The stability of facial osteotomies. 4. Maxillary and mandibular (with or without chin) advancement with rigid internal fixation

The short-term (6 weeks postoperative) and long-term (12 months postoperative) horizontal skeletal stability of combined maxillary and mandibular advancement was evaluated by cephalometric analysis of 15 patients.
The mean horizontal advancement of the maxilla was 5.84 mm. Six weeks later a mean horizontal relapse of 0.03 mm (0.05%) was identified. The mean horizontal relapse at long-term follow-up was 0.59 mm (10.1%).
The mean horizontal advancement of the mandible was 12.35 mm at menton and 12.65 mm at pogonion. At 6 weeks, mean horizontal relapse, respectively at the above landmarks, was 0.11 mm and 0.21 mm (1.3%). The mean horizontal relapse at long-term follow-up was 2.19 mm and 1.98 mm (16.6%) respectively for the same landmarks.
Subjectively and objectively, improvements were seen in facial aesthetics and dental occlusion. The results indicate that rigid fixation of osteotomies undertaken to correct 'horizontal facial deficiency' is a surgically predictable and relatively stable procedure when reviewed up to 12 months after surgery.     

The stability of facial osteotomies. 2. Mandibular advancement with bicortical screw fixation

Surgical repositioning of the dento-skeletal components of the lower third of face, combined with appropriate orthodontic treatment, can be used to improve function and aesthetics. However, the attainment of three-dimensional stability following corrective jaw surgery continues to be a major problem in the post-surgical period.
This paper examines the short-term (6 week postoperative) and long-term (12 months postoperative) horizontal skeletal stability of bilateral sagittal split mandibular advancement in 15 patients. The mean horizontal advancement of the mandible was 6.1 mm. Six weeks later, a mean continued forward movement of 0.16 mm was identified. The mean relapse at long-term follow-up was 0.46 mm (7.5%). Results indicate that rigid bicortical screw fixation of bilateral sagittal split osteotomies undertaken to correct horizontal lower dentofacial deficiency is both statistically and surgically predictable and stable when reviewed up to twelve months after surgery.     

Importance of soft tissue for skeletal stability in maxillary advancement in patients with cleft lip and palate.

OBJECTIVE: Assessment of stability of the advanced maxilla after two-jaw surgery and Le Fort I osteotomy in patients with cleft palate based on soft tissue planning. SUBJECTS: Between 1995 and 1998, 15 patients with cleft lip and palate deformities underwent advancement of a retruded maxilla, without insertion of additional bone grafts. Eleven patients had bimaxillary osteotomies and four patients only a Le Fort I osteotomy. Relapse of the maxilla in horizontal and vertical dimensions was evaluated by cephalometric analysis after a clinical follow-up of at least 2 years. RESULTS: In the bimaxillary osteotomies, horizontal advancement was an average 4 mm at point A. After 2 years, there was an additional advancement of point A of an average of 0.7 mm. In the mandible, a relapse of 0.8 mm was seen after an average setback of 3.9 mm. In the four patients with Le Fort I osteotomy, point A was advanced by 3.8 mm and the relapse after 2 years was 0.9 mm. Vertical elongation at point A resulted in relapse in both groups. Impaction of the maxilla led to further impaction as well. CONCLUSION: Cephalometric soft tissue analysis demonstrates the need for a two-jaw surgery, not only in severe maxillary hypoplasia. Alteration of soft tissue to functional harmony and three-dimensional correction of the maxillomandibular complex are easier to perform in a two-jaw procedure. It results in a more stable horizontal skeletal position of the maxilla.     

The skeletal stability of one-piece Le Fort 1 osteotomy to advance the maxilla; Part 1. Stability resulting from non-bone grafted rigid fixation

During the past decade, we have increasingly preferred to do a one-piece Le Fort 1 osteotomy to advance the maxilla, sometimes in isolation to treat patients with maxillary retrusive skeletal Class III patients or combined with mandibular advancement to treat bimaxillary retrusive skeletal Class II. Clinical impressions of rigid fixation techniques have indicated that there is improved stability when compared with wire fixation. There are few studies in the literature that have addressed relapse following one-piece Le Fort 1 osteotomy to advance the maxilla. Such surgery involves one single spatial movement and thereby eliminates other possible surgical variables, which may impact on the degree of stability achievable postoperatively. We studied 45 patients who had undergone a uniform one-piece maxillary advancement with elimination of controllable variables, apart from 15 patients who had simultaneous mandibular advancement. Rigid fixation was adopted throughout the study. The mean surgical change documented was 7.42 mm. The mean stability calculated at 12 months revealed a relapse of 0.72 mm (10%). This was not significant (P = 0.3). We conclude that the Le Fort 1 advancement osteotomy is a stable and surgically predictable procedure that gives only slight relapse at 12 months.     

