Effect of Nd:YAG laser on experimental disc degeneration. Part II. Histological and MR imaging findings.

The potential advantages of percutaneous procedures over traditional discectomy are multiple, but the use of laser energy to ablate disc tissue appears entirely empirical. To date, no experimental study exists investigating the results of laser on degenerated intervertebral disc. The present study was therefore undertaken to determine the histological and radiological changes induced by neodymium-yttrium-aluminum-garnet (Nd:YAG) laser on such disc tissue. It was shown that the vaporization of disc tissue was caused by Nd:YAG laser in early period, but this was gradually replaced by cartilaginous fibrous tissue at 60 days after laser irradiation as a result of the proliferation of cartilaginous cells and fibrous tissues. Accordingly the magnetic resonance (MR) imaging index histogram moved to the left in the early period, but it moved to the right again at 60 days after laser irradiation. In view of these data, we conclude that the use of laser in degenerated disc disease does not represent an effective treatment as an alternative to conventional surgical methods.