Surgical Guides and Prebent Titanium Improve the Planning for the Treatment of Dentofacial Deformities Secondary to Condylar Osteochondroma

Application of mixed reality bone registration and positioning technology in orthognathic surgery

In orthognathic surgery, the positioning of the bone segments has a significant impact on the postoperative occlusion, temporomandibular joint, and facial morphology. Within the field of digital surgical planning, the placement of these bone segments represents the transfer of the virtual surgical plan (VSP). Computer-aided design/computer-aided manufacturing-assisted bone segment positioning devices have demonstrated high localization accuracy, but they require complex guide systems. The mixed reality technique described here, based on pre-bent titanium plates, facilitates the transfer of the VSP without the need for complex guide systems and enables dynamic intraoperative navigation under direct vision. This technique could replace 3D-printed tooth-supported guide plates for surgical navigation. The observed registration error was approximately 1 mm and the registration delay was 0.3 s. Application of this technique in the clinical case demonstrated good accuracy, and postoperative stability was achieved.

CAD/CAM surgical guides and pre-bent distractors: Enhancing precision in MDO for severe dentofacial deformities secondary to TMJ ankylosis

BACKGROUND

This study aimed to compare the different outcomes of mandibular distraction osteogenesis (MDO) using computer-aided design and manufacturing (CAD/CAM) surgical guides accompanied by pre-bent distractors versus CAD/CAM surgical guides with commercial distractors.

METHODS

Twenty-eight patients with severe dentofacial deformities secondary to unilateral temporomandibular joint ankylosis (TMJA) were retrospectively enrolled. Ten parameters associated with MDO were measured preoperatively, virtually, and postoperatively. The hard-tissue digital model was reconstructed using Mimics Research 17.0, and imaging data were collected and analyzed using Freeform Plus software 12.0, Geomagic Studio 12.0, and IBM SPSS Version 20.0.

RESULTS

Twenty-eight patients underwent MDO with subsequent adjunctive surgery and were evaluated. Thirteen patients underwent CAD/CAM surgical guides with pre-bent distractors (group A), while fifteen underwent CAD/CAM guides with commercial distractors (group B). Both techniques achieved optimal occlusion and satisfactory appearance. Statistical analysis showed group A demonstrated a more accurate control of vector direction during MDO compared to group B (p < 0.05). Additionally, group A also exhibited a shorter subsequent treatment duration and less relapse compared to group B (p < 0.05).

CONCLUSIONS

CAD/CAM surgical guides with pre-bent distractors can significantly enhance surgical accuracy in controlling the vector direction of MDO for correcting dentofacial deformities secondary to TMJA, leading to a reduction in subsequent treatment duration and occurrence.

Total Joint Replacement for Immediate Reconstruction following Ablative Surgery for Primary Tumors of the Temporo-Mandibular Joint

Temporomandibular joint (TMJ) tumors are rare and difficult to diagnose. The purpose of this retrospective study was to evaluate the clinicopathologic characteristics of twenty-one patients with primary TMJ tumors between 2010 and 2019 and to analyze the surgical outcome and morbidity after ablative surgery and TMJ replacement. This case series confirmed the difficulty of diagnosis and reaffirmed the need for early recognition and management of TMJ tumors. There were no pathognomonic findings associated with TMJ tumors, although single or multiple radiopaque or radiolucent areas were observed on plain or panoramic radiographs. Occasionally, bone resorption or mottled densities caused by pathologic calcification and ossification were seen. Computed tomography and magnetic resonance imaging played an important role in the diagnosis. In our study, the distribution of histologic types of TMJ tumors was quite different from that of other joint tumors. The recommended treatment was surgical intervention by ablation of the joint and TMJ replacement. The results of this retrospective study support the surgical exeresis and replacement with TMJ stock and custom-made prostheses and show that the approach is efficacious and safe, reduces pain and improves mandibular movements, with few complications.

Clinical Application of Individualized 3D-Printed Templates in the Treatment of Condylar Osteochondroma

BACKGROUND

Osteochondroma (OC) is one of the most common benign tumors of the long bones, but it rarely occurs in the maxillofacial skeleton. However, mandibular condylar OC often leads to severe facial deformity in affected patients, including facial asymmetry, deviation of the chin, and malocclusion. This study aimed to explore the clinical application of individualized 3D-printed templates to accurately and effectively treat condylar OC.

METHODS

A total of 8 patients with mandibular condylar OC were treated from July 2015 to August 2021. The enrolled patients (5 women and 3 men) had a median age of 27 years (range: 21-32 years). All patients exhibited symptoms of facial asymmetry and occlusal disorders preoperatively. The digital software used to virtually design the process consisted of three-dimensional reconstruction, 3D-cephalometry analysis, virtual surgery, individualized templates, and postoperative facial soft-tissue prediction. A set of 3D-printed templates (DOS and DOT) were used in all cases to stabilize the occlusion and guide the osteotomy. Then, pre- and post-operative complications, mouth opening, clinical signs, and the accuracy of the CT imaging analysis were all evaluated. All the measurement data were presented as means ± SD; Bonferroni and Tamhane T2 multiple comparison tests were used to examine the differences between the groups.

RESULTS

All patients healed uneventfully. None of the patients exhibited facial nerve injury at follow-up. In comparing the condylar segments with T0p and T1, the average deviation of the condylar segments was 0.5796 mm, indicating that the post-operative reconstructed condyles showed a high degree of similarity to the reconstruction results of the virtual surgical plan.

CONCLUSIONS

Individualized 3D-printed templates simplified surgical procedures and improved surgical accuracy, proving to be an effective method for the treatment of patients with slight asymmetric deformities secondary to condylar OC.