Surgical incision Professor Magdy Amin RIAD Professor of Otolaryngology. Ain shames University Senior Lecturer in Otolaryngology University of Dundee

6 major aesthetic units The face consists of 6 major aesthetic units comprised of: forehead, eye/eyebrow, nose, lips, chin, and cheek .

6 major aesthetic units Correct orientation of planned incisions next to these mobile functional and aesthetic facial structures is important to avoid distortion when closing wounds.

anatomical subunits These aesthetic units can be subdivided into additional anatomical subunits. For example, the nose can be divided into nasal tip, dorsum, columella, soft-tissue triangles, sidewalls, and nasal alar regions.

anatomical subunits Optimally, perform an incision or an excision within or parallel to the relaxed skin-tension lines (RSTLs) of the face

skin-tension lines RSTLs can be defined as the skin-tension lines that are oriented along the furrows formed when skin is relaxed. The resting tone and contractile forces of underlying facial musculature perpendicular to skin-tension lines contribute to RSTLs.

skin-tension lines Unlike wrinkle lines, RSTLs are not clearly visible on the skin. While pinching the skin, however, RSTLs can be observed from the furrows and ridges thus revealed.

The closer an incision comes to lying within an RSTL, the better the ultimate cosmetic appearance of the scar. If possible, avoid making incisions perpendicular to RSTLs because the greatest amount of lax skin lies perpendicular to RSTLs.

In addition to planning incisions along RSTLs or at the border of facial aesthetic units (ie, forehead, eye/eyebrow, nose, lips, chin, cheek), adherence to techniques of tensionless wound closure, wound edge eversion, and atraumatic handling of tissues optimizes scar appearance.

When a wound cannot be closed primarily Reconstructive options include healing by secondary intention, local or regional flaps, or skin grafts. When removal of the majority of a facial aesthetic unit is anticipated, excision of the remaining aesthetic skin unit can be considered before reconstructive coverage.

When a wound cannot be closed primarily This can help minimize scars by having them lie along the aesthetic unit boundaries. When a defect encompasses more than 1 aesthetic unit, each unit can be reconstructed as a separate entity.

Cutaneous vascular regions of the face When considering incisions for local flap coverage, take advantage of the cutaneous vascular regions of the face to optimize viability of the flap and insure primary healing. These vascular regions are defined by the 4 main paired arteries of the face, which provide the major blood supply to facial skin.

Major arteries to the facial skin (1) the supratrochlear artery, which contributes to the central forehead and palpebral region; (2) the supraorbital artery, which perfuses the medial forehead region; (3) the temporal artery, which branches into superficial temporal and transverse facial arteries supplying the temporal forehead, lateral cheek, and periauricular regions; and (4) the facial artery, which leads into the superior and inferior labial, angular, and palpebral arteries, thereby perfusing the central and lower mid face.

appropriate surgical incision When incisions are made within a hair-bearing surface, place the blade parallel to hair follicles to prevent their transection and damage.

Fusiform skin defect When a fusiform skin incision is planned, the long axis of the fusiform excision should follow RSTLs .

Fusiform skin defect To minimize a dog-ear deformity during closure, the angle of the fusiform apex should be less than 30°, and the lengths of each side of the incision should be made equal to each other.

Fusiform skin defect When such an angle cannot be made, an M-plasty can be made at the apex to minimize a dog-ear deformity

Evaluate the planned skin incision in its relationship to the facial subunits in attempting, as much as possible, to achieve symmetry with the contralateral normal face. The contralateral normal facial region can serve as a helpful visual template for comparison.

When obtaining hemostasis close to peripheral nerves, careful bipolar cauterization or suture ligature is recommended. Evaluation of wound type (ie, laceration, tissue loss) and wound depth (ie, subcutaneous, facial musculature, cartilage, bone) is critical in planning the best closure method. Determine extent of tissue loss, viability of skin edges, and angulation of wound edges

Devitalized tissue margins can be sharply debrided. In addition, perform careful undermining of surrounding tissues to minimize tension on the incision closure. If possible, perform primary closure under minimal, or ideally, no tension. Layered closure of the wound helps decrease tension at the skin level.

