A review of ventral hernia biomechanics

TL;DR

How biomechanics offer a quantitative framework for assessing healthy and damaged tissue behaviour is discussed, guiding personalised surgical strategies throughout the pre-, intra- and post-operative periods and highlights how mechanical principles shape hernia formation, diagnosis, and repair.

Abstract

Despite advancements in surgical techniques, hernia recurrence rates remain high, underscoring the need for improved understanding of abdominal wall behaviour. While surgeons are aware of many factors contributing to hernia occurrence (e.g obesity, smoking, surgical technique or site infection), it would be of interest to consider it as a biomechanical pathology. Indeed, an abdominal hernia arises from an imbalance between abdominal wall deformability and applied forces. This review article discusses how biomechanics offer a quantitative framework for assessing healthy and damaged tissue behaviour, guiding personalised surgical strategies throughout the pre-, intra-, and post-operative periods. The abdominal wall is a dynamic, load-bearing structure, continuously subjected to intra-abdominal pressure and mechanical stress. Its biomechanical properties, including elasticity and resistance to loading forces, dictate its function and response to surgical intervention. The linea alba is the stiffest component experiencing the highest stress, while the abdominal wall's anisotropic nature influences deformation patterns. Various experimental and computational methods enable biomechanical characterisation. Hernias represent mechanical failures at anatomical weak points. While surgeons qualitatively evaluate abdominal wall's biomechanics by estimating deformation and closure forces, functional imaging (elastography, dynamic acquisitions) could provide objective biomechanical insights. Hernia formation alters abdominal wall biomechanics, inducing greater mobility and elasticity. Surgical repair fundamentally alters the biomechanics of the abdominal wall. The choice of defect's suturing technique, mesh properties, placement, overlap and fixation methods (e.g. suture, tacks) significantly influence mechanical outcomes. Surgical repair tends to restore physiological biomechanics by re-establishing force transmission and hernia-induced excessive mobility. Suturing techniques, mesh selection and placement influence mechanical outcomes. However, optimal results require implants with mechanical properties mimicking native tissue. Lightweight meshes (<70 g/m2) placed in a retrorectus position, combined with a small-bite suture technique, have been associated with lower recurrence rates and improved post-operative function. By bridging biomechanics with surgical practice, this review highlights how mechanical principles shape hernia formation, diagnosis, and repair. A deeper integration of biomechanical principles into surgical decision-making could refine hernia management and lead to patient-specific, mechanics-informed strategies. For surgeons, this knowledge is not just academic - it is practical and can make a difference to patient outcomes.

Figures (5)

• Figure 1: Definition of the stresses applied on the abdominal wall
• Figure 2: Scheme of different ex vivo and in vivo experimental tests used for abdomen study. Ex vivo/bench tests: Different mechanical tests setup, example of the « Abdoman» model from Kroese et al., 2017 kroeseAbdoMANArtificialAbdominal2017 In vivo tests: a) Dynamic MRI during contraction b) EMG sensor kychotEnglishNeedleEMG2009c) Ultrasound of diastasis recti haggstromUltrasonographyDiastasisRecti2018d) MRI (left) and elastography (right) of healthy kidney mrelastoMRElastographyKidney2023
• Figure 3: Legend: Midline zone of abdominal wall in different stages: a) healthy, b) diastasis and c) hernia occurrence
• Figure 4: Scheme of suture with stitch spacing and bite size
• Figure 5: Numerical model's displacements obtained during coughing motion in three settings: healthy, with hernia and repaired abdominal walls, adapted from Todros et al.todrosComputationalModelingAbdominal2018