Stability of the Le Fort I osteotomy with anterior internal fixation alone: a case series.

PURPOSE: The purpose of this case series was to evaluate the late postsurgical stability of the Le Fort I osteotomy with anterior internal fixation alone and no posterior zygomaticomaxillary buttress internal fixation. PATIENTS AND METHODS: Sixty patients with maxillary vertical hyperplasia and mandibular retrognathia underwent a 1-piece Le Fort I osteotomy of the maxilla with superior repositioning and advancement or setback. A bilateral sagittal split ramus osteotomy for mandibular advancement was also performed in 22 patients. Stabilization of each maxillary osteotomy was achieved using transosseous stainless steel wires and/or 3-hole titanium miniplates in the piriform aperture region bilaterally, with no zygomaticomaxillary buttress internal fixation. (Twelve of the 60 identified patients were available for a late postoperative radiographic evaluation.) Lateral cephalometric radiographs were taken preoperatively (T1), early postoperatively (T2), and late postoperatively (T3) to analyze skeletal movement. RESULTS: These 12 patients (5 male, 7 female) had a mean age of 24.5 years at surgery. Mean time from surgery to T2 was 41.2 days; mean time from surgery to T3 was 14.8 months. One patient received anterior wire osteosynthesis fixation, while 11 patients received both anterior titanium miniplate internal skeletal fixation and anterior wire osteosynthesis fixation. Six patients underwent Le Fort I osteotomy with genioplasty, 1 patient underwent Le Fort I osteotomy with bilateral sagittal split ramus osteotomy, and 5 patients underwent Le Fort I osteotomy with bilateral sagittal split ramus osteotomy and genioplasty. These 12 patients all underwent maxillary superior repositioning with either advancement (11 patients) or setback (1 patient). Statistically significant surgical (T2-T1) changes were found in all variables measured. In late postsurgical measurements (T3-T2), all landmarks in the horizontal and vertical plane showed statistically significant skeletal stability. CONCLUSION: This case series suggests that anterior internal fixation alone in cases of 1-piece Le Fort I maxillary superior repositioning with advancement has good late postoperative skeletal stability.     

Skeletal stability of Le Fort I osteotomy in patients with isolated cleft palate and bilateral cleft lip and palate

The skeletal stability of Le Fort I osteotomy was evaluated retrospectively in 14 patients with isolated cleft palate (CP, mean age 27.2 years) and 11 patients with bilateral cleft lip and palate (BCLP, mean age 23.7 years). The osteotomy was fixed with titanium plates and the osteotomy gap was grafted with autologous bone. Neither intermaxillary fixation nor occlusal splints were used postoperatively. Skeletal stability was analysed both horizontally and vertically by cephalograms taken shortly before operation, immediately afterwards, and at six months and at one year postoperatively. In the CP group the mean maxillary horizontal advancement (point A) was 4.7 mm (range 0.3-7.8) and the mean vertical lengthening 3.6 mm (range 0.7-6.1). One year postoperatively the mean relapse was 8.5% (0.4 mm) horizontally and 16.7% (0.6 mm) vertically. In the BCLP group the mean horizontal advancement was 5.3 mm (range 0.2-10.7) and the mean vertical lengthening 7.3 mm (range 0.6-11.8). The mean postoperative relapse was 9.4% (0.5 mm) horizontally and 17.8% (1.3 mm) vertically. The skeletal stability and relapse were similar in both cleft types although BCLP patients had more residual cleft problems and their mean surgical advancement was greater. There was great individual variation.     

