Caudal Sartorius Muscle Flap in the Dog

An anatomic study was performed on canine cadavers to define the blood supply to the caudal sartorius muscle. The vascular supply to this muscle was segmental with the saphenous artery and vein providing a distal vascular pedicle. Anastomotic channels existed between distal and proximal capillary beds within the muscle belly. This anatomic information was used to determine the feasibility of performing caudal sartorius muscle flaps in dogs. The caudal sartorius muscle was transposed to the medial tibial region in four dogs. The muscle flap was based on a singular vascular pedicle of the saphenous artery and vein. The muscle transpositions were all successful on day 14 as evidenced by gross appearance and results of histologic examination. Grossly, the muscles were well adhered to the recipient sites and were covered by connective tissue. Histologically, the specimens were characterized by viable skeletal muscle fibers, large amounts of granulation tissue, varying degrees of inflammatory response, and small foci of myocyte necrosis (2 cases). Seroma formation was a consistent postoperative complication.     

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.     

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.     

Treatment of Trochanteric Ulcers with Cranial Sartorius and Rectus Femoris Muscle Flaps

Five dogs with pressure ulcers over the greater trochanter were treated by debridement and transposition of the cranial part of the sartorius or the rectus femoris muscle. Both muscles had vascular anatomy that allowed transposition based on a major vascular pedicle. All wounds healed promptly by primary intention and no ulcer recurred. The cranial sartorius flap technique was easier to perform than the rectus femoris technique.     

A novel internal abdominal oblique muscle flap to close a major abdominal wall defect

This report describes a novel technique for abdominal wall reconstruction using an internal abdominal oblique muscle flap in an Australian kelpie. En bloc resection of a chondrosarcoma and biopsy scar centred on the 13th rib was performed to include full thickness thoracic wall (12th rib, extending caudally) and lateral abdominal wall (including the vascular pedicle of the external abdominal oblique muscle). The diaphragm was advanced to close the thorax. A flap using the caudal internal abdominal oblique muscle with the base dorsally was elevated and rotated 90° to fill the dorsal defect. The ventral defect was closed using the composite ventral abdominal muscles. The skin was closed primarily. The dog developed a self-resolving seroma. Twelve months postoperatively, the dog was able to engage in agility competitions. A viable muscle flap using the internal abdominal oblique muscle provides a useful alternative to previously described techniques for autogenous closure of a large abdominal wall wound.     

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.     

Autologous tunica vaginalis communis flap for repairing an abdominal wall hernia in a dog

An 8-year-old, intact male miniature dachshund dog, weighing 8.6 kg, was presented with a soft swelling in the caudal abdominal region, including both sides of the groin area. Laparotomy revealed a severe caudal abdominal wall hernia with atrophy of the rectus abdominal muscle. The defect was repaired using a tunica vaginalis communis flap following a standard open prescrotal castration. There were no complications or recurrence of the hernia at 11 months after surgery. This surgical technique involves autogenous reconstruction, is easy to perform, and requires minimal dissection. The tunica vaginalis communis flap has potential clinical applications for repairing caudal abdominal wall hernias in male dogs.     

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.     

Applications of a semitendinosus muscle flap in two dogs

The proximal half of the semitendinosus muscle can be used as a versatile vascularized local transposition flap to reconstruct anatomic faults in the adjacent perineum in dogs. The flap is easy to dissect, and the arc of rotation is considerably beyond the midline. The location, size, and direction of the major vascular pedicle from the caudal gluteal artery is conducive to dependable flap perfusion.     

A comparative histochemical and morphometric study of canine skeletal muscle.

The purpose of this study was to determine whether there were differences in skeletal muscle properties in the hindlimb muscles of different types of dogs. Muscle samples were obtained from the gracilis, sartorius cranial head, sartorius caudal head and tibialis anterior muscles of mixed-breed and hound-type dogs and Beagles. Fiber type, fiber size and capillary morphometry determinations of each muscle from each dog were made from sections stained for myofibrillar ATPase activity. Individual animals were bilaterally symmetric for all measured variables. Fiber type, fiber size and capillary geometry varied between dogs of a given type and muscles within a given dog. There were no differences between dog types for fiber type or fiber size; significant variation in log(muscle)/log(body) mass ratios between dog types was observed for all muscles. The results indicate that for a given muscle, significant variation can occur in skeletal muscle characteristics between different types of dogs and that these differences can be independent of differences in exercise history.     

