Clinical course of perianal fistulas in Crohn's disease

How to Approach the Difficult Perineum in Crohn's Disease

Crohn's disease (CD) is a chronic, inflammatory bowel disease with a wide range of presentations, including perianal disease. Presentation is variable, ranging from skin tags to complex fistulas, strictures, and nonhealing wounds. Symptoms of perianal CD can be devastating and may impact quality of life. Optimal management requires coordinated medical and surgical therapy. When possible, conservative treatment of perianal disease should be attempted. However, surgical treatment is often required, and some patients may ultimately require total proctocolectomy with permanent diversion due to the severity of disease. Even with close attention and treatment, disease can be recurrent, and complications of treatment are sometimes worse than the initial presentation. Novel treatments, including use of mesenchymal stem cells and autologous fat grafting, hold some promise, but are not yet widely available. Thorough knowledge of treatment options, careful patient selection, coordination between medical and surgical providers, and setting realistic expectations are important in the successful treatment of difficult perineal CD.

Disease Acceptance and Control from the Subjective Health Experience Model as Health Perception Predictors in Immune-Mediated Inflammatory Diseases

Background/Objectives: The multifactorial nature of immune-mediated inflammatory diseases (IMIDs) requires integrating pathophysiological understanding with subjective patient experiences. Patient-reported outcome measures (PROMs) are a useful tool for incorporating this in routine clinical practice. However, current PROMs do not fully encompass the complete subjective health experiences (SHE) of patients and are thus insufficient for guiding truly personalised care. The SHE model provides insights into SHE through the determinants of disease acceptance and perceived control. While validated across various demographics, its predictive power in IMIDs cohorts remains unexplored. This study aims to assess whether acceptance and perceived control in the SHE model predict health experiences in patients with IMID and how these immunological conditions compare. Methods: Questionnaires regarding health perception, acceptance, control, and subjective health experiences were distributed to 450 Dutch citizens. Descriptive statistics, reliability checks, and partial least squares structural equation modelling were used to examine relationships between variables. Results: Health perception strongly predicts SHE through acceptance and control. Across all conditions, the pathway moves from health perception to control, then to acceptance, and finally to SHE. However, the roles of acceptance and control differ by condition. In burdensome diseases like inflammatory bowel disease and rheumatoid arthritis, acceptance plays a greater role, while control has a stronger influence in conditions like psoriasis. Conclusions: This study supports the predictive validity of the SHE model for IMIDs, showing that disease acceptance and control affect health experiences differently across conditions. These insights improve the understanding of psychological factors in health experiences and call for tailored interventions for patients with IMID.

Total fistula volume predicts surgical outcomes in complex perianal fistulizing Crohn's disease following fistula-tract laser closure: a single-center retrospective study

BACKGROUNDS

This study aimed to identify risk factors influencing long-term treatment outcomes in patients with complex perianal fistulizing Crohn's disease (pfCD) following fistula-tract laser closure (FiLaC™).

METHODS

A retrospective analysis was conducted on data from patients with complex pfCD who underwent FiLaC™ from January 2019 to December 2020, including demographics, pharmacological regimens, and preoperative MRI assessments. Follow-up monitored fistula outcomes such as healing, remission, failure, and recurrence.

RESULTS

Among 49 patients followed for an average of 60.0 months, 31 (63.3%) achieved fistula healing, 3 (6.1%) showed improvement, 3 (6.1%) had non-healing, and 12 (24.5%) experienced recurrence. Significant differences were found between healed and unhealed groups in total fistula volume (TFV), number of fistula tracts, and perianal Crohn's disease activity index (PDAI) (P = 0.036, P = 0.020, and P = 0.041, respectively). Multivariate regression analysis indicated TFV as a significant predictor of healing outcomes (P = 0.013). ROC analysis confirmed its predictive value for fistula healing in complex pfCD, with an area under the curve (AUC) of 0.729 (P = 0.008). The optimal threshold for TFV was 4.81 cm3, with a sensitivity of 61.1% and a specificity of 83.9%. The AUC for recurrence rates was 0.883 (P < 0.001), with sensitivity and specificity at 83.3% and 83.8%, respectively, using the same threshold for TFV. The Kaplan-Meier survival curve highlighted the predictive potential of TFV for fistula recurrence (P < 0.0001).

CONCLUSIONS

TFV is an effective predictor of long-term outcomes in patients with complex pfCD following FiLaC™.

Navigating the complexities of perianal Crohn's disease: Diagnostic strategies, treatment approaches, and future perspectives

This article discusses the literature review article by Pacheco et al published in July 2024; the authors provided good reviews of perianal Crohn's disease (CD), and challenges faced by clinicians in the management. CD, characterized by its chronic and relapsing nature, is an idiopathic condition that can involve any segment of the gastrointestinal tract. Perianal disease impacts up to 40% of patients with CD, with perianal fistulas constituting up to 80% of perianal lesions. Perianal CD can be highly incapacitating and profoundly diminish the overall well-being of patients. The management focuses on controlling the perianal sepsis and treating luminal CD. Biologics are crucial to the treatment approach, and results have been encouraging. The surgery focuses on controlling the sepsis, with more definitive treatments being fistula surgery, fecal diversion, and proctectomy as the last resort. This manuscript briefly describes the burden of CD, the challenges posed by perianal CD, and the role of different treatment modalities from colorectal surgeon's perspective.

[Therapeutic challenges in difficult-to-treat, penetrating Crohn's disease - a multidisciplinary approach]

A rectovaginalis fistula a penetráló Crohn-betegség ritka szövődménye, jelenléte esetén a gyógyszeres kezelés és a sebészeti beavatkozás együttes alkalmazása javasolt. Habár perianalis sipollyal szövődött Crohn-betegség esetén a TNFα-blokkolók hatékonyak lehetnek, rectovaginalis fistula esetén kisebb hatékonyság mutatkozik, feltehetően anatómiai okok, valamint a gyulladás talaján megváltozott szövetekbe történő csökkent penetrációs készség miatt. Az újabb biologikumok és kis molekulájú szerek hatékonyságáról és biztonságosságáról penetráló Crohn-betegségben kevés adat áll rendelkezésünkre. Esetünk egy fiatal penetráló Crohn-beteg nőről szól, aki közepesen súlyos/súlyos betegségaktivitás és kiújuló rectovaginalis fistula miatt több vonalbeli biológiai kezelésben részesült. Ultimum refugiumként deviáló ileostoma képzése történt, illetve upadacitinib indult ötödik terápiás vonalként. 12 hetes indukciót követően a rectovaginalis sipoly teljes bezáródását, valamint a vastagbél teljes szakaszán komplett nyálkahártya-gyógyulást tapasztaltunk. Az ileostoma zárását aktivitásfokozódás vagy fistulakiújulás nem követte. A szelektív JAK1-gátló upadacitinib hatékonynak mutatkozott stomaképzést követően, nehezen kezelhető, közepesen súlyos-súlyos luminalis aktivitást mutató, recidív rectovaginalis fistulával szövődött Crohn-betegségben. Orv Hetil. 2024; 165(32): 1252–1257.

Long-term Outcomes of Perianal Fistulas in Pediatric Crohn's Disease

BACKGROUND

Approximately 30% of Crohn's disease-related perianal fistulas heal in the adult population with conventional medical and surgical interventions. This healing rate remains unknown in pediatric patients.

OBJECTIVE

This study aimed to determine the healing rate of pediatric perianal Crohn's fistulas and identify factors associated with healing.

DESIGN

Retrospective case series.

SETTING

A quaternary referral center.

PATIENTS

Patients aged <18 years with a Crohn's perianal fistula, seen between January 1, 1991, and August 1, 2021, were included in the study.

INTERVENTIONS

Multivariable logistic regression to identify factors independently associated with perianal fistula healing.

