Treatment of perianal fistulas in Crohn's disease, seton versus anti-TNF versus surgical closure following anti-TNF (PISA): a randomised controlled trial

Wasmann, Katgm; de Groof, Ej; Stellingwerf, Me; D'Haens, Gr; Ponsioen, Cy; Gecse, Kb; Dijkgraaf, Mgw; Gerhards, Mf; Jansen, Jm; Pronk, A; van Tuyl, Sac; Zimmerman, Dde; Bruin, Kf; Spinelli, A; Danese, S; van der Bilt, Jdw; Mundt, Mw; Bemelman, Wa; Buskens, Cj