Treatment of Rectovaginal Fistula

Abstract

Rectovaginal fistula (RVF) is a challenging complication with unsatisfactory success and a significant burden for the patients. With insufficient clinical data due to the rare entity, the present state of treatments for RVFs was reviewed especially form the point of factors to determine management, classifications, principle of treatment, conservative and surgical treatments with outcomes. Size, fistula localization and etiology, type of fistula; “simple” or “complex,” status of anal sphincter complex and surrounding tissue, presence or absence of inflammation, presence of diverting stoma, previous attempted repair and radiation therapy, patient's condition with co-morbidities, and surgeon's experience are important factors to determine the management of RVF. The inflammation should initially subside in cases with infection. Starting with conservative surgical options and interposing healthy tissue for complex or recurrent fistulas, invasive procedures will be performed if conservative treatment failed. Conservative treatment may be effective in RVFs with minimal symptoms and should be done for small RVFs for a 36 months usual period. Anal sphincter damage might need a repair of sphincter muscles along with RVF repair. Diverting stoma can initially be constructed in patients with severe symptoms and larger RVFs to relief the patient's pain. Simple fistula is usually indicated for local repair. Local repairs to transperineal and transabdominal approaches can be used for complex RVFs. Interposition of healthy, well-vascularized tissue can be required for more complex fistulas and abdominal procedures for high RVFs.

Introduction

Rectovaginal fistula (RVF) is defined as an epithelium-lined abnormal communication between the rectum and vagina[1,2]. RVF generally presents with passage of air and stool from the vagina resulting to the patient's psychological burden secondary to recurrent urinary tract and vaginal infections[1]. The low success rate with a wide range of success and remained common recurrence makes RVF treatment a surgical challenge[1-8]. Furthermore, in patients with previous attempt at repair, low success rate is reported after further surgery[3-8]. RVF optimal treatment options inconclusively determined due to the limited case number and lack of enough evidence, comparison, and randomized studies[9]. Hence, the present state of treatments for RVFs was reviewed especially from the point of factors to determine management, classifications, principle of treatment, and conservative and invasive treatments with outcomes.

Factors to Determine Management

The size, fistula localization and etiology, fistula type: “simple” or “complex,” anal sphincter complex and the surrounding tissue status, presence or absence of inflammation, presence of diverting stoma, previous attempted repair and radiation therapy, patient's condition with co-morbidities, and surgeon's experience are important factors to determine the management of RVF[1,2,10,11]. These factors have to be clearly investigated before choosing treatment options. The anal sphincter damage might need a sphincter muscles repair aside from RVF repair; draining the inflammation before RVF repair is required in case of inflammation.

Classification

RVF is generally classified according to the size, localization, etiology and type of fistula; “simple” or “complex”[1,2,10,11]. These basic classifications help in selecting conservative treatment or optimal surgical procedure for the patient with RVF.

Size

The diameter of the fistula is classified as small (<0.5 cm), medium (0.5-2.5 cm), and large (>2.5 cm) (Table 1)[12,13]. Small RVF can be a candidate in initial conservative treatment[2]. Reports on local RVFs repairs include small fistulas or with unknown size[7,14-19].

Table 1.

Classification of Rectovaginal Fistula.

1. Size [12]

・Small: <0.5 cm

・Middle: 0.5–2.5 cm

・Large: >2.5 cm

2. Location

1) According to surgical approach [1,12]

・High: transabdominal approach is required

・Middle: in between high and low

・Low: correction by anal, perineal, and vaginal approach

2) According to anatomical location

From vaginal side [2,20]

・ High: the fistula is in the area of the posterior vaginal fornix

・Middle: from the level of cervix to just superior to fourchette

・Low: vaginal opening near the posterior fourchette

From anorectal side [21]

・ High: rectal origins proximal to the anorectal sphincter complex

・Low: originate distally from the anal sphincter complex

From anorectal and vaginal side [8,11,22,23]

・ High: a tract connecting the upper vagina with the rectum

・Middle: a tract that lies in between these levels

・Low: a tract between the distal anal canal and the inside of the posterior fourchette

[Reference]

