Acute herniated disc often leads to nerve trapping and sciatica (pain in your leg). However, not all sciatica is caused by herniated disc, and not all herniated discs cause sciatica. Moreover, during recovery from a herniated disc with associated sciatica, there is a period during which there is no longer any leg pain but the disc is not fully healed. Precautions should continue to be taken over this period to reduce the likelihood of relapse. We are developing a new, Internet software system, CALBA (Computer-Assisted Low Back Assessment), to help distinguish herniated disc from other forms of sciatica and low back pain. CALBA will also distinguish different stages of recovery from herniated disc and on this basis provide advice on precautions, therapeutic exercises and yoga postures.
There are many types of low back pain. Herniated disc (‘slipped disc’) is one of the most common. Herniated disc often heals spontaneously but over 10 percent of cases progress to long-term chronic low back pain and sometimes require surgery. Various activities – including certain remedial exercises and yoga postures – can exacerbate herniated disc. Early detection and appropriate management can enhance the prospects of recovery.
Anatomy, physiology and pathology
When a disc herniates, its outer ring of tough cartilage bulges and breaks, and the inner core, composed of a thick gel, squeezes out through the gap. This can impinge on a nerve root, causing pain, numbness and/or weakness. A herniated disc in the lower spine can trap a root of the sciatic nerve, causing sciatica, a pain shooting along a clearly-defined track down the back of the leg to the foot. It may be accompanied by numbness and muscle weakness.
View of two lumbar vertebrae, with the disc between them. The disc consists of an outer ring of very strong cartilage (annulus fibrosus) and an inner core of thick gel (nucleus pulposus). The discs provide flexibility to the spine and act as shock absorbers: when pressure is exerted on the spine, the discs bulge out, like a bicycle tyre when you ride on it.
A normal disc has a continuous ring of the annulus around its nucleus. In contrast a herniated disc has a rift in the annulus, through which part of the nucleus protrudes. The disc protrusion may impinge on the root of a nerve going from the spine to another part of the body, as shown in this cross section through a herniated disc. Trapping of the nerve root causes shooting pain along the path of that nerve, numbness at the nerve endings and weakness in muscles served by that nerve.
Herniated discs often heal spontaneously, given favourable conditions. The bulge contracts and gradually hardens, sealing the break in the ring of cartilage (like scar tissue in a wound).
The shooting pain and other symptoms disappear, when the bulge has retracted far enough to cease disturbing the nerve root. A more localised pain in the region of the disc usually persists for a time, often accompanied by a diffuse pain in the buttock and back of the thigh. This also can disappear, leaving the back pain free, if the healing goes to completion.
It is useful to distinguish five phases in the healing process:
1. Acute Phase: Severe sciatic pain, curtailing most activities except lying on your back. In its first episode this often lasts only a few hours or days. If it persists more than four weeks, there is a danger that it will damage the nerves and official medical guidelines recommend referral to a specialist.
2. Early Recovery Phase: The sciatica is intermittent and becomes progressively less frequent and less severe. This phase usually lasts a few days or weeks.
3. Middle Recovery Phase: The sciatica disappears, leaving pain in the lower back, accompanied sometimes by diffuse pain in the buttock and back of the thigh. This is known as ‘referred pain’ and is not due to trapping of the sciatic nerve. This phase can last a few weeks or months.
4. Late Recovery Phase: All pain has gone but the healing is not yet complete. There is no definitive evidence as to how long this phase lasts but we recommend allowing at least six months for it to reach completion.
5. Remission: The healing process has successfully completed and normal activities can be resumed.
A relapse can occur throughout the healing process but the risk progressively diminishes as the disc strengthens. In the Early Recovery Phase even gentle movements can bring on the sciatic pain, while in the Middle Recovery Phase many normal activities can be resumed with care. In the Late Recovery Phase there is a temptation to resume even strong activities, because the pain has gone, but this is risky because the disc is still at heightened risk of herniation.
On its first occurrence, a herniation is often small and can heal successfully if given the right conditions. With each successive recurrence, the break in the disk can become more established, so that repair becomes more difficult and takes longer. It is important to take care even during the Late Recovery Phase, when you are tempted to ‘overdo it’ because there is no pain to warn you of the risk.
We recommend you to be careful for at least six months from the time when the pain has ceased. After that you can resume practically all your normal activities, provided you take care and feel no pain or discomfort. Some people who have had a herniated disc report a feeling of vulnerability in the spine when they over-challenge it. This can be a valuable warning signal to be careful.
In our experience healing of a herniated disc can be aided by lifestyle changes, coupled with therapeutic exercises.
Our policy is to reduce as much as possible those activities, which unduly stress the disc, so as to allow healing to take place without relapse. Pain reminds you to do this during the initial acute phase, and also during the following period when the shooting pain recurs with activities that strain the disc. But as the healing progresses, the disc becomes more resilient and causes less pain. There comes a time when all pain has ceased but the disc is still at risk. You should be careful during this period not fully to resume normal activities until healing is completed. We recommend continuing to be careful for at least six months after the pain has completely disappeared, gradually and carefully resuming your full range of activities. Activities which challenge discs include:
• Bending forwards or sideways
• Vacuum cleaning
• Carrying heavy weights
• Long sitting in certain positions
• Long driving
• Sports involving unilateral actions, e.g. tennis, squash, golf, cricket
• Violent sports, e.g. football
Sitting is worse for a herniated disc than standing, especially when slumping. So avoid sitting in easy chairs where your back is rounded. Both at home and at work, use chairs that encourage your lower back to be concave. At home, lying in a prone position can be useful when you are reading, talking or watching TV.
There are various systems of therapeutic exercise for low back pain, including those of physiotherapy, Pilates and yoga. Whichever system you use, it is important to take the precautions outlined above, if you have a herniated disc. We focus here on yoga therapy.
An ordinary yoga class can seriously worsen a herniated disc, because it includes forward bends, side bends and other postures that place pressure on the discs. In contrast yoga therapy tailored for herniated discs is safe and beneficial. Yoga can help the healing process in the following ways:
• Gently mobilising joints – thus promoting repair and maintenance
• Relaxing tense muscles – thus enhancing restorative blood flow to damaged tissues and washing away pain-causing substances from the affected area
• Strengthening core muscles, and improving muscle control – thus improving posture and helping protect the spine
• Heightening body awareness and reducing fear – thus facilitating identification of body positions that are pain-free and devising of ways avoid (or modify) positions that cause pain
Various different selections of yoga practices can be used as therapy for people with herniated disc. We use a sequence designed by Professor D. Dongaonkar, a distinguished orthopaedic surgeon, who also introduced us to the assessment procedure, from which CALBA emerged. The Dongaonkar Sequence is particularly good for people with herniated disc because it uses exercises which are mainly in supine and prone positions, thus taking weight off the disks.
Further information on identification or,and care for,the different stages of recovery from low back pain available on request.