Quantitative Analysis of Real-Time Infrared Thermography for the Assessment of Lumbar Sympathetic Blocks: A Preliminary Study

Abstract

Lumbar sympathetic blocks (LSBs) are commonly performed to treat pain ailments in the lower limbs. LSBs involve injecting local anesthetic around the nerves. The injection is guided by fluoroscopy which is sometimes considered to be insufficiently accurate. The main aim was to analyze the plantar foot skin temperature data acquired while performing LSBs in patients with complex regional pain syndrome (CRPS) affecting the lower limbs. Forty-four LSBs for treating lower limb CRPS in 13 patients were assessed. Pain medicine physicians visualized the infrared thermography (IRT) video in real time and classified the performance depending on the observed thermal changes within the first 4 min. Thirty-two percent of the cases did not register temperature variations after lidocaine was injected, requiring the needle to be relocated. Differences between moments are indicated using the 95% confidence intervals of the differences (CI 95%), the Cohen effect size (ES) and the significance (p value). In successful cases, after injecting lidocaine, increases at minute 7 for the mean (CI 95% (1.4, 2.1 °C), p < 0.001 and ES = 0.5), at minute 5 for maximum temperature (CI 95% (2.3, 3.3 °C), p < 0.001 and ES = 0.6) and at minute 6 for SD (CI 95% (0.2, 0.3 °C), p < 0.001 and ES = 0.5) were observed. The results of our preliminary study showed that the measurement of skin temperature in real time by infrared thermography is valuable for assessing the success of lumbar sympathetic blocks.

A Complex Regional Pain Syndrome Imaging Journal: Case Report

“…To standardize practice, the International Academy of Clinical Thermology (IACT) released guidelines in 2002 with the minimum characteristics necessary for infrared thermography use in clinical practice, which includes guidelines on training staff, laboratory requirements, device specifications, imaging and patient management protocols, and modalities on data reporting. 9 When measurement parameters are well controlled in this manner, infrared thermography has demonstrated accuracy and precision in CRPS 10–13 and has been recognized as a valuable diagnostic tool, particularly in atypical cases of CRPS 14 or when disease burden waxes and wanes, as in our case. In a separate study, infrared thermography was used to develop a marker of disease severity in CRPS, non-CRPS painful limb conditions, and healthy controls.…”

“…7,8 In addition, infrared thermal imaging has been applied to the assessment of efficacy of lumbar sympathetic blocks in CRPS. 12,13 While our report is limited by the patient's willingness to provide consistent and honest measurements (eg, consistent camera distance, stable ambient temperature, and high-resolution images free of artifact or falsification), the infrared images he provided facilitated CRPS diagnosis and aided treatment monitoring throughout the disease course. Moreover, his journal stimulated more thoughtful clinicianpatient discussions about the nature of CRPS and seemed to strengthen the therapeutic alliance.…”

“…7,8 In addition, infrared thermal imaging has been applied to the assessment of efficacy of lumbar sympathetic blocks in CRPS. 12,13…”

The analgesic effect of lumbar sympathetic ganglion block in patients with failed back surgery syndrome

“…Blocking sympathetic neurons interrupts the positive feedback circuit and decreases central sensitization ( 9 ). Lumbar sympathetic ganglia are located at the anterolateral side of lumbar vertebrae via forming a synapse from pre and post-ganglionic fibers ( 13 , 14 ). Lumbar sympathetic ganglion block (LSGB) is indicated for diagnosis and treatment for painful conditions including CRPS, herpes zoster, phantom limb, diabetic neuropathy, or vascular pain of the legs ( 9 , 13 ).…”

“…Lumbar sympathetic ganglia are located at the anterolateral side of lumbar vertebrae via forming a synapse from pre and post-ganglionic fibers ( 13 , 14 ). Lumbar sympathetic ganglion block (LSGB) is indicated for diagnosis and treatment for painful conditions including CRPS, herpes zoster, phantom limb, diabetic neuropathy, or vascular pain of the legs ( 9 , 13 ). Patients with FBSS experience various natures of pain, including somatic components by neural injury and neuropathic components by nociceptive pain transmission from the disc and ligamentous tissue entering the sympathetic trunk via rami communicants ( 15 ).…”