Skeletal changes after midface surgery in patients with craniofacial deformities: a three-dimensional quantification method.

To determine the skeletal changes after midface surgery in patients with syndromic craniosynostosis who underwent Le Fort III (LFIII), monobloc (MB), or facial bipartition (FB). This was a retrospective study including 75 patients: 33 treated by LFIII, 29 by MB, and 13 by FB. Twenty-five had a diagnosis of Apert, 39 Crouzon, and 11 craniofrontonasal syndrome. A three-dimensional mesh was created from the preoperative scan and registered to the postoperative scan to visualise the advancement. LFIII at age 7-12 years effectuated a higher mean advancement in the maxillary (15.5 mm) and zygomatic (7.6 mm) regions when compared to ≥13 years (10.2 mm and 5.5 mm). After MB, mean advancement of the fronto-orbital region was higher at <7 years (16.4 mm), and similarly lower at ages 7-12 (13.8 mm) and ≥13 (12.5 mm). The mean preoperative inter-dacryon distance (34.4 ± 4.4 mm) was reduced by 8.7 ± 4.2 mm after FB without distraction (n = 10). More advancement was seen when midface surgery was performed at a younger age, due to more severe cases and a desire for overcorrection. The highest mean advancement was observed in the fronto-orbital region. Antero-inferior rotational movement was seen after all three techniques.

On the feasibility of minimally invasive Le Fort I with patient-specific implants: Proof of concept.

A novel approach to Le Fort I osteotomy is presented, integrating patient-specific implants (PSIs), osteosynthesis and cutting guides within a minimally invasive surgical framework, and the accuracy of the procedure is assessed through 3D voxel-based superimposition. The technique was applied in 5 cases. Differences between the surgical plan and final outcome were evaluated as follows: a 2-mm color scale was established to assess the anterior surfaces of the maxilla, mandible and chin, as well as the condylar surfaces. Measurements were made at 8 specific landmarks, and all of them showed a mean difference of less than 1 mm. In conclusion, the described protocol allows for minimally invasive Le Fort I osteotomy using PSIs. Besides, although the accuracy of the results may be limited by the small sample size, the findings are consistent with those reported in the literature. A prospective comparative study is needed to obtain statistically significant results and draw meaningful conclusions.

Use of the Smith's Spreader as a Self-Retaining Retractor in the Direct Approach to Clival Tumours - A Technical Note.

The traditional Le Fort level 1 osteotomy has proven to be an effective in approaching central skull base lesions. The challenge being - stabilization of the down-fractured maxilla in an amenable position for tumour resection. The authors describe a simple technique to overcome the task of stabilizing the down-fractured maxilla.

Mandibular autorotation: a critical virtual parameter in clinical decision-making regarding maxilla-first versus mandible-first sequence.

Large degrees of mandibular autorotation during intermediate splint design are prone to transfer error and decrease accuracy. The purpose of this study was to evaluate the amount of mandibular autorotation necessary to design intermediate splints for maxilla- and mandible-first sequences using virtual planning software, to help the clinical decision-making regarding the most adequate sequence for each patient. The influence of specific orthognathic movements (different vertical and sagittal changes at the Le Fort I level, cant correction) and the type of maxillofacial deformity (skeletal Class II, III, anterior open bite) were evaluated to identify those that would require higher levels of autorotation for each sequence. Three-dimensional virtual surgical planning data of 194 patients were reviewed (126 female, 68 male; mean age 26.5 ± 11.0 years; 143 skeletal Class II, 51 skeletal Class III) and subgroup analyses were conducted using the Kruskal-Wallis test and post-hoc pairwise comparisons. As an additional parameter (mandibular autorotation), maxilla-first is indicated for bimaxillary osteotomies with Le Fort I posterior intrusion, anterior open bite, and skeletal Class III, while mandible-first is recommended for Le Fort I global extrusion, especially with maxillary cant correction.

Le fort I osteotomy with or without concomitant removal of upper third molars: A prospective cohort study of intraoperative findings, related complications, and level of pterygomaxillary separation after down-fracture.

