Adult Scoliosis
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Direct answer
Adult scoliosis — a Cobb angle above 10 degrees in a skeletally mature patient — arrives as two different diseases: the untreated adolescent idiopathic curve that keeps creeping, and the de novo degenerative scoliosis of the elderly lumbar spine, where asymmetric disc and facet wear tilts the column. Progression rules anchor the follow-up: curves beyond 50 degrees advance about one degree a year, while degenerative lumbar curves can progress faster once rotatory subluxation begins. Treatment is driven far less by the angle than by symptoms and balance — pain, radiculopathy, claudication and sagittal malalignment decide who gets decompression alone, who gets fusion, and who is observed.
What you must remember
- Two populations: progression of an adolescent idiopathic curve (thoracic, balanced) versus de novo degenerative lumbar scoliosis (short curve, listhesis, stenosis, older patient).
- Progression rules (quoteable): AIS curves over 50 degrees progress roughly 1 degree per year; curves of 30-50 degrees creep slowly; degenerative lumbar curves may progress faster, especially with rotatory listhesis and asymmetric disc collapse.
- Symptom triad: axial back pain; radiculopathy and claudication from stenosis — typically concave-side nerve root compression and central canal narrowing; and coronal plus sagittal imbalance.
- Workup: standing full-spine anteroposterior and lateral radiographs (Cobb, coronal and sagittal balance, rotatory subluxation), MRI for stenosis, DEXA before long fusions in the elderly — osteoporotic bone is the real constraint; pelvic incidence minus lumbar lordosis (PI-LL) mismatch above about 10 degrees correlates with pain and disability, the Roussouly-era measure turned exam staple.
- Treatment spectrum: observation and physiotherapy; injections; decompression alone for isolated stenosis with a small, flexible curve and no listhesis; decompression with limited fusion; long instrumented correction with realignment for imbalance.
- Surgery drivers: imbalance (coronal or sagittal), neurological deficit, curve progression — not the Cobb number alone; adult idiopathic surgery is generally considered for curves beyond about 50 degrees with pain or progression.
- Complication reality: pseudoarthrosis, proximal junctional kyphosis, infection and neurological risk all run higher than in adolescent surgery, and elderly bone quality decides construct strategy; bracing does not work in adults — a standard contrast with adolescent management.
- Indian context: advanced untreated curves still present in parts of the country, while degenerative scoliosis grows fastest as life expectancy rises; long fusions in osteoporotic bone with limited access to cement-augmented screws are the practical challenge.
Decompression alone or fusion?
A 63-year-old with neurogenic claudication has an L3-5 stenosis under a 22-degree flexible curve with no rotatory listhesis and a balanced sagittal profile: decompression alone is defensible, because removing bone does not destabilise a spine that is already stable, and fusing an elderly spine adds a year of healing risk for nothing. Contrast a 58-year-old with a 35-degree curve, lateral listhesis at L3-4, back pain dominating her claudication and a PI-LL mismatch of 15 degrees: decompression here opens a collapsing segment, and the operation becomes decompression with fusion of the pathological segments — restoring disc height, correcting the slip and rebuilding lordosis. The decision variables the examiner is listening for are listhesis, curve flexibility, sagittal balance and which symptom dominates; the Cobb angle is a bystander in this conversation, which is precisely the lesson of adult deformity surgery.
Balance over magnitude
Adolescent practice trains you to watch numbers, and adult practice punishes it. A balanced 45-degree thoracic curve in a comfortable 40-year-old may need nothing; a 30-degree lumbar curve with 4 cm of sagittal vertical axis and a PI-LL mismatch can be disabling and operative. The exam frames it as "why operate on the smaller curve?" and the answer is alignment and symptoms, not degrees. The second trap is importing adolescent tools: a brace does nothing for an adult curve, and curve magnitude is not the operative threshold it is in growing spines — progression risk, stenosis and imbalance are.
Frequently asked questions
How fast do untreated adolescent idiopathic curves progress in adulthood?
Curves beyond 50 degrees progress about one degree per year, while moderate curves of 30-50 degrees progress only slowly after maturity.
What is de novo degenerative scoliosis?
A new lumbar curve in an older adult from asymmetric disc and facet degeneration, typically short, with rotatory listhesis and stenosis.
What does a PI-LL mismatch above 10 degrees indicate?
Sagittal malalignment — lumbar lordosis insufficient for the pelvic incidence — which correlates with pain and disability and drives realignment surgery.
When is decompression alone acceptable in adult scoliosis?
Isolated stenosis with a small, flexible curve, no rotatory listhesis and no significant instability or imbalance.
Does bracing help adult scoliosis?
No — bracing works by guiding a growing spine; in the mature spine it neither corrects nor reliably relieves symptoms, unlike in adolescents.