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

Activated HLA-DR+CD38+ Effector Th1/17 Cells Distinguish Crohn's Disease-associated Perianal Fistulas from Cryptoglandular Fistulas

BACKGROUND

Perianal fistulas are a debilitating complication of Crohn's disease (CD). Due to unknown reasons, CD-associated fistulas are in general more difficult to treat than cryptoglandular fistulas (non-CD-associated). Understanding the immune cell landscape is a first step towards the development of more effective therapies for CD-associated fistulas. In this work, we characterized the composition and spatial localization of disease-associated immune cells in both types of perianal fistulas by high-dimensional analyses.

METHODS

We applied single-cell mass cytometry (scMC), spectral flow cytometry (SFC), and imaging mass cytometry (IMC) to profile the immune compartment in CD-associated perianal fistulas and cryptoglandular fistulas. An exploratory cohort (CD fistula, n = 10; non-CD fistula, n = 5) was analyzed by scMC to unravel disease-associated immune cell types. SFC was performed on a second fistula cohort (CD, n = 10; non-CD, n = 11) to comprehensively phenotype disease-associated T helper (Th) cells. IMC was used on a third cohort (CD, n = 5) to investigate the spatial distribution/interaction of relevant immune cell subsets.

RESULTS

Our analyses revealed that activated HLA-DR+CD38+ effector CD4+ T cells with a Th1/17 phenotype were significantly enriched in CD-associated compared with cryptoglandular fistulas. These cells, displaying features of proliferation, regulation, and differentiation, were also present in blood, and colocalized with other CD4+ T cells, CCR6+ B cells, and macrophages in the fistula tracts.

CONCLUSIONS

Overall, proliferating activated HLA-DR+CD38+ effector Th1/17 cells distinguish CD-associated from cryptoglandular perianal fistulas and are a promising biomarker in blood to discriminate between these 2 fistula types. Targeting HLA-DR and CD38-expressing CD4+ T cells may offer a potential new therapeutic strategy for CD-related fistulas.

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.

Fistulectomy and primary sphincteroplasty in complex anal fistula treatment: a hospital-based long-term follow-up study

BACKGROUND

Currently, there is no agreement on the best treatment for complex anal fistulas with the least recurrence and lowest complication rate. The aim of this study was to evaluate the long-term recurrence and incontinence after fistulectomy and primary sphincteroplasty (FIPS) in a group of patients with complex perianal fistula.

METHODS

This prospective observational study was done at the colorectal ward of Taleghani Hospital of Tehran from January 2010 to December 2020. Patients with anal fistula who underwent FIPS were studied. After surgery, patients were evaluated regularly by a colorectal surgeon for fistula recurrence and incontinence. Recurrence was described as a new fistula tract formation after the initial cure and failure of healing in the operation site or any purulent discharge from the fistula tract and openings. In addition, the patient's continence was assessed based on the Wexner score.

RESULTS

There were 335 patients (66 men and 269 women, mean age 42.74 ± 12.44 years), 191 of them with low fistula and 144 with high fistula. Thirteen patients (3.90%) experienced recurrence (all had a low fistula). Thirty-nine patients (11.64%), 19 patients with high and 20 patients with low fistula, had a Wexner score ≥ 3 during the follow-up. Fifteen patients were lost to follow-up. Male patients (OR = 2.67, 95% CI 0.84, 8.45, p = 0.094, adjusted OR = 4.41, 95% CI 1.05, 18.48, p = 0.042), patients with low fistula (p = 0.001), and recurrent cases had a significantly higher rate of recurrence (OR = 10.38, 95% CI 3.24-33.20 p ≤ 0.001, adjusted OR = 23.36, 95% CI 4.35-125.39, p ≤ 0.001). A significant correlation between body mass index > 35 kg/m² and incontinence was found (OR = 4.40, 95% CI 1.35, 14.33, p = 0.014).

CONCLUSIONS

In the present study, an acceptable healing rate and a low percentage of complications following FIPS were seen in patients with complex anal fistula. Randomized clinical trials with appropriate follow-up duration and sample size comparing different surgical methods in these patients are needed to confirm these results.

Serum Depletion of Complement Component 5a Is Associated With Increased Inflammation and Poor Clinical Outcomes in Patients With Perianal Fistulas

BACKGROUND

Persistent disease is a significant issue in the management of perianal fistulas, with up to 50% of patients requiring additional treatment after surgery.

