Impact of Pregnancy on Loss of Deformity Correction After Pedicle Screw Instrumentation for Adolescent Idiopathic Scoliosis

Objective: A retrospective multicenter comparative study was carried out to evaluate whether pregnancy leads to the loss of deformity correction (LOC) in female patients surgically treated for idiopathic scoliosis. Methods: A total of 128 female patients who underwent segmental spinal instrumentation and fusion for adolescent idiopathic scoliosis (AIS) between 1999 and 2014 were reviewed. Of these patients, 62 became pregnant (surgery-pregnancy group [SPG]), whereas 66 did not (surgery-nonpregnancy [SNP] group). Radiographic parameters were analyzed before surgery, after surgery, before pregnancy, up to 1 year after delivery, and at final follow-up (FFU). Health-related quality of life was analyzed using the Scoliosis Research Society outcome questionnaire (SRS-22r). Results: The mean age at the time of surgery was 16 years in both groups. The mean preoperative major curves were 65° (standard deviation [SD], 12°) versus 67° (SD, 11°), 18° (SD, 9°) versus 17° (SD, 9°) immediately after surgery, and 20° (SD, 8°) versus 20° (SD, 8°) at FFU in the SPG and SNP groups, respectively (P > 0.10 for all comparisons). The mean loss of correction was 3.5° (SD, 3°) in the SPG and 4.5 (SD, 3°) for SNP groups, respectively (P = 0.379). The mean preoperative thoracic kyphosis (T5-T12) was 26.5° (SD, 11.9°) for SPG and 24.7° (SD, 14.5°) for SNP, after surgery 19.2° (SD, 9.5°) for SPG, 18.8 (SD, 8.9°) for SNP and at FFU, 20.3° (SD, 9°) for SPG and 21.3° (SD, 8.5°) for SNP. Conclusions: Women who have undergone pedicle screw instrumentation and fusion who have had ≥1 pregnancies do not have curve progression or deterioration in the longer-term outcomes compared with patients who have not become pregnant.