When discussing scoliosis, the Cobb angle often takes center stage as the primary metric for assessing the severity of spinal curvature. However, in adults, the Cobb angle is just one piece of the puzzle and not always the most critical factor when evaluating the condition or planning treatment. Below, we explore why other considerations often outweigh the Cobb angle in adult scoliosis management.
Why Cobb Angle Alone is Insufficient (1)
The Cobb angle measures the degree of spinal curvature on an X-ray. While it provides a useful quantitative assessment, it has limitations, particularly in adult patients:
- Doesn’t Reflect Symptoms: The Cobb angle does not directly correlate with the severity of symptoms such as pain, stiffness, or reduced mobility, which are often the primary concerns for adults.
- Neglects Functional Impact: Functional limitations, including difficulties with walking, standing, or performing daily activities, are not captured by the Cobb angle.
- Overlooks Degenerative Changes: In adults, scoliosis is frequently accompanied by degenerative disc disease, spinal stenosis, or facet joint arthritis, which the Cobb angle does not address.
- Ignores Postural Balance: Adult scoliosis often affects overall posture and balance, particularly in the sagittal plane (front-to-back alignment), which the Cobb angle does not measure.
Key Considerations in Adult Scoliosis
When managing adult scoliosis, clinicians must adopt a more holistic approach that goes beyond the Cobb angle (2). Important factors include:
1. Pain and Quality of Life (2)
- Pain, often localised in the lower back, is a common driver for seeking treatment.
- Quality of life assessments, including sleep disturbances, social interactions, and mental health, play a significant role in treatment planning.
Adults with scoliosis will often experience changes in their quality of life due to the pain or weaknesses associated with the condition.
2. Sagittal Balance (3)
- The alignment of the spine in the sagittal plane is critical for maintaining an efficient, pain-free posture. Anterior sagittal balance is most associated with reductions in quality of life compared to posterior sagittal balance.
- Imbalances in the sagittal plane, such as a forward-leaning posture, can lead to significant discomfort and increased falls risk.
3. Neurological Symptoms (4)
- Compression of nerves due to spinal deformity or stenosis can result in leg pain, numbness, or weakness, which often demands urgent attention.
- Realignment of the spine and improvement of posture can help improve neurological symptoms.
Radiation of symptoms from the back can occur in some patients with scoliosis. This means that they may experience pain, pins and needles or numbness into the buttocks or legs.
4. Progression Risk (5)
- For adults, the risk of curve progression is generally lower than in adolescents, but certain factors, such as osteoporosis or pre-existing degeneration, can accelerate changes.
- Adults with degenerative scoliosis may progress on average approximately 3 degrees per year.
- Adults that are living with scoliosis during adulthood have more changes of their curve progressing if the curve was more than 30 degrees when they entered into adulthood.
Adults living with scoliosis are at risk of curve progression but also at risk of symptoms, such as pain, risk of falls and loss of function, without appropriate treatment.
5. Physical Function
- Difficulty with walking, climbing stairs, or other functional impairments may guide treatment priorities more than the curvature measurement itself.
- Prevention of falls in these patients will help maintain function.
Evidence-Based Management Approaches
Research underscores the importance of individualised treatment strategies for adult scoliosis, focusing on symptom relief and functional improvement:
- Non-Surgical Interventions (6)
- Scoliosis specific exercises are ideal for these patients. General physical therapy and chiropractic treatment are sometimes appropriate adjuncts to treatment but they do not address the scoliosis specifically.
- ‘Core strengthening’ is not a specifically targeted approach to scoliosis.
- Customised Bracing for prevention of curve progression and maintenance of stability is important in these patients. General ‘off the shelf’ braces do not address the scoliosis specifically for each patient.
- Pain management, including medications or epidural steroid injections.
- Surgical Options (2)
- Reserved for severe cases where pain, neurological symptoms, or functional limitations are not manageable through conservative means.
- Decision-making incorporates factors such as age, bone quality, and overall health, not just the Cobb angle.
Conclusion
While the Cobb angle is an important diagnostic tool, it is not the definitive measure of severity or the most critical consideration in adult scoliosis management. A comprehensive approach that evaluates pain, function, neurological health, and overall alignment is essential for effective treatment planning.
References
- Schwab, F. J., Blondel, B., Bess, S., Hostin, R., Shaffrey, C. I., Smith, J. S., Boachie-Adjei, O., Burton, D. C., Akbarnia, B. A., Mundis, G. M., Ames, C. P., Kebaish, K., Hart, R. A., Farcy, J. P., & Lafage, V. (2013). Radiographical spinopelvic parameters and disability in the setting of adult spinal deformity: a prospective multicenter analysis. Spine (Phila Pa 1976), 38(13), E803-812. https://doi.org/10.1097/BRS.0b013e318292b7b9
- Aebi, M. (2005). The adult scoliosis. Eur Spine J, 14(10), 925-948. https://doi.org/10.1007/s00586-005-1053-9
- Glassman, S. D., Bridwell, K., Dimar, J. R., Horton, W., Berven, S., & Schwab, F. (2005). The impact of positive sagittal balance in adult spinal deformity. Spine (Phila Pa 1976), 30(18), 2024-2029. https://doi.org/10.1097/01.brs.0000179086.30449.96
- Smith, J. S., Fu, K. M., Urban, P., & Shaffrey, C. I. (2008). Neurological symptoms and deficits in adults with scoliosis who present to a surgical clinic: incidence and association with the choice of operative versus nonoperative management. J Neurosurg Spine, 9(4), 326-331. https://doi.org/10.3171/spi.2008.9.10.326
- Ascani, E., Bartolozzi, P., Logroscino, C. A., Marchetti, P. G., Ponte, A., Savini, R., Travaglini, F., Binazzi, R., & Di Silvestre, M. (1986). Natural history of untreated idiopathic scoliosis after skeletal maturity. Spine (Phila Pa 1976), 11(8), 784-789. https://doi.org/10.1097/00007632-198610000-00007
- Palazzo, C., Montigny, J. P., Barbot, F., Bussel, B., Vaugier, I., Fort, D., Courtois, I., & Marty-Poumarat, C. (2017). Effects of Bracing in Adult With Scoliosis: A Retrospective Study. Arch Phys Med Rehabil, 98(1), 187-190. https://doi.org/10.1016/j.apmr.2016.05.019
