Multicenter Prospective Randomized Comparison of Ultrasound-Guided Stellate Ganglion Versus Thoracic Paravertebral Block for Sympathetic Blockade in Chronic Upper Extremity Pain.

BACKGROUND

Stellate ganglion block (SGB) is a type of sympathetic block used to relieve pain in the face and upper extremities. However, its effectiveness can be limited by the presence of Kuntz fibers that bypass the stellate ganglion. Thoracic paravertebral block (TPVB) offers an alternative in such cases. We hypothesized that ultrasound (US)-guided TPVB would provide a higher success rate of upper extremity sympathetic blockade than US-guided SGB. Therefore, this prospective randomized study aimed to compare the technical success rates between US-guided TPVB and US-guided SGB and assess clinical outcomes in alleviating upper extremity pain.

METHODS

Patients aged 19 to 85 years diagnosed with chronic upper extremity pain (complex regional pain syndrome and neuropathic pain) were randomly assigned to either the US-guided TPVB group, where they received a 10 mL injection of 1% mepivacaine in the T2 paravertebral space, or the US-guided SGB group, where they received a 5 mL injection of 1% mepivacaine at the C6 level. The primary outcome was the success rate (%) of sympathetic blockade, which was predefined as the difference in temperature change between affected and unaffected hands 20 minutes after the procedure (ΔT difference) of ≥ 1.5°C. Secondary outcomes included comparisons of the ΔT difference (°C), differences in peak systolic velocities (cm/s) of the ipsilateral brachial artery at 20 minutes, and pain intensity at baseline and 20 minutes, 1 week, and 4 weeks after the procedure using an 11-point numerical rating scale (NRS) pain score.

RESULTS

The TPVB group (N = 22/35, 62.9%) showed a higher success rate than the SGB group (N = 13/34, 38.2%; P = .041) in achieving the primary outcome of sympathetic blockade at 20 minutes. The difference in success rates between the 2 groups was 24.6 % (95% confidence interval [CI], -9.0% to 58.2%). The ΔT difference was significantly higher in TPVB than in SGB (2.0°C ±1.5 and 1.1°C ±1.3, respectively; P = .008). The peak systolic velocities at 20 minutes increased in TPVB (P = .005), which was not observed in SGB (P = .325). Pain intensity decreased in both groups 20 minutes after injection (P < .001 in each group), and the TPVB group showed a lower 11-point NRS pain score compared to the SGB group (4.3 ± 2.2 and 5.4 ± 2.4, respectively; P = .038). Pain intensity scores increased to preintervention levels in both groups at 1 week and 4 weeks after the interventions.

CONCLUSIONS

US-guided TPVB had a higher success rate of upper extremity sympathetic blockade than US-guided SGB, with more pronounced immediate postprocedural pain relief.