Overview of Scoliosis in Children and Adults
Definition and Classification
Scoliosis is defined as a lateral spinal curvature of at least 10° with vertebral rotation on posterior-anterior radiograph, often accompanied by reduced thoracic kyphosis 1, 2. The condition affects approximately 3 million new cases annually in the United States, with increasing prevalence due to global aging 1.
Major Etiological Categories
Idiopathic Scoliosis (most common type encountered in general practice):
- Represents the majority of cases in children and adolescents 3
- Diagnosis of exclusion after ruling out other causes 4
- Genetic factors play a significant role, with genes associated with susceptibility, disease progression, or both 1
Congenital Scoliosis:
- Results from vertebral malformations present at birth 3
- Requires mandatory evaluation for cardiac and renal abnormalities 3
- CT imaging preferred for visualization of bony malformations and presurgical planning 4
Neuromuscular Scoliosis:
- Consequence of muscle weakness in neuromuscular diseases 5
- In cerebral palsy, can be central (from CNS damage) or peripheral (from hip dislocation causing pelvic obliquity) 5
- Muscle stiffness from fibrotic degeneration may serve as protective factor 5
- Greater incidence in tetraplegia than diplegia 5
Adult Degenerative Scoliosis (Type 1 - Primary Degenerative):
- Develops in skeletally mature patients, typically affecting those over fifty 6, 1
- Based on asymmetric disc and/or facet joint arthritis 6
- Predominantly presents with back pain, often accompanied by spinal stenosis (central or lateral) 6
- Classified as "de novo" scoliosis 6
Progressive Adolescent Idiopathic Scoliosis in Adults (Type 2):
- Thoracic and/or lumbar curves that progress into adult life 6
- Usually combined with secondary degeneration and/or imbalance 6
- May occur in patients with or without prior surgical treatment 6
Secondary Adult Curves (Type 3):
- Type 3a: Due to oblique pelvis from leg length discrepancy, hip pathology, or as secondary curve in other scoliosis types 6
- Type 3b: Related to metabolic bone disease (mostly osteoporosis) combined with asymmetric arthritic disease and/or vertebral fractures 6
Pathophysiology
Pediatric Idiopathic Scoliosis
The pathogenesis is multifaceted and includes 1:
- Evolutionary adaptations to bipedalism
- Developmental spinal aberrations
- Homeostatic spinal aberrations
- Complex genetic factors affecting multiple biological processes 1
Adult Degenerative Scoliosis Pathomechanism
Asymmetric degeneration creates a predictable cascade 6:
- Asymmetric load or degeneration occurs in lumbar or thoracolumbar spine
- Increased asymmetric load accelerates degeneration and deformity progression
- Destruction of facet joints, joint capsules, discs, and ligaments develops
- Mono- or multisegmental instability emerges
- Spinal stenosis ultimately develops 6
Osteoporosis significantly accelerates curve progression, particularly in post-menopausal females 6.
Pathogenic mechanisms include 1:
- Angiogenesis and inflammation
- Extracellular matrix degradation
- Neural associations
- Hormonal influences
Clinical Presentation
Pediatric Patients
- Often asymptomatic or detected during screening 3
- Cosmetic concerns in some cases 3
- Rarely present with neurological deficits 6
Adult Patients
Present predominantly with back pain first, then leg pain and claudication symptoms 6:
- Rarely present with neurological deficit 6
- Almost never present with cosmetic concerns 6
- Pain may be functionally disruptive 4
Diagnostic Evaluation
Physical Examination
The Adams forward bend test combined with scoliometer measurement provides the most reliable clinical assessment 4:
- Adams Forward Bend Test: sensitivity 84.37%, specificity 93.44% 4
- Scoliometer Measurement: sensitivity 90.62%, specificity 79.76% 4
Standing posture assessment should evaluate 4:
- Shoulder height asymmetry (key indicator) 4
- Pelvic obliquity
- Trunk balance
Neurological examination must assess 4:
- Focal neurological deficits
- Abnormal reflexes
- Muscle weakness
- Pes cavus (high-arched feet) 4
Skin examination should check for cutaneous stigmata suggesting spinal dysraphism 4:
- Hemangiomas
- Hairy patches
- Dermal appendages
- Sinus tracts 4
Red Flags Requiring Urgent Evaluation
The following atypical features mandate immediate specialist referral 4:
- Left thoracic curve (atypical pattern)
- Short segment curve
- Absence of apical segment lordosis/kyphosis
- Long thoracolumbar curve
- Rapid curve progression (>1° per month)
- Functionally disruptive pain
- Focal neurological findings
- Male sex 4
Radiographic Assessment
PA and lateral spine radiographs are essential for 7, 4:
- Definitive diagnosis and classification 4
- Determining exact curve magnitude using Cobb angle measurement 2
- Assessing vertebral anomalies 4
- Evaluating curve progression over time 4
- Measuring vertebral rotation using Nash-Moe method 2
Clinical examination alone cannot determine these critical parameters 4.
Cobb Angle Measurement Technique 2:
- Identify apex, end vertebra, neutral vertebra, and stable vertebra
- Measure angle between lines drawn parallel to superior endplate of upper end vertebra and inferior endplate of lower end vertebra
- Classify curve type as primary or secondary, structural or nonstructural 2
Skeletal Maturity Assessment (Risser Staging) 8:
- Critical for determining progression risk and monitoring frequency
- Risser stages 0-3: higher risk, requires more frequent monitoring 8
- Risser stages 4-5: lower risk, less frequent monitoring needed 8
Advanced Imaging
MRI evaluation should be obtained before surgery to rule out neural axis abnormalities, particularly in patients with 8, 4:
- Left thoracic curve
- Short segment curve
- Absence of apical segment lordosis
- Rapid curve progression
- Pain
- Neurological findings 8
CT imaging is preferred for 4:
- Visualization of bony malformations
- Presurgical planning 4
Invasive Diagnostic Procedures for Adult Scoliosis
When conservative management fails, consider 6:
- Discograms
- Facet blocks
- Epidural and root blocks
- Immobilization tests 6
These procedures correlate with clinical and pathomorphological findings and guide least invasive, most rational treatment 6.
