Gravity Line-Hip Axis Offset as a Guide for Global Alignment to Prevent Recurrent Proximal Junctional...

Area of Science:

• Orthopedic Surgery
• Spine Surgery
• Deformity Correction

Background:

• Proximal junctional kyphosis/failure (PJK/F) is a significant complication following adult spinal deformity (ASD) corrective surgery.
• Recurrent PJK/F necessitates further surgery and can lead to neurological deficits.
• Global sagittal balance, assessed by the gravity line (GL), is crucial in spinal alignment.

Purpose of the Study:

• To investigate the postoperative gravity line-hip axis (GL-HA) offset as a risk factor for recurrent PJK/F.
• To determine if GL-HA offset influences the likelihood of PJK/F recurrence after revision surgery for ASD.

Main Methods:

• Retrospective review of adult spinal deformity patients who underwent revision surgery for PJK/F.
• Categorization into recurrent and non-recurrent PJK/F groups.
• Analysis of demographic, surgical, and spinopelvic alignment parameters, including postoperative GL-HA offset.

Main Results:

• 32 patients without recurrent PJK/F and 28 with recurrent PJK/F were analyzed.
• No significant differences in baseline demographics or surgical characteristics were found between groups.
• Postoperative GL-HA offset < -52.6 mm was a significant predictor of recurrent PJK/F (OR=7.0, P=.003).

Conclusions:

• Postoperative GL-HA offset is a critical risk factor for recurrent PJK/F in ASD revision surgery.
• Overcorrection (GL-HA offset < -5 cm) is associated with a higher incidence of recurrent PJK/F.
• The spine may overcompensate to align the GL near the hip axis, potentially at the expense of the proximal junction.