Spine最新文献

Study design: Retrospective Comparative Study.

Objective: A comparative analysis was aimed at evaluating the clinical and radiologic outcomes of cases managed with versus without ACR.

Summary of background data: Management of spinal tuberculosis (STB) is accomplished with or without anterior column reconstruction (ACR). However, no objective criterion has been defined citing absolute indication.

Methods: A retrospective analysis of prospectively collected data of STB was carried out with a minimum follow-up of one year. Along with basic demography, radiologic parameters like vertebral body height loss (VHL), column height loss (CHL), segmental kyphosis (SK), and adjusted kyphosis (AK) were calculated. A ROC curve analysis was done to identify cutoff values, followed by subgroup analysis for each parameter.

Results: In total 103 patients (60 female, 43 male), 55 cases were managed operatively and ACR was done in 39 of those. Change in ODI, VHL, and kyphosis correction were significantly better in ACR ( P <0.01). ROC analysis identified cutoff values for VHL 0.55 (sensitivity 0.87, 1-specificity 0.37), CHL 1.12 (sensitivity 0.76, 1-specificity 0.25), and AK 15° (sensitivity 0.74, 1-specificity 0.43). Subgroup analysis was carried out in operated patients segregated above these cutoff values. Though vertebral height gain was better with ACR, no significant differences across the change in ODI and loss of correction were noted between ACR and N-ACR. However, the instruments to disease vertebrae (I/D) ratio was significantly different across all subgroups ( P <0.05).

Conclusion: A similar functional outcome, kyphosis correction, and mechanical stability (loss of correction) can be achieved without ACR if index screw purchase with increasing the implant density is feasible. In cases where the index screw deems impossible, the objective criteria of VHL>0.55, CHL>1.1, AK>15 degrees should be considered for deciding the need for anterior column reconstruction to achieve better outcomes.

Level of evidence: Level III.

Study design: Retrospective study.

Objective: To investigate the association between postoperative orientation of the L1 vertebra and proximal junctional kyphosis (PJK) occurrence in adult spinal deformity (ASD) surgery.

Summary of background data: PJK remains a common complication, with various risk factors identified. However, the role of the orientation of L1 vertebra has not been well studied.

Materials and methods: A total of 312 patients who underwent fusion from the pelvis to the lower thoracic spine (T9-12) were analyzed. Patient, surgical, and radiographic variables were evaluated for risk factor analysis of PJK. L1 tilt and L1 slope at six weeks postoperatively were included to represent the L1 orientation. Multivariate logistic regression analysis was performed to identify risk factors for PJK. Receiver operating characteristics (ROC) curve analysis was used to calculate the cutoff value of predictors for PJK.

Results: PJK developed in 109 patients (34.9%). Multivariate regression analysis identified postoperative L1 tilt as the only independent risk factor for PJK (odds ratio=1.173, P <0.001). The cutoff value of L1 tilt for predicting PJK was determined as 8.1° based on ROC curve analysis (area under the curve=0.736, P <0.001). The rates of PJK (50.7% vs. 22.1%, P <0.001) and revision surgery (17.1% vs. 5.2%, P <0.001) were significantly higher in the high L1 tilt group than in the low L1 tilt group. The high L1 tilt group also exhibited significantly greater pelvic tilt, thoracic kyphosis, and T1 pelvic angle, as well as worse clinical outcomes at two years compared with the low L1 tilt group.

Conclusions: An L1 tilt >8.1° was associated with a higher risk of PJK, suboptimal sagittal alignment, and worse clinical outcomes at two years. Therefore, optimizing L1 orientation may reduce PJK risk and improve long-term surgical outcomes.

Study design: A combined clinical and cadaveric observational study.

Objectives: To investigate whether anatomic variations in the lumbosacral plexus (LSP) are associated with diagnostic discrepancies in lumbar disc herniation (LDH) and to corroborate clinical findings with anatomic evidence.

Summary of background data: LDH is typically diagnosed based on clinical neurological symptoms and the level of the compressed spinal nerve root (the responsible lesion) identified by magnetic resonance imaging. However, in some patients, radiculopathy symptoms do not always align with the responsible lesion, complicating the diagnosis. This discrepancy may be linked to anatomic variations in the LSP, although the exact cause remains unclear. LSP roots may exhibit cranio-caudal deviations, which tend to be associated with shorter or longer 12th ribs, providing a potential basis for investigation.

Methods: We examined 12th rib length in 144 patients with LDH at Juntendo University Hospital and investigated the relationship between LSP branch deviations and 12th rib length in 29 Japanese cadavers, donated to Juntendo University School of Medicine.

