Hydroxylapatite-coated Diapason screws: first clinical report.

We report our preliminary experience with 27 patients who underwent surgery for posterior spinal arthrodesis using the hydroxylapatite-coated Diapason screws. Each of the patients was considered to have a condition that was mechanically risky from the surgical standpoint. The results were good for patients with lytic spondylolisthesis and were excellent for patients with osteoporosis, but were generally less successful for patients requiring "long lever arm" fixations and those with degenerative scoliosis.