Colonic transit in patients after anterior resection: prospective, comparative study using single-photon emission CT/CT scintigraphy

Abstract

Background Bowel dysfunction after anterior resection is well documented, but its pathophysiology remains poorly understood. No study has assessed whether postoperative variation in colonic transit contributes to symptoms. This study measured colonic transit using planar scintigraphy and single‐photon emission CT (SPECT)/CT in patients after anterior resection, stratified according to postoperative bowel function. Methods Symptoms were assessed using the low anterior resection syndrome (LARS) score. Following gallium‐67 ingestion, scintigraphy was performed at predefined time points. Nine regions of interest were defined, and geometric centre (GC), percentage isotope retained, GC velocity index and colonic half‐clearance time (T½) determined. Transit parameters were compared between subgroups based on LARS score using receiver operating characteristic (ROC) curve analyses. Results Fifty patients (37 men; median age 72·6 (range 44·4–87·7) years) underwent planar and SPECT scintigraphy. Overall, 17 patients had major and nine had minor LARS; 24 did not have LARS. There were significant differences in transit profiles between patients with major LARs and those without LARS: GCs were greater (median 5·94 (range 2·35–7·72) versus 4·30 (2·12–6·47) at 32 h; P = 0·015); the percentage retained isotope was lower (median 53·8 (range 6·5–100) versus 89·9 (38·4–100) per cent at 32 h; P = 0·002); GC velocity indices were greater (median 1·70 (range 1·18–1·92) versus 1·45 (0·98–1·80); P = 0·013); and T½ was shorter (median 38·3 (17·0–65·0) versus 57·0 (32·1–160·0) h; P = 0·003). Percentage tracer retained at 32 h best discriminated major LARS from no LARS (area under curve (AUC) 0·828). Conclusion Patients with major LARS had accelerated colonic transit compared with those without LARS, which may help explain postoperative bowel dysfunction in this group. The percentage tracer retained at 32 h had the greatest AUC value in discriminating such patients.

Altered colonic motility is associated with low anterior resection syndrome

“…Mochiki et al found that, while a 300‐kcal meal did not induce contractions in healthy controls, patients with increased stool frequency had relative hypermotility proximal to the anastomosis compared to those with normal stool frequency, suggesting an increased gastrocolic reflex [15]. More recently, patients with major LARS have been shown to have increased colonic transit compared to patients with no‐LARS [16]. Patients with major LARS have also been shown to have a significant increase in post‐prandial neorectal pressure compared to patients without LARS after total mesorectal excision [17].…”

The role of colonic motility in low anterior resection syndrome

“…In an anorectal physiology study, 23 patients with major LARS had a hyperactive postprandial response with a significant increase in postprandial neorectal pressure compared to patients without LARS (n = 9) after total mesorectal excision (85). More recently, colonic transit studies have demonstrated that patients with major LARS have significantly faster transit compared to those with minor or no LARS (26). Increased transit could be a consequence of either hypofunction of the rectosigmoid brake, or overactivity of proximal propulsive activity, further supporting the role of altered colonic motility in LARS.…”

“…While anorectal factors have been extensively researched with regards to their role in LARS (17,(21)(22)(23)(24), less is known about the role of colonic physiology in the aetiology of LARS. Research has continued to emerge that significant alterations in colonic motility are present in LARS, likely demonstrating an underappreciated pathophysiological mechanism (25,26). This review will focus on this important role of colonic motility and its implications in LARS.…”

Altered colonic motility is associated with low anterior resection syndrome, by Keane et al

“…There are increasing data from different modalities on changes seen in patient with major LARS including the use of SPECT, multimodal rectal stimulation, anorectal physiology tests and HRM [4,5].…”

“…There are increasing data from different modalities on changes seen in patient with major LARS including the use of SPECT, multimodal rectal stimulation, anorectal physiology tests and HRM [4,5]. The challenge will be to understand how to combine the data from these approaches to better understand the complex pathophysiology underlying LARS and develop improved therapeutic approaches but also preventative strategies.…”