Pulsed Radiofrequency One or Three Nerves for Chronic Shoulder Pain. A Prospective, Randomized, Double-blind Study

Pulsed radiofrequency (PRF) neuromodulation / or ablation is an interventional pain management method. Clinical use of PRF for shoulder pain management generally focuses on the suprascapular nerve, what is considered a safe and superior to placebo and physiotherapy. We study the use of the PRF neuromodulation the suprascapular, axillary, and articular branches of the lateral pectoral nerve, as well as the effectiveness of this combined technique compared to the PRF of the suprascapular nerve alone

Background: It's believed that PRf of the suprascapular nerve is a safe and reliable treatment for shoulder pain. But PRF of the suprascapular nerve may be less effective than intra-articular steroid injections (Eyigor et al., 2010). There is also evidence that even test, diagnostic suprascapular nerve blockade in some patients may not give a satisfactory analgesic effect (Sinha et al., 2020). Probably, the unsatisfactory results of PRF suprascapular nerve as a search for a solution force the use of standard thermal RF ablation. (Bone et al., 2013) It is possible to expect a greater clinical effect from the combination of PRF of the three main articular nerves of the suprascapular, axillary and lateral pectoral nerves than from PRF of the suprascapular nerve alone. Nevertheless, having the task of obtaining the maximum effect from PRF, it seems important to maintain a balance between inevitable intervention and excessive intervention, considering that any intervention is associated with the risk of complications.

Methods: The study is planned to include 142 adult patients who are planned to have PRF of the suprascapular nerve due to the presence of chronic shoulder pain.The study is planned as a prospective randomized double-blind controlled trial. According to inclusion / exclusion criteria, written informed consent signing, patients will be randomized in a 1: 1 ratio into two groups: PRF of the suprascapular nerve (n=71) and PRF of the suprascapular, axillary and lateral pectoral nerves (n=71). Patients will be evaluated by a physician 4 weeks and 16 weeks after discharge to receive information on treatment results.

Sample size assessment: To identify differences of 5 points on the SPADI scale at a 5% significance level with 80% power, assuming an expected mean SPADI of 25.5 points and SD - 10.1 according to the study by Korkmaz et al 2010, 64 people will be required for each group. The number 128 was increased to 142 in the sample in order to compensate for observation losses.

Eligibility Criteria:
Inclusion Criteria:

1. Chronic pain (existing for more than three months at the time of examination) in the shoulder associated with the following pathology:

   * rotator cuff injury
   * adhesive capsulitis
   * arthrosis of the shoulder joint
   * arthrosis of the acromioclavicular joint
   * subacromial impingement syndrome
   * a history of arthroscopic surgery
2. Signed informed consent to participate in the study
3. Lack of indications for shoulder surgery
4. Age\> 18 years old 5 The positive effect of the test blockade of the suprascapular, axillary and lateral thoracic nerves with a local anesthetic (reduction of the pain level from the baseline according to NRS by at least 50%)

Exclusion Criteria:

1. Rotator cuff calcific tendinopathy
2. infectious arthritis
3. Instability of the shoulder joint
4. cervical radiculopathy
5. contraindications to local anesthetics
6. coagulopathy and anticoagulant therapy
7. pregnancy
8. oncology
9. the impossibility of subjective assessment of the level of pain and function of the joint