Risk Factors for Progression
Pediatric Population
Skeletally immature patients have higher risk of progression and require more vigilant monitoring 7:
- In skeletally immature individuals with curves >20°, likelihood of progression may exceed 70% 8
- Progression most likely during periods of rapid growth 2
- Optimal follow-up interval may be as short as 4 months during rapid growth phases 2
Female patients have significantly higher risk 7:
- Female-to-male ratio of 10:1 for larger curves 7
Curve location matters 8:
- Thoracic curves >50° in skeletally mature patients may continue to progress at approximately 1° per year even after skeletal maturity 8
Adult Population
Progression factors include 6:
- Osteoporosis (particularly post-menopausal females)
- Asymmetric arthritic disease
- Vertebral fractures
- Pre-existing curves >30° at skeletal maturity 2
Treatment Algorithm
Curves <15°
Regular observation with radiographic monitoring every 12-18 months for stable curves 7:
- Annual clinical evaluation using Adam's forward bend test 7
- Refer to orthopedics if concern about progression 7
Curves 15-20°
More frequent monitoring every 6 months to detect potential progression 7:
- Physical therapy focusing on core strengthening and postural awareness can help manage symptoms 7
- Continue clinical surveillance 7
Curves 20-50°
Treatment based on skeletal maturity and progression risk 3:
- Orthotic management (bracing) for skeletally immature patients with progressive curves 3
- Continued monitoring for skeletally mature patients 3
- Consider surgical consultation if documented progression despite skeletal maturity 8
Curves >50°
Surgical intervention is typically recommended when Cobb angle exceeds 50° in skeletally mature patients due to risk of continued progression into adulthood 8:
- Curves >50° may progress at approximately 1° per year even after skeletal maturity 8
- Surgical correction with fusion is standard approach 3
Additional surgical indications include 8:
- Documented curve progression despite skeletal maturity
- Significant pain not responding to conservative measures
- Significant cosmetic concerns affecting quality of life 8
Surgical Planning Considerations
Curve flexibility assessment influences surgical planning 8:
- Evaluated using side bending radiographs
- Push prone radiographs
- Fulcrum bending radiographs
- Traction radiographs 8
Both allograft and autograft are medically necessary components of fusion procedure 8:
- Cadaveric allograft and demineralized bone matrix considered medically necessary regardless of implant shape 8
- Combined use optimizes fusion potential while minimizing donor site morbidity 8
Adult Degenerative Scoliosis Treatment
Treatment tailored to specific symptomatology 6:
- Decompression for stenosis
- Correction of deformity
- Stabilization and fusion
- Combination procedures as needed 6
Specific surgical challenges in adults include 6:
- Age and general medical condition
- Length of fusion required
- Condition of adjacent segments
- Lumbosacral junction integrity
- Osteoporosis management
- Previous scoliosis surgery complications
- Chronified back pain and muscle imbalance 6
Minimal invasive procedures may be appropriate for elderly patients 6:
- Address most relevant clinical problem
- May ignore overall deformity when appropriate 6
Monitoring Protocols
Radiation Safety
Avoid excessive radiation exposure by following recommended monitoring intervals 7:
- Limit spine radiographs to once every 12 months for adolescents at Risser stages 0-3 8
- Every 18 months for Risser stages 4-5 8
- Serial monitoring necessary for skeletally immature patients, no more than once every 6 months 4
After Skeletal Maturity
Only curves >30° require monitoring for progression after skeletal maturity is attained 2.
Referral Criteria
Refer to specialist if 3:
- Curve >10° in patient younger than 10 years of age
- Curve >20° in patient 10 years of age or older
- Atypical features present
- Associated back pain
- Neurological abnormalities 3
Common Pitfalls to Avoid
Assuming no progression due to absence of symptoms - curves can progress silently 7:
- Regular radiographic monitoring essential even in asymptomatic patients 7
Delaying evaluation of new or worsening symptoms leads to poor outcomes 7.
Overtreatment of mild curves 7:
- Surgical intervention not indicated for mild scoliosis 7
- Surgery typically only considered for curves >50° in young adults 7
Overlooking potential neural axis abnormalities 8:
- Must evaluate with MRI before surgical intervention in at-risk patients 8
Failing to evaluate for associated abnormalities in congenital scoliosis 3:
- Mandatory cardiac and renal evaluation required 3
Ignoring differential diagnosis 4:
- Must distinguish idiopathic from syndrome-related (Marfan, Ehlers-Danlos) and secondary causes (tumors like osteoid osteoma) 4
Special Populations
Spina Bifida
Two distinct types of scoliosis occur 5:
- Lesional scoliosis: malformative (directly from vertebrae in myelomeningocele), secondary (from unilateral hip dislocation or muscular imbalance), or acquired (from muscle weakness)
- Supralesional scoliosis: from neurological structure impairment (especially ponto-cerebellar carrefour) or acquired tethered cord, can affect any spinal segment including above primitive lesion level 5
Neuromuscular Diseases
Main curve remains reducible for longer periods 5:
- Less reducible secondary cervical curve can limit correction possibilities due to need for head alignment 5