Characterized by shooting, burning or an electric shock-type pain that radiates down the leg, sciatica has been described by some people as the bane of their existence. In addition to being debilitating, sciatica is widespread with as many as 40% of people experiencing it during their lifetimes.
Sciatica has a myriad of causes and is often wrought with diagnostic issues. For example, if you went to five providers, you could receive five different diagnoses, each receiving unique interventions.
Thankfully, there is a feature of sciatica that can help sort out this diagnostic confusion. Present in up to 80% of people with acute symptoms and 50% of those with long-standing symptoms, it is a feature that can be consistently assessed and is a reliable indicator upon which to base treatment.
This feature is called centralization, which refers to the lasting abolishment of radiating symptoms in response to therapeutic loading strategies. As it relates to sciatica, symptoms would be those that radiate down the leg, and the loading strategies would consist of movements and positions of the lumbar spine.
Take someone with sciatica, whose pain radiates from their low back to their foot. As a result of moving or positioning their spine in a specific direction, the pain only radiates to their right thigh. After more movements in that direction, the pain is now felt as far as their right hip, and then only in their low back. Essentially, their pain centralized from their foot to their back before it was fully abolished.
Centralization is discovered through a unique assessment performed by a provider with adequate training in the McKenzie Method. By having a patient complete a variety of movements in a standardized manner, the clinician is looking for symptoms to centralize in response to a single direction of testing.
When someone is a centralizer, their treatment is the movement or position that elicits the centralization response. Sometimes centralization occurs rapidly and sometimes slowly, but it is almost always associated with an excellent prognosis.
In several studies, patients scheduled to undergo spinal surgery for sciatica were assessed for centralization. In those whom it was detected, nearly all became candidates for non-surgical care. And even though centralization was discovered just prior to surgery, it could have been detected much earlier with the proper assessment.
Clues to centralization can be discovered in a patient’s history. For example, it’s not uncommon for someone’s symptoms to centralize with walking and standing and travel farther down their leg with sitting and bending. Information like that may indicate which direction will likely elicit centralization.
Despite its everyday use in patients with sciatica, diagnostic imaging cannot determine if a patient is a centralizer. This was depicted in a study of 100 patients with sciatica, 51 who were centralizers and 49 who were not. In this patient population, it was discovered that MRI findings such as disc herniations were as common in centralizers as non-centralizers. Because the prognosis is so favorable in centralizers, the findings from that study prompted the authors to conclude that MRIs generally aren’t necessary for patients whose pain is centralizing.
Even though the knowledge of centralization has existed for decades, most centralizers are never discovered. As a result, these patients are routinely escalated to care they do not need, up to and including surgery. Unfortunately, that happens far too often in clinics where patients with sciatica seek care.
Dr. Jordan Duncan is from Kitsap County and writes a monthly online health column for Kitsap News Group. He is the owner of Silverdale Sport & Spine.