Cervical Spine injury

Cervical Spine injury 

Etiology

1. Traumatic Causes (≈80%)

• Motor vehicle accidents (most common)
• Falls (especially in elderly)
• Sports injuries
• Violence (gunshot, stab wounds)
• Industrial accidents

2. Non-traumatic Causes

• Tumors (intramedullary/extramedullary)
• Infections (TB, epidural abscess)
• Ischemia/infarction (e.g., aortic surgery)
• Degenerative diseases (cervical spondylotic myelopathy)
• Inflammatory (transverse myelitis, MS)

Anatomy 

Region	Vertebral Levels	Function Loss
Cervical (C1–C8)	Neck	Quadriplegia, respiratory failure (C3–C5 affects diaphragm)
Thoracic (T1–T12)	Chest	Paraplegia, loss of intercostal function
Lumbar (L1–L5)	Lower back	Paraplegia, bladder/bowel involvement
Sacral (S1–S5)	Pelvis	Bowel, bladder, sexual dysfunction

Neurological Level of Injury

The neurological level of injury (NLI) is defined as the most caudal spinal cord segment in which motor and sensory functions remain intact. Clinically, this corresponds to the lowest level demonstrating at least antigravity muscle power (Medical Research Council grade ≥3/5) together with preserved sensation to both light touch and pinprick.

It is important to recognize that the neurological level does not always correspond precisely to the anatomical site of spinal column injury identified on imaging, as spinal cord dysfunction may extend above or below the radiographic level of injury.

Example 1: Cervical Spine Injury

A patient is involved in a road traffic accident.

CT scan:Fracture-dislocation at C5 vertebra

Neurological examination:

• Deltoid (C5): 5/5
• Biceps (C5): 5/5
• Wrist extensors (C6): 3/5
• Triceps (C7): 0/5
• Normal sensation up to C6 dermatome
• Sensation absent below C6

Neurological level = C6

Although the fracture is at the C5 vertebral level, the neurological level is C6 because C6 is the lowest segment with preserved motor and sensory function.

Example 2: Thoracic Injury

MRI:Burst fracture of T10 vertebra

Clinical examination:

• Normal sensation to T8 dermatome
• Sensation impaired from T9 downward
• Lower limb weakness

Neurological level = T8

Here, the anatomical injury is at T10 vertebra, but the neurological level is T8 because the spinal cord dysfunction extends above the vertebral injury.

Mechanism of Injury

Primary Injury

• Occurs at the moment of trauma
• Direct mechanical disruption of axons, neurons, and blood vessels

Secondary Injury

• Minutes to days after primary insult
• Spinal cord edema often increases over 3-6 days following the initial injury.
• Mediated by:
  
  • Ischemia and hypoxia
  • Excitotoxicity (glutamate release)
  • Free radical formation
  • Inflammatory cytokines
  • Edema → ↑ Intramedullary pressure → further ischemia

 Classification Systems

1. Anatomical Classification

• Complete SCI – No motor/sensory function below lesion, including S4–S5
• Incomplete SCI – Some sensory/motor sparing below lesion

2. ASIA Impairment Scale (American Spinal Injury Association)

Grade	Description
A	Complete – no motor/sensory below level, including sacral
B	Sensory incomplete – sensory preserved, no motor below
C	Motor incomplete – motor preserved, but <50% of key muscles have grade ≥3
D	Motor incomplete – ≥50% of key muscles have grade ≥3
E	Normal – motor and sensory normal

Syndromic Classification (Incomplete Injuries)

Syndrome	Mechanism	Clinical Features
Central Cord Syndrome	Hyperextension injury (elderly, cervical spondylosis)	Greater weakness in upper limbs > lower limbs, bladder dysfunction, variable sensory loss
Anterior Cord Syndrome	Flexion or anterior spinal artery infarct	Loss of motor, pain, and temperature below lesion; preserved proprioception
Posterior Cord Syndrome	Rare (posterior spinal artery infarct, B12 deficiency)	Loss of proprioception and vibration, preserved motor and pain/temp
Brown-Sequard Syndrome	Hemisection (stab, gunshot)	Ipsilateral motor + proprioception loss, contralateral pain/temp loss
Conus Medullaris Syndrome	Injury at L1 level	Early bladder, bowel, sexual dysfunction, symmetrical motor weakness
Cauda Equina Syndrome	Injury to lumbosacral roots	Asymmetric weakness, areflexia, saddle anesthesia, severe radicular pain

Clinical Features

1. Motor and Sensory Loss

• Below level of lesion
• Determined by dermatomal and myotomal mapping

2. Autonomic Dysfunction

• Neurogenic shock (acute phase)
  
