腰椎后路术后骶棘肌损伤的实验研究

The experimental study on multifidus injury after posterior lumbar spine surgery

目的观察腰椎后入路手术时骶棘肌不同程度的外科创伤与其组织形态学之间的相关性。方法将成年新西兰大白兔20只随机均匀地分为五组:A组(对照组),B组(假手术组),C组(低张力组),D组(高张力短时间组),E组(高张力长时间组)。每组分别于术中骶棘肌牵开前、术后即刻、术后2d、1周、2周、1月、2月取压力感应片下的深层骶棘肌肌肉,分别送石蜡、冰冻及透射电镜检查。结果各后路手术实验组随骶棘肌剥离、牵拉和持续时间的逐渐加大而呈现逐渐加剧的病理改变,总的结果是呈现变性、坏死和修复反应的顺序演变。在损伤早期,主要呈现不同程度的横纹肌细胞间水肿、炎细胞浸润和核内移;严重者可出现腊样变性及液化性坏死,腊样变性肌细胞。从术后第1周起,肌组织的坏死越来越明显,并逐渐向修复反应过渡,可出现片状的小群状肌萎缩或肌纤维同型化;后期最主要的是纤维组织大量增生并替代大片萎缩的肌纤维。电镜的病理改变与光镜结果相一致,后期可见大量的胶原纤维和成纤维细胞增生,有大量脂滴聚集现象。结论不同程度的骶棘肌剥离、牵拉能造成不同程度的骶棘肌损伤,其牵拉力和持续时间的大小与组织学结果相平行,电镜与光镜组织学结果是相一致的;多种损伤机制(压迫、缺血、代谢紊乱、失神经支配)

Objective To observe the association between the surgical trau ma of multifidus and its histomorphology after the posterior lumbar surgery. Me thods Twenty New Zealand adult rabbits were randomized into five groups of the s ame size: control, pseudo-operation, lower tension, higher tension+shorter dur ation and higher tension+longer duration groups. The deep multifidus histologic sections under the pressure retractor and their ultrastructures were examined u nder transmission electron microscope at various time-points (before operation and instantly after operation, as well as two days, one week, two weeks, one mon th and two months after operation). Results In the experimental posterior operat ions, the pathological extent of muscle fiber showed a parallelism with the magn itude of the pressure load and retraction time. At a very early postoperative ti me,the intercellular edema, inflammatory cell infiltration and internal nuclei were observed to increase with the presence of target fiber or ragged red fiber. At the mean time, the presence of liquefactive necrosis or opaque fiber within the whole trans-sectional areas was found in severe cases. Regeneration of musc le fibers and neuromuscular junction began by 1 week postoperatively and the pre sence of fiber atrophy and fiber type grouping were detected. The late pathohist ological examinations showed severe fibrosis and muscle fibers almost replaced b y connective tissues or scar. The ultrastructure examinations showed a paralleli sm with histological examinations. Namely, the myofibril dissolution, mitochondr ial fragmentation and swollen sarcoplasmic reticulum were present. At later time s, severe connective tissues and fibroblast proliferation or numerous aggregatio n of lipoid emerged. Conclusions The various extents of multifidus encroachment and severity of pathohistology show a parallelism with the magnitude of the pres sure load and retraction time, and with the ultrastuctural results and histologi cal examinations. Several injury mechanisms (pressure, ischemia, metabolic unbal ance and denervation) involve the traumatized muscle fiber at the posterior app roach operation.