Carpal Tunnel Syndrome

Patients describe intermittent numbness, tingling, and burning pain in the thumb, index, middle, and radial half of the ring finger. Symptoms are classically nocturnal, waking the patient who shakes the hand for relief (the flick sign). Daytime triggers include driving, reading, and holding a phone. Pain may radiate proximally up the forearm. With progression, sensory symptoms become constant, fine motor tasks (buttoning, picking up coins) deteriorate, and thenar wasting appears.

Examination:

• •Inspect for thenar wasting and trophic changes
• •Test sensation in the median distribution, sparing the thenar eminence (supplied by the palmar cutaneous branch, which passes superficial to the flexor retinaculum)
• •Test APB power (resisted thumb abduction perpendicular to the palm)
• •Provocation tests: Tinel's sign (percuss over the median nerve at the wrist), Phalen's test (1 minute of sustained wrist flexion), and the carpal compression test (Durkan's, direct pressure for 30 seconds). The carpal compression test is the most sensitive and specific

Differentiate from cervical radiculopathy (C6-C7), proximal median neuropathy (pronator syndrome, which involves the palmar cutaneous branch and FPL/FDP-index weakness), and thoracic outlet syndrome.

CTS is a clinical diagnosis. NICE CKS supports a treatment trial without electrodiagnostic confirmation in classical presentations with positive provocation tests.

Nerve conduction studies (NCS) and electromyography are indicated when:

• •Diagnosis is uncertain (atypical symptoms, normal provocation)
• •Surgery is being planned (objective severity grading aids prognosis)
• •An alternative or co-existing neuropathy is suspected (cervical radiculopathy, generalised polyneuropathy)
• •Symptoms are bilateral with possible systemic cause

NCS findings: prolonged distal sensory latency is the earliest abnormality, followed by reduced sensory amplitude, prolonged distal motor latency, and reduced thenar motor amplitude in severe cases. Comparison with the ulnar nerve at the same wrist helps when distal latencies are borderline.

Ultrasound shows an increased median nerve cross-sectional area at the carpal tunnel inlet (typically >10-12 mm squared) and is useful in identifying space-occupying lesions, anatomical variants, or active synovitis. MRI is reserved for suspected secondary causes (tumour, ganglion, persistent median artery). Routine bloods (HbA1c, TFTs) are considered when systemic risk factors are suspected.

Management is graded by symptom severity and electrodiagnostic findings (NICE CKS, BSSH guidance).

Mild to moderate disease (intermittent symptoms, no motor loss): conservative trial for 6-8 weeks.

• •Night-time wrist splinting in neutral position (most effective single intervention)
• •Activity modification and ergonomic advice
• •Simple analgesia; NSAIDs offer limited benefit
• •Manage underlying contributors (glycaemic control, weight, thyroid)

Failed conservative measures or moderate symptoms: corticosteroid injection (typically methylprednisolone 40 mg with 1% lidocaine), delivered ulnar to the palmaris longus or via ultrasound guidance. Provides symptom relief in approximately 80% at 6 weeks but ~50% relapse by 12 months. NICE supports up to two injections before surgical referral.

Severe disease, persistent symptoms, motor deficit, or thenar wasting: surgical decompression (carpal tunnel release). Open release and endoscopic release have equivalent long-term outcomes (NICE TA8 historic reference; Cochrane Vasiliadis 2014). Endoscopic offers faster early recovery; open is technically simpler and the UK default. Performed under local anaesthetic as a day case.

Referral pathway: refer for surgical opinion if there is thenar wasting, persistent constant numbness, severe NCS findings, or failure of two injections.

Conservative pathway: night splinting is continued during the conservative trial. Nerve and tendon gliding exercises may be added under hand therapy supervision; evidence is modest but the risk is low. Ergonomic adjustment of keyboard, mouse, and tool use addresses provocation.

Post-operative (carpal tunnel release):

• •Week 0-1: bulky dressing for 48 hours, then a light dressing. Encourage immediate finger movement, elevation, and oedema management. Avoid heavy gripping
• •Week 2: sutures removed (open release). Scar massage begins
• •Week 2-6: progressive return to light activity. Pillar pain (tenderness over the thenar and hypothenar eminences) is common and usually settles by 3 months
• •Week 6-12: return to manual work and sport. Strength typically returns to 80% of contralateral by 12 weeks

Sensory recovery is rapid in early disease; in severe pre-operative CTS, sensation may improve over 12-18 months and thenar bulk may not fully recover. Counsel patients accordingly. Persistent or recurrent symptoms beyond 6 months warrant re-assessment for incomplete release, missed pathology, or recurrent compression.

• •NICE CKS Carpal Tunnel Syndrome - Supports clinical diagnosis, conservative-first management, and up to two steroid injections before surgical referral. NCS not mandatory for classical presentations.
• •BSSH Carpal Tunnel Patient Information - UK hand-surgery framework: open release remains the default; endoscopic offers earlier return to function with equivalent long-term outcomes.
• •Cochrane (Vasiliadis 2014) - Endoscopic and open carpal tunnel release produce equivalent symptom relief at 12 months; endoscopic offers faster early recovery.
• •Padua classification (1997) - Six-tier neurophysiological severity grading still used to stratify pre-operative disease and predict outcomes after release.
• •Atroshi et al. NEJM (2006) - Surgical decompression produced superior symptom relief at 12 months versus splinting in moderate to severe CTS, supporting earlier surgical referral when conservative measures fail.

• •Palmar cutaneous branch leaves the median nerve proximal to the flexor retinaculum and runs superficial to it, so thenar sensation is spared in CTS. Loss of thenar sensation points to a proximal median lesion (pronator syndrome).
• •Carpal compression test (Durkan's) is more sensitive and specific than Tinel's or Phalen's. Vignette stems that emphasise sustained compression provoking symptoms point to CTS.
• •NCS are not required to diagnose classical CTS. They are required when surgery is planned, the picture is atypical, or another neuropathy is suspected.
• •Pregnancy-associated CTS is usually self-limiting and resolves within months of delivery. Splinting is first-line; avoid steroid injection unless symptoms are severe.
• •Thenar wasting and fixed sensory loss are red flags for axonal loss. Refer for surgical decompression rather than further conservative trials; pre-operative severity predicts recovery.
• •Differentiate from C6 radiculopathy (neck pain, reflex change, dermatomal not nerve-territory sensory loss) and pronator syndrome (forearm pain, palmar cutaneous involvement, weak FPL and FDP-index).