What's going on
The carpal tunnel is a narrow tunnel formed by the carpal bones and the tough transverse ligament. The digital flexor tendons and the median nerve pass through it. Any decrease in the volume of the canal or swelling of its contents leads to compression of the nerve: first sensitivity is impaired, then motor function suffers.
This makes it clear why the symptoms intensify at night: during sleep, the hand remains in a bent position for a long time, and the fluid is redistributed, increasing the pressure in the canal.
Symptoms and their dynamics
- Ранняя стадия: ночное онемение и покалывание в большом, указательном, среднем и половине безымянного пальца. Человек просыпается, встряхивает кисть или опускает руку вниз — и становится легче.
- Развёрнутая стадия: онемение появляется и днём — при работе за компьютером, вождении, удержании телефона; присоединяется жгучая боль, отдающая в предплечье.
- Поздняя стадия: постоянное онемение, слабость захвата, атрофия мышц возвышения большого пальца, невозможность выполнять точные движения.
Who's at risk
- Prolonged monotonous work with a hand: working at a computer with an incorrect hand position, assembly operations, working with vibrating tools
- Diabetes mellitus and hypothyroidism
- Pregnancy - due to fluid retention; usually goes away after childbirth
- Rheumatoid arthritis and other inflammatory joint diseases
- Obesity
- Consequences of a fracture or dislocation in the wrist
Diagnostics
- Осмотр невролога с проверкой чувствительности, силы кисти и специальных проб (тесты Тинеля и Фалена).
- Электронейромиография — main метод: показывает степень нарушения проведения по срединному нерву и объективно оценивает тяжесть.
- УЗИ срединного нерва — выявляет утолщение нерва и причины сдавления (кисты, тендовагинит).
- Обследование щитовидной железы и уровня глюкозы при двустороннем поражении.
- При подозрении на шейную причину — визуализация шейного отдела позвоночника.
Treatment
In the early stages, in most cases it is possible to do without surgery. The basis of conservative treatment is unloading the canal and eliminating provoking factors.
- An orthosis (splint) on the wrist in a neutral position, primarily at night - the method with the best evidence among conservative ones
- Changes in ergonomics: position of the keyboard and mouse, breaks, avoidance of prolonged wrist flexion
- Short course anti-inflammatory drugs for pain
- Injection of a glucocorticosteroid into the canal area provides a pronounced, although often temporary, improvement
- Physiotherapy: magnetic therapy, ultrasound therapy as auxiliary methods
- Treatment of the underlying disease: compensation for diabetes, correction of hypothyroidism
Surgical treatment - dissection of the transverse carpal ligament - is indicated in the absence of effect from conservative therapy, pronounced changes in ENMG and especially when muscle atrophy appears. You should not delay surgery for atrophy: muscle restoration is not always possible.
Prevention
- Keep your wrist straight when working at the computer, use a wrist rest
- Take breaks every 45–60 minutes to warm up your wrists
- Do not sleep with your wrists bent too much; if inclined, wear the orthosis at night
- Monitor blood sugar and thyroid function
- When working with vibrating tools, use anti-vibration gloves
