Medical Division, Defence Services Medical Rehabilitation Centre, Headley Court, Epsom, Surrey KT18 6JN, UK
Sir, I read with interest the paper by Harms et al. [1]. They have attempted to characterize spinal manipulative forces in an ingenious and scientific manner. However, I am concerned about the method of mobilization used on the lumbar spine. Specifically, direct postero-anterior pressure on any spinous process can be painful, especially in thin subjects, and pain may account for some of the spread of force data in grade III and IV mobilizations.
I would like to point out that Harms et al. have looked at one aspect of manipulation, namely mobilization. High-velocity manipulative thrust is also used by professional manual therapists [2, 3] (but rarely in the median sagittal plane), and it would be useful to categorize the force characteristics of such methods scientifically. Often during such procedures, one hears an audible click which is generally attributed to distraction of facet joints, and movement of related soft tissues. Remembering the law of conservation of energy, one would have to include the audible products of manipulation as a component of force measurement.
As yet, we have not been able to characterize the forces applied directly to spinal tissues in the living subject during manipulation, and although useful, the instrumented mobilization couch can only give us a surrogate idea of the forces. In an era in which we need to base our decisions on sound evidence, validated methods of measuring such techniques deserve further study.
References