Axial pattern flap based on the caudal auricular artery in dogs

An axial pattern flap that was based on the sternocleidomastoideus branches of the caudal auricular artery and vein was developed. Control flaps, which included ligation and division of the caudal auricular artery and vein, were similarly developed on the contralateral aspect of the neck. Mean survival of caudal auricular artery axial pattern flaps (85.2%), compared with control flaps (63.9%), was significantly different (P less than 0.05). On the basis of results of this study, an axial pattern flap based on the sternocleidomastoideus branches of the caudal auricular artery and vein may be a source of skin for reconstructive procedures of the head and neck.     

Evaluation of the Cranial Rectus Abdominus Muscle Pedicle Flap as a Blood Supply for the Caudal Superficial Epigastric Skin Flap in Dogs

This study evaluates the cranial rectus abdominus muscle pedicle flap as the sole blood supply for the caudal superficial epigastric skin flap. This flap was composed of a cranially based rectus abdominus muscle pedicle flap that was attached to the caudal superficial epigastric island skin flap (including mammary glands 2 to 5) via the pudendoepigastric trunk. Selective angiography of the cranial epigastric artery in eight cadaver dogs proved that the arterial vasculature in the cranial rectus abdominus was contiguous with that in the caudal superficial epigastric skin flap. In the live dog study, three of six of the flaps failed because of venous insufficiency. Necrosis of mammary gland 2 occurred in two of six flaps. One of six flaps survived with the exception of the cranial most aspect of mammary gland 2. Angiography of the cranial epigastric artery proved that arterial blood supply to these flaps was intact. Histological evaluation of the failed flaps showed full-thickness necrosis of the skin and subcutaneous tissues, the presence of severe congestion, and venous thrombosis. Retrograde venous blood flow through the flap was inconsistent, and hence resulted in failure of this myocutaneous flap. Use of this flap for clinical wound reconstruction cannot be recommended.     

Skin flaps in reconstructive surgery

A skin flap (pedicle graft) is a partially detached segment of skin and subcutaneous tissue that includes a blood supply essential to its survival. As a result, skin flaps are capable of closing a variety of defects, including poorly vascularized wound beds that are incapable of maintaining free grafts. In many cases, skin flaps can bypass economically many of the potential problems associated with healing by second intention. This article presents an overview of pedicle grafts, with emphasis on the clinical use of local flap techniques.     

The Isolated Perfused Equine Skin Flap Preparation and Metabolic Parameters

A model for the study of equine cutaneous physiology, pharmacology, and toxicology was developed. Four 4 x 12 cm and twenty-one 6 x 12 cm single-pedicle axial pattern skin flaps based on the caudal superficial epigastric artery, and eight 6 x 12 cm flaps based on the saphenous artery and medial saphenous vein, were raised and sutured in a tubed configuration. On day 2, each flap was removed, the artery was cannulated, and the flap was perfused with a modified Krebs-Ringer's albumin-based medium for at least 6 hours. Flap viability was assessed by glucose use, lactate production, and histologic examination at the end of the perfusion period. The 4 x 12 cm flaps had evidence of skin necrosis, but the 6 x 12 cm flaps remained histologically viable. Results were compared to those previously reported from perfusion of porcine skin flaps based on the caudal superficial epigastric artery. While the ratios of glucose use to lactate production were similar, equine flaps used less glucose and produced less lactate per gram of tissue than similar pig flaps. Equine skin flaps perfused by saphenous vessels used more glucose and produced more lactate than flaps perfused by caudal superficial epigastric vessels. These results indicate that conclusions drawn from cutaneous physiology studies should not be extrapolated across species lines and that site-specific skin should be used for cutaneous physiology, pharmacology, and toxicology studies. The identified skin flaps may have applications in equine reconstructive surgery.     

Skin Fold Advancement Flaps for Closing Large Sternal and Inguinal Wounds in Cats and Dogs

Skin fold advancement flaps can be created from the elbow and flank folds to close large wounds in the pectoral and inguinal regions of cats and dogs, respectively. The attachments of the laterally facing (outer) and medially facing (inner) layers of the skin fold to the adjacent limb are divided to produce a U-shaped pedicle graft attached to the trunk. This mobilizes skin that can be advanced over large wounds involving the ventral chest or abdomen, or both. The use of skin fold advancement flaps enables direct closure of large skin defects without undue tension and without compromising the mobility of the adjacent limb.     

