Category: Deformity

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Spinal deformity surgery: interpreting the first two weeks of risk

Spine. 2026;51(20):E519-E529

The extent and complexity of deformity correction deserve explicit consideration when discussing perioperative risk. Katayanagi and colleagues identify associations between operative characteristics and complications during the first 14 days, but their registry does not establish that changing approach or staging surgery will independently prevent harm. Understanding the outcome definition is essential before applying its headline complication rate.

Study and key findings

This retrospective analysis used prospectively recorded Japanese registry data from 3,193 patients undergoing fusion of at least three vertebral segments between 2018 and 2022. Mean age was 60.8 years, and approximately three-quarters underwent fusion of six or more segments.

At least one complication occurred in 910 patients (28.5%); 812 (25.4%) had a major complication, and three died. Importantly, blood loss exceeding 1,000 ml was classified as a major complication and occurred in 638 patients (20.0%). Neurological complications occurred in 3.1%.

Adjusted odds of any complication were higher with operative duration exceeding five hours (odds ratio 4.40), three-column osteotomy (3.50), fusion exceeding five levels (1.51), and posterior/transforaminal interbody fusion (1.47). Staged surgery (0.24), lateral lumbar interbody fusion (0.74), and minimally invasive techniques (0.65) were associated with lower odds. Associations were broadly consistent in the long-fusion subgroup.

Interpretation and limitations

These findings support reviewing surgical burden and possible alternatives, not ranking techniques independently of indication. Prolonged surgery may reflect deformity complexity or intraoperative events; five hours is not a validated deadline for completing an operation.

The registry lacked radiographic deformity severity, achieved correction, patient-reported outcomes and several important comorbidities. Residual confounding therefore limits comparisons, particularly the apparently favorable association with staging. The bleeding-based definition substantially influences the composite endpoint, while overlapping major and minor events mean their percentages should not be added. Fourteen-day surveillance cannot characterize delayed infection, pseudarthrosis or later mechanical failure.

Clinical takeaway

Use these data to inform counseling and multidisciplinary planning around anticipated blood loss, fusion extent and osteotomy requirements. Consider staging or less invasive options when anatomically and clinically appropriate, while preserving necessary correction and decompression. Decisions require balancing early procedural burden against durable alignment and function, outcomes this study did not measure.

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Rethinking sagittal correction in adult spinal deformity

J Neurosurg Spine October 9, 2026

Choosing sagittal correction targets remains a central challenge in adult spinal deformity surgery.
This multicenter study evaluates lumbar alignment together with the relationship between T4 and L1.
It also examines how early junctional compensation can alter postoperative measurements.
The findings favor interpreting spinal shape in the context of fusion extent and caution against excessive correction.

Objective

Evaluate whether L1 pelvic angle (L1PA) and T4–L1 pelvic angle targets are associated with proximal junctional failure (PJF), accounting for early changes above the instrumented spine.

Methods

Retrospective analysis of a prospective multicenter adult deformity registry. Of 861 eligible patients, 661 had complete two-year follow-up and data. The principal comparisons involved 604 patients fused from the ilium to T2–4 (225 patients) or T9–11 (379 patients).

Six-week radiographs were assessed against published alignment targets. A virtual model estimated alignment without early proximal junctional compensation. PJF comprised proximal-extension revision or severe radiographic junctional kyphosis.

Main results

PJF occurred in 108/604 patients (17.9%); 50/604 (8.3%) underwent proximal-extension revision.

In upper-thoracic constructs, PJF rates were 25.6% with L1PA overcorrection, 12.9% within target, and 11.1% with undercorrection (P=0.029). This association persisted after demographic and comorbidity adjustment (P=0.028).

T4–L1 categories alone did not significantly distinguish failure rates in this subgroup (P=0.094).

In lower-thoracic constructs, removing simulated junctional compensation reclassified 175/379 patients (46.2%). The initial association between T4–L1 category and PJF then lost significance (P=0.148).

Interpretation

The most persuasive finding is that six-week alignment may already incorporate compensatory changes or evolving junctional failure. Consequently, a postoperative measurement can reflect both the surgical correction and the spine’s response to it.

The upper-thoracic findings raise concern about overcorrection relative to the studied L1PA formula. They do not establish intentional undercorrection as a superior treatment strategy. Evidence supporting particular combinations of lumbar and thoracic shape remains exploratory.

Limitations

Observational design limits causal inference, and only 76.8% of eligible patients contributed complete two-year data. Immediate postoperative radiographs were unavailable, requiring modeled reconstruction. Spinal flexibility was not directly measured, and patient-reported outcomes were not evaluated in this analysis.

Adjustment included age, sex, BMI and comorbidity burden, leaving potential residual confounding. Numerous authors disclosed industry relationships.

Clinical takeaway

Interpret L1PA and T4–L1 measurements alongside fusion extent and junctional behavior. The study supports caution with excessive lumbar correction and highlights the limitations of applying identical targets to upper- and lower-thoracic constructs.

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Domino connectors in adult spinal deformity: greater corrective capacity, but not proven clinical superiority

Journal of Neurosurgery: Spine 2026;45(4):516-526

Combined sagittal and coronal malalignment poses a particular challenge in adult spinal deformity surgery because correction must address both planes without concentrating excessive forces on individual fixation points. Vila and colleagues investigate the side-to-side domino connector as an active correction tool rather than simply a device for linking rods. Their multicenter cohort associates its use with greater correction and better maintained sagittal alignment at two years. However, comparable patient-reported outcomes and a higher rate of rod breakage/pseudarthrosis require a balanced interpretation: improved radiographic correction does not, by itself, establish greater clinical benefit or mechanical safety.

