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.     

Rectus abdominis muscle flap for repair of prepubic tendon rupture in 8 dogs

The clinical use and outcome of the rectus abdominis muscle flap to repair prepubic hernias were evaluated retrospectively. Medical records (2002-2007) of 8 dogs that had a rectus abdominis muscle flap to repair traumatic prepubic tendon rupture were reviewed. Only minor donor site complications were noted, including self-limiting ventral and hind-limb swelling. No long-term complications including recurrence of hernia were noted. The results of this study indicate that the rectus abdominis muscle flap is a clinically useful option for repairing prepubic tendon rupture in 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 use of vacuum-assisted closure therapy for the treatment of distal extremity wounds in 15 dogs

Objective— To evaluate clinical outcome after vacuum-assisted closure (VAC) therapy in dogs with traumatic wounds located in the distal extremities and report our early experience with VAC.
Study Design— Retrospective study.
Animals— Dogs (n=15) with traumatic distal extremity wounds.
Methods— Medical records (1999–2003) of dogs with traumatic injuries to the distal extremities managed by VAC were evaluated. Data included signalment, location of wound, time until surgical intervention, wound reconstruction methods, orthopedic procedures, outcome, complications associated with VAC, and length of hospitalization.
Results— The mean number of days until reconstruction was 4.6 days (range, 2–7 days). Reconstructive surgery was successful in all cases. Mean hospitalization was 9.7 days (range, 6–16 days). Complications included dermatitis at the wound margin and loss of vacuum causing wound desiccation.
Conclusion— VAC therapy can be used to achieve adequate management of traumatic distal extremity wounds. VAC provides an effective method of securing skin grafts over the wound bed.
Clinical Relevance— VAC therapy can be used as an ancillary treatment for distal extremity wounds in dogs before surgical repair as well as a method for securing skin grafts to the wound bed.     

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.     

Treatment of degloving injuries with autogenous full thickness mesh scrotal free grafts

In this report, we evaluated the effectiveness of scrotal tissue as an autogenous free skin graft to treat cutaneous degloving injuries of the distal limb in dogs. Surgery was performed on two male intact dogs with distal extremity degloving wounds. Dog #1 had a tarsal degloving wound with exposure of the distal tibial and tarsal bones. Dog #2 had a degloving injury over the metacarpals. Wounds were treated with daily wet-to-dry bandages in order to develop a healthy bed of granulation tissue at the graft recipient site. Scrotal ablation castration was performed once the recipient site had been prepared. Subcutaneous and adipose tissue were excised from the scrotal graft and mesh slits were created. The graft was applied to the recipient site with monofilament absorbable simple interrupted sutures. Bandaging was performed postoperatively, and bandage changes occurred four, seven, nine and 11 days postoperatively. Follow-up was performed at 30 days. In dog #1, the tarsal degloving injury graft had first intention healing with 100% graft take on day 11. In dog #2, the metacarpal degloving injury graft had 90% graft take on day nine, with second intention healing adjacent to the fifth digit pad. The scrotum is often discarded at the time of scrotal ablation castration. Distal extremity wounds can be successfully treated with free skin grafts. In male dogs, the scrotum is a viable option as a full thickness mesh free graft for distal extremity reconstructive surgery.     

Bilateral skin fold rotation-advancement flaps for the closure of large lumbosacral wounds in three dogs

Three dogs were presented for the management of disease processes resulting in large skin defects over the dorsal lumbosacral region. One had severe dog bite wounds, one had a large burn sustained from a heating pad and one had a large myxosarcoma in the region. In each case, the extent and location of the resulting skin defect were assessed as factors likely to prevent reconstruction using simple tension-relieving techniques alone or in combination with established reconstructive techniques, such as axial pattern flaps or skin stretching devices. Bilateral skin fold rotation-advancement flaps (SFRAFs) based on the flank folds were mobilised dorsally and allowed complete wound closure in two dogs and subtotal closure in the other dog. All wounds healed without major complications and an acceptable cosmetic outcome was achieved in each case. Minor flap debridement was required in two dogs. The use of bilateral SFRAFs is a useful technique alone or in combination with other reconstructive techniques for the closure of large dorsal lumbosacral skin defects when existing techniques are not sufficient. Small flank folds, such as those of obese dogs, may yield unexpectedly large SFRAFs.     

