Tag: Proximal junctional failure

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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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The Effect of Transpedicular Injection of Recombinant Human Bone Morphogenetic Protein-2/Beta-Tricalcium Phosphate Carrier on the Prevention of Proximal Junctional Kyphosis in Adult Spinal Deformity Surgery: A Pilot Study

Neurosurgery 96:986–996, 2025

The study explores the use of recombinant human bone morphogenetic protein-2 (rhBMP-2) with beta-tricalcium phosphate (β-TCP) to prevent proximal junctional kyphosis (PJK) in adult spinal deformity surgery. Results indicate reduced PJK incidence and increased bone density at the upper instrumented vertebra.

• The study explores the use of transpedicular injection of recombinant human bone morphogenetic protein-2 (rhBMP-2) with a beta-tricalcium phosphate (β-TCP) carrier to prevent proximal junctional kyphosis (PJK) in adult spinal deformity (ASD) surgery.

• 25 patients received rhBMP-2 injections, and their outcomes were compared with two control groups with 66 and 63 patients each.

• Results showed a significantly lower incidence of PJK in the rhBMP-2 group compared to control groups.

• The injection also led to a significant increase in trabecular bone density at the upper instrumented vertebra (UIV).

• Multivariate analysis indicated that rhBMP-2 injection at the UIV had a protective effect against PJK.

• The study suggests that this method can be easily integrated into surgical procedures to enhance bone density and reduce PJK risk.

• Limitations include the small sample size and lack of randomization, warranting further studies.

• The study concludes that rhBMP-2/β-TCP injection is a promising strategy for preventing PJK in ASD surgery.

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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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Gravity Line–Hip Axis Offset as a Guide for Global Alignment to Prevent Recurrent Proximal Junctional Kyphosis/Failure

Operative Neurosurgery 26:268–278, 2024

Proximal junctional kyphosis/failure (PJK/F) is a potentially serious complication after adult spinal deformity (ASD) corrective surgery. Recurrent PJK/F is especially troublesome, necessitating fusion extension and occasionally resulting in irreversible neurological deficits. The gravity line (GL) offers valuable insights into global sagittal balance. This study aims to examine the postoperative GL–hip axis (GL-HA) offset as a critical risk factor for recurrent PJK/F.

METHODS: We retrospectively reviewed patients with ASD who had undergone revision surgery for initial PJK/F at a single academic center. Patients were categorized into 2 groups: nonrecurrent PJK/F group and recurrent PJK/F group. Demographics, surgical characteristics, preoperative and postoperative parameters of spinopelvic and global alignment, and the Scoliosis Research Society-22 scores were assessed. We examined these measures for differences and correlations with recurrent PJK/F.

RESULTS: Our study included 32 patients without recurrent PJK/F and 28 patients with recurrent PJK/F. No significant differences were observed in baseline demographics, operative characteristics, or Scoliosis Research Society-22 scores before and after surgery. Importantly, using a cutoff of À52.6 mm from logistic regression, there were considerable differences and correlations with recurrent PJK/F in the postoperative GL-HA offset, leading to an odds ratio of 7.0 (95% CI: 1.94-25.25, P = .003).

CONCLUSION: Postoperative GL-HA offset serves as a considerable risk factor for recurrent PJK/F in patients with ASD who have undergone revision surgery. Overcorrection, with GL-HA offset less than À5 cm, is associated with recurrent PJK/F. The instrumented spine tends to align the GL near the HA, even at the cost of proximal junction.

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Characteristics of patients undergoing revision surgery for proximal junctional failure after adult spinal deformity surgery

J Neurosurg Spine 37:402–409, 2022

Score on the proximal junctional kyphosis severity scale (PJKSS) has been validated to show good correlations with likelihood of revision surgery for proximal junctional failure (PJF) after surgical treatment of adult spinal deformity (ASD). However, if the patient has progressive neurological deterioration, revision surgery should be considered regardless of severity based on PJKSS score. This study aimed to revalidate the correlation of PJKSS score with likelihood of revision surgery in patients with PJF but without neurological deficit. In addition, the authors provide the cutoff score on PJKSS that indicates need for revision surgery.

METHODS A retrospective study was performed. Among 360 patients who underwent fusion of more than 4 segments including the sacrum, 83 patients who developed PJF without acute neurological deficit were included. Thirty patients underwent revision surgery (R group) and 53 patients did not undergo revision surgery (NR group). All components of PJKSS and variables other than those included in PJKSS were compared between groups. The cutoff score on PJKSS that indicated need for revision surgery was calculated with receiver operating characteristic curve analysis. Multivariate analysis with logistic regression was performed to identify which variables were most predictive of revision surgery.

RESULTS The mean patient age at the time of index surgery was 69.4 years, and the mean fusion length was 6.1 segments. All components of PJKSS, such as focal pain, instrumentation problem, change in kyphosis, fracture at the uppermost instrumented vertebra (UIV)/UIV+1, and level of UIV, were significantly different between groups. The average total PJKSS score was significantly greater in the R group than in the NR group (6.0 vs 3.9, p < 0.001). The calculated cutoff score was 4.5, with 70% sensitivity and specificity. There were no significant between-group differences in patient, surgical, and radiographic factors (other than the PJKSS components). Three factors were significantly associated with revision surgery on multivariate analysis: instrumentation problem (OR 8.160, p = 0.004), change in kyphosis (OR 4.809, p = 0.026), and UIV/UIV+1 fracture (OR 6.462, p = 0.002).

CONCLUSIONS PJKSS score positively predicted need for revision surgery in patients with PJF who were neurologically intact. The calculated cutoff score on PJKSS that indicated need for revision surgery was 4.5, with 70% sensitivity and specificity. The factor most responsible for revision surgery was bony failure with > 20° focal kyphotic deformity. Therefore, early revision surgery should be considered for these patients even in the absence of neurological deficit.

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Different Risk Factors of Proximal Junctional Kyphosis and Proximal Junctional Failure Following Long Instrumented Fusion to the Sacrum for Adult Spinal Deformity

Neurosurgery 80:279–286, 2017

The failure modes, time to development, and clinical relevance are known to differ between proximal junctional kyphosis (PJK) and proximal junctional failure (PJF). However, there are no reports that study the risk factors of PJK and PJF separately.

OBJECTIVE: The aim of this study was to investigate the risk factors for PJK and PJF separately.

METHODS: A retrospective study of 160 consecutive patients who underwent a long instrumented fusion to the sacrum for adult spinal deformity with a minimum follow-up of years was conducted. A separate survivorship analysis of PJK and PJF was performed using the Cox proportional hazards model for the 3 categorical parameters of surgical, radiographic, and patient factors.

RESULTS: PJK developed in 27 patients (16.9%) and PJF in 29 patients (18.1%). The median survival time was 17.0 months for PJK and 3.0 months for PJF. Multivariate analyses revealed that a high body mass index was an independent risk factor for PJK (hazard ratio [HR] = 1.179), whereas the significant risk factors for PJF were older age, the presence of osteoporosis, the uppermost instrumented vertebra level at T11-L1, and a greater preoperative sagittal vertical axis (HR = 1.082, 6.465, 5.236, and 1.017, respectively). A large correction of sagittal deformity was shown to be a risk factor for PJF on univariate analyses, but not on multivariate analyses.

CONCLUSION: PJK developed at a median of 17 months and PJF at a median of 3 months. A high body mass index was an independent risk factor for PJK, whereas older age, osteoporosis, uppermost instrumented vertebra level at the thoracolumbar junction, and greater preoperative sagittal vertical axis were risk factors for PJF.

 

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