Condylar position and mandibular function after bilateral sagittal split osteotomy.

AIM: The purpose of this retrospective study was to perform an evaluation of postoperative positional changes of the condyle and mandibular function after bilateral sagittal split osteotomy (BSSO) with manual proximal segment positioning. PATIENTS: 45 patients were divided into the 2 groups ‒ G1 (advancement ‒ 14 patients) and G2 (setback - 31 patients). Rigid internal fixation screws were utilized in all cases. Inclusion criteria were only BSSO, no TMJ symptoms preoperatively and age 18 or older. RESULTS: The differences between pre- and postoperative condyle position were evaluated using measurements taken from preoperative CT scans and compared to CT scans made a minimum of 6 months postoperatively. The positional changes in both the axial and sagittal planes were measured and compared. The recovery of mandibular function was evaluated by measuring maximal interincisal opening (MIO). The results revealed that condylar positional changes after BSSO in both groups were minimal and not significantly different for all three dimensions measured. The recovery of mandibular function was faster in the group G2 than in the group G1. Mandibular function reached almost preoperative level in 6-12 months postoperatively in both groups. CONCLUSION: The results demonstrated that following BSSO, only insignificant condylar displacement and functional changes occurred within 6 to 12 months postoperatively (Tab. 4, Fig. 2, Ref. 47).

Does orthognathic surgery affect mandibular condyle position? A retrospective study.

PURPOSE: The aim of this study is to analyze mandibular condyle position changes after bilateral sagittal split osteotomy (BSSO) and bimaxillary orthognathic surgery in patients operated at a single department by two surgeons in 2013-2022. Compared were groups of mandibular advancement vs setback and bimaxillary vs BSSO. METHODS: Ninety-nine subjects were included. Inclusion criteria were patients who underwent one of the BSSO or bimaxillary surgery and had CT scans performed before and after surgery. Preoperative CT scans were performed 1 day before surgery and postoperative CT scans 6-12 months afterwards. Changes in mandibular condyle position were measured in axial and sagittal planes. RESULTS: CT condylar position measurements indicated significant postoperative changes in AB angle bilaterally (p = < 0.001). In mandibular advancement and setback comparison, values were significantly lower in ABL angle values in the setback group (p = 0.011326) and significantly higher in FDR in the advancement group (p = 0.005795). There were no statistically significant changes found in BSSO and bimaxillary group comparison. CONCLUSION: Within the limitations of this study, it can be concluded that orthognathic surgery does have a moderate effect on position of the condyles, especially condylar rotation in transversal axis.

Computer Guided Generated Dual-Purpose Splint for Bilateral Sagittal Split Osteotomy.

Purpose: to evaluate the efficacy of dual-purpose computer-generated splint in guiding the proximal and the distal segment in bilateral sagittal split osteotomy. Patients and Method: It was a prospective case series study directed on 8 class III patients indicating the need of maxillary advancement and mandibular set back by bilateral sagittal split osteotomy. A CAD/CAM splint is generated to guide the distal segment to the stable maxilla and at the same time a grooved extension to engage the proximal segment ensuring the condyle in its planned position during fixation. The primary outcome was measured by calculating the difference between the pre- and post-operative condylar segment position. Results: The present study included five female patient and three male patient with mean age of 28.4 ± 5.1 years. The accuracy of the splint in positioning the mandibular proximal segment showed promising results ranging from 2.59 to 0.49. Conclusion: The dual-purpose splint introduced in this study showed satisfied results in maintaining the pre-operative condylar position while securing the distal segment in the desired plan.

Efficacy of Sagittal Split Fix Plates with Adjustable Slider for Intra-operative Identification and Correction of Condylar Sag in Sagittal Split Osteotomy-a Pilot Study.

Aim: To assess the efficacy of sagittal split plate with adjustable slider for intra-operative correction of condylar sag after bilateral sagittal split osteotomy. Subjects and Methods: Patients reporting for correction of mandibular skeletal deformities for correction with sagittal split osteotomy (SSRO) were enrolled in the study. Simple randomization method was followed for patient allocation. Patients in group A had undergone fixation sagittal split fix plates; in group B, miniplate fixation with monocortical screws was used. Occlusion was the key indicator of condylar sage that was checked at different time frames (intra-operatively T0, immediate T1, 6 months postoperatively T2). Preoperative, immediate and late postoperative (at 6 months and 1-year interval) and lateral cephalometric assessment was used to assess their stability. Results: Thirty-three patients were enrolled and 20 patients were included in the study. One patient of group A presented with central condylar sag that was identified intra-operatively and addressed immediately. All the patients in group B presented with type 2 peripheral condylar sag that was addressed by inter-maxillary elastics and orthodontics. Two patients in group A presented with mild degree of relapse at 6 months, which was comparable to the control group indicating good stability. Conclusion: Sagittal split plates appear to be efficacious for intra-operative identification and correction of condylar sag is associated with SSRO. Supplementary Information: The online version contains supplementary material available at 10.1007/s12663-022-01782-7.

