Braun John T, Hoffman Michael, Akyuz Ephraim, Ogilvie James W, Brodke Darrel S, Bachus Kent N
Department of Orthopaedics, University of Utah, School of Medicine, Salt Lake City, UT 84108, USA.
Spine (Phila Pa 1976). 2006 May 20;31(12):1314-20. doi: 10.1097/01.brs.0000218662.78165.b1.
Wedging of apical spinal segments was measured during creation and correction of an experimental scoliosis in a goat model.
To create and correct apical vertebral wedge deformities in a progressive experimental scoliosis model by purely mechanical means.
The creation and correction of vertebral wedge deformities has been previously described in a rat tail model using external fixation.
Experimental scoliosis was created in 14 goats using a posterior asymmetric tether with convex rib resection and concave rib tethering. After a period of up to 13 weeks, all tethers were removed and goats were randomized into treated (n = 8) and untreated (n = 6) groups. Treated goats underwent anterior thoracic stapling with four shape memory alloy staples along the convexity of the maximal curvature. Goats were followed for an additional 7 to 13 weeks during treatment. Serial radiographs were used to document progression or correction of the maximal scoliotic deformity as well as to measure the wedging of the apical spinal segment (two adjacent vertebrae and the intervening disc).
During the tethering period, all goats achieved a progressive, structural, lordoscoliotic curve of significant magnitude (mean: 61 degrees, range: 49 to 73 degrees). Wedging of the apical spinal segment measured 11.1 degrees at the beginning and 22.4 degrees at the end of the tethering period. The increase in apical spinal segment wedging of +11.3 degrees (10.7 degrees vertebral/0.6-degree disc) was significant (P = 0.001). During the treatment period, the scoliosis in the stapled goats measured 56.8 degrees at the beginning and 43.4 degrees at the end for an average correction of -13.4 degrees (range: 0 to-22 degrees) (P = 0.001), whereas the untreated goats measured 67.0 degrees at the beginning and 59.8 degrees at the end for an average correction of -7.2 degrees (range: +7 to -21 degrees) (P = 0.19). Additionally, wedging of the apical spinal segment in the stapled goats measured 22.5 degrees at the beginning and 20.3 degrees at the end for an average correction of -2.2 degrees (-0.6 degrees vertebral/-1.6-degree disc); wedging of the apical vertebral segment in the untreated goats measured 22.3 degrees at the beginning and 25.8 degrees at the end of the treatment period for an average progression of +3.5 degrees (3.5 degrees vertebral/0.0-degree disc). The difference in apical spinal segment correction versus progression in the stapled (-2.2 degrees) versus control (+3.5 degrees) goats was significant (P < 0.05).
This study demonstrates the ability to create wedge deformities at the apex of an experimental scoliosis in a large animal model and to control the progression of these deformities using anterior thoracic staples.
在山羊模型中建立并矫正实验性脊柱侧凸的过程中，测量脊柱顶端节段的楔形变。
通过单纯机械方法在进展性实验性脊柱侧凸模型中建立并矫正顶端椎体楔形变。
此前曾在大鼠尾部模型中利用外固定来建立和矫正椎体楔形变。
对14只山羊采用后路不对称牵张，切除凸侧肋骨并固定凹侧肋骨，建立实验性脊柱侧凸。经过长达13周的一段时间后，拆除所有牵张装置，将山羊随机分为治疗组（n = 8）和未治疗组（n = 6）。治疗组山羊沿最大弯曲凸侧用4枚形状记忆合金钉进行前路胸椎固定。在治疗期间对山羊再随访7至13周。采用系列X线片记录最大脊柱侧凸畸形的进展或矫正情况，并测量脊柱顶端节段（相邻两个椎体及其间的椎间盘）的楔形变。
在牵张期，所有山羊均形成了显著程度的进展性、结构性、脊柱前凸侧弯畸形（平均：61度，范围：49至73度）。脊柱顶端节段的楔形变在牵张期开始时为11.1度，结束时为22.4度。脊柱顶端节段楔形变增加了11.3度（椎体10.7度/椎间盘0.6度），差异有统计学意义（P = 0.001）。在治疗期，固定钉固定的山羊脊柱侧凸在开始时为56.8度，结束时为43.4度，平均矫正-13.4度（范围：0至-22度）（P = 0.001），而未治疗的山羊开始时为67.0度，结束时为59.8度，平均矫正-7.2度（范围：+7至-21度）（P = 0.19）。此外，固定钉固定的山羊脊柱顶端节段楔形变在开始时为22.5度，结束时为20.3度，平均矫正-2.2度（椎体-0.6度/椎间盘-1.6度）；未治疗山羊脊柱顶端椎体楔形变在治疗期开始时为22.3度，结束时为25.8度，平均进展+3.5度（椎体3.5度/椎间盘0.0度）。固定钉固定组（-２.2度）与对照组（+3.5度）山羊在脊柱顶端节段矫正与进展方面的差异有统计学意义（P < 0.05）。
本研究证明了在大型动物模型中，能够在实验性脊柱侧凸的顶端形成楔形变，并使用前路胸椎固定钉来控制这些畸形的进展。
