Carpal tunnel syndrome (CTS) occurs when the median nerve is compressed as it travels through the carpal tunnel in the wrist, causing pain, numbness, weakness and tingling in the hand. The carpal tunnel is a canal on the palm side of the wrist. The tunnel is formed by carpal bones (floor) and the transverse carpal ligament (roof). Within the canal there are: 1) nine tendons that connect the muscles in the forearm to bones of the hand/fingers; and 2) the median nerve. The median nerve is one of the major nerves in the hand that controls feeling and movement in the thumb, index, and long fingers.
Carpal tunnel syndrome is the most common nerve entrapment syndrome in humans, with an incidence of 3.5-6.2% (Nordstrom et. al., 1998). The incidence is highest among middle-aged and elderly women. Carpal tunnel syndrome affects more than 12 million Americans and can be associated with high social and economic costs. Carpal tunnel release (CTR) is the most common hand and wrist procedure performed in the United States, with an estimated 400,000 patients undergoing open or endoscopic surgery every year.
Patients will often report:
Carpal tunnel syndrome is typically a clinical diagnosis, based on a detailed history and physical exam. The following tests can be ordered as part of your workup to confirm the diagnosis.
In severe cases, where symptoms do not respond to non-surgical treatment, surgery has been shown to be an effective method for treating carpal tunnel syndrome. Various techniques have been shown to be effective, with no single technique deemed superior based on the current evidence [Pace et al, 2023]. However these techniques have specific advantages and disadvantages, and should be taken into account when choosing among the surgical methods.
Open Carpal Tunnel Release: An open carpal tunnel release uses a traditional incision or mini-incision along the distal wrist crease. The most common length of the traditional incision is 5 cm and mini-incision is 2 cm. [Pace et al, 2023]. The incision is extended through the palmar fat and fascia, and then the transverse carpal ligament is completely split longitudinally. The wound is closed with stitches.
Open carpal tunnel release has been reported to be safe overall, but complications include wound infection, nerve injury and scar formation, especially using a traditional size incision.
Endoscopic carpal tunnel release: The endoscopic carpal tunnel release uses a single or two-portal approach, and was first introduced in 1986 [Okutsu et al, 1986]. The endoscopic technique uses a small camera to look into the carpal tunnel and cut through the transverse carpal ligament.
The endoscopic carpal tunnel release has good reported outcomes with a low complication rate and better esthetic results due to the smaller scar.
Ultrasound-Guided Carpal Tunnel Release: Ultrasound-Guided carpal tunnel release (US-CTR) uses ultrasound to visualize the median nerve and transverse carpal ligament, and perform the release. The ultrasound-guided approach has been shown to have a low complication rate and fast recovery. [Sanati et al, 2011; Chou et al, 2022; David, 2022; Moungondo and Feipel, 2022].
The Sonex SX-One MicroKnife is a new, cutting-edge device designed to further improve the success and the safety of ultrasound guided carpal tunnel releases. The procedure is performed using only local anesthetic and is inserted through a 2-4 mm incision (compared to 20-50 mm in open surgery). The device deploys miniature balloons to protect important structures and increase the space for the knife to transect the transverse carpal ligament. These balloons and the proprietary cutting device prevent unintended injury to nearby neurovascular structures and adjacent soft tissue which could prolong recovery.
In a recent ground breaking study, titled “Multicenter Randomized Trial of Carpal Tunnel Release with Ultrasound Guidance versus Mini-Open Technique,” orthopedic hand surgeon Dr. Kyle Eberlin (Program Director, Harvard Plastic Surgery Residency Program, and Associate Program Director, MGH Hand Surgery Fellowship) found that USG-CTR performed equally to the mini-open surgical carpal tunnel release. The authors found no statistical differences between the groups, except they did find that USG-CTR group reported “freedom from pain and wound sensitivity” in 61% of patients, compared to in only 18% of mini-open CTR patients.[Eberlin 2023]
Zhang S, et. al. Cost-minimization analysis of open and endoscopic carpal tunnel release. J Bone Joint Surg Am 2016;98:1970-7.