  • Hypotension, bradycardia, warm dry skin
  • Loss of sympathetic tone (T1–L2)
  • spinal cord damage above the T6 level will cause a selective deficit of sympathetic innervation of the heart (causing the heart to receive unopposed parasympathetic activity from the vagus nerve).
• Autonomic dysreflexia (chronic phase)
  
  • Lesions above T6
  • Triggered by bladder distension, bowel impaction, pain
  • Severe hypertension with reflex bradycardia

3. Respiratory Compromise

• C3–C5: Diaphragmatic paralysis (phrenic nerve)
• C5–T6: Weak intercostal muscles

4. Bladder and Bowel Dysfunction

• Above sacral segments: Spastic (reflex) bladder
• Below sacral segments: Atonic (flaccid) bladder

Neurogenic vs Spinal Shock

Feature	Spinal Shock	Neurogenic Shock
Cause	Loss of spinal reflexes below lesion(reversible impairment)	Loss of sympathetic tone
Onset	Immediately after injury	Usually in cervical/high thoracic(above T6)-selective removal of sympathetic
Duration	Days to weeks(it has 4 phases)	Hours to days
BP	Variable(Normal or low)	Hypotension(due to vasodilation)
HR	Normal or variable	Bradycardia>>normal HR
Other	Phase 1 (0–24 hours) Areflexia/Hyporeflexia Features:Complete loss of reflexes,Flaccid paralysis,Loss of autonomic activity. Phase 2 (1–3 days) Initial Reflex Return Earliest reflexes return:Delayed plantar response,Bulbocavernosus reflex (BCR) Phase 3 (1–4 weeks) Early Hyperreflexia Features:Reflexes become brisk,Muscle tone increases Phase 4 (1–12 months) Spasticity andHyperreflexia Features:Hypertonia,Clonus,Spastic paralysis.	Cutaneous vasodilation(patient feel warm but it leads to hypothermia) Priapism dry extremities
Reflexes	Absent	Intact above lesion
End point	Return of bulbocavernosus reflex	Hemodynamic stabilization
Management	no specific treatment for spinal shock itself.Management focuses on acute SCI.	vasopressors +/- inotropes i.e (e.g., epinephrine monotherapy, or a combination of norepinephrine plus dobutamine

Diagnostic Evaluation

Investigation	Purpose
X-ray (spine)	Initial screening for fracture/dislocation
CT scan	Bony detail, canal compromise
MRI (spine)	Gold standard for cord edema, hemorrhage, compression
Neurological exam (ASIA)	Baseline grading
Urodynamic study	For chronic bladder dysfunction

Clinical Clearance of Cervical Spine: NEXUS vs Canadian C-Spine Rule

Both are validated decision-making tools to safely avoid unnecessary imaging in trauma patients who are alert, cooperative, and hemodynamically stable.

1. NEXUS Criteria (National Emergency X-Radiography Utilization Study)

Purpose:

To identify low-risk patients in whom cervical spine injury can be excluded clinically — no imaging required if all criteria are negative.

NEXUS Low-Risk Criteria

Imaging is NOT needed if the patient has all five of the following:

Criterion	Explanation
1. No midline cervical tenderness	No pain on palpation over cervical spine spinous processes
2. No focal neurological deficit	No motor or sensory deficit
3. Normal level of alertness	GCS = 15, oriented ×3
4. No intoxication	No alcohol or drug influence affecting evaluation
5. No painful distracting injury	No major injury (e.g., long bone fracture, visceral injury) diverting attention from neck pain

 If all 5 criteria are met → No imaging required.
 If any one is positive → CT cervical spine (preferred).

Performance

• Sensitivity: ~99.6%
• Specificity: ~12%
• Advantages: Simple, quick, easy to apply
• Limitations: Low specificity → over-imaging possible

2. Canadian C-Spine Rule (CCR)

Purpose:To identify trauma patients who require imaging after blunt trauma to the head/neck.

Applies to:

• Alert (GCS 15)
• Stable vital signs
• Blunt trauma mechanism

Step 1: Any High-Risk Factor → Imaging Needed

High-Risk Factor	Example
Age ≥ 65 years	Elderly fall, minor trauma
Dangerous mechanism	Fall > 1 m / 5 stairs, axial load (diving), high-speed MVC (>100 km/h), rollover, ejection
Paresthesias in extremities	Sensory symptoms indicating cord involvement

If yes → imaging required
If no → proceed to Step 2

Step 2: Any Low-Risk Factor → Safe Assessment of ROM

Low-Risk Factor	Meaning
Simple rear-end MVC	Excluding high-speed, bus/large truck, rollover
Sitting position in ED	Not supine
Ambulatory at any time	Before or after trauma
Delayed onset of neck pain	Not immediate pain
Absence of midline tenderness	No spinal tenderness

If none of these low-risk factors → imaging required.
If any one present → proceed to Step 3.

