The stability of facial osteotomies. Part 5. Maxillary advancement with miniplate and screw fixation

Surgical repositioning of the dento-skeletal components of the middle-third of the 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 postsurgical period.
This paper examines the short-term (six weeks postoperative) and long-term (12 months postoperative) horizontal skeletal stability of Le Fort I maxillary advancement in 15 patients. The mean horizontal advancement of the maxilla was 8.76 ± 0.99 mm. Six weeks later, a mean relapse of 0.22 ± 0.19 mm was identified. The mean relapse at long-term follow-up was 0.61 ± 0.26 mm (6.96%).
These results indicate that rigid miniplate and screw fixation of Le Fort I osteotomy undertaken to correct horizontal mid-dentofacial deficiency is both statistically and surgically predictable and stable when reviewed up to twelve months after surgery.     

The stability of double jaw surgery: A comparison of rigid versus wire fixation

The subjects of this study were 35 patients who underwent simultaneous surgery for superior repositioning of the maxilla and advancement of the mandible. They were studied cephalometrically for a comparison of the postsurgical stability of two commonly used fixation techniques: (1) rigid fixation with bone plates and (2) skeletal-wire fixation. One surgeon performed the operations on all 35 patients, and both groups were studied for an average of 15 months after surgery. Results showed that, although the maxilla remained relatively stable after surgery with both fixation techniques, rigid fixation tended to improve stability, primarily by eliminating relapse in excess of 2 mm. Mandibular stability was much greater with rigid fixation: the amount of relapse of the horizontal projection of B point with this method was 6%, while in the skeletal-wire sample it was 26%. Increased rotational stability between the proximal and distal segments of the mandible appeared to be a major factor in the improved overall stability of the rigid-fixation sample. The amount of mandibular relapse was found to be correlated to the amount of advancement in the wire-fixation sample, but not in the rigid-fixation sample.     

A comparative study of skeletal and dental stability between rigid and wire fixation for mandibular advancement

This study examined the skeletal and dental stability after mandibular advancement surgery with rigid or wire fixation for up to 2 years after the surgery. Subjects for this multisite, prospective, randomized, clinical trial were assigned to receive rigid (n = 64) or wire (n = 63) fixation. The rigid cases received three 2-mm bicortical position screws bilaterally and elastics; the wire fixation subjects received inferior border wires and 6 weeks of skeletal maxillomandibular fixation with 24-gauge wires. Cephalometric films were obtained before surgery, and at 1 week, 8 weeks, 6 months, 1 year, and 2 years after surgery. Skeletal and dental changes were analyzed using the Johnston's analysis. Before surgery both groups were balanced with respect to linear and angular measurements of craniofacial morphology. Mean anterior advancement of the mandibular symphasis was 5.5 mm (SD, 3.2) in the rigid group and 5.6 mm (SD, 3.0) in the wire group. Two years after surgery, mandibular symphasis was unchanged in the rigid group, whereas the wire group had 26% of sagittal relapse. Dental compensation occurred to maintain the corrected occlusion, with the mandibular incisor moving forward in the wire group and posteriorly in the rigid group. However, at 2 years after surgery, when most subjects were without braces, the overjet and molar discrepancy had relapsed similarly in both groups.     

Outcome of early rigid fixation and removal of rigid external distraction system after distraction osteogenesis of the midface

After distraction osteogenesis of the midface using a rigid external distraction (RED) system, there is a high possibility that a relapse might occur due to an incomplete fixation during the consolidation period, and it is uncomfortable for the patients to wear a head frame for 2 to 3 months. There are also risks of trauma that are developing. To overcome these problems, we suggest the protocol of early rigid fixation, with excellent treatment outcomes and a review of literatures. Of 9 patients, Le Fort III osteotomy was completed in 2 patients with Crouzon disease, and a Le Fort I osteotomy was completed in 7 patients with a cleft lip and palate. Immediately after the distraction with RED was completed, the fixation was done using a miniplate. This was followed by the early removal of the RED system. In patients who underwent the current procedure, an analysis was performed for the degree and the duration of distraction and the period of use of the RED system. Then, the presence of relapse was examined. The mean degree of bone distraction was found to be 18.05 mm (range, 9-31.5 mm). The mean period of wearing RED system was 29.78 days (range, 21-43 days). Thereafter, the mean follow-up period was 13 months (range, 6 months to 3 years). The degree of accumulated relapse was found to be 1.7 mm (10%) on postoperative year 1, 2.4 mm (13.3%) on postoperative year 2, and 2.3 mm (14.6%) on postoperative year 3. With the concept of early rigid fixation, we were able to eliminate the disadvantages of distraction osteogenesis such as the long period of wearing a head frame, the delay of returning to society, and the inconvenience of patients. Moreover, early rigid fixation could decrease the need of overcorrection and the amount of relapses.     

