Condylar and disc positions after intraoral vertical ramus osteotomy with and without a Le Fort I osteotomy

Improvement of the temporomandibular joint symptoms due to the condylar position change following modified L-shaped intraoral vertico-sagittal ramus osteotomy: a single-center, retrospective study

PURPOSE

Intraoral vertico-sagittal ramus osteotomy (IVSRO) was first reported by Choung in 1992 as a surgical procedure to decrease postoperative condylar dislocation. In 2017, Iwanaga et al. developed modified L-shaped IVSRO (mIVSRO) to reduce postoperative nerve dysfunction and achieved favorable outcomes. This study aimed to clarify the effect of mIVSRO on changes in temporomandibular joint (TMJ) symptoms and three-dimensional condylar position.

METHODS

We conducted a retrospective study of thirty sides in fifteen Japanese adults diagnosed with jaw deformities who underwent mIVSRO and sagittal split ramus osteotomy (SSRO). TMJ symptoms were assessed chronologically, and the condylar long axis and the condylar position were analyzed two- and three-dimensionally using axial cephalograms and cone-beam computed tomography.

RESULTS

Postoperative TMJ symptoms improved by 90% (9/10 sides) in the mIVSRO group and by 50% (7/14 sides) in the SSRO group. The mIVSRO group exhibited outward rotation of the condylar long axis, while the SSRO group exhibited inward rotation. Moreover, mIVSRO induced residual anteromedial-inferior deviation of the condyle. The inclination angle of the condylar process was not significantly different between the two procedures pre- and postoperatively.

CONCLUSION

These results clearly demonstrated the effect of mIVSRO on symptomatic TMJ. Residual changes in the position of the condyle following mIVSRO may not affect jaw function.

Effect of Orthognathic Surgery on Pre-existing Temporomandibular Disorders

The management of patients with pre-existing temporomandibular disorders (TMDs) undergoing orthognathic surgery remains a subject of ongoing debate. This study aimed to profile these individuals and evaluate the correlation between orthognathic surgery and alterations in TMD indicators and symptoms. We conducted a retrospective cohort investigation involving patients with skeletal malocclusion and established TMDs. Variables of interest encompassed the performance of orthognathic surgery, documented TMDs (including temporomandibular joint (TMJ) sounds, TMJ pain, muscle discomfort, and jaw locking), and patients' self-assessments of TMJ and muscle pain using a visual analog scale (VAS). The primary outcome measures focused on changes in TMD indicators and symptoms. Among the study cohort, 73.4% exhibited skeletal class III malocclusion, while 26.6% presented with skeletal class II malocclusion. Notably, patients classified as skeletal class III were significantly younger than their skeletal class II counterparts (mean age: 23.06±5.37 vs. 26.71±7.33; P=0.034). The most prevalent pre-existing TMD complaint was TMJ sounds (65.5%), followed by TMJ pain (39.1%), muscle discomfort (23.4%), and jaw locking (12.5%). Skeletal class II patients were more likely to experience TMJ sounds compared to skeletal class III patients (88.2% vs. 57.4%; P=0.022). Statistically significant improvements were observed in the VAS assessments among class III patients following surgery. A majority of patients with pre-existing TMDs seeking orthognathic surgery exhibited skeletal class III malocclusion and were younger than those with skeletal class II malocclusion. Importantly, orthognathic surgery was associated with positive changes in TMD indicators and symptoms in these patients.

Volumetric changes in temporomandibular joint space following trans-oral vertical ramus osteotomy in patients with mandibular prognathism: a one-year follow-up study

