European Journal of Orthopaedic Surgery & Traumatology (2019) 29:1565–1574 https://doi.org/10.1007/s00590-019-02461-z

UP-TO DATE REVIEW AND CASE REPORT • WRIST -

Ulnar nerve entrapment in Guyon’s canal caused by a ganglion cyst: two case reports and review of the literature

Stylianos Tottas1 · Ioannis Kougioumtzis1 · Zafeiria Titsi1 · Athanasios Ververidis1 · Konstantinos Tilkeridis1 · Georgios I. Drosos1

Received: 20 March 2019 / Accepted: 3 June 2019 / Published online: 8 June 2019 © Springer-Verlag France SAS, part of Springer Nature 2019, corrected publication 2019

Abstract In this article, two cases of ulnar nerve neuropathy in Guyon’s canal caused by a ganglion cyst are reported. A review of the literature found 73 cases reported in 35 articles of at the wrist secondary to a ganglion cyst. We investi- gated the pathogenesis of ganglion cysts, which are separated as extraneural and intraneural. At this anatomical area, there are a variety of clinical factors that can also lead to ulnar nerve compression such us trauma, fracture of the hamate’s hook, arterial thrombosis, tumors and other anatomical variations. The symptoms may include weakness, , numbness and atrophy of hypothenar muscles. Except the careful clinical assessment, magnetic resonance imaging, ultrasound and electrophysiological control are useful tools regarding our diferential diagnosis. The treatment of this clinical condition is surgical. We consider that instant surgical decompression is of the essence and enables postoperatively total recovery. Level of evidence Level III.

Keywords Guyon’s canal · Ganglion · Ulnar entrapment · Ulnar neuropathy at wrist

Introduction the development of ganglions supports their formation due to mucoid degeneration [7]. On the other hand, concerning or compressive neuropathy is more the generation of intraneural ganglions, Spinner et al. [17] common at the elbow () followed by the wrist established the articular (synovial) theory which has been (Guyon’s canal) [1]. Guyon’s canal or ulnar tunnel is a widely accepted. There are several case reports concerning well-investigated anatomical region where ulnar nerve is the ulnar nerve compression by ganglion cyst at the Guyon’s susceptible to compression [2]. The causative factors of canal, but the clinical manifestation varies according to the ulnar neuropathy in Guyon’s canal include ganglions and area (zone) of the nerve compression by the ganglions cysts. tumors, anatomical variations, trauma, idiopathic reasons, We report two cases of ganglion cysts at the Guyon’s canal vessel malformations or overuse conditions [2–6]. Ganglions and a review of the literature concerning the types of gan- manifest themselves predominantly at the dorsal side of the glions and the clinical course including the diferent clini- wrist [7]. Ganglion cysts constitute the most frequent cause cal manifestations according to the area (zone) of the nerve of ulnar tunnel syndrome [8–11]. Ganglion cysts at the wrist compression by the ganglions cysts. usually stem from tendon sheaths or are related to degenera- tive arthritis [7]. However, ganglions may also occur within the epineurium of nerves, with mere few reported cases in Case reports the literature [12–16]. A widely known theory regarding Case 1

* Stylianos Tottas A 58-year-old right-handed woman visited our hospital’s [email protected] outpatient department, complaining for gradual weakness, 1 Orthopaedic Department, Medical School, University numbness and pain of the left hand for about 3-month General Hospital of Alexandroupolis, Democritus University period. She mentioned no history of trauma or other of Thrace, St. Niarhos 1, Dragana, 6810