Stability of maxillary advancement for correction of skeletal Class III malocclusion after combined maxillary and mandibular procedures: preliminary results of an active control equivalence trial for semirigid and rigid fixation of the maxilla

In this paper preliminary results are presented of a prospective study designed to examine the effect of maxillary fixation methods on postoperative stability. The purpose of this study was to evaluate the stability of Le Fort I osteotomy stabilized with semirigid fixation of the maxilla (SRMF) or rigid fixation of the maxilla (RMF). All patients had skeletal Class III malocclusion and underwent bimaxillary surgery (Le Fort I maxillary advancement with or without superior repositioning and bilateral sagittal split osteotomies of the mandible). Standardized cephalometric analysis was performed on serial radiographs of 42 patients immediately before surgery, 1 week after surgery, after release of fixation, and 1 year postoperatively. The patients were randomized into 2 treatment groups: 23 patients received RMF (group A), and 19 patients received SRMF (group B). Within the groups, patients showed good stability with regard to their baseline characteristics. To show the therapeutic equivalence of the 2 treatments, analysis of the recorded data followed the approach for an equivalence trial. The mean surgical advancement was 5.34 +/- 1.50 mm for group A and 4.51 +/- 1.37 mm for group B. The mean amount of postsurgical relapse was 0.98 +/- 1.27 mm for group A and 0.30 +/- 1.04 mm for group B. Group A patients experienced 93% of their relapse (0.92 mm) during fixation, while group B patients experienced 96% of their relapse (0.29 mm) after release of fixation. RMF provided better stability than SRMF for all maxillary landmarks in the vertical plane. All considered points both in horizontal and vertical plane exhibited full equivalence for 95% confidence intervals, which seems to indicate equivalent stability between the surgical procedures.     

Postoperative stability following maxillary downward movement with Le Fort I inclined osteotomy at the lateral nasal cavity wall

Downward movement of the maxilla is regarded as one of the less stable long-term orthognathic surgical procedures. To increase postoperative stability with direct bone contact, the conventional Le Fort I osteotomy was modified with an inclined osteotomy at the lateral nasal cavity wall. The aim of this study was to evaluate the postoperative stability of the new method for Le Fort I inclined osteotomy for downward maxillary movement.The study included 27 patients with anterior vertical deficiency of the maxilla who underwent Le Fort I inclined osteotomy for downward maxillary movement. Patients were classified into two groups according to the amount of downward movement. The amounts of relapse (cephalometric changes) of the two groups were compared and statistically analyzed.The mean amount of relapse was about 1 mm. The tendency of relapse was not increased by a large initial downward movement with Le Fort I inclined osteotomy. Le Fort I inclined osteotomy was used safely for downward movement in order to increase bone height at the piriform aperture area and resulted in direct bone contact, suggesting it is a useful technique for maintaining postoperative stability. A further study with a larger number of patients is necessary.     

Stability of skeletal Class III malocclusion after combined maxillary and mandibular procedures

The aim of this study was to evaluate the skeletal stability and time course of postoperative changes after surgical correction of skeletal Class III malocclusion. Combined maxillary and mandibular procedures were performed in 40 consecutive patients. Bilateral sagittal split osteotomy stabilized with wire osteosynthesis for mandibular setback and low-level Le Fort I osteotomy stabilized with plates and screws for maxillary advancement were performed. Maxillomandibular fixation (MMF) was in place for 6 weeks. Lateral cephalograms were taken before surgery, immediately postoperatively, 8 weeks after surgery, and 1 year postoperatively. Patients were divided into 2 groups according to vertical maxillary movement at surgery: a maxilla-up group with upward movement of the posterior nasal spine of 2 mm or more (group 1, n = 22), and a minimal vertical change group with less than 2 mm of vertical repositioning (group 2, n = 18). The results indicate that surgical correction of Class III malocclusion with combined maxillary and mandibular osteotomies appears to be fairly stable. One year postsurgery, maxillary stability was excellent, with a mean horizontal relapse at point A that represented 10.7% of maxillary advancement in group 1 and 13.4% in group 2. In the vertical plane, maxillary stability was also excellent, with a mean of 0.18 mm of superior repositioning at point A for group 1 and 1.19 mm for group 2. The mandible relapsed a mean of 2.97 mm horizontally at pogonion in group 1 (62% of mandibular setback) and 3.41 mm (49.7% of setback) in group 2. Bilateral sagittal split osteotomy with wire osteosynthesis and MMF was not as stable as maxillary advancement and accounted for most of the total horizontal relapse (almost 85%) observed. A trend to relapse was observed for maxillary advancement greater than 6 mm, while the single variable accounting for mandibular relapse in group 1 was the amount of surgical setback. Clockwise rotation of the ascending ramus at surgery was not correlated with mandibular relapse in relation to the type of fixation performed and therefore does not seem to be responsible for relapse.     

