PURPOSE
Achieving target L1-pelvic-angle (L1PA) is heavily influenced by segmental lordosis changes during adult spinal deformity (ASD) surgery. Understanding the effect of changing each lordotic segmental level on L1PA will aid in preoperative planning and intraoperative alignment assessment in ASD. In patients undergoing ASD surgery, we aimed to evaluate the impact of segmental lordosis changes on postoperative L1PA.
METHODS
A retrospective cohort study (2009-24) was performed for ASD surgery patients. Inclusion criteria were: ≥5-level fusion and sagittal/coronal deformity. Primary exposure variable was change in segmental lordosis at each lumbar level. Primary outcome was the change in L1PA. Multivariable regression controlling for preoperative and change in segmental lordosis at each level was performed.
RESULTS
Of 180 patients (mean age:59 ± 19 years, 32% males), mean preoperative/postoperative L1PA were 14 ± 11° and 12 ± 9°, respectively. L1/2: Mean change in lordosis was 7 ± 6°. For a 10° increase in L1/2 lordosis, the L1PA increased by 0.33° (β = -0.03, p = 0.684). L2/3: Mean change in lordosis was 8 ± 8°. For a 10° increase in L2/3 lordosis, the L1PA decreased by 0.01° (β = 0.00, p = 0.991). L3/4: Mean change in lordosis was 9 ± 8°. For a 10° increase in L3/4 lordosis, the L1PA decreased by 1.05° (β = 0.10, p = 0.086). L4/5: Mean change in lordosis was 9 ± 8°. For a 10° increase in L4/5 lordosis, the L1PA decreased by 1.78° (β = 0.18, p = 0.001). L5/S1: Mean change in lordosis was 11 ± 12°. For a 10° increase in L5/S1 lordosis, the L1PA decreased by 1.41° (β = 0.14, p = 0.002).
CONCLUSION
Changes in segmental lordosis at the L4/5 level were associated with greatest decrease in L1PA following ASD surgery, followed by L5/S1 and L3/4. Changes at L5/S1 influenced the L1PA slightly less than L4/5. These findings suggest that focusing on adding lordosis at the L4/5 and L5/S1 level will result in the greatest improvement in L1PA.
Harsh Jain, A. Sarikonda, Tyler Zeoli et al.· European spine journal· 0 citations
Radiographic pedicle screw loosening (PSL) remains a frequent postoperative finding and potential marker of screw-bone interface compromise after degenerative lumbar fusion, yet preoperative risk stratification remains inconsistent. This systematic review and meta-analysis aims to compare the association and discriminative performance of preoperative imaging-derived bone quality and paraspinal muscle metrics for predicting radiographic PSL after degenerative lumbar fusion.
PubMed, Embase, and CENTRAL were searched until January 2026. Observational studies reporting radiographic PSL and evaluating preoperative imaging-based bone or muscle metrics were included. Bone metrics comprised CT-derived Hounsfield units (HU), CT-derived bone mineral density (CT-BMD), MRI-based vertebral bone quality (VBQ), and DEXA T-scores. Muscle measures included psoas and posterior paraspinal cross-sectional area (CSA) and composition. Radiographic PSL definitions and adjudication modalities (plain radiograph versus CT) varied across included studies and were considered explicitly during synthesis and interpretation. Continuous outcomes were synthesized using random-effects inverse-variance models. Diagnostic accuracy was evaluated using bivariate (Reitsma) generalized linear mixed models, with summary receiver operating characteristic (SROC)-derived area under the curve (AUC) used to quantify discrimination. Risk of bias was assessed using QUADAS-2.
Twenty-nine studies (4711 patients; 25.4% PSL) were included. Patients with PSL demonstrated poorer preoperative bone quality across modalities, including lower HU (MD -24.7;
P
< 0.01), lower CT-BMD (MD -28.05;
P
< 0.05), lower DEXA T-scores (MD -0.18;
P
< 0.01), higher VBQ (MD 0.46;
P
< 0.01). Diagnostic discrimination was moderate and comparable across metrics (SROC-derived pooled AUC 0.71–0.76; meta-regression
P
= 0.08), although pooled estimates reflect a composite radiographic endpoint with heterogeneous adjudication conventions rather than a single uniform reference standard. Among muscle measures, reduced psoas CSA showed consistent association with PSL, whereas posterior paraspinal metrics were heterogeneous and largely non-significant. Nomogram analyses demonstrated clinically meaningful risk reclassification but limited rule-in and rule-out capacity.
Imaging-derived bone quality metrics identify substrate-level vulnerability to radiographic PSL and provide moderate preoperative discrimination. Because pooled discrimination reflects a composite radiographic endpoint rather than a uniform reference standard, these metrics are moderate risk stratifiers for radiographic PSL, not validated stand-alone tests for clinically meaningful construct failure. Limited and heterogeneous evidence suggests psoas size may represent a complementary frailty marker. Prospective validation and standardized thresholds are required.
Shaan Patel, S. Nischal, Lorenzo Ceccon et al.· Acta Neurochirurgica· 0 citations
STUDY DESIGN
Systematic review and meta-analysis.
OBJECTIVE
To identify patient-related, operative, radiographic, and bone quality predictive risk factors associated with proximal junctional failure (PJF) following adult spinal deformity (ASD) surgery and evaluate diagnostic performance of opportunistic CT-derived bone quality metrics.
SUMMARY OF BACKGROUND DATA
PJF is a severe complication of ASD correction associated with pain, deformity progression, and reoperation. While numerous risk factors have been proposed, reported associations are inconsistent, and clinical utility of opportunistic bone quality assessment remains uncertain.
METHODS
PubMed, Embase, and CENTRAL were searched from inception to January 2026. Observational studies reporting PJF after ASD surgery with extractable comparative data were included. Random-effects meta-analyses were used. Diagnostic accuracy of Hounsfield unit measurements was summarized using pooled sensitivity, specificity, and area under curve (AUC).
RESULTS
Twenty-eight studies encompassing 4560 patients were included, of whom 1064 (23.3%) developed PJF. Patients with PJF were older (MD 2.59 y, P <0.001) and had worse baseline disability and pain. Binary osteoporosis status was not consistently associated with PJF, though continuous bone measures were predictive, including lower DEXA T-scores (MD -0.55, P <0.001), and CT attenuation at upper instrumented vertebra (MD -28.97 units, P <0.0001) and immediately cranial adjacent vertebra (MD -32.67 units, P <0.0001). Radiographically, PJF was associated with greater preoperative sagittal misalignment, including higher pelvic tilt and sagittal vertical axis, lower lumbar lordosis, and greater pelvic incidence-lumbar lordosis mismatch. Fusion length and upper instrumented level (dichotomized at T10) were not significantly associated with failure. Hounsfield units demonstrated good diagnostic performance (pooled AUC 0.86).
CONCLUSION
PJF after ASD surgery reflects the interaction between sagittal misalignment, correction strategy, and junctional structural capacity. Continuous bone quality measures, particularly opportunistic Hounsfield unit assessment, show potential for risk stratification and may inform targeted preventive strategies in biologically vulnerable patients, pending prospective validation.
Shaan Patel, S. Nischal, Griffin W. White et al.· Spine· 0 citations
