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:

• Numbness and tingling in the hand; typically these symptoms are present in the thumb, index and middle fingers.
• Some patients may experience an electrical shock sensation.
• Weakness of grip may be experienced. Patients may even notice they are dropping small objects more frequently.
• Usually, the symptoms will first occur at night, with numbness, pain, and tingling waking patients up. As carpal tunnel syndrome progresses symptoms become present during the day.

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.

• Radiographs/X-rays: These may be ordered to rule out other causes of wrist pain.
• Electromyography (EMG) / Nerve conduction study (NCS): The EMG/NCS, sometimes referred to as electrodiagnostic tesing, measures electrical signals transmitted along nerves and the tiny electrical discharges produced in the muscles of the arm and hand. In carpal tunnel syndrome, the median nerve is compressed causing the electrical impulses to diminish and slow down through the carpal tunnel. An EMG/NCS performed in the office and can be coordinated through our office.
• Ultrasound (US): A diagnostic ultrasound can also be used to diagnose carpal tunnel syndrome. Ultrasound visualizes the median nerve, and when the nerve is entrapped it appears enlarged. The size of the median nerve at the wrist and forearm predicts the severity of carpal tunnel disease as accurately as EMG/NCS. The dynamic nature of ultrasound also allows the provider to identify impingement that may be related to motion that may otherwise be missed on MRI or EMG/NCS (Cartwright, et al., 2012).

The first line of defense is always the least invasive treatment. In this case, when a CTS diagnosis is made early, many patients find relief of their symptoms with conservative treatments, such as the use of a neutral wrist brace or a workplace ergonomic adjustment.

• Activity Modification: Certain lifestyle changes can reduce pressure on the wrist. Proper wrist position while using a computer, including keeping the wrists straight or in a neutral position using padding to support the wrist, minimizing repetitive hand movements, adding small breaks throughout the day and alternating between activities or tasks can reduce strain on the wrist.
  
• Bracing: Wearing a wrist brace or splint when sleeping holds the wrist in a neutral position to relieve numbness and tingling.
  
• Nonsteroidal anti-inflammatory drugs (NSAIDs): May reduce pain and symptoms of carpal tunnel syndrome, although may not resolve or reverse carpal tunnel syndrome.
  
• Corticosteroid injections: Cortisone injections can relieve pain from carpal tunnel syndrome by decreasing inflammation. Injections are more effective than oral corticosteroids, but about half of patients will require additional treatments within one year (Marshall et al., 2007; Huisstede et al. 2012;. Jarvik et al., 2009). Ultrasound-guided carpal tunnel injections have been shown to achieve better results when compared to "blind" injections where no image guidance was used (Farfour et al., 2023)
  
• Nerve Hydrodissection: Ultrasound-guided nerve hydrodissection is based on the theory that nerve entrapment is exacerbated when the median nerve adheres to the transverse carpal ligament. The nerve hydrodissection procedure involves injecting lidocaine and saline around the nerve to create space between the nerve and surrounding tissue to improve nerve mobility (Evers et al., 2019). The ultrasound guidance decreases chances of median nerve injury compared to "blind" injections, and makes this a safe procedure that can be performed in the office.
  
• Platelet Rich Plasma (PRP): Platelet Rich Plasma injections have been compared to various conservative treatments for carpal tunnel syndrome [Catapano et al, 2020; Dong et al, 2020; Malahias et al, 2019]. While corticosteroids consistently had short-term benefit over PRP injections, longer term data shows PRP has better symptom relief [Catapano et al, 2020; Dong et al, 2020; Malahias et al, 2019].
  

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 (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]

What can I expect after the Ultrasound-Guided Carpal Tunnel Release?

• The hand will be numb from the local anesthesia, but you are encouraged to use the hand immediately after the procedure.
• The 2-4 mm incision will be covered with bandages to keep on for the first day. There will be no sutures.
• Most patients can resume usual normal activities and return to work within 3-6 days.
• Post operative discomfort is typically managed with Tylenol or NSAIDs as necessary.
• Most patient do not require any physical or occupational therapy.

What are the risks/complications?

• With any invasive procedure, there is always a risk of infection, treatment failure, incomplete relief, or neurovascular injury. Some patients experience palm pain (pilar pain) after the procedure, and this typically resolves over weeks or months
• The use of ultrasound for pre-procedure screening as well as guidance during the procedure reduces these risks.
• Recent publications on this procedure report equal success to traditional surgery, with better postoperative pain and sensitivity [Eberlin 2023]

How long has this procedure been used?

• This procedure was developed in 2014 by physicians at the Mayo Clinic
• The first carpal tunnel release using UltraGuideCTR developed by Sonex with real-time ultrasound guidance was performed February 17, 2017
• More than 90 different physician users offer this in 25 different states
• Dr. Sussman has been performing this procedure since 2021 and Dr. Latzka since 2023