Treatment of Failed Carpal Tunnel Syndrome by Dorsal Ulnar Artery Perforator Adipofascial Flap

Overview

Carpal tunnel syndrome (CTS) is the most common compressive neuropathy in the general population. Surgical treatment by open or endoscopic carpal tunnel release (CTR) is the first choice of treatment and has clinical success rates of 75% to 90%.The rate of recurrence after primary median nerve release is 3-19% \[1,2\]. Between 0.3% and 12% of cases require surgical revision \[2,3\]. The risk factors for surgical revision for secondary release are male gender, staged or simultaneous bilateral carpal tunnel release, endoscopic release, smoking and rheumatoid arthritis. Treatment failures after primary CTR are classified as persistent CTS, recurrent CTS, or new symptoms. Recurrent symptoms are uncommon and are defined by a symptom-free interval after surgery. Persistent symptoms are relatively common, particularly in elderly patients and in patients with concurrent nerve compression or medical conditions that affect nerve function, such as diabetes. Persistent or recurrent CTS principally results from incomplete release of the transverse carpal ligament but may be accompanied by perineural scarring, leading to compression or tethering of the median nerve. New symptoms may be caused by iatrogenic nerve injury. Surgical treatment of recurrent or persistent CTS after primary CTR usually involves open revision CTR, extended proximally into unscarred tissue, and has also included internal or external neurolysis. Unsatisfactory results following revision CTR are common. A second compression site, or double-crush syndrome, may clinically present as RCTS or PCTS . Thorough preoperative clinical examination may uncover signs of a second compression site, which can then be confirmed on electroneuromyography (ENMG) of the entire arm. To improve outcomes of revision CTR, recent studies have emphasized the importance of median nerve coverage by well-vascularized soft tissue to enhance nerve healing, to prevent tethering in surrounding scar tissue, and to optimize nerve gliding in the carpal tunnel. Several local flaps (hypothenar fat pad flap, tenosynovial flap), regional flaps (posterior interosseous artery flap, reverse radial artery fascial flap, flexor digitorum superficialis flap), and free flap techniques have been described, but consensus for specific flap has not been reached. Following potential iatrogenic median nerve injury and reexploration for a painful neuroma incontinuity, flap coverage may also be beneficial. In 1988, Becker and Gilbert introduced a Fasciocutaneous pedicled flap based on a consistent dorsal perforator of the ulnar artery (absent in 1 % of population) named the dorsal ulnar artery (DUA) flap or simply the Becker flap. The authors described open revision CTR with nerve coverage by a DUA flap in 3 patients with recurrent CTS and reported good results as well as a quick and easy-to-perform dissection with low donor site morbidity and preservation of the radial andulnar artery. Since this introduction, additional studies describing fasciocutaneous DUA flaps have mostly focused on its use for reconstruction of hand or wrist wounds. Despite the original described benefits, additional studies of DUA flaps for the treatment of recurrent or persistent CTS have remained limited.