The main objective of our study was to assess the clinical implications of concomitant intraoperative removal of maxillary third molars (M3M) with the Le Fort I osteotomy 'twist' technique (LF1twist). A prospective comparative study was carried out regarding the necessity of bone trimming around the pedicle, intra- and postoperative complications, surgery time, and the level of pterygomaxillary junction (PMJ) separation following LF1twist with concomitant intraoperative removal of M3M (test group) versus LF1twist alone (control group). Outcome parameters were assessed from clinical and radiographic measurements. In total, 100 surgery sites were included (50 in each group). The mean surgery time was 53.4 ± 7.8 min, with nonsignificant differences between groups. The frequency of intraoperative complications was negligible, with no significant differences between groups - though all bleeding events (n = 4) occurred when M3M was not removed concomitantly. No postoperative complications were recorded. Percentages of disarticulations occurring at the PMJ were similar in both groups. In conclusion, the results demonstrate that removal of M3M in conjunction with LF1twist does not imply additional surgery time, or differences regarding the level of PMJ separation or perioperative complications. Furthermore, the concomitant procedure reduces the amount of maxillary and palatal bone in the disjunction area, which facilitates down-fracture and field clearing for maxillary repositioning.

What is the angular accuracy of regional voxel-based registration for segmental Le Fort I and genioplasty osteotomies?

Among the accuracy analysis techniques for orthognathic surgery, regional voxel-based registration (R-VBR) has robust data, but remains unvalidated for smaller jaw segments. The purpose of this study was to validate the angular accuracy of R-VBR for segmental Le Fort I (SLFI) and genioplasty osteotomies. Postoperative cone beam computed tomography (CBCT) of consecutive patients with three-piece SLFI or genioplasties was rotated to a known pitch/roll/yaw (P/R/Y). Using R-VBR, a copy of the raw CBCT was superimposed onto the rotated CBCT at four mutual regions of interest (ROI): anterior, right posterior, and left posterior maxilla, and chin. The P/R/Y of each was subtracted from those of the rotated CBCT to calculate the angular error. The predictor and outcome variables were ROI and absolute angular error, respectively. The accuracy threshold was 0.5°. Ten SLFI and 34 genioplasties were analyzed based on the sample size calculation. The one-sample t-test and Wilcoxon signed rank test were applied in the analysis. The mean absolute error was 0.20-0.54° for the maxillary segments (all P ≤ 0.01) and 0.83-2.51° for the genioplasty segments (all P < 0.001). R-VBR has variable angular accuracy for SLFI osteotomies and may be insufficient for genioplasty. The findings may allow the design and interpretation of studies on SLFI and genioplasty with greater rigor, thereby contributing to minimizing the discrepancy between planned and achieved outcomes.

Effects of distraction osteogenesis with Le Fort osteotomies on upper airway volumes: a systematic review and meta-analyses.

OBJECTIVE: Distraction osteogenesis is one of the treatment options in patients with severe maxillomandibular abnormalities to treat morphological and respiratory problems (obstructive sleep apnea syndrome). The study aimed to evaluate the effect of Le Fort I, II and III distraction osteogenesis (DO) on upper airway dimensions and respiratory function. METHODS: Electronic search was performed in PubMed, Scopus, Embase, Google Scholar and Cochrane databases. Studies that only involved two dimensional analyses were excluded. Besides, studies that performed DO in conjunction with orthognathic surgery were not considered. NIH quality assessment tool was used to evaluate the risk of bias. Meta-analyses were performed to assess sleep apnea indices and the mean differences in the airway dimensions before and after DO. Gradings of Recommendations, Assessment, Development and Evaluation were used to analyze the evidence level. RESULTS: Among the 114 studies that went under full-text analyses, 11 articles met the inclusion criteria. Results of the quantitative analyses showed that maxillary Le Fort III DO significantly increased the amounts of oropharyngeal, pharyngeal and upper airway volumes. However, apnea-hypopnea index (AHI) showed a non-significant improvement after this procedure. Besides, the dimensions of the airways increased with Le Fort I and II DO, according to a qualitative analysis. Considering the design of the included studies, our results had a low level of evidence. CONCLUSION: Maxillary Le Fort DO does not significantly impact AHI, while it significantly increases the airway dimensions. Meanwhile, multicentric studies with standardized evaluation are still required to confirm the effects of maxillary Le Fort DO on airway obstruction.

