椎间盘源性下腰痛的发病机制

The pathogenesis of discogenic low back pain

目的 探讨椎间盘源性下腰痛的发病机制。方法 收集腰椎后路切除的 17例椎间盘源性下腰痛患者的 19个经腰椎间盘造影术证实的疼痛腰椎间盘 ;同时收集 12个在MRIT2 加权像上信号强度明显减弱、无腰痛症状的生理老化椎间盘和 10个正常对照椎间盘 ,行组织学检查和P物质、神经丝蛋白和血管活性肠肽的免疫组织化学染色检查。结果 椎间盘源性下腰痛患者的疼痛椎间盘在组织学上的显著特征表现为 ,一条从髓核至纤维环外层的血管化肉芽组织条带区 ,其间伴有 1个或多个裂隙 ;肉芽组织条带区与椎间盘造影术后CT上显示的纤维环裂隙一致 ,肉芽组织之外的纤维环结构基本正常。生理老化椎间盘和正常对照椎间盘表现为与年龄相关的改变。免疫组织化学染色显示 ,疼痛椎间盘中P物质、神经丝蛋白和血管活性肠肽 3种神经肽阳性神经纤维分布数量和比例 ,较正常对照椎间盘和生理老化椎间盘明显增多 ;神经纤维主要沿伴有裂隙的肉芽组织条带区分布 ;疼痛椎间盘髓核中可见P物质和神经丝蛋白的阳性神经纤维分布。结论 椎间盘后方神经分布广泛的肉芽组织条带区是椎间盘造影术疼痛和椎间盘源性下腰痛的起源部位。肉芽组织条带可能起源于椎间盘的创伤修复过程。

Objective To study the pathogenesis of the pain of discography and the discogenic low back pain. Methods 19 specimens of lumbar intervertebral discs from 17 patients with discogenic low back pain during posterior lumbar interbody fusion,and 12 physiologically aging discs and 10 normal control discs were collected to investigate the morphologic features and innervation containing neuropeptides substance P (SP),neural filament (NF),and vasoactive-intestinal peptide (VIP). Results The distinct morphologic characteristic of the disc from the patient with discogenic low back pain was the formation of the strip zone of vascularized granulation tissue from the nucleus pulposus to the outer part of the annulus fibrosus in which there was one or several fissures.The structure of annulus fibrosus beyond the strip zone of granulation tissue was basically normal.The structures of the aging discs and the control discs showed the age-related changes.The innervation of SP,NF and VIP immunoreactive nerve fibers in the painful discs was more extensive compared with the aging discs and the control discs.The nerve ingrowth deep into annulus fibrosus and nucleus pulposus was observed mainly along the strip zone of granulation tissue in the painful discs. Conclusions Findings indicate that the strip zone of granulation tissue with extensive innervation in the posterior part of the painful disc is the original site of the pain of discography and the discogenic low back pain.The strip zone of granulation tissue mighe originate from the injury and subsequent reparation of the margin of annulus fibrosus.The difference of the aging disc and painful disc which can not be differed each other on MRI is the formation of the strip zone of granulation tissue along tear histologically in posterior part of the painful disc.