Predictive value of impaired evacuation at proctography in diagnosing anismus

OBJECTIVE. We aimed to determine the positive predictive value of impaired evacuation during evacuation proctography for the subsequent diagnosis of a nismus.. SUBJECTS AND METHODS. Thirty-one adults with signs of impaired evacuation ( defined as the inability to evacuate two thirds of a 120 mL contrast enema within 30 sec) during evacuation proctography underwent subsequent anorecta l physiologic testing for anismus. A physiologic diagnosis of anismus was b ased on a typical clinical history of the condition combined with impaired rectal balloon expulsion or abnormal surface electromyogram. RESULTS. Twenty-eight (90%) of the 31 patients with impaired proctographic evacuation were found to have anismus at subsequent physiologic testing. Am ong the 28 were all 10 patients who evacuated no contrast medium and all I I patients with inadequate pelvic floor descent, giving evacuation proctogr aphy a positive predictive value of 90% for the diagnosis of anismus. A pro minent puborectal impression was seen in only three subjects during proctog raphy, one of whom subsequently showed no physiologic sign of anismus. CONCLUSION. Impaired evacuation during evacuation proctography is highly pr edictive for diagnosis of anismus.