Chaiyamongkol Weera, Kritsaneephaiboon Apipop, Bintachitt Piyawat, Suwannaphisit Sitthiphong, Tangtrakulwanich Boonsin
Department of Orthopaedic Surgery and Physical Medicine, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand.
Asian Spine J. 2018 Dec;12(6):967-972. doi: 10.31616/asj.2018.12.6.967. Epub 2018 Oct 16.
Biomechanical study.
To investigate the relative stiffness of a new posterior pelvic fixation for unstable vertical fractures of the sacrum.
The reported operative fixation techniques for vertical sacral fractures include iliosacral screw, sacral bar fixations, transiliac plating, and local plate osteosynthesis. Clinical as well as biomechanical studies have demonstrated that these conventional techniques are insufficient to stabilize the vertically unstable sacral fractures.
To simulate a vertically unstable fractured sacrum, 12 synthetic pelvic models were prepared. In each model, a 5-mm gap was created through the left transforaminal zone (Denis zone II). The pubic symphysis was completely separated and then stabilized using a 3.5-mm reconstruction plate. Four each of the unstable pelvic models were then fixed with two iliosacral screws, a tension band plate, or a transiliac fixation plus one iliosacral screw. The left hemipelvis of these specimens was docked to a rigid base plate and loaded on an S1 endplate by using the Zwick Roell z010 material testing machine. Then, the vertical displacement and coronal tilt of the right hemipelves and the applied force were measured.
The transiliac fixation plus one iliosacral screw constructions could withstand a force at 5 mm of vertical displacement greater than the two iliosacral screw constructions (p=0.012) and the tension band plate constructions (p=0.003). The tension band plate constructions could withstand a force at 5° of coronal tilt less than the two iliosacral screw constructions (p=0.027) and the transiliac fixation plus one iliosacral screw constructions (p=0.049).
This study proposes the use of transiliac fixation in addition to an iliosacral screw to stabilize vertically unstable sacral fractures. Our biomechanical data demonstrated the superiority of adding transiliac fixation to withstand vertical displacement forces.
生物力学研究。
研究一种用于不稳定型骶骨垂直骨折的新型骨盆后路固定术的相对刚度。
报道的用于垂直型骶骨骨折的手术固定技术包括髂骶螺钉、骶骨棒固定、经髂钢板固定和局部钢板骨合成术。临床及生物力学研究均表明，这些传统技术不足以稳定垂直不稳定型骶骨骨折。
为模拟垂直不稳定型骨折骶骨，制备了12个合成骨盆模型。在每个模型中，通过左侧经椎间孔区域（Denis II区）制造一个5毫米的间隙。耻骨联合完全分离，然后用一块3.5毫米的重建钢板进行固定。然后，将四个不稳定骨盆模型分别用两枚髂骶螺钉、一块张力带钢板或经髂固定加一枚髂骶螺钉进行固定。这些标本的左半骨盆对接至一块刚性基板，并使用Zwick Roell z010材料试验机在S1终板上加载。然后，测量右半骨盆的垂直位移和冠状面倾斜度以及施加的力。
经髂固定加一枚髂骶螺钉结构在垂直位移5毫米时能够承受的力大于两枚髂骶螺钉结构（p = 0.012）和张力带钢板结构（p = 0.003）。张力带钢板结构在冠状面倾斜5°时能够承受的力小于两枚髂骶螺钉结构（p = 0.027）和经髂固定加一枚髂骶螺钉结构（p = 0.049）。
本研究提出除髂骶螺钉外，使用经髂固定来稳定垂直不稳定型骶骨骨折。我们的生物力学数据证明了增加经髂固定以承受垂直位移力的优越性。
