Use of modified 3D digital surgical guides in the treatment of complex mandibular fractures

Office-Based Digital Workflow for Managing Old Mandibular Fracture Malunion: Use of Short-Segment Drilling and Osteotomy Guides With Predictive Holes

Treating old mandibular fractures with malunion is challenging due to the need for osteotomy and interference between bone segments, complicating occlusal restoration. This technical note introduces a novel office-based digital workflow utilizing surgical guides. Preoperative computed tomography (CT) data were imported into MIMICS software for virtual surgical planning to precisely realign bone fragments based on anatomical and occlusal relationships. A pre-bent reconstruction plate was adapted to a 3-dimensional-printed mandible model, and cone beam CT scans captured detailed screw path data. This information was used in 3-matic software to design short-segment drilling guides (SSDGs), and osteotomy guides with predictive holes. These guides facilitated accurate bone osteotomy and realignment during surgery. This workflow addresses the limitations of previous SSDGs, offering a reliable solution for managing malunion in old mandibular fractures. The approach reduces surgical complexity, enhances precision, and streamlines treatment, providing an innovative method for challenging mandibular fractures.

A Proof of Concept: Optimized Jawbone-Reduction Model for Mandibular Fracture Surgery

Previous research on computer-assisted jawbone reduction for mandibular fracture surgery has only focused on the relationship between fractured sections disregarding proper dental occlusion with the maxilla. To overcome malocclusion caused by overlooking dental articulation, this study aims to provide a model for jawbone reduction based on dental occlusion. After dental landmarks and fracture sectional features are extracted, the maxilla and two mandible segments are aligned first using the extracted dental landmarks. A swarm-based optimization is subsequently performed by simultaneously observing the fracture section fitting and the dental occlusion condition. The proposed method was evaluated using jawbone data of 12 subjects with simulated and real mandibular fractures. Results showed that the optimized model achieved both accurate jawbone reduction and desired dental occlusion, which may not be possible by existing methods.

Streamlining complex mandibular fracture treatment: Integration of virtual surgical planning and short-segment drilling guides

This study aimed to evaluate the feasibility and accuracy of a combined virtual surgical planning (VPS) and short-segment drilling guides (SSDGs) workflow for the treatment of complex mandibular fractures. Consecutive patients with complex mandibular fractures underwent treatment using the VPS and SSDGs workflow from August 2020 to April 2022. Various mandibular landmarks were compared between the preoperative virtual surgical plan and postoperative data, including condylar distance (CoD), mandibular angle width (GoL-GoR), GoMeGo angle (∠GoL-Me-GoR), the difference in mandibular angles between the left and right sides (Δ∠Co-Go-Me), and the difference in length between the left and right mandibular body (ΔGo-Me). Additionally, preoperative preparation time and surgical duration were retrospectively analyzed and compared to conventional surgery. All 14 consecutive patients with complex mandibular fractures achieved successful reduction using the VPS and SSDGs workflow. Three-dimensional comparison revealed a mean deviation distance of 0.91 ± 0.50 mm and a root-mean-square deviation of 1.75 ± 0.47 mm between the preoperative designed mandible model and the postoperative mandible model. The percentage of points with deviation distances less than 2 mm, 1 mm, and 0.5 mm between preoperative and postoperative models were 78.47 ± 8.87 %, 60.02 ± 14.28 %, and 38.64 ± 15.48 %, respectively. There were no significant differences observed in CoD, GoL-GoR, ∠GoL-Me-GoR, Δ∠Co-Go-Me, and ΔGo-Me between preoperative virtual surgical planning and postoperative measurements. Furthermore, no significant differences were found in the injury-to-surgery interval, admission-to-surgery interval, and surgical duration between the workflow and conventional surgery. The combined VPS and SSDGs workflow proved to be an accurate and feasible method for treating complex mandibular fractures. It offers advantages such as minimal preoperative preparation time and the ability to precise transfer screw positions of the pre-bent reconstruction plate during surgery. This approach is particularly suitable for managing complex mandibular fractures.

Patient-specific plates for facial fracture surgery: A retrospective case series

OBJECTIVES

Surgeons often encounter challenges when treating maxillofacial fractures using conventional methods that involve trimming or bending ready-made titanium plates for open reduction and internal fixation (ORIF) since it can be time-consuming, imprecise, and inconvenient. This retrospective case series aimed to introduce a novel bone reduction method that utilizes virtual planning, patient-specific surgical guides, and titanium plates.

METHODS

Seven patients with mandibular symphysis or subcondylar fractures resulting from facial trauma underwent cone-beam computed tomography (CBCT) or facial CT scans, and their medical histories were documented. Virtual surgery was conducted based on three-dimensional (3D) stereolithography images derived from CT scans using the FaceGide software (MegaGen, Daegu, Korea). ORIF was performed using patient-specific surgical guides and plates that were designed, printed, and milled. Radiographic, clinical, and occlusal evaluations were conducted at two weeks and six weeks postoperatively. Subsequently, 3D images from virtual surgery and postoperative CT scans were compared.

RESULTS

The comparison of 3D virtual surgery and postoperative images revealed minimal surface differences of less than 1 mm. T-scan evaluations indicated that there were no statistically significant differences between the two- and six-week postoperative assessments. Favorable clinical outcomes were observed.

