Assessment of sphincter muscle function before and after posterior sagittal anorectoplasty using a magnetic spinal...

The authors used a magnetic spinal stimulation technique to assess both the preoperative sphincter function and the effect of operative intervention on the sphincter muscle in patients with anorectal malformations.

The authors examined 5 patients with an anorectal malformation consisting of 4 high-type cases and 1 intermediate-type case, that all had undergone posterior sagittal anorectoplasty during the previous 2-year period. Control data also were obtained from 11 age-matched healthy children. A contraction of the external anal sphincter (EAS) was evoked by magnetic stimulation of the sacral roots with a figure-of-eight coil at the level of the lumber and sacral segments. EAS electromyograms then were recorded at the anal verge.

The preoperative motor latencies at L4 stimulation increased significantly more in the patients than in the controls (5.9 +/- 0.5 msec v 4.1 +/- 0.7 msec during left side recording). In the postoperative examination (1 to 5 months after operation), the mean maximum amplitude decreased slightly without any significant difference, where as the latency was almost identical to the preoperative data.

These results suggest that the neurologic function of EAS was congenitally disturbed, and the current operative technique had no significant effect on the sphincter function.