The role of the venous system in the abdominal flap of the rat.

The abdominal flap of the rat has become a popular model with investigators. Recently, researchers have been reporting survival of skin flaps with varying blood supplies. We studied the viability of skin flaps on a consistent model with varied blood supply. An 8 x 9 cm flap was raised in 40 male Sprague-Dawley rats. The viability of the flaps could be studied in 25 rats. The survival of a pedicled flap based on the left inferior epigastric artery and vein was compared with that of a pedicled flap with enhanced venous drainage. The survival of a venous flap based on the paired inferior epigastric veins and the paired long thoracic veins was compared with that of an arterialized venous flap. A composite graft was used as a control for all groups. A qualitatively improved survival was found in the pedicled venous-enhanced group (66 percent) compared with the pedicled flaps (56 percent) (p > 0.05). An improved survival was found in the arterialized venous flap (57 percent) compared with the venous flap (40 percent) (p < 0.05). All flaps had improved survival compared with the composite graft (0.6 percent) (p < 0.05).

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.

Advanced non-animal microsurgical exercises.

For the novice microsurgeon, suturing simple lines on a static model ill prepares them for the technically difficult live model that is to follow. A practice card was therefore designed to make the transition easier. The basic building block is rubber glove sutured to form a simple tube. From this point, progressive exercises are carried out. These are (1) simple suturing, (2) tube anastomosis, (3) end-to-end anastomosis, (4) end-to-side anastomosis, (5) side-to-side anastomosis, (6) inequality of diameters, and (7) free graft placement. Since the student is faced with problems that are challenging and progressively complex, a noticeable improvement is seen in their skills. These models introduce the student to planning and instrumentation that they would deal with in the clinical situation. Once the student has mastered these exercises, he/she is ready to advance to the rat model.

Frostbite in the prairies: a 12-year review.

A 12-year retrospective review of inpatient frostbite injury was undertaken in three tertiary hospitals serving a northern prairie population of 650,000. In the 125 patients identified, the mean age was 41 years, with a range of 3 to 90 years. Predisposing factors were alcohol consumption (46 percent), psychiatric illness (17 percent), vehicular trauma (19 percent), vehicular failure (15 percent), and drug use (4 percent). Profound hypothermia with a core temperature less than 32 degrees C was present in 12 percent. Anatomic distribution was 19 percent upper extremity, 47 percent lower extremity, 31 percent combined upper and lower extremity, and 3 percent facial or trunk only. Factors correlating with amputation of parts (p < 0.05) were duration of exposure, lack of proper attire, remote site of injury, presence of wound infection, and delay in seeking treatment. Prophylactic systemic antibiotics did not decrease the incidence of wound infection. Comparison with nine other civilian series revealed striking similarities in the patient populations.

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.

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.