Alignment and mechanics evaluation for a compaction broach stem versus a blade style proximal press fit stem using 3-Dimensional planning.

Three-dimensional (3D) preoperative planning tools can be used to help plan and compare component alignment scenarios for different total hip arthroplasty systems to ultimately improve postoperative outcomes and patient satisfaction. The objective of this study is to use 3D preoperative planning tools based on patient-specific bone models to compare two different stem designs, specifically a compaction broach stem and a proximal press fit stem. The planner uses patient-specific proximal femoral bone morphology to suggest a specific implant size and placement. The planner then allows for preoperative predictions of component head positioning, stem fit within the canal, and potential cortical bone reaming that must be done, as well as postoperative predictions of stability and mechanics. The stems were evaluated to determine the accuracy of stem placement, the theoretical volumetric bone removal/reaming required to achieve a desired fit, and the associated postoperative mechanics. This study demonstrated that there was a difference in component alignment and predicted postoperative mechanics between a compaction broach stem and a press fit stem, with the compaction broach stem allowing for more accurate alignment with less required bone removal, resulting in improved postoperative stability and mechanics. This study also demonstrated that much of the stem misalignment for both systems occurred in the anterior/posterior direction. Overall, 3D preoperative planning offers significant benefits and novel intraoperative insight, and the industry should continue to enhance their THA preoperative planning tools.

Propensity-matched comparison of postoperative stability and visual outcomes of toric intraocular lens with or without a capsular tension ring and updated meta-analysis.

PURPOSE: To assess the contribution of capsular tension ring (CTR) to postoperative stability and visual outcomes of a plate-haptic toric intraocular lens (IOL). METHODS: This prospective cohort study was performed among patients underwent toric IOL (AT TORBI 709 M) implantation with or without CTR at the Eye and ENT hospital between April 2020 and November 2021. Propensity score matching (PSM) was performed to balance baseline factors. Postoperatively, uncorrected distance visual acuity (UCVA) and residual astigmatism, as well as IOLs' rotation, tilt, and decentration, were analyzed. Grouped multiple linear regression analysis was used to model predictive factors of rotation in each group. Additionally, a meta-analysis of data from 4 publications (284 eyes) and current study was performed to evaluate the effect of CTR co-implantation on toric IOL rotation. RESULTS: After PSM, 126 eyes from each group were included for further analysis. Postoperatively, UDVA was 0.31 ± 0.38 logMAR and 0.27 ± 0.36 logMAR in the CTR and NCTR groups, respectively (P = 0.441), and residual astigmatism was 0.75 ± 0.52 D and 0.86 ± 0.65 D, respectively (P = 0.139). The rotation of toric IOL was significantly smaller in the CTR group than in the NCTR group (4.63 ± 6.27 vs. 10.93 ± 16.05 degrees, P < 0.001). The regression models of the two groups and the coefficients of LT were significantly different (P < 0.001 and P = 0.001, respectively). Furthermore, the meta-analysis confirmed that CTR co-implantation reduced toric IOL rotation (MD, - 1.59; 95% CI, - 3.10 to - 0.09; P = 0.038). CONCLUSION: CTR enhances rotational stability of toric IOL by reducing the impact of LT, and CTR co-implantation is recommended in patients with lens thickness (LT) ≥ 4.5 mm, white-to-white (WTW) ≥ 11.6 mm, or high preexisting astigmatism.

Stability of pre-orthodontic orthognathic surgery depending on mandibular surgical techniques: SSRO vs IVRO.

The aim of this retrospective cohort study was to evaluate the postoperative stability of sagittal split ramus osteotomy (SSRO) and intraoral vertical ramus osteotomy (IVRO) in pre-orthodontic orthognathic surgery (POGS) for skeletal Class III malocclusion. Thirty-seven patients (SSRO, n = 18; IVRO, n = 19) who underwent bimaxillary surgery were divided into two groups according to the type of surgery. During the postoperative period, there were no significant differences in anterior and superior movements of the mandible at point B between the two groups, but occlusal plane angle of the SSRO group significantly decreased more than that of the IVRO group (P = 0.003). Only the SSRO group showed a linear relationship between the amount of postoperative horizontal and vertical movements of the mandible (R(2) = 0.254; P = 0.033), indicating that the amount of postoperative upward movement of the mandible increased as the amount of postoperative forward movement increased (r = -0.504; P = 0.033). The mandible after SSRO in POGS rotated counterclockwise due to rigid fixation between two segments, whereas the mandible after IVRO without rigid fixation in POGS moved mainly in a superior direction. These differences must be considered before surgery to ensure postsurgical stability for patients with mandibular prognathism.

