Straight Dope on Medicine: Carpal Tunnel

Author

Scott Ganser
March 17, 2024

Carpal tunnel syndrome (CTS) is the most frequently encountered mononeuropathy in clinical practice. Although now a well–recognized entity, it took almost 100 years from the initial observations until the pathophysiology of the disorder was finally accepted as a median nerve compression at the wrist.

Sir James Paget (1854) was the first to describe the clinical features of CTS. His first patient was a man who developed pain and impaired sensation in the hand from the trauma of a cord drawn tightly around his wrist. In a second case, a tardy median nerve palsy was a consequence of a distal radius fracture; this patient improved with wrist immobilization and thus was also the first description of treatment with a neutral wrist splint, a method still in use today.[i]

Carpal Tunnel Syndrome (CTS) is the most common compression neuropathy of the upper extremities. The first case documented by Sir James Paget in 1854 describes a patient who had a rope tied tightly around his wrist and experienced such unrelenting pain and parasthesia that he required an amputation. Fortunately, modern day CTS treatments are less drastiThe term “Carpal Tunnel Syndrome” was coined in 1938 by the neurologist Moersch. It did not become a well-defined clinical entity until George Phalen began his work in the 1950s. Phalen examined hundreds of hands afflicted with a similar constellation of symptoms and concluded that:

“The median nerve is easily compressed by any condition that increases the volume of the structures within the carpal tunnel.”[ii]

Fast forward to the present day. CTS is now treated successfully with a variety of non-operative and operative means. Nighttime splinting is a good first line of treatment for people who are experiencing a numb and tingly hand and have trouble sleeping at night. Glucocorticoid injections also work. Some people opt for acupuncture or electrotherapy. Splints aim to keep the wrist out of the flexed position that can compress the median nerve and produce painful symptoms.

Anticipated relief typically lasts for about 3 months.

For each wrist, it is advisable to limit injections to a maximum of every 6 months.

For those select patients who find that non-operative treatments do not work or those who immediately present with advanced neuropathy, a surgical approach may be considered. Incising the ligament (which is the roof of the carpal tunnel) has proven to be a very effective treatment. While this procedure was initially performed as an “open procedure” through a 4 to 5 centimeter incision, mini-open and endoscopic alternatives are now offered. The primary advantages of these less invasive techniques are a faster recovery and excellent results.

Some individuals who undergo surgery gain grip and pinch strength 2 to 3 months later, but some people don't notice improvement until 6 to 12 months after surgery. However, 90 percent of patients find that surgery provided long-lasting relief from common symptoms of CTS.

Surgery is improving as we speak, with the development of new devices, the traditional open treatment is gradually being replaced by minimally invasive techniques with shorter operative times, less trauma, smaller postoperative scars and shorter incision healing times.[iii] 

Who gets Carpal Tunnel?

The incidence of CTS in the general population ranges from 1% to 5%. CTS is more prevalent in females than males, with a 3:1 female-to-male ratio. The risk of developing CTS is doubled in individuals who are obese. CTS is uncommon in children and typically manifests in adults aged 40 to 60.[iv]

CTS impacts 4 to 10 million Americans, according to the Rheumatology Research Foundation.[v]

Approximately 50 percent of CTS risk is determined by heredity.

Diagnosis

In carpal tunnel syndrome, the pain or paresthesia is usually felt in the wrist, the palm, and the first four fingers of the hand. These signs and symptoms often develop during sleep and are noticeable upon waking. Affected individuals typically shake their hand to get rid of the pain and numbness, a characteristic move known as the flick sign. As the condition advances, the signs and symptoms begin to occur during the day as well. Affected individuals may have difficulty performing manual tasks such as turning doorknobs, fastening buttons, or opening jars. The symptoms of carpal tunnel syndrome may be triggered by certain activities that flex or extend the wrist, such as driving, typing, or holding a telephone.[vi]

The most dependable provocative maneuver, known as the carpal compression test, involves applying steady pressure directly over the carpal tunnel for 30 seconds. A positive test is evident when paresthesias or pain arises within the median nerve distribution during the carpal compression test. This test is associated with a sensitivity of 64% and a specificity of 83%.

The Phalen test, also known as the reverse prayer, involves instructing the patient to fully flex their wrists by placing the dorsal surfaces of both hands together, with the elbows flexed, and holding this position for 1 minute. A positive test is marked by pain and paresthesias in the fingers innervated by the median nerve during the Phalen test. This test exhibits a sensitivity of 68% and a specificity of 73%.

