Risk factors related to aggressive condylar resorption after orthognathic surgery for females: retrospective study

Objective: The aim of the present study was to identify the risk factors for aggressive condylar resorption (ACR) after orthognathic surgery.

Methods: A total of 25 female patients with osteoarthritis (OA) scheduled for orthognathic surgery were divided into two groups: those who exhibited ACR (ACR (+), n = 8) and those who did not exhibit ACR (ACR (?), n = 17) after surgery. Clinical indices were used to determine the extent of mandibular advancement, the presence of temporomandibular disorder (TMD), and relevant medical treatment histories (including the use of oral contraceptive (OC) medication. TMJ dysfunction was clinically evaluated in terms of pain, the presence of sounds (clicks or crepitus), and disc displacement, joint effusion (JE), and synovial hyperplasia (SH); these were further investigated with the aid of magnetic resonance imaging (MRI). The cephalographic findings were compared with the normal profiles of Japanese subjects.

Results: The mean (with SD) extent of mandibular advancement was 11.4 mm (2.4) in ACR (+) and 4.1 mm (1.8) in ACR (?). The TMD medical history of ACR (+) was much more extensive than that of ACR (?); all patients in ACR (+) had a history of OC use. More patients in ACR (+) than in ACR (?) had TMJ dysfunction and disc displacement, JE, and SH on MRI. Preoperative cephalograms showed that ACR (+) patients exhibited counterclockwise rotation of the mandible and retrognathism that was attributable to a small sella–nasion–B (SNB) angle, a wide mandibular plane angle, and a negative inclination of the ramus.

Conclusions: The present findings suggest that the development of ACR after orthognathic surgery to treat mandibular retrognathism may be associated with coexisting TMJ pathologic abnormality.     

Relapse after SSRO for mandibular setback movement in relation to the amount of mandibular setback and intraoperative clockwise rotation of the proximal segment

The aim of this study was to evaluate the effect of the amount of setback movement and intraoperative clockwise rotation of the proximal segments on postoperative stability after orthognathic surgery to correct mandibular prognathism.Thirty-six patients with mandibular prognathism who underwent orthognathic surgery with bilateral sagittal split ramus osteotomy were evaluated. The amount of postoperative relapse was analyzed using a cephalometric analysis.Six months after surgery, the mean backward movement of the mandible at point B was 11.2 mm, the mean intraoperative clockwise rotation of the proximal segment was 4.3° and the amount of postoperative relapse at point B was 2.3 mm (20.3%) on average. The tendency of relapse did not significantly increase with the amount of setback but did increase significantly with the intraoperative clockwise rotation of the proximal segment.This study suggested that postoperative relapse after mandibular setback surgery might be more related to the degree of the intraoperative clockwise movement of the proximal segment, rather than the amount of setback movement. When the amount of mandibular setback is considerable, postoperative relapse might be minimized with adequate control of the intraoperative positioning of the proximal segments.     

Surgical risk factors for condylar resorption after orthognathic surgery

OBJECTIVE: The purpose of this study was to look for surgical risk factors for condylar resorption after orthognathic surgery.Study Design: Seventeen patients of a group of 452 patients who had undergone orthognathic surgery consecutively and who were in accordance with the inclusion criteria of this study showed postoperative condylar resorption (group I). Preoperative cephalometric characteristics and surgically induced movements of this group were compared with a control group of 17 of 452 patients (group II) in whom postoperative condylar resorption and skeletal relapse did not develop, despite mandibular retrognathism (ANB angle >4 degrees) and high mandibular plane angle (>40 degrees). RESULTS: The kind of osteosynthesis used was not significantly different between the 2 groups. The amount of surgical advancements and the vertical movements of the jaws were not significantly different between the 2 groups. However, the distal (P =.005) and proximal (P =.007) mandibular segments were rotated significantly further counterclockwise in group I. Surgically induced posterior condylar displacement occurred significantly more frequently (P =.007) in group I. CONCLUSIONS: Counterclockwise rotation of the distal and proximal mandibular segments and surgically induced posterior condylar displacement seem to be important surgical risk factors for postoperative condylar resorption. Therefore, these movements seem to be contraindicated in patients who are at high risk.     

