Anesthesia for Spine Surgery

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Anesthesia for Spine Surgery

• Irene P. Osborn, M.D.
• Mount Sinai Medical Center
• New York, NY

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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

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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
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Changing times
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General Indications for Spine Surgery

• Neurologic dysfunction (compression)
• Structural instability
• Pathologic lesions
• Deformity
• Pain

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Spinal Cord Anatomy

•   Structure
•   Blood supply
• Autoregulation?

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Normal C-Spine Films
Lateral view
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Typical Pathologies

• Disc lesions
• Spinal canal stenosis
• Tumors
• Trauma

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Spinal Cord Injury Incidence/ Etiology

• 10, 000 new cases/year in US
• Malesgt females
• Causes
• MVA- 40-50
• Falls- 20
• Recreational activities- 7-15
• violence

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Cervical Spine Injury

• Occurs in 10 of head-injured patients
• Suspect when patient is flaccid, has
  diaphragmatic breathing, hypotension, bradycardia
• Minimize head movement during airway management
• In-line stabilization, rather than in-line
  traction, during laryngoscopy

Criswell JC, et al Anaesthesia 1994 49900-903
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Suspected Cervical Spine Injury

• Neck pain
• Neurologic symptoms, signs
• Unconscious
• Mechanism of injury
• Intoxication
• Spondylosis, rhumatoid arthritis
• Significant head injury, facial fractures

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Secondary Injury

• Activation of biochemical, enzymatic and
  microvascular
• Hemorrhagic necrosis, edema, inflammation
• Vascular stasis, decreased spinal cord blood
  flow, ischemic cell death

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Anesthetic management acute SCI

• Airway evaluation
• Neurologic evaluation
• Pulmonary evaluation
• Cardiac evaluation and resuscitation

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Neurologic DeteriorationAssociated with Airway
Management in a Cervical Spine-Injured Patient

• Hastings RH, Kelly SD
• Anesthesiology vol 78580, 1993

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Details

• Unrecognized C-spine injury
• Pt became quadriplegic after mask ventilation,
  repeated laryngoscopy and eventually
  cricothyroidotmy

Hastings, Anesthesiology 1993
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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 951175

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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
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Cervical spine motion a fluoroscopic comparison
during intubation with lighted stylet,
GlideScope, and Macintosh laryngoscope.

• Turkstra et al.
• Anesth Analg 2005 101 9105

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Tracheal intubation in patients with cervical
spine immobilizationa comparison of the
Airwayscope, LMA CTrach, and theMacintosh
laryngoscopes

• M. A. Malik, R. Subramaniam, S. Churasia1, C. H.
  Maharaj, B. H. Harteland J. G. Laffey

BJA 2009
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Cervical Disc Airway Strategies

• Talk to patient
• H/O extremity weakness/tingling
• Elicited symptoms with movement
• Neutral position is best

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Conditions associated with risk of cervical spine
pathology

• Downs syndrome
• Rheumatoid arthritis
• Ankylosing spondylitis
• Psoriatic arthritis
• Trauma

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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
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Factor Leading To Possible Higher Incidence of
RLN Injury
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Risk Factors for Postoperative Airway Compromise

• Duration of surgery
• Amount of blood transfusion
• Obesity, airway pressure
• Operations of greater than 4 cervical levels or
  involving C2

Epstein NE. J Neurosurg 94185 2001
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Anesthetic Technique

• Supine induction
• Maintenance with any combination of opioids,
  muscle relaxants, volatile agents
• Careful prone positioning

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Thorocolumbar Spine Disease

• Anterior or lateral pathology
• Multiple spine segments
• Scoliosis, tumors, traumatic fractures
• Potential large intraoperative blood loss

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Methods of Reducing Blood Loss and Limiting
Homologous Transfusions

• Proper positioning to reduce intraabdominal
  pressure
• Surgical hemostasis
• Deliberate hemodilution (?)
• Preoperative donation of autologous blood

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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)

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Prone Position Surgery

• Despite induced hypotension, some patients
  continue to bleed
• Pressure on the abdominal contents may be
  transmitted to the inferior vena cava and to the
  epidural venous system, causing increased bleeding

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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)

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The Effect of Patient Positioning on
Intraabdominal Pressure and Blood Loss in Spinal
Surgery

• CK Park
• Anesth Analg 200091552

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Wilson Frame

• Maintains flexed position for spinal surgery
• Intrabdominal pressure may be increased if
  supporting pads are not properly placed

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Blood loss during spinal surgery

• Group 1
• Blood loss (ml) 878
• of patients transfused 5
• Fluid replacement 2175 ml
• Operating time (min) 136

• Group 2
• Blood loss (ml) 436
• of patients transfused 1
• Fluid replacement 1865 ml
• Operating time (min) 134

Park Anesth Analg 200091
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Conclusions

• 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

Park Anesth Analg 200091
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Jackson Table

• Frame based table
• Allows abdomen and chest to hang freely
• May allow 180 degree rotation

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Lumbar spine surgery

• Preoperative pain/disability
• Intraoperative positioning
• Anesthetic technique
• Blood loss
• Postoperative pain management

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Support Devices Head Neck

• Surgical pillow/ foam donut, C-shaped face piece,
  horseshoe head rest, Prone Positioner, Prone View
  Helmet.

