Abstract：
BACKGROUND: Pedicle subtraction osteotomy (PSO) is effective for correcting spinal malalignment but is associated with high complication rates. The biomechanical effect of different PSO levels remains unclear, and no finite element (FE) analysis has compared L2-, L3-, L4-, and L5-PSOs.
OBJECTIVE: To assess the effects of PSO level on the spine\'s global range of motion, stresses on posterior instrumentation, load sharing with the anterior column, and proximal junctional stresses.
METHODS: A computational biomechanical analysis.
METHODS: A validated 3D spinopelvic FE model (T10-Pelvis) was used to perform PSOs at L2, L3, L4 and L5. Each model was instrumented with a four-rod configuration (primary rods + in-line satellite rods) from T11-Pelvis. Simulation included a 2-step analysis; (1) applying 300 N to thoracic, 400 N to lumbar, and 400 N to sacrum, and (2) applying a 7.5 Nm moment to the top endplate of the T10 vertebral body. Acetabulum surfaces were fixed in all degrees of freedom. The range of motion, spinopelvic parameters (lumbar lordosis (LL), sacral slope (SS), pelvic incidence (PI), and pelvic tilt (PT)), PSO force, and von Mises stresses were measured. All models were compared with the L3-PSO model and percentage differences were captured.
RESULTS: Compared to the intact alignment: LL increased by 48%, 45%, 59%, and 56% in the L2-, L3-, L4-, and L5-PSO models; SS increased by 25%, 15%, and 11% while PT decreased by 76%, 53%, and 45% in L2-, L3-, and L4-PSOs (SS and PT approximated intact model in L5-PSO); Lumbar osteotomy did not affect the PI. Compared to L3-PSO: L2-, L4-, and L5-PSOs showed up to 32%, 34%, and 34% lower global ROM. The least T10-T11 ROM was observed in L5-PSO. The left and right SIJ ROM were approximately similar in each model. Amongst all, the L5-PSO model showed the least ROM at the SIJ. Compared to L3-PSO, the L2-, L4-, and L5-PSO models showed up to 67%, 61%, and 78% reduced stresses at the UIV, respectively. Minimum stress at UIV+ was observed in the L3-PSO model. The L2-and L3-PSOs showed the maximum PSO force. The L5-PSO model showed the lowest stresses on the primary rods in all motions.
CONCLUSIONS: Our FE investigation indicates that L5-PSO results in the greatest lumbar lordosis and lowest global, SIJ, and T10-T11 ROMs and stresses on the primary rods, suggesting potential mechanical benefits in reducing the risk of rod breakage. However, L4- and L5-PSOs led to the least force across the osteotomy site, which may increase the risk of pseudarthrosis. These findings provide biomechanical insights that may inform surgical planning, though further clinical investigation is essential to determine the optimal PSO level and validate these results.
CONCLUSIONS: Understanding the biomechanical impact of PSO level is crucial for optimizing surgical outcomes and minimizing the risks of post-operative complications.
OBJECTIVE: To assess the effects of PSO level on the spine\'s global range of motion, stresses on posterior instrumentation, load sharing with the anterior column, and proximal junctional stresses.
METHODS: A computational biomechanical analysis.
METHODS: A validated 3D spinopelvic FE model (T10-Pelvis) was used to perform PSOs at L2, L3, L4 and L5. Each model was instrumented with a four-rod configuration (primary rods + in-line satellite rods) from T11-Pelvis. Simulation included a 2-step analysis; (1) applying 300 N to thoracic, 400 N to lumbar, and 400 N to sacrum, and (2) applying a 7.5 Nm moment to the top endplate of the T10 vertebral body. Acetabulum surfaces were fixed in all degrees of freedom. The range of motion, spinopelvic parameters (lumbar lordosis (LL), sacral slope (SS), pelvic incidence (PI), and pelvic tilt (PT)), PSO force, and von Mises stresses were measured. All models were compared with the L3-PSO model and percentage differences were captured.
RESULTS: Compared to the intact alignment: LL increased by 48%, 45%, 59%, and 56% in the L2-, L3-, L4-, and L5-PSO models; SS increased by 25%, 15%, and 11% while PT decreased by 76%, 53%, and 45% in L2-, L3-, and L4-PSOs (SS and PT approximated intact model in L5-PSO); Lumbar osteotomy did not affect the PI. Compared to L3-PSO: L2-, L4-, and L5-PSOs showed up to 32%, 34%, and 34% lower global ROM. The least T10-T11 ROM was observed in L5-PSO. The left and right SIJ ROM were approximately similar in each model. Amongst all, the L5-PSO model showed the least ROM at the SIJ. Compared to L3-PSO, the L2-, L4-, and L5-PSO models showed up to 67%, 61%, and 78% reduced stresses at the UIV, respectively. Minimum stress at UIV+ was observed in the L3-PSO model. The L2-and L3-PSOs showed the maximum PSO force. The L5-PSO model showed the lowest stresses on the primary rods in all motions.
CONCLUSIONS: Our FE investigation indicates that L5-PSO results in the greatest lumbar lordosis and lowest global, SIJ, and T10-T11 ROMs and stresses on the primary rods, suggesting potential mechanical benefits in reducing the risk of rod breakage. However, L4- and L5-PSOs led to the least force across the osteotomy site, which may increase the risk of pseudarthrosis. These findings provide biomechanical insights that may inform surgical planning, though further clinical investigation is essential to determine the optimal PSO level and validate these results.