Radical Lateral Body-Wall Resection for Fibrosarcoma With Reconstruction Using Polypropylene Mesh and a Caudal Superficial Epigastric Axial Pattern Flap: A Prospective Clinical Study of the Technique and Results in 6 Cats

OBJECTIVE: To describe and evaluate a technique for radical resection of the lateral body wall for treatment of fibrosarcoma with reconstruction using polypropylene mesh and a caudal superficial epigastric axial pattern flap in cats. STUDY DESIGN: Prospective, clinical study. ANIMALS OR SAMPLE POPULATION: Six client-owned cats with fibrosarcoma. METHODS: Six cats with histologically confirmed fibrosarcoma of the lateral body wall were staged using radiography and/or computer tomography scanning. Preoperative radiotherapy was used in 3 cats. All cats had the lateral abdominal wall resected and reconstructed with polypropylene mesh. A caudal superficial epigastric flap was mobilized and rotated to close the skin deficit. The animals were evaluated after surgery for wound complications, tumor recurrence, and metastasis. Outcome was assessed by patient examination and client consultation. RESULTS: Minor dehiscence of the skin flaps occurred in 2 cats, and 1 other cat was successfully resuscitated from respiratory and cardiac arrest after surgery. All tissue specimens were tumor-free at the surgical margins. Follow-up times ranged from 12 to 21 months, with a mean time of 17.2 months. None of the cats had evidence of local tumor recurrence or metastasis; outcome was judged good to excellent in all cats. CONCLUSIONS AND CLINICAL RELEVANCE: Radical lateral body-wall resection and reconstruction is an effective technique for achieving local tumor control with acceptable patient morbidity. Further studies are needed to assess whether the technique will result in improved tumor-free intervals and survival times.     

Skin grafts

Skin grafting is a method to reconstruct the skin covering on areas of the body where there are defects and insufficient surrounding skin for advancement or for creation of flaps. Grafts are classified according to their host-donor relationship and by their thickness. Autogenous grafts, taken from one area of the body and applied to another area, are the type of graft used most often clinically. Pieces of skin are taken from one area of the body, prepared and applied over a defect that has also been properly prepared to accept the graft. The defect to which a graft is applied must be a healthy bed of granulation tissue or tissue that is vascular enough to produce a bed of granulation tissue. In its new location, the graft will develop a new blood supply and attachment to underlying tissues. This is accomplished as the graft undergoes the processes of fibrinous adherence, plasmatic imbibition, inoculation, and new vessel ingrowth. The types of grafts described in this chapter are split-thickness, full-thickness, seed, strip, and stamp grafts. Each of these graft types must be prepared using certain techniques, and each one has its inherent advantages and disadvantages. Split-thickness grafts may require considerable skill and/or expensive equipment to perform. Although they "take" better than full-thickness grafts, they are usually less cosmetically attractive. Full-thickness grafts require no special skill or expensive equipment, and their cosmetic appearance is better than that of split-thickness grafts, but they do not take as well as split-thickness grafts. Seed and strip grafts are easily accomplished and require no special instruments; however, their cosmetic appearance is not good. Stamp grafts have some of the properties associated with split-thickness grafts as well as those of seed and strip grafts, since they combine features of both.     

Axial pattern flap based on the lateral caudal arteries of the tail in the dog: an experimental study

OBJECTIVE: To determine applicability and size limits of an axial pattern flap based on the lateral caudal arteries in dogs to reconstruct caudodorsal trunk skin defects. STUDY DESIGN: Experimental study. ANIMALS: Ten mature, mixed breed dogs. METHODS: The lateral caudal vessels of the tail were incorporated in the flaps of the treatment group (n=5) and were ligated in the control group (n=5). Flaps were rotated and placed into experimentally created caudodorsal skin defects on the trunk. The length and area of tissue that remained viable in each flap were determined. RESULTS: Mean (+/-SD) survival area (222.8+/-32.9 cm2) and length (25.1+/-4.5 cm) of vascularized flaps were significantly greater (P<.05) compared with control flaps (94.9+/-13.4 cm2 and 14.61+/-4.7 cm). Necrosis occurred in all control flaps, resulting in lower percentage flap area (48.8%) and length (47.1%) survival compared with vascularized flaps (78.1%, 77.5%). CONCLUSIONS: Axial pattern flap based on lateral caudal arteries of the tail was successfully elevated and transferred in a single procedure, with 78% survival for closure of large experimentally created caudodorsal trunk defects in dogs. CLINICAL RELEVANCE: Large cutaneous defects of the caudodorsal trunk area in dog could be reconstructed with tail axial pattern flap. Limitations in terms of size and changes in animal appearance have to be considered before flap elevation.     

