Analysis of Crepitus in Human Subjects

Overview

Chiropractic adjustment has been shown to gap certain joints in the spine, thereby improving mobility in individuals with decreased movement capabilities. During normal motion, joints in the spine produce sounds and vibrations called crepitus. The purpose of this study is to assess how this crepitus may be used as an indicator for joint degeneration in healthy human subjects and those with low back pain, and if chiropractic adjusting causes change in this crepitus. The investigators hypothesize that change in crepitus after adjustment may be a useful indication of changes in joint mobility and joint stiffness.

Objective: This is an expansion of the initial study "Analysis of Crepitus in Human Subjects" to assess the feasibility of simultaneously recording zygapophyseal (Z) joint crepitus using piezoelectric accelerometers and Z joint motion using diagnostic ultrasound (US), and qualitatively assess the US images with particular focus on images taken of Z joints exhibiting crepitus. Like the original study (n=12), the results of a recently developed automated method (AM) is compared with two human observers in the analysis of recordings of human lumbar zygapophyseal (Z) joint crepitus. The recordings will be taken during ranges of motion performed before and after lumbar side-posture spinal manipulation (SMT). Methods: Six (6) healthy and 6 low back pain subjects will participate in the study. Using clinical study procedures developed previously, subjects will be given an initial phone screen before being scheduled for a clinical study appointment. At the appointment, subjects will undergo the informed consent process, and those consenting will be further screened and examined by the Research Clinician who will use the inclusion/exclusion criteria to determine eligibility for the study. Eligible subjects will be enrolled and scheduled for an accelerometry visit. At the accelerometry visit, 11 accelerometers will be applied to the lumbar region, allowing assessment of Z joint crepitus. US imaging of the right L4/L5 Z joint will be included. Each subject will undergo full flexion and full extension (ROM) while recordings are made from the accelerometers. Subjects will then undergo bilateral lumbar SMT, and immediately thereafter will undergo repeated ROM while recordings are made. Two human observers and the AM, blinded to the results of one another, will then assess the recordings to identify Z joints from which crepitus originated. The primary outcomes will be: 1) weighted kappa inter-rater reliability statistic comparing AM and the 2 human observers in identifying Z joint crepitus, and 2) ANOVA test statistic comparing time to complete the crepitus analysis by the AM and human observers. Hypotheses: 1) The automated method will be reliable, agreeing with the human observers' analysis. 2) The automated method will be significantly more time efficient than the analyses made by the human observers. Application: The investigators believe that this program will improve the efficiency of identifying the site of Z joint crepitus, thereby advancing the line of investigation designed to use crepitus as a biomarker of spinal joint dysfunction.