Effect of mandibular setback via bilateral sagittal split ramus osteotomy on transverse displacement of the proximal segment.

PURPOSE: The purpose of this study was to evaluate if a correlation exists between: a) transverse changes in the proximal segments because of mandibular setback surgery and b) postsurgical horizontal relapse of the mandible. PATIENTS AND METHODS: A total of 42 patients underwent bilateral sagittal split ramus osteotomy setback with rigid fixation and Le Fort I osteotomy performed by 1 surgeon between 1986 and 2000. The radiographic material for this study consisted of posteroanterior and lateral cephalometric radiographs for each patient taken preoperatively (T1), early postoperatively (T2), and late postoperatively (T3). Twenty-four of the 42 identified patients had T1, T2, and T3 radiographs, while the remainder of the patients had only T1 and T2 radiographs available. The posteroanterior radiographs were used to evaluate the angulation of the proximal segment and the intergonial width. RESULTS: Statistically significant increases in intergonial width and proximal segment angulation occurred from T1 to T2. In fact, all 42 patients had an increased intergonial width from T1 and T2. From T2 to T3, most patients underwent some relapse in their transverse dimension changes (21 of 24 patients had a decrease in their intergonial width). Overall, the intergonial width and the proximal segment angulations were significantly increased from T1 to T3. However, there was no significant correlation between the amount of transverse displacement of the proximal segment and horizontal postsurgical relapse of the mandible. CONCLUSION: The results show that statistically significant changes in the transverse width and angulation between proximal segments occur in patients undergoing bilateral sagittal split ramus osteotomy for mandibular setback with rigid fixation. However, the magnitude of the changes was small, and it is still uncertain as to whether these changes are of any clinical significance.     

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.     

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.     

Transverse displacement of the proximal segment after bilateral sagittal osteotomy.

PURPOSE: The aim of the present investigation was to evaluate the transverse displacement of the proximal segment and ramus rotation after a bilateral sagittal osteotomy (BSO) with rigid internal fixation (RIF) using bicortical LAG screws. PATIENTS AND METHODS: We conducted a retrospective review of 37 patients (14 males and 23 females, age range of 14 to 55 years) who underwent a mandibular advancement with BSO and RIF. Posteroanterior and lateral cephalometric radiographs were obtained 1 to 8 weeks before and 1 to 4 weeks after surgery. The transverse displacement and angulation of the proximal segments after surgery were measured on posteroanterior radiographs, using the best-fit method. The amount of mandibular advancement was compared with the amount of transverse displacement of the proximal segments. RESULTS: In the 1 to 4-week postoperative period after a BSO, 36 of 37 subjects showed an increased transverse intergonion distance (5.6 mm) (P <.0001) and 35 of 37 patients showed an increased transverse interramus width (3.3 mm) (P <.0001). No correlation was found between mandibular advancement and transverse displacement of the proximal segment. CONCLUSIONS: The study results indicate that transverse displacements of the proximal segments occur with BSO and RIF. The clinical impact on temporomandibular joint symptomatology or surgical relapse with such displacement was not assessed in the study. Future studies that address these issues may help to determine whether there is an association between proximal segment displacement and surgical relapse, temporomandibular dysfunction, or both.     

Skeletal and dento-alveolar stability after surgical-orthodontic treatment of anterior open bite: a retrospective study.

