Abstract
Minimally invasive orthognathic surgery (MIOS) represents a significant paradigm shift in oral and maxillofacial surgery. The impact of MIOS on the temporomandibular joint (TMJ) remains a topic of debate. This case report aims to evaluate changes in mandibular condylar volume in the TMJ following MIOS and establish a foundation for further research in this area.
1
Introduction
Traditional orthognathic surgery (OS) typically involves Bilateral Sagittal Ramus Osteotomy (BSSO) to reposition the mandible, affecting condylar volume and positioning within the TMJ. Such changes can be considered physiological or pathological. Condylar remodelling is an adaptive physiological process that modifies TMJ structure based on mechanical forces and the adaptive capacity of the TMJ. When this process exceeds physiological limits, bone resorption can outweigh formation, leading to condylar resorption [ , ] (see Fig. 1 )
In the past two decades, minimally invasive surgery, as introduced by Hunter, has transformed surgical practices, focusing on reducing the sequelae of traditional procedures [ ]. Minimally invasive orthognathic surgery (MIOS) employs smaller incisions and tunneling techniques to minimize soft tissue disruption, while incorporating osteotomies described by Obwegeser and Trauner [ ], in contrast to the Dal Pont osteotomy [ ] used in OS.
Although condylar volumetric changes following OS have been extensively studied [ ] to our knowledge, there is limited information on condylar changes following MIOS. This case report aims to evaluate the changes in condylar volume following MIOS.
2
Materials and methods
A cone beam computed tomography (CBCT) of a female patient with a class lll dentofacial deformity who underwent bimaxillary MIOS for setback positioning of the mandible was taken 1 week prior to surgery and another one 6 months after surgery. We used ITK-SNAP 4.0.2 software to segment each condyle and to evaluate their volume (open-source software available at http://www.itksnap.org/pmwiki/pmwiki.php?n=Downloads.SNAP4 ) in DICOM format. Semi-automated segmentation of the 3D model was established in ‘region competition’ mode and assisted with manual segmentation when necessary in each and every CT slice, and the volume of each condyle was registered in cubic millimeters (mm 3 ).
3
Results
After the 6-month window, the patient was evaluated concluding stabilization of condylar volume changes and optimal clinical results with no complications after MIOS. Following semi-automated segmentation of condyles of both preoperative and postoperative CBCT scans, a decrease in condylar volume was observed: 4.3 % in the right condyle and 2.09 % in the left condyle ( Table 1 .)
