Lumbar radicular pain Flashcards
Key
Lumbar radicular pain is caused by irritation of nerve roots.
Between 13% and 40% of people will experience an episode during their lifetime.
The commonest causes are disc herniation and spinal stenosis.
The majority of cases will resolve with conservative management, such as simple analgesia, cognitive behavioural therapy, exercise and physiotherapy.
Interventional treatments include transforaminal epidural steroid injections, coblation nucleoplasty, pulsed radiofrequency treatment and surgery.
Definitions
Lumbar radicular pain
Lumbar radicular pain is a neuropathic pain caused by pathology of the sensory lumbar nerve roots, resulting in radiating pain in a lumbar dermatomal patter
Radiculopathy
Radiculopathy is a term that encompasses a range of symptoms and signs resulting from pathology of the nerve roots.
This includes sensory disturbance, paraesthesia and motor deficit.
Sciatica
Sciatica is a term that is often used synonymously with lumbar radiculopathy. It also refers to neuropathic pain radiating in a lumbar dermatomal pattern with or without motor deficit. The terms radiculopathy, sciatica and radicular pain are often used interchangeably in the literature.2
Anatomy
five lumbar vertebrae,
which are connected by intervertebral discs and articulate posteriorly through paired facet joints
Form cartilaginous joints between the vertebrae
and consist of an outer fibrous ring,
the annulus fibrosus,
which surrounds an inner gel-like centre,
the nucleus pulposus
Roots
The L1–L5 nerve roots originate from the conus medullaris
between the level of T12 and L1 vertebrae and
descend within the spinal canal to exit at the intervertebral foramen
of their respective level.
Once emerged from the intervertebral foramen,
dorsal roots (which carry somatic sensory signals)
+
ventral roots (which carry somatic motor fibres) unite
to form a mixed spinal nerve,
which further divides into the dorsal and ventral rami.
The dorsal rami provide innervation to the paraspinal muscles and the overlying skin.
The ventral rami form part of the lumbosacral plexus and provide sensory and motor supply to the trunk and legs.
Pathophysiology
caused by changes to the normal anatomical structures that surround a nerve root.
Any changes or shifts to these tissues may cause a narrowing
This narrowing may result in mechanical and biochemical insult to the nerve root
vulnerable to damage
lack a perineurium
=
comparatively reduced tensile strength
a decreased diffusion barrier.
diminished epineurium and so have reduced defence against compression
Lumbar disc herniation
Lumbar disc herniation
Lumbar disc herniation, where a damaged annulus fibrosus - a llows the inner nucleus pulposus to herniate through
Form of disc protrusion, where the nucleus material is displaced, causing an outpouching but with the annulus still intact.
May progress to disc sequestration, which is where a free fragment of disc material separates from the disc entirely and can migrate, causing symptoms distant from the original vertebral level
Disc herniation can occur in a central, paramedian, posterolateral or lateral direction. Central herniation into the spinal canal can result in bilateral symptoms, including cauda equina syndrome (CES). Herniation laterally may impact on a nerve root and can result in radicular symptom
Lumbar spinal stenosis
Spinal stenosis is the second most common cause of lumbar radicular pain. Narrowing of the central canal, lateral recess or exit foramina results in damage to nerve tissue, causing radicular symptoms.
Pain is typically exacerbated by standing and walking and can be relieved by leaning forwards
Clinical presentation
Lumbar radicular pain typically affects those in midlife,
with men often afflicted in their 40s and women slightly later in their 50s and 60s.
Overall, there is a male preponderance with the other common risk factors being obesity, smoking, depression and frequent heavy manual labour involving flexion-based lifting.
In those younger than 50 yrs, the aetiology of the nerve injury is most commonly caused by lumbar disc herniation, whereas in the over 50s, it is more likely to be secondary to lumbar spinal stenosis.
Depending on which nerve fibres are affected, sensory and motor symptoms can be present. However, sensory symptoms in the form of lumbar radicular pain are the predominant features, with patients commonly describing a ‘sharp, shooting, lancinating, stabbing or shock-like’ pain travelling from the lower back to the buttock, groin or leg, on one or both sides
Paraesthesia may be present with the typical description of abnormal ‘tingling, burning or prickling’ sensations. Sensory deficits are possible and are related to the affected dermatome. Less commonly, motor fibres in the ventral nerve root may be affected, resulting in the patient reporting weakness, fatigue or cramping in a myotomal distribution
Clinical findings with pathology at different lumbar nerve roots
L1 and L2 Inguinal area Hip flexion
Cremasteric
L3 and L4 Anterior thigh and knee Knee extension Hip flexion Hip adduction
Patellar
L5 Posterolateral thigh and leg Dorsiflexion of foot and toes Knee flexion Hip extension
S1 Posterior thigh and leg Lateral foot Plantar flexion foot Knee flexion Hip extension
Achilles
History and examination
structured approach to history, examination and investigation should be used whilst considering all possible causes, including disease processes external to the spinal canal
diagnosis of lumbar radicular pain as a result of disc compression/stenosis can be made clinically based on compatible symptoms and physical examination
it is essential to rule out sinister causes of radicular symptoms. Urgent imaging and referral are required if ‘red flag’ symptoms or signs are presen
Conservative management
For most people with lumbar radicular pain caused by disc herniation, their symptoms will resolve without intervention, with the majority seeing improvement within 4–6 weeks with conservative management.
Initially, the following management should be offered:
(i) Encourage the person to stay active, resume normal activities and return to work as soon as possible.
(ii) Emphasise that bed rest is not recommended and that normal movements may produce some pain, but this should not be harmful.
(iii) Simple analgesics, such as NSAIDs or a weak opioid (with or without paracetamol), may be offered. Treatment with paracetamol alone is no longer recommended.
(iv) Gabapentinoids, other anti-epileptics, oral corticosteroids and benzodiazepines have no overall evidence of benefit, but they do have evidence of harm.11
For those with pain refractory to the aforementioned treatments, the following should be considered:
(i) Cognitive behavioural therapy.
(ii) Group exercise programme.
(iii) Manual therapy (spinal manipulation, mobilisation or soft tissue techniques such as massage)
(iv) Combined physical and psychological programme: a combination of treatments led by a single therapist (e.g. a physiotherapist) supported by a second discipline (e.g. a psychologist), using a cognitive behavioural approach as part of a treatment package, including exercise, with or without manual therapy.
(v) Referral to a pain specialist.