Postoperative stability for surgery-first approach using intraoral vertical ramus osteotomy: 12 month follow-up.

The aim of this study was to evaluate the postoperative stability of the surgery-first approach using intraoral vertical ramus osteotomy (IVRO). We retrospectively studied a sample derived from the patients who were treated by the surgery-first approach using a LeFort I osteotomy and IVRO for correction of class III dentofacial deformity from 2008 to 2012. Lateral cephalograms taken preoperatively and 2 days, 6 months, and 12 months postoperatively were traced, and the skeletal and dental variables at different time points were analysed. The study sample comprised 37 subjects, mean (SD) age 23 (4) years. The mean (SD) total duration of treatment including postoperative orthodontics was 14 (6) months, and surgical movement of the maxillary A point was 0.75 (1.3)mm anteriorly, and 0.21 (1.79)mm superiorly. The surgical change in the position of the maxillary first molar was 1.01 (1.57)mm superiorly. The mean (SD) movement of mandible was 11.15 (5.4)mm posteriorly at pogonion and 1.02 (1.79)mm inferiorly at menton. There were no significant change in maxillary skeletal variables during the first year postoperative period. The surgical relapse of mandible at pogonion was 0.63 (2.31) mm anteriorly (p=0.01), however, the relapse in superior direction at menton was 2.86 (1.39) mm with statistical significance (p=0.01). The total duration of orthodontic treatment with surgery-first was roughly 5 months shorter than conventional preoperative and postoperative orthodontic treatment. The surgery-first approach using IVRO is effective and predictable, and shortens the overall duration of treatment. Anterior relapse of the mandible was less than 1mm, and increased superior relapse can be compensated for with appropriate preoperative planning to provide a reliable outcome. This study was limited to 12 months' follow-up, and a long term follow-up study is indicated.

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.

Postoperative stability following bilateral intraoral vertical ramus osteotomy based on amount of setback.

Our aim was to evaluate the postoperative stability associated with differing degrees of mandibular setback and their relations after intraoral vertical ramus osteotomy (IVRO). We planned a retrospective cohort study of 94 patients (mean age (range) 23 (18-46) years) selected from a larger group who had been diagnosed with mandibular prognathism with or without facial asymmetry and who had mandibular setback by IVR osteotomy from 2004 to 2009. The preoperative, 7-day, and 12-month postoperative lateral cephalographs were measured to find out the degree of movement, and the vertical and horizontal positions of menton and pogonion were compared at different time points to measure stability. The mean (SD) setback was 10.5 (5.1) mm, with 0.8 (1.1) posterior relapse at 12 months. The mean surgical change of menton vertically was 3.0 (3.0) mm superiorly, with an additional 1.3 (1.05) mm at 12 months. The amount of posterior relapse was less as the amount of setback increased but not significantly so. The amount of setback therefore has minimal effects on anterior relapse, and cannot be considered singly as a variant that affects the degree of stability. The risk of anterior relapse is low even with a substantial degree of mandibular setback, so overcorrection is not necessary with the IVR osteotomy.

Effect of perioperative buccal fracture of the proximal segment on postoperative stability after sagittal split ramus osteotomy.

OBJECTIVES: Buccal fracture of the mandibular proximal bone segment during bilateral sagittal split ramus osteotomy (SSRO) reduces the postoperative stability. The primary aim of this study is to evaluate the effect of this type of fracture on bone healing and postoperative stability after mandibular setback surgery. MATERIALS AND METHODS: Ten patients who experienced buccal fracture during SSRO for mandibular setback movement were evaluated. We measured the amount of bone generation on a computed tomography scan, using an image analysis program, and compared the buccal fracture side to the opposite side in each patient. To investigate the effect on postoperative stability, we measured the postoperative relapse in lateral cephalograms, immediately following and six months after the surgery. The control group consisted of ten randomly-selected patients having a similar amount of set-back without buccal fracture. RESULTS: Less bone generation was observed on the buccal fracture side compared with the opposite side (P<0.05). However, there was no significant difference in anterior-posterior postoperative relapse between the group with buccal fracture and the control group. The increased mandibular plane angle and anterior facial height after the surgery in the group with buccal fracture manifested as a postoperative clockwise rotation of the mandible. CONCLUSION: Bone generation was delayed compared to the opposite side. However, postoperative stability in the anterior-posterior direction could be maintained with rigid fixation.