Step 3: Active Neck Rotation Test

Ask the patient to actively rotate the neck 45° to both sides.

Finding	Interpretation
Able to rotate 45° both sides	No imaging needed
Unable to rotate	Imaging required

Performance

• Sensitivity: 99–100%
• Specificity: 42–45% (higher than NEXUS)
• Advantages: More specific, reduces unnecessary imaging
• Limitations: Slightly complex, not for <16 years or GCS <15

Emergency Management (ATLS-Based)

1. Airway, Breathing, Circulation (ABC)

• Assume C-spine injury in all trauma until ruled out
• Airway: Jaw thrust (avoid head tilt–chin lift)
• Intubation: Rapid sequence with Manual inline stabilization

MILS

Two commonly used techniques include:

• The assistant may kneel beside the operator and stabilize the head by holding the mastoid regions or supporting the occiput with both hands.
• Alternatively, the assistant may stand at the head end facing the operator, placing both hands along the sides of the patient’s head while resting the forearms on the patient’s chest to maintain alignment.
• Once the airway has been successfully secured, MILS should be discontinued and replaced with definitive cervical spine immobilization using a rigid cervical collar along with lateral supports (foam blocks or sandbags) and securing straps across the forehead and chin.
• For emergency tracheal intubation, the use of a bougie-assisted technique is recommended as the preferred first-line approach, whether direct laryngoscopy or videolaryngoscopy is employed. An endotracheal tube mounted on a stylet may be used when a bougie is unavailable or unsuccessful.
• Awake fibre-optic intubation remains a valuable alternative in selected patients, particularly when cervical spine movement must be minimized. However, its use requires appropriate equipment, operator expertise, patient cooperation, and sufficient time; therefore, it is generally unsuitable in true airway emergencies.

Current evidence suggests that neurological worsening attributable solely to oral endotracheal intubation in patients with unstable cervical spine injuries is exceedingly uncommon. When neurological deterioration occurs after injury, it is often related to progression of the original spinal cord insult, edema, vascular compromise, or ascending myelopathy rather than airway manipulation itself.

• Breathing: Oxygen, mechanical ventilation if C3–C5 lesion
• Circulation: Avoid hypotension (MAP > 85 mmHg)

2. Immobilization

• Hard cervical collar (Philadelphia)—because of this and to avoid even lateral rotation of neck —Avoid CVC placement in internal jugular vein.
• If possible try to Avoid removing  soft Collar while Intubating.hard collars should not be used during airway management.hard collars also limit mouth opening
• Spine board with logroll precautions

3. Pharmacologic Management

• High-dose methylprednisolone – Controversial
  
  • NASCIS II suggested benefit if started within 8 hours
  • Current guidelines (AANS, 2021): Not routinely recommended due to infection, GI bleed, hyperglycemia.

4. Hemodynamic Goals

• Maintain MAP 85–90 mmHg for first 7 days
• Avoid hypoxia and anemia (maintain Hb >10 g/dL)
• Norepinephrine first line. However, for patients with neurogenic shock and bradycardia, the use of epinephrine could be used.

5. Definitive Management

• Early surgical decompression (ideally within 24 hours)
  
  • Indications:
    
    • Cord compression on imaging
    • Incomplete lesion with progression
    • Instability or fracture dislocation
• Stabilisation with instrumentation/fusion
• Avoid neck movement in ICU/WARD(in post-op period) even after Stabilisation until neurosurgeon advice to remove collar.

 ICU Management

Problem	Management
Ventilatory support	May need prolonged ventilation therefore Early tracheostomy
Vasopressor support	Norepinephrine preferred for MAP target
DVT prophylaxis	Start within <72 hours of injury.For patients undergoing surgery, DVT prophylaxis can usually be started within 24 hours of surgery, but this decision should be made jointly with the surgical team.
Pressure sore prevention	Regular repositioning, air mattress
Bladder management	Intermittent or indwelling catheterization
Bowel management	Stool softeners, digital stimulation
Nutritional support	High-protein diet for wound healing
Physiotherapy & rehabilitation	To prevent contractures, maintain mobility
Psychological support	Depression and anxiety are common
Temperature regulation	Poikilothermia due to loss of sympathetic control
Autonomic dysreflexia	Treat with sitting up, remove triggers, give nifedipine/labetalol
Infection risk	Especially pneumonia and UTI
Spasticity control	Baclofen, tizanidine
Pain management	Neuropathic (gabapentin, pregabalin)

Prognostic Indicators

Good Prognosis	Poor Prognosis
Incomplete lesion	Complete lesion
Early return of reflexes	No improvement in 72 hours
Early decompression	Associated polytrauma
Younger age	Severe cord hemorrhage on MRI

Dermatomal and Myotomal Mapping

Term	Definition
Dermatome	An area of skin supplied by sensory fibers from a single spinal nerve root.
Myotome	A group of muscles innervated by motor fibers from a single spinal nerve root.

