Identification of epithelialization in high transsphincteric fistulas

The impact of adipose fat tissue on the pathogenesis of crypto-glandular anal fistula

<b>Indroduction:</b> Cryptoglandular perianal fistula represents a prevalent benign anorectal condition, primarily addressed through surgical interventions, occasionally posing considerable therapeutic challenges. The associated decline in patient quality of life underscores the significance of effective management. However, the lack of a fully understood pathogenesis complicates the treatment approach. Recent research has proposed the involvement of adipose fat tissue in the inflammatory response and pathogenesis of cryptoglandular anal fistula.<b>Aim:</b> The study aims to characterize the role of adipose fat tissue in the pathogenesis of cryptoglandular anal fistula, with a specific focus on understanding the potential involvement of proinflammatory cytokines in the development of chronic inflammation.<b>Materials and methods:</b> This study involved the characterization of serum levels of inflammatory cytokines and adipose tissue hormones. A total of 35 samples from both simple and complex cryptoglandular perianal fistula cases were collected during surgical procedures.<b>Results:</b> Serum levels of leptin, resistin, IL-1β, and IL-8 were significantly elevated in patients operated on due to complex cryptoglandular perianal fistula when compared to patients with simple fistula. Adiponectin was significantly lowered in samples from complex perianal fistula in comparison to simple fistula.<b>Conclusions:</b> Complex perianal cryptoglandular fistula has a reduced level of anti-inflammatory adipokines i.e. adiponectin, and an increased level of proinflammatory resistin, leptin, IL-1β, and IL-8.

Role of Adipose Tissue Hormones in Pathogenesis of Cryptoglandular Anal Fistula

The cryptoglandular perianal fistula is a common benign anorectal disorder that is managed mainly with surgery and in some cases may be an extremely challenging condition. Perianal fistulas are often characterized by significantly decreased patient quality of life. Lack of fully recognized pathogenesis of this disease makes it difficult to treat it properly. Recently, adipose tissue hormones have been proposed to play a role in the genesis of cryptoglandular anal fistulas. The expression of adipose tissue hormones and epithelial-to-mesenchymal transition (EMT) factors were characterized based on 30 samples from simple fistulas and 30 samples from complex cryptoglandular perianal fistulas harvested during surgery. Tissue levels of leptin, resistin, MMP2, and MMP9 were significantly elevated in patients who underwent operations due to complex cryptoglandular perianal fistulas compared to patients with simple fistulas. Adiponectin and E-cadherin were significantly lowered in samples from complex perianal fistulas in comparison to simple fistulas. A negative correlation between leptin and E-cadherin levels was observed. Resistin and MMP2 levels, as well as adiponectin and E-cadherin levels, were positively correlated. Complex perianal cryptoglandular fistulas have a reduced level of the anti-inflammatory adipokine adiponectin and have an increase in the levels of proinflammatory resistin and leptin. Abnormal secretion of these adipokines may affect the integrity of the EMT in the fistula tract. E-cadherin, MMP2, and MMP9 expression levels were shifted in patients with more advanced and complex perianal fistulas. Our results supporting the idea of using mesenchymal stem cells in the treatment of cryptoglandular perianal fistulas seem reasonable, but further studies are warranted.

Perioperative Factors Affecting the Healing of Rectovaginal Fistula

Rectovaginal fistula is rare, but a severe complication in gynecology, which despite the effort of clinicians is still not treated successfully in many cases. According to statistics, the healing rates of surgery in patients with RVF range from 20 to 100%. The treatment effectiveness depends on the etiology of fistula, the age of the patients, the presence of comorbidities, the type of surgery and many other factors. Considering the low efficiency of treatment and the high risk of recurrence, the question of possible methods to improve the results occurs. In our review, we analyzed both modifiable and non-modifiable factors which may influence the treatment, healing rate and future fate of the patients. Taking into account all analyzed risk factors, including age, comorbidities, smoking status, microbiology, medications, stoma and stool features, we are aware that rectovaginal fistula's treatment must be individualized and holistic. In cases of poorly healing RVF, the drainage of feces, the use of antibiotic prophylaxis or the implementation of estrogen therapy may be useful. Moreover, microbiome research in women with RVF and towards estrogen therapy should be performed in order to create treatment algorithms in women with fistulae. Those interventions, in our opinion, may significantly improve the outcome of the patients.