The aim of this investigation was to assess skeletal and dento-alveolar stability after surgical-orthodontic correction of skeletal anterior open bite treated by maxillary intrusion (group A) versus extrusion (group B). The cephalometric records of 49 adult anterior open bite patients (group A: n = 38, group B: n = 11), treated by the same maxillofacial surgeon, were examined at different timepoints, i.e. at the start of the orthodontic treatment (T1), before surgery (T2), immediately after surgery (T3), early post-operatively (+/- 20 weeks, T4) and one year post-operatively (T5). A bimaxillary operation was performed in 31 of the patients in group A and in six in group B. Rigid internal fixation was standard. If maxillary expansion was necessary, surgically assisted rapid palatal expansion (SRPE) was performed at least 9 months before the Le Fort I osteotomy. Forty-five patients received combined surgical and orthodontic treatment. The surgical open bite reduction (A, mean 3.9 mm; B, mean 7.7 mm) and the increase of overbite (A, mean 2.4 mm; B, mean 2.7 mm), remained stable one year post-operatively. SNA (T2-T3), showed a high tendency for relapse. The clockwise rotation of the palatal plane (1.7 degrees; T2-T3), relapsed completely within the first post-operative year. Anterior facial height reduction (A, mean -5.5 mm; B, mean -0.8 mm) occurred at the time of surgery. It can be concluded that open bite patients, treated by posterior Le Fort I impaction as well as with anterior extrusion, with or without an additional bilateral sagittal split osteotomy (BSSO), one year post-surgery, exhibit relatively good clinical dental and skeletal stability.     

Positional changes of the masseter and medial pterygoid muscles after surgical mandibular advancement procedures: an MRI study

This study evaluated whether surgical mandibular advancement procedures induced a change in the direction and the moment arms of the masseter (MAS) and medial pterygoid (MPM) muscles. Sixteen adults participated in this study. The sample was divided in two groups: Group I (n=8) with a mandibular plane angle (mpa) <39° and Group II (n=8) with an mpa >39°. Group I patients were treated with a bilateral sagittal split osteotomy (BSSO). Those in Group II were treated with a BSSO combined with a Le Fort I osteotomy. Pre- and postoperative direction and moment arms of MAS and MPM were compared in these groups. Postsurgically, MAS and MPM in Group II showed a significantly more vertical direction in the sagittal plane. Changes of direction in the frontal plane and changes of moment arms were insignificant in both groups. This study demonstrated that bimaxillary surgery in patients with an mpa >39° leads to a significant change of direction of MAS and MPM in the sagittal plane.     

Simultaneous hybrid of maxillary Le Fort I halo distraction and mandibular set-back for patients with severe cleft jaw deformity

One of the surgical tactics and retrospective chart review of clinical cases are described for severe maxillo-mandibular discrepancy. The recently developed Le Fort I Halo distraction combined with mandibular sagittal splitting osteotomy is initially carried out simultaneously. Materials include six adult patients revealing severe jaw deformity with mandibular prognathism somehow ranging from 17-19 years of age. The required adjustment of the maxillo-mandibular discrepancy ranged from 14-23 mm to obtain the preferred occlusion. The simultaneous combination of over 10-mm maxillary Le Fort I Halo distraction with mandibular set-back secured rigidly by sagittal splitting was accomplished. The amount of mandibular set-back ranged from 4-6 mm. The amount of maxillary Le Fort I halo distraction ranged from 10-17 mm (Table I). The retention period of the halo brace was 21-22 days. In addition, the Delair type of face mask was used for 3-4 months as a night splint for consolidation after removal of the halo brace. Satisfactory maxillary distraction and mandibular set-back as planned preoperatively was obtained in all six cases. No particular postoperative complications were noticed. Compared with standard Le Fort I advancement for cleft patients, more advancement can be obtained easily with halo distration, particularly in cases where a large amount of advancement > 10 mm is required. This combination is worthwhile for a severe cleft jaw deformity, and is an alternative for standard double jaw osteotomy.     

Postsurgical stability of oropharyngeal airway changes following counter-clockwise maxillo-mandibular advancement surgery.

