Improvement in accuracy of maxillary repositioning of Le Fort I osteotomy with Orthopilot™ Navigation System: evaluation of 30 patients.

Traditional model surgery with facebow transfer is not very accurate. We aimed to demonstrate that the Orthopilot™ Navigation System improves the accuracy of maxillary repositioning during Le Fort I osteotomy. Thirty patients underwent Le Fort I osteotomy alone or associated to sagittal split osteotomy. The maxilla positioning was done in two phases. First, the maxilla was positioned with the traditional occlusal splint, the position ("without Orthopilot™") was recorded by the Orthopilot™. In the second phase, the Orthopilot™ was used to improve positioning; and the final position ("with Orthopilot™") was recorded, after osteosynthesis. Positioning data were compared with planned data. Positioning data with and without the Orthopilot™ were also compared. Accuracy was classified in distinct classes with three major criteria (conformity, non-conformity, failure) according to the discrepancies. Conformity rate was significantly greater with the Orthopilot™ (2 without the Orthopilot™ compared with 8 with the Orthopilot™; p=0.01). The failure rate was significantly lower with the Orthopilot™ (18 without Orthopilot™ compared with 7 with the Orthopilot™; p=0.002). Dispersions of discrepancies were usually lower in all directions with the Orthopilot™. Navigation reduced the risk of discrepancy without cancelling it, especially when large movements are planned. The Orthopilot™ therefore improved the accuracy of traditional occlusal splint during Le Fort I osteotomy.

Quantification of the inaccuracy of conventional articulator model surgery in Le Fort 1 osteotomy: evaluation of 30 patients controlled by the Orthopilot® navigation system.

Occlusal splints are commonly used to position the maxilla during traditional orthognathic surgery. We aimed to quantify the inaccuracy of the maxillary positioning (in three dimensions) in traditional model surgery with the Orthopilot® navigation system. Thirty Le Fort I osteotomies were made using a standard technique. The position of the maxilla was recorded by the navigation system and defined by three values of translation and three of rotation. The recorded data were compared with the planned data. The accuracy of positioning was classified in distinct classes with three major criteria (conformity, non-conformity, and failure) according to the discrepancy. The positioning of the maxilla was in conformity with operative planning in 3/30 of our Le Fort I osteotomies (95% CI 2% to 27%) and in failure in 22/30 (95% CI 54% to 88%). The dispersion of the discrepancy was more important in the sagittal plane, particularly for the sagittal rotation and for the back-front translation, which reflected greater inaccuracy in this plan. The frontal orientation of the maxilla was better controlled. The risk of maxillary malposition was proportional to the planned maxillary advancement.

Learning condyle repositioning during orthognathic surgery with a surgical navigation system.

Condyle repositioning during bilateral sagittal splint osteotomy (BSSO) is a challenging step for the inexperienced surgeon. We aimed to demonstrate the benefit of navigation for learning the condyle repositioning. We treated 100 patients who underwent a BSSO. A trainee performed the condyle repositioning of one side in two phases. In the first one, the trainee positioned without watching the screen of the Orthopilot Navigation system (ONS). In the second one, the trainee could use the ONS to replace the condyle. Heuristic, anatomical and functional scores of each phase were recorded. Heuristic (17% vs. 75%; p<0.0001), anatomical (35% vs. 86%; p<0.0001) and functional (14% vs. 56%; p<0.0001) scores were significantly greater with the ONS. The ONS is a promising and original intraoperative learning tool for the repositioning of the condyle during BSSO.