Used to provide local anesthesia to the digits for repair, reduction, or drainage

    Lacerations

    Nail bed injuries

    Infections (i.e., felons, paronychias)

    Amputations

    Fractures or dislocations

CONTRAINDICATIONS

 Absolute Contraindications

    Transthecal technique contraindicated in cases of infection, including felon, tenosynovitis, and overlying cellulitis

    Allergy to lidocaine, bupivacaine, or other selected anesthetic

 Relative Contraindications

    Complex laceration or other injury involving multiple digits that can be more easily and adequately anesthetized with a nerve block at the wrist

RISKS/CONSENT ISSUES

 Pain (site of needle insertion)

 Bleeding (local at needle puncture site)

 Infection (theoretical risk of iatrogenic infection)

 Potential for damage to neurovascular bundle

 Paresthesias

 Possible need for additional anesthetic or alternate procedures if the initial nerve block fails

LANDMARKS

 The common digital nerves divide into two pairs of nerves corresponding to the dorsal and volar sides of the digits

 Palmar Nerve

    Located at the 4- and 8 o’clock positions when looking at a cross section of the digit

    Supplies the volar surface of the digit and the dorsal surface distal to the distal interphalangeal (DIP) joint for the middle three fingers

    Blocking only the palmar nerves will provide adequate anesthesia on fingertip injuries distal to the DIP for the three middle fingers

 Digital Nerve

    Located at the dorsal 2- and 10 o’clock positions when looking at a cross section of the digit

    Supplies the nail beds of the thumb, fifth digit, and dorsal aspects of all three middle fingers up to the DIP

 For the thumb and fifth digit, all four nerves must be blocked for fingertip and nail bed anesthesia (FIGURE 52.1)

TECHNIQUE: SEVEN APPROACHES

 Patient Preparation

    Document neurovascular examination before anesthesia

    Place patient’s affected hand/foot comfortably on bedside procedure table with volar surface down (for metacarpal nerve block, traditional ring block, wing block) or volar surface up (for subcutaneous block, transthecal approach or thumb block)

    Prepare the digit and web space by using standard aseptic technique

 Equipment

    Lidocaine or procaine 1% to 2% (or 0.25% bupivacaine for longer, complicated procedures), 2 to 3 mL

    An 18-gauge needle for drawing up the anesthetic

    A 25- to 30-gauge needle for the nerve block

    A 5-mL syringe

    Povidone–iodine or chlorhexidine solution

    Sterile drapes and sterile gauze

    Gloves

 Traditional Digital Block (Web-space Block or Metacarpal Nerve Block)

    Anesthetizes all digits except great toe

    Prepare skin over dorsal surface of web space between metacarpal/metatarsal heads

    Aspirate and inject subcutaneous wheal between metacarpal/metatarsal bones on dorsum of hand/foot 1 to 2 cm proximal to web space

    Slowly advance needle through the wheal toward lateral volar surface of metacarpal/metatarsal head until slight tenting of the volar surface is appreciated

    Aspirate and then inject 2 mL of anesthetic

    Repeat the process on the opposite side of the finger/toe

 Traditional Three-sided Ring Block

    Anesthetizes all digits including the dorsal, medial, and lateral nerve branches of great toe

    Give two injections of lidocaine, one on each side of the digit

    Locate dorsal–lateral aspect of proximal phalanx at the web space, just distal to metacarpal/phalangeal (MCP) or metatarsal/phalangeal (MTP) joint

    Advance needle perpendicular to digit until bone is struck, aspirate and slowly inject 0.5 mL of lidocaine to anesthetize the dorsal nerve

    Withdraw needle slightly, then redirect and advance toward volar surface and slowly inject 1 mL of lidocaine

    Withdraw needle partially and redirect it medially over dorsal aspect of digit, aspirate and slowly inject lidocaine while withdrawing needle to anesthetize medial and dorsal aspect of digit

    Withdraw the needle

    Repeat procedure on medial side of digit at site of anesthetized skin

    Massage area of infiltrated skin for 15 to 30 seconds to ensure diffusion of the anesthetic

    Wait for 5 to 10 minutes to test for efficacy

 Four-sided Ring Block

    Advantages: Anesthetizes volar side of digits

    Disadvantages: May result in ischemic complications

    Perform traditional three-sided ring block

    Locate anesthetized volar–lateral aspect of proximal phalanx at the web space, just distal to MCP or MTP joint

    Advance needle medially, aspirate and slowly inject 0.5 mL of lidocaine to anesthetize the volar side while withdrawing needle

 Subcutaneous Block

    Prepare skin over volar surface at proximal skin crease

    Pinch skin distal to proximal skin crease

    Insert needle at midpoint of crease, aspirate and inject subcutaneous 1 to 2 mL wheal

    Massage injected area for 15 to 30 seconds to improve diffusion process

 Transthecal Approach

    Advantages: Single injection and low risk of neurovascular bundle injury

    Disadvantage: More painful to inject through volar surface

    Anesthetic is infused directly into the flexor tendon sheath at the proximal digital crease on volar surface

    Fill 5-mL syringe with lidocaine

    Insert 25-gauge needle at a 90-degree angle at the midpoint of the proximal digital crease and advance until bone is struck

    Withdraw needle approximately 2 to 3 mm (should be in flexor tendon sheath) and redirect at a 45-degree angle to the long axis of the digit

    Aspirate and inject 1.5 to 3 mL lidocaine while palpating tendon sheath with other hand; continue until resistance is felt

    After removing the needle, apply pressure over the tendon proximally to facilitate distal spread

    Wait for 2 to 3 minutes to test for efficacy of anesthesia

    Most effective for middle three fingers (FIGURE 52.2)

 Thumb Block

    All four digital nerves must be blocked for complete anesthesia of the thumb

    Locate the flexor pollicis longus on the volar aspect of the thumb at the level of the proximal thumb flexor crease

    The nerves lie immediately adjacent to this tendon

    Aspirate and inject 1 to 2 mL of lidocaine along both sides of the tendon (FIGURE 52.3)

 Wing Block

    Anesthetizes distal digit and nail bed

    Prepare the distal digit by using standard aseptic technique

    Insert 30-gauge needle perpendicular to the long axis of digit at a 45-degree angle at a point 3 mm proximal to the imaginary intersection of the lateral and proximal nail folds

    Aspirate and inject anesthetic across the dorsum of digit parallel to proximal nail fold

    Partially withdraw needle and redirect along lateral nail fold

    Aspirate and inject anesthetic along the lateral nail fold

    Repeat procedure on opposite side of digit if bilateral anesthesia is required (FIGURE 52.4)

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