Anal function after ligation of the intersphincteric fistula tract

Is the ligation of the intersphincteric fistula tract (LIFT) procedure truly a sphincter preserving procedure for anal fistula? A scoping review of the literature

INTRODUCTION

The ligation of the intersphincteric fistula tract (LIFT) procedure has garnered popularity with its success rates and purported sphincter-continence preservation. However, there remains a paucity in the literature on the objective evaluation of sphincter integrity and fecal continence after the LIFT procedure.

OBJECTIVES

The present study undertakes a scoping review to systematically explore and map the published literature, to evaluate the sufficiency of data on the impact on continence in patients after the LIFT procedure.

DESIGN

A systematic search of MEDLINE, PubMed, EMBASe, CINAHL was performed from January 2007 to April 2020 and 597 publications were identified. Forty-two satisfied the inclusion and exclusion criteria. We performed a scoping review in accordance to the PRISMA-ScR guidelines.

RESULTS

Only 3 (7.1%) of publications were randomized controlled trials, of which just 1 (2.4%) measured incontinence as a primary outcome. Continence was measured both pre- and post-LIFT in 30 (71.4%), of which 19 (45.2%) had a fixed protocol for continence assessment, which was heterogeneous between the studies. Continence was assessed using subjective scoring systems in 27 (64.3%) and objective measurement was performed in just 6 (14.3%). No studies performed post-operative anatomical assessment of the anal sphincter complex.

CONCLUSIONS

Long-term continence in post-LIFT patients is not supported with adequately powered prospective longitudinal trials using rigorously protocoled pre- and post-operative assessment of continence. Future research that focuses on a combination of objective assessment using anal manometry as well as anatomical assessment of the sphincter complex on top of subjective evaluation is needed before we can be certain if LIFT is indeed a sphincter and continence preserving technique.

Mucosal advancement flap versus ligation of the inter-sphincteric fistula tract for management of trans-sphincteric perianal fistulas in the elderly: a retrospective study

PURPOSE

There is no consensus on the standard approach for trans-sphincteric perianal fistulas (TPAF) in the elderly population. The most commonly used sphincter-saving procedures are ligation of the inter-sphincteric fistula tract (LIFT) and mucosal advancement flap (MAF). We aimed to evaluate the incidence and risk factors for recurrence and incontinence in elderly patients with TPAF using both approaches.

METHODS

This retrospective study included 257 patients who underwent LIFT (136 patients) or MAF (121 patients) for de novo and cryptoglandular TPAF between July 2018 and July 2021. Recurrent fistulas were clinically and radiologically detected using MRI. Postoperative incontinence was evaluated using the Wexner score and anorectal manometry. Logistic regression analysis was used to detect the risks of recurrence and incontinence.

RESULTS

The median ages of the patients were 68 (64, 74) and 68 (65, 74) years in the LIFT and MAF groups, respectively. Higher recurrence rates were observed after LIFT (17 (12.5%)) than after MAF (13 (10.7%)), but the difference was not statistically significant (P = 0.662). Postoperative incontinence was observed in 18 patients (13.2%) and seven patients (5.8%) in the LIFT and MAF groups, respectively (P = 0.044). The predictors for fistula recurrence were smoking (OR, 75.52; 95% CI, 1.02 to 5611.35; P = 0.049), length of tract (OR, 17.3; 95% CI, 1.49 to 201.13; P = 0.023), and CD classification (OR, 7.08; 95% CI, 1.51 to 33.14; P = 0.013). A low Charlson comorbidity index score (≤ 5) (OR, 0.68; 95% CI, 0.47 to 0.99; P = 0.046) and high postoperative mean squeeze anal pressure (OR, 0.97; 95% CI, 0.95 to 0.99; P = 0.001) were significant factors associated with reduced risk of incontinence. In particular, LIFT was associated with a significantly higher risk of incontinence than MAF (OR, 2.089; 95% CI, 1.006 to 4.33; P = 0.04).

CONCLUSIONS

The healing rates of MAF and LIFT procedures did not differ significantly; however, continence was significantly better after MAF. MAF should be added to the guidelines as a good option for the treatment of TPAF in elderly patients.

TRIAL REGISTRATION

The study was registered as a clinical trial www.

CLINICALTRIALS

gov (NCT06616662).

