Rectus abdominis free muscle flap for reconstruction in nine dogs

OBJECTIVE: To evaluate the clinical use and outcome of a rectus abdominis microvascular free flap for wound closure in dogs. STUDY DESIGN: Retrospective case series. ANIMALS: Dogs (n=9) with complex extremity or oral wounds. METHODS: Medical records (2002-2006) of dogs that had a rectus abdominis free tissue transfer to close an extremity or oral wound were reviewed. RESULTS: Nine dogs were identified: 5 had distal extremity wounds, 3 had oral palatal defects, and 1 had a large hygroma excised. A rectus abdominis free tissue transfer with a caudal epigastric vascular pedicle was successfully used for management of these wounds. No major complications occurred with the donor site and a good cosmetic and functional outcome occurred in all dogs. CONCLUSION: The rectus abdominis is a versatile muscle that can be used for reconstructing cutaneous and oral defects with repeatable success. CLINICAL RELEVANCE: Free tissue transfer of the rectus abdominis muscle is a clinically useful technique for closure of a variety of difficult soft tissue wounds.     

Achilles Tendon Repair in Dogs Using the Semitendinosus Muscle: Surgical Technique and Short-Term Outcome in Five Dogs

Objective— To describe augmentation of primary Achilles tendon repair using suture with a semitendinosus muscle flap and report outcome in 5 dogs.
Study Design— Prospective clinical study.
Animals— Dogs (n=5) with Achilles tendon rupture (n=6).
Methods— After tendon repair with #2 polypropylene in a 3-loop pulley suture pattern, the lateral one-half of the semitendinosus muscle was transected from the ischium, rotated distally then sutured with #2 polypropylene to the calcaneus in a 3-loop pulley pattern. The epitenon was sutured to the muscle flap fascia with interrupted sutures. All dogs had a bivalved cast for 2 weeks then a cranial splint for 2–6 weeks. Lameness scores (0=stands and walks normally to 4=non-weight-bearing lameness, plantigrade stance on affected pelvic limb) were determined every 2–3 weeks postoperatively for 12 weeks. Outcome was determined from telephone questionnaire of owners.
Results— Four had lameness scores of 0, the 5th had a score of 1 at 12 weeks. Three owners were very satisfied with outcome. Minor complications included cast sores (2 dogs), infection (2), and acute swelling (1); 1 major complication occurred (infection resulting in reoperation).
Conclusions— Semitendinosus flap augmentation resulted in early return to function without prolonged postoperative immobilization. Three dogs returned to full work/activity after repair.
Clinical Relevance— Augmentation of primary Achilles tendon repair with a semitendinosus flap can be considered in dogs with chronic rupture but further investigation of the long-term outcome using this technique is needed.     

Microvascular Free Tissue Transfer of the Rectus Abdominis Muscle in Dogs

OBJECTIVE: To assess donor-site morbidity and survival of the rectus abdominis muscle with an overlying skin graft after free tissue transfer to a medial femorotibial defect in dogs. STUDY DESIGN: Experimental study. SAMPLE POPULATION: Phase 1: 6 canine cadavers; phase 2: 7 adult mixed-breed dogs. METHODS: Phase 1: The rectus abdominis muscle was removed from canine cadavers, muscular and vascular dimensions were recorded, and angiography was performed. Phase 2: Muscular transfer was performed through anastomosis of the caudal epigastric artery and vein to the saphenous artery and medial saphenous vein. Transferred tissues were evaluated on postoperative days 3, 6, 10, and 13. Animals were examined daily until euthanasia between postoperative days 31 and 42. Postmortem angiograms were performed and tissues collected for histopathologic evaluation. RESULTS: Phase 1: Appropriate vascular dimensions for microvascular anastomosis were confirmed and surgical technique perfected. Phase 2: Muscular excision produced minimal donor-site morbidity. All muscles survived after microvascular transfer and angiography confirmed vascular patency. All of the skin grafts survived, with one graft undergoing partial necrosis. CONCLUSIONS: The rectus abdominis muscle can be successfully transferred to a medial femorotibial defect and can serve as a bed for acute skin grafting. No significant donor-site morbidity is associated with its removal. CLINICAL RELEVANCE: Microvascular free tissue transfer of the canine rectus abdominis muscle has not been previously described. This technique provides a new alternative for repair of appropriate wounds. Additional studies are needed to define its utility in clinical patients.     

