This retrospective study was approved by the Ethics Committee of the Affiliated Hospital of Southwest Medical University. Signed informed consent was obtained from each patient preoperatively. The clinical data of five patients with old fourth-degree perineal tears who were treated between January 2015 and January 2021 were analyzed retrospectively. On admission, physical examination showed that the perineum was looking abnormal; the anus, rectum, and vagina were completely connected, and the anal sphincter was loose and weak (Fig. 1). All patients underwent routine laboratory examinations, colonoscopy, and anorectal manometry (ARM), excluding serious systemic diseases and psychosis.

Fig. 1.

Disappearance of the normal perineal structure, with complete connection of the anus, rectum, and vagina.

All patients took oral intestinal anti-microbial agent drugs (metronidazole tablets, 0.2–0.4 g/tablet, three times/day) 3 days before the operation and consumed a residue-free diet. Intestinal preparation was performed by oral administration of compound polyglycol electrolyte powder 1 day before the operation, and enema was performed once in the evening of the day before and in the morning of the day of the operation. The vagina was rinsed with dilute iodophor 1 day before and on the day of the operation. When the intestine and vagina were fully prepared, antibiotics (cefuroxime) were injected intravenously 0.5–2 h before the operation to prevent infection.

All patients were treated with spinal anesthesia. After satisfactory anesthesia, the bladder lithotomy position was taken, an indwelling catheter was inserted, a routine disinfection towel was placed, an iodophor cotton ball was used to disinfect the lower segment of the vagina, anal canal, and rectum, and a gauze roll was used to fill the anus. The specific instructions were as follows. (1) The operating field was exposed, before separating the labia minora to both sides and sewing them onto the labia majora and medial thigh (Fig. 2); (2) an “X” incision was made, before cutting open the skin and subcutaneous tissue, and freeing it fully as a flap; (3) after local submucosal injection of 1:200,000 U epinephrine, arcuate incision of the rectovaginal septum, separation of the rectovaginal septum, and exposure of the levator ani muscle, the broken ends of the sphincter were freed on both sides; (4) the broken ends of the levator ani and sphincter were sutured, layer-by-layer from top to bottom, and each cavity was closed (the rectal wall and posterior vaginal wall were sutured intermittently); (5) the flap was cross-transferred and then suture to reconstruct the perineal body; and (6) a drainage strip was placed under the skin and an anal tube was inserted in the anus.

Fig. 2.

Operation steps. (A) An “X” incision was made, before cutting the rectovaginal septum, separating the rectovaginal septum, exposing the levator ani muscle, and freeing the broken end of the sphincter to both sides. (B) The broken ends of the levator ani and sphincter were sutured layer-by-layer from top to bottom, and each cavity was closed. (C) Drainage strips were placed subcutaneously and anal tubes were inserted in the anus.

The patients were asked to stay in bed until the sutures were removed. Generally, the suture was removed 8–10 days after the operation. Postoperative defecation was controlled for 5–7 days. Patients fasted for 1–2 days and consumed a residue-free diet for 3–5 days. Patients took a laxative on the 4th day after the operation and it was ensured that loose and soft stool was discharged within 2 weeks of the operation. Patients consumed soft, easily digested, high-calorie food to prevent constipation and excessive force. The catheter was retained for 5–7 days, the anal canal was maintained for as long as possible until defecation, and infection was prevented with antibiotics for 72 h.

One month after the operation, anal function was evaluated based on anal incontinence. Firm and loose stools were cured by self-control; automatic control of dry stool and poor control of loose stool were considered as positive treatment outcomes; and no improvement in defecation was considered as a negative treatment outcome. The shapes of the perineum and anus were visually observed to check if the skin was continuous. ARM and transperineal ultrasonography were performed 3 months after the operation to observe the continuity of the anal sphincter, anal mucosa, and perianal skin. The anal continence was evaluated using the Wexner continence grading system [4] (Table 1), and the score was calculated before the operation and 3, 6, and 12 months after the operation. A Wexner score of 0 indicated normal function, while a score of 20 indicated complete incontinence.

SPSS 25.0 statistical software (IBM Corp., Chicago, IL, USA) was used to conduct statistical analysis. The measurement data are expressed as the mean measurement data ($\overline{x}$$\pm$ m); the t-test was used when the variance was homogeneous, and the t${}^{\mathrm{\prime }}$ test was used when the variance was heterogeneous. p-values 0.05 were considered to indicate statistical significance.

Five patients with old fourth-degree perineal tears with an average age of 56 $\pm$ 5 years (range, 47–61 years) were included. The average course of disease was 26 $\pm$ 9 years (range, 10–32 years). All cases were caused by birth injury and were not repaired on time after delivery, resulting in old grade IV perineal laceration. All patients were operated for the first time.

The mean operative time was 110 $\pm$ 9 min. The estimated blood loss during the operation was 19 $\pm$ 4 mL. No severe adverse events were encountered during the surgeries.

All five patients were followed-up with for 12 months, at which point, anal incontinence was significantly improved, defecation and exhaust could be controlled, and all patients were cured. One month after the operation, the shape of the perineum and anus of the patients was complete, and the skin was well aligned and continuous (Fig. 3). The mean perineal body length was 3.58 $\pm$ 0.43 cm (range 3.1–4.2 cm). ARM was performed 3 months after the operation. The postoperative anal resting pressure (56.20 $\pm$ 3.42 mmHg), maximum anal systolic pressure (90.00 $\pm$ 5.39 mmHg), and maximum anal systolic time (20.80 $\pm$ 3.77 s) were compared to the preoperative values (11.80 $\pm$ 1.79 mmHg, 31.40 $\pm$ 3.21 mmHg, and 8.40 $\pm$ 1.52 s, respectively, and were shown to be significantly different (t = –25.720, p 0.01; t = –20.902, p 0.01; t = –6.826, p 0.01). Three months after the operation, transperineal ultrasonography showed continuity of the anal sphincter, anal mucosa, and perianal skin. The Wexner scores at 3, 6, and 12 months after the operation were 1.00 $\pm$ 0.71, 0.40 $\pm$ 0.55, and 0.20 $\pm$ 0.45, respectively, which were significantly lower than those before the operation (t = 25.560, p 0.01; t = 28.633, p 0.01; t = 30.210, p 0.01).

Fig. 3.

Conditions after the operation. (A) There was no obvious blood and fluid leakage at the incision on the first day after the operation. (B) There was no incision dehiscence after suture removal on the 10th day after the operation. (C) One month after the operation, the shape of the perineum and anus was complete, and the skin was well aligned and continuous.