Localization

The localization of RVF is mostly classified via anatomical location or surgical approach (Table 1). Based on surgical approach, low fistulas are those reconstructed via anal, perineal, or vaginal access, while high fistulas require an abdominal approach[1,12]. In anatomical location, when the site of RVF is determined from the vaginal side, low RVF classifies as a fistula with vaginal opening near the posterior fourchette, high RVF in the area of the posterior vaginal fornix, and middle RVF from the level of cervix to just superior fourchette (Table 1)[2,20]; when the site of RVF is determined from the anorectal side, low RVF originates distally from the anal sphincter complex, and high RVF with rectal origins proximal to the anorectal sphincter complex[21]. According to classification with anatomical location from the anorectal and vaginal side, “low” RVF may be classified as a fistula with a tract between the distal anal canal (at or below the dentate line) and inside of the posterior fourchette; “high” RVF with a tract connecting the upper vagina (at the level of the cervix) and the rectum; and “middle” RVF with a tract that lies in between these levels[8,11,22,23]. In this classification, the terminologies “anovaginal fistula” and “low-rectovaginal fistula” may be interchangeably used[11]. Clarifying the role of anal sphincter complex can be necessary in classifying the site of RVF because repairing sphincter defect influences outcomes in RVF repair[4]. Transabdominal repair is often used for anatomically classified high RVFs.

Etiology

There are various causes for RVFs (Table 2), including obstetric trauma (85%) and pelvic surgery (5%-7%)[1,10]. Inflammatory bowel disease, especially Crohn's disease, malignancy, and radiation are also predominating causes of RVFs. The respective reported cause of RVF incidence depends on the institute or hospital; however, obstetric injury was the most predominant in many reports[7,8,13,16,17,22]. Among these causes, radiation-induced and Crohn's-related and malignancy associated RVFs are more problematic, resulting in poorer success in treatments[1,8,21].

Table 2.

Etiology of Rectovaginal Fistula.

・Trauma:

1) Obstetric (Delivery injury)

2) After surgery: post-LAR, post-pouch surgery, post-pelvic organ prolapse surgery (TVM etc.), post-hemorrhoid surgery (PPH), post-local excision, etc.

3) Intercourse injury, foreign body, etc.

・Inflammatory bowel disease: Crohn’s disease, etc.

・Pelvic irradiation

・Neoplastic: Rectal, gynecological, hematologic

・Infection: Anal gland, Bartholin gland abscess

・Congenital

・Miscellaneous

LAR: low anterior resection, TVM: tension-free vaginal mesh, PPH: procedure for prolapse and hemorrhoids

Type of fistula, “Simple” or “complex”

This classification can be used in selecting surgical repair or approach for RVF[10,11]; however, the definition varies depending on literature[3,6,10,11,23-26]. Lowry et al. defined simple RVFs as <2.5 cm in diameter, low or mid-vaginal septum in location, and infectious or traumatic in origin[3]; El-Gazzaz et al. defined simple RVFs to have a low, small diameter (<2 cm) communication between the anal canal and vagina and typically result from obstetrical injury or infection[23]. “Complex” RVFs involve a higher tract between the rectum and vagina, are of larger diameter, or result from radiation, cancer, or complications of pelvic surgical procedures[6,11,24-26]. Other literatures define the difference of these RVF on whether it will be amenable to a local repair vs. a more complicated underlying pathogenesis that will require resection, interposition grafts, and/or diversion[10]. Concretely, a “simple” RVF can be defined as a fistula with size approximately <2.5 cm, more distally located along rectovaginal septum, and generally occurred a result of obstetric trauma or a cryptoglandular infection. Meanwhile, “complex” fistulas typically result from inflammatory bowel diseases, radiation, invasive cancer origin, and fistulas with failed attempted repair, which are more proximally located on the rectovaginal septum (Table 3)[10]. While “simple” RVF will be amenable to a local repair, “complex” RVF will require resection, interposition graft, and/or diversion[10]. The success rate of “complex” RVFs is poorer than that of “simple” RVFs even in previous cases with fail attempted repair[19].

Table 3.

Type of Fistula “Simple” or “Complex”.

Factors	Simple*	Complex*
Size	smaller	larger
Localization	low	high
Etiology	obstetric trauma or cryptoglandular infection	inflammatory bowel diseases, radiation, or invasive cancer
Others		failed attempted repair

*“Simple” RVF includes all factors, and “Complex” RVF either of the factors.

