Xi Xin, Ling Zhi, Wang Cong, Gu Chunya, Zhan Xuqiang, Yu Haixin, Lu Siqi, Tsai Tsung-Yuan, Yu Yan, Cheng Liming
Department of Spine Surgery, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China.
Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration, Ministry of Education, Department of Spine Surgery, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China.
Front Bioeng Biotechnol. 2022 Aug 17;10:960063. doi: 10.3389/fbioe.2022.960063. eCollection 2022.
Traditional optical motion capture (OMC) with retroreflective markers is commonly used to measure joint kinematics but was also reported with unavoidable soft tissue artifacts (STAs) when quantifying the motion of the spine. Additionally, the patterns of the STA on the lumbar spine remain unclear. This study aimed to 1) quantify the STAs of the human lower back in three-dimensional directions during weight-bearing forward-backward bending and 2) determine the effects of the STAs on the calculated flexion angles between the upper and lower lumbar spines and adjacent vertebrae by comparing the skin marker (SM)- and virtual bone marker (VM)-based measurements. Six healthy volunteers were imaged using a biplanar radiographic system, and thirteen skin markers were mounted on every volunteer's lower back while performing weight-bearing forward-backward bending. The STAs in the anterior/posterior (AP), medial/lateral (ML), and proximal/distal (PD) directions were investigated. The flexion angles between the upper and lower lumbar segments and adjacent intervertebral segments (L2-L5) throughout the cycle were calculated. For all the participants, STAs continuously increased in the AP direction and exhibited a reciprocal trend in the PD direction. During flexion, the STA at the lower lumbar region (L4-L5: 13.5 ± 6.5 mm) was significantly higher than that at the upper lumbar (L1-L3: 4.0 ± 1.5 mm) in the PD direction ( < 0.01). During extension, the lower lumbar (L4-L5: 2.7 ± 0.7 mm) exhibited significantly less STAs than that exhibited by the upper lumbar region (L1-L3: 6.1 ± 3.3 mm) ( < 0.05). The STA at the spinous process was significantly lower than that on both sides in the AP direction ( < 0.05). The present results on STAs, based on dual fluoroscopic measurements in healthy adult subjects, presented an anatomical direction, marker location, and anatomic segment dependency, which might help describe and quantify STAs for the lumbar spine kinematics and thus help develop location- and direction-specific weighting factors for use in global optimization algorithms aimed at minimizing the effects of STAs on the calculation of lumbar joint kinematics in the future.
传统的带有反光标记的光学运动捕捉（OMC）通常用于测量关节运动学，但在量化脊柱运动时也会出现不可避免的软组织伪影（STA）。此外，腰椎STA的模式仍不清楚。本研究旨在：1）在负重前后弯曲过程中，在三维方向上量化人体下背部的STA；2）通过比较基于皮肤标记（SM）和虚拟骨标记（VM）的测量结果，确定STA对计算的上、下腰椎以及相邻椎体之间的屈曲角度的影响。使用双平面放射成像系统对六名健康志愿者进行成像，在每位志愿者进行负重前后弯曲时，在其下背部安装13个皮肤标记。研究了前后（AP）、内外（ML）和近端/远端（PD）方向的STA。计算了整个周期内上、下腰椎节段以及相邻椎间节段（L2-L5）之间的屈曲角度。对于所有参与者，STA在AP方向上持续增加，在PD方向上呈现相反趋势。在屈曲过程中，PD方向上腰椎下部区域（L4-L5：13.5±6.5毫米）的STA显著高于腰椎上部区域（L1-L3：4.0±1.5毫米）（<0.01）。在伸展过程中，腰椎下部区域（L4-L5：2.7±0.7毫米）的STA明显少于腰椎上部区域（L1-L3：6.1±3.3毫米）（<0.05）。棘突处的STA在AP方向上明显低于两侧（<0.05）。基于对健康成年受试者的双荧光透视测量得出的关于STA的当前结果，呈现了一种解剖学方向、标记位置和解剖节段依赖性，这可能有助于描述和量化腰椎运动学中的STA，从而有助于开发特定位置和方向的加权因子，以便在未来用于旨在最小化STA对腰椎关节运动学计算影响的全局优化算法。
