Outcomes of surgery on patients with a clinically inapparent inguinal hernia as diagnosed by ultrasonography

Chronic post-operative inguinal pain (CPIP) is the most significant complication following inguinal hernia repair. Patients without a palpable hernia prior to surgery seemed to report more CPIP. Our aim was to evaluate the effects of surgery on patients with a clinically inapparent inguinal hernia as diagnosed using ultrasonography. A total of 179 hernia repairs in patients with a positive ultrasonography but negative physical examination were analysed retrospectively. Patients with recurrent hernias, femoral hernias or previous surgery to the inguinal canal were excluded. The primary outcome was the presence of chronic postoperative inguinal pain (pain > 3 months postoperatively). Data on preoperative complaints, surgical technique and findings during ultrasonography and surgery were also studied in relation to the development of CPIP. A quarter (25.1%) of the patients reported chronic postoperative pain. Female gender (p = 0.03), high BMI (p = 0.04) and atypical symptoms prior to surgery (p < 0.001) were significant univariate risk factors for developing CPIP. Logistic regression showed a significant association between atypical symptoms and CPIP [OR = 6.31, p < 0.001, 95% CI (2.32, 17.16)], which was still present after correction for the significant univariate variables [OR = 4.23, p = 0.02, 95% CI (1.26, 14.21)]. Patients with a clinically inapparent inguinal hernia as diagnosed using ultrasonography report a high incidence of CPIP after elective hernia repair. Patients with atypical groin pain prior to surgery are especially prone to CPIP. It is questionable whether these hernias should be classified and treated as symptomatic inguinal hernias. The results advocate taking other causes of groin pain into consideration before choosing surgical treatment.