By Ashley O'Rourke PT, DPT, ATC, LAT
Back pain is extremely common. Bulging discs and herniated discs are just as common. People often think that disc issues are a permanent diagnosis or a lifelong sentence for pain. They’re not!
Herniated Discs most often occur in the lower lumbar spine. In many cases, they cause no symptoms and require no treatment. On the other hand, others with herniated discs may experience pain, weakness, burning or tingling in their back or down their legs/arms due to the bulge pressing on the nerve.
Disc Bulges & Herniations:
Disc bulges and herniations come and go with about 80% resolving without medical intervention. They occur in both symptomatic and asymptomatic people and are a natural part of aging. The prevalence of seeing a disc herniation on MRI in PAINFREE people increases with age. For instance: disc herniations occur in only about 30% of 20 year olds who have no symptoms, but in around 84% of 80 year olds who have no symptoms. (Nakashima; Brinjikji)
You can think of your discs like jelly donuts. Years of poor posture (rounded back/forward head while sitting), repetitive bending forward or an acute injury such as lifting something heavy with a rounded back can cause the "jelly" [nucleus pulposas inside the disc] to shoot out the back of the “doughnut” [disc] as if you had squeezed the doughnut on one side. When this happens, the “jelly” can bulge out far enough that it puts pressure on the nerve causing back pain and/or symptoms down leg or arm.
Therefore, you must work into the opposite direction- extension. Extension exercises are those that involve strengthening the posterior chain (glutes, hamstrings and back muscles) or arching the neck/back backward. Think "superman" exercise. As you focus on extension based exercises, you are working to push that "jelly back into the doughnut”. This seems simple enough, but why then do people end up with pain/symptoms off and on throughout their entire life related to the same discs?
The answer is incomplete healing. Often times, people will do their extension exercises at PT, but when they get back to their home or work, they fall back into bad habits- sitting for hours in flexion. This “undoes” everything the patient just did at PT. Consider this paper cut analogy:
If you sustain a cut on your knuckle and continue to bend your finger, what will happen? The scab will continue to rip off, the wound will reopen and it will cause the injury to take longer and longer to heal. The same thing happens with discs. As you perform your extension exercises, you are working to "push the jelly back into the disc". This, along with good posture (avoiding flexion or bending forward) gives the body an environment to heal. The disc then begins to scar down which keeps the "jelly" inside much like the scab on you finger keeps your skin together and blood inside. While this is exactly what we want to happen, if you then start bending your spine into flexion- much like bending your finger- that scab will rip off, the wound will re-open and you will continue the cycle of pain.
Discs will heal on their own just like everything else in our body, but we must give it the ENVIRONMENT to do so. This is the one concept that separates those who feel relief within a few weeks from those who have chronic neck/back or sciatic pain that comes and goes throughout their entire life. If you give the disc an environment to heal and scar down just like a cut on your finger (by avoiding flexion), then you’ll soon be able to bend forward painfree just as your finger can.
Sciatic Pain is a symptom, NOT a diagnosis.
Sciatica refers to the irritation of the sciatic nerve that may cause numbness, tingling, burning or electric-like pain down the leg. The source of the irritation is often stemming from the back or hip and includes bulging or herniated discs that can put pressure on the nerve.
Sciatic pain can be debilitating and scary, but can frequently be resolved through positional exercises. It is important to remember:
1. Progress slowly (significant changes often do not occur overnight. Slow and steady improvement is normal)
2. Don’t be afraid to move (It is human instinct to want to avoid a movement that elicits pain. While this is true for some cases, in others, this can actually make the patient feel worse. In this situation, pain that is centralized to the low back/spine is OK. If the exercise elicits pain down the leg then the movement should be avoided)
3. Pain is complex (this can include fear avoidance, psychosomatic factors, sleep habits, physical/mental stress and diet just to name a few)
4. Discs HEAL!
What is Directional Preference:
When a patient's pain symptoms can be made better or worse by adopting various, differentiated, active positions, it is said that a patient has a directional preference of movement for treatment. Identifying this directional preference through mechanical means is called the McKenzie Method (often referred to as Mechanical Diagnosis and Therapy or MDT). The patient's "directional preference" is the direction of movement that causes pain symptoms to move more centrally (toward midline which is the spine of the back or neck), as opposed to shooting down the arm or leg and into the hands/feet.
For those who have pain or nerve symptoms down the back of their leg while bending forward, sitting, driving etc and prefer to stand, walk or lie on their stomachs- you likely have an extension bias. Those who have increased pain and symptoms with walking, standing and lying on their stomach, but a reduction in pain with sitting or bending forward, you are likely to have what's called a flexion bias.
Most importantly, we must NOT stop moving, but move into our 'directional preference' while avoiding the opposite direction which ilicits pain. This will not be forever, but is important to do in the beginning stages until tissue capacity allows us to eventually reintroduce the aggravating direction, building tissue tolerance and overall work capacity.
What is Centralization?
Centralization describes a phenomenon where pain originating from the spine and referred distally (into legs/arms), moves or retreats back towards the midline of the spine in response to repeated movements or guided positioning. The pain then often diminishes or is eliminated entirely.
This phenomenon occurs through performing exercises working into our directional preference. By performing these exercises, the pain should begin to centralize (meaning that the pain decreases down the leg or arm and moves toward the back or neck). During this process, the pain in the back may increase. This can be scary for a person who arrived with only leg pain and now all of the sudden has a new onset of back pain. It is important to know that this is NORMAL and a GOOD sign that the plan of care is correct. As the pain moves closer to the back you can think of it as the nerve being less irritated. The center of the low back is the last place the pain must travel before disappearing completely. On the other hand, if you perform the extension exercises and you feel increased pain down the leg or arm then you should stop the exercise and speak with your PT.
Disc herniations are a normal part of life and the aging process. Sometimes they are relevant to pain, but often times they are not. Chances are if you have one, you will be just fine and physical therapy geared toward your directional preference will help you get there! Remember, discs DON'T slip.