Outcome Assessment of Z-shaped Osteotomy in the Management of Humeral Shaft Nonunion Secondary to Failed Plate Osteosynthesis

Restoration of fracture alignment by osteotomy is crucial for the management of humeral nonunion. In the present study, we introduced a new way of osteotomy (Z-shaped) in treating humeral shaft nonunion secondary to failed plate osteosynthesis. Clinical data of 24 patients with humeral shaft nonunion following implant failure (from 2010 to 2014) were retrospectively evaluated. These patients underwent Z-shaped osteotomy in revision surgery after the initial surgery, plate osteosynthesis, was failed. Outcomes were evaluated using visual analogue scale (VAS) and Constant and Murley score. Repeated analysis of variance (ANOVA) was used for statistical analysis. Patients were followed up for a minimum of 24 months (26.83±4.33 months). The operative time was 102.33±10.16 min, and hospital stay averaged 9.75±2.13 days. All patients achieved clinical union at the latest follow-up. Complications included radial palsy (n=1) and superficial wound infection (n=1). The postoperative VAS scores decreased significantly compared to preoperative score (F=257.99, P<0.01). Constant and Murley score increased and reached 81.33±0.95 at 24 months' follow-up 0=247.35, P<0.01). Among all the cases, 15 cases were graded as "excellent", and 9 as "good". In conclusion, Z-shaped osteotomy was easy to perform, and it provided additional medial support with more bone contact areas. Revision surgery using locking plate and Z-shaped osteotomy achieved high union rate and improved functional outcome. It was a reasonable and safe option for treating humeral nonunion following implant failure.

Evaluation of “J”-shaped Uterine Incision during Caesarean Section in Patients with Placenta Previa:A Retrospective Study

This study evaluated the efficacy and safety of ＂J＂-shaped uterine incision for caesarean section for patients diagnosed with placenta previa. A total of 55 consecutive cases of placenta previa treated in Union Hospital were retrospectively analyzed over a period of two years and 10 months. The subjects were divided into two groups with respect to the uterine incision. Twenty-four pregnant women with placenta previa who were indicated for caesarean section underwent the procedure using a new ＂J＂-shaped uterine incision and 31 pregnant women with placenta previa received caesarean section that used the traditional transverse incision. The two groups were compared in terms of operation time, estimated blood loss, infant expulsion time, exhaust time and postoperative recovery. Meanwhile, comparison was also made in neonatal clinical data between the two groups. Compared with the ＂J＂-shaped incision group, the traditional incision group had a lower Apgar scores （P〈0.05）. However, there existed no statistically significant differences in the overall time of operation and postoperative period of breaking wind （P〉0.05）. It is concluded that, with caesarean section for placenta previa patients, the ＂J＂-shaped uterine incision significantly decreases intraoperative blood loss and facilitates the fetal delivery.

Shortening turn-on delay of SiC light triggered thyristor by7-shaped thin n-base doping profile

A new 4 H–SiC light triggered thyristor（LTT） with 7-shaped thin n-base doping profile is proposed and simulated using a two-dimensional numerical method. In this new structure, the bottom region of the thin n-base has a graded doping profile to induce an accelerating electric field and compensate for the shortcoming of the double-layer thin n-base structure in transmitting injected holes. In addition, the accelerating electric field can also speed up the transmission of photongenerated carriers during light triggering. As a result, the current gain of the top pnp transistor of the SiC LTT is further increased. According to the TCAD simulations, the turn-on delay time of the SiC LTT decreases by about 91.5% compared with that of previous double-layer thin n-base SiC LTT. The minimum turn-on delay time of the SiC LTT is only 828 ns,when triggered by 100 mW/cm^2 ultraviolet light. Meanwhile, there is only a slight degradation in the forward blocking characteristic.

