Predictive value of internal anal sphincter thickness for diagnosis of rectal intussusception in patients with solitary rectal ulcer syndrome

Abstract

Abstract Background The aim of this study was to determine any association between a thickened internal anal sphincter (IAS) on anal endosonography and high-grade rectal intussusception on evacuation proctography in patients with solitary rectal ulcer syndrome. Methods Anal endosonography was performed in 20 patients with solitary rectal ulcer syndrome and IAS thickness defined as normal or abnormal depending on age. Sphincter thickness was compared with the presence or absence of high-grade intussusception on subsequent evacuation proctography to determine any relationship between the two. Results Thirteen patients had an abnormally thick IAS, two of whom were unable to evacuate. Of the remaining 11 patients, ten showed high-grade intussusception (positive predictive value 91 per cent). Only three of seven patients with a normal IAS had high-grade intussusception (negative predictive value 57 per cent). Patients with a thick IAS were significantly more likely to have proctographic evidence of high-grade intussusception (P = 0·047). Conclusion Sonographic findings of a thick IAS are highly predictive for high-grade rectal intussusception in patients with solitary rectal ulcer syndrome.