Subtotal fistulectomy and sliding anoderm flap: A new sphincter-sparing technique for anal fistula

AIM

The underlying causes of failure or recurrence after ligation of the intersphincteric fistula tract are postulated to be refistulization, breakdown of the closure wound in the intersphincteric plane and faecal contents entering the internal opening, thereby causing recurrent infection. The aim of this study is to demonstrate the outcomes of subtotal fistulectomy with sliding anoderm flaps to prevent refistulization.

METHOD

This retrospective study used prospectively collected data. Patients with transsphincteric or intersphincteric fistulas were enrolled between August 2021 and July 2023. An anal manometric study was performed before and after surgery. Faecal incontinence was evaluated using the faecal incontinence severity index (FISI). Failure was defined as nonhealing of the surgical wound or fistula.

RESULTS

Fifty-one patients who underwent subtotal fistulectomy with a sliding anoderm flap were included. After a median follow-up of 12 months (range 4-27 months), primary healing was achieved in 49 patients (96%). Two patients experienced treatment failure, while none developed postoperative recurrence. The median healing time was 10 weeks (range 6-24 weeks). The FISI scores did not change significantly after the surgery. The median resting pressure significantly reduced after surgery [125 cmH2O (range 59-204 cmH2O) vs. 99 cmH2O (range 36-176 cmH2O); p = 0.0001]. The median squeeze pressure significantly decreased after surgery [356 cmH2O (range 137-579 cmH2O) vs. 329 cmH2O (range 72-594 cmH2O; p = 0.005)].

CONCLUSION

Subtotal fistulectomy with a sliding anoderm flap showed excellent healing rates with no postoperative deterioration of anal function.

High failure rates following ligation of the intersphincteric fistula tract for transsphincteric anal fistulas: are preoperative MRI measurements of the fistula tract predictive of outcome?

AIM

Treatment of transsphincteric fistulas (TSFs) with fistulotomy after an indwelling seton is tempered by risks of incontinence and litigation. Thus, ligation of the TSF tract has been popularized as an alternative option. We previously reported on 107 patients who underwent ligation of the intersphincteric fistula tract (LIFT), with a 46% failure rate. Posterior fistula was the only predictor of recurrence. The aim of the present work was to investigate whether the length, width or depth of the fistula measured on preoperative MRI was correlated with recurrence.

METHOD

Following institutional review board approval, a retrospective analysis of our prospective Complex Anal Fistula Database from 1 January 2011 to 31 August 2019 was performed. Patients with TSF who underwent preoperative MRI and LIFT were included. Fistula location was classified as anterior, posterior or lateral. MRI measurements of fistula length, width and depth (in the intersphincteric groove) were performed. The type and rate of postoperative recurrence were analysed.

RESULTS

173 patients underwent MRI for an anal fistula; of these 40 underwent LIFT and 22/40 (55%) had preoperative MRI. There was no difference in the length, width or depth of anterior (n = 9), posterior (n = 7) or lateral (n = 6) fistula tracts. The overall recurrence rate was 9/22 (41%). Posterior TSFs had the highest recurrence rate (5/7, 71%).

CONCLUSION

The mean length, width, and depth of the fistula tract, measured at the preoperative site of LIFT in the intersphincteric groove, did not correlate with recurrence regardless of fistula location.

Ligation of the intersphincteric fistula tract procedure and its modifications

Purpose Treatment of anal fistulae is regarded as a challenge due to the diverse nature of this disease and its countless complications. Ligation of the intersphincteric fistula tract procedure and its modifications have been popularized among many surgeons worldwide due to their simplicity and promising outcomes. The main purpose of this article was to conduct a comprehensives review of the published literature on ligation of the intersphincteric fistula tract procedure and its modifications.

Method PubMed, the Cochrane database and Ovid were searched from January 2007 to June 2017. Fully published peer-reviewed studies which applied ligation of the intersphincteric fistula tract procedure and its modifications for the treatment of anal fistulae of cryptogenic origin with follow-up of median 12 months were eligible. Uncompleted studies, case reports, reviews, abstracts, letters, short communication, comments, and studies which did not fulfill inclusion criteria were excluded. The primary outcome was to measure primary healing, overall healing, failure, and recurrence of ligation of the intersphincteric fistula tract procedure and its modifications.