PURPOSE: This study evaluated oropharyngeal airway changes and stability following surgical counter-clockwise rotation and advancement of the maxillo-mandibular complex. METHODS AND PATIENTS: Fifty-six adults (48 females, 8 males), between 15 and 51 years of age, were treated with Le Fort I osteotomies and bilateral mandibular ramus sagittal split osteotomies to advance the maxillo-mandibular complex with a counter-clockwise rotation. The average postsurgical follow-up was 34 months. Each patient's lateral cephalograms were traced, digitized twice, and averaged to estimate surgical changes (T2-T1) and postsurgical changes (T3-T2). RESULTS: During surgery, the occlusal plane angle decreased significantly (8.6 +/- 5.8 degrees ) and the maxillo-mandibular complex advanced and rotated counter-clockwise. The maxilla moved forward (2.4 +/- 2.7 mm) at ANS and the mandible was advanced 13.1 +/- 5.1 mm at menton, 10 +/- 4.4 mm at point B, and 6.9 +/- 3.7 mm at lower incisor edge. Postsurgical hard tissue changes were not statistically significant. While the upper oropharyngeal airway decreased significantly (4.2 +/- 3.4 mm) immediately after surgery, the narrowest retropalatal, lowest retropalatal airway, and the narrowest retroglossal airway measurements increased 2.9 +/- 2.7, 3.7 +/- 3.2, and 4.4 +/- 4.4 mm, respectively. Over the average 34 months postsurgical period, upper retropalatal airway increased 3.9 +/- 3.7 mm, while narrowest retropalatal, lowest retropalatal airway, and narrowest retroglossal airway remained stable. Head posture showed flexure immediately after surgery (4.8 +/- 5.9 degrees ) and extension postsurgically (1.6 +/- 5.6 degrees ). CONCLUSION: Maxillo-mandibular advancement with counter-clockwise rotation produces immediate increases in middle and lower oropharyngeal airway dimensions, which were constrained by changes in head posture but remain stable over the postsurgical period. The upper oropharyngeal airway space increased only on the longest follow-up.     

Stability after rigid fixation of simultaneous maxillary impaction and mandibular advancement osteotomies

The purpose of this study was to investigate the short- and long-term stability of bimaxillary surgery following LeFort I (LF-1) impaction with simultaneous bilateral sagittal split ramus osteotomy (BSSO) and mandibular advancement using the technique of rigid internal fixation (RIF). In order to assess the postoperative maxillary and mandibular movement pattern in 26 patients with vertical maxillary excess and mandibular deficiency, cephalograms were taken immediately preoperatively, and 1 week, 2 months, and 1 year after surgery. With paired t-test showing no statistically significant postoperative change for the point A of the maxilla from immediate postsurgery to longest follow-up (P> 0.05), the used technique of "RIF LF-I impaction and RIF BSSO advancement" tended to render excellent postsurgical stability in the horizontal (0.1+/-0.8mm mean posterior movement) and vertical (0.1+/-0.5mm mean inferior movement) direction. There was no instance of maxillary relapse of >2mm. Regarding mandibular BSSO advancement, the point B showed a significant vertical upward movement (1.6+/-1.2mm) (P< 0.001) and a slight horizontal forward movement (0.3+/-2.0mm) (P> 0.05) at 1-year follow-up. The incidence of posterior relapse of >2mm accounted for 11.5%. The data confirm the concept that the bimaxillary approach of "LF-I impaction and BSSO advancement" using the described technique of RIF is a stable procedure in the treatment of open bite patients classified as vertical maxillary excess in combination with mandibular deficiency.     

Effect of modified bilateral sagittal split osteotomy on inferior alveolar nerve neurosensory disturbance

The aim of this study was to assess the occurrence of neurosensory disturbance of the inferior alveolar nerve (IAN) following modified mandibular bilateral sagittal split osteotomy (BSSO) that preserves the mandibular inferior border. All patients undergoing BSSO, associated or not with a Le Fort I osteotomy (performed by the same senior operator) between January 2018 and December 2019, were eligible. The modified BSSO consists of a modification of the technique described by Epker: the bony section of the buccal cortex stops 3-4 mm above the basal mandibular edge. While respecting the basilar border, sectioning is then performed up to the gonial angle where bicortical section is finally performed. Sensibility of the labial and chin area was evaluated immediately postoperatively, and at six months and two years of follow up. A total of 140 eligible patients underwent the modified BSSO between January 2018 and December 2019, and 72 were included. Hypoaesthesia was found in 81.9% of the patients (59/72 patients) at initial evaluation. It decreased to 45.8% (33/72 patients) at the six-month examination and to 12.5% (9/72 patients) at the last examination. Four bad splits were recorded. The modified BSSO preserves the inferior border of the mandible and maintains the IAN in the lingual fragment. There is no need to release the IAN, hence its manipulation is reduced and the incidence of IAN postoperative hypoaesthesia is also reduced.     

