Chapter 242. Anatomy and Approach in Dermatologic Surgery

Dermatologic surgery has rapidly become a cornerstone of the practice of dermatology. Factors such as the epidemic of skin cancer, the interest in maintaining a youthful appearance for an aging population that is living longer, and the financial pressures to perform surgery in less expensive outpatient settings have led to an increase in the number of surgical procedures performed in dermatologic practice.

Anatomy is often called the language of surgery.1,2 Knowledge of anatomy is critical for a number of reasons, including communicating precisely with colleagues, performing efficient and safe procedures, obtaining optimal functional and aesthetic reconstruction, understanding the lymphatic drainage, and anticipating the metastatic spread of malignancies. As the majority of cosmetic and surgical procedures are performed on the face, and because of its complexity, this chapter focuses on the superficial cutaneous anatomy of this critical region.

Cosmetic Units and Landmarks

Landmarks and cosmetic units help localize areas of the face accurately and precisely for purposes of communication with colleagues and to perform the surgery itself. For instance, it is more helpful to describe a lesion on the face if it is said to be located on the “left nasal sidewall” versus left nose or “right triangular fossa” versus right ear. Cosmetic units are zones of tissue that share cutaneous features such as color, texture, pilosebaceous quality, pore size, and degree of actinic exposure. These cosmetic units are demarcated by junction lines that can be discrete (eyebrows) or subtle (nasofacial sulcus). Cosmetic units can also be further divided into subunits. Because of the tissue similarity, it is often best to reconstruct a surgical defect within a cosmetic unit or subunit or borrow tissue from nearby units. In addition, scar lines can be hidden easily in junction lines between the cosmetic units. The more complex regions of the face that have multiple subunits include the nose, ears, and lips (Figs. 242-1 and 242-2).

The subunits of the nose include the glabella (the area between the eyebrows), the root (the deep sulcus below the glabella and uppermost portion of the nose), dorsum or bridge (the area overlying the nasal bone), lateral side walls (the sides of the nose), nasal tip, the nasal ala (the nostril), alar groove and nasolabial crease (the grooves that demarcate the alae superiorly from the lateral nasal sidewall and alae inferiorly from the lip, respectively), and the columella (the mobile linear structure separating the alae inferiorly) (see Fig. 242-1).

The lateral surface of the ear is rimmed by the helix, a curved cartilaginous structure that begins at the crus just above the external auditory canal and continues around the ear to end at the fleshy lobule. The central concavity within which the external auditory meatus lies is the concha. The concha is divided by the crus of the helix into a superior portion, the cymba, and an inferior portion, the cavum. The posterior border of the concha is formed by another cartilaginous structure called the antihelix. Superiorly, the antihelix originates from two legs (crus is Latin for leg): (1) the superior crus and (2) inferior crus. The region between the crura is referred to as the triangular fossa. The groove between the helix and antihelix is the scaphoid fossa. The triangulated cartilaginous structure just anterior to the auditory canal is called the tragus, and just posterior to this is the triangulated end of the antihelix, referred to as the antitragus. The inferior region between the tragus and antitragus is the intertragic notch (see Fig. 242-2).

The cutaneous upper lip has a concave depression in the center, called the philtrum, which is bounded by two ridges, the philtral crests. There is a prominent crease, the mental crease, which divides the cutaneous lower lip from the chin. The boundary between the red mucosal surface of the lips and the cutaneous surface is called the vermillion border. The raised contoured area of the inferior portion of the philtrum is a critical aesthetic landmark known as the Cupid's bow (see Fig. 242-1).

Relaxed Skin Tension Lines

Relaxed skin tension lines (RSTLs) are another characteristic of the face that help guide surgical reconstruction and allow the structural camouflage of scar lines. RSTLs are creases on the face that form over time due to factors such as loss of elastic tissue tone, lengthening of the collagenous fibrous septae that connect the dermis to the underlying facial muscles, development of excessive skin, gravity, and ultraviolet radiation exposure. Fig. 242-3 illustrates a surgical defect on the upper lip of an elderly woman with prominent RSTL. RSTLs are most obvious on the face because unlike other muscles in the body that connect tendons and bones, facial muscles attach to the overlying skin. These lines can be induced by facial muscle movement in the young but inevitably become more pronounced with age. RSTLs usually run perpendicular to the underlying muscles. In most situations, the long axis of the excision should be placed parallel to the RSTL because they are often in the direction of the least tension for a scar. It is preferable to design flaps such that the majority of the scar lines fall within the RSTL.

Danger Zones

There are three main danger zones that are critical to understand while performing surgical procedures on the head and neck. Each of these zones involves a motor nerve and the muscles it innervates. It is important to confirm the proper function of these muscles before performing a procedure in these areas so that it can be readily determined whether an injury occurred during surgery.

Temporal Branch of the Facial Nerve

The temporal branch of the facial nerve is at greatest risk for injury where it crosses the zygomatic arch. Injury to the temporal branch of the facial nerve leads to an inability to elevate the eyebrows and brow ptosis and paralysis. Asymmetric appearance of the forehead can also occur because there will be a loss of the lines and wrinkles on the affected side. One easy method to delineate the danger area of the temporal nerve is to draw a line from the earlobe to the lateral edge of the eyebrow, and another line from the tragus to just above and behind the highest forehead crease (Fig. 242-4). In the area between these lines, over the zygomatic arch is where the nerve is superficial, and it is critical in this area to undermine just below the dermis in the superficial fat above the fascia.

Marginal Mandibular Nerve

Damage to the marginal mandibular nerve results in contralateral and upward pull on the mouth while the affected ipsilateral side of the mouth is fixed in a grimace with a lip droop. As it crosses the angle of the mandible at the inferoanterior border of the masseter, the marginal mandibular nerve is covered only by skin, subcutaneous fat, and fascia, which may be thin in this location, particularly in the elderly.

Spinal Accessory Nerve

Injury to the spinal accessory nerve leads to the paralysis of the trapezius with winging of the scapula, shoulder drop, inability to shrug the shoulder, difficulty with abducting the arm and chronic shoulder pain. Transection of the spinal accessory nerve can occur when operating in the posterior triangle of the neck. This region is delineated by the clavicle inferiorly, the sternocleidomastoid muscle anteriorly, and the trapezius muscle laterally and posteriorly. One can anticipate the location of the spinal accessory nerve by drawing a line connecting the angle of the mandible with the mastoid process. A vertical line is then drawn from the midpoint of this line 6 cm inferiorly. The point at which this line intersects the posterior border of the sternocleidomastoid muscle is Erb's point. The spinal accessory nerve emerges approximately from this point and lies superficially here, covered only by skin and fascia.

