Nail Surgery Best Way to Obtain Effective Anesthesia Nathaniel J. Jellinek, MDa,b,c,*, Nicole F. Vélez, MDa KEYWORDS  Nail surgery  Nail biopsy  Dermatologic surgery  Nail biopsy  Digital anesthesia  Anesthesia of the nail unit  Anesthesia complications

KEY POINTS  Anesthesia of the nail unit requires a complete understanding of the anatomic and physiologic pathways of pain and the different anesthetic choices.  Buffering and warming the local anesthetic coupled with a slow rate of injection and small needle size, all drastically reduce pain of injection.  Local infiltrative anesthesia, termed a wing block, is an efficient and well-tolerated form of anesthesia; however, proper performance uses distracting anesthesia and slow rate of injection.  Traditional digital block involves injections at the base/sides of the digit and allowance of time for anesthesia to take effect.  Single-digit injection techniques (transthecal) are effective on the second to fourth fingers and provide complete anesthesia; however, postoperative pain may be more than with other techniques.

Videos of infiltrative anesthesia and nerve blockade of the bilateral dorsal/volar digital nerves accompany this article at http://www.derm.theclinics.com/

Successful nail surgery requires complete anesthesia. Sometimes it is this initial step in nail surgery that most intimidates the patient and, quite often, the physician. As such, mastery of digital anesthesia is a prerequisite to performing competent surgery on the nail apparatus. Administering digital anesthesia requires a multifaceted understanding of the anatomy of the digit, pathophysiology of pain, mechanisms of local anesthetics,

and nuances in both technique and preparation that maximize effectiveness of the procedure. Digital nerves run along each digit as paired parallel volar and dorsal nerves, terminating just beyond the distal interphalangeal joint (DIPJ), where they divide into 3 branches, supplying the nail bed, the digital tip, and pulp.1 There is no clear consensus on which specific branches innervate the tips for each digit. Generally accepted dogma is that the second to fourth fingertips are innervated by the volar branches, whereas the thumb

Conflicts of Interest: None. Funding Sources: None. Prior Presentation: None. a Dermatology Professionals, Inc, 1672 South County Trail, East Greenwich, RI 02818, USA; b Division of Dermatology, University of Massachusetts Medical School, Worcester, MA 01655, USA; c Department of Dermatology, The Warren Alpert Medical School at Brown University, Providence, RI 02903, USA * Corresponding author. 1672 South County Trail, Suite 101, East Greenwich, RI 02818. E-mail address: [email protected] Dermatol Clin - (2015) -–http://dx.doi.org/10.1016/j.det.2014.12.007 0733-8635/15/$ – see front matter Ó 2015 Elsevier Inc. All rights reserved.

derm.theclinics.com

INTRODUCTION, TREATMENT GOALS, AND PLANNED OUTCOMES

2

Jellinek & Ve´lez and fifth fingertips are innervated primarily by the dorsal branches. These sensory nerves carry the impulses from the many smaller nociceptors located in the nail unit and surrounding tissue to the brain. Cutaneous nociceptors provide an innate protective warning system for injury and consist of Pacinian corpuscles (movement-sensitive hair follicle receptors), Ruffini corpuscles (pressure sensitive mechanoreceptors), and free-ended nociceptors located at the dermoepidermal junction.2,3 There are 2 main classes of nerve fibers—fast/myelinated (A-d, carrying sharp pain) and slow/unmyelinated (C, carrying dull pain), which are activated by these receptors and transfer impulses of pain. Local anesthetics work by blocking the free nerve endings’ voltage-gated sodium channels and nerve depolarization, thus impeding transmission of pain. However, local anesthetics must first diffuse into the nerve cells through hydrophobic cell membranes. During anesthesia, patients experience pain from 2 distinct and unrelated procedures—the needle insertion and fluid infiltration. The former activates Pacinian corpuscles and mechanoreceptors, which transmit via A-d fibers to evoke the pinprick sensation, whereas the latter (through chemical irritation and rapid distention of tissue) activates mostly free-ending nociceptors and produces a more intense and continuous pain. Infiltrative anesthesia results from anesthesia of the smallest nerve fibers and blocking initial transmission of nociception, whereas nerve blocks affect larger, usually more proximal nerve fibers and require longer time of onset to diffuse into the nerves and block depolarization.

PREOPERATIVE PLANNING AND PREPARATION, PATIENT POSITIONING, “BEST WAY TO PERFORM” Several factors may impact the patient’s degree of pain from anesthesia and their postoperative

discomfort. These factors include both specific characteristics of the anesthetic (molecular composition, pH, temperature, addition of epinephrine) and choice of syringe and needle size, distracting stimuli, and technique of injection. Each of these considerations is highlighted individually below. Three main anesthetics are used in digital anesthesia—lidocaine, bupivacaine, and ropivacaine (Tables 1 and 2). Lidocaine is still the most widely used and has an unparalleled safety history. It is estimated that more than 300 million doses of lidocaine with epinephrine are injected in dental offices alone each year in the United States. Lidocaine is characterized by quick absorption and near instantaneous anesthesia of the minute nociceptors in the skin. The onset is faster (

Nail surgery: best way to obtain effective anesthesia.

Nail procedures require an effective and reliable approach to anesthesia of the distal digit. Several techniques have been described in the literature...
888KB Sizes 3 Downloads 9 Views