Soft tissue changes of the upper lip associated with maxillary advancement in obstructive sleep apnea patients.

PURPOSE: This retrospective study evaluated the horizontal and vertical soft tissue changes that occur with maxillary advancement surgery with a Le Fort I osteotomy with concomitant anatomic reorientation of the nasolabial musculature. SUBJECTS AND METHODS: Fifteen OSA patients who underwent maxillary advancement with a Le Fort I osteotomy without adjunctive nasal soft tissue procedures were studied after a minimum of 8 months of follow-up. The V-Y technique was used to close the maxillary vestibular incision. Only cases with minimal vertical movement (< 3.5 mm) in which no orthodontics were used were included. The average maxillary advancement was 8.0 +/- 2.5 mm, measured at the upper incisor (UPI) and the average vertical movement was 0.7 +/- 1.8 mm. The horizontal and vertical soft tissue change in subnasale (SN), labrale superiorus (LS), superior stomion (SS), nasal tip (NT), nasolabial angle (NLA), and lip length were measured in each patient and correlated with hard tissue measurements at anterior nasal spine (ANS) and UPI. The effect of lip thickness on these soft tissue changes also was evaluated. RESULTS: Using mean data, the horizontal soft-to-hard-tissue ratio for LS to UPI was 0.80:1, with a concomitant vertical (superior) soft tissue change to hard tissue advancement of 0.16:1. Lip length did not change significantly. All patients except 1 showed a slight decrease in nasolabial angle. The average decrease was 5 (range, -10 to +7 ). There was no statistically significant correlation between the degree of change in NLA and the amount of maxillary advancement. CONCLUSION: This study showed that advancement of the maxilla when controlling vertical movement resulted in the a hard-to-soft-tissue ratio of LS:UPI of 0.80:1. NLA did not change significantly.     

The Anatomical Basis for Plate Fixation in BSSO to Minimize Condylar Torquing: A Comparative CT Study of Mandibular Advancement and Setback

IntroductionCondylar displacement after bilateral sagittal-split osteotomy (BSSO) occur in the sagittal plane as clockwise/counter-clockwise rotation of the ramus, in the coronal plane as medial/lateral inclination, or in the axial plane as medial/lateral condylar torquing. The purpose of this prospective CT study was to evaluate the role of plate fixation in minimizing condylar torquing or rotational changes in the axial plane.Materials and MethodsThis prospective study was carried out on 26 patients, 13 of whom underwent advancement BSSO and 13 setback BSSO, without maxillary LeFort I osteotomies. All mandibular movements were symmetrical. Fixation of the osteotomized segments was achieved with a single 4-hole plate and monocortical screws. In case of mandibular setbacks, a straight plate was used, whereas an inset-bent plate was used for advancements. Computed tomography scans were obtained preoperatively and postoperatively to measure condylar rotation or torqueing in the axial plane. An increase in condylar angle on axial slices was considered as lateral condylar torquing, whereas a decrease was considered as medial condylar torquingResultsA mean medial condylar torquing of 0.2° was noted postoperatively in case of setbacks (p > 0.05 not significant). This suggested minimal condylar torquing, indicating that the proximal and distal segments maintained contact at the anterior vertical osteotomy fixed with a straight plate. In case of advancements, a mean lateral condylar torquing of 2.2° was noted postoperatively (p < 0.005, highly significant). This suggested that the proximal segment flare at the anterior vertical osteotomy site was maintained by inset-bent plate fixation.ConclusionThe gaps between the proximal and distal segments created by mandibular advancement and setback should be maintained. An attempt to close these gaps, especially in mandibular advancement, will result in an unfavourable axial condylar torque. Consequently, the areas of bony contact between the proximal and distal osteotomy sites created by mandibular advancement and setback should be maintained as well.     

