Dr. Kevin Yip

Dr Kevin Yip
Orthopaedic Surgeon
MBBS(UK), FRCS(EDIN), FAM(SING), FHKCOS(ORTHO)

Featured on Channel NewsAsia

Spinal Stenosis

Basics
Description
  • Compression of neural elements secondary to osteoarthritic changes (bone spurs, hypertrophied ligamentum flavum, disc space narrowing) at intervertebral levels and facet joints
  • Characterized by back and/or lower extremity pain, numbness, weakness, and possible bladder/bowel dysfunction.
General Prevention
No known preventive measures
Epidemiology
  • Symptoms develop during the 5th and 6th decades.
  • No gender predominance
  • Degenerative spondylolisthesis with spinal stenosis is 4 times more common in females .
Incidence
1.7-8%
Risk Factors
Increasing age and spinal arthritis
Genetics
No definitive genetic links
Pathophysiology
  • Disc dehydration leads to loss of height with bulging of the annulus and ligamentum flavum into the spinal canal, thus increasing joint loading of the facets.
  • Increased joint loading leads to reactive sclerosis and osteophytic bone growth, which in turn leads to additional compression of the neural elements.
Etiology
  • Congenital:
    • Chondrodystrophy
    • Idiopathic
  • Acquired:
    • Degenerative
    • Spondylolytic
    • Iatrogenic
    • Posttraumatic
    • Paget disease
Diagnosis
  • Long-standing back pain that progresses to buttock and lower extremity pain
  • Neurogenic claudication (pain, tightness, numbness, and subjective weakness of lower extremities)
  • Symptoms worsen with standing, walking, and back extension.
  • Symptoms improve with sitting or leaning forward.
Signs and Symptoms
History
  • Insidious onset
  • Progresses slowly
  • Symptoms worse when walking uphill and improve with leaning forward (e.g., while pushing a cart in a grocery store)
Physical Exam
  • Few physical findings may be present even in affected patients.
    • Gait alteration (Rule out cervical myelopathy or intracranial pathology.)
    • Loss of lumbar lordosis
    • Decreased ROM of the lumbar spine
    • Straight-leg-raise test may be positive if nerve root entrapment is present.
    • Muscle weakness, most commonly in the L5 distribution.
    • Consider rectal examination to rule out cauda equina syndrome in selected patients.
Tests
Spinal stenosis usually is diagnosed with a combination of history, physical examination, and imaging studies.
Lab
Complete blood cell count, C-reactive protein, and ESR usually are used if infection or cancer is in the differential diagnosis.
Imaging
  • AP and lateral spine radiographs:
    • Show degenerative changes or spondylolisthesis
    • Rule out fractures, infection, or tumor
    • Flexion/extension views help evaluate instability.
  • MRI shows compression of neural elements.
  • CT-myelography:
    • Comparable to MRI in showing neural compression, but an invasive procedure (contrast injection associated with subsequent headache)
    • Often obtained in patients who have had previous spinal instrumentation or cannot tolerate an MRI examination (e.g., those with claustrophobia, pacemaker)
Diagnostic Procedures/Surgery
Selective injections can be used to localize the source of pain in patients with multiple sites of neural compression and unclear findings.
Pathological Findings
  • Decreased disc height
  • Facet hypertrophy
  • Spinal canal and/or foraminal narrowing
  • Disc herniation of bulging
  • Possible intervertebral instability
Differential Diagnosis
  • Vascular claudication (symptoms do not improve with leaning forward)
  • Cervical myelopathy
  • Spinal stenosis in the thoracic spine
Treatment
General Measures
  • Brace or corset may help for a short time, but it is not recommended for long term because it leads to paraspinal muscle weakness.
  • Weight loss
Activity
As tolerated, as long as no other pathology (e.g., fractures, gross instability, etc.) is present

Special Therapy
Physical Therapy
  • General conditioning (Patients can ride an exercise bicycle without many problems because they can lean forward and relieve symptoms.)
  • Aquatic therapy
  • Back extensor muscle strengthening
  • Abdominal muscle strengthening
  • Gait training
Medication
No role for maintenance opiates
First Line
  • Anti-inflammatory medications (in absence of gastrointestinal side effects)
  • Enteric-coated aspirin (fewer gastrointestinal side effects)
  • Acetaminophen
Second Line
  • COX-2 inhibitors (Be aware of a changing side-effect profile.)
  • Lumbar epidural steroids
Surgery
  • Indicated when nonoperative treatment fails, and the patient cannot attain a tolerable quality of life.
    • Preoperative clearance by an internist, cardiologist, and/or anesthesiologist is necessary.
  • Decompression of neural elements is a mainstay of treatment.
    • Generally includes a laminectomy, but foraminotomies and discectomy also should be performed if they are involved in neural compression
  • Fusion is necessary in the presence of instability or if extensive decompression results in instability (with disruption of the pars interarticularis and/or >50% of articular facets)
  • Instrumentation with pedicle screws commonly is used to achieve fusion.
Follow-up
Routine follow-up is at 6 weeks, 3 months, 6 months, 1 year, 2 years, and then every 2 years.
Prognosis
  • Spinal stenosis generally worsens with time.
  • Surgery is successful in improving pain and symptoms in patients for whom nonoperative treatment fails.
Complications
  • Severe spinal stenosis can lead to bowel and/or bladder dysfunction.
  • Surgical complications include infection, neurologic injury, pseudarthrosis, chronic pain, and disability.
Patient Monitoring
Patients are monitored for resolution of symptoms, fusion (if arthrodesis was performed), and development of any complications.
Miscellaneous
Codes
ICD9-CM
  • 723.0 Cervical spinal stenosis
  • 724.00 Spinal stenosis
  • 724.02 Lumbar spinal stenosis
Patient Teaching
Patients should be educated about the natural history of the condition and about awareness of progressive motor weakness and bladder/bowel dysfunction.

FAQ
Q: What is the most common symptom of spinal stenosis?
A: Positional pain (worse with lumbar spine in extension and better with lumbar spine in flexion).
Q: What is the best imaging modality to diagnose spinal stenosis?
A: MRI.

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