Fusion rate and biomechanical stiffness of hydroxylapatite versus autogenous bone grafts for anterior discectomy. An in vivo animal study. Spine (Phila Pa 1976) 1994 Nov 15;19(22):2524-8
Date
11/15/1994Pubmed ID
7855676DOI
10.1097/00007632-199411001-00006Scopus ID
2-s2.0-0028032371 (requires institutional sign-in at Scopus site) 55 CitationsAbstract
STUDY DESIGN: The fusion rate and biomechanical stiffness were evaluated for 56 goat spinal units from 14 animals that had anterior discectomies and grafting procedures completed using hydroxylapatite and autogenous bone and survived for 6, 12, and 24 week healing times.
OBJECTIVES: Harvested spinal units underwent radiographic imaging to assess fusion, biomechanical testing in axial compression, flexion, extension, lateral bending, and axial rotation to assess strength, and histological analysis. The above results were compared for the two procedures and the different healing times.
SUMMARY OF BACKGROUND DATA: Because of some of the complications associated with the use of autogenous iliac crest bone graft in spine fusions, there has been considerable interest in the use of calcium phosphate ceramics as a possible substitute for a grafting material. One of the attractive features of calcium phosphate ceramics is the resulting strong bond that is formed with the host bone unlike other inert compounds.
METHODS: Surgeries were done at four sites on each animal with two in the cervical spine and two in the lumbar spine. Radiography was done during the survival time and postsacrifice. Biomechanical testing was done on the day of sacrifice under physiological loads. Both hard tissue sections and decalcified sections were histologically evaluated.
RESULTS: A 55% fusion rate for bone preparations and a 50% fusion rate for the hydroxylapatite (HA) units was found for the 12 and 24 week preparations. The HA preparations were better at maintaining disc space height. The biomechanical analysis revealed significantly higher stiffness values for fused preparations than for nonfused samples under extension, lateral bending, and axial rotation. Fused units demonstrated no statistical difference in biomechanical stiffness between HA versus autogenous bone units for any mode of loading.
CONCLUSIONS: Our results indicate that these dense, nonresorbable hydroxylapatite blocks perform as well as autogenous bone for anterior spinal fusions in this animal model. The use of this hydroxylapatite material in anterior spine fusions may have some clinical validity.
Author List
Pintar FA, Maiman DJ, Hollowell JP, Yoganandan N, Droese KW, Reinartz JM, Cuddy BAuthors
Frank A. Pintar PhD Chair, Professor in the Biomedical Engineering department at Medical College of WisconsinNarayan Yoganandan PhD Professor in the Neurosurgery department at Medical College of Wisconsin
MESH terms used to index this publication - Major topics in bold
AnimalsBiomechanical Phenomena
Bone Transplantation
Cervical Vertebrae
Diskectomy
Durapatite
Goats
Ilium
Lumbar Vertebrae
Prostheses and Implants
Spinal Fusion
Stress, Mechanical
Transplantation, Autologous