Pediatric Spinal Deformity

Eric A. Loveless, M.D.
Eric A. Loveless, M.D. is a Pediatric Orthopaedic Surgeon at Nemours Children's Clinic.

Spinal deformity in children is relatively common and frequently evaluated by the primary care physician and referred for treatment to pediatric specialists. A clear understanding of the presentation, initial examination, differential diagnosis and potential treatments for these disorders is essential for appropriate care of these patients in the primary care setting.

Infants through adolescents may present to the physician with no symptoms or complaints by the patient or family during a routine examination. The keen eye of the examiner may be the most important tool in the initial diagnosis. Rarely the child appears with significant spinal deformity which alters the physical appearance or complaints of pain. Ideally, early diagnosis of the problem is the goal that may limit the eventual treatment of the child with hopes of preventing more aggressive and risky surgical procedures.

Understanding the basic anatomy and stance of the child is important. During the evaluation, observation of the child from the back, side and front is necessary to pick up subtle deformities. A checklist of observations may be helpful during the exam. All children must be examined with modesty but limiting clothing to underwear is necessary. First one must observe the child from the back noting the head alignment to the gluteal crease, the shoulders should be level, scapula symmetrical, flanks should be symmetrical and pelvis level. (Figure 1) On forward bend with the fingers touching the knees, the ribs should be level and when touching the toes the lower back should be without rotation. The only true pathognomonic sign of scoliosis is the presence of a curve on forward bending, termed a positive Adam's forward bending test. (Figure 2) This can be documented by simple observation or a scoliometer. Looking at the child from the side normal kyphosis and lordosis should be present with no exaggeration noted on forward bend. (Figures 3 and 4) A full neurological exam should be normal, including motor, sensory and reflex examination. Skin examination may represent stigmata of underlying causes of scoliosis (cafe au lait spots, hairy patches or skin dimples overlying the spine). Radiographs rarely should be ordered on the initial evaluation, and if ordered should be performed on a long scoliosis film, standing preferably. Multiple exposures by the smaller films usually do not allow full evaluation of the spine and requires more radiation to the child.

Screening tests historically have shown the presence of lateral curvature as high as 5% in school age children.¹ School screening examination, though controversial, continues to be performed in Jacksonville. Most important however would be the routine spinal evaluation during normal physical examination (by a simple Adam's forward bending exam) from the age of 7 until puberty.

A number of terms are essential for the proper understanding of spinal deformities. Scoliosis refers to a lateral deviation of the spine in the coronal plane. By anatomic necessity this lateral deviation is associated with rotation and in the thoracic spine a prominence of the ribs occurs, when in the lumbar spine a prominence of the flank may be noted. Scoliosis of greater than 10º on radiograph is considered abnormal. Kyphosis (roundback) commonly is referred to the excessive curvature in the thoracic spine from the lateral view. One must differentiate between the smooth curve and the sharp short curves that may have pathologic etiologies.

Apparent, nonstructural, flexible or "functional" scoliosis may be seen with poor posture, limb length inequality, or flexible contracture of the hip or knee. The curve usually disappears when the child is sitting. Other causes may be paraspinal muscle spasm following injury, pyelonephritis, appendicitis, or pneumonia. The deformity seen with functional scoliosis usually allows correction of the deformity by correcting the underlying problem.

Except in curvatures resulting from inflammatory causes, back pain is rarely associated with scoliosis. Back pain usually is an indication for a more intensive workup for evident scoliosis.

Structural scoliosis is characterized by a fixed curve. The most common cause of structural scoliosis is idiopathic scoliosis, followed by congenital deformities (spinal, scapula, pelvic and extremity), and less common conditions that may result in scoliosis including neuromuscular disorders, trauma, post surgical changes and metabolic disorders. Congenital scoliosis may be associated with other congenital anomalies that differentiate simultaneously such as cardiac and renal anomalies.

Idiopathic scoliosis may present at various age groups — infantile 03 years, juvenile 310 years, adolescent >10 years. Adolescent scoliosis is the most common form of spinal deformity evaluated and referred by the primary care physician, and therefore will be discussed more fully. The majority of the cases have their onset immediately prior to puberty. Adolescent idiopathic scoliosis of 10º has a prevalence of 23 %, with curve sizes of greater than 20º far less common. A familial predisposition may be documented (prevalence reported as high as 20% with a positive family history) however inheritance of this appears to be multifactorial. Females are more likely to have progression of their curvature (58 times higher in girls compared to boys).