CONCLUSION

This novel method demonstrated stable outcomes in terms of occlusion and healing, with no notable complications. Consequently, this approach may serve as a viable alternative to conventional methods.

CLINICAL SIGNIFICANCE

Facial fracture surgery that utilizes patient-specific surgical guides and plates within a digital workflow can facilitate meticulous surgical planning, reducing the risk of complications and minimizing operation time.

Classification of unusual fracture patterns of the mandible: A retrospective study

The aim of this study is to devise and summarize a classification of fracture patterns involving multiple anatomical sites of the mandible. A retrospective study was conducted by reviewing clinical case records, imaging records, and the surgical management of patients presenting with mandibular fracture. Demographic data were collected and causes of the fractures were studied. Following radiological evaluations based on the courses of fracture lines, these fractures were categorized into three components: horizontal (H), vertical (V), and sagittal (S). In case of horizontal components, the mandibular canal was used as a reference. For vertical components, the fracture lines were classified according to where they terminated. With sagittal components, the direction of the bicortical split at the base of mandible was used as a reference. Out of a total of 893 mandibular trauma patients, 30 unusual fractures were identified (21 in males and nine in females), which do not fit into existing classifications. These were mainly due to road traffic accidents. Horizontal components of fractures were classified as H-I, H-II, and H-III, and vertical components as V-I, V-II, and V-III. For sagittal components, two types were identified - S-I and S-II - resulting in a bicortical split of the mandible. This classification is proposed to help understanding the complex fractures and to allow standardized communication among clinicians. Moreover, it is designed in such a way that aids in the choice of fixation technique. Further studies are needed to establish standardized treatment algorithms for efficient management of these unusual fractures.

Application of optimized three-dimensional digital surgical guide plates for complex midfacial fractures

INTRODUCTION

The treatment of midfacial fractures is always difficult. The purpose of this study was to verify whether optimized three-dimensional (3D) digital surgical guide plates combined with preformed titanium plates improved the treatment effect in complex midfacial fractures.

PATIENTS AND METHODS

Twenty-six patients with complex midfacial fractures were recruited and randomized into three groups: ten for Group A, eight for Group B, and eight for Group C. Group A was treated with a combination of preformed titanium plates and optimized 3D digital surgical guide plates. Group B was treated with preformed titanium plates only. Group C was treated conventionally. Clinical effects, patient-reported outcome measures (PROMs), midfacial contour, facial symmetry, surgical accuracy, △orbital volume (the absolute value of the bilateral orbital volume difference), and maximum deviation were evaluated in each of the three groups.

RESULTS

Group A had the best postoperative clinical effects and patient-reported outcomes. Significant improvements in midfacial contour (L1[0.72±0.29 mm, P = 0.001], L2[1.04±0.46 mm, P < 0.001]), facial symmetry (S1[0.71±0.30 mm, P < 0.001], S2[0.96±0.58 mm, P < 0.001], S3[0.86±0.40 mm, P < 0.001], S5[0.81±0.16 mm, P = 0.003], S8[0.95±0.30 mm, P < 0.001], S9[1.03±0.38 mm, P < 0.001], S11[0.64±0.46 mm, P < 0.001]) and surgical accuracy (M1[R, 0.82±0.31 mm, P < 0.001], M2[R, 0.87±0.44 mm, P < 0.001], M3[L, 0.88±0.22 mm, P = 0.004], M3[R, 1.06±0.31 mm, P = 0.003], M4[L, 0.96±0.45 mm, P = 0.008], M4[R, 1.11±0.57 mm, P = 0.003], M5[R, 0.76±0.26 mm, P < 0.001], M6[L, 1.00±0.46 mm, P = 0.003], M6[R, 1.00±0.58 mm, P = 0.001], M7[0.87±0.53 mm, P = 0.001], M8[R, 0.91±0.53 mm, P < 0.001], M9[R, 0.81±0.32 mm, P = 0.010], M10[R, 1.19±0.42 mm, P = 0.009], M11[L, 0.85±0.51 mm, P = 0.021], M11[R, 0.96±0.49 mm, P = 0.003]) were found in Group A compared with the other two groups. The results of △orbital volume and maximum deviation analysis showed an ideal surgical treatment effect in Group A.

CONCLUSION

Optimized 3D digital guide plates can accurately locate preformed titanium plates and effectively improve the treatment effect in complex midfacial fractures.

Short-Segment Drilling Guides for the Management Comminuted Mandibular Fractures

ABSTRACT

Treatment of a severely comminuted mandibular fracture is challenging. This technical note describes a novel office-based workflow, combining virtual surgery planning with short-segment drilling guides. The authors reduced the comminuted mandibular fractures via virtual surgery planning. Then, the reconstructed mandible model was printed using an in-house 3D printer. Next, the reconstruction plate was preformed according to the shape of the mandibular model surface, and the position of the screw hole in the mandibular surface was determined. Finally, hand-made short-segment drilling guides for screw position transfer were fabricated with temporary resin. During the operation, the authors reset the guides for the drill to make screw holes as planned. After the hole was drilled, the pre-bent plate was applied to the mandible. The fracture was expected to be reduced, when tightening the screws. In our workflow, by using short and simple operative procedures, the authors were able to achieve precise reduction and reduce the operation time.