Dr. Kevin Yip

Dr Kevin Yip
Orthopaedic Surgeon
MBBS(UK), FRCS(EDIN), FAM(SING), FHKCOS(ORTHO)

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Cervical Spine Trauma: Dislocation and Subluxation

Basics
Description
  • 11,000 cases annually require surgery.
  • Average hospital stay: 9.4 days  ; a prolonged stay partly attributable to delay in diagnosing vertebral injuries (frequently missed)
  • Careful trauma-patient evaluation, increased understanding of injury patterns, and advanced imaging and treatment have decreased the morbidity and mortality associated with spinal column injuries  .
  • Classification:
    • The Denis 3-column theory  :
      • To determine vertebral fracture stability
      • Unstable fracture: Disruption of 2 columns
    • The Ferguson-Allen classification :
      • Based on the mechanism of injury
      • 7 categories: Compressive flexion (teardrop
      • fractures), vertical compression (burst fractures), distractive flexion (dislocations), compressive extension, distractive extension, lateral flexion, and miscellaneous cervical spine flexion
General Prevention
  • Seat belts and head rests on car seats
  • Possibly air bags
  • Strict cervical spine immobilization for all trauma patients
Incidence
  • Up to 75% of fractures of the vertebral column occur in the cervical spine.
  • 5-10% of blunt trauma patients have cervical spine injuries.
  • Serious diving accidents have a 50% incidence of cervical spine injury.
Risk Factors
Young males 18-25 years old
 
Genetics
  • Many skeletal dysplasias predisposing to traumatic injuries have a genetic basis, and some atraumatic instabilities are associated with a genetic predisposition.
    • Down syndrome is associated with a chromosomal disorder (trisomy 21).
    • Rheumatoid arthritis has a genetic predisposition, which seems to be associated with certain HLA markers.
  • Traumatic cervical dislocations have no genetic predisposition.
Etiology
  • Traumatic:
    • Motor vehicle collision
    • Diving in shallow water
    • Blunt trauma
  • Atraumatic:
    • Rheumatoid arthritis
    • Down syndrome
    • Skeletal dysplasias
Associated Conditions
  • Neurogenic shock
  • Head injury
  • Cervical spine fractures
  • Chest and abdominal trauma
  • Extremity trauma
Diagnosis
Signs and Symptoms
  • Neck pain after trauma
  • Occasionally, neck deformity, especially in rotatory subluxations or unilateral facet dislocations
  • Persistent asymmetric posturing or head tilt may indicate cervical subluxation or dislocation.
  • Neurologic injury may take the form of weakness, numbness, bowel or bladder incontinence, complete quadriplegia, or 1 of the incomplete spinal cord injury syndromes (Brown-sequard, central cord, anterior cord, posterior cord).
Physical Exam
  • All trauma evaluations begin with assessment of airway, breathing, and circulation.
  • Evaluation of the cervical spine should begin only after the patient is hemodynamically stable and life-threatening injuries have been ruled out.
  • Initial radiographs of the cervical spine, chest, and pelvis are useful in prioritizing therapy.
  • The initial neurologic examination (with the patient in a neck collar) requires careful documentation, including time of injury, and time and details of field and hospital examinations.
    • Sensory examination: Evaluate dermatomes, light touch, pin prick, temperature, and perianal sensation.
    • Motor examination:
      • Upper extremities: Grade the deltoids, triceps, biceps, wrist flexors and extensors, finger abductors and adductors, and grip strength.
      • Lower extremities: Test the iliopsoas, quadriceps, hamstrings, hip abductors/ adductors, tibialis anterior, extensor hallucis longus, and gastrocnemius-soleus complex.
      • Grade each muscle on a 0-5-point scale.
    • Do not use phrases such as “move everything” or “feel everything” because the physical examination provides a temporal sequence for a potentially evolving neurologic injury.
    • Rectal examination: Performed by the spine surgeon to assess tone, volitional control, and sensation to light touch and pin prick.
  • Examine the head and neck for tenderness and pain on motion.
    • If painful, immobilize the head and neck until adequate physical/radiologic examinations.
  • Suggested motor checkpoints:
    • C4: Diaphragm
    • C5: Deltoid and elbow flexors
    • C6: Wrist extensors
    • C7: Elbow extensors
    • C8: Finger flexors (profundus)
    • T1: Intrinsics (finger abductors)
    • L2: Hip flexors
    • L3: Knee extensors
    • L4: Ankle dorsiflexors
    • L5: Great toe extensors
    • S1: Ankle plantar flexors
    • S4-5: Voluntary anal contraction
  • Suggested sensory checkpoints:
    • C2: Occiput
    • C4: Tip of shoulder
    • C5: Regimental patch (lateral shoulder)
    • C6: Thumb
    • C7: Long finger
    • C8: Little finger
    • T1: Medial epicondyle
    • T4: Nipples
    • T10: Umbilicus
    • L1: Groin
    • L3: Patella
    • L4: Medial malleolus
    • L5: Great toe and first web space.
    • S1: Lateral heel
    • S2: Popliteal fossa
    • S3: Ischial tuberosity
    • S4-5: Perianal
Tests
Lab
  • Estimated lung vital capacity of at least 20% of predicted is necessary.
  • If vital capacity is <20% or 1,000 mL, a tracheostomy may be required.
Imaging
  • Radiographic evaluation of the cervical spine:
    • For any potentially neurologic injury
    • The AP view allows evaluation of the interspinous distance, alignment, and symmetry of uncovertebral joints.
    • Lateral view:
      • Most important view
      • Can detect approximately 82% of injuries to the cervical vertebrae.
      • The C7-T1 junction must be visualized adequately because injuries at this level are not uncommon.
      • If this level cannot be visualized, a swimmer’s view (arm abducted over the head and body slightly rotated) may be useful.
      • If C7-T1 still is not visualized, a CT scan at that level is necessary.
    • The open-mouth view is excellent for visualizing the dens and the overhanging lateral masses, but its acquisition frequently is limited by associated pain and the high degree of patient cooperation required.
    • Oblique views are excellent for visualizing the neural foramen and lamina, but their use in the trauma situation is controversial and generally is not a part of the trauma series.
    • Patient pain, cervical spine tenderness, or neurologic symptoms: Possible ligamentous injury even with negative radiographs
      • Lateral flexion-extension views may be indicated to evaluate for dynamic instability of the cervical vertebrae.
  • CT:
    • Evaluates any bony abnormalities
    • Usually obtained if injury is questionable on standard cervical spine radiographs
    • Standard of care for evaluation of any loss of middle column height
    • Planar reconstructions can be very valuable in surgical planning.
  • MRI:
    • Evaluates soft-tissue, pathologic, and ligamentous injuries
    • Also useful for evaluating neurologic deficits that cannot be explained radiographically
    • May be necessary for uncooperative or obtunded patients
Differential Diagnosis
  • Pseudosubluxation (other than normal <3 mm at C2 in children)
  • Cervical spine fractures with instability
  • Injuries at multiple levels
  • Muscular torticollis
Treatment
General Measures
  • Resuscitation and emergency measures:
    • Airway, breathing, and circulation
    • Strict immobilization during extraction and transportation (and intubation if necessary)
  • Emergency department assessment:
    • Complete (with neurologic) assessment
    • Full radiographic evaluation
  • Emergency treatment:
    • Traction for reduction of dislocations (MRI for facet dislocations)
    • Methylprednisolone:
      • Start within 8 hours of spinal cord injury to help preserve neuronal structures.
      • Dose: A 30-mg/kg bolus intravenously followed by 5.4 mg/kg/h for 23 hours
    • Surgery for irreducible dislocations with neurologic deficit and deterioration
  • For stable injuries, immobilization may be necessary for a short period.
  • The treatment of unstable injuries may vary from immobilization to surgical stabilization.
Activity
After the dislocation is stabilized, activity can be begun and advanced gradually.
 