Impact of 3-dimensional anatomical changes secondary to orthognathic surgery on voice resonance and articulatory function: a prospective study.

An evaluation was made of the impact of orthognathic surgery (OS) on speech, addressing in particular the effects of skeletal and airway changes on voice resonance characteristics and articulatory function. A prospective study was carried out involving 29 consecutive patientssubjected to OS. Preoperative, and short and long-term postoperative evaluations were made of anatomical changes (skeletal and airway measurements), speech evolution (assessed objectively by acoustic analysis: fundamental frequency, local jitter, local shimmer of each vowel, and formants F1 and F2 of vowel /a/), and articulatory function (use of compensatory musculature, point of articulation, and speech intelligibility). These were also assessed subjectively by means of a visual analogue scale. Articulatory function after OS showed immediate improvement and had further progressed at one year of follow up. This improvement significantly correlated with the anatomical changes, and was also notably perceived by the patient. On the other hand, although a slight modification in vocal resonance was reported and seen to correlate with anatomical changes of the tongue, hyoid bone, and airway, it was not subjectively perceived by the patients. In conclusion, the results demonstrated that OS had beneficial effects on articulatory function and imperceptible subjective changes in a patient's voice. Patients subjected to OS, apart from benefitting from improved articulatory function, should not be afraid that they will not recognise their voice after treatment.

Predictability of the virtual surgical plan for orthognathic surgery with the mandible surgery first sequence.

The aim of this study was to compare the virtually planned position to the postoperative position of the maxilla, having performed the maxilla-first sequence or mandible-first sequence orthognathic surgery. An audit of 64 patients who underwent bimaxillary surgery between 2017 and 2020 was performed. Thirty patients had maxilla-first surgery and 34 had mandible-first surgery. The planned and post-surgical positions were analyzed using specific skeletal landmarks. Differences were calculated and the two-sample t-test was used to compare the groups. Measured differences between the planned and postoperative results differed significantly between the mandible-first and maxillary-first surgery groups (P < 0.001). The maxillary central incisors were under-advanced in the anterior-posterior direction in both groups. Most data points showed deviation from the surgical plan ≤ 2 mm and ≤ 4°. Secondarily, maxillary under-advancement in the mandible-first cohort was evaluated; these patients were subdivided into rigid and non-rigid fixation groups. The non-rigid fixation group showed less accuracy compared to the rigid fixation group, which was statistically significant (P = 0.014). The findings of this study demonstrate that virtual surgical planning can be less accurate in predicting the maxillary incisor position when performing mandible-first surgery, but this inaccuracy is within the acceptable range and can be mitigated by rigid fixation of the mandible.

Helical distraction is superior to linear distraction in maxillary distraction osteogenesis: an in silico study.

This in silico kinematic study was performed to evaluate the best attainable outcomes of maxillary distraction osteogenesis given the constraints of linear and helical motion. The study sample included the retrospective records of 30 patients with maxillary retrusion who had been treated with distraction or had been recommended this treatment. The primary outcomes were the errors of linear and helical distraction. The study measured two types of error: misalignment of key upper jaw landmarks and misalignment of the occlusion. Concerning the misalignment of key landmarks, the median misalignments resulting from helical distraction were minimal; the interquartile ranges were also minimal. The median misalignments and interquartile ranges that resulted from linear distraction were significantly larger. Regarding the occlusal misalignments, helical distraction produced minor occlusal misalignments, while linear distraction produced significantly larger errors. The results of this study confirmed that helical motion is the ideal motion for LeFort I distraction.

Transmucosal pterygomaxillary disjunction using a piezoelectric device, in the context of the minimally invasive Le Fort I osteotomy protocol.