The stability of Le Fort I advancement osteotomies using bone plates without bone grafts

The stability of Le Fort I advancement osteotomies using 4 "Champy" stainless steel mini plates without bone grafts was studied. Eleven consecutive patients, 3 of whom had cleft lips and palates were evaluated retrospectively. Seven patients had bimaxillary procedures. Cephalometric radiographs were taken preoperatively, immediately after operation and at least six months later. The mean maxillary advancement in the horizontal direction was 3.7 mm. The radiographs were traced and the results were subjected to a statistical analysis. No significant relapse was found.     

Stability of simultaneous maxillary and mandibular osteotomy for treatment of class III malocclusion: an analysis of three-dimensional cephalograms.

PURPOSE: The current investigation was undertaken to study the three-dimensional (3-D) stability of simultaneous maxillary advancement and mandibular setback using rigid fixation. The study also aimed to analyse the factors involved in postsurgical relapse by evaluation of changes in various parameters. PATIENTS: Twenty-five cases were evaluated of simultaneous Le Fort I maxillary advancement and mandibular setback using rigid fixation. METHODS: Preoperative, immediate and 6-month postoperative skeletal and dental changes were analysed using 3-D cephalograms obtained from biplanar stereoradiography. Maxillary fixation screws were used as landmarks to evaluate postoperative stability. RESULTS: The mean maxillary advancement was 3.7 mm. Relapse in the sagittal, vertical, and transverse planes was not detectable in the maxilla (p > 0.05). However, for an average mandibular setback of 5.7 mm, mean mandibular relapse was 1.1 mm or 19.3% anteriorly (p < 0.05). Surgical or postsurgical skeletal changes in the maxilla had no detectable influence on mandibular relapse (p > 0.05). Vertical alterations of the facial skeleton achieved surgically predicted the mandibular relapse (R2 = 0.27, p < 0.05). CONCLUSION: Maxillary advancement and vertical changes of +/- 2 mm did not influence the postoperative stability of the mandible. Relapse of the mandible seems to be influenced mainly by the amount and direction of the surgical alteration of mandibular position.     

Factors related to relapse after Le Fort I maxillary advancement osteotomy in patients with cleft lip and palate.

OBJECTIVE: To identify factors associated with relapse after maxillary advancement in cleft lip and palate patient. SUBJECTS: Seventy-one cleft lip and palate patients underwent Le Fort I maxillary advancement osteotomy between 1988 and 1998, and 58 patients (42 unilateral cleft and 16 bilateral cleft) with complete data were investigated for relapse by clinical and cephalometric analysis. The clinical follow-up period ranged from 1.5 to 8.5 years (mean 2.5 years). RESULTS: Horizontal advancement averaged 6.9 mm. There was a significant correlation between surgical movement and postoperative relapse in both the horizontal and vertical planes. In vertical repositioning, 15 patients had maxillary intrusion and 31 had inferior repositioning. There was a significant difference between the intrusion group and the inferior repositioning group. There was a significant correlation between surgical and postoperative rotation regardless of the direction. Other factors were evaluated by the horizontal relapse rate. Type of cleft and the rate of relapse were statistically associated. A relapse was more likely to occur in patients with bilateral cleft. There were no significant associations with the rate of relapse in type of operations or previous alveolar bone grafting. There was no significant correlation between the rate of relapse and the number of missing anterior teeth, postoperative overbite and overjet, and age at operation. Four of 71 patients experienced major relapse, and 3 of them underwent jaw surgery again. CONCLUSIONS: Based on clinical and cephalometric analysis, two-jaw surgery should be performed in cases of severe maxillary hypoplasia, and overcorrection may be useful in inferior repositioning or surgical rotation. Special attention should be paid to the patient with bilateral cleft, multiple missing teeth, or shallow postoperative overbite.     

