Scoliosis & Anesthesia Considerations Reed Tenney, SRNA NURA 815 University of Kansas

Outline Introduction Assessment Diagnostics Treatment Anesthesia procedures Anesthetic considerations Related complications & management Summary

Introduction Scoliosis is a deformity of the spine with lateral curvature and rotation of the vertebrae and ribcage. Idiopathic – 75-90% of cases 10-25% of cases associated with: Neuromuscular diseases Congenital abnormalities ie .heart disease Trauma Mesenchymal disorders Surgery Indicated for Cobb angle > 50 deg. Untreated can lead to death by 45 years http://www.coreconcepts.com.sg/mcr/wp-content/uploads/2009/10/Cobb-Angle1.jpg

Introduction (cont.) Kyphoscoliosis is characterized by anterior flexion and lateral curvature. Idiopathic – 80% of cases. Occurring often during late childhood Times of rapid growth 4 per 1000 population Females 4x more prone than males Other causative factors. Diseases of neuromuscular system Poliomyelitis Cerebral palsy Muscular dystrophy Spinal curvature > 40 degrees considered severe. http://healthool.com/wp-content/uploads/2013/08/kyphosis-pictures.jpg

Assessment Physical considerations: Restrictive lung disease r/t lung tissue compression. Pulmonary Hypertension r/t ↑ PVR from compressed lung vasculature and hypoxemia. Core pulmonale from ↑ workload of right heart / ↑PVR DOE r/t ↓ lung volumes. Decreased VC. PaCO2 normal, may rapidly decompensate with insult to system, ie. URI, trauma etc. Ineffective cough → frequently pulmonary infections.

Diagnostics (pre op) ABG PFT (mainly VC) Exercise tolerance tests Airway assessment Baseline Hgb & Hct T&S Cardiac and Pulmonary work up

Barash et al.(2009) figure 53-2

Treatment Non-surgical (early onset idiopathic) Bracing Risser Casting http://www.medscape.com/viewarticle/723932_6 Young children may need GA to tolerate casting. Airway! Airway! Airway! Decreased compliance from cast setting (↑ PIP ↓ Vt) may require emergent opening of cast. Dedicated person holding ETT T/O procedure (multiple repositioning of pt.) Communication is key

Treatment Surgical / Spinal fusion and instrumentation Anterior approach Lateral position Removal of one or more ribs Manipulate diaphragm OLV with DLT if ↑ T8 Associated with greater respiratory insufficiency than prone Posterior approach Prone https://www2.aofoundation.org/wps/portal/!ut/p/a0/04_Sj9CPykssy0xPLMnMz0vMAfGjzOKN_A0M3D2DDbz9_UMMDRyDXQ3dw9wMDAzMjfULsh0VAbWjLW0!/?approach=Anterior%20to%20lumbar%20spine&bone=Spine&classification=55- Adolescent%20Idiopathic%20Scoliosis%2C%20Lenke%205&implantstype=&method=&redfix_url=&segment=Deformity&showPage=approach&treatment=&contentUrl=/srg/55/04-Approaches/A001b_AnteriorToLumbarSpine.jsp

Anesthesia Procedures Arterial line +/- Central line- monitoring CVP, useful for evacuation of VAE 2 Good IV’s Possible difficult intubation DLT OLV

Anesthetic Considerations Pre-Op VC of < 40% of predicted likely requires post operative ventilator support (Past Board Question) Potential for elevated blood loss - T &S current with blood ready to go. Cell Saver Hypothermia Controlled hypotension Prone positioning precautions POVL VAE monitor for S/S

Anesthetic Considerations MEP Avoid NMB when monitoring Volatile anesthetics reduce NM conduction SSEP Avoid Nitrous Oxide- may ↑ PVR & exacerbate pulmonary HTN. TIVA opioid / propofol combo with 0.33 MAC volatile anesthetic. When spinal curvature is straightened / distracted (excessive traction) may be spinal cord ischemia. “wake up test” still used by some in conjunction with MEP and SSEP monitoring. (0-20% may have recall) discussion pre op.

Complications / Management POVL Optic neuropathy, retinal artery occlusion, cerebral ischemia Associated with instrumentation, prolonged intra-op hypotension, anemia, large blood loss and prolonged surgery. VAE Stems from large amounts of exposed open bone and elevated surgical incision relative to heart. Capnography, mass spectrometry and precordial Doppler useful in detection. (↑ ET N2 & ↓ ETCO2) Tx. with saline poured onto field, level bed, L lateral position, DC any N20, aspirate air with central line, flip supine and institute CPR.

Summary See attached handout

References Barash, P., Cullen, B., Stoelting,R., Cahalan, M., & Stock, M. (2009). Clinical Anesthesia. (6th Edition). Philadelphia: Lippincott Williams & Wilkins. Hines, R., and Marschall, K. (2008). Stoelting’s anesthesia and co-existing disease. (5th Edition). Philadelphia: Churchill Livingston. Urman, R., & Ehrenfeld, J. (2009). Pocket anesthesia. Philadelphia: Lippincott Williams & Wilkins.