Surgery · Medical Literature
Precision of virtual surgical planning employing screw-holes locator and patient-specific implants versus conventional plate osteosynthesis for parasymphyseal mandibular fracture: a double-blinded randomized control trial.
Abstract
Conventional plate osteosynthesis is the corner stone for management of displaced parasymphyseal mandibular fractures that necessitate open reduction and internal fixation (ORIF). Yet, the conventional workflow is labor-intensive, time consuming and limited by variable reduction accuracy as it relies solely on surgeon experience. Recently, various novel computer-guided techniques have been introduced for mandibular fracture repair, hiring surgical guides of diverse designs and strategies. These techniques served as a substitute for the conventional treatment modalities, offering improved precision, speed and reproducibility. Therefore, this randomized controlled trial (RCT) compares the overall precision of this distinct complete computer-guided virtual surgical planning (VSP) protocol as a whole, employing screw-holes locator and custom-made plates versus the conventional workflow for parasymphyseal mandibular fracture repair. Twenty-six cases presented with uncomminuted parasymphyseal mandibular fracture were enrolled and randomized into two groups. The interventional group underwent ORIF utilizing a screw-hole locator and custom-made plates, while the control group utilized ready-made mini-plates for ORIF. In both groups, virtual surgical planning of the fractured mandible was accomplished, creating a virtual reduced model by Mimics software aided by preoperative computer tomography (CT) scan. Then, three-dimensional model derived from the postoperative CT scan was superimposed onto the VSP reduced model. Linear deviations between predefined dental and bony landmarks to established anatomical planes were measured and underwent statistical analysis. The actual postoperative mandibular model in the computer-guided group demonstrated negligible deviation from the VSP model. While the conventional group revealed considerably greater deviation. The average deviation of the bony landmarks was 0.044 ± 0.14 mm for the intervention group versus 0.69 ± 0.5 mm for the control group (p < 0.001). The average deviation of the dental landmarks was 0.04 ± 0.13 mm for the intervention group versus 0.47 ± 0.33 mm for the control group (p < 0.001). The average surgical time of the intervention group was 1.46 ± 0.18 h versus 1.80 ± 0.34 h for the control group (p = 0.004), with the intergroup difference being statistically significant. The integration of screw-holes locator and patient-specific implants (PSI) have improved anatomical reduction precision, facilitated reestablishment of the patient's native occlusion and ensured more standardized reproducible outcomes, especially beneficial for less experienced surgeons. The study is a randomized control trial, registered at ClinicalTrials.gov Protocol Registration and Results System Receipt, NCT05647460, Data: 2022-12-05.
Clinical relevance
Parasymphyseal mandibular fractures requiring ORIF represent a technically demanding subset of facial trauma surgery where reduction accuracy is heavily operator-dependent under conventional workflows. This RCT addresses the clinical gap between surgeon experience and reproducible anatomical reduction by evaluating a complete computer-guided VSP protocol using patient-specific implants (PSI) and screw-hole locators. The findings are immediately relevant to oral-maxillofacial surgeons seeking to standardize outcomes, reduce operative time, and expand access to high-precision fracture repair beyond high-volume expert centers.
Key findings
1. Bony landmark deviation was significantly lower in the VSP/PSI group versus conventional plating: 0.044 ± 0.14 mm vs. 0.69 ± 0.5 mm (p < 0.001), representing an approximately 15-fold improvement in bony reduction accuracy. 2. Dental landmark deviation was similarly superior in the intervention group: 0.04 ± 0.13 mm vs. 0.47 ± 0.33 mm (p < 0.001), reflecting near-perfect restoration of native occlusal relationships. 3. Mean operative time was significantly shorter in the computer-guided group: 1.46 ± 0.18 hours vs. 1.80 ± 0.34 hours for conventional plating (p = 0.004), a mean reduction of approximately 21 minutes. 4. The VSP/PSI protocol achieved negligible deviation from the preoperative virtual reduced model on postoperative CT superimposition, whereas the conventional group demonstrated considerably greater and more variable deviation. 5. The study enrolled 26 patients with uncomminuted parasymphyseal mandibular fractures in a double-blinded RCT design, with virtual planning performed using Mimics software and outcome assessment by 3D CT superimposition onto the VSP model. 6. The magnitude of reduction error in the conventional group (up to ~0.69 mm at bony landmarks and ~0.47 mm at dental landmarks) was clinically meaningful given the precision required for occlusal rehabilitation and condylar positioning in the parasymphyseal region.
Practice implications
Oral-maxillofacial surgeons should consider integrating VSP with PSI and screw-hole locators for ORIF of displaced parasymphyseal mandibular fractures, particularly in cases where precise occlusal restoration is critical or when performed by surgeons with limited fracture volume experience. Patient selection should prioritize uncomminuted fracture patterns amenable to virtual reduction modeling, and preoperative CT acquisition must be of sufficient resolution to support accurate Mimics-based virtual planning and custom implant fabrication. Adoption of this workflow may reduce intraoperative decision-making burden, shorten operative times, and improve reproducibility of anatomical reduction across surgical teams of varying experience levels.