0%
Topic
Review Topic
0
0
N/A
N/A
Questions
10
0
0
0%
0%
Evidence
8
0
0
0%
0%
Videos / Pods
3
0%
0%
Cases
1
Topic
https://upload.orthobullets.com/topic/2065/images/large disc herniation copy.jpg
https://upload.orthobullets.com/topic/2065/images/saddle.jpg
Summary
  • Cauda equina syndrome is caused by severe compression of the nerve roots in the thecal sac of the lumbar spine, most commonly due to an acute lumbar disc herniation
  • Presumptive diagnosis is made by characteristic presenting symptoms of saddle-like paresthesias and confirmed with emergent MRI.
  • Treatment involves surgical decompression within 48 hours 
Science
  • Epidemiology
    • incidence
      • 1-6% of lumbar disc herniations
    • demographics
      • more common in males
      • 4th decade of life
    • location
      • most commonly occurs at the L4-5 level
  • Pathophysiology
    • pathoanatomy
      • space-occupying lesion within lumbosacral canal
        • disc herniation (most common)
        • spinal stenosis
        • tumors
        • trauma (retropulsion of fracture fragment, dislocation or collapse)
          • zone III sacral fractures
          • lumbar burst fractures
        • spinal epidural hematoma
          • can potentially occur after neuraxial anesthesia and early DVT prophylaxis
        • epidural abscess
        • developmental spondylolisthesis
      • iatrogenic causes
        • gelfoam
        • epidural fat graft
        • spinal manipulation
        • excessive dural retraction
    • pathobiology
      • mechanical compression decreases nutrient delivery to the nerve root
        • decreased blood flow
        • decreased CSF diffusion
      • intraneural compartment syndrome
        • venous congestion and intraneural edema from hypoperfusion injury further decreases arterial perfusion pressures
        • nerve root ischemia follows
  • Associated conditions
    • orthopedic conditions
      • spondylolisthesis
      • lumbar burst fractures
      • sacral fractures
      • epidural hematoma
    • medical conditions
      • deep vein thrombosis (DVT)
        • is a well known complication after spinal trauma or spine surgery
          • often DVT prophylaxis is held out of concern for epidural hematoma 
            • antiplatelet medications can be safely resumed approximately 48-72 hours post-op from spinal procedures
  • Prognosis
    • natural history
      • progressive weakness of the lower extremities
      • loss of bowel and bladder function
    • prognostic variables
      • presence of saddle anesthesia or bladder dysfunction is associated with worse outcomes
      • surgical decompression after 48 hours is associated with worse outcomes
Anatomy
  • Spinal cord 
    • conus medullaris
      • tapered, terminal end of the spinal cord
      • terminates at T12 or L1 vertebral body
    • filum terminale
      • non-neural, fibrous extension of the conus medullaris that attaches to the coccyx
    • cauda equina (horse's tail) 
      • collection of L1-S5 peripheral nerves within the lumbar canal
      • compression considered to cause lower motor neuron lesions 
        • roots only covered with endoneurium
          • sensitive to compression
  • Bladder
    • receives innervation from 
      • parasympathetic nervous system (pelvic splanchnic nerves and the inferior hypogastric plexus) 
        • promotes urination
          • contraction of the detrusor urinae muscles
          • relaxation of the internal sphincter
      • sympathetic plexus (hypogastric plexus)
        • promotes urinary retention
          • relaxation of the detrusor urinae muscles
          • contraction of the internal sphincter
    • external sphincter of the bladder is controlled by the pudendal nerve
      • voluntary control
    • lower motor neuron lesions of cauda equina will interrupt the nerves forming the bladder reflex arcs
      • unable to sense bladder filling
      • unable to initiate appropriate muscle contraction and relaxation
Presentation
  • History
    • might have history of lifting heavy object with lumbar spine in flexed position
  • Symptoms 
    • common symptoms
      • back pain
        • often initial presenting symptom
      • unilateral or bilateral leg pain is the most common presenting symptom after back pain  
      • saddle anesthesia  
      • impotence
      • sensorimotor loss in lower extremity
      • neurogenic bladder dysfunction
        • disruption of bladder contraction and sensation leads to urinary retention and eventually to overflow incontinence 
    • bowel dysfunction is rare
  • Physical exam
    • inspection
      • lower extremity muscle atrophy with insidious presentations (e.g. spinal stenosis)
    • palpation
      • lower back pain/tenderness is not a distinguishing feature
      • palpation of the bladder for urinary retention
    • neurovascular examination
      • bilateral or unilateral lower extremity weakness and sensory disturbances
      • decreased or absent lower extremity reflexes
      • reduced or absent sensation to pinprick in the perianal region (S2-S4 dermatomes), perineum, and posterior thigh
        • must distinguish between pinprick and light touch sensation
      • decreased rectal tone or voluntary contracture
    • provocative tests
      • diminished or absent bulbocavernosus reflex 
      • diminished or absent anal wink test 
        • reflex contraction of the external anal sphincter upon pinprick stimulation of skin around the anus
Imaging
  • Radiographs
    • recommended views