Clinical evaluation of random skin flaps based on the subdermal plexus secured with sutures or sutures and cyanoacrylate adhesive for reconstructive surgery in dogs

OBJECTIVE: To evaluate the use of subdermal plexus skin flaps for closing defects after excision of cutaneous and subcutaneous tumors in dogs and to compare outcome of flaps secured with sutures and those secured with butyl-cyanoacrylate and intermittent sutures. STUDY DESIGN: Clinical study. ANIMALS: Fifteen dogs. METHODS: After excision of cutaneous or subcutaneous tumors the skin defect was reconstructed by random flaps based on the subdermal plexus. Flap skin edges were apposed with simple interrupted 4-0 monofilament nylon sutures (group 1; 5 dogs) or nylon sutures alternated with butyl-cyanoacrylate adhesive (group 2; 10 dogs). Flaps were evaluated every 48 hours when bandages were changed, until complete healing. RESULTS: Random flaps based on the subdermal plexus were effectively used to close wound defects; mean flap survival was 89%. Partial flap necrosis occurred in 4 dogs. Wound margins apposed with butyl-cyanoacrylate had thinner and more esthetic scars than sutured margins. CONCLUSION: Random flaps based on the subdermal plexus proved to be versatile for covering limb wounds after excision of cutaneous or subcutaneous tumors. Mean survival rate was comparable to that reported for axial pattern flaps. Butyl-cyanoacrylate adhesive was easy to apply, allowed accurate margin apposition with good cosmetic outcome and reduced sutures needed. CLINICAL RELEVANCE: Cyanoacrylate adhesive should be considered in lieu of suture closure to secure random skin flaps based on the subdermal plexus 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.     

Correlation Between Peritonitis and Incisional Infections in Horses

Surgical site infection of abdominal incisions is an important complication after laparotomy with increased risk of incisional hernia formation in horses. This study aims to evaluate the healing process of abdominal incisions and correlate peritonitis with the occurrence of surgical site infection and incisional hernias. Nine horses underwent standardized laparotomy, intestinal exploration, and induced septic peritonitis. Standardized relaparotomy was performed two (n = 3), four (n = 3), and six (n = 3) months later to evaluate the abdominal cavity for adhesions and to collect the sutured ventral abdominal wall to evaluate and prepare it for histopathological and tensile strength study. All horses presented with endotoxemia, controllable peritonitis, heat and touch-sensitive ventral abdominal edema and surgical wound infection with presence of purulent discharge. Adhesion of the cecum or colon to the internal portion of the surgical wound was observed. Healing of the infected surgical wounds occurred by second intention and a space between the rectus abdominis muscles developed because of the presence of a scar, which was related to incisional hernia. In the histopathological evaluation, the collagen content increased, and the inflammation decreased over time. The tensile strength increased over time and was highest after 6 months. After the second surgical intervention, there was no infection of the surgical wound in any of the animals and healing by first intention occurred. Surgical site infection may be a symptom of peritonitis in horses recovering from abdominal surgery. Infected surgical wounds heal by second intention, which favors the spacing of rectus abdominis muscle and the formation of incisional hernia.     

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.     

Cutaneous wound healing in the cat: a macroscopic description and comparison with cutaneous wound healing in the dog

OBJECTIVE: To describe the macroscopic features of first and second intention cutaneous wound healing in the cat and compare with the dog. STUDY DESIGN: Experimental study. ANIMALS: Domestic shorthaired cats (6) and beagle dogs (6). METHODS: Square, open cutaneous wounds created on the dorsal aspect of the thorax were evaluated for 21 days for temporal and spatial development of granulation tissue, wound contraction, epithelialization, and total healing. To evaluate first intention healing, breaking strength of sutured linear cutaneous wounds was measured at 7 days post-wounding. Laser-Doppler perfusion imaging was used to measure cutaneous perfusion. RESULTS: First intention healing: sutured wounds in cats were only half as strong as those in dogs at day 7 (0.406 versus 0.818 kg breaking strength). Second intention healing: cats produced significantly less granulation tissue than dogs, with a peripheral, rather than central distribution. Wound epithelialization and total wound healing (total reduction in open wound area from contraction and epithelialization) were greater for dogs than for cats over 21 days. Wound contraction on day 7 was greater for dogs, but not on day 14 or 21. Cutaneous perfusion was initially greater for dogs than for cats, but no differences were detected after day 7. CONCLUSIONS: Significant, previously unreported differences in cutaneous wound healing exist between cats and dogs. In general, cutaneous wounds in cats are slower to heal. Cats and dogs also appear to use different mechanisms of second intention healing. In cats wounds close mainly by contraction of the wound edges, whereas in dogs wounds close more from central pull, and epithelialization. CLINICAL RELEVANCE: Surgeons should view the cat as a unique species, which presents its own special challenges in wound healing, and should take this into account when planning treatment of feline wounds, either by primary closure, or by second intention healing.     

