Far Lateral Herniated Discs

spinal stenosis

Far lateral herniated discs present unique diagnostic problems for doctors and patients alike, since many go unnoticed as the actual source of pain. Far lateral herniations exist outside the spinal canal and are therefore not often concentrated upon during diagnostic testing, such as MRI scanning. In many cases, the effects of the far lateral protrusion are not seen on the imaged locations, often contributing to a misdiagnosed herniated disc condition.

Far lateral herniations are also called lateral herniated discs, but this can get confusing, due to another type of disc protrusion known as a posterolateral bulging disc. Another common name for a far lateral protrusion is extraforaminal disc protrusion, since the herniation exists outside the neuroforaminal opening. This nomenclature can get very complicated and confusing for a layman, so it is vital that every patient performs diligent research needed to thoroughly understand their diagnostic conclusion.

Most herniations can cause pain through either central spinal stenosis or neuroforaminal stenosis. The later topic is what I will focus on in this article relating to far lateral herniated discs. Foraminal stenosis is described as a narrowing of the opening through which the spinal nerve roots must pass as they exit the spinal canal. Usually, when a bulgingd disc encroaches upon the foraminal space, it has the potential to affect the nerve exiting at the same level as the affected disc. Therefore, a typical posterolateral or paramedial herniated disc located at L4/L5 would possibly affect the L5 nerve root as it tries to pass through the foraminal opening. In the case of a far lateral herniation, the bulging portion of the disc exists on the other side of the foraminal space, and can possibly impinge upon or compress the nerve root above the affected level. Once again, in a herniation located at L4/L5, this would mean effects would be possible on the L4 nerve root, instead of the L5.

Since clinical symptomatic correlation is crucial to diagnosing pain due to herniated discs, the far lateral disc bulge can present some challenges. Usually, as noted above, the nerve would be the same level as the herniation in the vast majority of patients. If symptoms do not correlate by location, then a diagnostic enigma might exist. The herniation has been clearly seen, but symptoms do not match the clinical expectation. When it comes to far lateral herniations, this is the case, almost every time... When I see this clinical profile exist, I always consider the chance that the herniation may be far lateral in nature, and would usually recommend that it be studied from enough angles to get a good read on this possibility.

It must be noted that most herniations, far lateral or not, do not cause any pain or related neurological symptoms. In short, herniated discs are the most common of all back pain scapegoats. However, there are certainly herniations which can and do cause pain and even serious health emergencies, such as cauda equina syndrome.

In closing, I have a recommendation to neurologists and orthopedists who are dealing with disc pain sufferers... Always consider that when a patient has a clearly defined and correct symptomology for a particular compressive neuropathy condition and demonstrates a sizeable herniation at the level below, but no structural explanation at the same level, the possibility for far lateral causation may exist. In these cases, be sure to visualize the herniation from the angles needed to determine if it is indeed creating extraforaminal nerve compression. This is a major step in minimizing the chances for misdiagnosing your patients.