The aim of this study was to assess the accuracy and clinical implications of pterygomaxillary junction (PMJ) disjunction with a transmucosal PMJ osteotomy using a piezoelectric hand-piece device, in the context of Le Fort I osteotomy, by evaluating the level of PMJ disarticulation and the need for bone trimming around the pedicle. An ambidirectional 1-month follow-up cohort study was designed involving consecutive patients undergoing minimally invasive maxillary Le Fort I osteotomy through the twist technique. Two cohorts were defined according to whether or not the transmucosal PMJ osteotomy was performed. The site of PMJ disjunction was analysed radiographically. A total of 114 patients were included in the study, 57 in each group. The overall accuracy of the PMJ disjunction path was higher in the test group (43.9%) than in the control group (15.8%). Multiple logistic regression analysis identified the need for bone trimming (odds ratio 0.02; P < 0.001) and removal of the upper third molar (odds ratio 0.17; P < 0.001) as relevant factors. In conclusion, compared with the originally described twist technique, combination of the latter with the PMJ osteotomy increased its accuracy at the level of the PMJ. As a result, there is a decrease in resistance during down-fracture and decrease in the need for bone trimming around the pedicle, with preservation of the minimally invasive concept.

Cone beam computed tomography volumetric airway changes after orthognathic surgery: a systematic review.

The aim of this systematic review was to provide a structured overview of three-dimensional airway volume changes in relation to various orthognathic surgeries. Clinical human studies performing pre- and postoperative three-dimensional airway volume assessments to investigate volumetric changes of the airway after orthognathic surgery were included. Pre-determined inclusion and exclusion criteria were applied in an extensive search of the PubMed, Embase, and Web of Science electronic databases. The cut-off date was set to January 1, 2022. Forty-one articles reporting retrospective and prospective case-control and case series studies were included. All studies were determined to be of medium quality (moderate risk of bias). The included studies were categorized by type of intervention. Pre- and postoperative volumes were extracted from the available data, and volume changes as a percentage of the preoperative levels were calculated. Isolated mandibular setback surgery generally decreased the airway volume. Isolated maxillary or mandibular advancement, bimaxillary advancement, and surgically assisted maxillary expansion generally increased the airway volume in the total airway and oropharynx, among which the effect of bimaxillary advancement surgery appeared most significant. High heterogeneity exists in the terminology and definitions of the airway and its segments. A more uniform methodology for airway volume measurement is needed to provide an insight into the impact on the airway of specific types of surgical intervention. In conclusion, airway volumes are affected after orthognathic surgery, which may be of clinical significance, especially in patients who are predisposed to obstructive sleep apnoea.

Postoperative skeletal stability at the one-year follow-up after splintless Le Fort I osteotomy using patient-specific osteosynthesis versus conventional osteosynthesis: a randomized controlled trial.

The purpose of this study was to assess the 1-year skeletal stability of the osteotomized maxilla after Le Fort I surgery, comparing conventional osteosynthesis with patient-specific osteosynthesis. Patients were assigned to a conventional or patient-specific osteosynthesis group using prospective randomization. The primary outcome was the three-dimensional change in postoperative skeletal position of the maxilla between the 2-week and 1-year follow-up cone beam computed tomography scans. Fifty-eight patients completed the protocol for the 2-week postoperative analysis, and 27 patients completed the 1-year follow-up study protocol. Of the 27 patients completing the entire protocol, 13 were in the conventional group and 14 in the patient-specific osteosynthesis group. The three-dimensional translation analysis showed that the use of the patient-specific osteosynthesis resulted in a skeletally stable result, comparable to that of conventional miniplate fixation. For both the patient-specific osteosynthesis and conventional miniplate fixation groups, median translations of less than 1 mm and median rotations of less than 1° were observed, indicating that both methods of fixation resulted in a stable result for the 27 patients examined. For the Le Fort I osteotomy, the choice between patient-specific osteosynthesis and conventional osteosynthesis did not affect the postoperative skeletal stability after 1 year of follow-up.

Buccal fat pad as a sealant in palatal mucosa tearing: technical note.

