Objective To investigate the venous drainage in retrograde island flaps by fluorescence tracing technique and to observe the pathway of venous drainage. Methods The 0.1mL venous blood was collected from the marginal ear vein of every rabbit (n=20), respectively, and erythrocytes were separated by centrifugation and then were labeled with FITC. Positive rate and fluorescence intensity of FITC-labeled RBC were detected by flow cytometry. RBC morphous was observed under the inverted fluorescence microscope. Saphenous retrograde island fasciocutaneous flap and antegrade islandfasciocutaneous flap (4.0 cm × 3.0 cm in size with vascular pedicle length of 3.0 cm) were successfully establ ished in hind l imbs of 20 New Zealand white rabbits．One hind l imb of each rabbit was randomly assigned as the experimental group and the contralateral side was assigned as the control. The same flap was establ ished in the control group without any fluorescence tracer. According to retrograde or antegrade flaps, the experimental group was divided into 2 groups with 10 rabbits in each group. And then, according to different pathways of tracer-giving, each group was divided into 2 subgroups of artery and vein, with 5 rabbits in each subgroup. The labeled erythrocytes (5 μL) were injected into artery or vein and then flaps were cut down 5 seconds later. The flaps were immediately frozen and chipped (5-7 μm). Consecutive three frozen sections were made and two of them were stained with HE and GENMED, respectively, but the third one was squashed without staining. All frozen sections were observed under the microscope. Results Positive rate of FITC-labeled RBC was beyond 99% and fluorescence intensity was more than or equal to 103. FITC-labeled RBC showed steady green fluorescence under the inverted fluorescence microscope. Fluorescence appeared in all experimental groups, but none was found in the control groups. In antegrade island flap group, fluorescence appeared mainly in lumen of vein, wall of vein and inner membrane and outer membrane of artery. In retrograde island flap group, fluorescence distributed principally in inner membrane and outer membrane of artery and wall of vein. Conclusion The fluorescence tracing is appl icable to the research of venous drainage. Venous drainage in the antegrade island flaps is mainly through lumen of vein, wall of vein and inner membrane and outer membrane of artery. While, venous drainage in retrograde island flaps is principally through inner membrane and outer membrane of artery and wall of vein.
OBJECTIVE: To investigate the clinical results of the distally based neurocutaneous flap by anastomosis of superficial veins. METHODS: From June 1996, 19 cases with composite skin defects of the distal part of limb were repaired by the transposition of distally based neurocutaneous flaps, including traumatic defect in 10 cases, chronic ulcer in 3 cases, scar contracture in 6 cases. The distally based sural neurocutaneous flaps were used in 9 cases, the reverse-flow saphenous neurocutaneous island flaps were used in 2 cases, and the retrograde neurocutaneous island flaps of the forearm were used in 8 cases. The flap area ranged from 15 x 24 cm to 4 x 6 cm, the pedicle of the flap ranged from 6 cm to 15 cm in length. The superficial vein of the flap were anastomosed with the subcutaneous superficial vein of the recipient site to improve the venous drainage. RESULTS: The composite flap survived completely in 17 cases. One cases with retrograde-flow forearm neurocutaneous flap and another case with reversed sural neurocutaneous flap were partially survived because of thrombosis in anastomosed veins postoperatively. Sixteen cases were followed-up for 6 to 24 months, the color and texture of the flap were excellent, the protective sensation were recovered, the configuration and function were satisfactory. CONCLUSION: Anastomosis of superficial veins of the composite flaps with the subcutaneous superficial veins of the recipient site can significantly improve the venous drainage, enlarge the survival area of the flap and the reparable area.
The skin and soft tissue defects or ulceration of the wight-bearing part of the sole was difficult to repair with medial plantar island flap, but would be treated with retrograde island flap carrying plantar metatarsal arteries as pedicle. Ten flaps were applied in 9 patients. They had either indolent ulcer or skin defect secondary to excision of painful corn or callosities of the front part of the sole. The flaps were 3 cm to 5 cm long and 3 cm to 4 cm wide, and they all survived following retrograde transfer. The patients were followed up for 1 to 10 years. It was found that the patients could bear weight on the operated foot and could walk without pain or lameness. The flaps were resistant to abrasion from long-time walking. It was concluded that this kind of flap was best suitable to repair the ulcers and defects over the front part of the sole despite there were some minor shortcomings such as the size of the flaps available was small and the donor site required split skin graft for coverage.