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Lesch et al. Mini-invasive Surg 2023;7:25 https://dx.doi.org/10.20517/2574-1225.2023.31 Page 7 of 13

Figure 3. Likelihood of a secure closure (LOSC) until dislocation of the sublay mesh bridging a 5 cm round defect in bovine tissue as a
function of the number of DIS impacts, with peak pressures between 120 and 240 mmHg applied for 0.1 s.

LOSC rises by about 20 %.

These experiments resulted in the definition of load limit curves [Figure 4]. The curve illustrates the
significantly lower durability for higher maximum pressures (240 vs. 120 mmHg P = 0.0155). The
prolongation of the pressure plateau length showed the same effect (210 mmHg peak with a plateau length
of 0.4 s vs. 0.1 s P = 0.0078). The load limits for shorter pressure plateaus result in a similar correlation with
the LOSC. The graphs tend to run parallel.

A worst-case scenario with up to 1000 pressure peaks, respectively, postoperative coughs, is illustrated in
Figure 4.

Beyond the 425th DIS impact, about 10 % more failures occur. After the 500th impact up to the 1000th
impact, the durability remains stable [Figure 5].

When using the cover plate with the larger, round (ES 15 + 16) instead of the smaller, square opening (ES 14
+ all other ES), significantly higher failure rates occur (P = 0.00016). This is accompanied by a significantly
greater elongation (about 4 cm) and deformation of the tissue (P = 0.0357) when using the larger opening.
The results support the logical deduction that the greater elongation and deformation of the tissue increases
the likelihood of failure.

The incision elongates with the number of cyclic loads applied. The most deformation, so-called plastic
deformation, occurs during the first 100 DIS impacts. After that, only slight deformation of the tissue takes
place. A steady state of tissue deformation is reached after 100 DIS impacts.

Figure 6 illustrates that the major plastic deformation takes place during the first 100 DIS impacts. This is
also the period when most failures (72 %) occur [Figure 7]. After that, only 11%-18 % of the failures occur
every 100 impacts.

DISCUSSION
Cyclic loading as a new concept in abdominal wall reconstruction
[21]
Studies on tendons show that not the suture material but the tissue is the predominant weak point . The