Prior Radiotherapy

Radiotherapy and chemoradiotherapy are increasingly used in the treatment of locally advanced head and neck cancer in an attempt to preserve organ function or to control persistent or recurrent disease. Previous radiotherapy can cause thickening and perivascular fibrosis in the irradiated field. The vascular changes induced by radiation include transmural fibrosis, formation of microthrombi, atheromatous plaque deposition, and endarteritis obliterans.38-40 Because of these changes, irradiated vessels can have lower flow rates than nonirradiated vessels of similar diameter and may be more susceptible to spasm. These findings have led some investigators to conclude that irradiated vessels are not well suited for microvascular surgery. Despite these changes, studies have not shown detrimental effects of previous irradiation on anastomotic patency rates or postoperative free flap complications.38,40-42

In a study of 42 patients undergoing free flap reconstruction, Kiener et al.41 noted no differences in total flap loss or major complications between groups of previously irradiated and nonirradiated patients. A larger study by Bengtson et al.42 of 354 free flap patients also showed no differences in total flap loss (5.3% vs 5%), partial flap loss, or major wound complications (16% vs 11%) between previously irradiated and nonirra-diated patients. The overall complication rates of free flaps in this study were still significantly less than for PMC flap reconstruction in similarly irradiated fields (16% vs 35%).43 Unlike regional flaps, free flaps, with their independent blood supply, do not have any limitations on the amount of well-vascularized tissue that can be brought into an irradiated area.

These and other studies confirm our own experience that previous radiation in and of itself does not increase failure rates of free flaps and should not be a contraindication to reconstruc tion with a free flap. Our approach has been to perform anastomoses into the largest available vessels (usually the external carotid and internal jugular vein) which have the greatest flow and are least prone to spasms, thus minimizing the effects of radiation on flap survival. Meticulous technique in performing the anastomosis is even more important in the irradiated field as our experience confirms the finding of others that any acute intraoperative complications (thrombosis, kinking, length discrepancy) requiring revision significantly increases flap failure.42

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