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Musculoskeletal System Nervous system ORGAN SYSTEMS

Cauda equina syndrome (CES)

Compression of cauda equina group of nerves, resulting in symptoms that include bowel and bladder dysfunction, saddle anesthesia, and varying degrees of loss of lower extremity sensory and motor function.

Introduction

Compression of cauda equina group of nerves, resulting in symptoms that include bowel and bladder dysfunction, saddle anesthesia, and varying degrees of loss of lower extremity sensory and motor function.

  • Orthopedic emergency

Aetiology

Compressive lesions:

It occurs most frequently following a large lower lumbar disc herniation, prolapse or sequestration. CES may also be caused by smaller prolapses in the presence of spinal stenosis
  • Extruded disc herniation
  • Tumor lesions
  • Vertebral fractures
  • Canal stenoses
  • Infections
  • Surgical manipulation
  • Spinal anesthesia
  • Ankylosing spondylitis
  • Gunfire wounds
Illustration of large central disk herniation: A, Axial view. B, Sagittal view of lumbar spine | Lemma MA, Herzka AS, Tortolani PJ, Carbone JJ: Cauda equina syndrome secondary to lumbar disk prolapse, in Vaccaro A, Betz RB, Zeidman SM [eds]: Principles and Practice of Spine Surgery. Philadelphia, PA: Mosby, 2003, pp 347-353.

Clinical features

Patients with CES may present with a varying combination of signs and symptoms, including low back pain, groin and perineal pain, bilateral sciatica, lower extremity weakness, hypoflexia or areflexia, sensory deficits, perineal hypoesthesia or saddle anesthesia, and loss of bowel or bladder function.

Bladder dysfunction:

Early bladder dysfunction can be subtle and involve difficulty initiating the urinary stream. Dysfunction may then progress to urinary retention and eventually overflow incontinence.

Low back pain (LBP):

Characteristically severe , but it may be resolving or even absent in patients with delayed presentation.
  • Unilateral/bilateral sciatica
  • Saddle anesthesia (late sign): Dense sensory loss involving the perineum, buttocks, and posteromedial thighs
Illustration of saddle anesthesia. The S5, S4, and S3 nerves provide sensory innervation to the rectum, perineum, and inner thigh. | Spector, Leo R. MD; Madigan, Luke MD; Rhyne, Alfred MD; Darden, Bruce II MD; Kim, David MD Cauda Equina Syndrome, Journal of the American Academy of Orthopaedic Surgeons: August 2008 – Volume 16 – Issue 8 – p 471-479 Illustration of saddle anesthesia. The S5, S4, and S3 nerves provide sensory innervation to the rectum, perineum, and inner thigh.

Red flag signs:

  • Severe low back pain (LBP)
  • Sciatica (unilateral/bilateral)
  • Saddle and/or genital sensory disturbance
  • Bladder, bowel and sexual dysfunction

Diagnosis

The clinical history and the neurological examination lead to the need for diagnostic confirmation through complementary exams such as computed tomography (CT) and the gold standard, magnetic resonance imaging (MRI)

Physical examination:

Physical examination of patients with suspected CES must include a detailed examination of the sacral nerve roots.
  • Pinprick sensation testing in perianal region (S2-S4 dermatomes), perineum, and posterior thigh
  • Digital rectal examination: Assess tone and voluntary contracture of external anal sphincter. Decreased rectal tone is often an early finding in a patient with CES
  • Anal wink test
  • Bulbocavernosus reflex: Segmental polysynaptic reflex with crossover in the sacral spinal cord (S1-3). The reflex is performed by applying pressure to the glans penis or clitoris and/or traction on the Foley catheter. A normal response involves contraction of the anal sphincter.
Illustration of the bulbocavernosus reflex. Stimulation of the glans penis or gentle traction on the Foley catheter to stimulate the bladder will cause contraction of the rectal/anal sphincter. | Spector, Leo R. MD; Madigan, Luke MD; Rhyne, Alfred MD; Darden, Bruce II MD; Kim, David MD Cauda Equina Syndrome, Journal of the American Academy of Orthopaedic Surgeons: August 2008 – Volume 16 – Issue 8 – p 471-479

MRI:

gold standard for determining compression topography and etiology.8
Images from a patient who presented with the acute onset of back and bilateral leg pain and urinary incontinence. Axial (A) and sagittal (B) T2-weighted MRI scans of large central disk herniation at the L4-L5 level. C, Clinical photograph of disk material removed from patient. | Spector, Leo R. MD; Madigan, Luke MD; Rhyne, Alfred MD; Darden, Bruce II MD; Kim, David MD Cauda Equina Syndrome, Journal of the American Academy of Orthopaedic Surgeons: August 2008 – Volume 16 – Issue 8 – p 471-479

Differential diagnosis:

  • Conus medullaris syndrome (CMS): Compressive damage at T12-L2
    • CES: Compression of cauda equina (L1-L5)

Management

Surgical decompression:

Treatment of choice, if performed as early as possible, reduces neurological damage and improves prognosis

Summary:

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