Surgical complications of segmental Le Fort I osteotomy

Segmental maxillary osteotomy is a useful adjunct in orthognathic surgery for the correction of vertical and transverse maxillary deformities, but we know of few published reports that document complications. We evaluated the complication rates associated with segmental maxillary surgery in our unit by retrospective review of medical records, radiographs, and study models of 85 consecutive patients (mean age 23.3 years, range 14–51; male:female ratio 1:2) treated from 1995 to 2009. Types of deformity were anterior open bite (n = 30, 35%), transverse maxillary deficiency (n = 24, 28%), anterior open bite with transverse maxillary deficiency (n = 28, 33%), and anterior vertical maxillary excess (n = 3, 4%). There were 70 tripartite (82%), 13 bipartite (15%), and two quadripartite (2%) maxillas. Twenty-one patients (25%) had bone grafts. Fixation was done using titanium miniplates in 80 patients (94%), and titanium miniplates and resorbable plates in five (6%). The overall complication rate was 27%. Three patients (4%) had devitalisation of teeth, three (4%) developed minor periodontal defects, and one had tooth loss. Eight patients (9%) had plates removed, and two patients developed persistent postoperative palatal fistula. There was no segmental loss of bone or teeth. Our results show that complications in this cohort were relatively low, and that segmental maxillary surgery is safe as an adjunct in carefully selected cases.     

Cone beam computed tomography evaluation of tooth injury after segmental Le Fort I osteotomy

The purpose of this study was to explore the incidence of injuries to the teeth at the vertical osteotomy line after segmental Le Fort I osteotomy by examination of postoperative cone beam computed tomography (CBCT) images. Data for this retrospective case study were collected using CBCT images of 132 patients with an indication for Le Fort I osteotomy with three-piece segmentation of the maxilla. Twenty-two patients (17%, 95% confidence interval 10–23%) had dental injuries. No patient had more than one dental injury. Thirty-three patients (25%, 95% confidence interval 18–32%) had bone dehiscence of the teeth (defined as the osteotomy line passing through the periodontal ligament). Six patients had bone dehiscence involving two teeth and one patient had bone dehiscence involving three teeth. In the group in which dental injuries occurred, the preoperative interdental distance at the vertical osteotomy line was significantly shorter than the interdental distance in the group without dental injuries. In conclusion, this study demonstrated that a preoperative interdental distance of more than 2.5 mm significantly reduced the possibility of tooth injuries adjacent to the vertical osteotomy line during Le Fort I osteotomy with three-piece segmentation of the maxilla.     

Effect of maxillary surgical movement on nasal cavity and maxillary sinus dimensions and function after Le Fort I osteotomy

This study was designed to evaluate the effects of different maxillary movements performed in Le Fort I surgery on the anatomy of the nasal cavity and maxillary sinus, occurrence of rhinosinusitis, and nasal airflow. Patients were divided into three groups: group I underwent pure advancement, group II underwent advancement with yaw rotation, and group III underwent advancement with impaction movements. All evaluations were performed using pre- and postoperative computed tomography images and surveys. Twenty-eight patients were enrolled. The mean pre- and postoperative nasal air volumes in group I were 22.74 ± 6.32 cm³ and 25.17 ± 6.19 cm³, respectively, showing a significant increase (P = 0.041). The mean pre- and postoperative maxillary sinus air volumes were 33.94 ± 13.72 cm³ and 26.28 ± 14.12 cm³ in group II and 35.29 ± 9.58 cm³ and 28.65 ± 8.42 cm³ in group III, respectively, showing significant reductions (P = 0.028 and P = 0.007, respectively). For all movements, the occurrence of septum deviation and nasal airflow impairment was not statistically significant. Pure maxillary advancement movement enhanced nasal cavity air volume. The yaw rotation movement significantly increased quantitative clinical rhinosinusitis symptoms. The risk of airflow impairment following Le Fort I surgery is low.     