Principle of Treatment

After determining the factors for treatment, the initial management of RVFs is non-operative, conservative treatment[3,11,27]. The inflammation should subside in cases with infection[11]. Inducing remission prior to RVF repair[10,28-32] is essential in patients with Crohn's disease. Starting with conservative surgical options and interposing healthy tissue for complex or recurrent fistulas will be performed if conservative treatment failed[10]. Diverting stoma can initially be constructed in patients with severe symptoms and larger RVFs to relief the patient's pain[6,13,33,34].

Conservative Treatment (Table 4)

Table 4.

Summary of Outcomes of Conservative/Endoluminal Treatments for RVFs.

Methods	Reference	n	Etiology	Success rate	Follow-up
Conservative
	[11,36-38]	14.1%–18% of all RVFs	52%–66% of various conservative cases
	[2,47]	24.6% (14/57) of all RVFs	post-LAR	71% (10/14) of various conservative cases
Infliximab	[50]	29	Crohn	60.7% (17/28)	10 weeks
				44.8% (13/29)	14 weeks
Infliximab	[51]	14	Crohn	14%	4–6 weeks
Self-expandable	[53]	10	post-LAR	80% (8/10)	24 months
metallic stents
Endoluminal clipping	[55]	16	various	43.7% (7/16)	8 months
Fibrin glue	[60]	39	various	31% (12/39)	-

LAR: low anterior resection, Crohn: Crohn’s disease, [Reference]

Conservative treatment may include baths, wound care, debridement―as needed, antibiotics―in cases of infection, and stool-balking fiber supplements for a 3-6 months usual period[11,27,35]. Among patients with RVFs originating from various etiology, mainly from obstetric trauma, 14.1%-18% of patients have been initially managed conservatively; otherwise, surgical treatments were performed[36,37]. The healing rate of conservative treatment ranged 52%-66%[11,36-38]. Conservative therapy should be used for small RVFs[36,37]. Oakley reported that almost half (45%) of treated RVFs were expectantly small (<0.5 cm)[36]. Successful therapy by hyperbaric oxygen is documented only in two patients with obstetric-related RVF[39].

RVFs after low-anterior resection (LAR)

RVF after LAR is usually refractory to conservative treatment[2,26,40,41]. Conservative treatment might only be effective in RVFs with minimal symptoms (e.g., only passage of flatus but not feces per vagina) and no pelvic radiation[2]. RVFs after LAR are usually managed by bowel rest and total parenteral nutrition up to 2 months before the RVFs spontaneously heals to <1 cm[2,42,43]. However, these healed cases were reported only as case reports[42,43]. The documented case reports in using vaginal or oral estriol tablet in addition to conservative therapy resulted in the closure of RVFs[44-46]. Summarizing the successful case reports after LAR, vaginal estriol tablet was given in eight patients without surgical intervention, and six of eight RVFs healed within 35 days. Meanwhile, oral estriol tablet was given in two patients without surgery, and RVFs healed within 26 days[45]. Oral or vaginal estriol table was given in four patients with surgical intervention (three diverting stomas), and RVFs healed in 16-120 days post-management[45]. A survey of active members of the American Society of Colon Rectal Surgeons (ASCRS) in the 1990s identified that 14 of 57 RVFs after LAR (24.6%) were managed conservatively, and 71% (10/14 cases) healed conservatively[2,47].

RVFs induced by Crohn's disease

Treatment options in patients with Crohn's disease induced RVFs range from observation to medical therapeutics to the need for surgical intervention[48]. Current medications targeting Crohn's disease include antibiotics, corticosteroid, immunomodulators, and biologics. Metronidazole has been reported to successfully treat RVF[32,48,49]. Sands et al.[50] reported in the ACCENT II study that after infusions of infliximab at weeks 0, 2, and 6, 60.7% (17 of 28) and 44.8% (13 of 29) of RVFs were closed at weeks 10 and 14. Concurrently, Parsi et al.[51] documented the rate of complete response to infliximab was significantly lower among 14 patients with RVF (14%) compared to those with perineal fistula (78%) at 4-6 weeks follow-up. Association of Coloproctology of Great Britain and Ireland consensus exercise advocates the use of anti-tumor necrosis factor α (TNFα) therapy[29]. Recent review shows the overall response rates of RVF to medical therapy were 38.3% complete response (fistula closure) and 22.3% partial response, and the response rates to anti-TNFα therapy were 41.0% complete response and 21.8% partial response, respectively[30].

