Robustly Injectable Tetra-PEG Hydrogel Sealants for Annulus Fibrosus Repair

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Spinal Surgery

Background:

• Discectomy for lumbar disc herniation can cause annular fibrosus defects, leading to recurrence.
• Endoscopic discectomy demands bioadhesives with rapid injectability, ease of use, and underwater adhesion.

Purpose of the Study:

• To develop and evaluate a rapidly in situ forming injectable tetra-PEG bioadhesive (ISG) for sutureless closure of annular fibrosus defects.

Main Methods:

• Formulation of ISG using FDA-approved tetra-armed poly(ethylene glycol) amine (tetra-PEG-NH2) and tetra-armed poly(ethylene glycol) succinimidyl glutarate (tetra-PEG-SG).
• Assessment of ISG properties including rapid network formation, waterproofness, adhesion, and compliance via ammonolysis reaction.
• In vivo evaluation in a goat lumbar discectomy model.

Main Results:

• ISG formed uniform networks within seconds, demonstrating easy injection, efficient waterproofness, and instant tissue adhesion.
• In vivo studies showed ISG effectively maintained disc height and fused with host tissue.
• ISG ameliorated intervertebral disc degeneration and retained initial biomechanics.

Conclusions:

• The developed ISG bioadhesive provides an efficient strategy for minimally invasive treatment of annular fibrosus defects.
• This injectable hydrogel shows promise for preventing disc herniation recurrence after discectomy.