Conus medullaris syndrome is caused by an injury or insult to the conus medullaris and lumbar nerve roots. It is a clinical subset of spinal cord injury syndromes. Injuries at the level of T12 to L2 vertebrae are most likely to result in conus medullaris syndrome.
The conus medullaris lies in close proximity to nerve roots and injury to this region results in combined upper motor neurone and lower motor neurone features
Conus medullaris injury can result most commonly from:
- lumbar canal stenosis due to herniation of intervertebral disc(s)
Patients present with a combination of upper and lower motor neurone palsies and similar features as cauda equina syndrome which include:
- saddle anaesthesia
- loss of bladder reflex: urinary retention
- loss of bowel reflex: incontinence
- lower limb motor weakness, paraesthesia and numbness
- chronic lower backache
Treatment and prognosis
The prognosis depends on upon patient presentation. Early diagnosis and treatment may facilitate improvement in symptoms. Approximately 10% of patients may regain functional recovery.
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- 2. McKinley W, Santos K, Meade M et-al. Incidence and outcomes of spinal cord injury clinical syndromes. J Spinal Cord Med. 2007;30 (3): 215-24. Free text at pubmed - Pubmed citation