Objective

To compare radiographic correction, complications and patient-reported outcomes after adult spinal deformity surgery with or without a side-to-side domino connector used for correction of combined sagittal and coronal malalignment.

Methods

This retrospective analysis used a prospectively collected database from six European centers. It included 224 patients undergoing instrumented fusion to the pelvis with at least two years of follow-up: 81 with a domino connector and 143 without. Eligibility required a C7-to-central sacral vertical line distance greater than 20 mm together with sagittal malalignment defined by at least one of the study’s pelvic tilt, sagittal vertical axis, thoracic kyphosis or global tilt criteria.

Connector use was selected by the surgeon, often for more severe, rigid deformities. The connector group started with worse biplanar malalignment and underwent pedicle subtraction osteotomy more frequently. Propensity matching produced 69 pairs based on baseline global tilt, coronal displacement, osteotomy use and rod number. A separate analysis compared patients without pedicle subtraction osteotomy. Outcomes included standing radiographs, mechanical and neurological complications, unplanned reoperations, Oswestry Disability Index and Scoliosis Research Society-22 scores.

Main results

In the matched cohort, two-year global tilt was 24.6° with connectors versus 33.1° without, and L1-S1 lordosis was 54.8° versus 49.0°. Final coronal displacement did not differ significantly. In the full cohort, mechanical complications occurred in 41.9% of both groups, but the combined rod-breakage/pseudarthrosis category was higher with connectors: 22.2% versus 9.1% (P=.006). Unplanned reoperation rates were 27.2% versus 34.3%, without a significant difference. Two-year ODI and SRS-22 scores were comparable. Greater lumbar lordosis also persisted in the subgroup without pedicle subtraction osteotomy, although that comparison retained baseline imbalances.

Interpretation

The technical distinction is the intended force direction, referenced to trunk shift rather than simply curve concavity. For distraction-based correction, the authors place the connector on the side of coronal malalignment; for compression during asymmetric osteotomy closure, they place it opposite the shift. Their illustrated sequence establishes lumbopelvic fixation and initial correction through a contoured contralateral rod before connector-assisted adjustment. Intraoperative imaging checks coronal alignment against a pelvic reference. This is a useful framework for planning correction, but force distribution is a proposed mechanical rationale, not proof that the connector independently prevents fixation failure.

Limitations

This was not a randomized comparison, and matching cannot eliminate unmeasured confounding. Deformity rigidity, surgeon preferences, center-specific practice and the heterogeneity of control constructs may affect both correction and complications. Matching addressed selected variables rather than every baseline difference; thoracic kyphosis remained different between matched groups. The subgroup without pedicle subtraction osteotomy likewise does not isolate the device’s intrinsic effect from other corrective maneuvers.

The clearest persistent radiographic advantage was sagittal. Greater correction from a more displaced starting position should not be confused with significantly better final coronal balance. Similarly, comparable ODI and SRS-22 scores do not establish equivalence, but they do mean that superior patient-reported benefit was not demonstrated at two years.

An identical aggregate mechanical complication rate does not neutralize the higher rod-breakage/pseudarthrosis rate. Greater deformity severity and osteotomy use may contribute, but this study cannot establish their causal contribution or exclude a device-related contribution. The absence of reported intraoperative implant complications is also insufficient to establish general safety. The study received industry funding, and several authors disclosed relevant financial relationships. Longer follow-up and prospective comparative evaluation are needed to clarify durability and clinical benefit.

Clinical takeaway

A domino connector can be considered a correction adjunct when managing complex biplanar adult deformity, with its placement determined by the planned compression or distraction mechanism. This study supports its corrective potential, not routine use in every construct, replacement of an indicated osteotomy, or an expectation of better functional outcomes. Planning should retain equal attention to alignment, the lumbopelvic foundation and subsequent mechanical failure risk.

 

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Surgical Versus Nonoperative Treatment for Adult Spinal Deformity: A Multicenter Propensity Score–Matched Study of Two-Year Patient-Reported Outcomes

Spine 2026;51:1197–1208

Choosing between reconstruction and nonoperative care for adult spinal deformity demands a realistic estimate of benefit rather than radiographic enthusiasm alone. This multicenter analysis uses propensity matching to compare patients with similar measured baseline characteristics. At 2 years, surgery produced substantially greater improvement in disability and scoliosis-specific quality of life. Clinically meaningful benefit was achieved by a much larger proportion of surgical patients, although the cohort was relatively young and only mildly to moderately impaired at baseline. The results strengthen comparative-effectiveness evidence but do not replace individualized discussion of complications and residual confounding.

Objective

To compare 2-year patient-reported outcomes after surgical and nonoperative management of adult spinal deformity while reducing measured treatment-selection bias through propensity-score matching.

Methods

The retrospective comparison used prospectively collected data from an adult spinal-deformity registry at six centers. Of 580 eligible patients, 338 underwent surgery and 242 received nonoperative care. Propensity scores incorporated demographic variables, radiographic alignment measures and baseline Oswestry Disability Index (ODI) and Scoliosis Research Society–22 (SRS-22) scores. One-to-one matching produced 160 balanced pairs.

