Principles of managing pain arising from the spine
Low Back PainLow back pain is a common condition. Estimates of the prevalence of low back pain vary considerably between studies - up to 33% for point prevalence, 65% for 1- year prevalence, and 84% for lifetime prevalence. Prevalence does not vary with age. It is commonly thought that most episodes of low back pain settle spontaneously. This is unlikely to be the case. 75% patients consulting their General Practitioner for an episode of low back pain will continue to be symptomatic one year later (Croft et al. BMJ 1998;316;1356-1359). The management of low back pain is complex. The management of low back pain is primarily conservative (non-operative). Physiotherapy should be the mainstay of treatment. Patients may be referred to see a spinal surgeon after conservative measures have failed ( physiotherapy, osteopathy, chiropractic, drug therapy or time). It is often the “end of the road” for a patient with pain. Surgical management of low back pain can only be entertained when the source of the pain can be pinpointed. There are several steps in diagnosing where low back pain originates.
Clinical history. The primary source of this information is the patient’s symptoms - the history if the condition. A careful history taking is invaluable and can often give a very firm idea of the pain source. It helps to exclude serious underlying conditions. The majority of patients with back pain fit into a recognisable pattern which guides us towards a likely diagnosis.
Physical examination. The physical examination is the second source of information. The spine is very difficult to feel - it is a very deep structure. Information can be gleaned from how the spine looks, moves and feels and these can be focussed using more specific tests. A neurological examination is nearly always required and gives information about how the nerves are working.
Imaging. Modern imaging techniques add further valuable information. Plain X-rays have limited value in the assessment of spinal conditions since the availability of Magnetic Resonance Imaging (MRI), but is required in some cases. MRI scans give excellent imaging of the spine and allow us to see the individual nerves in the spine, the discs, facet joints, the bone marrow, inflammation, nerve compression and a host of other abnormalities. The addition of MRI has forwarded the management of spinal conditions more than any other development.
- Diagnostic injections. Diagnostic procedures are performed to fine tune the diagnosis. If the pain source is not readily identifiable from the above methods, or the pattern is not clear, invasive diagnostic procedures are extremely useful. These usually involve placement of a needle under x-ray guidance to the area suspected of being painful (a spinal nerve, facet joint or disc) followed by injection of a small volume of local anaesthetic with or without an anti-inflammatory steroid. If there is good, concordant reproduction of pain at the time of injection and the pain resolves to a significant extent then it is likely that the injected site is responsible for the pain. Although primarily thought of as diagnostic, spinal injections also have a significant therapeutic effect and can ease pain in both the short and medium term.
Serious but rare conditions affecting the spine can present with low back pain. These include spinal infections and spinal tumours. They are rarely seen but important to recognise. Patients presenting with certain symptoms are investigated with this in mind. It is important your GP sees and assesses your back pain should it persist. The more worrying pain is that which is constant and does not improve with rest, occurs at night stopping sleep, associated with being unwell (fever, rigors), associated with steroid use. This is not a complete list - it is meant as a guide.
Neck pain is common and usually as a result of the natural ageing process of the spine. With time, spinal intervertebral discs degenerate and loose height, the facet joints at the back of the spine become arthritic. The process is commonly referred to as "spondylosis". Pain can originate from the facet joints, the discs, compression on nerves or as a result of general dysfunction of the cervical spine. Non-surgical management in the form of physiotherapy is recommended as the mainstay of treatment. Self management can complement physiotherapy treatment and a useful guide is Robin McKenzie's book "Treat your own neck". Other forms of treatment such as osteopathy, chiropractic therapy or acupuncture may provide relief for the stiff painful neck also. Manipulation should be avoided in any case where there are neurological symptoms or signs consistent with spinal cord compression.
Sciatica is pain in the low back, thigh and lower leg as a result of irritation or compression of the spinal nerves. The most common cause of this is a herniated lumbar disc. It can be a very disabling but, usually, self-limiting condition. The natural history of sciatica is that it will settle on its own without treatment in 85% of cases. Those cases failing to improve significantly within 6 weeks of onset can be treated with injection techniques (selective nerve root blocks) or surgery (microdiscectomy). There is evidence that early surgery has very good results and allows earlier return to full activity, but is not routinely performed before 6 weeks of continuing symptoms. The Spinal Outcomes Research Trial shows the four year results patients with a herniated lumbar disc when they undergo surgery compared to the results for patients who do not undergo surgery.
There are two clinical scenarios that require urgent decompressive surgery.
• Cauda equina syndrome is a specific condition where the spinal nerves supplying the muscles (sphincters) that control bowel and bladder function are compressed and stop working. This is considered a surgical emergency; surgery is undertaken in these cases as soon as possible. If you suffer from new onset bowel or bladder dysfunction at the onset or during an episode of sciatica, you must inform the your on-call GP as soon as possible or attend the Accident and Emergency department. Bowel/bladder dysfunction may be permanent if left untreated.
• Painful foot-drop. In this scenario, a herniated disc traps one of the spinal nerves and gives not only severe pain but also compete loss of power to the muscles that bring the foot into dorsiflexion (pulls the foot off the floor). Patients undergoing surgery for this condition have a better long-term results than patients managed non-operatively.
This is effectively sciatica in the arm. It is usually as a result of a spinal nerve being compressed as it exits from the spine. The compression can be from bone, disc or a combination of the two. The natural history is that with time the pain settles in the vast majority of patients within 6 weeks. Physiotherapy alters the natural history little in the early stages. If nature fails to resolve the condition within a reasonable time, an MRI scan should be performed in order to confirm the diagnosis. A selective nerve block is usually considered at this stage. The injection is performed under local anaesthetic and delivers an anti-inflammatory steroid to the painful nerve at the point where it exits the neck. Surgery is performed for cases that fail to improve with conservative measures and nerve root blocks. Surgery should be considered earlier if there is significant neurological deficit or any risk to the spinal cord. Surgery usually involves removal of the intervertebral disc followed by total disc replacement or fusion of the motion segment involved.