For patients with a dentofacial deformity undergoing a planned segmentation of the maxilla for the management of a transverse maxillary arch discrepancy, palatal mucosa tearing may occur during sawing or palatal expansion traction, giving rise to an oronasal communication. This technical note describes the covering of a tear in the palatal mucosa using a buccal fat pad (BFP) flap, in the context of maxillary segmentation during Le Fort I osteotomy. Through the limited buccal incision used for the Le Fort I osteotomy, a small incision is made in the right periosteum posteriorly, and a supraperiosteal dissection is performed to access the BFP. After a sufficient amount of flap is made available, it is gently introduced through the osteotomy gap until it reaches the palatal mucosa defect and is then sutured. In the patient case presented, the palatal mucosa healed fully within 18 days, and the patient reported no nasal regurgitation of food, defective speech, fetid odour, bad taste, or upper respiratory tract or ear infection during the postoperative period. This technique using a BFP flap should therefore be considered in the context of unexpected tearing of the palatal mucosa in patients undergoing a segmented Le Fort I osteotomy.

Orthognathic Surgery for Management of Gummy Smile.

Excessive gingival show is mainly caused by hypermobility of the upper lip, altered passive eruption, gingival hyperplasia, and bony maxillary vertical excess. Orthognathic surgery is the optimal treatment option for patients with moderate and severe vertical maxillary excess. Surrounding anatomic structures and soft tissue changes such as alternation in the nasal morphology confine the amount of impaction. Therefore, Le Fort 1 may be performed in conjunction with horseshoe osteotomy or partial turbinectomy. The possible necessity of further mandibular orthognathic surgeries and chin repositioning has to be considered. No common major complication and long-term relapse have been reported for maxillary impaction.

Le Fort I osteotomy with segmentation for the treatment of maxillary dentoalveolar protrusion: a single-centre, 10-year outcome study.

A retrospective study was conducted to evaluate the stability and complications of Le Fort I osteotomy with segmentation for the treatment of bimaxillary dentoalveolar protrusion. A total of 120 consecutive patients who had undergone orthognathic surgery between 2008 and 2017 at a single centre were recruited. Lateral cephalometric radiographs were taken before surgery, within 6 weeks after surgery, and at 2 years after surgery. U1-SN and U1-PP underwent mean uprighting of 8.7° and 9.6°, respectively, and mean relapse of 2.1° and 2.6°, respectively (both P < 0.05). The only significant risk factor for relapse was the use of intermaxillary fixation (risk ratio (RR) 1.2, P = 0.01). The most common complication was wound dehiscence (41.7%), which was a significant risk factor for wound infection (RR 3.3, P < 0.01) and fixation hardware exposure (RR 3.7, P < 0.01). Other common complications were gingival recession (40.8%), periodontal bone loss (40%), and blood loss requiring transfusion (26.7%), the latter of which was associated with the preoperative diagnosis of vertical maxillary excess (RR 2.4, P = 0.01). Some degree of relapse occurred in more than 90% of the patients by 2 years after surgery. The procedure is not without risks and complications but may be useful in severe cases.

POST-SURGICAL NEUROSENSORY DYSFUNCTION OF INFERIOR ALVEOLAR NERVE IN BILATERAL SAGITTAL SPILT OSTEOTOMY OF THE MANDIBLE USING SAW VERSUS PIEZOTOME: A SYSTEMATIC REVIEW AND META-ANALYSIS.

PURPOSE: The purpose of this systematic review was to compare neuro-sensory dysfunction incidence between saw and piezotomes in patients requiring bilateral sagittal split osteotomy. METHODS: Searches were performed electronically in 4 databases (PubMed, LILACS, Cochrane Library, and grey literature) up to September 2020 and manually to identify studies addressing the subject. Randomized and non-randomized clinical trials were included. RESULTS: Six studies met the eligibility criteria with a total number of 284 participants. The risk of bias assessment for randomized clinical trials was high, and for non-randomized clinical trials was critical and serious. Regarding inferior alveolar neuro-sensory dysfunction, the meta-analysis showed no significant difference between saw and piezotome 1 week [RR = 0.99, 95% CI (0.90, 1.08) P = 0.79], and 3 months [RR = 0.39, 95% CI (0.09, 1.75) P = 0.22], post-operatively. CONCLUSIONS: For patients requiring bilateral sagittal split osteotomy, piezotomes seem to offer no advantage over conventional saws regarding the incidence of neurosensory disturbance. Follow-up periods longer than 3 months may reveal faster physiologic regain of sensations. They seem to be safer than conventional saws regarding blood loss. However, proper training for using the device is mandatory, while considering the longer operating time required. Further RCTs are still recommended to improve the level of evidence.