Main results

At 2 years, mean ODI improvement was −19.4 ± 14.2 points after surgery and −4.2 ± 12.3 with nonoperative care (p<0.001). A clinically meaningful ODI improvement of at least 15 points was achieved by 72% of surgical patients versus 29% of nonoperative patients.

The mean 2-year SRS-22 total score was 3.95 ± 0.67 after surgery and 3.46 ± 0.75 after nonoperative care (p<0.0001). The minimum clinically important difference for the SRS-22 total score was reached by 81.3% and 36.9%, respectively.

Interpretation

Among matched patients, reconstruction was associated with a large and clinically visible improvement beyond that observed with nonoperative management. Propensity matching makes the groups more comparable but cannot recreate randomization. The magnitude of benefit should therefore be presented alongside the patient’s operative risk, deformity phenotype, frailty, goals and probability of complications or revision.

Limitations

Treatment was not randomized, and unmeasured factors such as surgeon judgment, symptoms, patient preference and socioeconomic context may still influence both selection and outcome. The matched cohort had a mean age of about 45 years and mild-to-moderate baseline impairment, limiting extrapolation to older or frailer patients. Two-year follow-up does not capture late mechanical failure, revision burden or durability.

Clinical takeaway

For an appropriately selected adult with symptomatic deformity, surgery offers a substantially greater chance of meaningful 2-year improvement than continued nonoperative care. Use those probabilities in shared decision-making, but pair them with center-specific complication and revision estimates rather than presenting benefit in isolation.

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Use of pelvic incidence to predict proximal junctional failure in long-segment spinal fusion

J Neurosurg Spine 45:44–54, 2026

This clinical study evaluates how pelvic incidence (PI) affects spinopelvic correction and proximal junctional failure (PJF) after long-segment thoracolumbar fusion with pelvic fixation in 204 adult spinal deformity patients. Patients were stratified by PI (<55° vs >55°) and analyzed for radiographic outcomes, complications, and PROMs using frequentist and Bayesian models.

Key findings show lower PI independently predicts higher PJF risk (21% vs 9%), with lower thoracic UIV and revision surgery as additional predictors; lower PI patients more often met age-adjusted alignment goals but experienced greater overcorrection relative to individualized morphology.

Objective Evaluate how pelvic incidence (PI) affects spinopelvic correction and complication rates (especially proximal junctional pathology) after long-segment fusion for adult spinal deformity.

Cohort Retrospective analysis of 204 patients undergoing open posterior long-segment thoracolumbar fusion with pelvic fixation (≥ 6 levels) with ≥ 1-year follow-up; grouped by PI cutoff 55° into lower PI (n=108) vs higher PI (n=96).

Primary finding (PJF rates) Lower PI patients had higher proximal junctional failure (PJF) at 1 year than higher PI patients (21% vs 9%, p=0.019).

UIV subgroup With an upper thoracic UIV (T2–5), PJF was 15% in lower PI vs 0% in higher PI (p=0.014).

Independent predictors Multivariate analysis: lower PI (OR 4.3, p=0.006), lower thoracic UIV (T10–12) (OR 6.5, p=0.005), and revision surgery (OR 23.8, p=0.001) independently predicted PJF.

Model confirmation Bayesian mixed-effects modeling also identified lower PI (OR 6.25, posterior probability 0.996) and lower thoracic UIV (OR 7.03, posterior probability 0.997) as significant predictors of PJF.

PJK vs PJF Proximal junctional kyphosis (PJK) rates were similar between PI groups at 1 year (38% vs 41%, p=0.697), despite the PJF difference.

Planning implication Preoperative PI morphology may guide individualized surgical planning to reduce risk of junctional pathology, since lower PI carried higher PJF risk after long-segment fusion.

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Long-Term Clinical Benefits of Age-Adjusted Sagittal Correction in Adult Spinal Deformity Surgery

Neurosurgery 98:1040–1050, 2026

This study evaluates long-term clinical outcomes of age-adjusted sagittal alignment correction in adult spinal deformity (ASD) surgery by integrating PI–LL, pelvic tilt, T1 pelvic angle, and SVA. Using hierarchical cluster analysis on 386 patients with long-segment fusion, three postoperative alignment patterns emerged—undercorrected, matched, and overcorrected—correlated with differing radiographic trajectories and complication rates.

Patients in the matched-correction cluster achieved the best balance of clinical improvement (ODI and SRS-22r) and minimized proximal junctional kyphosis/failure, while overcorrection increased mechanical complications despite stronger radiographic correction. The results support a multi-parameter, age-adjusted strategy and propose cluster-derived offset ranges as practical surgical benchmarks.

Aim Evaluate long-term benefits of age-adjusted sagittal alignment in adult spinal deformity surgery by integrating PI–LL, PT, TPA, and SVA using hierarchical cluster analysis.

Cohort Retrospective review of 386 ASD patients undergoing ≥5-level fusion including sacrum/pelvis, with minimum 2-year follow-up (mean follow-up 36.6 months).

Targeting method Postoperative offsets (target − current) for PI–LL, PT, TPA, and SVA were computed using published age-adjusted formulas from 6-week radiographs (or immediate postop if early PJK).

Clustering outcome Patients stratified into 3 clusters (A: 72, B: 211, C: 103) with cluster A undercorrected, cluster B balanced/matched, and cluster C overcorrected trends across all parameters.

