Vertebral Bone Quality Score Independently Predicts Proximal Junctional Kyphosis and/or Failure After Adult Spinal Deformity Surgery

MRI-based L1 Vertebral Bone Quality Scores Predict Cage Subsidence Following Transforaminal Lumbar Interbody Fusion Similar to L1 CT Hounsfield Units

Cage subsidence is one of the most common complications after transforaminal lumbar interbody fusion (TLIF) and correlates with inferior bone quality. Studies have reported L1 vertebral bone quality score (VBQ) based on MRI to be a promising alternative to evaluating preoperative bone quality. However, to the knowledge of the authors, no study has examined the correlation between L1 VBQ scores and cage subsidence after TLIF.The purpose of the study was (1) to assess the interrelation between the L1 VBQ score and cage subsidence after TLIF; and (2) to compare L1 VBQ and L1 CT Hounsfield Unit (HU) values in predicting cage subsidence after TLIF.We reviewed patients who had undergone TLIF at one institution between 2012 to 2021. Cage subsidence was measured using postoperative lumbar CT based on cage protrusion through the endplates at more than 2 mm. The L1 VBQ score was calculated by dividing mean L1 signal intensity (SI) by mean SI of the cerebrospinal fluid (CSF) at L1. The L1 HU value representing bone mineral density (BMD) was measured using computed tomography. We then performed Student's t-test for independent samples and logistic regression analyses for statistical analysis. We also conducted receiver operating characteristic (ROC) analysis to assess the predictive ability of the L1 VBQ score and L1 CT HU.Of 233 participants, cage subsidence was observed in 41 patients (17.6%). Comparison between the characteristics of patients between the group with subsidence and the group without subsidence revealed significant differences in the age, VBQ score, and L1 CT HU. Multivariate logistic regression showed that higher L1 VBQ score (OR = 2.499, 95% CI: 1.205-5.180, p = 0.014) and lower L1 CT HU (OR = 0.960, 95% CI: 0.933-0.987, p = 0.005) were associated with an increased rate of cage subsidence. Area under the curve (AUC) analysis of the L1 VBQ score returned 0.735 (95% CI: 0.620-0.850) and the suitable threshold was 3.424 (sensitivity: 82.9%, specificity: 70.7%). The AUC of L1 CT HU was 0.747 (95% CI: 0.642-0.852) and the suitable threshold was 136.5 (sensitivity: 85.4%, specificity: 56.1%).The present study demonstrates that L1 VBQ score and L1 CT HU are reliable predictors with similar performance for cage subsidence after TLIF.

S1 Vertebral Bone Quality Score Independently Predicts Proximal Junctional Kyphosis After Posterior Hemivertebra Resection With Transpedicular Instrumentation

OBJECTIVE

Proximal junctional kyphosis (PJK) is a prevalent postoperative complication after posterior hemivertebra (HV) resection. Previous research has demonstrated a strong correlation between the development of PJK and reduced bone mineral density. The vertebral bone quality (VBQ) score, derived from magnetic resonance imaging, is considered a predictive and evaluative tool for bone mineral density. However, obtaining accurate magnetic resonance imaging signal intensity at the L1-L4 vertebrae is challenging in patients with HV. Consequently, a novel S1 VBQ score has been proposed, which exhibits high accuracy. This study aimed to evaluate the efficacy of S1 VBQ scores in predicting the incidence of PJK in these patients.

METHODS

We conducted a retrospective analysis of patients diagnosed with HV who underwent posterior HV resection with transpedicular instrumentation at our department from 2010 to 2020. Comprehensive demographic and radiographic data were collected. To identify potential preoperative risk factors for the incidence of PJK, we utilized the least absolute shrinkage and selection operator method. Subsequently, a multivariate logistic regression model was constructed to evaluate the risk factors identified through the least absolute shrinkage and selection operator analysis. Cutoff values were determined through receiver operating characteristic analysis to assess the predictive value of the S1 VBQ score for PJK.

RESULTS

A total of 88 patients met the inclusion criteria, with 14 patients (15.9%) developing PJK. Five potential risk factors were selected, including S1 VBQ scores, Risser sign, thoracic kyphosis, pelvic tilt, and proximal junctional angle. The multivariate logistic regression model demonstrated that the S1 VBQ score is an independent risk factor for predicting PJK. The area under the receiver operating characteristic curve (area under the curve) for S1 VBQ scores was 0.770 with an optimal threshold of 2.793 (sensitivity: 78.6%, specificity: 67.6%).

CONCLUSION

A higher S1 VBQ score is an independent risk factor for PJK, with a diagnostic accuracy of 77%. The S1 VBQ threshold of 2.793 was found to be effective in identifying PJK.

LEVEL OF EVIDENCE

Level III.

Iatrogenic posterior translation of the construct at the uppermost instrumented vertebrae is associated with proximal junctional kyphosis

PURPOSE

To determine if iatrogenic posterior translation (UIV SPi) at the upper instrumented vertebrae (UIV) is associated with increased mechanical complications and secondarily to generate and validate a UIV SPi threshold for increased complications.

METHODS

Two patient databases were utilized: one for generating a UIV SPi threshold and another for validation. Patients with a UIV between T8-L1 and a LIV at ilium were included. A receiver operating curve (ROC) curve analyses was performed to generate a threshold that predicted proximal junctional complications. This UIV SPi angle (-16.0°) was rounded to -15.0° for practical clinical use and validated in a separate cohort. Patients were stratified as above (most translated, MT) or below (least translated, LT) the threshold for comparative demographic and outcomes analyses.

RESULTS

Generation of the threshold on 192 patients (122 LT, 70 MT) revealed that the MT group had higher absolute postoperative UIV SVA (MT=-56.1 ± 23.1 mm vs. LT=-10.4 ± 31.8 mm, p < 0.001), higher PT (25.7° vs. 19.3°, p < 0.001), and 2.8-5.8 times greater odds of postoperative proximal junctional complications at 2-years (p < 0.05). Validation on 135 patients (95 LT, 40 MT) revealed that the MT group had 11.7 times greater odds of radiographic PJK and had 4.5 times greater odds of all-cause reoperations (p < 0.05).

CONCLUSION

Patients with UIV posterior translation, despite similar PI-LL and T1PA, exhibit a high PT and experience higher odds of proximal junctional complications. Our findings support limiting the UIV SPi to < 15° of posterior translation to mitigate postoperative mechanical complications.

LEVEL OF EVIDENCE

IV.

Analysis of Magnetic Resonance Imaging-Based Vertebral Bone Quality Scores in Patients with Degenerative Lumbar Scoliosis

BACKGROUND

Degenerative lumbar scoliosis (DLS) often causes various issues such as neural symptoms and osteoporosis (OP). Vertebral bone quality (VBQ) is a crucial factor that surgeons take into consider prior to surgery. However, little attention has been given to the use of VBQ in evaluating vertebral bone mass in DLS patients. The aim of this study was to investigate the ability of magnetic resonance imaging-based VBQ score to evaluate bone mass in patients with DLS and its ability to predict OP.

METHODS

A total of 120 patients were enrolled and divided into the DLS and non-DLS groups. The VBQ scores of the L1-L4 vertebral bodies were measured in noncontrast T1-weighted imaging. Dual-energy X-ray absorptiometry (DXA) was used to assess osteoporotic status. Additionally, patients with DLS were divided into 2 groups: with vertebral rotatory subluxation (VRS) and without VRS. The VBQ scores, computed tomography (CT) values, and DXA indicators were compared between the DLS and non-DLS groups, and between VRS and non-VRS groups. VBQ was compared with the CT value, bone density, and T-score using the Pearson correlation coefficient. VBQ was obtained according to the non-DLS group and compared with the accuracy of diagnosing OP with DXA.

RESULTS

The DLS group was significantly different from the non-DLS group in terms of the VBQ score (3.53 vs. 2.98), CT value (109.81 vs. 134.60), T score (-1.19 vs. -1.72), and bone mineral density value (1.04 vs. 0.94). The VRS group presented a larger Cobb angle, lower CT value, and higher VBQ score. The area under the curve of the VBQ score in the prediction of OP was 0.804, with a sensitivity of 68.4% and a specificity of 85.7%.

CONCLUSIONS

VBQ can reduce interference from degeneration and deformities and can be used as a complementary method for vertebral quality assessment.

