Chapter 7: Dermatologic Procedures

Introduction

A skin biopsy is done to gather more information than is available from the patient's history and physical examination. This information can be used to establish or confirm a diagnosis. Often clinicians hesitate to perform a biopsy. There may be concerns about the cosmetic impact on the patient, the trauma associated with the procedure, or the technical aspects involved. Some disease processes are prone to sampling error and may require multiple skin biopsies for diagnosis. This is classically the case with cutaneous T-cell lymphoma or diseases with lesions of various stages or morphology.

Types of Biopsy Techniques

It is important to select the appropriate site, lesion, and technique for a biopsy. This often means focusing on the location of the suspected pathologic process, for example, the epidermis, the dermal epidermal junction, deeper dermal structures, or subcutaneous dermal fat or muscle. The likely location of the pathology will determine if a shave, punch, or an excisional biopsy is most appropriate (Table 7-1).^1,2 A biopsy should not be done on lesions that are excoriated or eroded.

Table 7-1.Lesion, site, and biopsy selection for skin disorders.

Table 7-1. Lesion, site, and biopsy selection for skin disorders.

Disorder

Procedures for Biopsy

Lesion or Site Selection

Dermatoses (rash) in epidermis or superficial dermis (lesions are not indurated, sclerotic, or deep)

Dermatoses in deep dermis or fat (lesions are indurated, sclerotic, or deep)

Punch or shave

Punch, incision, or excision

Select lesions that are characteristic or typical of the rash. Avoid old resolving lesions and excoriated lesions. If possible, avoid cosmetically sensitive areas, such as the central face

Vesiculobullous diseases for routine histology

Punch or shave

Biopsy new lesions 2-7 days old with bullae intact. Include the edge of blister and perilesional normal skin

Vesiculobullous diseases for immunofluorescence studies

Punch or shave

For suspected pemphigoid and pemphigus biopsy perilesional skin. For suspected dermatitis herpetiformis biopsy normal adjacent skin

Ulcers

Punch or incision

Biopsy edge of ulcer, not the necrotic center

Tumors that are not suspected to be of melanocytic origin

Deep shave, punch, incision, or excision

Biopsy the thickest or elevated area

Tumors that are suspected to be of melanocytic origin (eg, lentigo, nevus, atypical nevus, or melanoma)

Deep shave, saucerization biopsy, excision, or punch biopsy (for small lesions)^3,4

Remove entire lesion for biopsy

Shave biopsy: This is the most commonly used biopsy technique. It has the advantage of being less time consuming, yielding a good cosmetic result, and having a limited downtime for the patient. It is typically limited to processes occurring to the depth of the mid dermis. A saucerization biopsy is similar to a shave biopsy, but usually extends to the mid to lower dermis.^3,5 If done too deeply, in certain locations the biopsy site may heal slowly (eg, on the lower leg) or leave a scar (eg, on the nose).
Punch biopsy: This has the advantage of providing a sample of full thickness skin, rapid healing, and uniform control. It is limited by the diameter of the punch tool, and may not be adequate for processes in the subcutaneous tissue.
Excision and incision/wedge biopsy: These are more advanced procedures that are done using a sterile technique. Advantages include an adequate sample down to the subcutaneous tissues. Margins can also be controlled and adjusted as needed. Limitations include the increased duration of the procedure and a longer healing time with a greater potential for scarring.

Equipment for Procedures

The next section contains a list of standard equipment that is essential for most dermatologic procedures. For each type of procedure additions to the standard tray are listed within the associated section. When surgical trays are being prepared, it is important to decide if the procedure will be clean or sterile. Shave biopsy and punch biopsy are performed with a clean technique. Deeper procedures such as excisions require a full sterile technique including a sterile tray, gloves, and disposables (eg, gauze sponges).

Dermatology Standard Equipment Tray

Seventy percent isopropyl alcohol pads/swabs, surgical marking pen, cotton-tipped applicators, and 4" × 4" gauze sponges.
Sterile pack containing no. 3 scalpel handle, iris scissors, and Adson or Bishop forceps with small teeth.
Dressing including bandage and sterile petroleum jelly.
Pathology materials including a biopsy bottle (with 10% formalin for routine biopsies) labeled with the patient's name, identification number, birthdate, and the biopsy site. A pathology requisition slip and a biohazard bag are also needed.

