Stability Of Sagittal Split Osteotomy Research Articles

Ex vivo biomechanical stability of sagittal split osteotomy with lingual bad splits

Ex vivo biomechanical stability of sagittal split osteotomy with lingual bad splits

Does Fixation Method Affect Stability of Sagittal Split Osteotomy and Condylar Position?

Fixation methods are important for condylar position and stability in sagittal split osteotomy (SSO) procedures. The aim of the present study was to compare the changes in the condylar position and stability after SSO for mandibular setback in plate fixation with monocortical screws and bicortical screws. In the present retrospective cohort study, patients who had undergone mandibular setback were studied in 2 groups. In group 1, fixation was performed using a miniplate with 4 monocortical screws. In group 2, fixation was performed using 3 bicortical screws. Cone beam computed tomography scans were taken before and immediately after the SSOs and 1year later. The condylar position was evaluated linearly (mediolateral movement in the coronal view) and angularly (condylar axis with Frankfort plane in the coronal view). The stability of the mandible was determined at the B point horizontally and vertically. A total of 50 patients were studied in 2 equal groups; however, 2 patients were lost to follow-up in group 2. A significant difference in the mediolateral changes of the condyle before and after osteotomy was detected between the 2 groups (P=.003). No difference was found between the 2 groups in the angular changes of the condyle before and after SSO in the coronal view (P=.45). Analysis of the data did not reveal any differences for vertical relapse at the B point (P=.47) or horizontal relapse between the 2 groups (P=.21). According to our results, bicortical screw fixation might be associated with more condylar displacement. However, we could not find significant differences in surgical stability between miniplate fixation with monocortical screws and bicortical screw fixation after 1year of follow-up.

In vitro comparison of 1.5 mm vs. 2.0 mm screws for fixation in the sagittal split osteotomy

Purpose Numerous “ in vitro” investigations have been conducted to evaluate the role of screw size and pattern in determining optimal resistance to deformation, often these have been controversial. The aim of this study was to evaluate the effect of screw size and insertion technique on the stability of sagittal split osteotomies. Materials and methods This study used twenty polyurethane replicas of human hemimandibles with a prefabricated sagittal split ramus osteotomy (SSRO). The hemimandibles were stabilized with 1.5 mm and 2.0 mm titanium screws inserted in an inverted L configuration. All specimens were tested to determine the strength and stability of the fixation. Results In all cases there was failure of the synthetic bone before there was any evidence of screw failure. There were no significant differences in the load necessary to make the construct fail between the 1.5 or 2.0 mm screw sizes. Conclusion There was no statistically significant difference between the strengths achieved with screws of 1.5 and 2.0 mm diameters for fixation of SSRO performed in synthetic mandibles. There was no fracture of the 1.5 mm or 2.0 mm diameter screws in any of the tests. 1.5 mm diameter screws in an inverted L pattern have as much stability and mechanical resistance as a 2.0 mm screw, may be safely used for this procedure.

Stability of sagittal split osteotomies.

Stability of sagittal split osteotomies.

Stability of sagittal split osteotomies: A comparison of three stabilization techniques

The objective of this study was to retrospectively evaluate stability of mandibular advancement after bilateral sagittal split osteotomies were performed. Three different fixation and immobilization protocols were examined. Thirty-three patients were evaluated with preoperative, immediate postoperative, and long-term (mean, 13 months) lateral cephalometric radiographs. The patients were divided into three groups: group 1 ( n = 10) had nonrigid internal fixation and 6 weeks of maxillomandibular fixation, group 2 ( n = 12) had rigid internal fixation and immediate postoperative function, and group 3 ( n = 11) had rigid internal fixation with maxillomandibular fixation for a mean of 14 days. Group 3 had the least amount of sagittal and vertical relapse. Differences in sagittal relapse were statistically significant between groups 1 and 3. Group 2 demonstrated greater sagittal relapse than did group 3, although the result was not statistically significant. This study suggests that the use of rigid internal fixation with a period of maxillomandibular fixation appears to be more stable than nonrigid internal fixation with maxillomandibular fixation or rigid internal fixation without maxillomandibular fixation.

The effect of screw size and insertion technique on the stability of the mandibular sagittal split osteotomy

The effect of screw size and insertion technique on the stability of sagittal split osteotomies was evaluated on 10 cadaver mandibles. The mandibles were osteotomized, and stabilized with either 2.0- or 2.7-mm stainless steel screws inserted as lag screws or position screws. All specimens were tested on an MTS servohydraulic testing machine (MTS Systems, Inc, Minneapolis, MN) to determine the strength and stability of the fixation. There were no statistically significant differences between the strengths achieved with the different screw sizes or fixation techniques. The primary variable that determined stability seemed to be the quality of the underlying bone.