Stability after Le Fort I osteotomy in cleft lip and palate patients

Le Fort I osteotomies were performed in 20 patients with cleft lip and palate as a one-segment movement, and the fragments were fixed with miniplates without bone grafting. Tracings of preoperative and serial postoperative lateral cephalograms were used to determine changes in maxillary position. The posterior nasal spine, not subjected to extensive changes during surgical procedures and remodeling, was found to be the most reliable landmark for measuring maxillary advancement and stability. The mean maxillary advancement was 5.96 mm. Analysis did not reveal significant changes in linear and angular measurements from immediately postoperative to 6 months postoperative. A modest maxillary advancement by Le Fort I osteotomy, along with alleviation of palatal scar tissue tension and miniplate fixation, is a stable surgical method in patients with cleft lip and palate.     

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.     

Stability of maxillary advancement using rigid fixation and porous-block hydroxyapatite grafting: cleft palate versus non-cleft patients

This study was undertaken to evaluate the stability of maxillary advancement using bone plates for skeletal stabilization and porous block hydroxyapatite (PBHA) as a bone graft substitute for interpositional grafting in cleft and non-cleft patients. The records of 74 patients (41 females, 33 males) who underwent Le Fort I maxillary advancement using rigid fixation and PBHA interpositional grafting were evaluated retrospectively. All patients also underwent simultaneous sagittal split mandibular ramus osteotomies. Patients were divided into 2 groups for study purposes: group 1 consisted of 17 cleft palate patients and group 2 consisted of 57 non-cleft patients. Each group was further subdivided into 2 subgroups based on the concurrent vertical positioning of the maxillary incisors: groups 1a and 2a, where the maxilla underwent 3 mm or more of inferior repositioning, and groups 1b and 2b, where the maxilla underwent minimal vertical change (< or = 1 mm). Presurgery, immediate postsurgery, and longest follow-up lateral cephalometric tracings were superimposed and analyzed to calculate surgical change and long-term stability of results by assessing horizontal and vertical changes at point A, incisor superius, and the mesial cusp tip of maxillary first molar. The average follow-up time in group 1 was 37.9 months (range 12 to 136) and in group 2 was 28.77 months (range 17 to 88). Average maxillary advancement at point A was: group 1a, 5.4 mm; group 1b, 5.25 mm; group 2a, 5.48 mm; group 2b, 5.46 mm. Average relapse at point A was: group 1a, -0.75 mm; group 1b, -1 mm; group 2a, -0.47 mm; group 2b, -0.48 mm. Average horizontal and/or vertical relapse at the central incisors and first molars was 1 mm or less in group 1 and less than 0.5 mm in group 2. Although there was a slightly greater relapse in group 1, no statistically significant difference was observed between the groups. Maxillary advancement with Le Fort 1 osteotomies using rigid fixation and interpositional PBHA grafting during bimaxillary surgery is a stable procedure with good predictability in cleft and non-cleft patients, regardless of the direction of vertical maxillary movement.     

Does platelet-rich fibrin increase stability of the maxilla following Le Fort I osteotomy? A single-blind clinical trial study

This single-blind clinical trial study aimed to assess the efficacy of platelet-rich fibrin (PRF) in increasing stability following Le Fort I osteotomy for maxillary advancement. Patients who underwent Le Fort I osteotomy for maxillary advancement were assigned randomly into two groups: in group 1 (the study group, n = 22) PRF was placed in the osteotomy sites following fixation, while no PRF was used in group 2 (the control group, n = 22). Lateral cephalograms obtained preoperatively (T0), immediately after surgery (T1), and 1 year after surgery (T2) were compared between the two groups, and the amount of relapse was determined. The amount of maxillary change (relapse) at the A point in relation to the x-axis was 0.45 ± 0.67 mm in group 1 and 1.86 ± 0.56 mm in group 2. There was a significant difference in mean relapse in relation to the x-axis between the two groups 12 months after osteotomy (p < 0.001). The mean maxillary change (relapse) in relation to the y-axis was 0.77 ± 1.15 mm in group 1 and 2.25 ± 1.22 mm in group 2. Analysis of the data demonstrated a significant difference in mean relapse in relation to the y-axis between the two groups (p < 0.001). PRF may enhance the stability of the maxilla following Le Fort I osteotomy. Based on the results of this study the administration of PRF should be considered whenever possible.     