Electrosurgery Devices

Electrodessication and electrocautery are the most commonly used elctrosurgery procedures in dermatology. Electrodessication is primarily used to destroy tissue in superficial benign or malignant tumors and to control bleeding. It is performed using a device with a single electrode tip (monoterminal) and high voltage and low amperage (Figure 7-1).⁶ The electrical spark generated by this device causes desiccation (dehydration) of the treated tissue. Electrodesiccation should not be used in any patient with a pacemaker or implantable cardiac defibrillator as it can interfere with their function.

Figure 7-1.

Electrocautery (left) is done with 2 electrode tips (biterminal) as in this battery-operated device. Electrodessication (right) is done with a single electrode tip (monoterminal).

Electrocautery is performed using a device with 2 electrodes (biterminal) and low voltage and high amperage (Figure 7-1).⁶ The heat generated by this device destroys deeper tumors and controls bleeding by coagulation. Battery-operated disposable electrocautery devices are available. Electrocautery can be used in patients with implantable cardiac devices.

Patient Preparation

Care must be taken to properly inform the patient of the risks of any dermatologic procedure. Setting clear expectations is critical. The patient may have unrealistic expectations for scarring (or the expected lack thereof), or the anticipated duration of healing. This leads to frustration on the part of the patient and may lead to a negative impression of an otherwise normal outcome. Discussing these aspects clearly with the patient prior to the biopsy is critical, as is a review of postprocedure care. Patients do not need to stop aspirin or prescription anticoagulants for the skin procedures covered in this chapter.

After the risks, benefits, and alternatives of the procedure have been discussed, informed consent should be obtained and documented in the chart. Once the equipment is prepared, attention should turn to preparing the patient. Patient care should focus on limiting the physical and emotional trauma that may be associated with the procedure. The patient should be in a reclined, comfortable position that he or she can maintain during the entire procedure.

Anesthesia

Injectable local anesthetics are commonly used for skin biopsies. One percent lidocaine with epinephrine added at 1:100,000 is generally standard for most dermatologic procedures. Epinephrine decreases bleeding and increases the duration dermatologic procedures. Onset of anesthesia after injection is very rapid with lidocaine. Epinephrine decreases bleeding and increases the duration of the anesthetic effect. Vasoconstriction from epinephrine may take 5 to 15 minutes for full onset. In sites with a high vascular network, like the scalp, waiting for several minutes postinjection will allow for vasoconstriction onset and greatly reduce bleeding during the procedure.

The maximum dose of lidocaine varies with the weight of the patient. The package insert recommendations for adult patients are 4.5 mg/kg (not to exceed 300 mg) for plain lidocaine and 7 mg/kg (not to exceed 500 mg) for lidocaine with epinephrine. Some patients metabolize lidocaine at a much higher rate and will require a larger dose. Other amide anesthetics vary in timing of onset and duration. A syringe is selected to match the anticipated volume of lidocaine, typically 1 to 3 cm³. Needle sizes of 26 or 30 gauge are preferred for patient comfort, but require increased pressure on the plunger and a slower rate of injection. Multiple syringes may be more appropriate for a large site as the needle will dull with repeated injections.

Lidocaine toxicity may initially present with tinnitus, lightheadedness, circumoral numbness, diplopia, or a metallic taste in the mouth. Nystagmus, slurred speech, localized muscle twitching, or fine tremors may occur with more profound toxicity. Epinephrine can lead to tachycardia and a feeling of uneasiness.

There are several things that can be done to minimize the pain and stinging associated with anesthetic injection:⁵

8.4% sodium bicarbonate can be added to the anesthetic at 10:1 ratio to lower the pH⁵
The use of a 30-gauge needle
Slowing the rate of injection to reduce injection pressure
Icing or rubbing the skin
Distraction (having the patient grasp or squeeze an object)

Topical anesthetics have a limited role in skin biopsy procedures due to the limited depth of penetration and the duration of application required to get an adequate effect. Generally they do not penetrate past the dermal epidermal junction. For younger or more apprehensive patients, a topical anesthetic can be applied to the site prior to injectable anesthesia for procedures extending into the dermis. Options include EMLA (lidocaine 2.5% and prilocaine 2.5%) cream or topical lidocaine. Absorption is slow and takes upward of 20 to 30 minutes for onset and 1 hour for maximum effect. The topical anesthesia must be applied to a sufficient thickness with the recommended number of grams as per the package insert and covered with an occlusive dressing. Peak anesthesia is achieved only after 1 hour or longer. If the need for anesthesia is anticipated, the anesthetic could be applied at home 1 hour before the procedure.