Unicompartmental knee arthroplasty vs high tibial osteotomy for knee osteoarthritis:A comparison of clinical and radiological outcomes

BACKGROUND Unicompartmental knee arthroplasty(UKA)and high tibial osteotomy(HTO)are well-established operative interventions in the treatment of knee osteoarthritis.However,which intervention is more beneficial to patients with knee osteoarthritis remains unknown and a topic of much debate.Simultaneously,there is a paucity of research assessing the relationship between radiographic parameters of knee joint alignment and patient-reported clinical outcomes,preoperatively and following HTO or UKA.AIM To compare UKAs and HTOs as interventions for medial-compartment knee osteoarthritis:Examining differences in clinical outcome and investigating the relationship of joint alignment with respect to this.METHODS This longitudinal observational study assessed a total of 42 patients that had undergone UKA(n=23)and HTO(n=19)to treat medial compartment knee osteoarthritis.Patient-reported outcome measures(PROMs)were collected to evaluate clinical outcome.These included two disease-specific(Knee Injury and Osteoarthritis Outcome Score,Oxford Knee Score)and two generic(EQ-5D-5L,Short Form-12)PROMs.The radiographic parameters of knee alignment assessed were the:Hip-knee-ankle angle,mechanical axis deviation and angle of Mikulicz line.RESULTS Statistical analyses demonstrated significant(P<0.001),preoperative to postoperative,improvements in the PROM scores of both groups.There were,however,no significant inter-group differences in the postoperative PROM scores of the UKA and HTO group.Several significant correlations associated a more distolaterally angled Mikulicz line with worse knee function and overall health preoperatively(P<0.05).Postoperatively,two clusters of significant correlations were observed between the disease-specific PROM scores and knee joint alignment parameters(hip-knee-ankle angle,mechanical axis deviation)within the HTO group;yet no such associations were observed within the UKA group.CONCLUSION UKAs and HTOs are both efficacious operations that provide a comparable degree of clinical benefit to patients with medial compartment knee osteoarthritis.Clinical outcome has a limited association with radiographic parameters of knee joint alignment postoperatively;however,a more distolaterally angled Mikulicz line appears associated with worse knee function/health-related quality of life preoperatively.

Learning curve for a surgeon in robotic pancreaticoduodenectomy through a“G”-shaped approach:A cumulative sum analysis

BACKGROUND Robotic pancreaticoduodenectomy(RPD)can achieve similar surgical results to open and PD;however,RPD has a long learning curve and operation time(OT).To address this issue,we have summarized a surgical path to shorten the surgical learning curve and OT.AIM To investigate the effective learning curve of a“G”-shaped surgical approach in RPD for patients.METHODS A total of 60 patients,who received“G”-shaped RPD(GRPD)by a single surgeon in the First Hospital of Shanxi Medical University from May 2017 to April 2020,were included in this study.The OT,demographic data,intraoperative blood loss,complications,hospitalization time,and pathological results were recorded,and the cumulative sum(CUSUM)analysis was performed to evaluate the learning curve for GRPD.RESULTS According to the CUSUM analysis,the learning curve for GRPD was grouped into two phases:The early and late phases.The OT was 480±81.65 min vs 331±76.54 min,hospitalization time was 22±4.53 d vs 17±6.08 d,and blood loss was 308±54.78 mL vs 169.2±35.33 mL in the respective groups.Complications,including pancreatic fistula,bile leakage,reoperation rate,postoperative death,and delayed gastric emptying,were significantly decreased after this surgical technique.CONCLUSION GRPD can improve the learning curve and operative time,providing a new method for shortening the RPD learning curve.

A Novel Open C-shaped Molar Band for Orthodontic Applications： Mechanical Characterizations and Clinical Trials

To evaluate the retention properties of the novel ‘C＇-shaped molar bands at a laboratory level. Resin-modified glass ionomer cement（RMGIC） was used as a luting agent for the novel C-shaped molar band. The mechanical properties of the band were examined and the retention performance was characterized in the mesial, distal and vertical directions. A clinical trial was conducted using a spilt-mouth design on 50 patients. The novel C-shaped molar bands fit most molars without a repeated try-in process.The use of both nanoHA coating and RMGIC enhanced the tensile（8.00 ± 1.8 MPa） and shear strengths（27.17 ± 8.6 MPa） of the molar bands, leading to high retention in vertical, mesial and distal directions（ p 〈 0.001）. In clinical trials, the C-shaped molar bands had a failure rate（15%） comparable to that of traditional bands, and 93% of the failed bands demonstrated an adhesive remnant index score of 0, corroborating the observation that no luting agent residue remained on the tooth surface in most cases. The novel C-shaped molar bands appear to be a promising appliance that requires further clinical investigations, and may be used effectively in orthodontics.

