Use of an axial pattern skin flap based on the cranial cutaneous branch of the saphenous artery in the dog.

OBJECTIVE: To report the use of an axial pattern flap based on the cranial cutaneous branch of the saphenous artery to close a skin defect left on the medial crus after mast cell tumour removal. CASE REPORT: A seven-year-old, 32.41 kg, neutered male mixed-breed dog had a mast cell tumour incompletely excised from the left medial crus. The resulting 6 cm linear scar was excised with 2 cm wide margins and one fascial plane for deep margins. An axial pattern skin flap incorporating the cranial cutaneous branch of the saphenous artery was used to close the resultant skin defect. RESULTS: The histopathology report documented clean margins and the flap survived completely. A seroma developed postoperatively, however it resolved without treatment. CLINICAL SIGNIFICANCE: An axial pattern skin flap based on the cranial cutaneous branch of the saphenous artery is a viable option for closing medial crus skin defects in the dog.

Use of the angularis oris cutaneous flap for repair of a rostral mandibular skin defect in a cat.

The angularis oris axial pattern flap is based on the blood supply of the angularis oris artery and vein. While the use of this flap for repair of canine facial wounds is well documented, this technique has not been reported in the cat. This case report presents the reconstruction of a large ventral chin and rostral lip wound with the use of this flap. Complete survival of this flap was observed in this patient.

Effects of epidural anesthesia on microcirculatory blood flow in free medial saphenous fasciocutaneous flaps in dogs.

OBJECTIVE: To assess the effects of epidural anesthesia using lidocaine on microcirculatory blood flow, volume, and velocity in free fasciocutaneous flaps in dogs. Study Design-In vivo experimental investigation. Animal Population-Ten adult dogs weighing 20 to 25 kg. METHODS: A medial saphenous fasciocutaneous free flap was removed and an orthotopic transfer was performed by anastomosing the primary flap vessels back to the medial saphenous vessels. Blood flow (mL(LD)/min/100 g), volume (%volume or tissue hematocrit) and velocity (mm/s) in the flap were recorded throughout the procedure. After epidural anesthesia, blood flow, volume, and velocity values were again recorded. RESULTS: Microcirculatory blood flow, volume, and velocity, as measured by a laser-Doppler flowmeter, failed to reveal any significant changes over time. Immediately after epidural anesthesia, mean arterial pressure was significantly reduced and remained depressed throughout the experimental procedure. CONCLUSIONS: Epidural anesthesia combined with general anesthesia does not improve microcirculatory flow in free flaps in the pelvic limbs of dogs. No significant change in blood flow to the medial saphenous fasciocutaneous free flap occurred after division and anastomosis of the vascular pedicle. CLINICAL RELEVANCE: We recommend that epidural anesthesia with 2% lidocaine be used with caution in dogs undergoing microvascular free-flap transfer.

Testosterone-producing thecoma in a female cat.

Virilizing features in a six-year-old, spayed female, domestic shorthair cat resolved following surgical removal of a mass at the left ovarian stump. Serum testosterone concentration before surgery was elevated. Clinical signs resolved and testosterone concentration normalized after removal of the tumor. A testosterone-producing thecoma was found on histopathology. This report presents the case report and literature review of thecomas.

Evaluation of a free vascularized medial tibial bone graft in dogs.

OBJECTIVE: To develop a free vascularized tibial bone graft based on the periosteal saphenous blood supply. STUDY DESIGN: Preliminary anatomic study of medial tibial blood supply. In vivo comparison of a vascularized and avascular tibial bone graft. ANIMALS: Nine canine cadavers; 14 healthy adult dogs that weighed 25 to 32 kg. METHODS: An anatomic study of the vascular supply of the medial aspect of the tibia was performed using the Spalteholz technique. A bone graft consisting of the medial aspect of the tibia was transferred to a mandibular defect as a vascularized graft in 7 dogs and as an avascular graft in 7 dogs. Bone scans were performed to evaluate graft perfusion. Radiographic evaluation of the mandibles and tibias was performed. The dogs were killed after 60 days, five mandibles from each group were examined histologically, and two from each group were evaluated using the Spalteholz technique. RESULTS: The saphenous vascular pedicle provides vascular perfusion to the medial tibial cortex. Bone scans and radiographic evaluations were consistent with viable bone in the vascularized grafts, and nonviable bone in the avascular grafts. Histological examination revealed live, healing bone in vascular grafts and necrotic bone in avascular grafts. Spalteholz evaluation revealed many small arborizing vessels in the vascular grafts and no organized vasculature in the avascular grafts. CONCLUSIONS: The vascularized medial tibial cortical bone graft survived and proceeded to bony union in the mandibular body defect more readily than the avascular graft in this experimental model. CLINICAL RELEVANCE: A vascularized medial tibial bone graft is a suitable free graft for use in reconstructing bone defects in dogs.

