下颌角弧形截骨线的设计与临床意义

目的：为下颌角截骨术设计安全、美观的弧形截骨线。方法将150例（300侧）成人离体下颌骨的下颌管暴露。观测下颌管的走行特点;测量下颌管关键点距下颌缘的距离;观测下颌孔与下牙槽弓的位置关系;依据观测结果设计出符合个性化需求的弧形截骨线。结果下颌管关键点A1、B1、C1、D1、E1距下颌缘的距离分别为（14．02±2．23）mm、（21．06±3．90）mm、（14．08±3．68）mm、（13．60±2．80）mm、（14．55 ± 3．34）mm ,各点的最大截骨宽度分别为（10．05 ± 4．00）mm、（15．06±2．88）mm、（8．08±3．88）mm、（6．09 ± 3．45）mm、（7．06±3．56）mm ;下颌孔与下牙槽弓位于同一平面的概率为96％;截骨线的后端A点不应高于下颌孔平面,3条截骨线的前端C点、D点、E点分别是经下颌支前缘、下颌牙M 2位、下颌牙P4位向下所引垂线与下颌缘的交点。结论下颌角弧形截骨线的设计适应个性化需求,符合解剖学特征和美学要求,具有标志明确、易于操作、安全性高、术后效果好的优点。     

Long-term functional outcomes after an external femoral derotation osteotomy in individuals with cerebral palsy

BackgroundIt is unknown how a femoral derotation osteotomy (FDO) during childhood affects functional outcomes in adulthood among individuals with bilateral cerebral palsy (CP).Research questionsHow do long-term functional outcomes after an FDO compare to matched individuals who did not have an FDO? How do outcomes change over time?MethodsWe queried the gait laboratory database for individuals who underwent an external FDO in childhood and were currently ≥25 years old. Participants returned for a long-term analysis (gait, physical examination, functional tests, imaging, questionnaires). The matched non-FDO group included only individuals in Gross Motor Function Classification System levels I-II, yielding three groups (non-FDO I-II, FDO I-II, FDO III-IV).ResultsSixty-one adults (11 non-FDO, 34 FDO I-II, 16 FDO III-IV) returned 13–25 years after baseline (non-FDO) or surgery (FDO). The non-FDO and FDO I-II groups were matched at baseline on most variables, except the FDO group had weaker hip abductors. At long-term, groups were similar on gait variables (median long-term hip rotation [primary outcome], non-FDO: −4°, FDO I-II: −4°, FDO III-IV: −5°), hip abduction test, fear of falling, and most pain measures despite anteversion being 29° greater in the non-FDO group. The FDO I-II group reported more falls than the non-FDO group. All groups improved on hip rotation, foot progression, and hip abductor strength. Speed and step length decreased/tended to decrease for all three groups. Hip abduction moment and gait deviation index did not change. Improvements in the FDO groups were maintained from short- to long-term.SignificanceThese results challenge the notion that an FDO is necessary to correct mean stance hip rotation for higher functioning individuals since nearly identical results were achieved by adulthood in the non-FDO I-II group. However, an FDO provides improvement earlier and maintenance from short- to long-term. This should factor into the shared decision-making process.     

The effect of an intramedullary self-reinforced poly-L-lactide (SR-PLLA) implant on growing bone with special reference to fixation properties. An experimental study on growing rabbits

Polylactic acid (PLA) is a synthetic biodegradable material. The self-reinforced implants made of poly-L-lactic acid (SR-PLLA) were manufactured of biodegradable polymeric matrix reinforced with fibres of the same material. The purpose of this study was to find out the effect of an intramedullary SR-PLLA implant on growing bone and its applicability to the fixation of a femoral shaft osteotomy in a growing rabbit. In seven rabbits 6 weeks of age a SR-PLLA implant 2.0 mm in diameter and 50 mm in length was introduced into the intramedullary cavity of the right femur. A proximal femoral shaft osteotomy of the right femur was made in another ten 6-weeks-old rabbits. After accurate reduction, fixation of the osteotomy was achieved with an intramedullary 2.0 mm by 50 mm SR-PLLA-rod. The follow-up times were 6 and 28 weeks. An intramedullary SR-PLLA-rod neither caused any disturbance of the bone growth nor abnormalities of the peripheral blood cell counts. Solid union of the osteotomy was seen in six weeks after fixation with SR-PLLA implant.     

