Seton Placement

The initial purpose of seton placement is to drain sepsis and define the fistula. However, its use as a definitive treatment is in doubt. The reported success rate of seton placement ranged from 0% to 100%, with a mean success rate of 45%. ^{, ,} One criticism of the procedure is the potential for damage to the sphincter, which may have been previously thinned out in many females.

Fistulectomy

The results of fistulectomy, which involves coring out of the fistula track with the repair of the internal opening at the pouch level, are discouraging. ^{, ,} Although these procedures are not commonly used, they may be appropriate in the treatment of a low fistula involving little or no sphincter muscle.

Fistula Plug

The introduction of collagen plugs as a treatment option for anal fistulas has led to the development of button plugs for the management of PVF. Although there are limited reports of success with conventional collagen plugs, the button plug has shown some promise. The technique involves securing the button portion on the pouch side of the fistula with dissolvable sutures. The button detaches within 4 weeks, leaving the collagen matrix in situ.

The early results of the button plug suggest a success rate of approximately 55% at week 16, but disappointingly, these results were not sustained over the long term. In a study of 11 patients with PVF, none had a successful healing outcome after 2 years. It is believed that early success may have been due to the persistence of the collagen plug within the fistula tract. However, the failure of local tissue in growth, along with the relatively short length of the PVF tract and the presence of a staple line, likely contribute to the long-term failure of the button plug approach. Given a lack of long-term response, the use of biological tissue plugs is currently not recommended as prime management of PVF.

Stem Cell Therapy

Therapy with stem cells, especially mesenchymal stem cells (MSCs), is a novel intervention for perianal fistulas and RVF in CD, whereas there are no reports on its efficacy for VF in UC after RPC and IPAA. Although MSC therapy holds great promise, it remains controversial in some cases. Recent literature demonstrates that MSCs likely possess the ability to (1) engraft following transplantation, (2) improve function through the bulking effect, (3) elicit trophic effects on the host, and (4) modulate inflammation. These properties may lead to beneficial histological, functional, and clinical outcomes. However, the exact mechanisms of MSCs in the treatment of VF are complex and not yet fully elucidated.

Transanal Advancement Flap

The transanal approach is simpler than abdominal reconstruction. It has been noted that the transanal flap was more effective than the trap door advancement flap in the management of PVF. However, patients should be carefully selected by identifying risk factors such as smoking, which can impair the success rate of this approach. Additionally, this approach has several disadvantages including suboptimal exposure and a risk of further sphincter injury in those with borderline continence. There are several key technical points to consider, including adequate drainage of any septal sepsis preoperatively, careful hemostasis, debridement or excision of any concurrent stricture, and tension-free re-anastomosis. One small study of 12 patients reported an 83% (N = 10) success rate with transanal repair (advancement flap, direct repair, and neo-ileoanal pouch advancement flap) in UC. In general, advancement flaps have been used as a surgical technique with a favorable success rate.

Transvaginal Repair

The transvaginal repair involves an inverted T-shaped incision in the lower vagina that incorporates the vaginal orifice of the PVF. Flaps are raised and the internal orifice of the fistula is identified and repaired with interrupted absorbable sutures. The levator muscles can then be brought across to cover the internal orifice repair, and the flaps of the vagina are then sutured back into position. Additionally, the repair can also be augmented by placing a collagen patch between the pouch and the vagina. Transvaginal repair may have advantages over the endoanal technique, as it allows a direct approach to the fistula, avoiding possible sphincter damage. However, the rich vascularity of the vaginal wall means hematoma can pose a significant postoperative risk. Good hemostasis during the procedure and postoperative use of a vaginal pack can reduce this risk. A systematic review including 143 transvaginal approaches reported a success rate of 51.0%.

Interposition Flap

The aim of using tissue flaps is to place healthy tissue between the two fistular openings. When a fistula arises from an ileoanal anastomosis lying within the anal canal or just above the sphincter, abdominal advancement of the anastomosis is not feasible due to insufficient length of the distal anal canal to clear the fistula. Fistulectomy and direct perineal repair appear to give poor results. ^, Gracilis muscle transposition (GMT) has been reported with one showing the use of the bulbocavernosus muscle flap for the repair of PVF. The gracilis muscle can be detached from its insertion and secured between the pouch and the vagina, providing a well-nourished, vascularized piece of tissue. ^, Two patients undergoing gracilis muscle repair reported no recurrence 3 months after stoma closure, and four treated by transposition of the rectus abdominis muscle were also symptom-free after a range of follow-ups of 6 to 30 months.

