Judging causal associations in observational research on caudal anesthesia and hypospadias repair

Does caudal analgesia increase the rates of urethrocutaneous fistula formation after hypospadias repair? Systematic review and meta-analysis

INTRODUCTION

Caudal block analgesia is administered to lower the requirements of systemic and inhaled anesthetic drugs during hypospadias surgery. However, recent reports, all clustered in a short time-span have generated controversial and mutually opposing results while evaluating caudal block as an independent risk factor for urethroplasty-related complications after hypospadias repair. There is no consensus statement on the role of caudal block analgesia in formation of urethrocutaneous fistula (UCF) after hypospadias surgery. We performed a systematic review and meta-analysis of the studies evaluating the relative rates of UCF formation after hypospadias surgery in patients who were administered caudal block analgesia versus in those who were not.

METHODS

Electronic searches were performed using PubMed, PubMed Central, Google Scholar, Ovid, and the Cochrane library. Statistical analysis was performed using a fixed-effect model, odds ratios, risk ratios (RR), and heterogeneity (I2) were calculated. Funnel plot was used to assess for publication bias.

RESULTS

Seven studies with 1706 patients were included. Caudal block analgesia is associated with a significantly higher risk of UCF formation (RR: 1.81; 95% confidence interval [CI]: 1.30-2.53), (P = 0.0004) and other urethroplasty-related complications (RR 2.01; 95% CI: 1.48-2.74), (P < 0.00001) after hypospadias surgery. Funnel plots indicate some publication bias.

CONCLUSIONS

In patients undergoing hypospadias repair, administration of caudal analgesia is associated with a higher risk of UCF formation and other urethroplasty-related complications.