Controlled Tissue Expansion in the Distal Extremities of Dogs

Controlled tissue expansion using a 100 cc rectangular silicone elastomer expander was performed in the mid-antebrachium and mid-crus of eight adult mixed-breed dogs. Two expander inflation schedules were followed. Group 1 dogs (n = 4) underwent expander inflation using 10 cc sterile saline every other day, and group 2 dogs (n = 4) underwent expander inflation using 15 cc sterile saline every other day until the nominal volume (100 cc) was attained. Significant mean postexpansion increases in skin surface area of 94.1 cm² (35.9%) and 108.9 cm² (37.3%) were measured in the antebrachium and crus, respectively (p < .05). In a second procedure, the expanders were removed and skin flaps were developed from the redundant tissue generated during the expansion process. Single pedicle advancement flaps and transposition flaps were used to cover surgically created defects measuring 5 times 10 cm in the antebrachium and cms. Single pedicle advancement flaps consistently measured 10 × 10 cm and could be advanced to cover defects involving one third of the mid-antebrachial or mid-crural circumference. Transposition flaps were rotated up to 170 and the donor site defects were easily closed under minimal or no tension. Complications included an abscess in one dog and seroma formation in four dogs. Differences in success or complication rates between group 1 dogs and group 2 dogs were not observed; an accelerated inflation schedule using 15 cc sterile saline every other day was recommended.     

Transfer of Free Vascular Cutaneous Flaps by Microvascular Anastomosis Results in Six Dogs

Skin defects on the distal extremities of six dogs were reconstructed with free vascular cutaneous transfers by microvascular anastomosis. The donor flaps were based on the superficial cervical artery and vein. In five of the dogs, bone was exposed and skin was lost from half of the circumference of the limb. Two had infected fractures with sequestra and three had acute shearing injuries. The sixth dog had sensory denervation of the left antebrachium and a carpal acral lick granuloma. Before surgery, the patency of potential recipient vessels was confirmed with arteriography in five dogs and an ultrasonic doppler in one dog. Microvascular technique was used to reestablish circulation to the flaps after they were transferred to the recipient site. Total ischemic time of the flaps averaged 100 minutes. All flaps survived. Successful reconstruction of the cutaneous defects was achieved in these six cases.     

Caudal Superficial Epigastric Arterial Pedicle Grafts in the Dog

A direct cutaneous arterial pedicle graft (axial pattern flap) was created from the mammary chain including glands 2 through 5 using the caudal superficial epigastric artery and vein in 4 male and 4 female dogs. All grafts survived immediate development and transfer to the recipient site which was either the flank, inner thigh, or lower limb region. A high per cent survivability rate can be expected if precautions are taken. This procedure has special application for reconstruction of extensive flank, inner thigh and inguinal skin losses.     

Pedicle skin flaps in ponies: viable length is related to flap width.

The relationship between pedicle flap width and viable length was characterised for skin flaps of the flank in ponies. Four dorsally based, pedicle type skin flaps of 20 cm in length and 3, 6, 9 or 12 cm in width were created in a random sequence on one flank in each of 10 ponies. Flap survival length was assessed by skin texture and appearance, depilation of hair and wound healing at 14 days after surgery. There was considerable variation between animals in the viable length of flaps of the same width; however, a significant difference in the viable length of flaps of different widths was detected (P = 0.002). The viable length of the 3 cm flaps was significantly different from that of the 12 cm flaps (9.69 +/- 1.1 cm vs 12.97 +/- 1.0 cm, mean +/- se P less than 0.05). There was a positive correlation between flap width and viable length (r2 = 0.141, P = 0.017). There was no effect of flap order (cranial to caudal positioning relative to the other flaps) on viable length (P = 0.286). The results of this study demonstrate a significant relationship between flap width and viable length, confirming a previously unsupported assumption that flap width and viable length are related. These findings suggest that the clinician should employ broad pedicles when using local flaps to reconstruct skin defects on the flank of the horse.     

Skin-fold advancement flaps for closing large proximal limb and trunk defects in dogs and cats

OBJECTIVE: To describe the use of skin-fold advancement flaps for covering large skin defects in dogs and cats. STUDY DESIGN: Clinical study. ANIMALS: Eight client-owned animals: 6 dogs and 2 cats. METHODS: Six dogs and 2 cats underwent reconstruction of soft-tissue wounds resulting from traumatic, neoplastic, or infectious lesions. Skin-fold flaps were created by division of the medial and lateral attachment to the proximal limb or the dorsal and ventral attachment to the trunk, enabling closure of adjacent defects on the trunk or proximal limb, respectively. RESULTS: Skin-fold flaps proved effective for closing defects in all animals. Necrosis of a portion of the flap occurred in 2 dogs due to technical errors, but the resultant defects remained amenable to primary closure. All wounds ultimately healed primarily, without major complications. CONCLUSION AND CLINICAL RELEVANCE: The skin-fold advancement flap is a versatile technique that lends itself to use in a variety of locations, depending on which attachments are divided. The clinical results are comparable with those reported for axial pattern and subdermal plexus flaps.     

Distal limb and paw injuries.

