Minamide A, Tamaki T, Hashizume H, Yoshida M, Kawakami M, Hayashi N
Department of Orthopedic Surgery, Wakayama Medical College, Japan.
Spine (Phila Pa 1976). 1998 Apr 15;23(8):870-6. doi: 10.1097/00007632-199804150-00007.
Histologic examination was performed on autografted intervertebral disc materials of rabbit models, which were partially incised through a retroperitoneal approach at L1-L2 and grafted within the posterior epidural space at L4.
To evaluate whether the resorption process of the herniated intervertebral disc is influenced and controlled by treatments with medications.
Regarding resorption of herniated intervertebral discs, recent studies of magnetic resonance images and histologic investigations of surgically resected specimens in lumber disc herniation patients have been reported. It has been shown that inflammatory factors may play an important role in the mechanism of resorption of the herniated intervertebral disc. However, little is known about the origin of newly formed vessels and inflammatory cells detected in herniated disc specimens from patients. In this study, The resorption process of disc material grafted into the epidural space was observed in a rabbit model.
Thirty-six adult rabbits were used. The L1-L2 intervertebral disc was partially incised through a retroperitoneal approach. The harvested disc material, which contains the nucleus pulposus and the anulus fibrosus were placed into the posterior epidural space at L4 of the same rabbit. The animals were divided into control, and steroid groups. The control group received no treatment after surgery. In the lipopolysaccharide group, rabbits were injected 1 mg/kg into the peritoneum immediately and at 7 days after surgery. In the steroid group, rabbits were injected with 1 mg/kg betamethasone into the epidural space daily from 1 to 7 days after surgery. Rabbits of each group were killed for histologic examination at 1, 2, 4, and 8 weeks after surgery.
At 1 and 2 weeks after surgery, inflammatory cells and newly formed vessels were more frequently observed in the lipopolysaccharide group than in the control and steroid groups. At 4 weeks after surgery, derangement and loosening of collagen fibers were also observed in the lipopolysaccharide group. At 8 weeks after surgery, fragmentation and partial disappearance of matrix were observed in the control and lipopolysaccharide groups. Most of the intervertebral discs were replaced by fibrous tissues in the lipopolysaccharide group. However, the matrix of the intervertebral disc almost remained.
Autologous intervertebral disc material grafted into the epidural space was penetrated by newly formed vessels produced from the epidural fat tissue and resolved as the result of inflammatory reaction. Lipopolysaccharide accelerated the replacement of grafted intervertebral disc by fibrous tissue, which suggests the resorption of the disc in the epidural space of the rabbit, whereas high-dose steroid suppressed the replacement.
对兔模型的自体椎间盘材料进行组织学检查，通过腹膜后入路在L1 - L2处部分切开椎间盘，并将其移植到L4的硬脊膜后间隙内。
评估药物治疗是否会影响和控制突出椎间盘的吸收过程。
关于突出椎间盘的吸收，已有关于腰椎间盘突出症患者磁共振成像的最新研究以及手术切除标本的组织学研究报道。研究表明，炎症因子可能在突出椎间盘的吸收机制中起重要作用。然而，对于患者突出椎间盘标本中检测到的新生血管和炎症细胞的来源知之甚少。在本研究中，在兔模型中观察了移植到硬脊膜后间隙的椎间盘材料的吸收过程。
使用36只成年兔。通过腹膜后入路部分切开L1 - L2椎间盘。将收获的包含髓核和纤维环的椎间盘材料置于同一只兔的L4硬脊膜后间隙。动物分为对照组和类固醇组。对照组术后不进行治疗。在脂多糖组中，兔在术后立即及术后7天腹腔注射1mg/kg脂多糖。在类固醇组中，兔在术后1至7天每天向硬脊膜后间隙注射1mg/kg倍他米松。每组兔在术后1、2、4和8周处死进行组织学检查。
术后1周和2周，脂多糖组比对照组和类固醇组更频繁地观察到炎症细胞和新生血管。术后4周，脂多糖组还观察到胶原纤维排列紊乱和松散。术后8周，对照组和脂多糖组观察到基质破碎和部分消失。脂多糖组中大多数椎间盘被纤维组织替代。然而，椎间盘的基质几乎保留。
移植到硬脊膜后间隙的自体椎间盘材料被硬脊膜外脂肪组织产生的新生血管穿透，并因炎症反应而溶解。脂多糖加速了移植椎间盘被纤维组织替代，这表明兔硬脊膜后间隙中椎间盘的吸收，而高剂量类固醇抑制了这种替代。
