Definition of Lumbar Scoliosis
Scoliosis of the lumbar spine is a lateral curvature of the lumbar vertebral column with a Cobb angle of 10 degrees or more, typically accompanied by vertebral rotation. 1, 2
Core Diagnostic Criteria
- A Cobb angle measurement of at least 10 degrees in the coronal plane is required to diagnose scoliosis, distinguishing it from normal spinal asymmetry 1, 2, 3
- The deformity involves both lateral curvature and rotational components of the vertebrae, not just simple side-bending 2, 4
- Lumbar scoliosis specifically affects the lower spine region, though curves may extend into the thoracolumbar junction 1
Classification of Lumbar Scoliosis in Adults
When lumbar scoliosis occurs in skeletally mature patients, it falls into distinct categories that guide management 1:
- Primary degenerative (de novo) scoliosis: Develops from asymmetric disc and facet joint arthritis, predominantly causing back pain and often accompanied by spinal stenosis 1
- Progressive idiopathic scoliosis: Adolescent-onset curves that continue progressing into adulthood, usually combined with secondary degeneration 1
- Secondary curves: Result from pelvic obliquity (leg length discrepancy, hip pathology), metabolic bone disease (osteoporosis with asymmetric arthritis), or adjacent segment degeneration after prior fusion 1
Key Measurement Parameters
- Cobb angle: The primary measurement quantifying curve severity, measured between the most tilted vertebrae at the curve's upper and lower ends 2
- Vertebral rotation: Assessed using the Nash-Moe method to evaluate the rotational component 2
- Curve apex: The most laterally deviated vertebra within the curve 2
- End vertebrae: The most tilted vertebrae at the superior and inferior limits of the curve 2
Clinical Presentation Differences
- Adolescent idiopathic lumbar scoliosis typically presents with cosmetic concerns initially 5
- Adult lumbar scoliosis predominantly presents with back pain, followed by leg pain and claudication symptoms, rarely with neurological deficits, and almost never with cosmetic concerns 1
- Asymmetric degeneration creates a self-perpetuating cycle where increased asymmetric loading accelerates further degeneration and curve progression 1
Imaging Requirements
- Standing posteroanterior and lateral radiographs of the complete spine are the primary diagnostic modality 2, 4
- MRI of the complete spine is mandatory before surgical intervention to rule out neural axis abnormalities, which occur in 2-4% of adolescent idiopathic scoliosis cases 6, 7
- For congenital lumbar scoliosis, both radiographs and MRI are complementary and necessary due to 21-43% prevalence of intraspinal anomalies 8
Progression Risk Factors
- Curves exceeding 50 degrees in skeletally mature patients continue progressing at approximately 1 degree per year even after skeletal maturity 6, 8
- Skeletally immature patients with curves greater than 20 degrees have progression likelihood exceeding 70% 6, 8
- Osteoporosis significantly accelerates curve progression, particularly in post-menopausal females 1