This study measured and analyzed chronological changes in temporomandibular joint space volume by compartment following transoral vertical ramus osteotomy (TOVRO) using reconstructed 3-dimensional (3D) images of patients with mandibular prognathism. It included 70 joints of 35 patients who underwent TOVRO between January 2018 and December 2021. Computed tomography (CT) or cone-beam CT (CBCT) was performed before surgery (T0) and at 3 days (T1), 6 months (T2), and 12 months postoperatively (T3). These scans were then analyzed using 3D software. The volumes of the overall (Vjs), anterior (Vajs), posterior (Vpjs), medial (Vmjs), and lateral (Vljs) joint spaces were calculated at each time point. A linear mixed model and repeated-measures covariance pattern with unstructured covariance were used to evaluate significant changes in joint space volume over time. Vjs significantly increased to 134.54 ± 34.28 mm3 at T3 compared to T0 (p < 0.001). Vpjas and Vljs increased by 130.72 ± 10.07 mm3 and 109.98 ± 7.52 mm3 at T3 compared to T0, respectively (p < 0.001). However, no significant difference was observed between T0 and T2 in Vajs and Vmjs (p = 0.9999). The observed volume increases in Vpjs and Vljs appeared to contribute to the overall Vjs increase.

Biomechanical comparison of the effect of bilateral sagittal split ramus osteotomy with or without Le Fort I osteotomy on the temporomandibular joints of the patients with maxillofacial deformities under centric occlusion

Mandibular deformities negatively affect the daily activities of the patients and may cause temporomandibular disorders (TMD). Bilateral sagittal split ramus osteotomy (BSSRO) and Le Fort I osteotomy are effective treatments to correct the mandibular deformities. The aim of this study was to investigate and compare the effects of the BSSRO with or without Le Fort I on the stress distributions of the temporomandibular joints (TMJs) of the patients with mandibular deformities under centric occlusion based on finite element (FE) method. Preoperative and postoperative cone-beam computed tomography (CBCT) images of twenty-four patients diagnosed with mandibular prognathism, including ten patients with BSSRO and another 14 patients with bimaxillary osteotomy (BSSRO with Le Fort I), were used to construct maxillofacial models. Ten asymptomatic individuals were also performed CBCT scanning and defined as the control group. In addition, the muscle forces and boundary conditions corresponding to centric occlusions were applied on each model. For the preoperative groups with both the BSSRO and bimaxillary osteotomies, the average peak contact stresses of the TMJs were both greater than those of the control group. After the surgeries, the contact stresses of the discs and temporal bones of both groups considerably decreased. However, the contact stresses on the condyles slightly increased after BSSRO but decreased after bimaxillary osteotomy. The TMJs of the patients with maxillofacial deformities suffered abnormal tensile and compressive stresses compared with the asymptomatic subjects under centric occlusion. Both of the BSSRO and bimaxillary osteotomy could improve the risk stress distributions of the TMJs.

The three-dimensional evaluation of positional change in mandibular condyle after intraoral vertical ramus osteotomy

OBJECTIVES

The purpose of this study was to compare the changes of the condylar axis, the anteroposterior condylar position relative to the glenoid fossa, after intraoral vertical ramus osteotomy (IVRO).

STUDY DESIGN

21 patients diagnosed as skeletal class III malocclusion underwent IVRO and were followed according to the authors' postoperative management regimen. The three-dimensional positions of the condyles were evaluated by cone-beam computerized tomography (CBCT) at pre-op, post-op, and at follow-up. CBCT images were referenced to assess the condylar axis change and the anteroposterior condylar position in the glenoid fossa. A repeated-measures analysis of variance (P<0.05) also was performed.

RESULTS

After surgery, both the axial condylar angles and the anteroposterior condylar position were significantly different (P<0.05). The coronal condylar axis rotated outwardly. The anteroposterior condylar position in the glenoid fossa had moved from the concentric to the anterior position. But the condyle changes between post-op and follow-up (P>0.05) were insignificant.

CONCLUSIONS

With postoperative intermaxillary elastic traction, the condyles changed their positions physiologically for newly established jaw movement after IVRO.

A new approach in three dimensions to define pre- and intraoperative condyle-fossa relationships in orthognathic surgery - is there an effect of general anaesthesia on condylar position?