Clinical Use:

• In spinal cord injury, assessing sensory (dermatome) and motor (myotome) levels helps determine neurological level of lesion and ASIA grading.

 Dermatome Map (Sensory Distribution)

Spinal Level	Area of Sensory Supply	Bedside Clinical Landmark
C1	No dermatome (no cutaneous branch)	—
C2	Back of head, upper neck	Occipital protuberance
C3	Side of neck	Supraclavicular fossa
C4	Shoulder region, clavicle	Over acromioclavicular joint
C5	Lateral upper arm	Over deltoid (lateral upper arm)
C6	Lateral forearm, thumb	Tip of thumb
C7	Middle finger	Tip of middle finger
C8	Little finger, medial forearm	Tip of little finger
T1	Medial upper arm	Medial side of antecubital fossa
T2	Axilla, upper inner arm	Apex of axilla
T3–T6	Upper chest	T4 = Nipple line
T7–T9	Lower chest, upper abdomen	T10 = Umbilicus
T11–T12	Lower abdomen, groin	T12 = Inguinal ligament
L1	Upper anterior thigh	Just below inguinal ligament
L2	Mid-anterior thigh	Mid-thigh
L3	Medial knee	Medial femoral condyle
L4	Medial leg and ankle	Medial malleolus
L5	Lateral leg, dorsum of foot	Dorsum of foot, big toe web space
S1	Lateral foot, sole, heel	Lateral malleolus, little toe
S2	Posterior thigh and calf	Popliteal fossa
S3–S5	Perineum	S3–S5: saddle area, perianal region

 Myotome Map (Motor Distribution)

Spinal Level	Main Muscles Tested	Motor Function / Movement	Key Reflex
C1–C2	Neck flexors and extensors	Flexion/extension of neck	—
C3	Trapezius, levator scapulae	Shoulder elevation	—
C4	Diaphragm (phrenic nerve)	Inspiration	—
C5	Deltoid, biceps	Shoulder abduction, elbow flexion	Biceps jerk
C6	Biceps, wrist extensors	Elbow flexion, wrist extension	Brachioradialis jerk
C7	Triceps, wrist flexors	Elbow extension, wrist flexion	Triceps jerk
C8	Finger flexors, small hand muscles	Finger flexion/grip	—
T1	Interossei, intrinsic hand muscles	Finger abduction/adduction	—
T2–T12	Intercostals, abdominal muscles	Trunk stability, respiration	—
L1–L2	Iliopsoas	Hip flexion	—
L3	Quadriceps	Knee extension	Patellar (knee) jerk
L4	Tibialis anterior	Ankle dorsiflexion	Knee jerk (also L3)
L5	Extensor hallucis longus, gluteus medius	Great toe extension, hip abduction	—
S1	Gastrocnemius, soleus	Plantar flexion	Ankle jerk
S2	Hamstrings	Knee flexion	—
S3–S5	Anal sphincter, pelvic floor	Anal tone, bladder/bowel control	Anal wink / bulbocavernosus reflex

Clinical Correlation Table

Spinal Level	Motor Deficit	Sensory Loss	Reflex Change
C5	Weak shoulder abduction, elbow flexion	Lateral arm	↓ Biceps reflex
C6	Weak wrist extension	Thumb, lateral forearm	↓ Brachioradialis
C7	Weak elbow extension	Middle finger	↓ Triceps reflex
C8	Weak grip	Little finger, medial forearm	—
L3–L4	Weak knee extension	Medial leg	↓ Knee jerk
L5	Weak great toe extension	Dorsum of foot	—
S1	Weak plantar flexion	Lateral foot	↓ Ankle jerk

Clinical Application in Spinal Cord Injury (SCI)

• Determine sensory level (lowest dermatome with intact sensation)
• Determine motor level (lowest myotome with MRC ≥3/5)
• The neurological level of injury = lower of sensory and motor levels.
• Complete lesion: No S4–S5 sensory or motor function (no anal sensation or tone)
• Incomplete lesion: Any sacral sparing (e.g., preserved perianal sensation or voluntary anal contraction)

• Always test sensation symmetrically (light touch + pinprick).
• Use MRC grading for motor power (0–5 scale).
• Examine deep tendon reflexes and anal tone.
• Document level as:
  e.g. C6 AIS B → C6 level, sensory incomplete.

References 

1. Irwin and Rippe’s Intensive Care Medicine. Spinal cord injury and neurocritical care chapters.
2. Oh’s Intensive Care Manual. Neurologic emergencies and spinal cord injury.
3. ISCCM Textbook Of Critical Care 2026