MAIN OUTCOME MEASURES

Healing of Crohn's perianal fistula at the date of last clinical encounter, defined as the clinical note reporting a healed fistula or normal perianal examination.

RESULTS

A total of 91 patients aged <18 years with a Crohn's disease-related perianal fistula were identified (59% female, 76% white). The mean (SD) age at Crohn's diagnosis was 12 (±4) years. The mean follow-up after Crohn's diagnosis was 10 (±7) years. Overall, 89% of patients had a perianal fistula, 2% had an anovaginal fistula, and 10% had an ileal pouch-associated fistula. Patients underwent a median (interquartile range) of 2 (1-5) operations. A seton was placed in 60% of patients, 47% underwent abscess drainage, and 44% underwent fistulotomy or fistulectomy. Fistula healing occurred in 71% of patients over a median of 1.3 (0.4-2.5) years. Seven patients (7%) underwent proctectomy, and 3 (3%) underwent ileal pouch excision. After multivariable adjustment, younger age at diagnosis of perianal fistula was associated with an increased likelihood of healing (OR 0.56 for each increased year; 95% CI, 0.34-0.92).

LIMITATIONS

Retrospective, single institution.

CONCLUSIONS

Over two-thirds of fistulas heal in pediatric Crohn's disease patients with conventional surgical and medical intervention. Younger age at fistula development is associated with an increased likelihood of healing. See Video Abstract at http://links.lww.com/DCR/C185 .

RESULTADOS A LARGO PLAZO DE LAS FSTULAS PERIANALES EN LA ENFERMEDAD DE CROHN EN PACIENTES PEDITRICOS

ANTECEDENTES:Aproximadamente el 30% de las fístulas perianales relacionadas con la enfermedad de Crohn se curan en la población adulta con intervenciones médicas y quirúrgicas convencionales. Esta tasa de curación sigue siendo desconocida en pacientes pediátricos.OBJETIVO:Determinar la tasa de curación de las fístulas de Crohn perianales en población pediátrica e identificar los factores asociados con la curación.DISEÑO:Serie de casos retrospectiva.ESCENARIO:Un centro de referencia cuaternario.PACIENTES:Pacientes menores de 18 años con fístula(s) perianal(es) por enfermedad de Crohn, atendidos entre el 1 de enero de 1991 y el 1 de agosto de 2021.INTERVENCIONES:Regresión logística multivariable para identificar factores asociados de forma independiente con la cicatrización de la fístula perianal.PRINCIPALES MEDIDAS DE RESULTADO:Curación de la fístula perianal de Crohn en la fecha del último encuentro clínico, definida como la nota clínica que informa una fístula curada o un examen perianal normal.RESULTADOS:Se identificó un total de 91 pacientes <18 años de edad con una fístula perianal relacionada con la enfermedad de Crohn (59% mujeres, 76% blancos). La edad media (DE) al diagnóstico de Crohn fue de 12 (±4) años. El seguimiento medio tras el diagnóstico de Crohn fue de 10 (±7) años. En general, el 89 % de los pacientes tenía fístula perianal, el 2 % tenía fístula anovaginal y el 10 % de los pacientes tenía fístula asociada a reservorio ileal. Los pacientes fueron sometidos a una mediana (RIC) de 2 (1-5) operaciones. En el 60% de los pacientes se colocó sedal, en el 47% se drenó el absceso y en el 44% se realizó fistulotomía o fistulectomía. La curación de la fístula se produjo en el 71% de los pacientes durante una mediana de 1,3 (0,4-2,5) años. Siete pacientes (7%) se sometieron a proctectomía y 3 (3%) se sometieron a escisión del reservorio ileal. Después del ajuste multivariable, la edad más joven en el momento del diagnóstico de la fístula perianal se asoció con una mayor probabilidad de curación (OR 0,56 por cada año de aumento, IC del 95%, 0,34-0,92).LIMITACIONES:Retrospectivo, institución única.CONCLUSIONES:Más de dos tercios de las fístulas se curan en pacientes pediátricos con enfermedad de Crohn con intervención médica y quirúrgica convencional. Una edad más joven en el momento del desarrollo de la fístula se asocia con una mayor probabilidad de curación. Consulte Video Resumen en http://links.lww.com/DCR/C185 . (Traducción--Dr. Felipe Bellolio ).

Endoscopic Evaluation and Management of Perianal Disease

Perianal Crohn's disease is associated with decreased quality of life, high morbidity, and high health care use. Treatment goals are to provide infection control, stop fistula drainage, and heal fistula tracts while preserving the anorectal sphincter. Treatment includes a combination of medical and surgical intervention, but new techniques are using interventional endoscopy to act as either a bridge to surgery or to decrease the need for surgical intervention. The decision on which approach to pursue requires knowledge of prior surgery, altered anatomy, prior fistula treatment, and imaging and endoscopic evaluation of fistula complexity, mucosal involvement, and associated stricture or abscess.

Diagnosis and Classification of Fistula from Inflammatory Bowel Disease and Inflammatory Bowel Disease-Related Surgery

Fistula in inflammatory bowel disease (IBD) is a well-known yet poorly understood phenotype. Pathophysiology is largely based on the activation of the epithelial-mesenchymal transition (EMT); however, interactions with the microbiome, genetics, mechanical stress and the presence of stricturing disease, and surgical complications play a role. Perianal penetrating disease represents a more severe phenotype in IBD. Pouch-associated fistula can arise as a result of an anastomotic leak, surgical complications, or Crohn's disease (CD) of the pouch. Classification is site-dependent, includes a range of severity, and informs management. It is important to determine associated symptoms and recognize the complex interplay of underlying etiologies to form the basis of appropriate care.

Higher infliximab and adalimumab trough levels are associated with fistula healing in patients with fistulising perianal Crohn’s disease

BACKGROUND

Tumor necrosis factor-alpha inhibitors, including infliximab and adalimumab, are effective medical treatments for perianal fistulising Crohn’s disease (CD), but not all patients achieve fistula healing.

AIM

To determine the correlation between perianal fistula healing and closure with infliximab and adalimumab trough levels.

METHODS

In this multicentre retrospective study conducted across four tertiary inflammatory bowel disease centres in Australia, we identified CD patients with perianal fistulae on maintenance infliximab or adalimumab who had a trough level within twelve weeks of clinical assessment. Data collected included demographics, serum infliximab and adalimumab trough levels (mg/L) within 12 wk before or after their most recent clinical assessment and concomitant medical or surgical therapy. The primary outcome was fistula healing, defined as cessation in fistula drainage. The secondary outcome was fistula closure, defined as healing and closure of all external fistula openings. Differences between patients who did or did not achieve fistula healing were compared using the chi-square test, t test or Mann-Whitney U test.

RESULTS

One hundred and fourteen patients (66 infliximab, 48 adalimumab) were included. Forty-eight (72.7%) patients on maintenance infliximab achieved fistula healing and 18 (27.3%) achieved fistula closure. Thirty-seven (77%) patients on maintenance adalimumab achieved fistula healing and 17 (35.4%) achieved fistula closure. Patients who achieved fistula healing had significantly higher infliximab and adalimumab trough levels than patients who did not [infliximab: 6.4 (3.8-9.5) vs 3.0 (0.3-6.2) mg/L, P = 0.003; adalimumab: 9.2 (6.5-12.0) vs 5.4 (2.5-8.3) mg/L, P = 0.004]. For patients on infliximab, fistula healing was associated with lower rates of detectable anti-infliximab antibodies and younger age. For patients on adalimumab, fistula healing was associated with higher rates of combination therapy with an immunomodulator. Serum trough levels for patients with and without fistula closure were not significantly different for infliximab [6.9 (4.3-10.2) vs 5.5 (2.5-8.3) mg/L, P = 0.105] or adalimumab [10.0 (6.6-12.0) vs 7.8 (4.2-10.0) mg/L, P = 0.083].

