Assessment and Management of Focal Weakness in Back Injuries

Essential Clinical Assessment Components

The American College of Radiology recommends testing motor strength in all major lower extremity muscle groups bilaterally, documenting any asymmetry or weakness below the level of suspected injury 2, 1
The American College of Radiology suggests assessing for specific patterns of weakness that localize to particular nerve root levels, including L2-L3: Hip flexion 3, L3-L4: Knee extension (quadriceps) 4, L5: Ankle dorsiflexion and great toe extension 4, and S1: Ankle plantarflexion and knee flexion (hamstrings) 1
The American College of Radiology advises evaluating sacral sensation and function, including perianal sensation, rectal tone, and voluntary anal sphincter contraction, as these predict neurological recovery and bladder function 1

The American College of Radiology recommends testing for saddle anesthesia (perianal or perineal numbness) which indicates cauda equina syndrome requiring urgent imaging 4
The American College of Radiology suggests assessing for progressive neurologic deficits through serial examinations, as worsening weakness mandates immediate advanced imaging 2, 4
The American College of Radiology advises documenting ankle spasticity in patients with thoracolumbar fractures, as this highly predicts neurogenic bladder dysfunction 1

The American College of Radiology recommends using the ASIA Impairment Scale (AIS) for thoracolumbar injuries with neurological deficits, as entry AIS grade predicts functional outcomes 1
The American College of Radiology suggests grading muscle strength using the 0-5 British Medical Council scale for objective documentation and serial comparison 1
The American College of Radiology advises testing abductor hallucis (AbH) motor function specifically, as this predicts neurological recovery in thoracolumbar fractures 1

The American College of Radiology recommends not skipping sacral examination in any patient with back injury and suspected neurological involvement, as sacral sparing versus involvement fundamentally changes prognosis and management urgency 1, 4
The American College of Radiology advises not performing flexion-extension radiographs acutely in patients with neck pain and muscle spasm, as these are unlikely to yield additional diagnostic information and pose injury risk 3

The American College of Radiology recommends recording specific muscle groups tested, strength grades bilaterally, and any asymmetry to enable comparison on serial examinations 1
The American College of Radiology suggests documenting presence or absence of reflexes at multiple levels (patellar, Achilles) as hyperreflexia suggests upper motor neuron involvement 1
The American College of Radiology advises noting any dissociation between imaging findings and clinical deficits, as neurological examination localizes injury more accurately than imaging alone for predicting recovery 1