Comparison of Complications Among Growing Spinal Implants

Retrospective review. To evaluate the complication rate of various types of growing spinal implants. Previous studies report a complication rate of 0.38 to 1.19 per patient in growing spine surgery, but this may be an underestimate. Medical records of 36 children with early-onset spinal deformity treated with various types of growing implants by a single surgeon were evaluated for complications. Patients with primary chest wall deformities were excluded. Complications were defined as any neurologic injuries, and any unplanned surgeries for implant failure or infection. Patients were separated into 3 groups: (A) standard dual growing rods, (B) hybrid growing rods with rib anchors proximally and spine anchors distally, and (C) VEPTR (vertical expandable prosthetic titanium rib). Statistical analyses were performed to compare the complication rate among the 3 groups and to evaluate the effect of Cobb angle, kyphosis, age, and body mass index on the complication rate. Mean age at initial implantation was 4.8 years; mean follow-up was 51 months (24-117 months). A total of 72 unplanned surgeries occurred in 26 out of 36 patients (72%), including 18 revisions for rod breakage, 31 revisions for migrated anchors, and 18 irrigations and debridements for infection. Two children (5.6%) developed a neurologic deficit that required implant removal. Group A had 23 complications in 10 patients, with a complication rate of 2.3 per patient; group B had 6 complications in 7 patients, with a rate of 0.86 per patient; and group C had 45 complications in 19 patients, with a rate of 2.37 per patient. There was no significant difference between the 3 groups in terms of preoperative Cobb angle, kyphosis, age, and body mass index; these factors did not seem to influence the complication rate. To our knowledge, this is the first study directly comparing the complication rates of various types of growing spine implants. The complication rate in growing spine surgery is uniformly high but varies by implant type, with a trend toward fewer complications in hybrid constructs.