Preoperative prediction of early mortality after surgery for spinal metastases.

OBJECTIVE: The objective of this study was to provide a convenient preoperative prediction of the risk of early postoperative mortality. MATERIALS AND METHODS: This retrospective study included patients who underwent surgery for spinal metastasis at our hospital between 2009 and 2021. Preoperative blood test data of all patients were collected, and the survival time was calculated by dividing the blood data. A multivariate analysis was conducted using a Cox proportional hazards model to identify prognostic factors. RESULTS: The study population included 83 patients (average: 64.5 years), 22 of whom died within 3 months. The most common lesion was the thoracic spine, and incomplete paralysis was observed in 57 patients. The surgical methods included posterior implant fixation (n = 17), posterior decompression (n = 31), and posterior decompression with fixation (n = 35). In the univariate analysis, the presence of abnormal values was significantly associated with postoperative survival in six preoperative blood collection items (hemoglobin, C-reactive protein, albumin, white blood cell, gamma-glutamyl transpeptidase, and lactate dehydrogenase). In a multivariate analysis, four test items (hemoglobin, C-reactive protein, white blood cell, and lactate dehydrogenase) were identified as independent prognostic factors.Comparing cases with ≥3 abnormal values among the above four items (high-risk group; n = 23) and those with ≤2 (low-risk group; n = 60), there was a significant difference in survival time. In addition, it was possible to predict cases of early death within 3 months after surgery with 73% sensitivity and 89% specificity. CONCLUSIONS: The study showed that four preoperative blood test abnormalities (hemoglobin, C-reactive protein white blood cell, and lactate dehydrogenase) indicated the possibility of early death within 3 months after surgery.

Long-term Evaluation Using Finite Element Analysis of Bone Atrophy Changes after Locking Plate Fixation of Forearm Diaphyseal Fracture.

Purpose: To determine the optimal timing of plate removal in patients with forearm diaphyseal fractures fixed with a locking plate via the analysis of bone atrophy over time. Methods: The study subject was a 56-year-old man. Computed tomography was performed at 0.5, 1, 1.5, 2, 3, 4, and 5 years after plate fixation. Finite element analysis was performed to measure the fracture load of the radius and ulna. The fracture loads of the affected and healthy sides were compared, and their ratio was calculated by dividing the value of the affected side by that of the healthy side at each time point. Results: The strength of the radius and ulna was 40.9% and 29.3%, respectively, on the healthy side at 1 year after surgery. The fracture load increased from the second to the third postoperative year; the strength of the radius and ulna was 62.2% and 37.3%, respectively, on the healthy side after the third year. However, after the third year, the fracture load declined and reached 38.8% and 18.9% for the radius and ulna, respectively, on the healthy side by the fifth postoperative year. Conclusions: The long-term fixation of forearm diaphyseal fractures using a locking plate leads to progressive bone atrophy. Future bone atrophy during long-term locking plate fixation without removal should be monitored. Type of study/level of evidence: Therapeutic IV.