Mechanical complications PJK/PJF rates differed by cluster, highest in cluster C (37.9%) vs cluster B (27.5%) and cluster A (20.9%) (P = .046).

Patient-reported outcomes At final follow-up, cluster B had significantly better ODI and SRS-22r outcomes than clusters A and C.

Parameter relationships Offsets showed strong correlations: PI–LL with PT (r = 0.77) and PI–LL with TPA (r = 0.79); weaker with SVA (r = 0.43).

Practical implication A balanced multi-parameter alignment profile (cluster B) best optimized outcomes while reducing complications, supporting integrating multiple sagittal targets rather than relying on a single parameter.

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Machine learning models for predicting patient satisfaction after adult spinal deformity surgery

J Neurosurg Spine 44:457–468, 2026

This clinical study develops and internally validates machine learning–guided logistic regression models to predict patient satisfaction 24 months after adult spinal deformity (ASD) surgery, using 213 patients and three feature-selection methods. Nine routinely measurable predictors—including postoperative WOMAC function, frailty, pelvic compensation, imaging MCID achievement, rFCSA, and SVA—were identified and ranked by SHAP for their influence on satisfaction.

The model showed strong discrimination (AUROC 0.846) and calibration, yielded a nomogram for individualized prognostication, and emphasizes modifiable targets for perioperative care and rehabilitation. Limitations include single-center retrospective design, modest sample size, and inclusion of postoperative variables limiting preoperative decision use.

Goal Develop and internally validate models to predict patient satisfaction 24 months after adult spinal deformity (ASD) surgery, using SRS-22r satisfaction (high satisfaction defined as score ≥ 4.5).

Cohort 213 ASD patients met criteria; 128 (60%) used for training and 85 (40%) for internal test validation.

Pipeline Used three ML feature-selection methods—LASSO, recursive feature elimination (RFE), and Boruta—and retained variables consistently selected by all three.

Final predictors Nine key indicators were retained: rFCSA, fatty infiltration, frailty, pelvic compensation, postoperative SVA, imaging MCID achievement, postoperative subtotal score, postoperative WOMAC function, and change in WOMAC function.

Model Built an interpretable logistic regression model from these predictors; binary cutoff optimized via ROC/Youden index, with SHAP used to rank feature importance.

Performance In the test set, the model achieved AUROC 0.846 and accuracy 0.812 (also reported AUPRC 0.894 and Brier score 0.153).

Top drivers (SHAP order) Higher postoperative WOMAC function, absence of frailty, imaging MCID achieved, larger WOMAC function improvement, higher rFCSA, higher postoperative subtotal, lower postoperative SVA, successful pelvic compensation, and lower fatty infiltration increased satisfaction likelihood.

Implication/limitation Intended mainly to identify modifiable factors to guide postoperative rehabilitation; practical preoperative counseling is limited because key inputs include postoperative variables, and external multicenter validation is still needed.

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Are there distinct patterns of clinical deficits in cervical deformity? A discriminant analysis of health-related quality of life measures

J Neurosurg Spine 44:242–252, 2026

This clinical study analyzes preoperative health-related quality of life (HRQOL) measures in 134 adults with cervical deformity (CD) to identify distinct clinical deficit patterns and their association with radiographic morphotypes. Using factor and cluster analyses on NDI, mJOA, and SWAL-QOL items, four patient clusters emerged: sleep/fatigue, low neck disability, dysphagia with severe neck disability, and myelopathy.

These HRQOL-derived clusters correlated with specific radiographic types among severe deformities: cervicothoracic, focal, and flat-neck morphotypes. The findings support integrating patient-reported clinical dimensions into CD classification systems to guide tailored surgical planning and outcome assessment.

Distinct HRQOL Patterns: Four distinct patterns of health-related quality of life (HRQOL) deficits were identified in patients with cervical deformity: sleep/fatigue impairment, low neck disability, severe dysphagia and neck disability, and predominant myelopathy.

Cluster Analysis: Principal component and cluster analyses using NDI, mJOA, and SWAL-QOL questionnaires grouped patients into four homogeneous outcome clusters, each reflecting a unique constellation of clinical deficits.

Radiographic Associations: Each HRQOL deficit pattern was significantly associated with specific cervical deformity morphotypes: severe dysphagia/neck disability with cervicothoracic deformity, myelopathy with focal deformity, and sleep/fatigue or low disability with flat neck deformity.

Clinical Implications: Recognizing these HRQOL patterns may inform tailored management strategies, surgical planning, and prognosis for different cervical deformity subtypes.

Measurement Tools: The study utilized validated patient-reported outcome measures: Neck Disability Index (NDI), modified Japanese Orthopaedic Association (mJOA) scale, and Swallowing Quality of Life (SWAL-QOL) questionnaire.

Radiographic Parameters: Comprehensive imaging assessments included cervical and spinopelvic alignment measures, such as cervical SVA, T1 slope, C2–7 lordosis, and T1S-CL mismatch.

Demographic Factors: No significant differences in age, sex, BMI, or most comorbidities were found across clusters, except for higher rates of depression and prior spine surgery in those with the most severe clinical deficits.

Classification Framework: Findings support integrating HRQOL measures with radiographic parameters for a more comprehensive, patient-centered cervical deformity classification system.

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Do all patients with adult scoliosis need instrumented fusion from T10 to the pelvis?