Nine patients with one or more unsuccessful medical and/or surgical treatments for Crohn's disease induced RVFs received hyperbaric oxygen therapy; however, clinical closure occurred in none of the patients at 3-month follow-up[52].

Endoluminal Procedures, Fibrin Glue, Plug and Others (Table 4)

Self-expandable metallic stents have been used for RVFs after colorectal resection for cancer[53,54]. The RVF healed in 8 of 10 patients (80%); however, some of the patients experienced stent dislodgement or severe tenesmus requiring stent removal[2,53].

Endoluminal clipping of RVFs by using over-the-scope clip proctology system resulted in healing of the fistula in 7 of 16 patients (43.7%) with various etiology at eight months after treatment; however, 11 patients had a temporary diverting stoma at time of the clipping procedure[55]. A technique of combination of endoscopic stent with endovaginal clipping was also reported[56].

Two of five (40%) RVFs were successfully treated with transanal endoscopic surgery[57]. Recent review of endoscopic repairs of RVF by Zeng et al.[58] includes 71 patients in 11 articles. The causes of RVFs were post-surgery in 51 patients (71.8%), obstetrics in 7 patients (9.8%), and inflammatory bowel disease in 5 patients (7%). Most fistulas are located in low or mid-location. Success rate of endoscopic repairs, including clipping, stenting, and transanal endoscopic microsurgery, ranged 40%-93% at follow-up of >1-year.

Fibrin glue application has been performed for RVFs with various etiology[59,60]; however, durable healing was only achieved in 31% of patients (12/39)[60]. Fistula plug has shown some benefit to the perineal fistulas of cryptoglandular origin; however, the limited data for RVFs has shown only a 20%-50% closure rate[9,10].

Stem cells therapy emerged as a treatment for Crohn's-related RVFs[61,62]. Initial study demonstrated a 60% of success rate at 12 weeks after administration[61]; however, recent review showed a lower healing rate of 27.2% for RVFs compared with 78% and 76.4% for perianal and transsphincteric fistulas, respectively[62].

Surgical Treatment (Table 5, 6)

Table 5.

Surgery for RVFs and Main Indications.

Method	Main indication
Stoma
Fecal diversion alone	small fistula
Stoma with RVF repair	large fistula and burden on the patient
Local repair without tissue interposition
Advancement flap	low-lying/simple traumatic RVFs
Episioproctotomy	obstetrical or cryptoglandular RVFs with sphincter defect
Transverse transperineally repair	complex, recurrent and larger RVFs
Fistulectomy and closure	small/low-lying RVF, especially obstetric origin
Local repair with tissue interposition	complex, recurrent, or persistent RVFs
Martius flap	low and mid-level fistulas up to approximately 5 cm
	proximal to the vaginal introitus
Gracilis muscle flap	refractory, recurrent RVFs, especially secondary to Crohn’s disease and after pelvic surgery
Levator ani muscles interposition	low and mid-level simple and complex RVFs small to middle size
Abdominal repair	high RVF not amenable to trans-perineal repair
Fistula excision and closure with omentum interposition	tissues surrounding the fistula has minimal fibrosis, good blood supply, no infection, and no evidence of cancer recurrence
Rectal resection	possibility of multiple adhesions and difficult pelvic dissection

Table 6.

Summary of Outcomes of Surgical Treatments for RVFs.

Method	Reference	n	Etiology	Success rate	Follow-up
Stoma alone	[2,6,40,41,47,54]	-	post surgery	25%–100%	various
Advancement flap	[11,19,63,64,69-71]	-	various	41%–78%	various
	[16,28,32,72]	-	Crohn	33%–83%	various
Episioproctotomy	[8,11,19,22,23,75-79]	-	mainly obstetric & cryptoglandular	78%–100%	various
Advancement flap	[77]	37	obstetric &	62.2% (23/37)	mean 49 months
Episioproctotomy		50	cryptoglandular	78% (39/50)
Transperineal repair	[10,18]	-	various	64.7%–100%	various
Advancement flap	[69]	37	various	78.4%	3 months to
Transperineal repair		34		64.7%	9.5 years
Fistulectomy*	[36,71,81-83]	-	mainly obstetric	53.1%–100%	various
Martius flap	[9,10,84-87]	-	various	65%–100%	various
Gracilis muscle	[92]	106	various	33%–100%	median 21 months
interposition
Anterior	[13]	16	various	100%	median 84 months
levatorplasty**
Abdominal approach
Fistula excision and closure***	[96]	40	various	90%	median 28 months
Redo coloanal anastomosis	[41]	7	after LSR	85.7%	-
Flap procedures	[71]	38	various	57.9%	median 6 months
Abdominal resections		29		55.2%
Primary closure with sphincter repair		32		53.1%
Plug and fibrin glue		22		18.2%