Assessment of condylar changes after orthognathic surgery using computed tomography regional superimposition

This study aimed to investigate the effects of bimaxillary advancement orthognathic surgery on the condylar remodeling of the temporomandibular joint (TMJ) using voxel-based regional superimposition of cone-beam computed tomography (CBCT).In this retrospective study, the sample comprised 56 condyles from 28 healthy patients (aged from 16 to 50 years) with mandibular retrognathism treated with bimaxillary advancement. CBCT scans were taken preoperatively and at 14.3 ± 4.2 months postoperatively. The scans at the two time points were superimposed using regional voxel-based registration to assess condylar changes in the follow-up period. The linear alterations were measured in six different areas of each condyle to determine the pattern of condylar remodeling.Although no significant correlation was observed between changes in condylar surfaces, bone resorption occurred predominantly in the posterior and superior regions, while bone formation was predominantly on the anterior surface. Medial and lateral surfaces presented fewer bone changes. The overall bone changes were smaller than 1 mm bilaterally in 21 patients (75%) and, considering each condyle individually, were smaller than 1 mm in 48 condyles (85.7%).The results suggested that mild condylar remodeling in healthy patients is a common finding after orthognathic surgery. Future studies may clarify the mechanisms involved in the remodeling and help to understand the reasons for the remodeling pattern.     

功能板影响错伴特发性髁突吸收正颌术后稳定性的初步研究

目的:探讨特发性髁突吸收（idiopathic condylar resorption, ICR）患者在关节功能板治疗结合正颌-正畸联合治疗后下颌骨及髁突位置的改变,为后期研究提供依据。方法:回顾分析2008—2012年收治的13例特发性髁突吸收患者的临床数据,所有患者均在正颌手术前接受关节功能板治疗7.5±1.5个月。对患者正颌术前(T0)、正颌术后即刻(T1)、正颌术后至少12个月(T2)的咬合、头颅侧位片、MRI检查结果进行测量,采用SPSS 22.0软件包对数据进行统计学分析,评价正颌术后髁突和下颌骨的位置变化。结果:正颌手术(T1)纠正了所有患者的骨性Ⅱ类错畸形,建立了正常的咬合关系、前伸运动及侧方斜导运动。正颌手术平均下颌骨前移量(Y Axis-B, T1-T0)为（5.05±3.54）mm。与T1相比,T2时颞下颌关节间隙参数无显著改变。下颌骨位置参数中, 仅Y轴到B点的距离（Y轴-B）在T2与T1间存在统计学差异,其改变量平均值为（-1.64±2.48）mm,其余参数均无显著差异。13例患者中,11例患者Y轴-B 改变值<2 mm（84.6%）,仅 2例患者出现>2 mm的后退（15.4%）。结论:关节功能板治疗可增加ICR患者正颌手术的稳定性,可能是关节功能板保守治疗能够稳定ICR患者髁突在关节窝内的位置。     

Idiopathic condylar resorption: Diagnosis, treatment protocol, and outcomes

Idiopathic condylar resorption is a poorly understood progressive disease that affects the TMJ and that can result in malocclusion, facial disfigurement, TMJ dysfunction, and pain. This article presents the diagnostic criteria for idiopathic condylar resorption and a new treatment protocol for management of this pathologic condition. Idiopathic condylar resorption most often occurs in teenage girls but can occur at any age, although rarely over the age of 40 years. These patients have a common facial morphology including: (1) high occlusal and mandibular plane angles, (2) progressively retruding mandible, and (3) Class II occlusion with or without open bite. Imaging usually demonstrates small resorbing condyles and TMJ articular disk dislocations. A specific treatment protocol has been developed to treat this condition that includes: (1) removal of hyperplastic synovial and bilaminar tissue; (2) disk repositioning and ligament repair; and (3) indicated orthognathic surgery to correct the functional and esthetic facial deformity. Patients with this condition respond well to the treatment protocol presented herein with elimination of the disease process. Two cases are presented to demonstrate this treatment protocol and outcomes that can be achieved. Idiopathic condylar resorption is a progressive disease that can be eliminated with the appropriate treatment protocol.     

