Validation of Age-adjusted Ideal Sagittal Alignment in Terms of Proximal Junctional Failure and Clinical Outcomes in Adult Spinal Deformity

Abstract

Study Design. Retrospective study. Objective. To validate the age-adjusted ideal sagittal alignment in terms of proximal junctional failure (PJF) and clinical outcomes. Summary of Background. It is reported that optimal sagittal correction with regard to the age-adjusted ideal sagittal alignment reduces the risk of PJF development. However, few studies have validated this concept. The age-considered optimal correction is likely to be undercorrection in terms of conventional surgical target, such as pelvic incidence (PI)−lumbar lordosis (LL) within ± 9°. Therefore, the clinical impact of age-adjusted sagittal alignment should be evaluated along with radiographic effect. Materials and Methods. Adult spinal deformity patients, aged 50 years and above, who underwent greater than or equal to fourlevel fusion to sacrum with a minimum of four years of follow-up data were included in this study. Radiographic risk factors for PJF (including age-adjusted ideal PI−LL) were evaluated with multivariate analyses. Three groups were created based on PI−LL offset between age-adjusted ideal PI−LL and actual actual PI−LL. . undercorrection, ideal correction, and overcorrection. Clinical outcomes were compared among the three groups.Results. This study included 194 adult spinal deformity patients. The mean age was 68.5 years and there were 172 females (88.7%). PJF developed in 99 patients (51.0%) at a mean postoperative period of 14.9 months. Multivariate analysis for PJF revealed that only PI−LL offset group had statistical significance. The proportion of patients with PJF was greatest in the overcorrection group followed by the ideal correction and undercorrection groups.Overcorrected patients regard to the age-adjusted ideal alignment showed poorer clinical outcomes than the other patient groups. Conclusions. Overcorrection relative to age-adjusted sagittal alignment increases the risk of PJF development and is associated with poor clinical outcomes. Older patients and those with small PI are likely to be overcorrected in terms of the age-adjusted PI−LL target. Therefore, the age-adjusted alignment should be considered more strictly in these patients.

A Validation Study of Four Preoperative Surgical Planning Tools for Adult Spinal Deformity Surgery in Proximal Junctional Kyphosis and Clinical Outcomes

“…Since the concept of age-adjusted alignment goals was introduced in 2016 to individualize conventional PI-LL mismatch considering patient age, 5 several studies have reported that appropriate correction relative to the age-adjusted PI-LL target reduced PJK risk. 10,32,33 As with previous studies, we also found that significantly fewer patients developed PJK in the matched…”

Sagittal Section Hounsfield Units of the Upper Instrumented Vertebrae as a Predictor of Proximal Junctional Vertebral Fractures Following Adult Spinal Deformity Surgery

“…Furthermore, patients were categorized according to Roussouly’s newly proposed classification for categorizing the progression of asymptomatic spinal typologies under degenerative conditions based on the SS and LL contours [ 28 ]. Patients were also grouped according to the degree of LL correction relative to PI by adjusting for age, which uses the following formula [ 29 , 30 ]: (age-adjusted ideal PI–LL)–(postoperative PI–LL). The three groups were as follows: group U (undercorrection; <10°), group I (ideal correction; −l10° to 10°), and group O (overcorrection; >10°).…”

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

“…Here, we elaborate on the Scoliosis Research Society (SRS)-Schwab classification, age-adjusted sagittal alignment goals, the global alignment and proportion (GAP) score, and the Roussouly algorithm. 2,6,7,9,[31][32][33][34][35][36][37][38][39][40]…”