Evaluation of thoracic sympathetic ganglion block as a predictor for response to ketamine infusion therapy and spinal cord stimulation in patients with chronic upper extremity pain.

A retrospective study at a single tertiary hospital examined whether a positive response to thoracic sympathetic ganglion block (TSGB) predicts outcomes of ketamine infusion therapy (KIT) and spinal-cord stimulation (SCS) in patients with chronic upper-extremity pain, including complex regional pain syndrome. Among 33 patients who received KIT, 60.6% reported a pain reduction of at least 2 points on a 0-10 scale. Positive TSGB response occurred in 70.0% of KIT responders, significantly higher than the 30.8% in non-responders, with a sevenfold increased odds of positive KIT outcome. Among 32 SCS patients, 68.8% experienced short-term effectiveness; positive TSGB response was 45.5% in responders versus 0.0% in non-responders.

Study at a glance

Abstract

To investigate the predictive value of thoracic sympathetic ganglion block (TSGB) in response to ketamine infusion therapy (KIT) and spinal-cord stimulation (SCS) in patients with chronic upper-extremity pain including complex regional pain syndrome (CRPS). Retrospective. Tertiary hospital single-center. Patients who underwent TSGB receiving KIT or SCS within a 3-year window. Positive TSGB outcomes were defined as ≥2 0-10 Numerical Rating Scale (NRS) score reduction at 2 weeks post-procedure. Positive KIT and SCS outcomes were determined by ≥2 NRS score reduction at 2-4 weeks post-KIT and ≥4 NRS score reduction at 2-4 weeks post-SCS implantation, respectively. Among 207 patients who underwent TSGB, 38 received KIT and 34 underwent SCS implantation within 3 years post-TSGB; 33 patients receiving KIT and 32 patients receiving SCS were included. Among 33 patients who received KIT, 60.6% (n = 20) reported a ≥ 2 0-10 NRS pain-score reduction. Positive response to TSGB occurred in 70.0% (n = 14) KIT responders, significantly higher than that in 30.8% (n = 4) KIT non-responders. Multivariable analysis revealed a positive association between positive responses to TSGB and KIT (OR 7.004, 95% CI 1.26-39.02). Among 32 patients who underwent SCS implantation, 68.8% (n = 22) experienced short-term effectiveness. Positive response to TSGB was significantly higher in SCS responders (45.5%, n = 10) than in non-responders (0.0%). However, there were no associations between pain reduction post-TSGB and that post-KIT or post-SCS. A positive response to TSGB is a potential predictor for positive KIT and SCS outcomes among patients with chronic upper-extremity pain, including CRPS.