      • AP, lateral 
        • flexion/extension views in non-traumatic cases
    • findings
      • burst fractures
      • high-grade developmental spondylolisthesis (intact-lamina)
  • MRI
    • indications
      • study of choice to evaluate neurologic compression   
        • must be performed emergently if cauda equina syndrome is suspected
    • findings
      • often reveals large central disc herniation with complete spinal canal obliteration
      • presence of spinal stenosis
      • epidural hematoma
      • epidural abscess
  • CT myelography
    • indications
      • study of choice if patient unable to undergo MRI 
        • e.g. pacemaker, MRI-incompatible implants
    • findings
      • sagittal and axial reconstructions can reveal space-occupying lesion
Studies
  • Laboratory
    • CBC, ESR, CRP
      • concern for infectious etiology (i.e. epidural abscess)
  • Urodynamic studies
    • preoperative postvoid residual volumes (PVR)
      • recommended to be obtained prior to decompression but not at delay of decompression
      • normal postvoid residual volume is less than 50 to 100 mL
        • PVR values < 200 ml with a 97% negative predictive value for cauda equina syndrome
    • postoperative postvoid residual volume
      • assessment for return of bladder function
Treatment
  • Operative
    • surgical decompression within 48 hours  
      • indications
        • significant suspicion for CES
        • severity of symptoms will increase the urgency of surgical decompression
      • techniques
        • microdiskectomy 
        • lumbar decompression (laminectomy)
        • laminectomy with instrumentation fusion (rarely indicated)
      • outcomes
        • studies have shown improved outcomes in bowel and bladder function and resolution of motor and sensory deficits when decompression performed within 48 hours of the onset of symptoms 
          • residual bladder deficits may persist despite successful decompression 
        • motor recovery may continue up to 1 year post-op
        • bladder function may continue to improve up to 16 months post-op
        • no comparison studies between microdiskectomy alone and wide decompression combined with microdiskectomy
Techniques
  • Microdiskectomy (laminotomy, unilateral medial facetectomy & diskectomy)
    • indications
      • massive soft disc herniation in younger patient with minimal degenerative changes
    • approach
      • 2 cm paramedian incision made on one side of pathology
      • expose lamina from spinous process to facet joint
    • laminotomy
      • 5-10mm laminotomy made over area of disc herniation
    • medial facetectomy
      • minimal facetectomy made with kerrison
    • ligamenum flavum window
      • cleft in ligametum flavum made and lateral section removed
    • anulotomy
      • dural retraction
      • removal of offending disc material
        • micropituitary rongeur 
        • irrigation through a metal cannula
        • ensure disc material is thoroughly removed
  • Lumbar decompression (laminectomy)  
    • indications
      • older patient with degenerative changes included hypertrophic ligamentum flavum, lateral recesss stenosis
    • approach
      • can be performed with PLC preserving undercutting approach or spinous process resection 
    • technique
      • bilateral laminectomy
      • bilateral ligamentaum flavum resection
      • bilateral medial facetectomyunilateral diskectomy
    • advantages
      • wide laminectomy performed
        • decreases the amount of dural retraction
        • greater degree of decompression
        • better visualization of the dura
      • removal of offending disc fragment
      • can be performed with instrumentation
        • presence of instability
          • high-grade spondylolisthesis
          • insidious-type cauda equina syndrome in the context of degenerative spondylolisthesis
Complications
  • Non-operative
    • sexual dysfunction
      • risk factors
        • delay in surgical decompression
      • prognosis
        • recovery may be prolonged over several years
        • worse prognosis for recovery in older patients
    • urinary dysfunction 
      • risk factors
        • delay in surgical decompression
      • treatment
        • may require permanent catheterization
    • chronic pain
    • persistent leg weaknes
  • Operative
    • dural tear
      • incidence
        • occurs in 1-4% of cases
      • treatment
        • treatment involves primary repair of the dura with or without dural graft of fat grafting
          • prevents pseudomeningocele and durocutaneous fistula sequalae
        • postoperative bed rest for 4-7 days
        • may require a lumbar drain
        • no difference in outcomes if adequately treated
    • epidural fibrosis
      • cause of postoperative back and leg pain
        • presents about 3 months post-op
      • treatment
        • responds poorly to re-exploration
        • evaluates with gadolinium-enhanced MRI
          • differentiates from recurrent HNP
    • wound infection
      • incidence
        • approximately 1% of cases
      • risk factors
        • increased risk with diabetics
    • vascular injury
      • incidence
        • rare complication
      • risk factors
        • perforation of the ALL with curettes during disc removal
      • treatment
        • requires immediate resuscitation and intraoperative vascular consultation
        • mortality up to 50%
    • iatrogenic segmental instability
    • nerve root injury

