Cinedefecography and electromyography in the diagnosis of nonrelaxing puborectalis syndrome

A prospective study was undertaken to assess the correlation between electromyography (EMG) and cinedefecography (CD) for the diagnosis of nonrelaxing puborectalis syndrome (NRPR). Clinical criteria for NRPR included straining, incomplete evacuation, tenesmus, and the need for enemas, suppositories, or digitation. EMG criteria included failure to achieve a significant decrease in electrical activity of the puborectalis (PR) during attempted evacuation. CD criteria included either paradoxical contraction or failure of relaxation of the PR along with incomplete evacuation. In addition, other etiologies for incomplete evacuation, such as rectoanal intussusception or nonemptying rectocele, were excluded by proctoscopy and defecography in all cases. One hundred twelve patients with constipation, 81 females and 31 males, with a mean age of 59 (range, 12-83) years were studied by routine office evaluation, CD, and EMG. Forty-two patients (37 percent) had evidence of NRPR on CD (rectal emptying: none, 24; incomplete, 18). Twenty-eight of these patients (67 percent) also had evidence of NRPR on EMG. EMG findings of NRPR were present in 12 of 70 patients (17 percent) with normal rectal emptying. Conversely, 14 of 72 patients (19 percent) with normal PR relaxation on EMG had an NRPR pattern on CD. The sensitivity and specificity for the EMG diagnosis of NRPR were 67 percent and 83 percent, and the positive and negative predictive values were 70 percent and 80 percent, respectively. Conversely, if EMG is considered as the ideal test for the diagnosis of NRPR, CD had a sensitivity of 70 percent, a specificity of 80 percent, and positive and negative predictive values of 66 percent and 82 percent, respectively. In summary, sensitivity, specificity, and predictive values of EMG and CD are suboptimal. Therefore, a combination of these two tests is suggested for the diagnosis of NRPR.