David Michael Tillson Department of Clinical Sciences, Auburn University, Auburn, AL, USA Mass excision is one of the most common surgical procedures in veterinary medicine. On the surface, mass excision is simple to accomplish, but so many factors can turn a simple procedure into a complex headache, resulting in angry clients, uncomfortable patients, and increased personal stress. The steps for a mass excision are planning, preparation, incision, dissection and hemostasis, wound closure, and postoperative management. This chapter will focus on these steps and they are all essential for the effective surgical management of masses. Some mass removals will be simple and straightforward, while others require detailed thought for each of the steps outlined, as there may be multiple techniques for managing them. To start, a brief review of wound healing will be included in a chapter focused on wound creation and reconstruction. Wound healing is divided into an inflammatory phase, a proliferative phase, and a remodeling or maturation phase.1,2 Each of these phases is characterized by some specific processes occurring during each phase of healing. It is clinically important to remember there are often multiple phases of wound healing occurring within a single wound simultaneously, as some areas of the wound progress faster than other areas. The ultimate goal of the surgeon when managing a wound is to promote effective healing while minimizing actions or conditions that would negatively impact wound healing. The inflammatory phase occurs immediately after wounding occurs. There is trauma to vascular structures, resulting in vasoconstriction followed by vasodilation and clot formation that creates the fibrin meshwork for future cell migration. Leukocytes, monocytes, and neutrophils begin to move into the wound bed within 30–60 minutes after injury. The neutrophils release proteinases that begin to break down damaged tissue. Monocytes activate, becoming tissue macrophages, and continue the process of transforming the wound environment into one that will promote future healing. Monocytes can survive the lower oxygen environment of a fresh wound while phagocytizing bacteria and other contaminants release proteases that continue the process of tissue debridement. Surgical debridement of necrotic tissue and wound lavage can reduce the workload on the macrophages and promote wound healing during this phase. Classically, the inflammatory phase continues for three to five days; however, increased wound contamination can prolong this phase. The proliferative phase starts as the inflammatory phase winds down, typically around four days after injury. Macrophage‐released cytokines stimulate fibroplasia and angiogenesis, which is characteristic of this stage. The proliferative phase includes the processes of neovascularization, or angiogenesis, fibroplasia and deposition of collagen within the wound, the migration of epithelial cells over the wound surface, and wound contraction. Neovascularization begins in response to low oxygen tension within the wound bed, stimulating the release of angiogenic factors from tissue macrophages within the wound. These factors stimulate vascular ingrowth and the formation of the capillary loops associated with granulation tissue. This vascular ingrowth is critical since fibroplasia and collagen deposition are dependent on an oxygen‐rich environment. Fibroblasts migrate along the fibronectin mesh left over from the wound clot and begin to secrete the fibronectin extracellular matrix followed by type III collagen. Type III collagen is eventually replaced by the more organized, stronger type I collagen; this process will continue into the maturation phase before it is completed. Epithelization starts along the wound edges within days of injury as the cells begin to proliferate and start moving over the surface of the wound. Epithelial cells undergo morphologic changes as they migrate into the wound, becoming larger in size and flatter, less plump than normal epithelial cells. While sutured wounds may have epithelial coverage in as few as two days, open or problematic wounds or those with necrotic tissues, foreign debris, or infection may result in the epithelialization process continuing into the maturation phase or later. This type of migrating epithelial surface is initially very thin and fragile. It is easily traumatized, which may lead to chronic problems with tissue injury, requiring wound revision or placement of a full‐thickness skin flap or graft for optimal function. If epithelialization has occurred but the collagen deposition within the wound bed is insufficient, the phenomenon of “pseudo‐healing” may occur. Pseudo‐healing is when the wound appears to be grossly healed, but due to minimal tissue strength, the wound easily reopens. Pseudo‐healing is reported to be a substantial issue in cats3 and can be encountered in dogs as well, especially those dogs with a history of chronic glucocorticoid steroid use. Wound contraction occurs when the wound bed decreases in size as the contraction process moves the full‐thickness skin surrounding a defect toward the center of the wound. This action decreases the distance epithelial cells must cover in the process of healing. This centripetal tissue movement begins during the proliferative phase as a result of the contraction of fibroblasts and myofibroblasts, and it typically continues into the maturation phase, moving at a rate of 0.5–0.75 mm per day and continuing for up to six weeks.1,4 Wound contraction after that time should not be expected, and surgical intervention may be needed to achieve sturdy wound closure. Wound healing by contraction is very effective in dogs and cats when there is adequate skin available, such as wounds on the thorax or lateral flanks. Contraction results in a small scar with haired skin adjacent to the epithelial scar. However, if the opposing tension on the skin reaches an equilibrium with the contractile force generated within by the wound, the contraction process is halted. This typically results in a large open wound with an epithelial covering. This type of wound epithelialization creates a large area of hairless, depigmented skin covered by thin, fragile epithelial tissue. Thus, wound healing through contraction is typically better than simple wound epithelialization over a granulation tissue bed. Contracture is the term applied when wound contraction results in impediment of function, typically with movement of limbs, due to excessive tissue contraction and subsequent scarring. This is commonly encountered with large wounds left to heal on their own or those that are near high‐motion areas. In cases of severe contracture, surgical revision may be required to restore some of the normal function of the affected area. The remodeling (maturation) phase can begin as early as 20 days after wounding and extend up to a year. During that time, the collagen deposition and resorption replaces type III collagen with the stronger, more organized type I collagen slowly increasing the wound tensile strength. Most wounds only achieve 70–80% of their original wound strength. At the same time, the proliferative capillary bed of granulation tissue gradually regresses toward the normal vascular arrangement. Chronic wounds may undergo a similar regression of the vascular bed, resulting in tissue that is incapable of supporting grafts or other efforts at getting the wound to heal. If further surgical intervention is planned, the wound should be freshened through the removal of the granulation bed then giving the wound four to seven days to establish a new bed of granulation tissue. With a new bed of granulation tissue, the wound is prepared for and supportive of primary wound closure or wound closure with flaps or grafts. Mass excisions are often seen as uncomplicated surgical procedures, and while many of them are, even small or moderately‐sized masses can be challenging to remove without complications. This is because factors, such as the biologic nature of the mass or mass location, may complicate the surgical procedure or the postoperative period. Non‐surgical factors, such as patient health status, owner expectations, and budgetary restrictions, can also create complications for the patient, owner, and surgeon. For small animal patients, location is one of the primary considerations when planning a mass resection and subsequent wound closure. Mass resections on the thoracic wall or abdominal flank offer substantial skin to permit primary wound closure. Distal