Spinal Growth after Transpedicular Instrumentation in One and Two Year Old Children - A Ten Year Follow-Up

Introduction: Congenital deformities should be corrected early before rigidity increases and before secondary structural curves develop. However, in young children the immature posterior elements do not allow for a stable fixation with hooks or wires. In a one or two year old child transpedicular instrumentation is the only option which ensures stable fixation. There is, however, a lack of long-term results regarding vertebral growth following transpedicular instrumentation in this age group.

Methods: Twenty-two operations in 19 one and two year old children were performed between 1991 and 2003. A total of 120 transpedicular screws were inserted; 20 in the upper thoracic spine (T1-T4), 26 in the midthoracic spine (T5-T9), 53 in the thoracolumbar region (T10-L1), and 21 in the lumbar spine (L2-S1). Screw diameter was 3.5 mm. Five patients (group 1) were evaluated with a minimum follow-up of 10 years, 14 patients (group 2) with a follow-up of 2 to 10 years.

Results: None of the patients showed neurologic deficits, neither by placement of the screws nor during further growth. MRI or CT studies were performed in 3 patients of group 1; they showed no stenosis of the spinal canal. Radiographic results demonstrated growth of the instrumented vertebral bodies comparable to adjacent vertebrae. Complications of pedicle screws: 6 malpositions (5%), 2 screw breakages (1.7%), and one pedicle fracture (0.8%).

Discussion: The results suggest that pedicle screw fixation can be performed safely in one and two year old children without adverse effects on vertebral growth. Transpedicular screws allow for stable fixation with three dimensional control of the vertebral body and transmission of adequate correction forces. Although transpedicular screws cross the neurocentral synchondrosis, no stenosis of the spinal canal was observed. Vertical growth of the vertebral bodies against posterior transpedicular instrumentation, which acts as a tension band, results in increasing lordosis.

Hibbs Award Nominee for Best Clinical Paper