Effect of Preoperative Nutritional Status on Postoperative Clinical Outcomes of Patients with Metastatic Spinal Tumors: Japan Association of Spine Surgeons with Ambition Multicenter Study

Abstract

Study design: A multicenter prospective study.

Objective: To evaluate the effect of preoperative nutritional status, assessed using the Prognostic Nutritional Index (PNI), on clinical outcomes, including survival prognosis, postoperative complications, hospitalization duration, and functional prognosis, in patients with metastatic spinal tumors undergoing surgery.

Summary of background data: Malnutrition is common in patients with cancer and is associated with poor clinical outcomes. However, data on the role of nutritional status in metastatic spinal tumors are limited.

Methods: We included 309 patients who underwent surgery for metastatic spinal tumors between October 2018 and March 2021. Patients were divided into two groups: normal nutrition (PNI ≥40) and malnutrition (PNI <40). Clinical outcomes, including 1-year mortality, postoperative complications, and functional improvements (performance status, Frankel grade, Barthel Index, Vitality Index, and EuroQol 5-Dimension 5-level), were compared using propensity score matching to adjust for confounding factors, such as age, sex, preoperative chemotherapy, performance status, primary tumor type, and visceral metastases.

Results: Thirty-six percent of patients were malnourished. After propensity score matching, the malnutrition group had a significantly higher mortality rate within 1 year than the normal nutrition group (55% vs. 31%, P<0.001) and showed limited physical improvement, including neurological recovery, 1 month postoperatively. However, improvements in motivation and quality of life (QOL) were comparable between the groups, and physical function recovery at 6 months was similar. No significant differences in postoperative complications or length of hospital stay were observed between the groups.

Conclusion: Preoperative malnutrition was observed in 36% of patients with metastatic spinal tumors who underwent surgery and was associated with a poor postoperative survival prognosis and delayed physical recovery. However, surgical treatment improved motivation, QOL, and physical function 6 months after surgery. These findings highlight the importance of assessing the nutritional status preoperatively and considering both survival and functional prognoses when selecting surgical treatment for patients with malnutrition.

Keywords: Barthel Index; Metastatic spinal tumors; Prognostic Nutritional Index (PNI); malnutrition; neurological outcome; performance status; postoperative complications; propensity score matching; quality of life; surgical treatment; survival prognosis.