OBJECTIVE

This study aimed to identify a novel prognostic modality in hopes of risk-stratifying patients for persistent disease following corrective surgery.

DESIGN

This was a retrospective study based on prospectively collected data using a combination of histopathology, high-throughput proteomic arrays, and ELISA-based methods.

SETTINGS

This study used data obtained from patients who underwent corrective surgery for perianal fistulas at the University of Illinois Hospital between June 2019 and July 2020.

PATIENTS

A cohort of 22 consecutive patients who had corrective surgery for perianal fistulas were included in this study. The patients were divided into 2 groups: those with resolving fistulas (N = 13) and those with persisting fistulas (N = 9).

MAIN OUTCOME MEASURES

Nonresolving fistulas were determined by disease representation within 2 months of corrective surgery.

RESULTS

Serum samples from patients with persistent perianal fistulas displayed a consistent decrease in the expression of complement pathway component C5a compared with either healthy controls or patients with resolving forms of disease. This was paralleled by an increase in the fistula expression of C5a and an associated increase in tissue infiltrating leukocytes and interleukin-1β expression.

LIMITATIONS

This study was limited by its retrospective design, relatively small sample size, and single-center data analysis.

CONCLUSIONS

These results suggest that C5a is modestly depleted in patients with nonresolving forms of disease and traffics to the site of tissue damage and inflammation. Accordingly, serum C5a warrants continued investigation as a prognostic biomarker and predictor of recurrence in patients presenting with perianal fistulas. See Video Abstract at http://links.lww.com/DCR/B982 .

LA DEPLECIN SRICA DEL COMPONENTE A DEL COMPLEMENTO SE ASOCIA CON UN AUMENTO DE LA INFLAMACIN Y MALOS RESULTADOS CLNICOS EN PACIENTES CON FSTULAS PERIANALES

ANTECEDENTES:La persistencia de la enfermedad es un problema significativo en el manejo de las fístulas perianales, presente hasta en el 50 % de los pacientes después de la cirugía y que requieren tratamiento adicional.OBJETIVO:DISEÑO:Se trata de un estudio retrospectivo basado en datos recolectados prospectivamente usando una combinación de histopatología, arreglos proteómicos de alto rendimiento y métodos basados en ELISA.ENTORNO CLÍNICO:Este estudio utilizó datos de pacientes que se sometieron a cirugía correctiva por fístulas perianales en el Hospital de la Universidad de Illinois entre junio de 2019 y julio de 2020.PACIENTES:Se incluyó en este estudio una cohorte de 22 pacientes consecutivos que se sometieron a cirugía correctiva de fístulas perianales. Los pacientes se dividieron en 2 grupos: aquellos con fístulas en resolución (N = 13) y aquellos con fístulas persistentes (N = 9).PRINCIPALES MEDIDAS DE VALORACIÓN:Las fístulas que no se resuelven fueron determinadas por la reaparición de la enfermedad dentro de los 2 meses posteriores a la cirugía correctiva.RESULTADOS:Las muestras de suero de pacientes con fístulas perianales persistentes mostraron una disminución constante en la expresión del componente C5a de la vía del complemento en comparación con controles sanos o pacientes con formas de resolución de la enfermedad. Esto fue paralelo a un aumento en la expresión de C5a en la fístula y un aumento asociado en los leucocitos que se infiltran en el tejido y la expresión de IL-1β.LIMITACIONES:El estudio estuvo limitado por su diseño retrospectivo, tamaño de muestra relativamente pequeño y análisis de datos de un solo centro.CONCLUSIONES:Estos resultados sugieren que C5a se reduce moderadamente en pacientes con formas de enfermedad que no se resuelven y se desplaza al sitio del daño tisular e inflamación. En consecuencia, el C5a sérico justifica una investigación continua como biomarcador pronóstico y predictor de recurrencia en pacientes que presentan fístulas perianales. Consulte Video Resumen en http://links.lww.com/DCR/B982 . (Traducción- Dr. Ingrid Melo ).

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.

Subcutaneous incision of the fistula tract and internal sphincterotomy (SIFT-IS): a novel surgical procedure for transsphincteric anal fistula

AIM

The aetiology of anal fistula has not been fully clarified. One of the causes of anal fistulas may be the markedly deep crypts that characterize the primary openings. We developed subcutaneous incision of the fistula tract and internal sphincterotomy (SIFT-IS) to eradicate these deep crypts. The aim of this study was to evaluate outcomes in patients with anal fistula treated with SIFT-IS.

