The Spine

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Chapter 671 The Spine

Abnormalities of the spine may be present at birth (congenital), can develop during childhood or adolescence, or can result from traumatic injuries. Alterations in spinal alignment are commonly of cosmetic concern to the patient and family. Sequelae from progressive spinal deformities include pain, cardiopulmonary dysfunction, and a loss of sitting balance (nonambulators). Early detection helps to facilitate treatment and to identify and address coexisting visceral and/or neurologic problems that may be associated with a spinal deformity. A classification of common spinal abnormalities is presented in Table 671-1.

Scoliosis is a complex three-dimensional deformity that is most commonly described as a lateral curvature of the spine in the frontal plane. Most cases of scoliosis have no demonstrable etiology, and are termed idiopathic. Scoliosis may be congenital or may be associated with a host of neuromuscular diseases or syndromes. Scoliosis may also be secondary to an infrapelvic deformity such as a leg-length discrepancy or a soft-tissue contracture around the hip (abduction or adduction).

In the lateral (sagittal) plane, the spine has normal curvatures in the cervical (lordotic or convex anteriorly), thoracic (kyphosis or convex posteriorly), and lumbar (lordosis) regions to maintain the relationships of body segments relative to the forces of gravity. Maintaining the center of gravity is important for balance and to minimize the amount of muscular activity (conserve energy) required to maintain upright posture. A vertical (gravity) line dropped from the 7th cervical vertebra should normally fall through the posterosuperior corner of the sacrum. Disorders of sagittal alignment include thoracic hyperkyphosis and lumbar hyperlordosis. Thoracic hyperkyphosis is seen most commonly in patients with postural kyphosis or with Scheuermann disease. Lumbar hyperlordosis may be associated with spondylolisthesis or may be secondary to hip flexion contractures.

671.1 Idiopathic Scoliosis

Etiology and Epidemiology

Scoliosis is a complex, 3-dimensional deformity of the spine, with abnormalities in the coronal, sagittal, and axial planes. The diagnosis is based on a coronal plane curvature of >10 degrees using the Cobb method. Idiopathic scoliosis is a diagnosis of exclusion; other causes must be ruled out (see Table 671-1). The etiology of idiopathic scoliosis remains unknown and is likely multifactorial, involving both genetic and environmental components. Major theories have been based on genetic factors, metabolic dysfunction (melatonin deficiency, calmodulin), neurologic dysfunction (craniocervical, vestibular and oculovestibular), and biomechanical factors (asynchrony in spinal growth, anterior spinal overgrowth, and others). With regard to genetic factors, although several different modes of inheritance have been suggested (autosomal dominant, multifactorial, X-linked), a single locus has yet to be identified. Abnormalities identified in connective tissue, muscle, and bone appear to be secondary. Melatonin and calmodulin might have indirect effects, and subtle abnormalities in vestibular, ocular, and proprioceptive function suggest that abnormal equilibrium might also play a role.

Idiopathic scoliosis is classified according to the age at onset, including infantile (rare, birth to 3 yr), juvenile (3-10 yr), and adolescent (≥11 yr). Adolescent idiopathic scoliosis (AIS) is most common (∼70%). The prevalence of scoliosis (>10 degrees curvature) is ∼2-3%; however, approximately 0.3% have a curve >30 degrees. The incidence is roughly equal in girls and boys for small curves (<10 degrees), but girls have 10 times the risk of developing a curvature >30 degrees.

Clinical Manifestations

Patients usually present with a change in cosmetic appearance noted by family and/or friends or on a screening examination by a school nurse or primary care physician. The patient is evaluated in the standing position, from both the front and the side, to identify any asymmetry in the chest wall, trunk, and/or shoulders. Asymmetry of the posterior chest wall on forward bending (the Adams test) is the earliest abnormality (Fig. 671-1). Rotation of the vertebral bodies toward the convexity results in rotation and prominence of the attached ribs posteriorly. The anterior chest wall may be flattened on the concavity, due to inward rotation of the chest wall and ribs. Associated findings can include elevation of the shoulder, a lateral shift of the trunk, and an apparent leg-length discrepancy. The patient should also be evaluated from the side. The thoracic spine normally has a smooth, rounded kyphosis (20-50 degrees using the Cobb method from T3-T12) that extends down to the thoracolumbar junction, and the lumbar spine is normally lordotic (30-60 degrees using the Cobb method from T12-L5). Children normally have less cervical lordosis and more lumbar lordosis than do adults or adolescents. Typically, idiopathic scoliosis results in a loss of the normal thoracic kyphosis in the region of curvature (relative thoracic lordosis).

A careful neurologic examination should always be performed. A subset of curves are associated with an underlying neurologic diagnosis, especially in patients who present in the infant and juvenile years (20% have an associated intraspinal abnormality). The index of suspicion is raised in the presence of back pain or neurologic symptoms, café-au-lait spots, a sacral dimple or midline cutaneous abnormalities (hemangioma, hair patch or skin tag), unilateral foot deformity, or an atypical curve pattern. The examiner should always test the superficial abdominal reflex by lightly stroking the skin on both sides of the umbilicus. Normally, the umbilicus should deviate toward the side that was stroked. Asymmetry of the superficial abdominal reflex (or unilateral absence of this reflex) might suggest syringomyelia as an underlying diagnosis.

Screening for scoliosis facilitates earlier diagnosis and treatment, under the assumption that the natural history may be influenced by bracing, and that earlier identification of cases suitable for surgery reduces the complexity and risks of the surgery. Screening may be accomplished during primary care visits or as part of a school screening program. A consensus statement from professional societies (American Academy of Pediatrics, American Academy of Orthopaedic Surgeons, Pediatric Orthopaedic Society of North America, and the Scoliosis Research Society) states that if screening is to be carried out, this should be at 10 and 12 years of age for girls, and once at 13-14 years for boys. The Adams forward-bend test has been used to identify any asymmetry in the thoracic and/or lumbar region, and an inclinometer (scoliometer, Orthopaedic Systems Inc.) is also used to measure the degree of asymmetry. The number of degrees used for referral typically varies from 5 to 7, and the referral rate from these programs varies from 3% to 30%. School screening remains controversial, and less than half of the states in the USA have formal programs. The U.S. Preventive Services Task Force (USPSTF) has recently recommended against school screening in 2004, and further research is required to inform policy.

