McKenzie method

The McKenzie method is a technique primarily used in physical therapy. It was developed in the late 1950s by New Zealand physiotherapist Robin McKenzie. In 1981 he launched the concept which he called "Mechanical Diagnosis and Therapy (MDT)" – a system encompassing assessment, diagnosis and treatment for the spine and extremities. MDT categorises patients' complaints not on an anatomical basis,  but subgroups them by the clinical presentation of patients.

McKenzie exercises involve spinal extension exercises, as opposed to Williams flexion exercises, which involve lumbar flexion exercises.

Effectiveness
There is only weak evidence for the effectiveness of the method's use for treating lower back pain. A 2019 systematic review found that there was evidence that it could reduce chronic lower back pain in the short term, and enhance function in the longer term, but that most studies of the treatment had methodological flaws, such as small sample sizes and a lack of blinding.

Compared to other treatments, the McKenzie method is not better at treating acute pain and disability for people with lower back pain. It may be better than some other approaches for chronic lower back pain, but this evidence for this is insufficient to recommend the method.

Exercises targeting midline strengthening, as used in the McKenzie method, are no more helpful for lower back pain than conventional flexion and extension exercises.

More recently in patients with chronic LBP, there is moderate-to high-quality evidence that MDT is superior to other rehabilitation interventions for reducing pain and disability; however, this depends on the type of intervention being compared to MDT. In patients with chronic lower back pain, pain measures showed that the McKenzie method is a successful treatment to decrease pain in the short term, while the disability measures determined that the McKenzie method is better in enhancing function in the long term. However, in acute LBP, this method has not shown a significant reduction of symptoms nor disability.

History
In 1956, McKenzie was treating a patient experiencing pain. The patient lay down on McKenzie's treatment table, and after bending backward for five minutes, reported an improvement in their symptoms. This led McKenzie to experiment with specific movement patterns to treat chronic lower back pain and bring about the movement of pain towards the spine, which he called "centralisation". He later developed a classification system to categorise spinal pain problems, and published books on the topic, including Treat Your Own Back (1980).

The McKenzie method was commonly used worldwide in the late 2000s in diagnosis and treatment of low back pain,   and peripheral joint complaints. The International MDT Research Foundation, based in the United States, funds research to demonstrate the effectiveness and scope of action of the McKenzie method.

Centralisation
The McKenzie method employs the principle that exercises that encourage disc centralization should be promoted, and exercises that encourage disc peripheralization should be avoided. Centralisation occurs when pain symptoms centered away from the mid-line of the spine migrate towards it. This migration of pain symptoms to the centre of the lower back is considered a sign of progress in the McKenzie method. Extension exercises are sometimes referred to as McKenzie exercises for this reason. According to the McKenzie method, movements and exercises that produce centralisation are beneficial, whereas movements that move pain away from the spinal mid-line are detrimental.