Reducing ischemia-reperfusion injury in rat island groin flaps by dexamethasone and BW755C

Despite the known effectiveness of anti-inflammatory therapy in reducing reperfusion injury, no studies to date involve the use of anti-inflammatory therapy in reducing ischemia-reperfusion injury in fasciocutaneous flaps. Dexamethasone (a phospholi-pase A₂ inhibitor) and specific cyclooxygenase and lipoxygenase inhibitors (indomethacin and BW755C) were administered to rats with ischemic island groin (fasciocutaneous) flaps. Significant improvement in ischemic flap survival was found with dexamethasone and BW755C. The mode of action of dexamethasone was not specifically investigated in our study; however, it may suppress neutrophil function and reduce ischemia-reperfusion injury in its shared ability with BW755C to reduce the formation of leukotrienes. Dexamethasone could be applied in the clinical setting to reduce ischemic flap loss by attenuating the systemic inflammatory response to reperfused ischemic-damaged tissueb.     

Temporal factors affecting the secondary critical ischemia of normothermic experimental skin flaps.

In free tissue transfer surgery all flaps are subjected to a primary ischemic episode prior to reperfusion. Some flaps may fail due to a second ischemic insult in the postoperative period. The maximum allowable time for salvage of such failing flaps is referred to as the secondary critical ischemia time. Unilateral abdominal island skin flaps based on the superficial inferior epigastric vessels were raised in 96 Sprague-Dawley rats. Animals were divided into 24 groups of four rats each. Normothermic ischemia was produced by applying microvascular clamps to the vascular pedicles. The flap groups were subjected to combinations of primary ischemia, reperfusion, and secondary ischemia. Flap survival was assessed on the seventh postoperative day. Flap survival decreases significantly with increased primary and/or secondary ischemia time and decreased reperfusion period. Moreover, a longer primary ischemia and/or shorter reperfusion decrease the tolerance of the flap to a second ischemic insult.     

Hemodynamics of the rodent abdominal skin flap following primary ischemia

The effect of varying periods of ischemia and reperfusion times on subsequent blood flow was studied in the rodent abdominal skin flap. Using perfusion fluorometry, measurements of blood flow were quantified in 60 Sprague-Dawley rats undergoing clamp-induced ischemic periods ranging from 0 to 6 hours and reperfusion times ranging from 2 to 8 hours. Flaps subjected to ischemia times of 0, 2, 4, or 6 hours require 8 hours of reperfusion time before reaching baseline levels of blood flow. Blood flow in flaps subjected to 6 hours of ischemia was statistically less than the flow in flaps ischemic for 0, 2, and 4 hours and was directly related to length of reperfusion. These results demonstrate that flap perfusion does not fully take place immediately after clamp release. The factors thought to be responsible for these findings and the implications for the design and interpretation of flap ischemia experiments are discussed.     

An integrated theory of the no-reflow phenomenon and the beneficial effect of vascular washout on no-reflow

OBJECTIVES: No-reflow is failure of perfusion in free tissue transfer despite adequate arterial inflow. The objectives of this study were to construct a theory of interactive mechanisms of the no-reflow phenomenon and to determine whether preischemic vascular washout could increase flap ischemia tolerance. STUDY DESIGN: The evidence for the role of various mechanisms in the development of no-reflow is reviewed, and an integrated network proposed. A rat-groin free flap model is used to test preischemic vascular washout with normal saline, heparinized normal saline, lactated Ringer's solution, Tis-U-Sol, and Viaspan. METHODS: The mean ischemia tolerance of this flap without any therapeutic intervention was first determined, using 22 animals. An additional 50 animals were used to compare with the control group the ischemia tolerance of flaps washed out with the above fluids before their ischemic period. RESULTS: The critical ischemia time 50 (time after which half of the flaps are expected to survive and half, die) of the untreated flap is 23.4 hours in this model (P<.05). Flaps washed out with normal saline or lactated Ringer's solution have significantly worse ischemia tolerance (P<.0001). Flaps washed out with Tis-U-Sol or Viaspan behave similarly to the control group (P>.57). Flaps receiving preischemic washout with heparinized normal saline (4,000 units/L) had a significantly better outcome than the control group (P<.027). CONCLUSIONS: Preischemic washout with normal saline, lactated Ringer's solution, or heparinized Tis-U-Sol is detrimental for flap survival after ischemia, Tis-U-Sol- and Viaspan-treated flaps do have ischemia tolerance similar to the control group, and flaps washed out with heparinized normal saline have a survival advantage in this model.     

