Calculation of the Target Lumbar Lordosis Angle for Restoring an Optimal Pelvic Tilt in Elderly Patients With Adult Spinal Deformity

Abstract Background: To date, there is a paucity of reports clarifying the change of spinopelvic parameters in patients with adult spinal deformity (ASD) who underwent long segment spinal fusion using iliac screw (IS) and S2-alar-iliac screw (S2AI) fixation.Methods: A retrospective review of consecutive patients underwent deformity correction surgery for ASD between 2013 and 2017 was performed. Patients were divided into two groups based on whether IS or S2AI fixation was performed. All radiographic parameters were measured preoperatively, immediately postoperatively, and the last follow-up. Demographics, intraoperative and clinical data were analyzed between the two groups. Additionally, the cohort was subdivided according to the postoperative change in pelvic incidence (PI): subgroup (C) was defined as change in PI ≥5° and subgroup (NC) with change <5°. In subgroup analyses, the 2 different types of postoperative change of PI were directly compared.Results: A total of 142 patients met inclusion criteria: 111 who received IS and 31 received S2AI fixation. The IS group (65.6 ± 26, 39.8 ± 13.8) showed a significantly higher change in lumbar lordosis (LL) and upper lumbar lordosis (ULL) than the S2AI group (54.4 ± 17.9, 30.3 ± 9.9) (p<0.05). In subgroup (C), PI significantly increased from 53° preoperatively to 59° postoperatively at least 50% of IS cohort, with a mean change of 5.8° (p<0.05). The clinical outcomes at the last follow-up were significantly better in IS group than in S2AI group in terms of VAS scores for back and leg. The occurrence of sacroiliac joint pain and pelvic screw fracture were significantly greater in S2AI group than in IS group (25.8% vs 9%, p<0.05) and (16.1% vs 3.6%, p<0.05).Conclusions: IS fixation showed a greater change in LL and ULL than S2AI fixation in ASD surgery. PI may be changed under certain circumstances.

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Supine Imaging Is a Superior Predictor of Long-Term Alignment Following Adult Spinal Deformity Surgery

Global Spine Journal ◽

10.1177/2192568220960753 ◽

2020 ◽

pp. 219256822096075

Author(s):

Jonathan Charles Elysee ◽

Francis Lovecchio ◽

Renaud Lafage ◽

Bryan Ang ◽

Alex Huang ◽

...

Keyword(s):

Spinal Deformity ◽

Lumbar Lordosis ◽

Pelvic Incidence ◽

Lumbar Fusion ◽

Adult Spinal Deformity ◽

Multilinear Regression ◽

Sagittal Vertical Axis ◽

Type Curve ◽

Scoliosis Research Society ◽

Correlation Analyses

Study Design: Retrospective cohort study. Objective: To investigate correlations between preoperative supine imaging and postoperative alignment. Methods: A retrospective review was conducted of a single-institution database of patients with adult spinal deformity (ASD). Patients were stratified by fusion location in the lumbar or thoracic spine. Outcomes of interest were postoperative lumbar lordosis (LL) and thoracic kyphosis (TK). Sagittal alignment parameters were compared and correlation analyses were performed. Multilinear stepwise regression was conducted to identify independent predictors of postoperative LL or TK. Regression analyses were repeated within the lumbar and thoracic fusion cohorts. Results: A total of 99 patients were included (mean age 63.2 years, 83.1% female, mean body mass index 27.3 kg/m2). Scoliosis Research Society classification demonstrated moderate to severe sagittal and/or coronal deformity (pelvic tile modifier, 18.2% ++; sagittal vertical axis, 27.3% ++, pelvic incidence minus lumbar lordosis mismatch, 29.3% ++, SRS type, 29.3% N type curve and 68.7% L or D type curve). A total of 73 patients (73.7%) underwent lumbar fusion and 50 (50.5%) underwent thoracic fusion. Correlation analyses demonstrated a significant association between pre- and postoperative LL and TK. Multilinear regression demonstrated that LL supine and pelvic incidence were significant predictors of postoperative LL ( r 2 = 0.568, P < .001). LL supine, TK supine, and age were significant predictors of postoperative TK ( r 2 = 0.490, P < .001). Conclusion: Preoperative supine films are superior to standing in predicting postoperative alignment at 1-year follow-up. Anticipation of undesired alignment changes through supine imaging may be useful in mitigating the risk of iatrogenic malalignment.

