Axial pattern flap based on a cutaneous branch of the facial artery in cats

Objective: To describe the cutaneous portion of the facial artery in cats and an axial pattern flap based on a branch of this artery. Study Design: Ex vivo study. Sample Population: Cat cadavers (n=12). Methods: The common carotid artery was identified, cannulated, and infused with methylene blue to assist in the identification of the facial artery, which was subsequently cannulated and selectively infused with methylene blue. The main trunk of the artery and its branches were dissected. The extent of blue coloration of the skin was evaluated on the contralateral side of the same specimen after infusing methylene blue into the facial artery. In 4 specimens, the flap was raised along previously defined borders and adequacy of perfusion was evaluated. Results: The area of skin perfused by the facial artery extended from the lower eyelid dorsally, to the angularis oris cranially, and the wing of the atlas caudally. Borders of the skin flap were defined on the basis of the anatomic dissection and skin coloration after selective infusion of the facial artery with methylene blue. A skin flap of 6 cm × 3.4 cm, based on the first caudally directed cutaneous branch of the facial artery was shown to be well perfused. The viability of this flap was confirmed in a clinical case. Conclusion: The facial artery flap is useful for repair of skin defects of the head in cats.     

Angularis oris axial pattern buccal flap for reconstruction of recurrent fistulae of the palate

OBJECTIVE: To describe the use of an axial pattern flap based on the angularis oris artery and vein for reconstruction of palate defects. STUDY DESIGN: Clinical case report ANIMALS: Two dogs with recurrent oronasal fistulae. METHODS: Oronasal fistulae previously treated by buccal mucosal random pattern flaps that subsequently dehisced were repaired using an angularis oris-based buccal tissue axial pattern flap. This flap was developed by full thickness incision of the cheek tissue, excluding the skin, about the angularis oris vascular pedicle resulting in a vascularized flap covered by oral mucosa on one side. RESULTS: In one dog, the repair was intact and healed 6 months after surgery. In the second dog with a fistula that resulted because of radiation necrosis, approximately 95% of the defect healed with a small (<1.0 cm(2)) area of dehiscence. Repair of this persistent fistula with a random pattern buccal flap failed and this small fistula remained with minimal clinical signs. CONCLUSION: An axial pattern flap based on the angularis oris artery and vein can be used to repair difficult or recurrent palate defects. CLINICAL RELEVANCE: Angularis oris axial pattern flaps provide an additional effective option for repair of defects in the hard and soft palate to the distal gingival margin of the canine tooth or beyond, depending on skull conformation. Advantages of this flap include its highly vascular and robust character, high degree of mobility and a surface of tough buccal mucosa.     

Direct cutaneous arterial supply to the tail in dogs.

Cutaneous arterial blood supply to the tail was evaluated in 12 dogs. Subtraction radiography of internal iliac artery and distal aorta angiography in 3 of these dogs was used to determine arterial blood supply to the tail from the median sacral and lateral caudal arteries. Dissection of the tail in 8 canine cadavers revealed bilateral subcutaneous location of lateral caudal arteries following tail amputation. An axial pattern flap based on the lateral caudal arteries contributed to the reconstruction of a large caudodorsal cutaneous defect in a dog. An axial pattern flap based on the lateral caudal arteries following tail amputation may be indicated to aid reconstruction of large caudodorsal cutaneous defects of the trunk in dogs.     

A Comparison of the Cutaneous Trunci Myocutaneous Flap and Latissimus Dorsi Myocutaneous Flap in the Dog

Latissimus dorsi and cutaneous trunci myocutaneous flaps of equal dimension and location were randomly elevated on opposite sides of the thorax in 10 dogs (group 1) and resutured to their respective bed. The procedure was repeated in four additional dogs (group 2); however, the short perforating branches of the thoracodorsal artery and vein were divided at the base of each cutaneous trunci myocutaneous flap, whereas the cutaneous pedicle and underlying cutaneous trunci muscle were divided in the latissimus dorsi myocutaneous flaps to determine subsequent skin survivability and the major source of circulation of each myocutaneous flap. There was little difference in the percentage of skin survival between the latissimus dorsi and cutaneous trunci myocutaneous flaps in group 1 dogs. Circulation to the "skin island" of group 2 latissimus dorsi myocutaneous flaps originated from intramuscular anastomotic connections between the major branch of the thoracodorsal artery entering the latissimus dorsi muscle and the proximal lateral intercostal arteries perforating the muscle. Ligation of the short perforating branches of the thoracodorsal artery resulted in partial skin necrosis in all group 2 cutaneous trunci myocutaneous flaps. Results from this study indicate that it is unnecessary to elevate the latissimus dorsi muscle for major skin flap elevation and survival. The thicker latissimus dorsi myocutaneous flap is more difficult to develop surgically and appears to have no clinical major advantage over the more mobile cutaneous trunci myocutaneous flap or the adjacent thoracodorsal axial pattern flap for closure of large skin defects within the radius of flap rotation.     