The potential roles of gut microbiome in anal fistula

Anal fistula is a common proctological disease, but the thorough mechanisms of the anal fistula formation are still unclear. An increasing number of studies have revealed the crucial role of gut microbiota in intestinal diseases. We used 16S rRNA gene sequencing to analyze the intestinal microbiome in order to determine whether there are differences in the microbiome between anal fistula patients and healthy individuals. The microbiome samples were extracted by repeatedly wiping the rectal wall with intestinal swab. Before this operation, the whole intestine of all participants was irrigated and the score of the Boston bowel preparation scale reached 9. The biodiversity of gut microbiome of rectum revealed significant difference between anal fistula patients and healthy individuals. 36 discriminative taxa were identified by LEfSe analysis between two groups. At the phylum level, Synergistetes was enriched in anal fistula patients, while Proteobacteria was higher in healthy individuals. We also found that at the genus level, Blautia, Faecalibacterium, Ruminococcus, Coprococcus, Bacteroides, Clostridium, Megamonas and Anaerotruncus were highly enriched in anal fistula patients, while the microbiome of healthy individuals was enriched with Peptoniphilus and Corynebacterium. Spearman correlations showed the extensive and close association among genera and species. Finally, a diagnostic prediction model was constructed by random forest classifier, and the area under curve (AUC) reached 0.990. This study gave an important hint for analyzing gut microbiome of rectum in anal fistula patient.Keypoints.We use the 16S rRNA gene sequencing to test the microbiome samples extracted from the intestinal swab. This is the first study to explore the gut microbiome of rectum using this workflow. We also found the distinct gut microbiome of rectum differences between anal fistula patients and healthy individuals.

Crohn's Disease-Associated and Cryptoglandular Fistulas: Differences and Similarities

Perianal fistulas are defined as pathological connections between the anorectal canal and the perianal skin. Most perianal fistulas are cryptoglandular fistulas, which are thought to originate from infected anal glands. The remainder of the fistulas mainly arises as complications of Crohn's disease (CD), trauma, or as a result of malignancies. Fistulas in CD are considered as a consequence of a chronic and transmural inflammatory process in the distal bowel and can, in some cases, even precede the diagnosis of CD. Although both cryptoglandular and CD-associated fistulas might look similar macroscopically, they differ considerably in their complexity, treatment options, and healing rate. Therefore, it is of crucial importance to differentiate between these two types of fistulas. In this review, the differences between CD-associated and cryptoglandular perianal fistulas in epidemiology, pathogenesis, and clinical management are discussed. Finally, a flow chart is provided for physicians to guide them when dealing with patients displaying their first episode of perianal fistulas.

The pathogenesis of cryptoglandular anal fistula: New insight into the immunological profile

AIM

The aetiology of cryptoglandular anal fistula (AF) is poorly understood. Evidence suggests that persistence and/or recurrence of the disease is more related to inflammatory than infectious factors. The aim of this study was to investigate the immune profile of cryptoglandular AF and to perform a histopathological characterization.

METHOD

Fistulectomy was performed in all patients; healthy ischioanal fat from the same patients was used as a control. Samples were evaluated by the Luminex xMAP system for the detection of 27 analytes. AF tissues were analysed using immunofluorescence. Staining was performed using primary antibodies to identify M1 inflammatory and M2 anti-inflammatory macrophages. Selective staining of total T lymphocytes and different T lymphocyte subsets was performed.

RESULTS

Twenty patients with AF underwent a fistulectomy. Specific cytokine pathways differentiated AF from healthy tissue: pro-inflammatory cytokines interleukin (IL)-1β, IL-4, IL-8 and IL-17 and the anti-inflammatory cytokine IL-10 were overexpressed in AF compared with controls. Chemokines involved in macrophage recruitment (CCL2, CCL3, CCL4) were higher in AF than in healthy fatty tissue. Moreover, we showed that Tc17 cells characterize AF patients, thus confirming the enzyme-linked immunosorbent assay data. Furthermore, elevated infiltration of CD68+ myeloid cells and a reduction of the M1/M2 ratio characterize AF patients.

