Rectal hyposensitivity and functional anorectal outlet obstruction are common entities in patients with functional constipation but are not significantly associated

Abstract

Background/AimsThe causes of functional anorectal outlet obstruction (outlet obstruction) include functional defecation disorder (FDD), rectocele, and rectal intussusception (RI). It is unclear whether outlet obstruction is associated with rectal hyposensitivity (RH) in patients with functional constipation (FC). The aim of this study was to determine the association between RH and outlet obstruction in patients with FC.MethodsThis was a retrospective study using a prospectively collected constipation database, and the population comprised 107 patients with FC (100 females; median age, 49 years). We performed anorectal manometry, defecography, rectal barostat, and at least two tests (balloon expulsion test, electromyography, or colon transit time study). RH was defined as one or more sensory threshold pressures raised beyond the normal range on rectal barostat. We investigated the association between the presence of RH and an outlet obstruction such as large rectocele (> 2 cm in size), RI, or FDD.ResultsForty patients (37.4%) had RH. No significant difference was observed in RH between patients with small and large rectoceles (22 [44.9%] vs. 18 [31%], respectively; p = 0.140). No significant difference was observed in RH between the non-RI and RI groups (36 [36.7%] vs. 4 [30.8%], respectively; p = 0.599). Furthermore, no significant difference in RH was observed between the non-FDD and FDD groups (19 [35.8%] vs. 21 [38.9%], respectively; p = 0.745).ConclusionsRH and outlet obstruction are common entities but appear not to be significantly associated.

Rectal Hyposensitivity Is Associated With a Defecatory Disorder But Not Delayed Colon Transit Time in a Functional Constipation Population

“…RH is presented as a diminished perception of rectal distension and defined as elevation of 1 or more of the 3 sensory thresholds (threshold volumes for first sensation, urgency, and maximum discomfort) in most studies. 15 , 16 Our data suggested that all 3 sensory thresholds were significant higher in FC patients compared with healthy volunteers. According to the normative data derived from 60 healthy volunteers, we detected RH in 122/218 (56.0%) of patients with FC.…”

“…Lee's study included 107 FC patients, however, 21% (23 of 107) of all patients had history of spinal surgery, diabetes mellitus, or pelvic surgery (hysterectomy, ovarian surgery, and bladder surgery). 15 Wijffels’ study only included constipated patients with high-grade internal rectal prolapse. 16 We think that these patients do not fulfill the criteria for FC.…”

“… 10 , 12 – 14 However, the results from 2 recent large clinical studies did not support this conclusion. 15 , 16 Lee et al 15 and Wijffels et al 16 reported that RH was not associated with the incidence of obstructed defecation in constipated patients. It is worth noting that a number of patients included in their studies were characterized by internal rectal prolapse, rectal intussusceptions, or rectocele.…”

Physiology of the Rectum and Anus

“…Probably the most important cause of hyposensitivity is constipation and evacuation problems with dyssynergia, thus by stretching the rectum further deteriorating rectal sensitivity (Lee et al 2013;Lam and Felt-Bersma 2013). Other causes of hyposensibility are the same neurological disorders as mentioned previously with internal and external sphincter dysfunction.…”

Psychosocial Factors and Rectal Hyposensitivity

“…However it is noted that the diagnostic method most commonly used in assessment of sensory function is not barostat testing but simple balloon test. Recently, Lee et al4 reported that RH and functional anorectal outlet obstruction are common entities but appear not to be significantly associated. Contrary to previous knowledge, RH was not significantly related to functional factors including dyssynergic defecation, rectocele and rectal intussusception in the study using gold standard method (barostat).…”