SHAVE BIOPSY PROCEDURES

Shave Biopsy

A shave technique is appropriate for removal of benign superficial lesions and the biopsy of lesions that extend into the mid to lower dermis. Lesions appropriate for a shave biopsy include the following:

Dermatoses
Seborrheic keratoses and skin tags
Nevi (when melanoma is not a concern)
Suspected squamous and basal cell carcinomas
A controlled deep dermal shave biopsy (saucerization biopsy) can be appropriate for a lesion considered for melanoma if adequate depth is obtained. However, consider a punch biopsy for smaller lesions or an excisional biopsy for larger lesions.⁴

In addition to the standard tray, the following items are added:

Occupational Safety and Health Administration (OSHA)–approved safety blade (eg, DermaBlade or a no. 15 blade on a scalpel handle)
Twenty percent aluminum chloride solution (eg, Drysol) for hemostasis with cotton-tipped applicators

The steps for a shave biopsy are presented in Table 7-2.^3,5

Table 7-2.Shave biopsy procedure.

Table 7-2. Shave biopsy procedure.

Clean the biopsy site with 70% isopropyl alcohol pads
Mark the borders of the lesion with a surgical making pen
Inject 1% lidocaine with epinephrine 1-100,000 subcutaneously at the margin of the biopsy site, followed by intradermal infiltration creating a slightly elevated wheal above the plane of the skin
For a superficial shave biopsy with a safety blade or scalpel, enter the skin parallel or at an angle of approximately 10° to the plane of the skin and at a steeper angle for deeper shave biopsies. For a saucerization biopsy, enter the skin at an angle of approximately 45°
Use a smooth, short, back and forth motion of the blade to allow the cutting edge to slide through the tissue (Figure 7-2)
Diminish the angle to maintain depth within the dermal plane
If a safety blade is being used, control the depth of the biopsy by adjusting the curvature of the blade
Use pressure with the tip of a cotton applicator to minimize tissue movement during the shave biopsy
Exit the biopsy with a more acute angle
Place the sample in the previously labeled specimen container
Wipe the biopsy site with a gauze pad and press a cotton-tipped applicator soaked in aluminum chloride on the site to control bleeding. Use electrodessication if the biopsy site continues to bleed. Remember to ask patients about implanted cardiac devices before using electrodessication. If the patient has a cardiac device, use electrocautery if needed
After hemostasis is obtained, cover the biopsy site with sterile petroleum jelly and a bandage with adhesion on all sides sufficient to cover the biopsy site
Instruct the patient to remove the bandage in 24 h and wash the area with soap and water and apply petroleum jelly for 14 days or until the wound is healed

Figure 7-2.

Scalpel blade held parallel to plane of the skin cutting though the dermis below the nevus.

Video demonstrations of shave biopsy procedures on pig's feet and in a clinical setting can be found at www.LangeClinicalDermatology.com.

Punch Biopsy

A punch biopsy can be used as a diagnostic tool for lesions or dermatoses that extend into the deeper dermis or for removal of small- to medium-sized lesions such as compound/dermal nevi. Punch biopsy tools are typically available in increments of 1 mm and range in size from 2 to 10 mm in diameter. The most commonly used sizes for diagnostic biopsies are 3 to 4 mm.

In addition to the standard tray, the following items are needed for a punch biopsy:

A punch tool of the appropriate size
Twenty percent aluminum chloride solution (eg, Drysol) for hemostasis with cotton-tipped applicators
A needle holder
Suture, typically 4.0 or 5.0 polypropylene or nylon on a P-3 needle

The steps for a punch biopsy are presented in Table 7-3.^3,5

Table 7-3.Punch biopsy procedure.

Table 7-3. Punch biopsy procedure.

