Conus Medullaris Syndrome Diagnosis and Management

Anatomy and Pathophysiology

The conus medullaris is typically located at the end of the spinal cord, ending at the L1-L2 disc space by 2 months after birth, and a conus medullaris that ends below the middle third of the L2 vertebra is considered tethered, according to the American Academy of Pediatrics 1, 2

Symptoms of Conus Medullaris Syndrome (CMS) are age-dependent and may include pain, sensorimotor disturbances of the lower limbs, and difficulties with bladder and/or bowel control, as reported by the American Academy of Pediatrics 1, 3
Back and/or leg pain is common and may be dull and aching, sharp, lancinating, electrical, or dysesthetic in character, with pain possibly being aggravated by flexion and extension of the spine or by walking or running, according to the American Academy of Pediatrics 3, 4

MRI is the preferred imaging method for diagnosing CMS, providing better visualization of soft tissue, bone marrow, and spinal canal, as recommended by the American College of Radiology 5

Long-standing untreated tethering can result in progressive musculoskeletal deformities and/or scoliosis, with muscle atrophy becoming apparent, and orthopedic deformities of the feet and spine may develop, according to the American Academy of Pediatrics 3, 4
The skin of the leg and foot may become thin, shiny, and hairless due to autonomic changes with long-standing tethering, as reported by the American Academy of Pediatrics 4

Traumatic spinal cord injuries have an annual incidence ranging from 10 to 85 cases per million persons worldwide, with epidemiological trends evolving to include an increasing proportion of cervical incomplete SCIs in older persons from low-energy or fall-related mechanisms, and the mean age of patients suffering acute spinal cord injury increased from 40.5 years to 50.5 years between 1993 and 2012 in the United States 6

Congenital malformations such as tethered cord syndrome are a non-traumatic cause of CMS, according to the American Academy of Pediatrics 7
Spinal lipomas and other fatty infiltrations of the filum terminale, as well as meningoceles and atretic meningoceles, are rare non-traumatic causes of CMS 8

Bladder paralysis is common in acute presentations of Conus Medullaris Syndrome, according to the Journal of Infection 9

Bladder dysfunction tends to be more prominent and occurs earlier in conus medullaris syndrome (CMS) compared to cauda equina syndrome (CES), and may present as urinary retention, urgency, or incontinence, according to the British journal of neurosurgery 10
Bowel dysfunction is associated with early onset of fecal incontinence in CMS, as reported by the British journal of neurosurgery 10
Neurological examination should focus on assessment of perineal sensation, evaluation of anal tone, and testing of lower limb reflexes, which may be hyperreflexic below the level of lesion, as recommended by the British journal of neurosurgery 10

Hydrocephalus can be a rare complication when associated with certain pathologies affecting the conus medullaris 11

The American Academy of Pediatrics notes that myelomeningocele, the most common dysraphic malformation, is associated with conus medullaris syndrome 12
Spinal lipomas and fatty infiltrations of the filum terminale can cause tethering of the conus medullaris, according to the Pediatrics journal 12

Ischemic and hemorrhagic infarcts can affect the conus medullaris region, as reported by the Journal of the American College of Radiology 13
Demyelinating diseases such as multiple sclerosis can affect the conus medullaris, with a moderate level of evidence, according to the Journal of the American College of Radiology 14
Metastatic tumors to the conus medullaris region are also a consideration, as noted by the Journal of the American College of Radiology 14