Autologous Microfragmented Adipose Tissue Injection in Refractory Complex Crohn's Perianal Fistulas: Long-Term Results at 6.7 Years Mean Follow-up.

Background: Nowadays, there is a clear need for new viable therapeutic options to face complex perianal Crohn's disease (PCD). Results of our previous pilot study demonstrated the efficacy and safety of local injection of autologous microfragmented adipose tissue (MFat) in this setting. This study aims to evaluate the long-term follow-up results in the same cohort of patients.

Methods: Data on clinical and radiological remission and surgical recurrence rates were prospectively collected on the 15 patients with complex fistulizing PCD refractory to combined bio-surgical therapy, originally treated with local MFat injection, with a mean 6.7 years follow-up.

Results: In our previous study, at 24-week follow-up, combined remission was reported in 66.7% of patients, while clinical remission was achieved in 93% of cases. At a 6.7-year follow-up, 9 of the 10 healed patients maintained remission. The patient with recurrence was successfully reoperated. Three out of 5 patients who failed primary combined remission were retreated, with 2 obtaining combined remission and 1 failing. One patient refused any subsequent treatment due to good quality of life. The last patient presented delayed healing at a 1-year follow-up. Overall success rate after rescue therapy at the final follow-up reached 86.6%. Safety was maintained throughout all follow-up periods.

Conclusions: This is the longest follow-up published trial on MFat injection for PCD. Our results show that patients who achieved closure in the first 24 weeks sustained response at long-term evaluation. In addition, there may be a rationale in repeating treatment as rescue therapy in not responding to patients.