Park Soo-An, Ordway Nathaniel R, Fayyazi Amir H, Fredrickson Bruce E, Yuan Hansen A
Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan, Seoul, South Korea.
J Spinal Disord Tech. 2009 Dec;22(8):602-9. doi: 10.1097/BSD.0b013e318198791e.
Prospective clinical study.
To compare the amount of segmental motion in the sagittal plane after lumbar total disc arthroplasty (TDA) measured by using the Cobb technique, quantitative motion analysis (QMA), and radiostereometric analysis (RSA).
The aim of TDA is preservation of motion and therefore essential to properly quantify the motion. Clinically, segmental motion is measured by using the Cobb technique, which involves either the endplates or the implant as radiographic landmarks. This technique has been reported to have large intraobserver and interobserver variability. QMA and RSA are in vivo techniques that can measure the segmental motion with accuracy, but have not been compared with each other or compared with the Cobb technique in the literature.
Ten patients (6 males and 4 females, 47 + or - 7 y) with lumbar disc degeneration were surgically treated with ProDisc-L (Synthes Inc). Intraoperatively, tantalum beads were inserted into each vertebra and patients were followed postoperatively at 1 month, 1 year, and 2 years. At each follow-up time-point, biplanar flexion/extension radiographs were obtained and sagittal range of motion (ROM) of the index level was calculated by using the RSA technique. Clinical flexion/extension radiographs were also obtained and the sagittal ROM at the same level was calculated by using a modified Cobb technique. The clinical films were additionally analyzed by Medical Metrics for sagittal ROM using QMA. The results of the 3 measurement techniques were statistically analyzed and compared in pairwise fashion.
A significant difference (P = 0.02) was observed between the Cobb technique (5.9 + or - 4.9) and RSA (3.5 + or - 2.4). A trend (P = 0.069) was also seen between QMA (5.7 + or - 4.7) and RSA. On paired-samples correlation, a significantly high correlation was seen between Cobb technique and QMA (r = 0.868, P < 0.001). A larger variability was seen when using the Cobb technique or QMA in comparison to the RSA.
Sagittal ROM after TDA was similar between QMA and digital Cobb technique. A larger variability was seen between these techniques and RSA.
前瞻性临床研究。
比较采用Cobb技术、定量运动分析（QMA）和放射立体测量分析（RSA）测量腰椎全椎间盘置换术（TDA）后矢状面节段运动的量。
TDA的目的是保留运动，因此准确量化运动至关重要。临床上，节段运动采用Cobb技术测量，该技术将终板或植入物作为放射学标志。据报道，该技术在观察者内和观察者间存在较大变异性。QMA和RSA是可在体内准确测量节段运动的技术，但在文献中尚未相互比较或与Cobb技术进行比较。
10例腰椎间盘退变患者（6例男性，4例女性，47±7岁）接受ProDisc-L（Synthes公司）手术治疗。术中，将钽珠植入每个椎体，术后1个月、1年和2年对患者进行随访。在每个随访时间点，获取双平面屈伸位X线片，并使用RSA技术计算索引节段的矢状面活动度（ROM）。还获取临床屈伸位X线片，并使用改良的Cobb技术计算同一节段的矢状面ROM。临床影像还通过Medical Metrics使用QMA进行矢状面ROM分析。对这三种测量技术的结果进行统计学分析，并进行两两比较。
Cobb技术（5.9±4.9）与RSA（3.5±2.4）之间观察到显著差异（P = 0.02）。QMA（5.7±4.7）与RSA之间也出现了一种趋势（P = 0.069）。在配对样本相关性分析中，Cobb技术与QMA之间存在显著的高相关性（r = 0.868，P < 0.001）。与RSA相比，使用Cobb技术或QMA时变异性更大。
TDA后矢状面ROM在QMA和数字Cobb技术之间相似。这些技术与RSA之间的变异性更大。