METHOD

A retrospective study was performed over a 2-year period. Patients with transsphincteric anal fistula who underwent SIFT-IS were enrolled. The primary endpoint was the anal fistula healing rate at 16 weeks postoperatively. The secondary endpoints were healing time, postoperative complications and clinical continence status.

RESULTS

One hundred and fifty one patients were enrolled. Primary healing was accomplished in 129 patients (85%). There were 17 patients (11%) with a remnant fistula and five (3%) with a recurrence. The remnant fistulas healed spontaneously at more than 16 weeks postoperatively in seven patients. The median healing time was 6 (3-96) weeks. Surgical intervention was required in seven patients with a remnant fistula and four with recurrence. At the final follow-up, the wounds had healed in 148 patients (98%). No significant postoperative complications or incontinence were observed.

CONCLUSION

Subcutaneous incision of the fistula tract and internal sphincterotomy is a promising surgical option for transsphincteric anal fistulas, with a satisfactory healing rate.

Pathogenesis of Fistulating Crohn's Disease: A Review

Sustained, transmural inflammation of the bowel wall may result in the development of a fistula in Crohn's disease (CD). Fistula formation is a recognized complication and cause of morbidity, occurring in 40% of patients with CD. Despite advanced treatment, one-third of patients experience recurrent fistulae. Development of targeting treatment for fistulae will be dependent on a more in depth understanding of its pathogenesis. Presently, pathogenesis of CD-associated fistulae remains poorly defined, in part due to the lack of accepted in vitro tissue models recapitulating the pathogenic cellular lesions linked to fistulae and limited in vivo models. This review provides a synthesis of the existing knowledge of the histopathological, immune, cellular, genetic, and microbial contributions to the pathogenesis of CD-associated fistulae including the widely accredited contribution of epithelial-to-mesenchymal transition, upregulation of matrix metalloproteinases, and overexpression of invasive molecules, resulting in tissue remodeling and subsequent fistula formation. We conclude by exploring how we might utilize advancing technologies to verify and broaden our current understanding while exploring novel causal pathways to provide further inroads to future therapeutic targets.

Anal Fistula Human Amniotic Membrane Endosealing (F-HAME): A Proof of Concept Study

The treatment of cryptoglandular anal fistula (AF) is often a challenge for surgeons. Several sphincter-saving procedures have been described as an alternative to fistulotomy, with the common goal of promoting healing and preserve anal continence. The aim of this proof of concept study was to assess the outcomes of human amniotic membrane (HAM) implantation in cryptoglandular transphincteric AF. Two consecutive female were recruited. The primary outcome was clinical healing at 6 months. Secondary outcomes were ultrasonographic healing, complications and reinterventions, AF symptoms, fecal incontinence, psychological impact of treatment, recurrence, development of additional AF, patient satisfaction, and quality of life, as measured using validated questionnaires. Both patients (40 and 54-year-old) previously underwent incision and drainage of anal abscess with concomitant seton placement. HAM implantation was performed as a day case under local anesthesia. No intra- or post-procedural complications occurred. Clinical and radiological healing were not achieved at 6 months. However, the external outlet discharge diminished through time, with sustained improvements in quality of life. Clinical healing occurred at 7 months in both patients. Psychological impact of treatment and patient satisfaction were overall good, with improvements in the PHQ-9, GAD-7, and Short Assessment of Patients Satisfaction. HAM implantation is safe and improves patients' quality of life, progressively leading to clinical healing. Future studies are needed to assess its safety in other etiology of AF.

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.

Differences in amino acid and lipid metabolism distinguish Crohn's from idiopathic/cryptoglandular perianal fistulas by tissue metabonomic profiling and may offer clues to underlying pathogenesis

INTRODUCTION

Few studies have investigated perianal fistula etiopathogenesis, and although the cryptoglandular theory is widely accepted in idiopathic cases, in Crohn's disease, it is thought to involve the interplay between microbiological, immunological and genetic factors. A pilot study was conducted to assess for metabolic variations in Crohn's perianal fistula tissue that might differ from that of idiopathic (cryptoglandular) perianal fistula tissue as a comparator. The goal was to identify any potential biomarkers of disease, which may improve the understanding of pathogenesis.