Skeletal stability after mandibular advancement with rigid versus wire fixation.

PURPOSE: This study examined the stability of skeletal changes after mandibular advancement surgery with rigid or wire fixation up to 2 years postoperatively. PATIENTS AND METHODS: Subjects for this multisite, prospective, clinical trial received rigid (n = 78) or wire (n = 49) fixation. The rigid cases were fixed with three 2-mm bicortical position screws and 1 to 2 weeks of skeletal maxillomandibular fixation with elastics, and the wire fixation subjects were fixed with inferior border wires and had 6 weeks of skeletal maxillomandibular fixation with 24-gauge wires. Cephalometric radiographs were obtained before orthodontics, immediately before surgery, and at 1 week, 8 weeks, 6 months, 1 year, and 2 years after surgery. Linear cephalometric changes were referenced to a cranial base coordinate system. RESULTS: Before surgery, both groups were balanced with respect to linear and angular measurements of craniofacial morphology. Mean anterior sagittal advancement of the mandibular symphysis was 4.92 +/3.01 mm in the rigid group and 5.11 +/- 3.09 mm in the wire group, and the inferior vertical displacement was 3.37 +/- 2.44 in the rigid group and 2.85 +/- 1.78 in the wire group. The vertical changes were similar in both groups. Two years postsurgery, the wire group had 30% sagittal relapse of the mandibular symphysis, whereas there was no change in the rigid group (P < .001). Both groups experienced changes in the orientation and configuration of the mandible. CONCLUSIONS: Rigid fixation is a more stable method than wire fixation for maintaining mandibular advancement after sagittal split ramus osteotomy.     

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.     

A comparison of skeletal and dental changesbetween rigid and wire fixation for bilateral sagittal split osteotomy

For two years, this multisite prospective clinical trial examined longitudinalskeletal and dental changes after bilateral sagittal split osteotomy for mandibular advancement in which either rigid or wire fixation was used. Subjects in the rigid fixation group (n = 78) received 2-mm bicortical position screws, while the subjects in the wire fixation group (n = 49) received inferior border wires. Skeletal and dental changes were measured from cephalometric films taken immediately before surgery, one week after surgery, and at eight weeks, six months, one year, and two years after surgery. In both groups, the overbite and overjet increase with time, but were not different from each other. The B-point in the wire group progressively moved posteriorly, and at two years, it had relapsed 28%. In the rigid fixation group, there was a transient anterior movement of the B-point during the first six months and by two years after surgery, the B-point was unchanged from immediate post surgery. Dental changes occurred in both groups. These changes, however, were not able to accommodate the skeletal changes, resulting in similar increases in both overbite and overjet in both groups of patients. These results have implications for the orthodontists in management of the postmandibular advancement occlusion.     

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.     

Assessment of the stability of mandibular setback procedures with rigid fixation

The postsurgical changes associated with sagittal ramus osteotomy and mandibular setback stabilized with rigid fixation were evaluated. Lateral cephalometric radiographs of 25 individuals (11 males and 14 females) with a mean age of 23.4 years were evaluated presurgery, immediate postsurgery, and after a follow-up period of 7 to 42 months. The mean amount of surgical setback was 5.1 +/- 3.0 mm and the mean amount of postsurgical anterior movement was 0.51 +/- 1.04 mm, representing a 10% relapse of the original surgical correction. The postsurgical relapse of the mandible was not found to be related to the amount of surgical movement. Sixteen of the 18 cases that demonstrated anterior relapse moved forward between 0.5 and 1.5 mm. The amount of relapse was consistent and statistically significant (P less than .05), but small enough that it was not considered to be clinically significant. The findings of this study indicate that mandibular setback with a sagittal ramus osteotomy and its stabilization with rigid fixation appears to be a stable clinical procedure.     