CONCLUSION

Higher maintenance infliximab and adalimumab trough levels are associated with perianal fistula healing in CD.

Surgical Management of Crohn's Disease

Treatment of Crohn's disease (CD) focuses on providing acceptable quality of life for the affected individual by optimizing medical therapy, endoscopic procedures, and surgical intervention. Biologics have changed the medical management of moderate to severe CD. However, despite their introduction, the need for surgical resection in CD has not drastically changed, with two-thirds of the patients still requiring an intestinal resection. Patient outcomes are optimized by focusing on preoperative management and intraoperative technical aspects to maximize bowel preservation. This article reviews some of the important principles of Crohn's surgery to help guide surgeons when approaching this challenging patient population.

Time to Revisit Disease Classification in Inflammatory Bowel Disease: Is the Current Classification of Inflammatory Bowel Disease Good Enough for Optimal Clinical Management?

Inflammatory bowel disease (IBD), historically subdivided into Crohn's disease and ulcerative colitis, is a very heterogeneous condition. While the tendency in medicine is to try to reduce complexity, IBD is a disease that cannot justify a one-size-fits-all principle. Our current clinical classification tools are suboptimal and need further refinement to capture, at least in part, the variety of phenotypes encountered in daily clinical practice. Although these revised classification tools alone will not be sufficient and should be complemented by more detailed molecular subclassifications, optimized clinical phenotypes can contribute to improved trial designs, future translational research approaches, and better treatment outcomes. In the current review, we discuss key clinical features important in IBD disease heterogeneity, tackle limitations of the current classification systems, propose some potential improvements, and raise priorities for future research in this domain.

Natural History of Perianal Crohn's Disease: Long-term Follow-up of a Population-Based Cohort

BACKGROUND AND AIMS

The natural history of perianal Crohn's disease (PCD) remains poorly described and is mainly based on retrospective studies from referral centers. The aim of this study was to assess the incidence, outcomes and predictors of the onset of PCD.

METHODS

All incident cases of patients diagnosed with possible CD were prospectively registered from 1994 to 1997 in Brittany, a limited area in France. At diagnosis, the clinical features of perianal disease were recorded. All patient charts were reviewed from the diagnosis to the last clinic visit in 2015.

RESULTS

Among the 272 out of 331 incident CD patients followed up, 51 (18.7%) patients had PCD at diagnosis. After a mean follow-up of 12.8 years, 93 (34%) patients developed PCD. The cumulative probabilities of perianal CD occurrence were 22%, 29%, and 32% after 1 year, 5 years, and 10 years, respectively. The cumulative probabilities of anal ulceration were 14%, and 19% after 1 year and 10 years, respectively. Extraintestinal manifestations were associated with the occurrence of anal ulceration. The cumulative probabilities of fistulizing PCD were 11%, 16%, and 19% after 1 year, 5 years, and 10 years, respectively. Extraintestinal manifestations, rectal involvement and anal ulceration were predictors of fistulizing PCD. The cumulative probability of developing anal stricture was 4% after 10 years.

CONCLUSIONS

PCD is frequently observed during CD, in approximately one-third of patients. These data underline the need for targeted therapeutic research on primary perianal lesions (proctitis, anal ulceration) to avoid the onset of fistulizing perianal disease.

Rectovaginal Fistula in Crohn's Disease: When and How to Operate?

Rectovaginal fistula (RVF) occurring during the course of Crohn's disease (CD) constitutes a therapeutic challenge and is characterized by a high rate of recurrence. To optimize the outcome of CD-related RVF repair, the best conditions for correct healing should be obtained. Remission of CD should be achieved with no active proctitis, the perianal CD activity should be minimized, and local septic complications should be controlled. The objective of surgical repair is to close the fistula tract with minimal recurrence and functional disturbance. Several therapeutic strategies exist and the approach should be tailored to the anatomy of the RVF and the quality of the local supporting tissues. Herein, we review the medical and surgical management of CD-related RVF.

Regenerative medicine for digestive fistulae therapy: Benefits, challenges and promises of stem/stromal cells and emergent perspectives via their extracellular vesicles

Despite current management strategies, digestive fistulae remain extremely debilitating complications associated with significant morbidity and mortality, generating a need to develop innovative therapies in these indications. A number of clinical trials and experimental studies have thus investigated the potential of stem/stromal cells (SCs) or SC-derived extracellular vesicles (EVs) administration for post-surgical and Crohn's-associated fistulae. This review summarizes the physiopathology and current standards-of-care for digestive fistulae, along with relevant evidence from animal and clinical studies regarding SC or EV treatment for post-surgical digestive fistulae. Additionally, existing preclinical models of fistulizing Crohn's disease and results of SC therapy trials in this indication will be presented. The optimal formulation and administration protocol of SC therapy products for gastrointestinal fistula treatment and the challenges for a widespread use of darvadstrocel (Alofisel) in clinical practice will be discussed. Finally, the potential advantages of EV therapy and the obstacles towards their clinical translation will be introduced.

Epidemiology and Natural History of Perianal Crohn's Disease: A Systematic Review and Meta-Analysis of Population-Based Cohorts

BACKGROUND AND AIMS

Perianal Crohn's disease (pCD) is a potentially severe phenotype of CD. We conducted a systematic review with meta-analysis to estimate cumulative incidence, risk factors, and outcomes of pCD in population-based cohort studies.

METHODS

Through a systematic literature review through March 1, 2021, we identified population-based inception cohort studies reporting cumulative incidence of perianal disease (primarily abscess and/or fistula) in patients with CD. We estimated the cumulative incidence of pCD at presentation and 1-, 5-, and 10-year follow-up, and risk factors for perianal disease and outcomes including risk of major (bowel resection, proctectomy, ostomy) and minor perianal (incision and drainage, seton placement, etc.) surgery.

RESULTS

In 12 population-based studies, prevalence of pCD was 18.7% (95% confidence interval [CI], 12.5%-27.0%) with 1-, 5-, and 10-year risk of perianal disease being 14.3% (95% CI, 7.9%-24.6%), 17.6% (95% CI, 11.3%-26.5%), and 18.9% (95% CI, 15.0%-23.4%), respectively. Approximately 11.5% of patients (95% CI, 6.7%-19.0%) had perianal disease at or before CD diagnosis. Colonic disease location and rectal involvement were associated with higher risk of pCD. Overall, 63.3% of patients (95% CI, 53.3-72.3) required minor perianal surgery and 6.4% of patients (95% CI, 1.8%-20.6%) required major abdominal surgery for pCD. Use of biologic therapy for pCD is common and has steadily increased throughout the years.

CONCLUSIONS

Approximately 1 in 5 patients with CD develops perianal disease within 10 years of CD diagnosis, including 11.5% who have perianal disease at presentation. Approximately two-thirds of patients require perianal surgery, with a smaller fraction requiring major abdominal surgery.

Minor Sphincter Sparing Surgery for Successful Closure of Perianal Fistulas in Patients with Crohn's Disease

The purpose of this study is to demonstrate that repetitive minor surgical procedures allow for a high rate of permanent closure of perianal fistulas in patients with Crohn’s disease (CD). Patients with perianal fistulizing CD (PFCD) who underwent perianal surgery at the University Hospital of Muenster between 2003 and 2018 were assessed for fistula characteristics and surgical procedures. We included 45 patients (m:f = 28:17) with a mean age of 27 years at first fistula appearance. Of these, 49% suffered from a complex fistula. An average of 4.2 (1–14) procedures were performed, abscess incisions and fistula seton drainages included. Draining setons were left in place for 5 (1–54) months, until fistula closure. Final surgical techniques were fistulotomy (31.1%), seton removal with sustained biological therapy (26.7%), Anal Fistula Plug (AFP) (17.8%), Over-The Scope-Clip proctology (OTSC) (11.1%), and mucosa advancement flap (4.4%). In 8.9% of cases, the seton was kept as permanent therapy. The time from first to last surgery was 18 (0–182) months and the median follow-up time after the last surgery was 90 (15–200) months. The recurrence rate was 15.5% after 45 (17–111) months. Recurrent fistulas healed after another 1.86 (1–2) surgical re-interventions. The final success rate was 80%. Despite biological treatment, PFCD management remains challenging. However, by repeating minor surgical interventions over a prolonged period of time, high permanent healing rates can be achieved.