The influence of pre- and intraoperative positioning of the condyle in the centre of the articular fossa on the position of the disc in orthognathic surgery. A magnetic resonance study

OBJECTIVE: We investigated the changes in the temporomandibular joint (TMJ) after bilateral sagittal split osteotomy of the mandible for orthognathic surgery and the influence of positioning of the condylar process in the centre of the articular fossa before and during the operation for preventing changes in the TMJ postoperatively. STUDY DESIGN: A total of 28 patients with mandibular retrognathism had bilateral sagittal split osteotomies for mandibular advancement. In one group of 14 patients (28 TMJ), the condyles were placed in the centre of the articular fossa before and during the operation, and in the other group they were not. Differences on magnetic resonance imaging (MRI) were calculated and the results were evaluated. RESULTS: The main differences were found at maximal mouth opening. 15/28 TMJs (54%) that had not been positioned changed the position of the disc from physiological to anterior disc derangement with and without reduction postoperatively. In the 28 that had been positioned, changes were found in only 3 TMJs (11%) postoperatively. CONCLUSIONS: Fixing the condylar process in the centre of the articular fossa intraoperatively before bilateral sagittal split osteotomy is a factor in preventing postoperative structural changes in the temporomandibular joint.     

The role of a posteriorly inclined condylar neck in condylar resorption after orthognathic surgery.

Recently, it has been reported that a posteriorly inclined condylar neck is associated with condylar resorption following orthognathic surgery, although its role in resorption remains unknown. By cephalometric screening of 240 patients with Angle Class II occlusion 2 years after orthognathic surgery, 11 patients with postoperative condylar resorption were identified. The preoperative posterior inclination of the condylar neck and the surgical risk factors mentioned in the literature, particularly surgically induced counterclockwise rotation of the mandibular proximal segment were evaluated. In all 11 cases, the condylar neck was clearly inclined posteriorly. Counterclockwise rotation of the proximal segment was also observed in all cases, and it amounted to 6.7 degrees (2.5-12 degrees) on average. The contributing role of a posteriorly inclined condylar neck in connection with surgical mandibular movement in postoperative condylar resorption is discussed.     

Three-dimensional volumetric analysis of condylar head and glenoid cavity after mandibular advancement

The aim of this study was to assess condylar resorption, spatial change in glenoid cavity, and its risk factors after mandibular advancement by three-dimensional volumetric analysis. Subjects consisted of 30 condyles of 15 patients diagnosed with mandibular retrognathism who underwent Le Fort I and bilateral sagittal split ramus osteotomy advancement. CBCT images were taken before surgery (T0), immediately after surgery (T1), and postoperatively at 6 months (T2) and 1 year (T3). Condylar resorption was observed in 21 condyles. The posterior was the most affected region, while the anterior was the least affected. The volume of the glenoid cavity was significantly increased after surgery regardless of the presence or absence of resorption. However, the cavity recovered close to its original volume over time. At 1 year after surgery, the volume was not significantly different from the preoperative volume. Counterclockwise rotation of the proximal segment was found to be a risk factor affecting resorption based on correlation analysis. Mandibular advancement appeared to generate excessive mechanical stress on the posterior condyle, and might be responsible for the resorption. Counterclockwise rotation might have added stress to the region. Articular spatial change was transient and did not appear to be related to condyle resorption.     

The role of mandibular stabilization in orthognathic surgery

Stability of the temporomandibular joint (TMJ) structure is a critical requirement for treatment that includes orthognathic surgery. If the condyles are not positioned properly in the articular fossae during the manual positioning of the condyle or the intermaxillary fixation, postoperative relapse can result. However, it is difficult for the orthognathic surgeon to control the positioning of the mandibular condyles during orthognathic surgery due to muscle relaxation and the harsh intraoperative environment. Well-managed presurgical orthodontic treatment does not always guarantee the proper positioning of the proximal segment either, especially if the TMJ structures are not stable in their functional area. Therefore, the mandible should be stabilized with a presurgical stabilization splint to provide proper stimulation that forms a pseudodisc in the TMJ structures before surgical procedures.     

