Significance of Medio-Lateral Depth (MLD) in TMJ ankylosis surgery - A newer severity index based surgical outcomes study

Introduction Temporomandibular joint (TMJ) ankylosis is a debilitating disorder caused by fibrous or osseous fusion of the joint components, significantly restricting mandibular mobility. In children’s, TMJ ankylosis disrupts normal facial growth, resulting in persistent functional and aesthetic challenges. The Medio-Lateral Depth (MLD) of the bony ankylotic mass is a vital yet underexplored factor influencing the complexity of surgery. Increased depth and density of the ankylotic block exacerbate surgical difficulty and involved postoperative complications. This study aims to assess the role of the Medio-Lateral Depth (MLD) of the bony ankylotic mass in influencing surgical outcomes and specific indicators of morbidity. Materials and Methodology This study was designed as a prospective single centre, cohort study. The medio-lateral depth (MLD) was measured pre-operatively by CT scan and intra operatively by depth gauge scale. Intra operative depth was first correlated to the MLD on CT scan to check its validity. also, other post operative variables outcomes were correlated to the MLD. Results 34 patients were included in the study. MLD measured preoperatively from CT scan and intraoperatively measured depth has a mean value of 3.16cm and 2.93cm respectively. A strong correlation (Spearman R = 0.9637, p < 0.0001) was observed between depth in CT and depth measured intra-op. Significant correlations were also found between Depth intra-op and drain collection on POD-1 (R = 0.5793, p = 0.0003). The cases in this series were classified into mild, moderate and severe cases depending on the variability of MLD measured preoperatively by CT scan and Intra operative Depth therefore nomenclated as Venkatesh MLD severity index (VSI) for ankylotic mass. Mild- <2.5cm, Moderate − 2.5cm to 4.0cm and Severe > = 4.0cm. Conclusion Increasing MLD in ankylotic masses is strongly associated with surgical complexity, intraoperative challenges, and postoperative recovery. Depth remains a pivotal prognostic parameter, influencing operative time, blood loss, and recovery trajectories. Preoperative imaging, meticulous planning, and depth-informed surgical training are critical to optimizing outcomes.