BACK PAINMusculoskeletal and Soft-tissue Emergencies 331● Severe or atypical, non-traumatic back pain
● Mild to moderate, non-traumatic back pain.
Direct back trauma
Back pain that follows direct trauma is managed according to the principles in
the appropriate section on multiple injuries (see p. 245).
Indirect mechanical back trauma
DIAGNOSIS
1 Bending, lifting, straining, coughing or sneezing may precipitate acute,
severe low back pain.
2 There is intense muscle spasm, or even complete immobility. The normal
lumbar lordosis is lost, with development of a scoliosis.
3 Assess for any reduction in straight-leg raise (SLR), suggesting sciatic nerve-
root irritation.
(i) Inability to leg raise more than 30° due to pain going down the
leg is abnormal.
(ii) Remember that being able to sit up in bed with the legs out
straight is equivalent to a SLR of 90° on both sides.
4 Examine for neurological signs of nerve-root irritation or compression from
an acute prolapsed intervertebral disc.
(i) Look for motor loss occurring in the following myotomes:
(a) L1, L2 – hip flexion (iliopsoas)
(b) S1 – hip extension (gluteus maximus)
(c) L5 – knee flexion (hamstrings)
(d) L3, L4 – knee extension (quadriceps)
(e) L5 – ankle dorsiflexion (extensor hallucis longus)
(f) S1 – ankle plantar flexion (calf muscles).
(ii) Check for reduced or absent reflexes:
(a) L3, L4 – knee jerk
(b) L5, S1 – ankle jerk.
(iii) Assess for sensory loss in the following dermatomes:
(a) L3 – medial lower thigh and knee
(b) L4 – medial side of calf
(c) L5 – lateral side of calf
(d) S1 – lateral border of the foot and sole.
5 Central disc prolapse
Always assess for any signs of a central disc prolapse causing cauda equina
compression. Look for the following diagnostic features:
(i) History of difficulty emptying the bladder or bowels.
(ii) Saddle-area anaesthesia over dermatomes S2, S3, S4 and S5.
(iii) Weakness in both legs.
(iv) Lax anal sphincter tone on p.r. examination.