Distal limb reconstruction is complicated by the paucity of local tissues and the frequent association of orthopedic injury with cutaneous loss. Second-intention healing or skin stretching techniques are used for wounds involving less than a 30% circumference of the limb. Skin grafts are recommended for reconstruction of larger superficial wounds after establishing a bed of granulation tissue or for immediate reconstruction of clean wounds overlying healthy muscle. Wounds complicated by orthopedic injury benefit from early reconstruction using vascularized tis-sue. Weight-bearing surface reconstruction and management of partial amputation injuries are functionally difficult because of the environmental stress placed on the paw pads. Paw pad grafts, paw pad transposition techniques, centralization of digits, and microvascular free tissue trans-fer of paw pads can be considered for weight-bearing surface reconstruction. Definitive guidelines describing when each of these techniques should be used have not been established.     

Thoracodorsal and Caudal Superficial Epigastric Axial Pattern Skin Flaps in Cats

Nonselective angiography, selective angiography, and gross dissection of 15 cadavers were performed to delineate direct cutaneous arteries in the cat. The omocervical, deep circumflex iliac, thoracodorsal, and caudal superficial epigastric arteries were identified by nonselective angiography. Selective angiography and gross dissection allowed assessment of the origin and vascular territories of the thoracodorsal and caudal superficial epigastric arteries. Orthotopic and heterotopic transfers of thoracodorsal and caudal superficial epigastric island flaps were performed on eight cats. All flaps were successful although areas of necrosis at the caudodistal tips were evident in most of the thoracodorsal flaps. The rotated thoracodorsal flaps extended to the carpi. Caudal superficial epigastric flaps enabled coverage to the metatarsus. Seroma formation and partial dehiscence were minor complications.     

Assessment of a caudal external thoracic artery axial pattern flap for treatment of sternal cutaneous wounds in birds

OBJECTIVE: To assess the use of a caudal external thoracic artery axial pattern flap to treat sternal cutaneous wounds in birds. ANIMALS: 16 adult Japanese quail. PROCEDURE: A cutaneous defect in the region of the mid-sternum was surgically created in all quail. In 6 quail (group I), an axial pattern flap was created from the skin of the lateral aspect of the thorax and advanced over the sternal defect. In 8 quail (group II), a flap was similarly created and advanced but the flap vasculature was ligated. All quail were euthanatized at 14 days after surgery and had necropsies performed. Sections of the flap and the surrounding tissue were examined histologically to assess flap viability. RESULTS: All axial pattern flaps in group-I quail had 100% survival. In group II, mean percentage area of flap survival was 62.5%; mean area of necrosis and dermal fibrosis of flaps were significantly greater than that detected in group I. In flaps of group-II quail, neovascularization in the deep dermis and profound necrosis of the vascular plexus in the superficial dermis were observed. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that the caudal external thoracic artery axial pattern flap could be used successfully in the treatment of surgically created sternal cutaneous defects in quail with no signs of tissue necrosis or adverse effects overall. Use of this technique to treat self-mutilation syndromes or application after surgical debulking of tumors or other masses might be beneficial in many avian species.     

Development of surgical techniques for preparation of in vitro-isolated perfused porcine skin flaps for percutaneous absorption studies

We developed a single-pedicle, axial pattern tubed skin flap that could be transferred to an in vitro perfusion apparatus. On the basis of results of prosections, angiography, contact radiography, and surviving-length studies, it was concluded that a single-pedicle, axial pattern skin flap measuring 4 cm x 12 cm incorporating the caudal superficial epigastric artery would survive to its entire length. Subsequently, a surgical (stage 1) procedure was developed for the routine preparation of single-pedicle, axial pattern tubed skin flaps. Healing after the stage-1 procedure was evaluated by visual inspection and fluorescein angiography. Stage-1 procedures were performed successfully 149 of 160 (93%) times. A second surgical (stage 2) procedure was developed for routine cannulation of the caudal superficial epigastric artery and harvest of the tubed skin flap. Stage-2 procedures were performed successfully 136 of 144 (94%) times.     

Repair of sinocutaneous fistulae in two horses

Chronic facial defects extending into the sinuses of two mares were repaired using periosteal flaps. Partial osseous bridging was established over the defects following repair. Previous attempts to close the defects with skin alone had failed. A periosteal flap is a simple surgical technique that provides the foundations for successful repair, despite the chronicity of some fistulae.     

Clinical evaluation of caudal superficial epigastric axial pattern flap reconstruction of skin defects in 10 dogs (1989-2001)

Ten dogs with caudal superficial epigastric axial pattern flap reconstruction of extensive skin defects were reviewed. Nine dogs had complete survival of the flap. In one dog, a small area of necrosis occurred near the flap tip. Other complications included seroma formation (n=3), partial incisional dehiscence (n=3), flap edema (n=9), and bruising (n=7). Use of the caudal superficial epigastric axial pattern flap provided full-thickness skin coverage of extensive skin defects of the rear limb and inguinal region, with relatively minor complications that were amenable to conservative management.