Axial Pattern Flap Based on the Genicular Branch of the Saphenous Artery in the Dog

Axial pattern flaps based upon the genicular branch of the saphenous artery and medial saphenous vein were developed in eight dogs. On one hind limb of each dog, the experimental flap was raised and immediately transferred to a cutaneous defect created over the lateral aspect of the lower limb distal to the stifle. A control flap was elevated and transferred on the opposite hind limb with the genicular branches of the saphenous artery and vein ligated and divided at the base of the flap. Eighty-nine per cent of the length of the flap survived in those flaps in which the genicular vessels were left intact, whereas only 54% of the flap's length survived in the control flaps. Postoperatively, all dogs were bearing weight on the limbs normally. The genicular axial pattern flap may have special clinical application in cases of cutaneous defects involving the lateral aspect of the tibia.     

The Medial Saphenous Fasciocutaneous Free Flap in Dogs

The purpose of this study was to identify the angiosome of the medial saphenous artery and vein and to evaluate the use of this cutaneous angiosome as a free skin flap in the dog. In phase 1 of this study, selective angiography of the medial saphenous artery performed in six canine cadavers showed that the skin covering the entire medial femorotibial area, the distal half of the caudal head of the sartorius muscle, and the gracilis muscle were perfused by the medial saphenous artery. In phase 2, a medial saphenous fasciocutaneous island flap was raised and sutured back to the skin edges of the donor wound in three dogs. One hundred percent survival of all of the flaps occurred. In phase 3, a medial saphenous fasciocutaneous microvascular free flap was transferred to a wound that was created over the dorsal metacarpal (n = 3) or metatarsal region (n = 3). The mean length ± SD of the medial saphenous vascular pedicle was 80 ± 13 mm (n = 5); the mean diameter ± SD of the medial saphenous artery was 2.8 ± 0.2 mm (n = 5) and the mean diameter ± SD of the medial saphenous vein was 4.2 ± 0.2 mm (n = 5). One hundred percent of all flaps survived (n = 6). Selective angiography of the distal cranial tibial artery (metatarsal wounds, n = 3) and the median artery (metacarpal wound, n = 3) was performed 3 weeks after surgery. All of the vascular anastomoses were patent and neovascularization of the wound beds was present. This free flap was found to be acceptable for cosmetic reconstruction of wounds located on the distal extremity.     

Deep circumflex iliac cutaneous free flap in cats

OBJECTIVE: To develop and assess the survival of a microvascular cutaneous free flap based on the ventral branch of the deep circumflex iliac (DCI) artery and vein in cats. STUDY DESIGN: Experimental study. ANIMALS: Phase 1: 6 feline cadavers; Phase 2: 2 adult cats; Phase 3: 10 adult cats. METHODS: Phase 1: Selective angiographic study of the deep circumflex iliac artery was completed in 6 feline cadavers. After injection of the DCI artery with barium, high-detail radiographs were made of skin flaps harvested from the lateral flank and thigh region. The extent of the cutaneous angiosome was mapped with regard to the underlying anatomical landmarks. Phase 2: An island flap based on anatomic boundaries of the DCI angiosome derived from phase 1 of the study was elevated in 2 cats. Flaps were observed for 3 weeks for survival. Phase 3: Free skin flaps based on the DCI vessels were harvested in 10 cats and transferred to the dorsal interscapular region. Flaps were evaluated for 2 weeks for survival. Tissue samples were collected for histopathology, and angiograms of the flaps were completed. RESULTS: Phase 1: Angiograms revealed a large primary cutaneous angiosome of the DCI artery located over the lateral femoral region, which extended from the iliac crest to the level of the patella. Phase 2: All island flaps survived for 3 weeks. Phase 3: Six free flaps survived for 2 weeks, and 4 flaps failed completely. Failure of 1 flap occurred because of avulsion of the venous and arterial anastomosis postoperatively. Another cat had intraoperative hemorrhage, which resulted in anemia and hypovolemia and likely caused the flap to fail. The other 2 flaps that failed had poor perfusion intraoperatively and had the longest ischemia times. CONCLUSIONS: The cutaneous DCI free flap in cats may be clinically useful in reconstruction of large cutaneous wounds. The length of ischemia time for successful cutaneous free flap transfer in the cat may be shorter than in other species. CLINICAL RELEVANCE: Large wounds created by trauma or oncologic ablative surgery in cats could be reconstructed with cutaneous microvascular free flap. Additional studies assessing the critical ischemia time of cutaneous flaps in cats and evaluating the use of this flap clinically are needed.     

