Controlled delivery of bFGF remodeled vascular network in muscle flap and increased perfusion capacity via minor pedicle

Background. The vascular pedicles of superficial skeletal muscles are classified as the dominant pedicle and the minor pedicle. The dominant pedicle can reliably provide adequate circulation to the entire muscle, but the minor pedicle cannot. Therefore, it is impossible to elevate an entire muscle flap based solely on the minor pedicle. We evaluated whether the delivery of basic fibroblast growth factor (bFGF) would remodel the vascular network in the muscle flap and increase the perfusion capacity via the minor pedicle. Methods. Using a controlled delivery system with acidic gelatin hydrogel microspheres, bFGF (50 mu g, FGF group) or phosphate-buffered saline (PBS group) was delivered to the rabbit gracilis muscle, which contained a single dominant pedicle and a minor pedicle. Seven days later, the gracilis muscle was elevated as a muscle flap on the minor pedicle, and the flap was wrapped with a silicone sheet to avoid vessel ingrowth from surrounding tissue. At 7 d after operation, flap viability, microangiograms, and regional blood flow were evaluated. Results. Flap viability in the FGF group (73.6 +/- 20.5% was significantly higher than that in the PBS group (19.7 +/- 23.5%). Postmortem angiograms of the flap showed obvious communications between the distal vascular networks of the minor and dominant pedicles. Angiographic score and regional blood flow of the flap were significantly higher in the FGF group than in the PBS group. Conclusions. Controlled delivery of bFGF to rabbit gracilis muscle increased the perfusion capacity via the minor pedicle, and the minor pedicle became able to solely provide sufficient circulation to the entire muscle. (C) 2008 Elsevier Inc. All rights reserved.