Fusion a Pain in the Neck (or Back) for Injured Workers – Adjacent Segment Disorder and Adjacent Segment Pathology

The vast majority of work injuries in Pennsylvania heal with conservative treatment, allowing the injured worker to return both to work, as well as to activities of normal life.  However, there are certainly the more serious injuries, where more invasive medical treatment is required.

Often the more invasive treatment options entail surgery.  When we are talking about work injuries to the neck and back, the procedures we usually see are laminectomy, microdiscectomy and traditional lumbar fusion.  For a description of each of these, and more information regarding these procedures, check out this post from Penn Medicine.  For our purposes today, we are looking at the traditional lumbar fusion.  As explained in the Penn Medicine article:

Traditional spinal fusions are used to treat instability of the spine, scoliosis, severe degeneration of the discs, or a combination of these issues.  A fusion involves using bone from the patient’s body to fuse one vertebrae to another.  Often, metal screws (pedicle screws) are placed into the vertebrae to assist with the fusion process.”

Once an injured worker has a fusion to the cervical or lumbar spine, by definition, there is less movement in the areas affected.  This can place a greater stress on the levels of the neck or back above and/or below the levels that have been fused.  Adjacent Segment Degeneration (ASD) or Adjacent Segment Pathology (ASP) is the name of the condition which addresses this stress on the levels surrounding the fusion.  There have been many studies in this area, though there seems to be no consensus regarding the exact rates or progression of the disorder.

Why is this important in a PA workers’ compensation case?  Other than the obvious issues regarding the health and disability of the injured worker, there is also the impact of this condition in the context of an Impairment Rating Evaluation (IRE)We have discussed the IRE process here many times.

Before a workers’ comp insurance carrier can obtain an IRE, and change the status of benefits from total to partial, there must be a finding that the injured worker is at “Maximum Medical Improvement,” (MMI).  We have discussed this definition previously on this Blog, quoting from the American Medical Association’s Guides to the Evaluation of Permanent Impairment:

MMI represents a point in time in the recovery process after an injury when further formal medical or surgical intervention cannot be expected to improve the underlying impairment. Therefore, MMI is not predicated on the elimination of symptoms and/or subjective complaints. Also, MMI can be determined if recovery has reached the stage where symptoms can be expected to remain stable with the passage of time, or can be managed with palliative measures that do not alter the underlying impairment substantially, within medical probability…”

So, if the injured worker had a cervical or lumbar fusion, and ASD or ASP may cause damage to the levels surrounding the fusion, causing further disability and the need for additional medical treatment, then is the injured worker really at MMI?  Would this still be a “stable” condition upon which MMI can be based?  There is no case law to cite here, but just food for thought.