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Does MIS Surgery Allow for Shorter Constructs in the Surgical Treatment of Adult Spinal Deformity?

Neurosurgery ◽

10.1093/neuros/nyw072 ◽

2017 ◽

Vol 80 (3) ◽

pp. 489-497 ◽

Cited By ~ 18

Author(s):

Juan S. Uribe ◽

Joshua Beckman ◽

Praveen V. Mummaneni ◽

David Okonkwo ◽

Pierce Nunley ◽

...

Keyword(s):

Length Of Stay ◽

Blood Loss ◽

Clinical Outcomes ◽

Spinal Deformity ◽

Lumbar Lordosis ◽

Adult Spinal Deformity ◽

Radiographic Parameters ◽

Estimated Blood Loss ◽

Significant Difference ◽

The Impact

Abstract BACKGROUND: The length of construct can potentially influence perioperative risks in adult spinal deformity (ASD) surgery. A head-to-head comparison between open and minimally invasive surgery (MIS) techniques for treatment of ASD has yet to be performed. OBJECTIVE: To examine the impact of MIS approaches on construct length and clinical outcomes in comparison to traditional open approaches when treating similar ASD profiles. METHODS: Two multicenter databases for ASD, 1 involving MIS procedures and the other open procedures, were propensity matched for clinical and radiographic parameters in this observational study. Inclusion criteria were ASD and minimum 2-year follow-up. Independent t-test and chi-square test were used to evaluate and compare outcomes. RESULTS: A total of 1215 patients were identified, with 84 patients matched in each group. Statistical significance was found for mean levels fused (4.8 for circumferential MIS [cMIS] and 10.1 for open), mean interbody fusion levels (3.6 cMIS and 2.4 open), blood loss (estimated blood loss 488 mL cMIS and 1762 mL open), and hospital length of stay (6.7 days cMIS and 9.7 days open). There was no significant difference in preoperative radiographic parameters or postoperative clinical outcomes (Owestry Disability Index and visual analog scale) between groups. There was a significant difference in postoperative lumbar lordosis (43.3° cMIS and 49.8° open) and pelvic incidence-lumbar lordosis correction (10.6° cMIS and 5.2° open) in the open group. There was no significant difference in reoperation rate between the 2 groups. CONCLUSION: MIS techniques for ASD may reduce construct length, reoperation rates, blood loss, and length of stay without affecting clinical and radiographic outcomes when compared to a similar group of patients treated with open techniques.

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Upper instrumented vertebra–femoral angle and correlation with proximal junctional kyphosis in adult spinal deformity

Spine Deformity ◽

10.1007/s43390-021-00408-1 ◽

2021 ◽

Author(s):

Hao-Hua Wu ◽

Dean Chou ◽

Kevork Hindoyan ◽

Jeremy Guinn ◽

Joshua Rivera ◽

...

Keyword(s):

