Bionate^® nucleus disc replacement: bench testing comparing two different designs

Area of Science:

• Biomaterials Science
• Orthopedic Surgery
• Mechanical Engineering

Background:

• Intervertebral disc degeneration is a primary cause of chronic low back pain.
• Current nucleus replacement strategies aim to restore disc function but have limitations.
• Developing implants that replicate native disc biomechanics is crucial for effective treatment.

Purpose of the Study:

• To design and evaluate a novel intervertebral disc nucleus replacement implant.
• To compare the biomechanical performance of two implant designs (D1 and D2) under various loading conditions.
• To assess the wear characteristics and mechanical endurance of the implants.

Main Methods:

• Two implant designs (D1 and D2) were fabricated and subjected to static and fatigue testing according to ASTM standards.
• Implant stiffness and compression were analyzed under different load ranges.
• Wear tests were conducted following ISO standards, with data analyzed using GNU Octave and R statistical software.

Main Results:

• D1 exhibited superior performance in unconfined compression tests and showed less deformation than D2.
• While both designs endured compression fatigue, D2 experienced significantly higher wear and permanent width deformation.
• D1 demonstrated more homogeneous behavior, lower wear, and good mechanical endurance, with no functional failure after long-term testing.

Conclusions:

• The D1 implant design outperformed D2 in biomechanical testing and wear resistance.
• D1 shows potential for clinical application in nucleus replacement surgery.
• Further investigation in cadaveric specimens and clinical trials is recommended.