CONCLUSION

A combination of inflammatory cytokines, chemokines and growth factors reside in the wound microenvironment of AF patients. For the first time an important prevalence of Tc17 cells and a reduction in the M1/M2 ratio was observed, thus suggesting new insights into the immunological characterization of AF patients.

Anti TNF treatment of complex perianal fistulas in children without luminal Crohn's disease: Is it an option?

OBJECTIVES

Complex perianal fistulas (CPFs) in children even in the absence of luminal symptoms prompt evaluation for Crohn's disease (CD). Reports of isolated CPF in children, however, are sparse. In perianal CD, antitumor necrosis factor α (anti TNF) therapy is recommended. We aimed to describe our experience with anti TNF therapy in children with isolated CPF without evidence of luminal CD.

METHODS

We retrospectively reviewed charts of patients with isolated CPF who were treated with anti TNF agents between 2011 and 2019 in a tertiary center. MRI pelvis findings at baseline versus end of follow up were scored using MAGNIFI-CD. Outcomes included clinical remission, radiological response and radiological remission based on MAGNIFI-CD score at end of follow up.

RESULTS

Overall, 17 patients were identified, [10 males (59%), mean age at anti TNF initiation 13.4 ± 2.9 years]. Median time from perianal disease onset to anti TNF was 16.5 months (IQR 9.4-36.4). None of the patients had luminal inflammation. Prior to anti TNF, all patients had been treated with antibiotics without sufficient improvement, and 9/17 with abscess drainage and or Seton insertion. Nine patients (53%) were treated with infliximab while 8 (47%) received adalimumab. Median duration of follow up was 30.7 months (IQR = 12.7-44.8). At the end of follow up 9 patients (53%) achieved clinical remission. When comparing MRI prior to and after anti TNF, 36% (5/14) had radiologic response, of whom 2 (14%) achieved radiologic resolution.

CONCLUSION

Anti TNF agents may be an effective treatment option for children with isolated CPF. Whether these patients should be considered part of the CD phenotypic spectrum or a distinct entity is unclear.

LEVELS OF EVIDENCE

Therapeutic.

Human Amniotic Membrane for the Treatment of Cryptoglandular Anal Fistulas

Background: Implantation of the amniotic membrane and their derivatives can have a beneficial effect on tissue repair and regeneration. We report for the first time the implant of an amniotic membrane in a patient affected by cryptoglandular anal fistula. Methods: A patch of human amniotic membrane was implanted in a female patient affected by an anterior transphincteric fistula. Following an accurate curettage of the anal fistula, the cryopreserved amniotic membrane was thawed and then washed in the operating room; one side of the membrane was transfixed with a resorbable suture thus creating an implantable fusiform patch. The membrane was subsequently implanted into the fistula tract from the external to the internal opening. The inner and outer parts of the membrane were then sutured to the internal and external fistula openings. Results: No intraoperative or postoperative complications occurred. The patient was discharged one day after the procedure after an uneventful hospitalization. At the 1-week, 1- and 3-month follow-up visits no pain (VAS 0) was referred by the patient and no inflammation was evident at the level of the previous external fistula opening. Conclusions: The implant of human amniotic membrane in a patient affected by cryptoglandular anal fistula was safely and easily performed. Moreover, future studies to assess the efficacy in the long-term follow-up are needed.

LIFT: a feasible option for primary and recurrent fistulas

BACKGROUND

The development of a surgical solution for anal fistulas with minimal recurrence and morbidity remains a challenge. Ligation of the intersphincteric fistula tract (LIFT), however, is a sphincter sparing technique that provides complete resolution of the transsphincteric fistula as well as minimizing recurrence and fecal incontinence. Our goal is to evaluate the efficacy of fistula tract ligation for primary and recurrent fistulas.

METHODS

A retrospective single-center case study was conducted from data between 2015 and 2019 in a large district hospital in Antwerp, Belgium. Patients who underwent LIFT were included. Demographic patient data as well as primary outcome during the follow-up period were collected. A systematic literature review and analysis was conducted with terms [ANAL FISTULA] [TREATMENT] [LIFT] [LIGATION OF INTERSPHINCTERIC FISTULA]. Primary healing and recurrence associated with surgical modifications were investigated.