limb masses have little extra skin for reconstruction and may require the use of flaps, grafts, or even open wound management to achieve wound healing. Furthermore, locations near joints must be able to withstand the constant tension on the wound from the animal’s normal activities, even when an owner complies with efforts to restrict activity, and locations over pressure points, such as the elbows, sternum, or hip, must be able to heal despite constant pressure on the wound. The ability of the veterinarian to protect the surgical site can also be complicated by the location. Inguinal wounds, especially in the male dog, can be difficult to bandage. Limbs can be bandaged, but bandage management is time‐consuming for the veterinarian and the client, and bandage‐related complications are common and can have devastating results. Planning is essential to surgical success and can give the client realistic expectations about the postoperative path to wound healing. “Surgical margin” is the term applied to how much tissue is removed along with the target mass. Some refer to margins as the “surgical dose” and try to determine the appropriate dose for each patient and for each tumor type. Various descriptions can be found on surgical margins.4 Intralesional resection is often referred to as “debulking,” and there is typically gross disease or bits of the mass left behind after the resection of the target tissue. Marginal resection is a limited resection, and it may be the most misused surgical procedure. With the marginal resection, the mass is removed at the level of the pseudocapsule surrounding the mass. There is residual, microscopic disease remaining in the wound bed. As with the debulking procedure, this is likely to lead to the re‐establishment of any aggressive mass in the same location. Ideally, a marginal resection is only used for benign masses or for tumors that will be subjected to other means of control, such as radiation or chemotherapy. If the biologic nature of the mass is unknown prior to excision, it is better to perform a wider resection. A wide resection is a larger dose of surgery, and it is the recommended technique when removing malignant tumors or masses of unknown etiology. Typically, a “wide margin” involves resecting 2–3 cm of normal tissue surrounding the target mass and taking a deep margin, defined as removal of a fascial tissue plane beneath the target. A wide margin may still have local, residual neoplastic tissue, especially with spindle cell neoplasms that have branching projections radiating from the neoplasia. A radical resection should result in no localized, residual neoplastic tissue remaining on the patient; however, to accomplish this, there is the loss of a substantial volume of normal, unaffected tissue. Examples of a radical resection would be an amputation or hemipelvectomy for a distal cutaneous sarcoma or a lung lobectomy for a peripheral lung nodule. The significant morbidity associated with performing a radical resection may dissuade owners from pursuing this option; however, it is often the recommended technique to effectively manage a malignant tumor. At the same time, the nature of a radical resection also requires the veterinarian to have definitively diagnosed the offending mass, to make sure other management options are not available, and to then present all options to the owner in order to meet the expectation of having obtained informed consent before surgery. Any limitations on the effectiveness of a mass excision must be discussed with owners prior to surgery. When a patient has a mass of unknown etiology, which could require a radial resection, i.e., amputation, to obtain adequate margins, the author believes incisional biopsy or a marginal resection would be warranted prior to the radical surgery with the client’s understanding that the more aggressive surgical procedure would be needed if the mass is deemed malignant. The effectiveness of a surgical margin in managing a mass is based on the histopathologic description of the mass.4 An incomplete margin is reported when the targeted tissue reaches the cut edge of the histopathological specimen. If the target tissue is less than 3 mm from the cut edge, the margin is noted to be narrow, while specimens with more than 3–5 mm of normal tissue between the target tissue and the cut edge are considered to have been completely resected. These descriptions take into consideration the potential for tissue shrinkage at resection and during specimen fixation, staining, and processing.5,6 Based on the tissue diagnosis and the accompanying descriptions, the veterinarian needs to determine if the resection was effective or if additional surgery or other treatment methods are needed. The above statement emphasizes the need for appropriate histopathologic evaluations of all resected masses. In the author’s referral practice, the surgeons are frequently told that the original mass was “tossed in the trash” at the time of their first surgery and that no histopathologic diagnosis is available. While histopathology is an additional expense, it is an important diagnostic test and should be standard for any mass resection. One approach is to not break out the histopathologic submission as a separate charge, but rather include it as a part of the surgical fee. This way, the surgeon is less likely to be swayed by the client to not submit the mass for the sake of costs. Another method is to take advantage of state diagnostic laboratories that, while slower than commercial laboratories, often offer a bargain price for histopathologic evaluations. A couple of final planning considerations are associated with a decision to remove multiple masses during a single procedure. The first is that this may require unique positioning and draping, or it might be determined that patient repositioning, along with re‐prepping and re‐draping, would be the most efficient and effective way to manage this. The operating room staff should be prepared for this step, and the surgeon will need to determine if they need to rescrub as well. Next, whenever multiple masses are being resected during a single procedure, the surgeon must decide the order of attack. Ideally, any benign masses should be removed first. The progression should then be to those with a greater potential to be malignant. If the malignant mass must be resected first, there should be a change out of instruments, gloves, and any other materials that came into contact with the suspected malignant mass. This will reduce the potential for surgical transfer, or “seeding,” of the secondary wounds with tumor cells from the primary tumor. The third concern when removing multiple masses is the effect each resection will have on the adjacent resection sites (i.e., will the closure of one site impact the planned closure of the other sites?) (Figure 18.1). If the plan to close one surgical wound ends up using the loose skin that was also part of the plan to close the additional surgical wound, the surgeon will need to modify their plan on‐the‐fly. This situation can be challenging to anticipate but is an important consideration in surgical planning. Surgical preparation for a mass excision begins with clipping of the patient’s hair in the necessary surgical field. In the planning stage of the mass excision, the boundaries anticipated should be clearly defined for the technical staff that is preparing the patient. Hair removal needs to be sufficient to prevent pulling unprepped skin into the surgical field as skin is advanced for wound closure. It is also useful to secure the field drapes with extra towel clamps or skin staples to minimize this issue. Another technique would be to have additional drapes or sterile surgical towels to cover any unprepped skin pulled into the primary field during wound closure. Figure 18.1 When planning to close multiple wounds or to resect multiple masses, the surgeon must consider the effect closing one wound will have on the availability of tissue and the surgical plan for closing any additional wounds. In some settings, combining multiple small resections into a single larger wound may allow for a more effective closure. In this image, the closure of the more difficult wounds on the right lateral hindlimb and right axillary areas (asterisks) utilized all the easily available tissue, requiring that the thorax and flank wounds to be managed in an open manner for an additional period of time. Once the surgical field has been clipped, the surgeon should review their surgical plan before moving to the