Rectal Atresia and Stenosis
Rectal Atresia
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Rectal atresia and stenosis are defined as the types of defect in which the rectum is found to be blind (atresia) or partially communicating (stenosis) with the distal anal canal.
The atresia site or stenosis is located at the natural limit of rectum and anal canal (immediately above the pectinate line).
The patient is born with a normal-looking external anus. This is the type of defect that is discovered by the nurse who tries to take the temperature in an otherwise normal-looking newborn.
The anal canal is usually not larger than one or two centimeters. The upper blind rectum, usually lying very close to the anal canal, may, however, be separated from it by a very thin membrane, or else by a significant portion of fibrous tissue.
The most conspicuous characteristic of this defect is the fact that these patients have an excellent prognosis, when treated properly, simply because they have all the necessary elements responsible for bowel control.
They have excellent muscles, frequently a normal sacrum, and most importantly, they have an anal canal already located between the limits of the external sphincter with all the nerve endings that will afford the patient normal sensation. Therefore, the anal canal can be split in the middle, but should never be dissected or thrown away.
Previous techniques used by some surgeons included abdominoperineal operations; they frequently resected and did not make use of the original anal canal of the patient. As a consequence, normal sensation, which is essential for achieving normal bowel function, was not preserved.
Rectal Atresia and Stenosis Repair
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In addition, the repair of this defect is relatively simple compared with all the other anorectal defects. Basically, it consists of a posterior sagittal incision dividing all the muscle structures.
Both upper and lower bowel ends are opened and reconnected with a wide anastomosis all muscle structures are then reconstructed meticulously.
The incision is the same as the one used in cases of full Posterior Sagittal Anorectoplasty Posterior Sagittal Anorectoplasty / PSARP. The skin is opened and the incision continues in the subcutaneous tissue, parasagittal fibers, subcutaneous tissue again, and then levator muscle.
Once the levator muscle is open, the upper part of the rectum is also opened and held with sutures placed at the rectal edge. The anal canal is also opened and the fibrous tissue separating both structures can be seen.
The pectinate line is easily identified in the upper portion of the distal anal canal (distal pouch). A simple end-to-end anastomosis with interrupted long-term absorbable sutures is carried out. Also, a Heinecke-Mickulicz type of rectoplasty can be done for the bowel closure in order to avoid a stricture.
Once the rectum is closed, the levator muscle is resutured behind it and. The rest of the layers of the incision are meticulously reapproximated with the help of the electrical stimulator to find corresponding muscles and suture them together with long-term absorbable fine sutures.
The technique in cases of stenosis is basically the same, but rather than anastomosis, we perform only a simple rectoplasty to widen the stricture site.
Results obtained in these patients have been excellent. The operation does not last more than one and a half or two hours. Abdominoperineal approaches for this type of defect, therefore, should be condemned.
These patients, however, still require a period of anorectal dilatations because they may show a tendency to stricture formation in the surgical area.