J Neurosurg Spine 44:195–204, 2026

This clinical review addresses whether adult scoliosis uniformly requires instrumented fusion from T10 to the pelvis, presenting diagnostic frameworks, radiographic assessment, and surgical decision-making. It contrasts full-length thoracolumbar–pelvic constructs with shorter, focal interventions, emphasizing individualized selection based on pain generators, balance, deformity location, and comorbidities.

The article reviews indications for extending fusions to upper thoracic levels, risks such as proximal junctional kyphosis, and evidence supporting limited fusion or decompression-only strategies when focal pathology (fractional curve, foraminal stenosis, olisthesis) explains symptoms. Multiple case examples illustrate practical application of the decision algorithm and outcomes.

Individualized Treatment: Not all adult scoliosis patients require instrumented fusion from T10 to the pelvis; surgical decisions should be based on the patient’s symptoms, pain generator, spinal balance, and radiographic findings rather than a one-size-fits-all approach.

Pain Source Identification: Careful identification of the pain generator (scoliosis-related, neurogenic, facet, or sacroiliac) is critical; many patients have back pain unrelated to scoliosis and may benefit from focal or limited procedures instead of extensive fusion.

Fusion Level Selection: The choice of upper instrumented vertebra (UIV) depends on curve characteristics, presence of kyphosis, risk of proximal junctional kyphosis (PJK), and patient-specific factors; fusion may end at T10, upper thoracic, or even lumbar levels as appropriate.

Limited/Focal Surgery: In select cases, limited fusion (e.g., of the major curve, concavity, or fractional curve) or even decompression alone can be effective, especially for patients with focal symptoms or significant comorbidities who cannot tolerate extensive surgery.

Fractional Curve Fusion: Fusion of only the fractional curve (typically L4–S1) is effective for radicular pain referable to this segment; careful preoperative assessment of coronal alignment and curve type is necessary to avoid postoperative imbalance.

Radiographic-Clinical Correlation: Surgical planning should integrate both radiographic parameters (sagittal vertical axis, pelvic incidence–lumbar lordosis mismatch, coronal balance) and the patient’s clinical presentation, as discordance may require further investigation.

Risks of Extensive Fusion: Long-segment fusions (T10–pelvis or longer) carry significant morbidity and complication risks; such approaches are best reserved for cases with severe, disabling symptoms, progressive deformity, or global imbalance.

Patient Preferences and Expectations: Surgical decisions must consider patient quality of life, goals, psychological profile, and willingness to accept surgical risks or possible reoperation, with shared decision-making emphasized

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The impact of Roussouly sagittal profile changes on postoperative outcomes

J Neurosurg Spine 43:609–615, 2025

This clinical study examines postoperative changes in Roussouly sagittal spinal profiles among 525 adult spinal deformity (ASD) patients and evaluates how shifts between Roussouly types influence mechanical complications and patient-reported outcomes up to two years after fusion surgery. Methods include radiographic classification (current SS-based and theoretical PI-based), HRQOL measures (ODI, SRS-22r, EQ-5D), and multivariate regression to link type changes with PJK/PJF and MCID attainment.

Key findings show 39–59% of patients experienced postoperative Roussouly shape changes, with certain transitions (R1→R2, R2→R4, R3→R4) associated with higher proximal junctional kyphosis/failure risk and R4→R3 linked to greatest mechanical complication risk. R2-mismatched patients had poorer ODI improvement and higher pelvic nonresponse, suggesting Roussouly matching should inform ASD surgical planning.

Roussouly Classification Changes: Postoperative changes in Roussouly sagittal profile are common after adult spinal deformity (ASD) surgery, with 39% of patients experiencing a change in Roussouly type at 6 weeks post-op; type 1 (R1) patients had the highest rate of change (59%) and type 4 (R4) the lowest (26.7%).

Mechanical Complication Risk: Certain Roussouly type changes significantly increase the risk of proximal junctional kyphosis (PJK) and mechanical complications, especially transitions from R1 to R2, R2 to R4, R3 to R4, and R4 to R3.

Health-Related Quality of Life (HRQOL): Overall, Roussouly type changes were not associated with significant differences in minimum clinically important difference (MCID) achievement for SRS-22r scores up to 2 years, except for a lower rate of ODI MCID attainment in R2-mismatched patients.

Surgical Invasiveness and Deformity Severity: R1 patients had the most severe baseline deformity and underwent more extensive surgery, which may contribute to higher rates of postoperative Roussouly type changes.

Matching Theoretical Roussouly Type: Only 48% of patients matched their theoretical (PI-based) Roussouly type postoperatively; those who matched, especially in the R2 group, had better functional outcomes and lower rates of pelvic nonresponse (PNR).

Clinical Implications: Maintaining or restoring the original Roussouly type during ASD surgery may reduce the risk of mechanical complications and improve early functional outcomes, particularly for R2 patients.

Limitations: The study was retrospective, single-center, and limited to 2-year follow-up, which may affect generalizability and long-term conclusions.

Surgical Planning: Accounting for Roussouly type changes and known risk factors (e.g., osteoporosis, advanced age) during surgical planning may help decrease postoperative complications.

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Cervical deformity correction: comparison of neurological, radiographic, and patient-reported outcome measures by three-column osteotomy level

J Neurosurg Spine 43:433–442, 2025

Three-column osteotomy (3CO) for cervical deformity at C7–T1 is linked to higher neurological deficits, less radiographic correction, and worse Neck Disability Index outcomes compared to T2–6 levels. Surgeons should prefer 3CO below T1 when feasible for better neurological and functional results.

