Page 351 - Demo

General discussion 34913the condylar neck and a tunnel to allow for reattachment and fixation of the enthesis were provided. By preserving the enthesis of the LPM with its bony attachment during the condylectomy, a wire could be threaded through the subcondylar tunnel, allow for fixation of the bony enthesis against the scaffold, which was intraoperatively filled with harvested, particulated bone. This was done as we hypothesized that it would allow for better promotion of osteosynthesis. Important to remark is that we experienced several difficulties concerning the reattachment of the LPM during surgery of the sheep. Proper dissection and retainment of the bony enthesis of the LPM was found to be more difficult in sheep compared to humans. As the fossa design was only adapted minimally from the human design, a spherical obstruction in the anteromedial side was experienced to properly reattach the LPM. This was most likely due to the inability to completely segment the LPM during the design process of the implant, leading to a slight underestimation of the total muscle volume. The enthesis of the LPM is also more caudally reattached than its original position, because of the thickness of the fossa component, which does not replace the glenoid fossa but is posed caudally to it. The arc of rotation with the origin as center displaces the enthesis medially. All UHMWPE parts were altered in such a way that nor did it affect the articulating surface, nor that the LPM experienced any obstruction anymore during its reconstruction. In the human application, the scaffold is foreseen on a extension in the condylar neck into the direction of the enthesis. Lastly, it was not always possible to properly evaluate if the bony part of the enthesis was directly touching the scaffold, because the mandibular component and the depth of the surgical cavity medially to it hindered vision.Clinical evaluation revealed nearly no weight loss of the included sheep, as well as laterotrusive movements to the healthy side of several randomly selected sheep, indicating a successful reattachment of the LPM. A radiological and subsequently histological evaluation substantiated this finding. Post-mortem radiological evaluation revealed 4 different conditions, however. In four of the sheep, there was no proper reconstruction of the LPM, with a large distance between the scaffold and the muscle. However it is Nikolas de Meurechy NW.indd 349 10-06-2024 11:12