Measurement of variations in lumbar zygapophyseal joint intracapsular pressure: a pilot study

A pilot study using four subjects was conducted to investigate a proposed method of measuring 'in vivo' lumbar zygapophyseal intracapsular pressures. The authors were interested in establishing whether a resting pressure could be measured, and to observe pressure changes within the lumbar zygapophyseal capsules with fluid injection and with a range of active and passive movements including manipulative techniques. The results indicated that the apparatus could effectively measure intracapsular pressure changes on injection and lumbar movements. Significant pressure changes with specific localized manipulative therapy techniques were demonstrated. A resting intra-capsular pressure reading was not obtainable. Further controlled studies using this approach could provide valuable anatomical and clinical knowledge for the future.