Introduction. Spinal metastasis can lead to pain, neurological deficit, and disruption of health-related quality of life, and sometimes needs surgical treatment. Both cancer diagnosis/treatment modality and surgical technique for the spine have been developed recently. Nationwide trends in the surgical treatment for metastatic spinal tumors have not been reported in the last decades. This study aimed to examine recent trends in the surgical treatment for spinal metastasis and in-hospital patient outcomes using nationwide administrative hospital discharge data.
Methods. This study included spinal surgery cases for metastatic spinal tumors including vertebroplasty using the Diagnosis Procedure Combination (DPC) database: a national inpatient database in Japan, from 2012 to 2020. The number of patients who underwent spinal surgery for non-metastatic spinal disorders at the institutions that have performed metastatic spine surgeries at least one case in the same year were also investigated. Trends in the surgical treatment for spinal metastasis, patients’ demographics, and in-hospital mortality/outcomes were investigated using Jonckheere-Terpstra trend test and Cochran-Armitage test. The postoperative unexpected ambulatory was defined as (1) non-ambulatory at discharge or (2) a decrease in mobility score of Barthel Index between admission and discharge.
Results. This study analyzed 10321 eligible patients with spinal metastasis with 473,391 patients without spinal metastasis. The surgical treatment for spinal metastasis increased 1.68 times from 877 in 2012 to 1479 in 2020, especially in fusion surgery from 84% in 2012 to 87% in 2020, whereas the proportion of metastatic spinal surgery retained with a slight increase in the 2 %s(Figure). Distributions of the primary site did not change whereas age was getting older. In-hospital death and length of stay decreased over time (9.9%–6.8%, p <0.001; 37 days–30 days, p <0.001). The postoperative complication retained stable (8.0%–8.5%, p=0.52). Postoperative unfavorable ambulatory slightly decreased (39%–36.9%, p=0.003).
Discussion. During the last decade, surgical treatment for spinal metastasis has increased in Japan. Age at the surgery was getting older, whereas the distribution of the primary site of tumors and preoperative comorbidity did not change. In-hospital mortality and length of stay decreased over time, whereas discharge to home and postoperative complications remained stable. The postoperative unfavorable ambulatory decreased slightly. The results of this study may provide useful information for healthcare policy or clinical research planning.