Imaging of painful scoliosis
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- Davies, A. & Saifuddin, A. Skeletal Radiol (2009) 38: 207. doi:10.1007/s00256-008-0517-5
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Scoliosis is defined as a lateral deviation of the spine from the normal plumb line. Commonly, there is a rotational component and deviation also in the sagittal plane (kyphosis or hyperlordosis). When scoliosis presents in adults, it is often painful. In contrast, back pain in a child is considered rare, and serious underlying pathology should be excluded, particularly since idiopathic scoliosis is typically painless. A painful scoliosis in a child or adolescent, especially if the patient has a left-sided curve, should be examined thoroughly. The aim of this review is to illustrate the causes of a painful scoliosis in children, adolescents and adults.
KeywordsPainful scoliosisIdiopathic scoliosisVertebral tumoursAdult scoliosisOsteoid osteomaOsteoblastomaSpondylosisSpondylolisthesisIntra-spinal tumours
Scoliosis is defined as a lateral deviation of the spine from the normal plumb line. Commonly, there is a rotational component and deviation also in the sagittal plane (kyphosis or hyperlordosis).
When scoliosis presents in adults, it is often painful. In contrast, back pain in a child is considered rare, and serious underlying pathology should be excluded, particularly since idiopathic scoliosis is typically painless. A painful scoliosis in a child or adolescent, especially if the patient has a left-sided curve, should be examined thoroughly.
A review of the literature suggests that the association of pain and underlying pathology in idiopathic scoliosis has not been well documented. The most comprehensive study into this was carried out by Ramirez et al. . In their retrospective review of 2,442 patients with idiopathic scoliosis, 560 patients had back pain at the time of diagnosis, and of these, only 9% were shown to have an underlying pathological condition . Causes included spondylolysis or spondylolisthesis, Scheuermann kyphosis, syrinx/hydromyelia, herniated disc, tethered cord and intra-spinal tumour in decreasing order of incidence. Smaller case series have demonstrated much higher incidences of underlying pathology, with osteoid osteomas (OOs) and osteoblastomas (OBs) being frequent findings [2, 3]. The likely reason for this wide variation in reported incidence of underlying pathology is the differences in defining incidence of pain in these patients.
The aim of this review is to illustrate the causes of a painful scoliosis in children, adolescents and adults.
Plain radiography is recommended as the initial investigation in patients with scoliosis. This allows the diagnosis and also the evaluation of the degree of curvature by measuring the Cobb angle. Underlying osteogenic anomalies can also be identified, which can help direct further imaging.
Multi-detector computed tomography (CT) with 2D multi-planar reformatting and 3D reconstruction are important in the pre-operative evaluation of vertebral abnormalities due to anomalous formation or segmentation of the vertebral column. In addition, CT is valuable in the assessment of vertebral tumours as it is superior to magnetic resonance imaging (MRI) at evaluating cortical bone destruction and the calcified tumour matrix. In addition, it gives greater detail of subtle abnormalities of the neural arch.
MRI is the imaging modality of choice for assessment of the contents of the spinal canal, allowing direct, non-invasive imaging of the entire vertebral column, including the cord and other spinal canal contents. It has been shown to be more sensitive and specific in the assessment of intra-spinal anomalies when compared to myelography [4, 5]. The whole of the spine must be imaged using a combination of T1- and T2-weighted sequences (without and with fat suppression), with the aim of identifying any correctable causes for the scoliosis. In addition, T1-weighted images after the administration of gadolinium should be considered, especially if there is a cord tumour.
The role of 99m-technetium methylene diphosphonate (MDP) bone scintigraphy is now diminishing, but it may still be of value in the assessment of OO.
Classification of scoliosis
Aetiological classification of scoliosis
Infantile (0–3 years)
Juvenile (3–10 years)
Adolescent (>10 years)
Neuropathic (spinal dysraphism)
Upper motor neurone
Lower motor neurone
Duchene muscular dystrophy
Skeletal dysplasias (e.g. osteogenesis imperfecta)
Skeletal dystosis (e.g. neurofibromatosis)
Aneurysmal bone cyst
Langerhans cell histiocytosis
Extra-medullary (e.g. neurofibroma)
Intra-medullary (e.g. astrocytoma)
Causes of painful scoliosis
Potential causes of a painful scoliosis
Aneurysmal bone cyst
Langerhans cell histiocytosis
Extra-medullary (e.g. neurofibroma)
Intra-medullary (e.g. astrocytoma)
Facet joint arthritis
Nerve root compression
OO was first described in 1935 as a distinct pathological entity . The majority of cases occur in patients under 25 years of age, with 20% occurring in the spine. The commonest location is in the lumbar region (59%) with the nidus found in the neural arch in the majority of patients [9–11].
OB is a rare tumour that accounts for less than 1% of all bone tumours . However, more than 40% of cases are located in the spine , where it usually involves the neural arch [29–31]. Involvement of the vertebral body is extremely rare but can present with similar symptoms and deformity [32–34]. There may be some delay in diagnosis, especially in adolescents who have some degree of scoliosis with no obvious radiological abnormality. Back pain is always the presenting symptom, and more than 50% of patients present with an associated spinal deformity . A structural scoliosis may occur in approximately 31% of patients due to the delay in diagnosis and treatment .