Cleanse, mark, and inject the biopsy site with lidocaine as in the shave biopsy procedure in Table 7-2
Stretch the skin with the nondominant hand perpendicular to the relaxed tension lines (eg, wrinkle or Langer's lines) of the skin so that an oval rather than round defect will be created
Place the punch tool vertically over the lesion and twist and push down with increasing pressure (Figure 7-3A)
When the punch tool reaches the depth of the subcutaneous fat, there will be a decrease in tissue tension and the surrounding tissue will reach the level of the punch bezel
Remove the core of tissue by very gently grasping the edge with forceps, taking care to not squeeze or crush the tissue. If the tissue is still attached to the skin, use scissors to snip the base of the specimen (Figure 7-3B)
Place the biopsy specimen directly into the appropriate specimen bottle
Control bleeding by wiping the biopsy site with a gauze pad and pressing a cotton-tipped applicator soaked in aluminum chloride over the site. Electrocautery is generally not necessary
Small ≤4 mm punch biopsies can be left open to heal by secondary intention³
If the biopsy is >4 mm, the site can be closed with interrupted sutures on either side of the center of the biopsy defect
Use 4.0 polypropylene or 4.0 nylon on a P-3 needle for the trunk and extremities and 5.0 sutures for the face. The number of sutures is determined by the diameter of the defect. Alternatively, a figure of 8 suture technique can be used
Place sterile petroleum jelly over the site and apply a bandage
Instruct the patient to come back for suture removal in 7-10 days for the face and in 14 days for the trunk and extremities

Figure 7-3.

Punch biopsy. A: Punch biopsy tool held perpendicular to the skin and pressed halfway into the dermis. B: Tissue sample is gently grasped with forceps and base of the specimen is cut with iris scissors while assistant controls bleeding with cotton-tipped applicator.

Video demonstrations of punch biopsy procedures on pig's feet and in a clinical setting can be found at www.LangeClinicalDermatology.com.

EXCISION

Excisions are used for biopsy of lesions or inflammatory processes that are in the deep dermis or subcuticular fat. They also can be used for removal of large benign lesions or malignant tumors such as basal or squamous cell carcinomas.

In addition to the standard tray, the following items are needed for an excision:

Sterile drapes, gloves, and bandages
Povidone–iodine solution
A number 15-scalpel blade and tissue scissors
A needle holder
3-0 or 4-0 absorbable sutures (eg, Vicryl, Dexon) and nonabsorbable 4.0 or 5.0 sutures (eg, Prolene, Ethilon) on a P-3 needle. Alternative suture and needle sizes may be needed depending on location and degree of wound tension (Table 7-4)

Table 7-4.^*Selection of suture size and timing of suture removal.

Table 7-4. Selection of suture size and timing of suture removal.

Location

Deep Absorbable Sutures (eg, Vicryl, Dexon)

Nonabsorbable Sutures for Closure of Epidermis (eg, Prolene, Nylon)

Timing of Suture Removal in Days*

Face and neck

5.0-6.0

Face—5-7

Neck—7-10

Back, scalp

3.0-4.0

14-21

Trunk and extremities

4.0

10-14

Longer duration decreases risk of dehiscence, but may increase scarring.

The steps for an excision are presented in Table 7-5.⁷

Table 7-5.Excision procedure.

Table 7-5. Excision procedure.

Mark the planned surgical margins using a surgical marking pen. The width of the fusiform excision should include 2 mm margins for benign lesions and 4-5 mm for basal or squamous cell carcinomas. The length of the excision should be 3 times greater than the width and the angle at the corner of the excision should be 30° or less. The long axis of the excision should be along the relaxed skin tension lines or at a cosmetic junction (Figure 7-4)
Cleanse the skin with 70% isopropyl alcohol pads
Inject 1% lidocaine with epinephrine 1:100,000 subcutaneously around the margin of the planned excision, carefully placing the needle into the edge of area that has already been anesthetized. Then inject the lidocaine intradermally until there is a slight swelling of the tissue
Cleanse the skin with povidone–iodine solution and place sterile drapes around the surgical site
To begin the excision insert the tip of the scalpel blade at the distal apex of the incision perpendicular and at 90° angle to the plane of the skin
Lower the blade to a 45° angle and use the belly of the blade to cut the tissue rather than the tip that would quickly dull
Continue with increased pressure and a smooth steady motion to the depth of the subcutaneous fat. At that point the tissue relaxes around the excision. It may take 2 passes to extend through the dermis depending on the site
As the proximal apex of the excision is reached, increase the angle of the blade back to 90° to generate a clean excision with the tip of the blade
Repeat the previous 4 steps on the other side of the excision
Lift the skin specimen with forceps and separate the tissue specimen from the base of the excision at the level of the subcutaneous fat with the scalpel blade held parallel to the skin or with iris scissors. The thickness of the specimen should be uniform
Place the sample in the previously labeled specimen container
Use electrocautery or electrodesiccation to stop bleeding, taking care to limit thermal damage to the epidermis
Narrowly undermine the skin at the level of the subcutaneous fat with rounded tip Mayo or Metzenbaum scissors
Use absorbable suture in an interrupted pattern to approximate the deep dermis. Place each suture deep to superficial on one wound edge and superficial to deep on the other wound edge. This buries the knot deep in the wound. This can proceed from either the center to each apex for wounds of low tension or the apex to the center for high-tension wounds
Close the epidermis with either interrupted sutures or a running suture. Wound margins should be carefully approximated without tension to achieve a satisfactory cosmetic result
Place sterile petroleum jelly over the excision site and cover with an adhesive bandage

