Structured magnetic resonance imaging and endoanal ultrasound anal fistulas reporting template(SMART):An interdisciplinary Delphi consensus

BACKGROUND There is still considerable heterogeneity regarding which features of cryptoglandular anal fistula on magnetic resonance imaging(MRI)and endoanal ultrasound(EAUS)are relevant to surgical decision-making.As a con-sequence,the quality and completeness of the report are highly dependent on the training and experience of the examiners.AIM To develop a structured MRI and EAUS template(SMART)reporting the minimum dataset of information for the treatment of anal fistulas.METHODS This modified Delphi survey based on the RAND-UCLA appropriateness for consensus-building was conducted between May and August 2023.One hundred and fifty-one articles selected from a systematic review of the lite-rature formed the database to generate the evidence-based statements for the Delphi study.Fourteen questions were anonymously voted by an interdisciplinary multidisciplinary group for a maximum of three iterative rounds.The degree of agreement was scored on a numeric 0–10 scale.Group consensus was defined as a score≥8 for≥80%of the panelists.RESULTS Eleven scientific societies(3 radiological and 8 surgical)endorsed the study.After three rounds of voting,the experts(69 colorectal surgeons,23 radiologists,2 anatomists,and 1 gastroenterologist)achieved consensus for 12 of 14 statements(85.7%).Based on the results of the Delphi process,the six following features of anal fistulas were included in the SMART:Primary tract,secondary extension,internal opening,presence of collection,coexisting le-sions,and sphincters morphology.CONCLUSION A structured template,SMART,was developed to standardize imaging reporting of fistula-in-ano in a simple,systematic,time-efficient way,providing the minimum dataset of information and visual diagram useful to refer-ring physicians.

High complex anal fistula managed by the modified transanal opening of the intersphincteric space via the inter-sphincteric approach:A case report

BACKGROUND High complex anal fistulas are epithelialized tunnels,with the main fistula piercing above the deep external sphincter and the internal opening approaching the dentate line.Conventional surgical procedures for high complex anal fistulas remove most of the external sphincter and damage the anorectal ring.Postoperative loss of anal function can cause physical and mental damage.Transanal opening of the intersphincteric space(TROPIS)is an effective procedure that completely preserves the external anal sphincter.However,its clinical application is limited by challenges in the localization of the internal opening of a fistula and the high risk of complications.On the basis of our clinical experience,we modified the TROPIS procedure for the treatment of treating high complex anal fistulas.CASE SUMMARY A patient with a high complex anal fistula located above the anorectal ring underwent modified TROPIS,which involved sepsis drainage and identification of the internal opening in the intersphincteric space.The patient with the high complex anal fistula recovered well postoperatively,without any postoperative complications or anal dysfunction.Anal function returned to normal after 17 months of follow-up.CONCLUSION The modified TROPIS procedure is the most minimally invasive surgery for anal fistulas that minimally impairs anal function.It allows the complete removal of infected anal glands and reduces the risk of postoperative complications.Modified TROPIS via the intersphincteric approach is an alternative sphincter-preserving treatment for high complex anal fistulas.

Clinical Study on the Treatment of Low Anal Fistula in Infants and Young Children by Anal Gland Excision and Virtual Hanging Procedure

Objective:To compare the efficacy of anal adenectomy with virtual hanging wire and anal fistulotomy in the treatment of low anal fistula in infants and children.Methods:60 children with low anal fistula who were admitted to our hospital from October 2021 to March 2022 and met the inclusion criteria were randomly divided into two groups of 30 cases each;the treatment group was treated with anal adenectomy and virtual hanging wire surgery,and the control group was treated with anal fistula resection.The clinical efficacy after treatment was compared.Results:The total effective rate of both groups was 96.67%and the difference between the two groups was not statistically significant(P>0.05).The postoperative pain score of the treatment group was lower than that of the control group(P<0.05).The length of hospitalization and healing time of the treatment group was lower than that of the control group(P<0.05).The anal function of the patients in both groups was normal,and there was no adverse reaction.Conclusion:Anal gland excision and virtual hanging surgery for the treatment of low anal fistula in infants and children have the advantages of mild pain,reduced length of hospitalization,short healing time,and better patient experience as compared to anal fistula excision.