* Fisturectomy and closure with or without sphincter repair or tissue interposition,

** Transvaginal anterior levatorplasty,

*** Fistula excision and closure with omentum interposition,

LAR: low anterior resection, [Reference]

Numerous surgical techniques have been described for RVFs through various approaches: transanal, transperineal, transvaginal, and abdominal approach. After identifying the factors to determine the management, the first step includes controlling any sepsis by draining abscess and/or seton placement[28]. ASCRS clinical practice guidelines strongly recommend the use of a drainage seton to facilitate resolution of acute inflammation or infection associated with RVFs as low-quality evidence[11]. Simple fistula is usually indicated for local repair. Local repairs to transperineal and transabdominal approaches can be used for complex RVFs. Interposition of healthy, well-vascularized tissue can be required for more complex fistulas such as those secondary to radiation[28].

The period <9 months between diagnosis and first surgery is reported to be one of independent factors for success[63]. About half of patients with RVFs need multiple surgery[13]. Halverson et al. reported that 79% (27/34) of patients eventually healed after a median of 2 operations[64]. RVFs in Crohn's disease often need surgical intervention, and the response to a combination of medical and surgical treatment was 44.2% though the overall response rates to medical therapy was 38.3%[30].

1. Stoma

Diverting stoma can diminish symptoms of RVF and might help fistula healing. Corte et al. described that temporary transversal stoma significantly increased the success rate of repair[63]. Meanwhile, Lambert et al. found in their retrospective study that stoma did not help to improve the recurrence rate after RVF repair[65]. Due to insufficient proof, the clinical effectiveness of diversion stoma remains controversial[66]. German S3-guideline for rectovaginal fistula commented with strong consensus that the decision regarding stoma creation should primarily base on the extent of the local defect and the resulting burden on the patient[1].

Stoma for RVFs after surgery

Diverting stoma have been used either as stoma with conservative therapy or with RVF repair. Prophylactic diverting stoma is often constructed in patients with low colorectal anastomosis[2,6,13,40]. In patients without initial diverting stoma for colorectal anastomosis, fecal diversion alone has resulted in the closure of RVF in 25%-100%[2,6,40,41,47,54]. Barugola et al. reported that half of the RVFs healed within six months after the construction of a diverging stoma; the failed factors after fecal diversion alone were large fistula and the presence of pelvic sepsis[34]. Komori et al. classified RVFs into four types: “Alone type,” “Dead space type,” “Anastomotic stricture type,” and “Dead space and Anastomotic stricture type” according to the diagnostic imaging, and 71.4% (5/7) of patients with “Alone type” RVF healed with only diverting stoma[67].

2. Local repairs

The approaches to local repair include transanal (endorectal), transperineal, and transvaginal techniques with or without tissue interposition.

Local repair without tissue interposition

1) Advancement flap

Advancement flap (AF) may be performed by raising either rectal or vaginal mucosa and using it to cover the fistulous tract[2]. This is performed in conjunction with debridement/excision of the fistula tract and primary closure[10]. Several merits have been listed according to approaches in AF: endorectal or transvaginal. While endorectal AF can be performed from high pressure side with easier mobilization of the mucosa, transvaginal AF might have a merit of providing a better vascularized tissue with easier recovery etc.[10]. AF is usually a procedure of choice for low-lying/simple traumatic RVFs without a history of incontinence[9,10]. AF also has been used for complex RVF including Crohn's disease[11,16,31,32,68]. Mac Rae et al. reported that AF for RVF is generally not recommended for persistent complex fistulas or for simple fistulas with previous failed repair by AF repair[19]. Hannaway et al. stated that endorectal AF in patients with Crohn's disease is contraindicated both in women with extensive ulceration or stricturing of the anal canal and transitional zone and women with anterior sphincter defect[48], although this technique is ideal for patients with minimal disease or normal anal canal[32,48]. Endorectal AF can be performed in combination with sphincteroplasty in patients with sphincter damage/defect and fecal incontinence. Endorectal AF with or without sphincteroplasty is strongly recommended as the procedure of choice for most patients with RVF by ASCRS clinical practice guidelines[11].