Results: Of the total, 102 cases showed matching radiculopathies and responsible lesions (matched group), whereas 42 cases exhibited discrepancies (mismatched group). The mismatched group was subdivided into: 19 cases with radiculopathy at a lower level than predicted by the responsible lesion (lower-level radiculopathy type) and 23 cases with radiculopathy at a higher level (higher-level radiculopathy). These types were significantly associated with shorter and longer 12th ribs, respectively, suggesting cranial and caudal deviations in LSP branches, confirmed by anatomic examination.

Conclusion: These findings suggest that contradictory neurological symptoms in LDH may be largely due to cranio-caudal deviations in the LSP and its branches. Furthermore, the 12th rib length may help predict these anatomic variations, potentially improving diagnostic accuracy in LDH.

Study design: Retrospective cohort from a multicenter registry.

Objective: Characterize the variability of the last substantially touched vertebra (LSTV) in Lenke 1- and 2-AR curves and evaluate whether clinical or radiographic factors permit fusion short of the LSTV without increased adding-on risk.

Summary of background data: Lenke 1 and 2A curves with an R modifier based on L4 tilt in adolescent idiopathic scoliosis (AIS) are associated with a higher risk of adding-on after posterior spinal fusion (PSF). Fusion to the LSTV may reduce this risk but often requires extending into the distal lumbar spine, compromising motion. The safety of terminating fusion proximal to the LSTV in select patients, without increasing adding-on risk, remains uncertain.

Methods: Patients with Lenke 1- or 2-AR curves undergoing PSF with minimum 2-year follow-up were identified. Radiographs were reviewed to determine LSTV level and assess for adding-on. Patients were stratified based on whether the lowest instrumented vertebra (LIV) was proximal to or at the level of/distal to the LSTV. Among those fused proximal, univariate and multivariate analyses were used to identify protective factors. Subgroup analyses were performed by LSTV level.

Results: Of 324 patients, 144 (44.4%) were instrumented proximal to the LSTV. Adding-on occurred in 16.0% of all patients, more frequently in short fusions (21.5% vs. 11.7%, P=0.016). Multivariate analysis identified higher Risser (OR=1.62, P=0.006) and greater main thoracic correction (OR=1.09, P<0.001) as protective. Adding-on was rare (4.0%) when the LSTV was L4, even when fused short.

Conclusions: In skeletally mature patients with adequate thoracic correction, fusion proximal to the LSTV in Lenke 1- and 2-AR curves may be performed safely. When the LSTV is L4, fusion to that level may be unnecessary, offering an opportunity for lumbar motion preservation without increased risk of adding-on.

Level of evidence: IV.

Study design: Retrospective cohort study.

Objective: To develop machine learning (ML) models integrating clinical/imaging variables for predicting three-month and six-month outcomes of radiofrequency (RF) treatment in lumbar facetogenic pain, and an independent temporal validation cohort was used to evaluate the model's performance. Shapley additive explanations (SHAP) analysis was utilized to identify key variables and construct a simplified model.

Summary of background data: Early identification of RF-responsive patients remains challenging, with limited noninvasive prognostic tools available.

Materials and methods: Six ML models were trained using 17 clinical/imaging variables from 372 RF-treated patients. Model performance was evaluated through AUROC, with SHAP analysis identifying key variables. Simplified models using clinical-only, imaging-only, and SHAP-selected variables were compared.

Results: In the discovery (n=312) and temporal validation (n=60) cohorts, 141 and 26 patients had unsuccessful three-month outcomes, respectively. The logistic model outperformed others, achieving AUROCs of 0.834 (95% CI: 0.725-0.942) and 0.818 (0.713-0.923) for three-month prediction in discovery and validation cohorts. Simplified models showed comparable performance (discovery AUROC: 0.795-0.837; validation: 0.699-0.814). Six-month predictions demonstrated similar robustness (discovery AUROC: 0.813; validation: 0.783). Decision curve analysis confirmed the logistic model's clinical utility, providing net benefits at threshold probabilities >40%.

Conclusions: The Logistic model, which is based on clinical and imaging variables, has the potential to facilitate early screening of patients who might benefit from RF treatment in the short term and long term. SHAP analysis helps evaluate the impact of variables and build simplified models with comparable performance. The key variables identified in this study require further verification through external geographic validations.

Level of evidence: Level III.

Study design: A retrospective analysis.