Accuracy of midface advancement using patient-specific surgical guides and pre-bent plates versus conventional interocclusal wafers and conventional plate fixation in quadrangular Le Forte II osteotomy. A randomised controlled trial

The aim of this study was to assess the accuracy of quadrangular Le Fort II osteotomy and midface advancement utilising digitally fabricated surgical guides with pre-bent plates compared with conventional interocclusal wafers. Twenty patients with midface deficiency were allocated randomly to two groups: patient-specific surgical guides and pre-bent titanium miniplates were utilised in the study group, while conventional interocclusal wafers with intraoperatively adapted titanium miniplates were utilised in the control group. The accuracy of virtual planning was assessed in both groups using computed tomography (CT). Both groups showed accurate transfer of the plan, but the computer-guided group showed significantly greater accuracy and a shorter surgical time than the conventional group. The use of patient-specific surgical guides and pre-bent plates represents a promising computer-guided approach especially for inexperienced surgeons. Nevertheless, a major limitation is increased overall cost compared with the conventional approach.     

Variables associated with stability after Le Fort I osteotomy for skeletal class III malocclusion

The purpose of this study was to assess skeletal stability and predictors of relapse in patients undergoing an isolated Le Fort I osteotomy. A retrospective cohort study of 92 subjects undergoing Le Fort I osteotomy for Class III malocclusion was implemented. Predictor variables were demographic and perioperative factors. The primary outcome variable was postoperative skeletal position with relapse defined as >2 mm sagittal and/or vertical change at A-point on serial lateral cephalograms at immediate postoperative, 1 year, and latest follow-up time points. Mean advancement at A-point was 6.28 ± 2.63 mm and mean lengthening was 0.92 ± 1.76 mm. Eight subjects (8.70%) had relapse (>2 mm) in the sagittal plane, and two subjects (2.17%) in the vertical plane. No subjects required reoperation for relapse as overbite and overjet remained in an acceptable range due to dental compensation. In regression analysis, magnitude of maxillary advancement was an independent predictor of relapse in the sagittal plane (P = 0.008). There were no significant predictors of relapse in the vertical plane. This study suggests that isolated Le Fort I osteotomy for correction of skeletal Class III malocclusion is a stable procedure and that greater advancement is an independent risk factor for sagittal relapse.     

Use of a ‘low and short’ medial cut limits sagittal ramus osteotomy interferences

The traditional ‘high and short’ medial cut of the sagittal ramus osteotomy (Hunsuck modification) is a frequent cause of lingual plate interferences in patients undergoing mandibular yaw or cant corrections. We describe how the modified ‘low and short’ medial cut of the sagittal ramus osteotomy reduces lingual plate interferences with improved passive alignment of the osteotomy segments.     

Relapse-related factors of Le Fort I osteotomy in cleft lip and palate patients: A systematic review and meta-analysis

A systematic review search was based on the PICOS approach, as follows: population: cleft lip and palate patients; intervention: Le Fort I osteotomy; comparator: different surgical protocols; outcome: stability, recurrence or surgical complications; study designs: only case reports were excluded from the review. No restrictions were placed on language or year of publication. Risk of bias was analyzed, heterogeneity was assessed, and subgroup analysis was performed using a level of significance of 1% (p = 0.01).The search identified 248 citations, from which 29 studies were selected and a total of 797 patients enrolled. The level of agreement between the authors was considered excellent (k = 0.810 for study selection and k = 0.941 for study eligibility). Our results reported a mean maxillary advancement of 5.69 mm, a mean vertical downward/upward of 2.85/−2.02 mm and a mean clockwise rotation of 4.15°. Greater surgical relapse rates were reported for vertical downward movement (−1.13 mm, 39.6%), followed by clockwise rotation (−1.41°, 33.9%), sagittal (−0.99 mm, 17.4%) and vertical upward (0.11 mm, 5.4%) movements. No relevance was found regarding the type of cleft, the type of Le Fort I osteotomy, concomitant bone grafting, surgical overcorrection, postoperative rigid or elastic intermaxillary fixation, or retention splint.Study limitations were heterogeneity and the low number of high-quality studies. In spite of reported high relapse rates, Le Fort I osteotomy for maxillary reposition is the first-choice procedure for selected cleft lip and palate patients in whom extensive maxillary movements are not required, because of its safety and its three-dimensional movement versatility in one-step surgery. Otherwise, distraction osteogenesis should be considered as the gold standard treatment.