Managing lower back pain in primary care
Back pain is a very common condition throughout the world, with about 80 percent of adults experiencing low back pain at some point in their lifetime. It is also a common cause of workers missing work. Roshini Claire Anthony spoke with Adjunct Associate Professor Gamaliel Tan, head and senior orthopaedic consultant at Ng Teng Fong Hospital in Singapore, on how GPs can help diagnose and treat this condition.
At the orthopaedic clinic at Ng Teng Fong General Hospital, we see about 500 spine-related patients per month (almost 15 percent of cases in our orthopaedic department). This does not include inpatient admissions for spine-related conditions which number about 100 per month.
Lower back pain can be categorized into three types based on duration: acute, subacute and chronic. Acute back pain lasts up to 4 weeks, subacute back pain ranges between 4 and 12 weeks, and chronic back pain lasts longer than 12 weeks. Back pain can vary from a dull, constant, aching pain to a sudden, sharp pain that can leave the patient incapacitated.
The causes of lower back pain are varied (Table 1). The most common cause is muscular strain.
Assessment of lower back pain
The history should include history of trauma/injury to the back, precipitating and relieving factors, location of pain (back or lower limbs), walking distance before pain stops them (functional assessment), and neurological deficits (foot drop, numbness of lower limbs or perianal region).
Doctors should look out for red flags which can signal a potential surgical emergency which needs referral to the emergency department (Table 2).
Physical examination should cover gait (eg, unsteady gait, antalgic gait, foot drop with high stepping gait), range of motion of spine, palpation to locate point of tenderness, power/motor testing of the lower limbs (using the ASIA score), sensation of the lower limbs, special tests such as straight leg raise to test for sciatic nerve tension, palpation of the pulses to exclude vascular cause of leg pain and range of motion of the hip to exclude hip pathology.
A lumbar spine X-ray should be used to assess for lumbar spine alignment and exclude fractures or spondylolisthesis. Look for any lytic lesions in the pedicles (“winking owl” sign). Magnetic resonance imaging (MRI) of the lumbar spine can assess for nerve root compression, disc degeneration, disc herniation, spinal stenosis, tumour, infections, and fractures, while a computer tomography (CT) scan of the lumbar spine can assess for fractures.
Unlike screening for chronic diseases like diabetes and hypertension, there is no strong evidence for routine screening for lower back pain. Most cases of lower back pain are episodic in nature and do not need lifelong follow-up.
Challenges in diagnosis
The challenge is to not miss clinically significant problems. Advise the patient to return if symptoms worsen or neurological deficits occur. Educate patients on the possibility of cauda equina and advise them to go to the emergency department if they develop symptoms such as perianal anaesthesia or acute retention of urine. Eventually an MRI lumbar scan will be required for cases that are not getting better or have a neurological deficit, together with a spine consultation.
Managing lower back pain
Conservative management should be considered first. For a diagnosis of acute or chronic back strain of musculoskeletal origin, a short cause of analgesics as per the analgesic ladder is recommended. Patients will also benefit from a short course of physiotherapy for lower back pain. During the acute phase, a warm compress, trigger point release, and stretching will help. In the maintenance phase, back strengthening exercises are taught to maintain core strength.
Medications that can be used are paracetamol with or without a muscle relaxant, nonsteroidal anti-inflammatory drugs (NSAIDS; avoid in patients with stomach ulcers or renal dysfunction), COX-2 inhibitors (avoid in patients with renal dysfunction), opioids (powerful painkillers that should only be given for short defined durations and usually given to postoperative patients), and tricyclic antidepressants (eg, amitriptyline) or antiepileptics (eg, gabapentin, pregabalin) for neuropathic pain.
If analgesics or physiotherapy fail to alleviate the problem, or if there are “red flags” such as neurological deficits present, the patient should be referred to a specialist.
Surgery is only employed when there is failure of conservative therapy. The type of surgery is customized to the specific problem of that patient. In general, spine surgery seeks to achieve two things – decompression of neural elements and restoring stability to the spine if needed. Decompression of neural elements is achieved by laminotomy and/or discectomy. Restoration of spinal stability is achieved by instrumented fusion using a combination of screws and rods.
There are no local guidelines for lower back pain. The 2009 National Institute for Health and Care Excellence (NICE) guidelines (UK) and 2015 National Institutes of Health (NIH) low back pain fact sheet are good sources of information for lower back pain. They cover the causes of lower back pain, diagnosis and management options.
It is important to address low back pain at the primary care level by proper assessment, early intervention and knowing when to refer onwards to specialist clinics or the emergency department. If not done correctly, it will overload the specialist clinics in public hospitals and at worst, cause a delay in diagnosis or result in a missed diagnosis.
NIH fact sheet
http://www.ninds.nih.gov/disorders/backpain/detail_backpain.htm (NIH low back pain)
American Chronic Pain Association factsheet