Adult degenerative scoliosis (ADS) is defined as a three-dimensional abnormality of the spine, with lateral spine curvature greater than 10 ° (Cobb angle >10 °), in a skeletally mature individual.1 Cobb angle is measured by taking the terminal vertebrae of the spinal curve and extending a line from the endplates, then measuring the angle of the intersection.1 In ADS, the abnormal curve of the spine forms during adulthood due to an asymmetric degeneration of spinal motion segments.2
Although many classification systems exist, scoliosis is often classified in 5 main categories: idiopathic, neuromuscular, congenital, syndrome-related, and tumor-related.3 The most common etiology is idiopathic, with over 90% of cases categorized in this group.4 Idiopathic scoliosis is, by definition, a spinal anomaly of unknown etiology. This is a diagnosis of exclusion when evaluation reveals no anomalous or malformed vertebrae and a normal neurologic exam.
ADS specifically can be subcategorized into two major classifications: primary degenerative scoliosis and secondary degenerative scoliosis.
Primary degenerative scoliosis occurs with de novo degeneration of the intervertebral discs and/or facet joints, with asymmetric degeneration leading to incompetence of the posterior structural elements.
Secondary degenerative scoliosis encompasses a host of etiologies including scoliosis secondary to prior spinal surgeries, trauma, cancerous growth, osteoporosis, or as a consequence of an oblique pelvis, leg length discrepancy, or hip pathology. 5
Epidemiology including risk factors and primary prevention
The prevalence of ADS in the general population ranges from 1-10%. Within this population, the smaller angle curves are seen much more frequently than larger, more severe curves. As reported by Silvia and Lenke (2010) 6, the prevalence of curve magnitudes of 10 °, 10-20 °, and >20 ° are 64%, 44%, and 24%, respectively. 6 While the male to female ratio is 1:1 in curves under 10°, the ratio changes to 5.4:1 female to male ratio with curves greater than 20°.2,4 Degenerative scoliosis is often diagnosed in women between the ages of 20-40, although in some instances may be seen initially as late as 80 years of age. The risk factors for ADS are extensive, with predisposing factors including greater BMI, presence of exaggerated lumbar lordosis, low bone mineral density, presence of spinal canal stenosis, and presence of thoracic kyphosis.7 Injuries, infection, tumor growth, and any form of bony/ligament dysfunction potentially can cause spinal deformity as well.
Spinal stability is derived from bone, connective tissue, muscle, and their interaction with the nervous system.8 Dysfunction in any of these elements leads to imbalance and, ultimately, to deformity.
The degenerative process leading to scoliotic deformity often begins in the intervertebral discs with structural change to disc anatomy (decreasing disc height, decreased proteoglycan and water content of discs, and increasing enzymatic degradation). This process leads to biomechanical asymmetry in load bearing causing bone remodeling and/or instability at the intervertebral and facet joints which ultimately leads to ligamentous incompetence with decline in surrounding musculature. This process culminates in development and eventual progression of the scoliotic curve.9
Table 1. Causes of Adult Degenerative Scoliosis by Pathophysiology.
|Bony Dysfunction||Trauma, radiation, tuberculosis, infection, degenerative disease, bone tumors (more commonly metastases)|
|Elastic Tissue Dysfunction||Soft tissue contractures (e.g., due to empyema, surgical treatment, burns, radiation, resultant scarring, radiation fibrosis)|
|Neuromuscular Dysfunction||Spinal cord injury, syringomyelia|
Table derived with permission from DeLisa’s Physical Medicine and Rehabilitation: Principles and Practice, p 892-899.8
Disease progression including natural history, disease phases or stages, disease trajectory (clinical features and presentation over time)
Asymmetric degeneration leads to progressively increasing asymmetric load, thereby giving rise to progression of curvature.
