分析单通道全脊柱内镜下单侧入路椎板切开双侧减压技术(uniportal full-endoscopic unilateral laminotomy for bilateral decompression，UFE-ULBD)治疗腰椎管狭窄症(lumbar spinal stenosis，LSS)的隐性失血情况及其危险因素。

回顾性分析2021年8月至2023年6月期间于首都医科大学附属北京友谊医院骨科中心因单一节段LSS接受UFE-ULBD手术的患者。收集患者一般资料如年龄、性别、身体质量指数、吸烟饮酒史、内科合并症、术前贫血情况、美国麻醉师协会体格情况分级，手术资料如手术节段、手术节段椎管狭窄Schizas分型、麻醉方式、手术时间、术中晶体液/胶体液输注量，以及测量手术节段椎旁肌厚度比例、关节突关节切除角度、盘黄间隙减压率、骨性侧隐窝减压率、上关节突内侧间距及扩大率、椎板中点间距及扩大率、硬膜囊横截面积及扩大率等影像学参数。

共纳入56例患者(男26例，女30例)，平均手术时间97.2±45.2 min，平均总失血量235.0±188.5 ml，平均隐性失血量190.7±184.3 ml，占总失血量66.1%。将患者分为隐性失血阳性组(隐性失血≥470 ml)与隐性失血阴性组(隐性失血<470 ml)。两组患者在手术节段的术前椎板中点间距(P＝0.002)、术后椎板中点间距扩大率(P＝0.021)、术前硬膜囊横截面积(P＝0.009)以及术后硬膜囊横截面积扩大率(P＝0.013)等存在差异。Logistic回归分析提示手术节段术后硬膜囊横截面积扩大率(OR＝3.889，P＝0.042)是隐性失血的潜在危险因素。

UFE-ULBD治疗LSS存在较为显著的隐性失血情况，患者手术节段术后硬膜囊横截面积扩大率是隐性失血的潜在危险因素。

To investigate the hidden blood loss (HBL) and risk factors of uniportal full-endoscopic unilateral laminotomy for bilateral decompression (UFE-ULBD) for patients with lumbar spinal stenosis (LSS).

Patients with single-segment LSS who underwent UFE-ULBD from a single orthopedic center were retrospectively analyzed between Aug.2021 and Jun.2023. The general data of patients such as age, gender, body mass index, history of smoking and drinking, medical comorbidities, preoperative anemia, American Society of Anesthesiologists physical status classification; surgical data such as surgical segment, Schizas classification of spinal stenosis, anesthesia method, operation time, intraoperative crystal fluid/colloid infusion volume; and radiological parameters such as paraspinal muscle ratio, angle of facetectomy, decompression ratio of disc-flava ligament space, decompression ratio of osseous lateral recess, superior articular process interval enlargement ratio, lamina interval enlargement ratio, dural sac cross-sectional area and enlargement ratio were also measured.

Fifty-six patients (26 males and 30 females) were retrospectively enrolled in this study. The mean operation time was 97.2±45.2 minutes, the mean total blood loss was 235.0±188.5 ml, and the mean HBL was 190.7±184.3 ml, accounting for 66.1% of total blood loss. These patients were divided into HBL positive group (HBL≥470 ml) and HBL negative group (HBL<470 ml). There were significant differences between the two groups in preoperative bilateral lamina interval (P=0.002), postoperative bilateral lamina interval enlargement ratio (P=0.021), preoperative dural sac cross-sectional area (P=0.009) and postoperative dural sac cross-sectional area enlargement ratio (P=0.013) at the surgical level. Logistic regression analysis suggested postoperative dural sac cross-sectional area enlargement ratio at the surgical level (OR=3.889, P=0.042) was the potential risk of HBL.

HBL was significant in LSS patients who underwent UFE-ULBD. And postoperative dural sac cross-sectional area enlargement ratio at the surgical level might be potential risk of HBL.