OR. This may include using a marker to diagram the proposed procedure, including the primary incision and excision of the mass, the location, and the extent of any flap intended for primary closure. Diagramming out the proposed incision(s) with a sterile marker on the skin is useful and helps ensure the plan is appropriate and achievable. Peri‐operative planning also includes the potential need for wound drains, wound diffusion catheters for administration of analgesics, supportive bandaging, or limb immobilization. During the patient prep, the surgeon should anticipate and clip for any of these needs, as well as make sure that all appropriate materials are available in the OR. Once the patient is moved into the OR, a final skin prep is performed with the antiseptic of choice. While the author’s practice primarily uses chlorhexidine‐based antiseptics, some prefer to use a final application of an iodine‐based antiseptic, as the distinctive iodine color helps to confirm the surgical field is ready. Regardless of the product used, it is important to make sure there is no standing fluid on the field and that the surgical field is allowed to dry prior to surgical draping. Many practices use a surgical checklist, and this is the point in the procedure where the checklist is reviewed with the OR staff.7 Once the checklist is completed, the surgeon can begin the procedure. After the patient draping is completed and the surgical field established, the surgeon starts their incision. If the goal is a wide surgical margin, the proposed incision lines should be drawn out on the patient with a sterile surgical marker. Most of these markers come with a paper ruler, allowing the surgeon to accurately determine measured margins around the mass (Figure 18.2). Other surgeons use a graduated scalpel handle for measurements or a premeasured digit. Sutures, staples, or electrosurgery spots can be used to mark the patient’s skin along the proposed margin. Once the margins have been marked, the surgeon determines the best shape for the complete skin incision. This is important since following the margins around a mass will typically result in a circular wound, which is a difficult shape to effectively close. There are a variety of shapes for a surgical wound that will both maintain the desired margins and allow for advantageous wound closure. Most surgeons will try to modify the circular wound into an elliptical or fusiform‐shaped wound, although the use of flaps can force this plan to be modified. Ultimately, the final wound shape is influenced by skin tension lines, adjacent structures, or other wounds that may exist or be created. Figure 18.2 Once the surgical field is established, the surgeon should use a sterile marking pen to determine the margins for a mass resection. Using the sterile ruler supplied with many markers ensures that accurate margins are drawn prior to wound resection. A variety of scalpel blades can be used for the skin incision associated with routine mass resection. The typical #10 blade is good for longer incisions, while the #15 blade is normally used for shorter incisions. The author has started to more frequently ask for a #11 blade for more precise incisions and for undermining tissues. Electrosurgical devices or CO2 lasers can also be used for creation of the surgical incision; however, the author minimizes direct incision with either, preferring to use the scalpel through the epidermis and dermis and then switching to electrosurgery for continuing the incision. If either electrosurgery or CO2 lasers are being used for primary incision, the surgeon should be comfortable with the guidelines for usage and wound closure. When performing the incision for a mass resection, care is taken to have the scalpel blade maintain a perpendicular orientation to the skin surface. Failure to maintain this orientation results in beveling of the skin incision, especially as the incision curves around the mass. A beveled wound edge is more challenging to close, can result in gaping along the wound edge, and can shrink the intended surgical margin. Using the fingers of the non‐dominant hand, tension can be placed across the proposed incision site. The fingers are moved as the scalpel advances, maintaining this tension, which encourages the easy separation of the wound edges during incision. As with all surgical incisions, the surgeon must carefully adjust the pressure on the blade to accommodate the skin thickness and the potential for injuring tissues beneath the incision. Once the initial incision has been created, modifications can be made as required for better visualization or improved wound closure. The final incisional adjustment may occur as the surgeon is adjusting the wound conformation for closure. Gentle tissue handling is an essential component of wound reconstruction and closure. Aggressively grasping the edges of the wound or of flaps being developed can result in damage to the tissue and the associated vascular supply. While using thumb forceps, there is a natural tendency to grasp tissues tighter when struggling with them, this can result in excessive tissue trauma to the skin edge. Thumb forceps with worn, dulled, or no teeth actually cause the surgeon to increase the pressure on the tissues being held. To minimize trauma to the wound edge, it is recommended that the surgeon takes care to avoid excessive skin manipulation with forceps. A method to minimize repetitive grasping of a skin edge is to use items that can be left in place in the wound edges for manipulation, such as stay sutures placed at the corners of flaps or the use of skin hooks, specialized skin forceps (e.g., LaLonde forceps), or even penetrating towel clamps to manipulate tissue edges (Figure 18.3). Crushing clamps (e.g., Allis tissue forceps) or hemostatic forceps can be used to grasp the mass and any resected tissue surrounding it, but they should not be used on the incision edges. Figure 18.3 Instruments with sharp points often create less trauma to a wound edge than do normal tissue forceps. This is especially true if there is significant tension, as this causes the surgeon to exert significant force on tissue forceps to maintain a grip on the tissue. (a) Skin hooks. (b) LaLonde tissue forceps. These forceps have skin hooks rather than teeth and have a carbide insert to grasp the surgical needle. (c) Backhaus towel clamps are routinely used to hold tissue edges during dissection. Additionally, they can be used to hold tissues in apposition while trying to determine the best method of wound closure. Tissue dissection and undermining are essential skills for mass removal and subsequent wound closure. This can be accomplished using a sharp scalpel blade, Metzenbaum scissors, or electrosurgical instruments.8,9 In the author’s opinion, a combination of these instruments will probably provide the best results for effective dissection. Sharp dissection is effective and gives the best tactile feedback during dissection but can result in more hemorrhage from the transection of the numerous small vessels in the subcutaneous space than would be encountered with electrosurgery. Using electrosurgery will minimize capillary and small vessel hemorrhage, thus reducing the potential for hematoma formation; however, it does create carbon residue or char that remains behind. Excessive char, typically created by inappropriate electrosurgical or laser settings, increases inflammation and may negatively impact wound healing. Judicious use of the electrosurgical device at appropriate settings and generous lavage of the subcutaneous space will help reduce the remaining char prior to closure. A principle of dissection that is underappreciated is the use of “traction‐countertraction.”10 This simple technique enhances the precision of tissue dissection by using gentle tension to separate the various tissue planes more easily. The surgeon places tension on one side of an incision, while an assistant provides traction in the opposite direction (i.e., “countertraction”). This is the same principle being used when the non‐dominant fingers are used during the initial skin incision. This traction‐countertraction helps define tissue planes and keeps the surgeon from deviating in a manner that could compromise the development of tissue margins around a mass (Figure 18.4). Hemostasis during dissection can often be managed exclusively by the use of electrosurgery, or it may be achieved by small vessels being crushed with hemostats or by large vessels being ligated by suture, clips, or bipolar vessel sealing