Hidden blood loss and the influential factors after percutaneous kyphoplasty surgery.

PURPOSE: Percutaneous kyphoplasty (PKP) is a minimally invasive procedure for the treatment of osteoporotic vertebral compression fractures (OVCFs). It is generally considered that there is little blood loss during the surgery. However, a significant perioperative hidden blood loss (HBL) is neglected. This study was to examine the amount of HBL and determine the influential factors during PKP.

METHODS: From January 2015 to January 2016, 115 patients with OVCFs who were scheduled to have a PKP were enrolled in this study. The factors analyzed included gender, age, body mass index (BMI), percentage of vertebral height loss, percentage of vertebral height restoration, number of fracture levels, bone mineral density (BMD), duration of symptom, cement leakage, and other internal diseases (hypertension, diabetes mellitus). According to Gross's formula, each patient's height, weight, and pre-operative and post-operative hematocrit were recorded and used for calculating the blood loss. Influential factors were further analyzed by multivariate linear regression analysis and t test.

RESULTS: The mean HBL was 282 ± 162 mL (mL) and the post-operative Hb loss was 8.7 ± 5.4 g per liter (g/L). According to multivariate linear regression analysis, patients with severe vertebral height loss (P = 0.016), better vertebral height restoration (P = 0.038), and multi-segmental vertebral fractures (P = 0.000) had a higher amount of HBL. Fresh fractures (P = 0.008) and cement leakage (P = 0.004) were also important factors to increase HBL, whereas gender (P = 0.642), age (P = 0.203), BMI (P = 0.075), hypertension (P = 0.099), diabetes mellitus (P = 0.905), and BMD (P = 0.521) were not correlate with HBL. When we compared the incidence of anemia between pre-operative and post-operative, we found that the incidence of anemia was significantly associated with HBL (P = 0.000).

CONCLUSIONS: HBL cannot be ignored in perioperative period, especially for poor physical condition and multiple fractures patients. Having a correct understanding of HBL can help improve clinical assessment capabilities, ensuring patients' safety.