A case study illustrating the use of an integrated approach to treat secondary Anal Fistula Post I&D of Perianal Abscess

Background:Anal fistula is a long-term disease characterized by a tubular structure with one end opening in the anorectal canal and the other end opening on the surface of the perineum or perianal skin with chronic pus drainage.It is linked to Bhagandar in Ayurveda,and in Sushruta Samhita,Acharya has mentioned 5 forms of Bhagandar.The boil in the present case was Shukla,sthira i.e.hard and firm,with Picchila strava and Kandu resembling the features of Parisraavi bhagandar.Aim and objective:The current case was diagnosed as Parisravi bhagandar,which resembles trans-sphincteric or intersphincteric fistula in modern ano.In Ayurveda,the management of Parisraavi Bhagandar,Shastra,kshara,and Agnikarma is advised and the use of Ksharasutra,which contributes to complete cutting and healing of the track without reoccurrence,similarly Modern surgeon depends on surgery i.e radical excision of the track,ligation with Seton,and use of chemical irritants like urethane,silver nitrates,etc.A cutting seton(tight)gently slices the confined muscle to close the fistula with the least interruption to continence.This operation is especially advised when a one-stage fistulotomy poses a considerable risk of incontinence.Material and methods:The method performed here was Core Partial Fistulectomy followed by Ksharasutra application till complete healing of the wound.Discussion and conclusion:This case study provides the successful management of Parisraavi Bhagandara(high anal,trans-sphincteric fistula in ano)in 61-year-old male patient with an integrated surgical&Ayurvedic management approach.

Modern management of anal fistula

Ideal surgical treatment for anal fistula should aim to eradicate sepsis and promote healing of the tract,whilst preserving the sphincters and the mechanism of continence.For the simple and most distal fistulae,conventional surgical options such as laying open of the fistula tract seem to be relatively safe and therefore,well accepted in clinical practise.However,for the more complex fistulae where a significant proportion of the anal sphincter is involved,great concern remains about damaging the sphincter and subsequent poor functional outcome,which is quite inevitable following conventional surgical treatment.For this reason,over the last twodecades,many sphincter-preserving procedures for the treatment of anal fistula have been introduced with the common goal of minimising the injury to the anal sphincters and preserving optimal function.Among them,the ligation of intersphincteric fistula tract procedure appears to be safe and effective and may be routinely considered for complex anal fistula.Another technique,the anal fistula plug,derived from porcine small intestinal submucosa,is safe but modestly effective in long-term follow-up,with success rates varying from 24%-88%.The failure rate may be due to its extrusion from the fistula tract.To obviate that,a new designed plug(GORE BioA ) was introduced,but long term data regarding its efficacy are scant.Fibrin glue showed poor and variable healing rate(14%-74%).Fi La C and video-assisted anal fistula treatment procedures,respectively using laser and electrode energy,are expensive and yet to be thoroughly assessed in clinical practise.Recently,a therapy using autologous adiposederived stem cells has been described.Their properties of regenerating tissues and suppressing inflammatory response must be better investigated on anal fistulae,and studies remain in progress.The aim of this present article is to review the pertinent literature,describing the advantages and limitations of new sphincterpreserving techniques.

Anal fistula plugvs mucosa advancement flap in complex fistula-in-ano:A meta-analysis

AIM:To investigate the efficacy of the anal fistula plug(AFP) compared to the mucosa advancement flap(MAF),considered the best procedure for patients with a complex anal fistula.METHODS:The literature search included PubMed,EMBASE,Cochrane Library and OVID original studies on the topic of AFP compared to MAF for complex fistula-in-ano that had a deadline for publication by April 2011.Randomized controlled trials,controlled clinical trials and prospective cohort studies were included in the review.After information collection,a meta-analysis was performed using data on overall success rates as well as incidence of incontinence and morbidity.The quality of postoperative life was also included with the clinical results.RESULTS:Six studies involving 408 patients(AFP = 167,MAF = 241) were included in the meta-analysis.The differences in the overall success rates and incidence of fistula recurrence were not statistically significant between the AFP and MAF [risk difference(RD) =-0.12,95%CI:-0.39-0.14;RD = 0.13;95%CI:-0.18-0.43,respectively].However,for the AFP,the risk of postoperative impaired continence was lower(RD =-0.08,95%CI:-0.15--0.02) as was the incidence of other complications(RD =-0.06,95%CI:-0.11-0.00).The postoperative quality of life,for patients treated using the AFP was superior to that of the MAF patients.Patients treated with the AFP had less persistent pain of a shorter duration and the healing time of the fistula and hospital stay were also reduced.CONCLUSION:The AFP is an effective procedure for patients with a complex anal fistula;it has the same success rate but a lower risk of complications than the MAF and may also be associated with an improved postoperative quality of life.Additional evidence is needed to confirm these findings.