The success rate of endorectal AF for RVFs with various etiology ranges 41%-78%[11,19,63,64,69-71]. Crohn's disease has been implicated as a significant risk factor for failure, associated with inferior outcomes (33%-83%)[16,28,32,72] and recurrence[73]. The success rate of repeat flaps for failed attempt at fistula repair has been documented in 55%-93%[3,64,74]. Higher success rate has been reported by adding sphincteroplasty on endorectal AF in patients with RVF and incontinence and/or sphincter damage[3,4,17,63,70].

2) Episioproctotomy

Episioproctotomy is one of the transperineal procedures. All tissue above the fistula, including anterior sphincter complex and rectovaginal septum, is cut and then reconstructed in layers with fistulotomy during episioproctotomy. This procedure can be suitable for patients having obstetrical or cryptoglandular RVF with anterior sphincter defect[11]. Success rate ranges 78%-100% with acceptable fecal and sexual function[8,11,19,22,23,75-79]. A slightly or significantly better healing rate has been documented in episioproctotomy than that in the other procedures for RVF secondary to cryptoglandular or obstetrical origin[23,77]. The risk of this procedure is wound healing.

3) Transverse transperineal repair with or without sphincteroplasty

This procedure can be called as transperineal repair or transperineal approach[28,69]. This procedure approaches the fistula tract through the perineum. Transverse incision through the perineal body is initially performed, followed by dissection of rectovaginal septum cephalad to the fistula tract. After excising the fistula tract, multiple closure is accomplished with or without sphincteroplasty or levatorplasty[10,32]. This procedure allows good exposure of the fistula and enables tissue interposition and is indicated for more complex, recurrent, and larger RVF[28]. This procedure is best used in women with pre-existing incontinence, or those a history of failed transanal or transvaginal approach[10,21]. Reports show 64.7%-100% success rate[10,18]. A poorer healing rate is documented in transperineal repair with levator interposition compared with endorectal AF for RVF with mixed etiology (64.7% vs. 78.4%, respectively)[69]. Recent report by Zhou et al. indicates that group undergoing transperineal repair with stapling showed better postoperative Wexner score, less intercourse pain, and lower recurrence rate (6/45 vs. 17/37) than group undergoing transperitoneal direct suturing for low- and mid-level RVF[80].

4) Fistulectomy and closure with or without sphincter repair or tissue interposition

This procedure may be reported as purse-string repair[81], fistulectomy with or without sphincter repair or tissue interposition[36,82] or primary closure with sphincter repair[71]. This can be performed to RVF secondary to Crohn's disease[15] by any approach but vaginal approach is most preferred by gynecologists[81-83]. This procedure includes excision of the fistula tract followed by multiple closure[83]. Sphincter repair may be added in patients with fecal incontinence or sphincter damage[71,82]. This procedure is indicated for small/low-lying RVF, especially obstetric origin[81,82]. Success rate of this procedure ranges 53.1%-100%[36,71,81-83].

Local repairs with tissue interposition

The use of tissue interposition along with local repair improves the healing of RVF repair by inserting well-vascularized tissue into the rectovaginal septum. Tissue interposition enables to separate and protect the vaginal from the rectal suture. Generally, these procedures are most suitable for complex, recurrent, or persistent RVFs.

1) Martius (bulbocavernosus) flap

This procedure can be called as bulbocavernosus muscular fat pad or Martius labial fat pad[2,28]. After separating the rectum and vagina through a perineal dissection, pedicle muscular graft from the labia majora is transposed to the perineal wound between the rectum and vagina[84]. Low- and mid-level fistulas up to approximately 5 cm proximal to the vaginal introitus is indicated for this procedure, according to the reach of the pedicle[10]. Though this procedure has been reported in small retrospective studies with various etiology and limited follow-up[11], success rate is reported to range 65%-100%[9,10,84-87]. This procedure is documented to be superior to rectal AF alone[85]. This procedure merits with lower morbidity among tissue interposition procedures[28]. Disadvantage of this procedure is postoperative dyspareunia and labial wound tissue, which are usually resolved with time and local wound care[10,87].

