between the population density of the interstitial cells of Cajal (ICC) and the efficacy of the STARR operation in the management of obstructed defecation syndrome (ODS) patients.

Methods: Full-thickness rectal samples were obtained from 50 ODS patients who underwent STARR. Samples were analysed using ICC immunohistochemistry. Clinical and functional parameters obtained with defecography and anorectal manometry were compared with 20 controls.

Results: ICCs were significantly decreased in patients in the submucosal (SM), intramuscular (IM) and myenteric (MY) regions when compared with the control group (<0.05). The mean pre-operative Cleveland Constipation Score (CCS) was 24.2 ± 4.1, whilst the CCS at 1, 2, 3, 4 and 5 years post-operatively decreased significantly (<0.05). At 3 post-operative years, 58.3% (28/48) of the patients reported a favorable outcome (CCS≤10). On univariate analysis, the functional results were worse in those with pre-operative digitation (=0.017), a decreased ICC-MY cell population (=0.067), a higher resting anal canal pressure (=0.039) and a higher rectal sensory threshold (=0.073). Multivariate analysis showed the decreased ICC-MY cell population was an independent predictor for low unfavorable functional outcome (odds ratio=0.097, 95% confidence interval: 0.012-0.766).

Conclusions: STARR achieved acceptable results at the cost of a slight deterioration over a more prolonged follow-up. Patients with a decreased ICC number in the rectal specimen showed an unfavorable functional outcome where pre-operative histological assessment of a full-thickness rectal sample might predict for the functional outcome following STARR.