OBJECTIVE We evaluated routine intraoperative residual rectourethral fistula measurement (IRRFM) in 20 consecutive male imperforate anus with recto-bulbar (RB; n=12) or recto-prostatic (RP; n=8) fistula during laparoscopically assisted anorectal pull-through (LAARP) for preventing incomplete fistula excision (IFE) on mid-term follow-up. METHODS Twenty consecutive LAARP performed at a mean age of 10months (range: 3-30) followed-up for a mean of 4.8years (range: 1.5-9) were reviewed. IRRFM involves using a calibrated catheter and a cystoscope to measure the distance between where dissection was ceased at the rectal end and the urethral orifice (Figure). Dissection and IRRFM were repeated until the fistula was <5mm, then tied, and divided. Magnetic resonance imaging (MRI) and pelvic ultrasonography were used to exclude IFE and cyst formation. RESULTS Residual fistula was 4-18mm on initial IRRFM. Unless measured, dissection cannot proceed to <5mm safely with poentical for urethral injury or IFE. With experience, initial IRRFM were shorter, especially in RP (Table 1). Before the IRRFM era, our incidence of cysts was 2/11 (18%), but here we found no evidence of cyst formation on MRI, no dysuria, and no urinary tract infections. CONCLUSIONS Mid-term review demonstrates that IFE can be prevented successfully by IRRFM during LAARP. METHODS Case Series with no Comparison Group, Level IV.