RESULTS

4 out of 25 patients presented with early failure (84% primary success rate) after a median follow-up period of 7 months. The median time until recurrence was 105 days. The success rate after a redo ligation was 100%. Twenty-eight studies were included for review and divided into three groups depending on the technical variation of the used technique. The success rate was 74.2% for the LIFT group, 72.9% in the LIFT + group, and 77.5% in the mLIFT group p = .92.

CONCLUSION

LIFT is a feasible treatment option for primary and recurrent fistulas, with excellent success rates where fistula characteristics rather than chosen technique dictate the surgical outcome.

Treatments for the amelioration of persistent factors in complex anal fistula

Anal fistulae are abnormal hollow connections between the wall of the anal canal and the perianal skin around the anus that have remained a burden on the medical sector for centuries. The complexity of this disease is attributed to a number of factors such as the degree of associated sphincter muscle, concomitant illnesses, existence of multiple fistulous tracts and the number of previous interventions. Persistence of a complex anal fistula can cause a decline in patient's physical quality of life as well as impact on the psychological status of patients who often suffer from anxiety and depression. Surgical intervention remains the gold standard for treatment, however; the risk of incontinence and high recurrence potential has led to interest into developing alternative treatment approaches such as the use of biologics, bioactives and biomaterials. One potential reason for these varied outcomes could be the multifactorial interplay between genetic, immune-related, environmental, and microbial persistence factors on tissue regeneration. Recent observations have proposed that adverse inflammatory mediators may contribute more than microbial factors. The moderate to high success rates of biotechnological advances (mesenchymal stem cells and biomaterial scaffolds) show promise as therapies for the amelioration of adverse persistent factors while facilitating a means to closing the fistula tract. The purpose of this review is to outline recent advances in biologics and combination therapies to treat persistent factors associated with complex anal fistula.

Current concepts in the pathogenesis of cryptoglandular perianal fistula

Cryptoglandular perianal fistula is a common benign anorectal disorder that is managed mainly with surgery. A fistula is typically defined as a pathological communication between two epithelialized surfaces. More specifically, perianal fistula manifests as an abnormal tract between the anorectal canal and the perianal skin. Perianal fistulas are often characterized by significantly decreased patient quality of life. The cryptoglandular theory of perianal fistulas suggests their development from the proctodeal glands, which originate from the intersphincteric plane and perforate the internal sphincter with their ducts. Involvement of proctodeal glands in the inflammatory process could play a primary role in the formation of cryptoglandular perianal fistula. The objective of this narrative review was to investigate the current knowledge of the pathogenesis of cryptoglandular perianal fistula with the specific aims of characterizing the potential role of proinflammatory factors responsible for the development of chronic inflammation. Further studies are crucial to improve the therapeutic management of cryptoglandular perianal fistulas.

Chemical Ablation for Treating Anal Fistulas without Surgical Intervention: Long-Term Results

Purposes. This study aimed to evaluate long-term outcomes after the application of a corrosive chemical agent for ablation of epithelial tissue as a non-surgical treatment of anal fistulas. Methods. Adult patients with symptomatic perianal fistula were prospectively included in the study. The fistula tract was irrigated with a 5% silver nitrate solution. The primary outcome measured in this study was the rate of clinical healing after long-term follow-up. Factors that may affect healing were also analysed. Results. A total of 186 patients with anal fistula were analysed. After irrigation with silver nitrate, 82 (44%) patients had complete clinical healing during a median follow-up time of 50 (7-64) months. Patients with intermittent discharge had a significantly higher rate of complete clinical healing than those with continuous discharge (P < .04). Fistulas without abscesses or secondary tracts had a significantly higher rate of complete clinical healing than the other types (P = .007). Conclusion. Chemical ablation of the epithelium of the anal fistula yields promising long-term outcomes in the management of anal fistulas without surgical intervention.

Experimental model of anal fistula in rats

Introduction the management of anal fistula remains debatable. The lack of a standard treatment free of complications stimulates the development of new options.

Objective to develop an experimental model of anal fistula in rats.

