Percutaneous Cryoneurolysis for Upper Limb Spasticity: A Systematic Scoping Review of Current Evidence, Safety...

Background/Objectives: Percutaneous cryoneurolysis (CNL) has emerged as a minimally invasive neuromodulatory technique for focal spasticity management, with growing international clinical adoption since 2018. Its application to upper limb motor nerve targets-including branches of the musculocutaneous, radial, median, ulnar, pectoral, and thoracodorsal nerves-is of direct relevance to clinicians involved in the surgical and non-surgical management of hand and upper extremity spasticity. The existing literature lacks a comprehensive systematic appraisal of its evidence base. This systematic scoping review aimed to map all published evidence on CNL for spasticity across all aetiological groups and anatomical regions, with particular attention to upper limb and hand-relevant targets; appraise methodological quality using design-appropriate tools; characterise the safety profile; apply the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework to key outcome domains; and identify critical evidence gaps. Methods: A systematic scoping review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines (search through February 2026). PubMed/MEDLINE, Embase (via Ovid), Scopus, and the Cochrane Library were searched. Methodological quality was assessed using JBI Critical Appraisal Checklists, Risk Of Bias In Non-randomised Studies of Interventions (ROBINS-I), and A MeaSurement Tool to Assess systematic Reviews-2 (AMSTAR-2). Certainty of evidence was evaluated using GRADE. Results: Twenty-five studies met inclusion criteria; no randomised controlled trials (RCTs) were identified. In the largest prospective observational cohort (n = 59, 12-month follow-up), CNL produced statistically significant improvements in passive range of motion (ROM), Modified Ashworth Scale (MAS) scores, and pain in patients with upper limb spasticity refractory to botulinum toxin type A (BoNT-A). A prospective safety study (n = 113 patients; 277 nerves) documented that 96.75% of nerve treatments produced no post-procedural sensory disturbance; the risk was approximately 10-fold higher for mixed sensorimotor than purely motor nerve targets (7.1% vs. 1.1%). Certainty of evidence was Very Low (⊕◯◯◯) for all efficacy outcomes and Low (⊕⊕◯◯) for safety. Conclusions: CNL represents a mechanistically sound second-line or complementary intervention for refractory focal spasticity. In the upper extremity context, it may additionally serve as a reversible functional evaluation tool before irreversible surgical decisions-including selective neurotomy-are made. The evidence base is critically constrained by the absence of RCTs, confirmed cohort overlap between the two largest primary studies, financial conflicts of interest with the primary device manufacturer identified in ≥48% of included studies (≥12/25), and single-institution concentration of primary evidence (≥69% of primary clinical studies from one research group). Multiple ongoing controlled trials are expected to provide higher-quality evidence to inform guideline development.