Orthopaedic Biomechanics Laboratory, Advanced Regenerative Tissue Engineering Centre, Sunnybrook Research Institute, Toronto, Ontario, Canada.
Spine (Phila Pa 1976). 2012 Sep 15;37(20):E1296-303. doi: 10.1097/BRS.0b013e318266ecea.
An in vitro biomechanical and imaging study generated from an in vivo porcine model of early stage degenerative disc disease was used to evaluate mechanical property restoration, comparing 2 minimally invasive injection techniques.
To evaluate the ability of an injectable hydrogel to restore the mechanical properties of spinal motion segments with early stage disc degeneration, comparing 2 minimally invasive injection techniques.
Treatment of early-stage disc degeneration may benefit from a combination of tissue engineering and minimally invasive therapeutic approaches. A recently developed hydrogel, thiol-modified hyaluronan elastin-like polypeptide (TMHA/EP) composite, has demonstrated potential as an injectable nucleus replacement.
From a total of thirteen 35-kg Yorkshire boars, early-stage lumbar disc degeneration was introduced into 10 pigs via injection of chondroitinase ABC. After degeneration, 8 pigs received TMHA/EP augmentation; 1 disc via direct needle injection and a second using a modified kyphoplasty approach. High-resolution magnetic resonance images were acquired of the excised spinal motion segments, followed by biomechanical testing in axial compression, flexion-extension, lateral bending, and torsion.
The degenerate control motion segments were generally less stiff and more flexible than healthy controls. The injection of TMHA/EP into the degenerated nucleus produced similar mechanical stiffness to healthy controls. The direct-injected discs showed a dispersive pattern of TMHA/EP within the nucleus, whereas the modified kyphoplasty method yielded a bolus of hydrogel. Yet, mechanical behavior was comparable considering the 2 minimally invasive augmentation techniques.
The TMHA/EP composite can restore initial mechanical behavior in early-stage disc degeneration. Although both augmentation methods yielded mechanical properties comparable with healthy controls, direct injection represents a simpler technique, uses a smaller-gauge needle, does not introduce air into the disc, and yields a dispersive pattern that may be beneficial for future delivery of cells or growth factors.
本研究采用体内猪早期退行性椎间盘模型，体外生物力学和影像学研究评估了两种微创注射技术，比较了两种微创注射技术对早期退行性椎间盘疾病的机械性能恢复能力。
评估一种可注射水凝胶对早期椎间盘退变脊柱运动节段机械性能的恢复能力，比较两种微创注射技术。
早期椎间盘退变的治疗可能受益于组织工程和微创治疗方法的结合。最近开发的一种水凝胶，巯基修饰透明质酸弹性蛋白样多肽（TMHA/EP）复合材料，已被证明是一种有潜力的可注射核替代物。
共 13 头 35 公斤约克郡猪，通过注射软骨素酶 ABC 引入早期腰椎间盘退变。退变后，8 头猪接受 TMHA/EP 增强；1 个椎间盘直接针注射，另一个采用改良的后凸成形术。对切除的脊柱运动节段进行高分辨率磁共振成像，然后进行轴向压缩、屈伸、侧屈和扭转生物力学测试。
退变对照组运动节段通常比健康对照组刚度较小，柔韧性较大。向退变核内注射 TMHA/EP 可产生与健康对照组相似的机械刚度。直接注射组的 TMHA/EP 在核内呈弥散分布，而改良后凸成形术组则呈水凝胶团块。然而，考虑到两种微创增强技术，力学行为是可以比较的。
TMHA/EP 复合材料可恢复早期椎间盘退变的初始力学行为。虽然两种增强方法都产生了与健康对照组相当的力学性能，但直接注射技术更简单，使用较小的针，不会向椎间盘内引入空气，并且呈弥散分布，这可能有利于未来细胞或生长因子的输送。
