The potential risk factors for POVL that are listed are: - Obesity - Long Prone Cases - Anemia - Pressure on the globe - Hypotension - Glaucoma Cataracts is not a risk factor for POVL.

1. Anesthesia for Spinal cord injury
and scoliosis
Atef Kamel
MD

2. Background
Anatomy & Physiology
Pathophysiology
Pharmacology
Anesthetic Technique & Management
Management of Complications
Case Study

3. Anatomy & Physiology

4. Anatomy and physiol

7. Blood Flow to the Spinal Cord
Anterior Spinal Artery (1)
Anterior 2/3 of spinal cord
Posterior Spinal Arteries (2)
posterior 1/3 of spinal cord
These 3 arteries depend on a network of
collateral vessels to provide adequate blood
supply to the spinal cord.

8. Artery of Adamkiewicz
arteria radicularis magna
Largest most consistent
radicular artery
Located in the
thoracolumbar region
(T5-L3)
Supplies blood to the ASA
(anterior 2/3 of cord)
Responsible for most of
the spinal cord blood flow
beneath its point of entry
If obstructed  Anterior
Artery Syndrome

9. Spinal Cord Blood Flow
Autoregulation determines the amount of blood
flow to the sp cd.
Limits: 50-150 mmHg. Outside these limits
pressure dependant.
Spinal cord blood flow increases when CO2
levels are high and decreases when CO2 levels
are low. (similar to cerebral blood flow)
Injury to the spinal cord alters both
autoregulation and CO2 responsiveness.

10. Pathophysiology

11. Spinal Cord Injury
Trauma  Partial or Complete transection of the cord
Transections above C 3-5 = Diaphragmatic innervention
(ventilator required for survival)
Transections above T 1 = Quadraplegia
Transections above L4 = Paraplegia
Most Common C 5-7 & T 12 - L 1
(least protected / most mobile)

12. Acute Spinal Cord Injury
Spinal shock may begin within an hour after injury and
last from several minutes to several months, after which
reflex activity gradually returns:
Flacid paralysis
Complete loss of reflex and sensory activity below level
of lesion.
Loss of vasomotor tone, CV instability, Hypotension,
Bradycardia, Venous pooling.
Paralytic ileus with distension
Hypothermia

13. Scoliosis
Lateral curvature of the
spine, usually accompanied
by rotation.
Cobb angle is a method
used to measure the
curvature.
The greater the angle, the
greater the progression and
severity of complications.

15. Causes of Scoliosis
Neuromuscular Scoliosis - the result of muscle
imbalance and lack of trunk control. (i.e. cerebral
palsy, muscular dystrophy, or leg length
discrepancy)
Congenital Scoliosis - the result of asymmetry of
the vertebrae secondary to congenital anomalies.
(i.e. hemivertebrae, failure of segmentation)
Idiopathic Scoliosis - no definite etiology.
Diagnosis of exclusion. Most common type
accounting for 80-85% of cases

16. Effects of scoliosis
 Increased curvature =
narrowing of thoracic
cage, which leads to
abnormal CV and Pulm
function.
 Increased curvature causes
increased co-morbidities
 Restrictive lung
disease, dyspnea on
exertion, pulmonary
hypertension, cor pulmonale
and alveolar hypoventilation.

17. Respiratory Abnormalities
Lung volumes reduced
Compliance decreased
Restrictive pattern
Abnormal V/Q
Shallow, rapid breathing
Alveolar hypoventilation
Hypoxemia

18. PROGRESSION OF RESPIRATORY DISEASE WITH
INCREASING DEGREE OF SCOLIOSIS
< 10 normal
> 25 increased PA pressures
> 40 surgery considered
> 65 restrictive lung disease
> 100 exertional dyspnoea
> 120 alveolar hypoventilation

19. NEUROMUSCULAR SCOLIOSIS – severe respiratory
dysfunction
weak resp muscles
ineffective cough, unable to clear secretions
incoordinate swallowing, impaired airway
defences
impaired central resp drive
exaggerated resp depressant effect of drugs
immobile, retain secretions
recurrent chest infections

20. CARDIOVASCULAR ABNORMALITIES
Pulmonary Hypertension
Chronic hypoxia
Reduced flow through compressed lung
Impaired development of pulm vasc bed
Cor Pulmonale
Cardiac Failure

21. Other Cardiovascular Associations
Idiopathic scoliosis - mitral valve
prolapse
Muscular dystrophy -
cardiomyopathy,
arrhythmias
Myotonia - dysrhythmias, conduction
abnormalities, mvp