Incorrect registration of the condylar position in orthognathic surgery is supposed to cause postoperative relapse, condylar resorption and temporomandibular disorders. The aim of this prospective study was to evaluate the influence of general anaesthesia on centric relation (CR). Therefore, CR registered preoperatively in the awake patient and CR registered intraoperatively under general anaesthesia were recorded in 30 patients (14 men, 16 women) undergoing orthognathic surgery (skeletal class I: n=3, II: n=13, III: n=14; symmetric: n=20; asymmetric: n=10). CR records were digitized and, through superimposition on the preoperative cone beam computed tomography of the patient's skull, the superior, anterior and posterior joint space and the volumetric congruence of 120 condyles were analysed. The linear measurements of joint spaces did not demonstrate any clinically relevant discrepancy between the CR measured in the awake and anaesthetized patient. In contrast, volumetric analysis revealed statistically significant differences between both states, with an intraoperative condylar sag predominantly in the posterior-inferior direction. The patient's skeletal class or symmetry had no significant influence on the intraoperative condylar displacement. Thus, the risk of fixing the condyle in an unphysiological position supports the idea of using intraoperative condylar positioning devices to achieve predictable and stable outcomes.

Is There a Difference in Condyle Position Changing Pattern Between Deviated and Non-Deviated Sides After Intraoral Vertical Ramus Osteotomy in Facial Asymmetry?

PURPOSE

The position changing pattern of the condyles after intraoral vertical ramus osteotomy (IVRO) on the deviated and non-deviated sides is not clearly known. This study was conducted to evaluate the changes in condylar position after IVRO in patients with facial asymmetry and to compare the deviated and non-deviated sides using computed tomography imaging.

MATERIALS AND METHODS

This retrospective cohort study investigated patients with a diagnosis of mandibular prognathism with facial asymmetry who had undergone bilateral IVRO with Le Fort I osteotomy. Condylar positions were recorded on the non-deviated and deviated sides in the midaxial, midsagittal, and coronal planes at 3 time points using 3-dimensional analysis software: preoperatively (T1), at 6 months postoperatively (T2), and at 12 months postoperatively (T3). Linear and angular changes in condyle position were measured and analyzed between T1, T2, and T3. Reliability and comparative analyses were conducted.

RESULTS

Thirty-two patients were involved in this study. At T2, the most superior point of the condyle moved to 1.15 ± 0.24 mm (inferiorly) and 0.88 ± 0.23 mm (anteriorly) on the deviated side (P = .0002 and P = .0005, respectively) and to 0.99 ± 0.25 mm (inferiorly) and 1.08 ± 0.34 mm (anteriorly) on the non-deviated side, showing significant differences (P < .0001 and P = .0007, respectively) compared with T1. The condyle position showed a tendency to recover to its original position by T3. However, there were no statistically significant differences between T2 and T3 (P > .05). Furthermore, there were no statistically significant differences between the deviated and non-deviated sides over the entire follow-up period (P > .05).

CONCLUSIONS

The condyles did not completely recover to their preoperative positions until 12 months postoperatively. There was no significant difference between the deviated and non-deviated sides in mandibular prognathism with facial asymmetry.

Effects of the changes in the condylar long axis angle and condylar position on temporomandibular symptoms after intraoral vertical ramus osteotomy: a preliminary study

OBJECTIVE

This study was conducted to characterize the effects of the changes in the condylar long axis and position on temporomandibular symptoms with respect proximal segment position after intraoral vertical ramus osteotomy (IVRO).

STUDY DESIGN

Twenty Japanese patients with diagnosed jaw deformity underwent IVRO without internal fixation. Long-term changes in condylar long axis and position were assessed during postoperative follow-up examinations by using computed tomography, and t tests were performed for comparison. In addition, changes in temporomandibular symptoms were examined.

RESULTS

The degree of axial rotation of the proximal segment changed significantly when the proximal segment was located laterally. Downward changes in condylar position significantly differed when the proximal segment was located posterolaterally. Forward changes in condylar position significantly differed when the proximal segment was located laterally; moreover, when the proximal segment was located laterally, temporomandibular symptoms disappeared.

CONCLUSIONS

Lateral location of the proximal segment may be an important factor in the positive effects of IVRO, with respect to temporomandibular symptoms.