Results Twenty-two studies were identified with only ten studies meeting criteria of inclusion. Original ligation of the intersphincteric fistula tract was performed in five studies with a population of 199 patients while the remaining five studies showed four different modifications of the ligation of the intersphincteric fistula tract with a total number of 147 patients. Both original LIFT and its modifications have promising as well as potentially similar outcomes; primary healing in the original ligation of the intersphincteric fistula tract (73.95%) (95% CI 60.3–85.6) performed less than the modifications (82.3%) (95% CI 64.8–94.7). Overall healing in the original ligation of the intersphincteric fistula tract (78.9%) (95% CI 58.5–93.7) performed relatively less than in the modifications (93.6%) (95% CI 81.4–99.6). Failure in the original ligation of the intersphincteric fistula tract (17.9%) (95% CI 4.9–36.5) performed almost the same as the modifications (17.7%) (95% CI 5.3–35.2). Recurrence in the original ligation of the intersphincteric fistula tract was 9.7% (95% CI 1.7–23.2). However, there was no recurrence in the modifications.

Conclusion Ligation of the intersphincteric fistula tract and its modifications are effective and simple procedures in treating simple anal fistulae, especially high transsphincteric ones. However, more trials should be performed to evaluate its effectiveness regarding complex fistulae.

Tools for fecal incontinence assessment: lessons for inflammatory bowel disease trials based on a systematic review

BACKGROUND

Fecal incontinence is a disabling condition affecting up to 20% of women.

OBJECTIVE

We investigated fecal incontinence assessment in both inflammatory bowel disease and non-inflammatory bowel disease patients to propose a diagnostic approach for inflammatory bowel disease trials.

METHODS

We searched on Pubmed, Embase and Cochrane Library for all studies on adult inflammatory bowel disease and non-inflammatory bowel disease patients reporting data on fecal incontinence assessment from January 2009 to December 2019.

RESULTS

In total, 328 studies were included; 306 studies enrolled non-inflammatory bowel disease patients and 22 studies enrolled inflammatory bowel disease patients. In non-inflammatory bowel disease trials the most used tools were the Wexner score, fecal incontinence quality of life questionnaire, Vaizey score and fecal incontinence severity index (in 187, 91, 62 and 33 studies). Anal manometry was adopted in 41.2% and endoanal ultrasonography in 34.0% of the studies. In 142 studies (46.4%) fecal incontinence evaluation was performed with a single instrument, while in 64 (20.9%) and 100 (32.7%) studies two or more instruments were used. In inflammatory bowel disease studies the Wexner score, Vaizey score and inflammatory bowel disease quality of life questionnaire were the most commonly adopted tools (in five (22.7%), five (22.7%) and four (18.2%) studies). Anal manometry and endoanal ultrasonography were performed in 45.4% and 18.2% of the studies.

CONCLUSION

Based on prior validation and experience, we propose to use the Wexner score as the first step for fecal incontinence assessment in inflammatory bowel disease trials. Anal manometry and/or endoanal ultrasonography should be taken into account in the case of positive questionnaires.

LIFT and BioLIFT: a 10-Year Single-Centre Experience of Treating Complex Fistula-In-Ano With Ligation of Intersphincteric Fistula Tract Procedure With or Without Bio-prosthetic Reinforcement (BioLIFT)

PURPOSE

To assess the outcome of ligation of intersphincteric fistula tract (LIFT) and bioprosthetic graft (BioLIFT) in the management of transsphincteric perianal fistula.

METHODS

A single-institution retrospective analysis of all patients undergoing LIFT and BioLIFT from January 2009 to June 2018 was performed. Only patients who had LIFTs and BioLIFT performed as their primary sphincter-preserving procedure was included. Primary outcome measured was primary healing. Secondary outcomes measured were secondary healing, morbidity, time to recurrence, and pre- and post-operative anorectal manometry. Chi-square analysis was used to determine predictive factors.

RESULTS

A total of 116 patients were identified. One hundred five had LIFT and 11 had BioLIFT. The total primary healing rate was 60.3% (62.9% and 34.9% for LIFT and BioLIFT respectively). The overall secondary healing rate was 80.2% (80.0% and 81.9% for LIFT and BioLIFT respectively). There was no inpatient morbidity or post-procedural faecal incontinence reported. There was no significant change in the pre- and post-operative manometries in either group (P = 0.417 and P = 0.834 for LIFT and BioLIFT respectively). The only predictor for primary failure identified was anteriorly located fistula.

