Transcript Spinal Cord Injury

Anesthesia for Spine
Surgery
Sherif Anis, M.D
Ain Shams University
Cairo, Egypt
Lecture Goals
• Overview of modern concepts in
understanding of the spinal cord disease
• Review controversies in anesthesia for spine
surgery
• Provide strategies for improving patient care
Why spine?
• 29.9 million people reported
musculoskeletal impairments.
Back/spine was most frequent,
representing 51.7%. Impairment is
most prevalent in 45-64 year old group.
AAOS, Musculoskeletal
Conditions in the U.S., Feb
1992
Changing times
General Indications for Spine
Surgery
1. Spinal cord injury
2. Decompresive spine surgery due to
•
Trauma
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Tumor
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Degenerative disease (Spondylosis,
spondylolisthesis,
•
Spinal canal stenosis,Rheumatoid disease)
•
Structural deformity (Scoloisis)
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Prolapsed Disc
•
Infection, Vascular malformation
Spinal Cord Anatomy
•
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Structure
Blood supply
Normal C-Spine Films
AADI ≥ 5 mm = Cervical instability
Lateral view
Spinal Cord Injury: Incidence/
Etiology
• 10, 000 new
cases/year in US
• Males> females
• Causes:
MVA- 40-50%
Falls- 20%
Recreational activities7-15%
violence
Cervical Spine Injury
• Occurs in 10% of head-injured patients
• Suspect when patient is flaccid, has
diaphragmatic breathing, hypotension,
bradydysrythmias, LV dysfunction(Acute
SCI)
• Minimize head movement during airway
management by cervical collar
• In-line stabilization,in-line traction,
during laryngoscopy
Criswell JC, et al: Anaesthesia 1994; 49:900-903
Suspected Cervical Spine Injury
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Neck pain
Neurologic symptoms, signs
Unconscious
Mechanism of injury
Intoxication
Spondylosis, rhumatoid arthritis, Down
syndrome (Distruction of transverse
ligament and odontoid process).
• Significant head injury, facial fractures
Secondary Injury
• Activation of
biochemical,
enzymatic and
microvascular
• Hemorrhagic necrosis,
edema, inflammation
• Vascular stasis,
decreased spinal cord
blood flow, ischemic
cell death
Anesthetic management – acute
SCI
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Airway evaluation
Neurologic evaluation
Pulmonary evaluation
Cardiac evaluation and resuscitation
Neurologic Deterioration
Associated with Airway
Management in a Cervical SpineInjured Patient
Hastings RH, Kelly SD
Anesthesiology vol 78:580, 1993
Details
• Unrecognized Cspine injury
• Pt became
quadriplegic after
mask ventilation,
repeated
laryngoscopy and
eventually
cricothyroidotmy
Hastings, Anesthesiology 1993
Use of the Intubating LMAFastrach™ in 254 Patients with
Difficult to Manage Airways
Ferson DZ, Rosenblatt WH, Osborn I,
Ovassapian A.
Anesthesiology 2001 vol 95:1175
Patients with Immobilized
Cervical Spines
• 70 cases
• 67 under general
anesthesia
• 2 awake/topicalized
• 1 unconscious
• No new neurologic
deficits
Ferson et al,
Anesthesiology 2001
Cervical spine motion: a fluoroscopic
comparison during intubation with
lighted stylet, GlideScope, and
Macintosh laryngoscope.
Turkstra et al.
Anesth Analg 2005; 101: 910–5
Tracheal intubation in patients with
cervical spine immobilization:
