股外侧皮神经超声检查——文献综述和图片展示（二）

 英语晨读 ·

山东省立医院疼痛科英语晨读已经坚持10余年的时间了，每天交班前15分钟都会精选一篇英文文献进行阅读和翻译。一是可以保持工作后的英语阅读习惯，二是可以学习前沿的疼痛相关知识。我们会将晨读内容与大家分享，助力疼痛学习。

本次文献选自Becciolini M, Pivec C, Riegler G. Ultrasound of the Lateral Femoral Cutaneous Nerve: A Review of the Literature and Pictorial Essay. J Ultrasound Med. 2022 May;41(5):1273-1284.本次学习由陈阳主治医师主讲。

US Technique to Study the Normal LFCN and Pathological Findings in MP

Before starting the US examination, we review the clinical indication for the exam and previous diagnostic tests. Since not all patients are referred with a suspicion of MP, we have a brief medical history and clinical examination, in which patients are particularly asked about previous trauma and/or surgery along the course of the LCFN.

研究正常LFCN和MP病理情况的超声技术

在开始超声检查之前，应熟悉检查的临床适应症和之前的诊断测试。由于并非所有患者都被怀疑患有MP，应进行简短的病史采集和临床检查，特别要询问患者在LCFN走行区域的既往创伤和/或手术情况。

Even when the clinical suspicion of MP is high, a quick US assessment of the anterolateral hip is performed and possible differential diagnoses are ruled out, for example, greater trochanter pain syndrome, hip joint arthropathy, femoral neuropathy, iliac mass then, the examination is focused on studying the course of the LCFN.

即使临床高度怀疑MP的情况下，也应对前外侧髋关节进行快速超声评估，并排除可能的鉴别诊断，例如，大转子疼痛综合征、髋关节关节病、股神经病变、髂肌肿块，然后，检查重点是扫查LCFN的走行全程。

The patient lies supine. We start the US exploration with a linear multifrequency transducer with frequencies up to 12 or 15 MHz, and a footprint of around 5 cm to provide a large view of the area. Then, we focus the examination with a higher frequency transducer (≥18 MHz) with a smaller footprint to better delineate the anatomy of the LFCN; however, in obese patients, the higher frequency may be not useful due to the increased thickness of the subcutaneous fatty tissue.

病人仰卧位。我们使用了频率高达12或15 MHz的线性探头开始超声扫查，深度设置为5cm以提供该区域的大视野。然后，我们使用深度较小的高频换能器（≥18MHz）聚焦检查，以更好地显示LFCN的解剖结构；然而，在肥胖患者中，由于皮下脂肪组织的厚度增加，较高的频率可能是无用的。

The easiest way to locate the LFCN is to start with axial sonograms caudal to the level of the ASIS, which can be palpated. The tensor fasciae latae and sartorius muscles are easily depicted, superficial to the proximal tract of the rectus femoris. The fat canal bounded by two fascial layers can be demonstrated superficial to these two muscles. Inside this fat canal, the LFCN can be located: due to the small size of the nerve, it appears as small honeycomb structures on axial planes (Figure 2A), which can be followed up and down using the elevator technique through continuous scanning. Usually, we do not study the course at the distal thigh of the LFCN, unless it is clinically relevant (e.g., in case of a wound of the distal anterolateral thigh).

定位LFCN的最简单方法是从ASIS水平的尾部轴向超声图开始。阔筋膜张肌和缝匠肌很容易被显示出来，位于股直肌近端束的表面。由两个筋膜层包围的脂肪管可以显示在这两块肌肉的表面。脂肪管内可以定位LFCN：由于神经较小，它在轴向平面上表现为小蜂窝结构（图2A），可以使用升降机技术通过连续扫描进行上下跟踪。通常，我们不研究LFCN在大腿的走行，除非它与临床相关（例如，大腿前外侧受伤）。

The nerve is tracked proximally at the level of the ASIS. We suggest orienting the probe along the course of the IL, as this maneuver has the advantage of better demonstrating the relationship of the LFCN to the IL and ASIS, which are, in our experience, the main sites of the compressive neuropathy. Moreover, this allows detection of the correct short axis of the LFCN (Figure 2B).

神经在ASIS水平进行近端扫查。我们建议探头与IL平行，因为这种方式能更好地表现LFCN与IL和ASIS的关系，根据我们的经验，这是压迫性神经病变的主要部位。此外，该方式也能检测LFCN的正确短轴（图2B）。

In the pelvis, the nerve may be difficult to be further tracked, particularly in obese patients. In slender subjects, it can usually be detected until it is crossed by the DCIV, located anterior to the iliacus muscle. Color Doppler enables discrimination between the nerve and the vessels (Figure 3A and D). Proximal to the DCIV, the course deep to the psoas major muscle and the LFCN origin is almost blind to US; this is related to the loss in resolution when imaging deep small structures. The structures of the anatomically described “aponeuroticofascial” tunnel just before the IL are difficult to be clearly differentiated at US because fascial planes are contiguous.

在骨盆，神经可能很难被进一步追踪，特别是在肥胖患者中。在苗条的受试者中，通常可以探测到它，直到它被位于髂肌前方的DCIV穿过。彩色多普勒能够区分神经和血管（图3A和D）。在DCIV的近端，深至腰大肌和LFCN起点的走行超声难以企及；这与成像深小型结构时的分辨率损失有关。就在IL之前的解剖学描述的“腱膜神经筋膜”隧道的结构在超声下很难明确区分，因为筋膜平面是连续的。

The US features of entrapment neuropathies are swelling with a more hypoechoic appearance of nerve fascicles (“neuromatous appearance”), which can be demonstrated during the aforementioned elevator technique (Figure 3). When nerve disorders are depicted, we suggest acquiring a longitudinal sonogram of the LFCN to demonstrate the neuroma location and to possibly measure its craniocaudal extension (Figure 3D).

卡压性神经病变的超声特征是肿胀，神经束表现为较低回声（“神经瘤样表现”），这可以在上述电梯技术中得到证明（图3）。当描述神经疾病时，我们建议获取LFCN的纵向超声图，以显示神经瘤的位置，并可能测量其颅尾延伸（图3D）。