Sartorius muscle contracture in a German shepherd dog

Objective— To report sartorius muscle contracture in a dog.
Study Design— Case report.
Animals— A 5-year-old, male, German Shepherd dog.
Methods— After a 2-month history of right hindlimb lameness was treated by tenectomy of the caudal sartorius muscle for sartorius muscle contracture.
Results— One month after surgery there was complete remission of clinical signs; however, after 12 months, there was partial reunion of sartorius caudal belly and onset of gracilis muscle contracture.
Conclusions— Contracture of the sartorius muscle in dogs is seemingly rare and similar to gracilis muscle contracture with which it may be confused. Differentiation requires knowledge of muscular anatomy, careful palpation, and surgical inspection.
Clinical Relevance— Sartorius muscle contracture can be treated by tenectomy or removal of contracted muscle tissue, however, long-term outcome suggests the need to develop approaches that prevent recurrence caused by scarring of transected tissues.     

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 1 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.     

Identification and anatomic categorization of the vascular patterns to the pelvic limb muscles of dogs

The vascular patterns to pelvic limb muscles were studied in 6 dogs (12 limbs) to identify muscles most suitable for transposition in the treatment of large wounds. Gross dissection of injected specimens and angiography were used to identify the vascular pedicles. The vascular pedicles to several muscles were generally consistent, and any variations would not interfere with most muscle transfers. The cranial part of the sartorius, gracillis, semitendinosus, and rectus femoris muscles were identified as suitable candidates for transfer. The caudal part of the sartorius, cranial tibial, and long digital extensor muscles have segmentalized vascular patterns that would limit its arc of rotation.     

Development of a Free Latissimus Dorsi Muscle Flap in Cats

Anatomic and experimental evaluation of the feline latissimus dorsi muscle was performed to assess its potential use as a free muscle flap. In the anatomic study, nonselective angiography of the subscapular artery was performed in nine heparinized feline cadavers. The muscle dimensions and vascular anatomy of the dissected latissimus dorsi muscle were recorded. In the experimental study four cats underwent heterotopic transplantation of a partial latissimus dorsi flap, and three cats underwent orthotopic transplantation of a complete latissimus dorsi flap. The mean length and width of the latissimus dorsi muscle was 19.0 and 5.4 cm, respectively. The dominant vascular pedicle was the thoracodorsal artery and vein. The average length and diameter of the thoracodorsal artery was 2.7 cm and 0.6 mm, respectively. Minor vascular pedicles were provided by branches of the intercostal arteries. Numerous choke anastomoses existed between the two pedicle systems. Viability of muscle flaps based on subjective evaluation, angiography, and histopathology, was 66% and 100% in the heterotopic and orthotopic studies, respectively. Flap failure seemed to be caused by both arterial and venous thrombosis. The latissimus dorsi muscle flap met criteria required for application in microvascular reconstruction. The vascular pattern was appropriate and consistent. Donor site morbidity was low, whereas surgical accessibility was high. The muscle satisfied the physical criteria of a free flap. Long-term anastomotic patency and flap viability was shown.     

Sciatic perineal hernia in two dogs

A sexually intact, male Chihuahua and a spayed female poodle were presented with left perineal masses. The masses were identified as perineal hernias by rectal palpation. Surgical exploration of the perineal region in each dog revealed retroperitoneal fat protruding between the sacrotuberous ligament and the coccygeus muscle (sciatic perineal hernia). The hernias were repaired using modifications of the standard or internal obturator flap herniorrhaphies. The levator ani muscle was grossly and histologically normal in the Chihuahua and grossly normal in the poodle. No short- or long-term complications were reported in either case. The management of sciatic perineal hernia is similar to the more common caudal perineal hernia.     

Use of the scrotum as a transposition flap for closure of surgical wounds in three dogs

OBJECTIVE: To describe use of the scrotum as a pedicle flap to cover defects created by tumor excision in the perineum or caudal and medial aspect of the thigh. STUDY DESIGN: Clinical study. ANIMALS: Three dogs. METHODS: After tumor excision and prescrotal castration, an incision was made around the base of the scrotum, leaving a pedicle on the side opposite the skin defect. After removal of the tunica dartos and abdominal fascia, the scrotal skin was stretched and shaped to the defect, then sutured in position with a simple interrupted pattern. Bandages that were changed every 48 hours compressed the flaps, and healing was observed until sutures were removed. RESULTS: Two dogs had first intention healing in 15 days, whereas 1 dog developed necrosis of 10% of the flap, and this area healed by second intention. CONCLUSION: In male dogs, the scrotal skin can be used as a pedicle flap for reconstructive surgery of wounds in the perineum and the proximomedial and caudal aspect of the thigh. CLINICAL RELEVANCE: The perineal region remains a surgical challenge because of the lack of the available skin for reconstruction of surgical wounds. The scrotal skin should be considered for use as a transposition flap to cover skin defects in this region.     