Curve magnitude in ADS progresses on average 3° per year.10 A patient’s age, sex, and bone mineral density does not affect the rate of curve progression.11 However, patients having a Cobb angle >30 °, lateral listhesis >6mm, apical rotation more than Grade II, or intercrest line through L5 are correlated with higher rate of curve progression.10
Increasing curvature leads to degradation of structural elements (facet joints, intervertebral discs, ligaments, etc.) which can create single or multi-level instability.
Patients with this progression can present with axial back pain, leg pain, or even claudication, however ADS rarely gives rise to more severe neurological deficits such as muscular weakness.12
Specific secondary or associated conditions and complications
Severe scoliosis can lead to a variety of secondary complications. These can include skin breakdown (ex. skin between ribs rubbing on the pelvis), difficulty with hygiene, decreased ability to perform ADLs, aesthetic concerns, and pulmonary compromise due to restrictive lung disease.
Essentials of Assessment
Evaluation should include the following elements:
- Initial onset, location, duration, characteristics and modalities of treatment to determine if consistent with ADS
- Presence of visible deformity to suggest progression
- Changes in gait pattern to suggest clinically significant progression
- Axial pain vs radicular pain. Axial pain is likely associated with the severity of the scoliotic curve and sagittal imbalance.
- Past medical and surgical history may reveal renal, cardiac, or multisystem abnormalities that correlate to a syndrome.
- Pain or nighttime pain may be associated with an underlying pathologic condition such as spondylolisthesis, Scheuermann kyphosis, syringomyelia, tethered cord, intraspinal tumor, etc. Complaints of pain must be distinguished between mild or fatigue-related pain versus severe pathologic pain, which requires further evaluations such as MRI or bone scan.
- Rapid development of a severe curve suggests a non-idiopathic type of scoliosis.
- Weakness, sensory changes, bowel or bladder control changes and other neurologic symptoms .13
- Skin markings (café-au-lait spots, hyper- or hypopigmentation, signs of neurofibromatosis, dysraphic signs, etc.)
- Leg length discrepancy should be assessed for. When present a shoe lift should be inserted on the shorter side in order to determine whether or not the curve is correctable.
- Trunk shape, balance, symmetry of shoulder height, scapular position, waist shape, pelvic tilt, and chest cage deviation
- Adams forward-bend test assesses rib and paraspinal deviation. Performed by having the patient bend forward at the waist with the knees straight. Any asymmetry should be noted as upper thoracic, midthoracic, thoracolumbar and lumbar.
- Range of motion, joint deformity, joint laxity, etc.
- Excess laxity of the joints and/or skin may be related to a syndrome such as Ehler-Danlos or Marfan.13
- Evaluate for contractures, especially of hip or knee
- Evaluate for pain relief with leaning forward (as in spinal stenosis) vs pain relief with bracing on arms to decrease axial load (consistent with ADS)
Neurologic exam to rule out intraspinal pathology:
- Balance, motor strength in all 4 limbs, sensation, reflexes, gait, tandem walk, and abdominal reflex
Activities of daily living (ADL) and Functional Independence Measure (FIM) score can be helpful in assessing function (self-care, sitting balance, breathing, feeding, transfers, mobility, ambulation, bowel and bladder management, etc.). Cognition is not affected by scoliosis, and the presence of change in cognition suggests alternate etiologies.
Laboratory studies are unnecessary except when used to determine if patient is a suitable operative candidate.
- Obtain full length standing posteroanterior and lateral spine X-rays with Cobb angle measurement.
- Consider full length supine lateral x-rays to evaluate for spontaneous correction
- Routine MRI is not indicated as part of the diagnosis. MRI may be later indicated prior to treatment such as injections or surgery.
Supplemental assessment tools
ADS patients with severe spinal curves should have pulmonary function tests (PFT) due to the potential for restrictive lung disease. Moderate curves can benefit from baseline PFTs due to risk of pulmonary compromise with progression of disease.