Undermining Planes

Superficial Musculoaponeurotic System

The term fascia refers to connective tissue that contains both fibrous and fat tissue in various amounts. Superficial fascia is the subcutaneous tissue that is immediately below the dermis. The deep fascia consists of more compact and highly organized collagen fibers. The superficial musculoaponeurotic system (SMAS) is the fascial system that envelops the muscles of the face. It stretches over the cheeks between the temporalis and frontalis muscles above and the platysma muscle below. The SMAS also attaches to the orbicularis oculi muscles anteriorly, the trapezius muscle posteriorly, and includes the fascia of the forehead and galea of the scalp. Most of the superficial muscles of the scalp and face insert into the skin either directly through fibrous bands running in the subcutaneous tissue or indirectly by attachment to the SMAS, which, in turn, is attached to the skin. In the lateral areas of the face, the SMAS is organized and more visible but becomes less discrete medially. Because of its attachment to the skin superficially and muscles deep, the SMAS coordinates a wide range of facial expressions. In addition, the SMAS is an important landmark because most major arteries and nerves run within or deep to it. Thus, dissection above the SMAS allows one to safely avoid injuring branches of the facial nerve.

Scalp

The scalp is classically divided into five layers that are often referred to by the mnemonic SCALP. These layers from superficial to deep are: skin, subcutaneous tissue, aponeurosis (galea aponeurotica), loose connective tissue, and periosteum. Because the majority of the nerves and vessels of the scalp are superficial to the subgaleal space, this is an ideal undermining plane. However, it is also known as the danger zone because hematomas and infection can develop here and pass through the emissary veins into the meninges.

Forehead

The forehead is best undermined immediately above the superficial fascia of the frontalis muscle. There may be little subcutaneous fat in this area. The temple should be undermined in the high fat/subdermal region to avoid damaging the temporal branch of the facial nerve.

Eyelids

The eyelids possess the thinnest skin of the body. The skin of the eyelids lies directly on the orbicularis muscle. Undermining should be performed above the muscle fascia to avoid causing significant bleeding and scars/contractures that can lead to ectropion.

Chin and Lips

The large, thick muscles of the lips and chin can make undermining challenging. The chin, in particular, has muscles broadly attached directly to the skin. Sharp undermining performed just above the superficial muscular fascia is appropriate. These areas are at high risk for bleeding, made even more precarious by functions such as talking and chewing.

Nose

The nose requires different levels of undermining in different regions. The dorsal nose can be easily undermined above the periosteum, especially when performing reconstruction with flaps. The distal, more sebaceous portion of the nose must be undermined in the subfibrofatty layer to allow the greatest tissue movement.

Cheeks

The cheeks can be safely mobilized in the high or mid subcutaneous fat. Care must be taken when undermining in the hair-bearing regions of the cheek in men, however. Here, undermining should be performed in the deep subcutis to avoid transecting hair follicles.

Neck

The neck can be safely undermined while staying above the superficial fascia. One must be careful in the posterior triangle of the neck. This region is delineated by the clavicle inferiorly, the sternocleidomastoid muscle anteriorly, and the trapezius muscle laterally and posteriorly. The spinal accessory nerve lies superficially here, covered only by skin and fascia.

Sensory Nerves

The trigeminal nerve (cranial nerve V) provides the majority of the sensory innervation of the face (Fig. 242-5). It exits the skull via three foramina located bilaterally in the midpupillary line, the supraorbital, infraorbital, and mental foramina. The first branch, the ophthalmic nerve (V1), has several branches that supply the innervation to the superior portion of the face: the supraorbital, supratrochlear, infratrochlear, external nasal, and lacrimal nerves. The supraorbital (lateral) and supratrochlear (medial) nerves supply the forehead and anterior scalp and are branches of the frontal nerve (the largest branch of the ophthalmic nerve). They exit from two notches along the orbital rim: (1) supraorbital foramen or notch laterally, and (2) supratrochlear notch, medially. The infratrochlear branch (of the nasociliary nerve) supplies the glabella, nasal root, and bridge. The external nasal branch (or the dorsal nasal nerve) is a branch of the anterior ethmoidal nerve of the nasociliary branch of V1. The external nasal branch supplies the dorsal nose and provides the anatomical explanation of Hutchinson sign that can occur in some cases of herpes zoster of the ophthalmic nerve. Vesicles on the nasal tip indicate that the eye may be involved because the nasociliary branch of V1 sends branches both to the nasal tip and the cornea. The lacrimal branch supplies sensation to the upper eyelid.

The second branch of the trigeminal nerve is the maxillary nerve (V2). The maxillary nerve supplies sensation to the lateral nose, lower eyelid, superior cheek, and anterior temple. The maxillary nerve gives off two main branches that supply the skin of the face. The zygomatic branch of the maxillary nerve gives rise to the zygomaticofacial nerve, which exits the skull through the lateral zygomatic bone and supplies a small area of the lateral canthus. In addition, the zygomatic branch also gives rise to the zygomaticotemporal nerve, which exits the skull through the anterior temporal fossa and supplies skin of the anterior temporal region. The largest branch of the maxillary nerve is the infraorbital nerve that exits the skull through the infraorbital foramen of the maxilla. This supplies sensation to the eyelid and superior cheek.

The third branch of the trigeminal nerve is the mandibular nerve (V3). Its branches provide sensory innervation to the lower lip, chin, mandibular and preauricular cheek, anterior ear, and the central temporal scalp. The mandibular nerve gives off three major cutaneous branches: (1) the auriculotemporal, (2) buccal, and (3) mental nerves. The auriculotemporal nerve innervates most of the temple, the temporoparietal scalp, the anterior ears, parts of the external ear canal, and the tympanic membrane. The buccal nerve lies deep to the parotid gland and supplies the skin over the buccinators, buccal mucosa, and the gingiva. The mental nerve exits through the mental foramen and is a continuation of the inferior alveolar nerve. The mental nerve supplies sensation to the lower lip and chin.

Muscles

The scalp has two muscles overlying it, the frontalis anteriorly and the occipitalis posteriorly. These muscles are joined by a thick fascia centrally over the scalp, the galea aponeurotica. The frontalis muscle also covers the forehead and elevates the eyebrows. The eyebrows move medially and downward with contraction of the corrugator supercilii muscles. The procerus lies between the supercilii muscles and draws the skin of the forehead inferiorly to create the horizontal creases at the root of the nose. The orbicularis oculi muscle surrounds the eye and consists of an orbital and palpebral portion. The orbicularis oculi muscle serves to close the eyes with the palpebral part with both reflexive and voluntary control and the orbital part with voluntary control. The central sphincter-like muscle around the mouth is the orbicularis oris. This muscle helps purse the lips to form certain sounds and whistle. The lip depressors are depressor anguli oris, depressor labii inferioris, and the mentalis. The lip elevators are the zygomaticus major, zygomatic minor, levator anguli oris, levator labii superioris, and the levator superioris alaeque nasi. The risorius helps retract the corner of the mouth. The buccinators and masseter muscles help with mastication (Fig. 242-6).

