Superficial Cervical Plexus Block for Neck and Shoulder Pain Due to Levator Scapulae Syndrome: a Randomized, Double Blind Clinical Trial

Patients are randomly divided into two equal groups using the computer-based sealed envelope technique. Group I (Block) will receive superficial cervical plexus block and group II (Placebo) will receive placebo. The physician, patient and data collector are all blind to the patients' assigned group.

Demographic data including gender, age, BMI and American Society of Anesthesiologists (ASA) physical status will be noted at the initial visit. Moreover, patients' medical history, pain history, characteristics and type of pain, as well as previous treatment are collected for each patient. In addition, side effects, pain scores and analgesic consumption will be recorded after performing the block.

Patients will receive 14 daily charts to record daily pain scores, symptoms and the use of analgesics. Patients will be told to take their medications as usual. They will be contacted via phone calls to ensure that they are recording information in the charts.

Pain is assessed using the visual analogue scale (VAS). Patients with score <4 are given 500 mg paracetamol with a maximum of 6 tables per day, or ketoprofen 100 mg tablet to a maximum of 3 tables per 24 hours. Patients with a score>4 are given tramadol hydrochloride 100 mg tablet to a maximum of 3 tablets per day.

Superficial cervical plexus block technique A nerve stimulator is used to guide the superficial cervical block. The nerve stimulator needle is first passed over the skin after aseptic preparation from the distal to proximal part of the posterior border of the sternocleidomastoid. Upon contraction of the levator scapulae, a mark is placed and the skin is infiltrated with 1 ml lidocaine 1%. A 22-G, 2.5 cm nerve stimulator needle is subsequently advanced through the skin by 0.5-1 cm depending on patient's weight while passing 5-8.5 mA current at 1 Hz. Then, the stimulating current is reduced to 0.5-0.6 mA while maintaining muscle contraction. At this point, 3-5 ml of the anesthetic mixture is injected. Each 10 ml of the anesthetic mixture contains: 3ml lidocaine 2%, 3 ml lidocaine 2% with epinephrine 1:200,000, 3 ml bupivacaine 0.5% and 1 ml clonidine 150µg/ml. Group II will receive an equivalent volume of normal saline.