1. Maturation of the Posterolateral Spinal Fusion and Its Effect on Load-Sharing of Spinal Instrumentation. An In Vivo Sheep Model* by MASAHIRO KANAYAMA, BRYAN W. CUNNINGHAM, JAMES C. WEIS, LARRY M. PARKER, KIYOSHI KANEDA, and PAUL C. McAFEE J Bone Joint Surg Am Volume 79(11):1710-20 November 1, 1997 ©1997 by The Journal of Bone and Joint Surgery, Inc.

2. Fig. 1 Photograph made after the operative procedure. MASAHIRO KANAYAMA et al. J Bone Joint Surg Am 1997;79:1710-20 ©1997 by The Journal of Bone and Joint Surgery, Inc.

3. Fig. 2 Photograph made after insertion of rods with uniaxial strain-gauges to measure the strain on the hardware. MASAHIRO KANAYAMA et al. J Bone Joint Surg Am 1997;79:1710-20 ©1997 by The Journal of Bone and Joint Surgery, Inc.

4. Fig. 3 Graph of the time-related change in the torsional stiffness of the posterolateral fusion mass (PLF) and the instrumented control. MASAHIRO KANAYAMA et al. J Bone Joint Surg Am 1997;79:1710-20 ©1997 by The Journal of Bone and Joint Surgery, Inc.

5. Fig. 4-A Graphs of the time-related changes in axial (Fig. 4-A) and bending (Fig. 4-B) stresses on the rod during left lateral bending. MASAHIRO KANAYAMA et al. J Bone Joint Surg Am 1997;79:1710-20 ©1997 by The Journal of Bone and Joint Surgery, Inc.

6. Fig. 4-B Graphs of the time-related changes in axial (Fig. 4-A) and bending (Fig. 4-B) stresses on the rod during left lateral bending. MASAHIRO KANAYAMA et al. J Bone Joint Surg Am 1997;79:1710-20 ©1997 by The Journal of Bone and Joint Surgery, Inc.

7. Figs. 5-A through 5-D: Anteroposterior plain radiographs of the posterolateral arthrodesis segments that were removed after the sheep were killed. MASAHIRO KANAYAMA et al. J Bone Joint Surg Am 1997;79:1710-20 ©1997 by The Journal of Bone and Joint Surgery, Inc.

8. Fig. 5-B: Eight weeks postoperatively, one observer graded this fusion as B (possibly solid), but the other two graded it as C (probably not solid) and D. MASAHIRO KANAYAMA et al. J Bone Joint Surg Am 1997;79:1710-20 ©1997 by The Journal of Bone and Joint Surgery, Inc.

9. Fig. 5-C: Twelve weeks postoperatively, all three observers graded19 this fusion as A (definitely solid). MASAHIRO KANAYAMA et al. J Bone Joint Surg Am 1997;79:1710-20 ©1997 by The Journal of Bone and Joint Surgery, Inc.

10. Fig. 5-D: Sixteen weeks postoperatively, all three observers graded this fusion as A. MASAHIRO KANAYAMA et al. J Bone Joint Surg Am 1997;79:1710-20 ©1997 by The Journal of Bone and Joint Surgery, Inc.

11. Fig. 6-A Computerized tomography scans of the posterolateral arthrodesis segments at four (Fig. 6-A), eight (Fig. 6-B), twelve (Fig. 6-C), and sixteen weeks (Fig. 6-D). MASAHIRO KANAYAMA et al. J Bone Joint Surg Am 1997;79:1710-20 ©1997 by The Journal of Bone and Joint Surgery, Inc.

12. Fig. 6-B Computerized tomography scans of the posterolateral arthrodesis segments at four (Fig. 6-A), eight (Fig. 6-B), twelve (Fig. 6-C), and sixteen weeks (Fig. 6-D). MASAHIRO KANAYAMA et al. J Bone Joint Surg Am 1997;79:1710-20 ©1997 by The Journal of Bone and Joint Surgery, Inc.

13. Fig. 6-C Computerized tomography scans of the posterolateral arthrodesis segments at four (Fig. 6-A), eight (Fig. 6-B), twelve (Fig. 6-C), and sixteen weeks (Fig. 6-D). MASAHIRO KANAYAMA et al. J Bone Joint Surg Am 1997;79:1710-20 ©1997 by The Journal of Bone and Joint Surgery, Inc.

14. Fig. 6-D Computerized tomography scans of the posterolateral arthrodesis segments at four (Fig. 6-A), eight (Fig. 6-B), twelve (Fig. 6-C), and sixteen weeks (Fig. 6-D). MASAHIRO KANAYAMA et al. J Bone Joint Surg Am 1997;79:1710-20 ©1997 by The Journal of Bone and Joint Surgery, Inc.

15. Figs. 7-A through 7-D: Histological parasagittal section of the posterolateral fusion mass (Villanueva osteochrome bone stain, x 1). MASAHIRO KANAYAMA et al. J Bone Joint Surg Am 1997;79:1710-20 ©1997 by The Journal of Bone and Joint Surgery, Inc.

16. Fig. 7-B: At eight weeks, woven bone was predominant within the fusion mass. MASAHIRO KANAYAMA et al. J Bone Joint Surg Am 1997;79:1710-20 ©1997 by The Journal of Bone and Joint Surgery, Inc.

17. Fig. 7-C: At twelve weeks, a partly trabeculated osseous fusion mass bridged the transverse processes but was still immature. MASAHIRO KANAYAMA et al. J Bone Joint Surg Am 1997;79:1710-20 ©1997 by The Journal of Bone and Joint Surgery, Inc.

18. Fig. 7-D: At sixteen weeks, the entire fusion-mass area was composed of trabeculated bone. MASAHIRO KANAYAMA et al. J Bone Joint Surg Am 1997;79:1710-20 ©1997 by The Journal of Bone and Joint Surgery, Inc.

19. Fig. 8 Graph showing the results of the histomorphometric analysis of the posterolateral spinal fusion mass. MASAHIRO KANAYAMA et al. J Bone Joint Surg Am 1997;79:1710-20 ©1997 by The Journal of Bone and Joint Surgery, Inc.