[Experience with prosthetic disc nucleus device in Mexico. Final report of a 4-year follow-up]

Discal hernia is generally treated by discectomies that are mutilating and cause instability and low back pain in 50% of the patients. Partial arthroplasty is used in an attempt to avoid degeneration after a discectomy.

Nineteen patients from the INR (National Institute of Rehabilitation) were selected with extruded discal hernia. All inclusion criteria were met, with a minimal follow-up of 4 years. Evolution was evaluated with the Oswestry scale (OS) and x-ray studies. Statistical analysis was done with Student's t-test.

Sixteen men and three women were included in the study, with an average age of 35.4 years. OS before surgery was 57.37% and improved to 22% (p < 0.001). The results obtained in the Prolo scale 4 years later were for the economy scale, p < 0.001 (Wilcoxon Z = 3.87) and for the functional scale, p < 0.001 (Wilcoxon Z = -3.94). The intervertebral space height (IS) before surgery was 6 and 8 mm, and 4 years later, in 12 patients it remained between 8 and 10 mm. The prosthesis had variations according to its initial placement in seven patients, and in all there was subsidence. In two cases migration surpassed the limits of the vertebral body without clinical repercussion. None of the patients required re-operation.

Prosthetic disc nucleus device improved clinical conditions and x-rays of the patients using Oswestry, Prolo and intersomatic space height enhancement after 4 years of follow-up in 12/19 patients.