Carpal tunnel syndrome is the most common compression neuropathy affecting the upper limb, which results from the entrapment of the median nerve in the carpal tunnel. Carpal tunnel syndrome adversely affects daily activities, limits work capacity, and impacts general health and quality of life. In a primary care population, prevalence has been reported to be 3720 to 5700 per 100,000 people in a year, with an annual incidence of 72 to 8200 per 100,000. CTS is more common in women with a female-to-male ratio ranging between 0.78 and 9.66.
Carpal Tunnel Syndrome is a common condition characterized by median nerve compression at the wrist. Understanding the causes and pathophysiology of CTS is crucial for effective treatment. While non-surgical interventions, such as medications, splinting, and physical therapy, are often the initial approach, corticosteroid injections and surgery may be necessary in more severe cases. It is important to consult with a healthcare professional to determine the most suitable treatment plan based on individual circumstances. With proper management, individuals with carpal tunnel syndrome can experience significant relief and improved hand function.
Carpal Tunnel Syndrome can be caused by several factors, including:
Certainly! Here’s a paragraph explaining the pathophysiology of carpal tunnel syndrome:
The pathophysiology of carpal tunnel syndrome (CTS) revolves around the compression and irritation of the median nerve as it passes through the carpal tunnel. The carpal tunnel is a narrow passageway in the wrist formed by the carpal bones and a transverse ligament. When the tissues within the carpal tunnel become inflamed or swollen, the available space for the median nerve decreases, leading to compression.
The primary contributors to this compression are the flexor tendons that pass through the tunnel and the synovial sheaths surrounding them. With repetitive hand and wrist movements or sustained wrist positions, these tendons can become irritated and inflamed, causing them to thicken and encroach upon the already limited space within the tunnel. This leads to increased pressure on the median nerve, which results in the characteristic symptoms of CTS, including pain, numbness, tingling, and weakness in the hand and fingers.
Over time, if left untreated, the prolonged compression of the nerve can cause damage and loss of nerve function.
The diagnosis is based on clinical history, examination findings, and provocation tests.
Two common provocation tests used for the diagnosis of carpal tunnel syndrome are Phalen’s sign, with a sensitivity of 10 to 73% and specificity of 55–86%, and Tinel’s sign with 8–100% page sensitivity and 55–87% specificity.
Nerve conduction tests are commonly used to diagnose and evaluate the severity of carpal tunnel syndrome. During this test, small electrodes are placed on specific points along the hand and wrist. A mild electrical impulse is then applied to the median nerve, and the speed and strength of the nerve signals are measured. This test helps determine if there is a delay or blockage in the conduction of nerve signals through the carpal tunnel. It can provide valuable information about the extent of nerve compression and assist in confirming the diagnosis of carpal tunnel syndrome. Nerve conduction tests are especially useful when the clinical presentation is atypical or when surgical intervention is being considered. They can help guide treatment decisions and provide baseline measurements for comparison during follow-up assessments.
Corticosteroid injection is a well-studied and effective intervention for patients with mild and moderate CTS. It is a straightforward procedure with minimum side effects that can result in remarkable improvement of symptoms and functional status even within the first week after injection. The Ultrasound guidance might improve the accuracy and the effectiveness of steroid injection in CTS.
In The Lancet, Linda S Chesterton and colleagues report the results of a randomised trial done in 25 UK primary care centres, which compared a single steroid injection (20 mg methylprednisolone acetate) with 6 weeks’ night splinting in patients with mild or moderate carpal tunnel syndrome. Among the 212 patients who completed the questionnaire, the overall Boston Carpal Tunnel Questionnaire score (combined symptom severity and functional status scores, 1–5 scale) at 6 weeks was significantly better in the injection group than in the night splint group by an adjusted mean difference of −0·32 (95% CI −0·48 to −0·16), corresponding to an effect size of 0·41. At 6 weeks, the mean symptom severity score improvement was 0·84 in the injection and 0·48 in the splint group. Between-group differences did not persist at 6 months. It is important to highlight the participants’ characteristics: 199 (85%) had a first-time carpal tunnel syndrome diagnosis and all had symptoms for at least 6 weeks.
Many approaches to carpal tunnel injection have been studied by several authors. Formerly, one of the most widely used techniques was the midline longitudinal US-guided injection. This method had some disadvantages; especially, when we aim to perform perineural injection, sometimes called hydro-dissection. Previous research advocated that a short-axis or transverse scan is superior to a long-axis scan considering that the US image in a longitudinal scan might confuse operators between swollen nerve fascicles, muscles, and inflamed tendons in the same plane; hence, raising concerns regarding the incidence of nerve trauma due to injections in the long-axis (longitudinal) scan.
Smith et al developed the in-plane ulnar approach for the administration of US-guided carpal tunnel injection. Several studies showed that US-guided local steroid injection using an in-plane ulnar approach in the CTS might be more effective than out-of-plane injections. Nonetheless, other injection approaches had not been evaluated in the prior studies. The primary purpose of this study was to compare the efficacy and safety of the in-plane radial versus the more common ulnar in-plane approach in US-guided carpal tunnel injection.
Surgical treatment for carpal tunnel syndrome should be considered for individuals who have moderate to severe symptoms that significantly impact their daily activities and have not responded well to conservative treatments such as splinting, medications, injections and physical therapy.
Surgical intervention, known as carpal tunnel release (CTR), may be recommended to relieve the compression of the median nerve in the wrist.