Radiotherapy as a risk factor for free flap failure has been widely debated. The purpose of this study was to investigate vascular complications in free flap surgery at a center advocating preoperative radiotherapy. On the basis of previous experimental studies, we also aimed to investigate temporal aspects of vascular complications in both arteries and veins. Furthermore, we aimed to study the effect of tissue plasminogen activator (tPA), because irradiated microvascular recipient vessels are associated with impaired fibrinolysis.A retrospective review was conducted for 344 consecutive head and neck microvascular reconstructions. Radiotherapy was administered previously in 283 (82%) of the cases, median dose 64 Gy. Flap outcome, vascular complications, and salvage attempts were identified, along with time elapsed from completed radiotherapy, described as early (<6 weeks), delayed (6-15 weeks) and late (>15 weeks) reconstructions.Total flap loss was more common in irradiated cases (P = 0.035), among which flap failure increased with time elapsed from the last radiotherapy session to surgery (P = 0.021). Among 30 registered vascular complications, venous thrombosis was the most common type and increased in delayed, compared to early, reconstructions (P = 0.012). Increased salvage rates were observed when tPA was administered intraoperatively (P = 0.015).The present study indicates that previous radiotherapy is a risk factor for head and neck free flap failure, especially in delayed reconstructions. This may be linked to previous findings of impaired fibrinolysis in irradiated microvascular recipient veins, which is further supported by the beneficial effect of tPA during salvage surgery. We emphasize the importance of early reconstruction after radiotherapy and suggest that there is a role for fibrinolytic agents during free flap salvage surgery in previously irradiated subjects.

The repair of complex craniofacial bone defects is challenging and a successful result is dependent on the size of the defect, quality of the soft tissue covering the defect, and choice of reconstruction method. The objective of this study was to develop a bioactive cranial implant that could provide a permanent reconstructive solution to the patient by stimulating bone healing of the defect. In this paper the authors report on the feasibility and clinical results of using such a newly developed device for the repair of a large traumatic and therapyresistant cranial bone defect. The patient had undergone numerous attempts at repair, in which established methods had been tried without success. 273Abbreviations used in this paper: bPPi = bcalcium pyrophos phates; bTCP = btricalcium phosphate.

Therapeutic, III.

Tissue engineering of bone with hyaluronan-based hydrogel shows good healing of cranial defects, comparable with bone autografts. The hydrogel itself may represent a novel alternative to autologous bone transplants in craniofacial bone repair. The study also reveals a general superior healing capacity in the frontal bone as compared to parietal/temporal bones.