躯干侧方压伤肌挛缩致脊柱侧凸的病因探索

Experimental Investigation of Scoliosis Caused by Compressing Muscle Contracture at Truncal Concave Side in Pup

采用２１～２８日龄杂种犬１８只，体重０．８～１．２ｋｇ，随机分为手术组、强制性侧卧位组及对照组（ｎ＝６）。手术组在硫喷妥钠（３０ｍｇ／ｋｇ）腹腔内注射麻醉下，将躯干一侧下６肋间区的背阔肌、胸大肌及腹外斜肌等重叠缝合，使其短缩２．５～３．０ｃｍ，术后脊柱即成侧凸畸形，凹向手术侧，凸向非手术侧，术后２个月缝线松动，肌肉重叠消失，脊柱侧凸的角度逐渐消失而恢复正常。强制性侧卧组：采用四条腿固定架将犬的四条腿固定，强制侧卧在沙袋上，保持同一侧卧位４～８周，侧卧受力区的肌肉组织缺血、变性、粘连、挛缩，脊柱逐渐形成固定性侧凸，凹向卧侧，凸向非卧侧，ｃｏｂｂ角１７～３３°，对照组：实行自由体位，观察时间与实验组相同，６只均无脊柱侧凸畸形。结果说明较长时间的强制性一侧卧位可使幼犬发生肌挛缩性脊柱侧凸。其脊柱侧凸的特点及躯干受力区肌肉组织细胞学的改变与人类特发性脊柱侧凸症极其相似。提示：特发性脊柱侧凸的病因与新生儿期实行强制性侧卧位可能有密切关系。

Eighteen healthy hybrid pups weighing 0.8 to 1.2kg at the age of 21 to 28 days old were divided randomly into three groups as follows: ① Operative group: under general anaesthesia, the broadest muscle of back, greater Pectoral muscle and external oblique muscle of abdomen were subjected to overlapping suture at one truncal side and shortened by 2.5 to 3cm. The spine became scoliosis after operation and the concave side was at operation side. Two months after operation, the suture was loose and the scoliosis was disappeared gradually. ② Forced lateral position group: the dogs were fixed and made it lateral position at the sand bag for 4 to 8 weeks. The muscle of compressed region were suffered from myoischeimia, degeneration, adhesion and cicatricial contracture. The spine became fixed scoliosis and convex to the other side(cobb's 17°33°)·and ③ Control group: the dogs were freely lived during the experiment. All the dogs of this group were without scoliosis. The results showed that the forced lateral position for certain time can make the pups to muscle contracture scoliosis. The characteristics of scoliosis and the cytological changes of muscle in compression region were the same as human idiopathic scoliosis. It indicated that the aetiology of idopathic scoliosis has a close relation with forced lateral positon during infantile period.