devices. Most skin masses do not require exceptional techniques for hemostasis; electrosurgery and a fine, short‐term absorbable monofilament suture will manage most situations. It is helpful, however, to employ caution during dissection. It is easier to identify and occlude a vessel before cutting it than it is to cut it and then struggle to find the bleeding end that retracted into the middle of the tissue dissection! It is also important to remember that most neoplastic masses will develop an increased blood supply through increased vessels leading to and from the mass (i.e., neovascularization). Be prepared for more hemorrhage than normal. Figure 18.4 Using “traction and countertraction” allows for effective dissection of soft tissues and aids the surgeon in staying within the optimal tissue plane. This is accomplished by the surgeon gently placing tension on the tissues on their side of the surgical wound and having their assistant gently retract in the opposite direction. An experienced assistant will move with the surgeon, maintaining a 180° position to maintain effectiveness. Wound closure options range from simple to complex; however, the principles of wound healing are essentially the same no matter the method of closure. They include gentle tissue handling, effective dead space closure, tension‐free wound closure, and accurate wound apposition. Striving to adhere to these principles should maximize the potential for trouble‐free wound healing.8–11 The “rule of ½” is a suturing technique that helps create accurate wound apposition and decrease tension across the surgical wound during closure. The first suture is placed in the center of the incision, effectively dividing the length into halves. The next sutures are placed in the center of each half, dividing each half in half again; the incision is now divided into quarters. This process is repeated, until the wound is closed. This technique is especially helpful in managing tension and improving the spacing of skin sutures along the incision. Undermining and advancement of the wound edges can be useful in closing wounds after mass resection. In small mass resections with minimal or wide margins, undermining the adjacent skin and subcutaneous tissue releases it and allows one wound edge to be moved toward the opposite wound edge. The principles of dissection given earlier in the chapter should be adhered to when undermining the wound edges. Once the skin has been freed sufficiently to permit wound edge apposition, additional dissection will simply create dead space for seroma or hematoma formation. Subcutaneous sutures (see details below) should be used to decrease dead space in the wound and bring the wound edges closer together for better apposition and a tension‐free closure. Relaxing/releasing incisions can be either small, punctuate incisions or a longer, full‐thickness incision made through the skin adjacent to the wound closure.8–10 With either, the aim is to release some of the tension across the wound by allowing a longitudinal incision, made perpendicular to the tension line but parallel to the long axis of the wound, to expand from a slit to a diamond (Figure 18.5), creating a small to moderate amount of release. When small, punctuate, relaxing incisions are used, they are made by cutting through the skin into the subcutaneous tissue with a #11 scalpel blade. The number of relaxing incisions will range from a few to a dozen or more incisions on either side of the wound. These small relaxing incisions are allowed to heal through secondary intention healing, so no additional surgery is required. Larger releasing incisions can run the length of the original wound. These incisions can also be allowed to heal by secondary intention, or, if the causes that inhibited primary closure of the original wound have been eliminated, primary closure can be considered. Figure 18.5 “Relaxing incisions” are small incisions created in the skin adjacent to the primary wound (a). When the primary wound is closed, the relaxing incisions expand (b) to allowing the apposition of the wound edges with minimal tension. Subcutaneous sutures are important for successful wound management, especially when skin advancement or reconstructive procedures are being performed. Different subcutaneous suture patterns can be used to accomplish different tasks during wound closure. The most basic suture pattern is a buried, simple interrupted subcutaneous suture. This suture type is generally placed to help decrease dead space through the apposition of subcutaneous fascia and adipose tissue. There is some benefit at reducing future tension when the overlying skin is subjected to motion in the awake animal. Normally, the author uses a small, 3‐0 to 5‐0, short‐term absorbable suture material for all the various subcutaneous patterns. Poliglecaprone 25 (Monocryl®; Ethicon, Somerville, NJ) is the author’s “go‐to” choice for subcutaneous sutures; however, sometimes, it is the multifilament, polyglactin 910 (Vicryl®; Ethicon, Somerville, NJ) suture that is chosen for its handling characteristics and knot security. Monocryl and Vicryl have a short duration in tissues, losing >50% of their tensile strength by 21 days and undergoing complete absorption by 120 and 70 days, respectively.11 Only when there is a significant concern for delays in wound healing would a longer‐lasting suture material be required for subcutaneous placement. “Walking” sutures are another subcutaneous suture pattern that is used to advance a skin edge toward the opposite side for closure and to counteract tension within the wound.8–10 The suture pattern is accomplished by pulling the skin edge back and exposing the underside. A suture bite is directed from within the incision outwards, taking a bite of the dermal layer in the process. The suture needle is pulled free and the next bite is taken in some sturdy subcutaneous tissue or deep fascia coming back toward the first bite (Figure 18.6). This allows the suture knot to be buried within the deep tissues. When the walking suture’s dermal bite is placed several mm (5–10 mm) laterally to the fascial bite, the process of tightening the suture will pull the dermis toward the center of the wound. These steps are repeated in a methodical pattern to slowly advance the wound edge further and further toward the center of the wound. Correctly placed, walking sutures can advance a skin edge of a wound dramatically, ultimately allowing the skin edges to be in close application without excessive tension, while also reducing dead space in the wound bed. If the placement of the walking sutures tries to advance the tissues too aggressively or they are not anchored securely to fascia or in the dermis, suture pull‐out will occur. If there is limited tissue available for a solid suture purchase, more sutures should be placed with each suture advancing the wound edge a shorter distance. This will accomplish the same objective. Figure 18.6 Walking sutures are used to advance tissues toward a central point and to assist in the closure of dead space. (a) When a walking suture is placed, the first bite is through the dermis (A), and the next bite is taken through the fascia (B). The fascial bite (B) is taken 5–10 mm ahead of the dermal bite (A) in the direction of skin advancement. (b) When the suture is tightened, the dermal bite (A) is drawn forward toward the fascial bite (B), advancing the skin edge. Multiple rows of walking sutures may be required to advance wound edges sufficiently to close the primary wound. Pulley sutures are another subcutaneous suture pattern that will help appose a wound while overcoming the tension within the wound.12 A subcutaneous “pulley suture” involves taking a double pass with a suture needle on each side of the wound. Each suture bite must engage sturdy tissue, or pull‐out is likely to occur. Specifically, the surgeon takes a deep to superficial bite on the near side, then takes a superficial to deep bite on the far side. At this point, it is the same as a buried knot. The difference with a modified pulley is that a second pass, running deep‐to‐superficial (near side) and superficial‐to‐deep (far side), is taken. It is important to pass the second bite immediately adjacent to or even in the same plane as the first suture passage. Spreading the bites apart seems to reduce some of the effectiveness of the pulley suture. Both the suture tag and the needle end should come through the middle of the suture pattern. The suture is slowly tightened until the degree of closure desired is