PERFACT procedure:A new concept to treat highly complex anal fistula

AIM: To check the efficacy of the PERFACT procedure in highly complex fistula-in-ano.METHODS: The PERFACT procedure(proximal superficial cauterization, emptying regularly fistula tracts and curettage of tracts) entails two steps: superficial cauterization of mucosa at and around the internal opening and keeping all the tracts clean. The principle is to permanently close the internal opening by granulation tissue. This is achieved by superficial electrocauterization at and around the internal opening and subsequently allowing the wound to heal by secondary intention. Along with this, all the tracts are curetted and it is ensured that they remain empty and clean in the postoperative period until they heal completely. The latter step also facilitates the closure of the internal opening by preventing collected fluid in the tracts from entering the internal opening and thus not letting it close. Objective incontinence scoring was done preoperatively and 3 mo after the operation.RESULTS: Fifty-one patients with complex fistula-inano were prospectively enrolled. The median followup was 9 mo(5-14 mo). The mean age was 42.7 ± 11.3 years. Male:female ratio was 43:8. Fistula was recurrent in 76.5%(39/51), horseshoe in 50.1%(26/51), had multiple tracts in 52.9%(27/51), had an associated abscess in 41.2%(21/51), was anterior in 33.3%(17/51), the internal opening was not found in 15.7%(8/51) and 9.8%(5/51) of fistulas had a supralevator extension. Seven patients were excluded(5 lost to follow up, 2 with tuberculosis leading to/associated with fistula-in-ano). The success rate was 79.5%(35/44) and the recurrence rate was 20.5%(9/44). Out of these recurrences, three underwent reoperation(2 PERFACT procedure, 1 fistulotomy) and all three were successful. Thus, the overall success rate was 86.4%. The only complication was a non-healing tract in 9.1%(4/44) of patients. There was no significant change in objective incontinence scores three months after the operation. The pain was minimal, with all patients resuming their normal activities within 72 h of the operation.CONCLUSION: The PERFACT procedure is a new effective method for complex fistula-in-ano, effective even in fistula associated with abscess, supralevator fistula-in-ano and where the internal opening is nonlocalizable.

Why do we have so much trouble treating anal fistula?

Anal fistula is among the most common illnesses affecting man.Medical literature dating back to 400 BC has discussed this problem.Various causative factors have been proposed throughout the centuries,but it appears that the majority of fistulas unrelated to specific causes (e.g.Tuberculosis,Crohn’s disease) result from infection (abscess) in anal glands extending from the intersphincteric plane to various anorectal spaces.The tubular structure of an anal fistula easily yields itself to division or unroofing (fistulotomy) or excision (fistulectomy) in most cases.The problem with this single,yet effective,treatment plan is that depending on the thickness of sphincter muscle the fistula transgresses,the patient will have varying degrees of fecal incontinence from minor to total.In an attempt to preserve continence,various procedures have been proposed to deal with the fistulas.These include: (1) simple drainage (Seton);(2) closure of fistula tract using fibrin sealant or anal fistula plug;(3) closure of primary opening using endorectal or dermal flaps,and more recently;and (4) ligation of intersphincteric fistula tract (LIFT).In most complex cases (i.e.Crohn’s disease),a proximal fecal diversion offers a measure of symptom-atic relief.The fact remains that an "ideal" procedure for anal fistula remains elusive.The failure of each sphincter-preserving procedure (30%-50% recurrence) often results in multiple operations.In essence,the price of preservation of continence at all cost is multiple and often different operations,prolonged disability and disappointment for the patient and the surgeon.Nevertheless,the surgeon treating anal fistulas on an occasional basis should never hesitate in referring the patient to a specialist.Conversely,an expert colorectal surgeon must be familiar with many different operations in order to selectively tailor an operation to the individual patient.

