"Discs Can't Slip!"
Posted: Saturday, January 10, 2009
by Doc Tel Boy
Back Trouble UK
Technically a disc can't "slip."
The term slipped disc is essentially a slang term for a bulging or herniated disc. The name, while dramatic is incorrect as the disc has not slipped. None the less, people who have this condition complain of one thing; a lot of pain!
The causes of a herniated or bulged disc are varied; however factors associated with poor disc health include lifestyle choices such as smoking, lack of regular exercise, and inadequate nutrition. Additionally heavy work, poor posture, daily wear and tear, injury or trauma, and incorrect lifting or twisting causes further stress to the disc.
Fifty percent of people with a disc herniation experience no symptoms whatsoever! Of those that do experience symptoms the most common will be pain in the area of the herniation that may radiate across the hips or into the buttocks. Other people experience numbness or pain radiating down their leg to the ankle or foot. If the herniation is large enough, you may notice weakness with extension of your big toe and you may be unable to walk on your toes or heels.
In severe cases of lumbar disc herniation, you may experience changes in your bowel or bladder function and may have difficulty with sexual function. This is a medical emergency and you need to go to hospital immediately if you are suffering these symptoms.
Back pain is one of the most common and expensive medical conditions in terms of money, lost wages, disability payments, and also in terms of human misery.
The large majority of chronic back pain is due to disk damage. I am using the term disk damage' because disks may not have enough damage to them to be considered to be herniated, but nevertheless cause significant pain, stiffness, muscle spasticity and other symptoms. Disk damage is sometimes referred to as a slipped disk, bulging disk, prolapsed disk, herniated disk, or just a bad back.
Typically, disk damage becomes significant beginning around the age 35 to 45. Disk damage is caused by wear and tear. Rather than having either a bad back, or a strong back, we all have damage to our disks, only the degrees of damage are different. While the onset of symptoms may be sudden, even instantaneous, the damage had been there for years. It tends to become worse over time, although after the disks lose enough fluid, around age 65 to 70, the symptoms often decrease. The damage to the disks still remains, but there is not as much pressure on them, so the are less likely to press on nerves or cause referred symptoms like sciatica or dropfoot. So it affects mostly people in middle age when they are generally at their career and earning peak. It makes people feel old before their time. Doctors and other health care professionals do not like to deal with patients with disk damage. Using mainstream medical techniques, at least, there is no easy cure. Physicians dislike telling a patient who is in severe intermittent or chronic pain that there is little they can do for them, except maybe to send them for physiotherapy or give them painkillers or muscle relaxants. If bad enough they can use surgery. During the 1960s and `70s, spinal fusion was much used, but now we can see the risks versus the benefits more clearly. The benefits are almost never worth the risks.
Standard practice is for physicians to provide clients suffering from low back pain with pain medication, and refer them to a physiotherapy clinic. They probably do not have much faith in the physiotherapists chances of curing the client, but it is all they know to do.
Surreptitiously, they might suggest a chiropractor, or patients may decide that on there own. But these are the most common choices open for them. There are some other treatments such as proprioceptive neuromuscular facilitations, TENS, acupuncture, ultrasound, etc, but all these have limited benefits, provide only temporary relief or have a low success rate. They are focused on making the back problem more bearable, not in curing it.
Before learning how to best treat disk herniation, we must learn more about the disk, and how it is injured. Disk injury can occur in the neck, the cervical spine, but the large majority occurs in the low back, the lumbar spine. Disks are located between the vertebrae. They act as shock absorbers, or pads between the bones of the spine. Most often disk damage occurs in L5-S1, the lowest disc, or L4-L5, the second lowest. The `L' refers to the Lumbar spine, the lower back. `S' refers to the Sacrum, where the spine connects to the back of the pelvis. They are numbered, so L4 is above and L5 is lower down.
If you look at a vertebral disk from above, it is shaped roughly like an oval. You might say that it resembled a doughnut without the hole. It has a liquid core in the centre, so it could be compared to a jelly filled doughnut. Surrounding the liquid core are tough fibrous rings. These rings are layered like an onion or like the annular rings in the cross section of a tree. Above and below each disc is a vertebra, and to the rear is the spinal cord and its branches extending forward and to the sides.
Disk herniation or bulging occurs at the back of the disk, or as we say, posteriorly. At least if a disk were to bulge out in front it would cause few symptoms as the majority of symptoms are caused by the bulge pressing on a nerve branch of the spinal cord. But for reasons we will touch upon later, disk damage is always on the posterior of the disk. In addition, most often, the bulge is on the left side. So usually, sciatica runs down the left leg.