Motor Nerves

The facial nerve (cranial nerve VII) provides innervation to all the muscles of facial expression. It exits the skull via the stylomastoid foramen, which lies deep in the infra-auricular sulcus and anterior to the mastoid process. The facial nerve enters the parotid gland at the level of the intertragic notch and usually divides into five branches within the substance of the gland. The well-known mnemonic “to Zanzibar by motor car” can be used to remember the five main branches: (1) temporal, (2) zygomatic, (3) buccal, (4) mandibular, and (5) cervical. For the most part, these nerves enter the muscles they innervate posteriorly and deep. A nice rule of thumb is that if one transects a nerve lateral to the midpupillary line, permanent paralysis can result and if the nerve is cut medial to this demarcation, most nerves will regenerate or have arborizations that will help provide additional innervation.

The temporal branch of the facial nerve exits the superior part of the parotid gland and crosses the zygomatic arch to innervate the frontalis, upper portion of the orbicularis oculi, and corrugator supercilii. Injury to the temporal branch leads to an inability to raise the eyebrows and brow ptosis. The zygomatic branch innervates the orbicularis oculi, nasal muscles, lip elevators, and the buccinators. Damage to the zygomatic nerve results in lower eyelid ptosis and an inability to close the eyes completely. The buccal branch also innervates the buccinators and lip elevators, as well as the orbicularis oris and risorius. Damage to the buccal branch leads to an inability to whistle. The marginal mandibular branch crosses the angle of the mandible at the inferior-anterior border of the masseter. It innervates the depressors of the mouth.

Vascular Supply

The blood supply of the face is almost entirely derived from branches of the external carotid artery (Fig. 242-7). Just posterior and medial to the angle of the mandible, the facial artery branches off the external carotid artery. The facial artery continues anteriorly and superiorly toward the angle of the mouth, giving off the inferior labial artery and superior labial arteries that supply the lips. The continuation of the facial artery in the nasofacial sulcus is called the angular artery. The angular artery continues superiorly to enter the orbit immediately over the medial canthal tendon where it anastomoses with the ophthalmic artery, a branch of the internal carotid artery. After giving off the facial artery, the external carotid artery then passes deep to the sternocleidomastoid muscle and enters the body of the parotid gland where it gives off the posterior auricular artery that supplies the postauricular scalp, the maxillary artery, and the superficial temporal artery. The terminal branch of the maxillary artery exits the infraorbital foramen with the infraorbital nerve as the infraorbital artery to supply the lower eyelids and infraorbital cheek.

The terminal branches of the internal carotid artery are the ophthalmic artery branches, the supraorbital artery, and the supratrochlear artery. The supraorbital artery emerges from the supraorbital foramen, whereas the supratrochlear artery emerges more medially. The internal and external carotid systems join in two places: (1) where the supratrochlear branch and the dorsal nasal artery anastomose with the angular artery and (2) where the forehead branches of the supraorbital and supratrochlear arteries anastomose with branches of the superficial temporal artery.

The veins of the face parallel and lie posterior to the arteries. Unlike the veins of the trunk and extremities, facial veins have no valves. This allows blood to flow in either direction. Thus, in the central face where there are anastomoses between branches of the ophthalmic vein and of the angular vein, infection has easy access to travel along the ophthalmic vein to the cavernous sinus. The angular vein also communicates with the deep facial vein and pterygoid plexus.

Lymphatics

The lymphatic vessels of the face generally drain from superficial to deep and medial to lateral and caudad. While the general drainage patterns are described here, variations can occur. The posterior scalp drains to the postauricular and occipital nodes. The lateral and superior face, the forehead, and the lateral eyelids drain to the parotid nodes. The medial and inferior face, including the medial eyelids and lateral lips, drain to the submandibular nodes. The middle two-thirds of the lower lip and the chin drain to the submental nodes. These nodes can be optimally palpated by performing a bimanual exam with a gloved hand feeling through the floor of the mouth.

The lymph nodes of the head and neck eventually drain into a terminal series of nodes (deep cervical nodes) and finally into the lateral internal jugular chain.

Preoperative assessment is critical for a successful procedure. It allows one to anticipate and possibly correct factors that predispose to adverse outcomes and minimize complications. A fairly thorough medical, drug, and medication allergy history provides an accurate picture of the patient's health status. Questioning the possibility of pregnancy in women of childbearing age should not be overlooked, as local anesthetics and antibiotics may be contraindicated. Patients with inherited bleeding disorders can also be identified and, when possible, given clotting factors to correct for these disorders. Uncontrolled hypertension may predispose to increased intraoperative and postoperative bleeding. In addition, poorly controlled diabetes and immunosuppression with use of systemic steroids for medical conditions, such as autoimmune disorders or organ transplantation, may affect healing time. Information from the social history can also have a bearing on the surgery. For instance, healing can be adversely affected if the patient smokes, and this may impact the decision to perform a flap or graft. Alcohol consumption can increase the risk of bleeding because of its qualitative effect on platelets. Finally, knowledge of the patient's resources and support at home is helpful when providing instructions for postoperative care.

Antibiotics

A well-planned and executed surgical procedure can be significantly compromised by an infection. Infections can lead to poor cosmesis, inconvenience, added expense, and patient dissatisfaction. Because every surgical procedure violates the epidermal barrier, no surgical procedure is absolutely sterile. Hence, all surgical wounds are contaminated by bacteria because of the inevitable resident flora in humans. However, not all contaminated wounds become infected. Infection depends on a large number of factors: the pathogenicity of the microbe, the quantity of the microbe, the length of surgery/timing of infection, the presence of foreign material (sutures, devitalized tissue), presence of dead space, poor suturing/surgical technique, poorly designed reconstruction, compromised vascular supply, and the host and wound's resistance to infection. Usually a wound that contains greater than 105 bacteria per gram of tissue is considered infected.3 The American College of Surgeons has defined wounds as: clean (nontraumatic, without break in aseptic technique), clean-contaminated (minor break in aseptic technique, wounds in oral cavity, axillae, perineum), contaminated (acutely inflamed, major break in aseptic technique), and dirty (encountering pus, fecal, or urinary discharge). Antibiotics can be considered for some clean-contaminated, contaminated, and dirty wounds. Most wounds in dermatologic surgery are clean-contaminated wounds and do not require antibiotics. The most common organism is Staphylococcus aureus and a first generation cephalosporin (or clindamycin for the penicillin allergic) is appropriate when necessary. Studies show that to prevent or change the course of infection, antibiotics must be given within 2–3 hours after inoculation and that antibiotics give maximal suppression against infection if given before bacteria colonize tissue. In addition, there is concern that, with increasing time, the wound is sealed off with blood clots and fibrous exudates, and the antibiotic is unable to reach the wound effectively. Routine use of antibiotics postoperatively is discouraged due to the risk of encouraging the development of antibiotic resistance amongst bacteria.