Correction of Condylar Displacement of the Mandible Using Early Screw Removal following Patient-Customized Orthognathic Surgery.

OBJECTIVE: Orthognathic surgery (OGS) is a surgical intervention that corrects dentofacial deformities through the movement of maxillary and mandibular segments to achieve adequate masticatory function, joint health, and facial harmony. However, some patients present with occlusal discrepancies, condylar sag, and/or temporomandibular disorders after OGS. Various methods have been employed to solve these problems after surgery. This study aimed to evaluate the effectiveness of early screw removal in patients with occlusal discrepancies after OGS using three-dimensional cone-beam computed tomography (CBCT). METHODS: In 44 patients with dentofacial deformities, patient-customized OGSs with customized plates were performed to correct facial deformities using customized guides with computer-aided surgical simulation. Of the 44 patients, eight patients complained of occlusal discrepancies and temporomandibular disorders after OGS. These eight patients underwent screw removal under local anesthesia around four weeks. The temporomandibular joint spaces at three time points (pre-surgical, post-surgical, and after screw removal) in the sagittal and coronal planes were compared using CBCT. RESULTS: Eight patients showed an increase in joint space on CBCT images immediately after surgery (T1), but after early screw removal (T2), these spaces almost returned to their pre-surgical state, and the temporomandibular joint problem disappeared. CONCLUSIONS: The removal of screws located in the distal segment under local anesthesia between three and four weeks post-surgically may be a treatment option for patients with post-OGS occlusal discrepancies, condylar sag, and/or temporomandibular disorder.

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.

The relationship between fixation method and early central condylar sagging after bilateral sagittal split ramus osteotomy in orthognathic surgery.

PURPOSE: There is no consensus about the ideal fixation methods and their effects on the condyle after the sagittal split ramus osteotomy (SSRO) procedure. The aim of this study was to compare the incidence, clinical presentation, and treatment of condylar sagging between different fixation methods following SSRO. METHODS: Patients who underwent double jaw surgery between 2007 and 2017 were evaluated retrospectively. Mandibular fixation was maintained using one of three different options: a miniplate and a single bicortical screw, three bicortical screws, or a single bicortical screw. Some patients had malocclusion relapse in the early postoperative period due to condylar sagging, and needed reoperation. The reoperated condylar sagging patients were analysed statistically with respect to their fixation methods. RESULTS: 233 patients (134 females, 99 males) with a mean age of 23.3 years were enrolled in the study. The patients fixated with a single bicortical screw had lower revision surgery rates than those with three bicortical screws or with miniplate with a single bicortical screw (p = 0.034 and p = 0.032, respectively). These differences in central condylar sagging with a need for revision were statistically significant. CONCLUSION: Although a miniplate and a single bicortical screw and three bicortical screws are widely used after SSRO, if the priority is to avoid sagging then it seems that a single screw should be preferred for osteosynthesis.

Transoral vertical ramus osteotomy fixed with Kirschner pins.

Transoral vertical ramus osteotomy (VRO) has been condemned because the condyle has the potential to sag, and because it needs lengthy maxillomandibular fixation. We have therefore introduced a simple method of fixation, and examined its effectiveness and complications. After the osteotomy, the proximal and distal segments are trimmed to adapt to each other. Four Kirschner (K) pins 0.9mm in diameter are inserted percutaneously from the proximal to the distal segment while the condyle is positioned in the glenoid fossa. This is followed by a brief period of maxillomandibular fixation. We have reviewed the records of 95 patients who had unilateral or bilateral vertical ramus osteotomy fixed with K pins, after which the mean (SD) period of fixation was 19 (11) days. Fixation failed in two patients because excursion of the jaw was either too heavy or too early. The fixations were redone. All other fixations remained stable, including the 20 dual-jaw procedures in which VRO preceded maxillary osteotomy. The mean (SD) maximal mouth opening at final follow-up was 44 (7) mm, and in only one patient was it less than 30mm. Numbness of the lip or chin developed in seven patients, five of whom had other anterior mandibular procedures. Four patients had discomfort on palpation of the site of the pins, and one required removal. The new method was effective, and resulted in few complications within its limitations.