Successful management of rectovaginal fistula treated by endorectal advancement flap: report of two cases and literature review

Introduction Rectovaginal fistula (RVF) sometimes has a difficulty in treatment. This report describes two patients who suffered from RVF. Case descriptions One patient was a 76-year-old woman who had a RVF over 30 years after the 3rd childbirth. She underwent endorectal advancement flap (ERAF). She had a nighttime soiling after ERAF once a month, which disappeared one year after surgery. Second patient was a 23-year-old woman who had a RVF one month after the first childbirth. She underwent ERAF, and did not have any complications. Discussion and evaluation Both patients did not develop recurrence for four years. Quality of life after ERAF was satisfactory in both patients. ERAF is a safe procedure in terms of both short and long outcomes. We also present a review of the literature concerning ERAF for RVF. Conclusions ERAF can be a potential option as a treatment for RVF.


Background
There is a low incidence of rectovaginal fistula (RVF) in developed countries. RVF sometimes occur after childbirth (Lowry et al. 1988;Rothenberger et al. 1982;Wise et al. 1991) and is sometimes difficult for cure. Endorectal advancement flap (ERAF) is one of options as a treatment for RVF in the world. We herein describe two patients with RVF who were successfully treated by ERAF. To our knowledge, this is the first reported cases of RVF treated by ERAF in Japan. In addition, we report a review of the literature concerning ERAF for RVF.

Patient 1
A 76-year-old woman with RVF was referred to our hospital. She suffered from RVF over 30 years after the third childbirth. A fistula was found at the level of dentate line by the anoscope examination. Similarly, colonoscopy also showed a fistula at the same level ( Figure 1). She underwent ERAF under the diagnosis of RVF (Figure 2a). She was placed at the jack-knife position. The procedure of ERAF was same as previously mentioned (Rothenberger et al. 1982). In short, a four-centimeter-long flap which consisted of mucosa, submucosa, and circular muscle was outlined around the fistula (Figure 2b). The base was two times as wide as the apex of the flap for adequate blood supply. After the resection of the fistula, circular muscle was sutured by horizontal mattress manner (Figure 2c). The flap was advanced over the repaired area ( Figure 2d). She had a good postoperative course and was discharged from hospital on the 7th postoperative day. She had a nighttime soiling once a month, but it disappeared one year after surgery.

Patient 2
A 23-year-old woman with RVF was referred to our department during the second pregnancy. She suffered from RVF after the first childbirth. After the second childbirth via Caesarean section, contrast radiography showed the discharge from anal canal to vagina (Figure 3).  Rectovaginal fistula is seen from the anus (a). The flap of mucosa, submucosa, and circular muscle is raised (b). Circular muscle is sutured by horizontal mattress manner (c). The flap is advanced over the repaired area (d). The flap is sutured in place at its apex and along its sides. She underwent ERAF and had a good postoperative course. She was discharged from hospital on the 7th postoperative day. She did not have any complications.

Discussion
The incidence of RVF in developed counties is low, but RVF is sometimes refractory.
The incidence of RVF after vaginal delivery is 0.1% to 0.5% (Goldaber et al. 1993;Venkatesh et al. 1989). RVF at the lower level is usually caused by obstetric events. RVF at the higher level is caused by radiotherapy or rectal surgery in many cases.
Since ERAF for RVF was firstly reported in 1982 (Rothenberger et al. 1982), it has been one of the standard treatments for RVF. This procedure is a modification of mucosal flap reported by Laird (Laird 1948). Complete excision of the fistula tract is important. A flap consists of mucosa, submucosa, and circular muscle in this technique. After excision of the fistula tract, internal sphincter muscle is mobilized. Then, internal sphincter muscle is approximated in the midline without tension. In Japan, there has been no article regarding ERAF for RVF. To the best of our knowledge, this is the first report concerning ERAF for RVF in Japan. We searched the associated articles through Medline using the key words of 'rectovaginal fistula' and 'endorectal advancement flap'. Thirteen English papers were matched (Table 1) (de Parades et al. 2011;Devesa et al. 2007;Joo et al. 1998;Kodner et al. 1993;Loffler et al. 2009;Lowry et al. 1988;Ozuner et al. 1996;Pinto et al. 2010;Rothenberger et al. 1982;Sonoda et al. 2002;Stern et al. 1988;Tsang et al. 1998;Wise et al. 1991). Among these, six papers included the cases of fistul-inano (Joo et al. 1998;Kodner et al. 1993;Loffler et al. 2009;Ozuner et al. 1996;Pinto et al. 2010;Sonoda et al. 2002).
The most frequent cause of RVF was an obstetric event (Kodner et al. 1993;Lowry et al. 1988;Rothenberger et al. 1982;Wise et al. 1991). Recently, RVF associated with Crohn's disease has been increasing (de Parades et al. 2011;Joo et al. 1998;Kodner et al. 1993;Loffler et al. 2009;Ozuner et al. 1996;Pinto et al. 2010;Sonoda et al. 2002). The median age of RVF varied from 30.5 to 45.5 years old. Duration of disease was 12 months to 31.2 months. The average number of procedure was 1.47 (Pinto et al. 2010). Therefore, the recurrence after the treatment for RVF is problematic. The cure rate of RVF was 41% to 91% (de Parades et al. 2011;Devesa et al. 2007;Joo et al. 1998;Kodner et al. 1993;Loffler et al. 2009;Lowry et al. 1988;Ozuner et al. 1996;Pinto et al. 2010;Rothenberger et al. 1982;Sonoda et al. 2002;Stern et al. 1988;Tsang et al. 1998;Wise et al. 1991). Devesa et al. reported that the success rate of ERAF for simple rectovaginal fistula was 100% (Devesa et al. 2007). In the present study, both patients had simple RVF and succeeded in the treatment. Lowry et al. reported that the cure rates in the first, the second, and the third procedures were 88%, 85%, and 55%, respectively (Lowry et al. 1988). Another paper   (Ozuner et al. 1996). Especially, the success rate was lower in patients with Crohn's disease accompanying small intestinal lesion (Joo et al. 1998). Therefore, ERAF is considered useful in patients with simple RVF after obstetric event. Accurate diagnosis is mandatory before surgery. However, contrast radiography for rectovaginal fistula is sometimes difficult, because contrast radiography can only detect high rectovaginal fistulae unless the applicator does not extend the level of the internal anal opening.
There are some limitations in this study. There are a variety of treatments for rectovaginal fistula. Transverse transperineal approach as well as transabdominal approach exists. In some cases, Martius flap can be another option for RVF (Elkins et al. 1990). However, we could not compare these techniques in this study, because of lack of RVF cases.

Conclusions
We experienced two patients with RVF who were treated by ERAF successfully. Simple RVF after obstetric event is considered good indication for ERAF. ERAF can be a potential option for RVF in Japan.