Clinical accuracy of waferless maxillary positioning using customized surgical guides and patient specific osteosynthesis in bimaxillary orthognathic surgery

Spontaneous Condyle-Like Development after Total Resection of Mandible Giant Osteochondroma: Case Report and a Follow-Up for Five Years

Osteochondroma manifests as a benign tumor that occurs as an abnormal bony development. This tumor is commonly asymptomatic and presents an exophytic outgrowth on bone surfaces, near synovial joints, a condition that invariably induces evident facial deformities. Treatment for this type of tumor usually involves a surgical approach promoting a total or partial resection of the affected anatomical area associated to prosthetic reconstruction of the bone area extracted. We present a case report about a giant mandibular condyle osteochondroma in a 37-year-old female patient. Her treatment involved a total condylectomy without immediate condylar reconstruction, which would be performed in a posterior surgical approach. During the patient's follow-up (every 6 months of post operation), a spontaneous and rudimentary condyle-like formation was observed. Because the stomatognathic function and facial harmony were satisfactory, we observed the condyle-like development for 5 years of follow-up. Also, because both the aesthetic aspect and functional evolution of the maxillary bone were considered satisfactory, no complementary reconstruction surgical treatment was required for the giant osteochondroma of the mandibular condyle.

Accuracy of 3D virtual surgical planning for maxillary positioning and orientation in orthognathic surgery

OBJECTIVE

This retrospective and observational study evaluated the accuracy of a 3D virtual surgical planning (VSP) for the maxillary positioning and orientation in patients undergoing bimaxillary orthognathic surgery, comparing the planned and postoperative outcomes.

SETTING AND SAMPLE POPULATION

Seventy consecutive patients of both sexes, who were submitted to bimaxillary orthognathic surgery between 2015 and 2019 were included in our study.

MATERIAL AND METHODS

The patients were evaluated by fusing preoperative planning and postoperative outcome using cone-beam computed tomography scan evaluation. Three-dimensional VSP and postoperative outcomes were compared by using three linear and three angular measurements. The main outcome interest was the difference between the VSP movement, and the surgical movement obtained. The success criterion adopted was a mean linear difference of <2 mm and a mean angular difference of <4°.

RESULTS

Results were analysed using a linear mixed model with fixed and random effects, at α = .05. No significant statistical differences were found for linear and angular measurements between the planned and postsurgical outcomes (P > .05). All overlapping points presented values within the range considered clinically irrelevant (<2 mm; <1°).

CONCLUSIONS

Three-dimensional VSP was executed with a high degree of accuracy. When comparing the planned and postsurgical outcomes, all overlapping points presented values within the range considered clinically irrelevant.

Accuracy of mandible-independent maxillary repositioning using pre-bent locking plates: a pilot study

The double splint method is considered the gold standard for maxillary repositioning, but the procedure is lengthy and prone to error. Recent splintless methods have shown high repositioning accuracy; however, high costs and technical demands make them inaccessible to many patients. Therefore, a new cost-effective method of mandible-independent maxillary repositioning using pre-bent locking plates is proposed. Plates are bent on maxillary models in the planned position prior to surgery. The locations of the plate holes are replicated during surgery using osteotomy guides made from thermoplastic resin sheets. Pre-bent plates are subsequently fitted onto the maxilla, and plate holes are properly set to reposition the maxilla. The purpose of this study was to evaluate the accuracy of this method for maxillary repositioning and the reproducibility of the plate holes. Fifteen orthognathic surgery patients were evaluated retrospectively by superimposing preoperative simulations over their postoperative computed tomography models. The median deviations in maxillary repositioning and plate hole positioning between the preoperative plan and postoperative results were 0.43mm (range 0-1.55mm) and 0.33mm (range 0-1.86mm), respectively. There was no significant correlation between these deviations, suggesting that the method presented here allows highly accurate and reliable mandible-independent maxillary repositioning.

Splintless orthognathic surgery in edentulous patients-a pilot study

The aim of this pilot study was to evaluate the accuracy and predictability of a splintless treatment protocol for edentulous patients undergoing orthognathic surgery in four consecutive cases. All operations were virtually planned, followed by computer-aided design of individual osteotomy guides and patient-specific fixation implants, which were three-dimensionally printed in titanium. In order to evaluate the discrepancy between the planned and the achieved postoperative result, the postoperative outcome was compared to the virtual treatment plan. Rotational and translational movement and discrepancies with the planned movements were quantified for the maxilla; the advancement was quantified for the mandible. For the maxilla, there was a mean translation discrepancy of 0.6mm. With regard to rotation, there was a mean discrepancy of 1.9°, 0.1°, and 0.4° for pitch, yaw, and roll, respectively. The mean discrepancy in translation of the mandible was 0.4mm. The results of this pilot study indicate that the splintless treatment protocol for orthognathic surgery in edentulous patients presented here is accurate and predictable.