Wafer as an adjunct to plating patient-specific implants for the multi-segment maxilla: a useful tool.

Virtual surgical planning for orthognathic surgery using patient-specific implants (PSI) is usually waferless nowadays. However, without an occlusal wafer, difficulties arise in controlling the accuracy of multi-segment maxillary osteotomies, especially for expansion and rotational movements of each segment. It is technically challenging intraoperatively to manipulate multiple segments to fit into the PSI, as the relatively small bone segments need to be secured into the PSI while simultaneously achieving individual segment movements in all planes and with potential bony interferences with each other. Therefore, the use of a maxillary tooth-supported surgical guide is proposed and described. When the guide is inserted before the PSI, it overcomes difficulties in handling multiple maxillary segments and facilitates achieving maximal positional precision of each individual bone segment. The guide enables multiple smaller segments to behave as one unit with the designated occlusion whilst visualizing bony interferences before PSI plating is commenced. Adding a tooth-borne surgical guide in the form of a wafer and a customized arch bar is a cost-effective method to enhance accuracy in virtually planned multi-segment maxillary surgery. Further investigations are required to validate the accuracy and advantages of using wafers and PSI in multi-segment maxillary and mandibular orthognathic surgeries.

Clinical feasibility evaluation of digital dental articulation for three-piece maxillary orthognathic surgery: a proof-of-concept study.

Digital dental articulation for three-piece maxillary orthognathic surgery is challenging. The purpose of this proof-of-concept study was to evaluate the clinical feasibility of a newly developed mathematical algorithm to digitally establish the final occlusion for three-piece maxillary surgery. Five patients with jaw deformities who had undergone a three-piece double-jaw surgery that was planned virtually were randomly selected for this study. The final occlusion had been hand-articulated using stone casts, scanned into the computer and used in the surgery. These hand-articulated occlusions served as the control group. To form the experimental group, the three-piece maxillary dental arch was articulated again automatically from the patient's original occlusion using the mathematical algorithm. The hand- and algorithm-articulated occlusions were then evaluated qualitatively by two experienced orthodontists. A quantitative evaluation was also performed. The results of the qualitative evaluation showed that all of the three-piece occlusions, hand- and algorithm-articulated, were clinically acceptable based on the American Board of Orthodontics grading system. When compared, two of the algorithm-articulated occlusions were clearly better (40%), one was the same (20%), and two were slightly worse (40%) than the hand-articulated occlusions. All of the quantitative measurements were comparable between the two articulation methods. In conclusion, the results of this study demonstrate that it is clinically feasible to digitally articulate the three-piece maxillary arch to the intact mandibular dental arch.

Alar cinch sutures in orthognathic surgery: scoping review and proposal of a classification.

Orthognathic surgery and the Le Fort I osteotomy result in noticeable alterations to the nasal/nasolabial anatomy. The alar base cinch technique is a surgical technique to control lateralization of the base of the nose and is well described in the literature. The aim of this scoping review was to identify every unique alar cinch suture technique reported in orthognathic surgery and to propose a classification for the different techniques described. A search was conducted in the PubMed, Cochrane Library, and Scopus electronic databases covering the period May 1980 to July 2020, which identified 10 articles that were eligible for this review. Among these, there were several proposals for modifications to the technique, and different studies to show the effectiveness of one type among all others. Despite observing multiple techniques and variations of these while performing this review, the lack of a classification for alar cinch suture was noticed. Therefore, we propose a classification of the alar cinch suture that includes four types, which cover all of the cinching techniques described. It is believed that the use of a standardized classification may be useful to avoid duplicate publishing of techniques and to set a standard for further studies.