Cauda Equina and Conus Medullaris

by Kevin Pei, MD

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    00:01 Now, let's visit another important topic called cauda equina.

    00:06 As the name implies, looks like the horse's tail.

    00:09 Remember, normal spinal cord tapers just at the lumbar region.

    00:13 Compression of the lumbar sacral nerve's roots below the level of the conus medullaris causes cauda equina.

    00:21 Do you know what symptoms are included in the cauda equina? I’ll give you a second to think about this.

    00:29 Cauda equina classically is associated with saddle numbness.

    00:33 That’s highlighted here by the green on our manikin.

    00:38 You can see variable areflexic paraplegic or atrophy in the extremities.

    00:45 Sometimes patients have urinary retention.

    00:48 And some patients have severe neuropathic pain.

    00:54 But what's the difference between conus medullaris versus cauda equina? Here’s an important table for its differentiation.

    01:02 Let's go over each section.

    01:04 In conus medullaris, the level of injury is actually at the termination of the spinal cord.

    01:10 This is actually before the tail fiber split.

    01:14 There is usually impotence.

    01:17 Motor exam involves symmetric, hyperreflexia, less marked weakness.

    01:23 Remember, hyperreflexia is a sign of upper motor neuron disease.

    01:27 Sensory loss is usually around the perianal region and it can have rapid symptoms.

    01:34 Generally, patients also complain of bowel and bladder incontinence.

    01:38 Let's compare this to cauda equina.

    01:41 Cauda equina involves again the tracts leading to the peripheral nerve systems.

    01:46 There is variable presentation of impotence.

    01:50 The motor exam, however, is asymmetric depending on the side of the injury or the side that's involved.

    01:56 Unlike, the hyperreflexia in conus medullaris, we see areflexia and profound weakness.

    02:04 And as a reminder, the sensory exam shows the saddle distribution on the previous slide.

    02:09 Generally speaking, the acuity is slower onset.

    02:12 It's important for you to be able to differentiate where the level of the injury is between conus medullaris and cauda equina.

    02:20 Now, it's time to visit some important clinical pearls and high-yield information.

    02:24 Under spinal cord syndromes, it's very important to understand the normal sensory and motor tracts to help you determine where the actual neurological deficits are.

    02:33 Go back to those previous slides and review where all the normal tracts run and their associated sensory or motor deficits.

    02:41 Then you can figure out the syndromes when presented on a clinical scenario.

    02:48 And remember, cauda equina syndrome is potentially a neurosurgical emergency.

    02:52 Don’t sit on these patients for too long.

    02:56 Thank you very much for joining me on this discussion of neurological spinal cord syndromes.

    About the Lecture

    The lecture Cauda Equina and Conus Medullaris by Kevin Pei, MD is from the course Special Surgery.

    Included Quiz Questions

    1. Saddle numbness
    2. Urinary retention
    3. Neuropathic pain
    4. Profound weakness
    5. Hyperreflexia
    1. Slow onset of symptoms
    2. Sensory loss in the perianal area
    3. Bladder incontinence
    4. Impotence
    5. Weakness

    Author of lecture Cauda Equina and Conus Medullaris

     Kevin Pei, MD

    Kevin Pei, MD

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