Evaluation of absorbable and permanent mesh fixation devices: adhesion formation and mechanical strength.

PURPOSE: Laparoscopic ventral hernia repair is commonly performed with mesh prostheses; however, there is no standard for fixation devices used to secure mesh to the abdominal wall. This study is a functional comparison of novel, screw-type absorbable and permanent fixation devices with a traditional titanium fixation device. METHODS: Fifteen pigs each underwent the laparoscopic placement of two 11 × 14-cm mesh prostheses and were randomized for mesh fixation with either titanium spiral tacks (TS), absorbable screw-type fasteners (SF), or permanent screw-type fasteners (PF) (n = 10 mesh prostheses for each fixation group). Adhesions were assessed laparoscopically at 4 weeks. The fixation devices were also embedded in porcine abdominal rectus muscle for ex vivo mechanical testing along with partial thickness polypropylene suture (PR) as a control group (n = 40 for each group). Maximum pull-off forces were measured. All statistical tests were two-tailed, and a P-value < 0.05 was considered to be significant. RESULTS: The mean tenacity adhesion scores were 1.40 ± 0.52 (PF), 1.7 ± 0.82 (SF), and 2.6 ± 1.07 (TS). Adhesions in the PF group were significantly less tenacious compared with the TS group (P = 0.01). Quantitative adhesion scores were not significantly different among groups. The maximum pull-off forces, measured in Newtons, were 28.61 N ± 4.89 N (TS), 22.71 N ± 7.86 N (SF), 16.98 N ± 7.59 N (PF), and 20.83 N ± 6.25 N (PR). The pull-off force in the TS group was higher than all of the other groups (P < 0.001). The SF group also had a higher pull-off force compared with the PF group (P < 0.001). CONCLUSIONS: The screw-type absorbable and permanent fixation devices provided adequate fixation and were associated with decreased adhesions in this porcine model.

High light intensity: a critical factor in the wind-tunnel flight of two scarabs, the rose chafer and Japanese beetle.

We analyzed the flight of the rose chafer Macrodactylus subspinosus (F.) (Melolonthinae: Scarabaeidae) and the Japanese beetle Popillia japonica Newman (Rutelinae: Scarabaeidae) in a wind tunnel with controlled humidity, temperature, light, and airflow. The data indicate that an optimum combination of light and temperature dramatically improves their response to lures. Both species took off upwind, oriented to, and contacted the odor source well (40-60%) when light intensity was > 50% of a clear day, temperature was 26-27 degrees C, and relative humidity was 65-75%.