翼外肌-髁突解剖复位内固定治疗髁突骨折的探讨

目的:探讨髁突骨折进行解剖复位和小型钛板坚强内固定的手术适应证、方法和治疗效果。方法:以髁头脱位骨折、髁颈和髁颈下骨折移位角度大于30°～45°、下颌支垂直高度降低超过4～5mm为适应证,对收治的23例28侧髁突骨折患者采用改良耳颞部"拐杖"型切口或颌后进路,行翼外肌-髁突解剖复位及张力带小型钛板坚强内固定。术后3～6个月复诊,检查面型、开口度、开口型、咬合关系、咀嚼力,并以此进行疗效评价。结果:所有患者面型对称,开口度较术前明显增大,开口型显著改变。2例术后错牙合患者经1周颌间牵引,恢复正常。影象学检查示髁突无移位,骨折无错位。钛板无移位,髁突表面无明显吸收现象。患者咀嚼有力。2例面瘫患者经治疗后3个月恢复。结论:选择合适病例,进行翼外肌-髁突开放性解剖复位固定,是一种既能恢复解剖形态又能恢复咀嚼功能的有效方法。     

Rigid versus wire fixation for mandibular advancement: Skeletal and dental changes after 5 years

The bilateral sagittal split osteotomy (BSSO) is the most common surgical procedure for the correction of mandibular retrognathism. Commonly, the proximal and distal segments are fixated together with either wire or rigid screws or plates. The purpose of this study was to compare long-term (5 years) skeletal and dental changes between wire and rigid fixation after BSSO. In this multisite, prospective, randomized clinical trial, the rigid fixation group received three 2-mm bicortical position screws, and the wire fixation group received inferior border wires and 6 weeks of skeletal maxillomandibular fixation with 24-gauge wires. Cephalometric films were obtained 2 weeks before surgery and at 1 week, 8 weeks, 6 months, 1 year, 2 years, and 5 years after surgery. Linear cephalometric changes were referenced to a cranial base coordinate system. Before surgery, both groups were comparable with respect to linear and angular measurements of craniofacial morphology. Both groups underwent similar surgical changes. Skeletal and dental movements occurred in both groups throughout the study period. Five years after surgery, the wire group had 2.2 mm (42%) of sagittal skeletal relapse, while the rigid group remained unchanged from immediately postsurgery. Surprisingly, at 5 years, both groups had similar changes in overbite and overjet. This was attributed to dental changes in the maxillary and mandibular incisors. Although rigid fixation is more stable than wire fixation for maintaining the skeletal advancement after a BSSO, the incisor changes made the resultant occlusions of the 2 groups indistinguishable.     

A 3-year evaluation of skeletal stability of mandibular advancement with rigid fixation

The postsurgical changes associated with mandibular advancements using the sagittal ramus osteotomy and rigid fixation were evaluated. This retrospective study was based on examination of lateral cephalometric radiographs of 19 individuals (16 females and 3 males) with a mean age of 26.6 years. These radiographs were evaluated presurgically, immediately postsurgery, and 3 years postsurgically (2 years, 9 months to 4 years, 5 months). The mean amount of sagittal surgical advancement was 6.7 +/- 2.3 mm, and the mean amount of postsurgical relapse was 1.3 +/- 2.0 mm, representing a 14% relapse of the original surgical advancement. However, individual variation in the amount and direction of movement of the mandible was found during the follow-up period. Postsurgical relapse was found to be related to the amount of surgical advancement. Linear-regression analysis between these two variables resulted in an R2 value of 0.448. Fourteen of the subjects relapsed in the posterior direction, with 2 relapsing more than 50% of the surgical advancement. Five of the subjects moved further anteriorly, with 1 advancing as much as 50% more than the original advancement. The findings of this study suggest that mandibular advancement with the sagittal ramus osteotomy and rigid fixation does not provide consistently stable postsurgical results. However, when compared with previously reported relapse studies using nonrigid fixation techniques, rigid fixation yielded superior results.     

Rapid maxillary distraction protocol utilizing the halo distraction system and rigid internal fixation.