CONCLUSION

LIFT and BioLIFT compare favourably with other sphincter-preserving procedures. LIFT and BioLIFT can be performed safely, with minimal morbidity and with no reported loss of sphincteric function.

Ligation of intersphincteric fistula tract (LIFT) in treatment of anal fistula: An updated systematic review, meta-analysis, and meta-regression of the predictors of failure

BACKGROUND

Ligation of intersphincteric fistula tract has gained increasing popularity as a sphincter-sparing technique for complex anal fistula. The present review aimed to investigate the pooled success and complication rates of ligation of intersphincteric fistula tract in the published literature and to explore the risk factors for failure after ligation of intersphincteric fistula tract.

METHODS

A Preferred Reporting Items for Systematic Reviews and Meta-Analyses-compliant literature search was conducted. Electronic databases were searched in the period of January 2007 through April 2019 for studies that assessed the outcome of the ligation of intersphincteric fistula tract procedure. The main outcomes of the review were the pooled success and complication rates of ligation of intersphincteric fistula tract, predictors of failure after ligation of intersphincteric fistula tract, operation time, hospital stay, and how failures were managed.

RESULTS

Twenty-six studies comprising 1,378 patients (996 male) were included in this review. The mean age of patients was 42.3 ± 4.2 years. The weighted mean rate of success was 76.5%. The median follow-up duration was 16.5 months. The weighted mean complication rate was 13.9%. The most common complication was wound dehiscence. Fecal incontinence was recorded in 1.4% of patients. Factors that were statistically significantly associated with failure after the ligation of intersphincteric fistula tract procedure were horseshoe fistulas, fistulas associated with Crohn's disease, and those with a history of previous fistula surgery.

CONCLUSION

The pooled success and complication rates of the ligation of intersphincteric fistula tract procedure were about 76% and 14%, respectively. Horseshoe fistulas, Crohn's disease, and previous fistula surgery were identified as predictors for failure after ligation of intersphincteric fistula tract procedure.

Long-term outcomes and quality of life following ligation of the intersphincteric fistula tract for high transsphincteric fistulas

AIM

Published outcomes following ligation of the intersphincteric fistula tract (LIFT) for high transsphincteric fistulas (HTFs) are equivocal probably because most trials are small and comprise mixed patient populations. The aim of this study was to highlight the long-term efficacy of LIFT for HTFs in a large homogeneous sample and to determine the risk factors that contribute to non-healing resulting in failure and recurrence.

METHOD

A retrospective study was performed which assessed patients with HTFs treated by LIFT without prior loose setons from September 2012 to December 2017. Continence function was evaluated by the Wexner incontinence scale and anal manometry. Quality of life was assessed by using the faecal incontinence quality of life (FIQL) scale with four domains: lifestyle, coping, depression and embarrassment.

RESULTS

Seventy patients with HTFs underwent 71 LIFT procedures. The primary healing rate was 81.7% with a median follow-up duration of 16.5 (range 4.5-68) months. The healing rates of mature and immature fistulas were 83.7% and 77.3%, respectively. Two patients suffered failure with an unhealed intersphincteric wound. Recurrence occurred in 11 patients. Incontinence of flatus, present in four patients before surgery, improved postoperatively. Two patients undergoing LIFT combined with fistulotomy complained of flatus incontinence after surgery. No significant differences between preoperative and postoperative Wexner score, maximum resting pressure and maximum squeeze pressure were detected. The FIQL was improved in lifestyle, coping and depression. No risk factor for non-healing was found.

CONCLUSION

LIFT has a promising long-term outcome for HTFs, with negligible impairment on continence and improved quality of life.

CAN THREE-DIMENSIONAL ANORECTAL ULTRASONOGRAPHY BE INCLUDED AS A DIAGNOSTIC TOOL FOR THE ASSESSMENT OF ANAL FISTULA BEFORE AND AFTER SURGICAL TREATMENT?

BACKGROUND

There is no a clear knowledge concerning the division of any part of the anal sphincter complex and the effect of this procedure on the function of the anal canal during the treatment of perianal fistula.

OBJECTIVE

To evaluate the usefulness of 3D anorectal ultrasound in the assessment of anal fistula, quantifying the length of the sphincter muscle to be transected, selecting patients for different approaches and identifying healing, failure or recurrence after the surgical treatment.

