We searched the MEDLINE, PubMed, and Cochrane Library databases for relevant publications from Jan 1, 2008, to April 12, 2019, using the following search terms: “adult spinal deformity”, “adult scoliosis”, “scoliosis” AND “etiology” OR “epidemiology”, “comorbidity” OR “disease burden”, “evaluation”, “risk stratification”, “treatment planning” OR “treatment outcomes”, “income country”, “treatment disparities”, or “global disparities”. Although a focus was placed on publications in the past 3–5
SeminarAdult spinal deformity
Introduction
Global populations are witnessing an upward shift in societal age distribution because of several factors, including increased longevity, improved medical care, and declining natality.1, 2, 3 In the USA, nearly a quarter of Americans are projected to be older than 65 years by 2060 (>98 million of an estimated population of 417 million), more than double the size of the same age group recorded in 2014 (46 million; 15% of total population).2 This outcome is also shown in global trends; between 1950 and 2000, 12 countries had more than 10 million individuals aged 60 years or older. In this period, the global population of people older than 60 years nearly tripled, from 205 million to 606 million.3
Global demographic shifts have substantially affected the prevalence and burden of musculoskeletal diseases. Adult spinal deformity consists of a heterogeneous spectrum of abnormalities of the lumbar or thoracolumbar spine throughout adulthood.4, 5, 6, 7 The cause of such deformity ranges from de-novo onset to progressive degeneration from pre-existing deformity or accelerated development after previous spinal surgery.4, 5, 8, 9 Spinal deformity is highly prevalent in individuals aged older than 65 years, affecting between 32% and 68% of that population.7, 10, 11 Multiple age-related factors are implicated in its development, including reduced bone mineral density, osteoporosis, spinal degeneration, reduced mobility and balance, and neurodegenerative disorders.1
Spinal deformity has a substantially debilitating effect on patients' general health. Bess and colleagues12 found that patients with no previous spinal surgery have more disabilities than those with hypertension or diabetes, and their disabilities are on par with patients with several types of cancer. Moreover, between 27% and 38% of adults with spinal deformity are psychologically distressed with comorbid mental health disorders.13, 14 This proportion represents a higher overall mental health disorder burden than for patients undergoing short fusions (three spinal levels or less) for degenerative disc disease (18·0–36·5%) or cervical fusion for cervical radiculopathy or myelopathy (23·7%).13, 15, 16 Data also suggest that, despite a similar burden of spinal abnormalities across low-income countries (LICs) and middle-income countries (MICs) to those for high-income countries (HICs), different approaches are required to address the disabling effect of spinal deformity based on inherent differences in health-care delivery infrastructure models.17, 18, 19 Moreover, in the context of an ageing population and increasing burden, economic implications of managing the condition, including variations in surgery-related costs and disparities in care availability, will become of primary importance.20, 21
In this Seminar, we will discuss the current evidence regarding the evaluation and management of adult spinal deformity, with a specific focus on multidisciplinary assessment, risk stratification, treatment methods and disparities between countries, surgical planning, and clinical outcomes.
