Mechanical diagnosis and therapy

Robin McKenzie (1931 - 2013), physiotherapist in New Zealand, developed a simple but practical classification of back and neck complaints in the fifties. The basis of the classification is how the complaints respond to postures and movements: aggravation, improvement, or without consequences. Once a complaint has been classified, it can be treated according to protocols: Mechanical Diagnosis and Therapy (MDT, also known as McKenzie method).

One of the striking points here is that as much as possible is chosen for exercises, and as little as possible for intervention by the therapist himself with mobilisations, manipulations or otherwise. The classification he made consists of:

a- Posture syndrome

Complaints arise by stretching the band apparatus from the back due to bad, usually sagging posture. The syndrome can be recognized by the presence of local pain that is not constantly present, only occurring after a part of the back has been in the extreme position for some time. Improvement occurs when this posture changes, and there is no pain during movement. In examination, nothing special is found besides a bad posture.

b- Dysfunction syndrome

Pain is caused by stretching of shortened bands or other tissues. This shortening may have been caused by formation of scar tissue on the basis of a previous damage, or long-term inactivity. The syndrome is characterized by the fact that the movement that triggers pain is also limited by the shortened structure. The phenomenon can be called up again and again. The pain is locally present, not constant, and often improves through activity.

c- Derangement or discogenic syndrome

This syndrome has a number of subclassifications depending on the location of the pain, the possible pain-posture of the back, and the possible involvement of a leg. The syndrome is characterized by the fact that pains can quickly worsen and improve through specific movements and postures. The derangement syndrome is often associated with lesions in the intervertebral disc (discus intervertebalis), including hernias. That is why it is also called discogenic syndrome. But clear scientific evidence is still lacking.

d- Rest group

Although this group does not officially belong to the MDT classification, it is of practical importance. The complaints can not be placed on the basis of their characteristics in one of the three previous ones, and therefore can not be treated with according to the MDT principles.


The classification has to do directly with the type of treatment that is being set. The posture syndrome is obviously treated with posture correction. The dysfunction syndrome is treated by 'stretching' the shortened tissue with exercises. The derangement syndrome is treated with exercises that directly improve the symptoms. Attention is also given to prevention in the treatments. Postural correction often plays a role in this. In addition specific exercises and instructions can be given. Because the emphasis in the treatments is mainly on exercises, the method is very suitable for self-treatment. With this, the responsibility of the complaints is returned to the patient and he/she can become more independent of a doctor or therapist.


In the literature, a limited degree of effectiveness is measured with low back pain. This is slightly lower for chronic low back pain. My experience in practice for musculoskeletal medicine is that it can be a very effective method, provided that the individual examination provides a clear indication.


McKenzie RA, May S. The Lumbar Spine. Mechanical Diagnosis and Therapy. (Vol. 1 and 2) Spinal Publications, Waikanae, New Zealand; 2nd Edition, 2003.
McKenzie RA, May S. The Cervical and Thoracic Spine. Mechanical Diagnosis and Therapy. (Vol. 1 and 2) Spinal Publications, Waikanae, New Zealand ; 2nd Edition, 2006.

Machado LA et al. The McKenzie method for low back pain: a systematic review of the literature with a meta-analysis approach. Spine (Phila Pa 1976). 2006 Apr 20;31(9):E254-62.