Interventional Pain Procedures: A Narrative Review Focusing on Safety and Complications. Part 4 - Peripheral Nerve,...

The first three installments of this series examined the safety and complications of injections for spinal pain (Part 1), interventional procedures for back pain (Part 2), and sympathetic and ganglion-targeted techniques (Part 3). This fourth and concluding article addresses the interventions performed away from the neuraxis and the sympathetic chain, which together account for much of everyday pain practice: peripheral and cranial nerve procedures (blocks, chemical neurolysis, radiofrequency, cryoneurolysis, and peripheral or occipital nerve stimulation); joint, bursal, and tendon injections; regenerative or orthobiologic injections; chemodenervation with botulinum toxin; sacroiliac and musculoskeletal soft-tissue procedures; interventions for painful neuroma; and percutaneous ablation of painful bone metastases. Each family carries a characteristic and occasionally serious spectrum of adverse events: local-anesthetic systemic toxicity, pneumothorax, and nerve injury with peripheral and truncal blocks; post-procedural neuritis, thermal injury, and neuroma with radiofrequency and cryoneurolysis; device-related events with peripheral and occipital stimulation; septic arthritis, chondrotoxicity, and the recently recognized structural joint effects of intra-articular corticosteroids; standardization and regulatory concerns with orthobiologics; local weakness, dysphagia, and toxin spread with botulinum toxin; thermal or cryo injury to adjacent structures and pathological fracture with percutaneous ablation of bone metastases; and largely transient events after sacroiliac joint and musculoskeletal soft-tissue procedures. We also address a category common to almost all of these procedures but seldom reviewed: the complications specific to ultrasound guidance itself, chiefly infection from contaminated gel or transducers and the pitfalls of needle-tip visualization. Because most of these targets are superficial and amenable to ultrasound guidance, the reported safety profile is generally favorable; however, this synthesis is narrative and qualitative, and much of the underlying evidence derives from case reports, small series, and heterogeneous cohorts, so a low reported complication burden should not be equated with a precisely established low incidence. As throughout the series, appropriate patient selection, real-time image guidance, aseptic technique, dose and volume limitation, and attention to antithrombotic status are the recurring determinants of safety.