What is the recommended medical management for carpal tunnel syndrome, including conservative measures, pharmacotherapy, steroid injection, and criteria for surgical referral?

Medical Management of Carpal Tunnel Syndrome

For patients with mild to moderate carpal tunnel syndrome, begin with nighttime wrist splinting in neutral position for 3-9 weeks, followed by corticosteroid injection into the carpal tunnel if splinting fails, reserving surgery for those who do not respond to conservative measures after 4-6 months. 1

Initial Conservative Management (First-Line Treatment)

Wrist Splinting

• Nighttime wrist splinting in neutral position should be worn continuously for 3-9 weeks as the primary conservative intervention 1, 2, 3
• Dorsal lock wrist-hand orthosis may provide superior pain relief compared to traditional volar cock-up splints by maintaining the wrist in neutral position more effectively 3
• Splinting is most effective in patients with symptom duration less than 3 months and absence of sensory impairment at presentation 2

Activity Modification

• Patients should reduce repetitive gripping and forceful hand activities that exacerbate median nerve compression 1, 4
• Avoid prolonged wrist flexion or extension positions during work and daily activities 1

Pharmacotherapy Limitations

• Discontinue ineffective over-the-counter analgesics such as acetaminophen and ibuprofen, as NSAIDs have limited efficacy for nerve compression 1
• Oral NSAIDs and acetaminophen do not address the underlying median nerve compression and should not be relied upon as adequate conservative treatment 1

Second-Line Treatment: Corticosteroid Injection

Indications for Injection

• Proceed to corticosteroid injection when wrist splinting has failed to provide adequate relief after 3-9 weeks 1, 2, 5
• Injection is appropriate for patients with moderate symptoms who have not responded to first-line conservative measures 1, 5

Injection Protocol and Efficacy

• Inject 40-80 mg methylprednisolone directly into the carpal tunnel 5, 6
• Corticosteroid injection provides significant symptom improvement lasting up to 6 months (SMD -0.58,95% CI -0.89 to -0.28) 5
• Functional improvement is evident at up to 3 months (SMD -0.62,95% CI -0.87 to -0.38) 5
• The requirement for surgery is reduced at one year (risk ratio 0.84,95% CI 0.72 to 0.98) 5
• Up to three injections may be administered, though most benefit occurs with the first injection 2

Expected Response Rates

• Only 10% of patients will have lasting symptom relief beyond one year with injection and splinting alone 2
• Patients with symptom duration less than 3 months and no sensory impairment have the best response to conservative treatment 2
• Nerve conduction parameters improve significantly at 1 month and remain improved at 6 months in responders 7

Adverse Events

• Adverse events are uncommon and generally mild 5
• Approximately 65% of patients experience mild-to-moderate pain lasting less than 2 weeks after injection 5
• Severe complications occur in less than 1% of cases (severe pain resolving over several weeks, or transient sympathetic reaction) 5

Critical Pitfalls to Avoid

Timing of Injection Before Surgery

• Do not inject corticosteroids within 3 months of planned surgery, as this increases infection risk 1
• If conservative treatment fails, schedule surgery without additional injections in the preceding 3-month period 1

Inappropriate Patient Selection

• Do not proceed directly to surgery in patients with very mild electrodiagnostic findings without attempting conservative treatment, as 48-63% will respond to conservative measures 1
• Exclude patients with thenar muscle wasting or obvious underlying medical causes (diabetes, hypothyroidism, rheumatoid arthritis) from conservative management, as they require more aggressive treatment 2

Inadequate Conservative Trial

• Do not consider conservative management to have "failed" unless the patient has completed at least 4-6 months of appropriate treatment 1
• A single failed intervention (splinting alone or injection alone) does not constitute adequate conservative management 1, 2

Criteria for Surgical Referral

Indications for Surgery

• Surgical decompression (open or endoscopic carpal tunnel release) should be offered to patients with moderate-to-severe CTS who have failed 4-6 months of conservative management 1
• Immediate surgical referral is appropriate for patients with severe sensory loss or thenar muscle atrophy at presentation 1, 2
• Surgery provides superior symptom relief compared with all non-surgical options and is the most effective treatment for moderate-to-severe cases 1

Prognostic Factors for Surgical Success

• Patients younger than 40 years show significantly higher improvements in postoperative scores (p < 0.001) 1
• Shorter symptom duration (less than 1 year) is associated with better surgical outcomes 1
• Preoperative neurological status serves as a clinical predictor of surgical success 1

Diagnostic Considerations

Role of Electrodiagnostic Studies

• Obtain electrodiagnostic testing when clinical examination is positive and surgical management is being considered, to determine severity and surgical prognosis 1
• Electrophysiologic studies are not routinely required for diagnosis in typical cases but help guide treatment decisions 1

Imaging

• Ultrasound may measure median nerve cross-sectional area and is highly sensitive and specific for diagnosis, though not routinely necessary 1
• MRI without contrast may be appropriate in selected circumstances when diagnosis is unclear 1