Myoperitoneal Microvascular Free Flaps in Dogs: An Anatomical Study and a Clinical Case Report

The purpose of the anatomical study was to identify potential myoperitoneal microvascular free flaps, in dogs, that are based on a single artery and vein. The angiosomes of the right deep circumflex iliac artery and left phrenicoabdominal (cranial abdominal) artery were evaluated in six medium-sized canine cadavers. The right deep circumflex iliac artery and left phrenicoabdominal (cranial abdominal) artery were injected with a mixture of barium and latex (equal parts). The entire right and left transversus abdominis muscles were dissected from the abdominal wall and radiographed. The angiograms of the deep circumflex iliac artery showed poor arborization of the vessels within the transversus abdominis muscle in all six cadavers. The angiograms of the phrenicoabdominal (cranial abdominal) artery showed consistent filling of the vascular bed of the cranial half of the transversus abdominis muscle flap in all six dogs. The vascular pedicle lengths and the diameter of the arteries and veins of both the deep circumflex iliac and phrenicoabdominal (cranial abdominal) myoperitoneal free flaps were found to be acceptable for microvascular anastomosis. The deep circumflex iliac flap was unacceptable because of inadequate vascular perfusion. The cranial abdominal artery had a consistent, large branch that supplied the cranial half of the transversus abdominis muscle, thereby making a myoperitoneal flap supplied by this vessel a potentially useful free flap. An 8-year-old male, neutered, mixed-breed dog was evaluated for possible repair of a large defect of the hard palate. Previous operations, using local tissue flaps, had been unsuccessful. A myoperitoneal free flap, based on the right cranial abdominal artery, and consisting of the cranial portion of the transversus abdominis muscle, was used successfully to reconstruct the hard palate. Migrating epithelium from the edges of the wound covered the myoperitoneal flap by 10 weeks after surgery. Therefore, the cranial abdominal myoperitoneal free flap can be considered for reconstruction of intra-oral defects that cannot be repaired using conventional local flap techniques.     

Complications and outcome after thoracodorsal axial pattern flap reconstruction of forelimb skin defects in 10 dogs, 1989-2001

OBJECTIVE: To determine (1) the frequency and extent of complications associated with thoracodorsal axial pattern flap reconstruction of forelimb skin defects in dogs and (2) outcome after treatment of such complications. STUDY DESIGN: Retrospective clinical study. SAMPLE POPULATION: Ten dogs. METHODS: Medical records for 10 dogs that had a thoracodorsal axial pattern skin flap reconstruction of a forelimb skin defect were reviewed. RESULTS: Three dogs had complete flap survival. Partial necrosis of the distal flap, ranging from an estimated 2% to 53% (mean, 21%) of the flap surface area, occurred in 7 dogs. Six dogs required surgical management of the skin necrosis, resulting in successful resolution in 5 dogs, whereas, in 2 dogs, the wound healed by second intention. Positive bacterial cultures were obtained from 3 dogs with distal flap necrosis. Seroma formation was noted in 2 dogs; the entire flap survived in 1 dog, whereas the second dog developed distal flap necrosis. Edema and bruising of the distal portion of the flap were noted in 8 dogs; distal flap necrosis subsequently developed in 7 dogs. Partial incisional dehiscence, which healed by second intention, occurred in 2 dogs. Of 6 owners available for follow-up, all were satisfied with the functional outcome, but 1 owner was not satisfied with the cosmetic appearance. CONCLUSIONS: Partial flap necrosis was a frequent complication of thoracodorsal axial pattern flap reconstruction of forelimb skin defects and required additional wound care or surgical intervention to achieve healing. CLINICAL RELEVANCE: Thoracodorsal axial pattern flaps can provide full-thickness skin coverage of extensive skin defects of the forelimb, but owners should be aware of the likelihood of local wound complications.     