Although specific criteria for the use of prophylactic antibiotics to prevent endocarditis do not exist for dermatologic procedures, most dermatologic surgeons follow the revised American Heart Association guidelines. Cardiac conditions for which prophylaxis is reasonable include prosthetic cardiac valve, previous infective endocarditis, congenital heart disease (limited particularly to unrepaired cyanotic congenital heart disease, completely repaired congenital heart defect with prosthetic material during the first 6 months after the procedure, repaired congenital heart disease with residual defects at the site or adjacent to the site of a prosthetic patch or prosthetic device) and cardiac transplantation recipients who develop cardiac valvulopathy. Appropriate antibiotic regimen for prophylaxis for cutaneous procedures is 2 g of cephalexin (or 600 mg of clindamycin in penicillin-allergic patient) 1 hour before the procedure.4

Medications

The use of blood anticoagulants, such as warfarin, dipyridamole, clopidogrel, and aspirin, are common in the aging population. In the past, patients were often told to discontinue their blood thinners before surgery. However, recent reports show that discontinuing these medications prior to dermatologic surgery can lead to episodes of thrombotic events such as stroke and pulmonary embolism.5 Furthermore, remaining on such medications does not lead to significant adverse events. However, patients who are taking aspirin and other nonsteroidal anti-inflammatory drugs for nonphysician-recommended “preventive” purposes are advised to discontinue these drugs preoperatively. These agents are typically withheld for 7–14 days prior to surgery.

Many patients may be taking herbal or over-the-counter drugs that also interfere with clotting. These are not often considered “drugs” by patients, and thus they may not volunteer taking such supplements unless they are specifically asked. Some common preparations in this category include vitamin E, garlic, gingko, ginseng, feverfew, or ginger. Alcohol can also interfere with platelet aggregation, and it is important to instruct patients to avoid drinking a few days before and after the surgery. Most dermatologic surgeons advise patients to avoid alcohol, herbal products, and nutritional supplements several days before surgery.

Nonselective β blockers (i.e., propanolol) can occasionally potentiate the effect of epinephrine and lead to complications such as malignant hypertension and bradycardia.

Other preoperative considerations include latex allergy or allergy to topical antibiotics or adhesives in tapes. Use of systemic steroids can prolong the wound healing time.

Pacemakers and Defibrillators

Electrosurgery is widely used in dermatologic surgery to obtain hemostasis. However, electrosurgery can disrupt the function of pacemakers and implantable cardioverter-defibrillators (ICDs) by oversensing, inhibiting firing, device reprogramming, battery depletion, or direct damage to the device.6 Thus, it is important to identify patients with such devices and to use proper precautions. Fortunately, newer pacemakers and ICDs have improved shielding and are more resistant to the electromagnetic interference that can be produced by electrosurgery. ICDs are more sensitive to electromagnetic interference, and this interference can cause the defibrillator to discharge, leading to significant morbidity and possible mortality for the patient. If electrosurgery is necessary, recommendations, such as using short bursts of electricity (less than 5 seconds) and avoiding its use directly around the area of the pacemaker, may minimize risks. In addition, bipolar electrosurgery creates little interference and is safer. Heat cautery does not cause any interference and is the safest but is not as effective for hemostasis with larger or complicated procedures.

Smoking

Smoking should also be discussed preoperatively with patients. Tobacco use creates vasoconstriction, which impairs wound healing and jeopardizes the reconstruction, especially with more complicated procedures such as flaps and grafts. Patients should be strongly encouraged to cease tobacco use at least 1 week before surgery and 1 week postoperatively. It is also important to clarify that a nicotine patch is not ideal, and patients must avoid nicotine exposure through patches or gum.

Surgical History

A discussion of scars and healing after previous procedures can be informative for the patient and surgeon. The physician can determine if the patient is predisposed to forming hypertrophic scars or keloids and plan reconstruction and postoperative care appropriately. The patient may have a misunderstanding of wound healing and feel that a well-healed visible scar on a high-tension area is a keloid. This can be an opportunity to anticipate patient expectations and educate them on the process of wound healing.

Skin Preparation and Aseptic Technique

The normal skin is colonized by a host of bacteria, primarily aerobic cocci. Staphylococcus aureus is the most common cause of cutaneous wound infections in dermatologic surgery. Other bacteria commonly identified on the skin include Staphylococcus epidermidis, Pseudomonas, Propionibacterium, streptococci, and micrococci. Pseudomonas is frequently the pathogen identified in infections of cartilaginous regions such as the ear. The aim of aseptic solutions is to significantly reduce the amount of normal bacterial flora, as complete sterilization of the skin is not possible due to the presence of bacteria in pilosebaceous units. The ideal antiseptic would be nonirritating, nontoxic, nonsensitizing, be effective against all resident and transient microbes, and long-lasting. In prepping the field, shaving the hair creates multiple superficial microabrasions in which bacteria may reside and is associated with an increased incidence of local wound infections. Hair removal, if needed, has the lowest risk of associated infection if done by clipping or depilatory agents.7

Iodophors, which act through oxidation of cell membranes by free iodine, are common topical antiseptics. The most common form of this antiseptic is povidone-iodine. This antiseptic has broad antimicrobial activity against both Gram-positive and Gram-negative bacteria, as well as fungi, viruses, and mycobacteria. Iodophors have bactericidal activity that persists for several hours after application. On contact with blood or serum, the bactericidal activity is lost, but some bacteriostatic activity is retained. This class offers relatively rapid onset of action with full bactericidal activity being achieved within 1–3 minutes for most bacteria. Side effects of povidone-iodine include allergic contact dermatitis, irritant contact dermatitis, and possible tissue necrosis with prolonged exposure to large amounts in open wounds.

Chlorhexidine also functions through disruption of cell membranes. It has broad antimicrobial activity with excellent Gram-positive coverage and very good Gram-negative activity. It has some degree of activity against viruses but little effect on mycobacteria or fungi. Chlorhexidine offers a more rapid onset of action than povidone-iodine, providing almost immediate bactericidal activity upon application, which persists for many hours after application. It provides superior decontamination of the skin as compared to iodophors with resulting decreased rates of postoperative infection.8 As a result, chlorhexidine is preferred over povidone-iodine as a surgical antiseptic agent if the surgical site does not limit its usage. The primary side effect of chlorhexidine is the potential for ototoxicity and keratitis. As a result, it should not be used around the eyes or ears. Similar to iodophors, prolonged exposure of chlorhexidine in open wounds has been reported to be toxic to the tissue.

