Notch vs Midpoint Suprascapular Nerve PRF for Chronic Shoulder Pain

Chronic shoulder pain is a common musculoskeletal condition that significantly affects daily activities and quality of life. Rotator cuff tendinopathy is one of the most frequent causes of chronic shoulder pain. The suprascapular nerve plays a key role in shoulder pain transmission, and pulsed radiofrequency (PRF) of the suprascapular nerve has emerged as an effective minimally invasive treatment option.

Different anatomical approaches have been described for suprascapular nerve interventions, including the suprascapular notch and midpoint approaches. However, there is limited evidence comparing the clinical and functional outcomes of these approaches.

The aim of this prospective, randomized study is to compare the effects of PRF applied to the suprascapular nerve via suprascapular notch and midpoint approaches in patients with chronic shoulder pain due to rotator cuff tendinopathy. Patients will be randomly allocated into two groups according to the intervention approach.

Clinical evaluations will include pain assessment using the Numeric Rating Scale (NRS), functional evaluation using the Shoulder Pain and Disability Index (SPADI), and quality of life assessment using the Short Form-36 (SF-36). In addition, shoulder range of motion will be measured goniometrically. Muscle thickness of the supraspinatus and infraspinatus will be assessed using ultrasonography, and shoulder muscle strength will be evaluated using an isokinetic dynamometer.

Assessments will be performed at baseline, 24 hours, 1 month, and 3 months following the intervention. The primary outcome of the study is the change in shoulder muscle strength, while secondary outcomes include pain, functional status, and muscle thickness.

The findings of this study are expected to contribute to the literature by identifying the optimal anatomical approach for suprascapular nerve PRF in the management of chronic shoulder pain.

• PRF of the Suprascapular Nerve (Notch Approach) (Procedure): Under ultrasound guidance, a radiofrequency needle will be positioned adjacent to the suprascapular nerve at the suprascapular notch. Sensory stimulation at 50 Hz and motor stimulation at 2 Hz will be performed to confirm appropriate needle placement. Pulsed radiofrequency will then be applied at 42°C for three cycles of 120 seconds.
• PRF of the Suprascapular Nerve (Midpoint Approach) (Procedure): Under ultrasound guidance, a radiofrequency needle will be positioned adjacent to the suprascapular nerve at the midpoint between the suprascapular notch and the spinoglenoid notch. Sensory stimulation at 50 Hz and motor stimulation at 2 Hz will be performed to confirm appropriate needle placement. Pulsed radiofrequency will then be applied at 42°C for three cycles of 120 seconds.

Primary outcomes

• Isokinetic Shoulder Abduction Peak Torque [Baseline and 3 months]: Isokinetic peak torque of shoulder abduction will be measured using an isokinetic dynamometer (ISOMED 2000). Measurements will be performed to evaluate changes in muscle strength.

Secondary outcomes

• Pain Intensity (NPRS) [Baseline, 24 hours, 1 month, and 3 months]: Pain intensity will be assessed using the Numeric Pain Rating Scale (NPRS), ranging from 0 (no pain) to 10 (worst imaginable pain).
• Shoulder Function (SPADI) [Baseline, 1 month, and 3 months]: Shoulder Pain and Disability Index (SPADI) will be used to assess pain and functional status. SPADI is a validated questionnaire consisting of 13 items with a total score ranging from 0 to 100, where higher scores indicate greater pain and disability (worse outcome).
• Supraspinatus and Infraspinatus Muscle Thickness [Baseline and 3 months]: Muscle thickness will be measured using ultrasonography to evaluate structural changes in the rotator cuff muscles.
• Shoulder Range of Motion (ROM) [Baseline and 3 months]: Shoulder joint range of motion will be measured using a goniometer.
• Quality of Life (SF-36) [Baseline and 3 months]: Health-related quality of life will be assessed using the Short Form-36 (SF-36) questionnaire. SF-36 consists of 8 domains, each scored from 0 to 100, where higher scores indicate better health status (better outcome).

Sex: All, ages: 40 Years to 80 Years

Inclusion Criteria:

* Patients aged between 40 and 80 years
* Patients with chronic shoulder pain lasting longer than 3 months
* Patients diagnosed with rotator cuff-related shoulder pain
* Patients who show at least 50% pain reduction after diagnostic suprascapular nerve block
* Patients who provide written informed consent

Exclusion Criteria:

* Adhesive capsulitis
* Previous shoulder surgery
* Full-thickness rotator cuff tear
* Neurological disorders affecting the shoulder
* Pacemaker
* Coagulopathy or anticoagulant therapy contraindicating intervention
* Infection at the injection site
* Severe systemic disease
* Pregnancy
* Inability to comply with study protocol

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• Jain E, O'Connor IT, Tram JK, Varlotta CA, Fiala KJ, Asaad FS, Chitneni A, Abd-Elsayed A. Radiofrequency ablation for shoulder pain: an updated systematic review. Ann Palliat Med. 2024 Jul;13(4):963-975. doi: 10.21037/apm-23-529. Epub 2024 Jul 4. PMID 38988077
• Tran J, Peng P, Agur A. Evaluation of suprascapular nerve radiofrequency ablation protocols: 3D cadaveric needle placement study. Reg Anesth Pain Med. 2019 Sep 16:rapm-2019-100739. doi: 10.1136/rapm-2019-100739. Online ahead of print. PMID 31527162

• Ayşe Merve Ata, MD, Principal investigator, Ankara City Hospital Bilkent