achieved, and a knot is tied. The pulley suture can overcome significant tension within a wound bed and is especially helpful for wounds like unilateral or bilateral mastectomy. Multiple sutures should be placed until the skin edge has been advanced sufficiently to permit closure (Figure 18.7). Based on the needs of a particular closure, the pulley suture can be used in a similar manner to the walking suture, to help with the initial mobilization of the skin edges for closure. Pulley sutures and walking sutures can also be in open wounds to help prevent retraction of the wound edges during initial management. Figure 18.7 Pulley suture. Pulley sutures are typically used when the skin around the surgical wound is plentiful, but it will be under tension when apposed. The placement of several pulley sutures in a wound can bring the skin edges closer, neutralizing the distractive tension. Pulley sutures can also be combined with interrupted subcutaneous sutures or walking sutures for optimal results. (a) The first pass is deep to superficial to bury the knot on the near side. (b) A superficial to deep bite is taken on the far side. (c) The next pass is taken immediately beside (or even in the same plane as) the first bite. (d) The final pass is superficial to deep immediately beside (or in the same plane as) the second bite. It is important to keep the suture passes closely associated to maximize the benefits of the pulley suture. Advancement, transposition, and rotational flaps are skin flaps that rely on the subdermal plexus of vessels for the survival of the overlying skin. It is this reliance that limits these flaps. As the flap is developed, the blood supply is severed on three sides, with only the vessels crossing the flap base onto the pedicle remaining. While it was once felt there was an ideal width‐to‐length ratio for a pedicle flap, it appears, within reason, that the survival of these flaps is based more on the characteristics of the subdermal plexus in the immediate area rather than the width of the base or the length of the flap.8,13–15 The same flap, created in two different locations, may have different clinical outcomes. The primary indication for the use of skin flaps during a mass resection is the potential for the flap to allow a more effective tension‐free closure of the wound created during removal of the mass. This may be in the form of (1) bringing healthy skin into a compromised area, (2) releasing excessive tension on the surgical wound, or (3) allowing closure of a difficult spot in a single session. Despite these advantages, the process of flap creation increases the amount of surgery a patient is receiving; therefore, flaps should be used only when necessary, relying on simpler closure techniques when appropriate. The skin has a rich vascular supply; however, this vascular support can be easily disrupted, impairing the health of the skin the surgeon is relying on to close the wound. The normal vascular supply to the skin begins with the direct (deep) cutaneous arteries.11 These arteries supply specific zones within the skin and subcutaneous tissue and are the basis for axial pattern flaps. The direct cutaneous arteries give rise to a mid‐level arterial supply to the skin that further branches into the small vessels or capillaries in the dermis. These form a meshwork of small, anastomosing “subdermal” vessels that support the overlying skin. The subdermal plexus can be damaged during manipulation, but the meshwork nature of these vessels and their inherent redundancy give the skin resilience. However, when a flap is elevated, this redundancy and resiliency are diminished; thus, adherence to the Halstedian principle of “gentle tissue handling” to protect the blood supply to a skin flap is essential to optimize healing. Many of the techniques for gentle tissue handling, discussed earlier in the chapter, become even more important when dealing with flaps. When dealing with skin flaps, the “delayed phenomenon” is a technique used to enhance the vascular support of a planned subdermal plexus flap.16 This is a two‐step process that begins with elevation of the planned flap, including freeing of the skin from the underlying subcutaneous tissue, and then replacing the flap in its original location. The flap is sutured back in place and allowed to heal. This time stimulates the skin to reestablish a more robust subdermal plexus to support the overlying skin. In a few weeks, a second surgery is performed with resection of the target mass, and the flap previously elevated is again elevated, incising along the same lines as the previous surgery. The flap is then shifted to the recipient bed and sutured into place. Flap survival is expected to be improved with this technique. The primary disadvantage of the delayed transfer technique is the requirement for it being a two‐stage process; requiring two separate surgical procedures before a mass can be resected and the wound closed. Subdermal plexus flaps are what most veterinarians think of as skin flaps. These flaps are variations of advancement flaps, transposition, and rotational flaps. These flaps rely on the normal subdermal vascular plexus in the skin to support the flap.14,15,17,18 For that reason, they need to be planned prior to development, and care must be taken during manipulation of the flaps to avoid injuring the subdermal plexus, as this will increase the potential for primary wound dehiscence. While there are numerous variations on subdermal plexus flaps, this discussion will focus on advancement flaps, such as the single‐pedicle flap, the “H‐plasty,” the bipedicle flap, and the rotational flap. Single‐pedicle advancement flap is the most common flap for wound closure.8,11,15,17–19 It involves the creation of a skin flap from the available skin immediately adjacent to the wound bed to be closed. The length of the flap is created by extending parallel incisions away from the wound bed that are 1–1.5x the length of the wound bed to be closed. It is important that the base of the flap is maintained at least the width of the original flap, although the author tends to widen the base slightly (Figure 18.8a). After the flap is elevated, the only remaining connection to the subdermal plexus is across the base of the flap, so keeping it as wide as possible should be beneficial. Advancement flaps tend to create “dog‐ears” at the point where the flap slides onto the wound bed. Most of the time, these can be left in situ, and they will smooth out as the healing process continues; however, if resection of the dog‐ears is attempted, it is essential that the process does not impinge on or diminish the base width of the advancement flap. Metzenbaum scissors or a scalpel blade is used to undermine the proposed flap, releasing it from any subcutaneous attachments, and the flap is advanced toward the far side of the wound bed. The author uses a combination of interrupted, subcutaneous, and walking sutures (Figure 18.8b) to advance the flap until it reaches the point of close apposition to the target edge in a relatively tension‐free manner. This means the flap should maintain its position when it is released from external forces; if the flap retracts substantially, additional supporting sutures are needed to address the tension. H‐plasty advancement flaps are a modification of the single advancement flap.8,14,16,17,19 This flap, also referred to as a double advancement flap, elevates two opposing subdermal advancement flaps, allowing the length of each flap to be more conservative than a single advancement flap would need to be. The shorter flaps are less likely to exceed the capacity of the subdermal plexus to support them once they are advanced. Once the flaps are elevated, they are advanced toward the middle of the defect, using a combination of subcutaneous, interrupted, and walking sutures to counteract any retraction. The flaps are advanced until they can be apposed without tension, and skin sutures are placed for final apposition of the first flap to the flap from the opposite side. Skin sutures are then continued along the incision lines created when the flap was raised. The final incision’s appearance is a capital “H.” The main advantage of the “H‐plasty” is reducing the length of a single flap that would be required to close an incision by using two shorter flaps. In addition to improving the vascular support with a shorter flap, this technique should also reduce the tension on the final closure. Figure 18.8 Single pedicle advancement flap. (a) During the planning stage, the