A new study published in Spinal Deformity examines the risk factors for proximal junctional kyphosis among adolescent idiopathic scoliosis patients.
The study authors examined data from 851 adolescent idiopathic scoliosis patients from 2000 to 2011. The researchers found:
1. The proximal junctional kyphosis rate was 7.05 percent. The PJK rate varied by Lenke type:
• Lenke 1: 6.35 percent
• Lenke 2: 4.39 percent
• Lenke 3: 11.64 percent
• Lenke 4: 4.39 percent
• Lenke 5: 8.49 percent
• Lenke 6: 11.64 percent
2. The risk factors for PJK among Lenke 1 curve patients included:
• Kyphosis loss postoperatively
• Stopping caudal to the upper end vertebra
With each lost kyphosis degree, the risk of PJK increased 7.1 percent.
3. Kyphosis loss and more lordotic rod contour angle were associated with higher risk for PJK among patients with Lenke 2 and 4 curves.
4. The only significant risk factor for PJK among patients with Lenke 3 and 6 curves was larger postoperative T5-T12 kyphosis. For Lenke 5 curve patients, PJK risk increased with upper instrumented vertebra or cephalad to the upper end vertebra.
5. There wasn't a significant correlation between the sagittal pelvic parameters and PJK.