Prevalence of anal fistula in the United Kingdom

BACKGROUND Anal fistula is a pathological connection between the anal canal and perianal skin, which most commonly develops from an infected anal crypt. While the majority of anal fistulas are idiopathic, they are also associated with Crohn’s disease (CD) and other inflammatory conditions. The prevalence of anal fistula is estimated to be 1-2 per 10000 patients, but population-based studies on anal fistula epidemiology are limited and outdated. AIM To assess the prevalence of anal fistula and relevant comorbidities, with and without CD in the United Kingdom and Europe. METHODS A retrospective population-representative observational cohort study was performed in The Health Improvement Network (THIN), a United Kingdom primary care database. Mid-year point prevalence of anal fistula was calculated on the first of July for each year between 2014 and 2017. Estimates were calculated for anal fistula overall and by CD status and standardized to the United Kingdom and European population. Prevalence of relevant comorbidities including lymphogranuloma venereum, hidradenitis suppurativa, anal presentation of sexually transmitted diseases, diabetes mellitus, and radiation in the pelvic area was reported. RESULTS The United Kingdom-standardized overall point prevalence of anal fistula was 1.80 (95%CI: 1.65-1.94) per 10000 patients in 2017, while the Europe standardized estimate was 1.83 (95%CI: 1.68-1.98) per 10000 patients. Both these standardized point prevalence estimates ranged from 1.89 to 2.36 between 2014-2016. The United Kingdom-standardized point prevalence of anal fistula without CD was 1.35 (95%CI: 1.23-1.48) per 10000 patients, while the Europe-standardized estimate was 1.39 (95%CI: 1.26-1.52) per 10000 patients. In contrast, the standardized point prevalence estimate of anal fistula with CD was lower for both United Kingdom and Europe (0.44;95%CI United Kingdom: 0.37-0.52, 95%CI Europe: 0.37-0.51) per 10000 patients in 2017. In 2017, 19% of anal fistula patients without CD and 13% of anal fistula patients with CD had at least one relevant comorbidity. These results show that anal fistulas are infrequent in the general population. 24.5% of prevalent anal fistulas are associated with CD, but other potentially etiological comorbidities are rare. CONCLUSION This real-world evidence study estimated the United Kingdom-standardized prevalence of anal fistula was 1.80 per 10000 patients in 2017. Approximately 25% of cases may be associated with CD, while other comorbidities are rare.

Treatment of peri-anal fistula in Crohn's disease

Anal fistulas are a common manifestation of Crohn's disease(CD). The first manifestation of the disease is often in the peri-anal region, which can occur years before a diagnosis, particularly in CD affecting the colon and rectum. The treatment of peri-anal fistulas is difficult and always multidisciplinary. The European guidelines recommend combined surgical and medical treatment with biologic drugs to achieve best results. Several different surgical techniques are currently em-ployed. However, at the moment, none of these tech-niques appear superior to the others in terms of healing rate. Surgery is always indicated to treat symptomatic, simple, low intersphincteric fistulas refractory to medi-cal therapy and those causing disabling symptoms. Ut-most attention should be paid to correcting the balance between eradication of the fistula and the preservationof fecal continence.

Three-dimensional endoanal ultrasonographic assessment of an anal fistula with and without H_2O_2 enhancement

AIM： To evaluate the effectiveness of three-dimensional endoanal ultrasound （3D-EAUS） in the assessment of anal fistulae with and without H202 enhancement. METHODS： Sixty-one patients （37 males, aged 17-74 years） with anal fistulae, which were not simple low types, were evaluated by physical examination and 3D-EAUS with and without enhancement. Fistula classification was determined with each modality and compared to operative findings as the reference standard. RESULTS： The accuracy of 3D-EAUS was significantly higher than that of physical examination in detecting the primary tract （84.4% vs 68.7%, P = 0.037） and secondary extension （81.8% vs 62.1%, P = 0.01） and localizing the internal opening （84.2% vs 59.7%, P = 0.004）. A contrast study with H202 detected several more fistula components including two primary suprasphincteric fistula tracks and one supralevator secondary extension, which were not detected on non-contrast study. However, there was no significant difference in accuracy between 3D-EAUS and H202- enhanced 3D-EAUS with respect to classification of the primary tract （84.4% vs 89.1%, P = 0.435） or secondary extension （81.8% vs 86.4%, P = 0.435） or localization of the internal opening （84.2% vs 89.5%, P = 0.406）. CONCLUSION： 3D-EAUS was highly reliable in the diagnosis of an anal fistula. H2O2 enhancement was helpful at times and selective use in difficult cases may be economical and reliable.