The Use of Patient-Specific Implants in Oral and Maxillofacial Surgery

This article summarizes the current use of patient-specific implants in oral and maxillofacial surgery.

CAD/CAM splint and surgical navigation allows accurate maxillary segment positioning in Le Fort I osteotomy

Purpose

To evaluate the accuracy of the maxillary segment positioning method using a splint fabricated by computer-aided design/computer-aided manufacturing (CAD/CAM) and surgical navigation in patients who required two-jaw surgery.

Methods

Subjects were 35 patients requiring two-jaw surgery. A 3-dimensional (3D) skull model was prepared using cone-beam computed tomography (CBCT) data and dentition model scan data. Two-jaw surgery was simulated using this model, and a splint for maxillary positioning was fabricated by CAD/CAM. Using coordinate transformation software, the coordinate axis of surgical simulation data was merged with the navigation system, and data were imported to the navigation system. The maxillary segment was placed using the CAD/CAM splint, and consistency of the maxillary segment position with that planned by simulation was confirmed using the navigation system. CBCT taken at 4 weeks postoperatively and the prediction image fabricated using surgical simulation were superimposed. Predicted movement distances (PMD) at 6 arbitrary measurement points and actual movement distance (AMD) in surgery were measured. Differences of 3D measurements between the surgical simulation and postoperative results were evaluated.

Results

No significant differences were seen between PMD and AMD at most measurement points on the X and Y axes. Although significant differences between PMD and AMD were seen on the Z axis, no difference was evident between linear distance on the estimated image and postoperative CBCT image at most measurement points in 3D space. Mean error at measurement points between the PMD and AMD ranged from 0.57 mm to 0.78 mm on the X axis, 0.64 mm–1.03 mm on the Y axis, and 0.84 mm–0.90 mm in the Z axis.

Conclusion

Position of the maxillary segment moved by the CAD/CAM splint in Le Fort I osteotomy was almost consistent with the position established by simulation using the navigation system, confirming clinical accuracy.

The use of patient-specific implants in genioplasty and its clinical accuracy: a preliminary study

The purpose of this study was to assess the accuracy and clinical validation of patient-specific implants (PSI) in genioplasty. Fifteen patients with chin deformities were enrolled. Virtual planning was performed with the computer-aided surgical simulation method. The three-dimensional-printed titanium cutting guide and patient-specific plate were designed to guide the osteotomy and allow repositioning and fixation of the chin. The outcome was evaluated by comparing the plan with actual outcomes. All operations were successfully completed with PSIs. There was no difficulty in using patient-specific plates. The largest root-mean-square difference of the chin position was 0.69 mm in mediolateral translation and 2.01° in the yaw orientation. The results of the study indicated that the PSI technique was an accurate method of transferring the virtual plan to the operation field with great efficiency in genioplasty. A significant advantage of the PSI technique is that the patient-specific plate could simultaneously complete the repositioning and fixation of the chin. Intraoperative measurements and reposition guides were no longer required. Operative procedures were greatly simplified.

No differences in infections between patient-specific implants and conventional mini-plates in mandibular bilateral sagittal split osteotomy - Up to 3-year follow-up

The use of individually designed osteotomies, combined with individually manufactured osteosynthesis material, is rapidly becoming a standard for more challenging maxillofacial surgery. The benefits of patient-specific implants (PSI) in orthognathic surgery are clear in complex cases. PSIs can enhance precision and ease up the surgical protocol. We previously reported on the benefits of PSIs as reposition and fixation systems during Le Fort I osteotomy. The aim of this study was to evaluate a cohort of 28 patients, treated with bilateral sagittal split osteotomy (BSSO) and PSIs for fixation, with regard to healing for up to 3 years. A retrospective cohort of 48 patients with conventional mini-plate repositioned mandibles was also collected for statistical analysis. No statistically significant differences were found with regard to infection, soft tissue problems, or reoperations between these two groups.

Does Mandible-First Sequencing Increase Maxillary Surgical Accuracy in Bimaxillary Procedures?

PURPOSE

In bimaxillary procedures, it is important to know how the chosen sequence affects the surgical outcome. The purpose of this study was to explore whether the theoretical advantages of using the mandible-first procedure were supported by clinical data.

