ENDOLUMINAL ULTRASOUND IS PREFERABLE TO ELECTROMYOGRAPHY IN MAPPING ANAL SPHINCTERIC DEFECTS

Assessment of complex sphincteric defects in patients with fecal incon tinence by digital rectal examination and intraoperative dissection ca n be difficult in the presence of excessive scarring. Adjunctive inves tigation such as endoluminal ultrasound (ELUS) and needle electromyogr aphy (EMG) may provide objective evidence of the nature and extent of the sphincteric defects. In a series of 11 patients, ELUS of the anal canal with a 10-MHz transducer (focal zone of 1-4 cm) accurately detec ted defects in the external anal sphincter (EAS) in seven of seven pat ients, defects in the internal anal sphincter (LAS) in eight of eight patients, and integrity of both sphincters in two patients. These find ings were confirmed by needle EMG of the EAS alone in five patients, b y operative findings at a perineal sphincteroplasty operation in six p atients, and by both in two patients. ELUS was associated with less pa in than was needle EMG (pain score 4 vs. 10, 10 being most painful) an d provided high-resolution radial images of both the EAS and the IAS. Thus, ELUS seems preferable to EMG in mapping anal sphincteric defects and can be a useful anatomic adjunct to physiologic studies of anorec tal function in patients with fecal incontinence.