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.     

Maxillary stability following Le Fort I osteotomy using prebent plates and wire fixation in patients undergoing surgery for OSAS

The purpose of this study was to analyze the stability of Le Fort I maxillary advancement in the vertical and horizontal directions using a combination of wire and rigid fixation in patients undergoing surgery to treat obstructive sleep apnea (OSA). Wire osteosynthesis can be performed quicker and at a reduced cost.The lateral cephalograms of 21 patients were evaluated preoperatively (T0), immediately postoperatively (T1), and at least 6 months postoperatively (T2). Four cephalometric points were used to measure movement in the horizontal and vertical directions. Mean values were determined, and data were statistically analyzed by ANOVA to determine differences between time points.Of the four points analyzed, the average maxillary advancement in the horizontal direction was 7.48 mm and the relapse was 0.56 mm with absence of statistically significant differences between the measurements taken (T1) and (T2). There was a 5% probability of error in the vertical movements at the points I and posterior nasal spine.The combination of two pre-bent plates in piriform aperture with osteosynthesis using surgical steel wires in the zygomatic buttress in patients undergoing maxillary surgery for OSA stabilized the large horizontal maxillary advancements and enhanced vertical stability in the first molar and A point regions.     

Soft tissue profile changes after Le Fort I osteotomy in UCLP patients.

The changes in soft tissue profile after Le Fort I osteotomy were evaluated cephalometrically in 38 consecutive UCLP patients (25 males, 13 females) operated on between 1987 and 1995. Mean age at operation was 23.5 years. The one-piece Le Fort I osteotomy was fixed with titanium plates and the osteotomy site was bone grafted. Neither intermaxillary fixation nor occlusal splints were used postoperatively. Soft tissue changes were analyzed both horizontally and vertically by cephalograms taken shortly before surgery, 6 months and 1 year postoperatively. The mean maxillary skeletal advancement (point A) during surgery was 3.8 mm and mean vertical lengthening 4.4 mm. One year postoperatively the horizontal change in the upper lip profile (point a) was 80% of the skeletal change. Vertically, the soft tissue change in the upper lip was smaller 40%, but increased significantly (to 58%) if V-Y plasty was used. The V-Y plasty also increased the anteroposterior thickness of the upper lip. No significant soft tissue changes were observed between 6 months and 1 year postoperatively.     

Skeletal stability following maxillary impaction and mandibular advancement

The purpose of this study was to retrospectively evaluate the stability of combined Le Fort I maxillary impaction and mandibular advancement performed for the correction of skeletal Class II malocclusion. Twenty-nine patients, mean age 22.6 years, underwent bimaxillary surgery with rigid internal fixation. Standardised cephalometric analyses were performed using serial lateral cephalometric radiographs. The post-surgical follow-up was a minimum of 12 months, with a mean of 25.2 months. The maxilla was impacted by a mean of 4.3 +/- 3.3 mm, and horizontally advanced by a mean of 2.6 +/- 2.3 mm. The results demonstrated that the maxilla tended to move anteriorly and inferiorly but this was not significant in either horizontal or vertical planes (P > 0.05). The mean advancement of the mandible, at menton, was 10.7 +/- 5.6 mm, and in 14 cases (48.2%) menton was advanced greater than 10 mm. In 34.7% of the patients the mandible underwent posterior movement between 2 and 4 mm. In the vertical plane, gonion moved superiorly by a mean of 2.7 +/- 3.6 mm which was significant. Significant mandibular relapse was found to have occurred in five female patients, with high mandibular plane angles who had undergone large advancements of greater than 10 mm. In conclusion, the majority of patients undergoing bimaxillary surgery for the correction of skeletal Class II malocclusions maintained a stable result. However, a small number of patients, exhibiting similar characteristics, suffered significant skeletal relapse in the mandible secondary to condylar remodelling and/or resorption.