Study design: Sixty-four asymptomatic participants, ranging in age from 22 to 49 years, volunteered to act as patients for the study. Twenty-eight different clinicians performed thoracic and lumbar spinal manipulative procedures. The range of clinical experience was 1 to 43 years.
Objectives: The purpose of this study is to first locate the joints that produce an audible sound in response to manipulation (cavitation) during spinal manipulative procedures so that the accuracy and specificity of manipulation can be assessed.
Summary of background data: Clinicians utilizing spinal manipulative therapy (SMT) claim to be very specific and accurate with the delivery of their dynamic thrust. It has been suggested that the clinical success of SMT is dependent on the accurate delivery of that therapy to the target spinal joints.
Methods: Asymptomatic participants received SMT to either the thoracic or lumbar regions of their spine. Accelerometers were secured to the skin over the spinal column, and the relative time at which each accelerometer detected the vibration from the cavitation associated with the SMT was used to calculate the source of the vibration. The site of cavitation was then compared with the target location.
Results: For lumbar SMT, the average error from target of 124 cavitations in lumbar procedures was 5.29 cm (at least one vertebra away from target), with a range of 0 to 14 cm. Of these cavitations, 57 were deemed to be accurate and 67 were deemed to be inaccurate. The average error from target of 54 cavitations in the thoracic spine was 3.5 cm, with a range of 0 to 9.5 cm. Of these cavitations, 29 were deemed to be accurate and 25 were deemed to be inaccurate. In most cases, individual manipulative procedures were associated with multiple cavitations ranging from 2 to 6.
Conclusions: In the lumbar spine, SMT was accurate about half the time. However, because most procedures were associated with multiple cavitations, in most cases, at least one cavitation emanated from the target joints. In the thoracic spine, SMT appears to be more accurate.