Szivek John A, Roberto Rolando F, Margolis David S
Orthopaedic Research Lab, Department of Orthopaedic Surgery, University of Arizona, Tucson, Arizona 85724, USA.
J Biomed Mater Res B Appl Biomater. 2005 Nov;75(2):243-50. doi: 10.1002/jbm.b.30262.
Currently, spine fusion is determined using radiography and clinical evaluation. There are discrepancies between radiographic evidence and direct measurements of fusion, such as operative exploration and biomechanical or histological measurements. In order to facilitate the rapid return of patients to normal activities, a monitoring technique to accurately detect fusion in vivo and to prevent overload during the postoperative period would be useful. The objectives of this study were to develop an implantable monitoring system consisting of CPC-coated strain gauges and a radio transmitter to detect the onset of fusion and measure strain during postsurgical activities. A patient underwent anterior release and fusion, followed by posterior instrumentation and fusion with segmental spinal instrumentation. Four strain gauges were placed during surgery. One was attached to the left-side rod and one to each of the lamina at T9, T10, and T11. An externally powered implanted radio transmitter attached to the gauges was placed in a subcutaneous pouch. Strains were monitored weekly and tabulated during various activities for 7 months. Peak strains during twisting and bending were tabulated to detect the onset of fusion. Strains were also recorded during activities such as climbing off an examination table, rising from a chair, and climbing stairs. Strains collected from the left rod indicated that, immediately postoperatively, it was loaded at acceptable levels. The largest and most consistent strain changes measured from the lamina were recorded during twisting.
目前，脊柱融合是通过影像学检查和临床评估来确定的。影像学证据与融合的直接测量结果之间存在差异，如手术探查以及生物力学或组织学测量。为了促进患者快速恢复正常活动，一种能够在体内准确检测融合并防止术后过载的监测技术将很有用。本研究的目的是开发一种由磷酸钙骨水泥涂层应变片和无线电发射器组成的植入式监测系统，以检测融合的开始并测量术后活动期间的应变。一名患者接受了前路松解融合术，随后进行后路器械固定和节段性脊柱器械融合术。手术过程中放置了四个应变片。一个附着在左侧棒上，另外三个分别附着在T9、T10和T11的椎板上。一个由外部供电的植入式无线电发射器连接到应变片上，并放置在皮下袋中。每周监测应变，并在7个月的各种活动中制成表格。记录扭转和弯曲过程中的峰值应变以检测融合的开始。在诸如从检查台上下来、从椅子上起身和爬楼梯等活动中也记录了应变。从左侧棒收集的应变表明，术后立即，其负荷处于可接受水平。从椎板测量到的最大且最一致的应变变化是在扭转过程中记录的。
