title: [Experience with prosthetic disc nucleus device in Mexico. Final report of a 4-year follow-up].
abstract: BACKGROUND
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Servicio de Cirugía de Columna Vertebral, Instituto Nacional de Rehabilitación/Ortopedia, México, D.F., Mexico.
authors.forename: Luis Miguel
authors.initials: LM
authors.lastname: Rosales-Olivares
authors.forename: Ariel
authors.initials: A
authors.lastname: Pérez-Víquez
authors.forename: Víctor
authors.initials: V
authors.lastname: Miramontes-Martínez
authors.forename: Armando
authors.initials: A
authors.lastname: Alpízar-Aguirre
authors.forename: Alejandro Antonio
authors.initials: AA
authors.lastname: Reyes-Sánchez
mesh_terms: D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000601:surgery*; D008297:Male; D008800:Mexico; D008875:Middle Aged; D019736:Prostheses and Implants; D011474:Prosthesis Design; D013997:Time Factors; D055815:Young Adult