Neuroscience Institute, Allegheny General Hospital, Pittsburgh, PA, USA.
Department of Neurosurgery, University of California Irvine, Irvine, CA, USA.
J Orthop Surg Res. 2020 Oct 22;15(1):489. doi: 10.1186/s13018-020-02013-w.
A number of minimally invasive sacroiliac (SI) joint fusion solutions for placing implants exist, with reduced post-operative pain and improved outcomes compared to open procedures. The objective of this study was to compare two MIS SI joint fusion approaches that place implants directly across the joint by comparing the ilium and sacrum bone characteristics and SI joint separation along the implant trajectories.
Nine cadaveric specimens (n = 9) were CT scanned and the left and right ilium and sacrum were segmented. The bone density, bone volume fraction, and SI joint gap distance were calculated along lateral and posterolateral trajectories and compared using analysis of variance between the two orientations.
Iliac bone density, indicated by the mean Hounsfield Unit, was significantly greater for each lateral trajectory compared to posterolateral. The volume of cortical bone in the ilium was greater for the middle lateral trajectory compared to all others and for the top and bottom lateral trajectories compared to both posterolateral trajectories. Cortical density was greater in the ilium for all lateral trajectories compared to posterolateral. The bone fraction was significantly greater in all lateral trajectories compared to posterolateral in the ilium. No differences in cortical volume, cortical density, or cancellous density were found between trajectories in the sacrum. The ilium was significantly greater in density compared with the sacrum when compared irrespective of trajectory (p < 0.001). The posterolateral trajectories had a significantly larger SI joint gap than the lateral trajectories (p < 0.001).
Use of the lateral approach for minimally invasive SI fusion allows the implant to interact with bone across a significantly smaller joint space. This interaction with increased cortical bone volume and density may afford better fixation with a lower risk of pull-out or implant loosening when compared to the posterolateral approach.
有许多微创的骶髂（SI）关节融合技术可用于植入物的放置，与开放手术相比，术后疼痛减轻，效果改善。本研究的目的是通过比较两种直接穿过关节放置植入物的微创 SI 关节融合方法，比较沿植入物轨迹的髂骨和骶骨特征以及 SI 关节分离，来比较两种 MIS SI 关节融合方法。
对 9 具尸体标本（n = 9）进行 CT 扫描，并对左右髂骨和骶骨进行分割。沿外侧和后外侧轨迹计算骨密度、骨体积分数和 SI 关节间隙距离，并通过两种方向的方差分析进行比较。
髂骨的骨密度，以平均 Hounsfield 单位表示，每个外侧轨迹都明显大于后外侧轨迹。髂骨中间外侧轨迹的皮质骨体积明显大于其他所有轨迹，而顶部和底部外侧轨迹则明显大于两个后外侧轨迹。所有外侧轨迹的皮质骨密度均大于后外侧。髂骨的骨分数在所有外侧轨迹中都明显大于后外侧。在骶骨中，各轨迹间的皮质骨体积、皮质骨密度或松质骨密度均无差异。髂骨的密度明显大于骶骨，无论轨迹如何（p < 0.001）。后外侧轨迹的 SI 关节间隙明显大于外侧轨迹（p < 0.001）。
微创 SI 融合的外侧入路允许植入物在明显较小的关节间隙内与骨骼相互作用。与后外侧入路相比，这种与增加的皮质骨体积和密度的相互作用可能提供更好的固定，降低拔出或植入物松动的风险。
