Transanal internal sphincter myomectomy: indications, operative procedure and results

From October 1, 1981, until December 31, 1991, we performed clinical, radiological, electromanometrical, histochemical and histological diagnostic procedures in 906 patients under 15 years of age, because of several distinct colonic and anorectal disorders. 739 were clinically constipated and in 272 of them hypertonicity of the internal anal sphincter with or without achalasia could be demonstrated by manometry. 121 of these patients were submitted to a posterior, transanal, partially resective internal sphincteromyomectomy, according to a slightly modified classical procedure. Follow-up of our operated patients ranged from 1 month to 9 years, with a mean of 3 years and 2 months and overall satisfactory results in 87.6% based on clinical evaluation. Additionally, 55.4% of the operated patients had early postoperative manometric controls (n = 67) and 77.6% of these (n = 52) accepted a third manometry, in order to evaluate late results of our procedure. We could demonstrate that early postoperative anorectal electromanometry shows a highly significant decrease of the internal anal sphincter pressure correlating with a clinical improvement in 98.5% of these patients (n = 67). Most late postoperative examinations showed recurrent elevation of the manometric internal sphincter pressure parameters, exceeding the mean values of our own normal controls. Nevertheless, clinically 98.1% of these patients had a persistent satisfactory remission of their symptoms, thus not correlating with the manometric findings in these cases. We conclude, that transanal internal sphincter myomectomy is a safe surgical procedure, which leads to satisfactory results in approximately 90% of chronically constipated children with anal sphincter hypertonicity, if very precise indications for operation are considered.