Anal fistula: Intraoperative difficulties and unexpected findings

Anal fistula surgery is a commonly performed procedure.The diverse anatomy of anal fistulae and their proximity to anal sphincters make accurate preoperative diagnosis essential to avoid recurrence and fecal incontinence.Despite the fact that proper preoperative diagnosis can be reached in the majority of patients by simple clinical examination,endoanal ultrasound or magnetic resonance imaging,on many occasions,unexpected findings can be encountered during surgery that can make the operation difficult and correct decision-making crucial.In this article we discuss the difficulties and unexpected findings that can be encountered during anal fistula surgery and how to overcome them.

Lessons learned from an audit of 1250 anal fistula patients operated at a single center:A retrospective review

BACKGROUND A complex anal fistula is a challenging disease to manage.AIM To review the experience and insights gained in treating a large cohort of patients at an exclusive fistula center.METHODS Anal fistulas operated on by a single surgeon over 14 years were analyzed.Preoperative magnetic resonance imaging was done in all patients.Four procedures were performed:fistulotomy;two novel sphincter-saving procedures,proximal superficial cauterization of the internal opening and regular emptying and curettage of fistula tracts(PERFACT)and transanal opening of intersphincteric space(TROPIS),and anal fistula plug.PERFACT was initiated before TROPIS.As per the institutional GFRI algorithm,fistulotomy was done in simple fistulas,and TROPIS was done in complex fistulas.Fistulas with associated abscesses were treated by definitive surgery.Incontinence was evaluated objectively by Vaizey incontinence scores.RESULTS A total of 1351 anal fistula operations were performed in 1250 patients.The overall fistula healing rate was 19.4%in anal fistula plug(n=56),50.3%in PERFACT(n=175),86%in TROPIS(n=408),and 98.6%in fistulotomy(n=611)patients.Continence did not change significantly after surgery in any group.As per the new algorithm,1019 patients were operated with either the fistulotomy or TROPIS procedure.The overall success rate was 93.5%in those patients.In a subgroup analysis,the overall healing rate in supralevator,horseshoe,and fistulas with an associated abscess was 82%,85.8%,and 90.6%,respectively.The 90.6%healing rate in fistulas with an associated abscess was comparable to that of fistulas with no abscess(94.5%,P=0.057,not significant).CONCLUSION Fistulotomy had a high 98.6%healing rate in simple fistulas without deterioration of continence if the patient selection was done judiciously.The sphincter-sparing procedure,TROPIS,was safe,with a satisfactory 86%healing rate for complex fistulas.This is the largest anal fistula series to date.

Recurrent anal fistulas: When, why, and how to manage?

Anal fistula is a commonly encountered anal condition in the surgical practice.Despite being a benign condition,anal fistula remains to represent a surgical challenge,particularly the complex type of fistulas.One of the common complications of anal fistula surgery is the persistence or recurrence of the pathology,both defined as failure of surgery.Recurrent anal fistulas after previous surgery represent an even more challenging problem since they are usually associated with a higher risk of re-recurrence and continence disturbance.The present review aimed to shed light on various aspects of recurrent anal fistulas,including the different definitions of failure after surgery,risk factors of recurrence,problems associated with management of recurrent fistulas,and assessment and treatment of recurrent anal fistulas.

Guidelines on postoperative magnetic resonance imaging in patients operated for cryptoglandular anal fistula:Experience from 2404 scans

Magnetic resonance imaging(MRI)is considered the gold standard for the evaluation of anal fistulas.There is sufficient literature available outlining the interpretation of fistula MRI before performing surgery.However,the interpretation of MRI becomes quite challenging in the postoperative period after the surgery of fistula has been undertaken.Incidentally,there are scarce data and no set guidelines regarding analysis of fistula MRI in the postoperative period.In this article,we discuss the challenges faced while interpreting the postoperative MRI,the timing of the postoperative MRI,the utility of MRI in the postoperative period for the management of anal fistulas,the importance of the active involvement and experience of the treating clinician in interpreting MRI scans,and the latest advancements in the field.