Anatomic and radiologic observations of the clavicle of adult dogs

In an anatomic and radiologic study of the clavicle of 50 adult dogs of 10 breeds, the clavicle had ossified in 96% of the dogs. The clavicles studied had various shapes, and each clavicle was attached to the caudomedial part of the clavicular intersection of the brachiocephalic muscle, to the mastoid part of the cleidocephalic muscle, and to 4 radiating bands of connective tissue fasciculi. One band was attached to the caudal border of the scapula and fascia deep to the latissimus dorsi muscle, 1 was attached to the manubrium of the sternum, and 1 each was attached to the epimysia of the superficial pectoral and sternocephalic muscles. We concluded that, during movements of the thoracic limb, the clavicle and the 4 fasciculated connective tissue bands associated with it stabilize the position of the brachiocephalic muscle with relation to the crest of the greater tubercle of the humerus. Also, the fasciculated band attached to the caudal border of the scapula provides protection for nerves from the brachial plexus and axillary blood vessels that supply the thoracic limb.     

Surgical Anatomy for Desmotomy of the Accessory Ligament of the Superficial Digital Flexor Tendon (Proximal Check Ligament) in Horses

Dissections were performed to study the surgical anatomy for desmotomy of the accessory ligament of the superficial digital flexor tendon (proximal check ligament [PCL]). The surgical approach was initiated by incising the skin cranial to the cephalic vein and caudal to the distal radius. A palpable foramen in the antebrachial fascia that transmits a branch of the cephalic vein was used to advance deeper dissection. After the antebrachial fascia was incised, the fan-shaped PCL was exposed by retracting the en-sheathed tendon of the flexor carpi radialis muscle caudally. Desmotomy was performed gradually to avoid severing branches of the palmar carpal rete that pervade the ligament. Complete transection was evidenced by visualization of the membranous roof of the carpal canal distally, the muscle belly of the radial head of the deep digital flexor centrally, and loose areolar connective tissue along the caudal radius proximally. The vessels of the palmar carpal rete were visible coursing between the severed edges of the PCL. This report highlights relevant anatomic landmarks to facilitate an accurate desmotomy.     

Internal thoracic artery-caudal epigastric artery as a collateral pathway in a dog with aortic occlusion: a case report

Aortic occlusion is a rare vascular disorder in the dog. This report describes the clinical feature of an aged Boxer with complete occlusion of the abdominal aorta caused by an intraluminal thrombus. Angiography evidenced a collateral circulation, represented by the internal thoracic artery, the cranial epigastric artery and the caudal epigastric artery, providing adequate blood flow to the pelvis and pelvic limbs. This vascular network has only recently been recognised as one of the major collateral pathways for arterial blood supply to the pelvis and lower extremities in humans with chronic aorto-iliac occlusive disease (CAOD). Furthermore, a femoral artery Doppler waveform, characterised by low amplitude, a monophasic systolic wave with blunted parabolic flow profile and a small spectral window, peculiar to humans with CAOD, is documented for the first time in a dog with aortic occlusion.     

Misapplication of Subcutaneous Pedicle Flaps in the Dog

Subcutaneous pedicle flaps were created in 21 dogs, 1) with an intact underlying panniculus muscle, 2) with a severed panniculus muscle, and 3) devoid of an underlying panniculus muscle. The survival rates of the resultant grafts were evaluated over a minimum of ten days. All 19 subcutaneous pedicle flaps survived when the underlying panniculus muscle was intact. Nineteen of 23 flaps with a severed panniculus muscle, however, developed necrosis. The survival rates between these two groups were significantly different (p < 0.01). Eight of 14 flaps developed without an underlying panniculus muscle underwent necrosis. Their survival rate was significantly different from flaps with an intact panniculus muscle (p < 0.01) but not significantly different from flaps without an intact panniculus muscle (p < 0.1). Four of 23 subcutaneous pedicle flaps with severed panniculus muscles and six of 14 flaps without an underlying panniculus muscle survived, despite apparent vascular compromise. Six of these grafts survived by accidental incorporation of a direct cutaneous artery and vein beneath the graft. Results from this experiment indicate that subcutaneous pedicle flap development in the dog has a high incidence of necrosis unless a panniculus pedicle to the overlying skin is preserved. As such, they have no advantage in the dog over safer and simpler closure techniques, which preserve the cutaneous circulation.