Retrospective Study
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jun 28, 2021; 27(24): 3643-3653
Published online Jun 28, 2021. doi: 10.3748/wjg.v27.i24.3643
Stem cell injection for complex anal fistula in Crohn’s disease: A single-center experience
Oliver Schwandner
Oliver Schwandner, Department of Proctology, Krankenhaus Barmherzige Brueder, Regensburg 93049, Germany
Author contributions: Schwandner O performed the research and wrote the paper.
Institutional review board statement: According to the Ethics Committee of the Bavarian State Chamber of Physicians retrospective reviews of anonymized patient data do not require ethical approval, No. 2021-1022.
Informed consent statement: Patients were not required to give informed consent to the study because the retrospective analysis used anonymized clinical data that were obtained after each patient agreed to treatment by written consent.
Conflict-of-interest statement: The author had honoraria from Takeda and Medtronic for invited presentations during advisory board meetings and satellite symposia. Neither funding nor financial support was administered for the current study.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Corresponding author: Oliver Schwandner, FASCRS, MD, Professor, Department of Proctology, Krankenhaus Barmherzige Brueder, Pruefeninger Str 86, Regensburg 93049, Germany.
Received: January 9, 2021
Peer-review started: January 9, 2021
First decision: January 23, 2021
Revised: March 10, 2021
Accepted: June 4, 2021
Article in press: June 4, 2021
Published online: June 28, 2021

Despite tremendous progress in medical therapy and optimization of surgical strategies, considerable failure rates after surgery for complex anal fistula in Crohn’s disease have been reported. Therefore, stem cell therapy for the treatment of complex perianal fistula can be an innovative option with potential long-term healing.


To evaluate the results of local administration of allogenic, adipose-derived mesenchymal stem cells (darvadstrocel) for complex anal Crohn’s fistula.


All patients with complex anal fistulas associated with Crohn’s disease who were amenable for definite fistula closure within a defined observation period were potential candidates for stem cell injection (darvadstrocel) if at least one conventional or surgical attempt to close the fistula had failed. Darvadstrocel was only indicated in patients without active Crohn’s disease and without presence of anorectal abscess. Local injection of darvadstrocel was performed as a standardized procedure under general anesthesia including single-shot antibiotic prophylaxis, removal of seton drainage, fistula curettage, closure of the internal openings and local stem cell injection. Data collection focusing on healing rates, occurrence of abscess and follow-up was performed on a regular basis of quality control and patient care. Data were retrospectively analyzed.


Between July 2018 and January 2021, 12 patients (6 females, 6 males) with a mean age of 42.5 (range: 26-61) years underwent stem cell therapy. All patients had a minimum of one complex fistula, including patients with two complex fistulas in 58.3% (7/12). Two of the 12 patients had horse-shoe fistula and 3 had one complex fistula. According to Parks classification, the majority of fistulas were transsphincteric (76%) or suprasphincteric (14%). All patients underwent removal of seton, fistula curettage, transanal closure of internal opening by suture (11/12) or mucosal flap (1/12) and stem cell injection. At a mean follow-up of 14.3 (range: 3-30) mo, a healing rate was documented in 66.7% (8/12); mean duration to achieve healing was 12 (range: 6-30) wk. Within follow-up, 4 patients required reoperation due to perianal abscess (33.3%). Focusing on patients with a minimum follow-up of 12 mo (6/12) or 24 mo (4/12), long-term healing rates were 66.7% (4/6) and 50.0% (2/4), respectively.


Data of this single-center experience are promising but limited due to the small number of patients and the retrospective analysis.

Keywords: Complex anal fistula, Crohn’s disease, Stem cell therapy, Mesenchymal stem cells, Darvadstrocel, Treatment, Surgery, Outcomes

Core Tip: This is a retrospective single-center study on the application of allogenic, adipose-derived mesenchymal stem cells (darvadstrocel) for complex perianal fistula associated with Crohn’s disease, providing structured inclusion and exclusion criteria for 12 patients. The current data demonstrate that the management by local stem cell therapy is safe and effective. However, based on the small patient sample size and the retrospective analysis of routine clinical data, a general conclusion remains limited. Therefore, further prospective controlled studies are mandatory to assess the definite role of adipose-derived mesenchymal stem cells for complex anal fistula in Crohn’s disease.