Characteristics of surgically treated Guyon canal syndrome: A multicenter retrospective study.

Guyon canal (GC) syndrome is a rare peripheral neuropathy involving the distal part of the ulnar nerve. Several causes are associated with GC syndrome, including anatomic variations, space-occupying tumors, and trauma. Because of disease rarity, the only reported studies of GC syndrome are case series with small sample size. We conducted a multicenter study to identify the basic characteristics of patients with surgically treated GC syndrome and the risk factors for the disease. This retrospective multicenter study was conducted between January 2001 and December 2020. We screened 70 patients who underwent GC release surgery by seven hand surgeons at six institutes. A total of 56 patients were included in this study, including 38 patients (67.9%) who underwent isolated GC decompression and 18 (32.1%) who underwent combined peripheral nerve decompression. The mean patient age was 48.4 years (range: 20-89 years), and 40 patients (71.4%) were male. The average preoperative symptom duration was 18.5 months, and most patients were office workers. Ultrasound was positive for GC syndrome in 7/10 patients evaluated, CT in 2/5, MRI in 17/23, and electrodiagnostic studies in 35/44. The most common cause of GC syndrome was tumor (n = 23), followed by idiopathic (n = 17), trauma (n = 12), anatomic variants (n = 3), and inflammation (n = 3). In conclusion, most patients with GC syndrome in this study were male and had symptoms in one wrist. The most common cause of GC syndrome in this study was a tumor, including a ganglion cyst. Level of Evidence: Level IV case series.