Managing Complex Perianal Fistulizing Disease

Perianal disease is a particularly morbid phenotype of Crohn's disease, affecting up to one third of patients, with a significantly diminished quality of life. Conventional medical therapy and surgical interventions have limited efficacy. Medical treatment options achieve long-term durable remission in only a third of patients. Therefore, most patients undergo an operation, leaving them with a chronic seton or at risk of incontinence with multiple interventions. Mesenchymal stem cell therapy is an emerging therapy without risk of incontinence and improved efficacy as compared with conventional therapy. Laser therapy is another new intervention. Unfortunately, up to 40% of patients still require a stoma related to perianal fistulizing disease.

Approach to medical therapy in perianal Crohn's disease

Perianal Crohn's disease remains a challenging condition to treat and can have a substantial negative impact on quality of life. It often requires combined surgical and medical interventions. Anti-tumor necrosis factor (anti-TNF) therapy, including infliximab and adalimumab, remain preferred medical therapies for perianal Crohn's disease. Infliximab has been shown to be efficacious in improving fistula closure rates in randomized controlled trials. Clinicians can be faced with a number of questions relating to the optimal use of anti-TNF therapy in perianal Crohn's disease. Specific issues include evaluation for the presence of perianal sepsis, the treatment target of therapy, the ideal time to commence treatment, whether additional medical therapy should be used in conjunction with anti-TNF therapy, and the duration of treatment. This article will discuss key studies which can assist clinicians in addressing these matters when they are considering or have already commenced anti-TNF therapy for the treatment of perianal Crohn's disease. It will also discuss current evidence regarding the use of vedolizumab and ustekinumab in patients who are failing to achieve a response to anti-TNF therapy for perianal Crohn's disease. Lastly, new therapies such as local injection of mesenchymal stem cell therapy will be discussed.

Multidisciplinary management of perianal Crohn's disease

PURPOSE OF REVIEW

Multiple new medications with novel mechanisms of action are now available to treat Crohn's disease (CD). However, they have varying effectiveness in the management of perianal CD. Identifying the most appropriate therapy and optimizing it is essential to maximize effectiveness of therapy. Additionally, the management of perianal CD requires imaging of the perianal area to identify the fistula anatomy and local complications such as abscesses that require surgical drainage. Initial surgical assessment is key to drain abscesses and allow fistula healing with medical therapy.

RECENT FINDINGS

Although anti-tumor necrosis factor (TNFs) remain the most effective medications to treat perianal CD, real-world data suggests that ustekinumab may be a 2nd-line option in patients nonresponsive to an anti-TNF or having contraindications. Mesenchymal stem cells are an emerging therapeutic approach that is currently in Phase 3 trials in the United States and poised to play a major role in the treatment algorithm.

SUMMARY

The management of perianal CD requires a multidisciplinary approach with a combination of initial imaging and surgical assessment to adequately control local sepsis, optimization of biological therapy with adjunct antibiotics or immunomodulators, and close clinical follow-up with imaging to evaluate response to therapy and guide further surgical management options.

Prospective randomised controlled trial of adults with perianal fistulising Crohn's disease and optimised therapeutic infliximab levels: PROACTIVE trial study protocol

INTRODUCTION

Perianal fistulising Crohn's disease (pfCD) can be somewhat treatment refractory. Higher infliximab trough levels (TLIs) may improve fistula healing rates; however, it remains unclear whether escalating infliximab therapy to meet higher TLI targets using proactive, or routine, therapeutic drug monitoring (TDM) improves outcomes. This randomised controlled trial aimed to assess whether infliximab therapy targeting higher TLIs guided by proactive TDM improves outcomes compared with standard therapy.

METHODS AND ANALYSIS

Patients with active pfCD will be randomised 1:1 to either the proactive TDM arm or standard dosing arm and followed up for 54 weeks. Patients in the proactive TDM arm will have infliximab dosing optimised to target higher TLIs. The targets will be TLI ≥ 25 µg/mL at week 2, ≥ 20 µg/mL at week 6 and ≥ 10 µg/mL during maintenance therapy. The primary objective will be fistula healing at week 32. Secondary objectives will include fistula healing, fistula closure, radiological fistula healing, patient-reported outcomes and economic costs up to 54 weeks. Patients in the standard dosing arm will receive conventional infliximab dosing not guided by TLIs (5 mg/kg at weeks 0, 2 and 6, and 5 mg/kg 8 weekly thereafter). Patients aged 18-80 years with pfCD with single or multiple externally draining complex perianal fistulas who are relatively naïve to infliximab treatment will be included. Patients with diverting ileostomies or colostomies and pregnant or breast feeding will be excluded. Fifty-eight patients per arm will be required to detect a 25% difference in the primary outcome measure, with 138 patients needed to account for an estimated 6.1% primary non-response rate and 10% dropout rate.

ETHICS AND DISSEMINATION

Results will be presented in peer-reviewed journals and international conferences. Ethics approval has been granted by the South Western Sydney Local Health District Human Research Ethics Committee in Australia.

TRIAL REGISTRATION NUMBER

Australian New Zealand Clinical Trials Registry (ACTRN12621000023853); Pre-results.

Contribution of CD3+CD8- and CD3+CD8+ T Cells to TNF-α Overexpression in Crohn Disease-Associated Perianal Fistulas and Induction of Epithelial-Mesenchymal Transition in HT-29 Cells

BACKGROUND

Fistulas represent a frequent and severe complication in patients with Crohn disease (CD). Tumor necrosis factor-alpha (TNF-α), transforming growth factor-beta, and interleukin (IL)-13 are known to trigger epithelial-mesenchymal transition (EMT), promoting fistula formation. Here, we investigated the role of T-lymphocytes (T cells) in fistula pathogenesis.

METHODS

CD3+CD8-, CD3+CD8+, or CD45+CD3- cells from healthy volunteers, patients with CD, and patients with CD with perianal fistula were co-cultured with HT-29 cells. The EMT, cytokine production, and mRNA expression were analyzed. Perianal CD fistula specimens were immunohistochemically stained for cytokines and their receptors. The effect of cytokines on EMT induction was investigated using an EMT spheroid model.

RESULTS

Patients with CD with fistula revealed more CD3+CD8- and less CD3+CD8+ T cells in blood than healthy control patients and patients with CD without fistula. In perianal fistula specimens, CD4+ cells-and to a lesser extent CD8+ cells-were highly present around fistula tracts. When co-cultured with HT-29 cells, both cell subsets promoted EMT-related gene expression and TNF-α production in a time-dependent manner. The CD3+CD8- T cells from patients with CD with fistula also produced higher amounts of IL-13 than cells from healthy control patients or patients with CD without a fistula. We found that IL-22 and IL-22Rα1 were highly expressed in perianal CD fistula specimens and that IL-22 cotreatment potentiated TNF-α-induced EMT in HT-29 spheroids.

CONCLUSIONS

Our data indicate that both CD3+CD8- and CD3+CD8+ T cells play an important role in the pathogenesis of perianal CD fistulas by the secretion of TNF-α. Our data support clinical evidence indicating that anti-TNF-α therapy is effective in fistula treatment and identify IL-13 and IL-22 as possible novel therapeutic targets for fistula therapy.