METHODS

A prospective study included patients with primarily cryptogenic transsphincteric anal fistula assessed by fecal Incontinence score, tri-dimensional anorectal ultrasound and anal manometry before and after surgery. Based on 3D-AUS, patients with ≥50% external sphincter or external sphincter+puborectalis muscle involvement in males and ≥40% external sphincter or external sphincter+puborectalis muscle in females were referred for the ligation of the intersphincteric tract (LIFT) or seton placement and subsequent fistulotomy; and with <50% involvement in males and <40% in females were referred to one-stage fistulotomy. After surgery, the fibrosis (muscles divided) and residual muscles were measured and compared with the pre-operative.

RESULTS

A total of 73 patients was included. The indication for the LIFT was significantly higher in females (47%), one-stage fistulotomy was significantly higher in the males (46%) and similar in seton placement. The minor postoperative incontinence was identified in 31% of patients underwent sphincter divided and were similar in both genders. The 3D-AUS identified seven failed cases.

CONCLUSION

The 3D ultrasound was shown to be an effective method in the preoperative assessment of anal fistulas by quantifying the length of muscle to be divided, as the results were similar at the post-operative, providing a safe treatment approach according to the gender and percentage of muscle involvement. Additionally, 3D ultrasound successfully identified the healing tissue and the type of failure or recurrence.

Draining Setons as Definitive Management of Fistula-in-Ano

BACKGROUND

The ideal management for fistula-in-ano would resolve the disease while preserving anal continence.

OBJECTIVE

The purpose of this study was to determine the efficacy of draining seton alone in achieving resolution or significant amelioration of symptoms for patients with fistula-in-ano.

DESIGN

This was a retrospective case series involving chart review and telephone interviews. A single colorectal surgeon performed surgeries between June 1, 2005, and June 30, 2014.

SETTINGS

The study was conducted by a single surgeon in a large urban city.

PATIENTS

Patient ≥18 years of age presenting with fistula-in-ano of cryptoglandular origin were included.

MAIN OUTCOME MEASURES

Resolution of symptoms or significant symptom improvement requiring no additional surgical management and rate of recurrence were measured.

RESULTS

A total of 76 patients (53 men) met the inclusion criteria. Mean age was 45 years (range, 19-73 y). The average time to seton removal was 36.6 weeks (range, 6.0-188.0 wk). Mean follow-up was 63 months (range, 7-121 mo). Fifty-seven patients (75%) were reached for telephone interview. Fifty-six patients (73.7%) had complete symptom resolution, and 14 (18.4%) had significant amelioration of symptoms with no additional surgical management required. Six (7.9%) had persistent severe symptoms. Five (7.1%) had a recurrence after seton removal. Rates of symptom resolution and recurrence were similar between patients whose setons were removed before or after 26 weeks (median time of seton removal) from the time of placement. Twenty-one patients (27.6%) required 1 or more additional operative procedures before planned seton removal to unroof a collection and/or replace the seton, and this represented the most significant risk factor for failure of resolution or improvement or recurrence (relative risk = 7.0).

LIMITATIONS

This study was retrospective and represents a single surgeon experience.

CONCLUSIONS

Placement of draining seton alone is a viable treatment option for definitive symptomatic management of fistula-in-ano. Because draining setons are sphincter and function preserving, their use should be considered as primary management for fistula-in-ano. See Video Abstract at http://links.lww.com/DCR/A552.

Definitive seton management for transsphincteric fistula-in-ano: harm or charm?

AIM

The treatment of transsphincteric anal fistula requires a balance between eradication of the disease and preservation of faecal control. A cutting seton is an old tool that is now out of vogue for many surgeons. We hypothesized that the concept remains reliable and safe with results that exceed those reported for many of the more recently described methods.

METHOD

A retrospective review was conducted of real-time electronic health records (single institution, single surgeon) of patients presenting during the 14 years between 2001 and 2014 with a transsphincteric anal fistula who were treated with a cutting seton. Excluded were patients with Crohn's disease, fistulae related to malignancy or a previous anastomosis and patients whose fistula was treated by another method including a loose draining seton. Data collection included demographics, duration of the disease, duration of the treatment, outcome and continence.