Longitudinal recovery pattern of neurosensory deficit after Le Fort I osteotomy

The purpose of this study was to investigate the incidence and recovery pattern of neurosensory deficit (NSD) following Le Fort I osteotomy, and to identify the possible risk factors that might contribute to the complication. A prospective longitudinal observational study on the incidence of NSD was conducted on patients who received Le Fort I osteotomy. Subjective and objective standardized neurosensory assessments were performed preoperatively as the baseline, and postoperatively at 2 weeks, 6 weeks, 3 months, 6 months, 12 months, and 24 months. Possible risk factors for NSD including patient age and sex, surgeon experience, and Le Fort I osteotomy with or without multi-segmentation were analysed. Sixty-six patients (43 female, 23 male) with 132 sides of Le Fort I osteotomy were recruited. The incidence of NSD at 2 weeks, 6 weeks, 3 months, 6 months, 12 months, and 24 months was 81.8%, 59.8%, 39.4%, 19.7%, 7.6%, and 3.2%, respectively. Subjective severity of NSD improved with time. Older age was found to be a risk factor for NSD in the early postoperative period, but there was no difference in the long-term. Patient sex, surgeon experience, and the need for multi-segmentation were not found to be related to the incidence of NSD after Le Fort I osteotomy.     

Variables associated with stability after Le Fort I osteotomy for skeletal class III malocclusion

The purpose of this study was to assess skeletal stability and predictors of relapse in patients undergoing an isolated Le Fort I osteotomy. A retrospective cohort study of 92 subjects undergoing Le Fort I osteotomy for Class III malocclusion was implemented. Predictor variables were demographic and perioperative factors. The primary outcome variable was postoperative skeletal position with relapse defined as >2 mm sagittal and/or vertical change at A-point on serial lateral cephalograms at immediate postoperative, 1 year, and latest follow-up time points. Mean advancement at A-point was 6.28 ± 2.63 mm and mean lengthening was 0.92 ± 1.76 mm. Eight subjects (8.70%) had relapse (>2 mm) in the sagittal plane, and two subjects (2.17%) in the vertical plane. No subjects required reoperation for relapse as overbite and overjet remained in an acceptable range due to dental compensation. In regression analysis, magnitude of maxillary advancement was an independent predictor of relapse in the sagittal plane (P = 0.008). There were no significant predictors of relapse in the vertical plane. This study suggests that isolated Le Fort I osteotomy for correction of skeletal Class III malocclusion is a stable procedure and that greater advancement is an independent risk factor for sagittal relapse.     

Two-point nasomaxillary fixation of the Le Fort I osteotomy: assessment of stability at one year postoperative

The purpose was to assess maxillary position among patients undergoing Le Fort I maxillary advancement with internal fixation placed only at the nasomaxillary buttresses. This was a retrospective study of patients undergoing a Le Fort I osteotomy for maxillary advancement, with internal fixation placed only at the nasomaxillary buttresses. Demographic and cephalometric measures were recorded. The outcome of interest was the change in maxillary position between immediately postoperative (T1), 6 weeks postoperative (T2), and 1 year postoperative (T3). Fifty-eight patients were included as study subjects (32 male, 26 female; mean age 18.4 ± 1.8 years). Twenty-five subjects (43.1%) had a diagnosis of cleft lip and palate. Forty-three subjects (74.1%) had bimaxillary surgery, 16 (27.6%) had bone grafts, and 18 (31.0%) had segmental maxillary osteotomies. At T3, there were no subjects with non-union, malunion, malocclusion, or relapse requiring repeat surgery. Mean linear changes between T1 and T3 were ≤1 mm. Mean angular changes between T1 and T3 were <1°. There was no significant difference in stability in multi-segment maxillary osteotomies (P =  0.22) or with bone grafting (P =  0.31). In conclusion, anterior fixation alone in the Le Fort I osteotomy results in a stable maxillary position at 1 year postoperative.     

