EP132 - Clinical Efficacy and Anal Function Outcomes of Surgical Intervention Combined with Ustekinumab in the Management of Perianal Fistulizing Crohn’s Disease

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Purpose/Background: To access the short-term and long-term clinical efficacy of surgical intervention combined with Ustekinumab(UST) in patients with active perianal fistulizing Crohn’s disease(CD), as well as its impact on anal function.

Methods/Interventions: A retrospective study was conducted to collect clinical data from patients with active perianal fistulizing CD who underwent surgical intervention combined with UST treatment at Longhua Hospital, Shanghai University of Traditional Chinese Medicine, between November 2021 and July 2024. The primary outcome measures included the clinical healing rate at week 8 post-treatment, as well as the relapse rate, Wexner Fecal Incontinence Score and anal anorectal manometry at week 52 post-treatment. Secondary observation indicators included CD Activity Index (CDAI), Perianal Disease Activity Index (PDAI), laboratory markers ( including C-reactive protein, erythrocyte sedimentation rate and fecal calprotectin), endoscopic remission rates, Van Assche score, and imaging healing rate at week 52 post-treatment.

Results/Outcomes: A total of 75 patients were enrolled in this study, comprising 65 males (86.7%) and 10 females (13.3%); the mean age was 27.5±11.5 years old (rang：14-69). Twelve cases (16%) presented with simple anal fistulas, while complex anal fistulas were observed in 63 cases (84%). According to Parks' classification, the distribution of fistula types was as follows: 33 intersphincteric, 23 transsphincteric, 11 suprasphincteric, and 8 extrasphincteric. Forty-one cases characterized by the presence of branches or associated abscess. The pre-treatment median CDAI score was 118.3 (range: 48-477), while the median PDAI score was 11.0 (range: 4-17). The surgical procedures utilized consisted of fistulotomy in 39 cases , transanal opening of intersphincteric space (TROPIS) in 19 cases, and a combination of video-assisted anal fistula treatment (VAAFT) combined FiLaC in 17 cases. The UST treatment was administered to all patients as a single intravenous infusion，with dosing based on weight: for patients weighting up to 55 kg a dose of 260 mg (2 vials) was given; for those weighing between 55 kg and 85 kg, a dose of 390 mg (3 vials) was administered; and for patients weighing over 85 kg, a dose of 520 mg (4 vials) was provided. Then followed by a subcutaneous dose of 90 mg after an initial of 8 weeks, and repeated every 8 weeks thereafter. It is important to note that no immunosuppressants or steroid were concurrently administered.
The clinical healing rate at eighth week was 76% (57/75). Meanwhile, at week 52, the relapse rate was only 2.6% (1/39) and there was a significant decrease in Wexner score from 1.0 (0,3) to 0.0 (0,1) (P＜0.01). Other parameters such as maximum anal pressure showed a significant improvement from 89.6±45.2mmHg to 111.8±26.2mmHg, resting anal pressure improved from10.0±9.9 mmHg to 34.4±12.6 mmHg, and maximal anal contraction time increased from 3.1±2.0s to 9.6±8.9s (all P＜0.01). Furthermore, the patients' CDAI and PDAI scores, CRP levels, fecal calprotectin concentrations, ESR values, Van Assche scores, and endoscopic scores all displayed significant reductions compared to pre-treatment (P < 0.01).

Conclusion/Discussion: The short-term clinical remission rate for perianal fistulizing CD, managed through a combination of surgical intervention and UST, stands at 76%, while a relapse rate of merely 2.6% was noted throughout the 52-week follow-up period. Moreover, this treatment approach significantly improves patients' anal function compared to their pre-treatment status.