Differentiation from OO is based mainly on the size of the lesion and its behaviour. Various authors have suggested that lesions above 1 , 1.5  or 2 cm  should be classified as OB. However, lesions that have destroyed the cortex and produced an extra-osseous mass should be classified as OB regardless of size, since this growth pattern is not a feature of OO .
OB is confined to the neural arch of the vertebra in approximately 66% of cases, but the extension from the pedicle into the posterolateral aspect of the vertebral body is not uncommon . Lesions confined to the vertebral body are rare, occurring in approximately 3% of cases .
On scintigraphy, OB demonstrates non-specific but intense, well-defined focal increased activity . A negative bone scan has never been reported in patients with spinal OO or OB.
Aneurysmal bone cyst
Aneurysmal bone cyst (ABC) is a benign cystic bone lesion, which represents either a true primary tumour or may develop within a pre-existing lesion (e.g. giant cell tumour, chondroblastoma). Patients with ABC usually present before 20 years of age, and the spine is involved in approximately 11% of cases, most commonly at the lumbar level .
Spinal lesions frequently present with neurological symptoms. Pain is invariably present and is either localised to the back or is secondary to the involvement of a nerve root or the spinal cord . Plain radiographs (Fig. 9b) and CT (Fig. 9c) demonstrate a lytic expansile lesion associated with cortical thinning or loss . The lesion margins are usually well defined and commonly scalloped (Fig. 9c) but appear poorly defined in approximately 14% of cases. Fluid–fluid levels can be seen, optimally on sagittal or axial T2-weighted MRI (Fig. 9d), with MRI providing a better assessment of spinal canal extension and the degree of nerve root or cord compression . Enhancing septae may also be seen on MRI following intra-venous gadolinium.
Langerhans cell histiocytosis
Langerhans cell histiocytosis (LCH) is a tumour-like lesion originating from the over-production and accumulation of histiocytes. The estimated incidence is 1 per 200,000 . In the spine, LCH most commonly involves the vertebral bodies, frequently in a multi-focal manner . The involvement of the neural arch is very rare. LCH is most common in the first or second decades of life with a mean age of 6.4 years at presentation . The most common complaint is pain, especially at night. When LCH involves the spine, it normally causes only localised neck or back pain, with neurological symptoms being rare and usually limited to mild parasthaesia or radiculopathy . The thoracic vertebrae are most commonly involved, with the disc spaces preserved [47, 48]. Spinal involvement results in variable degrees of collapse with the most severe appearance being complete vertebra plana , and LCH is the most common cause of vertebra plana in children [47, 49]. However, it can rarely appear as a hemivertebra with resultant scoliosis . MRI findings in LCH are non-specific and can simulate other bone lesions including osteomyelitis, OB and Ewing sarcoma [51, 52]
Malignant tumours and infection
Tuberculous (TB) spondylodiscitis is the most common site for osseous involvement by TB , with spinal involvement seen in up to 15% of cases. The clinical presentation is mainly of insidious pain (42%) . With non-TB spondyodiscitis, the spine is involved by infectious organisms through hematogenous spread or from a contaminated contiguous source , the lumbar level being most frequently involved. An initial scoliosis may be non-structural due to pain, but if the infection remains untreated, vertebral destruction can result in kyphosis or less frequently scoliosis.
Spinal cord tumours can present as scoliosis without neurological signs, which can take years to develop [55, 56]. In a large series of 115 intra-spinal tumours, scoliosis was the presenting abnormality in 31 cases . Inoue et al. found statistically significant differences in the presence of neuraxis malformations in scoliosis patients with moderate or severe pain compared to those whose scoliosis was pain-free .
Ependymomas and astrocytomas constitute up to 70% of intra-medullary neoplasms. Spinal cord ependymomas are the most common type in adults, whilst asrocytomas are more common in children .
Cord ependymomas occur most commonly in the cervical region with 44% involving the cervical cord and an additional 23% extending into the upper thoracic region . Radiographs may demonstrate a scoliosis in up to 16% of cases, and canal widening with associated vertebral body scalloping, pedicle erosions or laminar thinning can also be demonstrated . Most spinal cord ependymomas are iso- or hypo-intense relative to the cord on T1-weighted MRI images [61–63], whilst on T2-weighted images, iso-intense tumours are as common as hyper-intense tumours . Approximately 20–33% of ependymomas demonstrate the ‘cap sign,’ a rim of extreme hypo-intensity at the poles on T2-weighted images. This is thought to be secondary to haemorrhage [62, 64]. Cysts are also a common feature, with 78–84% of ependymomas having at least one cyst, most of these being of the non-tumoural (polar) variety [61–63].