OBJECTIVE: To shorten head frame wear time associated with external halo distraction (HD), we have adapted a protocol for maxillary distraction with the halo system that integrates plate fixation. PARTICIPANTS: All patients had a history of cleft lip and/or palate and maxillary retrusion > or = 8 mm. Five patients treated with this protocol and followed for at least 1 year were included in this study. INTERVENTIONS: The protocol included a 3-day latency period, variable maxillary distraction, and removal of the halo device with simultaneous rigid internal fixation. Two patients had a variable period of maxillomandibular fixation (MMF), which maintained the maxillary advancement and idealized intercuspal position while permitting further callus maturation. Cephalographs were obtained preoperatively, immediately following distractor removal, and 1 year after rigid internal fixation. RESULTS: The mean age at time of surgery was 18.7 years. The maxillary deficiency ranged from 8 to 15 mm (mean = 10.6 mm). All five patients demonstrated excellent occlusion. Cephalometric analysis 1-year post rigid internal fixation revealed minimal (<1 mm) skeletal relapse. CONCLUSIONS: Rapid maxillary distraction followed by MMF to maintain maxillary advancement may reduce halo device wear to 1 to 2 weeks. MMF optimizes occlusion by forcing the maxillary teeth into maximal intercuspal position. Rigid fixation is not only associated with less long-term relapse compared to nonrigid forms of fixation, but also minimizes the incidence of nonunion. This treatment protocol provides the advancement possible with distraction osteogenesis and the accuracy of orthognathic surgery, thereby minimizing external head frame wear.     

双侧下颌升支矢状劈开后退术后骨稳定性评价

目的 探讨影响双侧下颌升支矢状劈开后退术并行坚固内固定后骨稳定性的因素。方法 对进行双侧矢状劈开后退术后的15例患者于术后1周及术后1年摄头影测量侧位片,对其相关角度及线距进行测量,并作统计学处理。结果 下颌矢状劈开后退术1年后的平均复发量为2.5mm,后退量>6mm组与后退量<6mm组两者变化量之间无显著性差异。结论 下颌双侧矢状劈开后退术并行坚固内固定是矫正下颌前突最有效的方法之一。     

Recovery of mandibular mobility following orthognathic surgery

The aim of this prospective study was to define the patterns of recovery of mandibular mobility following three commonly performed orthognathic surgical procedures. Twenty-two consecutive patients undergoing either isolated Le Fort I osteotomy (LE FORT; n = 7), sagittal split ramus osteotomies (SSRO; n = 7), or intraoral vertical ramus osteotomies (IVRO; n = 9) were studied. LE FORT and SSRO patients had no mandibular immobilization, whereas IVRO patients were immobilized by dental fixation for 3 weeks. Mandibular mobility was assessed by measurement of maximal mandibular opening (MMO) and lateral and protrusive excursions. No significant difference in MMO was observed between groups prior to surgery (LE FORT, 47.0 mm; SSRO, 50.7 mm; IVRO, 54.5 mm). A significant reduction in MMO occurred immediately after surgery in the LE FORT and SSRO groups and at release of fixation in the IVRO group. Each group returned to presurgical levels of mandibular mobility at a different rate following surgery. LE FORT patients recovered quickly, regaining 83% (mean, 38.7 mm) of MMO by 1 month and exceeded preoperative levels (mean, 49.6 mm) by 6 months. SSRO patients showed hypomobility (mean, 23.5 mm) after 1 month, with significant improvement in MMO (mean, 38.0 mm) at 2 months, and nearly complete recovery (96.2%; mean, 48.8 mm) at 6 months. IVRO patients recovered rapidly after release of dental fixation, achieving 78% (mean, 39.8 mm) of preoperative MMO at 2 months. This study shows that significant differences in recovery patterns of mandibular mobility exist between surgical procedures. The clinician should be aware of these differences in recovery patterns in defining goals for individual patient rehabilitation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Short- and long-term skeletal relapse after mandibular advancement surgery

This study analyzes short- and long-term skeletal relapse after mandibular advancement surgery and determines its contributing factors. Thirty-two consecutive patients were treated for skeletal Class II malocclusion during the period between 1986 and 1989. They all had combined orthodontic and surgical treatment with BSSO and rigid fixation excluding other surgery. Of these, 15 patients (47%) were available for a long-term cephalography in 2000. The measurement was performed based on the serial cephalograms taken preoperatively; 1 week, 6 months and 14 months postoperatively; and at the final evaluation after an average of 12 years. Mean mandibular advancement was 4.1 mm at B-point and 4.9 mm at pogonion. Representing surgical mandibular ramus displacement, gonion moved downwards 2 mm immediately after surgery. During the short-term postoperative period, mandibular corpus length decreased only 0.5 mm, indicating that there was no osteotomy slippage. After the first year of observation, skeletal relapse was 1.3 mm at B-point and pogonion. The relapse continued, reaching a total of 2.3 mm after 12 years, corresponding to 50% of the mandibular advancement. Mandibular ramus length continuously decreased 1 mm during the same observation period, indicating progressive condylar resorption. No significant relationship between the amount of initial surgical advancement and skeletal relapse was found. Preoperative high mandibulo-nasal plane (ML-NL) angle appears to be associated with long-term skeletal relapse.     

