Electrospun PLGA and β-TCP (Rebossis-85) in a Lapine Posterolateral Fusion Model

Area of Science:

• Orthopedic Surgery
• Biomaterials Science
• Regenerative Medicine

Background:

• Calcium phosphate materials are widely used as bone void fillers.
• ReBOSSIS-85 (RB-85) is a synthetic, bioresorbable bone void filler with a unique handling characteristic.
• The study compares RB-85 to a predicate material in a posterolateral spine fusion model.

Purpose of the Study:

• To evaluate the in vivo performance of RB-85 as a bone void filler.
• To compare RB-85 with Mastergraft Putty when combined with bone marrow aspirate and iliac crest autograft.
• To assess the efficacy of different masses of RB-85 in a rabbit posterolateral spine fusion model.

Main Methods:

• A posterolateral spine fusion was performed in 150 skeletally mature rabbits.
• Rabbits received iliac crest bone graft (ICBG), Mastergraft Putty + ICBG, or RB-85 + ICBG (0.2-0.6g).
• Radiography, manual palpation, flexibility testing, MicroCT, and histology were used for assessment at 4, 8, and 12 weeks.

Main Results:

• All groups showed normal healing responses radiographically.
• Fusion rates at 12 weeks varied: ICBG (50%), Mastergraft Putty (50%), RB-85-0.2g (0%), RB-85-0.3g (25%), RB-85-0.45g (36%), RB-85-0.6g (50%).
• Histopathology revealed mild inflammation resolving by 12 weeks, with increasing new bone formation and graft resorption over time.

Conclusions:

• ReBOSSIS-85 is biocompatible and demonstrates normal healing features when used with autograft as an extender.
• Higher masses of RB-85 showed increased effectiveness in promoting spinal fusion.
• RB-85 can serve as an effective bone graft extender, reducing the need for large amounts of autograft.