The natural history of idiopathic scoliosis varies considerably based on the age at diagnosis. Curvatures in excess of 80 degrees can result in restrictive pulmonary disease, and larger curves in excess of 100-120 degrees can result in a reduced life expectancy, due to cor pulmonale and cardiorespiratory failure. Scoliotic curves diagnosed in infancy through childhood are much more likely than adolescent curves to reach this magnitude. In general, adults with untreated AIS are expected to have similar life expectancy and similar functional activities, and no greater risk of cardiopulmonary complications, when compared with age-matched controls. Back pain may be more common, but it does not appear to be more disabling. Thoracolumbar or lumbar curves are more likely to cause pain during adulthood, particularly if there is an associated translational shift of the vertebrae. Dyspnea is common with thoracic curves of >80 degrees. Thoracic curves <30 degrees rarely progress after skeletal maturity, but those >45 or 50 degrees can continue to progress at approximately 1 degree per year through life. The cosmetic aspects of the deformity may be the most significant concern for the majority of patients with untreated AIS.

Radiographic Evaluation

Standing high-quality posteroanterior (PA) and lateral radiographs of the entire spine are recommended at the initial evaluation for patients with clinical findings that suggest a spinal deformity. On the PA radiograph, the degree of curvature is determined by the Cobb method, in which the angle between the superior and inferior end vertebra (tilted into the curve) is measured (Fig. 671-2). A line is drawn across the superior end plate of each end vertebra, and the angle between perpendicular lines erected from each of these is measured. Although the indications for performing MRI are variable, this modality is helpful when an underlying cause for the scoliosis is suspected based on age (infantile, juvenile curves), abnormal findings on the history and physical examination, and atypical radiographic features (curve patterns and/or specific features). Atypical radiographic findings include uncommon curve patterns such as the left thoracic curve, double thoracic curves, high thoracic curves, widening of the spinal canal, and erosive or dysplastic changes in the vertebral body or ribs. On the lateral radiograph, an increase in thoracic kyphosis or an absence of segmental lordosis might suggest the presence of an underlying diagnosis.

image

Figure 671-2 A-C, Cobb angles measurements.

(From Morrissy, RT, Weinstein, SL: Lovell & Winter’s pediatric orthopaedics, ed 6, Philadelphia, 2006, Lippincott Williams & Wilkins.)

Treatment

Options for treatment include observation, bracing, and surgical treatment. Treatment decisions are based on the natural history of each curvature, which relates to age (degree of skeletal maturity or growth remaining), the magnitude of the curve, and occasionally associated diagnoses and/or medical considerations. A positive family history does not help predict the behavior of an individual curve. Observation is always indicated for curvatures <20 degrees. Curves of larger magnitude may be treated by bracing or surgery. The risk of curve progression depends on the amount of growth remaining, the curve’s magnitude, and gender. More than one parameter must be used when determining the amount of growth remaining, and both clinical (age, annual growth velocity, menarchal status, Tanner stage) and radiographic (Risser sign, skeletal age, maturation of olecranon apophysis) measures are available. Curves are more likely to progress if there is significant growth remaining (premenarchal, Tanner stage I or II, Risser 0 or 1). Premenarchal girls with curves between 20 and 30 degrees have a significantly higher risk of progression than do girls 2 yr after menarche with similar curves. Boys with curvature of the same magnitude appear to have similar risks of progression when judged by other maturation standards; however, the assessment of skeletal maturity in boys is more difficult.

Bracing

The goal of bracing is to prevent progression of the deformity, thereby reducing the need for surgery. The efficacy of bracing in AIS remains controversial, but most centers in North America offer a brace to selected patients with progressive curvatures. In AIS, the typical indications for bracing are a curve >30 degrees, or a curve from 20-25 degrees that has progressed >5 degrees, in a skeletally immature patient (Risser 0,1, or 2). Bracing is thought to be ineffective in curves >45 degrees. An “in brace” correction of 50% in Cobb angle is desirable.

The success of bracing is thought to increase with greater time spent in the brace, and the ideal program includes 23 hours in the brace per day. Protocols vary between 16 and 23 hours per day, recognizing that full compliance is difficult to achieve in the adolescent population. Bracing is commonly used as a temporizing measure for infantile and juvenile scoliosis given the high likelihood of significant progression, and the need to delay more definitive treatment. The success rate is much lower for infantile and juvenile curvatures, but the goal is to delay progression.

There are several options for braces (Fig. 671-3). The Milwaukee brace, employing longitudinal traction from the skull to the pelvis with lateral compression of the chest wall, can be adjusted for growth and thus is a good brace for patients with infantile or juvenile scoliosis. Underarm braces (the Boston or Wilmington braces) are less obvious and so are often preferred by adolescents. The Charleston brace provides a corrective force and is used only at night.

image

Figure 671-3 Various brace types.

(From Morrissy, RT, Weinstein, SL: Lovell & Winter’s pediatric orthopaedics, ed 6, Philadelphia, 2006, Lippincott Williams & Wilkins.)

Surgery

Surgical treatment is indicated for the majority of patients with infantile or juvenile idiopathic scoliosis and in selected patients with AIS, when other methods of treatment have failed to control the deformity, and when further progression would be expected to result in unacceptable cosmesis and/or physiologic abnormalities. Such deformities are typically treated by a definitive spinal arthrodesis (fusion). The majority of progressive infantile and juvenile curves ultimately require a spinal arthrodesis, and the goal is to delay the definitive procedure until the pulmonary system and thoracic cage have matured and the trunk height has been maximized.

An alternative strategy is required for curvatures that progress despite bracing. In some centers, serial casting under general anesthesia is employed for selected infantile and juvenile curves to gain correction into a “braceable” range, followed by application of a spinal orthosis. The other option for progressive curvatures is a “growing rod” construct. A spinal rod (or 2 rods) is attached to anchors at the top and at the bottom of the curvature, and distraction forces are applied to achieve correction. The rods hold the spine in the corrected position, and they must then be lengthened every 6 months to maintain correction. Many curves have been controlled for years using such a protocol, and definitive fusion is delayed until a more optimal age.

With regard to AIS, surgical treatment is usually indicated for skeletally immature patients with progressive thoracic curves >45 degrees and skeletally mature patients with thoracic curves >50-55 degrees. Lumbar curves are more likely to progress, and surgical stabilization may be offered for curves as low as 35-40 degrees if there is a significant shift of the trunk relative to the pelvis and lower extremities. The goals of surgery are to arrest progression of the deformity, to improve cosmesis, and to minimize the number of vertebral segments that are stabilized. These are achieved through a spinal fusion or arthrodesis, and implants are used to apply mechanical forces to the bony elements to affect correction and to hold the spine in the corrected position until the spine fuses. Postoperative immobilization is usually not required. Options for bone grafting include autograft (iliac crest) or allograft, and in recent years most surgeons have used cancellous allograft with or without enhancers such as demineralized bone matrix.

