Biomechanical abdominal wall model applied to hernia repair

Lyons, Mathew; Mohan, Helen; Winter, D. C.; Simms, Ciaran

doi:10.1002/bjs.9687

Cited by 24 publications

(8 citation statements)

References 26 publications

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“…In our series, reduced OL was used to destabilize primarily stable repairs and to assess the relative performance of fixation methods (Table 2 ; Figures 2 – 5 ). Using slow pushing or bending forces, an OL of 5 cm is sufficient for most meshes to successfully bridge a 5-cm hernial orifice ( 23 ). In clinical data, MDAR rather than OL was found to markedly influence recurrence ( 4 – 6 ).…”

Section: Discussionmentioning

confidence: 99%

Assessing the GRIP of Ventral Hernia Repair: How to Securely Fasten DIS Classified Meshes

et al. 2018

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Recurrences are frequently observed after ventral hernia repair. Based on clinical data, the mesh–defect area ratio (MDAR) can lead to lower recurrence rates. Using dynamic intermittent strain (DIS) in a pig tissue model, MDAR can be modified to give a measure called grip to better assess the mechanical stability of ventral hernia repair. The focus of this experimental study is to assess the different aspects of mesh overlap (OL) and fixation only in bridging repair of ventral hernias. DIS mimics coughing actions in an ex vivo model with the repetition of submaximal impacts delivered via a hydraulically driven plastic containment. Tissue derived from pig bellies simulates a ventral hernia with varying defect sizes. MDAR is calculated from the hernia orifice and the mesh OL. Commercially available meshes were strengthened with glue, tacks, and sutures to bridge the defects. The reconstructions are strained with up to 425 dynamic impacts. The grip of each repair is assessed using MDAR modified by the strength of the fixation. The DIS classification is based on bridging of a 5 cm ventral hernia orifice with an OL of 5 cm in a sublay position. The classification discriminates meshes properties upon DIS strain. MDAR is calculated to be 9 under these conditions. Decreasing the OL or increasing the hernia orifice reduces MDAR to numbers below 9. MDAR is modified to reach GRIP. Closure of the peritoneum adds about 4 to the grip given by MDAR. The multiplying factor of a transmural suture or one tack of Securestrap® or Protack® is 0.5 times the number of tacks applied. The multiplier given by a bonding spot of Glubran® is similar to that of an Absorbatack® being 0.33. Plotting the likelihood of a bridging repair to survive more than 400 DIS impacts versus the grip estimated from the factors given above, the grip to be passed for a durable repair is 10 for Parietex Progrip®, and Dynamesh Cicat® and 25 for Dynamesh IPOM®. Clinical data previously published can be reculculated to assess MDAR and permit an estimation of the grip of the reconstruction. In these recalculations, a correlation between MDAR and long-term recurrence rates is found. A dimensionless number called grip can be calculated. The grip can be modified by fixation in a reproducible way. A higher grip can improve the durability of ventral hernia repair. We believe that a higher grip leads to lower recurrence rates in the clinical setting.

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Section: Discussionmentioning

confidence: 99%

Assessing the GRIP of Ventral Hernia Repair: How to Securely Fasten DIS Classified Meshes

et al. 2018

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“…With submaximal load no failure of the mesh-tissue-interface is observed with increasing pressures below a threshold of about 150 mmHg [ 4 , 11 ]. In patients, up to 400 coughs were observed within 24 h which can reach intraabdominal pressures well above 200 mmHg [ 12 , 13 ].…”

Section: Discussionmentioning

confidence: 99%

Increasing hernia size requires higher GRIP values for a biomechanically stable ventral hernia repair

Kallinowski

Gutjahr

Vollmer

et al. 2019

Annals of Medicine and Surgery

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Background Increasing hernia sizes lead to higher recurrence rates after ventral hernia repair. A better grip might reduce the failure rates. Material and methods A biomechanical model delivering dynamic intermittent strain (DIS) was used to assess grip values at various hernia orifices. The model consists of a water-filled aluminium cylinder covered with tissues derived from pig bellies which are punched with a central defect varying in diameter. DIS was applied mimicking coughs lasting for up to 2 s with peak pressures between 180 and 220 mmHg and a plateau phase of 0.1 s. Ventral hernia repair was simulated with hernia meshes in the sublay position secured by tacks, glue or sutures as needed to achieve certain grip values. Grip was calculated taking into account the mesh: defect area ratio and the fixation strength. Data were assessed using non-parametric statistics. Results Using a mesh classified as highly stable upon DIS testing (DIS class A) a reduced overlap without fixation led to early slippage (p < 0.001). With the application of 16 fixation points, transmural sutures were better than tacks with Securestrap ® being better than Absorbatack ® (p < 0.001). Plotting the likelihood of a durable repair as a function of the calculated grip higher grip values were needed with increasing hernia diameter to achieve biomechanical stability. This is important for clinical work since the calculated grip values both from a registry and from published data tend to drop as hernia sizes increase indicating biomechanical instability. Conclusion The experimental work reported here demonstrates for the first time that higher grip values should be reached when repairing larger ventral hernias.

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“…The biomechanical abdominal model has been described previously ( Fig . ). This model simulates intra‐abdominal pressure and was designed to optimize suture‐based closure approaches following a reproducible midline laparotomy incision of the linea alba.…”

Section: Methodsmentioning

confidence: 99%

Optimized wound closure using a biomechanical abdominal model

Cooney

Kiernan

Winter

et al. 2018

British Journal of Surgery

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These findings suggest using a small bite separation (5 mm) and large bite width (16 mm) during abdominal wound closure may be optimal. Surgical relevance Suturing techniques for midline abdominal wall incisions vary between surgeons. This experimental study suggests substantial potential for improved tissue apposition by changing the suturing approach from the traditional clinical recommendation of 10 mm for both bite separation and bite width to a bite separation of 5 mm and a bite width of 16 mm. These findings support recent European Hernia Society guidelines and the recent randomized STITCH (Suture Techniques to Reduce the Incidence of The inCisional Hernia) trial, which found that small separations are more effective than large separations, but suggest that they should be combined with large bite depths.

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Biomechanical abdominal wall model applied to hernia repair

Cited by 24 publications

References 26 publications

Assessing the GRIP of Ventral Hernia Repair: How to Securely Fasten DIS Classified Meshes

Assessing the GRIP of Ventral Hernia Repair: How to Securely Fasten DIS Classified Meshes

Increasing hernia size requires higher GRIP values for a biomechanically stable ventral hernia repair

Optimized wound closure using a biomechanical abdominal model

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