• Study compared outcomes of three-column osteotomy (3CO) for cervical deformity at C7–T1 vs T2–6 levels.

• Patients with 3CO at C7–T1 had higher rates of new postoperative neurological deficits (56% vs 18%).

• T2–6 3CO resulted in greater radiographic correction (T1 slope and C2–T4 SVA) than C7–T1 3CO.

• Neck Disability Index (NDI) improved after T2–6 3CO but worsened after C7–T1 3CO at 1 year.

• All patients with neurological deficits had at least partial recovery; 20% achieved complete recovery.

• 3CO level selection is multifactorial, but caudal to T1 is recommended when feasible due to better outcomes.

• Study limitations include retrospective design and single-institution data.

• Largest study to date comparing neurological, radiographic, and patient-reported outcomes by 3CO level.

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Evaluation of Discrepancy Between Radiographic Success and Patient Satisfaction in Adult Spinal Deformity Surgery

Neurosurgery 97:821–828, 2025

Despite radiographic success in adult spinal deformity surgery, 24.1% of patients remained dissatisfied, mainly due to postoperative lumbar stiffness-related disability. Satisfaction was not linked to radiographic parameters but was independently predicted by the modified lumbar stiffness disability index, highlighting the importance of counseling patients about this trade-off.

• About 24.1% of patients were dissatisfied with adult spinal deformity (ASD) surgery despite radiographic success.

• Radiographic success was defined as optimal alignment, no mechanical complications, and no revision surgery.

• Patient satisfaction was measured using SRS-22; scores <4.0 indicated less satisfaction.

• Clinical outcomes (pain, disability, quality of life) improved after surgery, but lumbar stiffness (M-LSDI) worsened.

• No significant differences in radiographic parameters were found between satisfied and less satisfied groups.

• High postoperative lumbar stiffness (M-LSDI score) was the single independent risk factor for dissatisfaction.

• Longer fusion length was associated with higher lumbar stiffness and lower satisfaction.

• Patients should be informed about the trade-off between pain relief and increased lumbar stiffness before surgery.

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Does Anterior Lumbar Interbody Fusion Reduce Mechanical Complication and Pseudarthrosis Rate at the Lumbosacral Junction in Adult Spinal Deformity Surgery in Comparison to Posterior Lumbar Interbody Fusion?

Int J Spine Surg 2025, 19 (4) 409-417

In adult spinal deformity surgery, anterior lumbar interbody fusion (ALIF) at the lumbosacral junction significantly reduces mechanical complications, pseudarthrosis, and reoperation rates compared to posterior lumbar interbody fusion (PLIF), suggesting ALIF should be preferred unless direct posterior decompression is necessary.

• ALIF (anterior lumbar interbody fusion) at the lumbosacral junction significantly reduces mechanical complications and pseudarthrosis rates compared to PLIF (posterior lumbar interbody fusion) in adult spinal deformity (ASD) surgery.

• ALIF is associated with lower rates of implant-related pain and reoperation than PLIF.

• PLIF is an independent risk factor for mechanical complications in long-segment ASD constructs.

• ALIF results in significantly less blood loss, fewer transfusions, and shorter ICU and hospital stays than PLIF.

• ALIF provides superior biomechanical stability and fusion rates, likely due to better endplate preparation and larger cage footprint.

• PLIF remains suitable for cases requiring direct neural decompression, such as severe stenosis or spondylolisthesis.

• Surgical technique selection should consider patient anatomy, surgical goals, and specific pathology at the lumbosacral junction.

• Study limitations include retrospective design, single-center data, and potential selection bias; further multicenter studies are needed.

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Less is more: complication rates and outcome measures of intradiscal osteotomy versus pedicle subtraction osteotomy in adult spinal deformity

J Neurosurg Spine 43:313–323, 2025

In adults with spinal deformity, intradiscal osteotomy (IDO) is as effective as pedicle subtraction osteotomy (PSO) for lordosis restoration and sagittal balance, with similar complication rates but significantly less blood loss, shorter operative time, and less postoperative back pain at 3 months.

• Intradiscal osteotomy (IDO) and pedicle subtraction osteotomy (PSO) are both used to correct adult spinal deformity, aiming to restore lumbar lordosis and sagittal balance.

• IDO and PSO showed similar fusion rates and complication profiles, with no statistically significant difference in rates of proximal junctional kyphosis, hardware failure, DVT, wound infection, or pseudarthrosis.

• IDO resulted in significantly less estimated blood loss (800 ml vs. 1400 ml) and shorter operative time (7 vs. 8.5 hours) compared to PSO.

• IDO patients reported less back pain at 3 months post-op (VAS 1 vs. 3, p=0.01) than PSO patients.

• Both techniques effectively restored lumbar lordosis, but IDO achieved better postoperative sagittal vertical axis (SVA) correction (5 cm vs. 7 cm, p=0.01).

• Higher BMI was a significant risk factor for postoperative complications in both groups.

• IDO is less technically complex, preserves vertebral body integrity, and is more familiar to spine surgeons than PSO.

• IDO can be considered an effective and potentially safer alternative to PSO for selected adult spinal deformity patients.

