Epidemiology & Risk Factors

Demographics: Adolescents during pubertal growth spurt (typically 12–17 yo); slight male predominance (M > F or M = F).
Pathophysiology: Osteochondrosis of secondary ossification centers in vertebral ring apophyses → abnormal endplate development → anterior wedging of vertebral bodies.
Risk Factors: Positive family history (autosomal dominant inheritance pattern suspected with variable expressivity), repetitive mechanical stress/axial loading.

Clinical Features

History:
- Insidious onset of dull, non-radiating mid-to-lower thoracic back pain.
- Pain worsened by prolonged sitting, standing, or physical activity; relieved by rest.
- Cosmetic concerns regarding posture (“hunchback” appearance).
Physical Exam (PE):
- Rigid thoracic hyperkyphosis: Does not correct with active spinal hyperextension or prone positioning (key distinction from postural kyphosis).
- Adam forward bend test: Demonstrates a sharp, angular deformity (gibbus deformity) rather than a smooth, rounded curve.
- Compensatory deformities: Increased cervical and lumbar hyperlordosis.
- Associated findings: Tight hamstrings, tight pectoralis muscles, and contracture of anterior shoulder girdles.
- Neurologic exam: Typically normal; signs of myelopathy/cord compression are rare.

Initial / Best Initial Test: Standing full-spine lateral and AP radiographs (XR).
Confirmatory / Diagnostic Criteria (Sorensen Criteria):
- Thoracic kyphosis > 45° (measured via Cobb angle; normal is 20°–40°).
- Anterior wedging ≥ 5° across ≥ 3 consecutive, adjacent vertebral bodies.
Key Radiographic Findings:
- Schmorl nodes (herniation of nucleus pulposus through weakened vertebral endplates).
- Irregular/flattened vertebral endplates and narrowed intervertebral disc spaces.
Key Labs: Normal (ESR, CRP, CBC normal; indicated only to exclude infection or inflammatory arthropathy).
Advanced Imaging (MRI): Reserved for pts with atypical pain, neurological symptoms, or pre-op planning.

Postural Kyphosis (Postural Roundback):
- Differentiating features: Flexible curve (fully corrects with voluntary extension or prone hyperextension); smooth contour on forward bend; normal XR without anterior wedging or Schmorl nodes.
Congenital Kyphosis:
- Differentiating features: Appears in infancy/early childhood; caused by failure of formation (hemivertebra) or failure of segmentation (unsegmented bar); rapid progression; high risk of neurologic deficit.
- Ankylosing Spondylitis:
- Differentiating features: Presents in late adolescence/young adulthood with inflammatory back pain (morning stiffness > 30 min, improves with exercise); (+) HLA-B27, elevated ESR/CRP; bilateral sacroiliitis on pelvic XR/MRI.
Tuberculous Spondylitis (Pott Disease):
- Differentiating features: Constitutional signs (fever, night sweats, weight loss); systemic TB exposure; focal lytic destruction of disc and adjacent vertebrae on XR/MRI.

Mild / Asymptomatic (Curve < 60° and skeletally mature or immature):
- First-line: Observation with serial clinical and XR exams every 4–6 months until skeletal maturity.
- Physical therapy (PT) for extensor muscle strengthening, hamstring stretching, and core stability.
- PRN NSAIDs for symptom relief.
Moderate / Progressive (Curve 60°–80° in skeletally immature pts, Risser grade 0–2):
- Second-line: Bracing (e.g., Milwaukee brace or modified thoracolumbosacral orthosis [TLSO]).
- Worn 16–23 hrs/day until skeletal maturity (Risser grade 4–5 or cessation of vertical growth).
- Goal: Halts progression; does not permanently reverse structural wedging.
Severe / Refractory (Curve > 75°–80°, intractable pain, or neurologic deficits):
- Refractory / Surgical: Posterior spinal fusion with instrumentation (± anterior release).

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