You are in: eMedicine Specialties > Dermatology > SURGICAL Essentials of Tissue MovementArticle Last Updated: Mar 27, 2008AUTHOR AND EDITOR INFORMATIONSection 1 of 10
  Author: Keyvan Nouri, MD, Professor of Dermatology and Otolaryngology, Director of Mohs Micrographic Surgery, Dermatologic and Laser Surgery, Director of Surgical Training, Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine Keyvan Nouri is a member of the following medical societies: American Academy of Dermatology, American College of Mohs Micrographic Surgery and Cutaneous Oncology, American Medical Association, American Medical Student Association/Foundation, American Society for Dermatologic Surgery, American Society for Laser Medicine and Surgery, International Society for Dermatologic Surgery, Massachusetts Medical Society, and Phi Beta Kappa Coauthor(s): Christopher J Ballard, BS, MD, Resident, Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine; Voraphol Vejjabhinanta, MD, Postdoctoral Fellow in Mohs, Laser and Dermatologic Surgery, Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine; Clinical Instructor, Suphannahong Dermatology Institute, Bangkok, Thailand Editors: Désirée Ratner, MD, Director of Dermatologic Surgery, George Henry Fox Assistant Clinical Professor, Department of Dermatology, Columbia Presbyterian Medical Center, New York Presbyterian Hospital; David F Butler, MD, Professor of Dermatology, Texas A&M University College of Medicine; Director, Division of Dermatology, Scott and White Clinic; Director Dermatology Residency Training Program, Scott and White Clinic; Mary Farley, MD, Dermatologic Surgeon/Mohs Surgeon, Anne Arundel Surgery Center; Catherine Quirk, MD, Clinical Assistant Professor, Department of Dermatology, Brown University; Dirk M Elston, MD, Director, Department of Dermatology, Geisinger Medical Center Author and Editor Disclosure Synonyms and related keywords: aesthetic unit, cosmetic unit, graft, flap, free margins, guidelines for aesthetic surgical repair, partial closure, primary closure, primary defect, secondary defect, primary movement, secondary movement, reconstruction of surgical defects, second intention, skin reconstruction options, skin tension lines, surgical defect management INTRODUCTIONSection 2 of 10
  A solid understanding of anatomy and basic surgical principles is essential when undertaking the reconstruction of surgical defects. The primary foci of this article are options for managing surgical defects and guidelines for aesthetic surgical repair.
RECONSTRUCTION OPTIONSSection 3 of 10
Management options for surgical defects include the following: secondary intention healing, primary closure, partial closure, flaps, and grafts. When approaching the repair of surgical defects, assess the defect and its location. Depending on the size, the location, and the tissue laxity of the defect, one of these repair options may be preferable to the others. Secondary intention Secondary intention healing is usually ideal for wounds that are small and in a concave area, such as the curve of the nasal ala, the inner canthus, and the concave area of the auricle (eg, concha, scaphoid fossa). The nasal tip exemplifies a convex area. These areas heal poorly by secondary intention because the resulting concave scar will be on a convex surface. The use of secondary intention healing can also be considered if a wound is too large to reconstruct. If surveillance for tumor recurrence is important, secondary intention can serve as a useful option for defect management. Additionally, if the patient is not a candidate for reconstruction because of underlying medical conditions, secondary intention healing may be preferable to more extensive reconstructive options. Primary closure Primary closure is usually the best option for defect reconstruction. This method involves side-to-side closure of the wounds by using nonabsorbable superficial skin sutures with or without absorbable deep sutures. When a primary closure is planned, the length of the repair is generally 3 times the length of the defect (3:1 rule) to accommodate for dog ears (excess skin that protrudes when closing from side to side). Dog ears can also be removed after the defect has been closed primarily, thereby decreasing the length of the resulting scar. Partial closure With partial closure, sutures are used to only close a wound to a certain degree. Although the wound is not completely closed, the resultant wound is smaller and heals faster than the primary defect. This technique can transform a round defect into an ellipse. The wound will likely heal as a linear scar that can be placed in a cosmetically favorable location within related skin tension lines. The purse-string suture is another technique for partial closure. Grafts Grafts are another option for surgical defect management. Skin grafts can be divided into full-thickness grafts (includes the epidermis and full-thickness of the dermis), split-thickness skin grafts (includes the epidermis and partial-thickness of the dermis), and, more recently, artificial skin (eg, Graftskin [Apligraf]). For a skin graft to survive, an adequate underlying blood supply is essential; otherwise, graft failure may result. Full-thickness grafts should be used for reconstruction of facial defects in most instances; whereas, split-thickness grafts are beneficial for large wounds or at sites where tumor surveillance is a concern. Full-thickness skin grafts usually result in better cosmetic outcomes, whereas split-thickness skin grafts have better survival rates. When compared with secondary intention healing, full-thickness skin grafts minimize wound contraction at the site of the defect, which becomes important when dealing with wounds near free margins. The donor sites for full-thickness skin grafts should have an adequate reservoir of redundant skin that shares similar color, texture, thickness, vascularity, and sebaceous gland density to the recipient site. Flaps Flaps involve moving and borrowing adjacent skin to close the original defect. Depending on the direction of tissue movement, flaps that consist of skin and subcutaneous tissue may be divided into advancement, rotation, transposition, and subcutaneous island pedicle flaps. The advantage of flaps is that their final results tend to be cosmetically superior to skin grafts and secondary intention. The irregular scar pattern of flaps may be better camouflaged than the linear scar resulting from a primary closure. A greater risk for complications, such as pain, infection, necrosis, bleeding, and/or hematoma, occurs as a result of the additional tissue movement associated with flaps. Special consideration