Department of Neurosurgery, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany.
Trauma Research Centre Ulm, Institute of Orthopaedic Research and Biomechanics, Ulm University, Ulm, Germany.
Eur Spine J. 2021 Jun;30(6):1566-1573. doi: 10.1007/s00586-021-06848-7. Epub 2021 Apr 30.
Possible surgical therapies for odontoid fracture type IIb include odontoid screw osteosynthesis (OG) with preservation of mobility or dorsal C1/2 fusion with restriction of cervical rotation. In order to reduce material loosening in odontoid screw osteosynthesis in patients with low bone density, augmentation at the base of the axis using bone cement has been established as a suitable alternative. In this study, we compared cement-augmented OG and C1/2 fusion according to Harms (HG).
Body donor preparations of the 1st and 2nd cervical vertebrae were randomized in 2 groups (OG vs. HG). The range of motion (ROM) was determined in 3 principle motion plains. Subsequently, a cyclic loading test was performed. The decrease in height of the specimen and the double amplitude height were determined as absolute values as an indication of screw loosening. Afterward, the ROM was determined again and loosening of the screws was measured in a computed tomography.
A total of 16 were included. Two groups of 8 specimens (OG vs. HG) from patients with a median age of 80 (interquartile range (IQ) 73.5-85) years and a reduced bone density of 87.2 (IQ 71.2-104.5) mg/cc dipotassium hydrogen phosphate were examined for their biomechanical properties. Before and after exposure, the OG preparations were significantly more mobile. At the time of loading, the OG had similar loading properties to HG decrease in height of the specimen and the double amplitude height. Computed tomography revealed similar outcomes with regard to the screw loosening rate (62.5 vs. 87.5%, p = 0.586).
In patients with an odontoid fracture type IIb and reduced bone density, cement-augmented odontoid screw yielded similar properties in the loading tests compared to the HG. It may, therefore, be considered as a primary alternative to preserve cervical mobility in these patients.
对于 IIb 型齿状突骨折，可能的手术治疗方法包括保留活动度的齿状突螺钉内固定术（OG）或限制颈椎旋转的后路 C1/2 融合术。为了减少低骨密度患者齿状突螺钉内固定术中的材料松动，在枢椎基底处使用骨水泥进行增强已被确立为一种合适的替代方法。在这项研究中，我们根据 Harms （HG）标准比较了骨水泥增强的 OG 和 C1/2 融合术。
将 1 例和 2 例颈椎尸体标本随机分为 2 组（OG 组与 HG 组）。在 3 个主要运动平面上确定运动范围（ROM）。随后进行循环加载试验。以标本高度降低和双振幅高度作为螺钉松动的指示，确定绝对值。之后，再次确定 ROM，并在 CT 下测量螺钉松动情况。
共纳入 16 例患者。2 组 8 例（OG 组与 HG 组）患者的平均年龄为 80 岁（四分位距 73.5-85 岁），骨密度降低至 87.2mg/cc（二磷酸氢钾）。检测其生物力学性能。暴露前后，OG 组的标本活动度明显更大。在加载时，OG 与 HG 具有相似的加载特性，即标本高度降低和双振幅高度降低。CT 显示螺钉松动率相似（62.5%与 87.5%，p=0.586）。
对于 IIb 型齿状突骨折和低骨密度的患者，与 HG 相比，骨水泥增强的齿状突螺钉在加载试验中具有相似的性能。因此，它可能被视为这些患者保留颈椎活动度的主要替代方法。