Objective: The aim of this study was to identify a robust radiomic signature from deep learning segmentations for intervertebral disc (IVD) degeneration classification.

Summary of data: Low back pain (LBP) is the most common musculoskeletal symptom worldwide and IVD degeneration is an important contributing factor. To improve the quantitative phenotyping of IVD degeneration from T2-weighted magnetic resonance imaging (MRI) and better understand its relationship with LBP, multiple shape and intensity features have been investigated. IVD radiomics has been less studied but could reveal subvisual imaging characteristics of IVD degeneration.

Materials and methods: We used data from Northern Finland Birth Cohort 1966 members who underwent lumbar spine T2-weighted MRI scans at age 45 to 47 (n=1397). We used a deep learning model to segment the lumbar spine IVDs and extracted 737 radiomic features, as well as calculating IVD height index and peak signal intensity difference. Intraclass correlation coefficients across image and mask perturbations were calculated to identify robust features. Sparse partial least squares discriminant analysis was used to train a Pfirrmann grade classification model.

Results: The radiomics model had balanced accuracy of 76.7% (73.1%-80.3%) and Cohen's kappa of 0.70 (0.67-0.74), compared with 66.0% (62.0%-69.9%) and 0.55 (0.51-0.59) for an IVD height index and peak signal intensity model. 2D sphericity and interquartile range emerged as radiomics-based features that were robust and highly correlated to Pfirrmann grade (Spearman's correlation coefficients of -0.72 and -0.77, respectively).

Conclusion: Based on our findings, these radiomic signatures could serve as alternatives to the conventional indices, representing a significant advance in the automated quantitative phenotyping of IVD degeneration from standard-of-care MRI.

Study design: Delphi consensus.

Objective: To define an optimal surgical composite outcome measure in patients with metastatic spine disease (OSCO-M) through international consensus among key opinion leaders.

Materials and methods: Members of the AO Spine Knowledge Forum Tumor, an international group of dedicated spine oncology surgeons and oncologists, participated in a modified Delphi process between March 2023 and November 2024. The study was conducted in 2 parts. The first part aimed on identifying which outcome variables were deemed important to be included in the composite outcome. The second part focused on the definition of a successful outcome with regards to the agreed variables from Part 1. Each part consisted of a questionnaire and a consensus meeting. Consensus was achieved when a threshold of 70% agreement was reached.

Results: A total of 42 dedicated spine oncology surgeons and oncologists from North America, Latin America, Europe, and Asia participated. Over 87% of respondents agreed that composite measures reflect the multidimensional aspect of the surgical process more than an individual outcome variable. Most respondents (93%) agreed/strongly agreed that composite measures should be used to assess the quality of surgical care in spine oncology. Through consensus, the following three outcome variables were selected to define the OSCO-M: the absence of SAVES-V2 (Spinal Adverse Events Severity System, Version 2) grade 3 adverse events or higher within 30 days of surgery, maintaining or improving ECOG (Eastern Cooperative Oncology Group) performance status at 90 days, and being ambulatory (with or without aid) at 90 days.

Conclusion: This is the first study defining a composite outcome measure in oncologic surgery for spinal metastases derived from an international group of key opinion leaders in spine oncology. The OSCO-M may be useful for future research in spine tumor patients and serve as a benchmark to optimize outcomes.

Study design: Retrospective Cost-Analysis Study.

Objective: The primary aim of this study was to determine the cost-effectiveness from a public payer's perspective between RAN, NAV, and FH.

Background: Robotic-assisted navigation (RAN) and image-guided intraoperative navigation (NAV) are associated with higher pedicle screw placement accuracy and lower complication rates than freehand (FH) technique to treat idiopathic scoliosis. However, RAN and NAV are underutilized and payer coverage remains limited.

Methods: A Markov decision-analysis model for a cost-utility analysis of FH/NAV/RAN for patients with IS was created, and a probability sensitivity analysis was performed. Probabilities of health states, associated reimbursement costs, and quality-adjusted life years (QALYs) were estimated from literature. For each technique, incremental cost-utility ratio (ICURs), net costs, incremental net monetary benefit, net monetary benefit, and QALYs were calculated. Cost-effectiveness acceptability (CEA) curve analysis was performed by varying WTPT between $10,000 to $250,000. Deterministic sensitivity analysis (DSA) was performed by varying probabilities, QALYs, and costs. For cost-effective treatment strategies, cost savings to payers, if present, were calculated over a 7-year horizon.