Knee Osteoarthritis Progression after Distal Femur Closing Wedge Osteotomy

Background: Despite the conservative treatment of tibio-femoral osteoarthritis through realignment osteotomies, the rate of total knee replacements following an osteotomy is increasing. The aim of this study was to identify the factors associated with the progression of knee osteoarthritis after a medial closing-wedge distal femoral osteotomy. Methods: Hospital-based observational study on 20 patients who underwent a medial closing-wedge distal femoral osteotomy evaluating the progression of osteoarthritis using the Kellgren and Laurence classification. The Wilcoxon test was used to compare the variation in the progressive stage of the Kellgren and Laurence classification of knee osteoarthritis preoperatively and at the final follow up. Univariate analysis made it possible to determine the factors associated with progression. The final significance threshold for statistical tests was set at 5% (p Results: Overall, the mean follow-up of 46 months ± 6.6 months, with a mean age of 43 years (range: 27 - 69 years) and a female predominance (M: F = 3/7). The progression of tibiofemoral osteoarthritis following a medial closing-wedge distal femoral osteotomy is associated with valgus or varum malalignment been a moderate valgus (OR 6.2 [1.5 - 42.7] at 95% CI;p-value = 0.02), a correction of the mechanical deviation angle with a valgus alignment (OR 2.7 [0.9 - 8.3] at 95% CI), and loss of correction (OR 3.8 [1.3 - 11.6] at 95% CI;p -value) for the lateral compartment while varus alignment (OR 1.7 [0.9 - 8.3] 95% CI, p-value = 0.05) and with rupture of the lateral cortex (OR 2.8 [1.7 - 11.5] 95% CI, p-value = 0.02) were those of the medial compartment. Conclusion: Distal femur closing wedge osteotomy does not definitively interrupt the progression of valgus knee osteoarthritis. The factors associated with the progression of this pathology are modifiable. Taking them into account when performing this surgical technique could improve the osteotomy survival curve.

Osteotomy Protocol for Implant Insertion of One Day Biotech: One Drill, One Implant

Background: Four factors determine the quality of an implantology kit: 1) Heat generated by the drills;2) Morphology of the osteotomy according to the diameter of the implant;3) Efficiency of collecting autologous bone;and 4) Osteotomy execution time. Materials and Methods: This article examines the heat produced by drills during osteotomy, focusing on the effect of the following factors: drilling technique;volume of autologous bone harvested;drilling time;implant primary stability;and the percentage of osseointegrated implants after primary healing. Discussion: The four factors mentioned above are analyzed based on the data obtained for sequential, biological, and One Drill milling techniques. Conclusions: 1) One Drill is the fastest technique for performing the osteotomy;2) All techniques stay within the biological temperature range of living bone, with the lowest increase in temperature achieved using One Drill with irrigation;3) The bone harvested showed no statistically significant differences between biological milling and the One Drill technique, both far superior to the sequential technique;and 4) There is no statistically significant difference in the number of osseointegrated implants among the three techniques analyzed.

Clinical outcomes of triceps reflecting anconeus pedicle and olecranon osteotomy approach for distal humerus intercondylar fractures

