Anesthesia for Spine Surgery Sherif Anis, M.D Ain Shams University Cairo, Egypt.
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Transcript of Anesthesia for Spine Surgery Sherif Anis, M.D Ain Shams University Cairo, Egypt.
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• Tumor • Degenerative disease (Spondylosis,
spondylolisthesis, • Spinal canal stenosis,Rheumatoid disease)• Structural deformity (Scoloisis)• Prolapsed Disc• Infection, Vascular malformation
Spinal Cord Anatomy
• Structure• Blood supply
Normal C-Spine FilmsAADI ≥ 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 activities- 7-15%
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• 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
• Airway evaluation
• Neurologic evaluation
• Pulmonary evaluation
• Cardiac evaluation and resuscitation
Neurologic DeteriorationAssociated with Airway
Management in a Cervical Spine-Injured Patient
Hastings RH, Kelly SD
Anesthesiology vol 78:580, 1993
Details
• Unrecognized C-spine injury
• Pt became quadriplegic after mask ventilation, repeated laryngoscopy and eventually cricothyroidotmy
Hastings, Anesthesiology 1993
Use of the Intubating LMA-Fastrach™ 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
Laterality Right > Left
LevelsLower Cervical
Level
Multiple Levels More Level Higher Incidence
ETT Pressure Higher Pressure or Failure to Deflate
Factor Leading To Possible Higher Incidence of RLN Injury
Postoperative Complications• 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
• 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 free- chest 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
38
• Surgical pillow/ foam donut, C-shaped face piece, horseshoe head rest, Prone Positioner, Prone View Helmet. C-Shaped Face Piece
Horseshoe Head Rest Mayfield Tongs
• Mayfield tongs: most stable; recommended in cervical disc disease
Prone Positioner
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
43
• Corneal abrasions
• Orbital edema
• Postoperative visual loss ( POVL)
POVL Registry
44
SPINE 72%
MISC. 10%ORTHO. 4%
VASCULAR 5%
CARDIAC 9%
Distribution of cases from the ASA POVL Registry
• Goal: Identify risk factors associated with POVL
• Retrospective analysis of patients who reported visual loss < 7 days postop
PION 60%AION 20%
Unknow
n
9%
CR
AO
11%
Distribution of 93 ophthalmic lesions associated with POVL after spine surgery
Postoperative Vision Loss- Risk Factors
• Atherosclerotic disease
• Hypotension
• Anemia
• Excessive blood loss
• Long duration of surgery
• Head dependent positioning
Cheng MA Neurosurgery 46:625, 2000
POVL
46
Ischemic Optic Neuropathy (ION)
Central Retinal Artery Occlusion (CRAO)
Etiology Intraop ↓ BPProlonged surgery↑ Blood loss↑ Crystalloid infusion
Direct external pressureEmboli
Mechanism IschemiaOrbital edema → stretch and compression of ON
↓Ocular perfusion pressure
Clinical Features
PainlessBilateral↓Light perception↓ Visual fields
PainlessUnilateralPeriorbital swelling or ecchymosis
Cardiovascular Support
• Maintain SCPP=MAP-CSFP
• Maintain MAP above 70 mmHg
• Fluid management- blood & crystalloid
• “Pressors” if needed
Spine Surgery- Monitoring
• Routine
• Arterial line
• CVP/ PA catheter
• Neurophysiologic
Monitoring the Spinal Cord
• 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
• 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 ≥ 120Q
• Congenital scoliosis with intra-spinal anomalies.
• Post infectious
• Pre-existing neurological deficits
Dorsal /Posterior
Ventral /Anterior
MEP
MEP
SSEP
SSEP
“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 lossDexmedetomidine:• Use peri-operatively• May decrease narcotic use• Hemodynamic stability• Patients comfortable postoperativelyMgSO4: • NMDA antagonistMethyl-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