Departments of1Neurological Surgery and.
2Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota.
J Neurosurg Spine. 2021 Jan 15;34(4):617-622. doi: 10.3171/2020.8.SPINE20742. Print 2021 Apr 1.
Pelvic incidence (PI) is a commonly utilized spinopelvic parameter in the evaluation and treatment of patients with spinal deformity and is believed to be a fixed parameter. However, a fixed PI assumes that there is no motion across the sacroiliac (SI) joint, which has been disputed in recent literature. The objective of this study was to determine if patients with SI joint vacuum sign have a change in PI between the supine and standing positions.
A retrospective chart review identified patients with a standing radiograph, supine radiograph, and CT scan encompassing the SI joints within a 6-month period. Patients were grouped according to their SI joints having either no vacuum sign, unilateral vacuum sign, or bilateral vacuum sign. PI was measured by two independent reviewers.
Seventy-three patients were identified with an average age of 66 years and a BMI of 30 kg/m2. Patients with bilateral SI joint vacuum sign (n = 27) had an average absolute change in PI of 7.2° (p < 0.0001) between the standing and supine positions compared to patients with unilateral SI joint vacuum sign (n = 20) who had a change of 5.2° (p = 0.0008), and patients without an SI joint vacuum sign (n = 26) who experienced a change of 4.1° (p = 0.74). ANOVA with post hoc Tukey test showed a statistically significant difference in the change in PI between patients with the bilateral SI joint vacuum sign and those without an SI joint vacuum sign (p = 0.023). The intraclass correlation coefficient between the two reviewers was 0.97 for standing PI and 0.96 for supine PI (p < 0.0001).
Patients with bilateral SI joint vacuum signs had a change in PI between the standing and supine positions, suggesting there may be increasing motion across the SI joint with significant joint degeneration.
骨盆入射角（PI）是评估和治疗脊柱畸形患者时常用的脊柱骨盆参数，被认为是一个固定参数。然而，固定的 PI 假设骶髂关节（SI）没有运动，这在最近的文献中受到了争议。本研究的目的是确定是否存在 SI 关节真空征的患者在仰卧位和站立位之间 PI 会发生变化。
回顾性图表审查确定了在 6 个月内同时具有站立位 X 光片、仰卧位 X 光片和包括 SI 关节的 CT 扫描的患者。根据他们的 SI 关节是否存在单侧真空征、双侧真空征或无真空征将患者分为三组。PI 由两名独立的观察者进行测量。
共确定了 73 名患者，平均年龄为 66 岁，BMI 为 30 kg/m2。与单侧 SI 关节真空征患者（n = 20）相比，双侧 SI 关节真空征患者（n = 27）的 PI 在站立位和仰卧位之间的平均绝对变化为 7.2°（p < 0.0001），而单侧 SI 关节真空征患者的变化为 5.2°（p = 0.0008），无 SI 关节真空征患者（n = 26）的变化为 4.1°（p = 0.74）。ANOVA 与事后 Tukey 检验显示，双侧 SI 关节真空征患者与无 SI 关节真空征患者的 PI 变化之间存在统计学显著差异（p = 0.023）。两名观察者之间站立位 PI 的组内相关系数为 0.97，仰卧位 PI 的组内相关系数为 0.96（p < 0.0001）。
存在双侧 SI 关节真空征的患者在仰卧位和站立位之间 PI 发生变化，表明 SI 关节可能存在随着关节退变而增加的运动。
