Onset and Duration of Forearm Nerve Blockade

Onset and Duration of Forearm Nerve Blockade Performed With a Single Distal Injection Versus Sequential Injections at Distal and Proximal Locations Alongside the Nerves: A Blinded Randomized

This pilot study will evaluate the latency of onset and duration of sensory-motor block in patients undergoing hand surgery. Patients will be randomized to receive nerve blocks of the distal forearm or of the distal and proximal forearm. Local anesthetic will be injected to anesthetise the median and ulnar nerves in the distal forearm (1-injection site group) or the median and ulnar nerves in the distal and proximal forearm (2-sequential injection sites group) to accomplish anesthesia for surgery on the hand.

Inclusion Criteria:

• Scheduled to undergo daycare surgery for carpal tunnel syndrome under peripheral nerve blocks
• American Society of Anesthesiologists (ASA) physical status I, II or III
• Able to demonstrate sensory function in the ulnar and median nerve distribution by exhibiting sensitivity to cold, pinprick and light touch
• Scheduled to undergo primary hand surgery
• Able to understand the Dutch language, purpose and risks of the study
• Able to provide informed consent and authorization to use protected health information, adhere to the study visit schedule, and complete all study assessments

Exclusion Criteria:

• Currently pregnant or nursing
• History of hypersensitivity to local anesthetics
• Contraindication to lidocaine, bupivacaine, paracetamol
• Medical condition that will make it difficult to assess sensory distributions of the upper extremity peripheral nerves or to communicate with staff
• Suspected or known recent history (< 3 months) of drug or alcohol abuse
• Concurrent physical condition that may require analgesic treatment (such as NSAID or opioid) in the postsurgical period for pain that is not strictly related to Carpal Tunnel Syndrome and which may confound the postsurgical assessments
• Infection at the planned block site(s)
• Initiation of treatment with any of the following medications within 1 month of study drug administration or if the medication(s) are being given to control pain: selective serotonin reuptake inhibitors (SSRIs), selective norepinephrine reuptake inhibitors (SNRIs), gabapentin, pregabalin (Lyrica®), or duloxetine (Cymbalta®)
• Body weight <40 kg or body mass index >44 kg/m2
• Uncontrolled anxiety, psychiatric, or neurological disorder that might interfere with study assessments
• Any chronic neuromuscular deficit affecting the Ulnar and Median nerves or muscles of the surgical extremity
• Any chronic condition or disease that would compromise neurological
• Presence of pre-existing coagulation disorders
• Baseline neurological deficits