Isopropyl alcohol and ethyl alcohol are effective antiseptics for minor skin procedures. They function through the denaturation of microbial proteins. They display good activity against Gram-positive and Gram-negative bacteria, mycobacteria, viruses, and fungi. Alcohols have a rapid onset of activity at the site of application, but there is no persistence of this activity over time. The antimicrobial activity of alcohols is not as extensive as that of chlorhexidine or iodophors. In addition, the flammable nature of alcohols limits their use in procedure requiring electrocautery.

Hexachlorophene is rarely used as a skin antiseptic solution. It has excellent Gram-positive activity but limited activity against Gram-negative organisms or fungi. It is also readily absorbed through the skin and has the potential for neurotoxicity, especially in infants.

Local Anesthesia

Effective anesthesia is critical to the successful performance of dermatologic surgery. The overwhelming majority of cutaneous surgical procedures can be performed with local anesthesia. Local anesthesia provides the benefits of rapid onset of action, ease of use, decreased cost, and minimal associated morbidity and mortality.

Nerves transmit stimuli through the opening of sodium channels, which results in an influx of sodium ions into the nerve cell. This influx results in depolarization of the axon generating an action potential. Local anesthetics exert their effect on nerves by blocking the sodium channels on nerve axons. This blockage inhibits depolarization and the formation of an action potential. Local anesthetics affect the smaller unmyelinated C-type nerve fibers, which carry the sensation of pain and heat, more rapidly and effectively than myelinated A-type nerve fibers, which transmit the sensation of pressure and innervate muscle fibers. Thus, adequate anesthesia can be achieved while motor function and pressure sensation are maintained.

Local anesthetics structurally are composed of three subunits: (1) a hydrophobic aromatic ring, (2) a hydrophilic amine group, and (3) an intervening group connecting the hydrophobic and hydrophilic units. The hydrophobic aromatic ring is responsible for the molecule's ability to diffuse through axonal membranes. The hydrophilic amine maintains the solubility of the compound in aqueous solution and accounts for blockage of the sodium channels of nerve axons. The region connecting the hydrophilic and hyphobic regions may be either an amide group or an ester group. Amide anesthetics, which include lidocaine, prilocaine, bupivacaine and mepivacaine, are metabolized in the liver through dealkylation and hydrolysis by microsomal enzymes. Ester anesthetics, which include procaine, benzocaine, tetracaine, and cocaine, are metabolized by plasma pseudocholinesterase and are excreted renally.

Selecting the Appropriate Anesthetic

The nature of the procedure determines which local anesthetic is ideal (Table 242-1). The primary variables to consider in choosing between anesthetics are the onset of action and the duration of anesthesia. Patient factors to consider in this selection are a history of allergy to an anesthetic class or renal or hepatic impairment. For simple biopsies and excisions, a rapid-onset anesthetic, like lidocaine, with medium duration of action provides effective anesthesia. For more extensive procedures, an anesthetic with a longer duration of action, such as bupivacaine, may be desired. Some practitioners choose to mix a rapid-onset anesthetic with one of long duration into one injectable solution.

Epinephrine

Local anesthetics, with the exception of cocaine, are vasodilators. This vasodilatory effect produces unwanted bleeding at the operative site. Epinephrine with its potent vasoconstrictive effects is often added to local anesthetic preparations to reduce bleeding. Concentrations ranging from 1:100,000–1:500,000 are effective in reducing bleeding at the surgical site. In addition to its hemostatic effect, epinephrine reduces the dispersion of the local anesthetic from the operative site. This prolongs the duration and efficacy of the anesthesia by 100%–150%. It also limits the potential for systemic toxicity, as less anesthetic is allowed to enter the systemic circulation.

Epinephrine is a potent agonist of α- and β-adrenergic receptors. Absolute contraindications to its use with local anesthetics are pheochromocytoma and hyperthyroidism. Relative contraindications to the use of epinephrine include severe coronary artery disease, uncontrolled hypertension, peripheral vascular disease, pregnancy, and acute angle glaucoma. In addition, epinephrine should be used with caution in patients on β blockers, monoamine oxidase inhibitors, phenothiazines, and tricyclic antidepressants as these individuals demonstrate greater sensitivity to its effects. Although uncommon, severe hypertension may be encountered in patients on β blockers due to the unopposed α-receptor stimulation of the epinephrine.

The use of epinephrine-containing local anesthetics on anatomic regions with minimal collateral circulation, such as the digits, penis, and nasal tip, is a matter of controversy. Reports of local tissue necrosis in these areas with limited perfusion attributed this result to the potent vasoconstrictive effects of the epinephrine. More recent observations indicate this necrosis to actually be the result of excessive volume of anesthetic used, which physically tamponades the vessels. Thus, local anesthetics with epinephrine are now considered safe for use on the digits, penis, and nasal tip, when used judiciously in small volumes. Consideration may be given to using a lower concentration of epinephrine (1:500,000) for those sites with severely limited perfusion.

Self-limited, systemic side effects may also be experienced with the administration of epinephrine-containing anesthetics. These include anxiety, fear, palpitations, tachycardia, diaphoresis, tremor, and hypertension. Serious side effects of excessive epinephrine administration include arrhythmias, cardiac arrest, and cerebrovascular hemorrhage. These serious side effects are extremely rare when used at appropriate dosages in individuals without significant contraindication.

Side Effects

The most common side effect of local anesthetics is the pain of its administration. Premixed local anesthetic preparations containing epinephrine are manufactured as an acidic solution with a pH of between 3 and 5 in order to maintain the stability of epinephrine. Injection of this acidic solution into tissue often produces significant discomfort. To avoid this, the pH of the solution can be adjusted before injection closer to the physiologic pH of 7.4 through the addition of sodium bicarbonate. The standard formula for this is the combination of one part of 8.4% sodium bicarbonate with 10 parts lidocaine. This buffered solution must be used soon after preparation as the epinephrine gradually degrades at a rate of approximately 25% per week. Alternatively, the epinephrine and anesthetic may also be mixed immediately before use, which also provides a neutral solution. In each instance, the neutral or slightly alkaline solution has the added advantages of quicker onset of action and increased anesthetic effect as the pH of the solution is closer to the pKa of the anesthetic, meaning more of the anesthetic is in its active ionized cationic form.

