By Dr Ramesh Vadapalli, MS (Trauma & Spine Surgeon)
Low back pain (lumbago) is a common musculoskeletal disorder affecting 80% of people at some point in their lives. There is no age bar for low back pain but it is very unusual in children and adolescents. Most cases of low back pain are due to a sprain or strain in the muscles of the back mainly due to faulty postures in daily activities. Degeneration of bones, spondylolisthesis (vertebra slipping on each other) and osteoporosis are common causes in old age. Serious causes like fractures, tumours and infection account for less than 1 per cent.
One of the most common causes of lumbago apart from sprains and strains is disc prolapse (4 per cent). Commonly used terms are disc bulge, herniated disc, disc prolapse, pinched nerve, sciatica and ‘slipped disc.’ In fact the disc does not slip, instead it bursts.
The spine consists of 33 bones (vertebrae) piled up in an ‘S’ shaped manner forming three curves. These curves maintain the centre of gravity of the body. Any alteration in one of these curves places an undue strain on the back.
In between these vertebrae lies a cushion (intervertebral disc); the disc has an outer tight annulus fibrosus and an inner gel (nucleus pulposus). The disc acts as a shock absorber by absorbing and distributing forces on the spine, giving flexibility and protecting the spinal cord and nerves.
The lower back (lumbar region) has five vertebrae (L1-L5) and 5 lumbar discs forming the support structure of a person’s body weight. The lumbar area has most movement and flexibility and thus lumbar discs are more prone to stresses. Lumbar disc prolapse is 15 times more common than cervical disc (neck) herniation. Thoracic discs are rare (1%).
Most disc herniations occur when someone is in their thirties or forties. After age 50, a degeneration of the bones causes a pinching of the nerves leading to low back pain or sciatica. Lumbar disc prolapse occurs most often between the fourth and fifth lumbar vertebral bodies or between the fifth and the sacrum. These are due to both genetic factors and wear and tear due to jobs that require constant sitting, or lifting weights. The disc bursts because of a tear in the outer annulus fibrosus and the jelly like inner nucleus pulposus moves backwards and presses on the spinal cord and nerves running close to the disc, producing pain.
The symptoms of a lumbar herniated disc are episodes of continuous low back pain associated with a sharp, stabbing pain radiating down into the buttock, back of thigh, calf, foot and toes (sciatica or radicular pain). Some experience numbness, tingling, muscle weakness and paralysis. Typically, symptoms are experienced only on one side. If the prolapse is very large then it affects both legs.
Pain caused by disc herniation is worse in sitting and bending positions. The pressure on the disc increases during sitting and bending. In some, pain is increased on sneezing and coughing. If the prolapse is severe it causes cauda equina syndrome (urinary incontinence, weakness in legs and decreased sensation in genital area).
Diagnosis and treatment
An X-ray gives us a clue about the presence of a herniated disc.
The gold standard modality for visualizing the herniated disc is a magnetic resonance imaging (MRI) scan.
X-ray (1) MRI (2) MRI (3)
Arrow shows Narrowed space between L5 and S1 vertebrae, indicating probable prolapsed disc.
(2) Arrow showing disc prolapsed at L5-S1 level.
MRI showing L4_L5 disc prolapsed pressing on spinal cord.
Non operative treatment
70 per cent of patients with herniated discs with low back pain respond well to conservative therapy in about six weeks and do not require surgery. This is first attempted with bed rest, pain relieving medications, physical therapy, tractions, a lumbar belt and patient education. The strengthening of the abdominal and back muscles can relieve symptoms in patients with radicular pain. A steroid injection is given into the spine (‘epidural injection’) but this gives short-term pain relief in selected patients only; spinal manipulation is absolutely contraindicated.
Operative treatment
Surgery is considered as a last resort after all conservative treatments (non-surgical therapy) have been tried, and if radicular pain persists after 6 weeks with frequent episodes of muscle
weakness in legs. A disc causing cauda equine syndrome is a medical emergency requiring immediate attention and possibly surgical intervention.
Various types of surgical treatment are available, and commonly performed surgery is laminectomy and discectomy. The goal of this surgery includes the removal of a piece of bone and prolapsed disc, and removing pressure on the spinal cord and nerve, allowing it to recover.
Important tips to
prevent back attack
– Good posture decreases the amount of stress on the disc. A good standing posture consists of having one’s ears, shoulders, hips, and knees all in one line.
– Avoid staying too long in any position, change positions often. Prolonged sitting puts strain on the lower back, so walk around frequently.
– Wear comfortable shoes, avoid high heels.
– Mattresses that are too hard or too soft will cause back pain.
– Reduce abdominal fat.
– Stretching and aerobic exercises prevent osteoporosis and reduce strain on back muscles.
– When lifting a heavy object keep the object close to your body and bend your knees and hips.
– When you sit, do not slouch and use a lumbar pillow in your chair.
– Use a foot rest when you sit.
– Sit close to the pedals while driving.
– Put a pillow under your knees when you sleep on your back.
– Avoid smoking; this limits blood flow to the discs and muscles and slows healing.
Back pain is a common complaint in 50% of pregnant women, mainly due to additional weight as the uterus grows and changes the centre of gravity causing back strain. Hormonal changes during pregnancy also cause back pain.
In certain cases, urinary infections cause back pain. Simple walking is the best exercise. Pregnant women also should follow the above tips.
“An ounce of prevention is worth a pound of cure” this holds good when it comes to low back pain.
By using proper lifting techniques, maintaining good posture and body weight, and keeping the back muscles strong, episodes of ‘back attack’ could be avoided.