The quantitative correlation between condylar resorption and skeletal relapse following mandibular advancement in skeletal class II malocclusion patients

ObjectiveThe purpose of this study was to analyze the quantitative correlation between condylar resorption and skeletal relapse after mandibular advancement surgery.Materials and methodsSkeletal Class II malocclusion patients who underwent bilateral sagittal split ramus osteotomy (BSSRO) were included. Three-dimensional reconstruction was based on one-week and one-year post-operative CT scans. The condylar morphological alterations were assessed by anterior-posterior, medial-lateral diameter and condylar height. The mandibular relapse was calculated by the positional changes of pogonion, menton, gonions, gnathion and mental foramens. All data were measured by MIMICS and analyzed by SPSS software; significance was set at p<0.05.Results31 patients (62 condyles) were enrolled into this study. 28 of 62 condyles showed resorption beyond 1 mm on condylar height and 15 were beyond 2 mm. Positional changes of chin, mental foramens and gonion were respectively 1.57 ± 2.36 mm, 1.31 ± 1.23 mm and 1.42 ± 1.02 mm. 21 of 31 patients experienced mandibular relapse less than 1 mm but additional 4 patients showing relapse more than 2 mm. Correlation with moderate intensity could be observed between condylar height alteration and post-operative mandibular displacement more than 1 mm (p = 0.035).ConclusionThe resorption degree of condylar height can be regarded as a useful parameter for evaluating post-operative skeletal relapse.     

Mandibular advancement using a retrocondylar cartilage graft: a 20-year prospective study

We examined the outcome after a mean of 46 months (range 18-204) of 73 patients with severe mandibular retrusion who had surgical advancement of the mandible by a post-condylar cartilage graft. The extent of the mandibular advance and the change in position of the condyle were measured by a previously described cephalometric method. Tomograms of the temporomandibular joint (TMJ) were taken at defined intervals and any changes in the articulation recorded. The mandible was advanced by a mean (S.D.) of 9.8 (3.4) mm. The mean postoperative change recorded on the final cephalometric radiograph was 0.4 (4.7) mm forward (95% CI -0.70 to+1.50). The mandibular condyle was advanced horizontally by a mean 7.2 (2.1) mm and depressed vertically by a mean of 5.9 (2.6) mm. postoperatively the condyle relapsed horizontally by a mean of 1.5mm and moved vertically downward by a mean of 0.2mm. Eleven patients had substantial skeletal relapse. Eight patients were regarded as clinical failures. Skeletal relapse did not always lead to clinical failure because of compensatory mandibular growth. Changes in the condylar region, which contributed to relapse, included condylar absorption and remodelling (n=7) and absorption of the cartilage graft (n=6). There were no postoperative functional problems with the TMJ. We conclude that the post-condylar cartilage graft is a useful technique for the treatment of certain cases of mandibular retrusion. The postoperative morbidity was less than that reported after other techniques of mandibular advancement including distraction. Skeletal relapse was found in more cases than clinical results had suggested.     

Non-surgical risk factors for condylar resorption after orthognathic surgery.

BACKGROUND: Condylar resorption following orthognathic surgery is an important cause of late skeletal relapse. However, its pathogenesis is not well understood. The purpose of this study was to find non-surgical risk factors for condylar resorption after orthognathic surgery. PATIENTS: In this retrospective study, 17 patients (Group I) who developed postoperative condylar resorption were selected. These patients were compared with 22 patients (Group II) without postoperative condylar resorption, but who showed mandibular hypoplasia with a preoperative high mandibular plane angle of more than 40 degrees. METHODS: Possible non-surgical risk factors were sought by analysing clinical and radiological data collected preoperatively and immediately, 6 weeks, and 1 and 2 years postoperatively. RESULTS: There was no significant difference of gender distribution between the two groups. Patients in Group I were significantly younger (p=0.02) than those in Group II. The incidence of temporomandibular joint dysfunction in both groups was similar preoperatively, but was significantly higher (p=0.001) postoperatively in Group I. The posterior inclination of the condylar neck in Group I was also significantly greater (p<0.001). The preoperative mandibular plane angle in Group I (mean value: 49.4 degrees ) was significantly greater (p=0.005) than in Group II (mean value: 44.9 degrees ). The preoperative SNB angle, overbite, and posterior facial height and ratio (posterior/anterior facial heights) in Group I were significantly smaller (p<0.05). CONCLUSION: The present study suggests that the posteriorly inclined condylar neck should be considered as a relevant non-surgical risk factor.     