Section snippets
Aetiology and epidemiology
The spectrum of adult spinal deformities includes de-novo scoliosis, progressive adolescent idiopathic scoliosis in adulthood, hyperkyphosis, iatrogenic sagittal deformity, focal deformity due to multiple degenerative disc disease with global deformity, and post-traumatic spinal deformity (figure 1).4, 5, 8, 9 De-novo scoliosis differs from idiopathic scoliosis in adults in that it develops after skeletal maturity, with a mean age at presentation of 70·5 years and an approximate prevalence of
Disability
In the USA, Schwab and colleagues45 surveyed the burden of disease in patients with adult scoliosis with the Short Form (SF)-36 questionnaire and compared responses to benchmark US general population data and to patients with various medical comorbidities. Adults with scoliosis scored lower in all eight SF-36 domains than the general population data. Furthermore, Bess and colleagues12 obtained SF-36 physical and mental component summary values for adults with symptomatic spinal deformity in the
Social and psychological burden
Related publications have established the effect of chronic medical conditions on treatment outcomes of adults with spinal deformity.54, 55 Yet psychological burden on these patients has only recently been scrutinised.13, 14, 56 Schwab and colleagues45 were among the earliest to describe the statistically significant differences in mental health between patients with scoliosis and the general US population, ranging from 10 points to 30 points in SF-36 mental component summary scales including
Diagnosis
Clinical presentation of adult spinal deformity is heterogeneous. Pain, disability, and neurological complaints are more commonly reported by adult patients than are curve progression or cosmetic deformity, which are more common complaints among adolescent patients.48 Although instances of adult spinal deformity are radiographically identified and remain asymptomatic, patients with symptoms might report a range of pain manifestations, from mild back pain, with or without radiculopathy, to
Biomechanical radiographical analysis to guide treatment planning
Use of free-standing imaging in conjunction with dedicated software has allowed investigators to identify clinically relevant and potentially modifiable parameters. Such an approach has enabled the development of a patient-specific image of the shape of the spine and illustrates changes in alignment and compensation across the assessment and treatment period. Although each spinal deformity is unique, sagittal malalignment, associated with increased disability, can be summarised as the spine
Treatment considerations
Adult spinal deformity can be managed non-operatively or surgically. Non-operative management is regarded as the first-line treatment, despite an absence of strong supporting evidence for non-surgical treatment methods.8, 79, 80 Many of these non-surgical methods can be used as monotherapy or in various combinations, with a goal of managing pain and maintaining function.8 A sparse amount of evidence exists to support the recommendation of physical therapy, superficial heat, stretching, and
Global disparities in treatment
The World Bank currently classifies countries by estimated gross national income (GNI) per capita into four categories: LIC (GNI<$995), LMIC (GNI=$996–3895), upper-middle-income (UMIC; GNI=$3896–12 055), or HIC (GNI >$12 056).108 When considering patient populations in LICs and LMICs several traits of these countries should be thought through when treating adult spinal deformity, including metabolic considerations, such as nutritional-related rickets or acute and chronic malnutrition, and
Surgical planning and risk stratification
When surgical management has been selected, effective preoperative planning requires the creation of an individualised surgical plan and the consideration of patient-specific risk factors that might affect their postoperative course. Several radiographical indices have been identified as pragmatic in determining patient-specific alignment targets for surgical planning.126 Work in risk stratification has augmented surgical planning to permit surgeons to identify surgically modifiable parameters
Treatment outcomes
Much work has been done to improve the understanding of post-treatment course to establish data to assist clinicians and patients in optimising post-treatment expectations. Most publications about adult spinal deformity comparing both operative and non-operative treatment pathways favour surgical intervention (figure 6).92, 93, 94, 95, 96, 134 Liu and colleagues135 showed that patients who received operative interventions reported statistically significant improvements in all HRQoLs and were
Future directions
Dissociation of the driver of spinal deformity from compensatory mechanisms is an important component of individualised preoperative planning for adult spinal deformity. Future evaluation and treatment will focus on how to identify dynamic, rather than purely static, parameters and identify correlations with functional performance and perceived disability. As such, 3D motion analysis with sophisticated gait and motion laboratories could provide clinicians with a wealth of data related to
Conclusion
Adult spinal deformity represents a spectrum of pathologies that mainly affect the thoracolumbar spine of patients throughout the ageing process. Adolescent deformities taken into adulthood are not uncommon, but the most common causes of adult spinal deformity are iatrogenic flatback and degenerative scoliosis. Adult spinal deformity is of growing interest in health care because of its prevalence in patients older than 65 years, a population that is expanding because of increased longevity,
Search strategy and selection criteria
References (140)
- 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) - et al.
What low back pain is and why we need to pay attention
Lancet
(2018) - et al.
Low back pain: a call for action
Lancet
(2018) - et al.
Total hospital costs of surgical treatment for adult spinal deformity: an extended follow-up study
Spine J
(2014) Degenerative scoliosis. Options for surgical management
Orthop Clin North Am
(2003)- et al.
Degenerative lumbar scoliosis associated with spinal stenosis
Spine J
(2007) - et al.
Randomised trial of effect of alendronate on risk of fracture in women with existing vertebral fractures
Lancet
(1996) - et al.
Clinical and radiographic evaluation of the adult spinal deformity patient
Neurosurg Clin N Am
(2013) - et al.
Sagittal alignment of the spine: what do you need to know?
Clin Neurol Neurosurg
(2015) - et al.
The EOS 2D/3D X-ray imaging system: a cost-effectiveness analysis quantifying the health benefits from reduced radiation exposure
Eur J Radiol
(2013)