In the system proposed by Banta and Hamada, kyphosis associated with myelomeningocele can be classified into three types: flexible paralytic kyphosis, kyphoscoliosis, and congenital rigid kyphosis4. Those authors reported that patients with a flexible paralytic kyphosis had gentle C-shaped curves that progressed at a rate of 3° per year. Patients with kyphosis associated with scoliosis, or kyphoscoliosis, had more rapid progression, at a rate of 6.8° per year. Patients with the last type, congenital rigid kyphosis, had progression at a rate of 8.3° per year.
Patients with a gibbus deformity usually present at birth with a characteristic kyphotic deformity associated with other problems. Because the body center of gravity is displaced forward, patients tend to sit on the posterior aspect of the sacrum, with the pelvis being horizontal to the sitting surface, although our patient did not have a horizontal sacrum (Figs. 1-A and 1-B)1-3. Two-handed activities become a challenge as the hands are needed for support. Besides the sitting imbalance, the severe gibbus deformity imposes difficulty with lying supine. Pressure and tension on the insensate skin over the gibbus deformity can lead to skin breakdown and severe ulceration, and recurrent infections may develop16,27. Additional flexion of the trunk causes crowding of the abdominal contents, and abdominal pressure against the diaphragm increases. Respiratory problems may occur because of incompetent inspiratory muscles3,6,28. Drainage of urine from the ureters may be affected by the flexed position and may impair urological management such as self-catheterization1,3,10,29.
This clinical problem often has been associated with a high rate of complications and an undesirable long-term clinical outcome. Many complications have been reported, including instrument failure and curve progression3,8,10,12,14,16,17,30,31, infection8,10,19,21,31,32, delayed wound-healing7,8,10,13,21,31, large blood loss5,10,16,17,21, acute hydrocephalus necessitating shunt revision surgery17,19,21, cerebrospinal fluid leak8,19, acute respiratory distress syndrome31, meningitis31, urinary tract infection10,31,32, death10,12,14,17,30, and pneumonia16,31. The prolonged use of a body cast and brace after surgery has been associated with a high rate of pathological femoral fractures7,16.
To our knowledge, the use of growth-sparing instrumentation for the treatment of congenital gibbus deformity in children with myelomeningocele has not been described previously. The ability to use the VEPTR device offers some distinct advantages over other techniques. These advantages include the ability to correct the deformity without fusion, allowing for continued growth of the spine; attachment of the fixation away from the gibbus deformity; the low profile of the instrumentation; and the simplicity of the distraction procedures.
A limitation of the present report is the relatively short duration of follow-up for a skeletally immature patient. The patient discussed here had a successful outcome in the early follow-up period. As she continues to grow, further study is necessary. In addition, the long-term effects of growing devices in an otherwise healthy thorax are unknown, although there is no evidence to suggest that the use of such devices would limit growth or inhibit lung function.
The present report demonstrates the relative feasibility of using the VEPTR device for the treatment of severe gibbus deformity in patients with myelomeningocele. Our patient exhibited excellent correction of the kyphotic deformity, experienced adequate recovery time, and had minimal complications.