Feasibility and safety of calcium alginate hydrogel sealant for the treatment of cryptoglandular fistula-in-ano: phase I/IIa clinical trial.

Aim: Complex perianal fistulas pose a challenge to the surgeon since the fistulous tract must be eliminated without impairing continence. Although without strong scientific evidence, some bibliography has demonstrated the efficacy of some sealants in the treatment of anal fistulas. We aimed to assess the feasibility and safety of calcium alginate hydrogel injections into the fistulous tract as treatment for trans-sphincteric cryptoglandular fistulas.

Methods: A prospective, single-centre, case series of this novel technique was conducted in a level 3 Spanish hospital, including patients diagnosed with trans-sphincteric perianal fistulas and treated with a calcium alginate hydrogel sealant. A strict follow-up was performed by an independent surgeon at 1, 3, 6 and 12 months. The main outcome measures were feasibility, safety (number of adverse events) and efficacy of the treatment.

Results: Twenty patients were treated. The treatment was performed for all patients. Seven adverse events related to the injection product or the surgical procedure were identified. After a 12-month follow-up, 12 patients were completely cured and eight were not cured, with a greater response in the first 6 months. These findings were confirmed by endoanal ultrasound, with a Cohen's kappa concordance rate of 0.89. No statistically significant differences were observed in pain measured using the visual analogue scale, faecal incontinence measured using the Wexner scoring system, and quality of life analysed by the SF-36 Health Survey.

Conclusion: The treatment was feasible, safe and with discrete satisfactory healing results. It also demonstrated an acceptable safety profile, without worsening of faecal incontinence, quality of life and pain following treatment.