Department of Orthopaedics and Traumatology, Hacettepe University, Ankara, Turkey.
Spine (Phila Pa 1976). 2010 Apr 1;35(7):730-3. doi: 10.1097/BRS.0b013e3181bcc3a3.
Experimental study.
The aim of this study is to evaluate the vertebral body growth under distraction forces in immature pigs treated with growing rod (GR) technique.
Distraction forces applied on growth plate of appendicular skeleton stimulate longitudinal growth. However, the effect of distraction forces on axial skeletal growth has not been fully investigated yet.
Twelve 10-week-old domestic pigs were used in this experimental model to simulate GR technique. Four of them were lost during postoperative period because of deep wound infection. Cranially T12-L1 and caudally L4-L5 vertebrae were instrumented by pedicle screws bilaterally, while L2 and L3 were skipped. Distraction between pedicle screws was applied at index surgery. The rods were then lengthened twice in a month interval. All subjects were evaluated with anteroposterior and lateral spinal radiograph before surgery, after surgery, and at the final follow-up. The vertebral body heights of distracted segments (HD = L2 and L3) and control segments (HC = T9, T10 and T11) were measured. Average vertebral body heights and the increase percentage in the vertebral body heights were compared among control segments and distracted segments.
The preoperative vertebral body height was similar in 2 groups (preHC: 10.81 mm, n = 19, preHD: 11.27 mm, n = 16, P > 0.05). At the final follow-up, the average vertebral body height in distraction group was significantly higher than the control group (postHC: 17.03 mm, postHD: 18.58 mm, P < 0.05). The increase percentage in vertebral body height was higher in distracted segments, but there was no statistically significant difference between the 2 groups.
The vertebral growth continues during GR instrumentation. Distraction forces might stimulate also apophyseal growth of axial skeleton.
实验研究。
本研究旨在评估使用生长棒（GR）技术治疗的未成熟猪在分离力下的椎体生长情况。
施加在附肢骨骼生长板上的分离力刺激纵向生长。然而，分离力对轴性骨骼生长的影响尚未得到充分研究。
本实验模型使用 12 只 10 周龄的家猪来模拟 GR 技术。其中 4 只由于术后深部伤口感染而在术后期间丢失。通过双侧椎弓根螺钉对 T12-L1 颅侧和 L4-L5 尾侧进行器械固定，同时跳过 L2 和 L3。在索引手术时施加椎弓根螺钉之间的分离。然后，在一个月的间隔内将棒两次延长。所有受试者在术前、术后和最终随访时均进行前后位和侧位脊柱 X 线摄影评估。测量分离节段（HD=L2 和 L3）和对照节段（HC=T9、T10 和 T11）的椎体高度。比较对照节段和分离节段的平均椎体高度和椎体高度的增加百分比。
两组术前椎体高度相似（preHC：10.81mm，n=19，preHD：11.27mm，n=16，P>0.05）。在最终随访时，分离组的平均椎体高度明显高于对照组（postHC：17.03mm，postHD：18.58mm，P<0.05）。分离节段的椎体高度增加百分比较高，但两组之间无统计学差异。
GR 器械置入过程中椎体生长继续。分离力也可能刺激轴向骨骼的骺生长。