Prospective evaluation of a new device for the treatment of anal fistulas

AIM: To evaluate the safety of the implantation of a new device for the treatment of anal fistulas. The short-term clinical efficacy was also assessed. METHODS: This study took place at a tertiary care university hospital. Patients with a complex anal fistula of cryptoglandular origin were enrolled in the study and were treated with insertion of the new device. All patients were evaluated by clinical and physical examination, including an endoanal ultrasound at the baseline, and then at the 2 wk and 1, 2, 3 and 6-mo follow-up visits. RESULTS: Morbidity, continence status, and success rate were the main outcome measures. Ten patients underwent the placement of the new device. The fistulas were transphincteric in eight patients and extrasphincteric in the remaining two. The median duration of the surgical procedure was 34.5(range, 27-42) min. Neither intra- nor postoperative complications occurred, and all patients were discharged the day after the procedure. At the 6-mo follow-up evaluation, the final success rate was 70%. Three failures were registered: a device expulsion(on the 10 th postoperative day), the persistence of inflammatory tissue around the fistula tract(at the 2-mo follow up), and the persistence of serum discharge(at the 6-mo follow up). No patient experienced any change incontinence, as assessed by the Cleveland Clinic Fecal Incontinence score. CONCLUSION: The technical procedure is simple and has low risk of perioperative morbidity. The pre- and post-operative continence status did not change in any of the patients. The initial results at the 6-mo follow up seem to be promising. However, a longer follow-up period and a larger sample size are needed to confirm these preliminary results.

Traditional Chinese surgical treatment for anal fistulae with secondary tracks and abscess

AIM:To evaluate the efficacy and safety of traditional Chinese surgical treatment for anal fistulae with secondary tracks and abscess.METHODS:Sixty patients with intersphincteric or transsphincteric anal fistulas with secondary tracks and abscess were randomly divided into study group [suture dragging combined with pad compression(SDPC)] and control group [fistulotomy(FSLT)].In the SDPC group,the internal opening was excised and incisions at external openings were made for drainage.Silk sutures were put through every two incisions and knotted in loose state.The suture dragging process started from the first day after surgery and the pad compression process started when all sutures were removed as wound tissue became fresh and without discharge.In the FSLT group,the internal opening and all tracts were laid open and cleaned by normal saline postoperatively till all wounds healed.The time of healing,postoperative pain score(visual analogue scale),recurrence rate,patient satisfaction,incontinence evaluation and anorectal manometry before and after the treatment were examined.RESULTS:There were no significant differences between the two groups regarding age,gender and fistulae type.The time of healing was significantly shorter(24.33 d in SDPC vs 31.57 d in FSLT,P < 0.01) and the patient satisfaction score at 1 mo postoperative followup was significantly higher in the SDPC group(4.07 in SDPC vs 3.37 in FSLT,P < 0.05).The mean maximal postoperative pain scores were 5.83 ± 2.5 in SDPC vs 6.37 ± 2.33 in FSLT and the recurrence rates were 3.33 in SDPC vs 0 in FSLT.None of the patients in the two groups experienced liquid and solid fecal incontinence and lifestyle alteration postoperatively.The Wexner score after treatment of intersphincter fistulae were 0.17 ± 0.41 in SDPC vs 0.40 ± 0.89 in FSLT and transsphincter fistulae were 0.13 ± 0.45 in SDPC vs 0.56 ± 1.35 in FSLT.The maximal squeeze pressure and resting pressure declined after treatment in both groups.The maximal anal squeeze pressures after treatment were reduced(23.17 ± 3.73 Kpa in SDPC vs 22.74 ± 4.47 Kpa in FSLT) and so did the resting pressures(12.36 ± 2.15 Kpa in SDPC vs 11.71 ± 1.87 Kpa in FSLT),but there were neither significant differences between the two groups and nor significant differences before or after treatment.CONCLUSION:Traditional Chinese surgical treatment SDPC for anal fistulae with secondary tracks and abscess is safe,effective and less invasive.

