Advancing Temporomandibular Joint Reconstruction: A Cadaveric Study on the Design of the Fourth Chondrocostal Joint Flap.

[BACKGROUND] The free fibula flap is the gold standard for reconstructing mandibular defects caused by trauma, tumors, dysplastic diseases, osteoradionecrosis, and atrophy. However, it has not yet been shown to be the ideal method for condylar reconstruction. This anatomical study proposes a surgically pragmatic approach to temporomandibular joint and condylar reconstruction by defining the vascularity of the chondrocostal joint.

[METHODS] One fresh frozen and six fixed cadavers were dissected to assess the suitability of the 4th rib for the planned procedure. Bilateral internal thoracic vessels and branches surrounding chondrocostal joints were identified. The 4th chondrocostal joint flap was dissected with care to preserve the joint surface and perichondral vascularity. Digital calipers were used for precise measurements of maximal flap and pedicle length. The vascular anatomy was further explored in a fresh frozen cadaver through fluoroscopic imaging by radiopaque latex injection. The flap's suitability for temporomandibular joint reconstruction was tested by surgically removing the original temporomandibular joint from the cadaveric skull and positioning the chondrocostal joint flap in the resultant defect.

[RESULTS] The dominant pedicle to the fourth chondrocostal joint was shown to be the perforators of the internal thoracic vessels. The mean pedicle length was 4.7 cm, which was sufficient to reach recipient vessels in the neck. The compatibility between the fourth chondrocostal joint and the glenoid fossa was confirmed.

[CONCLUSION] This study demonstrates that the fourth chondrocostal joint flap is a promising free flap for temporomandibular joint and condylar reconstruction. It offers ideal pedicle positioning, length, and vascular size match at the anastomosis, making it a suitable technique for reconstructing the challenging temporomandibular region. This approach adds a new option to the reconstructive surgeon's armamentarium, addressing previous limitations in condylar reconstruction.