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A 14-year-old boy with scoliosis and rib pain
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A 14-year-old boy presented to the orthopedic clinic for assessment of scoliosis. His pediatrician had obtained a recent chest radiograph to further evaluate a diagnosis of costochondritis, and a mild scoliosis was incidentally noted. The patient denied having back pain, and had not previously noticed any prominence or curvature.
On thorough interview, his only complaint was a 2-year history of intermittent chest pain which he isolated along the inferior border of his left anterior ribs. His pain was aggravated by activities such as football, basketball and wrestling, and occasionally woke him at night. Physical therapy and anti-inflammatories had been of moderate benefit, but his symptoms were becoming more persistent.
Examination and imaging
Clinical examination revealed a well appearing young man with 5/5 strength in all lower and upper extremity muscle groups. Sensation was intact throughout the C5-L1 and L2-S1 distributions bilaterally. Reflexes were 1+ and symmetric in all extremities. Abdominal reflexes were symmetric in all quadrants, and there was one beat of clonus bilaterally. On forward bending, there was a mild right thoracic prominence which was flexible and painless with side-bending and hyperextension. There was no tenderness along the ribcage or the costochondral junction. The patient’s symptoms were irreproducible on exam.
Figure 1. The patient’s preoperative PA scoliosis radiograph (a) with enhanced PA image centered at T7-T8 (b) are shown.
Images: Warth LC and Weinstein SL
Posteroanterior (PA) scoliosis film demonstrated a mild 15° right thoracic scoliosis (Figures 1a and 1b), and on close inspection there was as subtle lucency with no clear left-sided pedicle at the T8 level, a so-called ‘winking owl’ sign. This prompted further evaluation with a bone scan (Figure 2), which also demonstrated isolated uptake at this level and subsequently a limited CT scan (Figures 3a and 3b).
Figure 2. Whole body technetium bone scan demonstrates radiotracer uptake in the left pedicle of T8.
Figure 3. Preoperative axial (a) and sagittal (b) CT cuts demonstrate a lytic lesion at T8.
What is your diagnosis?
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Scoliosis secondary to T8 osteoblastoma with associated thoracic radiculopathy
Adolescent idiopathic scoliosis (AIS) is common, with an incidence of 1% to 3% for curves between 10 ° and 20°, and 0.3% for curves greater than 30°. For smaller curves, there is a 1:1 male to female ratio, and right thoracic (thoracic scoliosis) curves are most common. While scoliosis can be associated with intermittent and self-limiting musculoskeletal back pain, red flag signs include: persistent pain or long-standing pain, night pain, atypical curve pattern (left thoracic scoliosis, excessive/apical kyphosis), rapid progression, neurologic symptoms or asymmetric reflexes.
Lucian C. Warth
Thorough initial exam is paramount and should include full evaluation of strength, sensation and reflexes, and skin defects, hair tufts or café au lait spots. Atypical history or physical should prompt the physician to consider a more thorough evaluation. A full work-up could involve advanced imaging including a bone scan and/or CT, as well as lab work (complete blood count with differential, erythrocyte sedimentation rate, c-reactive protein, chem-7, antistreptolysin-O, antinuclear antibodies, etc.) If neurologic symptoms or abnormal physical exam findings are elicited, MRI should be considered to evaluate for Chiari malformation, syrinx, tethered cord or other intraspinal pathology. MRI should include the posterior fossa through the lumbar spine.
Stuart L. Weinstein
In this case, initial exam and presence of mild radiographic scoliosis without atypical features were not ominous and were most consistent with AIS; however a history of long-standing and persistent symptoms and night pain prompted closer radiographic scrutiny of the thoracic levels, which correlated with the patient’s clinical pain. A subtle lucency was identified on plain radiograph (Figures 1a and 1b), which subsequently prompted further work-up to evaluate for underlying etiologies. Bone scan (Figure 2) and limited CT (Figures 3a and 3b) (to minimize radiation exposure) demonstrated a large lytic lesion in the left T8 pedicle most consistent with osteoblastoma based on size, location and appearance.
Osteoid osteoma and osteoblastoma are both benign osteogenic neoplasms. They are histologically similar, and most commonly present in the second decade of life. Osteoblastomas are characteristically larger, usually greater than 2 cm in size. Osteoblastoma accounts for approximately 1% of primary bone tumors, and is most frequently located in the posterior elements of the axial spine. Plain radiograph is seldom sensitive enough to establish a diagnosis. Marked uptake is seen on bone scan which is sensitive, but not specific, to the diagnosis. CT can more firmly establish the diagnosis and define size, expansion, cortical destruction, as well as direct treatment. MRI may beneficial mainly if there is concern for extensive erosion or infiltration into the canal, or specific compromise of neural elements.
Due to size and tendency to present in the vertebral column, osteoblastoma may present with neurologic symptoms, numbness, tingling or radicular symptoms. Scoliosis can be secondary to muscle-associated muscle spasm. Unlike osteoid osteoma, pain is usually not worse at night and NSAIDs provide less effective relief. Osteoblastoma is often locally aggressive, and surgical treatment is often preferred to prevent continue bone destruction.
Figure 4. The 2-year postoperative PA (a) and lateral (b) radiographs demonstrate T7-T9 posterior spinal fusion with interval correction of scoliosis.
Surgical intervention should be considered if pain cannot be adequately controlled, if the lesion is large or if the lesion is increasing in size. While percutaneous ablation has been described and is well accepted for osteoid osteoma of the extremities, this is a poor choice for larger osteoblastomas and osteoid osteomas near neural elements, as in this case. Surgery can include intralesional curettage, which is sufficient in most cases, plus or minus adjunctive modalities such as cryotherapy or phenol, to enhance margins and minimize microscopic tumor burden which is a source of recurrence. Care must be taken when considering use of these adjuncts around neural elements. En bloc resection is an excellent option, and is often employed for recurrent lesions or when the location and size of the primary lesion allows. Depending on the size and location of the lesion and subsequent bony resection, bone cement, lesional grafting or instrumented fusion may be necessary to ensure stability.
Figure 5. The 2-year postoperative axial (a) and sagittal (b) CT cuts demonstrate the resected lamina, pedicle, and rib head at T8 with evidence of bony fusion, local remodeling and no disease recurrence.
Treatment, follow-up care
In this case, after standard posterior spinal exposure pedicle screws were implanted at T7 and T9 bilaterally, and these segments were then stabilized on the right prior to proceeding with a left-sided posterolateral costotransversectomy to adequately visualize the lateral aspect of the lesion including the T8 pedicle and vertebral body. An en bloc excision of the left lamina, rib head, transverse process and pedicle of T8 was performed. Subsequent instrumented posterior spinal fusion from T7-T9 was then implemented to stabilize the defect.
At 6-week follow-up, the patient had complete resolution of rib/chest wall pain, with minor discomfort posteriorly in the area of the rib head resection. At 6 months follow-up, the patient was asymptomatic and was released to moderate aerobic activity and weight lifting with gradual self-directed return to unrestricted activity. In addition to plain radiographs, at 3 months, 6 months, 12 months, and 24 months limited CT scans were obtained to monitor for recurrence, which were negative for disease and demonstrated excellent bony fusion (Figures 4a and 4b and 5a and 5b).
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Disclosures: Warth and Weinstein have no relevant financial disclosures.