Methods to surgically create an anal fistula in 10 rats with Seton introduced through the anal sphincter musculature.The animals were euthanized for histological fistula tract assessment.

Results all ten specimens histologically assessed had a lumen and surrounding granulation tissue. There was complete epithelialization of the tract in two samples, halfway epithelialization in one sample and epithelialization of only the outer portion in six samples. Epithelialization was not evident in one tract.

Conclusion anal fistulas in rats were histologically proved.

Lift and VAAFT for high trans-sphincteric anal fistula: a single center retrospective analysis

PURPOSE

The management of complex anal fistulas remains a challenge, mainly due to the considerable risk of incontinence. We compared LIFT and VAAFT in the treatment of complex anal fistulas in terms of healing time, recurrence, continence, morbidity, and postoperative pain, focusing also on patients with local abscess at the time of surgery.

METHODS

We include all patients with high trans-sphincteric anal fistula even with abscess at the time of surgery. Anorectal manometry, endoanal ultrasound, Cleveland Clinic fecal incontinence score, VAS score, and number of previous fistula treatment were recorded. The clinical examination defined healing, insufficiency or recurrence of the fistula.

RESULTS

Fifty-four consecutive patients are undergoing surgery: 26 patients underwent LIFT and 28 underwent VAAFT. During the 18 months of follow-up there were no differences in terms of AM, CCFIS and VAS scores. Days of healing, failure, and recurrence rate were comparable in both groups. The subgroup of patients with local abscess undergoing LIFT showed worse results in terms of failure and recurrence rate (p < 0.05).

CONCLUSIONS

Both techniques are safe and effective and can offer long-term benefits. LIFT should not be used as a first treatment in high trans-sphincteric fistula with perianal abscess.

Evaluation and management of perianal abscess and anal fistula: SICCR position statement

Perianal sepsis is a common condition ranging from acute abscess to chronic anal fistula. In most cases, the source is considered to be a non-specific cryptoglandular infection starting from the intersphincteric space. Surgery is the main treatment and several procedures have been developed, but the risks of recurrence and of impairment of continence still seem to be an unresolved issue. This statement reviews the pertinent literature and provides evidence-based recommendations to improve individualized management of patients.

PRIMARY SPHINCTEROPLASTY COMPARING TWO DIFFERENT STITCHES IN ANAL FISTULA TREATMENT: EXPERIMENTAL STUDY IN RATS

BACKGROUND

Anal fistula is by definition the communication between the rectum or anal canal with the perineal region, which may be epithelialized and has cryptoglandular origin in 90% of cases. There are a large number of techniques for successfully treating trans-sphincteric fistulas of 20-50%, including primary sphincteroplasty, but it is not clear whether the material used would influence the outcome.

AIM

To analyze the efficacy of polydioxanone and polypropylene wire in primary post-fistulotomy sphincteroplasty in the treatment of trans-sphincteric fistulas in rats.

METHODS

Thirty Wistar rats had transfixation of the anal sphincter with steel wire, which remained for 30 days for the development of the anal fistula. After this period, it was removed and four groups were formed: A (control) without treatment; B (fistulotomy) submitted to such procedure and curettage only; C (polidioxanone) in which sphincteroplasty was performed after fistulotomy with polydioxanone wire; D (polypropylene) submitted to the same treatment as group C, but with polypropylene wire. After 30 days, euthanasia and removal of the specimens were performed for qualitative histopathological analysis, measurement of the area between the muscular cables edges and evaluation of the degree of local fibrosis.

RESULTS

There was persistence of the anal fistula in all animals of group A. There were no significant differences between groups B, C and D regarding the distance of the muscular cables (p=0.078) and the degree of fibrosis caused by the different treatments (p=0.373).

CONCLUSIONS

There was no difference between polydioxanone and polypropylene wires in post-fistulotomy primary sphincteroplasty, and this technique was not superior to simple fistulotomy in relation to the distance of the muscular cables nor did it present differences in relation to the degree of local fibrosis.

