Vibration Diagnostic Probe for Discogenic Pain Due to a Fissure in an Annulus Fibrosus

Abstract

Discogenic pain is the most common cause of chronic low back pain, accounting for 39% of causes. One possible diagnostic method to determine the cause of discogenic pain is provocative discography. However, this method is not available to patients with severe fissures due to degenerative disc disease. In this paper, we present a diagnostic probe in which plastic optical fiber (POF), which is located in a hole in the flexible tube of the probe, can be steered to the vicinity of fissures in the annulus fibrosus. Then, a linear motor placed inside the grip generates a minute axial vibration of the POF tip, which irritates the tiny pain nerves located near fissures. The intensity of the pain thus generated is used as a guideline to determine the level of discogenic disease. The frequency and amplitude of the vibration discography ranged from 2.5 Hz to 5.7 Hz and 1.5 mm to 3.4 mm, respectively. The applicability of the designed probe was successfully confirmed by testing the modified intradiscal microprobe in an ex vivo animal experiment.