Early predictions of outcomes
Some studies have shown that only approximately 15% of ADS patients are reported to be symptomatic, with most cases reporting only mild to moderate symptoms.14 However when symptomatic, the 2017 study by Passias and colleagues stated that there are few conservative treatments which succeed in halting or slowing the progression. The necessity for surgery is determined by symptomatic progression and functional decline rather than radiographic severity. Given the aging population and improvement of modern surgical approaches, the rates of ADS surgery have increased.15 It was found that patient satisfaction and clinical outcomes were rated higher with surgical intervention for symptomatic cases. 15 Poor prognostic indicators for surgery included male sex and pre-existing depression. 15
Social role and social support system
As early as 2003, a statistically significant difference in mental health of patients with scoliosis and the general population of the United States was described; patients with scoliosis were seen to score between 10-30 points lower on standardized mental component summary scales (SF-36).16 Since that time, further research has shown correlations between mental health disorders and the adult spinal deformity population. In 2018, Diebo and colleagues found that 37.5% of patients with four of more levels of spinal fusion had at least one mood disorder.17 Studies have shown that patients with idiopathic scoliosis have poorer body image, greater unhappiness, lower self-esteem, increased participation in high-risk behaviors, and greater incidence of depression.18 It is important to inquire in this regard and consult a rehabilitation psychologist, psychiatrist, or social worker to address the emotional concerns of the patient and family, if needed.
Rehabilitation Management and Treatments
Available or current treatment guidelines
Bracing may also be used in adult degenerative spinal deformity, although much less frequently than seen in the pediatric population. Standard bracing principles apply, requiring 3 points of fixation between the patient and the brace however this is complicated by the fact that the spine is composed of semi-rigid structures with 6 ° of freedom between each level. Table 3 outlines general bracing guidelines for various etiologies. There have been several single-group cohort studies which demonstrate correlation between bracing and slowing of curve progression.19
Table 2. Role of Orthotic Management in Spinal Deformity of Different Etiologies
|Etiology||Roles of Orthotic Management||Type of Orthosis|
|Idiopathic||Ambulatory patients – to slow progression||Rigid|
|Myopathic/lower motor neuron||Seated patients – to provide comfort and support||Soft (must evaluate for possible orthosis-related decrease in pulmonary function)|
|Upper motor neuron||To slow progression in seated patients (likely to restrict function in standing patients)||Rigid|
|Ligamentous dysfunction||Insufficient literature; might be able to control curve but effect would be limited by deformation of intervening structures. Consider limiting use to support and comfort.||Soft|
|Degenerative||For comfort and support, will not likely affect curve||Rigid or semi-rigid|
Reprinted with permission from DeLisa’s Physical Medicine and Rehabilitation: Principles and Practice,p 901,table 34.5.8
The two basic types of rigid braces are the Milwaukee type CTLSO and a variety of TLSO braces (Wilmington, Boston, Charleston, Providence, SpineCor brace, etc.). Meta-analysis studies show that the Milwaukee brace is the most effective brace; however, it is the most cumbersome, bulky, and uncomfortable, which may be a significant consideration.8
Injections, specifically epidural steroid injections, can be used as therapeutic non-surgical intervention for symptomatic ADS, however the specific evidence is scarce. The randomized control trial by Nam and Park in 2011 provided evidence for greater effectiveness of epidural steroid injections over local anesthetic alone in reducing radicular pain and disability in patients with ADS.
Goals for surgical treatment are improved spinal alignment/balance and prevention of subsequent curve progression. Surgical indications are based on curve magnitude, clinical deformity, risk for progression, and curve pattern. Surgical treatment is generally reserved for curves greater than 50 ° for skeletally mature individuals and is tailored for each case. Surgical intervention may include spinal fusion, discectomy, decompression, or a combination thereof. Other considerations apply in various conditions.
Translation into practice: practice “pearls”/performance improvement in practice (PIPs)/changes in clinical practice behaviors and skills
Although bracing is commonly seen in the treatment of pediatric idiopathic scoliosis, because the adult skeleton is mature, this is a less common intervention in the adult population. In circumstances where curve progression is more rapid than normal rates, bracing may be considered in the ADS population to slow progression.
