see also:

• back pain in the ED
• sciatica
• cauda equina syndrome (CES)
• lumbar disc prolapse

• lumbar disc prolapse at the higher lumbar vertebral discs (L1-L3 level) account for a small minority of all lumbar disc prolapses, and as they generally affect the L2-3 nerve roots the most, and these supply the femoral nerve and not the sciatic nerve, the clinical features, and management are quite different from the usual sciatica features, although they can often overlap as patients may have both high and low level prolapses, and the high level prolapses can sometimes impinge on the lower nerve roots as well.
• a key feature is that the straight leg raising test (SLR) which we use to help us diagnose the usual lumbar disc prolapses is likely to be negative as the femoral nerve runs anterior to the pelvis, and thus pain is more likely to be elicited with extension of the hip rather than flexion, indeed, these patients tend to be more comfortable sitting or with hip and knee flexed
• another key feature is that surgery is not as successful

• these tend to affect more than one nerve root perhaps due to the narrower spinal anatomy
• eg. L1-2 lateral prolapse may affect the exiting L1 or L2 nerves
• L1 root causes pain in groin +/- numbness to inguinal/suprapubic region via the iliohypogastric nerve and ilioinguinal nerve (DDx involves impingment or surgical damage of these nerves more distally such as where they traverse the abominal wall muscles)
• L2 root causes pain in ant-medial thigh
• L3 root causes pain in ant-lateral thigh
• may impact the conus medullaris
• as L2 and L3 are mainly distributed to the femoral nerve, unlike sciatic nerve root compression, SLR will generally be little effected but hip extension, which stretches the femoral nerve, is likely to exacerbate the pain
  • patients may have reduced knee jerk, and may develop wasting of quads and secondary knee instability
• see dermatomes
  • L2 ⇒ low back - just above buttock, ant/lat thigh
  • L3 ⇒ ant. thigh
  • L4 ⇒ ant/lat. proximal lower leg, medial foot including 1st two toes dorsally
• myotomes:
  • L2 ⇒ hip flexion
  • L3 ⇒ quads, patellar reflex
  • L4 ⇒ patellar reflex (with L3)

• initially there is mild midline pain and tenderness over the lumbar vertebral disc but the main clinical feature is neuropathic pain radiating along the dermatomes of the nerve roots involved which may be:
  • lateral pelvic/hip pain +/- anterolateral thigh pain, and/or,
  • groin pain +/- anteromedial thigh pain
• pain may be improved by:
  • hip flexion and external rotation of the hip
  • reduction of lumbar lordosis by activating core muscles and “sucking stomach in”
  • walking (although any sudden jerks need to be avoided - consider a walking aid in the early phases such as a walking stick)
• pain may be exacerbated by:
  • hip extension (avoid taking long steps)
  • prolonged crossing knees (with ipsilateral knee on top) whilst sitting
  • internal rotation of hip such as standing and twisting body outwards
  • increased lordosis (eg. lying on couch in lateral position with a lumbar “support” placed which increases lordosis may actually reproduce the neuropathic pain!
  • attempting to wipe bottom on toilet with ipsilateral hand
  • rolling over in bed
    • try to ensure there is a firm mattress to avoid excessive lordosis
    • roll over in bed by flexing both hips and knees and keeping knees together to provide additional support
    • get out of bed by flexing both hips and knees and rock forwards
  • cough, sneezing or vomiting
    • protect your spine by activating core muscles before sneezing, etc
  • sudden unpredictable movements such as:
    • loss of footing due to uneven ground or not seeing a step down
    • being knocked by someone whilst standing
      • hence a walking stick is a good idea to help address both issues
• severe or prolonged impingement may result in neurologic features such as:
  • loss of knee jerk
  • wasting of quads and iliopsoas muscle
  • sensory changes on the affected nerve root dermatome(s)
  • rarely, cauda equina syndrome (CES) may occur which is a potential indication for emergency surgery

• analgesia sufficient to aid mobility and self care whilst avoiding excessive analgesia or sedation
  • it is important the patient can still feel the pain so they avoid situations which cause further pain and potential nerve damage
  • excessive sedation may increase risk of falls, etc, there is little evidence for use of diazepam to “reduce muscle spasm”, this should be reserved for bed bound patients with severe spasm rather than neuropathic pain
  • excessive analgesics may cause vomiting and this may cause further nerve impingement and pain, and prevent ability to take analgesics
  • in the first 2-3 weeks a combination of paracetamol and non-steroidal anti-inflammatory drugs (NSAIDs) is usually the ideal regime, although some people may require intermittent stronger analgesia such as oxycodone in the first few days - opiates should be avoided as a longer term Rx as there is little evidence they provide real benefits, and they may prolong recovery
  • most of the extreme pains are extremely short lived (seconds to minutes), and often result in the patient collapsing to the floor, particularly if they occur whilst standing on the affected leg such as whilst trying to get into bed (remember external rotation of the body on the affected leg may cause exacerbation of the impingement!), hence opiates are not usually appropriate to manage this, and instead, the patient should avoid situations or movements which cause these episodes as they are likely to prolong the neuropathy
• encourage early mobilisation once tolerated
  • careful walking perhaps with a walking stick initially generally shortens the recovery period dramatically
  • avoid prolonged sitting, and sit with core activated (not slouching) and avoid crossing knees
• NO heavy lifting or pulling weeds in the garden
  • 5kg weight should be the maximum for the first few months
• assess the bed mattress
  • ensure it is firm and not sagging under the buttocks as this will increase lordosis whilst lying prone, as well as hip extension if lying supine, while making rolling over more arduous and prone to exacerbating impingement
• create realistic expectations
  • this WILL impact the way they live and work and they WILL need to modify this or suffer further nerve damage
  • most of the recovery is almost totally dependent upon the patient's efforts to get mobilising, maintain strength and flexibility while avoiding further exacerbations of the prolapse