Current management of anal fistulas in Crohn’s disease

Abstract

Anal fistulas occurring in Crohn's disease (CD) comprise a risk factor of severe course of inflammation. They are frequently intractable due to various factors such as penetration of the anal canal or rectal wall, impaired wound healing, and immunosuppression, among others. Anal fistulas typical to CD develop from fissures or ulcers of the anal canal or rectum. Accurate identification of the type of fistula, such as low and simple or high and complex, is crucial for prognosis as well as for the choice of treatment. If fistulotomy remains the gold standard in the surgical treatment of the former, it is contraindicated in high and complex fistulas due to possible risk of damage to the anal sphincter with subsequent faecal incontinence. Therefore, the latter require a conservative and palliative approach, such as an incision and drainage of abscesses accompanying fistulas or prolonged non-cutting seton placement. Currently, conservative, sphincter-preserving, and definitive procedures such as mucosal advancement or dermal island flaps, the use of plugs or glue, video assisted anal fistula treatment, ligation of the intersphincteric track, and vacuum assisted closure are gaining a great deal of interest. Attempting to close the internal opening without injuring the sphincter is a major advantage of those methods. However, both the palliative and the definitive procedures require adjuvant therapy with medical measures.

Oral vitamin D supplementation induces transcriptomic changes in rectal mucosa that are linked to anti-tumour effects

“…However, a recent randomised-control trial (RCT) reported an association between supplementation, vitamin D receptor genotype, and risk of colorectal adenoma, supporting the premise that the beneficial effect may be causal [ 3 ]. Meanwhile, vitamin D-related genetic variation has been shown to influence the association between 25-OHD level and CRC survival [ 4 – 6 ], with a recent meta-analysis of RCT data strongly supporting a causal effect for vitamin D supplementation on CRC mortality [ 7 , 8 ].…”

Adipose-Derived Stem Cells Are an Efficient Treatment for Fistula-in-ano of Japanese Rabbit

“…Sphincter-saving operations should be preceded by prolonged drainage with a noncutting seton until inflammation within the fistulous track recedes [26]. Cutting setons are not recommended due to the risk of damage to the sphincter or deformation of the anus [25]. In our study, the rabbit fistulas are healing at the last time after noncutting setons, but the anal deformation is serious, and fistula has a long healing time with scar and inflammation left.…”

“…Prolonged placement of noncutting setons remains a “gold standard” in the palliative treatment of fistulas [25]. Sphincter-saving operations should be preceded by prolonged drainage with a noncutting seton until inflammation within the fistulous track recedes [26].…”

Factors Increasing the Risk of Recurrence in Fistula-in-ano

“…Besides the anatomical factors causing recurrent disease, several other comorbidities increase the risk of anal fistula recurrence. These factors include anal cancer [22], Crohn’s disease [23], diabetes [24], smoking [25], and an immunosuppressed state like HIV [26].…”