This research proposal aims to investigate the potential use of Infrared (FLIR) imaging to monitor the successful achievement of the sympathetic blockade in patients with complex regional pain syndrome (CRPS).

Sympathetic blocks are clinically used to diagnose and treat sympathetically mediated pain. Despite the frequent use of these blocks, there remains a need for an objective method to determine the achievement of a sympathetic block in the clinical setting.

Current clinical practice assess the success of a sympathetic block by observation of clinical signs of sympathetic blockade. These signs include monitoring skin temperature, pulse amplitude, blood oxygen, or any combination of these methods. However, clinical signs of sympathetic blockade often demonstrate an unpredictable or delayed response and can make monitoring difficult.

Therefore, it is necessary to develop an objective monitoring method that is reliable, rapid response, and not affected by the other confounders. One potential method is the use of thermal camera imaging (FLIR).

Such a monitor could increase procedural accuracy and efficiency, thus improving patient care. To plan the prospective treatment options, objective confirmation of successful sympathetic block is essential to differentiate sympathetically mediated pain (SMP) versus sympathetically independent pain (SIP).

In this context, utilization of a monitor with a rapid response and easy clinical applicability, would serve as an objective endpoint for evaluating sympathetic blockade both clinically and for future research.

Therefore, this research proposal aims to investigate the infrared (FLIR) thermal camera as an objective method for determining the achievement of sympathetic block in the clinical setting.

Inclusion Criteria:

• The patient is between 18 and 85 years old
• Providing CRPS diagnostic criteria by using Budapest Clinical criteria [16]
• The patient has had pain and other symptoms for more than 3 months
• Not responding to conventional medical treatments and multidisciplinary approach
• High NRS detection in pain assessment despite appropriate treatment (NRS = and > 6/10).
• Pain is a limitation in the patient's functional capacity despite appropriate treatment.

Exclusion Criteria:

• Patients with suspected disc herniation, spinal stenosis, myelopathy, and suspected radiculopathy in detailed examinations and examinations (MRI, CT).
• Systemic or local infection
• Coagulation disorders
• History of allergy to contrast material
• Malignancy
• Pregnancy
• Uncontrollable medical and psychiatric condition
• The patients diagnosed with dysautonomia, sympathetic dysfunction (such as Raynaud disease or Buerger disease), sweating disorders (such as acquired idiopathic generalized anhidrosis), and patients on vasoactive drugs, the mechanism of action is directly on the vascular tone.

This study is designed to be implemented in a single center in an academic pain center that is specialized in musculoskeletal pain. In a pain center with a high experience in clinical and academic fields, it is planned to apply lumbar sympathetic blocks to the patients diagnosed with CRPS. The Budapest Clinical Diagnostic Criteria will be used to diagnose CRPS Type 1 patients.

There is no plan to share individual patient data with other researchers.