23.1 Description

Carpal tunnel syndrome (CTS) is the most common compressive neuropathy affecting the general population, which is characterized by numbness, paresthesias, and pain in the distribution of the median nerve. A thorough history and complete physical examination are necessary to rule out other pathologies such as cervical spine issues, motor neuron problems, or polyneuropathy. Evidence has shown that while non-operative modalities of splinting and corticosteroid injection are effective, surgical release has a superior outcome at 3 and 18 months compared to conservative modalities. ¹ Carpal tunnel release is performed over 400,000 times a year in the United States. ²

23.2 Key Principles

CTS is primarily a clinical diagnosis, based on symptom characteristics and physical findings. The degree of compression of the median nerve should be discussed with the patient preoperatively, as chronic compression can damage the nerve permanently, limiting the clinical impact of surgery. When carpal tunnel release is undertaken, complete release of the transverse carpal ligament is the most critical step of the procedure.

23.3 Expectations

The outcomes of carpal tunnel surgery vary depending on the severity of nerve compression. It is important to explain to patients that the most reliable outcome from release of the transverse carpal ligament is prevention of disease progression. Patients generally experience resolution of their nocturnal neuropathic pain almost immediately, followed by improvement in paresthesias over the course of months. Patients afflicted with severe compression of the median nerve, resulting in weakness and thenar atrophy, should be warned that they may have minimal relief of numbness after carpal tunnel release, although neuropathic pain is predictably resolved after surgery.

23.4 Indications

Carpal tunnel release is recommended for patients who have failed conservative management including splints, analgesics, or corticosteroid injections. Surgery is also recommended in patients who present with evidence of thenar atrophy. In a patient with recurrent CTS, open revision release is recommended to ensure direct visualization and complete release of the transverse carpal ligament. If acute CTS develops in association with other pathologies (e.g., distal radius fracture, perilunate dislocation, or compartment syndrome), open carpal tunnel release is recommended for visualization of hematoma and other nerve compressive pathology.

23.5 Contraindications

CTS is primarily a clinical diagnosis, although electromyography and nerve conduction can provide adjunctive support. In a patient with equivocal symptoms or a confusing clinical picture, diagnostic steroid injection is recommended. If steroid injection does not temporarily resolve symptoms, carpal tunnel release is unlikely to address the problem ³ and is relatively contraindicated. In addition, surgical intervention is generally not required in women who develop CTS during pregnancy. The majority of pregnant patients with CTS experience symptom resolution after parturition.

23.6 Instructions, Positioning, and Anesthesia

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  Patient should be positioned supine on the operating table with the operative arm on a hand table.

  
  
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  The procedure is performed under tourniquet control with choice of regional anesthesia, Bier block, or local anesthesia.

  
  
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  Another option is the recently described technique of wideawake local anesthesia with no tourniquet (WALANT). ⁴

  
  
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  Lidocaine with epinephrine is used to decrease local site bleeding and obviates need for a tourniquet.

  
  
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  Use of WALANT is particularly beneficial to patients with medical comorbidities who have risks associated with sedation or regional anesthetics.