Transabdomino-Transanal-Perineal Approach

The transabdominal approach is recommended only for high PVF to avoid the risk of sphincter injury and for those with difficulty with transanal repair. In cases of high fistulas, long strictures, or gross sepsis and edema, it is recommended to proceed directly to laparotomy and to repair the fistulas. Pelvic fibrosis with poor pouch function after the abdominal salvage procedures has been observed by several experienced pouch centers. Furthermore, the transabdominal approach carries a risk of postoperative morbidities (40–56%), including the risk of short-gut syndrome. ^, This approach should not be undertaken lightly and only be done by an expert for better outcomes. A study from the Cleveland Clinic showed successful transabdominal repair of PVF in 10 out of 16 patients.

Pouch Excision

When a patient presents with extensive perineal or parapouch fistulas and sepsis, or when previous treatments have failed multiple times, pouch excision, with or without redo IPAA, may be warranted. However, a diverting ileostomy is advocated before the decision. Based on the literature, excision, and reconstruction of the pouch due to PVF, was used with a success rate of 65.4%. Some patients with PVF and the absence of direct evidence of CD may benefit from J-pouch-to-K-pouch conversion, using a preexisting pouch body or construction from a new loop of neo-distal ileum.

Seton Placement

The placement of a seton can be helpful in defining the fistula and draining associated sepsis. A small case reported a successful application in four patients. Unfortunately, this result has not been confirmed by other studies. ^, Arguments against its use include potential damage to any residual anal sphincter and the risk of further leakage and discharge. There is currently no evidence to support its routine use, except for the initial control of sepsis prior to definitive repair. Moreover, there is also a lack of studies examining the effect of using a seton before the definitive repair of PVF on improving patients’ outcomes.

Fistula Plug

The collagen fistula plug has been increasingly used with a high success rate in non-IBD patients. It consists of a cylindrical plug made of a cellular collagen matrix, which is inserted into the previously debrided fistula tract and secured in place by sutures on both sides of fistula openings. ^, The plug promotes an inflammatory response, which is gradually replaced by scar tissue. The design of the RVF plug has been modified from anorectal fistula plugs to incorporate additional components, such as a button on the rectal side, resulting in better outcomes. Its use in the CD-associated PVF or RVF remained to be defined.

Stem Cell Therapy

As a novel treatment, the safety and efficacy of MSCs in the management of perianal fistulas in CD patients have been established. The successful use of MSCs to RVF was also reported, with a remission rate being about 61%. However, all available evidence aims to evaluate the disease-associated fistula, and the data on the postoperative VF remain limited. Before its wide clinical application, the controversies requiring future studies on MSC treatment include the optimization of stem cell sources, development of a standardized protocol for cell harvest and culture safe for human use, determination of the optimal therapeutic dosages, and establishment of the best transplantation route and technique.

Transanal Advancement Flap

Transanal advancement flap involves mobilizing a cephalad-based flap of mucosa and submucosa from the rectum or pouch, excising the internal opening, and suturing the flap beyond the internal fistula opening. The advantage of the anal advancement flap is its fairly straightforward procedure and more distal mobility. ^, However, the disadvantages of this approach are the risk of damage to sphincters and the placement of the flap on the high-pressure side of VF. On top of that, transanal exposure can be suboptimal. It was reported that the success rate of this procedure for VF patients with CD is approximately 40% to 50%. ^{, ,}

Transvaginal Repair

The effectiveness of transvaginal repair of VF has been reported. ^, The advantage of this approach is that it is technically easier than the transanal approach with better exposure, good blood supply, avoidance of further sphincter injury, the possibility of repetition, and satisfactory results with less morbidity. However, a concern is that it is undertaken from the low-pressure side, with the higher pressure being on the rectum or pouch side, and there is a possibility of dyspareunia. To address this problem, direct closure of the rectum or pouch opening, the use of a suction drain in the intervening space, and an endovaginal pack may be utilized. Hematoma is a common complication because of the vascularity of the vagina, but the risk can be minimized with meticulous technique, drainage, and the use of a vaginal pack.

Interposition Flap

The use of muscle flaps in VF is well established. ^, However, these procedures are often performed after the failure of other repairs, particularly local repairs. It seems that interposition flaps have been underused in the repair of VF in large series, but they do have a role in the treatment of this difficult adverse postoperative sequela. Despite being clinically useful, interposition flap as first-line treatment for patients with VF is not currently recommended due to the availability of a small number of reported cases.

Transabdomino-Transanal-Perineal Approach

To perform a stapled anastomosis at or above the anorectal junction, it is recommended to choose an abdominoanal procedure, since there is enough distance to advance the anastomosis below the fistula. In this procedure, the rectum or pouch is dissected from the surrounding pelvic structures until the anastomosis is reached, which is then divided. The track is excised, and any defect in the vagina is repaired. Finally, a manual endoanal anastomosis is carried out to advance the rectum or pouch distally.