MATERIALS AND METHODS

The authors performed a retrospective investigation on a cohort compiled from 3 published retrospective studies. The sample was composed of patients treated at the Radboud University Nijmegen Medical Centre (Nijmegen, the Netherlands) from 2010 to 2014 and the Odense University Hospital (Odense, Denmark) from 2011 to 2015. The inclusion criterion was bimaxillary surgery without maxillary segmentation. The exclusion criterion was lack of a virtual surgical plan. The primary outcome variable was surgical accuracy, defined as the mean difference between the obtained outcome and the virtual surgical plan. The primary predictor variable was the comparison between mandible-first and maxilla-first sequencing. Secondary predictors were inferior maxillary repositioning and counterclockwise (CCW) rotation. The confounding variable was the virtually planned reposition. Results were analyzed by mixed-model regression encompassing all variables, followed by a detailed analysis of positive results using 2-sample t tests.

RESULTS

Overall, 145 patients were included for analysis (98 women; mean age, 28 years). Operating on the mandible first notably influenced maxillary positioning and placed the maxilla 1.5 mm posterior and with 1.4° of CCW rotation compared with virtual surgical planning. The interaction of surgical sequence with maxillary rotation showed similar surgical accuracy between maxilla-first surgery with clockwise rotation and mandible-first surgery with CCW rotation. Inferior maxillary repositioning resulted in the maxilla being placed 1.7 mm (maxilla-first sequence) and 2.0 mm (mandible-first sequence) posterior to the planned position.

CONCLUSION

Surgical accuracy was considerably influenced by sequencing in bimaxillary procedures. It remains important to know how the chosen sequence affects the surgical outcome so that the virtual surgical plan can be adjusted accordingly.

The accuracy and stability of the maxillary position after orthognathic surgery using a novel computer-aided surgical simulation system

Background

Many reports have been published on orthognathic surgery (OGS) using computer-aided surgical simulation (CASS). The purpose of this study was to evaluate the accuracy of the maxillary repositioning and the stability of the maxilla in patients who underwent OGS using a newly developed CASS program, a customized osteotomy guide, and a customized miniplate.

Methods

Thirteen patients who underwent OGS from 2015 to 2017 were included. All patients underwent a bimaxillary operation. First, a skull-dentition hybrid 3D image was rendered by merging the cone beam computed tomography (CBCT) images with the dentition scan file. After virtual surgery (VS) using the FaceGide® program, patient-customized osteotomy guides and miniplates were then fabricated and used in the actual operation. To compare the VS with the actual surgery and postoperative skeletal changes, each reference point marked on the image was compared before the operation (T0) and three days (T1), four months (T2), and a year (T3) after the operation, and with the VS (Tv). The differences between ΔTv (Tv-T0) and ΔT1 (T1-T0) were statistically compared using tooth-based reference points. The superimposed images of Tv and T1 were also investigated at eight bone-based reference points. The differences between the reference points of the bone surface were examined to evaluate the stability of the miniplate on the maxilla over time.

Results

None of the patients experienced complications. There were no significant differences between the reference points based on the cusp tip between ΔTv and ΔT1 (p > 0.01). Additionally, there were no significant differences between the Tv and T1 values of the bone surface (p > 0.01). The mean difference in the bone surface between Tv and T1 was 1.01 ± 0.3 mm. Regarding the stability of the miniplate, there were no significant differences between the groups. The difference in the bone surface between T1 and T3 was − 0.37 ± 0.29 mm.

Conclusions

VS was performed using the FaceGide® program, and customized materials produced based on the VS were applied in actual OGS. The maxilla was repositioned in almost the same manner as in the VSP plan, and the maxillary position remained stable for a year.

Interdisciplinary full-mouth rehabilitation for redefining esthetics, function, and orofacial harmony

OBJECTIVE

In severe congenital or acquired orofacial anomalies, both dental esthetics and function are usually compromised. In particular, the esthetic ideas of the final desired appearance may differ from patient to patient, as the human esthetic sensibility differs significantly. Especially in complex cases, digital technology today offers outstanding improvements and simplifications in craniomaxillofacial surgical and prosthetic treatments, leading to a wide range of planning and pretreatment options.

CLINICAL CONSIDERATIONS

This case report describes a patient-oriented interdisciplinary craniomaxillofacial surgical and prosthetic treatment with noninvasive tooth-colored splints, a Le Fort I osteotomy, and a full-mouth rehabilitation to meet the patient's demand for better function as well as orofacial esthetics and harmony.

CONCLUSIONS

By means of the digitally planned Le Fort I intervention and completion of the prosthetic rehabilitation, it was possible to optimize esthetics and facial harmony.

