Carpal Tunnel Syndrome
The carpal tunnel is a tight tunnel at the front of the wrist formed by the carpal (wrist) bones and a wide ligament called the transverse carpal ligament. Through this limited space run all 9 flexor tendons to the fingers as well as the median nerve, one of the 2 major nerves to the hand.
Carpal Tunnel Syndrome is an entrapment neuropathy of the median nerve at the wrist. This simply means; as the nerve runs through the carpal tunnel, for whatever reason there is a lack of space, causing intermittent neurological symptoms which include numbness, paraesthesia (pins and needles), pain and weakness and potentially in late stages it can cause permanent nerve damage resulting in worsening of hand function.
Carpal Tunnel Syndrome is extremely common, affecting
up to 10% of the population and affects both hands in
more than 50% of sufferers. It can be related to trauma, inflammatory conditions, diabetes or pregnancy. These
are all conditions that increase swelling and therefore
result in less space in the carpal tunnel. Similarly,
repetitive extreme wrist flexion and extension during
sporting activities or work can contribute to symptoms,
but in the majority (95%) there are no contributing factors or causes.
The most common symptoms, which are almost universal, are nocturnal numbness and paraesthesia disturbing sleep. Classically symptoms are mainly on the thumb side of the hand but they can radiate through the whole hand and arm. Symptoms may be worse at night for a combination of reasons; there is a tendency towards wrist flexion when sleeping (increases carpal tunnel pressure), blood pressure normally drops (decreases nerve blood flow) and lying down redistributes fluid to the upper limbs.
Symptoms can progress to the daytime including weakness and clumsiness of the affected hand, dropping things during normal activity and may therefore begin to affect sporting performance.
An experienced doctor or physiotherapist can often make the diagnosis, but if symptoms are atypical, Nerve Conduction Studies may be necessary to confirm the diagnosis and exclude another cause (such as nerve problems from the neck).
Treatment is initially non-operative unless symptoms are severe. This consists of activity modification, a night splint, simple pain relief including Non Steroidal Anti-Inflammatory Drugs (eg. Voltaren) and often a steroid injection into the carpal tunnel. The night splint should be custom made by a Physio or Hand Therapist with the wrist in a neutral position. ‘Off the shelf’ splints usually place the wrist in extension, which increases pressure in the carpal tunnel and can therefore worsen symptoms rather than relieving them. The steroid injection works by decreasing inflammation around the nerve and therefore decreasing swelling in the tunnel and relieving symptoms. If symptoms are mild this treatment is often successful.
If non-operative treatment fails or symptoms are more severe then surgery may be necessary. This consists of cutting the transverse carpal ligament and therefore opening the carpal tunnel space. Surgery is simple and generally very successful but should be performed by a surgeon with an understanding of the many complex variations of the median nerve and its branches, to decrease the risk of complications.
The standard form of surgery is Open Carpal Tunnel Release, which involves an incision on the palm and then release of the ligament until the nerve is visualized and free from pressure. As an alternative, Endoscopic Carpal Tunnel Release involves using a camera to release the same ligament through either 1 or 2 small incisions. This technique is considered as safe and effective as open surgery when performed by surgeons properly trained in the technique. If during surgery, the view with the endoscopic camera is inadequate, then the surgeon can still proceed to open surgery.
There is generally a quicker recovery and less pain after endoscopic surgery because of smaller wounds and less scar formation. This may mean a quicker return to sport or heavy work though it is important to realize there is no difference in the long term outcome.
I perform either open or endoscopic carpal tunnel surgery depending on patient preference and surgical indication. This is performed as Day Surgery under Local Anaesthetic and Sedation, which avoids the risks and longer recovery from a General Anaesthetic. For endoscopic surgery I use the 1 incision technique using the MicroAire SmartRelease endoscopic system, which avoids any palm wound or scarring.