Treatment Strategy for Perianal Fistulas in Crohn Disease Patients: The Surgeon's Point of View

Perianal fistula is a frequent complication and one of the subclassifications of Crohn disease (CD). It is the most commonly observed symptomatic condition by colorectal surgeons. Accurately classifying a perianal fistula is the initial step in its management in CD patients. Surgical management is selected based on the type of perianal fistula and the presence of rectal inflammation; it includes fistulotomy, fistulectomy, seton procedure, fistula plug insertion, video-assisted ablation of the fistulous tract, stem cell therapy, and proctectomy with stoma creation. Perianal fistulas are also managed medically, such as antibiotics, immunomodulators, and biologics including anti-tumor necrosis factor-alpha agents. The current standard treatment of choice for perianal fistula in CD patients is the multidisciplinary approach combining surgical and medical management; however, the rate of long-term remission is low and is reported to be 50% at most. Therefore, the optimum management strategy for perianal fistulas associated with CD remains controversial. Currently, the goal of management for CD-related perianal fistulas are controlling symptoms and maintaining long-term anal function without proctectomy, while monitoring progression to anorectal carcinoma. This review evaluates perianal fistula in CD patients and determines the optimal surgical management strategy based on recent evidence.

Hot topics in global perianal fistula research: A scopus-based bibliometric analysis

BACKGROUND

The number of citations a scientific paper has received indicates its impact within any medical field. We performed a bibliometric analysis to highlight the key topics of the most frequently cited 100 articles on perianal fistula to determine the advances in this field.

METHODS

The Scopus database was searched from 1960 to 2018 using the search terms "perianal fistula" or "anal fistula" or "fistula in ano" or "anal fistulae" or "anorectal fistulae" including full articles. The topic, year of publication, publishing journal, country of origin, institution, and department of the first author were analyzed.

RESULTS

The median number of citations for the top 100 of 3431 eligible papers, ranked in order of the number of citations, was 100 (range: 65-811), and the number of citations per year was 7.5 (range: 3.8-40.1). The most-cited paper (by Parks et al in 1976; 811citations) focused on the classification of perianal fistula. The institution with the highest number of publications was St Mark's Hospital, London, UK. The most-studied topic was surgical management (n = 47). The country and the decade with the greatest number of publications in this field were the USA (n = 34) and the 2000s (n = 50), respectively.

CONCLUSION

The 100 most frequently cited manuscripts showed that surgical management had the greatest impact on the study of perianal fistula. This citation analysis provides a reference of what could be considered the most classic papers on perianal fistula, and may serve as a reference for researchers and clinicians as to what constitutes a citable paper in this field.

Higher anti-tumor necrosis factor levels are associated with perianal fistula healing and fistula closure in Crohn's disease

OBJECTIVE

Limited data are available regarding the relationship between anti-tumor necrosis factor (TNF) drug/antibody levels and perianal fistula outcomes in Crohn's disease. The aims of this study were to assess the relationship between maintenance anti-TNF levels and perianal fistula outcomes.

METHODS

This was a retrospective cross-sectional study of patients receiving maintenance adalimumab or infliximab therapy (minimum 24 weeks) for the treatment of Crohn's disease with associated perianal fistulas, who had anti-TNF drug/antibody levels (trough for infliximab) measured within 4 weeks of clinical assessment. The primary outcome was the association of anti-TNF levels with perianal fistula healing defined as the absence of drainage. The secondary outcome was the association of anti-TNF levels with complete perianal fistula closure.

RESULTS

A total of 64 patients (adalimumab, n = 35; infliximab, n = 29) were included. Patients with fistula healing had higher levels of anti-TNF vs. those without fistula healing (adalimumab: 12.6 vs. 2.7 μg/mL, P < 0.01; infliximab: 8.1 vs. 3.2 μg/mL, P < 0.01). Patients with fistula closure also had significantly higher anti-TNF levels vs. those without fistula closure (adalimumab: 14.8 vs. 5.7 μg/mL, P < 0.01; infliximab: 8.2 vs. 3.2 μg/mL, P < 0.01). For adalimumab, receiver operator characteristic analysis identified an optimum level of >6.8 μg/mL and >9.8 μg/mL for fistula healing and closure, respectively. For infliximab, receiver operator characteristic analysis identified an optimum trough level of >7.1 μg/mL for both fistula healing and closure.

CONCLUSION

Higher maintenance anti-TNF levels are associated with perianal fistula healing and closure in Crohn's disease.

Strategies to Optimize Anti-tumor Necrosis Factor Therapy for Perianal Fistulizing Crohn's Disease: A Systematic Review

Tumor necrosis factor (TNF) antagonists are considered the cornerstone therapy for fistulizing perianal Crohn's disease (PCD), yet a substantial proportion of patients fail to achieve healing. Therefore, we reviewed the evidence for strategies to enhance the efficacy of TNF antagonists for PCD. A systematic search of electronic databases through July 2018 was performed to identify studies that assessed the effectiveness of TNF antagonists combined with another medical or surgical intervention for PCD; or assessed the association between anti-TNF serum concentrations and fistula healing. Twelve studies compared anti-TNF therapy alone versus a combined approach: four with surgery, three with antibiotics, and five with immunomodulators. Only two studies, both with antibiotics, were rated high quality. The addition of antibiotics to anti-TNF therapy resulted in significantly higher rates of fistula response and healing in one study, and a trend toward reduction in fistula drainage in the other. Three of four studies found higher rates of fistula healing when surgery was combined with TNF antagonists. In contrast, one of five studies found a trend toward higher rates of fistula healing in patients treated concomitantly with immunomodulators. Five observational studies assessed the association between anti-TNF concentration and fistula healing. Higher infliximab serum concentrations were consistently associated with fistula healing. In conclusion, few high-quality studies assessing strategies to optimize anti-TNF therapy for PCD exist. Although antibiotics, possibly surgery, and higher serum infliximab concentrations appear to improve fistula healing, future prospective studies are needed to determine the optimal treatment strategy.

Anorectal Crohn's Disease

Medical treatment remains the mainstay of perianal disease management for CD; however, aggressive surgical management should be considered for severe or recurrent disease. In all cases of perianal CD, medical and surgical treatments should be used in tandem by a multidisciplinary team. Significant development has been made in the treatment of Crohn's-related fistulas, particularly minimally invasive options with recent clinical trials showing success with mesenchymal stem cell applications. Inevitably, some patients with severe refractory disease may require fecal diversion or proctectomy. When considering reversal of a diverting or end ileostomy, cessation of proctitis is the most important factor.

A 10-Year Follow-up Study of the Natural History of Perianal Crohn's Disease in a Danish Population-Based Inception Cohort

BACKGROUND

Perianal complications in patients with Crohn's disease are common and have a negative impact on the patients' quality of life. Data about the long-term disease course of perianal Crohn's disease in the era of biological treatment are limited. In this population-based cohort study, we sought to investigate the occurrence, clinical risk factors, and disease course of perianal disease.

METHODS

A total of 213 Crohn's disease patients were included in a prospective population-based inception cohort. Data were retrieved from medical records and national health administrative databases. Perianal disease was defined as a perianal fistula and/or abscess. Associations between outcomes and covariates were analyzed by Cox regression analysis.

RESULTS

A total of 48 (22.5%) patients developed perianal disease after 10 years. Colonic disease location (hazard ratio [HR], 1.99; 95% confidence interval [CI], 1.01-3.92) and penetrating behavior (HR, 5.65; 95% CI, 2.65-12.03) were associated with the development of perianal disease. The cumulative risk of undergoing abdominal surgery was 51% after 10 years. Patients with perianal disease had a higher rate of resection (HR, 3.92; 95% CI, 1.86-8.67) and hospitalization (HR, 1.01; 95% CI, 1.00-1.01). There was no significant difference in the rate of sick leave, unemployment, or disability pension between patients with and without perianal disease.

CONCLUSIONS

Patients with perianal disease carry a higher risk of surgery and hospitalization, and this suggests a more severe disease course and poorer prognosis among these patients, even in the era of biological treatment. These findings underline the importance of optimizing treatment strategies for patients with perianal disease.

