Limited Predictive Performance of the Global Alignment and Proportion (GAP) Score for Mechanical Complications in Older Asian Patients With Adult Spinal Deformity: A Multicenter Validation Study
Year: 2026
Type: article
Study design: Observational Study
Abstract: Study Design Retrospective cohort study. Objectives Surgery for adult spinal deformity (ASD) is associated with postoperative mechanical complications (MCs), such as proximal junctional kyphosis (PJK). The applicability of the Global Alignment and Proportion (GAP) score for predicting MCs in older Asians remains unclear. This study aimed to evaluate the validity of the GAP score in Asians patients by stratifying them into younger and older groups. Methods We studied 274 patients who had undergone multi-level spinal fusion and were followed up for at least 2 years. Patients were divided into a younger group (Under-69, n = 122) and an older group (Over-70, n = 152). MCs were assessed at 2 years postoperatively. Propensity score matching was performed to compare the incidence of MCs across groups. Logistic regression models were used to examine the interaction between GAP score and age. Results MC occurred in 93 patients (34%), with no significant differences between groups. In the Under-69 group, GAP scores did not correlate with MC occurrence. In contrast, the in the Over-70 group patients with MCs had significantly lower GAP scores (6.6 ± 3.4 vs. 8.0 ± 3.2, P = 0.022). The interaction between GAP score and age was not significant in the logistic regression models. Conclusions The GAP score demonstrated limited predictive ability for MCs in this Asian ASD cohort, particularly in older patients. These findings suggest that alignment-based prediction models alone may be insufficient for MC risk stratification in aging populations.
Source: Global Spine Journal
Authors: Keisuke Ogura, Naoki Segi, Sadayuki Ito, Jun Ouchida, Ippei Yamauchi, Yukihito Ode, Yasuhiro Nagatani, Yuya Okada, Yosuke Takeichi, Yujiro Kagami, Hiroto Tachi, Kazuaki Morishita, Ryotaro Oishi, Yuichi Miyairi, Yoshinori Morita, Kazuma Ohshima, Hiroki Oyama, Ryuichi Shinjo, Tetsuya Ohara, Taichi Tsuji, Tokumi Kanemura, Shiro Imagama, Hiroaki Nakashima
Institutions: Anjo Kosei Hospital, Nagoya University, National Center for Geriatrics and Gerontology, Konan Kosei Hospital, Japanese Red Cross Nagoya Daiichi Hospital, Toyohashi Municipal Hospital, Japanese Red Cross Nagoya Daini Hospital, Chutoen General Medical Center, Meijo Hospital, Toyota Kosei Hospital
Language: English
Subfield: Surgery
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $2,650
OpenAlex ID: W7171858860