a comparison of the Airwayscope, LMA
CTrach, and the
Macintosh laryngoscopes
M. A. Malik, R. Subramaniam, S.
Churasia1, C. H. Maharaj, B. H. Hartel
and J. G. Laffey
BJA 2009
Cervical Disc: Airway
Strategies
• Talk to patient
• H/O extremity
weakness/tingling
• Elicited symptoms
with movement
• Neutral position is
best
Anesthetic Technique
• Supine induction
• Maintenance with any
combination of
opioids, muscle
relaxants, volatile
agents
• Careful prone
positioning
• Careful sitting position
Anterior Cervical Approach
On the Incidence, Cause, and
Prevention of Recurrent Laryngeal
Nerve Palsies During Anterior Cervical
Spine Surgery
Apfelbaum RI, et al: Spine Volume 25(22), 15 November 2000, pp 2906-2912
Factor Leading To Possible Higher
Incidence of RLN Injury
Laterality
Right > Left
Levels
Lower Cervical Level
Multiple Levels
More Level Higher Incidence
ETT Pressure
Higher Pressure or Failure to Deflate
Postoperative Complications
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Cervical cord and brain stem edema
Neck and airway edema
Risk Factors:
Duration of surgery
Amount of blood transfusion
Obesity, airway pressure
Operations of greater than 4 cervical
levels or involving C2
Epstein NE. J Neurosurg
94:185 2001
Thorocolumbar Spine Disease
• Anterior or lateral
pathology
• Multiple spine segments
• Structural Scoliosis,
tumors, traumatic fractures
• Preop.
pain/disability/Medications
• Potential large
intraoperative blood loss
• Anesthetic technique
• Postoperative pain
management
Structural Scoliosis
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Idiopathic
Neuro-muscular (Neuropathic, Myopathic)
Congenital
Neurofiromatosis
Mesenchymal disorders (Marfan
Syndrome)
• Trauma
Methods of Reducing Blood Loss
and Limiting Homologous
Transfusions
• Proper positioning to reduce intraabdominal
pressure
• Surgical hemostasis
• Deliberate hemodilution (?)
• Preoperative donation of autologous blood
• Blood Salvage technique
• Deliberate Hypotension
Prone Position
• Restriction of
diaphragm
– by abdominal contents
– and weight of pt
against thorax
• Create restrictive
defect
• Increased peak
inspiratory pressure
(barotrauma)
• Obstruction of Inf
Vena Cava
– Decreases preload
– Increases perivertebral
venous pressure
• (prone may improve
oxygenation when
abdomen hangs freechest roll or frame)
Complications of Flexed Prone
Position
• Brachial plexus may be
stretched
• Ulnar nerve not properly
padded
• Eye damage from pressure
• Nose pressure
• Excessive compression to
inferior vena cava
(minimized by padding
under inf iliac spine and
chest rolls)
Wilson Frame
• Maintains flexed
position for spinal
surgery
• Horse-shoe head rest
• Proper position of the
head and easy
inspection of the face
& Eyes.
Support Devices – Head & Neck
• Surgical pillow/ foam
donut, C-shaped face
piece, horseshoe head
rest, Prone Positioner,
Prone View Helmet.
Prone Positioner
C-Shaped Face Piece
Horseshoe Head Rest
Mayfield Tongs
• Mayfield tongs: most
stable; recommended
in cervical disc disease
38
Jackson Table
• Frame based table
• Allows abdomen and
chest to hang freely
• May allow 180 degree
rotation
Blood loss during spinal surgery
• 15- 25 ml/Kg
• Type of procedure (AP fusion Luque rods into the
pelvis), Operation time
• Number of Spine segments.
• Duchenne myopathy
• Cerebral palsy
• Post-operative bleeding.
