Transoral placement of rigid fixation following sagittal ramus split osteotomy

The aim of this study was to perform a three-dimensional evaluation of the skeletal relapse of the proximal and distal mandibular segments following isolated bilateral sagittal split osteotomy advancement surgery. One hundred consecutive patients (mean age 25.8 ± 11.7 years), comprising 65 female patients (mean age 26.4 ± 12.1 years) and 35 male patients (mean age 24.6 ± 11.0 years) requiring mandibular advancement without genioplasty, were enrolled prospectively in the study. Cone beam computed tomography scans were acquired for each patient at three time-points: preoperatively, immediately (1–6 weeks) after surgery, and 1 year after surgery. A validated tool was utilized to assess the surgical movement and relapse. Based on percentage, the majority of the distal and proximal translational and rotational movements relapsed within the range of ≤2 mm and ≤2°. The distal segment revealed a significant relapse in a posterior, inferior, and clockwise pitch direction. Both left and right proximal segments showed a significant translational relapse in the medial, posterior, and superior direction. Amongst the rotational parameters, proximal segments relapsed significantly in clockwise pitch, clockwise roll, and counterclockwise yaw direction. Overall, both distal and proximal bone segments showed a clinically acceptable translational and rotational stability. The proximal segments torqued towards their original position with a reduction of flaring.

Bilateral sagittal split osteotomy is one of the most frequently performed operations in orthognathic surgery. The health of the temporomandibular joint (TMJ) is an important prerequisite for its functionality. The aim of this finite element study was to assess the developed stresses during mouth opening after bilateral sagittal split osteotomy. Different osteotomy gap widths and disc positions were evaluated.

Computed tomography and magnetic resonance data of a dentulous cadaver head were used in order to create two finite element models simulating split distances of 5 and 10 mm, respectively. The fixation of the distal and proximal segments was made by a four- or a six-hole titanium mini plate and four monocortical screws respectively. For both models, three different situations of the articular disc were created: a physiological disc position, anterior disc displacement and posterior disc displacement. The mandible was vertically displaced in the midline in order to simulate a mouth opening of 20 mm.

The simulation showed high stresses in the area of the titanium plates (up to 850 MPa), implying an increased risk of material failure. High stresses were found within the discs in the models with normal disc position and anterior disc displacement as well (up to 8 MPa), indicating a higher risk of developing craniomandibular disorders. Regarding the stresses within the fixation screws, the highest values were recorded in the area of the upper thread.

The degree of mandibular advancement after a bilateral sagittal split osteotomy affects the stress balance in the mandible and the articular discs during mouth opening.

Orthognathic surgery may affect or cause temporomandibular joint (TMJ) complaints. This study evaluated the need for TMJ surgery after orthognathic surgery.

A retrospective cohort study was carried out on 630 consecutive patients undergoing at least a Le Fort I or bilateral sagittal split osteotomy (BSSO). The mean follow-up time was 2,3 years. Clinical, surgical and radiographic findings were collected.

Ten of the 630 patients (1.6%) had additional arthroscopic TMJ-surgery in one (9) or in both (1) joints because of internal derangement, resistant to conventional therapy. Only 4/10 patients had successful outcomes following arthroscopic surgery. One patient with unsuccessful outcome required multiple additional open TMJ-surgeries, all remaining ineffective to relieve pain and restricted mouth opening. If arthroscopy failed to relieve symptoms (5/10 patients), further conservative management was opted. Arthroscopy seemed effective mainly in patients without pre-existing TMJ complaints.

A further five of the 630 patients (0.8%) required more treatment because of bilateral postoperative condylar resorption, but none of them required TMJ-surgery.

In contrast to patients with bilateral condylar resorption where the skeletal relapse remained the issue of concern, patients with internal derangement/osteoarthrosis exhibited major occlusal changes in one patient only (1/10), leaving the TMJ complaints as the main concern.

The objectives of this study were to analyze outcomes with miniplates in orthognathic surgery and define risk factors resulting in plate removal.

Clinical files of 570 orthognathic surgery patients operated between 2004 and 2009 were reviewed: 203 had a bimaxillary operation, 310 a lower jaw osteotomy, and 57 an upper jaw osteotomy. Age, sex, and jaw movement were analyzed. Reasons for hardware removal were recorded.

Hardware was removed in 157 patients (27.5%). Seventy-eight patients (13.7%) needed removal because of plate-related infection; 66 (11.6%) because of clinical irritation; 5 (0.9%) for dental implant placement; and 8 (1.4%) for other reasons. Average time between operation and removal was 9.9 months. More women (31.7%) than men (20.3%) had plates removed, but age was not a factor except with infection.

More than a quarter of patients developed complications from plates and screws, necessitating their removal, and infection occurred in 13.7%. Prompt removal constituted adequate management.

The objectives of this study were to determine the incidence of bad splits in sagittal split osteotomies (SSOs), performed at the same hospital, and if the occurrence was reduced over time because of technical progress and/or surgical experience. Bad splits were defined as buccal or lingual plate fractures.

The files of all patients (n = 1008) who underwent bilateral or unilateral SSO between October 1989 and October 2009 were reviewed retrospectively.

A bad split occurred in 14 SSO sites (14 of 2005 sites). No bilateral bad splits occurred. There was no notable decrease of bad splits over the 20 years. All bad splits were resolved perioperatively by plate-osteosynthesis without the additional need of intermaxillary fixation. All patients with a bad split had a good and functional occlusion 6 months postoperatively. No infections occurred at the site of the bad splits. No bad splits occurred in patients younger than 20 years. No particular type of dental-facial deformity, or skeletal class according to the Angle's classification could be correlated with cases of bad splits as a predisposing risk factor.

Even if precautions are taken, a bad split can occur during SSO of the mandible. This complication is manageable because of its low incidence (0.7 % of all SSOs) and uneventful healing. A significant decrease in incidence did not occur during the 20-year period, and neither technical progress nor the surgeon's experience further reduced the incidence of bad splits.

The purpose of the present study was to evaluate the clinical application of resorbable and nonresorbable plates for correction of facial asymmetry.

A total of 272 patients who had undergone orthognathic surgery were enrolled. The site of osteotomy was fixed using a nonresorbable plate in group I (n = 152) and using a resorbable plate in group II (n = 120). The postoperative complications included postoperative anterior open bite, infection, temporomandibular joint dysfunction, and postoperative relapse. The incidence of all complications was examined.

The surgical outcome was successful in 269 patients (98.89%). Of the 152 patients with a titanium plate, 13 (8.6%) developed complications. Of the 120 patients with a resorbable plate, 22 (18.3%) developed complications. A greater degree of postoperative open bite and a trend toward relapse were observed in patients' cases in which an absorbable fixation plate was used. Postoperative infection occurred in patients with an absorbable fixation plate.

On the basis of these data, we have concluded that an absorbable fixation plate should be used instead of a titanium fixation plate in indicated patients.