The transpedicular surgical approach for the development of intervertebral disc targeting regenerative strategies in an ovine model

Abstract

Purpose: To investigate the suitability of the transpedicular approach (TPA) in a sheep model of IVD regenerative strategies METHODS: 24 IVD from four sheep were used. TPA and biopsies of the Nucleus pulposus (NP) were performed in 18 IVD (6 IVD control). Seven discographies were performed to assess the feasibility of injecting contrast agent. MRI, micro-CT scan, and histological analyses were performed and the accuracy of the TPA was evaluated. The effects on the vertebra and endplates were analyzed.

Results: 83% of our biopsies or injections were located in the NP. Osseous fragments in IVD were observed in 50%. We observed two cases (11%) of rostral endplate fracture and five cases (27%) of breaching of the cortical pedicle and encroachment into the spinal canal. Two cases of perivertebral venous embolism and two of backflow through the canal of the TPA inside the vertebra were noted. Significant damage occurred to the bone structure of the vertebra and to the rostral endplate on which the IVD had been inserted.

Conclusions: TPA induces damage to the endplates, and it may lead to neurological impairment and leakage of injected materials into the systemic circulation. These adverse effects must be fully considered before proceeding with TPA for IVD regenerative strategies.

Keywords: Degeneration; Intervertebral disc; Regenerative medicine; Transpedicular approach.