Perioperative hidden blood loss and risk factors in transforaminal lumbar interbody fusion calculated by a new method

Abstract

BACKGROUND: Transforaminal lumbar interbody fusion is one of the main surgical methods for treating degenerative lumbar diseases such as lumbar disc herniation, lumbar spinal stenosis, and lumbar spondylolisthesis. Hidden blood loss refers to the concealed loss of blood volume in patients, which is often overlooked by people. OBJECTIVE: To evaluate the perioperative blood loss during transforaminal lumbar interbody fusion using a new method, calculate the hidden blood loss based on the new method, and analyze its risk factors. METHODS: The medical records of 93 patients with lumbar degenerative diseases (lumbar spinal stenosis, lumbar disc herniation, and lumbar spondylolisthesis) who were hospitalized in the Department of Spine Surgery of Second Affiliated Hospital of Soochow University from October 2023 to October 2024 were retrospectively analyzed. The general data of patients were collected, such as age, gender, height, body mass, body mass index, and whether they had hypertension and diabetes; surgical data, such as the number of surgical segments, operation time, and American Society of Anesthesiologists anesthesia grade; laboratory tests, such as prothrombin time, activated partial thromboplastin time, international normalized ratio, platelet count, fibrinogen, and D-dimer level. Pearson or Spearman correlation analysis was used to explore the correlation between patient characteristics and postoperative hidden blood loss, and multivariate linear regression analysis was utilized to determine the independent risk factors for postoperative hidden blood loss. RESULTS AND CONCLUSION: (1) The average hidden blood loss calculated by the new method for transforaminal lumbar interbody fusion was (284.24±352.76) mL, accounting for 58.6% of total blood loss; while the traditional method calculated an average hidden blood loss of (165.77±339.89) mL, accounting for 34.15% of total blood loss, with a significant difference between the two (P < 0.05). (2) In univariate analysis, hidden blood loss was positively correlated with the number of segments (r=0.213, P=0.040) and operation time (r=0.210, P=0.043), and negatively correlated with platelet count (r=-0.324, P=0.018). (3) In multivariate linear regression analysis, decreased platelet count was an independent risk factor for hidden blood loss (P=0.016). (4) These findings suggest that the new method provides a more accurate estimation of hidden blood loss, and hidden blood loss is an important component of perioperative total blood loss; increased number of segments, prolonged operation time, and decreased platelet count are risk factors for hidden blood loss in transforaminal lumbar interbody fusion, with decreased platelet count being an independent risk factor.

1. Introduction

With the growth of the aging population, the incidence of lumbar disc herniation, spinal stenosis, lumbar spondylolisthesis, and other degenerative lumbar diseases is also increasing [1-5]. These conditions often cause low back and leg pain, severely affecting patients' quality of life. Severe degenerative lumbar diseases or those that fail conservative treatment typically require surgical intervention. Transforaminal lumbar interbody fusion (TLIF) is currently one of the main surgical methods for treating degenerative lumbar diseases [5-9]. This surgical approach achieves adequate decompression while enhancing spinal stability through bone grafting and internal fixation, improving sagittal balance, and effectively alleviating clinical symptoms [10-12].

Literature reviews and meta-analyses have demonstrated that compared with posterior lumbar interbody fusion, TLIF via a unilateral posterior approach allows circumferential fusion with less retraction of the dura and nerve roots, resulting in a lower incidence of neurological injury. It preserves the spinous process, interspinous and supraspinous ligaments, contralateral lamina, and ligamentum flavum, allowing early mobilization, facilitating recovery of paraspinal muscle function, and resulting in fewer complications and shorter operative time [5,13-16]. However, TLIF is associated with varying degrees of postoperative anemia, especially in multilevel procedures. If not corrected promptly, it can lead to various complications, including prolonged hospital stay and increased mortality [17-18]. Therefore, surgeons pay close attention to intraoperative blood loss and postoperative drainage in perioperative management. Nevertheless, clinical observations reveal that changes in hemoglobin and hematocrit are inconsistent with intraoperative blood loss and postoperative drainage.

The concept of hidden blood loss was first introduced by Sehat et al. in 2000, who found that hidden blood loss accounted for 26% and 49% of total perioperative blood loss in total knee arthroplasty and total hip arthroplasty, respectively [19]. Previous studies attributed total blood loss solely to visible bleeding, including intraoperative hemorrhage and postoperative drainage. However, total blood loss is significantly greater than visible bleeding, indicating the presence of hidden blood loss.