Cauda equina syndrome

Cauda equina syndrome is a serious neurologic condition in which there is acute loss of function of the neurologic elements (nerve roots) of the spinal canal below the termination (conus) of the spinal cord.

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Causes

After the conus the canal contains a mass of nerves (the cauda equina) which travels caudally (toward the feet).

Any lesion which compresses or disturbs the function of the cauda equina may disable the nerves although the most common is a central disc prolapse.

Other causes include protrusion of the vertebra into the canal if weakened by infection or tumor and an epidural abscess or hematoma.

Signs

Signs include weakness of the muscles innervated by the compressed roots (often paraplegia), sphincter weaknesses causing urinary retention and post-void residual incontinence as assessed by catheterizing after the patient has voided. Also, there may be decreased rectal tone; sexual dysfunction; saddle anesthesia; bilateral leg pain and weakness; and bilateral absence of ankle reflexes. Pain may, however, be wholly absent; the patient may complain only of lack of bladder control and of saddle-anaesthesia, and may walk into the consulting-room.

Diagnosis is usually confirmed by an MRI scan or CT scan, depending on availability. If cauda equina syndrome exists, early surgery is an option depending on the etiology discovered and the patient's candidacy for major spine surgery.

Treatment/management

The management of true cauda equina syndrome is usually urgent surgical decompression.

Cauda equina syndrome is regarded as a medical emergency. Surgical decompression may be undertaken within 48 hours of symptoms developing if a compressive lesion, e.g. ruptured disc, is demonstrated. This treatment may significantly improve the chance that long-term neurological damage will be avoided. There are, however, no evidence-based medical standards that address the question of ultra-early versus delayed (48 hours) surgical decompression in cauda equina syndrome due to ruptured lumbar disc.

Prognosis

The prognosis for complete recovery is dependent upon many factors. The most important of these factors is the severity and duration of compression upon the damaged nerve(s). As a general rule the longer the interval of time before intervention to remove the compression causing nerve damage the greater the damage caused to the nerve(s).

Damage can be so severe and/or prolonged that nerve regrowth is impossible. In such cases the nerve damage will be permanent. In cases where the nerve(s) has been damaged but is still capable of regrowth, recovery time is widely variable. Quick surgical intervention can lead to complete recovery almost immediately afterward. Delayed or severe nerve damage can mean up to several years recovery time because nerve growth is exceptionally slow.