Proceedings of the NASS 20th Annual Meeting / The Spine Journal 5 (2005) 1S–189S 133S Table 1 Segmental kinematic changes (%) with respect to intact NZ NZ ROM ROM Stiff Stiff Load Nucl Impl Nucl Impl Nucl Impl Comp 34 4 73* -8* -11* -2* AR 24 8 13* 2* -4 -3 F/E 84* 2* 12* 4* 39* -8* LB 62* 12* 3 2 13* 0* AR=axial rotation; Comp=compression; F/E=flexion/extension; Impl= implanted device; LB=lateral bending; Nucl=nucleotomy; NZ=neutral zone; ROM=range of motion. * Significant differences between conditions. OUTCOME MEASURES: NA. METHODS: Twelve human lumbar functional spine units (FSUs; age: 546 yrs) were nondestructively tested in compression (1200N), axial rotation (5.5 Nm), flexion/extension (7.5 Nm), and lateral bending (7.5 Nm). Moments were combined with 500N compression. Each FSU was tested in three conditions: Intact, after nuclectomy and with an implanted device. Neutral zone (NZ), range of motion (ROM) and stiffness were obtained from load displacement curves and statistically compared between conditions using a repeated measures analysis of variance. RESULTS: Compared with the intact state, nuclectomy significantly in- creased the NZ during all load modalities (Table 1). Furthermore, nuclec- tomy increased ROM during all load modalities except lateral bending. Finally, nuclectomy increased stiffness only during flexion/extension and lateral bending. Implantation of the study device restored all kinematic parameters to near intact values. CONCLUSIONS: The results of this study demonstrate that the study device is able to restore the segmental flexibility lost after a nucleotomy while still preserving segmental level biomechanics. The results of this study suggest that the DASCOR device is biomechanically well suited to act as a long-term replacement for the degenerative nucleus pulposus. DISCLOSURES: FDA device/drug: DASCOR Disc Arthroplasty System. Status: Investigational/not approved. CONFLICT OF INTEREST: Author (NO) Grant Research Support: Disc Dynamics, Inc.; Authors (AT, BB) Other: Employee of Disc Dynamics, Inc.; Author (HY) Stockholder: Disc Dynamics, Inc.; Author (HY) Board Member: Disc Dynamics, Inc. doi: 10.1016/j.spinee.2005.05.264 P50. Effect of disc height restoration and subsidence on outcome after total disc replacement minimum 2-year follow-up David Musante, MD 1 , Jack Zigler, MD 2 , Barton Sachs, MD 2 , Ralph Rashbaum, MD 2 , Gregory Elders, MD 2 , Donna Ohnmeiss, PhD 3 ; 1 Plano, TX, USA; 2 Texas Back Institute, Plano, TX, USA; 3 Texas Back Institute Research Foundation, Plano, TX, USA BACKGROUND CONTEXT: Total disc replacement has become a surgi- cal option for the treatment of symptomatic lumbar degenerative disc disease (DDD). Little prospective data exists on which intraoperative and postoperative variables are important for improved outcomes. No study to our knowledge has evaluated the effect of intraoperative disc height restora- tion and postoperative subsidence on radiological and clinical outcome measures. PURPOSE: The purpose of this study was to evaluate the effect of intraop- erative disc height restoration and postoperative subsidence on radiological and clinical outcome measures after total disc replacement. STUDY DESIGN/SETTING: Data for the study were collected at a spine specialty center participating in the FDA regulated trial evaluating the ProDisc. Clinical data were collected prospectively and radiographs were measured by surgeons not involved with the surgeries. PATIENT SAMPLE: Patients were included in the study if they had undergone total disc replacement for the treatment of single-level symptom- atic disc degeneration unresponsive to nonoperative care. Only the 29 patients with a minimum 2-year follow-up were included. OUTCOME MEASURES: Clinical outcome measures included pre- and postoperative visual analog scale assessing pain and the Oswestry Disability Index questionnaire. Radiographic measures included disc height and seg- mental range of motion (ROM). METHODS: All patients had undergone total disc replacement at a single level from L3/4 to L5/S1 as part of the FDA IDE study. All data were gathered according to the protocol preoperatively and at 6 weeks, 3, 6, 12, 18 and 24 months. Disc height restoration was calculated from anterior and posterior vertebral disc heights on preoperative and 6-week postoperative lateral radiographs. Subsidence was calculated from disc heights on 3-month to 24-month lateral radiographs. Segmental ROM was calculated as the differ- ence in Cobb angles between flexion and extension lateral radiographs. Significant changes in disc height, subsidence and ROM were determined by student t test. Pearson correlations were determined among these vari- ables and the clinical outcomes measures. RESULTS: Disc height increased significantly from preoperative values to the 6 week follow-up (47% anteriorly, 33% posteriorly; p.001). Disc height decreased by 24-months but was still significantly increased over preoperative values (p.01). Postoperative ROM values demonstrated a trend toward greater values than preoperatively and reached statistical significance at the 24 month follow-up (preoperative 3.14.7 degrees vs. postoperative 6.14.4 degrees; p=.004). Postoperative ROM was significantly improved compared with the preoperative value (p.05). There was no correlation at any time point between intraoperative disc height restoration, postoperative subsidence, ROM, VAS, and Oswestry scores. CONCLUSIONS: Total disc replacement is associated with significant disc height increase, postoperative subsidence and preservation of operative level ROM. However, there is no correlation between these two variables nor is there any correlation between these variables and postoperative range of motion or clinical outcome. DISCLOSURES: No disclosures. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2005.05.265 P51. Induction of annular repair by the implantation of cultured annulus cell with PGA scaffold Jae-Taek Hong 1 , Sang Won Lee 1 , Il-Woo Lee, MD 2* , Byung-Chul Son 1 , Jae-Hoon Sung 1 , In-Soo Kim 1 , Moon Chan Kim 3 ; 1 Catholic University of Korea, St. Vincent Hospital, Suwon, Kyong-Gi, South Korea; 2 Catholic University of Korea, Daejon St. Marys’ Hospital, Daejun, South Korea; 3 Catholic University of Korea, Kang Nam St Marys’ Hospital, Seoul, South Korea BACKGROUND CONTEXT: The intervertebral disc is histologically classified as fibrocartilage, it is one of the areas with the poorest blood flow in the human body, and its regeneration capacity is very low. Thus, in cases with the removal of the intervertebral disc as a therapeutic mode for the intervertebtal disc herniation, or cases with degenerative interver- tebral disc, it is difficult to anticipate the regeneration of the intervertebral disc. This study was performed by applying cell culture and tissue engi- neering methods to evaluate the regeneration capacity of implanted disc cells after the transplant of cultured annulus cells to the resected area of invertebral disc. PURPOSE: This study assessed whether the transplant of cultured cartilage cells that is currently applied in clinics primarily for degenerative arthritis can be applied to the degenerative intervertebral disc. STUDY DESIGN/SETTING: We investigated the in vivo response of allografted annulus cells with PGA scaffold into the inbred Fisher rat intervertebral disc. PATIENT SAMPLE: Fourteen inbred Fisher rats.