Cx601 (darvadstrocel) for the treatment of perianal fistulizing Crohn's disease

Introduction: Given the well-documented difficulty to treat perianal fistulizing Crohn's disease (pCD), with 40% of patients experiencing recurrence even after reiterative surgery and advanced medical therapy, research in this field has focused on the role of mesenchymal stem cells (MSC). Areas covered: The aim of this article is to furnish an overview of the pathogenetic mechanisms, clinical applications and evidences for the use of MSC for pCD with particular focus on adipose-derived allogenic MSC including darvadstrocel. Expert Opinion: The effect of MSC on fistula healing is probably mediated by their anti-inflammatory properties more than by their ability to engraft and trans-differentiate in the healthy tissue. A holistic treatment of pCD, addressing different pathophysiological factors, may represent the key for an improvement in the healing rate. In this setting, MSC might play a role as 'augmentation' therapy in combination with more conventional treatments. Whether MSC have benefit in non-complex fistula in biological naïve patients, in complex fistula with many tracts and/or in rectovaginal fistulas, are unexplored fields that need further investigation. A central registry of pCD patients undergoing treatment with MSC should be created in order to elucidate the efficacy, safety and costs of stem cells treatment on long term follow up.

Recent advances in the management of perianal fistulizing Crohn's disease: lessons for the clinic

Managing fistulizing perianal disease is among the most challenging aspects of treating patients with Crohn's disease. Perianal fistulas are indicative of poor long-term prognosis. They are commonly associated with significant morbidities and can have detrimental effects on quality of life. While durable fistula closure is ideal, it is uncommon. In optimal circumstances, reported long-term fistula healing rates are only slightly higher than 50% and recurrence is common. Achieving these results requires a combined medical and surgical approach, highlighting the importance of a highly skilled and collaborative multidisciplinary team. In recent years, advances in imaging, biologic therapies and surgical techniques have lent to growing enthusiasm amongst treatment teams, however the most advantageous approach is yet to be determined. Areas covered: Here we review current management approaches, incorporating recent guidelines and novel therapies. Additionally, we discuss recently published and ongoing studies that will likely impact practice in the coming years. Expert opinion: Investing in concerted collaborative multi-institutional efforts will be necessary to better define optimal timing and dosing of medical therapy, as well as to identify ideal timing and approach of surgical interventions. Standardizing outcome measures can facilitate these efforts. Clearly, experienced multidisciplinary teams will be paramount in this process.

Higher anti-TNF serum levels are associated with perianal fistula closure in Crohn's disease patients

Objectives: Anti-TNF agents are effective to treat perianal Crohn's disease (CD). Evidence suggests that Crohn's disease patients with perianal fistulas need higher infliximab (IFX) serum concentrations compared to patients without perianal CD to achieve complete disease control. Our aim was to compare anti-TNF serum concentrations between patients with actively draining and closed perianal fistulas. Methods: A retrospective survey was performed in CD patients with perianal disease treated with IFX or adalimumab (ADL). Fistula closure was defined as absence of active drainage at gentle finger compression and/or fistula healing on magnetic resonance imaging. Results: We identified 66 CD patients with a history of perianal fistulas treated with IFX (n = 47) and ADL (n = 19). Median IFX serum trough concentrations ([interquartile range]) were higher in patients with closed fistulas (n = 32) compared to patients with actively draining fistulas (n = 15): 6.0 µg/ml [5.4-6.9] versus 2.3 µg/ml [1.1-4.0], respectively (p < .001)). A similar difference was seen in patients treated with ADL: median serum concentrations were 7.4 µg/ml [6.5-10.8] in 13 patients with closed fistulas versus 4.8 µg/ml [1.7-6.2] in 6 patients with producing fistulas (p = .003). Serum concentrations of ≥5.0 µg/ml for IFX (area under the curve of 0.92; 95% CI: 0.82-1.00)) and 5.9 µg/ml for ADL (area under the curve of 0.89; 95% CI 0.71-1.00) were associated with fistula closure. Conclusion: Cut-off serum concentrations ≥5.0 µg/ml for IFX and ≥5.9 µg/ml for ADL were associated with perianal fistula closure. Hence, patients with producing perianal fistulas may benefit from anti-TNF dose intensification to achieve fistula closure.

Evaluating the effectiveness of infliximab on perianal fistulizing Crohn's disease by magnetic resonance imaging

Background and aim

Data on the radiologic evaluation of perianal fistulizing Crohn’s disease (PFCD) naïve to anti-tumor necrosis factor therapy are scarce, especially in Asian populations. We assessed the effectiveness of infliximab (IFX) on PFCD and explored predictors of ‘deep remission’ based on clinical and radiologic assessments.

Methods

Patients with Crohn’s disease and active anal fistulas attending our care center for IFX therapy were prospectively enrolled. Each patient underwent clinical examination according to the Fistula Drainage Assessment Index, endoscopy for assessment of Crohn’s Disease Activity Index (CDAI) and Perianal Crohn’s Disease Activity Index (PCDAI), magnetic resonance imaging (MRI) to determine Van Assche score and Ng score, and laboratory tests up to 2 weeks prior to the start of and up to 2 weeks after the sixth IFX therapy (Week 32).

Results

Among 38 patients treated with IFX, 52.6% achieved clinical remission based on the Fistula Drainage Assessment Index and 42.1% achieved deep remission based on Ng score. Van Assche score (from 14.5 ± 4.26 to 7.36 ± 7.53), CDAI (from 170 ± 92 to 71 ± 69) and PCDAI (from 7.45 ± 2.65 to 2.44 ± 3.20) decreased significantly after six IFX treatments. The only predictor of deep remission was simple fistula (P = 0.004, odds ratio = 3.802, 95% confidence interval: 1.541–9.383).

Conclusions

IFX has been shown to have appreciable effectiveness in Chinese patients with PFCD. MRI is the gold standard for evaluating PFCD, but Van Assche score has some limitations.

Mesenchymal stromal cells in the treatment of perianal fistulas in Crohn's disease

Significant unmet needs remain in patients with Crohn's disease and perianal fistulas. Mesenchymal stromal cells have potent immunomodulatory actions. The Phase II studies reported efficacy of local injection of mesenchymal stromal cells to achieve closure of fistulas. A Phase III trial demonstrated that in patients with Crohn's disease and refractory complex perianal fistulas, a single injection of 120 × 106 cells was superior to local injection of placebo associated with the same surgical procedure, in obtaining closure of the fistula tracts together with absence of abscesses >2 cm, 24 weeks after the injection, a stringent combined primary end point. The benefit over placebo was sustained 52 weeks after the single injection. The therapy is safe with adverse events limited to local pain.

A novel model of acellular dermal matrix plug for anal fistula treatment. Report of a case and surgical consideration based on first utility in Poland

Anal fistula (AF) is a pathological connection between anus and skin in its surroundings. The main reason for the formation of anal fistula is a bacterial infection of the glands within the anal crypts. One of the modern techniques for the treatment of fistulas that do not interfere with the sphincters consists in implantation of a plug made from collagen material. We are presenting the first Polish experience with a new model of biomaterial plug for the treatment of anal fistula. We also point out key elements of the procedure (both preoperative and intraoperative) associated with this method. In the authors' opinion, the method is simple, safe and reproducible. Innovative shape of the plug minimizes the risk of its migration and rotation. It also perfectly blends with and adapts to the course and shape of the fistula canal, allowing it to become incorporated and overgrown with tissue in the fistula canal. The relatively short operation time, minor postoperative pain and faster convalescence are with no doubt additional advantages of the method. Long-term observation involving more patients is essential for evaluation of the efficacy of the treatment of fistulas with the new type of plug.

