What are the physical findings characteristic of cauda equina and conus medullaris syndrome?

Updated: Jun 14, 2018
  • Author: Segun Toyin Dawodu, JD, MD, MS, MBA, LLM, FAAPMR, FAANEM; Chief Editor: Nicholas Lorenzo, MD, MHA, CPE  more...
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Answer

The salient features and findings of cauda equina syndrome and conus medullaris syndrome are listed in Table 4, below.

Table 4. Cauda Equina Versus Conus Medullaris Syndrome (Open Table in a new window)

Features

Cauda Equina Syndrome

Conus Medullaris

Vertebral level

L2-sacrum

L1-L2

Spinal level

Injury to the lumbosacral nerve roots

Injury of the sacral cord segment (conus and epiconus) and roots

Severity of symptoms and signs

Usually severe

Usually not severe

Symmetry of symptoms and signs

Usually asymmetric

Usually symmetric

Pain

Prominent, asymmetric, and radicular

Usually bilateral and in the perineal area

Motor

Weakness to flaccid paralysis

Normal motor function to mild or moderate weakness

Sensory

Saddle anesthesia, may be asymmetric

Symmetric saddle distribution, sensory loss of pin prick, and temperature sensations (Tactile sensation is spared.)

Reflexes

Areflexic lower extremities; bulbocavernosus reflex is absent in low CE (sacral) lesions

Areflexic lower extremities

(If the epiconus is involved, patellar reflex may be absent, whereas bulbocavernosus reflex may be spared.)

Sphincter and sexual function

Usually late and of lesser magnitude;

lower sacral roots involvement can cause bladder, bowel, and sexual dysfunction

Early and severe bowel, bladder, and sexual dysfunction that results in a reflexic bowel and bladder with impaired erection in males

EMG

Multiple root level involvement; sphincters may also be involved

Mostly normal lower extremity with external anal sphincter involvement

Outcome

May be favorable compared with conus medullaris syndrome

The outcome may be less favorable than in patients with CES


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