Femoral Head ◽

Spinal Deformity ◽

Lumbar Lordosis ◽

Adult Spinal Deformity ◽

Surgical Correction ◽

Proximal Junctional Kyphosis ◽

Upper Instrumented Vertebra ◽

Femoral Head Center ◽

Junctional Kyphosis

Abstract Introduction Although matching lumbar lordosis (LL) with pelvic incidence (PI) is an important surgical goal for adult spinal deformity (ASD), there is concern that overcorrection may lead to proximal junctional kyphosis (PJK). We introduce the upper instrumented vertebra–femoral angle (UIVFA) as a measure of appropriate postoperative position in the setting of lower thoracic to pelvis surgical correction for patients with sagittal imbalance. We hypothesize that a more posterior UIV position in relation to the center of the femoral head is associated with an increased risk of PJK given compensatory hyperkyphosis above the UIV. Methods In this retrospective cohort study, adult patients undergoing lower thoracic (T9–T12) to pelvis correction of ASD with a minimum of 2-year follow-up were included. UIVFA was measured as the angle subtended by a line from the UIV centroid to the femoral head center to the vertical axis. Patients who developed PJK and those who did not were compared with preoperative and postoperative UIVFA as well as change between postoperative and preoperative UIVFA (deltaUIVFA). Results Of 119 patients included with an average 3.6-year follow-up, 51 (42.9%) had PJK and 24 (20.2%) had PJF. Patients with PJK had significantly higher postoperative UIVFA (12.6 ± 4.8° vs. 9.4 ± 6.6°, p = 0.04), deltaUIVFA (6.1 ± 7.6° vs. 2.1 ± 5.6°, p < 0.01), postoperative pelvic tilt (27.3 ± 9.2 vs. 23.3 ± 11, p = 0.04), postoperative lumbar lordosis (47.7 ± 13.9° vs. 42.4 ± 13.1, p = 0.04) and postoperative thoracic kyphosis (44.9 ± 13.2 vs. 31.6 ± 18.8) than patients without PJK. With multivariate logistic regression, postoperative UIVFA and deltaUIVFA were found to be independent risk factors for PJK (p < 0.05). DeltaUIVFA was found to be an independent risk factor for PJF (p < 0.05). A receiver operating characteristic (ROC) curve for UIVFA as a predictor for PJK was established with an area under the curve of 0.67 (95% CI 0.59–0.76). Per the Youden index, the optimal UIVFA cut-off value is 11.5 degrees. Conclusion The more posterior the UIV is from the femoral head center after lower thoracic to pelvis surgical correction for ASD, the more patients are at risk for PJK. The greater the magnitude of posterior translation of the UIV from the femoral head center from preop to postop, the greater the likelihood for PJF.

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Understanding sagittal compensation in adult spinal deformity patients: relationship between pelvic tilt and lower-extremity position

Journal of Neurosurgery Spine ◽

10.3171/2021.1.spine201660 ◽

2021 ◽

pp. 1-8

Author(s):

Takayoshi Shimizu ◽

Meghan Cerpa ◽

Lawrence G. Lenke

Keyword(s):

Lower Extremity ◽

Spinal Deformity ◽

Knee Flexion ◽

Pelvic Tilt ◽

Adult Spinal Deformity ◽

The Other ◽

Whole Body ◽

Shift Group ◽

Posterior Shift ◽

Full Body

OBJECTIVE In adult spinal deformity (ASD), quantifying preoperative lower-extremity (LE) compensation is important in formulating an operative plan to achieve optimal global sagittal alignment. Whole-body radiographs are not always available. This study evaluated the possibility of estimating LE compensation without whole-body radiographs. METHODS In total, 200 consecutive ASD patients with full-body radiographic assessment were categorized into the following three groups according to their cranio-hip balance (distance from the cranial sagittal vertical axis to the hip axis [CrSVA-H]): group 1, anterior-shift (A-shift) group (CrSVA-H > 40 mm); group 2, balanced group, −40 mm < CrSVA-H < 40 mm; and group 3, posterior-shift (P-shift) group, CrSVA-H < −40 mm. After analyzing the correlation between CrSVA-H, pelvic tilt (PT), and LE parameters, the cutoff PT and PT/pelvic incidence (PI) values that correlated with the presence of LE compensation were determined. Previously published data from asymptomatic volunteers were used as a baseline threshold (sacrofemoral angle [SFA] > 217.0° and knee flexion angle [KA] > 11.0°). RESULTS Among the hip, knee, and ankle, only KA showed a significant increase in the A-shift group compared to the other two groups (p < 0.01). With a wide threshold (SFA > 208.0° and KA > 5.0°), 84.9% of the A-shift group showed LE compensation (hip or knee or both), which was a significantly greater percentage than those in the balanced and P-shift groups (48.4% and 51.9%, p < 0.01). With a narrow threshold (SFA > 217.0° and KA > 11.0°), 62.2% of the A-shift group showed any LE compensation, which was also a higher percentage than the other two groups. The CrSVA-H was moderately correlated with KA (r = 0.502), but had no correlation with PT, SFA, and ankle dorsiflexion angle (AA). PT showed a moderate/strong correlation with SFA, KA, and AA (r = 0.846, 0.624, and 0.622, respectively). With receiver operating characteristic curves, the authors determined that a 23.0° PT with PT/PI > 0.46 predicts the presence of any type of LE compensation with use of the wide threshold. CONCLUSIONS ASD patients with increased CrSVA-H, which represents cranio-hip anterior imbalance, demonstrated a higher prevalence of LE compensation, especially knee flexion, compared to those with neutral and posterior shift of CrSVA. PT represents the extent of LE compensation in patients with spinal sagittal malalignment. Using the cutoff value of PT determined in this study, surgeons can preoperatively estimate the extent of LE compensation without obtaining a full-body radiograph.

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