Distant abdominal and thoracic pedicle skin flaps for treatment of distal limb skin defects

The treatment of large skin defects of the distal limbs of dogs and cats can be difficult due to the lack of skin available for primary wound closure or the creation of local skin flaps. Distant pedicle skin flaps provide an acceptable alternative for wound closure with full thickness skin and provide a cosmetic result. Fourteen animals (10 dogs and four cats) that had distant pedicle skin flaps are reviewed. The technique allowed 100 per cent wound coverage in 10 of 14 animals and greater than 95 per cent skin flap survival occurred in 12 of 14 animals. Complications associated with the procedure were most commonly wound infection and partial suture line dehiscence, however these did not detract from the final outcome. Flap release was in one or two stages, however the outcomes did not appear to be affected by the release protocol.     

Microvascular transplantation of a free omental graft to the distal extremity in dogs

OBJECTIVE: To assess the survival of a free omental graft applied to an experimentally created wound on the distal extremity in dogs. STUDY DESIGN: A free omental graft was evaluated as a primary method of treatment for dogs with distal extremity wounds in an experimental model. ANIMALS OR SAMPLE POPULATION: Five adult intact female mixed breed dogs weighing 21.8 kg to 25.0 kg. METHODS: A free omental graft was harvested from the abdomen and transferred to a wound bed overlying the medial aspect of the tibia. A microvascular anastomosis was performed between the graft vessels and vessels at the recipient site. Daily clinical assessment of graft viability was performed. Angiography and 99mTechnetium labeled macroaggregated albumin (99mTc MAA) scintigraphic perfusion scans were performed on either day 4, 5, or 7. Postmortem collection of tissues for histopathologic analysis was performed immediately after imaging. Total operative time and graft ischemia time were evaluated for effects on graft survival. RESULTS: Two of seven grafts survived to the end of the study, three of seven grafts failed because of ischemia, and two of seven grafts failed because of self-trauma. There was no clinically significant morbidity associated with the abdominal portion of the procedure. Because of the small number of surviving grafts, the effects of operative time and graft ischemia time could not be statistically evaluated. CONCLUSIONS: Microvascular transplantation of a free omental graft can result in a viable tissue covering of a distal extremity wound, however, the failure rate is unacceptably high. CLINICAL RELEVANCE: A free omental graft may not have sufficient durability to be an acceptable wound covering by itself. Further studies combining omentum with a skin graft or other tissues may result in a clinically useful technique.     

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.     

Comparison of the role of the subcutaneous tissues in cutaneous wound healing in the dog and cat

Objective— To describe and compare the contribution of the subcutaneous tissues to 1st and 2nd intention cutaneous wound healing in the dog and cat.
Study Design— Experimental study.
Animals— Domestic shorthaired cats (n=6) and 6 beagle dogs.
Methods— Paired wounds were created on either side of the dorsal midline; the subcutaneous tissue was removed on 1 side and left intact on the other. Square, open wounds of the dorsal aspect of the thorax were observed for 21 days to monitor granulation tissue formation, wound contraction, epithelialization, and total healing (contraction+epithelialization). Breaking strength of sutured linear wounds was measured 7 days after wounding. Laser-Doppler perfusion imaging (LDPI) was used to measure cutaneous perfusion.
Results— First intention healing: subcutaneous tissue removal had no consistent effect on sutured wound strength at 7 days in dogs or cats. Second intention healing: removal of subcutaneous tissue reduced wound perfusion, granulation, contraction, epithelialization, and total healing. Granulation tissue formation and wound contraction were delayed to a significantly greater degree in cats than in dogs ( P <.05). Two dogs (33%) had minor wound infections.
Conclusions— The subcutaneous tissues make an important contribution to 2nd intention cutaneous healing. Dog and cat wounds had delayed 2nd intention healing when subcutaneous tissues were removed; wounds in dogs, but not cats, had largely recovered from this delay by 21 days.
Clinical Relevance— Extensive debridement of subcutaneous tissue may delay wound healing particularly in feline patients. A higher risk for wound infections may accompany extensive removal of subcutaneous tissues in dogs.     