22. Pharmacology

23. Spinal Cord Injury & Succinylcholine
Succinylcholine- Induced Hyperkalemia.
Safe to administer Succs within first 48 hours after
spinal cord injury.
Avoid Succs in all spinal cord injuries after 48 hours

24. Epidural Steroid Injections
 Methylprednisone 80 mg (smaller amounts
in diabetics who may be at increased risk for
formation of epidural abscess) is injected into
epidural space close to the nerve root.
 The addition of 3-4 mL of local anesthetic
(lidocaine) to the injected solution produces
analgesia, confirming proper drug placement

25. Epidural Steroid Injection

26. Epidural Steroid Injection (cont.)
Few pts get relief from repeated injections if first one
was unsuccessful.
Relief can last from weeks to months - injections are
repeated every 3-4 months.
Little risk of serious complications ; Aseptic
meningitis and bacterial meningitis
Adrenal Suppression may occur but recovers in 1-3
months.

27. High Dose Steroid Therapy
(methylprednisone)
Acute Spinal Cord Injury
Severe spine disease undergoing major spinal surgery.
Recommendation = bolus dose of 30 mg/kg over 15
minutes, then 5.4 mg/kg/hr for 23 hrs, within 8 hours of
injury.
If therapy is started 8 hours after injury, the duration of
the methylprednisone therapy should be continued for
48 hours
Pitfalls = Immunosuppression,wound infections & GI
bleeds.

28. Tricyclic Antidepressants
• Useful for chronic pain, producing analgesic
effect via inhibition of reuptake of serotonin and
norepinephrine.
• Other benefits include: normalization of sleep
patterns, reduction in anxiety and depression.

29. Anticonvulsants
May have some efficacy in treatment of
chronic pain syndromes
Chronic anticonvulsants lead to an
increased resistance to non-depolarizing
neuromuscular relaxants

30. Anesthetic Technique & Management

31. Management of Spinal Cord Injuries
Immediate management is critical.
Improper handling can cause further
damage and loss of functioning
Always assume there is a spinal cord
injury until it is ruled out
Immobilize
Prevent flexion, rotation or extension of
neck
Avoid twisting patient

32. Management cont’d
• Management is aimed at preventing
further injury and observing for
progression of neuro deficits
• Consists of emergency treatment
following an A-B-C-D-E sequence.

33. Airway Management
First priority.
Open airway with jaw-thrust maneuver.
Use bag-valve-mask device initially, if
necessary intubate.
High conc. of 02 will prevent bradycardia or
asystole for patients exhibiting signs of
neurogenic shock.

34. Breathing
Lesions above C5 level will cause partial to
complete diaphragmatic paralysis (diaphragm is
innervated at C3-5 levels).
Lesions at C5 and below will allow full
diaphragmatic movement, but intercostal muscles
(innervated at T1) and abdominal muscles
(innervated at T12) are affected.

35. Circulation
Cardiac output is affected by external or
internal hemorrhage and neurogenic
shock.
IV fluids
Blood transfusion
Vasopressors

36. Disability
Neurological Examination
Lateral C-Spine X-ray
CT scan
Search for other injuries:
abdominal, chest, …

37. Anesthesia Implications for
Acute Spinal Cord Transection
 In-line stabilization of neck. Consider fiberoptic
intubation, especially if cervical spine injury is suspected.
 Prepare for CV instability, position changes, mild blood
loss, ..
 Guard against hypothermia.
 Succinylcholine may be administered within the first 24
hrs of acute injury
 Blood flow (maintain perfusion pressure, normal CO2)
 SSEP, MEP, wake up test

38. Anesthesia Implications for
Chronic Spinal Cord Transection
Monitor for autonomic hyperreflexia. Have
rapid-acting vasodilators available.
Bradycardia / absence of compensatory
tachycardia (cardioaccelerators T1-4).
Use nondepolarizing muscle relaxants only.
Guard against hypothermia.
Position carefully (osteoporosis).

39. Autonomic Hyperreflexia
Sympathetic system reflex
response below the level of a
spinal cord transection.
At T5 or above.
After the resolution of
spinal shock.
Triggers : stimulation below
the level of injury.

41. Autonomic hyperreflexia
S/S = HTN, reflex
bradycardia, seizure, SAH, PE, VD/ flushing
above transection & VC/ pallor below
transection.
Treatment:
Remove noxious stimulus,
Raise head of bed,
Administer rapid-acting vasodilator
drugs.