should be given to patients with underlying medical problems, such as peripheral vascular disease and diabetes. Poor wound healing also occurs in smokers and in patients taking systemic corticosteroids. When flaps or grafts are used, these factors can greatly increase the risk of reconstruction failure. Tissue movement depends on flap placement and pulling from surrounding structures. Primary movement is the result of tissue displacement at the site of the defect that leads to a secondary defect at the donor site. Secondary movement refers to the movement of tissue surrounding primary and secondary defects in response to the movement of the flap. Both of these movements can result in either displacement or tension on the surrounding tissue or free margins. Locations on the face that contain a reservoir of excess skin, such as the preauricular area, the glabella, the lateral portion of the temple, and the neck, may serve as useful sites for flaps. The reservoir skin from these areas can be used for closure of the adjacent defect. AESTHETIC UNITSSection 4 of 10
The face can be structured into functional divisions known as aesthetic units (otherwise known as regional, anatomical, or topographic units). Junction or contour lines define a specific region of the face contained within anatomical boundary lines. Within these margins, the tissue shares similar characteristics, such as hair density, skin tone, sebaceous distribution, vascular quality, and texture. Aesthetic units are of paramount importance when managing a defect. Scars are best hidden within contour lines, and these junctions may be preferable to relaxed skin tension lines for scar placement. Every attempt should be taken not to cross the boundaries of the cosmetic units when performing surgical reconstruction; the resulting scar should be placed within the natural junction or the boundary line of these cosmetic units or entirely within one cosmetic unit. If this is not possible, tissue from the adjacent unit may be borrowed for surgical repair. When a significant portion of a cosmetic unit is missing, the optimal repair choice may be to replace the entire cosmetic unit. By taking into consideration the gradations in skin color and texture, which vary from cosmetic subunit to subunit, along with elasticity and tissue movement properties, which vary from individual to individual, the effectiveness and the aesthetic outcome of the surgical defect repair may be greatly enhanced. Important contour lines that the reconstructive surgeon should be familiar with include the following:
In addition to the junction lines listed above, regional units, such as the scalp, the forehead, the eyelids, the nose, the lips, the chin, and the cheek, contain landmarks and subunits that should be familiar to the reconstructive surgeon.
SKIN TENSION LINESSection 5 of 10
The face can be mapped into a series of lines based on the direction of tension. Relaxed skin tension lines run perpendicular to the underlying facial muscles. Surgical incisions should be made parallel to the relaxed skin tension lines for optimal scar placement and aesthetic outcome. Skin tension lines should be considered in conjunction with aesthetic units when planning surgical repairs. Because of underlying structures and muscle contraction, the pattern and the extent of facial wrinkling varies in individuals. Elasticity and extensibility are also important factors when determining incision placement. Every effort should be made to put the long axis of the excision and closure parallel to the relaxed skin tension lines. This method results in closure under the least amount of tension, leaving the least noticeable scar. To determine the direction of the relaxed skin tension lines, one can have the patient contract his or her facial muscles, use oblique lighting, or pinch the skin. The skin tension lines can vary from individual to individual based on the underlying muscles of facial expression. Generally, the lines are more discernible in older patients and more obscure in younger patients. Marking the skin tension lines prior to surgery may be helpful because local anesthetic injection and tissue excision may alter them. Undermining the surgical defect in all directions may allow the defect to become oriented in the most favorable direction of closure. FREE MARGINSSection 6 of 10
Areas of the face that offer little or no resistance to oppositional forces are known as free margins. Free margins are characterized as the skin around an orifice; locations include the lips, the eyelids, the rim of the nostrils, and the helix of the ears. In defect management, a small amount of tension can pull a free margin away from its original location, resulting in cosmetic and, at times, functional defects (ie, pull on the lower eyelid can result in ectropion and dryness of the eye and, if not managed medically or surgically, can result in keratitis and blindness). To minimize the risk of functional and cosmetic deformities that arise from primary or secondary movement, flaps or grafts may be used. The appropriate reconstructive option depends on the location and the nature of the defect. If sufficient tissue laxity is available, appropriately planned advancement, transposition, or rotation flaps may reorient skin tension to avoid pull on free margins. If sufficient tissue laxity is not available, a skin graft may be required. Full-thickness grafts are preferable to split-thickness grafts because split-thickness grafts can contract significantly during the wound healing process, resulting in pull on free margins if placed in relatively close proximity. CONCLUSIONSection 7 of 10
When surgical defects are repaired, understanding the anatomical, functional, and aesthetic relationships that exist between the structural components of the face is important. Although one technique may be preferred over another in terms of managing a given defect, the planning and performance of any reconstructive procedure must take into account the principles of aesthetic units, relaxed tension lines, and free margins. A solid understanding of the basic principles of tissue movement and an assessment of the variability of tissue movement from patient to patient maximize the probability of an optimal cosmetic and functional outcome. ACKNOWLEDGMENTSSection 8 of 10
The authors and editors of eMedicine gratefully acknowledge the contributions of previous author, Halland Chen, to the development and writing of this article. MULTIMEDIASection 9 of 10
REFERENCESSection 10 of 10
Essentials of Tissue Movement excerpt Article Last Updated: Mar 27, 2008 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