Perianal fistulas and the lift procedure: results, predictive factors for success, and long-term results with subsequent treatment

Background

Treatment of a perianal fistula is difficult due to the risk of fecal incontinence and recurrence. The ligation of intersphincteric tract (LIFT) procedure is a sphincter-saving procedure associated with success rates ranging from 57 to 94%. The aim of our study was to find predictors for a favorable outcome of the LIFT procedure, evaluation of postoperative fecal incontinence, quality of life, and subsequent treatment with long-term follow-up.

Methods

This study was performed in patients who underwent LIFT between 2013 and 2015 at our institution. Their medical data were retrieved from the electronic patient files. The fistula characteristics were described by physical examination, three-dimensional endoanal ultrasound, and perioperative evaluation. Recurrence rate, postoperative fecal incontinence, and quality of life were assessed with the Patient-Reported Outcome Measurement (PROM). Thirty-two months later, long-term follow-up including subsequent procedures was evaluated.

Results

Forty-five patients [17 men, mean age 40 years (range 24–67 years)] were included. In 41 (84%) patients, the fistula was classified as complex; 32 (71%) were referrals with a history of previous fistula surgery. The initial success rate was 18 (40%). Only the height of the internal fistula opening (≥ 15 mm p < 0.03) was associated with recurrence. The LIFT procedure did not affect the occurrence of fecal incontinence or soiling. Recurrence showed a trend with a lower PROM (p = 0.07). Twenty-four months later, further surgery leads to cure in 34 (75%), asymptomatic fistulas in 7 (16%), and persisting active fistulas in 4 (9%) patients.

Conclusions

Initial LIFT had a success rate of 40% and with subsequent surgical treatment 75%. Recurrence after LIFT is related to the height of the internal fistula opening and is associated with diminished quality of life. Continence was not affected by initial LIFT.

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.

Review article: pathogenesis of Crohn's perianal fistula-understanding factors impacting on success and failure of treatment strategies

BACKGROUND

Evidence from groups who have studied fistula aetiology and extrapolation from interventional studies supports a multifactorial hypothesis of Crohn's perianal fistula, with several pathophysiological elements that may contribute to fistula formation, persistence and resistance to treatment.

AIM

An evidence synthesis of current understanding of pathophysiological factors underlying Crohn's perianal fistula is presented, exploring the fundamental reasons why some treatments succeed and others fail, as a means of focussing clinical knowledge on improving treatment of Crohn's perianal fistula.

METHODS

Evidence to support this review was gathered via the Pubmed database. Studies discussing pathophysiological factors underpinning perianal fistula, particularly in Crohn's disease, were reviewed and cross-referenced for additional reports.

RESULTS

Pathophysiological factors that impact on success or failure of interventions for Crohn's perianal fistulae include the high-pressure zone, obliterating the dead space, disconnecting the track from the anus, removing epithelialisation, eradicating sepsis and by-products of bacterial colonisation, correcting abnormalities in wound repair and removing the pro-inflammatory environment which allows fistula persistence. Most current interventions for Crohn's perianal fistulae tend to focus on a single, or at best two, aspects of the pathophysiology of Crohn's anal fistulae; as a result, failure to heal fully is common.

CONCLUSIONS

For an intervention or combination of interventions to succeed, multiple factors must be addressed. We hypothesise that correct, timely and complete attention to all of these factors in a multimodal approach represents a new direction that may enable the creation of an effective treatment algorithm for Crohn's anal fistula.

The treatment of anal fistula: second ACPGBI Position Statement - 2018

It is over 10 years since the first ACPGBI Position Statement on the management of anal fistula was published in 2007. This second edition is the result of scrutiny of the literature published during this time; it updates the original Position Statement and reviews the published evidence surrounding treatments for anal fistula that have been developed since the original publication.

Prognostic factors affecting outcomes in fistulating perianal Crohn's disease: a systematic review

BACKGROUND

One in three patients with Crohn's disease will develop a perianal fistulae, and one third of these will achieve long-term healing or closure. A barrier to conducting well-designed clinical trials for these patients is a lack of understanding of prognostic factors. This systematic review sets out to identify factors associated with prognosis of perianal Crohn's fistulae.

METHODS

This review was registered on the PROSPERO database (CRD42016050316) and conducted in line with PRISMA guidelines along a predefined protocol. English-language studies assessing baseline factors related to outcomes of fistulae treatment in adult patients were included. Searches were performed on MEDLINE and Embase databases. Screening of abstracts and full texts for eligibility was performed prior to extraction of data into predesigned forms. Bias was assessed using the QUIPS tool.