Absorbable buried suture can be used to approximate deeper layers to avoid excessive tension on the skin. Nonabsorbable or absorbable suture can be used on the skin surface with gentle eversion of skin edges. Generally, use 5-0 to 3-0 absorbable sutures for deeper layers and 6-0 to 5-0 sutures (permanent or absorbable) for skin

Differential undermining of wound edges in the subcutaneous plane may be needed to avoid distortion of nearby structures. Accomplish this by creating a subcutaneous plane on one side of the wound. Perform this technique only to advance the undermined side of the wound so that the nonundermined side will not be as mobile, thereby preventing distortion of nearby structures.

A "trapdoor" deformity resulting from a beveled wound edge can be prevented by conservatively excising the excess skin tangentially to its wound surface to create a more vertical skin edge. Also excise the opposite skin edge to match it. Perform undermining within the same depth of plane on each side of the wound to allow for correct reapproximation of the corresponding tissue layers

secondary intention Healing by secondary intention is a treatment option for superficial wounds. This process occurs when the wound is left open, allowing it to spontaneously contract and epithelialize on its own. Healing by secondary intention is inappropriate for complex defects where multiple tissue layers are missing and structural support is needed.

secondary intention Cosmetic results of a defect healing by secondary intention depend upon the facial region involved. Concave facial surfaces (eg, medial canthus, temple, nasofacial crease, nasomalar grooves, auricle) heal with good results.

secondary intention Cosmetically, convex facial surfaces located on the nose, cheek, chin, lips, and helix do not heal as well by secondary intention. At these regions, depressed and hypertrophic scars frequently occur.

Disadvantages of healing by secondary intention include (1) a longer period of healing; (2) often, increased hypopigmentation of reepithelialized scars; and (3) more contraction of surrounding soft tissue, which causes drifting of neighboring structures.

Factors contributing to poor healing often result in scarring. The primary goals after closing an incision are to (1) maintain an optimal wound-healing environment, (2) minimize infection, (3) debride devitalized tissues, (4) maintain vital structural support, (5) maintain tensionless wound closure, and (6) prevent hypertrophic scarring.

Optimal wound environment Debride necrotic tissue to decrease infection risk. Maintain fresh wound edges along the incision to encourage epithelialization.

Optimal wound environment Irrigate copiously to clean the wound and remove foreign bodies. Irrigation can be performed with normal saline or commercial wound cleanser. Irrigation is the single most effective technique to accomplish wound cleaning. Obtain hemostasis and place drains to prevent any excess fluid collection (eg, hematoma, seroma) and to avoid infection. Absorb excess wound exudate to prevent maceration of surrounding skin.

Optimal wound environment Divert any salivary drainage away from the wound to minimize bacterial contamination. Maintain a moist wound environment with topical ointments or hydrogels to encourage epithelialization. Protect the wound from trauma.

Optimal wound environment In wounds with potential for infection, institute appropriate oral and topical antibiotics for 7-10 days. Abrasions and wounds can be covered with hydrogel sheeting for exudative wounds or clear transparent dressing (ie, Tegaderm, OpSite) for nonexudative wounds. To avoid cellular damage, do not repetitively apply skin cleansers (eg, hydrogen peroxide, Betadine, Hibiclens) in a wound

Wound follow up After 5-7 days, remove facial skin sutures and apply Steri-Strips for 1 week to decrease tension to the incision. If an incision appears to be developing into a hypertrophic scar, consideration can be given to using injectable triamcinolone acetate, Cordran tape, or topical silicone-gel sheeting. A sign that excessive scar formation could be developing is a persistently nontender, erythematous, raised-skin surface, which is present after several weeks.

Scar revision For at least 6 months, do not perform aggressive scar revision to allow for normal scar maturity. When scar segments do not follow RSTLs, surgeons may choose to revise unsatisfactory scars after 6 months with multiple Z-plasty, geometric closure, or W-plasty.

Scar revision Earlier scar revision intervention is indicated if facial function will be compromised or distorted from contraction (ie, compromising eye closure, mouth movement). Inform patients that it takes at least 6 months for scar maturation. Adjunctive camouflage makeup can be a helpful conservative measure to reduce scar