Caudal anesthesia is not associated with post-operative complications following distal hypospadias repair
Myron Yaster MD, Rita Agarwal MD, and Lynne G. Maxwell MD
For many of you, it will be easier to sleep at night after reading today’s PAAD. Two articles, one by Fischer et al.1 in the Journal of Pediatric Urology and the other by Adler and Austin2 in the journal Pediatric Anesthesia have finally, I hope, debunked the idea that there is an association between caudal anesthesia and increased hypospadias complications in either the short or long term. There just isn’t any! Since the early 2010’s there have been a series of small prospective and/or retrospective studies, some of which have found a higher incidence of postoperative complications which created a lot of angst and distress among the pediatric anesthesia community,3,4 while others have shown no association.5
For those of you who work in academic departments or have regular journal clubs, the articles by Fischer and in particular the one by Adler and Austin are well worth reading and discussing. The article by Adler highlights and explains the necessity of appropriately large sample sizes in these types of studies and the errors that occur when the studies are underpowered. Finally, as one of the PAAD’s executive council members, Dr. Jim DiNardo, always likes to point out, association is not the same thing as causation. Myron Yaster MD
Original article
Fischer KM, Van Batavia J, Hyacinthe N, Weiss DA, Tan C, Zderic SA, Mittal S, Shukla AR, Kolon TF, Srinivasan AK, Canning DA, Zaontz MR, Long CJ. Caudal anesthesia is not associated with post-operative complications following distal hypospadias repair. J Pediatr Urol. 2023 Aug;19(4):374-379. doi: 10.1016/j.jpurol.2023.03.019. Epub 2023 Mar 18. PMID: 37002025.
Original article
Adler AC, Austin PF. Caudal block for hypospadias repair: Unfolding the controversy through statistical analysis and how we can put it all to rest! Pediatr Anesth. 2024; 34: 108-111. doi:10.1111/pan.14786
Hypospadias is a common congenital anomaly and despite various reconstructive techniques has a very high complication rate (most commonly urethrocutaneous fistula), 10% for distal and close to 50% for proximal hypospadias!6 Since 2012, when Kundra et al.3, in a small randomized prospective study. proposed that caudal block was one potential risk factor for these complications, the use of caudal blockade for perioperative anesthesia and analgesia became very controversial.
Fischer et al., in a “large, single center (Children’s Hospital of Philadelphia), retrospective, homogenous study population > 1000 patients, with careful documentation of meatal location, robust long-term follow up, and inclusion of data from 14 surgeons over a 14-year period” found that “caudal nerve block is not associated with an increased risk of post-operative complications following distal hypospadias repair.”1 Additionally, the types of complications did not differ based on regional anesthesia technique (caudal or penile nerve block), with fistula being the most common complication in both groups. While time to complication seemed to be longer in the penile nerve block (PB) group on initial analysis, once age and type of repair were controlled for, there was not a significant difference based on block type.”1
In their meta-analysis, Adler and Austin found essentially the same thing, that is, there is no association between caudal block and risk of complications compared to penile nerve block. Adler and Austin also underlined the many problems with the original article by Kundra et al.,3 particularly its sample size (54 patients). The Kundra et al. study “was designed to compare the quality and duration of analgesia between caudal and penile blocks following hypospadias repair and not complications. The power analysis for this study was performed post hoc and done solely for the primary aim, the difference in opioid consumption.”2 “There was a complete lack of justification for the sample size being used to assess the strength of association between caudal and penile blocks (e.g., how often does the outcome of interest, in this case a complication occur and how confident can we be that this outcome did not happen due to chance or due to some other factor such as meatal location or surgical skill, etc.).”2 “For example, if we consider the incidence of complications to be 7% for penile blocks and contrasted this with the authors 19.2% complication rate for those with caudal blocks, performing a study to investigate the association between block and complications would require 238 patients (119 per group for both caudal and penile blocks). Given the small cohort in the Kundra et al. study, (26 and 27 patients with caudal and penile blocks respectively), the likelihood of not experiencing a complication simply by random chance alone (given a 7% rate of occurrence) is extraordinarily high.”2 It is important to emphasize that meatal location (proximal) is a significant confounder leading to a higher incidence of fistula formation.
We think one of the other important findings in both papers in today’s PAAD is the high complication rate following hypospadias repair6, particularly for proximal meatal defects. Did you know it was this high? Have you stopped doing caudals for hypospadias repair?
If you did, what (if any) regional technique did you use in its place? Will you start doing caudals again based on these studies? What are your thoughts? Send your comments to Myron who will post in a Friday Reader response.
References
1. Fischer KM, Van Batavia J, Hyacinthe N, et al. Caudal anesthesia is not associated with post-operative complications following distal hypospadias repair. Journal of pediatric urology 2023;19(4):374-379. (In eng). DOI: 10.1016/j.jpurol.2023.03.019.
2. Adler AC, Austin PF. Caudal block for hypospadias repair: Unfolding the controversy through statistical analysis and how we can put it all to rest! Pediatric Anesthesia 2024;34(2):108-111. DOI: https://doi.org/10.1111/pan.14786.
3. Kundra P, Yuvaraj K, Agrawal K, Krishnappa S, Kumar LT. Surgical outcome in children undergoing hypospadias repair under caudal epidural vs penile block. Paediatric anaesthesia 2012;22(7):707-12. (In eng). DOI: 10.1111/j.1460-9592.2011.03702.x.
4. Taicher BM, Routh JC, Eck JB, Ross SS, Wiener JS, Ross AK. The association between caudal anesthesia and increased risk of postoperative surgical complications in boys undergoing hypospadias repair. Paediatric anaesthesia 2017;27(7):688-694. (In eng). DOI: 10.1111/pan.13119.
5. Zaidi RH, Casanova NF, Haydar B, Voepel-Lewis T, Wan JH. Urethrocutaneous fistula following hypospadias repair: regional anesthesia and other factors. Paediatric anaesthesia 2015;25(11):1144-50. (In eng). DOI: 10.1111/pan.12719.
6. Long CJ, Canning DA. Hypospadias: Are we as good as we think when we correct proximal hypospadias? Journal of pediatric urology 2016;12(4):196.e1-5. (In eng). DOI: 10.1016/j.jpurol.2016.05.002.