Department of Orthopaedic Surgery, Loma Linda University School of Medicine,Loma Linda, CA 92354-2871, USA.
Spine J. 2011 Jul;11(7):e15-9. doi: 10.1016/j.spinee.2011.06.002. Epub 2011 Jun 24.
A randomized controlled multicenter investigational device exemption clinical trial comparing the total facet arthroplasty system (TFAS) (Archus Orthopedics, Redmond, WA, USA) with posterior fusion was discontinued because of financial reasons. To our knowledge, no clinical outcomes or complications have yet been presented for the TFAS, and no device-related complications have been reported for any other lumbar facet replacement system.
To report and discuss two cases of stem fracture after total facet replacement in the lumbar spine.
Case report and literature review.
A 55-year-old man with a body mass index (BMI) of 40 underwent total facet replacement at L4-L5 for Grade 1 spondylolisthesis with stenosis. After 9 months of pain relief, he experienced gradually increasing pain and radiographs showed a broken stem. A 60-year-old woman with a BMI of 31 underwent total facet replacement at L4-L5 for Grade 1 spondylolisthesis with stenosis. She experienced stem fracture 27 months postoperatively.
Visual analog scale for pain, Oswestry Disability Index for function, and computed tomography and X-ray for imaging.
After TFAS stem breakage, both patients underwent interbody fusion through a transpsoas approach and have done well over 24- and 12-month follow-up periods, respectively.
These are the first cases of stem fracture reported after total facet replacement in the lumbar spine. Biomechanics of TFAS stem breakage may be similar to those of pedicle screw breakage, including fatigue and three-point bending stress. Further biomechanical studies and failure analyses however are needed for adequate understanding to improve the biomechanics of dynamic pedicle-based devices.
一项比较全关节突切除术(total facet arthroplasty system, TFAS)（美国华盛顿州雷德蒙德市 Archus Orthopedics 公司）与后路融合的随机对照多中心研究性设备豁免临床试验因财务原因而中断。据我们所知，目前尚未报告 TFAS 的临床结果或并发症，也没有任何其他腰椎小关节置换系统报告与该设备相关的并发症。
报告并讨论两例腰椎全关节突置换术后椎弓根骨折病例。
病例报告和文献复习。
1 例 55 岁男性，BMI 为 40，因 1 级伴狭窄的脊椎滑脱行 L4-L5 全关节突置换术。缓解疼痛 9 个月后，他逐渐出现疼痛加重，影像学显示椎弓根断裂。1 例 60 岁女性，BMI 为 31，因 1 级伴狭窄的脊椎滑脱行 L4-L5 全关节突置换术。术后 27 个月发生椎弓根骨折。
疼痛的视觉模拟评分、功能的 Oswestry 残疾指数以及影像学的 CT 和 X 线。
在 TFAS 椎弓根断裂后，两名患者均通过前路经椎间孔腰椎椎体间融合术（transpsoas approach）进行治疗，分别在 24 个月和 12 个月的随访期后恢复良好。
这是首次报道腰椎全关节突置换术后椎弓根骨折病例。TFAS 椎弓根断裂的生物力学机制可能与椎弓根螺钉断裂相似，包括疲劳和三点弯曲应力。然而，需要进一步的生物力学研究和失效分析，以充分了解，从而改善基于动力椎弓根的装置的生物力学性能。
