Background & Aims
Female sex is a well-known risk factor for chronic postoperative inguinal hernia pain [CPIP] [1]. Other notable risk factors for CPIP are younger age, preoperative pain, early postoperative pain, anxiety, and pain catastrophizing [1-6]. The extent to which sex difference in postoperative pain after inguinal hernia repair are due to confounding variables is unclear. Few studies that compare the sexes have matched males and females on important possible confounders [7]. The objective was to compare pain and related psychological factors 3 months [3M] and 1 year [1Y] after surgery between a matched sample of male and female primary unilateral inguinal hernia repair patients.
Methods
Male and female participants were compared by manually matching one-to-one on 10 clinical and demographic variables potentially related to pain. The 10 matching variables were age, body mass index (BMI, deciles), smoking status (Yes/No), preoperative (PP) depression and anxiety (PHQ), living status (alone or with others), American Society of Anesthesiologist physical status health classification (ASA), PP persistent pain, PP hernia pain, PP pain catastrophizing (PCS), and nerve handling during surgery (divided, not seen, or preserved). Matching was done as closely as possible. Descriptive statistics (mean ± standard deviation and frequency) as well as numerical rating scales [NRS] from 0-10 were used. Statistical tests were performed using Chi-square or Fisher’s Exact test for categorical data and independent samples t-test or non-parametric equivalent tests for numerical scores. P<0.05 is reported as statistically significant. To control Type I error, Bonferroni correction was used.
Results
Twenty-eight matched male-female pairs with 3M questionnaire results were compared. The average age preoperatively was 56.18±12.48 years. At 3M PO, 18 females and 6 males had pain (p=.001), with females reporting more frequent (p=.004) and longer durations (p=.005) of pain episodes. The 3M PO brief pain inventory [BPI] NRS results showed that females had higher worst (1.61±1.85 vs 0.32±0.77, p=.002), average (0.86±1.08 vs 0.14±0.45, p=.002), and pain now (0.43±1.20 vs 0, p=.010) than males. From the same sample of matched pairs, 21 male-female pairs had available data at 1Y. For the remaining pairs, one or both of the male-female participants’ 1Y questionnaire data were missing due to loss to follow up. Significant differences were not found in the incidence, frequency, or duration of pain between the sexes at 1Y. Significant differences were not found at the 3M or 1Y time point between the sexes related to pain interference with daily activities, PHQ, PCS, or resilience.
Conclusions
After matching on important confounders, differences were still found in the pain incidence and intensity at 3 months after primary unilateral inguinal hernia repair, suggesting that other factors are responsible for the differences. However, by 1-year after surgery the differences were no longer significant.
References
1.Reinpold W. (2017) Risk factors of chronic pain after inguinal hernia repair: a systematic review. Innov Surg Sci 2(2):61-68.
2.Langeveld HR, Klitsie P, Smedinga H, Eker H, Van’t Riet M, Weidema W, et al. (2015) Prognostic value of age for chronic postoperative inguinal pain. Hernia 19(4):549-555.
3.Romain B, Fabacher T, Ortega-Deballon P, Montana L, Cossa JP, Gillion JF, et al. (2021) Longitudinal cohort study on preoperative pain as a risk factor for chronic postoperative inguinal pain after groin hernia repair at 2-year follow up. Hernia 26(1):189-200.
4.Callesen T, Bech K, Kehlet H. (1999) Prospective study of chronic pain after groin hernia repair. Brit J Surg 86(1):1528-1531.
5.Munafo MR and Stevenson J. (2001) Anxiety and surgical recovery- reinterpreting the literature. J Psychosom Res 51:589-596.
6.Granot M and Ferber SG. (2005) The roles of pain catastrophizing and anxiety in the prediction of postoperative pain intensity- a prospective study. Clin J Pain 21:439-445.
7.The HerniaSurge Group. (2018) International guidelines for groin hernia management. Hernia 22:1-165. doi:10.1007/s10029-017-1668-x
Presenting Author
Marguerite Mainprize
Poster Authors
Topics
- Gender/Sex Differences