A rare ultrasound finding in carpal tunnel syndrome
Mathieu Boudier-Reveret1, Meng-Ting Lin2, Chueh-Hung Wu2 1 Department of Physical Medicine and Rehabilitation, University of Montreal Health Center, Montreal, Canada 2 Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital, Taipei, Taiwan
Date of Submission
30-Mar-2019
Date of Acceptance
16-Apr-2019
Date of Web Publication
14-Jun-2019
Correspondence Address: Dr. Mathieu Boudier-Reveret Department of Physical Medicine and Rehabilitation, University of Montreal Health Center, 3840, St-Urbain St., Montreal, QC, H2W 1T8 Canada
Source of Support: None, Conflict of Interest: None
DOI: 10.4103/JMU.JMU_28_19
How to cite this article: Boudier-Reveret M, Lin MT, Wu CH. A rare ultrasound finding in carpal tunnel syndrome. J Med Ultrasound 2020;28:128-9
How to cite this URL: Boudier-Reveret M, Lin MT, Wu CH. A rare ultrasound finding in carpal tunnel syndrome. J Med Ultrasound [serial online] 2020 [cited 2023 Apr 1];28:128-9. Available from: http://www.jmuonline.org/text.asp?2020/28/2/128/285370
Section 2 – Answer
Case
A 60-year-old right-handed female presented with symptoms compatible with right carpal tunnel syndrome (CTS) for 1 year. Electrodiagnostic study confirmed the diagnosis of right CTS.
She was then referred to the physical medicine and rehabilitation (PM&R) ultrasound (US) clinic to receive US-guided perineural injection therapy of her right median nerve (MN) with 5% dextrose.
During the preliminary US scan of her right MN, a rare variant was found [Figure 1] and [[Figure 2] and Video 1]. She received the right MN perineural injection as planned [Figure 3].
Figure 1: Ultrasound of the right median nerve within the carpal tunnel, transverse axis. FCR: Flexor carpi radialis tendon, FDS: Flexor digitorum superficialis tendon, FDP: Flexor digitorum profundus tendon, FPL: Flexor pollicis longus tendon
This is the case of a 60-year-old female with CTS and an associated rare anatomical variant: a trifid MN.
Discussion
A retrospective study of 194 wrist magnetic resonance imagings performed for various reasons at one institution revealed only one case of trifid MN (0.5% prevalence), whereas the prevalence of bifid MN was 19% and 11% for persistent median artery.[1]
One case report of coexisting bifid and trifid MN s in a patient with bilateral carpal tunnel has been published.[2] Furthermore, a case of persistent median artery in association with a trifid MN has been described.[3]
Because so few cases have been reported in the literature, it is impossible to conclude as to whether this variant increases the risk of CTS. It remains important to recognize it, especially for a patient who will undergo carpal tunnel release surgery in order to properly decompress all three bundles.[4]
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Pierre-Jerome C, Smitson RD Jr., Shah RK, Moncayo V, Abdelnoor M, Terk MR, et al. MRI of the median nerve and median artery in the carpal tunnel: Prevalence of their anatomical variations and clinical significance. Surg Radiol Anat 2010;32:315-22.
Duymus M, Yilmaz O, Ulasli AM, Asal N, Kosar U. Coexistence of trifid and bifid median nerve in a patient with bilateral carpal tunnel syndrome. Turk Neurosurg 2013;23:685-7.
Cai H, Annaswamy TM. Trifid median nerve-A rare variant in a patient with carpal tunnel syndrome. Am J Phys Med Rehabil 2018. doi:10.1097/PHM.0000000000001057.
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