Carpal tunnel syndrome is technically classified as an entrapment neuropathy. This means that the nerve is damaged at sites where it passes through narrow or restricted spaces. Carpal tunnel syndrome is the most common entrapment neuropathy and results from compression of the median nerve when it travels through the ‘carpal tunnel’ in the wrist. The carpal tunnel consists of bones, ligaments, tendons and of course the median nerve. All these structures make it quite squishy for the median nerve to travel. This can result in people experiencing pain, tingling, numbness, and even weakness in the hand.
Causes
Like many conditions we are unsure about specific causes for carpal tunnel syndrome. What we do have is suspected risk factors associated with hormonal changes, mechanical stimuli, and structural changes. Some of these suspected risk factors include diabetes, menopause, hypothyroidism, obesity, arthritis, pregnancy, excessive computer use, and smoking. These risk factors need to be considered during the assessment and management of carpal tunnel syndrome.
Clinical Features
Because there is no known cause for carpal tunnel syndrome how an individual presents to a clinic becomes an important tool in diagnosis. Carpal tunnel generally begins as intermittent tingling and numbness, particularly at night. As it progresses these symptoms tend to increase in frequency and severity and become noticeable during day time activities. Part of the progression of carpal tunnel syndrome is numbness, weakness, and wasting of the muscles on the thumb side of your hand. In severe cases pain can spread into the forearm and up the arm. Symptoms of carpal tunnel syndrome generally affect the first 3 fingers, as this is where the median nerve travels.
Diagnosis
Carpal tunnel syndrome is largely diagnosed by how the individual presents and their clinical features. There are some clinical tests that can be used that look at nerve sensitivity, and muscle strength. However, these tests are often combined with the clinical features present to give a clearer picture of what is going on. This makes it important for individuals to obtain an expert assessment to determine what exactly is happening. Further testing can be conducted, and these include sensory and motor nerve conduction studies of the median nerve. These tests aim to determine how the median nerve is functioning. Other conditions that may present similar to carpal tunnel syndrome include cervical radiculopathy and osteoarthritis in the wrist.
Management
Education and Activity Modification
First line treatment for carpal tunnel syndrome should be education of individuals in regards to activity modification. This can be done by implementing an ergonomically friendly workspace and limiting activities involving repeated wrist movement and heavy lifting. The aim is to reduce the stress being placed on the median nerve and subsequently reduce the symptoms.
Musculoskeletal Manipulation
This includes manual therapy techniques such as soft tissue therapy of the forearm and hand muscles, and mobilisation of the wrist joint. It also includes exercises targeted at muscle flexibility and neural mobility. The aim of these techniques is to reduce the stress being placed on the median nerve by the surrounding structures in the carpal tunnel. Splinting, particularly night splints, can also be used for a similar effect.
Corticosteroid Injection
Corticosteroid injections done under ultrasound are commonly used in the management of carpal tunnel syndrome. The aim of the injections is to reduce swelling. By doing this more space is created between the median nerve and muscle tendons which reduces the compressive stress placed on the nerve.
Surgery
The main surgical procedure for carpal tunnel syndrome is a carpal tunnel release or decompressive surgery. Again, the aim is to create as much space for the median nerve to travel through the carpal tunnel to reduce the stress placed upon it. Both surgical and non-surgical options have been shown to be effective in the management of carpal tunnel syndrome. Surgery tends to have better long-term outcomes in the resolution of symptoms associated with carpal tunnel syndrome. However, there are greater risks and complications associated with surgery which need to be discussed and considered before jumping in.