Oral Presentation 51st International Society for the Study of the Lumbar Spine Annual Meeting 2025

A comparison of postoperative outcomes in surgical treatment for spinal metastasis focused on the institutional function: Analysis of a nationwide administrative database in Japan (115380)

Kentaro Yamada 1 , Miyako Toba 2 , Hiroyuki Sato 3 , Takashi Hirai 1 , Akihiro Hirakawa 3 , Kiyohide Fushimi 4 , Toshitaka Yoshii 1
  1. Dept. of Orthop. Surg., Institute of Science Tokyo, Tokyo, Japan
  2. Dept. of Quality Management Center, Institute of Science Tokyo Hosp., Tokyo, Japan
  3. Dept. of Clinical Biostatistics, Institute of Science Tokyo, Tokyo, Japan
  4. Dept. of Health Policy and Informatics Section, Institute of Science Tokyo, Tokyo, Japan

Introduction. Multidisciplinary approaches to bone metastasis have become common in Japan, especially in cancer centers. However, whether treatment outcomes for spinal metastasis surgery differ by institutional function remains controversial. This study aimed to investigate the impact of institutional function (cancer center and surgical volume for spine surgery) on in-hospital outcomes after surgical treatment for spinal metastasis using a nationwide administrative database.

Methods. Data of patients who underwent surgical procedures for spinal metastasis between 2012 and 2020 were extracted from the Diagnosis Procedure Combination (DPC) database. In-hospital outcomes included in-hospital mortality, 30-day mortality, length of stay until discharge home, postoperative complications, and unfavorable ambulatory status. Unfavorable ambulatory was defined as non-ambulatory status at discharge or deterioration of ambulatory status assessed based on a previous study. Univariate and multivariate analyses were performed to investigate the association between cancer center/surgical volume and each outcome while adjusting for potential confounders.

Results. A total of 10,320 patients were included in this study. Among them, 5,261 patients were treated at cancer centers. The median annual surgical volume for spine surgery was 166 cases. Cancer centers were more included in institutions with approximately 200 surgical volumes of spine surgery per year (Figure 1). The overall in-hospital mortality was 8.6%, and the length of stay after spinal surgery was a median 33 days. The 30-day mortality was 6.2%. More than half of the patients (58.4%) were discharged directly home after surgery. Complications and unfavorable ambulatory status at discharge were observed in 7.8% and 39.4%, respectively.

  The 30-day mortality was lower in cancer centers than in non-cancer centers (odds ratio [OR]: 0.841, 95% confidence interval [CI]: 0.709–0.999, P = 0.0483) and in high-volume hospitals for spine surgery than in low-volume hospitals (OR per 50 cases: 0.958, 95% CI: 0.928–0.990, P = 0.0101, Figure 2). The length of stay until discharge home, postoperative complications, and postoperative unfavorable ambulatory status did not differ by cancer center or surgical volume.

Discussion. The short-term mortality was lower in cancer centers or high-volume hospitals, whereas postoperative complications and ambulatory outcomes did not differ by institutional function. A deeper understanding of the multidisciplinary approaches or processes of care adopted at these institutions is needed to deliver similar outcomes in other hospitals to patients with spinal metastasis.

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