BACKGROUND The preferred treatment for distal humeral intercondylar fractures is open reduction and internal fixation.While there is consensus about the posterior approach,several posterior approaches have been developed.It is debatable as to which approach is best.AIM To compare triceps reflecting anconeus pedicle(TRAP)and olecranon osteotomy approaches for internal fixation of distal humeral intercondylar fracture.METHODS In total,40 cases of Arbeitsgemeinschaft für Osteosynthesefragen/Association of the Study of Internal Fixation type C,closed,and Gustilo type I intercondylar humeral fractures were included.Patients ranged in age from 18 years to 70 years.The patients were randomized into two groups:TRAP group and olecranon osteotomy group,with 20 cases in each.All were followed up at 6 wk,3 months,6 months,and 12 months.Functional outcomes were measured in terms of flexion-extension arc,Disabilities of Arm,Shoulder and Hand score,and Mayo Elbow Performance Score.RESULTS The mean age was 43.2 years in the TRAP group and 37.5 years in the olecranon osteotomy group.The mean operative time and mean duration of hospital stay in the TRAP group were significantly higher than in the olecranon osteotomy group(119.5 vs 111.5 min and 9.85 vs 5.45 d,respectively).The mean arc of flexion-extension,Disabilities of Arm,Shoulder and Hand score,and Mayo Elbow Performance Score were comparable without any significant difference in the groups at the 12-month follow-up(107.0 vs 106.2,18.3 vs 15.7,and 84.2 vs 86.2,respectively).Ulnar paresthesia and superficial infections were comparable in both groups(2 cases vs 3 cases and 3 cases vs 2 cases,respectively).Hardware prominence was significantly higher in the olecranon osteotomy group,mostly due to tension band wiring.CONCLUSION Both approaches were equivalent,but there is a need for further study including higher numbers of subjects and longer study duration to prove the benefits of one approach over the other.

基于α-shape与SSA-XGBoost算法的无人机点云孔洞修补

针对极限梯度提升树算法在进行无人机点云孔洞修补时核心超参数难以选取、点云孔洞修补范围识别困难以及孔洞修补精度较低等问题,提出基于麻雀搜索算法优化极限梯度提升树的点云孔洞修补方法。首先利用α-shape算法进行点云的孔洞识别,在此基础上,获取点云孔洞和周围点云的位置信息并将其作为模型的输入样本。再利用麻雀搜索算法优化极限梯度提升树算法中的核心超参数,构建SSA-XGBoost点云孔洞修补模型,并将该模型应用于无人机点云孔洞的修补中。最后将SSA-XGBoost与XGBoost、BP神经网络两组算法进行预测精度的对比。实验结果表明:SSA-XGBoost模型的预测结果相较于其它两组对比算法预测精度更高,在点云孔洞修补方面具有一定的意义。

Osteotomy combined with anterior cruciate ligament reconstruction for anterior cruciate ligament injury and biplanar deformity

BACKGROUND It has been confirmed that the increased posterior tibial slope over 12 degrees is a risk factor for anterior cruciate ligament injury,and varus deformity can aggravate the progression of medial osteoarthritis.AIM To evaluate the efficacy of modified high tibial osteotomy(HTO)and anterior cruciate ligament reconstruction(ACLR)in the treatment of anterior cruciate ligament(ACL)injuries with varus deformities and increased posterior tibial slope(PTS)based on clinical and imaging data.METHODS The patient data in this retrospective study were collected from 2019 to 2021.A total of 6 patients were diagnosed with ACL injury combined with varus deformities and increased PTS.All patients underwent modified open wedge HTO and ACLR.The degree of correction of varus deformity and the PTS was evaluated by radiography and magnetic resonance imaging.RESULTS All 6 patients(6 knee joints)were followed up for an average of 20.8±3.7 months.The average age at surgery was 29.5±3.8 years.At the last follow-up,all patients resumed competitive sports.The International Knee Documentation Committee score increased from 50.3±3.1 to 87.0±2.8,the Lysholm score increased from 43.8±4.9 to 86±3.1,and the Tegner activity level increased from 2.2±0.7 to 7.0±0.6.The average movement distance of the tibia anterior translation was 4.8±1.1 mm,medial proximal tibial angle(MPTA)was 88.9±1.3°at the last follow-up,and the PTS was 8.4±1.4°,both of which were significantly higher than those before surgery(P<0.05).CONCLUSION Modified open wedge HTO combined with ACLR can effectively treat patients with ACL ruptures with an associated increased PTS and varus deformity.The short-term effect is significant,but the long-term effect requires further follow-up.