Patients unresponsive to conservative treatments or those with severe CTS confirmed through electrophysiological testing may require surgical intervention. Electrophysiological testing is a prerequisite for carpal tunnel release surgery, which serves as the definitive treatment for CTS and can be performed using an open or endoscopic approach. This minimally invasive procedure relieves pressure on the median nerve by making a small incision in the transverse carpal ligament. Patients can often be discharged on the same day without staying overnight in the hospital.

In general, surgery offers more favorable long-term outcomes compared to conservative therapy. Although initial success rates surpass 90%, long-term results are somewhat less promising, with an approximate success rate of 60% at the 5-year mark.

Complications

Complications of CTS can arise from the condition itself or the treatments administered. CTS may lead to irreversible median nerve damage, resulting in permanent impairment and disability. Muscle weakness and atrophy at the base of the thumb can cause reduced dexterity. Patients affected by this condition may also suffer from chronic wrist and hand pain, potentially progressing to the development of complex regional pain syndrome.

The most frequent complication of carpal tunnel surgery is the development of a neuroma in the palmar cutaneous branch of the median nerve. Patients may also experience hypertrophic scars, joint stiffness, dysesthesias, and incomplete resolution of their symptoms.

These stats are for Carpal Tunnel Release.

Carpal tunnel release is a minimally invasive surgery that can ease pain and increase mobility in your hands and wrists. But not all hospitals achieve the same results. Some are more reliable than others. With the help of the HSS Hospital Reliability Scorecard, you can make sure you're asking the critical questions to find the hospital that's right for you. Understanding the data points linked here will help you make the best decision for your care: See hospital reliability data

The Costs

Carpal tunnel syndrome (CTS)is an extremely common and costly upper extremity condition that accounts for over $2 billion in medical costs annually in the United States. In addition to causing pain and numbness, CTS causes individuals to miss an average of 27 days of work from the onset of the condition to its final treatment.[vii]

Risk Factors

  • Being female

  • Individuals who are middle-aged (40 to 60 years old)

  • Occupations with repetitive hand movements or prolonged exposure to vibration

  • People with obesity

  • Individuals who are pregnant, using oral contraceptives, or who have undergone menopause

  • People with chronic health issues like diabetes, alcoholism, congestive heart failure, kidney failure, vitamin deficiency, or hypothyroidism (underactive thyroid)

 Carpal tunnel syndrome in both hands is concerning

“If you have it in both hands, you need to be worried about something going on in your neck or something else like hypothyroidism or diabetes—some of the more dangerous causes—rheumatoid arthritis,” Dr. Kramer said. “So, in two hands, as a patient you need to be more concerned and that needs to be more of a red flag for you that it’s time to get something looked at.

“If you have neck pain and numbness and tingling in both your hands, get that looked at,” he added.[viii]

Mayo Clinic

Carpal tunnel syndrome is common, and an estimated 71% of patients receive surgical intervention as their primary treatment.

The goal of carpal tunnel release surgeries is to decompress the median nerve by dividing the transverse carpal ligament (TCL). The two most common surgical interventions are open carpal tunnel release (OCTR) and endoscopic carpal tunnel release (ECTR). Endoscopic approaches are usually associated with less postoperative pain and a faster return to work, but also with increased risk of nerve injury and incomplete release.

Mayo Clinic is one of the few hand centers that offer ultrasound-guided intervention for carpal tunnel release. A newer, incisionless treatment release — known as thread ultrasound-guided carpal tunnel release (TCTR) — uses an abrasive thread looped percutaneously to dissect the TCL and is performed using local anesthesia.[ix]

Technique

Step 1

Step 2

Step 3

Step 4

Step 5

TCTR is designed to minimize soft tissue dissection and injury, decrease pillar pain, and accelerate recovery. In their article and accompanying video, Drs. Brault and Shin outline the five-step incisionless procedure.

Outcomes and experience to date

Since the procedure's introduction, Drs. Brault and Shin note that minor revisions in its protocol have helped reduce incomplete transection rates. Patients typically recover in about two weeks instead of the 4 to 6 weeks needed after open surgery.

Although published clinical outcome data associated with TCTR are limited at this time, the published data discussed by the co-authors suggest that patients treated with TCTR had symptom severity scores, function scores and satisfaction rates exceeding those associated with OCTR and ECTR in comparable studies, with no adverse events.

"Ultrasound-assisted, minimally invasive procedures such as the thread carpal tunnel release have the potential to revolutionize how we treat some common conditions," explains Dr. Brault. "Thread carpal tunnel release is an eloquent and straightforward technique that offers patients quicker pain relief and recovery than conventional open carpal tunnel releases."