Page 187 - Demo

Animal experiment: Radiological analysis of the LPM reattachment1857was aseptically prepared. Xylocaine (1%) with 1/80.000 epinephrine was locally infiltrated at the jaw angle and over the zygomatic arch to achieve local vasoconstriction and anesthesia. A 4-cm incision was made over the posterior lower border of the mandible. The lateral surface and the angle of the mandible were exposed. A pre-auricular, s-shaped incision inferior to the zygomatic arch was used to expose the TMJ, and a subperiosteal connection was made with the previously prepared lateral side of the vertical ramus. An ELI-23 titanium cutting guide was screw-fixed to the vertical ramus to aid in performing the condylectomy. The joint space was then opened and the temporomandibular disc was removed. The condylectomy was then performed. The bony attachment of the lateral pterygoid muscle to the condyle was preserved in six sheep. In seven sheep, only the fibrocartilaginous part of the muscle insertion was unintentionally preserved. In two sheep, it was unclear whether either or both could be preserved. Compared with humans, it was difficult to keep the tendon inserted in the pterygoid fovea during dissection and removal of the rest of the condylar process. In our experience, in humans there is a larger bony insertion for the LPM to attach to the condyle. Sheep have a mostly fibrotic insertion into both the intra-articular disc and condyle. A PDS 0 suture (Ethicon, Sommverville, NJ, USA) was threaded through either the bony part of the enthesis or the fibrocartilaginous insertion. The fossa component was first placed using a dummy version and was fixed using five screws. Bone from the resected condyle was harvested, crushed, and mixed with fibrin sealant (Tisseel, Baxter, Deerfield, IL, USA). It was then manually pressed into the pterygoid fovea scaffold (Fig 4a, b). The ramal component was then fit in place while the PDS 0 was threaded through the subcondylar tunnel and then tied to the small hook as soon as the ramal component was fixed to the mandible (Fig 5). Using the suture to pull the bony enthesis to the bone in the scaffold proved difficult because the UHMWPE of the fossa component was interfering in a caudal direction. All UHMWPE parts were scalpel-reduced at the anteromedial side to facilitate routing the enthesis or tendon/fibrocartilaginous part of the disc.Nikolas de Meurechy NW.indd 185 05-06-2024 10:14