Research in etiology continues with basic science studies. The most exciting avenue of research is the effect of melatonin on scoliosis. Chickens and bipedal rats have had their pineal gland removed with a dramatic increase in incidence of scoliosis. Upon administration of melatonin the development of the scoliosis appears to be significantly decreased. Application of research on humans² in this area has recently started, though in the infancy this may be a promising treatment modality, which may limit progression of curves and surgical treatment.

Postural roundback and Scheuermann's kyphosis congenital kyphosis would be the most common causes for spinal deformity on the lateral stance. Postural kyphosis is flexible and gradual and usually can be corrected voluntarily by the patient. Scheuermann's kyphosis and congenital kyphosis are more rigid and structural and usually represent a shorter sharper curve on forward bend.

Spondylolesthesis is a condition characterized by the translation or forward displacement of one vertebral body over another, most commonly seen at the lumbar sacral junction. Presentation may be a normal exam (noted incidentally on lateral radiograph of the lumbar spine) or pain associated with inflammation of nerve roots and hamstring contracture. Alarming degrees of translation may be present with minimal symptoms. These patients may exhibit a waddling gait, transverse abdominal crease, flattened buttocks and flexion deformities of the hips and knees. The incidence of spondylolesthesis is approximately 25% in the adolescent population. The onset is rarely before age 5 and peak presentation is by 20 years of age. Increased incidence has been noted in gymnasts, football lineman and weight lifters.

Idiopathic scoliosis treatment varies with the skeletal age and curvature size of the patient. Skeletally immature patients whose curve is greater than 1020º should have close followup with physical exams until skeletal maturity. Children with curves in this range may only require observation as the sole treatment. Curves between 2029º may not require treatment, however if progression of the curve greater than 5º is noted, bracing may be instituted. If a curve is identified initially between 30-40º brace treatment should begin immediately.

The efficacy of bracing for idiopathic scoliosis has been called into question, and now with several types of bracing application of braces is becoming more complex.³ Currently the author recommends a nighttime bending brace for curves less than 3035º as it has been shown to be as effective as full time underarm braces, with compliance more likely in hot humid climates. Other braces have been recommended for specific types of curves.

Surgical treatment is strongly indicated in curves greater than 50º with consideration of surgery between 4050º. Although the goal has not changed (maximize correction of the deformity, and stabilization of the curve by bony fusion), techniques have changed over the years. Various generations of hook, screw and rod systems have evolved which allows improved correction and less postoperative immobilization. More recently the advent of thoracoscopic approaches to the thoracic spine have allowed small incisions in the chest to either loosen the anterior spine for improved correction or stopping spinal growth. Placement of rods and screws through these small incisions may be an option for isolated thoracic curves, which may eliminate the long posterior incisions.

Treatment of congenital and neuromuscular curves is less frequent and more complex and therefore will not be discussed extensively. Bracing appears to be far less useful in these children and surgical options may be discussed in the appropriate candidates.

Extension exercises, reassurance and observation treat postural kyphosis. Unfortunately compliance in the adolescent who has no complaints of pain is limited. Scheuermann's kyphosis natural history appears to be modified somewhat by treatment.⁴ Bracing kyphotic curves greater than 50º may allow some improvement of cosmesis and pain.⁵ Surgical treatment continues to be controversial and should be limited to the extremely large curves (>70º) and those with back pain not relieved by conservative methods.

The goal of treatment for patients with spondylolysis is reduction of symptoms and prevention of spondylolesthesis. Conservative measures include modification of activity, antiinflammatory medication, and bracing. Indications for surgery include pain unrelieved by conservative methods, progression of the deformity, or neurological findings. Surgical treatment for spondylolysis and spondylolesthesis is rare.

Spinal deformity in the pediatric population is uncommon and may have many causes. The most common of all deformities evaluated in the primary care setting is scoliosis, which can be treated by observation, bracing or surgery as indicated by the skeletal age and size of the curve. Almost all spinal deformities in children can be treated with proper evaluation and planning. The physiologic and psychological sequelae of these deformities should be considered and be minimized by the appropriate treatment.

REFERENCES

1. Bunnell W. The natural history of idiopathic scoliosis. Clinical Orthopedics. 1988; 229: 2025.
2. Hillibrand A. The role of melatonin in the pathogenesis of adolescent idiopathic scolisosis. Spine. 1996; 21(10):11401146.
3. Nachemson A. Effectiveness of treatment with a brace in girls who have idiopathic scoliosis. J Bone Joint Surg Am. 1995; 77: 815822.
4. Murray P. The natural history and longterm followup of Scheuermann's kyphosis. J Bone Joint Surg Am. 1993; 75: 236248.
5. Bradford D. Scheuermann's kyphosis and roundback deformity: Results of Milwaukee brace treatment. J Bone Joint Surg Am. 1974; 56:74058.