Evaluation of predictive performance for new vertebral compression fracture between Hounsfield units value and vertebral bone quality score following percutaneous vertebroplasty or kyphoplasty

RATIONALE AND OBJECTIVES

New vertebral compression fractures (NVCF) are very common in patients following percutaneous vertebroplasty (PVP) or kyphoplasty (PKP). The study aims to evaluate the comparative predictive performance of vertebral bone quality (VBQ) score and Hounsfield units (HU) value in forecasting NVCF after surgery.

MATERIALS AND METHODS

This study retrospectively analyzed patients who underwent PVP/PKP at our institution between 2020 and 2021. The VBQ score and HU value were obtained from preoperative magnetic resonance imaging (MRI) and computed tomography (CT) scans, respectively. Subsequently, the forecasting capabilities of these two parameters were assessed by contrasting their receiver operating characteristic (ROC) curve.

RESULTS

A total of 303 eligible patients (56 with NVCF and 247 without) were identified in the study. Six relevant literature factors were identified and included in the multivariate analysis revealed that lower HU value (OR = 0.967, 95% CI = 0.953-0.981, P < 0.001) and higher VBQ score (OR = 3.964, 95% CI = 2.369-6.631, P < 0.001) emerged as independent predictors of NCVF occurrence. Compared to the ROC curve of the HU value, demonstrating a diagnostic accuracy of 83.2% (95% CI = 77.5%-88.9%, P < 0.001), the VBQ score was 85.8%. And, a statistically significant negative correlation was observed between the VBQ score and the T-score (r = -0.529, P < 0.001).

CONCLUSION

In patients undergoing PVP/PKP, VBQ score, and HU value are independently associated with the occurrence of NVCF. Assessing the HU value and the VBQ score could play an effective role in planning PVP/PKP operations.

MRI-based endplate bone quality scores outperform vertebral bone quality scores in predicting adjacent segment disease following transforaminal lumbar interbody fusion

PURPOSE

This study aims to (1) evaluate whether the endplate bone quality (EBQ) scores can independently predict adjacent segment disease (ASD); and (2) judge the predictive value of EBQ compared to vertebral bone quality (VBQ) for ASD after single-level transforaminal lumbar interbody fusion (TLIF).

METHODS

A single-center retrospective analysis was conducted of patients undergoing single-level TLIF for degenerative spinal disease from 2014 to 2020. Demographic, surgery, and radiographic data were collected. Logistic regression was used to identify independent risk factors for ASD. Furthermore, a receiver operating curve (ROC) analysis was conducted to evaluate the predictive efficacy of the EBQ score and VBQ score.

RESULTS

The rate of ASD was 16.4% at a minimum 24-month follow-up. Significant risk factors for ASD were higher VBQ score (OR = 3.418, 95%CI: 1.297-9.008, P = 0.013), higher EBQ score (OR = 2.469, 95%CI: 1.085-5.621, P = 0.031), and higher adjacent segment Pfirrmann grade (OR = 2.866, 95%CI: 1.765-4.653, P<0.001). The diagnostic accuracy of VBQ and EBQ for distinguishing ASD were 0.806 (95%CI: 0.728-0.883) and 0.835 (95%CI: 0.757-0.912). The optimal threshold of VBQ scores was 2.926 (sensitivity: 90.6%, specificity: 62.0%) and of EBQ was 3.511 (sensitivity: 90.6%, specificity: 71.8%).

CONCLUSION

Higher VBQ and EBQ scores are both independent risk factors of ASD after single-segment TLIF surgery, and EBQ scores perform better in predicting ASD. When EBQ > 3.511, there is a considerable risk of ASD.

Determining the risk factors for postoperative mechanical complication in degenerative scoliosis: a machine learning approach based on musculoskeletal metrics

OBJECTIVE

To determine the risk factors for mechanical complications (MC) following corrective surgery for degenerative scoliosis through a machine learning (ML) algorithm.

METHODS

Patients with degenerative scoliosis who received corrective surgery were enrolled. A total of 213 cases were ultimately included and randomized into the training set (70%) and test set (30%) to develop the machine learning-based algorithm. The demographic data, comorbidities, regional and global radiographic parameters, paraspinal muscle (PSM) fat infiltration rate (FI%), and vertebral bone quality (VBQ) score were analyzed.

RESULTS

A total of 101 patients (47.4%) had MC, including 46 patients with proximal junctional kyphosis or failure (PJK/PJF), 7 patients with distal junctional kyphosis or failure (DJK/DJF), and 25 patients with rod or screw breakage. In the testing set, Gaussian Naive Bayes (GNB) exhibited the highest AUC at 0.77, while Random Forest (RF) exhibited the highest PRC at 0.63. GNB, RF, and Logistic Regression (LR) models all achieved an accuracy of 0.69, while RF exhibited the highest sensitivity at 0.60 and lowest Brier score of 0.20. Shapley Additive Explanation (SHAP) analysis identified higher FI% of PSM, elevated VBQ score, higher preoperative T1-pelvic angle (T1PA), and postoperative lordosis maldistribution as major risk factors for MC. Based on RF model, local interpretable model-agnostic explanations (LIME) visualization was successfully developed for individual risk calculation.

CONCLUSION

The RF and GNB models showed the best overall performance. Both RF and GNB models identified top-ranked/major risk factors including higher paraspinal muscle fat infiltration, elevated VBQ score, higher preoperative T1PA angle, and postoperative lordosis maldistribution providing valuable insights for surgical decision-making.

The Paraspinal Sarcopenia at the Upper Instrumented Vertebra Is a Predictor of Discoligamentous but Not Bony Proximal Junctional Kyphosis

Background/Objectives: Both poor bone quality and paraspinal sarcopenia have been suggested as risk factors for proximal junctional kyphosis (PJK) at the upper instrumented vertebra (UIV) following long-segment thoracolumbar fusion. Methods: Adults ≥50 with a T1-6 UIV were identified, and data were gathered on pre- and postoperative spinopelvic parameters, bone quality (using Hounsfield units and vertebral bone quality score), and paraspinal cross-sectional area at L3 and the UIV. PJK was defined by a ≥10° increase in the proximal junctional angle. Cox regressions were performed to identify PJK risk factors; PJK was subdivided into types 1-3 based on the Yagi-Boachie classification. Results: In total, 15/76 patients (median age 66; 72.4% female) experienced PJK; 10 experienced type 1, 4 experienced type 2, and one experienced type 3. Univariable Cox regression showed that PJK was negatively correlated with total paraspinal muscle CSA at the UIV (HR 0.74/100 mm2; 95% CI [0.57, 0.6]; p = 0.02). Lower total paraspinal CSA at L3 (HR 0.94/100 mm2; p = 0.07) and higher postoperative global tilt (HR 1.03; p = 0.09) also trended toward significance. Similarly, type 1 PJK was predicted by smaller total paraspinal CSA at the UIV (HR 0.64/100 mm2; [0.45, 0.92]; p = 0.02). Paraspinal CSA was not predictive of type 2 PJK, but lower HU at the UIV and UIV + 1 trended toward significance (HR 0.98/unit; p = 0.16). A comparison of type 1 and 2 PJK showed a higher average of paraspinal CSA and a lower average of HU at the UIV. Conclusions: Global alignment and paraspinal sarcopenia were most predictive of PJK, though paraspinal sarcopenia was only predictive of type 1. Type 2 may be better predicted by bone quality.

Risk Factors of Proximal Junctional Failure After Adult Spinal Deformity Surgery: A Systematic Review and Meta-Analysis

OBJECTIVE

This study aimed to identify surgical, patient-specific, and radiographic risk factors for proximal junctional failure (PJF), a complex complication following adult spinal deformity (ASD) surgery.

METHODS

A systematic literature search was performed using PubMed, Embase, and the Cochrane Library. The literature on the risk factors for PJF after ASD surgery was included. The study patients were diagnosed with ASD and underwent surgery for ASD. PJF is defined as the occurrence of proximal junctional kyphosis, accompanied by one or more of the following characteristics: a fracture of the vertebral body at the upper instrumented vertebra (UIV) or UIV + 1 level, disruption of the posterior ligaments, or dislodgement of the instrumentation at the UIV. proximal junctional kyphosis, on the other hand, is determined by 2 criteria: a proximal junctional sagittal Cobb angle 1) of 10° and 2) at least 10° greater than the preoperative value.

RESULTS

Our pooled analysis of 11 unique studies (2037 patients) revealed significant differences in several preoperative and postoperative measures between PJF and non-PJF groups.

CONCLUSIONS

In ASD patients, the presence of concurrent osteoporosis or paravertebral muscle wasting significantly increases the risk of developing PJF. The use of bicortical screws, UIV screw angle exceeding 1°, and positioning the UIV in the lower thoracic or lumbar region also further elevate this risk. Lower preoperative SS, higher preoperative PI-LL, higher preoperative pelvic tilt, higher preoperative SVA, higher postoperative LL, and a greater change in LL characterize patients with PJF.