As mentioned, disk injury is caused by wear and tear, rather like osteo-arthritis. Sometimes physicians call disk damage `arthritis of the spine'. The damage is caused by repeated forward flexion of the lower spine--- in other words, bending forward from the waist. The lower back is designed to have a curve to it, as viewed from the side. If you look at the whole spinal column, it has a definite `S'shaped curve in profile. The lumbar curve is the bottom half of the S. When we bend forward from the waist, we flatten out the curve, or even reverse it. When we bend forward we also put pressure on the front part of the disk. This pressure on the front (anterior) of the disc produces the damage to the back (posterior) of the disc. Think of squeezing a tube of toothpaste at one end. The toothpaste is moved back, away from the pressing thumb. Think of squeezing a balloon at one end. It causes the balloon to bulge at the opposite end.
Downward pressure on the front/anterior of the disk is transformed into pressure directed on the back/posterior of the disc. Like the balloon analogy, when a spinal disk is squeezed in the front, it will eventually bulge in the back. A bulging disk will not result from just leaning forward to tie your shoes a single time. But think of how often we find ourselves leaning forward. Most of us spend hours every day leaning forward while sitting at a desk. When we drive we also lean forward in the seat. Sitting and improper posture are the main sources of disc damage. Think of the potential damage done of repeated and constant unbalanced pressure for hours a day, over many years on the fibrous rings of the disc. . Many people, even doctors, think that heavy lifting and carrying is somehow the main source, but it is not so. If you look at most people with disk damage, they probably work at a desk or are truck drivers. This repeated and consistent pressure eventually tears the annular fibres at the back (posterior) of the disk. The central cores of the disk (nucleus pulposa) is liquid, or jelly -like. Certain kinds of cutting tools use liquid under pressure to cut through metal.
Pressure on the nucleus pulposa has the same cutting action, over time. This is the immediate source of disk damage. Lifting heavy objects does put stress on the disk, but this is momentary. Far more serious is damage done through activities we do over a longer period of time, hours a day, over weeks, months and years. The idea that lifting and carrying heavy objects being the main source comes from occasional incidences of bouts of back pain brought on after lifting something heavy. But the idea that lifting a heavy object causing disk herniation in a healthy back is wrong. In those incidences in which some person lifts a heavy object and after has a bout of sciatica or severe back pain, the individual already had disk degeneration. The lifting is only the final straw that broke the camels back (pardon the pun). If they hadn't lifted that particular load, they would have had the same bout of back pain, just weeks or months later.
Even before the disks develop a bulge, the tearing of the fibres of the disk causes symptoms. The innermost layers have no innervation, however, the middle layers do have some, and the outer layers have more nerves. When the tearing reaches the middle layers, messages are sent to the brain to the effect that there is some damage to the lumbar disks. The brain sends messages in return to tighten up the muscles surrounding the damage. So the lower back muscles become rigid in order to act as a kind of splint for the area, just as a broken bone might be splinted. But this protective mechanism becomes more of a problem than a solution. The muscles become tight 24 hours a day. They become what is called `spastic'. This`spasticity' becomes a problem. The muscles are overworked constantly, but under these circumstances the work does not strengthen the muscles but weakens them. They become rigid and frozen, unable to contract or lengthen properly. In addition since they never really move, the body decides that they are not supposed to move, The body's logic is that if something is not a moving part, then it should be strengthened by growing fibrous reinforcement which are called adhesions, and eventually there is calcification within the muscles. The affected lower back muscles begin to feel like leather instead of flesh, and eventually can feel as hard as wood to the therapist.
The loss of flexibility that people notice in their late 20's or 30's is the beginning of this spasticity. As the back muscles become permanently tightened and overworked, they can become painful. The tightness of the soft tissues in the area and the adhesions constrict blood flow, like a pipeline being blocked, causing a build-up of lactic acids and other waste products, and shortages of oxygen and nutrients normally carried into the tissues by the blood. Eventually the torn fibres in the disc cause the liquid core to migrate backwards (posteriorly) the disc bulges like a tire tube with a weak spot. The bulge on the disk moves closer to where the nerve emerges from the spinal cord. This bulge may be a millimetre away from the nerves running out of the spine, but there are still no neurological symptoms like sciatica or severe back pain. This can go on for years, Perhaps the back feels stiff or sore or tired, but nothing that would stop someone from working or doing their normal activities. But then one day the bulge shifts that extra millimetre and presses on the spinal nerve root. It might be during heavy lifting, or it might be when they are doing nothing in particular. Some people just wake up with it in the morning. It seems sudden, but has been building up for years. Suddenly they are in excruciating pain. It may be pain confined to the lower back, or may be in the form of sciatic pain shooting down the leg; it might be in the form of what is called `dropfoot'. Dropfoot is when the muscles on the top of the foot become paralysed so that when they try to walk, their foot won't lift up.