AIMS AND METHODS

Fistula tract biopsies were obtained from 30 patients with idiopathic perianal fistula and 20 patients with Crohn's anal fistula. Two different assays were used in an ultra-high-performance liquid chromatography system coupled with a mass spectrometric detector to achieve broad metabolome coverage. Univariate and multivariate statistical data analyses were used to identify differentiating metabolic features corresponding to the perianal fistula phenotype (i.e. Crohn's disease vs. idiopathic).

RESULTS

Significant orthogonal partial least squares discriminant analysis predictive models (validated with cross-validated-analysis of variance P value <0.05) differentiated metabolites from tissue samples from Crohn's vs. idiopathic anal fistula patients using both metabolic profiling platforms. A total of 41 metabolites were identified, suggesting alterations in pathways, including amino acid, carnitine and lipid metabolism.

CONCLUSION

Metabonomics may reveal biomarkers of Crohn's perianal fistula. Further work in larger numbers is required to validate the findings of these studies as well as cross-correlation with microbiome work to better understand the impact of host-gut/environment interactions in the pathophysiology of Crohn's and idiopathic perianal fistulas and identify novel therapeutic targets.

Journey through Crohn's Disease Complication: From Fistula Formation to Future Therapies

Crohn’s Disease (CD) is a chronic inflammatory disorder in which up to 50% of patients develop fistula within 20 years after the initial diagnosis, and half of these patients suffer perianal fistulizing disease. The etiopathogenesis of CD-related perianal fistula is still unclear, and its phenotypical and molecular characteristics are even more indefinite. A better understanding would be crucial to develop targeted and more effective therapeutic strategies. At present, the most accredited theory for the formation of CD-related fistula identifies the epithelial-to-mesenchymal transition (EMT) as the driving force. It has been well recognized that CD carries an increased risk of malignancy, particularly mucinous adenocarcinoma is often associated with long-standing fistula in CD patients. Despite the availability of multiple treatment options, perianal fistulizing CD represents a therapeutic challenge and is associated with an important impact on patients’ quality of life. To date, the most effective management is multidisciplinary with the cooperation of gastroenterologists, surgeons, radiologists, and nutritionists and the best recommended treatment is a combination of medical and surgical approaches.

Efficacy and safety of autologous adipose-derived stromal vascular fraction enriched with platelet-rich plasma in flap repair of transsphincteric cryptoglandular fistulas

Background

Transanal advancement flap repair of transsphincteric fistulas is a sphincter-preserving procedure, which frequently fails, probably due to ongoing inflammation in the remaining fistula tract. Adipose-derived stromal vascular fraction (SVF) has immunomodulatory properties promoting wound healing and suppressing inflammation. Platelet-rich plasma (PRP) reinforces this biological effect. The aim of this study was to evaluate the efficacy and safety of autologous adipose-derived SVF enriched with PRP in flap repair of transsphincteric cryptoglandular fistulas.

Methods

A prospective cohort study was conducted including consecutive patients with transsphincteric cryptoglandular fistula in a tertiary referral center. During flap repair, SVF was obtained by lipoharvesting and mechanical fractionation of adipose tissue and combined with PRP was injected around the internal opening and into the fistulous wall. Endpoints were fistula healing at clinical examination and fistula closure on postoperative magnetic resonance imaging (MRI). Adverse events were documented.

Results

Forty-five patients with transsphincteric cryptoglandular fistula were included (29 males, median age 44 years [range 36–53 years]). In the total study population, primary fistula healing was observed in 38 patients (84%). Among the 42 patients with intestinal continuity at time of surgery, primary fistula healing was observed in 35 patients (84%). In one patient, the fistula recurred, resulting in a long-term healing rate of 82%. MRI, performed in 37 patients, revealed complete closure of the fistula tract in 33 (89.2%). In the other patients, the tract was almost completely obliterated by scar tissue. During follow-up, none of these patients showed clinical signs of recurrence. The postoperative course was uneventful, except for three cases; venous thromboembolism in one patient and bleeding under the flap, necessitating intervention in two patients.

Conclusions

Addition of autologous SVF enriched with PRP during flap repair is feasible, safe and might improve outcomes in patients with a transsphincteric cryptoglandular fistula.

Trial registration

Dutch Trial Register, Trial Number: NL8416, https://www.trialregister.nl/

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.

Effectiveness of infliximab treatment of complex idiopathic anal fistulas

OBJECTIVES

To investigate the effects of infliximab treatment in patients with complex idiopathic anal fistulas refractory to standard surgical treatment.

