Innovative hydrogel-patch combination for large annulus fibrosus defects: a prospective approach to address...

Area of Science:

• Biomaterials science
• Spinal surgery
• Regenerative medicine

Background:

• Large annulus fibrosus (AF) defects increase reherniation risk, especially in the medial region with poor self-healing.
• The rising incidence of herniated discs necessitates advanced repair strategies.

Purpose of the Study:

• To design an annulus fibrosus (AF) repair technique addressing insufficient mechanical properties and poor sealing capacity.
• To evaluate novel repair strategies for large AF defects.

Main Methods:

• In vitro biomechanical testing and finite element analysis were employed.
• Five repair techniques were assessed: hydrogel filler (HF), medial barrier (MB) patch, MB with HF (MB&HF), medial-lateral barrier (MLB) patch, and MLB with HF (MLB&HF).
• Evaluations included repair tightness, spinal stability, and fatigue resistance under simulated lumbar spine loading.

Main Results:

• The MLB&HF technique demonstrated the most effective recovery of intervertebral disc (IVD) stiffness (-24.13% ± 3.59%).
• Hydrogel filler best maintained IVD height, and combined patch-hydrogel repair substantially reduced and distributed AF stress.
• The MLB&HF technique showed the lowest patch deformation and suture stress, indicating superior mechanical integrity.

Conclusions:

• Combined annulus fibrosus (AF) patch and hydrogel repair offers promising mechanical properties for postdiscectomy treatment.
• This biomaterial approach presents a viable solution for large AF defects, enhancing disc stability.
• The study introduces a promising method for clinical AF repair product development.