Buckland Aaron J, Beaubrun Bryan M, Isaacs Evan, Moon John, Zhou Peter, Horn Sam, Poorman Gregory, Tishelman Jared C, Day Louis M, Errico Thomas J, Passias Peter G, Protopsaltis Themistocles
Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, New York, NY, USA.
Asian Spine J. 2018 Feb;12(1):29-36. doi: 10.4184/asj.2018.12.1.29. Epub 2018 Feb 7.
Retrospective radiological review.
To quantify the effect of sitting vs supine lumbar spine magnetic resonance imaging (MRI) and change in anterior displacement of the psoas muscle from L1-L2 to L4-L5 discs.
Controversy exists in determining patient suitability for lateral lumbar interbody fusion (LLIF) based on psoas morphology. The effect of posture on psoas morphology has not previously been studied; however, lumbar MRI may be performed in sitting or supine positions.
A retrospective review of a single-spine practice over 6 months was performed, identifying patients aged between 18-90 years with degenerative spinal pathologies and lumbar MRIs were evaluated. Previous lumbar fusion, scoliosis, neuromuscular disease, skeletal immaturity, or intrinsic abnormalities of the psoas muscle were excluded. The anteroposterior (AP) dimension of the psoas muscle and intervertebral disc were measured at each intervertebral disc from L1-L2 to L4-L5, and the AP psoas:disc ratio calculated. The morphology was compared between patients undergoing sitting and/or supine MRI.
Two hundred and nine patients were identified with supine-, and 60 patients with sitting-MRIs, of which 13 patients had undergone both sitting and supine MRIs (BOTH group). A propensity score match (PSM) was performed for patients undergoing either supine or sitting MRI to match for age, BMI, and gender to produce two groups of 43 patients. In the BOTH and PSM group, sitting MRI displayed significantly higher AP psoas:disc ratio compared with supine MRI at all intervertebral levels except L1-L2. The largest difference observed was a mean 32%-37% increase in sitting AP psoas:disc ratio at the L4-L5 disc in sitting compared to supine in the BOTH group (range, 0%-137%).
The psoas muscle and the lumbar plexus become anteriorly displaced in sitting MRIs, with a greater effect noted at caudal intervertebral discs. This may have implications in selecting suitability for LLIF, and intra-operative patient positioning.
回顾性影像学分析。
量化坐位与仰卧位腰椎磁共振成像（MRI）的影响，以及腰大肌从L1-L2椎间盘至L4-L5椎间盘的前移变化。
基于腰大肌形态来确定患者是否适合进行腰椎侧方椎间融合术（LLIF）存在争议。此前尚未研究过体位对腰大肌形态的影响；然而，腰椎MRI可在坐位或仰卧位进行。
对一家脊柱专科机构6个月内的病例进行回顾性分析，纳入年龄在18至90岁之间、患有退行性脊柱疾病且接受过腰椎MRI检查的患者。排除既往有腰椎融合手术史、脊柱侧弯、神经肌肉疾病、骨骼未成熟或腰大肌先天性异常的患者。测量从L1-L2至L4-L5每个椎间盘水平的腰大肌和椎间盘的前后径（AP），并计算腰大肌与椎间盘的AP比值。比较接受坐位和/或仰卧位MRI检查患者的形态学差异。
共识别出209例接受仰卧位MRI检查的患者和60例接受坐位MRI检查的患者，其中13例患者同时接受了坐位和仰卧位MRI检查（两组均有组）。对接受仰卧位或坐位MRI检查的患者进行倾向评分匹配（PSM），以匹配年龄、体重指数（BMI）和性别，从而产生两组各43例患者。在两组均有组和PSM组中，除L1-L2外，坐位MRI在所有椎间盘水平的腰大肌与椎间盘AP比值均显著高于仰卧位MRI。观察到的最大差异是，两组均有组中，坐位时L4-L5椎间盘的腰大肌与椎间盘AP比值相比仰卧位平均增加32%-37%（范围为0%-137%）。
在坐位MRI检查时，腰大肌和腰丛向前移位，在尾端椎间盘处观察到的影响更大。这可能对选择LLIF的适用性及术中患者体位有影响。
