Groin hernia repair : evaluation of clinical impacts and interactions of mesh and mesh fixation

AIMS

The project underlying this thesis aimed to identify and quantify relative risk differences in reoperation rate (Papers I and II) and chronic postoperative inguinal pain (CPIP) following surgical repair of groin hernias, depending on diverse types of mesh implants and modes of mesh fixation.

Paper III was a preparatory study to identify relevant preoperative effect modifiers, to streamline an upcoming CPIP study on mesh/fixation combinations in laparoscopic groin hernia repair.

METHODS

The 3 individual studies were each based on large, nationwide cohorts from the Swedish Hernia Registry (SHR). For statistical analysis, Papers I and II used multivariable Cox regression. Paper III used multivariable logistic regression. P- values are 2-tailed with 95% confidence intervals (CI).

The predictors of interest were:

Paper I: Fixation suture material in the Lichtenstein repair: permanent vs long- term absorbable vs short-term absorbable sutures.

Paper II: Mesh/fixation combinations in laparoscopic repairs. Standard polypropylene mesh (StdPPM) vs lightweight mesh (LWM); and metal tacks vs absorbable tacks vs fibrin glue vs no fixation.

Paper III: Preoperative risk factors in laparoscopic repairs.

RESULTS

Paper I: 82,015 Lichtenstein repairs were included. With permanent sutures as reference (HR = 1)

• long-term absorbable sutures (HR 1.1; CI 0.8-1.6; P = 0.49) were not associated with an increased risk for reoperation .
• short-term absorbable sutures associated with a more than doubled reoperation risk (HR, 2.2; CI 1.7-3.0; P <0.001).

Paper II: Of 25,190 repairs, 924 (3.7%) were later reoperated for recurrence. The lowest, mutually equivalent, reoperation risks were associated with:

• StdPPM without fixation (reference = HR, 1)
• StdPPM + metal tacks (HR, 0.8; CI 0.4 - 1.4; P = 0.39),
• StdPPM + fibrin glue (HR, 1.1; CI 0.7 - 1.6; P = 0.63)
• LWM + fibrin glue (HR, 1.2; CI 0.95 - 1.6; P = 0.11)

All other LWM options correlated with increased risk:

• LWM + metal tacks (HR, 1.6; CI 1.02 - 2.6; P = 0.040)
• LWM + absorbable tacks (HR, 2.4; CI 1.5 - 3.8; P <0.001)
• LWM without fixation (HR, 2.0; CI 1.5 - 2.5; P <0.001).

Paper III: From 82 surgical centers, 15,363 patients (33% female) were eligible, with mean age 57 years. Of 10,524 (69%) questionnaire respondents, 3,026 (29%) had CPIP according to our primary definition used for the main analysis, and 1,614 (15%) according to our secondary definition. The response rate varied significantly across some variables, particularly age.

Preoperative predictors significantly associated with CPIP were:

• female sex (OR, 1.2; CI, 1.1-2.3)
• younger age (eg, <45 vs ≥65 years; OR, 1.4; CI, 1.2-1.6)
• overweight (OR 1.3; CI 1.2-1.5) and obesity (OR, 1.6; CI, 1.3-1.9)
• ASA 2 (OR, 1.1; CI, 1.01-1.2), and ASA ≥3 (OR, 1.4; CI, 1.2-1.7)
• recurrent hernia (OR, 1.3; CI, 1.2-1.5)
• femoral hernia (OR, 1.3, ;CI, 1.1-1.6) vs lateral and/or medial hernias
• small (<1.5cm) vs large (>3cm) hernia defect Ø (OR, 1.2; C,I 1.03-1.4)

CONCLUSIONS

Paper I:

• Regarding recurrence risk, long-term absorbable sutures are an excellent alternative to permanent sutures for mesh fixation in Lichtenstein inguinal hernioplasty.
• Short-term absorbable sutures entail an independent risk factor for recurrence and should therefore be avoided.

Whether there is a difference in impact on CPIP between these 2 suture alternatives needs to be explored.

Paper II:

• With StdPPM, neither mechanical nor glue fixation associated with improved outcomes. Thus, for this mesh category, we recommend no fixation. This is also, by far, the least expensive option.
• With LWM, we recommend fibrin glue fixation, which was the only LWM alternative on par with non-affixed StdPPM.

Paper III:

• This study identified relevant preoperative CPIP risk factors and quantified their relative impact.
  The results can be useful in designing and interpreting other studies.
• It also highlights selection bias, which appears to be a major general issue in CPIP studies but has not been satisfactorily addressed in prior reports. Future CPIP research should incorporate strategies to mitigate selection bias further.

List of scientific papers

I. Novik B, Nordin P, Skullman S, Dalenbäck J, Enochsson L. More recurrences after hernia mesh fixation with short-term absorbable sutures: A registry study of 82 015 Lichtenstein repairs. Arch Surg. 2011;146:12-17. https://doi.org/10.1001/archsurg.2010.302

II. Novik B, Sandblom G, Ansorge C, Thorell A. Association of mesh and fixation options with reoperation risk after laparoscopic groin hernia surgery: A Swedish Hernia Registry study of 25,190 totally extraperitoneal and transabdominal preperitoneal repairs. J Am Coll Surg 2022;234:311-325. https://doi.org/10.1097/XCS.0000000000000060

III. Novik B, Sandblom G, Thorell A. Preoperative risk factors for chronic pain after laparoscopic groin hernia repair: A Swedish Hernia Registry study. 2024. [Submitted]