关键词: 组织构建, 骨组织工程, 脊柱, 腰椎, 椎间盘, 椎间植骨, 同种异体骨, 内固定

Abstract:

BACKGROUND: In treatment of lumbar diseases, lumbar fusion therapy fails in 20% of cases and may lead to a series of complications such as pain, intervertebral space collapse, and delayed kyphosis deformity.
OBJECTIVE: To observe the effect of nucleus pulposus on interbody fusion after removing the anterior column disc of rabbit lumbar vertebra.
METHODS: A total of 36 healthy Japanese white rabbits were randomly and equally divided into three groups, with 12 rabbits in each group. (1) Group of anterior longitudinal ligament+bone grafting: The L3 intercalated disc were well exposed and anterior longitudinal ligament was stripped, obtaining a space to L3 intercalated disc, then the iliac bone was implanted. (2) Group of excising anterior 1/3 disc+bone grafting: After the anterior 1/3 disc tissue was excised, the iliac bone was implanted and sutured as Group of anterior longitudinal ligament+bone grafting. (3) Group of excising anterior 1/3 disc+fixation: After the anterior 1/3 disc tissue was excised, the iliac bone was implanted and the anterior column fixation was performed.
RESULTS AND CONCLUSION: Biomechanical testing showed that, at 12 weeks, the verticality tensile force in the group of anterior longitudinal ligament+bone grafting was obviously higher than other two groups, and have better fusion rate and could bear stronger force. Lateral position lumbar radiography showed that, the bone graft was absorbed and no new bone grew into the intervertebral space in the group of excising anterior 1/3 disc+bone grafting at 12 weeks; the formation of osseous bridge was found in the group of excising anterior 1/3 disc+fixation; complete bony fusion was found in the group of anterior longitudinal ligament+bone grafting. Histological examinations showed that, at 12 weeks, no bone tissue formed in the group of excising anterior 1/3 disc+bone grafting; a small amount of bone trabecula and osteocytes were observed in the group of excising anterior 1/3 disc+fixation; a great quantity of newborn bone trabecula and osteocytes, remodeling lamellar bone and canalis haversi structure were observed in the group of anterior longitudinal ligament+bone grafting. The stability of anterior column has notable effect on interbody fusion, after the anterior column disc is destroyed, the free nucleus pulposus may affect spinal fusion, so restoring the stability of the anterior column may promote interbody fusion, but still cannot get solid spinal fusion.

Key words:  lumbar vertebrae, intervertebral disk, bone transplantation, internal fixators