1. Prevalence of Heterotopic Ossification Following Total Disc Replacement by P. Justin Tortolani, Bryan W. Cunningham, MMech Eng, Paul C. McAfee, Gwen A. Holsapple, and Karen A. Adams J Bone Joint Surg Am Volume 89(1):82-88 January 1, 2007 ©2007 by The Journal of Bone and Joint Surgery, Inc.

2. P. Justin Tortolani et al. J Bone Joint Surg Am 2007;89:82- 88 ©2007 by The Journal of Bone and Joint Surgery, Inc.

3. P. Justin Tortolani et al. J Bone Joint Surg Am 2007;89:82- 88 ©2007 by The Journal of Bone and Joint Surgery, Inc.

4. Anteroposterior radiograph demonstrating Class-II heterotopic ossification between the vertebral end plates (arrows) in a patient twenty-four months after implantation of a CHARITÉ Artificial Disc at the L4-L5 level. P. Justin Tortolani et al. J Bone Joint Surg Am 2007;89:82- 88 ©2007 by The Journal of Bone and Joint Surgery, Inc.

5. P. Justin Tortolani et al. J Bone Joint Surg Am 2007;89:82- 88 ©2007 by The Journal of Bone and Joint Surgery, Inc.

6. P. Justin Tortolani et al. J Bone Joint Surg Am 2007;89:82- 88 ©2007 by The Journal of Bone and Joint Surgery, Inc.

7. Preoperative and postoperative Oswestry Disability Index (ODI) scores for patients with and without heterotopic ossification (HO). P. Justin Tortolani et al. J Bone Joint Surg Am 2007;89:82- 88 ©2007 by The Journal of Bone and Joint Surgery, Inc.

8. Preoperative and postoperative visual analog scores (VAS) for patients with and without heterotopic ossification (HO). P. Justin Tortolani et al. J Bone Joint Surg Am 2007;89:82- 88 ©2007 by The Journal of Bone and Joint Surgery, Inc.

9. Computed tomography scan made four years postoperatively through the L4-L5 disc space of a patient who was seen to have Class-I heterotopic ossification on plain radiographs. P. Justin Tortolani et al. J Bone Joint Surg Am 2007;89:82- 88 ©2007 by The Journal of Bone and Joint Surgery, Inc.