The term “Genomic” when used in describing hereditary spine disorders” is an important descriptive term now being used in modern molecular biology and genetics as a means of describing the entirety of an organism’s hereditary information not just the genes (which contain the coding sequences of DNA). The “genome” includes both the genes and the non-coding DNA and RNA which have sometimes been referred to in the past as “junk DNA” but are now known to have a important role in heredity.
In spine the term “congenital spine disorders” has typically been used in the past to identify the more apparent and better known structural abnormalities such as scoliosis and spondylolisthesis. In fact, the expression “scoliosis/ deformity” per se has come to represent a completely separate discipline of orthopedic spine surgery.
“Genomic spine disorders” is a term intended to describe more hidden, general, and diffuse abnormalities of the spine which are only now really being appreciated. These conditions are typified by inborn errors of metabolism as well as more congenital abnormalities such as multilevel endplate deformities of which Juvenile Discogenic Disease (JDD) is an example. It is clear that all of these entities have some commonality but that determination will have to await the next step in biotechnical science relating to the further elucidation of the human genome. Unfortunately, at this time, the clues to the presence of these commonly seen congenital disorders is in the hands of the more astute clinicians. Simple good history taking is often the first step to appreciating spine disorders appearing frequently in family groups (but only when they are looked for).
The first publication specifically addressing the subject of a radiographically identifiable genomic spine disorder, Juvenile Discogenic Disease, appeared in the journal Spine in 1994. This entity was “discovered” because of the radiographic appreciation of certain characteristic spine endplate deformities frequently associated with advanced degenerative changes. Although most attention has been focused on the lumbar spine it is now appreciated that these changes involve the cervical and thoracic spines as well.
While we bide our time waiting for better genetic testing the diagnosis of these genomic spine disorders will depend on accurately interpreting imaging studies such as MRI (although many of these abnormalities are evident on plain x-rays). It is sad, but true, that very few radiologists, who read and report on MRIs, today are presently familiar with the literature on genomic spine disorders and typically then do not report this essential information to the physicians ordering spine imaging studies. When they do pick it up, however, the physician (or the surgeon) reading the report often has no idea as to what the term means in regard to patient care. Part of this challenge is beginning to better inform primary care physicians.
Why does this sad state of affairs exist? The most persuasive evidence is in the following facts:
- 50% of individuals presenting to a physician with back pain have an identifiable genomic spine disorder which is typically amenable to non-surgical spine care.
- After psychiatric, psychologic, and drug-related costs back pain represents the single highest cost in our present health care system.
- More spine fusions are performed in the United States each year than in any other country in the world. The majority of these are performed in patients to treat low back pain, often as a primary therapy after physical therapy or chiropractic care.
- The early identification and subsequent preventive care of genomic spine disorders may very well represent the single greatest saving in future health care expenditures in the United States.
- More specific genetic analysis of DNA will be the single most important medical advance of the next century.
From a radiographic point of view the most discernable genomic spine disorder is that which has been labeled “juvenile discogenic disease.” The reason for this is the presence of characteristic endplate deformities associated with the advanced degenerative changes throughout the spine.
When Is Disc Degeneration A Disease?
The degeneration of the intervertebral disc is something which we all experience throughout our lives. It is something which is affected by heredity, the environment, as well as insult and injury in addition to the process of aging. The process of cell division is called mitosis. When mitosis gets out of hand and causes disability and incapacitation it is considered a disease. The name of this disease is “cancer.” The same can be true for the process of disc degeneration.
Why was the term “disease” used in the description of Juvenile Discogenic Disease? Well, the prototype for this line of thinking began with:
Holger Werfel Scheuermann (1877-1960), who was a Danish orthopedic surgeon who first described the entity “Scheuermann’s Disease”, referring to the presence of disabling back pain caused by a juvenile spine kyphosis. Scheuermann correctly attributed this “disease” to vertebral endplate deformities which he believed were due to ossification failures. In fact, he was the first clinician to identify a true “genomic spine disorder”.
The term “juvenile” in discogenic disease” was used because these abnormalities are present in juveniles and relate to congenital abnormalities of the spine, endplate, and disc often producing disability from pain as well in addition to progressive neurologic impairment.
One of the Editor’s pet peeves has been the incorrect spelling of the word “disc.” “Disc” is a biologic term while “disk” is a technical term (i.e. computer disk). Just because Medicare decided to spell it incorrectly the entire medical establishment has gone along with this. Unfortunately, the dictum: “them that’s got the gold make the rules” was applied once more.