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Strauss1 provided the first description of the
digital block in 1889 for the condition of an ingrown toenail, using 20% cocaine at the base and under the nail. In 1905, Braun reported the
synergistic advantage of adding epinephrine to local
anesthetics.2,3 However, the use of epinephrine in digital
block anesthesia has been avoided due to the theoretical risk of ischemia
and possible gangrene. More recently, however, Wilhelmi and
colleagues4 demonstrated the safety and efficacy of
epinephrine-containing local anesthetic for digital block, which made its
use only more controversial. Digital block is one of the most common nerve
block techniques, frequently used in the emergency department and primary
care settings for various procedures such as lacerations of the finger or
toe, nail removal, nail bed repair, paronychia drainage, removal of foreign
bodies, and any other painful procedures on digits.
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In 1990, approximately a century after the first publication of
traditional digital block, Chiu5 described a technique of
digital block that produced complete finger anesthesia with a single
injection into the flexor tendon sheath at the level of the distal palmar
crease. In anatomic studies he showed that after injection of
methylene blue into the flexor tendon sheath there was “complete staining
of the entire flexor tendon sheath and centrifugal diffusion of the blue dye
circumscribing the entire circumference of the proximal phalanx” (see
section on Transthecal Digital Block). The advantages of this technique are
(1) rapid onset of action, (2) only a small volume of anesthetic solution
required, (3) only a single injection required, and (4) absence of risk of
direct trauma to the neurovascular bundles.6–8 Although Chevaleraud and coworkers9 did not accomplish anesthesia of the
dorsum of the finger in all cases, some authors consider the transthecal
method to be as effective as a traditional digital nerve
block.10 Others have found that it results in anesthesia
comparable to the newer single-injection subcutaneous digital
blocks,11 both in experimental and clinical
situations.12,13 Transthecal anesthesia appears to be safe
and effective without a risk of any long-term damage to the tendon sheath.
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A digital block is the technique of blocking the nerves of the digits to
achieve anesthesia of the finger(s). This technique is simple to perform and
essentially devoid of systemic complications. It is a commonly used and
effective method of anesthesia for a wide variety of minor surgical
procedures on the digits. As such, this block should be in the armamentarium
of every anesthesiologist. Several different techniques of digital block and
their modifications are available; in this chapter, we chose to describe the
one that is most commonly used in our institution.
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The common digital nerves are branches of the median and ulnar nerves, which
divide in the distal palm into the volar aspect, tip, and nail bed area
(Figure 30–1). The main digital nerves, accompanied by digital
vessels, run on the ...