This is the result of a consensus among international experts that endorses its use and, at the same time, emphasises the need for more robust scientific evidence to consolidate its application in clinical practice. The work was coordinated by Ennio Lubrano, from the University of Molise, and Luis Sequeira de Medeiros, from the Centro Hospitalar Universitario in Lisbon, Portugal, and the results were published in the scientific journal Pain Therapy (https://www.springer.com/journal/40122).
Types of musculoskeletal pain and the use of heat therapy
Musculoskeletal conditions are the leading contributor to disability worldwide, with low back pain being the single leading cause of disability in 160 countries. Musculoskeletal conditions significantly limit mobility and dexterity, leading to early retirement from work, lower levels of well-being and reduced ability to participate in society. According to the Global Burden of Diseases, in 2019 approximately 1.71 billion people live with musculoskeletal conditions worldwide.
Heat therapy, which consists in applying an external source of heat to a specific area of the body to increase tissue temperature, is one of the oldest non-pharmacological treatments in medicine.
Heat therapy has long been used for thousands of years for therapeutic purposes in musculoskeletal disorders with proven efficacy and safety. Moreover, it can have a positive impact on quality of life, physical, psychological, and socio-economic aspects of musculoskeletal injuries/disorders-related pain.
Heat therapy is recommended as non-invasive and non-pharmacological treatment by American guidelines in the treatment of low back pain and osteoarthritis. Indeed in some clinical studies, it was demonstrated to be more effective than non-steroidal anti-inflammatory drugs (NSAIDs) and paracetamol.
Consensus among experts reached with the Delphi method
However, no clear indications on the use of heat therapy in musculoskeletal pain are available to date. For this reason, the Delphi method was applied. It allows a group of experts to give their answers on a given topic with the aim of obtaining the most comprehensive and shared opinion, called consensus.
The survey on the use of heat therapy in musculoskeletal pain involved, anonymously, 116 specialists, including rheumatologists, sports medicine specialists, physiotherapists, family doctors and physiatrists. They expressed their opinion on 54 statements concerning aspects such as the mechanism of action of heat, the type of pain that benefits the most from heat therapy, the timing and mode of treatment, and safety. They had to express how much they agreed with the statements by giving a score on a scale of one to five. Consensus on a particular statement required 66% of the specialists to agree.
The benefits of heat therapy according to experts
The experts reached a consensus on 78% of the statements. In particular, they strongly agreed on the effect of heat on flexibility, increased blood flow and tissue metabolism, and its contribution to the healing process. The increased blood flow delivers more oxygen and nutrients to the damaged tissues, promoting metabolic activity, thus resulting in increased strength and muscle activity and improved mobility in everyday life. Also with regard to the mechanism of action, experts strongly agreed that the activation of temperature-sensitive nerve endings, called thermoreceptors, is responsible for the reduced feeling of pain.
Experts also strongly agreed on the appropriateness of heat therapy in non-specific low back pain and chronic pain, whereas it is not indicated in acute inflammatory joint pain. Mild to moderate consensus was obtained for the treatment of tendinitis, muscle soreness, osteoarthritis, and mechanical pain.
Furthermore, experts agreed that heat therapy provides short-term pain relief and can reduce the need for analgesics and that it can help in the long term, reducing disability in low back pain, preventing it from worsening and improving daily living activities.
Finally, experts agreed on the safety profile of heat therapy, which is well tolerated by patients when applied to intact skin.
Lubrano E. et al. An international multidisciplinary Delphi-based Consensus on heat therapy in musculoskeletal pain. Pain Ther (2022) doi: 10.1007/s40122-022-00419-4