Abstract: Abstract Objective: To determine the histologic changes of the cervical intervertebral discs and surrounding tissues after nucleoplasty. Methods：The experimental study was performed in 10 sheep, and each sheep was treated with nucleoplasty in C4-5 and C5-6. Chronic histologic changes were observed by light microscopy at 0，2，4 weeks after cervical nucleoplasty. Results：Two sheep were euthanized immediately after treatment, and the oval-shaped cavities were observed on the macroscopic view in the nucleus pulposus. The cavities measured between 1.5 mm to 2.3mm in long axis and between 0.4mm to 0.7mm in short. 2 weeks after nuleoplasty, the cavities were shortened. 4 weeks after nucleoplasty, the cavities was replaced by nucleus pulposus and fibrous tissues. Condusion: Nucleoplasty did not result in thermal damage or other significant damaging effects to the adjacent annulus and end plate, the cavities produced by nucleoplasty were rehabilitated finally. Nucleoplasty is a safe procedure to cervical spine.

Key words: Nucleoplasty, Intervertebral disc, Cervical vertebrae, Animals, Histology