The most common procedure is an instrumented posterior spinal fusion, and the typical spinal implant construct includes 2 rods anchored to the spine by hooks, wires, and/or screws (Fig. 671-4). In the last few years there has been significant interest in using a construct with pedicle screws at each level. Although correction of the axial deformity (rotation of the rib cage) is more pronounced with this technology, it remains unclear whether patient outcomes are improved. An anterior release and fusion, performed through a thoracotomy or thoracolumbar exposure, is indicated for isolated thoracolumbar and lumbar curves, to improve correctability of stiffer curves, and to prevent curve progression (“crankshaft”) from continued anterior growth of the spine in selected patients with considerable growth remaining. A construct with multiple pedicle screws can allow the surgeon to avoid an anterior approach in many larger or stiffer curves (more powerful correction) and in younger patients (stiff enough to resist anterior spinal growth and prevent crankshaft). Thoracoscopic surgery has also been used to perform an anterior release with or without instrumentation and fusion, but this technique has been used much less often since the advent of thoracic pedicle screws. For idiopathic thoracolumbar and lumbar curves, an anterior fusion with instrumentation (usually screws in the vertebral body connected to 1 or 2 rods) can be done as an alternative to save lumbar motion segments.

There has been an interest in developing techniques to tether spinal growth, most commonly by placing metallic staples across each disk space on the convexity of a curvature. The goal is to slow or arrest growth on the convexity while allowing growth to proceed on the concavity, thereby preventing progression and possibly resulting in permanent correction without the need for an arthrodesis. The indications for this technique, and the long-term results, remain to be determined.

Bibliography

Barsdorf AI, Sproule DM, Kaufman P. Scoliosis surgery in children with neuromuscular disease. Arch Neurol. 2010;67:231-235.

Bunge EM, Juttmann RE, van Biezen FC, et al. Estimating the effectiveness of screening for scoliosis: a case-control study. Pediatrics. 2008;121:9-14.

de Lind van Wijngaarden RFA, de Klerk LWL, Festen DAM, et al. Scoliosis in Prader-Willi syndrome: prevalence, effects of age, gender, body mass index, lean body mass and genotype. Arch Dis Child. 2008;93:1012-1016.

Dolan LA, Weinstein SL. Surgical rates after observation and bracing for adolescent idiopathic scoliosis: an evidence based review. Spine. 2007;32:S91-S100.

Gillingham B, Fan RA, Akbarnia BA. Early onset idiopathic scoliosis. J Am Acad Orthop Surg. 2006;14:101-112.

Kallmes D, Jarvik JG. Spinal augmentation research: free at last? Lancet. 2009;373:982-984.

Katz DE, Herring JA, Browne RH, et al. Brace wear control of curve progression in adolescent idiopathic scoliosis. J Bone Joint Surg Am. 2010;92:1343-1352.

Kim YJ, Lenke LJ, Kim J, et al. Comparative analysis of pedicle screw versus hybrid instrumentation in posterior spinal fusion of adolescent idiopathic scoliosis. Spine. 2006;31:291-298.

Merola AA, Haher TR, Brkaric M, et al. A multi-center study of the outcomes of the surgical treatment of adolescent idiopathic scoliosis using the Scoliosis Research Society (SRS) outcome instrument. Spine. 2002;27:2046-2051.

Negrini S, Minozzi S, Bettany-Saltikov J, et al: Braces for idiopathic scoliosis in adolescents (review), Cochrane Database Rev (1):CD006850, 2010.

Richards BS, Vitale MG. Screening for idiopathic scoliosis in adolescents. An information statement. J Bone Joint Surg Am. 2008;90:195-198.

Tones M, Moss N, Polly DWJr. A review of quality of life and psychosocial issues in scoliosis. Spine. 2006;31:3027-3028.

Weinstein SL, Dolan LA, Cheng JCY, et al. Adolescent idiopathic scoliosis. Lancet. 2008;371:1527-1536.

Weinstein SL, Dolan LA, Spratt KF, et al. Health and function of patients with untreated idiopathic scoliosis. JAMA. 2003;289:559-567.

Wright JG, Donaldson S, Howard A, et al. Are surgeon’s preferences for instrumentation related to outcomes? A randomized clinical trial of two implants for idiopathic scoliosis. J Bone Joint Surg Am. 2007;89:2684-2693.

671.2 Congenital Scoliosis

Congenital scoliosis results from abnormal growth and development of the vertebral column, likely due to intrauterine events at or about the 6th wk of gestation. There can be a partial or complete failure of formation (wedge vertebrae or hemivertebrae), a partial or complete failure of segmentation (unilateral unsegmented bars), or a combination of both (Fig. 671-5). One or more bony anomalies can occur in isolation or in combination.

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Figure 671-5 The defects of segmentation and formation that can occur during spinal development.

(From McMaster MJ: Congenital scoliosis. In Weinstein SL, editor: The pediatric spine: principles and practice, ed 2, Philadelphia, 2001, Lippincott Williams & Wilkins, p 163.)

As the spine (including the neural elements) and the viscera are formed around the 6th week in utero, patients with congenital scoliosis often have visceral and intraspinal anomalies as well. Once a congenital spinal anomaly is diagnosed, a priority is to rule out malformations in other organ systems. Genitourinary abnormalities are identified in 20-40% of children with congenital scoliosis and include unilateral renal agenesis, ureteral duplication, horseshoe kidney, and genital anomalies. Approximately 2% of these patients have a silent obstructive uropathy that may be life threatening. Renal ultrasonography should be performed early on in all children with congenital scoliosis, and other studies (CT, MRI) may also be required. Cardiac anomalies are identified in 10-25% of patients. A careful cardiac examination should be performed; some clinicians recommend routine echocardiography.

Approximately 20-40% of patients have an intraspinal anomaly. Infants with cutaneous abnormalities overlying the spine might benefit from ultrasonography to rule out an occult spinal dysraphic condition. MRI is usually recommended during the course of treatment. Spinal dysraphism is the general term applied to such lesions (Chapters 585 and 598). Examples include diastematomyelia, split cord malformations, intraspinal lipomas (intradural or extradural), arachnoid cysts, teratomas, dermoid sinuses, fibrous bands, and tight filum terminale. Cutaneous findings that may be seen in patients with closed spinal dysraphism include hair patches, skin tags or dimples, sinuses, and hemangiomas. Most of these lesions become clinically evident through tethering of the spinal cord, the symptoms of which include back and/or leg pain, calf atrophy, progressive unilateral foot deformity (especially cavovarus), and problems with bowel or bladder function.