MATERIALS AND METHODS

We retrospectively evaluated the effects ofinfliximab treatmentin patients with complex idiopathic anal fistulas refractory to standard surgical intervention. The primary outcome was achievement of substantial clinical improvement defined as sustained, reduced inflammatory activity at perioperativeevaluation, i.e., only minimal-to-moderate secretion and induration and a reduction of fistula size of a magnitude that would make it possible to perform a lay-open or sphincter-sparring closure procedure. Secondary outcomes weresymptom improvement, adverse treatment events and fistula healing after the surgical procedure in those achieving the primary outcome.

RESULTS

Twenty-two patients were included (18 high transsphincteric, 3complex low transsphincteric, 1 suprasphincteric fistula). Fistulas had been present for a median of 24 [interquartile range, IQR: 12-33] months. In total, 16 patients (73%) achieved the primary outcome of substantial clinical improvement. Median time from infliximab initiation to patients achieved the primary outcome was 11 [IQR: 8-22] months. Sixteen of the patients responding to infliximab received subsequent lay-open or sphincter-sparring closure procedure surgery. Of these, ten (63%) achieved fistula healing. No serious infectious complications to infliximab treatment were seen. One patient developed a new abscess. One patient developed psoriasis (pustolosispalmoplantaris).

CONCLUSIONS

Infliximab treatment may be considered a supplement to repeated curettage and setondrainage in the management of selected, complex idiopathic anal fistulas. Such combined treatment may make otherwise refractory fistulas amenable to definitive closure attempts.

Ligation of the Intersphincteric Fistula Tract for High Transsphincteric Fistula Yields Moderate Results at Best: Is the Tide Turning?

BACKGROUND

Ligation of the intersphincteric fistula tract is a well-accepted and often used surgical procedure for perianal fistulas.

OBJECTIVE

This study aims to confirm results of the ligation of the intersphincteric fistula tract in a specialized colorectal center.

DESIGN

This is a retrospective cohort study.

SETTING

This study took place in a large colorectal surgical department with a tertiary referral center for perianal fistulas.

PATIENTS

Consecutive patients were operated on with ligation of the intersphincteric fistula tract for a transsphincteric perianal fistula between 2012 and December 2018.

INTERVENTIONS

Patients underwent ligation of the intersphincteric fistula tract.

MAIN OUTCOME MEASURES

The primary outcome measured was the healing rate. The secondary outcomes measured were conversion into an intersphincteric perianal fistula, risk of recurrence, complications, and postoperative continence status.

RESULTS

Forty-six patients were treated with a ligation of intersphincteric fistula tract procedure. All patients (100%) had preoperative imaging in their workup. Forty patients (87%) had a high transsphincteric fistula. The primary healing rate was a disappointing 17 of 46 patients (37%). The median time until failure was 4.2 months (interquartile range, 3.5-6.5). Of the failures, 16 converted to an intersphincteric fistula (55% of failures and 35% of all patients). The mean duration of follow-up in patients without a recurrence was 9.5 months (SD 11.9). Four patients (9%) were lost to follow-up. The mean Fecal Incontinence Severity Index postoperatively was only 2.35 (SD 5.7; range, 0-30). This resulted in 9 patients (20%) having a newly impaired continence status postoperatively. Continence impairment was mild in all these patients. The risk of developing a recurrence 1 year after surgery is 64.2% (95% CI, 49%-80%).

LIMITATIONS

This study was limited by its retrospective design and the small numbers with possible selection bias.

CONCLUSIONS

Results with the ligation of intersphincteric fistula tract procedure were not as good as hoped. The effect on fecal continence, however, was minimal. The procedure might be more suitable for low transsphincteric fistulas. See Video Abstract at http://links.lww.com/DCR/A992. LA LIGADURA DEL TRACTO DE LA FÍSTULA INTERESFINTÉRICA PARA UNA FÍSTULA TRANSESFINTÉRICA ALTA, PRODUCE RESULTADOS MODERADOS EN EL MEJOR DE LOS CASOS: ¿ESTÁ CAMBIANDO LA MAREA?: La ligadura del tracto de la fístula interesfintérica es un procedimiento quirúrgico bien aceptado y de uso frecuente para las fístulas perianales.

