Benefits of Steroid Injections into Paraspinous Muscles After Spinal Surgery in a Rat Paraspinal Muscle Retraction...

Area of Science:

• Orthopedics
• Regenerative Medicine
• Pharmacology

Background:

• Open posterior lumbar surgery requires detaching paraspinal muscles, leading to muscle injury, inflammation, and fibrosis.
• Corticosteroids possess known anti-inflammatory properties that may mitigate surgical muscle damage.

Purpose of the Study:

• To evaluate the protective effects of intramuscular corticosteroid injections on paraspinal muscles after spinal surgery.
• To investigate the impact of steroids on muscle cell viability, inflammation, and regeneration markers.

Main Methods:

• In vitro: C2C12 cells exposed to hypoxia and LPS to simulate muscle injury.
• In vivo: Animal models underwent paraspinous muscle retraction followed by intramuscular steroid injection.
• Assessments included neurobehavioral tests, electrophysiology, and analysis of inflammatory and regeneration-related proteins.

Main Results:

• Steroids improved cell viability and reduced inflammatory markers (iNOS, COX2) and apoptosis (Bad, Bax).
• Intramuscular steroid injections improved neurobehavioral outcomes and electrophysiological measures of muscle denervation.
• Steroid treatment attenuated inflammatory markers in dorsal root ganglia and restored muscle-specific proteins (AChR, desmin), reducing fibrosis.

Conclusions:

• Intramuscular corticosteroid injection effectively protects paraspinal muscles against damage induced by surgical retraction.
• This therapeutic approach may offer significant benefits for muscle recovery and function following spinal operations.