Parklodge Medical Centre
Back & Joint Pain
Read on for Explanations & Advice on the following conditions
|Disc Prolapse/ Disc Protrusion|
The phrases ‘slipped disc’ or ‘sciatica’ used to be commonly used terms in describing backpain.
However discs are not the only cause of backpain. Strained or weak muscles, strained ligaments or stiff spinal joints can also become sources of pain. The architectural complexity of the spine is what makes assessing and treating backpain so challenging (and to Chartered Physiotherapists, so interesting and rewarding!). It also means that caution is necessary in discussing your backpain with others. Your backpain may not be the same as that of the next person you meet and may require a different approach to get better. If your pain comes from different structures in the back it is like comparing apples and oranges, both are fruit but are entirely different.
Both terms ‘slipped disc’ and ‘sciatica’ have fallen out of use in medical circles, for very good reasons (see below).
Our understanding of what how a disc functions and what goes wrong has improved with the advent of MRI scans and modern surgical techniques. Up until a decade ago the only way of investigating discs was via standard x-rays. However discs are radio-opaque, showing up as blank spaces in the spine between vertebrae. So from a spine x-ray we can only infer what is going on in a disc rather than is the case when an x-ray confirms a broken bone. MRIs, using a different technology, can show in immense detail the bones, internal structure of discs, whether nerves are being compressed and more.
This has greatly contributed to improved medical and clinical understanding of disc damage. A short explanation of the anatomy or architecture of the spine will assist your understanding of what can go wrong and how serious (or not) different types of disc problems can be.
Discs are found between every two vertebrae (spinal bones), so we have 22 discs from the neck to lower back. The structure and size of each disc varies as you go down the spine, with the largest discs (and most prone to damage) found in the low back just below the waistline.
A lower back or lumbar disc is about 5mm thick. It comprises outer fibrous rings surrounding an inner pulpy semi-liquid core. The fibrous rings are solidly attached to the bottom and top of the vertebrae above and below. This attachment anchors each disc in place, ensuring that the rings which form the outer component of the disc absolutely cannot ‘slip’ forwards, backwards or in any direction.
This is why the term ‘slipped disc’ has fallen out of medical use, as it does not in any way accurately describe what has gone wrong in the back. Other things happen to discs but ‘slipping’ is not one of them.
So what does happen? The key to the function of the disc is the inner pulpy centre, called the nucleus fibrosis. The nucleus acts like a soft deformable ball- bearing assisting spinal movement in all directions. The bony vertebrae above and below, coupled with fibrous rings surrounding the nucleus means that the pulpy centre is always held under pressure. Think of the rings as a tube of toothpaste and the nucleus as the paste within.
Disc Damage: degenerative (cumulative, ageing related) / acute tear
As we age and cumulatively use our spines more and more, the disc begins to show signs of wear. With age, repeated or awkward movements of the spine the outer rings begin to yield to the internal pressure from the nucleus. The rings develop microscopic damage in the form of tiny cracks or fissures. This is the first stage of disc trauma or disc disease. Gradually or occasionally suddenly, the cracks become bigger until a full tear of one, several or all rings occur.
Acute disc damage / Disc Prolapse/ Protrusion
Once the outer fibrous ring is breached the pulpy core squeezes into the crack. The tearing process of the outer rings on its own causes local inflammation in the spine which often presents as aching backpain, usually in the immediate area of the spine.
The pulpy core pushing into the torn ring further causes pain. Very often this aching pain will settle by itself in a few days. If the tear is big the quality of the pain may be more intense but again the pain will be felt mainly locally.
If backpain is accompanied by pain going down the leg (front of thigh, side of back of thigh, into the calf, even spreading to the foot), this symptom suggests that a nerve has become affected by the physical presence of disc material which has seeped out from the ring. The symptom of pain in the leg, coming from the back is known generically as ‘sciatica’
Sciatica is the term applied to leg pain emanating from the back. The term is widely used and refers to pressure or compression of the Sciatic Nerve. Nerves coming from the lowest levels of the moveable spine join up either side becoming a thickest nerve trunk in the body (the width and girth of an index finger or thumb in adults). This nerve trunk is called the Sciatic Nerve. ANY and all problems affecting the Sciatic Nerve are labelled ‘Sciatica’.
However the nerve can be compressed by several different structures around and outside the spine, each of which brings on similar symptoms of varying degree in the leg. Accurate clinical diagnosis of the faulty structure is vital from a therapeutic standpoint, as different structures compress this major nerve in different manners. Each may require a different type of therapeutic intervention to take off the compression and restore the nerve to full health.
If the process of crack development occurs very gradually eventually the outer rings begin to buckle a bit, losing height from 5mm to 4 or 3mm. So instead of standing up straight the rings look and behave like deflated car tyres. The loss of disc height is clearly seen on a simple x-ray and infers that some form of disc disease has already occurred. In medical terms this is known as a ‘bulging’ disc and is surprisingly common. Normative MRI studies on populations in each decade of adulthood have shown that cumulative age related disc trauma or wearing occurs increasingly in every episode of life. 20% of 20 year-olds have wear signs observed on MRI, 30% of 30 year olds, 40% of 40 year olds, up to 70% of 70 year olds... One interesting fact to emerge from this normative research is that presence of disc signs on MRI does not necessarily correlate with presence of backpain, stiffness, loss of spinal motion and other back symptoms. Some people who participated in this extensive study had very severe backpain and sciatica without much objective or observable evidence on MRI of significant damage, others had lots of evidence of wear and damage but reported relatively little pain or problems. However, n the main there was a reasonably accurate correlation between damage seen on MRI and type and severity of symptoms.
Conservative Management of Backpain:
The vast majority of backpain responds well to conservative (i.e. non-surgical) management. Physiotherapy, with a multitude of knowledge, clinical skills and techniques can assist in resolving most types of back pain.
Conservative management commences with taking a careful history. Issues addressed include when the pain came on, whether acutely or gradually over time, how the pain and related spinal movement dysfunction impacts on the person’s lifestyle, what aggravates symptoms, how symptoms ease of their own accord and numerous other factors. The physiotherapist then performs a careful clinical assessment using validated tests (tests which have been proven by scientific research to provide valid information and results). Synthesis of the history of the presenting backpain and its clinical signs allows formation of a specific structural diagnosis where the actual faults are identified.
Most backpain is mechanical to some extent. Mechanical issues can be treated with
• manual therapy
• therapeutic exercise addressing both flexibility and muscle strength
• pain relieving techniques (manual therapy, electrotherapy, acupuncture, soft tissue release, etc.)
• advice on overcoming the current presentation and preventing re-occurrence
• long term maintenance to prevent relapse
Mechanical backpain, often referred to as ‘simple’ backpain in the medical literature usually responds well to mechanical intervention and pharmacology
(over the counter or G.P prescribed).
Most back surgeons operate on strict criteria before offering surgery. Back surgery is one of the many areas of medicine that has moved on greatly with the advent of accurate diagnosis (MRI scanning being the Gold Standard).
Though not without risk, microscopic back surgery for disc prolapse plays a very important role for a small category of patients with severe back or leg pain who have not responded to conservative management. Most disc surgery now is done as by keyhole or arthroscopic technique where very fine instruments are introduced into the spinal canal to pinch off the piece of prolapsed disc material, relieving compression on the nerve. Often only requiring a short hospital stay and a four – sic week recovery and rest from work, most patients recover fully after surgery, though it is vital to regain fully rehabilitate the back and regain strength in order to make a full recovery.