A randomized, double-blind controlled trial study comparing the efficacy of granisetron versus lidocaine injection of trigger points in upper trapezius of patients with Myofascial Pain Syndrome referring to the AJA University Hospital

The effect of topical injections of Granisetron compared with lidocaine on pain trigger points in the upper trapezius muscle, among patients diagnosed with myofascial pain syndrome

A randomized, single-blind, clinical trial with 2 intervention groups including 40 samples in blocks of 4

40 patients referred to Physical medicine and rehabilitation department of 501 Artesh hospital, divided in 2 groups randomly (1 group injection of Granisetron and other group injection of Lidocaine ) then each group evaluated separately using Visual Analog Scale, Neck Disability Index and Neck Pain and disability Scale in first, one month and 3 months later.

Entry requirements: 1. Being at least 18 years old 2. Neck or shoulder pain complaints for at least one month 3. At least one trigger point in the upper trapezius muscle 4. Non pregnant woman 5. No prior disease (severe cystic, spine, spinal canal stenosis) 6. No history of fibromyalgia or rheumatic diseases 7. No prior history of allergy to Granisetron or lidocaine. Exclusion conditions: 1. No patient co-operation or follow up 2. Pain Aggravation (unbearable for the patient)

Single administration of 1cc lidocaine (0.5% concentration) trough injection (Caspian Pharmaceutical Company). Single administration of 1cc Granisetron trough injection (Caspian Pharmaceutical Company)

Visual analogue scale; Neck Disability Index; Neck Pain and Disability Scale.

For random allocating of two groups with the same size of 20 participants (40 patients in total) we used block randomization with different block sizes. The sizes of blocks would be a multiple of 2 and a divisor of 40 (2,4,8). At first, the block sizes were selected randomly. Then, for each block, different permutations for equal group size were determined. Finally, one of the permutations was selected randomly. Random numbers were generated in an independent statistical office and with the help of a computer.

Our study was a double-blind randomized trial. The participants, investigators, and clinicians were unaware of the treatment assignments. The sequence of allocation was concealed from all investigators and participants with sequentially numbered sealed envelopes prepared at the statistical office. The envelopes contained cards with the group assignments type. A nurse who was neither involved in the intervention nor in the assessments opened the envelope and prepared the solutions for injection based on the treatment assignments. The solution was then injected by a physician blinded to its content. All follow-up evaluations were done by a physical therapist blinded to the group assignment.