Please rate topic.

Average 3.8 of 65 Ratings

Questions (10)

(SBQ12SP.72) A 32-year-old male presents with back pain and saddle anesthesia after lifting a heavy object. Figures A and B show T-2 MRI sagittal and axial images, respectively. Which of the following most accurately lists the additional symptoms or physical exam findings this patient may have from most common to least common? Tested Concept

QID: 3770
FIGURES:
1

Leg pain > urinary retention > urinary incontinence

58%

(1626/2797)

2

Urinary retention > leg pain > absent ankle jerk

6%

(157/2797)

3

Urinary retention > leg pain > urinary incontinence

6%

(157/2797)

4

Leg pain > urinary incontinence > urinary retention

12%

(342/2797)

5

Reduced rectal tone > urinary retention > leg pain

18%

(493/2797)

L 4 B

Select Answer to see Preferred Response

(SBQ12SP.38) A 32-year-old woman presents to the emergency department with two days of worsening back and leg pain after feeling a sharp pop in her low back after an episode of coughing. She complains of numbness in her perianal region and bilateral buttocks that she notices when wiping herself with toilet paper after urinating. She also reports she is having difficulty urinating and had some episodes of incontinence. She complains of bilateral leg pain that is worse on the left in the region of the anterolateral calf. On physical exam she has weakness to big toe extension of 3/5 and is unable to walk on her heels with the toes elevated. MRI of her spine is shown in figures A through C. After surgical intervention, which of her symptoms is least likely to improve? Tested Concept

QID: 3736
FIGURES:
1

Big toe extension weakness

13%

(527/3970)

2

Bladder dysfuction

66%

(2624/3970)

3

Loss of perianal sensation

6%

(221/3970)

4

Numbness in the left foot

8%

(318/3970)

5

Burning pain in left leg

6%

(258/3970)

L 4 B

Select Answer to see Preferred Response

Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK

(SAE09SN.15) A 56-year-old man with a history of chronic lower back pain from lumbar spondylosis reports a 2-day history of acute incapacitating back pain. He denies any history of acute trauma, although he reports the pain starting after a coughing spell. He also reports difficulty urinating and some fecal incontinence. Examination reveals generalized lower extremity weakness, saddle paresthesia, hyporeflexia in the lower extremities, and loss of rectal tone. What is the most appropriate management at this time? Tested Concept

QID: 6803
1

Immediate MRI of the lumbar spine

98%

(572/583)

2

General reassurance, anti-inflammatory drugs, and an early home exercise program

0%

(0/583)

3

Immediate radiographs of the lumbar spine and pain medications with 2 days of bed rest if the radiographs are normal

1%

(3/583)

4

Office caudal epidural steroid injection with follow-up in 1 week

0%

(0/583)

5

Outpatient MRI of the lumbar spine with follow-up in 1 week for test results

0%

(1/583)

L 1 E

Select Answer to see Preferred Response

Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK

(OBQ04.101) A 49-year-old male presents with saddle anesthesia, lower extremity weakness, and urinary retention. When must surgical decompression be done to improve bladder and motor recovery? Tested Concept

QID: 1206
1

less than 24 hours after symptom onset

37%

(1319/3613)

2

less than 48 hours after symptom onset

62%

(2226/3613)

3

less than 60 hours after symptom onset

1%

(24/3613)

4

less than one week after symptom onset

1%

(20/3613)

5

less than two weeks after symptom onset

0%

(5/3613)

L 3 C

Select Answer to see Preferred Response

Evidence (19)
VIDEOS & PODCASTS (4)
CASES (1)
EXPERT COMMENTS (14)
Private Note