The evidence for epidural steroid injections in patients with ADS is scarce. However, there is some evidence of increased efficacy of epidural steroid injections over local anesthetic to reduce radicular pain and disability in patients with ADS.
There are studies which demonstrate that there is no statistically significant difference between short and long fusions in terms of coronal Cobb angle and lumbar lordosis.20 This suggests that when clinically indicated, shorter fusion lengths should be used to reduce time, costs, and risk of complication involved with surgery.
Poorer surgical outcomes in ADS have been shown to correlate with pre-existing depression and male sex.15
Cutting Edge/Emerging and Unique Concepts and Practice
While the mainstay of non-surgical treatment with bracing has stayed relatively constant, other non-surgical treatments for symptomatic relief continue to be explored. Studies have recently been posited discussing the use of spinal manipulation of patients with ADS which showed weekly spinal manipulation can improve pain and sagittal imbalance, however it has no effect on Cobb angle or vertebral rotation.21
The advancements of surgical techniques in the 21st century has led to a decrease in the amount of anterior spinal surgeries, with anterior/posterior and minimally invasive surgery (MIS) techniques increasing.22 MIS in ASD often involves an anterior retroperitoneal approach with percutaneous posterior instrumentation. The advantages of MIS include minimal blood loss, avoidance of paravertebral muscle dissection, and shorter operative times.23 MIS procedures are indicated in mild to moderate cases of ADS, and when done early in degenerative course can prevent progression of scoliosis.23 MIS is limited in severe ADS such that if the deformity cannot be reduced or contain interbody fusions they should be addressed with posterior open surgery.
Advancements in MIS for ASD includes robotic assisted pedicle screw placement, which was found to be safe, effective, more accurate and with less blood loss than free hand placement.24 Studies also have found that the use of pre-operative halo gravity traction (HGT) in patients with severe cases of adult scoliosis can improve PFTs, reduce Cobb angle, and increase weight gain thus optimizing health prior to surgeries.25 These and other techniques continue to be explored to improve treatments and outcomes for patients with ADS.
Gaps in the Evidence-Based Knowledge
There are several small cohort studies describing the correlation between bracing and slowing of curve progression in patients with ADS. However, high quality randomized control studies investigating bracing are remain limited.25
The use of therapeutic exercise intended to result in curve correction is uncertain and poorly studied. These methods are used more in Europe despite a weak evidence base. While there are many purported conservative treatments for ADS, there is significant lack of high-quality research surrounding these methods. Despite its limited effect on curve correction, therapeutic exercise remains a mainstay of treatment in the ADS population with respect to pain control and relief.
- Langensiepen S, Semler O, Sobottke R et al. Measuring Procedures to Determine the Cobb Angle in Idiopathic Scoliosis: A Systematic Review. Eur Spine J. 2013;22(11):2360-71. doi:10.1007/s00586-013-2693-9
- Grubb SA, Lipscomb HJ, & Coonrad RW: Degenerative adult onset scoliosis. Spine 13:241–245, 1988
- Dormans JP. Scoliosis (idiopathic).In: Schwartz MW, ed.5-MinutePediatric Consult.4th ed.Philadelphia, PA: Lippincott Williams & Wilkins; 2005:756-757.
- Aebi M. The adult scoliosis. Eur Spine J. 2005;14(10):925-948. doi:10.1007/s00586-005-1053-9
- Silva, F. E., & Lenke, L. G. (2010). Adult degenerative scoliosis: evaluation and management, Neurosurgical Focus FOC, 28(3), E1.
- Wang C, Chang H, Gao X, Xu J, Meng X. Risk factors of degenerative lumbar scoliosis in patients with lumbar spinal canal stenosis. Medicine (Baltimore). 2019;98(38):e17177. doi:10.1097/MD.0000000000017177
- Paul SM. Scoliosis and other spinal deformities. In: Frontera WR,DeLisa JA, Gans BM, eds.DeLisa’sPhysical Medicineand Rehabilitation: Principles and Practice.5th ed. Wolters Kluwer/Lippincott Williams & Wilkins; 2010:Chapter 34, 883-906.