Their foot drags along as they walk, like the character Igor in the Frankenstein movies. If it continues, they might need to get a foot brace. This pain or paralysis generally is bad enough to keep them in bed for a week or two then subsides, at least for awhile. The sciatica and lower back pain comes and goes over the years. Episodes of pain tend to become more severe and last longer over time as more damage is done to the disk. In a number of cases the pain eventually becomes constant. Because it is episodic, the first few times the physician may claim that their treatment cured it or the chiropractor might claim success with his or her manipulations. But really, the pain would have gone away whether it was treated or not, The disk bulge simply shifts off of the nerve root by itself after a time. It will return, but is quiescent for now.
This is a basic outline of the problem. But disk damage does not have to be a life sentence of pain. A physiotherapist in New Zealand named Robin McKenzie stumbled on a highly effective treatment for disk damage back in the 1960's. The McKenzie Technique or Method I have already written various articles on, but is now the standard treatment for disk damage in many countries. In the UK it is very slowly becoming more recognised. Many physiotherapists, chiropractors and physicians have never even heard of it, but more know of it or perform the McKenzie technique than, say, 5 years ago. This is my interpretation of the McKenzie Technique, an attempt to put it into laymen's language.
We know that forward flexion of the lower back puts pressure on the front of the disk, causing damage to the fibres. What McKenzie found is that by doing the opposite, you could press the disk bulge flat and re-centre the liquid core of the disk, thus getting rid of the major symptoms. The opposite of flexion at the waist is called back extension.
The McKenzie Technique is accomplished with a combination of things that act together. Firstly the therapist teaches clients to avoid bending forward from the waist, in other words postural education. He/she educates them how to stand, sit, lie down, and other normal activities without bending forward from the waist. Instead, bending from the hips or knees are substituted. As well as avoiding bending forwards, (s)he teaches people to adopt a posture with a healthy arch to their lower back. It is a small lifestyle change, and a small price for elimination or minimising of backpain.
Secondly there are back orthotics, which help you maintain the arch in the lower back while sitting. Remember that sitting and leaning forward is likely the most common cause for disk damage. People sit at work, sit in their car driving home, and then sit watching TV or playing on the computer. Thirdly, there are exercises to create an exaggerated arch in the back in order to help push the disk bulge flat or push things back into place. Most commonly they involve lying face down and pushing the upper body off the ground with your arms, a sort of back bend as if you were limbo dancing. But in limbo dancing you are on your feet and the upper body is more or less parallel to the ground. In this you are face down and lifting the top half of your body up perpendicular to the ground. As mentioned, it is to create an exaggerated arch in the lower back. I was shown a method, which I used to teach clients.
In it the client is told to lie on their stomach with pillows under the front of the thighs and also under the chest. This allows the client to maintain an extended/arched back position for a longer period of time because the pillows support the position. Pillows are available around the house and allow it to be done daily. Pillows from the chesterfield work well, with two under the thighs and one under the chest being best.
Lastly, there is the hands-on work done by the therapist on a specially designed table. In this, the patient lies face down while the therapist loosens up the back muscles and fascia with a broad handed massage type technique. The therapist also controls the table, which is made to rise up at both ends while the centre of the table remains low. This forces the back to arch. Over a number of treatments, the therapist manages to loosen up the back enough that the patient's back is able to assume a progressively more arched position. These treatments are often painful for the patient, and challenging for the therapist. But a certain amount of pain for a few moments is far preferable to years of chronic pain and disability.
I predict that eventually, the McKenzie Technique will become the standard treatment for disk damage in the UK, but the medical community is slow in making any significant change like this. My estimation is that it will take at least another 10 years.
Terry O'Brien
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Top-level comments on this article: (2 total)Thanks for the clarification I’m sure that those interested in the topic presented will find your article informative and interesting.
Thanks Robert,
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