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Anesthesia for Spine Surgery Irene P. Osborn, M.D. Mount Sinai Medical Center New York, NY 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?
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Anesthesia for Spine Surgery Irene P. Osborn, M.D. Mount Sinai Medical Center New York, NY
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
General Indications for Spine Surgery • Neurologic dysfunction (compression) • Structural instability • Pathologic lesions • Deformity • Pain
Spinal Cord Anatomy • Structure • Blood supply • Autoregulation?
Normal C-Spine Films Lateral view
Typical Pathologies • Disc lesions • Spinal canal stenosis • Tumors • Trauma
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, bradycardia • Minimize head movement during airway management • In-line stabilization, rather than 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 • 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
Unrecognized C-spine injury Pt became quadriplegic after mask ventilation, repeated laryngoscopy and eventually cricothyroidotmy Details 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
70 cases 67 under general anesthesia 2 awake/topicalized 1 unconscious No new neurologic deficits Patients with Immobilized Cervical Spines 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 theMacintosh laryngoscopes M. A. Malik, R. Subramaniam, S. Churasia1, C. H. Maharaj, B. H. Harteland 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
Conditions associated with risk of cervical spine pathology • Down’s syndrome • Rheumatoid arthritis • Ankylosing spondylitis • Psoriatic arthritis • Trauma
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
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 94:185 2001
Anesthetic Technique • Supine induction • Maintenance with any combination of opioids, muscle relaxants, volatile agents • Careful prone positioning
Thorocolumbar Spine Disease • Anterior or lateral pathology • Multiple spine segments • Scoliosis, tumors, traumatic fractures • Potential large intraoperative blood loss
Methods of Reducing Blood Loss and Limiting Homologous Transfusions • Proper positioning to reduce intraabdominal pressure • Surgical hemostasis • Deliberate hemodilution (?) • Preoperative donation of autologous blood
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) Prone Position
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
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)
“The Effect of Patient Positioning on Intraabdominal Pressure and Blood Loss in Spinal Surgery” CK Park Anesth Analg 2000;91:552
Wilson Frame • Maintains flexed position for spinal surgery • Intrabdominal pressure may be increased if supporting pads are not properly placed
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 Blood loss during spinal surgery Park Anesth Analg 2000;91
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 2000;91
Jackson Table • Frame based table • Allows abdomen and chest to hang freely • May allow 180 degree rotation
Lumbar spine surgery • Preoperative pain/disability • Intraoperative positioning • Anesthetic technique • Blood loss • Postoperative pain management
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 • Mayfield tongs: most stable; recommended in cervical disc disease • Horseshoe Head Rest • Mayfield Tongs
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) • Rare; unclear etiology • ASA Closed Claims Project12 : management of anesthesiologists frequently implicated • ASA Professional Liability Committee created the POVL Registry 13 in 1999 12 ASA Closed Claims Project http://www.asaclosedclaims.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
POVL Registry • Goal: Identify risk factors associated with POVL • Retrospective analysis of patients who reported visual loss < 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
ASA Closed Claims Project Profound visual lossVision loss is usually unilateral. Vision loss is usually total. 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
ASA Closed Claims Project 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