Background/Aims@#We aimed to evaluate
associations between comorbidities,
peripheral neuropathy , and spontaneous
internal anal sphincter relaxation (SAR) in
patients with defecatory disorders. @*
Methods @#A
patient was considered to exhibit SAR during high-resolution anorectal
manometry (HR-
ARM ) when the nadir
pressure is < 15 mmHg and the
time from onset to
relaxation was ≥ 15 seconds in the resting
pressure frame. A
case-control study was performed using HR-
ARM data collected from 880
patients from January 2010 to May 2015. We identified 23 cases with SAR (median age 75 years; 15
females ; 12
fecal incontinence and 11
constipation ). We compared HR-
ARM values, Charlson index
comorbidity scores, neuropathy, and the
prevalence of
diseases that potentially cause neuropathy between controls and SAR
patients . Each SAR case was compared to 3 controls. Controls were selected to match the age,
gender , and examination year of each SAR case. @*Results@#Compared to controls (26.1%), SAR
patients (52.2%) exhibited a significantly higher frequency of
fecal incontinence . SAR
patients also had higher Charlson index scores (5 vs 4, P = 0.028). Nine of 23 SAR
patients (39.1%) exhibited
peripheral neuropathy — this frequency was higher than that for the
control group (11.6%; P = 0.003).
Diseases that potentially cause neuropathy were observed in 17 of 23 SAR cases and 32 of 69 controls (P = 0.022). @*Conclusions@#SAR develops in
patients with
constipation and
fecal incontinence but is more common in
patients with
fecal incontinence . Our controlled
observational study implies that SAR is associated with
peripheral neuropathy and more severe comorbidities.