Safety and Stability of Postponed Maxillomandibular Fixation After Intraoral Vertical Ramus Osteotomy

The purpose of this study was to evaluate the postoperative safety and long-term stability of bimaxillary orthognathic patients with postponed maxillomandibular fixation (MMF) after intraoral vertical ramus osteotomy.A total of 61 patients (21 male and 40 female patients; average age [SD], 21.7 [4.7]) were enrolled. All patients underwent maxillary LeFort I osteotomy and bilateral intraoral vertical ramus osteotomy for mandibular prognathism. During the hospital stay, postoperative airway compromise was observed and patients underwent MMF with wire at the second postoperative day. Stability was evaluated by measuring the position at each period: preoperative (T0), 2-day postoperative (T1), and 1-year postoperative.Postoperative dyspnea and respiratory distress were absent in all patients. The mean number of refixations in physiotherapy was 0.62 (0.86) and the mean duration of physiotherapy was 11.6 (5.5) days. The mean amount of mandibular setback was 12.56 (5.76) mm and menton movement 0.98 (2.36) mm superiorly (T1). The mean mandibular relapse at Pog was 0.87 (1.96) mm anteriorly. Menton showed 1.11 (1.41) mm superiorly movement 1-year postoperatively (T2).Despite its many advantages, intraoral vertical ramus osteotomy requires a period of MMF which can lead to early discomfort and airway-related emergency. In this study, the physiotherapy procedure and postoperative long-term stability in the postponed MMF group were not different from those of an immediate MMF group studied previously. It therefore constitutes a viable option for oral breathers and other compromised patients.

Three-dimensional changes of proximal segments in facial asymmetry patients after bilateral vertical ramus osteotomy

The intraoral vertical ramus osteotomy (IVRO) is a useful technique for mandibular setback surgery. However, there is a tendency for lateral flaring of the proximal segments on the non-deviation side after the correction of mandibular asymmetry with this technique. The purpose of this retrospective study was to evaluate the positional changes of the proximal segments after IVRO setback in skeletal class III patients with asymmetry, using preoperative and postoperative computed tomography scan data, and to apply the results in clinical practice. A total of 28 skeletal class III patients with asymmetry who underwent bimaxillary orthognathic surgery were included. A three-dimensional cone beam computed tomography scan was obtained preoperative, at 1month postoperative, and at 1year postoperative. At 1month after the surgery, the proximal segments showed an outward rotation, lateral flaring, and anterior rotation of the condylar head. All postsurgical directional changes had returned to the preoperative state at 1year postoperative, and there was no statistically significant difference in postoperative angulation changes between the two sides. The results showed no statistical differences in the positional changes of the proximal segments between the deviation and non-deviation sides. This study reaffirms the benefits of the IVRO for a minimal bony interference between the proximal and distal segments in three dimensions, including mandibular asymmetry cases.

Changes in condylar position after BSSRO with and without Le Fort I osteotomy via surgery-first approach in mandibular prognathism with facial asymmetry

OBJECTIVES

This study aimed to evaluate changes in condylar position after bilateral sagittal split ramus osteotomy (BSSRO) with and without Le Fort I osteotomy via the surgery-first approach (SFA) in patients with facial asymmetry.

STUDY DESIGN

Eighteen patients (36 condyles) who received surgical-orthodontic treatment using the SFA were included and divided into 2 groups depending on the extent of surgery: BSSRO-only group (n = 12) and BSSRO with Le Fort I osteotomy group (n = 6). Using computed tomography images taken preoperatively, immediately postoperatively, and 6 months postoperatively, surgical and postoperative changes of the condylar position were analyzed 3-dimensionally.

RESULTS

Both groups showed mainly inferolateral displacement with inward rotation immediately after surgery, and superomedial returning movement with outward rotation 6 months after surgery. There was no statistical difference in time-course changes of the condylar position between the 2 groups. In comparing the deviated and nondeviated sides, the deviated side showed significantly greater amount of bodily shift and rotational movement after surgery compared with the nondeviated side in both groups.

CONCLUSIONS

These results suggest that BSSRO via the SFA, either with or without Le Fort I osteotomy, may cause condylar displacement after surgery and that the displaced condyles return to their original position on both the deviated and the nondeviated sides.