- Aebi M, Gunzburg R, Szpalski M. The aging spine. Berlin and New York, NY: Springer, 2005
- Pritchett JW, & Bortel DT: Degenerative symptomatic lumbar scoliosis. Spine 18:700–703, 1993
- Korovessis P, , Piperos G, , Sidiropoulos P, & Dimas A: Adult idiopathic lumbar scoliosis. A formula for prediction of progression and review of the literature. Spine 19:1926–1932, 1994
- Aebi M. The adult scoliosis. Eur Spine J. 2005;14(10):925-948. doi:10.1007/s00586-005-1053-9
- Newton PO, Wenger DR. Idiopathic scoliosis.In: Morrissy RT,Weinstein SL, eds. Lovell and Winters Pediatric Orthopaedics. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2006:695-761.
- Wong E, Altaf F, Oh LJ, Gray RJ. Adult Degenerative Lumbar Scoliosis. Orthopedics. 2017;40(6):e930-e939. doi:10.3928/01477447-20170606-02
- Kyrölä K, Kautiainen H, Pekkanen L, Mäkelä P, Kiviranta I, Häkkinen A. Longterm clinical and radiographic outcomes and patient satisfaction after adult spinal deformity correction. Scand J Surg. 2019;108(4):343–51
- Schwab FJ, Dubey A, Pagala M, Gamez L, Farcy JP. Adult scoliosis: a health assessment analysis by SF-36. Spine (Phila Pa 1976) 2003; 28: 602–06
- Diebo BG, Cherkalin D, Jalai CM, et al. Comparing psychological burden of orthopaedic diseases against medical conditions: Investigation on hospital course of hip, knee, and spine surgery patients. J Orthop 2018; 15: 297–301
- Goldberg CJ, Moore DP, Fogarty EE, Dowling FE. Scoliosis: a review. Ped SurgInt.2008;24:129-144.
- Schoutens C, Cushman DM, McCormick ZL, Conger A, van Royen BJ, Spiker WR. Outcomes of Nonsurgical Treatments for Symptomatic Adult Degenerative Scoliosis: A Systematic Review. Pain Med. 2020;21(6):1263-1275. doi:10.1093/pm/pnz253
- Phan K, Xu J, Maharaj MM, et al. Outcomes of Short Fusion versus Long Fusion for Adult Degenerative Scoliosis: A Systematic Review and Meta-analysis. Orthop Surg. 2017;9(4):342-349. doi:10.1111/os.12357
- Sun W, Gao J, Zhu L, et al. Effect of spinal manipulation on degenerative scoliosis. J Tradit Chin Med. 2020;40(6):1033-1040. doi:10.19852/j.cnki.jtcm.2020.06.015
- Passias PG, Jalai CM, Worley N et al: Adult spinal deformity: National trends in the presentation, treatment, and perioperative outcomes from 2003 to 2010. Spine Deform 2017;5(5):342–350
- Charles YP, Ntilikina Y. Scoliosis surgery in adulthood: what challenges for what outcome?. Ann Transl Med. 2020;8(2):34. doi:10.21037/atm.2019.10.67
- Chen X, Feng F, Yu X, et al. Robot-assisted orthopedic surgery in the treatment of adult degenerative scoliosis: a preliminary clinical report. J Orthop Surg Res. 2020;15(1):282. Published 2020 Jul 25. doi:10.1186/s13018-020-01796-2
- Shimizu T, Lenke LG, Cerpa M, Lehman RA Jr, Pongmanee S, Sielatycki JA. Preoperative halo-gravity traction for treatment of severe adult kyphosis and scoliosis. Spine Deform. 2020;8(1):85-95. doi:10.1007/s43390-019-00017-z
Original Version of the Topic
Aloysia Schwabe, MD, Anand Allam, MD. Scoliosis. 11/14/2011
Andrew I Gitkind, MD, MHA
Nothing to Disclose
Nicole Ortiz, MD
Nothing to Disclose