History
Acute carpal tunnel syndrome (CTS) can develop after a major trauma to the upper extremity (typically a distal radius fracture), a carpal dislocation, or a crush injury. Swelling, pain, and paresthesia in the median nerve distribution of the hand (palmar and radial) are observed.
In the more common idiopathic or chronic CTS, symptoms are more gradual in onset. [23] Pain and paresthesia in the median nerve distribution of the hand are common. Symptoms are often worse at night and can wake a patient from sleep. As the condition worsens, daytime paresthesia becomes common and is often aggravated by daily activities, such as driving, combing the hair, and holding a book or phone. Weakness can be present. With long-standing or severe cases of CTS, thenar atrophy is frequently observed.
Because of the motor and sensory disturbances, manual dexterity is diminished, and difficulty with such daily activities as buttoning clothes and holding small objects is often encountered. Pain and paresthesia can also occur proximally in the forearm, elbow, shoulder, and neck in as many as one third of patients. Pain and paresthesia in the hand are not always isolated to median nerve distribution but can involve the ulnar aspect or the entire hand.
Physical Examination
A thorough physical examination of the neck and upper extremity should be performed. Clinical tests to evaluate for CTS include sensory evaluations and provocative maneuvers that attempt to elicit signs or symptoms of median nerve compression at the wrist.
Sensory evaluations used in the workup include the following:
-
Semmes-Weinstein pressure monofilaments - Monofilaments of increasing diameter are pressed perpendicularly against the palmar aspect of each finger until the monofilament bends to determine the sensory threshold for each finger; values greater than 2.83 may be indicative of CTS
-
Vibratory sensibility - A 256-Hz tuning fork is struck against an object, causing it to vibrate, and the fork's prong is then placed against the patient's fingertips; the median and ulnar fingers of both hands are tested, and the test is considered positive if decreased sensation is perceived
-
Static and moving two-point discrimination - This is the minimum separation between two points (either static or moving) that can be perceived; failure to discriminate more than 6 mm (static) or 5 mm (moving) is a positive finding
Threshold tests (Semmes-Weinstein pressure monofilaments and vibratory sensibility) reflect gradual decreases in nerve function, but the innervation density tests (two-point discrimination) can remain normal until nearly all sensory conduction has ceased
Provocative tests include the following [24] :
-
Phalen wrist flexion test - The patient's elbows are placed on a table, with the forearms perpendicular to the table and the wrists flexed, and this position is held for 60 seconds; the test result is positive if numbness or paresthesia develops in radial-side digits
-
Tinel test - The examiner taps along the course of the median nerve on the volar aspect of the wrist; the test result is positive if paresthesia is elicited in the median nerve distribution
-
Carpal compression test - Direct application of pressure of 150 mm Hg or even pressure from both thumbs of the examiner is exerted on the patient's carpal canal and maintained for 30 seconds; the test result is positive if pain, numbness, or paresthesia develops in the radial-side digits
-
Cross sections of carpal canal at levels of proximal and distal carpal rows. Transverse carpal ligament bridges carpal tunnel and is under tension.
-
Surgical incision for open carpal tunnel release. Incision can be extended proximally across wrist flexion crease for more extended exposure.
-
Surgical incisions for endoscopic carpal tunnel release (one- and two-incision techniques). Precise location of incisions is critical and depends on individual anatomy.
-
Carpal tunnel release (part 1). Skin incision and retraction. Procedure performed by Deepak Kapila, MD, Broward Health, Fort Lauderdale, FL. Courtesy of BroadcastMed (http://ortho.broadcastmed.com/4229/videos/carpal-tunnel-surgery).
-
Carpal tunnel release (part 2). Exposure of palmar aponeurosis and transverse carpal ligament; entry into carpal tunnel. Procedure performed by Deepak Kapila, MD, Broward Health, Fort Lauderdale, FL. Courtesy of BroadcastMed (http://ortho.broadcastmed.com/4229/videos/carpal-tunnel-surgery).
-
Carpal tunnel release (part 3). Division of transverse carpal ligament, removal of tenosynovium, and release of median nerve. Procedure performed by Deepak Kapila, MD, Broward Health, Fort Lauderdale, FL. Courtesy of BroadcastMed (http://ortho.broadcastmed.com/4229/videos/carpal-tunnel-surgery).
-
Carpal tunnel release (part 4). Completion. Procedure performed by Deepak Kapila, MD, Broward Health, Fort Lauderdale, FL. Courtesy of BroadcastMed (http://ortho.broadcastmed.com/4229/videos/carpal-tunnel-surgery).
-
Minimally invasive endoscopic carpal tunnel release. Procedure performed by Marc Tanner, MD, Bon Secours Health System, Greenville, SC. Courtesy of BroadcastMed (http://ortho.broadcastmed.com/4120/videos/minimally-invasive-endoscopic-carpal-tunnel-release).
