TY - JOUR
T1 - Role of biomechanics in intervertebral disc degeneration and regenerative therapies
T2 - What needs repairing in the disc and what are promising biomaterials for its repair?
AU - Iatridis, James C.
AU - Nicoll, Steven B.
AU - Michalek, Arthur J.
AU - Walter, Benjamin A.
AU - Gupta, Michelle S.
N1 - Funding Information:
This work was made possible by funding from the National Institutes of Health ( R01AR051146 , R01AR057397 , and HL007944 ) and AO Foundation (JCI and SBN). We gratefully acknowledge technical assistance from Drs Casey Korecki and Marc Levenston for providing immunohistochemistry in Fig. 1 . We also gratefully acknowledge Dr Devina Purmessur for providing data on PBS injection into IVD organ culture models in Fig. 2 .
PY - 2013/3
Y1 - 2013/3
N2 - Background context: Degeneration and injuries of the intervertebral disc (IVD) result in large alterations in biomechanical behaviors. Repair strategies using biomaterials can be optimized based on the biomechanical and biological requirements of the IVD. Purpose: To review the present literature on the effects of degeneration, simulated degeneration, and injury on biomechanics of the IVD, with special attention paid to needle puncture injuries, which are a pathway for diagnostics and regenerative therapies and the promising biomaterials for disc repair with a focus on how those biomaterials may promote biomechanical repair. Study design: A narrative review to evaluate the role of biomechanics on disc degeneration and regenerative therapies with a focus on what biomechanical properties need to be repaired and how to evaluate and accomplish such repairs using biomaterials. Model systems for the screening of such repair strategies are also briefly described. Methods: Articles were selected from two main PubMed searches using keywords: intervertebral AND biomechanics (1,823 articles) and intervertebral AND biomaterials (361 articles). Additional keywords (injury, needle puncture, nucleus pressurization, biomaterials, hydrogel, sealant, tissue engineering) were used to narrow the articles down to the topics most relevant to this review. Results: Degeneration and acute disc injuries have the capacity to influence nucleus pulposus (NP) pressurization and annulus fibrosus (AF) integrity, which are necessary for an effective disc function and, therefore, require repair. Needle injection injuries are of particular clinical relevance with the potential to influence disc biomechanics, cellularity, and metabolism, yet these effects are localized or small and more research is required to evaluate and reduce the potential clinical morbidity using such techniques. NP replacement strategies, such as hydrogels, are required to restore the NP pressurization or the lost volume. AF repair strategies including cross-linked hydrogels, fibrous composites, and sealants offer promise for regenerative therapies to restore AF integrity. Tissue engineered IVD structures, as a single implantable construct, may promote greater tissue integration due to the improved repair capacity of the vertebral bone. Conclusions: IVD height, neutral zone characteristics, and torsional biomechanics are sensitive to specific alterations in the NP pressurization and AF integrity and must be addressed for an effective functional repair. Synthetic and natural biomaterials offer promise for NP replacement, AF repair, as an AF sealant, or whole disc replacement. Meeting mechanical and biological compatibilities are necessary for the efficacy and longevity of the repair.
AB - Background context: Degeneration and injuries of the intervertebral disc (IVD) result in large alterations in biomechanical behaviors. Repair strategies using biomaterials can be optimized based on the biomechanical and biological requirements of the IVD. Purpose: To review the present literature on the effects of degeneration, simulated degeneration, and injury on biomechanics of the IVD, with special attention paid to needle puncture injuries, which are a pathway for diagnostics and regenerative therapies and the promising biomaterials for disc repair with a focus on how those biomaterials may promote biomechanical repair. Study design: A narrative review to evaluate the role of biomechanics on disc degeneration and regenerative therapies with a focus on what biomechanical properties need to be repaired and how to evaluate and accomplish such repairs using biomaterials. Model systems for the screening of such repair strategies are also briefly described. Methods: Articles were selected from two main PubMed searches using keywords: intervertebral AND biomechanics (1,823 articles) and intervertebral AND biomaterials (361 articles). Additional keywords (injury, needle puncture, nucleus pressurization, biomaterials, hydrogel, sealant, tissue engineering) were used to narrow the articles down to the topics most relevant to this review. Results: Degeneration and acute disc injuries have the capacity to influence nucleus pulposus (NP) pressurization and annulus fibrosus (AF) integrity, which are necessary for an effective disc function and, therefore, require repair. Needle injection injuries are of particular clinical relevance with the potential to influence disc biomechanics, cellularity, and metabolism, yet these effects are localized or small and more research is required to evaluate and reduce the potential clinical morbidity using such techniques. NP replacement strategies, such as hydrogels, are required to restore the NP pressurization or the lost volume. AF repair strategies including cross-linked hydrogels, fibrous composites, and sealants offer promise for regenerative therapies to restore AF integrity. Tissue engineered IVD structures, as a single implantable construct, may promote greater tissue integration due to the improved repair capacity of the vertebral bone. Conclusions: IVD height, neutral zone characteristics, and torsional biomechanics are sensitive to specific alterations in the NP pressurization and AF integrity and must be addressed for an effective functional repair. Synthetic and natural biomaterials offer promise for NP replacement, AF repair, as an AF sealant, or whole disc replacement. Meeting mechanical and biological compatibilities are necessary for the efficacy and longevity of the repair.
KW - Annulus fibrosus sealant
KW - Biomechanics
KW - Discography
KW - Intervertebral disc degeneration
KW - Tissue engineering
UR - http://www.scopus.com/inward/record.url?scp=84875503130&partnerID=8YFLogxK
U2 - 10.1016/j.spinee.2012.12.002
DO - 10.1016/j.spinee.2012.12.002
M3 - Article
C2 - 23369494
AN - SCOPUS:84875503130
SN - 1529-9430
VL - 13
SP - 243
EP - 262
JO - Spine Journal
JF - Spine Journal
IS - 3
ER -