Slow injection of the anesthetic through a small gauge needle (27 gauge to 30 gauge) also minimizes the pain of injection. Smaller syringes, such as 1–3 mL, create less pressure at the site of anesthetic administration. Based on the gate theory of pain perception, repeated pinching or vibration of the immediate surrounding area lessens the perception of the stick at site. Verbal distraction of the patient is also useful in lessening the anxiety and discomfort of the anesthetic.

Injection of anesthetic into the subcutaneous tissue is less painful than injection into dermal tissue; however, a quicker onset of action and longer duration of anesthesia are observed with dermal injection. If a large area is to be anesthetized, the initial injection should be placed near the origination of sensation and proceed distally. Subsequent injections, if necessary, should be made through previously anesthetized tissue. For large areas, consideration should also be given to the use of nerve blocks to minimize discomfort.

One side effect of local anesthetic administration that is not uncommon is the vasovagal reaction. This may be manifested as pallor, weakness, bradycardia, hypotension, diaphoresis, and nausea. Placement of the patient in Trendelenburg position usually results in complete resolution of these symptoms within several minutes. A cool compress on the forehead and fanning the patient are often helpful in comforting the patient during this episode. Patients should be injected in a recumbent or Trendelenburg position to minimize the likelihood of a vasovagal response. These positions also allow providers to be better prepared to deal with the reaction should it occur. Pain and anxiety of anesthetic injection can precipitate a vasovagal reaction; thus, the aforementioned techniques for lessening the discomfort of injection are critical in reducing the likelihood of a vasovagal response.

Allergy to a local anesthetic is an uncommon side effect in dermatologic surgery. Amide anesthetics are more likely to be the culprit of allergic reactions whereas allergic reactions to ester anesthetics are exceedingly rare. True allergic reactions are typically immediate type I immunoglobulin E-mediated reactions, which may produce urticaria, angioedema, bronchospasm, tachycardia, hypotension, and, possibly, cardiovascular collapse. For severe reactions, administration of epinephrine and cardiopulmonary support is indicated. Less commonly, type IV-delayed hypersensitivity reactions may be observed. These present similar to an allergic contact dermatitis in the days following the injection of the anesthetic.

For those patients in whom an allergy to an anesthetic is unclear, intradermal prick testing to ester anesthetics, amide anesthetics, and any added preservatives, such as sodium metabisulfite and methylparabens may be helpful. Alternatively, for smaller procedures, the intradermal injection of diphenhydramine hydrochloride solution provides temporary anesthesia without risk of an allergic response. Antihistamine side effects, including significant drowsiness, may be encountered with its use. The intradermal injection of normal saline with preservative may also be used for very brief procedures. The temporary anesthesia it provides is attributed to a combination of the tamponade effect on nerves and the mild anesthetic effect of the preservative benzoyl alcohol.

Anesthetic toxicity is a rare complication given the typical volumes required for dermatologic surgery. Signs of toxicity are usually not observed with dosages less than 5.0 mg/kg of plain lidocaine and 7.0 mg/kg of lidocaine with 1:100,000 epinephrine. For tumescent anesthesia, the maximum safe dose increases to 55.0 mg/kg of 0.05% –0.1% lidocaine with 1:1,000,000 epinephrine. The initial presenting signs are circumoral numbness and tingling, tinnitus, lightheadedness, nausea, and numbness of the distal extremities. With additional anesthetic, more extensive central nervous system depression may occur with hallucinations, seizures, and respiratory depression. Cardiovascular toxicity may also occur, but does so at much higher levels of anesthetic than the initial central nervous system toxicity. The manifestations include hypotension, arrhythmias, and cardiac arrest.

Both central nervous system and cardiovascular toxicity are directly related to serum levels of the anesthetic. Thus, direct intravenous or intra-arterial injection is to be avoided when anesthetizing an area. This can be done by drawing back on the syringe after needle insertion prior to infiltration of the anesthetic to confirm that the needle is not in a vascular structure. The risk of toxicity can be elevated by other medical problems affecting the metabolism of the anesthetic. In particular, patients with liver disease experience increased serum levels of amide anesthetics due to an impaired ability to metabolize and clear the anesthetic. Thus, a lower dosage of an amide anesthetic or a switch to an ester anesthetic is advisable in these patients.

Topical Anesthetics

Several local anesthetics are also available as topical preparations. When used properly, these agents provide suitable anesthesia for minor dermatologic procedures, such as shave biopsies or superficial laser treatments. Their efficacy on normal skin is limited by their ability to penetrate the stratum corneum. Thus, most of the preparations require extended application times and/or occlusion for effectiveness.

LMX is a topical lidocaine cream in a liposomal vehicle. It is available in 4% and 5% concentrations. Eutectic mixture of local anesthetics (EMLA) cream consists of a combination of 2.5% lidocaine and 2.5% prilocaine. LMX and EMLA have been shown to be more effective than other topical preparations of 4% tetracaine gel and Betacaine-LA (a mixture of prilocaine and lidocaine in a liquid paraffin ointment). LMX typically requires an application time of 30 minutes with or without occlusion, whereas EMLA requires 1 hour with occlusion. Multiple studies have demonstrated the 30-minute application of LMX without occlusion to provide equal anesthesia as 1-hour application of EMLA with occlusion. Caution should be exercised in the use of large amounts of prilocaine-containing topical preparations in infants or those with an impaired skin barrier, as prilocaine has the potential to induce methemoglobinemia.

Cryogens, such as ethyl chloride, also provide brief anesthesia at a site for minor procedures or the insertion of a needle. Similarly, an ice cube placed on an injection site often significantly reduces the discomfort of injection in the anxious patient.

Mucosal membranes are readily anesthetized using topical preparations due to the ease of penetration in the absence of a stratum corneum. Tetracaine or proparacaine drops rapidly provide effective anesthesia of the conjunctiva and cornea for insertion of eye shields. Benzocaine and lidocaine preparations provide prompt anesthesia for intraoral procedures or before nerve blocks.

Nerve Blocks

The use of regional nerve blocks can be of immense value to the dermatologic surgeon. Regional nerve blocks allow large cutaneous areas to be anesthetized with small volumes of anesthetic. They are based on the injection of a local anesthetic into the immediate vicinity of a sensory nerve as it emerges from deeper planes of tissue. This provides effective anesthesia for the patient while minimizing the discomfort of multiple injections. Nerve blocks have the added benefits of limiting the possibility of anesthetic toxicity as well as minimizing tissue distortion. The primary risk of nerve blocks is nerve trauma with resultant neuropraxia.

The standard anesthetic used for regional blocks is 1% lidocaine with 1:100,000 epinephrine; however, bupivacaine may be added if more lasting anesthesia is desired. A 1 inch, 30 gauge is suitable for the performance of most nerve blocks. The proper execution of nerve blocks is predicated on a thorough knowledge of the anatomy of the region being anesthetized.