Extracorporeal shock wave therapy in treating ischial non-union following Bernese periacetabular osteotomy:A case report

BACKGROUND Extracorporeal shock wave therapy(ESWT)is increasingly being recognized as an advantageous alternative for treating non-union due to its efficacy and minimal associated complications.Non-union following Bernese periacetabular osteotomy(PAO)is particularly challenging,with a reported 55%delayed union and 8%non-union.Herein,we highlight a unique case of ischial non-union post-PAO treated successfully with a structured ESWT regimen.CASE SUMMARY A 50-year-old patient,diagnosed with left ischial non-union following the PAO,underwent six cycles of ESWT treatment across ten months.Each cycle,spaced four weeks apart,consisted of five consecutive ESWT sessions without anesthesia.Regular X-ray follow-ups showed progressive disappearance of the fracture line and fracture union.The patient ultimately achieved a satisfactory asymptomatic recovery and bone union.CONCLUSION The results from this case suggest that this ESWT regimen can be a promising non-invasive treatment strategy for non-union following PAO.

基于局部样本增益优化的α-shape曲面拓扑重建

在曲面重建中,提高棱边特征重建精度是逆向工程和计算机辅助设计制造等领域的难点问题。采用样点的近似拓扑近邻点集作为曲面局部样本,对α-shape算法进行优化,使α-shape尺度阈值能更为准确地反映样点分布密度,从而提高α-shape曲面拓扑重建结果的正确性。样点的近似拓扑近邻点集的获取本质上是欧氏近邻点集的增益优化,使后者向邻近的稀疏区域适度延伸,从而弥补因数据分布不均匀而导致的拓扑邻域信息缺失。基于增益优化后的样点近邻点集并结合曲面重建先验知识可确定α-shape尺度阈值,使α-shape曲面拓扑重建过程中尺度阈值可自适应调整。试验表明:该算法使所得网格曲面基本不含孔洞和棱边凹痕,能更好保持棱边特征的形位精度,可减少初次过滤结果中的非流形面片,同时具有与主流Delaunay网格过滤算法相近的重建效率。

自适应α-shapes平面点云边界提取方法

针对基于微切面的点云边界提取方法在LiDAR点云边界提取中效率低,难以保证边界提取的精细度和完整性问题,提出了一种可调节滚动圆半径的α-shapes平面点云边界提取算法.该算法首先将点云数据栅格化,排除非边界点,并通过计算P点的K个邻近点平均距离和增设调节因子,设置滚动圆半径α,最后采用α-shapes算法提取点云边界.对近邻K值、点云形状和点云密度等分析,证明近邻K值与调节因子ω之间具有函数关系,及调节因子与点云密度和点云形状无关的结论.结果证明:该算法在准确提取点云边界情况下,能够快速提取完整点云边界,提高后续点云重建速度与效率,该算法具有良好的稳健性.

基于改进α-shape算法的三维点云树冠体积计算方法

为准确测量树冠体积,深入研究三维绿量和区域碳循环,针对现有点云数据测量树冠体积方法存在的高估与低估问题,提出了一种顾及点云边界密度、变阈值α-shape边界提取方法,并通过实验分析确定最优线性迭代步长和分层间距,实现了对树冠体积的精确计算。首先,对树冠点云数据进行等间距切片处理;然后,采用改进α-shape算法提取点云切片更为真实、自然的边界多边形;最后,计算切片面积和各层点云间的台体体积,并累加台体体积,获得树冠体积。实验表明:树冠体积计算的准确性与树冠内部枝叶结构和点云密度相关;无论对于高密度还是低密度树冠,采用改进α-shape算法的树冠体积计算结果不仅具有良好的稳定性,而且相较于已有其他方法更为准确,避免了Graham凸包算法的高估问题,与体元累加法相比也更利于树冠总体占用空间的计算。