Anterior Column Realignment Through Open Pre-posterior Release-Anterior-Posterior Fusion Versus Hybrid Minimally Invasive-Anterior-Posterior Fusion for Dynamic Sagittal Imbalance of the Spine

STUDY DESIGN

Retrospective comparative study.

OBJECTIVES

To investigate the clinical and radiological outcomes after anterior column realignment (ACR) through pre-posterior release-anterior-posterior surgery (PAP) and minimally invasive surgery -lateral lumbar interbody fusion (MIS-LLIF) using hybrid anterior-posterior surgery (AP).

METHODS

A total of 91 patients who underwent ACR with long fusions from T10 vertebra to the sacropelvis with a follow-up period of at least 2 years after corrective surgery for adult spinal deformity were included and divided into two groups by surgical method: AP and PAP. AP was performed in 26 and PAP in 65 patients. Clinical outcomes and radiological parameters were investigated and compared. A further comparison was conducted after propensity score matching between the groups.

RESULTS

The more increase of LL and decrease of PI-LL mismatch were observed in the PAP group than in the AP group postoperatively. After propensity score matching, total operation time and intraoperative bleeding were greater, and intensive care unit care and rod fracture were more frequent in the PAP group than in the AP group with statistical significance. Reoperation rate was higher in PAP (29.2%) than in AP (16.7%) without statistical significance.

CONCLUSIONS

PAP provides a more powerful correction for severe sagittal malalignment than AP procedures. AP results in less intraoperative bleeding, operation time, and postoperative complications. Therefore, this study does not suggest that one treatment is superior to the other.

LEVEL OF EVIDENCE

III.

Vertebral Bone Quality Score as a Predictor of Subsequent Fractures After Cement Augmentation for Osteoporotic Vertebral Compression Fracture

BACKGROUND AND OBJECTIVES

Dual-energy X-ray absorptiometry (DXA) T-scores have been shown to predict fragility fractures in population-based studies. Recently, a novel MRI-based vertebral bone quality (VBQ) score has been proposed, showing better predictability for fragility fractures compared with DXA T-scores. The aim of this study was to explore the correlation between VBQ scores and DXA T-scores and to determine the impact of VBQ scores on the risk of subsequent fragility fractures after cement augmentation for osteoporotic vertebral compression fracture (OVCF).

METHODS

Between January and December 2018, 251 consecutive patients who received cement augmentation for OVCF were included in the study. VBQ scores were calculated using noncontrast T1-weighted MRI. Correlations between VBQ and T-scores were assessed. Patients were divided into 2 groups based on the presence or absence of subsequent fragility fractures after cement augmentation: (1) no Subsequent fracture group and (2) subsequent fracture group. Comparisons between the groups were conducted, and risk factors of subsequent fractures were evaluated using multivariable logistic regression analysis.

RESULTS

Of the patients, 42 (16.7%) experienced subsequent fractures after cement augmentation. The VBQ score showed moderate correlations with the T-score of the hip (r = -0.523, P < .001) and the T-score of the lumbar spine (r = -0.383, P < .001). The subsequent fracture group had a significantly higher VBQ score (4.02 ± 0.56 vs 3.52 ± 0.62, P < .001) and a worse T-score of hip (-3.06 ± 1.28 vs -2.42 ± 0.98, P = .004). In the multivariable analysis, the VBQ score was the only independent predictor of subsequent fractures with 2.799 odds ratio (1.342 to 5.841, P = .006).

CONCLUSION

In patients who received cement augmentation for OVCF, the VBQ score is significantly correlated with the DXA T-score and may be a more reliable predictor of subsequent fragility fractures.

Sagittal Imbalance in Degenerative Kyphosis: Prevalence and Implication on Postoperative Mechanical Failure

BACKGROUND AND OBJECTIVES

To explore the patterns of sagittal imbalance in patients with lumbar or thoracolumbar degenerative kyphosis (DK) and determine its implication for the risk of mechanical complication (MC) after corrective surgery.

METHODS

A total of 137 patients with DK who underwent corrective surgery were reviewed. The patients were divided into L group (with a kyphotic apex at L2 and below) and TL group (with kyphotic apex at L1 and above). Then, sacral slope (SS) (defined as S1 if SS > 0 in TL, or SS > 10 in L group) and sagittal vertical axis ≥ 5 cm (defined as +) were used as modifier sagittal balance. The Scoliosis Research Society (SRS)-22 questionnaire scores were analyzed, and the risk of mechanical failure was compared across groups.

RESULTS

The distribution of subgroups was 38 (27.7%) in TLS1(-) group, 36 (26.3%) in TLS1(+) group, 16 (11.7%) in TLS0(-) group, and 5 (3.6%) in TLS0(+) group. For L group, the figure was 5 (3.6%) in LS1(-), 22 (16.1%) in LS1(+), 7 (5.2%) in LS0(-), and 8 (5.8%) in LS0(+). Patients in L group had significantly higher regional kyphosis, lower lumbar lordosis, and higher sagittal vertical axis, indicating a higher risk of global decompensation. The SRS function scores and pain scores were also lower in the L group compared with the TL group. At a minimum of 2 years of follow-up, χ 2 test showed that the incidence of TLS0 (+), LS0 (-), and LS0 (+) had significantly higher rates of MC (>40%). In both TL and L groups, patients with MC were found to have significantly lower bone mineral density than those without.

CONCLUSION

The findings decipher the distinct patterns of sagittal imbalance in severe DK patients with kyphotic apex at thoracolumbar or lumbar spine. Patients with kyphotic apex apex at L2 or below, low SS, and global imbalance showed the highest risk of postoperative mechanical failure.

Comparison of Predictive Performance for Pedicle Screw Loosening Between Computed Tomography-Based Hounsfield Units and Magnetic Resonance Imaging-Based Vertebral Bone Quality Score After Lumbar Surgery

OBJECTIVE

To compare predictive performance for pedicle screw loosening between computed tomography (CT)-based Hounsfield units (HU) and magnetic resonance imaging (MRI)-based vertebral bone quality score (VBQ) after lumbar surgery.

METHODS

A retrospective study was conducted on patients who received transforaminal lumbar interbody fusion continuously at our institution from May 2018 to September 2020. On the basis of 12 months' follow-up lumbar radiographs, screw loosening was defined as a clear zone of minimal thickness of ≥1 mm around the pedicle screw on radiography. VBQ score and HU value were measured using preoperative MRI and CT, respectively. Then, we evaluated the predictive performance of these 2 parameters by comparing the receiver operating characteristic curve.

RESULTS

In all patients, area under the curve (AUC) of the VBQ score (AUC = 0.752; 95% confidence interval [CI] 0.663-0.841; P < 0.001) was larger than those of the CT HU value (AUC = 0.652; 95% CI 0.558-0.746; P = 0.005), but there was no significant difference between them (PAUC = 0.076). In patients with lumbar spinal stenosis, AUC of VBQ score (AUC = 0.863; 95% CI 0.764-0.961; P < 0.001) was larger than those of the CT HU value (AUC = 0.673; 95% CI 0.513-0.833; P = 0.043), with significant difference (PAUC = 0.003).

CONCLUSIONS

MRI-based VBQ score and CT-based HU value have similar performance in predicting pedicle screw loosening after lumbar surgery. Furthermore, in patients with lumbar spinal stenosis, VBQ score demonstrated better predictive ability than HU value.

Hounsfield units and vertebral bone quality score for predicting mechanical complications after adult spinal deformity surgery: a systematic review and meta-analysis

The purpose of this systematic review and meta-analysis is to assess existing literature and determine the association between the Hounsfield unit (HU) value and the vertebral body quality (VBQ) score with mechanical complications (MCs) after adult spinal deformity (ASD) surgery. Although bone quality is considered an increasingly important factor for MCs after ASD surgery, the utility of the HU value assessed by computed tomography and the VBQ score assessed by magnetic resonance imaging remains unknown. A systematic review of PubMed, Embase, and Cochrane Library databases was performed to find studies evaluating the association between the HU value and the VBQ score with MCs after ASD surgery. In the subsequent meta-analysis, MC outcomes were combined using a random-effects model, and the standardized mean difference and 95% confidence interval were calculated. The final analysis included a total of 20 studies. Nineteen studies reported HU values, and two studies reported VBQ scores. Proximal junctional kyphosis/failure (PJK/PJF) was reported as the MC in 16 studies, whereas other MCs were included in 6 studies. Six studies with a pool of 506 patients with ASD revealed that preoperative HU values at the upper instrumented vertebra (UIV) and UIV+1 were significantly lower in patients with PJK/PJF (standardized mean difference, -0.74; 95% confidence interval, -1.09 to -0.40). Three studies suggested an cutoff HU value of approximately ≤120, yielding a pooled sensitivity of 0.77, specificity of 0.67, and diagnostic odds ratio of 7.01. However, two studies reported conflicting results on the relationship between the VBQ score and PJK/PJF. Low HU values predicted the risk of certain MCs, particularly PJK/PJF, after ASD surgery. An HU value of <120 should alert surgeons to be cautious about the postoperative occurrence of PJK/PJF. Future studies are needed to validate the cutoff HU value and evaluate the utility of the VBQ score.