OBJETIVO

Confirmar los resultados de la ligadura del tracto de la fístula interesfintérica en un centro colorrectal especializado. DISEÑO:: Estudio de cohorte retrospectivo.

AJUSTE

Gran departamento de cirugía colorrectal y con centro de referencia terciaria para fístulas perianales.

PACIENTES

Pacientes consecutivos operados con ligadura del tracto de la fístula interesfintérica para una fístula perianal transesfintérica, entre 2012 y diciembre de 2018.

INTERVENCIONES

Ligadura del tracto de fístula interesfintérica.

PRINCIPALES MEDIDAS DE RESULTADO

Tasa de cicatrización, resultados secundarios: conversión a una fístula perianal interesfintérica, riesgo de recurrencia, complicaciones y estado de continencia postoperatoria.

RESULTADOS

Cuarenta y seis pacientes fueron tratados con una ligadura del tracto de la fístula interesfintérica. Todos los pacientes (100 por ciento) tenían imagenología en su preparación preoperatoria. Cuarenta pacientes (87 por ciento) tenían una fístula transesfintérica alta. La tasa de cicatrización primaria fue decepcionante en 17 de 46 pacientes (37 por ciento). El tiempo medio hasta el fracaso fue de 4.2 meses (rango intercuartil 3.5-6.5). De los fracasos, 16 se convirtieron en una fístula interesfintérica (55 por ciento de los fracasos y 35 por ciento de todos los pacientes). La duración media del seguimiento en pacientes sin recurrencia fue de 9.5 meses (desviación estándar de 11.9). Se perdieron durante el seguimiento a cuatro pacientes (9 por ciento). Después de la operación, el promedio del índice de severidad de incontinencia fecal fue de solo 2.35 (desviación estándar de 5.7, rango 0-30). Esto resultó en que 9 pacientes (20 por ciento) tuvieran una continencia deteriorada postoperatoria. El deterioro de la continencia fue leve en todos estos pacientes. El riesgo de desarrollar una recurrencia a un año después de la cirugía es del 64.2 por ciento (intervalo de confianza del 95 por ciento: 49-80 por ciento).

LIMITACIONES

Diseño retrospectivo, números pequeños con posible sesgo de selección.

CONCLUSIONES

Los resultados del procedimiento con la ligadura del tracto de fístula interesfintérica no fueron tan buenos como se esperaba. El efecto sobre la continencia fecal, sin embargo, fue mínimo. El procedimiento podría ser más adecuado para las fístulas transesfintéricas bajas. Vea el Resumen del video en http://links.lww.com/DCR/A992.

Photodynamic Therapy for the Treatment of Complex Anal Fistula

BACKGROUND AND OBJECTIVES

To validate and analyze the results of intralesional photodynamic therapy in the treatment of complex anal fistula.

STUDY DESIGN/MATERIALS AND METHODS

This prospective multicentric observational study enrolled patients treated for complex anal fistula who underwent intralesional photodynamic therapy (i-PDT). The included patients were treated from January 2016 to December 2018 with a minimum follow-up of 1 year to evaluate recurrence, continence and postoperative morbidity. Intralesional 5-aminolevulinic acid (ALA) gel (2%) was injected directly into the fistula. The internal and external orifices were closed. After an incubation period of 2 hours, the fistula was irradiated using an optical fiber connected to a red laser (Multidiode 630 PDT) operating at 1 W/cm for 3 minutes (180 J).

RESULTS

In total, 49 patients were included (61.2% male). The mean age was 48 years, and the mean duration of fistula was 13 months. Of the fistulas included, 75.5% were medium transphincteric, and 24.5% were high transphincteric. The median fistula length was 4 ± 1,14 cm (range: 3-5). A total of 41 patients (83.7%) had a previous history of fistula surgery. Preoperatively, some degree of anal incontinence was found in 5 patients (10.2%). No center reported any other procedure-related complications intraoperatively. Phototoxicity was found in one patient. In the first 48 hours after the procedure, fever was reported in 2 patients (4%). At the end of follow-up, total healing was observed in 32/49 patients (65.3%). No patient reported new incontinence postoperatively.

CONCLUSION

i-PDT could be considered a good choice in patients with complex anal fistulas to avoid surgery and its complications. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.

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.

