Ulnar intraneural cysts as a cause of cubital tunnel syndrome: presentation of a case and review of the literature.

Abstract

Intraneural cysts usually involve the common peroneal nerve, and in many cases, they are causing symptoms due to neural compression. It is hypothesized that these cysts originate from the adjacent joints while articular pathology is a major contributing factor for the formation of these lesions. Although ulnar nerve is the second most commonly affected nerve, these lesions usually develop distally at the Guyon tunnel, so cubital tunnel syndrome due to epineural cysts is very rare. In such cases, elaborate preoperative work-up is mandatory and surgical treatment should follow certain well-defined principles. A 60-year-old female patient presented with complaints of pain along the medial side of her elbow, forearm and hand and a tingling sensation in the same distribution for the past 2 months. The patient had sustained an injury 15 years ago, and a distal humerus fracture was diagnosed at that time. Radiological signs of posttraumatic elbow arthritis were evident at the initial evaluation. The patient was diagnosed with cubital tunnel syndrome which was further confirmed by nerve conduction studies, and she underwent surgical decompression of the nerve. During surgery, intraneural cysts were identified and addressed by excision, while dissection of the articular branch of the nerve was also performed. Pain and numbness subsided shortly after surgery, while the patient remained free of symptoms until the last follow-up.