Regeneration of a Spinal Ligament after Total Lumbar Disk Arthroplasty in Primates

Abstract

Total disk arthroplasty (TDA) is a new procedure that replaces the intervertebral disk space with an artificial motion segment and necessitates the resection of the anterior longitudinal ligament (ALL). We assessed whether a collagen-based graft made from porcine small-intestine submucosa (SIS) can be used as a regenerative scaffold to restore the function and structure of the ALL in the lumbar spine. A total of 10 mature male baboons underwent TDA at L5–L6 using one of two treatments: (1) TDA only (n = 5) or (2) TDA combined with SIS (n = 5). Six months postoperatively, mock revision surgery was performed to assess tissue adhesions followed by non-destructive multidirectional flexibility testing of the spinal segment. The vertebral segments were then processed for histology. The tissue adhesion score was 2.8 ± 0.8 in the TDA only group and 1.8 ± 1.4 in the TDA-SIS group (p = 0.2). Segmental range of motion and the length of the neutral zone were similar in both groups. Histology showed that the SIS scaffold led to an organized ligamentous structure with a significantly (p = 0.027) higher thickness (2.18 ± 0.25 mm) compared to the connective tissue structure in the TDA-only group (1.66 ± 0.33 mm). We concluded that using a SIS bioscaffold after TDA did not lead to increased great vessel adhesion while its use facilitated the formation of highly organized ligamentous tissues. However, the SIS- induced and newly formed ligamentous tissue anterior to the spinal segment did not lead to a measurable limitation of spinal extension.

Biomechanical analysis of the camelid cervical intervertebral disc

“…Also, while similarities may be drawn between the gravity load on the human spine and the muscle load on the quadruped spine, there remains much to learn about the effects of the differences in the biomechanical loading environment. Ethical concerns pre-emptively reduce our willingness to promote testing on primates [7] , [8] , [11] , [12] , [13] , [14] .…”