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How to Reduce the Risk of Mechanical Failures in Adult Deformity Surgery: Comparing GAP Score and Roussouly Type Restoration

Global Spine Journal 2025, Vol. 0(0) 1–15

DOI: 10.1177/21925682251328285

This study investigates the predictors of mechanical failure in adult spinal deformity surgery, highlighting the significance of the GAP score and Roussouly type restoration in minimizing complications. A proper post-operative GAP Score and spinal alignment restoration are crucial for reducing mechanical failure rates.

Study Design and Methods

• Retrospective cohort study with a 5-year follow-up on adult spinal deformity cases.

• Inclusion criteria: Patients over 18, with at least 4 vertebrae fused.

• Data collected: Demographic, surgical, spinopelvic parameters, and complications.

Key Findings

• Mechanical Complications: Revision surgery rate was 40.6%.

• Higher post-operative GAP scores linked to increased junctional failure risk.

• Roussouly Type Restoration: Failure to restore original type increases mechanical failure risk.

Predictive Analysis

• GAP Score and Roussouly Type are top predictors for mechanical failure.

• Gradient Boosting model showed high predictive accuracy (ASE 0.073).

• Kaplan-Meier Analysis: Higher GAP scores linked to earlier junctional failures.

Recommendations

• Surgical Planning: Restore original Roussouly type and achieve proper lumbar lordosis.

• Avoid Pelvic Retroversion: Ensure proper global balance.

Statistical Analysis

• Logistic regression confirmed GAP score and Roussouly type as significant predictors.

• ROC Curves: Moderate association between GAP score and revision surgery need.

Limitations

• Retrospective design with potential selection bias.

• Asymmetrical sample size of GAP score groups.

Level of Evidence

3 retrospective cohort study

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The gap between surgeon goal and achieved sagittal alignment in adult cervical spine deformity surgery

J Neurosurg Spine 42:309–319, 2025

This study assessed surgeons’ ability to achieve preoperative sagittal alignment goals in adult cervical spine deformity surgeries. Results showed significant deviations from targets, especially in severe deformities, highlighting the need for improved surgical planning and personalized implants.

Study Overview

• Objective: Assess surgeons’ ability to achieve preoperative sagittal alignment goals in CSD surgery.

• Methods: Prospective study with adult CSD patients across 13 North American centers.

• Patient Demographics: Mean age 63.6 years; 51.1% women; 38.6% had previous cervical fusion.

Key Findings

• Alignment Goals: Surgeons failed to meet goals by 17.2 mm for C2–7 SVA, 10.3° for Cobb angle.

• Factors Affecting Outcomes: Greater baseline TK linked to better Cobb angle achievement.

• Surgical Planning: 60% used PACS, 33.3% used spine-specific software.

• Tools and Criteria: Ames/ISSG criteria used by 33.3% of surgeons; others individualized goals.

Challenges and Recommendations

• Severe Deformities: More challenging to achieve alignment goals in severe cases.

• Need for Advancements: Personalized implants could improve intraoperative goal achievement.

• Alignment Correlations: Strong correlation for C7–S1 SVA, weak for C2–7 SVA.

Statistical Analysis

• Offset Groups: Patients categorized by offset magnitude from goal alignment.

• Significant Associations: Lower baseline TS-CL associated with better TS-CL goal achievement.

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Hook Fixation at Uppermost Instrumented Vertebra +1 Reduced Proximal Junctional Failure in Adult Patients With Spinal Deformity Having Achieved Optimal Deformity Correction by Sagittal Age-Adjusted Score

Neurosurgery 96:308–317, 2025

• Study Focus: The study investigates risk factors for proximal junctional failure (PJF) in elderly patients undergoing spinal deformity surgery despite achieving optimal sagittal correction.

• Methodology: Retrospective analysis of patients aged 60+ who underwent ≥5-level spinal fusion, focusing on those achieving optimal sagittal correction relative to the sagittal age-adjusted score (SAAS).

• Key Findings: High body mass index (BMI), high lumbar distribution index (LDI), and absence of hook fixation at UIV + 1 are significant risk factors for PJF.

• Statistical Analysis: Multivariate analysis confirmed these risk factors, with BMI and LDI showing significant predictive power for PJF development.

• Clinical Implications: Managing BMI, LDI, and ensuring hook fixation at UIV + 1 could reduce PJF rates, even with optimal sagittal correction.

• Limitations: The study’s generalizability is limited by the predominance of patients with UIV in the lower thoracic spine and inconsistent use of preventive methods.

• Conclusion: Proper management of identified risk factors, along with optimal sagittal correction, may further decrease PJF incidence.

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Pedicle Subtraction Osteotomies for Surgical Correction of Fixed Sagittal Imbalance: A Meta-Analysis and Systematic Review

Neurosurgery 95:1223–1231, 2024

Disruption of the spine’s sagittal balance is associated with significant negative impacts on quality of life. Compared with other spinal osteotomies, pedicle subtraction osteotomy (PSO), which can potentially offer greater correction, is considered technically challenging and performed at lower rates. The aim of this study was to review the use of PSO to correct fixed sagittal imbalance and assess its efficacy and associated perioperative complications.

METHODS: In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, the PubMed, EBSCO host, MEDLINE, and Google Scholar databases were queried for full-text English manuscripts published from 1961 to 2022, exploring PSO for the management of fixed sagittal imbalance. Studies were included if they reported preoperative and postoperative radiographic measurements. The mean Methodological Index for Nonrandomized Studies (MINORS) for included articles was 9.6 ± 1.1. The outcomes of interest included etiology, operative time, blood loss, complications, radiographic outcomes, and patient-reported outcomes. Statistical analysis was performed using a random-effects, inverse variance-weighted meta-analysis of observational data. Pre and postoperative radiographic and clinical outcomes were compared using a Student t-test.

