Coronal and sagittal plane correction in patients with Lenke 1 adolescent idiopathic scoliosis: a comparison of consecutive versus interval pedicle screw placement

Abstract

Study design: Prospective clinical study.

Objective: The aim of this study was to compare postoperative outcome in patients with Lenke 1 adolescent idiopathic scoliosis (AIS) after posterior correction and fusion with consecutive or interval pedicle screw constructs on the correction side.

Summary of background data: Despite reports of satisfactory correction and maintenance of scoliotic curves after consecutive pedicle screw instrumentation on the correction side, there has been no comparison of outcome after consecutive versus interval pedicle screw placement.

Methods: Thirty patients with Lenke 1 AIS were randomly divided into 2 groups. In 1 group, posterior fusion was performed using consecutive pedicle screw placement on the correction side, whereas in the other, an interval placement construct was employed. The following variables were assessed preoperatively and postoperatively (between 2 and 4.1 y) to ascertain curve correction: thoracic coronal and sagittal Cobb angle and global coronal and sagittal balance.

Results: There were no preoperative or surgical between group differences for any variable. Thoracic coronal Cobb angle significantly decreased from 60.7+/-11.7 to 15.5+/-7.88 and from 61.87+/-9.93 to 15.67+/-7.35 in the consecutive and interval placement groups. Thoracic sagittal Cobb angle significantly decreased from 27.3+/-10.6 to 21.5+/-11.7 and from 27.1+/-9.83 to 22.0+/-11.3 in the consecutive and interval placement groups. Global sagittal balance significantly decreased from -2.33+/-5.05 to 1.33+/-3.22 and from -3.40+/-4.76 to 0.80+/-2.93 in the consecutive and interval placement groups. There were no between group differences for any postoperative measure. No neurologic complications of surgery were apparent in either group.

Conclusions: Interval pedicle screw placement constructs seem to be equally effective as consecutive constructs for facilitating curve correction in patients with Lenke 1 AIS.