C-Shaped Face Piece
Prone Positioner

• Mayfield tongs most stable recommended in
  cervical disc disease

Horseshoe Head Rest
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Ischemic Optic Neuropathy

• Rare but increasing
• Decreased perfusion
• Increased venous pressure
• Increased external pressure
• Decreased oxygen carrying capacity

Williams, et al. Anesth Analg 1995 801018
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Injuries Eye

• Corneal abrasions
• Orbital edema
• Postoperative visual loss ( POVL)
• Rare unclear etiology
• ASA Closed Claims Project 12 management of
  anesthesiologists frequently implicated
• ASA Professional Liability Committee created the
  POVL Registry 13 in 1999

12 ASA Closed Claims Project http//www.asaclosedc
laims.org/ 13 American Society of
Anesthesiologists Task Force on Perioperative
Blindness Practice advisory for perioperative
visual loss associated with spine surgery a
report by the American Society
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POVL Registry

• Goal Identify risk factors associated with POVL
• Retrospective analysis of patients who reported
  visual loss lt 7 days postop

CRAO 11
Unknown 9
CARDIAC 9
VASCULAR 5
SPINE 72
PION 60
AION 20
ORTHO. 4
MISC. 10
Distribution of cases from the ASA POVL Registry
Distribution of 93 ophthalmic lesions associated
with POVL after spine surgery
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POVL
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Visual loss in spine surgeries 85 Ischemic Optic
Neuropathy (ION) 11 Central retinal artery
occlusion (CRAO) 4 Other Diagnoses
www.asaclosedclaims.org
Overview
Major Risks
MAC
Medication
Pain Management
Equipment
Visual Loss
Premiums
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Visual loss in spine surgeries 85 Ischemic Optic
Neuropathy (ION) 11 Central retinal artery
occlusion (CRAO) 4 Other Diagnoses
CRAO can result from pressure on the globe.
www.asaclosedclaims.org
Overview
Major Risks
MAC
Medication
Pain Management
Equipment
Visual Loss
Premiums
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Over two-thirds of cases reported to the POVL
Registry were related to spine surgery in the
prone position.
Lee LA, et al. The American Society of
Anesthesiologist Postoperative Visual Loss
Registry Analysis of 93 Spine Surgery Cases with
Postoperative Visual Loss. Anesthesiology. 2006
Oct in press.
www.asaclosedclaims.org
Overview
Major Risks
MAC
Medication
Pain Management
Equipment
Visual Loss
Premiums
52
Ischemic optic neuropathy was the most common
(89) cause of visual loss after spine surgery in
the prone position.
Lee LA, et al. The American Society of
Anesthesiologist Postoperative Visual Loss
Registry Analysis of 93 Spine Surgery Cases with
Postoperative Visual Loss. Anesthesiology. 2006
Oct in press.
www.asaclosedclaims.org
Overview
Major Risks
MAC
Medication
Pain Management
Equipment
Visual Loss
Premiums
53
In 96 of prone position spine cases, at least
one of the following was present

• 1000 ml estimatedblood loss
• 6 hours anesthetic duration

Lee LA, et al. The American Society of
Anesthesiologist Postoperative Visual Loss
Registry Analysis of 93 Spine Surgery Cases with
Postoperative Visual Loss. Anesthesiology. 2006
Oct in press.
www.asaclosedclaims.org
Overview
Major Risks
MAC
Medication
Pain Management
Equipment
Visual Loss
Premiums
54
Postoperative Vision Loss- Risk Factors

• Atherosclerotic disease
• Hypotension
• Anemia
• Excessive blood loss
• Long duration of surgery
• Head dependent positioning

Cheng MA Neurosurgery 46625, 2000
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Cardiovascular Support

• Maintain MAP above 70 mmHg
• Fluid management- blood crystalloid
• Pressors if needed

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Spine Surgery- Monitoring

• Routine
• Arterial line
• CVP/ PA catheter
• Neurophysiologic

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Monitoring the Spinal Cord

• SSEP
• MEP
• Wake up test
• EMG

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Indications for SSEPs

• Spinal instrumentation
• Scoliosis correction
• Spinal cord operations
• Aortic surgery

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Spine surgery Times of Increased Risk

• Spinal distraction
• Sublaminar wiring
• Induced hypotension
• Inadvertent cord compression
• Certain instrumentation (Lugue rods)
• Ligation of segmental arteries

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Anatomy of Spinal Tracts
Dorsal / Posterior
Ventral / Anterior
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Need For Concurrent MEP 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 199685566?7
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SSEP
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Loss of SSEP MEP
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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

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Anesthetic Considerations

• Patients often on chronic pain medication
• Hypotension may occur with acute blood loss
• Dexmedetomidine
• Use perioperatively
• May decrease narcotic use
• Hemodynamic stability
• Patients comfortable postoperatively

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Pain management strategies

• IV PCA
• Multimodal therapy
• Epidural opioids (catheter placed by surgeon)
• Cooperation with pain service

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Lumbar spine surgery

• Performed by neurosurgeons and orthopedics
• Minimally invasive techniques

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The ProSeal laryngeal mask airway in prone
patients a retrospective audit of 245 patients

• Patients positioned prone for induction
• Mask ventilation followed prone insertion
• Digital insertion in 237 pts, GEB technique in 8
  pts
• No complications- ONLY for experienced
  practitioners!
• Anesth Intensive Care 200735

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Caveats for prone LMAs

• Have good technique
• Avoid light anesthesia
• Position carefully and confirm placement tests
• Have stretcher available (just in case!)

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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