Neural Response of Cervical Facet Joint Capsule to Stretch: A Study of Whiplash Pain Mechanism

• DOI: 10.4271/2005-22-0003
• Publication Date: 2018-11-21T18:34:53Z
• Authors: Ying Lu; Chaoyang Chen; Srinivasu Kallakuri; Ajit Patwardhan; John M. Cavanaugh
• Keywords: Strain (injury); Capsule; Joint capsule; Facet (psychology)

Cervical facet joints are implicated as a major source of pain after whiplash injury. The purpose this study was to investigate the proposed capsule strain injury mechanism using neurophysiologic methods. Strain thresholds, threshold distribution, saturation strains and afterdischarge responses neural receptors were characterized in vivo. Goat C5-C6 joint capsules used identify characterize response controlled uniaxial stretch by recording C6 dorsal rootlet nerve discharge. stretched at 0.5 mm/sec series tests with 2 mm increments until ruptured. Ninety-two identified units responsive physiologic or noxious while 28 silent receptors. Among 50 units, 42 showed low thresholds 10.2+/-4.6% 8 had high 47.2+/-9.6%. Further, 35 low-threshold displayed discharge various (44.2+/-16.7%). A significant finding that twelve exhibited for greater than 30 sec release 36.6+/-12.5% strains, longer-lasting (greater 4 min) higher (39.0+/-14.4%) difference (p = 0.019) strains. Two high-threshold afterdischarges min 50.3+/-5.9% 57.7+/-10.6% respectively. In addition, spatial distribution demonstrated on gap more strain-sensitive, significantly lower compared rostral caudal regions. No observed medial-lateral direction. When reported experienced (35-60%) subfailure (35-67%), substantially whereas within range. Thus, appear signal proprioception High likely nociception (pain sensation) may contribute persistent pain.