Figure 7-4.

Excision. The margins of the excision are marked to create at 3:1 length to width.

Video demonstrations of suturing techniques and excisions on pig's feet and in a clinical setting can be found at www.LangeClinicalDermatology.com.

DESTRUCTIVE TECHNIQUES

Cryotherapy

Cryotherapy is a common office procedure, and is the mainstay for the treatment of many benign and precancerous lesions. Liquid nitrogen, which has a boiling point of −196°C (−321°F), is the coldest and most commonly used cryogen. A 30 second spray of liquid nitrogen will result in tissue temperatures of −25°C to −50°C (−13°F to −58°F). Most benign lesions will be destroyed at a tissue temperature of −20°C to 30°C.⁸

The use of cryosurgical devices (eg, CRY-AC, CryoPro, FrigiSpray) with a spray tip and fingertip trigger is a safe and accurate way to use liquid nitrogen. Lesions commonly treated with cryotherapy include actinic keratoses, viral warts (human papillomavirus and molluscum contagiosum), seborrheic keratoses, and skin tags.

The patient should be informed that cryotherapy is painful during and sometimes for several minutes after the procedure. Erythema, bullae, and sometimes hemorrhagic bullae may develop. Hypopigmentation may be more prominent in individuals with darker skin types. Scarring can occur if the freezing extends into the dermis.

Procedure

Position the nozzle of the spray tip 1 to 1.5 cm from the lesion to be treated.
Spray the lesion until a 2 mm rim of frost develops around the lesion and then continue spraying for 5 to 30 seconds depending on the thickness, diameter, and location of the lesions (Figure 7-5). For larger lesions this can be done in spiral or paintbrush pattern. Approximate freeze times vary.
- Actinic keratosis: 5 to 20 second freeze cycle, depending on the location and size of the lesion⁹
- Seborrheic keratosis: 5 to 10 seconds for thin, flat lesions⁸
- Warts: 10 seconds. Plantar warts may require a second freeze cycle¹⁰
- Skin tags: 5 seconds⁸
Cover the eyes, nostrils, and exterior auditory canal with gauze or cotton if cryosurgery is done near those sites. Care should also be taken not to deeply freeze the skin near the digital nerves on the medial and lateral aspects of the fingers and toes.

Figure 7-5.

Cryotherapy. The tip of the cryosurgical unit is used 1 cm from an actinic keratosis creating a 2 mm freeze margin.

Video demonstrations of cryotherapy can be found at www.LangeClinicalDermatology.com.

Curettage and Electrodesiccation

Curettage and electrodesiccation is a commonly used procedure for the treatment of seborrheic keratosis, certain types of viral warts, pyogenic granulomas, and superficial basal cell carcinomas. In the hands of an experienced clinician, it also can be used for some small nodular basal cell carcinomas.¹¹ Electrodesiccation without cautery can be used on small skin tags and cherry angiomas. Electrodesiccation should not be used on any patient with an implantable cardiac device. If needed, a battery-operated, disposable heat cautery device could be used in these patients.

The patients should be informed of the risks of the procedure that include bleeding, infection, scars, and hyperpigmentation or hypopigmentation.

Equipment needed in addition to the standard tray is as follows:

Fox round or oval curette, sizes 3 to 5 mm are most commonly used.
Monoterminal electrodesiccation unit.

