approach to sciatica
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Approach to sciatica
Shekar RoopanKing Dinuzulu Hospital
Introduction
• Lower back pain - 84% lifetime incidence
• Sciatica
• 13-40% lifetime incidence
• 1-5% annual incidence
• 90% don’t seek help after 3 months
Osseous anatomy
Neuroanatomy
Neuroanatomy
Intervertebral disc• Crucial biomechanical role
• Distributes compressive forces across bodies
• Permits a small degree of movement
• Shock absorption
• Composed of annulus fibrosis and nucleus pulpous
Annulus fibrosis• Concentric laminae of type
1 collagen (15-20)
• Alternative layers are at 30-60 degree angles
• Provides resistance to forces in any direction and hoop stresses
Nucleus pulposus• Hydrophilic proteoglycans with
type 2 collagen
• High water content (90-70%)
• Deforms like fluid when compressive forces applied spreading hydraulically to equalise the forces
• Reduced ability to deform with age as water content decreases
Definitions
• Sciatica - radicular pain in the distribution of the sciatic nerve
• Radicular pain - pain perceived as arising in a limb or the trunk caused by ectopic activation of nociceptive afferent fibres in the spinal nerves or roots
Aetiology• Discogenic - Lumbar disc
herniation
• Non discogenic:• Extraspinal:
• Muscular compression - piriformis syndrome
• Bony - sacroilitis, hip disorders
• Vascular - aneurysms
• Gynaecological - MFU, pelvic endometriosis
• Intraspinal:
• Bony compression - spinal stenosis, spondylolistheisis, osteophytes, facet syndrome
• Infection - caseating disease, abscess, discitis
• Malignancy - schwannomas, metastasis
MA Stafford; Sciatica: review of history, epidemiology and pathogenesis; BJA 2007
Aeitology• Discogenic - Lumbar disc
herniation
• Non discogenic:• Extraspinal:
• Muscular compression - piriformis syndrome
• Bony - sacroilitis, hip disorders
• Vascular - aneurysms
• Gynaecological - MFU, pelvic endometriosis
• Intraspinal:
• Bony compression - spinal stenosis, spondylolistheisis, osteophytes, facet syndrome
• Infection - caseating disease, abscess, discitis
• Malignancy - schwannomas, metastasis
MA Stafford; Sciatica: review of history, epidemiology and pathogenesis; BJA 2007
Pathophysiology
MA Stafford; Sciatica: review of history, epidemiology and pathogenesis; BJA 2007
Failure of disc• Classic teaching - rupture of annulus fibrosis
results in disc herniation
• Rajasakeran et al:
• Avulsion of the end plate together with annulus in majority of patients (65%) - Type 1 (End plate junction failure)
• Disruption of annulus only (35%) - Type 2
Rajasekaran S et al; The anatomy of failure in lumbar disc herniation: an in vivo, multimodal, prospective study of 181 subjects. Spine 2013
Type of herniations
Clinical presentations
Far lateral disc herniations
• Affect nerve roots at more than one level
• Affect nerve roots that have already exited the canal
Cauda equina syndrome
• Usually due to central herniation
• Emergency
• Features:
• Bladder and bowel incontinence
• Perineal numbness
• Bilateral sciatica
• Lower limb weakness
• Crossed straight leg raise
History• Pain
• Site
• Onset
• Character
• Radiation
• Associations
• Time course
• Exacerbating/relieving factors
• Severity
History
• Neurology - bowel and bladder, lower limb weakness, paraesthesia
• ADLS
• Constitutional symptoms
• Psychosocial
Examination• General
• Gait
• Spinal
• Neurological
• PR
• Systemic
Clinical tests• Straight leg raise test
• Lasegue’s test
• Bowstring test
Waddell’s signsPsychological distress amplifying symptoms resulting in anatomically inappropriate signs
• Superficial non anatomic tenderness
• Stimulation sign - exaggerated response to axial compression or rotation
• Distraction sign - SLR varies in sitting and lying down
• Regional sensory or motor disturbance - non anatomical distribution of symptoms e.g. glove and stocking
• Overreaction - theatrical reaction to gentle examination
Radiology
• MRI
• X-rays - disc space, osteophytes
• CT scan
• Myelography - side effects
Modic changes• Signal intensity changes in vertebral body
marrow adjacent to the endplates of degenerative discs
Oedema Fatty Sclerosis
Knutsons phenomenon
• Collection of gas within the disk space, the vertebral body, the apophyseal joint or the spinal canal
• observed in degenerative disk disease
Natural history• 90% improvement by 12 weeks
• Reduction in herniation size due to enzymatic digestion
• Large herniation and sequestered fragments more likely to reabsorb
• Nucleus pulposus more readily absorbed than annulus or end plate
Management• Usually non operative
• Reassurance
• Short period of rest (no more than 2 days)
• Anti-inflammatory medication
• Analgesics
• Physiotherapy
• Exercise
• Weight loss
Non steroidal anti inflammatories
• Most frequently prescribed medications for LBP
• 51 trials (6057 patients)
• Outcomes:
NSAIDs better than placebo
conflicting evidence that NSAID’s better than
paracetomol
• Conclusion:
NSAID’s effective for short term treatment of acute LBP
insufficient evidence on long term useVan Tulder, Scholten, Koes. The Cochrane Library, Issue 2, 2003
NASS Guidelines• TNF Alpha inhibitors - no benefit
• IV glucocorticosteroids - insufficient evidence
• 5HT receptor inhibitors - insufficient evidence
• Amitriptilline - insufficient evidence
• Physical therapy alone - insufficient evidence but recommended for limited period for mild to moderate symptoms
• Spinal manipulation - option for symptomatic relief
• Traction - insufficient evidence
NASS Evidence-Based Clinical Guidelines for Multidisciplinary Spine Care
Injections• Transforaminal epidural - steroid injection is
recommended to provide short-term (2-4 weeks) pain relief
• Is there an optimal frequency or quantity of injections for the treatment of lumbar disc herniations with radiculopathy? - No evidence to answer question
• Approach (?caudal, transforaminal, interlaminar) - No evidence
NASS Evidence-Based Clinical Guidelines for Multidisciplinary Spine Care
Ancillary treatments
• bracing, electrical stimulation, acupuncture and transcutaneous electrical stimulation (TENS) - insufficient evidence
NASS Evidence-Based Clinical Guidelines for Multidisciplinary Spine Care
Operative• Immediate surgery:
• Cauda equina syndrome
• Marked motor loss <48hrs
• Elective surgery - failure of medical treatment
(persistent pain after combined treatment with
NSAIDs, morphine and 3 epidural steroid
injections)
Sciatica from disk herniation: Medical treatment or surgery?;E. Legrand et al. ;Joint Bone Spine (2007)
Operative
• Conventional discectomy
• Micro-discectomy
Similar results with success rate >80%
• Percutaneous discectomy - endoscopic/automated - recommended in carefully selected patients
Sciatica from disk herniation: Medical treatment or surgery?;E. Legrand et al. ;Joint Bone Spine (2007)
Conclusion
• 80% have good prognosis
• Other causes to consider
• Good history and clinical examination
• Mostly non operative management with indications for surgery
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