Kerasnoudis Antonios
Dept. of Neurology, Ruhr University, St. Josef-Hospital, Gudrunstr. 56, 44791 Bochum, Germany.
Hand (N Y). 2012 Sep;7(3):333-4. doi: 10.1007/s11552-012-9435-z.
Carpal tunnel syndrome (CTS) is by far the most common entrapment neuropathy (Adams et al. Am J Ind Med 25:527-536, 1994; Cheadle et al. Am J Public Health 84:190-196, 1994; Stevens et al. Neurology 38:134-138, 1988). A combination of described symptoms, clinical findings and electrophysiological testing is used to confirm the diagnosis. Several studies have suggested that in patients with a clinical diagnosis of CTS, the accuracy of nerve sonography is similar to that for electromyography (Chen et al. BMC Med Imaging 11:22, 2011; Guan et al. Neurol Res 33:970-953, 2011; Kele et al. Neurology 61:389-391, 2003; Tai et al. Ultrasound Med Biol 38:1121-1128, 2012). In special cases though, the nerve sonography can reveal the cause of the median entrapment neuropathy (Fumière et al. JBR-BTR 85:1-3, 2002; Kele et al. J Neurosurg 97:471-473, 2002; Kele et al. Neurology 61:389-391, 2003; Zamora et al. J Clin Ultrasound 39:44-47, 2011).
A 43-year-old farmer was admitted to our department with 1 year of intermittent pain in the left hand and numbness of the thumb, index and middle finger. The pain and the numbness could be reproduced by extension of the wrist and fingers. The electrophysiological testing revealed signs of an entrapment median neuropathy in carpal tunnel.
The high-resolution sonography (18 MHz) revealed signs of entrapment neuropathy with increased cross-sectional area, disturbed echostructure of the nerve and pathological wrist-to-forearm ratio, confirming the results from a similar study (Kele et al. Neurology 61:389-391, 2003). In addition, an elongated muscle belly of the flexor digitorum superficialis in the carpal tunnel could be identified. During the extension of the wrist and fingers, a greater protrusion of the muscle belly could be demonstrated causing compression of the median nerve.
We present a video case report of the sonographic findings of a patient diagnosed with carpal tunnel syndrome due to an elongated muscle belly of the flexor digitorum superficialis in the carpal tunnel. Our case highlights the importance of nerve sonography in the differential diagnosis of the cause of a carpal tunnel syndrome. With the aid of ultrasonography, it is possible to obtain very important information concerning different aspects of this case. First, in showing the presence of the elongated muscle belly of the flexor digitorum superficialis, the cause of the symptoms could be explained. Second, it was possible through the ultrasound study to explain the atypical clinical appearance in this case, demonstrating the compression neuropathy only after extension of the wrist and fingers. There have been no previous reports in which authors described an elongated muscle belly as cause of a CTS. Third, and perhaps most important, ultrasonography had a direct influence on our selection of therapeutical strategy and approach. As a result, we recommended in this patient a surgical therapy to completely solve the problem, but the patient declined this option and preferred a conservative therapy with a hand orthosis to prevent wrist extension. In conclusion we recommend ultrasonography as a very useful method in the diagnostic evaluation of carpal tunnel syndrome. We have clearly demonstrated that ultrasonography can be used to discover the cause of median nerve compression, especially in cases with an atypical clinical presentation.
腕管综合征（CTS）是目前最常见的卡压性神经病（亚当斯等人，《美国工业医学杂志》25:527 - 536，1994年；奇德尔等人，《美国公共卫生杂志》84:190 - 196，1994年；史蒂文斯等人，《神经病学》38:134 - 138，1988年）。结合所描述的症状、临床检查结果和电生理测试来确诊。多项研究表明，对于临床诊断为CTS的患者，神经超声检查的准确性与肌电图相似（陈等人，《BMC医学影像学》11:22，2011年；关等人，《神经研究》33:970 - 953，2011年；凯莱等人，《神经病学》61:389 - 391，2003年；泰等人，《超声医学与生物学》38:1121 - 1128，2012年）。不过，在特殊情况下，神经超声检查可揭示正中神经卡压性神经病的病因（菲米埃等人，《比利时放射学与核医学杂志》85:1 - 3，2002年；凯莱等人，《神经外科学杂志》97:471 - 473，2002年；凯莱等人，《神经病学》61:389 - 391，2003年；萨莫拉等人，《临床超声杂志》39:44 - 47，2011年）。
一名43岁的农民因左手间歇性疼痛及拇指、示指和中指麻木1年入院。手腕和手指伸展时可再现疼痛和麻木症状。电生理测试显示腕管内存在正中神经卡压迹象。
高分辨率超声（18兆赫）显示存在卡压性神经病迹象，表现为神经横截面积增大、回声结构紊乱及腕部与前臂比值异常，证实了类似研究的结果（凯莱等人，《神经病学》61:389 - 391，2003年）。此外，可识别出腕管内指浅屈肌肌腹延长。手腕和手指伸展时，可显示肌腹有更大程度的突出，导致正中神经受压。
我们展示了一例因腕管内指浅屈肌肌腹延长而诊断为腕管综合征患者的超声检查结果视频病例报告。我们的病例突出了神经超声检查在腕管综合征病因鉴别诊断中的重要性。借助超声检查，能够获取有关该病例不同方面的非常重要的信息。首先，通过显示指浅屈肌肌腹延长，可解释症状的病因。其次，通过超声研究能够解释该病例非典型的临床表现，即仅在手腕和手指伸展后才出现压迫性神经病。此前尚无作者将延长的肌腹描述为CTS病因的报告。第三，或许也是最重要的一点，超声检查对我们治疗策略和方法的选择有直接影响。因此，我们建议该患者进行手术治疗以彻底解决问题，但患者拒绝了这一选择，更倾向于使用手部矫形器进行保守治疗以防止手腕伸展。总之，我们推荐超声检查作为腕管综合征诊断评估中一种非常有用的方法。我们已清楚证明，超声检查可用于发现正中神经受压的病因，尤其是在临床表现不典型的病例中。
