18 Treatment of Acute Cauda Equina Syndrome

10.1055/b-0035-121764

18 Treatment of Acute Cauda Equina Syndrome

Harel Deutsch

Introduction

Acute cauda equina syndrome is the sudden compression of the nerves in the lumbar cistern resulting in pain and neurologic impairment. The spinal cord ends at approximately the L1 to L2 levels and, therefore, cauda equina compression involves the nerve roots rather the spinal cord. Clinically it may not be possible to differentiate between a conus medullaris injury versus a cauda equina syndrome. Neurologic manifestations include bilateral leg weakness, loss of sensation, and bladder and bowel problems. True cauda equina syndrome is rare because the nerve roots are more resistant to compression than the spinal cord. Acute cauda equina syndrome therefore requires severe compression and a rapid onset of compression. Causes include an acute lumbar disk herniation or a lumbar fracture/dislocation. Chronic compression is an extremely rare cause of cauda equina symptoms. Treatment involves generally a wide lumbar laminectomy and removal of the compression. In cases where there is a fracture or dislocation, spinal reduction and instrumentation may be necessary. Other causes of cauda equina syndrome include hematomas, tumors, and infections such as epidural abscesses.

Indications

Patients with acute cauda equina syndrome have leg weakness, decreased lower extremity sensation, and bladder retention. Imaging studies show severe lumbar acute compression. Patients also generally have severe lower back and bilateral leg pain.
Some lumbar stenosis is a common finding on magnetic resonance imaging (MRI) scans. Cauda equina syndrome is not possible unless the stenosis is very severe. Additionally, most patients with very severe lumbar stenosis do not have cauda equina syndrome. For a cauda equina syndrome to occur there usually is an acute worsening of the baseline stenosis. Sometimes a small acute disk may be superimposed on chronic severe stenosis.
Patients with acute cauda equina syndrome have urinary retention. Bladder catheterization after the patient tries to void allows documentation of the post void residual. A post void residual over 100 mL suggests a neurogenic bladder.
Bowel function is not usually apparently disturbed in acute cauda equina syndrome. Patients may have severe constipation and impacted stool. Diarrhea or “loss of bowel” issues are not common findings in acute cauda equina syndrome.
For patients with a traumatic lumbar fracture as the cause of an acute cauda equina syndrome, surgery may be required to address neurologic issues as well as spinal column stability.
This chapter depicts decompression for an acutely herniated lumbar disk causing significant spinal canal compromise.

Preprocedure Considerations

Radiographic Imaging

MRI is the preferred imaging study to evaluate for severe lumbar compression. T2-weighted MRI is excellent in showing the absence high intensity cerebrospinal fluid signal at the level of the compression ( Fig. 18.1 ).
If MRI in unavailable or patient factors preclude getting an MRI, then a computed tomography (CT) myelogram may demonstrate severe stenosis or a complete block to contrast flow at the level of compression.
For patients with traumatic lumbar fractures, X-rays and CT scans are essential to evaluate alignment and fractures.

Medication

Antibiotics are administered prior to incision.
Updated guidelines released in 2013 recommend against the use of steroids in spinal cord injury. The guidelines conclude, “In summary, there is no consistent or compelling medical evidence of any class to justify the administration of MP [methylprednisolone ¹ ^, ² ] for acute SCI [spinal cord injury]. Both consistent and compelling Class I, II, and III medical evidence exists suggesting that high-dose MP administration is associated with a variety of complications including infection, respiratory compromise, GI hemorrhage, and death. MP should not be routinely used in the treatment of patients with acute SCI.” ³

Foley Catheter Placement

Patients may have significant urinary retention leading to hypotension because of bladder distension.

Operative Field Preparation

Alcohol prep is performed before povidone iodine or chlorhexidine application.
The incisions are marked and infiltrated with 1% lidocaine with epinephrine 1:100,000.