Injectable, Moderately Adhesive, and Thermoresponsive Hydrogel for Preventing Disc Reherniation by Obstructing the...

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Spine Surgery

Background:

• Disc microdiscectomy recurrence affects up to 25% of patients due to annulus fibrosus limitations.
• Existing injectable hydrogels focus on nucleus pulposus replacement, not annulus fibrosus defect sealing.

Purpose of the Study:

• To introduce an injectable hydrogel (TX) for physical obstruction of annulus fibrosus defects post-microdiscectomy.
• To evaluate the physico-mechanical properties, optimal injection volume, and in vivo efficacy of the TX hydrogel for preventing disc reherniation.

Main Methods:

• Physico-mechanical characterization of TX hydrogel.
• Optimization of injection volume using an ex vivo bovine coccygeal spine model (0.5-1 kN load).
• In vivo evaluation of TX hydrogel in an ovine lumbar microdiscectomy model (5 levels, 6 animals).

Main Results:

• TX hydrogel demonstrated favorable physico-mechanical properties for lumbar disc application.
• Optimized injection volume was determined using the ex vivo model.
• In vivo studies showed reduced defect area and enhanced organized tissue formation at TX-treated sites compared to controls.

Conclusions:

• The injectable TX hydrogel effectively obstructs annulus fibrosus defects, preventing disc reherniation.
• TX hydrogel provides mechanical support, minimizes nucleus pulposus protrusion, and promotes annulus fibrosus sealing.
• This approach offers a promising strategy for improving outcomes after lumbar disc microdiscectomy.