[Correlation of Vertebral Bone Quality and Paraspinal Muscle Changes With Adjacent Segment Degeneration After Transforaminal Lumbar Interbody Fusion Operation]

Objective

To investigate the correlation of vertebral bone quality (VBQ) and paraspinal muscle changes with adjacent segment degeneration (ASD) after transforaminal lumbar interbody fusion (TLIF) through a retrospective analysis of patients who have undergone TLIF for lumbar degenerative diseases (LDD).

Methods

A total of 98 patients who underwent TLIF surgical treatment for LDD between January 2016 and December 2022 at Shenzhen People's Hospital were selected. Well-established follow-up imaging data were available for all subjects who were divided into two groups, the ASD group (n=43) and the non-ASD (N-ASD) group (n=55), according to whether they met the ASD evaluation criteria. Data on the basic characteristics of the patients in both groups were collected, and the relevant parameters, including VBQ and the total cross-sectional area (TCSA) and the functional cross-sectional area (FCSA) of psoas major (PM), erector spinae (ES), and multifidus (MF), were measured by magnetic resonance imaging of the lumbar spine performed preoperatively and at the last follow-up. Then, the relative fat infiltration (RFI) was calculated from the above metrics accordingly. Logistic regression analysis was conducted to investigate the risk factors for ASD.

Results

The incidence of ASD was 43.9% (n=43) at the final follow-up. The mean follow-up time was (27.23±4.15) months. The age, body mass index (BMI), preoperative bone mineral density (BMD), preoperative VBQ, ΔRFIPM, and ΔRFIES+MF showed significant differences between the ASD and N-ASD groups (P<0.05). According to the results of the logistic regression analysis, BMI (odds ratio [OR]=1.450, 95% confidence interval [CI]: 1.081-1.945, P=0.013), preoperative VBQ (OR=6.191, 95% CI: 1.692-22.657, P=0.006), and ΔRFIES+MF (OR=1.117, 95% CI: 1.007-1.238, P=0.037) were independent risk factors for ASD.

Conclusion

The incidence of postoperative ASD in patients who have undergone TLIF for LDD was found to be associated with higher BMI, preoperative VBQ, and increased postoperative relative fat infiltration of the ES and MF muscles. Consequently, it is advisable to prioritize the intraoperative protection of the paraspinal muscles during TLIF. In the postoperative period, it is essential to strengthen exercises of the lower back muscles and to optimize bone mass and weight management, which is conducive to reducing the risk of ASD in the postoperative period.

Magnetic Resonance Imaging-Based Vertebral Bone Quality Score for Prediction of Cage Subsidence and Screw Loosening in Patients Undergoing Degenerative Lumbar Surgery: A Meta-analysis

OBJECTIVE

Poor bone quality is a risk factor for postoperative complications after degenerative lumbar fusion surgery. The magnetic resonance imaging-based vertebral bone quality (VBQ) score is a good tool for assessing bone quality, and this is the first meta-analysis performed to summarize the predictive value of the VBQ score for cage subsidence and screw loosening in patients undergoing degenerative lumbar surgery.

METHODS

Studies were comprehensively searched in electronic databases. The quality of the studies was assessed. The pooled sensitivity, specificity and summary receiver operating characteristic curve were calculated. Publication bias was assessed and meta-regression was conducted.

RESULTS

We ultimately included 9 studies with a total of 1,404 patients with a mean age of 60.4 years and a percentage of females of 57.0%. According to the QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies 2) tool to assess methodological quality, the quality of the included studies was relatively low and risks of bias might exist. Results showed that a high VBQ was significantly associated with cage subsidence and screw loosening, and risk factor analysis revealed that the merged odds ratio was 5.37 for cage subsidence and 3.87 for screw loosening. With a VBQ cutoff value of 3.34±0.45, the pooled sensitivity and specificity for the diagnosis of postoperative complications were 0.75 and 0.75, respectively, and the area under the curve was 0.82 (95% confidence interval, 0.78-0.85).

CONCLUSION

A high VBQ was associated with a high risk of cage subsidence and screw loosening in patients who underwent degenerative lumbar surgery. The VBQ score could be considered for identifying high-risk patients for further evaluation.

Lumbar Lordosis Redistribution and Segmental Correction in Adult Spinal Deformity: Does it Matter?

STUDY DESIGN

Retrospective analysis of prospectively collected data.

OBJECTIVE

Evaluate the impact of correcting normative segmental lordosis values on postoperative outcomes.

BACKGROUND

Restoring lumbar lordosis magnitude is crucial in adult spinal deformity surgery, but the optimal location and segmental distribution remain unclear.

PATIENTS AND METHODS

Patients were grouped based on offset to normative segmental lordosis values, extracted from recent publications. Matched patients were within 10% of the cohort's mean offset, less than or over 10% were undercorrected and overcorrected. Surgical technique, patient-reported outcome measures, and surgical complications were compared across groups at baseline and two years.

RESULTS

In total, 510 patients with a mean age of 64.6, a mean Charlson comorbidity index 2.08, and a mean follow-up of 25 months. L4-5 was least likely to be matched (19.1%), while L4-S1 was the most likely (24.3%). More patients were overcorrected at proximal levels (T10-L2; undercorrected, U: 32.2% vs. matched, M: 21.7% vs. overcorrected, O: 46.1%) and undercorrected at distal levels (L4-S1: U: 39.0% vs. M: 24.3% vs. O: 36.8%). Postoperative Oswestry disability index was comparable across correction groups at all spinal levels except at L4-S1 and T10-L2/L4-S1, where overcorrected patients and matched were better than undercorrected (U: 32.1 vs. M: 25.4 vs. O: 26.5, P =0.005; U: 36.2 vs. M: 24.2 vs. O: 26.8, P =0.001; respectively). Patients overcorrected at T10-L2 experienced higher rates of proximal junctional failure (U: 16.0% vs. M: 15.6% vs. O: 32.8%, P <0.001) and had greater posterior inclination of the upper instrumented vertebrae (U: -9.2±9.4° vs. M: -9.6±9.1° vs. O: -12.2±10.0°, P <0.001), whereas undercorrection at these levels led to higher rates of revision for implant failure (U: 14.2% vs. M: 7.3% vs. O: 6.4%, P =0.025).

CONCLUSIONS

Patients undergoing fusion for adult spinal deformity suffer higher rates of proximal junctional failure with overcorrection and increased rates of implant failure with undercorrection based on normative segmental lordosis.

LEVEL OF EVIDENCE

Level IV.

Prediction of proximal junctional kyphosis and failure after corrective surgery for adult spinal deformity: an MRI-based model combining bone and paraspinal muscle quality metrics

BACKGROUND

Proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) are common complications observed after adult spinal deformity (ASD) surgery and major cause for unplanned reoperations. In addition to spinal alignment, osteoporosis and paraspinal muscle (PSM) degeneration are reportedly indispensable factors that account for PJK/PJF.

PURPOSE

To investigate the utility of the preoperative risk assessment model using MRI-based skeletomuscular metrics in predicting PJK and/or PJF(PJK/PJF) after ASD correction.

STUDY DESIGN

Retrospective case-control study.

PATIENT SAMPLE

Consecutive series of 149 patients at a single academic institution.

OUTCOME MEASURES

MRI-based measurements of vertebral bone quality at upper instrumented vertebra (VBQ-U) score and fat infiltration rate (FI%) of paraspinal muscle (PSM).

METHODS

We performed a retrospective analysis of patients with ASD who underwent ≥5-segment fusion. The vertebral bone quality (VBQ) scoring system was used to assess the bone quality. The PSM quality including FI% and cross-sectional area (CSA) was evaluated. Multivariate logistic regression was performed to determine potential risk factors of PJK/PJF.