Results: When compared to FH technique, the ICUR of RAN ($10,672/QALY) and NAV (-$108,831/QALY) were below the societal willingness-to-pay threshold (WTPT) of $50,000. RAN was not more cost-effective than NAV (ICUR: $255,518/QALY) at a WTPT of $50,000. However, CEA demonstrated that RAN was the most cost-effective strategy for all WTPTs above $50,000. The mean cost of NAV per patient was lower than FH by $3610 (95% CI: $3419 - $3801; P < 0.001). Mean cost of RAN per patient was higher than FH by $527 (95% CI: $267 - $786; P < 0.001) and NAV by $4137 (95% CI: $3953 - 4320; P < 0.001). DSA demonstrated sensitivity to < 25% of variables.

Conclusion: NAV and RAN are both more cost-effective than FH. NAV can save payers $45 million over 7 years. Payers should consider increasing reimbursement coverage for NAV and RAN.

Level of evidence: Level III.

Study design: Systematic review.

Objective: To determine the incidence of inappropriate or uncertain implementation of the minimally important clinical difference (MCID) for the neck disability index (NDI).

Summary of background data: The NDI consists of 10 items that yield a total score out of 50, but some users double the scale to report total scores out of 100. The most used MCID for the NDI is 7.5 out of 50. Implementation of the MCID can be problematic if users are not attentive to the scale of the NDI.

Methods: We performed a methodological review of studies that cited the MCID for the NDI. We defined appropriate implementation as the congruent magnitude of the scales used for NDI data and the MCID. We evaluated study characteristics associated with appropriate implementation using multivariable logistic regression.

Results: Among 163 included studies, twenty (12%) reported a 0 to 50 scale for the NDI, 66 (40%) reported a 0 to 100 scale, and the remaining 77 (47%) did not report which scale was used. Fifty-seven (35%) reported an MCID of 7.5, 37 (23%) reported an MCID of 15, and the remaining 69 (42%) did not report which value of the MCID used. Appropriate implementation of the MCID occurred in 39 studies (24%), whereas implementation was inappropriate in 16 (10%) and uncertain due to poor reporting in 108 (66%). Studies published more recently (OR 1.20 per yr, 95% CI 1.02-1.40, P =0.03) and studies that were RCTs (OR 4.85, 95% CI 1.25-18.79, P =0.02) had greater odds of being associated with appropriate implementation.

Conclusions: Inappropriate implementation of the MCID for the NDI is problematic and occurs often, and uncertain implementation due to poor reporting is also common. Evidence users should be cautious when interpreting studies that implement the NDI, and should consider whether the magnitude of the scales used for the NDI and the MCID are congruent.

Study design: Cadaveric biomechanics study.

Objective: This study compares five C2 fixation methods: pedicle, pars, translaminar, medial in-out-in, and subfacetal screws.

Summary of background data: Variations in vascular and pedicle anatomy of the C2 vertebra can make C2 fixation difficult. Two novel trajectories-the medial in-out-in and subfacetal trajectory-may be alternatives. The medial in-out-in trajectory enables three-point cortical fixation while the subfacetal trajectory avoids the VA.

Materials and methods: Polyaxial screws were inserted into C1 lateral masses and C2 vertebrae in 12 cadaveric specimens. Specimens were assigned to one of four test groups based on C2 screw trajectory: pedicle, pars, medial in-out-in, subfacetal, and translaminar. Range of motion (ROM) in flexion/extension (FE), lateral bending (LB), and axial rotation (AR) were measured at C1-2 using a custom-built six-degree-of-freedom motion simulator and motion analysis software. Two ROM tests were performed on each specimen: (1) intact construct and (2) screw-rod construct. C2 screws were then subjected to pullout testing.

Results: Average ROM for intact constructs was 11.04° in FE, 3.21° in LB, and 59.43° in AR. There was a significant difference in ROM in all three directions ( P <.01) among constructs. For the screw-rod construct, average ROM decreased 87% in FE, 86% in LB, and 97% in AR compared with intact. A two-way mixed ANOVA showed there was no significant difference in ROM between test groups for FE ( P =0.738), LB ( P =0.714), or AR ( P =0.996) independent of construct. Medial in-out-in showed 10% higher pullout strength compared with the pedicle screw and subfacetal showed an 83% increase in pullout strength compared with the pars screw.

Conclusions: The medial in-out-in and subfacetal trajectories represent viable alternatives for C1-2 stabilization in anatomically constrained cases, such as a high-riding vertebral artery or a narrow C2 pedicle. These novel techniques may expand surgical options for achieving robust C2 fixation.