Position and anatomical landmarks
The techniques for PRF treatment and infiltration of the supra-scapular nerve are identical.
For local infiltration, 2 ml bupivacaine 0.25% with 40 mg corticosteroids in depot is injected.
The patient sits on the edge of the bed with the neck in slighlyt lateral flexion. It is not necessary to use imaging techniques for this procedure. Localisation and treatment using anatomical landmarks are more efficient, less expensive, have less radiation hazard, and give better results.
Figure 1. Anatomy of the shoulder joint, landmarks for PRF treatment and infiltration of the suprascapular nerve.
The anatomy and innervation of the shoulder, with particular attention being given to the supra-scapular nerve and the landmarks for infiltration and PRF treatment, are presented in Figure 1. The spina scapulae is palpated and demarcated from the cranial side.
Figure 2. Insertion site for treatment of the suprascapular nerve.
Across the middle of a line running from the acromion to the medial border of the scapulae, another line is drawn parallel to the cervical spinal column; the lateral angle is then divided into two equal parts with a line and an X (the injection site) being drawn on this line 2.5 cm from the angular point. An SMK 10/5 needle is inserted perpendicular to the skin in all directions until bone contact is made with the scapula in the supraspinatus fossa; this usually occurs at a depth of 5-6.5 cm. The scapular incisure is located at the cranial border of the supraspinatus fossa, known as the superior scapular border (Figure 2). This is the injection site for the suprascapular nerve. Care should be taken not to insert the electrode too far ventrally; there is a small chance of rib contact or lung collapse. The electrode is connected to the generator and with a motor stimulation (2 Hz) of < 0.3 V twitches should be visible in the shoulder girdle. Thereafter, PRF treatment is executed at a frequency of 2 Hz, 20 msec and 45 V lasting four minutes. There is usually immediate improvement with regard to movement and pain in most patients. In some cases, treatment must be repeated after a few weeks.
- The most serious complication after the injection is infection.
- Small subcutaneous bleedings may result in a temporary increase in pain after the injection.
- There is a risk of pneumothorax.