Absent or impaired rectoanal inhibitory reflex as a diagnostic factor for high-grade (grade III–V) rectal prolapse: a retrospective study

Background Clinically diagnosing high-grade (III–V) rectal prolapse might be difficult, and the prolapse can often be overlooked. Even though defecography is the significant diagnostic tool for rectal prolapse, it is noticed that rectoanal inhibitory reflex (RAIR) can be associated with rectal prolapse. This study investigated whether RAIR can be used as a diagnostic factor for rectal prolapse. Methods In this retrospective study, we evaluated 107 patients who underwent both anorectal manometry and defecography between July 2012 and December 2019. Rectal prolapse was classified in accordance with the Oxford Rectal Prolapse Grading System. Patients in the high-grade (III–V) rectal prolapse (high-grade group, n = 30), and patients with no rectal prolapse or low-grade (I, II) rectal prolapse (low-grade group, n = 77) were analyzed. Clinical variables, including symptoms such as fecal incontinence, feeling of prolapse, and history were collected. Symptoms were assessed using yes/no surveys answered by the patients. The manometric results were also evaluated. Results Frequencies of fecal incontinence (p = 0.002) and feeling of prolapse (p < 0.001) were significantly higher in the high-grade group. The maximum resting (77.5 vs. 96 mmHg, p = 0.011) and squeezing (128.7 vs. 165 mmHg, p = 0.010) anal pressures were significantly lower in the high-grade group. The frequency of absent or impaired RAIR was significantly higher in the high-grade group (19 cases, 63% vs. 20 cases, 26%, p < 0.001). In a multivariate analysis, the feeling of prolapse (odds ratio [OR], 23.88; 95% confidence interval [CI], 4.43–128.78; p < 0.001) and absent or impaired RAIR (OR, 5.36; 95% CI, 1.91–15.04, p = 0.001) were independent factors of high-grade (III–V) rectal prolapse. In addition, the percentage of the absent or impaired RAIR significantly increased with grading increase of rectal prolapse (p < 0.001). The sensitivity of absent or impaired RAIR as a predictor of high-grade prolapse was 63.3% and specificity 74.0%. Conclusions Absent or impaired RAIR was a meaningful diagnostic factor of high-grade (III–V) rectal prolapse. Furthermore, the absent or impaired reflex had a positive linear trend according to the increase of rectal prolapse grading.

Changes in the parameters of the rectoanal inhibitory reflex in children with functional constipation and large rectum

Background. Abdominal ultrasound and anorectal manometry are part of the investigations used to assess children with functional constipation. This study aimed at assessing the changes in the characteristics of the rectoanal inhibitory reflex (RAIR) in children with functional constipation and correlating them with the dimensions of the rectum, measured by abdominal ultrasound. A secondary objective was to compare the rectum size in children with and without constipation. Method. We retrospectively reviewed the clinical data and investigations results of 51 children (mean age±standard deviation (SD) =5.8±3.5 years) with functional constipation who came to our clinic between January 2013 and February 2020. The assessment of these patients included both the assessment of the transverse diameter of the rectal ampulla by abdominal ultrasound and anorectal manometry. The studied parameters of RAIR were: the minimal volume of air necessary to induce RAIR, in all the patients with functional constipation, and in 20 of them, relaxation time, latency and relaxation percentage. A control group was formed of 27 children (mean age±DS=5.1±4 years) without digestive diseases and with normal intestinal transit, who were assessed by abdominal ultrasound. Results. The mean value ±SD of the volume of air necessary to induce RAIR was 21.9±12.1 cm3 air. There was no correlation between the rectum transverse diameter and the minimal air volume that triggered RAIR (r=-0.01, p=0.94). The mean value ±SD of the transverse diameter of the rectum in patients with functional constipation was 39±14 mm, and in children without constipation 26±6 mm (p<0.05). The mean duration of the symptoms in children with functional constipation was 2.8 years. Conclusions. There were no correlations between the volume of air that induced the RAIR and the transverse diameter of the rectum in children with functional constipation. The transverse diameter of the rectum was increased in children with long-term functional constipation.

Oxycodone and macrogol 3350 treatment reduces anal sphincter relaxation compared to combined oxycodone and naloxone tablets

Background Opioid analgesics inhibit anal sphincter function and contribute to opioid-induced bowel dysfunction. However, it is unknown if the inhibition can be reduced by opioid antagonism with oral naloxone, and how this compares to osmotic laxative treatment. Aims To compare the effects of oxycodone and macrogol 3350 treatment (OX + PEG) versus combined oral oxycodone and naloxone (OXN) on anal sphincter function and gastrointestinal symptoms. Methods A randomised, double-blind, crossover trial was conducted in 20 healthy, male volunteers. Participants were randomised to five days treatment of OX + PEG or OXN. Anal resting pressure, anal canal distensibility, and rectoanal inhibitory reflex-induced sphincter relaxation were evaluated at baseline and on day 5. The Patient Assessment of Constipation questionnaire (PAC-SYM), stool frequency, and stool consistency were assed daily. Results Sphincter relaxation was reduced after OX + PEG treatment compared to OXN (difference = −17.6% [95% Cl;−25.2, −10.2]; P < 0.001). Anal resting pressure and anal canal distensibility did not differ between the treatments. PAC-SYM abdominal symptom subscale increased during OX + PEG compared to OXN (cumulated score: 3.2±2.3 vs. 0.2±1.8; P =0.002). Number of bowel movements was higher during OX + PEG vs. OXN (5.4±1.5 vs. 4.2±1.2; P = 0.035), but there was no difference in stool consistency (3.5±0.5 vs. 3.2±0.4; P = 0.14). Conclusions Sphincter relaxation was significantly reduced after OX + PEG compared to OXN. Evaluation of the rectoanal inhibitory reflex may serve as an important objective measure in future trials on treatment of opioid-induced bowel dysfunction.