Special Therapy
Radiotherapy
  • Decreases tumor size and burden in patients with pathologic thoracolumbar fractures
Physical Therapy
  • Important role in mobilizing spinal injury patients and for those with neurologic injury
  • May be helpful after healing to treat residual pain and stiffness
  • Wheelchairs are individualized to the patient.
  • Lower extremity bracing and orthotics for upper extremity function may be beneficial.
Surgery
  • Occipitocervical dissociation requires an occiput-to-C2 posterior fusion/instrumentation.
  • Atlantoaxial instability should include bracing for children and those with <7 mm of translation in flexion and fusion for patients with >7 mm of persistent translation.
  • Hangman’s fracture-dislocation or traumatic spondylolisthesis:
    • Can be treated with closed reduction and a Minerva cast in children
    • Halo immobilization or posterior open reduction and stabilization may be necessary, depending on the type of fracture.
  • Facet dislocations may require open reduction and stabilization for failed closed reduction.
Follow-up
Patients with neurologic injuries require long-term rehabilitation, including education, bladder and bowel program, family education, physical and occupational therapy, and psychologic counseling.
 
Prognosis
  • Prognosis depends on injury severity.
    • Neurologically intact patients with low-energy injuries have excellent recovery.
    • Patients with neurologic injury have major issues, potentially requiring alteration in their personal and professional lives.
Complications
  • Surgical complications: Infection, neurologic injury, pseudarthrosis, chronic pain, and disability
  • Other complications include neurologic injury, spinal deformity, chronic pain, and skin problems from pressure points on neck braces.
Patient Monitoring
Neurologic monitoring (including somatosensory-evoked potentials and motor monitoring) during reduction maneuvers and surgery may increase the safety of the procedure.

Miscellaneous
Codes
ICD9-CM
  • 839.01 C-1 dislocation
  • 839.02 C-2 dislocation
  • 839.03 C-3 dislocation
  • 839.04 C-4 dislocation
  • 839.05 C-5 dislocation
  • 839.06 C-6 dislocation
  • 839.07 C-7 dislocation
Patient Teaching
  • Skin care and positioning to prevent flexion contractures
  • Education to prevent pressure ulceration, respiratory, and urinary infections
FAQ
Q: What imaging modality is considered a part of the trauma series in evaluating a patient?
A: Lateral cervical spine, AP chest, and AP pelvis radiographs.
 
 
Q: What is the last vertebrae that must be visualized for an adequate C-spine lateral radiograph?
A: C7-T1 junction.

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