The risk of progression depends on the growth potential of each anomaly, which can vary considerably, so close radiographic follow-up is required. Progression of these curves is most pronounced during periods of rapid growth, namely, the first 2-3 yr of life and during the adolescent growth spurt. The most severe form of congenital scoliosis is a unilateral unsegmented bar with a contralateral hemivertebra. In this anomaly, the spine is fused on 1 side (unsegmented bar) and has a growth center (hemivertebra) on the other side at the same level. A rapidly progressive curve is seen, and all patients usually require surgical stabilization. A unilateral unsegmented bar is also associated with significant progression and in most cases will require surgical intervention. An unsegmented bar might not be radiographically apparent, but the adjacent ribs on the concavity may be fused, providing a clue to the diagnosis. An isolated hemivertebra must be followed closely, and many of these will be associated with a progressive deformity that requires surgical intervention. In contrast, an isolated block vertebra has little growth potential and rarely requires treatment.

Early diagnosis and prompt treatment of progressive curves are essential. Bracing is not indicated for most congenital curves due to their structural nature, except in rare cases in which the goal is to control a flexible, compensatory curvature in another area of the spine. The treatment of progressive curves is preemptive spinal arthrodesis, and both anterior and posterior spinal fusion is often required. Other procedures that are employed in selected patients include an isolated posterior spinal fusion (sometimes an in situ fusion), convex hemiepiphysiodesis (only 1 side of the spine is fused to allow some correction of the deformity with growth), and partial or complete hemivertebra excision (usually in the lumbar spine). Spinal arthrodesis is ideally performed before a significant deformity has developed because intraoperative correction is difficult to achieve and the risk of neurologic complications is high.

When multiple levels of the thoracic spine are involved, especially in the presence of fused ribs, a progressive 3-dimensional deformity of the chest wall can impair lung development and function, resulting in a thoracic insufficiency syndrome. This syndrome is best described as the inability of the chest wall to support normal respiration. A thoracic insufficiency syndrome may be seen in patients with several recognized conditions, such as Jarcho-Levin syndrome (spondylocostal or spondylothoracic dysplasia) and Jeune syndrome (asphyxiating thoracic dystrophy). There is interest in treating these difficult cases with an experimental technique called expansion thoracoplasty, in which the thoracic cage is gradually expanded over time by progressive lengthening of the chest wall on the concavity of the spinal deformity (or in some cases on both sides of the spine). The procedure involves an opening wedge thoracostomy, followed by placement of a vertical expandable titanium prosthetic rib. The implant is then distracted (lengthened) at regular intervals (Fig. 671-6). The primary goal is to gradually correct the chest wall deformity to improve pulmonary function, and a secondary goal is correction of an associated spinal deformity. This technique is currently not approved for the treatment of scoliosis in the absence of a thoracic insufficiency, and further study will help to refine (and possibly expand) the indications for the technique.

671.3 Neuromuscular Scoliosis, Genetic Syndromes, and Compensatory Scoliosis

Neuromuscular Scoliosis

Scoliosis is often identified in children with neuromuscular diseases such as cerebral palsy, the muscular dystrophies and other myopathies, spinal muscular atrophy, Friedreich ataxia, myelomeningocele, polio, and arthrogryposis. The etiology and natural history differ from those seen in idiopathic and congenital scoliosis. Most cases result from weakness and/or imbalance of the trunk musculature, and spasticity plays a role in many patients as well. Coexisting congenital vertebral anomalies are seen in patients with myelomeningocele. Neuromuscular scoliosis is most common in the nonambulatory population and is diagnosed in up to 68% of nonambulatory patients with cerebral palsy and >90% of patients with Duchenne muscular dystrophy. The most common pattern is a long, C-shaped curve, which is often associated with pelvic obliquity. In general, the clinical course depends on the severity of neuromuscular involvement and the nature of the underlying disease process (especially if it is progressive).

The consequences of a progressive scoliosis in the neuromuscular population involve both function (sitting and standing balance) and ease of care; in some cases, visceral function is compromised. In patients who are wheelchair bound, one arm may be required for trunk support, which impairs upper extremity function. An associated pelvic obliquity results in asymmetric seating pressures, which can limit sitting endurance and possibly result in ischial decubiti. Severe curves may be associated with decreased pulmonary reserve, especially when the apex is in the thoracic spine, compounding pre-existing respiratory problems. Pain may be experienced from impingement of the rib cage on the iliac crest in large thoracolumbar curves. Marginal ambulators can lose the ability to ambulate as a result of scoliosis.

Treatment

The treatment of neuromuscular scoliosis depends on the age of the patient, the underlying diagnosis, and the degree of progression. The goal is to achieve or maintain a straight spine over a level pelvis, especially in patients who are wheelchair bound, and to intervene early before curve magnitude and rigidity increase. In contrast to idiopathic and congenital scoliosis, neuromuscular curves can continue to progress after skeletal maturity. In general, curves of >40-50 degrees will continue to worsen over time.

Although brace treatment will not arrest progression in the long term, this strategy can help to slow the rate of progression until more definitive treatment can be carried out. Because the standard braces used for idiopathic scoliosis are poorly tolerated in neuromuscular patients, a soft spinal orthosis or seating modifications are often recommended. In addition to delaying progression, these orthoses improve sitting balance (upper extremity function), sitting tolerance, and ease of care.

In general, a spinal arthrodesis is offered to patients with progressive curvatures >40-50 degrees. The indications differ somewhat based on the underlying diagnosis. Patients with Duchenne muscular dystrophy are offered surgery when their curves progress beyond 20-30 degrees, before a significant decline in pulmonary or cardiac function preclude their ability to tolerate the surgery. There has been some controversy regarding the indications for spinal fusion in the patient with spastic quadriplegia, especially in patients with severe mental retardation. In this population, the indications must be individualized and typically involve a documented loss of function or ease of care or chronic discomfort. Patients with curves similar to those seen in idiopathic scoliosis are usually ambulatory and are managed by similar principles and surgical techniques. Patients who are nonambulatory, often with pelvic obliquity, are usually managed by a spinal fusion extending from the upper thoracic spine to the pelvis.

Segmental fixation is employed to maximize rigidity (each level in the curve serves as a point for fixation), and the typical construct includes sublaminar wires at each level, which are attached to 1 (unit rod) or 2 spinal rods. These rods extend down into the posterior ilium to achieve fixation across the lumbosacral joint. A brace is usually not required following this procedure. Although complications are relatively common in comparison with patients with non-neuromuscular curves, the available literature suggests that most patients benefit in terms of function and ease of care. This surgery should ideally be done at centers with significant experience (e.g., trained spine surgeons, anesthesia, intensive care unit).