Bilateral sagittal split osteotomy and temporomandibular disorders: rigid fixation versus wire fixation

OBJECTIVE: The effects of orthognathic surgery on temporomandibular disorders may be related to the surgical method that is used. Specifically, it has been suggested that the choice of stabilization technique may play a major role in the functional outcome of mandibular advancement surgery. The purpose of this study was to prospectively compare long-term (2 years) signs and symptoms of temporomandibular disorders after orthognathic surgery with bilateral sagittal split osteotomy in 127 patients randomized to receive rigid or wire fixation. STUDY DESIGN: Signs and symptoms of temporomandibular disorders were evaluated before and 2 years after surgery by means of the overall craniomandibular index (CMI), dysfunction index (DI), and muscle index (MI). Patients also reported subjective symptoms of temporomandibular disorders by marking areas of pain on a standard drawing of the head and rating the pain in each area on a scale ranging from 1 (very mild) to 7 (very extreme). Subjective pain was also assessed through use of the Oral Health Status Questionnaire and by a rating of the difficulty in opening the mouth because of pain. RESULTS: There were no statistically significant differences in the CMI, MI, or DI change scores between the wire and rigid fixation groups (mean CMI(wire) = 0.05, mean CMI(rigid) = 0.04; mean DI(wire) = 0.02, mean DI(rigid) = 0. 01; mean MI(wire) = 0.08, mean MI(rigid) = 0.08) 2 years after surgery. Temporomandibular joint sounds also demonstrated no significant differences between the two fixation methods. Subjective pain reports were consistent with the clinical examinations. On average, both wire and rigid scores decreased slightly, but the change scores were not significantly different between groups. CONCLUSIONS: These findings suggest that the long-term (2 years) effects of wire and rigid internal fixation methods on the signs and symptoms of temporomandibular disorders do not differ. Earlier concerns about increased risk for temporomandibular disorders with rigid fixation were not supported by these results.     

Superior repositioning of the maxilla combined with mandibular advancement: mandibular RIF improves stability.

Postsurgical changes in 24 patients who had rigid internal fixation (RIF) of the mandible with screws after combined superior repositioning of the maxilla and mandibular advancement were compared with 53 patients who underwent the same surgery but who had intraosseous wire fixation, skeletal suspension wires, and 8 weeks of maxillomandibular fixation (MMF). During the first 8 weeks after surgery, the mean posterior relapse of the mandible was greater in the MMF group than in the RIF group (for example, -1.1 mm versus 0.15 mm at B point), and the percentage of patients with clinically significant vertical and horizontal changes was greater in the MMF group. By 1 year, there had been slight additional mean relapse in the MMF group (-1.5 mm net relapse at B point, with 42% of the patients showing 2 mm or more relapse). In the RIF group, the mandible was more likely to be repositioned forward than posteriorly (net mean change at B point, 0.7 mm forward; 33% had 2 mm or more forward movement). In the RIF group, all but one of the patients (96%) were judged to have an excellent clinical result; in the MMF group, the corresponding figure was 60%.     

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.     

在正颌外科中用钢丝固定和坚硬内固定后并发症的比较研究

对１００例正颌外科病人应用钢丝固定或坚硬内固定的结果进行了回顾性比较，分析了两组病人所有并发症的发生情况．研究中最明显的发现是两种方法的结果基本相同，但在并发症中术后６个月体重过度减轻（≥５ｋｇ）和张口受限（中切牙最大张口度≤３５ｍｍ）两组间有明显差异，钢丝固定组分别为３０％和２４％，明显高于坚硬内固定组的８％和４％，主要是由于应用坚硬内固定的病人可以术后早期进行下颌运动，有利于饮食和咀嚼肌、颞颌关节的功能锻炼，而使术后体重过度减轻和张口受限的比例明显减少．由于坚硬内固定并没有增加正颌外科并发症的发生，而显示许多优点，因此将被广泛接受和应用