Cranial nerve injuries in Le Fort I osteotomy: a systematic review

The aim of this systematic review was to describe the anatomical and surgical factors related to cranial nerve injuries in Le Fort I osteotomy. The protocol of this systematic review was registered in the International Prospective Register of Systematic Reviews (PROSPERO). Two independent reviewers performed an unrestricted electronic database search in the MEDLINE/PubMed, LILACS, Scopus, Web of Science, and Cochrane databases up to and including August 2018. Thirty-two articles were selected for data extraction and synthesis: 30 studies were identified in the main search and two by a manual search. The level of agreement between the reviewers was considered excellent (κ = 0.779 for study selection and κ = 0.767 for study eligibility). This study revealed that the main nerve affected was the trigeminal nerve, followed by the oculomotor, abducens, optic, facial, and vagus and accessory nerves. Cleft lip and palate patients presented the highest incidence of cranial nerve damage. Cranial nerve damage after Le Fort I osteotomy is not rare. Anatomical and structural knowledge of the patient are necessary in order to minimize the risks of cranial nerve injury in Le Fort I osteotomy.     

Three-dimensional cone beam computed tomography analysis protocols for condylar remodelling following orthognathic surgery: a systematic review

Orthognathic surgery involving the mandible can lead to remodelling of the temporomandibular joint (TMJ). Cone beam computed tomography (CBCT) provides an easily accessible three-dimensional (3D) approach to study this entity. A systematic review of the literature was performed with the aim of identifying condylar remodelling analysis protocols using CBCT-derived 3D models. The search yielded 10 eligible studies. The systematic review identified three pillars of a condylar remodelling analysis protocol that were retrievable from each of the included studies: (1) registration, (2) segmentation, and (3) analysis. The studies lacked consensus on how these pillars should be transferred to their respective protocol. Through critical assessment, criteria for a universal condylar remodelling analysis are suggested: (1) performance of a regional voxel-based registration of baseline and postoperative CBCT scans using an anatomical region not prone to postoperative changes, (2) application of a (semi-)automated 3D segmentation algorithm, (3) performance of a combination of both volumetric and surface-based 3D condylar analysis, and (4) extensive validation of each step of the protocol. The homogenization of condylar remodelling analysis protocols and their incorporation into virtual planning software suites raises the potential for the inclusion of larger numbers of patients in future prospective studies in order to gain evidence-based data.     

Accuracy of Le Fort I osteotomy with combined computer-aided design/computer-aided manufacturing technology and mixed reality

The aim of this study was to verify the reproducibility and accuracy of preoperative planning in maxilla repositioning surgery performed with the use of computer-aided design/manufacturing technologies and mixed reality surgical navigation, using new registration markers and the HoloLens headset. Eighteen patients with a mean age of 26.0 years were included. Postoperative evaluations were conducted by comparing the preoperative virtual operation three-dimensional image (Tv) with the 1-month postoperative computed tomography image (T₁). The three-dimensional surface analysis errors ranged from 79.9% to 97.1%, with an average error of 90.3%. In the point-based analysis, the errors at each point on the XYZ axes were calculated for Tv and T₁ in all cases. The median signed value deviation of all calculated points on the XYZ axes was ?0.03 mm (range ?2.93 mm to 3.93 mm). The median absolute value deviation of all calculated points on the XYZ axes was 0.38 mm (range 0 mm to 3.93 mm). There were no statistically significant differences between any of the points on any of the axes. These values indicate that the method used was able to reproduce the maxilla position with high accuracy.     

Accuracy and reliability of linear measurements using 3-dimensional computed tomographic imaging software for Le Fort I Osteotomy

Our purpose was to compare the accuracy and reliability of linear measurements for Le Fort I osteotomy using volume rendering software. We studied 11 dried skulls and used cone-beam computed tomography (CT) to generate 3-dimensional images. Linear measurements were based on craniometric anatomical landmarks that were predefined as specifically used for Le Fort I osteotomy, and identified twice each by 2 radiologists, independently, using Dolphin imaging version 11.5.04.35. A third examiner then made physical measurements using digital calipers. There was a significant difference between Dolphin imaging and the gold standard, particularly in the pterygoid process. The largest difference was 1.85 mm (LLpPtg L). The mean differences between the physical and the 3-dimensional linear measurements ranged from −0.01 to 1.12 mm for examiner 1, and 0 to 1.85 mm for examiner 2. Interexaminer analysis ranged from 0.51 to 0.93. Intraexaminer correlation coefficients ranged from 0.81 to 0.96 and 0.57 to 0.92, for examiners 1 and 2, respectively. We conclude that the Dolphin imaging should be used sparingly during Le Fort I osteotomy.     

