Feasibility Study of Ultrasound Measurements on the Human Lumbar Spine

Abstract

This study is a part of a research project that aims to measure the variation in the intervertebral distance of patients that are subjected to lumbar flexion-distraction chiropractic manipulation. The purpose of this research project is to evaluate the feasibility of using a B-scan image generated by a customized ultrasonic design to measure the distance between the adjacent lumbar vertebrae Previous research using the same customized ultrasonic design was done and it was found that the reproducibility of the measurement expressed in terms of the coefficient of variation for measurements of the artificial model was found to be better than 0.1% (0.013 mm standard error), whereas for measurements of human subjects it was better than 1% (0.1 mm standard error). The excellent results obtained from the test conducted on the artificial model verify the reliability of the testing instrumentation and methodology. Before this system is routinely used in clinical situations it needs to undergo further testing process. This system was tested to measure the distance between the lumbar vertebrae of the artificial spine model by scanning the transverse process instead of the spinous process. This experimentation showed us a few drawbacks and certain limitations of using this ultrasonic design equipment. As a consequence we employed the commercially available high-end ultrasonic device, Philips HDI 5000. Several experiments were conducted on the artificial spine model using this ultrasound machine, such as measuring the distance between the transverse process of the lumbar vertebrae, measuring the depth of the transverse process from the surface of the gelatin solution and measuring the width of each transverse process. Experiments were also made to measure the width of each spinous process of the lumbar vertebrae and these measurements were then compared with the measurements obtained from our customized ultrasound system and also with the physical measurements from the vernier calipers. Measurements obtained from the two ultrasound systems and vernier calipers were very close. Further tests were conducted on the customized ultrasound system to measure the distance between the lumbar vertebrae (L1, L2 and L3) by imaging the spinous process in a traction conditioned situation. To simulate the traction in the artificial spine, 1 mm rings were used and were placed in-between the vertebral body and the distance was measured. The distance between the lumbar vertebrae was increased by 1 mm for each set of experiments. The results obtained showed that the custom-built ultrasonic system can be used to measure the distance between the lumbar vertebrae by imaging the spinous process in a traction condition. However, a commercially available sophisticated system is needed if the distance between the lumbar vertebrae by imaging the transverse process.