The cutaneous sensation of the face is primarily supplied by the trigeminal nerve, with a small fraction of the periphery being supplied by the cervical plexus. As its name implies, the trigeminal nerve consists of three major divisions: (1) the ophthalmic (V1), (2) maxillary (V2), and (3) mandibular (V3) divisions. Each of these divisions has major branches, which are amenable to regional nerve blocks.

The ophthalmic division of the facial nerve gives off the supraorbital, supratrochlear, and infratrochlear nerves. The supraorbital nerve exits through the supraorbital foramen, which is a readily palpable bony notch located along the orbital rim just medial to the midpupillary line. The supratrochlear branch exits along the orbital rim approximately 1.5 cm medial to the supraorbital notch. The infratrochlear nerve exits just above the medial canthus. All three of these branches can be anesthetized with a single injection by inserting the needle 2–3 mm lateral to the supraorbital notch and advancing medially through the subcutaneous tissue to the medial canthus. The anesthetic is then injected as the needle is slowly withdrawn in one smooth motion. This single injection provides anesthesia to the ipsilateral forehead, frontal scalp, upper eyelid, medial canthus, and superior nasal sidewall and root.

The infraorbital nerve, a branch of the mandibular division, exits through the infraorbital foramen, which is located in the midpupillary line approximately 1 cm below the infraorbital rim. This nerve may be blocked by either an intraoral or a percutaneous approach. The percutaneous method involves insertion of the needle directly over the infraorbital foramen and advancement directly down to the maxillary bone, where the anesthetic is delivered. With the intraoral approach, the sulcus located just above and lateral to the canine tooth is identified by manual palpation. The needle is inserted in the superior portion of this sulcus and advanced upward approximately 1 cm in the midpupillary line. At this position, the anesthetic is slowly injected. The intraoral approach is less painful than the percutaneous one, and may be further aided by the use of a topical lidocaine or benzocaine gel on the oral mucosa. This block provides anesthesia to the ipsilateral lower eyelid, medial cheek, upper lip, and upper teeth.

The mental nerve is a branch of the mandibular division, which exits through the mental foramen just medial to the midpupillary line. This nerve is easily accessed via an intraoral injection. It is located just opposite of the first bicuspid on the mucosa of the lower lip, and is often visible to the naked eye as a thin glistening white strand. It is anesthetized with an injection in the immediate vicinity of its inferior portion. This provides anesthesia to the ipsilateral lower lip and chin.

In addition to the above branches, there are other branches of the trigeminal nerve that are also amenable to regional nerve blocks. These include the buccal, auriculotemporal, anterior ethmoidal (external nasal branches), and zygomaticotemporal nerves. A block of the greater auricular nerve off the cervical plexus provides anesthesia to the posterior auricle and angle of the mandible.

Nerve blocks can be a valuable tool for nonfacial locations as well. In particular, digital nerve blocks are very useful for procedures involving the digit or nail unit. The cutaneous sensation of a digit is supplied by two nerves coursing down each of the lateral aspects of the digit. For a block, the needle is inserted perpendicularly into the lateral aspect of each side of the digit and advanced until bone is reached. At this position, a small volume of anesthetic is administered. The delivery of a large volume (greater than 1 mL) of anesthetic in the digits can result in tamponade of the digital circulation with subsequent necrosis. This tamponade effect now appears to be more critical factor in cases of digital necrosis than the use of epinephrine.

Electrosurgery and Electrocautery

(See Chapter 246)

Suture Materials

The proper selection of suture material for any dermatologic procedure is vital to its successful outcome. There are several intrinsic characteristics of each suture material, which will influence this selection process (Table 242-2). Sutures are produced in both absorbable and nonabsorbable forms. An absorbable suture is classified as one, which loses half of its tensile strength within 2 months. Absorbable sutures are primarily used for the approximation of dermal and subcutaneous tissue. As wounds have achieved less than 10% of their final tensile strength at 2 weeks, these sutures maintain the structural support of wounds during the initial healing phase. The time that a suture maintains its tensile strength is dependent on the material of which it is composed.

Nonabsorbable sutures are predominantly used for external suturing with subsequent removal in the days after the procedure. In this instance, these sutures are used more for fine epidermal approximation than structural support. On occasion, nonabsorbable sutures are also used for the placement of subcutaneous tissue, muscle, and fascia, when a more permanent placement of the tissue is desired.

Sutures are produced as monofilaments (single-strand) or multifilaments (multiple-braided strands). Monofilaments offer the advantage of increased ease of pull-through tissue, less risk of infection, and decreased tissue reactivity. The disadvantage of monofilaments is the increase in memory, or the tendency for a material to revert to its original shape. This memory results in decreased ease of handling of the suture and decreased knot security for monofilaments. Multifilaments, or braided sutures, offer ease of handling and increased knot security. However, the strands of a multifilament have the capability to trap fluid and bacteria resulting in an increased risk of infection with their use.

In general, the smallest suture, which provides adequate tensile strength for a defect, should be utilized. Suture size is measured in multiple of zeros based upon the diameter of the suture material. The higher the number preceding the zero, the smaller the diameter of the suture. Typically, 5-0 and 6-0 sutures are used on regions of low tension, such as the face, eyelids, and ears. Areas of higher tension, such as the trunk, extremities, and scalp, require 3-0 and 4-0 sutures. Areas of intermediate tension, such as the neck, may be closed with either 4-0 or 5-0 sutures. There are a wide range of needles whose nomenclature varies with manufacturer. In general, most skin surgery procedures are best performed with plastic surgery needles.

Suturing Technique

Meticulous suturing technique is fundamental to obtaining excellent aesthetic and functional results. Properly placed sutures allow for approximation of wound edges, wound-edge eversion, minimization and redistribution of tension, elimination of dead space, maintenance or restoration of natural anatomic contours, and avoiding permanent suture marks on the skin surface. The suturing technique selected for a specific wound closure depends on the anatomic location, tension, thickness of the wound edges, and goals of the surgeon.

Interrupted Sutures

The simple interrupted suture is the most basic and versatile suture used by dermatologic surgeons. Absorbable, buried interrupted sutures are used as part of the layered wound closure. These sutures provide support for the wound until tensile strength has increased sufficiently to prevent wound dehiscence and reduce tension on the wound edges. To achieve good eversion of the wound edges, these are best placed in the deep dermis and subcutis in a heart-shaped configuration (Fig. 242-8).9 Wounds in which one skin edge appears higher than the other can be appropriately aligned by taking a larger bite from the lower edge and a smaller, more superficial bite from the higher edge.

