Off-Label Use of Spinal Screws in Children

Back in the 1960s, surgeons started to use a new type of fixation device to help hold the spine together during a fusion procedure: the pedicle screw. At first, this screw through the bone was only used in the lumbar spine (low back). But over time, the use of pedicle screws expanded — first to the thoracic spine in adults and then to the spine of adolescents.

Currently, the use of pedicle screws in the 13 to 18 year old patient for spinal stabilization has been approved by the Food and Drug Administration (FDA). Its use in younger children has not yet been approved because of a lack of evidence for the safety of this device in this age younger group.

However, pedicle screws are used in children ages one to 12 with scoliosis (spinal curvature) or other spinal deformities requiring spinal fusion. This use is considered off-label because of the lack of FDA approval at this time.

The pedicle is a column of the vertebra between the main body and the back half of the spinal bones. Placement of a screw through this portion of the vertebra has some risks but many advantages over other types of fixation (e.g., wires, hooks). For example, there is less movement in screws compared with wires or hooks. This increased stability of the fixation device reduces the risk that the hardware will poke into the spinal canal damaging the spinal cord. Likewise, there is less risk of injury to blood vessels in the area.

Pedicle screws are also able to give better correction of the spinal deformity by providing multiplanar correction. Vertebral bones are able to rotate, flex, and extend as well as slide and glide slightly forward, back, and sideways. Multiplanar stabilization stops motion in all directions.

Studies show that pedicle screws used in the lumbar and thoracic spines of adolescents and adults are less likely to pull out or fail compared with hooks and wires. But what we don’t know is how well these screws work in the younger population. This study takes a look at the complication rate (and types of complications) in children up to age 12 compared with children between the ages of 13 and 18.

In this study, 726 pediatric patients who had a spinal (thoracic and/or lumbar) fusion were evaluated and reviewed for complications. Results were compared for children in the younger group (ages up to and including 12 years old) with those in the older group (ages 13 to 18). Rates of infection, hardware failure, and neurovascular (nerve tissue or blood vessel) problems were reported after at least one full year of follow-up.

Overall complication rates were 13.6 per cent for the younger group and 16.9 per cent in the adolescent group. Broken down by category, there was a 0.5 per cent rate for neurovascular complications in the younger group compared with 1.92 per cent among the adolescents. Hardware-related problems were 13.4 per cent (younger group) versus 15.4 per cent (older group). And the infection rate was 9.2 per cent (younger group) compared with 11 per cent among the older patients.

Other areas examined in this study were 1) number of screws used and risk of complication (no link between these two factors), 2) timing of neurovascular complications (all occurred within the first 24 hours), and most common late complications (screw prominence sometimes requiring screw removal). Very rarely, complications such as stroke during the surgery, aspiration pneumonia, failure of wound healing, and ileus (bowel blockage) were reported. Such complications were not directly caused by the use of pedicle screws but were associated with having major (spinal) surgery.

Superior correction of spinal deformity with fewer problems make pedicle screws (as a fixation device) the preferred choice of many surgeons. The study served its purpose to compare the rate of complications from the use of pedicle screws in these two age groups.

It looks like complications from the off-label use among younger children are no different than with the adolescent group. Compared with other types of fixation (hooks, wires, rods), pedicle screws have a lower rate of complications. Pedicle screws for spinal stabilization are considered by these authors as safe, reliable, and effective. This data may help spur other studies with the eventual outcome of FDA approval of pedicle screws for spinal stabilization in young children.