RESULTS

Of 149 patients who underwent ASD surgery, PJK/PJF was found in 45(30.2%). Mean VBQ-U scores were 3.45±0.64 and 3.00±0.56 for patients with and without PJK/PJF (p<.001). Mean FI% of PSM(L3/L4) was 27.9±12.8 and 20.7±13.3 for patients with and without PJK/PJF (p<.001). On multivariate analysis, the VBQ-U score and FI% of PSM were significant independent predictors of PJK/PJF. The AUC for the novel risk assessment model is 0.806, with a predictive accuracy of 86.7%.

CONCLUSION

In patients undergoing ASD correction, paraspinal muscle and vertebral bone quality significantly outweigh radiographic alignment parameters in predicting PJK/PJF. The MRI-based risk assessment model offers a valuable tool for early assessing individualized risk for PJK/PJF.

Bone Health Optimization in Adult Spinal Deformity Patients: A Narrative Review

Osteoporosis and low bone mineral density (BMD) pose significant challenges in adult spinal deformity surgery, increasing the risks of complications such as vertebral compression fractures, hardware failure, proximal junctional kyphosis/failure, and pseudoarthrosis. This narrative review examines the current evidence on bone health optimization strategies for spinal deformity patients. Preoperative screening and medical optimization are crucial, with vitamin D supplementation showing particular benefit. Among the pharmacologic agents, bisphosphonates demonstrate efficacy in improving fusion rates and reducing hardware-related complications, though the effects may be delayed. Teriparatide, a parathyroid hormone analog, shows promise in accelerating fusion and enhancing pedicle screw fixation. Newer anabolic agents like abaloparatide and romosozumab require further study but show potential. Romosozumab, in particular, has demonstrated significant improvements in lumbar spine BMD over a shorter duration compared to other treatments. Surgical techniques like cement augmentation and the use of larger interbody cages can mitigate the risks in osteoporotic patients. Overall, a multifaceted approach incorporating medical optimization, appropriate pharmacologic treatment, and tailored surgical techniques is recommended to improve outcomes in adult spinal deformity patients with compromised bone quality. Future research should focus on optimizing the treatment protocols, assessing the long-term outcomes of newer agents in the spine surgery population, and developing cost-effective strategies to improve access to these promising therapies.

Systematic evaluation of vertebral bone quality score as an opportunistic screening method for BMD in spine surgery patients

PURPOSE

This study aimed to evaluate and compare the predictive value of vertebral bone quality (VBQ) score for low BMD and osteoporosis. Furthermore, we sought to enhance diagnostic effectiveness by integrating VBQ with easily accessible patient-specific factors.

METHODS

We retrospectively analyzed data from 180 patients. VBQ was obtained by preoperative MRI. Low BMD was classified as meeting the standards for either osteopenia or osteoporosis. The receiver operating characteristic curve analysis and multivariate logistic regression were used to detect the ability of variables to assess BMD. The z-test was used to compare the area under the curves of different variables.

RESULTS

VBQ was more effective in identifying low BMD than osteoporosis (AUC, 0.768 vs. 0.613, p = 0.02). Elevated VBQ (OR 6.912, 95% CI 2.72-17.6) and low BMI (0.858, 0.76-0.97) were risk factors for low BMD, while the risk factor for osteoporosis was age (1.067, 1.02-1.12), not VBQ. ROC analysis showed that AUCs were 0.613 for VBQ and 0.665 for age when screening for osteoporosis. The combined variable of VBQ, sex, age, and BMI obtained by logistic regression significantly improved the efficacy of BMD screening, with an AUC of 0.824 for low BMD and 0.733 for osteoporosis.

CONCLUSION

VBQ is better at detecting low BMD than identifying osteoporosis. The ability of VBQ to predict osteoporosis is limited, and a similar diagnostic efficacy can be achieved with age. Incorporating VBQ alongside demographic data enhances the efficiency of BMD assessment. With the development of artificial intelligence in medicine, this simple method is promising.

Vertebral Bone Quality Score as a Predictor of Adjacent Segment Disease After Lumbar Interbody Fusion

BACKGROUND AND OBJECTIVE

With lumbar spine fusion being one of the most commonly performed spinal surgeries, investigating common complications such as adjacent segment disease (ASD) is a high priority. To the authors' knowledge, there are no previous studies investigating the utility of the preoperative magnetic resonance imaging-based vertebral bone quality (VBQ) score in predicting radiographic and surgical ASD after lumbar spine fusion. We aimed to investigate the predictive factors for radiographic and surgical ASD, focusing on the predictive potential of the VBQ score.

METHODS

A single-center retrospective analysis was conducted of all patients who underwent 1-3 level lumbar or lumbosacral interbody fusion for lumbar spine degenerative disease between 2014 and 2021 with a minimum 12 months of clinical and radiographic follow-up. Demographic data were collected, along with patient medical, and surgical data. Preoperative MRI was assessed in the included patients using the VBQ scoring system to identify whether radiographic ASD or surgical ASD could be predicted.

RESULTS

A total of 417 patients were identified (mean age, 59.8 ± 12.4 years; women, 54.0%). Eighty-two (19.7%) patients developed radiographic ASD, and 58 (13.9%) developed surgical ASD. A higher VBQ score was a significant predictor of radiographic ASD in univariate analysis (2.4 ± 0.5 vs 3.3 ± 0.4; P < .001) and multivariate analysis (odds ratio, 1.601; 95% CI, 1.453-1.763; P < .001). For surgical ASD, a significantly higher VBQ score was seen in univariate analysis (2.3 ± 0.5 vs 3.3 ± 0.4; P < .001) and served as an independent risk factor in multivariate analysis (odds ratio, 1.509; 95% CI, 1.324-1.720; P < .001). We also identified preoperative disk bulge and preoperative existence of adjacent segment disk degeneration to be significant predictors of both radiographic and surgical ASD. Furthermore, 3-level fusion was also a significant predictor for surgical ASD.

CONCLUSION

The VBQ scoring system might be a useful adjunct for predicting radiographic and surgical ASD.

Optimizing preoperative bone health assessment for adult spinal deformity: a prospective correlation analysis of intraoperative pedicle screw insertion torque and imaging modalities in Japan

STUDY DESIGN

Prospective cohort study.

PURPOSE

This study aimed to identify the optimal preoperative bone health assessment for adult spinal deformity (ASD) surgery through correlation analysis between intraoperative pedicle screw (PS) insertion torque and various bone quality measures, including bone mineral density (BMD) assessed by dual-energy X-ray absorptiometry (DEXA), Hounsfield unit (HU) by computed tomography (CT), and vertebral bone quality (VBQ) score by magnetic resonance imaging.

OVERVIEW OF LITERATURE

Existing data on optimal assessment tools for ASD surgery are limited.

METHODS

The study included patients with ASD aged >60 years who underwent spinal corrective fusion surgery from the lower thoracic spine to the pelvis. The intraoperative PS insertion torque was measured using a torque meter. Pearson correlation coefficients were calculated between the PS insertion torque and the BMD, HU, and VBQ score. Preoperative bone quality was compared between the proximal junctional failure (PJF) and non-PJF groups.

RESULTS

Thirty-one patients with 177 PS at T10, T11, and T12 were analyzed. The PS insertion torque showed a moderate positive correlation with lumbar spine BMD (r=0.59-0.69, p<0.01), total hip BMD (0.58-0.62, p<0.01), and HU value (r=0.58-0.66, p<0.01). However, the VBQ score did not show significant correlation (r=-0.28 to -0.23, p >0.05). Notably, a strong correlation was found between the PS insertion torque and the HU value for screws of the same size (r=0.71 and 0.74, p<0.01). The HU value at T12 and the PS insertion torque at T10 were significantly lower in the PJF group than in the non-PJF group.

CONCLUSIONS

This study demonstrates a positive correlation between the PS insertion torque and HU value in the lower thoracic spine and a moderate correlation with BMD but not the VBQ score. Preoperative assessment using DEXA and CT is crucial for optimizing bone health management in ASD surgery.

Using advanced imaging to measure bone density, compression fracture risk, and risk for construct failure after spine surgery

Low bone mineral density (BMD) can predispose to vertebral body compression fractures and postoperative instrumentation failure. DEXA is considered the gold standard for measurement of BMD, however it is not obtained for all spine surgery patients preoperatively. There is a growing body of evidence suggesting that more routinely acquired spine imaging studies such as computed tomography (CT) and magnetic resonance imaging (MRI) can be opportunistically used to measure BMD. Here we review available studies that assess the validity of opportunistic screening with CT-derived Hounsfield Units (HU) and MRI-derived vertebral vone quality (VBQ) to measure BMD of the spine as well the utility of these measures in predicting postoperative outcomes. Additionally, we provide screening thresholds based on HU and VBQ for prediction of osteopenia/ osteoporosis and postoperative outcomes such as cage subsidence, screw loosening, proximal junctional kyphosis, and implant failure.

