This month’s newsletter has been written by Dr Roger Cooke. In addition to being a central member of the Occupational Health Consultancy’s clinical team, Dr Cooke is a consultant and senior lecturer in Occupational Medicine with a particular interest in hand arm vibration and musculoskeletal problems including carpal tunnel syndrome. He has published a number of articles in professional journals and was a contributing author to the latest edition of the standard textbook “Fitness for Work”, and a recent textbook on clinical assessment.
Carpal tunnel syndrome (CTS) is a common condition in which one of the nerves at the wrist (the median nerve) is unable to function properly, usually because of increased pressure in the tunnel through which it passes – hence the name of the syndrome.
There are many causes of CTS. It is particularly common in females, often being associated with fluid retention, but may be due to a number of other medical conditions, including arthritis and obesity. It usually starts with tingling or numbness affecting the thumb, index and middle fingers, or sometimes in the whole hand. This may occur at any time but typically wake the sufferer during the night. It can cause weakness of the thumb, sensitivity of the hand to cold and changes in the colour and sweatiness of the hand. Pain may be a feature which
causes distress. Working ability may be affected by the pain, or by the loss of sensitivity of the affected fingers, causing difficulty with some tasks, especially those requiring fine manipulative dexterity.
Because it is common, most companies will, at some stage, have an employee with the condition, and sometimes there will be concern that work has either caused it or contributed to it.
A number of work factors are recognised as increasing the risk of and individual developing CTS. This includes high frequency high force repetitive work, and work while gripping with the wrist bent. Use of hand held vibratory tools may also contribute to CTS.
Where the workplace issues are felt to be contributory – either vibration or recent repetitive work (which is tightly defined by the Department of Work and Pensions for this purpose) – the individual may be eligible for receipt of industrial injuries benefit. Employees may also make common law claims for CTS. If CTS is diagnosed by a doctor and has developed in association with exposure to hand transmitted vibration, it is reportable under the Reporting of Injuries Diseases and Dangerous Occurrences Regulations (RIDDOR).
Employers can and should reduce the risk of workplace factors being implicated in the development of CTS by ensuring that adequate risk assessments have been done in accordance with the Manual Handling Regulations, Control of Vibration at Work Regulations and Display Screen Equipment Regulations.
Those risk assessments will identify tasks that have a high risk of CTS so that adjustments can be considered to reduce that risk. Examples of work issues that could cause problems include repetitive assembly work, food processing, exposure to hand transmitted vibration or poor keyboard ergonomics.
Once the condition has become symptomatic, early treatment is essential. Nerve conduction studies may be required to confirm the diagnosis, but treatment can be started before the results are available. In the early stages, use of an appropriate wrist splint, non steroidal anti-inflammatory drugs and physiotherapy may help. More severe cases may require a steroid injection to the wrist, or operation to relieve the pressure. Although there will be some variation depending on the individual, and the nature of their job, an absence from work of around three months is typical after such surgery.
Occupational health advice can include helping with the risk assessments, seeing employees with symptoms and helping arrange treatment, as well as advising whether or not work is likely to have contributed to an individual case.