RESULTS

Searches identified 997 papers. Following removal of duplicates and secondary searches, 923 were screened for inclusion. Forty-seven papers were reviewed at full-text level and 13, 2 of which were randomised trials, were included in the final qualitative review. Two studies reported distribution of Crohn's disease as a prognostic factor for healing. Two studies found that CARD15 mutations decreased response of fistulae to antibiotics. Complexity of fistulae anatomy was implicated in prognosis by 4 studies.

CONCLUSIONS

This systematic review has identified potential prognostic markers, including genetic factors and disease behaviour. We cannot, however, draw robust conclusions from this heterogeneous group of studies; therefore, we recommend that a prospective cohort study of well-characterised patients with Crohn's perianal fistulae is undertaken.

Immunopathological characterization of cryptoglandular anal fistula: a pilot study investigating its pathogenesis

AIM

The pathogenesis of cryptoglandular anal fistula (AF) is still under debate. Tissue inflammation could play a primary role. The pathological process of epithelial mesenchymal transition (EMT) might be involved but has never been investigated.

METHOD

In a prospective pilot study, 12 patients with an AF had a fistulectomy. The excised track was divided into proximal (intrasphincteric) and distal (extrasphincteric) parts which were subjected to standard histopathological examination. The cytokines IL-8 and IL-1beta were analysed as markers of inflammation, while EMT was evaluated by expression of TGF-beta, Vimentin, Zeb-1, Snail and E-cadherin. The mRNA and protein expression of these molecules was investigated by real-time PCR (RT-PCR), Western blot analysis and immunohistochemistry and was compared with that of the normal adjacent tissue.

RESULTS

Chronic inflammation and granulation tissue and a stratified epithelium were evident on standard histopathological examination. The cytokine IL-8 was more expressed in the proximal than the distal part of the track (fold increase 4.34 vs 3.60), while the reverse was found for IL-1beta (fold increase 1.33 vs 2.01); both were more intensely expressed compared with the normal anal mucosa. EMT was demonstrated, in both proximal and distal parts of the track, with an increase of TGF-beta, Vimentin, Zeb-1 and Snail and a mean decrease of E-cadherin. Western blot analysis and immunohistochemistry confirmed the protein expression.

CONCLUSION

The study suggests that chronic inflammation is present in cryptoglandular fistulas. The inflammatory pattern might be different in the proximal than in the distal part of the fistula track. The cytokines IL-1beta and IL-8 could play a possible role in fistula formation. The study demonstrates for the first time the potential importance of EMT in the pathogenesis of cryptoglandular AF.

Pro-inflammatory cytokines in cryptoglandular anal fistulas

Background

Sphincter-preserving procedures for the treatment of transsphincteric fistulas fail in at least one out of every three patients. It has been suggested that failure is due to ongoing disease in the remaining fistula tract. Cytokines play an important role in inflammation. At present, biologicals targeting cytokines are available. Therefore, detection and identification of cytokines in anal fistulas might have implications for future treatment modalities. The objective of the present study was to assess local production of a selected panel of cytokines in anal fistulas, including pro-inflammatory interleukin (IL)-1β and tumor necrosis factor α (TNF-α).

Methods

Fistula tract tissue was obtained from 27 patients with a transsphincteric fistula of cryptoglandular origin who underwent flap repair, ligation of the intersphincteric fistula tract or a combination of both procedures. Patients with a rectovaginal fistula or a fistula due to Crohn’s disease were excluded. Frozen tissue samples were sectioned and stained using advanced immuno-enzyme staining methods for detection of selected cytokines, IL-1β, IL-8, IL-10, IL-12p40, IL-17A, IL-18, IL-36 and TNF-α. The presence and frequencies of cytokine-producing cells in samples were quantitated.

Results

The key finding was abundant expression of IL-1β in 93 % of the anal fistulas. Frequencies of IL-1β-producing cells were highest (>50 positive stained cells) in 7 % of the anal fistulas. Also, cytokines IL-8, IL-12p40 and TNF-α were present in respectively 70, 33 and 30 % of the anal fistulas.