RESULTS: Fourteen studies with 595 patients were included. Meta-analysis showed that the mean operative time was 7.2 ± 2.0 hours, and the average blood loss was 2033 ± 629 mL. After PSO, there was a significant improvement in sagittal vertebral axis (12.41-3.92 cm, P = .0003), LL (13.35°-42.60°, P = .000002), PSO angle (5.11°to À26.91°, P = .0001), and Oswestry Disability Index (55.36-27.35, P = .02). Common complications include pseudarthrosis (8.1%), neurological deficits (7.8%), and proximal junctional failure (6.0%).

CONCLUSION: PSO offers significant correction of sagittal vertebral axis, lumbar lordosis, PSO angle, and Oswestry Disability Index scores despite its reduced utilization in recent years. Blood loss and high complication rates must be considered when evaluating the efficacy of this procedure; however, surgeon experience and operative techniques can be used to reduce morbidity.

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The Role of Pelvic Compensation in Sagittal Balance and Imbalance: The Impact of Pelvic Compensation on Spinal Alignment and Clinical Outcomes Following Adult Spinal Deformity Surgery

Neurosurgery 95:1307–1316, 2024

The Scoliosis Research Society (SRS)-Schwab system does not include a pelvic compensation (PC) subtype, potentially contributing to gaps in clinical characteristics and treatment strategy for deformity correction. It also remains uncertain as to whether PC has differing roles in sagittal balance (SB) or imbalance (SI) status. To compare radiological parameters and SRS-22r domains between patients with failed pelvic compensation (FPC) and successful pelvic compensation (SPC) based on preoperative SB and SI.

METHODS: A total of 145 adult spinal deformity patients who received deformity correction were analyzed. Radiographic and clinical outcomes were collected for statistical analysis. Patients were classified into 4 groups based on the median value of PT/PI ratio (PTr) and the cutoff value of SB. Patients with low PTr and high PTr were defined as FPC and SPC, respectively. Radiographic and clinical characteristics of different groups were compared.

RESULTS: Patients with SPC exhibited significantly greater improvements in lumbar lordosis, pelvic tilt, PTr, and T1 pelvic angle as compared to patients with FPC, irrespective of SB or SI. No apparent differences in any of SRS-22r domains were observed at follow-up when comparing the SB-FPC and SB-SPC patients. However, patients with SI-SPC exhibited significantly better function, self-image, satisfaction, and subtotal domains at follow-up relative to those with SI-FPC. When SI-FPC and SISPC patients were subdivided further based on the degree of PI-LL by adjusting for age, the postoperative function and self-image domains were significantly better in the group with overcorrection of PI-LL than undercorrection of PI-LL in SI-FPC patients. However, no differences in these SRS-22r scores were observed when comparing the subgroups in SI-SPC patients.

CONCLUSION: Flexible pelvic rotation is associated with benefits to the correction of sagittal parameters, irrespective of preoperative SB or SI status. However, PC is only significantly associated with clinical outcomes under SI. Patients with SIFPC exhibit poorer postoperative clinical outcomes, which should be recommended to minimize PI-LL.

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Segmental Sagittal Alignment in Lumbar Spinal Fusion: A Review of Evidence-Based Evaluation of Preoperative Measurement, Surgical Planning, Intraoperative Execution, and Postoperative Evaluation

Operative Neurosurgery 27:533–548, 2024

Maintaining and restoring global and regional sagittal alignment is a well-established priority that improves patient outcomes in patients with adult spinal deformity. However, the benefit of restoring segmental (level-by-level) alignment in lumbar fusion for degenerative conditions is not widely agreed on. The purpose of this review was to summarize intraoperative techniques to achieve segmental fixation and the impact of segmental lordosis on patient-reported and surgical outcomes.

METHODS: In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, PubMed, Embase, Cochrane, and Web of Science databases were queried for the literature reporting lumbar alignment for degenerative lumbar spinal pathology. Reports were assessed for data regarding the impact of intraoperative surgical factors on postoperative segmental sagittal alignment and patient-reported outcome measures. Included studies were further categorized into groups related to patient positioning, fusion and fixation, and interbody device (technique, material, angle, and augmentation).

RESULTS: A total of 885 studies were screened, of which 43 met inclusion criteria examining segmental rather than regional or global alignment. Of these, 3 examined patient positioning, 8 examined fusion and fixation, 3 examined case parameters, 26 examined or compared different interbody fusion techniques, 5 examined postoperative patient-reported outcomes, and 3 examined the occurrence of adjacent segment disease. The data support a link between segmental alignment and patient positioning, surgical technique, and adjacent segment disease but have insufficient evidence to support a relationship with patient-reported outcomes, cage subsidence, or pseudoarthrosis.

CONCLUSION: This review explores segmental correction’s impact on short-segment lumbar fusion outcomes, finding the extent of correction to depend on patient positioning and choice of interbody cage. Notably, inadequate restoration of lumbar lordosis is associated with adjacent segment degeneration. Nevertheless, conclusive evidence linking segmental alignment to patient-reported outcomes, cage subsidence, or pseudoarthrosis remains limited, underscoring the need for future research.

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