Reaching the vertical versus horizontal target position in multi-segmental Le Fort I osteotomy is more difficult,but yields comparably stable results to one-segment osteotomy

This retrospective cohort study evaluated the postoperative outcomes of preoperatively planned positional changes for Le Fort I osteotomy in 77 patients (average age 26.6 years). Movement relapse and planning accuracy were evaluated by lateral cephalometric analysis, with an average follow-up of 257 days. In one-segment osteotomy cases, 73% of the horizontal movements were positioned within 2 mm of the surgical plan. With posterior–inferior repositioning of the maxilla, results fell within 2 mm of the prescribed plan in 60% of cases. Maxillary advancement and superior repositioning proved more stable than inferior maxillary repositioning. Relapse did not differ between three-piece and one-piece osteotomies for any movements; however, in three-piece cases, only half of the positional changes on average stayed within 2 mm of the prescribed surgical plan. Relapse did not vary with bone grafting among the groups. To summarize, in most Le Fort I osteotomy cases, the surgical plan is achieved within 2 mm, with posterior extrusion of the maxilla showing the greatest deviation both in reaching the target and maintaining the result achieved. Although maxillary segmentation makes the surgical plan more difficult to achieve, the results are at least as stable as those of one-piece osteotomies.     

Postoperative computed tomography study of pterygomaxillary separation during the Le Fort I osteotomy

Computed tomography (CT) was used postoperatively to assess the pterygomaxillary region in 12 orthognathic surgery patients who had had a Le Fort I osteotomy. Although pterygomaxillary separation was successful in all cases, in only 41.6% of the sides did fractures of the plate not occur. The incidence of low pterygoid plate fracture was 37.5% and that of high pterygoid plate fracture was 25%; 4.2% of sides showed a maxillary tuberosity fracture. Multiple fractures were observed in 8.3% of separated plates. Of 17 pterygoid plates judged clinically to be intact, only 10 were intact as assessed by CT. The significance of these findings and application of CT to evaluation of modifications to the Le Fort I osteotomy is discussed.     

The impact of Le Fort I advancement and bilateral sagittal split osteotomy setback on ventilation during sleep

The impact of orthognathic surgery for class III malocclusion on ventilation during sleep was examined using a comparison of pre- and post-surgical respiratory parameters. 21 patients with both maxillary hypoplasia and mandibular excess underwent Le Fort I osteotomy and advancement together with bilateral sagittal split osteotomy (BSSO) setback. Respiratory parameters, ECG and position of the body were monitored before surgery and postoperatively after the fixation removal (mean 8.5 months). Average Le Fort I advancement was 4.44 mm, BSSO setback was 4.96 mm. Generally, the orthognathic procedure worsened breathing function during sleep, as reflected in significant increase of index of flow limitations and decrease in oxygen saturation. The posterior airways space decreased to 75% of its original volume, the distance between mandibular plane and hyoid bone increased to 133%. The results indicate that bimaxillary surgery for class III malocclusion increased upper airway resistance. A young person would probably be able to balance such a decline in respiratory function using different adaptive mechanisms, but the potential impact of orthognathic surgery on the upper airways should be incorporated in a treatment plan.     

Precision of Le Fort I osteotomy: planning versus outcome. A multi-centre retrospective study

Introduction: The purpose of this study was to evaluate the accuracy of Le Fort I surgery by comparing planned surgical movements with actual outcomes.

Materials and methods: A minimum number of seven consecutive cases that had undergone a Le Fort I osteotomy procedure alone or in combination with a mandibular osteotomy from six different hospital units in the East of England between 2009 and 2010 were identified. A total of 56 cases met the inclusion criteria where surgical splints were used and model surgery had been performed. Pre- and post-operative lateral cephalograms were digitised using Dolphin^© imaging software (Version 10.0) and three cephalometric points were assessed to measure precision of surgical movements: A point (A-pt); Upper incisor tip (U1 tip); and Upper first molar occlusal point (U6 occ). The final position of the maxilla was compared to the planned position.

