Influence of laparotomy closure technique on collagen synthesis in the incisional region

Variations of suture technique have an influence on the mechanical strength of laparotomy wounds. To investigate whether these differences in biomechanical properties influence collagen synthesis in the incisional region, an animal experiment on laparotomy closure was performed.

In 100 rats median laparotomies were closed with polypropylene. Continuous and single sutures were applied with variations of suture length to wound length (SLWL) ratio and suture tension.

Tissue samples from the incisional region after 2 and 4 weeks were analysed spectro-photometrically for the concentration of collagen protein and by digital image analysis for the percentage of collagen type III.

Running closure with an SLWL ratio >or=4:1 resulted in a significantly higher concentration of collagen protein than single sutures with the same SLWL ratio. In contrast, single closure with an SLWL ratio <4:1 led to in a higher collagen protein concentration than running closure with the same SLWL ratio. With an SLWL ratio >or=4:1 running sutures resulted in a significant reduction of the percentage of collagen type III after 4 weeks compared to single sutures. Closure with high suture tension led to a significant reduction of collagen protein between the 2nd and 4th week but left the percentage of collagen type III mostly unaffected.

Suture technique, SLWL ratio, and suture tension have an effect on the ultrastructural composition of the regenerating tissue. This influence outlasts the period of tissue restructuring during which the presence of sutures in the incisional edges is absolutely required. Running sutures with an SLWL ratio >or=4:1 and low suture tension promote a favourable collagen composition of the incisional region.