Effect of photodynamic therapy on the critical primary ischemic time of fasciocutaneous flaps

Background: Photodynamic therapy (PDT) may be used as an adjuvant intraoper ative therapy to improve locoregional control. PDT has been shown to delay wound healing. This raises concern about PDT's effect on survival of fascio cutaneous flaps. Objective: Evaluate the effect of 1) PDT on the critical i schemic time in a rat fasciocutaneous flap model and 2) photosensitizer act ivation by the surgical light source, Design: A fasciocutaneous flap, based on the left inferior epigastric vessels, was used. Ischemic times of 2, 4, 6, 8, 10, and 12 hours were induced by clamping the vascular pedicle, Anim als were randomly divided into five groups: ischemia only, group I; light t reatment to wound bed, group II; Photofrin before surgery with the flap ele vated without a fiber optic head light, group Iii, or with a headlight, gro up IV; Photofrin prior to surgery with light treatment to the wound bed, gr oup V, Flap survival was assessed on postoperative day 7, Results: The crit ical primary ischemic time of group V (PDT) was significantly less (P < .05 ) than groups I, II, III, and IV, There was no statistical difference in th e critical primary ischemic time when a fiber optic headlight was used (gro up III vs. group IV). Conclusion: Intraoperative PDT significantly reduces the critical primary ischemic time of the rat fasciocutaneous flap. White l ight illumination of the operative field does not result in photosensitizer activation and has no effect on the critical primary ischemic time.