Mohar Janez, Valič Matej, Podovšovnik Eva, Mihalič Rene
Department of Spine Surgery, Valdoltra Orthopedic Hospital, Jadranska C. 31, 6280, Ankaran, Europe, Slovenia.
Chair of Orthopedics, Medical Faculty, University of Ljubljana, Ljubljana, Slovenia.
Eur Spine J. 2022 Dec;31(12):3544-3550. doi: 10.1007/s00586-022-07427-0. Epub 2022 Oct 29.
Pedicle screw (PS) placement in thoracic scoliotic deformities can be challenging due to altered vertebral anatomy; malposition can result in severe functional disability or inferior construct stability. Three-dimensional (3D) printed patient-specific guides (PSGs) have been recently used to supplement other PS placement techniques. We conducted a single-center, retrospective observational study to assess the accuracy of PS placement using PSGs in a consecutive case series of pediatric and adult patients with thoracic scoliosis.
We analyzed the data of patients with thoracic scoliosis who underwent PS placement using 3D-printed PSG as a vertebral cannulation aid between June 2013 and July 2018. PS positions were determined via Gertzbein-Robbins (GR) and Heary classifications on computed tomography images. We determined the concordance of actual and preoperatively planned PS positions and defined the technique learning curve using a receiver-operating characteristic (ROC) curve.
We performed 362 thoracic PS placement procedures in 39 consecutive patients. We classified 352 (97.2%), 2 (0.6%), and 8 (2.2%) screws as GR grades 0 (optimal placement), I, and II, respectively. The average instrumented PS entry point offsets on the X- and Y-axes were both 0.8 mm, and the average differences in trajectory between the planned and the actual screw placements on the oblique sagittal and oblique transverse planes were 2.0° and 2.4°, respectively. The learning process was ongoing until the first 12 PSs were placed.
The accuracy of PS placement using patient-specific 3D templates in our case series exceeds the accuracies of established thoracic PS placement techniques.
由于椎体解剖结构改变，在胸椎脊柱侧凸畸形中置入椎弓根螺钉（PS）具有挑战性；位置不当可能导致严重的功能障碍或内固定稳定性欠佳。三维（3D）打印的患者特异性导向器（PSG）最近已被用于辅助其他PS置入技术。我们进行了一项单中心回顾性观察研究，以评估在一系列连续的小儿和成人胸椎脊柱侧凸患者中使用PSG进行PS置入的准确性。
我们分析了2013年6月至2018年7月期间使用3D打印的PSG作为椎体插管辅助工具进行PS置入的胸椎脊柱侧凸患者的数据。通过计算机断层扫描图像上的Gertzbein-Robbins（GR）和Heary分类来确定PS的位置。我们确定了实际和术前计划的PS位置的一致性，并使用受试者操作特征（ROC）曲线定义了技术学习曲线。
我们对39例连续患者进行了362例胸椎PS置入手术。我们将352枚（97.2%）、2枚（0.6%）和8枚（2.2%）螺钉分别分类为GR 0级（最佳置入）、I级和II级。PS置入点在X轴和Y轴上的平均偏移均为0.8 mm，在斜矢状面和斜横断面上计划和实际螺钉置入轨迹之间的平均差异分别为2.0°和2.4°。在放置前12枚PS之前，学习过程一直在进行。
在我们的病例系列中，使用患者特异性3D模板进行PS置入的准确性超过了既定的胸椎PS置入技术的准确性。
