What is the diagnosis, workup, and treatment for a patient with a lateral spinal curvature (scoliosis)?

Lateral Spinal Curvature (Scoliosis): Diagnosis, Workup, and Treatment

Scoliosis is a lateral spinal curvature ≥10° with vertebral rotation, diagnosed primarily with upright PA and lateral spine radiographs, and managed based on curve magnitude, skeletal maturity, and etiology—with observation for curves <20°, bracing consideration for 20-40° in immature patients, and surgery typically indicated when curves exceed 50° in skeletally mature patients. 1, 2, 3

Diagnosis and Classification

Definition and Types

• Scoliosis is defined as lateral spinal curvature with a Cobb angle ≥10° measured on upright radiographs 3, 4
• Four major etiologic categories exist: idiopathic (75-80% of cases), congenital, neuromuscular, and degenerative 3
• Adolescent idiopathic scoliosis (ages 10-18 years) represents the vast majority of cases encountered in practice 3
• Female predominance is marked, with a 10:1 female-to-male ratio for curves exceeding 40° 3

Initial Imaging Protocol

• Obtain upright PA (posteroanterior) and lateral spine radiographs of the complete spine as the primary diagnostic modality 2, 3
• PA views are preferred over AP to reduce breast radiation exposure 3
• Radiographs must visualize cervical, thoracic, and lumbar spine to assess complete spinal alignment 3

Critical Red Flags Requiring MRI Evaluation

Atypical Curve Patterns and Clinical Features

Before any surgical intervention, obtain MRI of the entire spine to rule out neural axis abnormalities, particularly when these risk factors are present: 1, 2

• Left thoracic curve pattern (right thoracic is typical for idiopathic scoliosis) 2, 3
• Short segment curve 2
• Absence of apical segment lordosis or presence of hyperkyphosis 2
• Rapid curve progression (>1° per month) 2
• Functionally disruptive pain 2
• Focal neurological findings 2
• Male sex with presumed idiopathic scoliosis 2
• Pes cavus deformity 2

Special Considerations for Congenital Scoliosis

• MRI of the complete spine is mandatory before any treatment decision in congenital scoliosis due to 21-43% prevalence of intraspinal anomalies 2
• Intraspinal anomalies include tethered cord, filar lipoma, syringohydromyelia, and diastematomyelia 2, 3
• Critical pitfall: Normal neurological examination does not predict normal MRI—physical exam accuracy is only 62% for detecting intraspinal anomalies 2, 3
• Isolated hemivertebra carries a 28% intraspinal anomaly rate 2
• Obtain CT spine for surgical planning if surgery is considered, as it reduces screw misplacement from 15.3% to 6.5% 2

MRI Protocol Specifications

• MRI without IV contrast is the standard protocol for detecting intraspinal abnormalities 2
• Add IV gadolinium contrast only when tumor or infection is suspected 2

Treatment Algorithm Based on Curve Magnitude and Skeletal Maturity

Observation Only (Curves <20°)

• Skeletally immature patients with curves <20° have <30% risk of progression 2
• For adolescents at Risser stages 0-3: limit spine radiographs to once every 12 months 1, 2, 3
• For Risser stages 4-5: radiographs every 18 months are sufficient 1, 2
• For congenital scoliosis: perform serial PA radiographs no more frequently than once every 6 months 2

Bracing Consideration (Curves 20-40° in Skeletally Immature Patients)

• Treatment is recommended when curves exceed 20-25° in skeletally immature patients 2
• Skeletally immature individuals with curves >20° have progression likelihood exceeding 70% 1, 2

Surgical Intervention Thresholds

Surgery is typically indicated when the Cobb angle exceeds 50° in skeletally mature patients due to risk of continued progression at approximately 1° per year even after skeletal maturity 1, 2

Additional surgical indications include:

• Curves exceeding 40-50° with remaining growth potential to prevent further progression 2
• Documented curve progression despite skeletal maturity 1, 2
• Significant pain not responding to conservative measures 1
• Significant cosmetic concerns affecting quality of life 1

Surgical Approach

• Posterior spinal fusion with instrumentation is the standard surgical approach for curves exceeding surgical thresholds 2
• Both allograft and autograft bone grafting are medically necessary to achieve solid arthrodesis and optimize fusion potential while minimizing donor site morbidity 1, 2

Pre-Operative Evaluation for Severe Scoliosis

Mandatory Assessments

• MRI of the entire spine is mandatory before any surgical intervention—neural axis abnormalities occur in >20% of patients with severe curves 1, 2
• Pulmonology evaluation to assess baseline lung function and screen for sleep hypoventilation with nocturnal oximetry or polysomnography 1
• Cardiology evaluation to assess for cardiomyopathy or arrhythmia risk under anesthesia 1
• Nutritional optimization to support healing and minimize complications 1

Post-Operative Management

• Aggressive airway clearance and respiratory support are critical postoperatively 1
• If preoperative sleep studies show hypoventilation, initiate noninvasive ventilation before surgery and plan to extubate to noninvasive ventilation postoperatively 1
• Pain management must be carefully titrated to promote airway clearance while minimizing respiratory suppression 1

High-Risk Curve Patterns

Congenital Scoliosis with Rapid Progression

• Unilateral bar with contralateral hemivertebra has extremely high progression risk of >10° per year 2, 3
• These patients require close monitoring with serial radiographs every 6 months maximum 2

Thoracic Curves in Skeletally Mature Patients

• Thoracic curves >50° may continue to progress at approximately 1° per year even after skeletal maturity 1, 2

Common Pitfalls to Avoid

• Never assume no progression due to absence of symptoms—curves can progress silently, particularly in skeletally immature patients 2
• Never overlook neural axis abnormalities—2-4% of patients diagnosed with idiopathic scoliosis actually have neural axis abnormalities causing the deformity 2, 3
• Never skip MRI in congenital scoliosis—21-43% have intraspinal anomalies that alter surgical planning 1, 2
• Never rely on clinical examination alone to determine exact curve magnitude or evaluate progression—radiography is essential 3