- Lumbar back pain is one of the commonest causes of chronic
disability
- Usually due to abnormality of intervertebral discs at L4/5 or L5/S1
level
Pathology
- With age nucleus pulposus of disc dries out
- Annulus fibrosis also develops fissures
- Nuclear material may herniate through annulus
- May perforate vertebral end-plate to produce a Schmorl node
- Flattening of the disc with marginal osteophyte formation is known
as spondylosis
- Osteoarthritis may develop in the facet joints
- Osteophyte formation may narrow lateral recesses of spinal canal
- These can encroach on spinal canal and result in spinal stenosis
- Acute herniation of disc contents can occur
- Usually occurs to one side of the posterior longitudinal ligament
- Posterolateral rupture can compress nerve roots
- Central posterior rupture can compress the cauda equina
Acute disc rupture
- Can occur at any age
- Usually occurs in fit adults between 20-45 years
Clinical features
- Presents with acute low back pain on stooping or lifting
- Pain often radiates to buttock or leg
- May be associated with paraesthesia or numbness in the leg
- Cauda equina compression can cause urinary retention
- Examination may show a 'sciatic' scoliosis
- All back movement is restricted
- May be lumbar tenderness and paravertebral spasm
- Straight leg raising is often restricted
- Neurological examination is essential
- L5 root signs include:
- Weakness of hallux extension
- Loss of knee reflex
- Sensory loss over the lateral aspect of the leg and dorsum of the
foot
- S1 root signs include:
- Weakness of foot plantar flexion
- Loss of ankle reflex
- Sensory loss over the lateral aspect of the foot
- Cauda equina compression causes
- Urinary retention
- Loss or perianal sensation
Imaging
- Lumbar spine x-ray will exclude other bone lesions
- Myelography is a historical investigation
- MRI is now the investigation of choice
Management
- Bed rest is of unproven benefit
- Recovery is not hasten by traction
- NSAID provide symptomatic relief
- The role of epidural steroid injection is unclear
- Chemonucleolysis is less effective than surgical discectomy
- Surgery is required if:
- Cauda equina compression - neurosurgical emergency
- Neurological deterioration with conservative management
- Persistent symptoms and neurological signs
- Surgical options are:
- Partial laminectomy
- Microdiscectomy
- Postoperative rehabilitation and physiotherapy are essential
Facet joint dysfunction
- Usually present with recurrent low back pain
- Pain often related to physical activity
- May be referred to the buttock
- Often relieved by lying down
- Lumbar spine movement is often good
- Neurological signs may be few
- Lumbar spine x-rays show narrowing of the disc space
- Oblique views may show facet joint malalignment
- Treatment includes:
- Physiotherapy
- Analgesia
- Facet joint injections
- Spinal fusion
Spinal stenosis
- Narrowing of the spinal canal due to hypertrophy of the posterior
disc margin
- May be compounded by facet joint osteophyte formation
- Spinal stenosis may also be associated with:
- Achondroplasia
- Spondylolisthesis
- Paget's disease
- Usually presents with either unilateral or bilateral leg pain
- Initiated by standing or walking
- Relieved by sitting or leaning forward - 'spinal claudication'
- Patient prefers to walk uphill rather than downhill
- X-rays often show degenerative spondylolisthesis
- Diagnosis can be confirmed by MRI
- Often treated conservatively
- Surgery involves wide laminectomy and decompression
Spondylolisthesis
- Spondylolisthesis means forward shift of the spine
- Occurs at L4/L5 or L5/S1 level
- Can only occur if facet joint locking mechanism has failed
- Classified as:
- Dysplastic - 20%
- Lytic - 50%
- Degenerative - 25%
- Post-traumatic
- Pathological
- Postoperative
- In lytic spondylolisthesis the pars interarticularis is in two
pieces (spondylolysis)
- Vertebral body and superior facet joints subluxate and dislocate
forward
- Degree of overlap is usually expressed as percentage
- Cauda equina or nerve roots may be compressed
- Presents with back pain and neurological symptoms
- Patients have a characteristic stance
- A 'step' in the lumbar spine may be palpable
- Diagnosis can be confirmed on a plain x-ray
- Most patients improve with conservative management
- Surgery may be required if:
- Disabling symptoms
- Progressive displacement more than 50%
- Significant neurological compromise
- Anterior or posterior fusion may be required
Bibliography
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Koes B W, van Tulder M W, Thomas S. Diagnosis and
treatment of low back pain. BMJ 2006; 332: 1430-1434.
Nelemas P J, de Bie R A, de Vet H C, Sturmans F.
Injection therapy for subacute and chronic low back pain.
Cochrane Database Syst Rev 2000; 2: CD001824.
van Tulder M W, Scholten R J, Koes D C V, Deyo R A.
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