Therefore, though there is loss of power of the sphincter ani muscle, yet in this injury the woman may not suffer any of the consequences of loss of power in the support of the pelvic floor, such as vaginal and uterine prolapse.
After laceration of the perineum through the sphincter ani the divided muscle retracts so that it embraces only the posterior margin of the anus. If the injury be not repaired immediately, retraction and atrophy progress, so that in time the sphincter muscle, lying posterior to the anal opening, may be but half an inch in length and of very much less than its normal thickness. Cicatrization takes place, and the parts present the appearance shown in [Fig. 37].
Notwithstanding the atrophy and retraction of the muscle, continence may be re-established by operation, though many years may have elapsed since the receipt of the injury.
Notwithstanding the very obvious reasons for the performance of the immediate operation for the relief of this condition, it is yet very often neglected, and the gynecologist is called upon to repair the injury many years after its occurrence.
The important part of the operation for this injury consists in the repair of the muscle. In many operations the recto-vaginal septum is repaired and the cutaneous portion of the perineum is repaired, but the operator fails to secure in his sutures the sphincter ani muscle, and consequently the incontinence is not cured (see [Fig. 36]). The mistake often made is that the sutures that are introduced to close the anterior margin of the anus are inserted too far forward and too far out to catch the ends of the sphincter ani muscle, which has retracted so that, in some cases, it lies altogether behind the anal opening. Or, perhaps, only the outer fibers of the sphincter ani are included in the suture, and partial incontinence results.
Fig. 36.—Imperfect repair of the sphincter ani. The muscle has not been included by the sutures, and does not surround the anal opening.
The position of the sphincter ani muscle is indicated by the corrugated or wrinkled skin overlying it. The ends of the muscles, being retracted, do not lie in the plane of the laceration, but their position is marked by a depression or dimple ([Fig. 37]).
The technique of the primary operation is included in a consideration of that of the secondary operation, the only difference being that in the latter operation denudation is necessary.
The parts should first be denuded, so that they present the same raw surface that was exposed in the original laceration.