Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL.
Spine (Phila Pa 1976). 2017 Dec 15;42(24):E1386-E1392. doi: 10.1097/BRS.0000000000002303.
Retrospective imaging review.
Utilize magnetic resonance imaging (MRI) to expand the anatomical description of psoas morphology and its association with neurovascular structures at L4-5.
Anatomical psoas muscle variants may present a greater risk of neurovascular injury at the L4-5 level during lateral transpsoas approaches.
Axial L4-5 sections of consecutive patients who obtained lumbar MRIs were analyzed. Teardrop psoas morphology was assessed qualitatively. MRI described psoas morphology and proximity of neurovascular structures, whereas plain radiographs were evaluated for lumbosacral transitional vertebrae (LSTV). Teardrop morphology was tested for associations with radiographic measurements using t tests and χ analysis.
Fifty teardrop and 476 nonteardrop psoas muscles were identified. Teardrop morphology was associated with greater longitudinal length (53.1 vs. 49.3 mm, P = 0.012), and shorter transverse length (34.9 vs. 44.8 mm, P < 0.001) compared with nonteardrop. Teardrop morphology was associated with anterior and lateral migration of the psoas with greater distance between the anterior borders of the psoas and disc (13.5 vs. 6.3 mm, P < 0.001), and greater distance between the medial border of the psoas to the lateral disc border (1.6 vs. 0.5 mm, P < 0.001). Teardrop morphology was associated with a higher incidence of the lumbar plexus migrating anteriorly adjacent to the middle-third of the disc (43.4% vs. 17.6%, P < 0.001) and the iliac vasculature being more laterally and posteriorly located, adjacent to the anterior-third of the disc (43.4% vs. 30.0%, P = 0.047). Teardrop morphology was not associated with presence of LSTV (3.8% vs. 7.6%, P = 0.306).
The current study provides detailed metrics of teardrop psoas muscles and surrounding structures. The study confirms that the presence of teardrop anatomy on L4-5 axial imaging is associated with anterior migration of the lumbar plexus and posterolateral migration of the iliac vasculature which may increase the risk of neurovascular injury during direct and oblique-lateral lumbar spine procedures.
回顾性影像学研究。
利用磁共振成像（MRI）扩展腰 4-5 水平腰大肌形态及其与神经血管结构关系的解剖描述。
在侧方经椎间孔入路时，解剖学上的腰大肌变异可能会增加 L4-5 水平神经血管损伤的风险。
分析了连续接受腰椎 MRI 检查的患者的 L4-5 轴位切片。定性评估泪滴状腰大肌形态。MRI 描述了腰大肌形态和神经血管结构的毗邻关系，而 X 线平片则评估了腰骶移行椎（LSTV）。使用 t 检验和 χ 分析检验泪滴形态与影像学测量值的相关性。
共确定了 50 例泪滴状和 476 例非泪滴状腰大肌。与非泪滴状相比，泪滴状形态的腰大肌具有更长的纵向长度（53.1 与 49.3mm，P=0.012）和更短的横向长度（34.9 与 44.8mm，P＜0.001）。泪滴状形态与腰大肌的前向和侧向迁移有关，腰大肌前缘与椎间盘前缘之间的距离更大（13.5 与 6.3mm，P＜0.001），腰大肌内侧缘与椎间盘外侧缘之间的距离更大（1.6 与 0.5mm，P＜0.001）。泪滴状形态与腰椎丛向前迁移至椎间盘中三分之一附近的发生率较高有关（43.4%与 17.6%，P＜0.001），髂血管系统更靠近外侧和后部，毗邻椎间盘前三分之一（43.4%与 30.0%，P=0.047）。泪滴状形态与 LSTV 的存在无关（3.8%与 7.6%，P=0.306）。
目前的研究提供了泪滴状腰大肌及其周围结构的详细指标。该研究证实，L4-5 轴位成像上存在泪滴状解剖与腰椎丛的前向迁移和髂血管系统的后外侧迁移有关，这可能会增加直接和斜外侧腰椎手术中神经血管损伤的风险。
3。
