Gullbrand Sarah E, Kiapour Ali, Barrett Caitlin, Fainor Matthew, Orozco Brianna S, Hilliard Rachel, Mauck Robert L, Hast Michael W, Schaer Thomas P, Smith Harvey E
Department of Orthopaedic Surgery, McKay Orthopaedic Research Laboratory, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Translational Musculoskeletal Research Center, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, USA.
Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
Acta Biomater. 2025 Jan 15;192:128-139. doi: 10.1016/j.actbio.2024.12.014. Epub 2024 Dec 9.
Intervertebral disc degeneration is commonly associated with back and neck pain, and standard surgical treatments do not restore spine function. Replacement of the degenerative disc with a living, tissue-engineered construct has the potential to restore normal structure and function to the spine. Toward this goal, our group developed endplate-modified disc-like angle-ply structures (eDAPS) that recapitulate the native structure and function of the disc. While our initial large animal studies utilized rigid internal fixation of the eDAPS implanted level to ensure retention of the eDAPS, chronic immobilization does not restore full function and is detrimental to the spinal motion segment. The purpose of this study was to utilize a goat cervical disc replacement model coupled with finite element modeling of goat cervical motion segments to investigate the effects of remobilization (removal of fixation) on the eDAPS, the facet joints and the adjacent paraspinal muscle. Our results demonstrated that chronic immobilization caused notable degeneration of the facet joints and paraspinal muscles adjacent to eDAPS implants. Remobilization improved eDAPS composition and integration and mitigated, but did not fully reverse, facet joint osteoarthritis and paraspinal muscle atrophy and fibrosis. Finite element modeling revealed that these changes were likely due to reduced range of motion and reduced facet loading, highlighting the importance of maintaining normal spine biomechanical function with any tissue engineered disc replacement. STATEMENT OF SIGNIFICANCE: Back and neck pain are ubiquitous in modern society, and the gold standard surgical treatment of spinal fusion limits patient function. This study advances our understanding of the response of the spinal motion segment to tissue engineered disc replacement with provisional fixation in a large animal model, further advancing the clinical translation of this technology.
椎间盘退变通常与颈肩痛相关，而标准的手术治疗无法恢复脊柱功能。用有生命的组织工程构建体替换退变椎间盘有可能恢复脊柱的正常结构和功能。为实现这一目标，我们团队开发了终板改良的盘状角向铺层结构（eDAPS），该结构可重现椎间盘的天然结构和功能。虽然我们最初的大型动物研究利用了对植入eDAPS节段的刚性内固定来确保eDAPS的保留，但长期固定并不能恢复全部功能，且对脊柱运动节段有害。本研究的目的是利用山羊颈椎间盘置换模型并结合山羊颈椎运动节段的有限元建模，来研究解除固定（去除固定装置）对eDAPS、小关节和相邻椎旁肌的影响。我们的结果表明，长期固定导致eDAPS植入物附近的小关节和椎旁肌显著退变。解除固定改善了eDAPS的组成和整合，并减轻了但未完全逆转小关节骨关节炎以及椎旁肌萎缩和纤维化。有限元建模显示，这些变化可能是由于运动范围减小和小关节负荷降低所致，突出了在任何组织工程椎间盘置换中维持正常脊柱生物力学功能的重要性。重要性声明：颈肩痛在现代社会普遍存在，脊柱融合的金标准手术治疗会限制患者功能。本研究增进了我们对大型动物模型中脊柱运动节段对临时固定的组织工程椎间盘置换的反应的理解，进一步推动了该技术的临床转化。