42. Anesthesia for scoliosis

43. Pre-operative Evaluation
History & examination - type of scoliosis, assoc. problems (
neuromuscular, airway, GIT, MH, latex allergy), resp and
cardiac
CXR , ECG, Blood tests
Spine Xray – severity & location
Echo
Lung Function Testing (if severe deformity)
Lung volumes (>40% reduction ~ post-op complics)
Flow volume loop
ABG

44. Preoperative preparation
Clear chest infection .
Wake up test explaining.
Posibility of post operative mechanical
ventilation
Premedication: atropine?
 Heavy sedation should be avoided in severe
scoliosis.?

45. Anesthetic Problems associated with
Scoliosis Surgery
Problems related to the patient:
Respiratory , cardiovascular
neuromuscular abnormalities or
syndromes.

46. Problems related to the surgery
Prone position
Blood loss and third space loss: solution?
Lengthy operation
Preservation and monitoring of spinal
cord function.
Heat loss.??
Postoperative visual loss.

47. Monitoring
Routine monitors:
oximeter, ECG, capnography, esophageal
stethoscope and core body temp
Arterial catheter to monitor beat to beat
changes.
CVP
Urinary catheter
Blood loss and replacement are
monitored.
Patient’s position

48. Induction of anesthesia
Two large IV lines
Suxamethonium. is avoided in paralyzed
patients or neuromuscular etiology.
Intermediate non depolarizing ms. relaxent
like Atracurium or Rcuronium is used for
intubation and maintenance of relaxation.

49. Prone position

50. Prone position
Maintain alignment of head / neck, support
head in neutral position w/ pillow or head
holding device.
Avoid hyperextension of arms by tucking them
against the body or extending them <90
degrees alongside the head on armboards
Compression stockings to avoid the pooling of
blood.
Frequently examine
eyes, ears, chin, nose, shoulders, breasts, and
genitalia for areas of pressure.

51. Spinal Cord Protection
Methylprednisolone
Reestablish normotension, normooxia and normocarbia to avoid
secondary insult.
Instruct surgeon to decrease traction on spinal cord.
Monitoring of the spinal cord: wake up test, SSEP and MEPs

52. Post Op Visual Loss -POVL
Unkown Cause, may Risk Factors:
hypoperfusion +edema  Hypotension
+stretching of the optic  Anemia
nerve.  Glaucoma
Long prone cases  Preventative measures:
 Keep IV fluid to reasonable
Large amounts of IV level
fluid.  HCT > 27
 MAP >70 mmHg
 Avoid pressure on globe

53. SPINAL CORD MONITORING
The Wake Up Test:
 2 assisstants
 Monitors motor function, simple to
perform
Problems -
extubation/lines/hardware, air
embolism, awareness, false neg.
Containdications – paresis, uncoop.
Modified for use in small children
(withdrawal to tetanic stimulus)

54. SOMATOSENSORY EVOKED POTENTIALS
Continuous
Sensory tracts
Latency (> 0.2msecs)
Amplitude (> 50%
decrease)
Cortical or Spinal

55. MOTOR EVOKED POTENTIALS
MEP is basically an EMG potential
recorded over muscles in the hand or foot
in response to depolarization of the
motor cortex using transcranial stimulus.
MEP profoundly affected by anesthetic
agents, recordable only during TIVA
MEP cannot be recorded in the presence
of complete neuromuscular blockade.

56. Extubation of the patient
Extubation may be performed immediately
Extubation in the ICU

57. Indications for postoperative mechanical ventilation:
VC was < 30% of predicted.
Severe gas exchange abnormality (↑PaCO2).
Duchenne muscular dystrophy.
Severe CP.
Patient with congenital heart.
Severe face edema.
PaO2 on mask ↓70 mmHg
Respiratory rate > 35 breath /min.

58. Post operative care
Pulmonary care.
Fluid management.
Pain control. How?
Laboratory studies.

59. Case Study
29 ys male pt. 110 kg. 9 days s/p MVA
SCI. hx = asthma, donated one kidney.
Planned surgery is a C1-3 Cervical
fusion. dx: occipitoatlantal instability?

60. Pre Op
Monitors
Induction
Maintenance
Emergence
Post Op

61. Question
All of the following are potential risk factors for
POVL except for 2 of the following.
• A. Obesity
• B. Long Prone Cases
• C. Anemia
• D. Pressure on the globe
• E. Hypotension
• F. Glaucoma
• G. Cataracts

62. Question
• Paraplegia is the result of which of the following
injuries?
• A. Occlusion of the artery of adamkiewicz
• B. Spinal cord transection at C7
• C. Spinal cord transection at L2
• D. A & C are both correct
• E. All of the above are correct