Accuracy of maxillary repositioning by computer-aided orthognathic surgery in patients with normal temporomandibular joints

Feasibility of simultaneous TMJ arthroscopy in ADDwoR patients undergoing orthognathic surgery for jaw deformity

This study evaluated the feasibility of simultaneous temporomandibular joint (TMJ) arthroscopy and orthognathic surgery as a new treatment strategy for anterior disc displacement without reduction (ADDwoR) patients with severe jaw deformities. Twelve ADDwoR patients with facial deformities who underwent arthroscopy and orthognathic surgery between September 2015 and December 2019 were retrospectively evaluated. Pre- and postoperative maximum incisal opening (MIO) and joint pain were recorded. Computed tomography (CT) and three-dimensional cephalometric analysis were performed at 3 (T1) and ≥6 (T2) months postoperatively. Magnetic resonance imaging (MRI) of the TMJ was performed before, ≤7 days after and ≥6 months after surgery. The lateral profile radiological findings, the symmetry of the maxilla and mandible, and the MRI measurements were compared. Anterior disc displacement did not recur, and the maximum incisal opening (MIO) increased from 27.4 mm to 32.7 mm after surgery (p < 0.05). No significant differences were found in the lateral profile, symmetry indices or condylar height via MRI between T1 and T2. Joint morphology and the position of both the maxilla and mandible remained stable during postoperative follow-up, while joint symptoms were markedly relieved and facial appearance was noticeably improved. Combined arthroscopy and orthognathic surgery is effective and recommended for ADDwoR patients with jaw deformities.

Evaluation of the accuracy of virtual planning in bimaxillary orthognathic surgery: Systematic review

The purpose of this research was to evaluate the accuracy of virtual planning in bimaxillary orthognathic surgery in bone by comparing the mean linear and angular measurements of the surgical plan with the actual surgical result. Electronic databases, MEDLINE via PubMed, Web of Science, SCOPUS, the Cochrane Library, grey literature, and the American clinical trials registry (www.ClinicalTrials.gov), were accessed as search engines. The studies consisted of publications on the assessment of accuracy in virtual planning in bimaxillary orthognathic surgery between 2010 and 2020. After application of the eligibility criteria, 26 articles were included, and their quality was evaluated using the methodological index for non-randomised studies (MINORS) tool and Cohen's kappa statistic in the MedCalc program (MedCalc Software Ltd). Evidence obtained by comparing the planning and surgical results, both in the maxilla and mandible, showed that there is great accuracy in virtual planning in bimaxillary orthognathic surgery.

Comparison of three different types of splints and templates for maxilla repositioning in bimaxillary orthognathic surgery: a randomized controlled trial

The selection and implementation of a plan for maxillary surgery is of the utmost importance in achieving the desired outcome for the patient undergoing two-jaw orthognathic surgery. Some splint-based and splintless methods, accompanied by computer-assisted techniques, are helpful in improving surgical plan implementation. However, randomized controlled trials focused on this procedure are lacking. This study included 61 patients who underwent bimaxillary surgeries. The patients were randomly assigned to a conventional resin occlusal splint (CROS) group, a digital occlusal splint (DOS) group, or a digital templates (DT) group, in a 1:1:1 ratio. The mean linear distance between the planned and actual postoperative positions of eight selected points on the surfaces of the maxillary teeth was selected as the outcome measure. The distance was significantly smaller in the DT group (1.17±0.66mm) when compared to both the CROS group (2.55±0.95mm, P<0.05) and DOS group (2.15±1.12mm, P<0.05). However, the difference between the CROS group and DOS group was not statistically significant. These findings indicate that using digital templates results in the best performance in transferring the surgical plan to the operation environment as compared to the other two types of splints. This suggests that the application of digital templates could provide a reliable treatment option.

Review of papers published in The British Journal of Oral and Maxillofacial Surgery and The Journal of Orthodontics regarding three-dimensional computerised planning in orthognathic surgery: 2015 - 2019

This review paper summarises articles regarding orthognathic surgical planning and computerised technology, which were published in two leading national journals in both oral and maxillofacial surgery and orthodontics. This article aims to keep readers up to date with the literature published in this rapidly progressing field.

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.

Three-Dimensional Outcome Assessments of Cleft Lip and Palate Patients Undergoing Maxillary Advancement

BACKGROUND

The aim of this retrospective case series study was to compare three-dimensional postsurgical outcomes of patients with cleft lip and palate following maxillary advancement.

METHODS

Fifty consecutive cleft lip and palate patients who underwent whole-pieced Le Fort I advancements were assigned to the major (advancement ≥ 5 mm) or minor (advancement < 5 mm) groups. Three-dimensional surgical simulation was used for presurgical evaluation and planning. Virtual triangles of the presurgical, simulated, and 6-month postoperative stages were used for comparison. Translational and angular changes of each endpoint (A-point, MxR, and MxL) on the virtual triangles and reference planes were recorded and analyzed. Relationships between possible related variables and outcome discrepancies from simulations among all subgroups were also investigated.

RESULTS

Analysis of covariance and the least significant difference test revealed that the outcome discrepancy measurements were affected by different combinations of independent variables. The reliability test showed high consistency of the authors' method for three-dimensional measurements.

CONCLUSIONS

The actual surgical outcomes of cleft lip and palate patients differed from the virtual simulations. The outcome discrepancies are impacted by multiple factors. The outcome discrepancies of all rotational surgical corrections (roll, yaw, and pitch) were positively correlated to the degree of planned surgical movement. Meanwhile, bilateral cleft lip and palate patients are more likely to incur outcome discrepancies in yaw correction with major maxillary advancement. However, a maxillary advancement cutoff value of 5 mm would not necessarily lead to significant translational outcome discrepancies among cleft lip and palate patients.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Computer-Aided Freehand Maxillary Repositioning

The authors aimed to test the hypothesis that in orthognathic surgery the maxilla could be repositioned using spatial distances from Glabella to 3 maxillary dental landmarks as references. An asymmetric skeletal Class 3 malocclusion patient was involved and bimaxillary orthognathic surgery was planned. Virtual surgery was simulated and spatial distances from Glabella to midpoint of the upper dentition (U0) and bilateral medial-buccal cusp of the first molar (6L and 6R) were measured. These distances were used as the repositioning references and were imported intraoperatively into a digital caliper after the maxilla was mobilized, the repositioning of maxilla was manipulated till all the true spatial distances reached the references. Postoperative computed tomography head model were superimposed onto the planned head model, the maxillary repositioning error was assessed using spatial distances between the pre- and postoperative dental landmarks. The asymmetric skeletal Class 3 malocclusion was corrected through bimaxillary surgery and the errors at U0, 6R and 6L was 1.37, 1.79, and 1.45 mm. The maxilla could be repositioned using spatial distances from Glabella to 3 maxillary dental landmarks as references.