A Multi-component Fiber-reinforced PHEMA-based Hydrogel/HAPEX^TM Device for Customized Intervertebral Disc Prosthesis

Abstract

Spinal disease due to intervertebral disc degeneration represents a serious medical problem which affects many people worldwide. Disc arthroplasty may be considered the future ''gold standard'' of back pain treatment, even if problems related to available disc prostheses are considered. Hence, the aim of the present study was to improve the artificial disc technology by proposing the engineering of a pilot-scale device production process for a total multi-component intervertebral disc prosthesis. The device is made up of a poly(2-hydroxyethyl methacrylate)/poly(methyl methacrylate) (PHEMA/PMMA) (80/20 w/w) semi-interpenetrating polymer network (s-IPN) composite hydrogel reinforced with poly(ethylene terephthalate) (PET) fibers as annulus/nucleus substitute, and two hydroxyapatite-reinforced polyethylene composite (HAPEX™) endplates in order to anchor the multi-component device to the vertebral bodies. Static and dynamic-mechanical characterization show appropriate mechanical behavior. An example of engineering of a suitable pilot-scale device production process is also proposed in order to manufacture custom made implants.

Hydrogel-Based Platforms for the Regeneration of Osteochondral Tissue and Intervertebral Disc

“…IVD degeneration represents a spinal disease. Even though discectomy and fusion are the two most common surgical approaches for treating a degenerated disc, they are far from ideal treatments since they alter the biomechanics of the spine [90,[94][95][96][97][98][99]. For this reason, the ideal solution to a degenerated disc would involve an artificial disc [90,91,94,[97][98][99][100].…”

“…It has been well reported that the intervertebral disc prostheses currently available on the market undergo failure mainly because of wear or mismatch between the mechanical proprieties of the implanted device and the natural tissue [99,101]. In addition, current disc prostheses basically consist of a polymeric core interposed between two metallic plates (i.e., LINK SB Charite and ProDisc) possessing standard sizes [99][100][101][102][103].…”

“…Soft biological tissues show high strength, flexibility and toughness, and materials with a single structural arrangement do not allow combination of all these features [90,99,100]. Accordingly, a biomimetic approach has been adopted to reproduce the structure of the natural disc involving the use of hydrogels, in order to overcome the drawbacks related to the use of current prostheses.…”

“…Initially, poly(2-hydroxyethylmethacrylate) (PHEMA) hydrogels were considered in designing innovative disc prostheses because of their biocompatibility, high permeability and high hydrophilicity [7,99,104,105]. However, it is well documented that in the swollen state the mechanical performances of these materials are not appropriate for load-bearing biomedical applications [99,104,106,107].…”

Interfacial and biological properties of the gradient coating on polyamide substrate for bone substitute

“…Nano-hydroxyapatite (nHA), owing to its chemical similarity to the inorganic component of natural bone, has been widely used for bioactive coating of orthopaedic implants [12,13,[16][17][18]. To improve the integration ability of the implants with the nearby bone tissues, a number of different coating techniques have been employed for the preparation of nHA-coated implants, which includes solution-based techniques [4,19,20], ionic sputtering [21,22] and plasma spraying [23,24].…”