Chronic postoperative inguinal pain (CPIP) after pediatric inguinal hernia repair-a retrospective analysis

Background: Surgical treatment of inguinal hernias in children is one of the most common operative procedures worldwide. During surgery for inguinal hernias in adults, chronic pain develops in approximately 10% of all cases. In children, there has been limited research to determine whether they may also develop this chronic postsurgical inguinal pain (CPIP). The aim of this study was to investigate the prevalence of CPIP in children after open inguinal hernia surgery and to identify possible risk factors and protective factors for the development of CPIP.

Methods: A single center retrospective analysis of patients aged 4 to 15 years who underwent inguinal hernia repair from 2020 to 2022 was performed. A detailed analysis based on the local database was used to analyze existing pre-existing conditions, perioperative information and the use of a cauda epidural block. A standardized follow-up questionnaire was used to evaluate the prevalence of CPIP and the duration of postoperative analgesic medication.

Results: A total of 176 cases were included in the detailed analysis. 3.4 % of the children complained CPIP 3 months after surgery with a mean follow-up period of 26.4 months. At the time of the survey, 50% of CPIP patients reported a resolving from chronic pain. Our analyzes showed a potential higher CPIP rate in females (83.3%; p=0.040), older children (8.3 years vs. 5 years; p=0.006) and chronic pain history (16.7% vs. 2.4%; p=0.038).Furthermore, Children mitght profit from a intraoperative cauda epidural block since we observed a lower rate of CPIP (66.7% (4/6) vs. 97% (164/170); p=0.019) in these patients.

Conclusion: We were able to identify initial risk factors such as female gender, older patient age and a history of chronic pain. In addition, we were able to obtain information on possible protective factors such as an intraoperative cauda epidural block and adequate postoperative analgesia. However, further studies are required to clarify the pathogenesis and to confirm predictors and protective factors in order to improve therapeutic approaches.