RESULTS

In all, 121 patients (80 men) of mean age 40.2 ± 12.2 years (range 18-76) with a mean follow-up of 5.1 ± 3.3 (1-24) months were included in the analysis. The median duration of symptoms was 6 (1-84) months; 36% had failed other fistula surgery, 12% had a complex fistula with more than one track and 35% had some form of comorbidity. The median time to healing was 3 (1-18) months; 7.4% required further surgery, but eventually 98% had complete fistula healing. The incontinence rate decreased postoperatively to 11.6% from 19% before treatment with 17/121 with pre-existing incontinence resolved and 8/107 new cases developing.

CONCLUSION

Despite its retrospective non-comparative design, the study has demonstrated that a cutting seton is a safe, well tolerated and highly successful treatment for transsphincteric anal fistula and is followed overall by improved continence. The results compare very favourably with other techniques.

Management of Complex Anal Fistulas

Complex anal fistulas require careful evaluation. Prior to any attempts at definitive repair, the anatomy must be well defined and the sepsis resolved. Several muscle-sparing approaches to anal fistula are appropriate, and are often catered to the patient based on their presentation and previous repairs. Emerging technologies show promise for fistula repair, but lack long-term data.

Ligation of Intersphincteric Fistula Tract: a Sphincter-Sparing Option for Complex Fistula-in-Ano

Fistulae-in-ano represent one of the more challenging anorectal diseases faced by surgeons, as appropriate management requires careful balance between the need for local sepsis control and patients' desire to maintain fecal continence. The ligation of intersphincteric fistula tract (LIFT) procedure, first described by Rojanasakul and colleagues in 2007, represents a sphincter-sparing technique for fistula management which has become our method of choice for transsphincteric fistulas. With this technique, patients frequently enjoy successful fistula healing., or, at worst, conversion to a less complex fistula tract. Here, we describe and illustrate our surgical approach and review success and recurrence rates presented in the published literature.

New developments in colorectal surgery

PURPOSE OF REVIEW

Surgical management of diseases of the colon and rectum continues to evolve. This review examines the recent publications that have led to or may lead to changes in practice in this field.

RECENT FINDINGS

We identified and reviewed the recent publications in the areas of colon, rectal, and anal cancers; inflammatory bowel disease; incontinence; diverticulitis; hemorrhoids; fistulas; and quality improvement initiatives.

SUMMARY

New technologies and novel questions have changed practice and will improve patient outcomes. Multiinstitutional studies, ideally randomized, continue to be essential to answer the questions that will lead to identification of best practices.

Management of complex anorectal fistulas with seton drainage plus partial fistulotomy and subsequent ligation of intersphincteric fistula tract (LIFT)

BACKGROUND

Ligation of intersphincteric fistula tract (LIFT) is a relatively new technique in the treatment of complex anorectal fistulas. As it spares the anal sphincter, rates of post-operative incontinence may be lower when compared to conventional treatment. To date, there have not been enough reports of long-term fistula recurrence rates. We performed a long-term follow-up study of 75 patients who underwent LIFT following seton drainage and partial fistulotomy.

METHODS

Only patients with complex cryptogenic anorectal fistulas were included. After seton insertion and partial fistulotomy, the tract was reviewed at 4 months for the absence of anorectal sepsis. Patients then underwent LIFT in a day surgery setting. Operative time, complications, recurrences and incontinence were evaluated.

RESULTS

Between May 2008 and June 2013, 75 patients [51 men, mean age 49.5 years, standard error of the mean (SEM) 1.4 years] were treated with a LIFT protocol. The mean operating time for LIFT was 13.2 min (SEM 1.5 min). Complications included minor bleeding, superficial wound dehiscence and perianal pain. At a mean follow-up of 14.6 months (SEM 1.7 months), there were nine (12 %) recurrences, diagnosed at a mean 9.2 months (SEM 2.7 months). They were treated with seton insertion followed by LIFT with biomesh or anorectal advancement flap, and there were no subsequent recurrences. Review of preoperative and post-operative continence scores revealed only one (1.3 %) patient with minor incontinence following LIFT. Recurrences were significantly related to fistulas with multiple tracts (p < 0.001).

CONCLUSIONS

Our results suggest that the protocol of seton insertion and partial fistulotomy followed by LIFT is associated with a low recurrence rate comparing well with published results from studies involving other techniques and protocols for treating anal fistula.