Efficacy of Interferential Laser Therapy in Shoulder Pain (PI070046)

The purpose of this study is to determine the advantages of the interferential laser therapy in shoulder pain reduction compared with the conventional low level laser therapy modality.

The spatiotemporal superposition of two independent and opposite beams of laser generates a constructive interference pattern that increases the therapeutic effects in the irradiated tissue. Patients diagnosed of shoulder pain from different musculoskeletal disorders will received conventional or interferential laser therapy. This is a comparative, randomized and double - blind clinical study. Two identical equipments of near infrared laser therapy will be used. Number of sessions: 15. Frequency of the sessions: daily. Irradiation technique: manual, contact and punctual.Pain will be evaluated by visual analog scale (VAS) at rest and during analytical shoulder movements (abduction, adduction, internal rotation, external rotation, flexion, extension) and by means of a pain and disability index (SPADI). Evaluations will take place at pre and post treatment.

Interference Laser Therapy., Device Brand Name: Laser Sys. Stim 540(Mettler Electronics)., SN: 105XLS147 (first laser) and 105XLS148 (second laser).

Two GaAlAs laser (810 nm, 100mW)were used. In the interferential laser treatment, two probes were simultaneously applied. In the conventional laser group, only one probe was switched on. Laser was applied at five points over the pain area. The laser emission mode was continuous with an energy dose of 6 joules per point and session, a power density of 1.09 w/cm2 and an irradiation time per point of 60 s. The average output power was 100 mW and the total energy dose delivered in a patient session was 30 J. Every treatment was along 15 sessions. Hence, the accumulated energy delivered on the whole was 450 Joules for the conventional group of patients (using one beam) and 900 Joules for the interferential one (using two beams).

Pain will be evaluated by visual analog scale (VAS) at rest and during analytical shoulder movements.

Inclusion Criteria: Acute or chronic pain from musculoskeletal origin Age between 18 and 70 years Exclusion Criteria: Brachial plexus palsy Neurological diseases Pacemakers Shoulder pain from cervical pathology Osteosynthesis material Fibromyalgia

Montes-Molina R, Madronero-Agreda MA, Romojaro-Rodriguez AB, Gallego-Mendez V, Prados-Cabiedas C, Marques-Lucas C, Perez-Ferreiro M, Martinez-Ruiz F. Efficacy of interferential low-level laser therapy using two independent sources in the treatment of knee pain. Photomed Laser Surg. 2009 Jun;27(3):467-71. doi: 10.1089/pho.2008.2315.

Montes-Molina R, Prieto-Baquero A, Martinez-Rodriguez ME, Romojaro-Rodriguez AB, Gallego-Mendez V, Martinez-Ruiz F. Interferential laser therapy in the treatment of shoulder pain and disability from musculoskeletal pathologies: a randomised comparative study. Physiotherapy. 2012 Jun;98(2):143-50. doi: 10.1016/j.physio.2011.02.007. Epub 2011 May 28.