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Scoliosis Surgery: Complications Tamara Simon, M.D. July 2004 Scoliosis: Definition • Scoliosis: lateral displacement or curvature of the spine, usually occurs with• Kyphosis: spinal deformity with anteroposterior angulation (can occur in isolation , from destruction or injury to the vertebral bodies) • Severity of these two conditions is defined by measurement of the Cobb angle of curvature that is formed by the limbs of the convex primary curvature Cobb Angle Causes of Kyphoscoliosis • Idiopathic (80%) • Neuromuscular disease – Muscular dystrophy – Polio – Cerebral palsy • Vertebral disease – – – – Osteoporosis/ osteomalacia Pott’s disease Neurofibromatosis Rickets • Disorders of connective tissue – Marfan’s syndrome – Ehlers-Danlos syndrome – Morquio’s syndrome • Acquired abnormalities – Thoracoplasty – Fibrothorax Diagnosis/ Prognosis • Diagnosis is made by physical examination • Extent is often underestimated until radiographs are visualized • Degree of spinal deformity is the most important risk factor for respiratory failure, and the effects of kyphosis and scoliosis are additive Pathophysiology • PFTs demonstrate a restrictive pattern usually, with decreased TLC, VC, FRC, and compliance (effects of breathing at low lung volumes) • ABG demonstrates hypoxemia without hypercapnia is seen in moderate to severe disease; V/Q mismatch has been reported with a scoliosis angle greater than 65 degrees • Pulmonary hypertension can develops as a result of persistent hypoxemia • Nocturnal hypoventilation and arterial oxygen desaturation are described during REM. • Exercise limitation is often present in patients with kyphoscoliosis. However, there is a normal breathing pattern response to exercise and a normal maximum tidal volume to vital capacity ratio. Hence, exercise intolerance may be a result of physical deconditioning Treatment • Mild disease has a good prognosis and requires supportive care only • In adults, surgery is of questionable benefit and carries a significant complication rate • In adolescents, both surgery and brace treatment improve lung function. • Medical therapy can include pulmonary rehabilitation, supplemental oxygen as needed, and managing ventilatory failure (i.e. negative pressure ventilators, positive pressure ventilation administered via tracheostomy, and more recently, noninvasive positive pressure ventilation. …or Surgery A Standing PA XR of 6-year-old with neurofibromatosis, curve 38 degrees B Standing PA XR. Despite bracing, her curve increased to 67 degrees C Patient has unresectable neurofibroma occluding one lung, but needs continued chest cavity growth and lung expansion. D Standing PA XR after dual growth rods inserted, routine rod lengthening 6 months later. Curve is now 45 degrees. Surgery: Early Complications in PICU • Coagulopathy • Ileus (3.5% to 6.1%) – Usually seen for 36-48 hours • Fat embolism – Tachycardia, tachypnea, altered mental status, pyrexia – Release of fat into bloodstream after long-bone procedures • Pneumothorax • Chylothorax • Hemothorax Surgery: Early Complications (cont) • SIADH (33% of children) – Hyponatremia, hypoosmolality concentrated urine, normal renal and adrenal function – Excessive action of ADH in renal tubules; release of ANP – Thought due to increased manipulation of dura and neural tracts as well as blood loss • Pancreatitis (14% of all patients) – Persistent vomiting, abdominal pain, elevation of serum amylase and lipase – Inflammation of pancreatic tissue – Thought related to positioning, ischemia, hypotension, etc. Surgery: Late Complications • Cholelithiasis – Immediately post-op secondary to hemolysis coupled with postoperative fasting – Gallstones may persist for several years (11.1% by ultrasound)- but not specific to scoliosis patients – 50% are asymptomatic, less than 25% will require intervention – Present with acute cholecystitis (RUQ pain, guarding, rebound tenderness, leukocytosis, and pyrexia) Surgery: Late Complications • Superior mesenteric artery syndrome – Nausea, intermittent bilious vomiting, abdominal pain, distention – Due to extrinsic compression of third portion of duodenum between SMA and aorta – Associated with burns, anorexia, weight loss, tumors, and spinal manipulation (usually patients are 20% underweight) – Reasons for association may include adolescent growth spurt; upward tension on SMA root and mesentery,decreasing SMA angle and compressing duodenum; and relative spinal extension in scoliosis creating more vertical tension on soft tissue anterior to spine Surgery: Late Complications A characteristic UGI series showing sharp cutoff of contrast material at the third portion of the duodenum (secondary to compression by the superior mesentery artery) References • Barron RM, Schwarzstein RM. Diseases of the Chest Wall, Up to Date • Canale: Campbell's Operative Orthopaedics, 10th ed., MD Consult • Feldman: Sleisenger & Fordtran's Gastrointestinal and Liver Disease, 7th ed., MD Consult • Shapiro G, Green DW, Fatica NS, et al. Medical complications in scoliosis surgery. Current Opinion in Pediatrics, 2001, 13:36-41.