surgeon must check tension lines of the skin (brown lines) to ensure there is sufficient skin available for the flap without excessive tension. (b) The flap is created by making parallel incisions that develop a flap at least 1–1.5x the length of the defect to be closed. (c) The flap is undermined and advanced using subcutaneous sutures to eliminate tension. The flap is stretched until it apposes the distant wound edge. (d) The wound edges are apposed to the flap edges for final closure. Additional wrinkles or “dog ears” created by the advancement of the flap can be cut off or allowed to remain. A bipedicle advancement flap uses an adjacent, releasing incision to create the flap. First, the length of the wound, as measured along the long axis, is determined.8,15,17,19 The releasing incision is made parallel to this long axis at a distance that is ½ of the long axis length from the wound bed (Figure 18.9). The skin between the wound bed and the releasing incision is undermined, creating a skin flap anchored at each end. The bipedicle flap is then advanced laterally, over the wound bed and sutured in place, covering the exposed bed. This process obviously creates a secondary wound to be closed. Ideally, the change in location of the defect will permit the definitive closure of the secondary wound. The ability to close this wound could be possible because the flap bed wound may not be constrained by the same factors that prevented closure of the primary wound and necessitated the bipedicle flap usage. These could be issues with wound tension or concerns about movement prompting use of the flap, which may not be the situation for the new location of the flap bed wound because of more availability of adjacent skin for closure or the use of the bipedicle flap could move the wound away from a high‐motion zone. One final reason to consider the use of a bipedicle flap, even if the secondary wound cannot be immediately closed, would be the option of closing the primary wound that may be in a sensitive area, such as exposed bone or tendon, exposed major vessels, or an open wound over an orthopedic implant. In this situation, once the flap is moved and the primary wound is closed, the secondary wound can then managed. Rotational flaps are most useful when the defect is triangular in shape.8,14 In describing this type of flap, the defect can be thought of as a wedge, and the flap is created such that the clockwise (or counterclockwise) rotation of the flap will “close the wedge.” To begin, the wound defect is debrided, and the wound edges freshened so the defect forms a roughly triangular shape. Using one of the long edges of the defect, a curving arc of the rotation is drawn beginning at the base of the triangle and creating a semicircular incision, which encompasses the wound defect at one end. The skin is undermined along the incision moving inward until the flap is freed. The flap is then pivoted into the defect, with the outer edge moving further than the inner edge, until the flap reaches the far side of the triangle and the defect is closed. Tension along the flap is controlled with subcutaneous sutures, as previously described, and the incisions are closed using an appositional suture pattern. Figure 18.9 “H‐plasty” advancement flap. (a) An advancement flap is outlined on opposite sides of a wound bed. Since two flaps are being elevated, the flaps are typically shorter than a single flap would be. (b) The flaps are undermined and advanced using subcutaneous sutures to eliminate tension. Each flap is advanced until they meet midway across the wound. (c) The flaps are apposed, and the edges are sutured to maintain apposition and positioning. (d) H‐plasty advancement flap prior to placement of the skin sutures. Transposition flaps are similar to advancement flaps, but they are developed at an angle to the recipient wound bed, generally between 45° and 90°.8,14 One side of a transposition flap will be the edge of the wound defect to be closed. This is in contrast to the advancement flap, where it is the leading edge of the flap that is one of the wound edges. Because a transposition flap will be raised and then rotated into the wound bed, it is important to check skin tension on all sides of the wound to determine which side is optimal for flap development. The transposition flap width is determined by the width of the wound bed. The length of a transposition flap is estimated by determining the distance from the far edge of the flap base and the farthest point away from the wound bed to the far side of the wound defect. The outline of the proposed flap is drawn adjacent to the wound, then the skin is incised and undermined. The flap can now be rotated into the wound bed, where it is secured with subcutaneous sutures. The flap edges are apposed with skin sutures, and the first portion is completed. Ideally, the open donor site from where the flap was elevated can be closed primarily to complete the procedure. As a subdermal plexus flap, transposition flaps need to have a substantial base to support the flap. Some surgeons consider the 90° rotational flap to be the most versatile.8,14 When raising a transposition flap on a limb, the base of the flap must be the most proximal point with the flap extending distally down the leg. With increasing rotation, the flap is more likely to suffer flap necrosis and incisional dehiscence. Closure of the donor site, when a flap is raised on a limb, is more difficult due to the limited amount of loose skin on the limbs. When moving the transposition flap into the recipient bed, the skin can bunch along the base of the flap. These areas, referred to as “dog‐ears,” tend to get larger the more the flap has to be rotated to fit into the recipient bed.14 Surgical removal of dog‐ears may create a more esthetically‐pleasing wound closure; however, there is little reason to actually remove them. Furthermore, careless action while trying to remove dog‐ears can impinge on the flap base, increasing the risk of flap necrosis. Axial pattern flaps are a unique subset of skin flaps in dogs and cats. An axial pattern flap is predicated on the presence of a specific artery, referred to as a direct cutaneous artery, that consistently supplies a specific area of skin. An axial pattern flap is typically named for the direct cutaneous artery supporting the flap. It is the presence of the supporting artery that allows for creation of a skin flap with a base‐to‐length ratio that would not be appropriate for a subdermal advancement or rotational flap. With an axial pattern flap, the length and width of the flap is only limited by the circulatory distribution of its supporting artery. Axial pattern flaps are typically rectangular in shape but some of the flaps can be extended at a 90° angle at the end of the flap, creating an inverted “L” shape for rotation into the recipient wound bed.20,21 The standard axial pattern flap is sometimes referred to as a “peninsula” flap. This term is applied since the standard axial pattern flap is a long strip of skin that maintains an attachment to the main body. This terminology differentiates the standard axial pattern flap from an “island” flap (to be discussed later). Table 18.1 summarizes the uses of and the surgical guidelines for elevating the caudal superficial epigastric flap (Figure 18.10), the thoracodorsal flap, the omocervical flap, the caudal auricular flap, the dorsal and ventral deep circumflex iliac flaps, and the related, flank fold flap.20–23 Details for other axial pattern flaps can be found in detail elsewhere.8,20,21 The versatility of the axial pattern flap allows the surgeon to employ it for difficult areas to reach or challenges in wound closure. The most common usage is where the flap is raised, its base is maintained, and then the flap is rotated into a wound bed. This can be done with more chronic wounds after open wound management or with acute, surgical wounds. Care needs to be taken whenever the plan is to employ an axial pattern flap for closure of a traumatic wound. There is a risk that the traumatic episode could have damaged the direct cutaneous artery that supports the flap, rendering the axial pattern flap into a simple rotational flap. In this circumstance, there is likely to be significant necrosis of the flap and wound dehiscence. The advantages of axial pattern flaps include the ability to combine the initial mass removal with closure using an axial pattern flap, providing a single‐stage resection and closure of a surgical wound. This flexibility to provide a primary