The effect of orthognathic surgery on the temporomandibular joint and oral function: a systematic review

The objective of this systematic review was to examine the effect of orthognathic surgery (OS) on the temporomandibular joint and oral function. Electronic databases were systematically searched for studies published until October 2015. Articles were assessed against predefined inclusion criteria. The included papers were divided into four groups based on the type of OS performed. The following items were recorded: quality of evidence using the Oxford Centre for Evidence-Based medicine (CEBM) criteria, number of patients, presence/absence of controls, mean age at treatment, follow-up time, clinical examination findings, bite force, use of the Helkimo Index and Research Diagnostic Criteria for Temporomandibular Disorders, imaging findings, and patient questionnaire results. A total of 4669 articles were identified; 76 relevant articles were included in the review. These studies assessed a total 3399 patients and 380 controls, with a mean age of 25.4 years. The great variety of OS techniques, examination techniques, diagnostic criteria, and imaging techniques used in the articles studied, as well as the quality of the study designs, made it difficult to compare studies and to draw conclusions. However, looking at the different aspects studied in general, it can be stated that OS seems to have little or no harmful effect on the TMJ and oral function (level of evidence: levels II, III, and IV).

Complications associated with orthognathic surgery

While most patients undergo orthognathic surgery for aesthetic purposes, aesthetic improvements are most often followed by postoperative functional complications. Therefore, patients must carefully decide whether their purpose of undergoing orthognathic surgery lies on the aesthetic side or the functional side. There is a wide variety of complications associated with orthognathic surgery. There should be a clear distinction between malpractice and complications. Complications can be resolved without any serious problems if the cause is detected early and adequate treatment provided. Oral and maxillofacial surgeons must have a full understanding of the types, causes, and treatment of complications, and should deliver this information to patients who develop these complications.

Orthognathic surgery and temporomandibular joint symptoms

The aim of this article is to review temporomandibular joint symptoms as well as the effects of orthognathic surgery(OGS) on temporomandibular joint(TMJ). The causes of temporomandibular joint disease(TMD) are multifactorial, and the symptoms of TMD manifest as a limited range of motion of mandible, pain in masticatory muscles and TMJ, Joint noise (clicking, popping, or crepitus), myofascial pain, and other functional limitations. Treatment must be started based on the proper diagnosis, and almost symptoms could be subsided by reversible options. Minimally invasive options and open arthroplasty are also available following reversible treatment when indicated.

TMD manifesting in a variety of symptoms, also can apply abnormal stress to mandibular condyles and affect its growth pattern of mandible. Thus, adaptive developmental changes on mandibular condyles and post-developmental degenerative changes of mandibular condyles can create alteration on facial skeleton and occlusion. The changes of facial skeleton in DFD patients following OGS have an impact on TMJ, masticatory musculature, and surrounding soft tissues, and the changes of TMJ symptoms. Maxillofacial surgeons must remind that any surgical procedures involving mandibular osteotomy can directly affect TMJ symptoms, thus pre-existing TMJ symptoms and diagnoses should be considered prior to treatment planning and OGS.

Unilateral mandibular advancement with bilateral intraoral vertical ramus osteotomy

Intraoral vertical ramus osteotomy (IVRO) is an effective surgical procedure that is used for the correction of mandibular prognathism. However, application of IVRO for mandibular advancement has been limited because of the instability of the proximal segments caused by the gap between the distal and proximal segments. We report a case of unilateral mandibular advancement with bilateral IVRO for the correction of facial asymmetry. This case shows possible application of bilateral IVRO for unilateral mandibular advancement without any means of fixation.

Unilateral intraoral vertical ramus osteotomy and sagittal split ramus osteotomy for the treatment of asymmetric mandibles

In surgery for facial asymmetry, mandibles can be classified into two types, rotational and translational, according to the required mandibular movements for surgery. During surgery for rotational mandibular asymmetry, a bilateral sagittal split ramus osteotomy (BSSRO) may cause a large bone gap between the proximal and distal segments as well as condylar displacement, resulting in a relapse of the temporomandibular joint disorder, especially in severe cases. The intraoral vertical ramus osteotomy has an advantage, in this respect, because it causes less rotational displacement of the proximal segment on the deviated side and even displaced or rotated condylar segments may return to their original physiologic position. Unilateral intraoral vertical ramus osteotomy (UIVRO) on the short side combined with contralateral SSRO was devised as an alternative technique to resolve the spatial problems caused by conventional SSRO in cases of severe rotational asymmetry. A series of three cases were treated with the previously suggested protocol and the follow-up period was analyzed. In serial cases, UIVRO combined with contralateral SSRO may avoid mediolateral flaring of the bone segments and condylar dislocation, and result in improved condition of the temporomandibular joint. UIVRO combined with contralateral SSRO is expected to be a useful technique for the treatment of rotational mandibular asymmetry.