The Anatomic Basis for a Trapezius Muscle Flap in Dogs

The anatomy of the cervical part of the trapezius muscle and its dominant vascular supply, the prescapular branch of the superficial cervical artery, was studied by dissection and selective angiography of 16 canine cadavers. The prescapular branch of the superficial cervical artery supplies blood to the skin of the caudal half of the neck and the cervical part of the trapezius muscle and is a minor contributor to other muscles of the neck. In these dogs, the mean length of the vascular pedicles was 4.4 cm and the mean diameter was 1.0 mm. With this information, it is possible to design a broad musculocutaneous flap suitable for reconstructive microsurgery in dogs. The potential for successful incorporation of the scapular spine in such a flap remains uncertain.     

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.     

Free Microvascular Transplantation of the Trapezius Musculocutaneous Flap in Dogs

A musculocutaneous flap based on the prescapular branch of the superficial cervical artery and including the cervical part of the trapezius muscle and overlying skin was transplanted over a defect created on the medial side of the contralateral tibia in four dogs by using microvascular technique. The donor and recipient sites in three dogs were examined clinically for 21 days, after which they were examined angiographically and histologically. All dogs were free of lameness by hour 48. Seromas formed at the donor site between days 7 and 15. One vascular pedicle was traumatized at hour 40, and the dog was euthanatized. Three flaps survived with minimal necrosis. Edema of the flaps was severe from days 5 to 11. Angiograms showed complete perfusion of the flaps, and survival was confirmed histologically. Esthetic appearance and function were good in one dog at month 7.     

Abdominal Wall Reconstruction with a Vascular External Abdominal Oblique Myofascial Flap

A myofascial island flap for abdominal wall reconstruction was based on the lumbar component of the external abdominal oblique muscle and supplied by a major neurovascular pedicle consisting of branches of the cranial abdominal artery, cranial hypogastric nerve, and a satellite vein. The flap was elevated and sutured into a 10 cm x 10 cm body wall defect in five dogs. The dogs were observed for 26 to 28 days. Abdominal wall contour and function were preserved. All dogs developed seromas, two of which became infected. One dog developed a hernia at the dorsal margin of the flap, which was repaired. At necropsy, there was no evidence of dehiscence in any of the dogs. Loose adhesions of omentum to the inner surface of the flap occurred in four dogs. Results of histologic examination confirmed the clinical impression of flap viability. The myofascial island flap has a wide range of mobility over the ventral and caudal areas of the abdomen and lateral thoracic wall. It has potential clinical use for reconstruction of defects within its arc of rotation.     

Rapid Tissue Expansion for the Development of Rotational Skin Flaps in the Distal Portion of the Hindlimb of Dogs: An Experimental Study

In phase I, tissue expanders were implanted subcutaneously over the lateral crural region of four dogs. The expanders were inflated daily to maintain a constant intraluminal pressure for 7 days. All animals tolerated the pressurized expanders well. Some animal patient discomfort was associated with repeated injections into the subcutaneous filling port. One dog developed a limited area of tissue loss and exposure of the expander. Tissue response to the expanders included epidermal hyperplasia, dermal collagen compression with early fibroplasia, and subcutaneous granulation tissue formation adjacent to the expander pocket. In phase II, a second group of four dogs underwent rapid skin expansion over 7 days. The pressure applied to the expanding skin was determined daily and adjusted to approximate the value reported for capillary pressure in the dog. Tissue discoloration occurred in two dogs, suggestive of impaired circulation. Skin flaps were developed from expanded skin and rotated over the talocrural region. Wound dehiscence occurred along the distal flap margin in three phase II dogs. These wounds healed by second intention. Branches of the caudal saphenous artery were identified, using angiography, as the primary blood supply to the skin flaps.     