Early Results of a Phase I Trial Using an Adipose-Derived Mesenchymal Stem Cell-Coated Fistula Plug for the Treatment of Transsphincteric Cryptoglandular Fistulas

BACKGROUND

Management of transsphincteric cryptoglandular fistulas remains a challenging problem and the optimal surgical approach remains elusive. Mesenchymal stem cells, increasingly being utilized for perianal Crohn's disease, offer a novel therapy to treat cryptoglandular fistulas.

OBJECTIVES

This study aimed to determine safety and feasibility of using an autologous mesenchymal stem cell-coated fistula plug in patients with transsphincteric cryptoglandular fistulas.

DESIGN

This study is a phase I clinical trial.

SETTING

This study was conducted at a tertiary academic medical center.

PATIENTS

Adult (>18 years) male and female patients with transsphincteric cryptoglandular fistulas were selected.

MAIN OUTCOMES MEASURES

The primary outcomes measured were the safety, feasibility, and efficacy of a mesenchymal stem cell-coated fistula plug in patients with transsphincteric fistulas.

RESULTS

Fifteen patients (8 women, mean age 39.8 years) with a single-tract transsphincteric fistula received a mesenchymal stem cell-loaded fistula plug and were followed for 6 months. Duration of disease at the time of study enrollment was a median of 3.0 years (range, 1-13 years) with a median of 3.5 (range, 1-20) prior surgical interventions. Adverse events included 1 plug extrusion, 1 abdominal wall seroma, 3 perianal abscesses requiring drainage, and 1 patient with perianal cellulitis. There were no serious adverse events. At 6 months, 3 patients had complete clinical healing, 8 had partial healing, and 4 patients showed no clinical improvement. Radiographic improvement was seen in 11 of 15 patients.

LIMITATIONS

This study was limited by the small cohort and short follow-up.

CONCLUSIONS

Autologous mesenchymal stem cell-coated fistula plug treatment of transsphincteric cryptoglandular fistulas was safe and feasible and resulted in complete or partial healing in a majority of patients. See Video Abstract at http://links.lww.com/DCR/A897.

[Quality indicators in the treatment of anal fistulas]

Anal fistulas are a common anorectal disease and are frequently associated with a perianal abscess. The etiology is based on a cryptoglandular infection in the intersphincteric space. Surgery remains the only definitive therapy. The primary goal of definitive fistula surgery is healing; however, success of fistula surgery is influenced by a variety of factors including the surgeon's experience, type of fistula, involvement of sphincter muscles, type of surgical procedure and patient-related factors. For the surgical treatment of a complex anal fistula, a variety of operative procedures have been described including fistulectomy with sphincterotomy, different flap procedures (e.g. mucosal flap and advancement flap) and finally so-called sphincter-preserving techniques, such as LIFT (ligation of intersphincteric fistula tract), VAAFT (video-assisted anal fistula treatment), the use of plugs of collagen or fibrin glue sealants as well as laser procedures or the clip. In the search for suitable quality indicators in anal fistula surgery there is a conflict between healing and preservation of continence. If potential quality indicators are identified the principles of anal fistula surgery must be adhered to and the appropriate selection of patients and procedures is of crucial importance to achieve high healing rates without compromising continence or inducing surgical revision due to abscesses or recurrence. Based on the available literature and guidelines, in the assessment of quality indicators considerable differences exist with respect to patient selection, etiology of anal fistulas and length of follow-up. Heterogeneity of treatment protocols lead to difficulties in a definitive assessment of which surgical treatment is the best option for complex anal fistulas.

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.

Pathogenesis and persistence of cryptoglandular anal fistula: a systematic review

Anal fistulas continue to be a problem for patients and surgeons alike despite scientific advances. While patient and anatomical characteristics are important to surgeons who are evaluating patients with anal fistulas, their development and persistence likely involves a multifaceted interaction of histological, microbiological, and molecular factors. Histological studies have shown that anal fistulas are variably epithelialized and are surrounded by dense collagen tissue with pockets of inflammatory cells. Yet, it remains unknown if or how histological differences impact fistula healing. The presence of a perianal abscess that contains gut flora commonly leads to the development of anal fistula. This implies a microbiological component, but bacteria are infrequently found in chronic fistulas. Recent work has shown an increased expression of proinflammatory cytokines and epithelial to mesenchymal cell transition in both cryptoglandular and Crohn's perianal fistulas. This suggests that molecular mechanisms may also play a role in both fistula development and persistence. The aim of this study was to examine the histological, microbiological, molecular, and host factors that contribute to the development and persistence of anal fistulas.