髋臼周围截骨治疗对发育性髋关节发育不良骨盆矢状位倾斜的影响

背景:发育性髋关节发育不良指髋臼、股骨近端存在骨性结构畸型,可导致髋关节不稳及髋骨关节炎。髋臼周围截骨术是青少年及成年人非终末期发育性髋关节发育不良治疗的主要方式。骨盆倾斜在髋关节生物力学中发挥至关重要的作用,它決定了髋关节的应力方向。在髋关节疾病中可出现骨盆代偿性倾斜,以尽量减少髋关节的异常应力。目的:观察发育性髋关节发育不良患者行髋臼周围截骨治疗是否改变患者骨盆矢状位倾斜,并探讨髋臼覆盖对骨盆矢状位倾斜的影响。方法:回顾性分析2019年8月至2022年6月在四川大学华西医院因发育性髋关节发育不良行髋臼周围截骨的患者29例,收集患者术前及术后6个月站立位骨盆正位X射线片,测量髋关节外侧中心边缘角、通力氏角、耻骨联合到骶髂关节距离、耻骨联合到骶髂关节连线中点距离、骶骨-股骨头-耻骨角及骨盆矢状位倾斜;所有患者均于术前及术后6个月采用髋关节残疾及骨关节炎评分及Harris评分行髋关节功能评估。结果与结论:(1)与术前相比,术后6个月髋关节外侧中心边缘角、耻骨联合到骶髂关节连线中点距离、骶骨-股骨头-耻骨角均较术前显著增大(P <0.05);而通力氏角及骨盆矢状位倾斜则显著减小(P <0.05);耻骨联合到骶髂关节距离与术前无明显差异(P> 0.05);(2)术后6个月髋关节残疾及骨关节炎评分及Harris评分均较术前显著提高(P <0.01);(3)提示髋臼周围截骨显著改善了发育性髋关节发育不良患者的髋臼覆盖,且骨盆出现显著前倾改变。

膝关节单髁置换与胫骨高位截骨治疗内翻性膝骨关节炎的比较

背景:早期膝关节炎可行单髁置换和胫骨高位截骨等方法保膝治疗,但两种保膝手术在术后不同时期膝关节恢复方面是否存在差异仍需进一步探讨。目的:比较单髁置换和胫骨高位截骨治疗膝关节内翻性骨关节炎的疗效及相关并发症等方面的差异,为临床决策提供参考。方法:选择2018年9月至2022年9月南通大学附属医院行手术治疗的膝关节内翻性骨关节炎患者103例,其中86例获得1年以上随访,根据手术方法分为单髁置换组(n=49)和胫骨高位截骨组(n=37)。分别对两组患者术前及术后4周、3个月、6个月、1年的膝关节功能、疼痛以及力线纠正情况进行评估,采用美国特种外科医院膝关节评分、美国西安大略大学和麦克马斯特大学功能评分、膝关节外侧间隙变化、关节活动度、本体感觉(位置觉)、术后活动恢复速度等指标综合评判。结果与结论:(1)两组患者术前美国特种外科医院膝关节评分、美国西安大略大学和麦克马斯特大学功能评分、膝关节外侧间室大小均无显著差异;(2)术后4周单髁置换组的美国特种外科医院评分高于胫骨高位截骨组(P<0.05);在术后3,6个月,对比两组患者的改善情况,单髁置换组的美国特种外科医院评分低于胫骨高位截骨组,差异有显著性意义(P<0.05);术后6个月关节活动度屈曲值以及位置觉方面胫骨高位截骨组患者要优于单髁置换组(P<0.05);(3)在膝关节活动恢复速度方面单髁置换组要优于胫骨高位截骨组(P<0.05);(4)然而在术后1年的随访中,两组在美国特种外科医院膝关节评分、伸展方向活动度以及膝关节外侧间隙宽度变化上未见明显差异;(5)所有患者的随访数据均超过1年,且在随访期间均未发现不良并发症;(6)提示采用胫骨高位截骨治疗的内翻性膝骨关节炎患者膝关节功能恢复短期效果优于单髁置换患者,但两种方案治疗内翻性膝骨关节炎的中长期疗效无明显差异。