Astrocytomas (Fig. 12) most commonly involve the thoracic cord (67%) . Scoliosis is seen in 24% of cases, with radiographs also demonstrating bony canal expansion, although this occurs less commonly than with ependymoma . On MRI, astrocytomas are usually eccentrically located within the cord (57%), are ill defined and show heterogeneous enhancement [64, 65]. Cysts are a common feature, with both non-tumoural and tumoural types seen . Even with these differences, it may not be possible to differentiate between the two entities on the basis of imaging features alone.
Syringomyelia occurs with congenital abnormalities, trauma or infection or may be associated with tumour or arachnoididitis. Hydromyelia refers to the dilatation of the central canal that is lined by the ependyma, whereas syringomyelia represents the dissection of cerebrospinal fluid (CSF) into the cord substance. The two conditions may not be distinguishable on MRI, or they may co-exist, and as such, the combined term syringohydromyelia is often used.
Seventy percent of patients with syringohydromyelia have an associated scoliosis , but little is known about the pain patterns in such patients. However, a study by Ozerdemoglu et al. found that 70 of 119 patients (59%) with syringomyelia associated scoliosis had pain at presentation. Backache, headache and neck pain were the most common types of pain. Leg pain was found predominantly in patients with a terminal syrinx. There was no apparent correlation between syrinx size and pain .
In the absence of an underlying vertebral tumour/infection or intra-spinal abnormality, the aetiology of painful scoliosis is poorly understood. It is thought to include muscular pain due to eccentric loading about the curve apex, asymmetric facet joint loading resulting in facet joint degeneration or synovitis, discogenic pain or a combination of these .
Disc degeneration is seen to occur at the concave aspects of scoliotic discs [69–72]; however, its progression to discogenic pain is poorly understood. A study looking at the relationship of degenerative disc findings on MRI in scoliosis patients found that overall disc degeneration was similar in patients with painful scoliosis and asymptomatic control subjects . However, in the paediatric scoliosis patients, those with Schmorl’s nodes and inflammatory end-plate changes had more significant pain than those without, suggesting that symptoms in scoliosis patients may, in part, have a discogenic etiology. Disc herniation is a rare cause of pain in the scoliosis patient, with no evidence to suggest a higher incidence of disc herniation between patients with scoliosis and the general population .
Scheurmann’s diseases is a condition defined by vertebral wedging, end-plate irregularity and narrowing of the inter-vertebral disc space with or without disc prolapse and intra-vertebral disc herniation (Schmorl’s nodes) . These changes classically result in thoracic spinal kyphosis. It is a condition of adolescents and young adults and is relatively common, found in 31% of boys and 21% of girls with back pain . The etiology of Scheurmann’s disease is unknown. Scheuermann proposed that the kyphosis resulted from avascular necrosis of the ring apophysis of the vertebral body . Schmorl suggested that the vertebral body wedging was caused by herniation of disc material into the vertebral body. Mechanical factors and repetitive trauma have also been considered to play a significant role . It is likely that the etiology is multi-factorial. The criteria for the diagnosis of Scheuermann’s disease are: (1) greater than 5° of wedging of at least three adjacent vertebrae at the apex of the kyphosis, (2) end-plate irregularities and (3) a thoracic kyphosis of more than 45° [75–77].
Classification of adult degenerative scoliosis
Type 1. Primary degenerative scoliosis, mostly on the basis of a disc and/or facet joint arthritis, affecting those structures asymmetrically with predominantly back pain symptoms
Type 2. Progressive idiopathic scoliosis in adult life of the thoracic and or lumbar spine, which progresses in adult life and is usually combined with secondary degeneration
Type 3. Secondary degenerative scoliosis
a. Scoliosis following idiopathic or other forms of scoliosis or occurring consequent on pelvis obliquity secondary to leg length discrepancy, hip pathology or a lumbosacral spine
b. Scoliosis secondary to metabolic bone disease (predominantly osteoporosis) combined with asymmetric arthritic disease and/or vertebral fractures.
In the context of evaluating the pain source in these patients, image-guided facet and nerve root blocks and discography can help in surgical planning, and if surgery is not feasible, then facet joint and nerve root injections may be used as a therapeutic tool .
Painful scoliosis has a variety of causes. The scoliosis can be secondary to an underlying pathological cause, e.g. vertebral tumour. The associated scoliosis in this instance can be non-structural due to muscle spasm induced by the painful lesion; if the diagnosis is delayed, then the scoliosis may assume a structural component with vertebral rotation. Unilateral vertebral destruction by tumour or infection can also result in a structural scoliosis. There should be a high index of suspicion in a child with a presumed idiopathic scoliosis presenting with significant back pain, and a careful search should be carried out for any radiological evidence of an underlying cause. It should be remembered that intra-spinal lesions can cause a painful scoliosis without any neurological signs. In other instances, back pain can be secondary to the scoliosis, e.g. discogenic or facet degeneration. This is especially true in adult scoliosis where back pain is the predominant symptom due to spinal degeneration. However, other causes of a painful scoliosis should not be missed in this group, such as scoliosis secondary to vertebral metastases or myeloma.