closure reduces the need for open wound management and the need for additional surgery, resulting in less cost and hospitalization time for the patient and client. Axial pattern flaps also offer the potential for primary closure of large wounds in a manner that minimizes tension across the site. Axial pattern flaps are consistent in their performance, as long as the surgeon follows the reported borders during flap development and is careful with tissue handling of the flap. When developed correctly, axial pattern flaps have a survivability rate of 85–100%, depending on the particular flap being used.20 The primary disadvantages of an axial pattern flap are the greater surgical dose, increased anesthesia time, and costs required to elevate and secure the flap in the recipient wound bed. Other disadvantages include the potential to disrupt the primary vascular pedicle during the elevation of the axial pattern flap with subsequent flap necrosis. Injury to the vascular pedicle results in two large defects to close rather than just the one, original defect. Flap necrosis can have numerous causes, but the most common causes are secondary infection, the surgeon failing to follow the guidelines for a specific axial pattern flap, and placing too much tension on the flap, which causes a reduction in flap perfusion. Appropriate perioperative antibiotic administration and judicious postoperative antimicrobial therapy can help prevent or treat bacterial infections associated with the flap. Early intervention to reduce tension, correct vascular pedicle occlusions, or relieve excessive fluid accumulations under the flap may help with salvaging a compromised flap. A closed suction drain is often placed at the time of flap development and suturing into the recipient bed, which will reduce the fluid build‐up beneath the flap. Additional therapies, such as hyperbaric oxygen and negative‐pressure wound therapy, have shown to have some benefits in human medicine, but the role and the benefit of these modalities in veterinary medicine remain unclear.20 Preoperative planning is essential for successful outcomes with axial pattern flaps. The anticipated origin of the direct cutaneous vessels should be carefully marked, followed by diagramming the borders of the proposed flap. The flap length must be measured to ensure it will be sufficient for the wound to be closed. This can be accomplished by using a 4 × 4 gauze, or similar non‐stretchy material, to represent the flap, anchoring it to the proposed flap base then rotating the gauze into the recipient wound bed. If the gauze bunches too much or is insufficient in length, changes need to be made to the plan. This could consist of (1) using a different axial flap, if available, (2) altering the length of the proposed flap within acceptable parameters, or (3) by determining a different closure technique may offer a better outcome compared to the planned axial pattern flap. Table 18.1 Common axial pattern flaps. If the recipient wound bed exists due to a traumatic wound, it will need to be managed until there is a healthy bed of granulation tissue. Once this is the case, a tissue culture should be obtained and the wound bed should be covered with a topical antimicrobial cream for 24–48 hours before the final procedure, and then it should be sterilely bandaged. Once in surgery, the wound edges are freshened, and efforts made to reduce the biofilm on the granulation tissue surface before transferring the axial pattern flap to the recipient bed. For standard axial pattern flaps, the attached base of the flap can rotate no more than 180° without risking compression of the vascular pedicle. Careful dissection of fat and subcutaneous tissue surrounding the vascular pedicle can reduce the pressure exerted against the pedicle when rotating the flap but this action increases the risk of iatrogenic damage to the vascular pedicle. Figure 18.10 The rotational flap is useful for closing triangular defects or defects that can be debrided to a triangular shape. (A) Flap shape and size are estimated by taking the wound bed and using the size to create an arc that pivots around the narrow point for 180°. (B) The line of the arc is incised, and the skin is elevated from the subcutaneous layer. The leading edge of the flap (a) is to be advanced to the far edge of the defect (a′). (C) The flap is advanced (point a meets a′) and secured in place with subcutaneous sutures and skin sutures. Vascular compromise associated with flap rotation is typically from compression of the vein draining the flap, since veins are low pressure, thin‐walled, and easily compressible. The result of venous outflow obstruction is mild to severe venous congestion of the flap, leading to flap necrosis. This can be treated by surgical means to relieve venous congestion (e.g., flap revision), flap drainage through the use of punctuate incisions to allow congested blood to escape into a bandage, or application of medicinal leeches (hirudotherapy).24,25 The more aggressive the axial pattern flap is rotated, the greater the risk of compromising the artery causing ischemic flap necrosis. To minimize this complication, an axial pattern peninsular flap that needs to have greater than 120° rotation can be converted to an axial pattern “island” flap allowing up to 180° of flap rotation (Figure 18.11). To create an axial pattern island flap,20,21 the surgeon first develops a standard axial pattern flap. After elevating the flap, the surgeon carefully severs the skin attachment at the flap’s base. With the base severed, the flap is now simply an island of skin that is only anchored by the vascular pedicle. This island of skin can be elevated and rotated up to 180° with less risk of twisting or compressing the vascular supply, potentially causing vascular compromise and flap necrosis. There is, however, an increased risk of surgically damaging the vascular pedicle of the supporting artery and vein during the dissection required to create the island flap. Finally, surgeons who are comfortable with microsurgical techniques may use an axial pattern flap as the donor flap for a free vascular graft. The consistent blood supply means the flap can be raised from the donor site, and the pedicle vessels are dissected clear and transected. The surgeon may now free up the newly created graft, which is transferred to a new location. Once the microvascular anastomosis between the direct cutaneous artery and vein of the graft and a recipient artery and vein is completed, the newly re‐vascularized graft should have consistent survival in its new location. Details of microsurgical graft transfers have been reported but are beyond the scope of this chapter. 26 Figure 18.11 (a) The length of the transposition flap is determined by measuring from the far corner of the flap base to the distant edge of the defect (green arrows). (b) The borders of the flap are incised, and the flap is elevated in preparation for rotation into the defect. (c) Once the flap is placed in the defect, it is secured with subcutaneous sutures followed by skin sutures. The donor site is closed primarily. When the wound bed that needs the axial pattern flap is not immediately adjacent to the base of the axial pattern flap, a “bridging incision” will be needed to move the flap into the correct position. The bridging incision is created by incising the skin and subcutaneous tissue between the base of the axial pattern flap and the recipient wound bed, permitting the flap to contact the edges of the bridging incision as it travels to the wound bed. The location of the incision should accommodate any anticipated tension or stresses from movement. Hemostasis is established but care must be taken to not compromise the primary blood supply to the newly raised flap. Once the flap is rotated into the recipient wound bed, it is secured in place. Some surgeons simply secure the flap in place with skin sutures (or staples) after placing an active or a passive drain in the recipient wound bed underneath the flap. The author prefers to use a combination of buried, simple interrupted sutures and walking sutures to decrease dead space under the graft and help dissipate any tensile forces on the flap, while the editor prefers to place a closed suction drain and not place walking sutures, which could increase the risk of flap vascular compromise if sutures grab any of the small vessels. Care must be taken to not damage or occlude the direct cutaneous artery when placing these sutures, or distal graft necrosis is likely to be the result.