2) Gracilis muscle flap

This procedure is generally much more complex and invasive than that of the Martius flap repair[1]. After harvesting the gracilis muscle from the leg as a proximal pedicle, the gracilis muscle is used as an interposition graft between the rectum and vagina, following direct closure of the corresponding fistula orifices[1,10]. This procedure is usually preceded by a diverting stoma[28,88]. Gracilis muscle flap has been used for refractory, recurrent RVFs, especially secondary to Crohn's disease and post-pelvic surgery[11,73,88-92]. A success rate of 33%-100% has been reported in the review of 17 studies, including 106 patients at a median follow-up of 21 months[92]. Increased postoperative morbidity, including surgical site infection, thigh numbness, hematoma, prolonged decrease in sexual function, and dyspareunia, are the drawbacks of this procedure[1,9,10,89-91].

3) Levator ani muscles interposition

Two procedures: puborectalis sling interposition and transvaginal anterior levatorplasty have been reported as levator ani muscle interposition procedure[7,13]. The etiology of RVFs is various in these reports. A transverse incision with a vertical incision enclosing the RVF is performed in the posterior vaginal wall followed by dissection of rectovaginal septum up to 3-4 cm above the level of the fistula to expose both limbs of the puborectalis and pubococcygeus muscles (Figure 1a). After excising the fistula tract, anterior rectal wall is transversely closed. The puborectalis and pubococcygeal muscles are then brought together by interrupted sutures to cover the fistula tract (Figure 1b), followed by closure of the vaginal wall in transvaginal anterior levatorplasty (Figure 1c). This procedure was performed for low and middle located RVFs up to 2.5 cm in diameter, including 7/16 previously failed attempt at repair. Healing of RVF was accomplished in all 16 patients (100%) by 18 times of procedures at a median follow-up of 84 months[13]. The advantage of this procedure is no scarring in the perineum and little dyspareunia post-surgery. Oom et al.[7] documented healed RVFs in 16 (62%) of 26 patients by puborectalis sling interposition at a median follow-up of 14 months but healing rate was poorer in patients with previous repairs (31%) than that in patients without previous repair (92%).

Figure 1.

Transvaginal anterior levatorplasty.

a, Transverse incision in the posterior vaginal wall.

b, The puborectalis and pubococcygeal muscles are brought together by interrupted sutures to cover the fistula tract.

c, The posterior vaginal wall is closed without scar in the perineum.

3. Abdominal repair

Abdominal repairs are usually performed via a minimally invasive or open approach[2,10]. Abdominal repairs include fistula excision with multi-layered closure of the rectum and the vagina, accompanying with an interposition of well-vascularized omental tissue, resection of the part rectum, including the fistula followed by redo colorectal (or coloanal) anastomosis, and transanal colonic pull-through with delayed coloanal anastomosis after rectal resection[2,41,93-95]. Abdominal repair is indicated for non-amenable high RVF to transperineal repair, especially RVF after LAR[2,10,28,93-95]. Fistula excision with multi-layered closure of the rectum and the vagina can be performed only when the quality of tissues surrounding the fistula has minimal fibrosis, good blood supply, no infection, and no evidence of cancer recurrence. Rectal resection may be needed in cases with the possibility of multiple adhesions and difficult pelvic dissection[2]. ASCRS clinical practice guidelines suggest that RVFs resulting from colorectal anastomotic complications often require a transabdominal approach for repair and completion proctectomy with or without colonic pull-through or coloanal anastomosis may be required to treat radiation-related or recurrent complex RVF[11]. Success rate of fistula excision with multi-layered closure of the rectum and the vagina accompanying omental interposition is 90%-100% for RVFs with various causes[94,96]. Redo-coloanal anastomosis showed a success rate of 85.7% (6/7) in patients with RVFs after LAR[41]. Maggiori et al. reported a 79% success rate in patients with chronic anastomosis leakage after rectal resection (n = 24), including RVF formation (n = 9) undergoing transanal colonic pull-through with delayed coloanal anastomosis after rectal resection[95].

Conclusion

RVF is a challenging complication with unsatisfactory success and a significant burden for the patients. With insufficient clinical data due to the rare entity, we comprehensively reviewed the factors to determine management, classifications, principle of treatment, and conservative and surgical treatments with outcomes.

Conflicts of Interest

There are no conflicts of interest.

Author Contributions

All authors contributed to the study conception and design. Material preparation, data collection, and analysis were performed by Kotaro Maeda. The first draft of the manuscript was written by Kotaro Maeda and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.

Approval by Institutional Review Board (IRB)

Not applicable.