• TRALI
Park Anesth Analg 2000;91
• IAP and intraoperative blood loss were less
in the wide vs. narrow width of the Wilson
frame
• Blood loss per vertebra tended to increase
with an increase in IAP in the narrow pad
support
Ischemic Optic Neuropathy
• Rare but increasing
• Decreased perfusion
• Increased venous
pressure
• Increased external
pressure
• Decreased oxygen
carrying capacity
Williams, et al. Anesth Analg 1995 80:1018
Injuries: Eye
• Corneal abrasions
• Orbital edema
• Postoperative visual loss ( POVL)
43
POVL Registry
• Goal: Identify risk factors associated with POVL
• Retrospective analysis of patients who reported visual loss < 7
days postop
SPINE 72%
Distribution of cases from the
ASA POVL Registry
AION 20%
PION 60%
Distribution of 93 ophthalmic lesions
associated with POVL after spine surgery
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Postoperative Vision LossRisk Factors
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Atherosclerotic disease
Hypotension
Anemia
Excessive blood loss
Long duration of surgery
Head dependent positioning
Cheng MA Neurosurgery
46:625, 2000
POVL
Ischemic Optic
Neuropathy (ION)
Central Retinal Artery
Occlusion (CRAO)
Etiology
Intraop ↓ BP
Prolonged surgery
↑ Blood loss
↑ Crystalloid infusion
Direct external pressure
Emboli
Mechanism
Ischemia
Orbital edema → stretch
and compression of ON
↓Ocular perfusion pressure
Clinical
Features
Painless
Bilateral
↓Light perception
↓ Visual fields
Painless
Unilateral
Periorbital swelling or
ecchymosis
46
Cardiovascular Support
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Maintain SCPP=MAP-CSFP
Maintain MAP above 70 mmHg
Fluid management- blood & crystalloid
“Pressors” if needed
Spine Surgery- Monitoring
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Routine
Arterial line
CVP/ PA catheter
Neurophysiologic
Monitoring the Spinal Cord
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SSEP
MEP
Wake up test
EMG
Indications for SSEP’s
• Spinal
instrumentation
• Scoliosis correction
• Spinal cord
operations
• Aortic surgery
Spine surgery: Times of
Increased Risk
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Spinal distraction
Sublaminar wiring
Induced hypotension
Inadvertent cord compression
Certain instrumentation (Lugue rods)
Ligation of segmental arteries
High risk patients
• Severe rigid deformity Cobb angle ≥ 120ͦ
• Congenital scoliosis with intra-spinal
anomalies.
• Post infectious
• Pre-existing neurological deficits
MEP
SSEP
Dorsal /
Posterior
SSEP
MEP
Ventral /
Anterior
“Damage in the territory of the anterior
spinal artery might theoretically occur
without causing significant impairment of
the dorsal sensory tracts, particularly when
the spine is approached from the anterior
side.”
May DM, Jones SJ, Crockard HA.
Somatosensory evoked potential monitoring in cervical surgery:
identification of pre- and intraoperative risk factors associated with neurological deterioration.
J Neurosurg 1996;85:566ﾐ7
Factors affecting SSEP
• All Anesthetic agents except NMB
(Narcotics least effect)
• Hypotension below cerebral autoregulation
• Hypothermia
• Hypoxemia
• Hemodilution and low HCT levels
SSEP
Loss of SSEP & MEP
Caveats for MEP monitoring
• You CAN intubate
with non-depolarizing
agent (there will be
time for it to wear off)
• When closing,
administer NMB to
allow decrease of
hypnotic agents
Wake up Test
• 1 or 2 assistants available
• N2O-Narcotic-Relaxant technique, better
TIVA
• Rare use of Naloxone 0.3-0.5 µgm/Kg
• No reversal of NMB (3 twitches on TOF)
• Complications: Extubation, Recall, M.I,
Dislodgement of instrumentations, Air
embolism
Anesthetic Considerations
• Hypotension may occur with acute blood loss
Dexmedetomidine:
• Use peri-operatively
• May decrease narcotic use
• Hemodynamic stability
• Patients comfortable postoperatively
MgSO4:
• NMDA antagonist
Methyl-prednisolone:
• Better in post traumatic patients (6-8 hours)
When would you Extubate??
• Post-operative MV with severe restrictive
VC ≤ 30%, High PCo2
• Duchenne Myopathy, Familial
dysautonomia, Cerebral palsy
• Criteria for extubation: VC ≥ 10ml/Kg,
Vt ≥ 5 ml/ Kg,
RR ≤ 30
-ve insp. Force ≥ -30cmH2o
Pain management strategies
(Positive attitude in Negative Situations)
• IV PCA
• Multimodal therapy
• Epidural opioids
(catheter placed by
surgeon)
• Cooperation with pain
service
• Incentive spirometery
• Cough & deep
breathing
Conclusions
• Understand and appreciate the anatomy and
physiology of the spinal cord
• Communicate with your surgeons
• Explore new techniques but remember to
perfuse and monitor the patient
THANK YOU