Compensatory Scoliosis

Leg-length inequality is common and is usually associated with a small compensatory lumbar curvature (Chapter 668). This is 1 cause of false-positive screening examinations. Pelvic tilt toward the short side is associated with a lumbar curve (convexity away from the short leg). There is little evidence to suggest that a small compensatory lumbar curve places the patient at risk of progression or back pain. Because children with leg-length inequality can also have idiopathic or congenital scoliosis, a standing radiograph may be obtained with a block under the foot on the short side (to correct the leg-length discrepancy) to level the pelvis. If the curvature disappears when the limb-length discrepancy is corrected, then a diagnosis of a compensatory curve is made. An alternative is a PA radiograph with the patient seated. In neuromuscular disorders such as polio or cerebral palsy, an adduction or abduction contracture of the hip (fixed infrapelvic contracture) may be compensated for by a lumbar scoliosis to maintain standing or sitting balance. For patients who ambulate, a 10-degree fixed contracture will result in up to 3-cm apparent leg-length discrepancy.

671.4 Kyphosis (Round Back)

The normal sagittal spinal contour is kyphotic in the thoracic spine and lordotic in the lumbar spine. The normal range for thoracic kyphosis is defined as 20-50 degrees of curvature between T3 and T12 using the Cobb technique, and hyperkyphosis is defined by a Cobb angle of >50 degrees. Patients with hyperkyphosis often present with cosmetic concerns and/or back pain, but neurologic dysfunction is rare. The terms flexible or postural are used to describe a curvature that can be corrected voluntarily. If full correction cannot be achieved with active or passive maneuvers, then a fixed or structural component is present. Such a structural hyperkyphosis is much more likely to be associated with an underlying diagnosis such as Scheuermann disease or congenital kyphosis.

A host of conditions may be associated with hyperkyphosis, most often owing to a compromise in the mechanical integrity or growth of the anterior elements of the spine. Examples include injuries (compression or burst fractures), infections (bacterial, tubercular, fungal), metabolic diseases (osteogenesis imperfecta, osteoporosis), neoplastic conditions (eosinophilic granuloma, leukemia), congenital conditions (failure of formation or segmentation), conditions associated with neuromuscular diseases, disorders of collagen (Marfan syndrome), and a number of bone dysplasias (neurofibromatosis, achondroplasia, mucopolysaccharidosis). A progressive kyphosis can also occur following laminectomy or radiation therapy.

Treatment is based on the severity of the deformity, the presence of symptoms (pain, neurologic compromise), and the natural history of the underlying disease process.

Structural Kyphosis

Radiographic Evaluation

Standing PA and lateral radiographs are obtained (Fig. 671-7). The recommended technique for the lateral radiograph involves folding the arms across the chest. A vertical plumb line dropped from C7 should intersect the anterosuperior corner of the sacrum for maintenance of sagittal spinal balance. A coexisting spondylolisthesis is rarely identified on the lateral radiograph. The standing PA radiograph often reveals a mild scoliosis, which is rarely progressive. An MRI is indicated in the presence of neurologic symptoms, and some surgeons routinely obtain an MRI before correcting a kyphosis.

Treatment

Treatment is individualized and depends on the patient’s degree of skeletal maturity, the magnitude of the deformity, and the presence of symptoms. Kyphotic deformities >90 degrees are more likely to be aesthetically unacceptable, symptomatic, and progressive. Deformities in excess of 100 degrees may be associated with pulmonary dysfunction, typically restrictive lung disease.

Skeletally immature patients with mild deformity might benefit from a hyperextension exercise program, but the effects of this strategy on the natural history remain to be documented. Patients with >1 yr of growth remaining and a kyphosis of >50-60 degrees might benefit from a bracing program. A Milwaukee brace (see Fig. 671-3) that extends up to the neck is recommended for curves with an apex above T7, but curves with a lower apex are often be treated by a thoracolumbar orthosis. The brace is recommended for 23 hr/day. On occasion, a serial casting (or stretching) program is instituted to gain flexibility before instituting the brace program. Although the goal of bracing is to prevent progression, a permanent improvement is observed in some patients. When bracing is effective in achieving permanent correction, radiographs show a reconstitution of anterior vertebral height (reversal of wedging). Skeletally mature patients with little or no pain and acceptable cosmesis are not treated.

Typical indications for surgery include progressive deformities >70-80 degrees in patients with persistent back pain despite nonoperative measures and/or dissatisfaction with their cosmetic appearance. The goal is to achieve a spinal arthrodesis while restoring the sagittal profile by correcting the thoracic kyphosis to within the normal range. Overcorrection can also impair sagittal balance, especially in patients with tight hamstrings. Formerly, an anterior release was typically performed before the posterior spinal fusion to improve flexibility, but there has been recent interest in performing an isolated posterior spinal fusion with multiple posterior osteotomies (removal of bone from the posterior elements), and the instrumentation and fusion typically extends from the upper thoracic to the upper lumbar spine.

Congenital Kyphosis

Congenital kyphosis can result from either a failure of formation (more progressive and dangerous) or a failure of segmentation. In an anterior failure of formation (type I), there is an absence of a significant portion of the vertebra, resulting in a progressive kyphotic deformity or toppling over of the spine. This deformity results in neurologic dysfunction, if untreated, from compression of the spinal cord at the apex of the deformity. In type II congenital kyphosis there is an anterior failure of segmentation, with fusion of the involved vertebrae. Progression of kyphosis results from growth of the posterior elements of the spine and is typically slower and more variable than in type I deformities. There is a much lower chance of neurologic dysfunction. Patients must be followed closely, and treatment is required in a significant number of cases. As for congenital scoliosis, abnormalities of other organ systems (cardiac, renal, spinal cord) must be ruled out.

The treatment depends on the type of malformation, the degree of deformity, and whether neurologic symptoms are present. Bracing is ineffective for the primary curvature, but it is occasionally required to control compensatory curves. Surgery is the only effective treatment option for progressive curves or those with a poor natural history (type I), and it typically involves a spinal arthrodesis. Ideally, this can be performed before a significant deformity develops. Because the natural history is so poor for type I kyphoses, spinal fusion is usually performed shortly after the diagnosis is made. Depending on the degree of deformity and/or presence of neurologic dysfunction, excision of the vertebral remnant may be required to decompress the spinal cord and to restore alignment, in addition to a posterior spinal fusion. The vertebral remnant may be excised using an anterior approach before the posterior surgery or through the same posterior approach used for the spinal fusion. Surgical fusion can arrest progression, but deformity correction may be required to achieve a balanced spine. In patients with a mild deformity treated by a posterior spinal fusion, continued growth of the anterior column of the spine can result in some further improvement of the curvature over time. There is a significant risk of neurologic complications associated with surgery for congenital kyphosis, particularly the type I deformities.

