A Feasibility Study to Assess Vibration and Sound From Zygapophyseal Joints During Motion Before and After Spinal Manipulation

Abstract

Objective: This feasibility study used novel accelerometry (vibration) and microphone (sound) methods to assess crepitus originating from the lumbar spine before and after side-posture spinal manipulative therapy (SMT).

Methods: This study included 5 healthy and 5 low back pain (LBP) participants. Nine accelerometers and 1 specialized directional microphone were applied to the lumbar region, allowing assessment of crepitus. Each participant underwent full lumbar ranges of motion (ROM), bilateral lumbar SMT, and repeated full ROM. After full ROMs the participants received side-posture lumbar SMT on both sides by a licensed doctor of chiropractic. Accelerometer and microphone recordings were made during all pre- and post-SMT ROMs. Primary outcome was a descriptive report of crepitus prevalence (average number of crepitus events/participant). Participants were also divided into 3 age groups for comparisons (18-25, 26-45, and 46-65 years).

Results: Overall, crepitus prevalence decreased pre-post SMT (average pre = 1.4 crepitus/participant vs post = 0.9). Prevalence progressively increased from the youngest to oldest age groups (pre-SMT = 0.0, 1.67, and 2.0, respectively; and post-SMT = 0.5, 0.83, and 1.5). Prevalence was higher in LBP participants compared with healthy (pre-SMT-LBP = 2.0, vs pre-SMT-healthy = 0.8; post-SMT-LBP = 1.0 vs post-SMT-healthy = 0.8), even though healthy participants were older than LBP participants (40.8 years vs 27.8 years); accounting for age: pre-SMT-LBP = 2.0 vs pre-SMT-healthy = 0.0; post-SMT-LBP = 1.0 vs post-SMT-healthy = 0.3.

Conclusions: Our findings indicated that a larger study is feasible. Other findings included that crepitus prevalence increased with age, was higher in participants with LBP than in healthy participants, and overall decreased after SMT. This study indicated that crepitus assessment using accelerometers has the potential of being an outcome measure or biomarker for assessing spinal joint (facet/zygapophyseal joint) function during movement and the effects of LBP treatments (eg, SMT) on zygapophyseal joint function.

Keywords: Facet Joint; Spinal Manipulation; Zygapophyseal Joint.

Copyright © 2017. Published by Elsevier Inc.

Figures

Figure 1

Flowchart showing a model of putative beneficial anatomical/biomechanical effects of spinal manipulation, including the theoretical relationships of crepitus and cavitation to the model.

Figure 2

Placement of accelerometers and specialized directional microphone; A = subject with the 9 accelerometers and microphone taped in place for recording; B = close-up of one of the accelerometers; C = close-up of the microphone; D = illustration showing placement of 9 accelerometers (solid circles) and the microphone. See supplemental electronic material for color figure.

Figure 3

Accelerometer and microphone recordings were taken during 6 ranges of motion, including: flexion (A), extension, right and left (B) rotation, and right and left (C) lateral flexion. See supplemental electronic material for color figure.

Figure 4

Spinal manipulation was performed with the accelerometers and microphone in place. Ultrasound of the right L3/4 Z joint is shown being conducted simultaneously for another component of the project that will be reported separately.

Figure 5

Example of crepitus detected by accelerometers and microphone (see supplemental electronic material for color figure). Fig. 5A is a LabView oscilloscope recording of crepitus taken during left lateral flexion in a 55 year old male. The flat baseline can be seen at the far left, followed by the sharp response of several accelerometers and the distinct, broad waveform of the microphone. Fig. 5B is an expanded (by ~100X) timeline of the same crepitus. Again, notice that the accelerometers are at their individual baselines at the far left, followed by a dramatic simultaneous shift from the baseline of several accelerometers. The L2 (red) and L3 (green) accelerometers leave their baselines first, followed by L4 (gray) and the left accelerometer (dark blue). This was crepitus at the Left L2/3 Z joint. The microphone (light blue) has a very broad wave pattern that is best seen with the more contracted timeline (Fig. 5A). This distinct wave pattern from the microphone was rare. Fig. 5C is a recording of an artifact of the L1 and S2 accelerometers, which may have been caused by the subject’s gown bumping the accelerometers.

Figure 6

Figs. 6A and B report crepitus taken during motions before spinal manipulation (Pre-SMT) and Figs. 6C and D report crepitus taken during motions after spinal manipulation (Post-SMT). Figs. 6A and C report the individual zygapophyseal (Z) joints from which crepitus were recorded during full ranges of motion. Joints from which crepitus was recorded during more than one movement or multiple times during the same movement were counted only once in 6A and C. In 6B and D, if crepitus was recorded during multiple movements of the same joint, or multiple times during the same movement, each incidence of crepitus was counted. Results for healthy subjects are reported in bold typeface and those for low back pain (LBP) subjects are reported in italics. See supplemental electronic material for color figure.

Figure 7

Distribution of cavitation during ranges of motion. See supplemental electronic material for color figure.