For third-degree laceration repair, two methods are available to repair the external anal sphincter. The irst is an endto-end technique, which we prefer, and is shown in Figure 27-17. Initially, the cut ends of the external anal sphincter, which often retract, are isolated and brought to the midline. Importantly, the strength of this closure is derived from the connective tissue surrounding the sphincter-often called the capsule-and not the striated muscle. Thus, serial interrupted
FIGURE 27-17 In overview, with end-to-end approximation of the external anal sphincter (EAS), a suture is placed through the EAS muscle, and four to six simple interrupted 2-0 or 3-0 sutures of polyglactin 910 are placed at the 3, 6, 9, and 12 o'clock positions through the perisphincter connective tissue. To begin, disrupted ends of the striated EAS muscle and capsule are identified and grasped. The first suture is placed posteriorly to maintain clear exposure. Another suture is then placed inferiorly at the 6 o'clock position. The sphincter muscle fibers are next reapposed by a figure-of-eight stitch. Last, the remainder of the fascia is closed with a stitch placed anterior to the sphincter cylinder and again with once placed superior to it. (Reproduced with permission from
Kenton K, Mueller M: Episiotomy and obstetric anal sphincter lacerations. In Yeomans ER, Hofman BL, Gilstrap LC III, et al (eds): Cunningham and Gilstrap's Operative ObstetriCS, 3rd ed. New York, McGraw-Hili Education, 201o7.) sutures incorporate sphincter fibers and perisphincter connective tissue, to bring sphincter ends together. here are few evidence-based data to guide suture selection for sphincter repair, but delayed-absorbable material can provide sustained tensile strength during healing. This theory is supported by the above study by J all ad and coworkers (2016), which showed higher perineal breakdown rate following OASIS repair with chromic gut.
With the overlapping technique, the ends of the external anal sphincter are brought to the midline and lie atop one another. This method is only suitable for type 3c lacerations-those involving the external and internal anal sphincter. Two rows of mattress sutures travel through both sphincter ends to recreate the anal ring. In comparing the two methods, neither yields superior long-term anatomical or functional results (Farrell, 2012; Fernando, 2013; Fitzpatrick, 2000). Also with type 3c lacerations, the lAS is repaired before the EAS and is described next.
With fourth-degree laceration repairs, the torn edges of the rectal mucosa are reapproximated (Fig. 27-18). At a point 1 cm proximal to the wound apex, sutures are placed approximately 0.5 cm apart in the rectal muscularis and do not enter the ano rectal lumen. Clinicians oten use 4-0 polyglactin 910 or chromic gut for this running suture line. Some recommend a second reinforcing layer above this (Hale, 2007). If this is not done, then the next layer to cover the anorectal mucosa is formed by reapproximation of the internal anal sphincter. his running, nonlocking closure is completed with 3-0 or 4-0 suture (see Fig. 27-18B). Following any repair, needle and sponge counts are reconciled and recorded in the delivery note.