Static and dynamic loading of mandibular condyles and their positional changes after bilateral sagittal split advancement osteotomies

This study analysed the effects of change of direction of masseter (MAS) and medial pterygoid muscles (MPM) and changes of moment arms of MAS, MPM and bite force on static and dynamic loading of the condyles after surgical mandibular advancement. Rotations of the condyles were assessed on axial MRIs. 16 adult patients with mandibular hypoplasia were studied. The mandibular plane angle (MPA) was <39° in Group I (n=8) and >39° in Group II (n=8). All mandibles were advanced with a bilateral sagittal split osteotomy (BSSO). In Group II, BSSO was combined with Le Fort I osteotomy. Pre and postoperative moment arms of MAS, MPM and bite force were used in a two-dimensional model to assess static loading of the condyles. Pre and postoperative data on muscle cross-sectional area, volume and direction were introduced in three-dimensional dynamic models of the masticatory system to assess the loading of the condyles during opening and closing. Postsurgically, small increases of static condylar loading were calculated. Dynamic loading decreased slightly. Minor rotations of the condyles were observed. The results do not support the idea that increased postoperative condylar loading is a serious cause for condylar resorption or relapse.     

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.     

Soft tissue changes after mandibular setback and bimaxillary surgery in Class III patients

Objective:To evaluate the relationship between soft tissue and bone structure for Class III patients before and after bilateral sagittal split osteotomy (BSSO) and bimaxillary orthognathic surgery; to determine the impact of other factors on soft tissue change; and to evaluate correlations between thickness of tissue before surgery, SNA, SNB, and ANB angles, and soft tissue changes.Materials and Methods:The study included 78 Class III patients treated only with BSSO or with BSSO and Le Fort I osteotomy. Lateral cephalograms were taken before and 3 months to 1 year after surgery. After all points of the Zagreb82 and Legan and Burstone profile analysis were traced, the ratio of five soft tissue points before and after surgery was evaluated.Results:Soft tissue between points Sn and A and upper lip showed statistically significant changes for patients treated with bimaxillary surgery and BSSO. Only gender had an influence on soft tissue change. The correlation between soft tissue thickness and changes after surgery was significant. A change in SNB angle correlated with upper lip thickness for patients treated with BSSO but not for patients treated with BSSO and Le Fort I. SNA angle changes correlated with soft tissue changes between points Sn and A.Conclusion:Results of this study show soft tissue changes after BSSO and BSSO and Le Fort I and eliminate the deficiencies that were indicated in the meta-analysis of soft tissue changes from a previous study.     

The stability of bilateral sagittal ramus osteotomy and vertical ramus osteotomy after bimaxillary correction of class III malocclusion

Introduction

The purpose of this retrospective cephalometric study was to compare the stability of bilateral sagittal split osteotomy (BSSO) with extra-oral vertical ramus osteotomy (VRO) after correction of class III malocclusion by means of bimaxillary orthognathic surgery.

Methods

The sample comprised 51 consecutively treated patients, 38 females and 13 males, with a mean age of 19.1 years. All had a one-piece Le Fort I osteotomy with maxillary advancement and mandibular setback. VRO was performed in 30 cases, and BSSO was performed in 21 cases. Lateral cephalograms were obtained before surgery, within 1 week of surgery and 1 year after surgery.

Results

The mean forward movement of the maxilla was 5.6 mm in both groups (p < 0.001). The mean horizontal surgical change in the VRO group was 4.4 mm (p < 0.001), and in the BSSO group it was 5.4 mm (p < 0.001). In the VRO group, the horizontal relapse was 1.2 mm (p < 0.001), and in the BSSO group, it was 1.4 mm (p < 0.001).

Conclusion

There was no difference in the stability between the BSSO and VRO groups. The average relapse in the whole sample was 26% of the surgical movement.     