Conclusions

IL-1β is expressed in the large majority of cryptoglandular anal fistulas, as well as several other pro-inflammatory cytokines.

Ligation of intersphincteric fistula tract: What is the evidence in a review?

Broadly, complex fistulas are those that are not low transsphincteric or intersphincteric. The objectives of surgical management are to achieve fistula healing, prevent recurrences and maintain continence. The risk of incontinence associated with treatment ranges from 10% to 57%. The objective of this manuscript is to review the current literature to date on the ligation of the intersphincteric fistula tract procedure (LIFT procedure) as a treatment option in these types of fistula. A search was conducted in Medline, PUBMED, EMBASE and ISI Web of Knowledge, and studies published from January 2009 to May 2013 were included. The primary outcomes were fistula healing rates, mean healing time and patient satisfaction with this surgical technique. Eighteen studies were included in this review. The total number of patients included was 592 (65% male). The median age reported was 42.8 years. The most common type of fistula included was transsphincteric (73.3% of cases). The mean healing rate reported was 74.6%. The risk factors for failure discovered were obesity, smoking, multiple previous surgeries and the length of the fistula tract. The mean healing time was 5.5 wk, and the mean follow-up period was 42.3 wk. The patient satisfaction rates ranged from 72% to 100%. No de novo incontinence developed secondary to the LIFT procedure. There is not enough evidence that variants in the surgical technique achieve better outcomes (Bio-LIFT, LIFT-Plug, LIFT-Plus). This review indicates that the LIFT procedure is primarily effective for transsphincteric fistulas with an overall fistula closure of 74.6% and has a low impact on fecal continence. This procedure produces better outcomes at the first surgical attempt.

Ligation of the intersphincteric fistula tract in low transsphincteric fistulae: a new technique to avoid fistulotomy

AIM

  To date fistulotomy is still the treatment of choice for patients with a transsphincteric fistula passing through the lower third of the external anal sphincter, because it is a simple, effective and safe procedure with a minimal risk of incontinence. However, data suggest that the risk of impaired continence following division of the lower third of the external anal sphincter is not insignificant, especially in female patients with an anterior fistula and patients with diminished anal sphincter function. It has been shown that ligation of the intersphincteric fistula tract (LIFT) is a promising sphincter-preserving technique. Therefore, we questioned whether LIFT could replace fistulotomy in patients with a low transsphincteric fistula.

METHOD

A consecutive series of 22 patients with a low transsphincteric fistula of cryptoglandular origin underwent LIFT. Continence scores were determined using the Rockwood Fecal Incontinence Severity Index.

RESULTS

  Median follow-up was 19.5months. Primary healing was observed in 18 (82%) patients. In the four patients without primary healing, the transsphincteric fistula was converted into an intersphincteric fistula. These patients underwent subsequent fistulotomy with preservation of the external anal sphincter. The overall healing rate was 100%. Six months after surgery, the median incontinence score was not changed significantly.

CONCLUSION

  Low transsphincteric fistulae can be treated successfully by LIFT, without affecting faecal continence. Division of the lower part of the external anal sphincter is no longer necessary in the treatment of low transsphincteric fistulae, which is essential for patients with compromised anal sphincters.

Assessment of microbiota and peptidoglycan in perianal fistulas

Transanal advancement flap repair has been advocated as the treatment of choice for high transsphincteric perianal fistulas, but fails in 1 of every 3 patients. Persistence of the fistula after flap repair might be the result of ongoing disease in the remaining fistula tract. In 10 specimens of the distal part of the fistula, microbiota was assessed by means of conventional microbiological culture and 16S rRNA gene sequencing. Proinflammatory bacterial peptidoglycan and recognition proteins were assessed by immunohistochemistry. Bacterial species were bowel derived, skin derived, or a combination of both. No mycobacterium species were identified. 16S rRNA gene sequencing failed to identify bacteria in all but 1 specimen, most likely as a result of low numbers of organisms. Peptidoglycan was detected in 90% of the patients, and a host response to peptidoglycan in 60%. Therefore, we suggest that peptidoglycan might play a role in the ongoing inflammation in perianal fistulas.