671.5 Back Pain in Children

Back pain is a relatively common complaint in children and adolescents, and the differential diagnosis is extensive (Table 671-2). Traditionally, it was thought that the majority of back pain in childhood and adolescence had an organic basis, suggesting the need for an extensive evaluation (including imaging studies) in all patients. Although back pain in infants and toddlers is often associated with underlying pathology, the likelihood of establishing a diagnosis in older children and adolescents is much less, roughly similar to that of the adult population. A definitive diagnosis may be established in 22-36%. The prevalence rate (5-75%) increases with age, approaching that of adults by the age of 18 yr, and most episodes of back pain resolve within 6 wk. Back pain can also be referred from the hip, the sacroiliac joint, or a visceral source. There is some evidence to suggest that back pain is more common with greater weights in backpacks. A thorough history and physical examination, often supplemented by imaging modalities, is required to rule out an underlying pathologic process. The treatment of back pain is tailored to the underlying diagnosis.

Clinical Evaluation

The history begins with the location, character, and duration of symptoms. Pain that is constant, unrelieved by rest, and wakes the patient from sleep is more likely to be secondary to an infection or neoplasm, as are systemic signs (fever) or symptoms (chills, weight loss, malaise). Symptoms of neurologic dysfunction also suggest that an underlying diagnosis is likely. The history must also uncover the presence of any radicular symptoms, gait disturbance, muscle weakness, alterations in sensation, and changes in bowel and/or bladder function.

The physical examination includes a complete musculoskeletal and neurologic assessment, and an abdominal exam should be performed. In appropriate cases, a gynecologic examination may also be helpful. The musculoskeletal examination begins in the standing position, noting any changes in alignment in the frontal or sagittal plane. Range of motion should be assessed in flexion, extension, and lateral bending. Flexion increases compression across the anterior elements of the spine (vertebral bodies and disks), and extension results in compression across the posterior elements (facet joints, pars interarticularis). Pain with flexion suggests an abnormality in the vertebral body or disk. Younger children should be asked to pick up an object off the floor, and pain is often due to diskitis. Pain with hyperextension (ask patient to hold the hyperextended position for 10-20 seconds) might have spondylolysis. Palpation will reveal any areas of tenderness and/or muscle spasm. Leg lengths are also assessed, by palpating the top of the iliac wings while the patient is standing. Because spinal pain may be referred, an abdominal examination should be performed, and in girls, a gynecologic evaluation may be necessary. The sacroiliac joint should be stressed by compression across the iliac wings or by forced external rotation with the hip and knee flexed to 90 degrees. The hamstring muscles should always be evaluated, because contracture is commonly associated with diagnoses such as Scheurmann disease, spondylolysis or spondylolisthesis, a herniated disk (or slipped vertebral apophysis), or other pathologies.

The neurologic examination includes manual muscle testing and an evaluation of sensation and proprioception. The superficial abdominal reflex should be tested by gently stroking the skin on each of the 4 quadrants surrounding the umbilicus. Normally, the umbilicus moves toward the area stimulated, and a normal examination is defined by a symmetric response (present or absent on both sides). Asymmetry suggests the presence of a subtle abnormality of spinal cord function, most commonly syringomyelia. The straight leg raise test is performed by raising up one leg with the knee extended. This test evaluates tension on the lower spinal nerve roots, and radicular symptoms (pain or tingling below the knee) will be reproduced. Possible causes of radiculopathy include a herniated disk, slipped vertebral apophysis, spondylolisthesis, tethered cord, and other causes. To further confirm the abnormal compression or stretch on the nerve root, the limb may be lowered to a position in which the symptoms are no longer present, and the foot is then dorsiflexed. Reproduction of the findings or symptoms with dorsiflexion of the foot further suggests the presence of nerve root compression or tension.

Bibliography

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Bockowski L, Sobaniec W, Kulak W, et al. Low back pain in school-age children: risk factors, clinical features and diagnostic management. Adv Med Sci. 2007;52(Suppl 1):221-223.

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Feldman DS, Straight JJ, Badra MI, et al. Evaluation of an algorithmic approach to pediatric back pain. J Pediatr Ortho. 2006;26:353-357.

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Watson KD, Papageorgiou AC, Jones GT, et al. Low back pain in schoolchildren: the role of the mechanical and psychosocial factors. Arch Dis Child. 2003;88:12-17.

671.6 Spondylolysis and Spondylolisthesis

Spondylolysis is an acquired condition that involves a unilateral or bilateral defect in the pars interarticularis, the region of bone between the superior and inferior articular facets. Spondylolysis is identified in 4-6% of the adult population and is thought to result from repetitive hyperextension stresses, presumably resulting in mechanical impaction of the inferior articular facet of the superior vertebra against the pars interarticularis of the inferior vertebra. Repetitive tensile loading is also postulated in some cases, and abnormalities of the sacral growth plate have been implicated in some cases as well. The process can begin with a stress reaction, which can then lead to a stress fracture, and ultimately to an established pseudarthrosis (nonunion or “false joint”) at the pars interarticularis. Spondylolysis is most common in athletes with activities involving repetitive spinal hyperextension, especially gymnasts, football players (especially interior linemen), weight lifters, and wrestlers. Persons with excessive lumbar lordosis may be at higher risk, and a genetic component has been suggested. The lesion is most common at L5, but it may also be identified at higher levels in the lumbar spine, and it rarely occurs at more than one level. The natural history is variable; many patients are asymptomatic, but a subset experiences mechanical low back pain that can limit activities and require treatment. Approximately 15-25% of patients develop a spondylolisthesis.

Spondylolisthesis involves slippage of 1 vertebra on another and is most common at L5 (85-95%). In children and adolescents, the most common types are dysplastic (congenital) and isthmic (results from a stress fracture). In a dysplastic spondylolisthesis, the posterior elements of the spine remain intact but are elongated. Progression of spondylolisthesis has been associated with a higher degree of slippage (>50%), lumbosacral kyphosis (slip angle > 40 degrees), and dome-shaped sacrum. It is more common in female and in younger patients.

