Biomechanical strength of two laparoscopic herniorrhaphy techniques in a cadaveric diaphragm and in a neoprene model

Our objectives were to 1) Biomechanically compare two laparoscopic repair techniques; an automated suturing device and a stapling device to conventional open suturing, and 2) Evaluate a model for canine diaphragmatic tissue by comparisons to similar constructs in fresh diaphragms. We hypothesized that automated suturing is biomechanically superior to laparoscopic stapling in dogs, and that neoprene defect repair is an acceptable model for experimental cadaveric diaphragm herniorrhaphy.

Samples of diaphragm pars costalis were prepared with defects mimicking radial muscular tears. Defects were repaired using conventional open suturing, laparoscopic automated suturing, and laparoscopic stapling techniques. Similar defects were created in 6.35 mm thick single-sided neoprene. Samples were biomechanically tested across a biaxial loading machine. Site and mode of failure were noted for all samples.

In both the diaphragm muscle and neoprene, the laparoscopic stapling technique was significantly weaker. The neoprene model showed a similar failure load as the diaphragm in both laparoscopic techniques, and a similar stiffness in an open-sutured and stapled diaphragm compared to the neoprene samples. Site and mode of failure in neoprene were similar to cadaveric diaphragmatic tissue, but the overall median load-to-failure was higher for the neoprene.

The strength of laparoscopically repaired simulated diaphragmatic hernias was higher with an automated suture technique than with a stapling technique. Neoprene defect repair is an acceptable model of canine diaphragmatic herniorrhaphy for biomechanical testing.