In an article published in late 2007 in the prestigious Journal of the American Academy of Orthopaedic Surgeons, the often asserted position that whiplash injuries cannot result in chronic pain was evaluated by three reknown spine specialists in an evidence-based analysis. The result: there is no basis for this assertion. In fact, the article shows that a significant number of persons suffering acute neck pain following a motor vehicle collision develop chronic pain that last for years. Further, that a significant number of these patients succumb to partial or total disability. The most common source of the chronic pain: damage to the spinal facet joints.
The facet joints are small joints on each side of a vertebrae that, along with the disc, stabilize the spine and allow bending, twisting and side to side movement. In a rear-end automobile collision, the “facet joints undergo a nonphysiologic pinching motion, with compression posteriorly and distraction anteriorly, usually coupled with shear.” This abnormal stress on the joint can cause damage to the capsular structure around the joint, damage to the articulating structures of the joint itself, and even intra-articular hemorrhage. When such damage occurs pain is transmitted to the brain through a medial branch nerve that innervates the facet joint.
The problem with facet injuries is that they do not show up on x-rays, CAT Scans or MRIs. That is because the injuries involve microscopic damage to tiny features within the joint that are not usually observable in these studies. Often, this leads physicians to the conclusion that there is no structural damage to the spine, and that the pain must be deriving from the surrounding “soft tissues.” This then leads to the conclusion that “soft tissue” injuries ordinarily resolve in weeks or months, not years.
In the past several years, many advancements have been made in the field of pain management that have furthered our understanding of the role that the facet joints have in chronic whiplash pain. Through injection procedures called “medial branch blocks,” and then through specific deadening of the medial branch nerve through a procedure called “radiofrequency ablation,” medicine has been able to isolate the facet from other spinal structures to determine if the joint is the source of the pain. The beauty of these new techniques is that only the pain that can come from the facet joint is intercepted. This not only confirms the involvement of the facet joint, it also verifies the legitimacy of the patient’s complaint.
In this recent article, entitled Chronic Whiplash and Whiplash-Associated Disorders: An Evidence-Based Approach, (Amer Acad Orthop Surg 2007; 15:596-606), the authors review the medical literature and published data concerning chronic whiplash pain. The review reveals that 15% to 40% of patients with acute neck pain following a motor vehicle collision develop chronic pain, and that 5% to 7% become permanently partially or totally disabled. The most common source of chronic whiplash neck pain – the facet joint (49% to 54%).
Over the years, it has been our experience that the potential of a facet injury to explain chronic whiplash neck pain is often overlooked by the medical community. Patients that continue to suffer chronic pain months and years after a motor vehicle collision should discuss the possibility of such an injury with their physicians. A referral to a competent pain management specialist may quickly confirm the existence of a facet based injury, and lead to good management of this chronic pain syndrome.