Chapter 6 Discussion Arginine supplementation significantly increased blood flow in zone IV, the most distal part with less collateral circulation and usually the area at risk for insufficient perfusion and subsequent flap loss. Partial flap loss was observed mainly in the placebo group, and flap complications were more severe. Use of the Model Recent studies have demonstrated that despite a high success rate in free flap surgery, complications still are quite common.25 Even with removal of zone III and zone IV as in bilateral deep inferior epigastric artery perforator (DIEP) flap reconstruction, partial flap loss and/or fat necrosis still occurs. In addition, fat necrosis can lead to a palpable lump that may mimic breast cancer recurrence. This causes extra emotional burden and may lead to secondary corrective surgery. Even in zone I, which is the best perfused zone, fat necrosis can occur.26 Therefore, studies to further improve these results are needed. Possible flaws in the model Most recent literature attributes fat necrosis and flap loss to merely venous congestion in zone IV.27,28 There is a variety in perforator diameter, midline crossover, and deep/superficial venous communications. Therefore, in some cases, the selected perforating vein may not adequately drain the flap and may lead to fat necrosis and/or flap loss.29,30 However, discarding zone IV does not eliminate the chance of flap complications. Additional venous anastomosis to decrease venous congestion has not been shown to decrease fat necrosis thus far.27 This suggests that fat necrosis has a multifactor cause and that ischemia‐reperfusion may be negated as a cause in clinical studies so far. The net result of venous stasis is an increase of the ischemia period in distal parts of the flap. After opening the choke vessels, the following ischemia‐ reperfusion injury is more severe. The effect of various strategies for reducing ischemia‐reperfusion injury and (partial) flap loss with experimental models in the literature supports this theory. How to reduce reperfusion injury Reperfusion injury has wide clinical relevance. It influences the outcome, not solely in free flap (autologous) transplantation in reconstructive surgery, but also in patients with myocardial infarction, stroke, organ transplantation, cardiovascular surgery, and reimplantation of limbs or digits. Despite small clinical studies showing variable success in the treatment of reperfusion injury, there is presently no well‐validated intervention that reduces the effect of ischemia‐reperfusion injury.31,32 94
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