Six-Month Outcomes of Ultrasound-Guided Five-Nerve Ankle Block and Perineural Hydrodissection as an Adjunct to Pharmacological Therapy in Patients with Painful Diabetic Peripheral Neuropathy: A Prospective Single-Arm Longitudinal Study

Abstract

Background: Painful diabetic peripheral neuropathy (PDPN) may remain symptomatic despite evidence-based pharmacological therapy. Peripheral nerve hydrodissection is a minimally invasive technique that may mechanically separate a nerve from surrounding tissues; however, direct evidence supporting its use in PDPN is limited. Objectives: This study evaluated six-month changes in pain, sleep-related patient-reported outcomes, and electrodiagnostic severity following a single standardized five-nerve ankle block with perineural hydrodissection in patients who remained symptomatic despite treatment with pregabalin and duloxetine. Methods: This prospective, single-arm, longitudinal study included 34 patients with PDPN and persistent pain despite pregabalin 75 mg twice daily and duloxetine 30 mg once daily. A single ultrasound-guided intervention targeted five standard ankle nerves. A total of 10 mL of injectate containing 1% lidocaine and 8 mg dexamethasone was used, with 2 mL administered around each nerve to achieve perineural hydrodissection. Pain was assessed at baseline and at 1, 3, and 6 months. Sleep was assessed at baseline and using overall sleep satisfaction at 6 months. Electrodiagnostic severity was assessed at baseline and at 6 months. Results: The mean age was 69.85 ± 4.38 years; 19 of 34 patients (55.9%) were male. The mean duration of diabetes was 20.56 ± 4.02 years, and the mean HbA1c was 7.04 ± 0.18%. Mean pain decreased from 7.76 ± 0.96 at baseline to 6.09 ± 1.00, 5.62 ± 0.82, and 5.32 ± 0.81 at 1, 3, and 6 months, respectively. The Friedman test showed a significant time effect (χ2 = 86.27, P < 0.001; Kendall’s W = 0.846). The mean baseline-to-6-month pain reduction was 2.44 points (95% CI, 2.18 - 2.71). The electrodiagnostic ordinal severity score decreased from 2.40 to 2.12 (Wilcoxon P < 0.001). Conclusions: In this uncontrolled cohort, the intervention was associated with significant improvements in pain and electrodiagnostic severity over 6 months. However, causality cannot be established without a control or sham group; therefore, the findings should be considered preliminary.