Results: In 71% of cases surgical movements were within 2?mm and 20% of this group were within 1?mm of the predicted position. The mean accuracy was 1.39?mm (SD 0.92?mm) for the former and 0.78?mm (SD 0.58?mm) for the latter. Accuracy correlated negatively with increased surgical complexity, particularly posterior differential impactions of the maxilla. There was no statistically significant difference between centres.

Conclusions: Pre-operative surgical planning of Le Fort I osteotomies was generally accurate. This study demonstrates that different operators across six centres produced consistent surgical outcomes and this confirms previously reported data.     

Two-year follow-up of changes in bite force and occlusal contact area after intraoral vertical ramus osteotomy with and without Le Fort I osteotomy

This study was performed to examine the longitudinal changes in bite force and occlusal contact area after mandibular setback surgery via intraoral vertical ramus osteotomy (IVRO). Patients with mandibular prognathism who underwent IVRO (surgical group: 39 men and 39 women) were compared with subjects with class I skeletal and dental relationships (control group; 32 men and 35 women). The surgical group was divided into two subgroups: 1-jaw surgery (n = 30) and 2-jaw surgery (n = 48). Bite force and contact area were measured in maximum intercuspation with the Dental Prescale System before treatment, within 1 month before surgery, and at 1, 3, 6, 9, 12, and 24 months postsurgery. A linear mixed model was used to investigate the time-dependent changes and associated factors. Bite force and contact area decreased during presurgical orthodontic treatment, were minimal at 1 month postsurgery, and increased gradually thereafter. The 1-jaw and 2-jaw subgroups showed no significant differences in bite force. The time-dependent changes in bite force were significantly different according to the contact area (P < 0.05). The results of this study suggest that bite force and occlusal contact area gradually increase throughout the postsurgical evaluation period. Increasing the occlusal contact area may be essential for improving bite force after surgery.     

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.     

How accurate is digital-assisted Le Fort I maxillary osteotomy? A three-dimensional perspective

The aim of this study was to evaluate the surgical accuracy of Le Fort I surgery compared to the three-dimensional (3D) virtual planning. Fifty-five patients (29 males, 26 females; age range 15–58 years) with skeletal class III malocclusion, who underwent bimaxillary surgery were included. A validated 3D accuracy assessment tool was utilized to assess the surgical accuracy of the maxillary positioning. For translational movements, the least amount of error was associated with mediolateral translation, whereas the surgical accuracy for anteroposterior and superoinferior translation showed a tendency towards a more posterior and inferior positioning of the maxilla compared to the planning. For rotational movements, the highest discrepancy was observed for pitch. Linear regression showed increased inaccuracy with increasing advancement for anteroposterior, superoinferior and pitch movements. To conclude, 3D virtual planning of maxilla was generally accurate when compared to achieved outcome for skeletal class III patients undergoing bimaxillary surgery.     

Pulp canal obliteration after Le Fort I osteotomy

Abstract A longitudinal study of 51 patients was carried out to determine the frequency of pulp canal obliteration (PCO) after Le Fort I osteotomy for the correction of dentofacial anomalies and to analyse pre- and peroperative factors influencing the development of PCO. PCO developed in 14 (2.3%) of 617 maxillary teeth followed for an average period of 28 months (range 11–59). The highest frequency of PCO was demonstrated in canines (6.0%) and premolars (4.4%). Total PCO was present in 9 teeth and partial PCO in 5 teeth. PCO was more frequent among teeth adjacent to a vertical interdental osteotomy than in teeth with no relation to a vertical osteotomy (p< 0.0001). Change in blood supply after the operation was suggested to be responsible for PCO, although it might have been effected by the combined surgical and orthodontic treatment. Long-term follow-up, including periapical radiographs, of teeth with PCO is suggested, as pulp necrosis may develop many years after surgery.     

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.