骨性Ⅱ类错伴颞下颌关节紊乱矫正后的长期稳定性

目的:研究骨性Ⅱ类错伴颞下颌关节紊乱患者在正颌-正畸联合治疗后面型和咬合的长期稳定性。方法:选择10例在本院正颌-正畸中心治疗结束3年以上、资料齐全的骨性Ⅱ类错患者,男2例,女8例,平均年龄(22.3±2.9)岁,治疗结束平均随访期(2.63±1.36)a。治疗方案为术前正畸、正颌手术、术后正畸,手术根据面型测量数据采用双颌手术或上颌手术+颏成形,术中采用坚强内固定。比较治疗前(T0)、治疗结束(T1)和随访结束(T2)的X线头影测量数据,评价颞下颌关节(TMJ)症状量表和MRI的变化。采用SPSS16.0软件包分别对治疗前、随访结束与治疗结束的测量数据进行配对t检验。结果:覆盖平均增加0.62mm,有显著性差异,其余骨性、牙性复发和软组织改建无统计学意义;随访结束UI-NA距离、覆盖和覆变化>2mm占10%,Go-Co长度变化>2mm占20%,软组织颏前点的变化量>2mm占40%,LI-NB距离和颏唇沟的深度变化均小于2mm;所有患者关节症状无加重,MRI未见髁突吸收加重,盘髁关系未见明显改变。结论:骨性Ⅱ类错伴TMD患者通过正颌-正畸联合治疗,能获得面型美观和正常的咬合关系,远期面型结构及咬合关系未见明显复发趋势,未发现TMJ症状加重趋势。     

Concomitant temporomandibular joint and orthognathic surgery: a preliminary report.

PURPOSE: In the present study, we evaluated the outcome of concomitant temporomandibular joint (TMJ) and orthognathic surgery in patients with TMJ articular disc dislocation and coexisting dentofacial deformities. PATIENTS AND METHODS: The records of 70 patients treated with TMJ articular disc-repositioning surgery and concomitant orthognathic surgery (double jaw or only mandibular surgery) were retrospectively evaluated. Patients were divided into the following 3 groups: group 1 patients had mandibular advancement, group 2 patients had mandibular setback, and group 3 patients had a mandible that remained in the original position. Lateral cephalometric radiographs and lateral cephalometric tomograms were assessed at the following intervals: before surgery (T1), immediately after surgery (T2), 6 to 12 months after surgery (T3), and at the longest follow-up (T4). Lateral cephalometric tracings were superimposed to calculate surgical change (T2 - T1), short-term stability (T3 - T2), and long-term stability (T4 - T3) of the orthognathic surgery procedures. Maximum interincisal opening (MIO) and subjective TMJ pain (visual analog scales) were comparatively evaluated at T1 and T4. RESULTS: Subjective TMJ pain levels and MIO improved in all 3 groups after surgery. Before surgery, 56 of 70 patients (80%) had pain and 14 of 70 patients (20%) had no pain. At the longest follow-up, 42 of 70 patients (60%) reported complete relief of TMJ pain. Only 5 of 70 patients (7%) had severe pain after surgery compared with 37 of 70 patients (53%) before surgery. At the longest follow-up, 6 of 70 patients (9%) showed less than 35 mm MIO, residual severe pain, or both. One patient had significant condylar resorption after surgery. The orthognathic procedures were found to be stable in the long term. Concomitant TMJ and orthognathic surgery had an overall success rate of 91.4% based on a greater than 35 mm MIO and a decrease in pain. CONCLUSIONS: When indicated, TMJ and orthognathic surgery can be concomitantly performed with predictable results and a good success rate. Strong consideration should be given to early surgical intervention because the success rate decreases significantly with pre-existing TMJ dysfunction of greater than 48 months' duration.     