Comparison of Stromal Vascular Fraction with or Without a Novel Bioscaffold to Fibrin Glue in a Porcine Model of Mechanically Induced Anorectal Fistula

BACKGROUND

Anorectal fistulas (ARFs) are a common, devastating, event in the life of a patient with Crohn's disease. ARFs occur in up to 50% of patients with Crohn's disease. Treatment begins with surgical drainage of the initial abscess, followed by antibiotic therapy, then anti-inflammatory medications. If medical therapy fails to close the fistula tract, surgical intervention is often pursued. Surgery incurs risk of incontinence because of sphincter injury. Increasingly, the role of cell-based therapy is being investigated in ARFs. We evaluated the role a bioabsorbable scaffold plays in delivering cell-based therapy using a porcine model of AFR.

METHODS

ARFs were mechanically created and matured by setons. After 28 days, setons were removed; periaortic fat was harvested and processed for stromal vascular fraction (SVF). The cells were labeled with a membrane stain for later identification, then injected into the fistula or implanted through scaffold. Fistulas not treated with cells were injected with fibrin glue. Animals were monitored visually for healing at weeks 2 and 4, then euthanized to evaluate fistulas for histologic healing.

RESULTS

All fistulas (6/6) treated with SVF + scaffolds healed by week 2, compared with only 4/6 with just SVF and 0/5 treated with fibrin glue. Scaffolds retained SVF within the fistula tract more readily than injection method and SVF+scaffold treatment accelerated the healing process. Robust neovascularization was also seen in fistulas treated with SVF+scaffold. No adverse events occurred.

CONCLUSIONS

Scaffold technology may improve cell-based therapy healing rates for Crohn's ARFs. This advance should be investigated by human trials.

Perianal fistulizing Crohn's disease: pathogenesis, diagnosis and therapy

Perianal fistulizing Crohn's disease has a major negative effect on patient quality of life and is a predictor of poor long-term outcomes. Factors involved in the pathogenesis of perianal fistulizing Crohn's disease include an increased production of transforming growth factor β, TNF and IL-13 in the inflammatory infiltrate that induce epithelial-to-mesenchymal transition and upregulation of matrix metalloproteinases, leading to tissue remodelling and fistula formation. Care of patients with perianal Crohn's disease requires a multidisciplinary approach. A complete assessment of fistula characteristics is the basis for optimal management and must include the clinical evaluation of fistula openings, endoscopic assessment of the presence of proctitis, and MRI to determine the anatomy of fistula tracts and presence of abscesses. Local injection of mesenchymal stem cells can induce remission in patients not responding to medical therapies, or to avoid the exposure to systemic immunosuppression in patients naive to biologics in the absence of active luminal disease. Surgery is still required in a high proportion of patients and should not be delayed when criteria for drug failure is met. In this Review, we provide an up-to-date overview on the pathogenesis and diagnosis of fistulizing Crohn's disease, as well as therapeutic strategies.

Interdisciplinary Management of Perianal Crohn's Disease

Perianal disease is a common manifestation of Crohn disease (CD) that results in significant morbidity and decreased quality of life. Despite several medical and surgical options, complex perianal CD remains difficult to treat. Before the advent of biologic therapy, antibiotics were the mainstay of medical treatment. Infliximab remains the most well-studied medical therapy for perianal disease. Surgical interventions are limited by the risk of nonhealing wounds and potential incontinence. When treatment options fail, fecal diversion or proctectomy may be necessary. Stem cell therapies may offer improved results and seem to be safe, but are not yet widely used.

Fistulizing Crohn's Disease

Fistulas still represent one of the most important complications in patients with Crohn’s disease (CD). At least one third of CD patients suffer from fistulas during their disease course and amongst them longstanding remission of complex fistulas occurs only in about one third. So far, fistula pathogenesis is only partially understood. From a histopathological view, a fistula is a tube covered by flat epithelial cells. Current research suggests that the driving force for fistula development is epithelial-to-mesenchymal transition (EMT). Around the fistula, high levels of tumor necrosis factor (TNF), IL-13, and TGFβ can be detected and recent studies indicated an involvement of the intestinal microbiota. Fistula diagnosis requires clinical and surgical assessment, radiologic investigations, e.g., magnet resonance imaging and endoscopy. Routine medical treatment of fistulas includes antibiotics, immunosuppressives, and anti-TNF antibodies. There is no well-established role for calcineurin inhibitors in fistula treatment, corticosteroids appear to be even contra-productive. A promising novel approach might be the application of adipose tissue-derived or bone marrow-derived mesenchymal stem cells that have been studied recently. Due to insufficient efficacy of medical treatment and recurrence of fistulas, surgical interventions are frequently necessary. Further research is needed to better understand fistula pathogenesis aiming to develop novel treatment option for our patients.

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.

MR Imaging of Perianal Crohn Disease

Pelvic magnetic resonance (MR) imaging is currently the standard for imaging perianal Crohn disease. Perianal fistulas are a leading cause of patient morbidity because closure often requires multimodality treatments over a prolonged period of time. This review summarizes clinically relevant anal sphincter anatomy, imaging methods, classification systems, and treatment objectives. In addition, the MR appearance of healing perianal fistulas and fistula complications is described. Difficult imaging tasks including the assessment of rectovaginal fistulas and ileoanal anastomoses are highlighted, along with illustrative cases. Emerging innovative treatments for perianal Crohn disease are now available and have the promise to better control sepsis and maintain fecal continence. Different treatment modalities are selected based on fistula anatomy, patient factors, and management goals (closure versus sepsis control). Radiologists can help maximize patient care by being familiar with MR imaging features of perianal Crohn disease and knowledgeable about what features may influence therapy decisions. ^© RSNA, 2017 Online supplemental material is available for this article.

Higher infliximab trough levels are associated with perianal fistula healing in patients with Crohn's disease

BACKGROUND

Infliximab has been found to be efficacious in the treatment of fistulas in the setting of Crohn's disease, even though some patients do not benefit from therapy.

AIM

To assess the correlation between perianal fistula healing and trough levels of infliximab.

METHODS

In this cross-sectional study, we identified patients with Crohn's disease who had perianal fistulas and were treated with infliximab for at least 24 weeks. We excluded patients who underwent a faecal diversion procedure or proctectomy. Predictive variables included demographics, disease phenotype, disease activity, infliximab levels, anti-infliximab antibodies. The primary outcome was fistula healing defined as the absence of drainage. The secondary outcome was complete fistula closure and mucosal healing.

RESULTS

117 patients were included. Patients with fistula healing had significantly higher median serum infliximab levels when compared to those with active fistulas [15.8 vs. 4.4 μg/mL, respectively (P < 0.0001)]. There was an incremental gain in fistula healing with higher infliximab levels. The AUC for the association between fistula healing and infliximab levels was 0.82 (P < 0.0001), while the AUC for the association of infliximab levels and fistula closure was 0.69 (P = 0.014). Patients with anti-infliximab antibodies had a lower chance of achieving fistula healing (OR: 0.04 [95%CI: 0.005-0.3], P < 0.001).

CONCLUSIONS

There is a significant association between serum infliximab levels and rates of fistula healing. Achieving infliximab levels ≥10.1 mcg/mL in patients with Crohn's disease and perianal fistulas may improve outcomes as part of a treat-to-target strategy.

Crohn's disease for the general physician: management

Crohn's disease presents to general physicians in a variety of ways. The previous article outlined clinical features and initial investigations, and this article covers management of Crohn's disease, including monitoring and drug toxicity.

Evolving Concepts in Phases I and II Drug Development for Crohn's Disease

The highest attrition rates during drug development programmes occur at the proof of concept stage. Given the large number of molecules under development for Crohn's disease, a need exists to improve the efficiency of early drug development by fast-tracking promising agents and terminating ineffective ones. Multiple opportunities are available to achieve these goals, including the use of more responsive outcome measures, and the incorporation of sophisticated pharmacokinetic modelling and/or highly specific pharmacodynamic markers into exposure-based dosing regimens and novel trial designs. In this article we review these strategies and propose an integrated paradigm of early drug development in Crohn's disease.

