Indications, Trends, and Outcomes of Nerve Blocks for Spasticity Management: A Systematic Review

BackgroundSpasticity is a stretch reflex disorder, clinically characterized by increase in muscle tone and is often seen in upper motor neuron lesions, which can limit function in daily activities. While botulinum toxin injections are widely used treatment option, nerve blocks may offer complementary or alternative benefits.ObjectiveTo evaluate the indications, techniques, and clinical outcomes of nerve blocks for spasticity management.MethodsA literature search of major databases from July 2000- July 2025, identified studies on diagnostic nerve blocks, therapeutic neurolysis, and cryoneurolysis. Fourteen studies met inclusion criteria. Extracted data included patient characteristics, targeted nerves, agents and volumes, imaging guidance, tone reduction, functional outcomes, predictive value for BoNT, and adverse events. Due to heterogeneity in outcomes and methodologies, results were narratively synthesized.ResultsDiagnostic nerve blocks consistently aided treatment planning; one case-control study showed higher goal attainment (≈70% vs 40%) when diagnostic blocks guided BoNT injections. Phenol or alcohol neurolysis and cryoneurolysis produced meaningful spasticity reduction, typically improving Modified Ashworth Scale scores by 1-2 grades with effects lasting 3-6 months, often longer than BoNT. Across modalities, adverse events were uncommon and generally mild, most often transient pain or dysaesthesia. Publication trends showed increased use of ultrasound guidance and greater interest in diagnostic blocks and cryoneurolysis after 2018.ConclusionNerve Blocks are effective yet underused techniques that can provide rapid and sometimes durable spasticity reduction and support individualized long term rehabilitationplanning. Further standardized, long-term studies are needed to optimize their integration into multimodal spasticity care.