Evaluation of condylar resorption rates after orthognathic surgery in class II and III dentofacial deformities: A systematic review

The purpose of this study was to perform a systematic review of morphological alterations in the condyles after orthographic surgery involving a sagittal split ramus osteotomy (SSRO), with or without surgery on the maxilla. Searches were performed on three databases and registered in the PROSPERO. The selected studies fulfilled the criteria established by the following PICO model: (1) population: individuals with skeletal dentofacial deformities (class II or III facial patterns), without asymmetry; (2) intervention: orthognathic surgery for mandibular setback using an SSRO, with or without a Le Fort I osteotomy, and fixed with bicortical screws or plates and screws; (3) comparison: orthognathic surgery for mandibular advancement using an SSRO, with or without a Le Fort I osteotomy, and fixed with plates and screws or bicortical screws; and (4) outcome: condylar resorption rate and relapse. Initially, 1,371 articles were identified and 636 articles were screened after elimination of duplicates, and 6 articles were selected for qualitative analysis based on the inclusion and exclusion criteria. Five studies had data regarding the rate of condylar resorption, varying from 0.0% to 4.2%. In conclusion, condylar resorption and relapses were present in a small percentage of patients studied.     

渐进性髁突吸收致下颌后缩正颌外科的治疗进展

病因及发病机制仍不明确的渐进性/特异性髁突吸收(PCR/ICR),是一种发生在髁突的罕见的骨吸收性疾病,临床表现为髁突形态改变、体积减小和下颌升支高度降低等,后期往往出现比较严重的下颌后缩畸形及咬合功能障碍.手术作为一种治疗牙颌面畸形的有效方案,可以达到功能性及面型美观的改善.本文就PCR致下颌后缩的正颌外科治疗作一综述.     

Study of condylar positional changes after sagittal split osteotomy for mandibular advancement: A prospective cohort study

Purpose

To analyse the possible morphologic and positional changes of the mandibular condyles after orthognathic surgery.

Three-dimensional condylar displacement and remodelling following correction of asymmetric mandibular prognathism with maxillary canting

The aim of this study was to investigate the three-dimensional condylar displacement and long-term remodelling following the correction of asymmetric mandibular prognathism with maxillary canting. Thirty consecutive patients (60 condyles) with asymmetric mandibular prognathism >4 mm and occlusal canting >3 mm, treated by Le Fort I osteotomy and bilateral sagittal split ramus osteotomy, were included. Spiral computed tomography scans obtained at different periods during long-term follow-up (mean 17 ± 7.2 months) were gathered and processed using ITK-SNAP and 3D Slicer. The condyles were subjected to translational and rotational displacements immediately after the surgery (T2), which had not fully returned to the original preoperative positions at the last follow-up (T3). Condylar remodelling was observed at the last follow-up (T3), with the shorter side condyles subjected to higher surface resorption and overall condylar volume loss. The overall condylar volume on the shorter side was significantly reduced compared to the volume on the elongated side (?11.9 ± 90.6 vs ?131.7 ± 138.2 mm³; P = 0.001). About 73%, 87%, 53%, and 54% of the shorter side condyles experienced resorption on the posterior, superior, medial, and lateral surfaces, respectively; in contrast, only 50% of the elongated side condyles showed resorption on the superior surface. Higher preoperative asymmetry was significantly correlated with increased postoperative condylar displacement (P < 0.05). The vertical asymmetry and the vector of condylar displacement were associated with the resultant remodelling process. It is concluded that condylar resorption of the shorter side condyle, which may affect the long-term surgical stability, has to be considered.     

Condylar position following mandibular advancement: Its relationship to relapse

Forty-one patients who elected to receive a bilateral sagittal osteotomy to advance the mandible were examined clinically and radiographically to assess condylar position preoperatively and at three specific times post-operatively. Parameters designed to measure changes in condylar and distal fragment position were located on tracings and digitized for statistical analysis. Changes in distal fragment position included advancement and clockwise rotation during the surgical interval and significant posterior relapse with continued clockwide rotation during the period of maxillomandibular fixation. A small amount of counterclockwise rotation associated with interocclusal splint removal was seen following fixation release. No significant condylar movement was seen during the surgical interval. During the period of maxillomandibular fixation, both condyles exhibited a significant superior movement, and the left condyle also moved posteriorly. No changes in condylar position were noted following release of fixation. The clinical significance of these condylar movements is not clear. Despite minimal changes, 18 patients, six of whom had had no preoperative symptoms and one of whom had exhibited reciprocal clicking, complained of temporomandibular joint pain or noise postoperatively. This suggests that maintenance of condylar position during surgery may not prevent temporomandibular joint dysfunction. In addition, the observed 37% relapse in surgical advancement in the absence of significant condylar distraction implies the interaction of other factors in the relapse process.