Effect of Le Fort III osteotomy on mandibular growth in patients with Crouzon and Apert syndromes

Midface advancement by Le Fort III osteotomy is a common procedure in craniofacial surgery. However, little data exist concerning the effect of midface advancement on mandibular growth. This is a retrospective study of 38 patients from two craniofacial centers who had Le Fort III osteotomy. The aims of this investigation were to document the size and shape of the mandible in Crouzon and Apert syndromes and to determine the effect on these parameters of downward and forward movement of the midface. The syndrome patients had increased gonial angle, increased MP-SN, increased ramus height, and increased ratio of ramus height to body length when compared with normal standards. Patients operated during growth and those operated when growth was completed had similar mandibular size and shape indicating that Le Fort III osteotomy had no measurable effect on these parameters. Inclination of the mandible to the anterior cranial base was increased by the operation and remained unchanged during the follow-up period. The results of this study indicate that the size and morphology of the mandible are similar in Crouzon and Apert syndromes. The pattern of growth is more vertical in the syndrome patients than in normals. Le Fort III osteotomy in growing children does not result in altered mandibular size and shape despite backward rotation of the mandible as a result of midface advancement.     

Two-stage orthognathic treatment of severe class III malocclusion: report of a case

We report a two-stage orthognathic operation for a 16-year-old boy with a repaired isolated cleft palate. He had a severe class III malocclusion with an overjet of 20.4 mm. In the first stage, we did an anterior subapical segmental osteotomy with symphyseal ostectomy to reposition the mandibular anterior segment posteriorly and to reduce the transverse width of the mandible. During the second stage, we did a maxillary advancement by Le Fort I osteotomy, mandibular set-back by sagittal split osteotomy, reduction genioplasty, and shortening of the tongue. This unique two-stage surgical and orthodontic treatment considerably improved his overall facial aesthetics and occlusion.     

Le FortⅠ型骨切开上颌骨整体后退术矫治骨性Ⅱ类上颌骨前突畸形

目的：探讨Le Fort Ⅰ型骨切开（Le Fort Ⅰ osteotomy）上颌骨整体后退术在矫治骨性Ⅱ类上颌骨前突畸形中的价值。方法：对16例骨性Ⅱ类上颌前突患者（上颌骨前突伴下颌骨后缩14例,其中同时伴颏后缩6例;单纯上颌骨前突2例）进行外科-正畸联合治疗。患者治疗前头影测量∠ANB为7.0°～13.1°,平均9.3°。行Le Fort Ⅰ型骨切开上颌骨整体后退术,其中14例同期行双侧下颌支矢状骨劈开术（bilateral sagittal split ramus osteotomy,BSSRO）前移下颌骨,6例行颏成形术（genioplasty）前移颏部。结果：本组行LeFortⅠ型骨切开上颌骨整体后退4～8mm,14例BSSRO下颌骨前移4～7mm,6例颏成形术颏前移6～8mm。1例一侧腭降动脉术中损伤断裂,经结扎处理,无感染及骨块坏死。16例患者伤口均一期愈合。术后及正畸结束后∠ANB为1.6°～3.5°,平均2.9°。结束治疗后随访6～24个月,牙弓形态及[牙合]曲线正常,牙排列整齐,咬合关系良好,外形明显改善,疗效满意。结论：对于骨性Ⅱ类上颌骨前突畸形患者,Le Fort Ⅰ型骨切开上颌骨整体后退术是一种安全、合理、有效的正颌外科术式。     

Le Fort Ⅰ型截骨术对上颌后缩患者腭咽部结构影响的研究

目的:探讨上颌Le Fort Ⅰ型截骨术对上颌后缩患者腭咽部结构的影响.方法:选择2007-2009年行上颌Le Fort Ⅰ型截骨术的上颌后缩伴随下颌前突患者42例(男20例,女22例,平均年龄21.6岁),所有患者在术前、术后1周、术后1年拍摄静止位头颅定位侧位片,然后对腭咽部软组织结构指标进行测量分析.结果:上颌...