Clinical Manifestations

Symptomatic patients with spondylolysis or spondylolisthesis usually present with mechanical low back pain that can radiate to the buttocks and thigh but rarely below the knee. The pain is exacerbated by spinal hyperextension, which exerts compression on the posterior elements. A useful provocative test, with the patient standing, involves placing the spine in hyperextension and holding the position for up to 10-20 seconds. This compresses the posterior elements and might reproduce the symptoms. In contrast, pain emanating from disk space pathology is exacerbated by spinal flexion. Physical examination might also reveal tenderness over the spinous process of the involved vertebra. Hamstring spasm, with or without contracture, is commonly observed.

The physical findings may be more pronounced in patients with spondylolisthesis. The buttocks appear flattened (sacrum is more vertically inclined, lumbosacral kyphosis), and the abdomen might appear more protuberant (hyperlordosis above the lumbosacral kyphosis). There is often a palpable step off between the spinous processes at the involved levels, especially with a high-grade slip. Hamstring spasm or contracture is usually more pronounced than in spondylolysis. Gait disturbance is also observed, typically characterized by mild crouching, a short stride length, and an incomplete swing phase. A careful neurologic examination is required. In addition to back pain, neurologic symptoms (radiculopathy or bowel or bladder dysfunction) can result from compression of the cauda equina or nerve roots. Radicular symptoms or findings are uncommon except in high-grade spondylolisthesis, when there may be excessive tension (or mechanical compression) on the lower lumbar nerve roots. In contrast to lumbar disk herniations, which most commonly affect the lower root (L4-L5 disk herniation compresses the L5 nerve root), spondylolisthesis of L5 on S1 affects the L5 nerve root.

Radiographic Evaluation

The initial evaluation of the lumbar region should include high-quality anteroposterior, lateral, and oblique radiographs. The pars is best visualized on the oblique radiographs, and a pars defect has been termed the Scotty dog sign. Standing PA and lateral radiographs are obtained if findings suggestive of scoliosis or hyperkyphosis are also present (Figs. 671-8 and 671-9). In patients with normal plain films, a bone scan with SPECT images can help to diagnose a spondylolysis during the early stages (stress reaction), before a fracture or an established pseudarthrosis develops. A CT scan with thin cuts can establish the presence of a pars defect or a pseudarthrosis. If the bone scan shows no increased uptake in the region, and a CT scan demonstrates a pars defect, then the potential for healing is felt to be limited. Although MRI is most commonly indicated in the presence of signs or symptoms of cauda equina or nerve root involvement, it has been used more and more during the diagnostic phase.

image

Figure 671-8 A, Normal spine at 9 mo of age. B, Spondylolysis in the L4 vertebra at 10 yr of age.

(From Silverman FN, Kuhn JP: Essentials of Caffrey’s pediatric x-ray diagnosis, Chicago, 1990, Year Book Medical Publishers, p 94.)

image

Figure 671-9 Defect in the pars interarticularis (arrow) of the neural arch of L5 (spondylolysis) that has permitted the body of L5 to slip forward (spondylolisthesis) on the body of S1.

(From Silverman FN, Kuhn JP: Essentials of Caffrey’s pediatric x-ray diagnosis, Chicago, 1990, Year Book Medical Publishers, p 95.)

Spondylolisthesis is graded according to the degree of translation of the superior vertebra as follows: grade 1, <25%; grade 2, 25-50%; grade 3, 50-75%; grade 4, 75-100%; and grade 5, complete displacement or spondyloptosis. The degree of rotation of the upper vertebra on the lower (kyphosis) is also measured as the angle in between a line drawn along the posterior margin of the sacrum and a line drawn along the superior end plate of the L5 vertebra (slip angle). In patients with spondylolisthesis, flexion and extension films are occasionally performed to identify instability (excessive translation through this range of motion). Because progressive slippage can occur in a subset of skeletally immature patients, a standing lateral radiograph of the lumbar spine should be considered every 6-12 mo.

Treatment

Asymptomatic patients with spondylolysis require no active treatment, but those with pain are treated with rest and/or modification of activity, physical therapy (focusing on hamstring stretching and strengthening of the abdominal musculature), and non-narcotic analgesics. In patients with a stress reaction or early stress fracture without an established pseudarthrosis, healing may be achieved with nonoperative measures. Unilateral defects are more likely to heal when compared with bilateral defects, and the presence of high signal in the adjacent pedicle on MRI also implies a better chance of healing. A modified lumbosacral orthosis, which reduces lumbar lordosis (15 degrees of flexion of the lumbar spine) and immobilizes the spine, is typically recommended for 3-4 mo full time. For patients with an established pseudarthrosis, the goal is relief of symptoms rather than union. Overall, nonoperative measures are successful in the majority of patients, and a successful clinical outcome does not depend on healing of the lesion.

Surgery is offered when symptoms persist despite an adequate trial of nonoperative therapy. For spondylolysis, surgical options include repair of the pars defect versus spinal fusion. If the spondylolysis is at L5, then a posterior spinal fusion from L5 to S1 is most commonly performed. For the uncommon cases in which the defect is at L4 or at higher levels, techniques for repairing the defect should be considered. If successful, these procedures will avoid the need for surgical fusion. Some surgeons use an MRI to evaluate the disk space at that level and select a fusion rather than a pars repair if there are degenerative changes in the disk.

Recommendations for managing spondylolisthesis depend on the age of the patient, the presence of symptoms (pain and/or neurologic), the degree of deformity, and to a lesser extent cosmetic concerns. For low-grade lesions (<50% slippage) with chronic symptoms despite nonoperative treatment, a posterior spinal fusion alone, with or without instrumentation, may be successful. For skeletally immature patients with >50% slippage, with or without symptoms, surgery is offered given the risk of progression. The surgical approach for higher-grade slips varies among surgeons and institutions. The main principle is to stabilize the unstable segment of the spine through spinal fusion, either a posterior or an anterior and posterior spinal fusion with spinal instrumentation.

Whether or not to reduce the spondylolisthesis at the time of surgery remains a subject of controversy. A reduction may be achieved through gravity or intraoperative positioning or through direct realignment using the spinal implants. Although neurologic symptoms can resolve with stabilization, a decompression of the neural elements is commonly performed as a component of the stabilization procedure for high-grade spondylolisthesis.

671.7 Disk Space Infection

Both diskitis and vertebral osteomyelitis may be considered as age-dependent variations of infectious spondylitis. Diskitis is generally seen in children <5 yr of age, and vertebral osteomyelitis occurs in older children and adolescents. This spectrum may be explained on the basis of anatomy; the vertebral column in infants and younger children has vascular channels that communicate between the vertebral end plate and the vascular disk space, allowing organisms to seed the disk space (Table 671-3). Once these channels have closed, the infection remains in the vertebra.

