Cause and Effect versus Confounding—Is There a True Association between Caudal Blocks and Tubularized Incised Plate Repair Complications?

Abstract

We studied the impact of caudal block vs dorsal penile block on the rate of urethrocutaneous fistula and glans dehiscence in children who underwent hypospadias repair. We retrospectively reviewed the records of 849 consecutive patients who underwent tubularized incised plate repair between 2004 and 2015. A total of 331 cases with incomplete medical records, other techniques and redo repair were excluded. The preference for caudal block was based on anesthesiologist discretion. Age at surgery, meatal location, preoperative testosterone stimulation, type of regional anesthesia (caudal block vs dorsal penile block), degree of ventral curvature, surgeon expertise and complications (urethrocutaneous fistula/glans dehiscence) were captured. Univariate and multivariable analyses were done of risk factors for complications. Median age at surgery was 18 months and median followup was 6months. Of 518 patients 405 (78%) had distal and 113 (22%) had mid shaft/proximal defects. Complications developed in 37 cases (7%), including urethrocutaneous fistula in 21 (19 with a caudal block and 2 with a dorsal penile block) and glans dehiscence in 16 (13 with a caudal block and 3 with a dorsal penile block). On univariate analysis preoperative testosterone stimulation vs no preoperative testosterone stimulation (13.0% vs 6.2% of cases, p = 0.04), mid shaft/proximal vs distal defects (15.9% vs 4.7%, p <0.01) and caudal block (8.7% vs 3.3%, p = 0.03) were significantly associated with more complications. However, on multivariable analysis the associations of preoperative testosterone stimulation (OR 1.2, 95% CI 0.4-3.7) and caudal block (OR 2.4, 95% CI 0.9-6.4) with complications did not hold. Only the combination of meatal location/ventral curvature remained as an independent risk factor for urethrocutaneous fistula/glans dehiscence (OR 2.4, 95% CI 1.1-5.7, p = 0.04). Our data indicate that hypospadias severity and not the type of regional anesthesia was the only risk factor significantly associated with postoperative complications. To confirm these findings and provide strong and definitive evidence on this topic a well powered, randomized, controlled trial is clearly required.