Epidermal simple interrupted sutures, used to obtain optimal alignment of the epidermal edges of the wound, are more time-consuming to place and remove than continuous running sutures. In settings where wound healing may be impaired because of the patient's underlying medical condition or in areas of high tension, interrupted sutures may be preferred. This type of suture usually provides greater tensile strength and less potential to cause edema, induration, and impaired microcirculation than running sutures. In addition, in areas of high tension, the risk of wound dehiscence can be assessed by removing alternate sutures. If it seems that dehiscence is likely, the remaining sutures may be left in place for 3–4 additional days.

The vertical mattress suture provides wound-edge eversion, reduces dead space, and minimizes tension across the wound (Fig. 242-9). It achieves the same effect as a buried dermal suture and an epidermal suture. Because this suture requires four entry points in the skin, significant crosshatching can be expected if the suture is not removed within 5–7 days. This suture by nature is a tightly placed suture and can be difficult to remove because of its tendency to become embedded in the skin.

The horizontal mattress suture has been used to reduce tension across wound closures that are under significant tension (Fig. 242-10). This technique also creates wound eversion. This suture can be placed as an initial tension-reducing or -holding suture and to bring the wound edges closer together, so that subcutaneous sutures can be placed to distribute tension and close the wound. At this point, if the tension has been adequately distributed, the horizontal mattress suture may be removed. If tension across the wound persists, the horizontal mattress suture may be left in place for a few days while early wound healing proceeds and removed before suture tracks have had a chance to form. The main disadvantage of this suture is the possibility of wound-edge necrosis as this suture can easily strangulate the dermal plexus between its limbs. This problem is minimized by taking large bites with the needle to encompass large amounts of tissue, by using bolsters, by tying the suture only as tight as necessary to accomplish the task of bringing the wound edges together, and by removing the suture as soon as possible. Before contemplating the use of a horizontal mattress suture for tension reduction, the surgeon should consider other means of reducing tension across the wound, including appropriate use of undermining and closure orientation, flaps from areas of tissue excess, preoperative or intraoperative tissue expanders, serial excisions, and subcutaneous sutures.

The half-buried horizontal mattress suture is primarily indicated for the positioning of various corners and tips including flap tips, M-plasty tips, and V-Y closure tips. It can also align the edges of tangential flaps and flaps with ischemic wound edges. The buried limb of this suture is placed in the potentially ischemic area in order to minimize interference with the dermal vascular plexus. A superficial simple interrupted suture through a flap tip may also work without resulting in increased risk of flap tip necrosis.

Running Sutures

The simple running suture can be used in situations where the wound edges are of equal thickness without tension, closely approximated, and with an absence of subcutaneous dead space. This suture is most useful for wounds that have already been closed by buried sutures, for the attachment of full-thickness or split-thickness skin grafts, and in areas of thin skin such as the eyelids, ears, neck, and scrotum. By eliminating all but two knots, there is less suture material resting against the skin, resulting in the development of fewer scars from suture marks. However, fine adjustments along the suture line are difficult to make and the suture has a tendency to pucker when very lax and thin skin, such as eyelid skin, is being sutured. In thin skin, the knots at each end may be tied over small bolsters to prevent them from cutting into the tissue.

The running locking suture is a variant of the simple running suture in which, after the placement of each loop, the needle is passed through the previous loop prior to starting the next loop. It is intended for the closure of well-vascularized wounds under a moderate amount of tension. The wound edges should be stiff and of equal thickness without a tendency for inversion. It is stronger than a simple running suture. However, if it is placed too tightly or if significant postoperative swelling develops, tissue strangulation with wound-edge necrosis may ensue.

The running subcuticular suture is a buried running suture that is usually not absorbable. It is ideal for the closure of wounds in areas such as the trunk and extremities where the suture must remain in place for more than 7 days. As the suture is buried, there are no suture marks and the suture may be left in place for several weeks, even months. When absorbable suture material is used, it may be left in place until it is absorbed. As this suture is capable of only modest wound-edge alignment, it should be reserved for wounds in which the tension has been eliminated with deep sutures and the wound edges, of approximately equal thickness, are closely approximated. The running subcuticular suture should be placed with a nonreactive monofilament suture such as polypropylene to facilitate suture removal and prevent suture breakage within the wound. Some surgeons use a permanent suture left in place indefinitely, as this can reduce scar stretching. If nonabsorbable sutures are selected clear, nonreactive suture material should be used.

Suture Removal

Timing of suture removal must balance two factors: (1) leaving the sutures in place long enough to allow wound healing and prevent dehiscence and (2) removal before the development of suture track marks along the scar line. These suture track marks occur because reepithelialization occurs around the suture. In general, the less the blood supply to an area and the greater the tension across a wound, the longer the sutures should be left in place. On the face and ears, most skin sutures should be removed within 5–7 days. Eyelid sutures can be removed in 3–5 days. Neck sutures should be removed in 7 days and scalp sutures in 7–10 days. On the trunk and extremities, risk of wound dehiscence takes precedence over suture marks. Sutures on the trunk and upper extremities should be left in place for 7–14 days. Lower extremities may require up to 21 days of suture support, though, with proper deep suture placement, epidermal sutures can generally be removed in 7–10 days.

Absorbable sutures are not removed, but some patients develop suture reactions, consisting of sterile suture abscesses and suture extrusion through the wound. If this happens, the suture should be picked up carefully with small forceps and cut out of the wound. Any purulent material should also be drained.

Staple Closure

Staple closure of wounds is an alternative to suture closure. The staples have the advantage of very quick placement, minimal tissue reaction, and very strong wound closure. Staples are most often used with long wounds, especially on the scalp, where the suture line is hidden by scalp hair. Potentially contaminated wounds that are closed with staples appear to be more resistant to infection than wounds closed with sutures. Staples provide efficient wound closure; but when exact wound-edge alignment is required, sutures should be used. Staples are easily removed with a staple remover.

Most wounds can be cleaned appropriately with tap water and mild soaps. A diluted acetic acid solution can be helpful to prevent Pseudomonas infection in sites predisposed to this. Small amounts of hydrogen peroxide can help debride wounds that have developed significant crusting and exudate. However, in large amounts, hydrogen peroxide can be toxic to the development of new cells and thus inhibit wound healing. Most wounds are also best dressed with petrolatum and a nonadherent dressing. Petrolatum is relatively inert, nontoxic, nonsensitizing, and nonirritating. Although not common knowledge for the layperson, it has been well proven for years that covered or occluded wounds reepithelialize and heal faster than dry wounds.10 There is a significant risk for allergic contact dermatitis with topical antibiotics, and they have not been shown to be superior to petroleum jelly in preventing wound infections. For wounds with significant drainage, dressings such as gauze, foam dressings, or alginates provide absorption.