Table 671-3 SPECTRUM OF NONTUBERCULOUS INFECTION OF THE SPINE

SIGNS, SYMPTOMS, AND DEMOGRAPHICS DISKITIS VERTEBRAL OSTEOMYELITIS
Most common age Younger than 7 yr
Peak at 3 yr
Older than 8 yr
Symptoms Limp, back pain
Refusal to walk
Same as for diskitis
Location of lesion Lumbar Anywhere along spine
Febrile Less likely (28%) More likely (79%)
Laboratory values (complete blood Count, sedimentation rate) Nonspecific elevation Nonspecific elevation
Plain radiograph Early: normal
>20 days: disk space abnormal
Early: normal
7-20 days: disk space and vertebrae abnormal
Magnetic resonance imaging Localizes lesion Localizes lesion
Defined soft tissue involvement
Blood culture Often negative Often positive
Antibiotic therapy Controversial Yes

From Slovis TR, editor: Caffey’s pediatric diagnostic imaging, ed 11, vol 1, Philadelphia, 2008, Elsevier.

The available evidence suggests that diskitis is a low-grade bacterial infection rather than an inflammatory process. Cultures of either the blood or disk space are positive in only 50-60% of patients, and Staphylococcus aureus (Chapter 174) is the most common organism isolated. Cultures are more likely to be positive if the symptoms have been present for <6 wk. Other organisms include Kingella kingae (Chapter 676), group A streptococcus (Chapter 176), and Escherichia coli (Chapter 192).

The differential diagnosis includes infectious, inflammatory, neoplastic, and developmental conditions. Granulomatous infections, such as brucellosis and tuberculosis, and fungal infections typically involve the anterior elements of the spine and must always be considered under certain circumstances (immunocompromised host, history of travel to certain regions, immigrants from selected regions). Neoplastic diseases involving the anterior elements include eosinophilic granuloma, leukemia, and lymphoma. Inflammatory conditions such as juvenile idiopathic arthritis can also manifest with symptoms similar to diskitis. Back pain can also be referred from another source. Other conditions in the differential diagnosis include intra-abdominal conditions (appendicitis, pyelonephritis), septic arthritis of the sacroiliac joint, psoas abscess, or hip pathology (septic arthritis or other).

Clinical Manifestations

A high index of suspicion is required to establish the diagnosis of diskitis, especially in younger patients. The differential includes vertebral osteomyelitis (see Table 671-3). In addition to back pain and/or fever, patients can experience malaise, and toddlers can develop a limp or refuse to walk or sit. Spinal motion is voluntarily reduced to alleviate pain, and paraspinal muscle spasm is common. Flexion of the spine compresses the anterior elements of the spine and should increase any discomfort. This may be tested by asking the child to pick up an object from the ground. There may a loss of the normal lumbar lordosis. Neurologic manifestations are rare. Patients may be afebrile, and although a complete blood count might remain normal, the erythrocyte sedimentation rate and the C-reactive protein are usually elevated. Older children might have fever and abdominal pain.

671.8 Intervertebral Disk Herniation and Slipped Vertebral Apophysis

Intervertebral disk herniation and slipped vertebral apophysis are extremely rare in children and uncommon in adolescents. The symptoms and physical findings are quite similar to those in adults. Although the etiology remains unknown, predisposing factors for both of these can include disk degeneration, congenital malformation (altered regional biomechanics), genetics, and environmental factors (trauma or repetitive stresses). Herniated disk is a term that reflects a spectrum of pathology from simple protrusion of the disk material with an intact annulus fibrosis to the herniation of a free fragment of disk material into the spinal canal. Both are space-occupying lesions, and symptoms are due to either direct mechanical compression of nerve roots (or cauda equina) or an inflammatory response in proximity to neural elements. Ossification of the ring apophysis begins around 6 years of age, and the apophysis fuses with the vertebral body at approximately 17 years of age. Slipped vertebral apophysis involves protrusion of a portion of the ring apophysis with or without an attached segment of bone. The symptoms are similar to that of a herniated disk; in one study the two entities coexisted in 28% of adolescent disk herniations.

Treatment

The initial treatment is nonoperative in most patients and focuses on rest, activity modification, analgesics, and physical therapy. An orthosis can provide additional symptomatic relief. Complete bed rest is not recommended. The role of epidural steroids remains to be determined. Surgical treatment should be considered when nonoperative measures have failed or when a profound neurologic deficit or cauda equina syndrome is present either initially or as the clinical course evolves.

Unfortunately, children and adolescents respond less favorably to nonoperative therapy compared with adults, and a significant percentage require surgical intervention. The surgical technique involves laminotomy and subtotal disk excision to decompress the neural elements. In the case of a slipped vertebral apophysis, a similar approach is employed for decompression of the neural elements, but there is some controversy about whether or not to routinely remove the apophyseal fragment. Some surgeons remove the fragment when there are neurologic symptoms; one report suggested that an intraoperative assessment of the mobility of apophyseal fragments is helpful, and the authors only removed loose fragments. A bilateral laminotomy may be required in these cases to address the pathology.

Although the initial results are excellent in the majority of patients, the literature suggests that up to a third of patients have recurrent symptoms of back or leg pain at longer term follow-up. The reoperation rate is in the range of 15%, similar to that of the adult population. A spinal fusion may be required when clinical instability is present.

671.9 Tumors

David A. Spiegel and John P. Dormans

Back pain may be the most common presenting complaint in children who have a tumor involving the vertebral column or the spinal cord. Other associated symptoms can include weakness of the lower extremities, scoliosis, and loss of bowel or bladder function. The majority of tumors are benign (Chapter 495). Lesions that may be observed in the anterior elements of the spine include aneurysmal bone cyst, eosinophilic granuloma, leukemia, and lymphoma; common tumors involving the posterior elements include osteoid osteoma and osteoblastoma. Malignant tumors involving the vertebral column may be osseous (osteosarcoma or Ewing sarcoma) or rarely are due to metastatic disease. Lesions in the soft tissues surrounding the spine are most commonly neurogenic, involving the spinal cord and sympathetic nerves (ganglioneuroma, ganglioneuroblastoma, neuroblastoma). In addition to high-quality plain radiographs, modalities including a bone scan (localization, look for other lesions), MRI (soft-tissue extension, neurologic compression) and CT (excellent bony detail) are performed in most cases before making a treatment plan. A biopsy is usually required to establish the diagnosis, and the treatment of tumors of the spinal column can require a multidisciplinary approach and should ideally be done in centers with experience in managing these lesions.