The steps for curettage and electrodesiccation are presented in Table 7-6.¹²

Table 7-6.Curettage and electrodesiccation procedure.

Table 7-6. Curettage and electrodesiccation procedure.

Cleanse and anesthetize the skin as for shave and punch biopsies
Let the alcohol dry completely before proceeding to prevent possible fire
Hold the curette in the dominant hand at a 45° angle and with firm pressure scrape the curette across the lesion with 1 or more smooth strokes. The nondominant hand can be used to stabilize the skin (Figure 7-6A and B)
Repeat the procedure by scraping perpendicular to the original direction of curettage until a firm base is obtained
Electrodesiccate the treated area at the lowest setting needed, taking care not to significantly increase the depth or width of the field
Use the side of the electrode rather than the tip in order to maintain greater control of the depth
Following electrodessication curette the tumor base again until a firm base is obtained. This will extend the wound margin by approximately 1 mm
For basal cell carcinomas repeat with 3 rounds of curettage followed by cautery
Place sterile petroleum jelly over the site and cover the site with an adhesive bandage
The site should be kept moist with petroleum jelly and covered until reepithelialized

Figure 7-6.

Curettage. A: Wheal produced by lidocaine in seborrheic keratosis. B: A curette is stroked across the keratosis with firm pressure.

Wound Care and Follow-Up

Wound care and follow-up are dictated by the type of procedure that was performed. Many patients have the false notion that air drying the wound will promote a more rapid healing response. In general, a clean wound will heal more rapidly and with less scarring if a good moisture barrier is maintained throughout the healing process. A firm pressure dressing is helpful for any full thickness procedure, and should be left in place for 24 to 48 hours.

Surgical Complications

Bleeding

Excessive bleeding during a procedure is disconcerting to both the clinician and the patient. Firm application of pressure for several minutes often controls bleeding. Identification of the bleeding vessel and compression while performing cautery is usually very effective. An assistant who can hold pressure and wick away blood that is obscuring the surgical field is critical in this process.

A second concern is postprocedure bleeding. As the vasoconstriction due to epinephrine wears off, bleeding may occur minutes or hours later. Even a small amount of blood may cause anxiety in a patient. The patient should be advised of this possibility and given clear instructions to apply firm constant pressure for a minimum of 15 minutes. If the bleeding does not stop after this process, medical care should be sought either with the clinician who performed the procedure or at an urgent care facility. The development of a hematoma under a closed wound if large and firm warrants evacuation, cautery, and resuturing of the wound.

Cardiac Devices

Part of patient screening should include questions regarding the presence of a pacemaker or implantable cardiac defibrillator. The use of monopolar electrodessication has a risk for triggering or damaging these devises. Electrocautery (heat cautery) and bipolar cautery should be used instead.

Infection

Whenever the skin barrier is breached, infection is possible and prophylactic antibiotics may be indicated. Infection is more likely in wounds that have been exposed to the environment, or in certain body areas such as distal extremities and areas near body orifices.

Depending on the wound location and the exposure risk, topical or oral antibiotics individually or in combination may be appropriate. Cephalexin is often prescribed for wounds of the lower extremity due to a higher risk of infection. When to use prophylaxis and what type of prophylaxis to use is often a topic of debate among experts and its specific application is beyond the scope of this text.

Some nonprescription topical antibiotic ointments (eg, bacitracin, neosporin) have a significant risk of allergic contact dermatitis. Whenever a wound becomes more inflamed with the use of a topical antibiotic, an allergic contact dermatitis must be considered. Mupirocin ointment is less likely to cause allergic contact dermatitis.

Wound Dehiscence

Separation of the wound can occur if the strength of the healing scar is not adequate at the time of suture removal. Excisions at sites with a poor vascular supply, such as the leg, will often require a significantly longer healing period of up to an additional week before suture removal. Infection can also lead to an increase in wound pressure and loss of wound integrity. Dehisced wounds can be resutured several days following a closure if the wound is cleaned and any risk for infection is addressed. The reclosed wound may require a drain if infection is present or anticipated. Resuturing should not be performed if an abscess is present. If the dehiscence occurs more than 24 hours after the excision, the reepithelialized tissue from the center of wound may need to be removed. A dehisced wound can also be left to heal with secondary intention, but this may result in a significant scar.

REFERENCES