The influence of osteoporosis on mechanical complications in lumbar fusion surgery: a systematic review

Background

Adults undergoing spine surgery often have underlying osteoporosis, which may be a risk factor for postoperative complications. Although these associations have been described, osteoporosis remains profoundly underdiagnosed and undertreated in the spine surgery population. A thorough, comprehensive systematic review summarizing the relationships between bone mineral density (BMD) and specific complications of lumbar fusion surgery could be a valuable resource for raising awareness and supporting clinical practice changes.

Methods

PubMed, Embase, and Web of Science databases were searched for original clinical research articles reporting on BMD, or surrogate measure, as a predictor of complications in adults undergoing elective lumbar fusion for degenerative disease or deformity. Endpoints included cage subsidence, screw loosening, pseudarthrosis, vertebral fracture, junctional complications, and reoperation.

Results

A total of 71 studies comprising 12,278 patients were included. Overall, considerable heterogeneity in study populations, methods of bone health assessment, and definition and evaluation of clinical endpoints precluded meta-analysis. Nevertheless, low BMD was associated with higher rates of implant failures like cage subsidence and screw loosening, which were often diagnosed with concomitant pseudarthrosis. Osteoporosis was also a significant risk factor for proximal junctional kyphosis, particularly due to fracture. Many studies found surgical site-specific BMD to best predict focal complications. Functional outcomes were inconsistently addressed.

Conclusions

Our findings suggest osteoporosis is a significant risk factor for mechanical complications of lumbar fusion. These results emphasize the importance of preoperative osteoporosis screening, which allows for medical and surgical optimization of high-risk patients. This review also highlights current practical challenges facing bone health evaluation in patients undergoing elective surgery. Future prospective studies using standardized methods are necessary to strengthen existing evidence, identify optimal predictive thresholds, and establish specialty-specific practice guidelines. In the meantime, an awareness of the surgical implications of osteoporosis and utility of preoperative screening can provide for more informed, effective patient care.

Bone Quality as Measured by Hounsfield Units More Accurately Predicts Proximal Junctional Kyphosis than Vertebral Bone Quality Following Long-Segment Thoracolumbar Fusion

OBJECTIVE

To compare the prognostic power of Hounsfield units (HU) and Vertebral Bone Quality (VBQ) score for predicting proximal junctional kyphosis (PJK) following long-segment thoracolumbar fusion to the upper thoracic spine (T1-T6).

METHODS

Vertebral bone quality around the upper instrumented vertebrae (UIV) was measured using HU on preoperative CT and VBQ on preoperative MRI. Spinopelvic parameters were also categorized according to the Scoliosis Research Society-Schwab classification. Univariable analysis to identify predictors of the occurrence of PJK and survival analyses with Kaplan-Meier method and Cox regression were performed to identify predictors of time to PJK (defined as ≥10° change in Cobb angle of UIV+2 and UIV). Sensitivity analyses showed thresholds of HU < 164 and VBQ > 2.7 to be most predictive for PJK.

RESULTS

Seventy-six patients (mean age 66.0 ± 7.0 years; 27.6% male) were identified, of whom 15 suffered PJK. Significant predictors of PJK were high postoperative pelvic tilt (P = 0.038), high postoperative T1-pelvic angle (P = 0.041), and high postoperative PI-LL mismatch (P = 0.028). On survival analyses, bone quality, as assessed by the average HU of the UIV and UIV+1 was the only significant predictor of time to PJK (odds ratio [OR] 3.053; 95% CI 1.032-9.032; P = 0.044). VBQ measured using the UIV, UIV+1, UIV+2, and UIV-1 vertebrae approached, but did not reach significance (OR 2.913; 95% CI 0.797-10.646; P = 0.106).

CONCLUSIONS

In larger cohorts, VBQ may prove to be a significant predictor of PJK following long-segment thoracolumbar fusion. However, Hounsfield units on CT have greater predictive power, suggesting preoperative workup for long-segment thoracolumbar fusion benefits from computed tomography versus magnetic resonance imaging alone to identify those at increased risk of PJK.

Can We Rely on Prophylactic Two-Level Vertebral Cement Augmentation in Long-Segment Adult Spinal Deformity Surgery to Reduce the Incidence of Proximal Junctional Complications?

Background and Objectives: Proximal junctional kyphosis (PJK) and failure (PJF), the most prevalent complications following long-segment thoracolumbar fusions for adult spinal deformity (ASD), remain lacking in defined preventive measures. We studied whether one of the previously reported strategies with successful results-a prophylactic augmentation of the uppermost instrumented vertebra (UIV) and supra-adjacent vertebra to the UIV (UIV + 1) with polymethylmethacrylate (PMMA)-could also serve as a preventive measure of PJK/PJF in minimally invasive surgery (MIS). Materials and Methods: The study included 29 ASD patients who underwent a combination of minimally invasive lateral lumbar interbody fusion (MIS-LLIF) at L1-2 through L4-5, all-pedicle-screw instrumentation from the lower thoracic spine to the sacrum, S2-alar-iliac fixation, and two-level balloon-assisted PMMA vertebroplasty at the UIV and UIV + 1. Results: With a minimum 3-year follow-up, non-PJK/PJF group accounted for fifteen patients (52%), PJK for eight patients (28%), and PJF requiring surgical revision for six patients (21%). We had a total of seven patients with proximal junctional fracture, even though no patients showed implant/bone interface failure with screw pullout, probably through the effect of PMMA. In contrast to the PJK cohort, six PJF patients all had varying degrees of neurologic deficits from modified Frankel grade C to D3, which recovered to grades D3 and to grade D2 in three patients each, after a revision operation of proximal extension of instrumented fusion with or without neural decompression. None of the possible demographic and radiologic risk factors showed statistical differences between the non-PJK/PJF, PJK, and PJF groups. Conclusions: Compared with the traditional open surgical approach used in the previous studies with a positive result for the prophylactic two-level cement augmentation, the MIS procedures with substantial benefits to patients in terms of less access-related morbidity and less blood loss also provide a greater segmental stability, which, however, may have a negative effect on the development of PJK/PJF.

Application of a Magnetic Resonance Imaging-Based Lumbar Vertebral Bone Quality Scoring System in Patients with Degenerative Lumbar Scoliosis

BACKGROUND

Although dual-energy X-ray absorptiometry is still the gold standard for diagnosing osteoporosis, it can lead to inaccurate bone mineral density measurements due to lumbar degeneration and scoliosis. Many researchers have investigated diagnostic methods for osteoporosis in patients with degenerative lumbar scoliosis (DLS). This study aimed to investigate the differences between conventional vertebral bone quality (VBQ) scores and modified VBQ scores in patients with DLS and the influence of lumbar scoliosis on VBQ scores.

METHODS

We retrospectively collected the clinical and radiological data of 68 patients with DLS admitted to Sun Yat-sen Memorial Hospital from July 2018 to April 2023. The patients were classified into one of 2 groups based on the T score of the left femoral neck. VBQ scores relative to cerebrospinal fluid at different levels, VBQ scores on different planes and single-level VBQ scores were compared. Receiver operating characteristic analysis was also performed. Different modified VBQ scores were compared between the moderate scoliosis group (10°

RESULTS

There were no significant differences in VBQ scores relative to cerebrospinal fluid at different levels (P = 0.983), on different planes (P = 0.832) or at single-level (P = 0.996). All the VBQ scores were negatively correlated with the T score of the left femoral neck. There were no significant differences in the modified VBQ scores between the moderate and severe scoliosis groups.

CONCLUSIONS

Different modified VBQ scores can be used as supplementary methods for diagnosing osteoporosis in patients with DLS. Lumbar scoliosis may not significantly affect the VBQ score.

