Ultrasound-Guided Pulsed Radiofrequency Added to Perineural Steroid Injection Versus Perineural Steroid Injection Alone in the Treatment of Tarsal Tunnel Syndrome

Participants undergo ultrasound-guided pulsed radiofrequency (PRF) adjacent to the posterior tibial nerve using a 22-gauge cannula with a 5 mm active tip (parameters: pulse width 20 ms, frequency 2 Hz, output 45 V, maximum tip temperature 42°C, delivered for 480 seconds in two consecutive 240-second cycles). Following PRF, a 10 mL perineural injectate (8 mL dextrose 5%, 1 mL triamcinolone acetonide 40 mg, and 1 mL lidocaine 1%) is administered around the nerve (approximately 5 mL superficial and 5 mL deep).

Under real-time ultrasound guidance, a 22-gauge, 54-mm radiofrequency cannula with a 5-mm active tip is placed adjacent to the posterior tibial nerve. Sensory (50 Hz, ≤0.5 V) and motor (2 Hz, >0.5 V) stimulation are confirmed, followed by active pulsed radiofrequency (PRF) delivery (parameters: 42°C maximum tip temperature, 45 V, 2 Hz, 20 ms pulse width, for 480 seconds delivered as two consecutive 240-second cycles). Immediately following PRF, a 10 mL solution (8 mL dextrose 5%, 1 mL triamcinolone acetonide 40 mg, and 1 mL lidocaine 1%) is injected through the same cannula around the nerve (5 mL superficial and 5 mL deep).

Participants undergo the identical ultrasound-guided cannula placement and sensory/motor nerve stimulation protocol, after which the cannula is left in position for 480 seconds with the radiofrequency generator switched off (sham PRF). Following the sham phase, the identical 10 mL perineural injectate (8 mL dextrose 5%, 1 mL triamcinolone acetonide 40 mg, and 1 mL lidocaine 1%) is administered around the posterior tibial nerve.

Under real-time ultrasound guidance, the cannula is positioned adjacent to the posterior tibial nerve using the identical technique, followed by identical sensory and motor stimulation testing. The cannula is maintained in place for 480 seconds with the radiofrequency generator switched off (sham PRF). Immediately following the sham phase, the identical 10 mL solution (8 mL dextrose 5%, 1 mL triamcinolone acetonide 40 mg, and 1 mL lidocaine 1%) is injected around the nerve (5 mL superficial and 5 mL deep).

Pain intensity is assessed using a 10-cm Visual Analogue Scale (VAS), where 0 indicates "no pain" and 10 indicates "worst pain imaginable" (higher scores indicate worse pain). The change in foot and heel pain and paresthesia from baseline to 6 months post-intervention will be evaluated.