Surgical treatment of canine nasal aspergillosis by rhinotomy combined with enilconazole infusion and oral itraconazole

OBJECTIVES: To evaluate the effectiveness of rhinotomy and surgical debridement associated with topical administration of 2 per cent enilconazole and oral itraconazole in dogs with severe or recurrent sinonasal aspergillosis. METHODS: A standard rhinotomy was performed on seven dogs. In the initial study, the bone flap was left attached cranially and replaced at the end of the procedure. In the main study group, the bone flap was discarded. Nasal passages were debrided and irrigated with enilconazole solution for one hour. Oral itraconazole was administered to four dogs for one month postoperatively. Follow-up rhinoscopy was performed in all dogs. RESULTS: All three dogs in the initial study had recurrence of the disease and two dogs had a second surgery to remove the flap. The main study group included four dogs in which the flap was initially removed, and the two dogs from the initial study that required a second surgery. At follow-up rhinoscopy, five dogs were free of aspergillus but had bacterial or inflammatory rhinitis and one dog had a small aspergilloma but was subsequently asymptomatic. Telephone follow-up revealed that four dogs were asymptomatic, one dog had intermittent sneezing and serous nasal discharge, and one dog had intermittent epistaxis. CLINICAL SIGNIFICANCE: Rhinotomy with removal of the flap combined with one-hour infusion of 2 per cent enilconazole and oral itraconazole resulted in satisfactory outcome in dogs with severe or recurrent aspergillosis.     

Evaluation of primary critical ischemia time for the deep circumflex iliac cutaneous flap in cats

OBJECTIVE: To evaluate the primary critical ischemia time for the deep circumflex iliac (DCI) cutaneous flap in cats. STUDY DESIGN: In vivo model. ANIMALS: Thirteen young adult female cats. METHODS: An island skin flap was created on the right side of each cat based on the angiosome of the ventral branches of the DCI vessels. The cats were randomly assigned to a flap ischemia time ranging from 1 to 3 hours in 10-minute intervals. Microvascular clamps were used to occlude the artery and vein for the designated time. Flaps were sutured into position after the ischemic period. On day 3, fluorescein dye was administered and the flaps were evaluated under ultraviolet light to assess percent area of perfusion. On days 7 and 14, the percent area of survival was determined for each flap based on cutaneous morphometry. RESULTS: All flaps had 100 percent area of survival throughout the study. On day 3, all flaps fluoresced uniformly compared with the surrounding skin. On days 7 and 14, all flaps were uniformly viable as confirmed by skin color, consistency, bleeding, and hair re-growth. CONCLUSION: The DCI cutaneous flap in cats can withstand up to 3 hours of ischemia with predictable survival. CLINICAL RELEVANCE: In a clinical setting, high success rates can be expected with microvascular transfer of the DCI cutaneous flap in cats when the ischemia time is <3 hours and precise surgical technique is used.     

Modification of the superficial cervical axial pattern skin flap for oral reconstruction

OBJECTIVE: To describe an extended pedicle flap based on the superficial cervical artery (SCA) for closure of oral defects in dogs. STUDY DESIGN: Anatomic study; in vivo experimental study. ANIMALS: Canine cadavers (13) and 3 dogs. METHODS: The prescapular branch of the SCA was cannulated and perfused with a lead oxide gelatin mixture. The area perfused by 1 SCA was examined as was the rostral extent of the flap. Staged implantation was performed to evaluate flap performance in vivo. In stage 1, the flap was prepared for implantation into the oral cavity. In stage 2, the flap was fully developed to include the 1 degrees, 2 degrees, and partial 3 degrees angiosome of 1 SCA pedicle. The flap was transposed by a bridging incision and a parapharyngeal tunnel into the oral cavity. The flap was used to reconstruct a partial-thickness defect created in the palate. RESULTS: The territory of the contralateral SCA was captured in all cadavers. The full flap reached the level of the canine teeth in all cadavers. In live dogs, necrosis was not observed after implantation into partial-thickness defects and dehiscence was minimal. Loss of pliability secondary to de-epithelialization and staging resulted in a limitation of rostral reach of the flap. CONCLUSIONS: Whereas the flaps did not reach as far rostrally as anticipated, they survived well in the harsh oral environment. The flap may be modified to reconstruct full-thickness palatal defects. CLINICAL RELEVANCE: The extended SCA pattern flap may be adapted for closure of oral defects.     

Axial Pattern Flap Based on the Superficial Brachial Artery in the Dog

An axial pattern flap based on the superficial brachial artery and vein (brachial axial pattern flap) was developed on the forelimbs of five dogs. The flap was immediately transferred to a distal cutaneous defect created on the antebrachium of that limb. A control flap was elevated on the opposite limb and transferred to a similar distal site after ligation of the superficial brachial artery and vein at the base of the flap. Mean brachial axial pattern flap survival (98%) was significantly more than mean control flap survival (77%) (p less than 0.05). Results of this study suggest that the brachial axial pattern flap has potential application for closure of major cutaneous defects involving the canine antebrachium above the carpus.     

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.