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Abstract
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Background and Aims Lumbar sympathetic ganglion neurolysis (LSGN) has been used for long-term pain relief in patients with complex regional pain syndrome (CRPS). However, the actual effect duration of LSGN has not been accurately measured. This prospective observational study measured the effect duration of LSGN in CRPS patients and investigated the relationship between temperature change and pain relief.
Methods After performing LSGN with 2.5 mL of 99% ethanol, the skin temperatures of both the maximum pain site and the plantar area in the affected and unaffected limbs were measured by infrared thermography (figure 1, 2), and pain intensity was assessed before and at 2 weeks, 1 month, and 3 months. The median time to return to baseline temperature was calculated using survival analysis.
Results The skin temperature increased significantly at all-time points relative to baseline in both regions (maximum pain site: 1.4°C ± 1.0°C, plantar region: 1.28°C ± 0.8°C, all P < 0.001). The median time to return to baseline temperature was 12 (95% confidence interval [CI]: 7.7–16.3) weeks at the maximum pain site and 12 (95% CI: 9.4–14.6) weeks at the plantar area. Pain intensity decreased significantly relative to baseline, at all-time points after LSGN. (Figure 3, 4)
Infrared thermographic images of a 26-year-old patient with complex regional pain syndrome type 1, showing results in the lower extremities. The maximum pain site of this patient was the left knee (yellow arrows). The skin temperature differences between the affected and unaffected site (ΔT) at three time points are illustrated. (A) Baseline ΔT = -1.5°C; (B) ΔT immediately after lumbar sympathetic neurolysis = 2.1°C; (C) ΔT two weeks after LSGN = −0.4°C. The numbers in the square brackets indicates the numbers of the region of interest. Figure 2 CONSORT diagram of the patients included in this study. CRPS: complex regional pain syndrome, LSGB: lumbar sympathetic ganglion block, LSGN: lumbar sympathetic ganglion neurolysis
Skin-temperature change at the maximum pain site (A) and plantar area (B) and the patients’ pain intensity (C) pre-LSGN (baseline), post-LSGN, and 2 weeks, 1 month, and 3 months after LSGN (*P < 0.001 compared with pre-LSGN, †P < 0.001 compared with the previous time point). There was a significant increase in temperature in both regions and a decrease in the patient’s pain at all time points relative to baseline. LSGN: lumbar sympathetic neurolysis
Kaplan–Meier survival analysis of the effect duration of lumbar sympathetic neurolysis. The median time to return to baseline temperature was 12 weeks (95% confidence interval [CI], 7.6–16.3 weeks) at the maximum pain site (A) and 12 weeks (95% CI, 9.4–14.6 weeks) in the plantar area (B)
Conclusions The effect of LSGN on reducing pain and increasing temperature in the affected extremity was sustained for ≤ 12 weeks post-treatment, with a significant reduction in pain intensity after LSGN. These results support the use of LSGN as a prolonged pain management strategy in patients with CRPS.