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Key Words

• Bone mineral density
• Degenerative lumbar scoliosis
• Magnetic resonance imaging
• Osteoporosis
• Vertebral bone quality score

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MESH Headings

• Humans
• Scoliosis/diagnostic imaging
• Female
• Lumbar Vertebrae/diagnostic imaging
• Male
• Aged
• Retrospective Studies
• Middle Aged
• Magnetic Resonance Imaging/methods
• Bone Density
• Absorptiometry, Photon/methods
• Osteoporosis/diagnostic imaging
• Osteoporosis/complications
• Aged, 80 and over

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Affiliation(s)

Wanli Zheng Department of Spine Surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China; Department of Spine Surgery, The Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
Weitao Han Department of Spine Surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
Song Jin Department of Spine Surgery, The Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
Mingxi Zhu Department of Spine Surgery, The Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
Zhengqi Huang Department of Spine Surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
Tianyu Qin Department of Spine Surgery, The Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
Ming Shi Department of Spine Surgery, The Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
Bo Gao Department of Spine Surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
Wei Ye Department of Spine Surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.

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Decisional regret following corrective adult spinal deformity surgery: a single institution study of incidence and risk factors

PURPOSE

To assess the characteristics and risk factors for decisional regret following corrective adult spinal deformity (ASD) surgery at our hospital.

METHODS

This is a retrospective cohort study of a single-surgeon ASD database. Adult patients (> 40 years) who underwent ASD surgery from May 2016 to December 2020 with minimum 2-year follow-up were included (posterior-only, ≥ 4 levels fused to the pelvis) (n = 120). Ottawa decision regret questionnaires, a validated and reliable 5-item Likert scale, were sent to patients postoperatively. Regret scores were defined as (1) low regret: 0-39 (2) medium to high regret: 40-100. Risk factors for medium or high decisional regret were identified using multivariate models.

RESULTS

Ninety patients were successfully contacted and 77 patients consented to participate. Nonparticipants were older, had a higher incidence of anxiety, and higher ASA class. There were 7 patients that reported medium or high decisional regret (9%). Ninety percentage of patients believed that surgery was the right decision, 86% believed that surgery was a wise choice, and 87% would do it again. 8% of patients regretted the surgery and 14% believed that surgery did them harm. 88% of patients felt better after surgery. On multivariate analysis, revision fusion surgery was independently associated with an increased risk of medium or high decisional regret (adjusted odds ratio: 6.000, 95% confidence interval: 1.074-33.534, p = 0.041).

CONCLUSIONS

At our institution, we found a 9% incidence of decisional regret. Revision fusion was associated with increased decisional regret. Estimates for decisional regret should be based on single-institution experiences given differences in patient populations.

MRI Vertebral Bone Quality Correlates With Interbody Cage Subsidence After Anterior Cervical Discectomy and Fusion

STUDY DESIGN

Retrospective observational study of consecutive patients.

OBJECTIVE

The purpose of the study was to evaluate VBQ as a predictor of interbody subsidence and to determine threshold values that portend increased risk of subsidence.

SUMMARY OF BACKGROUND DATA

Many risk factors have been reported for the subsidence of interbody cages in anterior cervical discectomy and fusion (ACDF). MRI Vertebral Bone Quality (VQB) is a relatively new radiographic parameter that can be easily obtained from preoperative MRI and has been shown to correlate with measurements of bone density such as DXA and CT Hounsfield Units.

METHODS

All patients who underwent 1- to 3-level ACDF using titanium interbodies with anterior plating between the years 2018 and 2020 at our tertiary referral center were included. Subsidence measurements were performed by 2 independent reviewers on CT scans obtained 6 months postoperatively. VBQ was measured on pre-operative sagittal T1 MRI by 2 independent reviewers, and values were averaged.

RESULTS

Eight-five fusion levels in 44 patients were included in the study. There were 32 levels (38%) with moderate subsidence and 12 levels with severe subsidence (14%). The average VBQ score in those patients with severe subsidence was significantly higher than those without subsidence (3.80 vs. 2.40, P<0.01). A threshold value of 3.2 was determined to be optimal for predicting subsidence (AUC=0.99) and had a sensitivity of 100% and a specificity of 94.1% in predicting subsidence.

CONCLUSIONS

VBQ strongly correlates with the subsidence of interbody grafts after ACDF. A threshold VBQ score value of 3.2 has excellent sensitivity and specificity for predicting subsidence. Spine surgeons can use VBQ as a readily available screening tool to identify patients at higher risk for subsidence.

LEVEL OF EVIDENCE

Level-IV.

Simplified S1 vertebral bone quality score independently predicts proximal junctional kyphosis after surgery for degenerative lumbar scoliosis

OBJECTIVE

Our study aimed to assess the effectiveness of the simplified S1 vertebral bone quality (VBQ) score in predicting the incidence of proximal junctional kyphosis (PJK) after surgery for degenerative lumbar scoliosis (DLS).

METHODS

We reviewed 122 patients with DLS who underwent posterior lumbar decompression and long-segment fusion surgery in our hospital from January 2016 to December 2020. The patients were classified into PJK group and non-PJK group. S1 VBQ scores are determined by signal intensity measurements taken from the mid-sagittal plane of T1-weighted non-contrast MRI. Logistic regression analysis was used to identify factors associated with PJK. Receiver-operating characteristic curve (ROC) analysis was used to evaluate the value of S1 VBQ score in predicting pedicle PJK after DLS.

RESULTS

122 DLS patients (90 females and 32 males) met the inclusion criteria. In addition, 27 patients (22.13%) had PJK at the time of last follow-up. VBQ was higher in PJK patients than non-PJK patients (3.58 ± 0.67 vs. 3.08 ± 0.54, p < 0.001). Preoperatively, patients in the PJK group had a greater TLK than those in the non-PJK group (20.00 ± 6.22 vs. 16.86 ± 5.38, p = 0.011). After surgery, patients in the PJK group had greater TLK (p < 0.001) and PJA (p < 0.001) compared with the non-PJK group. At final FU, patients in the PJK group had greater TK (p = 0.002), TLK (p < 0.001), SVA (p < 0.001), and PJA (p < 0.001) than patients in the non-PJK group (Table 4). In multivariate logistic regression analysis, higher VBQ score (OR 4.565, 95% CI 1.43-14.568, p = 0.010), advanced age (OR 1.119, 95% CI 1.021-1.227, p = 0.016), and larger TLK (OR 1.191, 95% CI 1.041-1.362, p = 0.011) were significant predictors of postoperative PJK in patients with DLS (Table 6). A statistically significant positive correlation existed between VBQ score and PJA change (r = 0.370, p < 0.001). We created ROC curves for VBQ scores as predictors of PJK with a diagnostic accuracy of 72.1% (95% CI 60.15-82.9%.The ideal limit for the VBQ score was 3.205 (sensitivity: 77.8%, specificity: 81.4%).

CONCLUSION

To the best of our knowledge, this is the first study to evaluate the effectiveness of the S1 VBQ score in predicting postoperative PJK in DLS. Our study included major risk factors and found that S1 VBQ score was a significant predictor of PJK in patients undergoing DLS surgery. The higher the S1 VBQ score, the higher the probability of PJK.

Comparative Analysis of the 3 Cervical Vertebral Bone Quality (C-VBQ) Score Methodologies and Their Correlations to the Lumbar Vertebral Bone Quality (VBQ) Score

OBJECTIVE

Common complications after spinal fusion, such as pseudoarthrosis, cage subsidence, or instrumentation failure, are affected by patients' bone quality. The cervical-vertebral bone quality (C-VBQ) score, a magnetic resonance imaging (MRI)-based adaption of the lumbar vertebral bone quality (VBQ) score, was developed by 3 separate research groups simultaneously to evaluate bone quality in cervical spinal fusion patients. We present the first analysis comparing these scoring methods to the well-validated VBQ score.

METHODS

A retrospective analysis of data for consecutive patients who underwent spine surgery at a single institution was completed. The VBQ score was calculated using the Ehresman et al.

METHOD

The C-VBQ scores, named according to placement of the region of interest within the cerebral spinal fluid, were calculated separately using the methods of Soliman et al. (C2-VBQ), Razzouk et al. (C5-VBQ), and Huang et al. (T1-VBQ). Linear regression models were utilized to evaluate correlations to the VBQ score.

RESULTS

A total of 105 patients were identified (mean age, 57.0 ± 11.9 years; women, 50.5%). Mean scores were C2-VBQ, 2.37 ± 0.55; C5-VBQ, 2.36 ± 0.61; and T1-VBQ, 2.64 ± 0.68. The C-VBQ scores for the C2 level were significantly higher than those for the C3-C6 levels (3.18 ± 0.96 vs. 2.63 ± 0.77, P < 0.001), whereas the C7 level was found to have significantly lower C-VBQ scores (2.42 ± 0.78 vs. 2.63 ± 0.77, P = 0.04). The C2-VBQ (r = 0.63) score had the strongest correlation to the VBQ score, compared to C5-VBQ (r = 0.41) and T1-VBQ (r = 0.43) (P < 0.001).

