Manzetti Marco, Ruffilli Alberto, Viroli Giovanni, Traversari Matteo, Ialuna Marco, Petitoni Chiara Ricci, Faldini Cesare
1st Orthopaedic and Traumatologic Clinic - IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy.
Department of Biomedical and Neuromotor Science-DIBINEM, University of Bologna, Bologna, Italy.
Spine Deform. 2025 May 8. doi: 10.1007/s43390-025-01103-1.
Pelvic incidence (PI) is traditionally considered a constant anatomic parameter in adult spinal deformity (ASD) surgery. However, emerging evidence suggests that PI may change postoperatively, potentially influencing sagittal balance and mechanical complications. This study aims to systematically review the literature on postoperative PI variations in ASD patients, identifying potential radiologic and surgical predictors.
Papers describing postoperative PI changes in ASD patients were included in the analysis. The rate of PI changes, in different subgroups of patients was considered for outcome measure. Meta-analyses were performed to determine the prevalence and factors influencing PI changes.
Thirteen studies (1055 patients) met the inclusion criteria. All included studies assessed spinopelvic parameters using standing full-spine X-rays, except for one that used full-body standing X-rays, demonstrating moderate\high reproducibility in PI measurement (ICC: 0.71-0.96). While the mean absolute PI value remained stable postoperatively, 46.3% of patients experienced significant changes (> 5°). Factors associated with PI variations included fusion area, pelvic fixation type, preoperative sagittal imbalance, and extreme PI values. Sacropelvic fixation reduced PI instability, whereas prolonged anterior imbalance and compensatory pelvic retroversion increased the likelihood of PI shifts. Long-term follow-ups indicated that PI changes could not recover or increase in patients without sacropelvic fixation and in patients with higher preoperative PI values if they experience a decrease in PI postoperatively.
The current literature challenges the traditional belief that PI is a static parameter in ASD surgery, particularly in severely imbalanced patients or those with extreme PI values. Acknowledging that PI may change under certain preoperative conditions could help optimize postoperative sagittal realignment in selected groups of ASD patients.
在成人脊柱畸形（ASD）手术中，骨盆入射角（PI）传统上被认为是一个恒定的解剖学参数。然而，新出现的证据表明，PI术后可能会发生变化，这可能会影响矢状面平衡和机械并发症。本研究旨在系统回顾关于ASD患者术后PI变化的文献，确定潜在的影像学和手术预测因素。
分析中纳入了描述ASD患者术后PI变化的论文。将不同患者亚组中PI变化的发生率作为结局指标。进行荟萃分析以确定PI变化的发生率和影响因素。
13项研究（1055例患者）符合纳入标准。除一项使用全身站立位X线片的研究外，所有纳入研究均使用站立位全脊柱X线片评估脊柱骨盆参数，显示PI测量具有中度/高度可重复性（组内相关系数：0.71 - 0.96）。虽然术后PI的平均绝对值保持稳定，但46.3%的患者出现了显著变化（>5°）。与PI变化相关的因素包括融合区域、骨盆固定类型、术前矢状面失衡和PI极值。骶骨盆固定可降低PI的不稳定性，而长期的前路失衡和代偿性骨盆后倾会增加PI移位的可能性。长期随访表明，没有骶骨盆固定的患者以及术前PI值较高且术后PI降低的患者，PI变化无法恢复或增加。
当前文献对传统观念提出了挑战，即PI在ASD手术中是一个静态参数，尤其是在严重失衡的患者或PI值极端的患者中。认识到PI在某些术前条件下可能会发生变化，有助于优化特定ASD患者群体的术后矢状面重新排列。