3D打印个体化截骨导板结合定制钢板在开放楔形胫骨高位截骨中的应用

背景:3D打印个体化截骨导板辅助开放楔形胫骨高位截骨治疗膝骨关节炎具有手术时间短、透视次数少、矫正精准度高等优点。但之前报道的截骨导板对周围软组织破坏严重、锁定钢板位置不当等问题依旧明显。目的:探究3D打印个体化截骨导板结合定制钢板辅助开放楔形胫骨高位截骨治疗膝骨关节炎的临床疗效。方法:收集20例确诊为膝骨关节炎的患者,按手术方法分为3D组和常规组,每组10例。3D组采用3D打印个体化截骨导板结合定制钢板辅助开放楔形胫骨高位截骨手术,常规组进行常规开放楔形胫骨高位截骨手术。分析比较两组患者手术时间、透视次数、切口长度,术前和术后髋膝踝角、胫骨近端内侧角、胫骨后倾角以及计划矫正角度与实际矫正角度的差值,术前和术后1,3,6个月膝关节活动度及Lysholm评分,另外记录并发症发生情况。结果与结论:①3D组患者的手术时间、透视次数少于常规组,差异有显著性意义(P<0.001);②两组患者的术后髋膝踝角、胫骨近端内侧角均较术前增大,差异有显著性意义(P<0.001),而胫骨后倾角无明显改变;3D组术后髋膝踝角、胫骨近端内侧角及胫骨后倾角与术前计划值分别相差(-0.22±0.72)°、(-0.20±0.73)°和(0.23±0.37)°,但差异均无显著性意义;3D组计划矫正度数与实际矫正度数的差值较常规组小,差异有显著性意义(P<0.05);③两组患者术后膝关节活动度及Lysholm评分均逐步升高(P<0.001);3D组术后1,3个月的膝关节活动度及术后1个月的Lysholm评分优于常规组,差异有显著性意义(P<0.05);两组患者术后3个月的Lysholm评分、术后6个月的膝关节活动度及Lysholm评分差异无显著性意义(P>0.05);④两组患者均无并发症发生;⑤上述结果说明3D打印个体化截骨导板结合定制钢板辅助和常规方法均有良好的临床疗效,但前者的手术时间更短,透视次数更少,术后膝关节功能恢复更快;并且3D打印个体化截骨导板可精准实现术前规划。

数字化精准全膝关节置换与传统置换方法的短期效果对比

背景:传统全膝关节置换手术在术前的准备有限,作者提出基于计算机仿真和3D打印技术的数字化精准全膝置换方法,旨在通过充分的术前设计来提升置换效果。目的:利用计算机仿真和个性化手术导板建立数字化精准全膝关节置换方法,比较新方法和传统方法的临床效果。方法:回顾性分析97例全膝关节置换患者的临床资料,根据手术方法将患者分为2组,对照组(n=48)采取传统方式进行全膝关节置换手术,使用传统胶片模板;观察组(n=49)采用数字化精准全膝置换方法进行手术,使用计算机辅助技术选定假体尺寸型号。比较两组患者的手术时间、术中出血量、术前及术后美国特种外科医院膝关节评分以及股骨力线和膝关节面线夹角和胫骨角、髋膝踝角与标准角度的差值。结果与结论:(1)两组患者术前性别、年龄、体质量指数、美国特种外科医院膝关节评分,以及胫骨角、股骨力线和膝关节面线夹角、髋膝踝角与标准角度的差值相比差异均无显著性意义(P> 0.05);(2)与对照组比较,观察组手术时间缩短、出血量减少;两组术后3个月膝关节美国特种外科医院膝关节评分对比术前均显著升高(P> 0.05),且术后3个月观察组评分高于对照组(P> 0.05);(3)两组之间胫骨角、股骨力线和膝关节面线夹角、髋膝踝角与标准角度的差值相比差异均有显著性意义,观察组优于对照组(P <0.05);(4)观察组股骨假体预测准确率为94%,对照组为58%;胫骨假体预测准确率为96%,对照组为62%;(5)提示数字化精准全膝关节置换相较传统全膝关节置换的手术时间更短、出血量更少、术后膝关节功能评分和力线恢复更好,具有良好的短期临床效果。

基于α-shape的树冠LOD建模

以点云形式的树模型为输入,以3D Delaunay三角化为基础,选取最优α值并生成点云的最小连通α-shape;然后计算其距离场并进行滤波处理,以提取α-shape的光滑等距面;进一步采用Laplacian骨架提取的分割方法从等距面中分割出树干和树冠点云的包围体。最后以树冠包围体内点云的多分辨率α-shape为细节层次(LOD)模型用于非真实感VR场景。