CONCLUSIONS

This study demonstrates that the C2-VBQ had the strongest correlation to the lumbar VBQ score among all C-VBQ scores.

Cervical Vertebral Bone Quality Score Independently Predicts Distal Junctional Kyphosis After Posterior Cervical Fusion

BACKGROUND AND OBJECTIVE

Posterior cervical fusion is the surgery of choice when fusing long segments of the cervical spine. However, because of the limited presence of this pathology, there is a paucity of data in the literature about the postoperative complications of distal junctional kyphosis (DJK). We aimed to identify and report potential associations between the preoperative cervical vertebral bone quality (C-VBQ) score and the occurrence of DJK after posterior cervical fusion.

METHODS

The authors retrospectively reviewed records of patients who underwent posterior cervical fusion at a single hospital between June 1, 2010, and May 31, 2020. Patient data were screened to include patients who were >18 years old, had baseline MRI, had baseline standing cervical X-ray, had immediate postoperative standing cervical X-ray, and had clinical and radiographic follow-ups of >1 year, including a standing cervical X-ray at least 1 year postoperatively. Univariate analysis was completed between DJK and non-DJK groups, with multivariate regression completed for relevant clinical variables. Simple linear regression was completed to analyze correlation between the C-VBQ score and total degrees of kyphosis angle change.

RESULTS

Ninety-three patients were identified, of whom 19 (20.4%) had DJK and 74 (79.6%) did not. The DJK group had a significantly higher C-VBQ score than the non-DJK group (2.97 ± 0.40 vs 2.26 ± 0.46; P < .001). A significant, positive correlation was found between the C-VBQ score and the total degrees of kyphosis angle change (r 2 = 0.26; P < .001). On multivariate analysis, the C-VBQ score independently predicted DJK (odds ratio, 1.46; 95% CI, 1.27-1.67; P < .001).

CONCLUSION

We found that the C-VBQ score was an independent predictive factor of DJK after posterior cervical fusion.

Vertebral bone quality score as a novel predictor of proximal junctional kyphosis after thoracic adolescent idiopathic scoliosis surgery

INTRODUCTION

Proximal junctional kyphosis (PJK) is one of the most common complications after thoracic AIS surgery. Previous studies reported that the etiology of PJK was associated with osteopenia and meanwhile the AIS patients were found osteopenia which could persist into adulthood. Recently, an MRI-based vertebral bone quality score (VBQ) was reported to be a promising tool which can assess preoperative bone quality.

OBJECTIVE

This study aims to evaluate the utility of VBQ score in predicting PJK after corrective surgery for thoracic AIS (Lenke 1 and 2).

METHODS

We conducted a retrospective study to identify the predictive efficiency of VBQ score for PJK in thoracic AIS patients. Demographic, radiographic parameters, and surgical variables were collected. VBQ score was calculated using preoperative T1-weighted MRI. Univariate analysis, linear regression, and multivariate logistic regression were performed to determine potential risk factors of PJK and correlation between other parameters and VBQ score. Receiver operating characteristic analysis and area under the curve values were utilized to evaluate the predictive efficiency of VBQ score for PJK.

RESULTS

A total of 206 patients (aged 14.4 ± 2.3 years) were included, of which 33 (16.0%) developed PJK. VBQ scores were significantly different between the PJK and non-PJK groups (2.8 ± 0.2 vs 2.5 ± 0.2, P < 0.01). A significant positive correlation was found between VBQ score and PJA (R2 = 0.1728, P < 0.01).On multivariate analysis, VBQ score was the only significant predictor of PJK (odds ratio = 2.178, 95% CI = 1.644-2.885, P < 0.001), with a predictive accuracy of 83%.

CONCLUSION

Higher VBQ scores were independently associated with PJK occurrence after corrective surgery for thoracic AIS. Preoperative measurement of VBQ score on MRI may serve as a valuable tool in planning thoracic AIS surgery.

MRI-based Vertebral Bone Quality Score for Osteoporosis Screening Based on Different Osteoporotic Diagnostic Criteria Using DXA and QCT

In this study, we aim to evaluate the correlation between T score measured by dual X-ray absorptiometry (DXA), volumetric bone mineral density (vBMD) derived from quantitative computed tomography (QCT) and MRI-based vertebral bone quality (VBQ), explore the diagnostic performance of VBQ in osteoporosis and determine the recognition value of VBQ in osteoporotic fracture in a relatively large cohort of elderly patients scheduled to undergo spinal surgery. A total of 260 patients were enrolled in the study. DXA and QCT were used to evaluate osteoporotic status. We calculated the lumbar VBQ score, analyzed the correlation between T score, vBMD and VBQ, and explored whether VBQ was an influential factor of bone quality and fracture by binary logistic regression as well as the diagnostic performance of VBQ in osteoporosis and fracture by ROC curve. VBQ was negatively correlated with vBMD and T score. (r = - 0.487 vs. r = - 0.220). The VBQ score was a risk factor for osteoporosis under the QCT diagnostic criteria (OR = 2.245, 95% CI 1.456-3.460) and osteoporotic fractures (OR = 1.496, 95% CI 1.097-2.040). It exhibited superior discriminant performance for osteoporosis diagnosed by QCT, with a cutoff value of 3.70 and an AUC of 0.7354. Its cutoff value for osteoporotic fractures was 3.72, and its AUC was 0.6717. In a cohort of elderly patients scheduled to undergo spinal surgery, the VBQ score was more strongly associated with vBMD than the T score and could identify patients with osteoporosis and corresponding vertebral compression fracture (VCF).

Proximal Junctional Failure in Adult Spinal Deformity Surgery: An In-depth Review

Adult spinal deformity (ASD) surgery aims to correct abnormal spinal curvature in adults, leading to improved functionality and reduced pain. However, this surgery is associated with various complications, one of which is proximal junctional failure (PJF). PJF can have a significant impact on a patient's quality of life, necessitating a comprehensive understanding of its causes and the development of effective management strategies. This review aims to provide an in-depth understanding of PJF in ASD surgery. PJF is a complex complication resulting from a multitude of factors including patient characteristics, surgical techniques, and postoperative management. Age, osteoporosis, overcorrection of sagittal alignment, and poor bone quality are identified as significant risk factors. The clinical implications of PJF are substantial, often requiring revision surgery and causing a considerable decrease in patients' quality of life. Prevention strategies include careful preoperative planning, appropriate patient selection, and optimization of surgical techniques. Treatment often necessitates a multifaceted approach, including surgical intervention and the management of underlying risk factors. Predictive modeling is an emerging field that may offer a promising avenue for the risk stratification of patients and individualized preventive strategies. A thorough understanding of PJF's pathogenesis, risk factors, and clinical implications is essential for surgeons involved in ASD surgery. Current preventive measures and treatment strategies aim to mitigate the risk and manage the complications of PJF, but the complication cannot be entirely prevented. Future research should focus on the development of more effective preventive and treatment strategies, and predictive models could be valuable in this pursuit.

Proximal Junctional Kyphosis or Failure After Adult Spinal Deformity Surgery - Review of Risk Factors and Its Prevention

Proximal junction kyphosis (PJK) is a common imaging finding after long-level fusion, and proximal junctional failure (PJF) is an aggravated form of the progressive disease spectrum of PJK. This includes vertebral fracture of upper instrumented vertebra (UIV) or UIV+1, instability between UIV and UIV+1, neurological deterioration requiring surgery. Many studies have reported on PJK and PJF after long segment instrumentation for adult spinal deformity (ASD). In particular, for spine deformity surgeons, risk factors and prevention strategies of PJK and PJF are very important to minimize reoperation. Therefore, this review aims to help reduce the occurrence of PJK and PJF by updating the latest contents of PJK and PJF by 2023, focusing on the risk factors and prevention strategies of PJK and PJF. We conducted a search on multiple database for articles published until February 2023 using the search keywords "proximal junctional kyphosis," "proximal junctional failure," "proximal junctional disease," and "adult spinal deformity." Finally, 103 papers were included in this study. Numerous factors have been suggested as potential risks for the development of PJK and PJF, including a high body mass index, inadequate postoperative sagittal balance and overcorrection, advanced age, pelvic instrumentation, and osteoporosis. Recently, with the increasing elderly population, sarcopenia has been emphasized. The quality and quantity of muscle in the surgical site have been suggested as new risk factor. Therefore, spine surgeon should understand the pathophysiology of PJK and PJF, as well as individual risk factors, in order to develop appropriate prevention strategies for each patient.