** PEDICLE SCREW FIXATION IN PEDIATRIC SPINAL DEFORMITIES – RESULTS IN PATIENTS UNDER 10 YEARS OLD

Se–ll Suk, M.D.;
Won–Joong Kim, M.D.;
Jin–Hyok Kim, M.D.;
Sang–Min Lee, M.D.;
Ewy– Ryong Jung, M.D.;
Hong–Moon Sohn, M.D.
Inje University Sanggye Paik Hospital, Seoul, Korea

Pedicle screw fixation offering enhanced deformity correction and maintenance is gaining increasing popularity for the correction of spinal deformities. However, there have been few reports on the results of pedicle screw fixation in pediatric spinal deformities especially for patients under 10 years old.

PURPOSE:
To determine the efficacy of pedicle screw fixation in pediatric spinal deformities and to evaluate the long–term effects of pedicle screw fixation on the growing spine.

MATERIALS AND METHODS:
Thirty–eight consecutive patients under the chronological age of 10 years subjected to pedicle screw instrumentation for a spinal deformity were analyzed after a minimum follow up of 2 years (2–7 years). There were 16 males and 22 females with a mean age of 6.9 years at the time of the operation (2–10 years). Etiologic diagnosis was congenital scoliosis/kyphosis in 25, idiopathic scoliosis in 9, and others in 4. They were reviewed using the medical records, preoperative, intraoperative and the roentgenograms taken at the last follow up for deformity correction and complications. To evaluate the effect of pedicle screws on the growing spine, a thin slice CT scan was performed at the last follow up in 27 patients (72%).

RESULTS:
The frontal plane deformity correction was 75% for idiopathic scoliosis (preop. 61°, postop. 16°), 56% for congenital (preop. 40°; postop. 16°). and 76% for other scoliosis (preop. 88°, postop. 22°). Loss of initial correction was 7.7%, 6.3% and 5.6% respectively. The sagittal plane deformity correction was mean 20° for kyphotic deformities (preop. 33°; postop. 13°) with a loss of initial correction of 3°(9.1%). A total of 341 pedicle screws were inserted with a mean of 8.9 screws per patient. The diameter of the screws ranged from 4.0 to 5.0 mm. With pre–drilling, screws up to 115% of the pedicle diameter could be inserted without causing pedicle fractures. Seven screw malpositions (2.1%) were observed in 5 patients. They were lateral in 3 (0.9%), superior in 2 (0.6%) and inferior in 2 (0.6%). Loss of fixation occurred in one of the malpositioned screws. There was 1 recurrence of deformity attributable to short fusion and 1 infection. There were no significant screw related neurologic or vascular complications. Symptoms or radiologic features suggestive of spinal stenosis were not detected in any of the patients.

CONCLUSIONS:
Pedicle screw fixation may be used with the same efficacy for pediatric spinal deformities even in patients under 10 years old without hazard of iatrogenic spinal stenosis or neurologic complications.

** The FDA has not cleared a drug and/or medical device for the use described in this presentation. (i.e., the drug or medical device is being discussed in an “off–label: use).