Stem cell injection for complex anal fistula in Crohn’s disease: A single-center experience

BACKGROUND Despite tremendous progress in medical therapy and optimization of surgical strategies,considerable failure rates after surgery for complex anal fistula in Crohn’s disease have been reported.Therefore,stem cell therapy for the treatment of complex perianal fistula can be an innovative option with potential long-term healing.AIM To evaluate the results of local administration of allogenic,adipose-derived mesenchymal stem cells(darvadstrocel)for complex anal Crohn’s fistula.METHODS All patients with complex anal fistulas associated with Crohn’s disease who were amenable for definite fistula closure within a defined observation period were potential candidates for stem cell injection(darvadstrocel)if at least one conventional or surgical attempt to close the fistula had failed.Darvadstrocel was only indicated in patients without active Crohn’s disease and without presence of anorectal abscess.Local injection of darvadstrocel was performed as a standardized procedure under general anesthesia including single-shot antibiotic prophylaxis,removal of seton drainage,fistula curettage,closure of the internal openings and local stem cell injection.Data collection focusing on healing rates,occurrence of abscess and follow-up was performed on a regular basis of quality control and patient care.Data were retrospectively analyzed.RESULTS Between July 2018 and January 2021,12 patients(6 females,6 males)with a mean age of 42.5(range:26-61)years underwent stem cell therapy.All patients had a minimum of one complex fistula,including patients with two complex fistulas in 58.3%(7/12).Two of the 12 patients had horse-shoe fistula and 3 had one complex fistula.According to Parks classification,the majority of fistulas were transsphincteric(76%)or suprasphincteric(14%).All patients underwent removal of seton,fistula curettage,transanal closure of internal opening by suture(11/12)or mucosal flap(1/12)and stem cell injection.At a mean follow-up of 14.3(range:3-30)mo,a healing rate was documented in 66.7%(8/12);mean duration to achieve healing was 12(range:6-30)wk.Within follow-up,4 patients required reoperation due to perianal abscess(33.3%).Focusing on patients with a minimum follow-up of 12 mo(6/12)or 24 mo(4/12),long-term healing rates were 66.7%(4/6)and 50.0%(2/4),respectively.CONCLUSION Data of this single-center experience are promising but limited due to the small number of patients and the retrospective analysis.

Comparison between recent sphincter-sparing procedures for complex anal fistulas-ligation of intersphincteric tract vs transanal opening of intersphincteric space

Complex anal fistulas are difficult to treat.The main reasons for this are a higher recurrence rate and the risk of disrupting the continence mechanism because of sphincter involvement.Due to this,several sphincter-sparing procedures have been developed in the last two decades.Though moderately successful in simple fistulas(50%-75%healing rate),the healing rates in complex fistulas for most of these procedures has been dismal.Only two procedures,ligation of intersphincteric fistula tract and transanal opening of intersphincteric space have been shown to have good success rates in complex fistulas(60%-95%).Both of these procedures preserve continence while achieving high success rates.In this opinion review,I shall outline the history,compare the pros and cons,indications and contraindications and future application of both these procedures for the management of complex anal fistulas.

Guidelines to diagnose and treat peri-levator high-5 anal fistulas: Supralevator, suprasphincteric, extrasphincteric, high outersphincteric, and high intrarectal fistulas

Supralevator,suprasphincteric,extrasphincteric,and high intrarectal fistulas(high fistulas in muscle layers of the rectal wall)are well-known high anal fistulas which are considered the most complex and extremely challenging fistulas to manage.Magnetic resonance imaging has brought more clarity to the pathophysiology of these fistulas.Along with these fistulas,a new type of complex fistula in high outersphincteric space,a fistula at the roof of ischiorectal fossa inside the levator ani muscle(RIFIL),has been described.The diagnosis,management,and prognosis of RIFIL fistulas is reported to be even worse than supralevator and suprasphincteric fistulas.There is a lot of confusion regarding the anatomy,diagnosis,and management of these five types of fistulas.The main reason for this is the paucity of literature about these fistulas.The common feature of all these fistulas is their complete involvement of the external anal sphincter.Therefore,fistulotomy,the simplest and most commonly performed procedure,is practically ruled out in these fistulas and a sphincter-saving procedure needs to be performed.Recent advances have provided new insights into the anatomy,radiological modalities,diagnosis,and management of these five types of high fistulas.These have been discussed and guidelines formulated for the diagnosis and treatment of these fistulas for the first time in this paper.