CLINICAL SIGNIFICANCE

In complex cases, digital technology today offers outstanding improvements and simplifications in craniomaxillofacial surgery and prosthetic treatments, leading to a wide range of planning and pretreatment options. Computer-aided design/computer-aided manufacturing technology enables the fabrication of tooth-colored flexible polycarbonate splints that offer a noninvasive, removable, functional, and esthetic solution. In intricate cases involving craniomaxillofacial anomalies, often together with necessary orofacial surgeries or prosthetic treatments due to moderate to severe tooth wear, such digital preprosthetic treatment and planning options represent an important enhancement with more predictable results.

[CAD/CAM Revolution in Craniofacial Reconstruction]

CAD/CAM Revolution in Craniofacial Reconstruction Abstract. The face is an important part of the personality and at the same time fulfils a variety of tasks. Aesthetics and function form a unique unit. The formation of the field of oral and maxillofacial surgery began in the first decades of the last century. It includes the prevention, diagnosis, therapy and rehabilitation of diseases, injuries, malformations and changes of the complex structures of the face, oral cavity, jaw and teeth. In the meantime, oral and maxillofacial surgery has arrived in the 21st century. Today's oral and maxillofacial surgery is a link between medicine and dentistry and a protagonist in the implementation of digital workflows in clinical care. Individual solutions with patient-specific implants are the rule, computer-assisted techniques support the surgeon in the planning and performing of surgical procedures. This article intends to give you an insight into how our patients benefit from advanced technologies.

Toward a higher accuracy in orthognathic surgery by using intraoperative computer navigation, 3D surgical guides, and/or customized osteosynthesis plates: A systematic review

The aim of this study was to systematically review the accuracy of intraoperative computer navigation, three-dimensional surgical guides and customized osteosynthesis plates for the transfer of the virtual surgical plan to the patient in orthognathic surgery. A systematic review of the currently available publications was performed in databases MEDLINE, Embase, and Cochrane Library, using a PICOS search strategy, and reported according to PRISMA. The initial search yielded 3050 articles. In total, 16 studies were included for final quantitative analyses. The results of individual studies demonstrated a comparable accuracy in the transfer of planned surgical displacement of the jaws. A large variability was found with regard to the method of accuracy assessment and reported outcomes. The findings of this review show that these modern techniques have the potential to replace interocclusal splints in routine clinical practice in the future. We recommend that authors presenting new data on the accuracy of a technique should choose the method of accuracy assessment meticulously, acquiring postoperative imaging as soon as possible after surgery. They should report as much as possible, summarizing values or, ideally, even the raw data of the accuracy assessment in order to allow comparison with other techniques in a meta-analysis.

Patient-Specific Printed Plates Improve Surgical Accuracy In Vitro

PURPOSE

It remains unclear to what extent patient-specific printed plates can improve surgical outcomes in orthognathic procedures. This study aimed to quantify the surgical accuracy of patient-specific printed plates in vitro and to compare the results with patients' actual surgical outcomes.

PATIENTS AND METHODS

This in vitro study enrolled 20 postoperative orthognathic surgical patients, all treated with inferior maxillary repositioning. The preoperative midfaces were re-created in a 3-dimensionally printed model. The osteotomy and screw holes were placed at prespecified positions using a 3-dimensional guide. The dental segment was repositioned by means of the patient-specific plates. The primary outcome was the mean reposition at 3 dental reference points. The primary predictor variable was the obtained surgical reposition in vitro compared with the virtual surgical plan. Confounding variables were gender, age, occlusion, and bimaxillary surgery. The secondary outcome was surgical accuracy, and the secondary predictor was the in vitro outcomes versus the patients' surgical outcomes. Surgical accuracy was defined as the difference between the obtained reposition and the virtual surgical plan on a continuous scale. The differences were recorded in 3 dimensions according to the positive value of the 3 axes: right, anterior, and posterior. The results were analyzed using mixed-model regression and 1-sample t tests.

RESULTS

In the 20 patients (age, 18 to 64 years; 40% of patients were women), the mean planned reposition was 2.9 mm anterior and 1.8 mm inferior. In all models, the osteotomy edge was rounded off to position the plate in the predetermined position. Overall, the maxilla was positioned 0.5 mm anterior and 0.3 mm inferior to the planned position using patient-specific plates.

CONCLUSIONS

The patient-specific plates positioned the maxilla in close approximation to the planned position without surgically relevant differences. The osteotomy edge must be carefully inspected for interference with the patient-specific plates to avoid displacement of the planned maxillary repositioning.