Results of the Fifth Scientific Workshop of the ECCO [II]: Clinical Aspects of Perianal Fistulising Crohn's Disease-the Unmet Needs

BACKGROUND AND AIMS

Perianal fistulas affect up to one-third of Crohn's patients during the course of their disease. Despite the considerable disease burden, current treatment options remain unsatisfactory. The Fifth Scientific Workshop [SWS5] of the European Crohn's and Colitis Organisation [ECCO] focused on the pathophysiology and clinical impact of fistulas in the disease course of patients with Crohn's disease [CD].

METHODS

The ECCO SWS5 Working Group on clinical aspects of perianal fistulising Crohn's disease [pCD] consisted of 13 participants, gastroenterologists, colorectal surgeons, and a histopathologist, with expertise in the field of inflammatory bowel diseases. A systematic review of literature was performed.

RESULTS

Four main areas of interest were identified: natural history of pCD, morphological description of fistula tracts, outcome measures [including clinical and patient-reported outcome measures, as well as magnetic resonance imaging] and randomised controlled trials on pCD.

CONCLUSIONS

The treatment of perianal fistulising Crohn's disease remains a multidisciplinary challenge. To optimise management, a reliable classification and proper trial endpoints are needed. This could lead to standardised diagnosis, treatment, and follow-up of Crohn's perianal fistulas and the execution of well-designed trials that provide clear answers. The prevalence and the natural history of pCD need further evaluation.

Perianal Fistula With and Without Abscess: Assessment of Fistula Activity Using Diffusion-Weighted Magnetic Resonance Imaging

Background:

Magnetic resonance imaging (MRI) is highly accurate for the depiction of both the primary tract of fistula and abscesses, in patients with perianal disease. In addition, MRI can be used to evaluate the activity of fistulas, which is a significant factor for determining the therapeutic strategy.

Objectives:

This study aimed to determine the usefulness of diffusion-weighted (DW) MRI for assessing activity and visibility of perianal fistula.

Patients and Methods:

Fifty-three patients with 56 perianal fistulas were included in the current retrospective study. The T2-weighted imaging (T2WI) and DWMRI were performed and apparent diffusion coefficient (ADC) values of fistulas were measured. Fistulas were classified into two groups: only perianal fistulas and fistulas accompanied by abscess. Fistulas were also classified into two groups, based on clinical findings: positive inflammatory activity (PIA) and negative inflammatory activity (NIA).

Results:

Mean ADC value (mm²/s) of PIA group was significantly lower than that of NIA group, regarding lesions in patients with abscess-associated fistulas (1.371 × 10^-3 ± 0.168 × 10^-3 vs. 1.586 × 10^-3 ± 0.136 × 10^-3; P = 0.036). No statistically significant difference was found in mean ADC values between PIA and NIA groups, in patients with only perianal fistulas (P = 0.507). Perianal fistula visibility was greater with combined evaluation of T2WI and DWMRI than with T2WI, for two reviewers (P = 0.046 and P = 0.014).

Conclusion:

The DWMRI is a useful technique for evaluating activity of fistulas with abscess. Perianal fistula visibility is greater with combined T2WI and DWMRI than T2WI alone.

Disappointing durable remission rates in complex Crohn's disease fistula

BACKGROUND

Despite potent drugs and surgical techniques, the treatment of perianal fistulizing Crohn's disease (CD) remains challenging. We assessed treatment strategies for perianal fistulizing CD and their effect on remission, response, and relapse.

METHODS

Patients with perianal fistulizing CD visiting the Erasmus MC between January 1, 1980 and January 1, 2000 were identified. Demographics, fistula characteristics, and received treatments aimed at the outcome of these strategies were noted.

RESULTS

In total, 232 patients were identified (98 male; 42.2%). Median follow-up was 10.0 years (range, 0.5-37.5 yr). Complex fistulas were present in 78.0%. Medical treatment (antibiotics, steroids, immunosuppressants, and anti-tumor necrosis factor) commenced in 79.7% of the patients and in 53.2%, surgery (colectomy, fistulectomy, stoma, and rectum amputation) was performed. Simple fistulas healed more often than complex fistulas (88.2% versus 64.6%; P < 0.001). Rectum involvement was not associated with a lower remission rate, and anti-tumor necrosis factor therapy did not increase complete fistula healing rates in simple and complex fistula. Initially, healed fistulas recurred in 26.7% in case of simple fistulas and in 41.9% in case of complex fistulas (P = 0.051). Only 37.0% of the complex fistulas were in remission at the end of follow-up compared with 66.7% of the simple fistulas (P < 0.001).

CONCLUSIONS

Only the minority of CD complex perianal fistulas were in remission after conventional treatment strategies after a median follow-up of 10 years. Simple fistulas were more likely to heal than complex fistulas, and less of these healed fistulas relapsed. However, more than 3 quarters of the patients had complex perianal fistulas.

Multidisciplinary and evidence-based management of fistulizing perianal Crohn's disease

Perianal symptoms are common in patients with Crohn's disease and cause considerable morbidity. The etiology of these symptoms include skin tags, ulcers, fissures, abscesses, fistulas or stenoses. Fistula is the most common perianal manifestation. Multiple treatment options exist although very few are evidence-based. The phases of treatment include: drainage of infection, assessment of Crohn's disease status and fistula tracts, medical therapy, and selective operative management. The impact of biological therapy on perianal Crohn's disease is uncertain given that outcomes are conflicting. Operative treatment to eradicate the fistula tract can be attempted once infection has resolved and Crohn's disease activity is controlled. The operative approach should be tailored according to the anatomy of the fistula tract. Definitive treatment is challenging with medical and operative treatment rarely leading to true healing with frequent complications and recurrence. Treatment success must be weighed against the risk of complications, specially anal sphincter injury. A full understanding of the etiology and all potential therapeutic options is critical for success. Multidisciplinary management of fistulizing perianal Crohn's disease is crucial to improve outcomes.

Anorectal complications and function in patients suffering from inflammatory bowel disease: a series of patients with long-term follow-up

AIM

The aim of this study is to describe the long-term course of anorectal complains and function in a single centre cohort patients suffering from inflammatory bowel disease (IBD) with perianal lesions.

METHODS

Between 1993 and 2000, 56 IBD patients (43 Crohn's disease and 13 ulcerative colitis) with perianal complaints underwent anorectal function evaluation (AFE) (baseline). For follow-up, they were approached between 2010 and 2012 by sending questionnaires including Inflammatory Bowel Disease Quality of Life Questionnaire (IBDQ), Perianal Disease Activity Index (PDAI), faecal incontinence scale (Vaizey) and an invitation for AFE.

RESULTS

At follow-up, 46 patients (82 %) were available, 9 (16 %) were lost and 1 (2 %) had died. Thirty patients returned the questionnaires of which 17 also underwent AFE. The remaining 16 patients were interviewed by phone and were only willing to mention their anorectal complaints. Median follow-up was 14 year. In 25 of the 46 patients (54 %), perianal complaints persisted faecal incontinence (n = 7); soiling (n = 13) and active fistula (n = 5). Eighteen (39 %) patients had an active fistula at baseline and three persisted at follow-up. Two developed a new fistula. Mean IBDQ, Vaizey and PDAI were 178 (SD 29), 7 (SD 5) and 4.2 (SD 3.0), respectively. In 17 patients, who underwent AFE, anal endosonography showed healing in nine of the ten fistulas. Anal pressures as well as rectal capacity remained unaltered in the individual patient, but showed a large range within the group.

CONCLUSION

After 14 years, 54 % of the IBD patients with perianal lesions still have mild complaints. The quality of life remained moderate over a long period, which is concerning.