Preliminary ex vivo and in vivo evaluation of laser bonding in dura mater

Dura mater repair represents a final and crucial step in cranial surgery: an inadequate dural reconstruction determines dreadful consequences that significantly increase morbidity and mortality rates. Different dural substitutes have been used with poor results. To overcome this issue, in previous studies we proposed a laser-based approach to the bonding of porcine dura mater, evidencing the feasibility of the laser assisted procedure. In this work, we present the optimization of the laser bonding approach ex vivo in porcine dura mater and in vivo in rats. An 810 nm cw laser was used to weld the ICG stained chitosan patch to the dura. The ex vivo tests enabled to optimize the laser parameters, using histology and leak pressure evaluation to study the bonding effect. The in vivo tests were performed on 32 adult Wistar rats: laser bonding was carried out in 16 rats, while a collagen matrix was used for duroplasty in the control group. After the treatment, the animals were left to recover and were observed in a 15 and 90 days follow up study. At sacrifice, the rats were anesthetized for fluid leakage pressure test; treated tissue was harvested and underwent standard histology. The results of this study pointed out that the laser bonding procedure can be used to close the dura mater, both ex vivo and in vivo. The thermal effect is limited and spatially confined. The technique can thus be proposed as a valid alternative to standard method for the closuring of dura mater in cranial surgery.