Sciatica -Lumbar radiculopathy

Sciatica – lumbar radiculopathy review on A4Medicine.  This chart starts with the basic of anatomy, pathophysiology, and causes of sciatica. Following sections on assessment and risk stratifications, current evidence based pharmacological management is discussed. Evidence on conservative and surgical management is presented with a link to Backcare – the charity for back and neck pain. The user should also consider viewing another chart on the topic ” Low back pain ” which is available in musculoskeletal medicine.Also known as Sciatic neuralgia Radicular pain Lumbosacral radicular syndrome Radiculopathy Ischias Nerve root pain Nerve root entrapment

Sciatica is a set of symptoms rather than a specific diagnosis and is caused by a herniated lumbar disc in the vast majority of cases.Often applied to any presentation of low back and leg pain Lumbosacral radiculopathy is a more specific term – impingement of lumbosacral nerve roots as they emerge from the spinal canal
 4th and 5th Lumbar nerve roots ( L4-L5 )
First two Sacral (S1 and S2 ).Sciatic nerve- largest nerve in body Disturbance anywhere along the course of the sciatic nerve 
can cause –> Sciatica
○ most common are disc ruptures and osteoarthritis at
L4 – L5
L5 – S1
L3 – L4 – less frequently
 Radiating pain , tingling and numbness – dermatomal distribution
may be accompanying motor weakness in a corresponding myotomal distribution
 Symptoms typically extend 
○ below the knee from buttocks
○ across the back of thigh
○ outer calf
○ often to foot and toes.Acute sciatica
 generally has a 
 good prognosis with pain and disability usually improving within 
2-4 weeks- with or
 without treatment

Back pain accounts 
for 7 % of GP consultations
 and more than 30 % of people still have clinically 
significant symptoms 
after a year after onset of sciatica .Causes- Herniated intervertebral disc ( slipped disc ) with nerve root compression 90 % of cases Lumbar stenoses Spondylolisthesis – a proximal vertebra moves forward relative to a distal vertebra Infection ( rare ) Cancer ( rare ) – often due to metastatic disease Genetic factors ( could have a role in disc degeneration and herniation ).Asymptomatic disc
 herniation on CT/MRI are 
common and there is no
 clear relationship between
 the extent of disc protrusion 
and the degree of clinical 
symptoms

Mainly diagnosed by history and clinical examination Usually unilateral
B/L pain may happen with 
♦ central disc herniation
♦ lumbar stenosis
♦ spondylolisthesis Drawings may be used to evaluate the distribution Increased back and sciatic pain with coughing , sneezing , straining or other forms of Valsalva maneuver may suggest disc rupture
 S1 compression –> reduction or loss of ankle reflex
L3-L4 compression –> variable reduction in knee reflex
L5 compression –> inconsistent changes in reflexes
 Straight leg raise test – Lasègue’s test
Positive test –> reproduction or marked worsening of the patients initial pain and firm resistance to further elevation of leg Sensitivity 90 % but specificity low. Cross straight- leg-raising -test 
( Fajersztajn’s test ) involves raising the unaffected leg

Red flags- Cauda equina syndrome
 Spinal fracture
 Cancer
 Infections
as discitis , vertebral osteomyelits or 
spinal epidural abscess

Differential diagnosis- Osteoarthritis- referred pain from hip Spondyloarthopathies – eg sacroillitis in ankylosing spondylitis Intervertebral facet joint pain Trochanteric bursitis Piriformis syndrome Peroneal palsy or other neuropathies Spina claudication Aseptic necrosis of femoral head Myelopathy or a higher cord lesion Non specific causes as
○ prostatitis
○ PID
○ Pelvic mass
○ Aortic aneurysm
○ Pancreatitis
○ Acute cholecytitis

Unilateral leg pain greater than low back pain Pain radiating to foot or toes Numbness and paraesthesia in the same distribution SLR induces more leg pain Localised neurology – that is limited to one nerve root.Do not routinely offer imaging in a non-specialist setting for people with LBP with or without sciatica ( NICE )
 X ray not routinely recommended – discs cannot be seen on XR

During 1 yr f/u irrespective of a surgical or conservative management- MRI findings seem not helpful in determining which patients might fair better with early surgery compared with a strategy of prolonged conservative management 
( J Neurosurg Spine Jun 2016 )

Referral for further care- Red flag symptoms and signs- admit / refer urgently as appropriate Consider referral to Physiotherapy for
○ manual therapy – spinal manipulation , mobilisation or massage as part of a treatment package including exercise Progressive persistent or severe neurological deficit ( Neurosurgery or T/ O ) Consider referral to specialist LBP & sciatica service for assessment of an epidural corticosteroid / local anaesthetic injection Consider referral for spinal decompression when non surgical treatment has not improved pain or function NICE also recommends referral to rediofrequency denervation if conservative treatment nor worked – main source of pain from structures supplied by medial branch nerve and pain is rated 5 or more on a visual analogie scale

management- NSAIDs- carry out risk assessment + gastroprotection for short term relief Weak opioids ( with or without paracetamol) only if NSAID is contraindicated , not tolerated or has been ineffective Do not offer weak opioids for managing chronic lower back pain Do not offer paracetamol alone Anti-epileptics
Pregabalin – poor evidence ( NEJM 2017 ) does not decrease pain
Gabapentin – has shown greater efficacy in pain reduction compared to placebo

 


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