18
Summary of Skin Reconstruction Options
Introduction
Basic Principles
Wound Healing
Planning
Preparation
Incision
Dissection and Hemostasis
Wound Closure
Advancement and Rotational Flaps
Vascular Supply to the Skin
Axial Pattern Flaps
Name
Borders
Uses
Caudal superficial epigastric flap
This flap is based on the caudal superficial epigastric vessel.
This vessel arises from the external pudendal artery as it exits the inguinal ring and runs cranially.
Base: Between the last mammary gland and the inguinal ring.
Central axis: The nipple line of the mammary chain.
Medial border: The ventral midline.
Lateral border: A parallel incision equidistance to the distance between the central axis and the ventral midline.
Cranial border: The flap can run cranially to the third or even extended to the second mammary gland in the dog and cat (i.e., glands 2–5 in the dog, glands 2–4 in the cat).
Can be stretched up to the dorsum in the flank area, rotated down the proximal portion of the rear leg to the stifle, or shifted anywhere within 180° of the base of the flap, including the perineal region.
Dissection should be deep to the mammary tissue.
Require a bridging incision to rotate into wound beds.
Caudal auricular flap
Based on the caudal auricular artery.
Base: Centered over the lateral wing of the atlas.
Cranial/Caudal incisions: Parallel incisions running caudally to the edge of the scapula.
Flap width: The width of the flap can vary but is typically 1/3–1/2 of the distance from the dorsal cervical midline to the ventral cervical midline.
Flap length: The edge of the scapula.
Wounds on the head (dorsal), neck, fascial area, and the ear.
Thoracodorsal flap
Based on a cutaneous branch of the thoracodorsal artery.
Creation of an “inverted‐L” shape is possible with this flap.
Base: Caudal depression of the shoulder (with the vessel just caudal to the acromion)
Central axis: Runs along the caudal border of the scapula
Cranial: From the acromion running dorsally along the spine of the scapula.
Caudal: Parallel to the cranial incision, equidistance from the central axis to the scapular spine (cranial incision)
Flap length: Can run dorsally to the dorsal midline or to the contralateral dorsal scapula; a “L‐shaped” flap can be raised along the dorsum with the short leg moving caudally
Shoulder, axilla, thoracic wall, upper arm, and forearm in cats and certain dog breeds.
Flap is raised deep to the cutaneous trunci muscle; the thoracodorsal artery is vulnerable to injury.
This flap can extend to the dorsal midline and even beyond, although the further over the dorsal it extends, the greater the risk for distal flap necrosis.
Deep circumflex iliac flap – dorsal branch
Based on the dorsal branch of the deep circumflex iliac artery.
Base: The artery exits the flank area just below the wing of the ilium. It branches into a ventral and dorsal branch. The central axis runs from the base dorsally along the cranial edge of the ilium.
Caudal: The caudal incision runs from the base dorsally between the cranial edge of the ilium and the greater trochanter.
Cranial: A parallel incision equidistance to the measured distance between the central axis and the caudal border (over the ilium).
Flap length: Can extend to the dorsal spine and over the dorsum to the flank fold on the opposite side.
Used for lesions in the ipsilateral flank, pelvic, lumbar, and defects of the greater trochanter and lateromedial thigh.
Deep circumflex iliac flap – ventral branch
Based on the ventral branch of the deep circumflex iliac artery.
Base: The artery exits the flank area just below the wing of the ilium. It branches into a ventral and dorsal branch. The central axis, for the ventral branch, runs ventrally toward the flank fold.
Caudal: The caudal incision runs from the base ventrally from a point midway between the cranial ilium and the greater trochanter. This incision runs parallel to the shaft of the femur.
Cranial: A parallel incision equidistance to the distance measured between the central axis and the caudal incision (parallel to femur).
Flap length: Can extend ventrally to the level of the patella.
Can be used as a rotational flap or as an island flap.
As a peninsula flap, it can rotate cranially or caudally to reach the lateral abdominal wall, flank, and lateromedial thigh; as an island flap, it can be rotated to reach lesions associated with the sacral and lateral pelvic injuries. This flap is reportedly more versatile than the flap based on the dorsal branch.
Flank fold flap (rear)
Based off the ventral branch of the deep circumflex iliac artery, this flap is based on the loose skin at the front of the thigh between the body wall and the stifle, associated with the flank area.
Base: The proximal area of the flank fold.
Flap: The flap is raised by grasping the loose skin of the flank skin fold and starting the incision distally. The incision is extended dorsally into the flank exposing the proximal thigh. This incision frees the flap flank fold but must be created to permit a tension‐free closure over the cranial portion of the thigh.
The flap can be rotated ventrally to close wounds in the inguinal area with a bridging incision.
This flap is useful for ventral abdominal and inguinal wounds. It is especially useful when injury or trauma may have rendered the caudal superficial epigastric flap unreliable.
Omocervical flap
The omocervical artery emerges cranial to the scapula and gives off the superficial cervical branch that supports this flap.
Creation of an “inverted‐L” shape is possible with this flap.
Base: Level of the superficial scapular lymph node with the central axis of the flap running parallel to the cranial edge of the scapula.
Caudal border: An incision along the scapular spine.
Cranial border: A parallel incision equidistance to the measured distance between the central axis and the caudal border (scapular spine).
Flap length: The location of the dorsal connecting incision is determined by the desired length of the flap. This flap is reportedly supported as far as the scapulohumeral joint on the opposite side.
Can be used for defects of the head, neck, face, ear, shoulder, and axilla.
Wound Drainage
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