Transversus abdominis muscle as a gastric or intestinal on-lay flap in two dogs and one cat

Historically, omentalisation and serosal patching have been used to augment gastrointestinal wall defects or incisions where gastrointestinal viability is of concern. This report describes the novel use of a transversus abdominis muscle on-lay flap to augment and provide support to compromised intestine in three cases. The muscle flap was used to support: the ileum following reduction of an intussusception in a dog (case 1), the gastric wall following gastric strangulation, dilation and volvulus in a diaphragmatic rupture in a cat (case 2) and the jejunum following enterotomy and full-thickness ulcer resection with primary repair in a dog (case 3). All animals were discharged within 4 days postoperatively with no short- or long-term complications reported by either the referring veterinary surgeons on routine postoperative examination or on telephone follow-up with the owners (case 1: 10 months, case 2: 30 months, case 3: 6 weeks). The creation of a flap of the transversus abdominis muscle may provide a useful alternative or adjunct to previously described techniques for supporting the gastrointestinal tract when gastrointestinal tissue viability is questionable or resection is not feasible. Further prospective clinical evaluation studies would be indicated to determine whether the muscle flap remains viable or compare whether this technique should be recommended over conventional methods.     

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.     

Use of a pedicled rectus abdominis muscle flap for repair of a failed vesicourethral anastomosis in a dog

A 10-year-old mixed breed dog underwent a prostatectomy for an adenocarcinoma. Within three days the dog had signs of a uroperitoneum. Re-exploration revealed that a portion of the vesicourethral anastomosis had failed. Primary suturing of the tissue along the site of dehiscence following debridement of the devitalised tissue was impossible. A rectus abdominis muscle flap was created and successfully used to repair the site of leakage.     

Free tissue transfer of the rectus abdominis myoperitoneal flap for oral reconstruction in a dog

A five-month-old intact/male Boxer dog was presented 5-days following bite wound trauma to the maxillary region resulting in an oronasal fistula extending from the maxillary canine teeth to the soft palate. Multiple surgical procedures using local, buccal mucosal flaps failed to repair the oronasal fistula. Free tissue transfer of the rectus abdominis myoperitoneal flap using microvascular surgical techniques was successful in providing soft tissue reconstruction of the hard palate area. Complications of these surgical techniques included muscle contraction and subsequent muzzle distortion. Small, refractory oronasal fistulae at the perimeter of the myoperitoneal flap were repaired by primary wound closure.     

Herniation of the abdominal wall in pregnant mares

Abdominal wall hernia was detected in 4 pregnant mares. Antemortem diagnosis of the specific abdominal wall lesion was difficult. Ventral deviation of the abdomen, associated abdominal wall edema, and pain indicated rupture of the prepubic tendon. Three mares examined at necropsy did not have a rupture of the prepubic tendon but did have herniation of the abdominal wall. Abdominal pain was severe and was compounded by incarceration or entrapment of viscus.     

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.     

Surgical treatment of an elbow hygroma utilizing microvascular free muscle transfer in a newfoundland

Microvascular free muscle transfer utilizing the rectus abdominis muscle, in combination with a mesh skin graft and transarticular external fixator, were used following the surgical excision of an elbow hygroma in a Newfoundland dog. Postoperatively, the dog did well with minimal complications and has yet to have a recurrence 10 months following surgery. This report describes the utility and successful use of the rectus abdominis free tissue transfer in the surgical correction of a difficult elbow hygroma in the dog.     

The management of tendon injuries in dogs

An account is provided of the management of 68 dogs with tendon injury. Of the 33 with Achilles rupture, 23 sustained tendon severance, seven had disrupted the gastrocnemius muscle/tendon junction, and in three an attachment of the gastrocnemius was avulsed. The standard operative procedure comprised fixing the hock in extension with a screw, and exploring the damaged structures with a view to repair and the introduction of carbon fibre implants. The majority regained normal limb use and the main complications concerned loosening or fracture of the screw. The 32 with digital flexor tendon severance had cuts, on a fore foot in nine and a hind foot in 23. Exploration and reconstruction were routinely practised and carbon fibre implants were frequently used. The standard of recovery was good in those dealt with fresh but was less satisfactory in chronic cases. The two dogs with digital extensor tendon and the one with flexor carpi ulnaris tendon severance responded well to repair.     

Cranial Sartorius Muscle Flap in the Dog

An anatomic study was performed on canine cadavers to define the blood supply to the cranial sartorius muscle. The vascular supply to this muscle was found to be a single dominant pedicle branching from the femoral artery at the proximal portion of the muscle. This anatomic information was applied in designing a study to determine the feasibility of performing a cranial sartorius muscle flap in the dog. The cranial sartorius muscle was transposed to the caudal abdominal region in four dogs. The muscle flap was based on the singular vascular pedicle defined in the anatomic study. All muscle transpositions were successful on day 19 as evidenced by gross appearance and 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, proliferative and maturing granulation and fibrous connective tissue, and mild to moderate mononuclear inflammation. Seroma formation and infection were the two postoperative complications noted. The cranial sartorius muscle flap has potential clinical application for repair of traumatic caudal abdominal hernias and large inguinal hernias in the dog.     