Partial Maxillectomy in the Dog Comparison of Suture Materials and Closure Techniques

This study compares the healing of oronasal defects created by partial maxillectomy when closed using two different suture materials and two different suture patterns. In experiment 1, 24 dogs were divided into four equal groups. Partial maxillectomy was performed on each dog and was closed using either a two-layer simple interrupted suture pattern (12 dogs) or a modified Mayo mattress pattern (12 dogs) with either polyglactin 910 (12 dogs) or polypropylene (12 dogs) sutures. On the seventh postoperative day, the dogs were euthanized, suture line bursting pressures were measured, and wound healing was evaluated grossly and histopathologically. Suture line dehiscence occurred in one dog from each of the four groups. These were the only dogs in which electrocoagulation had been used. The healing of suture lines closed with the two-layer simple interrupted pattern was superior to that of those closed with the modified Mayo mattress pattern based on the degree of gross oral ulceration, suppurative inflammation, fibrosis and oral epithelial covering at the suture line, and the number of necrotic sites in the adjacent tissue. The healing of suture lines closed with polypropylene was superior to that of those closed with polyglactin 910 based on suture line bursting pressures and the degree of suppurative inflammation and tissue necrosis at the suture sites. In Experiment 2, partial maxillectomies were performed on four dogs, and closure was achieved using a two-layer simple interrupted suture pattern with either polyglactin 910 (two dogs) or polypropylene (two dogs). On the 30th postoperative day, the dogs were euthanized, and wound healing was evaluated grossly and histopathologically. All suture lines were well healed. All polyglactin 910 oral sutures were absent, while all polypropylene oral sutures were still present.     

Severe carpal and tarsal shearing injuries treated with an immediate arthrodesis in seven dogs

The medical records of seven dogs with severe, grade 3, open shearing wounds of the carpus or tarsus that were treated with an immediate arthrodesis were reviewed. Six dogs were managed with a transarticular external skeletal fixator (ESF), and one dog was treated with plate fixation. The soft tissues were managed simultaneously along with the definitive joint stabilization in all cases. Minor complications occurred in four dogs: one dog that required a skin graft, one dog in which a skin graft was recommended but not performed, one dog in which a secondary skin closure was performed, and one dog in which a delayed cancellous bone graft was placed. Major complications occurred in three dogs: two dogs that required restabilization of the arthrodesis and one dog that required implant (i.e., plate) removal due to infection. All dogs healed with acceptable functional and cosmetic results. Further long-term evaluation of five dogs revealed that all but one dog had either excellent or good functional outcomes, and the remaining dog had a fair outcome. Similarly, five dogs had either excellent or good cosmetic outcomes, with the remaining dog having a fair outcome. All owners were very satisfied with the overall results. This clinical study demonstrated that an immediate, definitive management technique, in which bone fusion and wound management are undertaken as simultaneous objectives, is a viable technique of managing severe periarticular shearing injuries. Transarticular stabilization with an ESF is the technique 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.     

Open Nasal Cavity and Frontal Sinus Treatment of Chronic Canine Aspergillosis

Five dogs with nasal aspergillosis were treated by surgical exposure and delayed closure of the nasal cavity and involved frontal sinus. Diseased tissue was excised, and 10% povidone-iodine solution was applied three times daily with cotton-tipped applicators. Skin wounds were closed at weeks 6 through 8. In one dog, the frontal sinus was partially obliterated with a temporalis muscle flap before skin closure. At months 6 through 34, all dogs were clinically free of aspergillosis. Open treatment has potential clinical application as a primary approach to nasal aspergillosis or for cases that are unresponsive to previous medical management.