CONCLUSIONS: Understanding the biomechanical impact of PSO level is crucial for optimizing surgical outcomes and minimizing the risks of post-operative complications.
摘要：
背景：椎弓根减影截骨术（PSO）可有效纠正脊柱排列不良，但并发症发生率高。不同PSO水平的生物力学效应尚不清楚。没有有限元(FE)分析比较L2-，L3-,L4-,和L5-PSO。
目的：为了评估PSO水平对脊柱整体运动范围的影响，强调后部仪器，与前柱的载荷分担，和近端连接应力。
方法：计算生物力学分析。
方法：使用经过验证的3D脊柱骨盆FE模型（T10-Pelvis）在L2，L3，L4和L5进行PSO。每个模型都配备了来自T11-Pelvis的四杆配置（主杆直列卫星杆）。模拟包括两步分析；(1)对胸部应用300N，400N至腰部,和400N到骶骨，和(2)对T10椎体的顶端板施加7.5Nm的力矩。髋臼表面在所有自由度上都是固定的。运动的范围，骨盆脊髓参数(腰椎前凸(LL)，骶骨斜坡(SS),骨盆发病率（PI），和骨盆倾斜（PT）），PSO部队,并测量了冯·米塞斯的应力。将所有模型与L3-PSO模型进行比较,并且捕获百分比差异。
结果：与完整比对相比：LL增加了48%，45%,59%,在L2-中占56%，L3-,L4-,和L5-PSO模型；SS增加了25%，15%,11%，PT下降76%，53%,和45%在L2-，L3-,和L4-PSO（L5-PSO中SS和PT近似完整模型）；腰椎截骨术不影响PI。与L3-PSO相比：L2-，L4-,L5-PSO显示高达32%，34%,全球ROM降低了34%。在L5-PSO中观察到最少的T10-T11ROM。每个模型中的左侧和右侧SIJROM大致相似。其中,L5-PSO模型在SIJ显示的ROM最少。与L3-PSO相比，L2-,L4-,L5-PSO模型显示高达67%，61%,在UIV处减少了78%的应力，分别。在L3-PSO模型中观察到UIV+处的最小应力。L2-和L3-PSO显示最大PSO力。L5-PSO模型显示，在所有运动中，主杆上的应力最低。
结论：我们的有限元研究表明，L5-PSO导致腰椎前凸最大，全球最低，SIJ,T10-T11ROM和主杆上的应力，提示潜在的机械好处，以降低杆断裂的风险。然而,L4-和L5-PSO导致穿过截骨部位的力最小，这可能会增加假关节的风险。这些发现提供了生物力学见解，可以为手术计划提供信息，尽管进一步的临床研究对于确定最佳PSO水平并验证这些结果至关重要。
结论：了解PSO水平的生物力学影响对于优化手术结果和降低术后并发症的风险至关重要。
目的：为了评估PSO水平对脊柱整体运动范围的影响，强调后部仪器，与前柱的载荷分担，和近端连接应力。
方法：计算生物力学分析。
方法：使用经过验证的3D脊柱骨盆FE模型（T10-Pelvis）在L2，L3，L4和L5进行PSO。每个模型都配备了来自T11-Pelvis的四杆配置（主杆直列卫星杆）。模拟包括两步分析；(1)对胸部应用300N，400N至腰部,和400N到骶骨，和(2)对T10椎体的顶端板施加7.5Nm的力矩。髋臼表面在所有自由度上都是固定的。运动的范围，骨盆脊髓参数(腰椎前凸(LL)，骶骨斜坡(SS),骨盆发病率（PI），和骨盆倾斜（PT）），PSO部队,并测量了冯·米塞斯的应力。将所有模型与L3-PSO模型进行比较,并且捕获百分比差异。
结果：与完整比对相比：LL增加了48%，45%,59%,在L2-中占56%，L3-,L4-,和L5-PSO模型；SS增加了25%，15%,11%，PT下降76%，53%,和45%在L2-，L3-,和L4-PSO（L5-PSO中SS和PT近似完整模型）；腰椎截骨术不影响PI。与L3-PSO相比：L2-，L4-,L5-PSO显示高达32%，34%,全球ROM降低了34%。在L5-PSO中观察到最少的T10-T11ROM。每个模型中的左侧和右侧SIJROM大致相似。其中,L5-PSO模型在SIJ显示的ROM最少。与L3-PSO相比，L2-,L4-,L5-PSO模型显示高达67%，61%,在UIV处减少了78%的应力，分别。在L3-PSO模型中观察到UIV+处的最小应力。L2-和L3-PSO显示最大PSO力。L5-PSO模型显示，在所有运动中，主杆上的应力最低。
结论：我们的有限元研究表明，L5-PSO导致腰椎前凸最大，全球最低，SIJ,T10-T11ROM和主杆上的应力，提示潜在的机械好处，以降低杆断裂的风险。然而,L4-和L5-PSO导致穿过截骨部位的力最小，这可能会增加假关节的风险。这些发现提供了生物力学见解，可以为手术计划提供信息，尽管进一步的临床研究对于确定最佳PSO水平并验证这些结果至关重要。
结论：了解PSO水平的生物力学影响对于优化手术结果和降低术后并发症的风险至关重要。