Avoiding condylar displacement after intraoral vertical ramus osteotomy

The intraoral vertical osteotomy is a versatile and simple technique usually applied to correct mandibular prognathism. Its greatest advantages include ease of performance and minimum neurosensory disturbances, whereas maxillomandibular fixation is pointed as its major disadvantage. Another important concern about this technique is condylar displacement, which may lead to temporomandibular dysfunction. Technical notes to avoid condylar luxation are discussed after 15 years of experience using this osteotomy as the technique of choice to correct mandibular prognathism. Three similar cases are presented, where 1 condyle was displaced from the glenoid fossa, resulting in mandibular deviation during function in patients requiring small mandibular setback.

Oral and maxillofacial surgery and chronic painful temporomandibular disorders--a systematic review

PURPOSE

To provide a systematic review of the best available research literature investigating the relation of oral and maxillofacial surgical procedures to the onset or relief of chronic painful temporomandibular disorder (TMD).

MATERIALS AND METHODS

A comprehensive review of the databases CINAHL, Cochrane Library, Embase, Medline, NHS Evidence--Oral Health, PsycINFO, Web of Knowledge, and MetaLib was undertaken by 2 authors (P.S., M.H.) up to June 2009 using search terms appropriate to establishing a relation between orofacial surgical procedures and TMD. The search was restricted to English-language publications.

RESULTS

Of the 1,777 titles reviewed, 35 articles were critically appraised but only 32 articles were considered eligible. These were observational studies that fell into 2 groups; 9 were seeking to establish a surgical cause for TMD. Of these, only 2 of a series of 3 claimed that there was a significant link, but this claim was based on weak data (health insurance records) and was abandoned in a subsequent report. Twenty-three studies were seeking to achieve relief by orthognathic surgical intervention. These were also negative overall, with 7 articles showing varying degrees of mostly nonsignificant improvement, whereas 16 showed no change or a worse outcome. No published report on the putative effect of implant insertion was found.

CONCLUSION

These apparently contradictory approaches underline a belief that oral surgical trauma or gross malocclusion has a causative role in the onset of TMD. However, there was no overall evidence of a surgical causal etiology or orthognathic therapeutic value. This review emphasizes that it is in the patients' best interest to carry out prospective appropriately controlled randomized trials to clarify the situation.

The effects of changing position and angle of the proximal segment after intraoral vertical ramus osteotomy

The authors evaluated changes in position and angle of the proximal segment, including the condyle, after intraoral vertical ramus osteotomy (IVRO) with and without a Le Fort I osteotomy to verify whether displacement of the proximal segment could induce postoperative complications. Changes in condylar angle, ramus angle, and displacement of proximal segment were measured pre- and postoperatively. The position of the temporomandibular joint (TMJ) disc was examined pre- and postoperatively. Trigeminal nerve hypoesthesia in the lower lip was assessed bilaterally. The postoperative horizontal condylar angle was significantly smaller than the preoperative one on the deviated and non-deviated sides (P<0.0001). The postoperative coronal condylar angle was significantly larger than the preoperative one on the deviated side (P=0.0483). The postoperative sagittal ramus angle was larger than the preoperative one on the deviated (P<0.0001) and non-deviated (P=0.00005) side. Most joints with an anteriorly-displaced disc with and without reduction improved on the non-deviated side; 5 of 16 joints improved on the deviated side. Results suggest the position and angle of the proximal segment, including the condyle, could change after IVRO. This could be associated with symptomatic improvement in TMJ, and extreme medial displacement of the proximal segment could delay recovery from lower lip hypoesthesia.