Effect of Fascial Closure Technique on Strength of Healing Abdominal Incisions in the Dog A Biomechanical Study

Load-deformation data were used to determine the strength of healing abdominal incisions in dogs at 7, 14, and 21 days after wounding. The breaking energy of paramedian incisions closed by suturing the internal and external leaves of the sheath of the rectus abdominis muscle vs. incisions closed by suturing the external leaf only was similar in the 12 dogs studied. Closure of abdominal incisions by suturing only the external leaf of the rectus sheath provided wound strength comparable to the traditional method.     

Unusual muscle and tendon disorders of the forelimb in the dog

Five dogs with unusual muscle and tendon disorders of the forelimb are described. In one dog, mineralisation of the tendon of insertion of the supraspinatus muscle was treated surgically but lameness returned following the resumption of exercise. Of two cases of avulsion of the origin of the extensor carpi radialis muscle, one was successfully managed conservatively while the other needed surgical intervention to resolve the lameness. A single case of chronic avulsion/rupture of the tendon of insertion of the extensor carpi radialis muscle was successfully managed conservatively while a case of medial displacement of the biceps brachii tendon was surgically corrected by repair of the transverse humeral ligament. The aetiology, diagnosis and management of the above conditions is discussed.     

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.     

Laparoscopic-assisted enterostomy tube placement and full-thickness biopsy of the jejunum with serosal patching in dogs

OBJECTIVE: To develop laparoscopic-assisted techniques for enterostomy feeding tube placement and full-thickness biopsy of the jejunum in dogs. ANIMALS: 15 healthy dogs. PROCEDURE Dogs were anesthetized, and positive pressure ventilation was provided. A trocar cannula for the laparoscope was inserted on the ventral midline caudal to the umbilicus. For enterostomy tube placement, a second trocar cannula was placed lateral to the right rectus abdominis muscle, and a Babcock forceps was used to grasp the duodenum and elevate it to the incision made for the cannula. The duodenum was sutured to the abdominal wall, and a feeding tube was inserted. For jejunal biopsy, a third trocar cannula was placed lateral to the left rectus abdominis muscle. A portion of jejunum was elevated to the incision for the second or third cannula, and a full-thickness biopsy specimen was obtained. A second specimen was obtained from another portion of jejunum, and retention sutures for the 2 biopsy sites were tied so that serosal surfaces of the biopsy sites were apposed to each other. Dogs were euthanatized 30 days after surgery. RESULTS: The enterostomy tube was properly positioned and functional in all 8 dogs that underwent laparoscopic-assisted enterostomy tube placement, and sufficient samples for histologic examination were obtained from all 7 dogs that underwent laparoscopic-assisted jejunal biopsy. None of the dogs had any identifiable problems after surgery. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that in dogs, laparoscopic-assisted procedures for enterostomy tube placement and jejunal biopsy are an acceptable alternative to procedures performed during a laparotomy.     

Vesicocutaneous fistulation following prepubic tendon rupture in a bitch

A case of vesicocutaneous fistula formation following traumatic rupture of the prepubic tendon is described. The radiographic diagnosis and treatment are presented.     

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.     

Effect of Two Muscle Sling Techniques on Early Morbidity after Femoral Head and Neck Excision in Dogs

Femoral head and neck excision was performed on the left coxofemoral joint of 18 dogs. The osteotomy site was padded with a partial-thickness biceps femoris muscle sling in one group of six dogs, and with a deep gluteal muscle flap in another group of six dogs. In a third group of six dogs, a partial-thickness biceps flap was created and sutured back in its original location. The dogs were monitored daily for 3 weeks for degree of lameness, range of motion, fever, and postoperative complications. Dogs with intra-articular muscle pads were less lame and had a greater range of motion in the treated hip than dogs without intra-articular muscle pads. Dogs with biceps slings showed more improvement in limb function and range of motion than did dogs with deep gluteal flaps. There were no significant differences in mean temperature elevations and no clinically significant postoperative complications. Use of a partial-thickness biceps muscle sling or a deep gluteal muscle flap decreased the chances of early postoperative morbidity and provided an earlier return to function. The partial-thickness biceps sling appeared to be more beneficial than the deep gluteal flap.