Microvascular free tissue transfer: results in 57 consecutive cases.

OBJECTIVE: To evaluate the outcomes and complications in a consecutive series of animals undergoing microvascular reconstructive procedures at two veterinary institutions. STUDY DESIGN: Retrospective study. ANIMALS OR SAMPLE POPULATION: A total of 44 client-owned dogs and one red-necked wallaby. METHODS: The medical records of all animals undergoing reconstructive microsurgical procedures at the Western College of Veterinary Medicine and Michigan State University were reviewed. Microvascular flap survival and related complications were described. Statistical analysis was performed to determine the significance of relationships between operative factors and outcome. RESULTS: A total of 57 microvascular procedures were performed on 55 animals. Reconstruction was required after trauma in 42 animals, after ablative cancer surgery in 11 animals and for correction of congenital tissue aplasia in I animal. Donor tissues included the superficial cervical cutaneous, medial saphenous fasciocutaneous or musculofasciocutaneous, caudal superficial epigastric cutaneous, trapezius muscle or musculocutaneous, caudal sartorius muscle, latissimus dorsi muscle or musculocutaneous, cranial abdominal myoperitoneal, carpal footpad, digital footpad, and vascularized ulnar bone flaps. A total of 53 of 57 flaps (93%) survived. There was a significant relationship between flap failure and level of assistant surgeon experience (P < .05). Latissimus dorsi flaps were significantly more likely to fail when compared with pooled data from all other flap types (P < .01). CONCLUSIONS: The success of microvascular tissue transfer in this case series compares favorably with those reported in human reconstructive microsurgery. Both the primary and assistant surgeon should be practiced in microsurgical technique. Failure of latissimus dorsi flaps was not likely caused by an inherently deficient flap design, but was more likely attributed to the location and severity of trauma at the recipient site, the difficulty in isolating suitable recipient vessels for anastomosis or the absence of a trained assistant surgeon during these procedures. Clinical Relevance-This retrospective study documents the successful application of microvascular technique in a series of clinical cases requiring tissue reconstruction.

Splenocaval shunting for alleviation of portal hypertension in a dog: a case report.

OBJECTIVE: To describe the construction and use of a splenocaval shunt to prevent portal hypertension in a dog with iatrogenic rupture and subsequent complete occlusion of an intrahepatic portosystemic shunt (IPSS). STUDY DESIGN: Case report describing a single, client-owned animal. RESULTS: During dissection, the back wall of an IPSS was torn. Complete shunt occlusion was required to control the hemorrhage. This resulted in the development of life-threatening portal hypertension. Emergency splenocaval shunt construction reduced the portal pressure from 47 to 20 cm H2O. The dog experienced minimal postoperative complications. A second surgical procedure was performed a month later to completely ligate the splenocaval shunt. CONCLUSIONS: A splenocaval shunt can be used to divert blood from the portal to the systemic circulation to control portal hypertension. In this dog, it resulted in a successful outcome with few complications. CLINICAL RELEVANCE: The splenocaval shunt could be constructed before the dissection of a difficult IPSS if problems arise as occurred in the dog described in this report. Complete IPSS occlusion can be performed without development of portal hypertension.

Medial saphenous fasciocutaneous and myocutaneous free flap transfer in eight dogs.

Skin defects on the distal extremity (n = 7) or face (n = 1) of eight dogs were repaired using a medial saphenous fasciocutaneous or myocutaneous flap. The cause of the wounds were ablative oncological surgery (n = 4), trauma (n = 3), or radiation burn (n = 1). The flap was removed from the medial femorotibial region, and transferred to the wound bed. The vascular supply to the flap was reestablished via microvascular anastomosis of the medial saphenous vessels of the flap to recipient vessels isolated adjacent to the wound. Three flaps incorporated the distal half of the caudal head of the sartorius muscle to form a myocutaneous free flap. All flaps survived completely. The medial saphenous fasciocutaneous and myocutaneous free flaps were found to be reliable and cosmetically acceptable for repair of skin defects in dogs.

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.

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.

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 or 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.

Palatine tonsil cyst in a dog.

A 7-year-old spayed female Doberman Pinscher had a fluctuant red mass that filled the entire crypt of the left palatine tonsil. The mass was surgically excised and was found to be a tonsillar cyst on histologic examination. Because the cyst was lined with pseudostratified epithelium, embryonic origin was the most probable etiopathogenesis.