Risk Factors of Hidden Blood Loss in Unilateral Biportal Endoscopic Surgery for Patients with Lumbar Spinal Stenosis. - Guo, Sheng; Yu, Zhiyong; Wang, Chenglong; Zhong, Mingqiang; Wang, Rui; Hu, Yechang; Wang, Chunling; Li, Sen (Orthopaedic Surgery, 2024)