Viability of skin flaps subjected to simultaneous chemical peel with occlusive taping

This study was undertaken to determine whether the application of a standardized chemical peel with an occlusive tape dressing to an acutely raised skin flap (as in combining rhytidectomy with chemical peel) affects skin flap viability. Thirty-six 4-cm x 4.cm dorsal skin flaps were raised on guinea pigs and sutured back into place. Eighteen of these flaps were simultaneously treated with a single application of Baker's solution and a 24-hour occlusive tape dressing. A mean of 3.1 cm² of the non-peeled flaps necrosed, compared with 6.3 cm² of the peeled flaps, a statistically significant increase in tissue loss in flaps that were simultaneously chemically peeled. We conclude that application of Baker's solution with an occlusive tape dressing to an acutely raised skin flap impairs skin flap viability and may result in skin flap necrosis.     

Effects of Activated Macrophages and Fibroblast Growth Factor on Random Skin Flap Survival in Swine

Objective: To examine the effect of application of activated autologous macrophages and basic fibro-blast growth factor (FGF) on random skin flap survival in swine. Design: A randomized nonblinded controlled trial. According to a standard design, six dorsally based, random-pattern skin flaps were raised in each of 12 Yorkshire pigs. Methods: Twenty-five milliliters of blood is harvested from each animal 20 to 24 hours prior to flap creation. Monocytes are isolated, placed in culture medium, and then activated by the addition of platelet-derived growth factor (PDGF) and tissue growth factor beta (TGF-β). Following an 18-hour incubation period, the monocytes are decanted and quantified, and their viability confirmed. These cells are then infused into the wound bed of the treatment flaps immediately following flap creation, and FGF is added prior to flap closure. The position of treatment and control flaps is systematically varied with regard to anterior-to-posterior and side-to-side flap positions within each animal. The area of superficial flap necrosis is evaluated on postoperative day 7, digitally scanned, and analyzed using graphics software. Control flaps are elevated similarly, but receive no placebo treatment. Results: Two-way analysis of variance (ANOVA) demonstrated nonsignificant differences between pig side and anterior, middle, and posterior flap positions within treatment and control flap groups. Using side and position pooled data, a one-way ANOVA showed no statistically significant differences between treatment and control flaps. Conclusions: The cellular and biochemical events following creation of a surgical wound are complex and incompletely understood. Our attempt to augment the natural role of the macrophage in wound healing by employing cytokines to activate these cells and to accelerate their arrival by implanting them into the wound bed failed to enhance flap survival. Further study is warranted to ascertain the details of wound healing, particularly with respect to cytokine concentrations and the timing of their roles, if we are to find a clinically applicable means of enhancing flap survival.     

Caspase inhibition enhances ischemic tolerance of fasciocutaneous flaps

OBJECTIVES/HYPOTHESIS: To demonstrate the significance of apoptosis in ischemia-reperfusion injury in revascularized fasciocutaneous flaps and test the hypothesis that pharmacologic inhibition of caspases prolongs the allowable primary ischemia time of these flaps. STUDY DESIGN: Animal study using the epigastric flap in adult male Sprague-Dawley rats. METHODS: Fifty-nine rats were treated with the caspase inhibitor (Q-VD-OPH) reconstituted in dimethylsulfoxide (DMSO) (n = 20, 8 mg/kg:0.8 mL/kg), DMSO alone (n = 19, 0.8 mL/kg), or saline (n = 20, 0.8 mL/kg). Treatment was given as a single intraperitoneal injection 30 minutes before starting primary ischemia. Epigastric flaps were subjected to increasing ischemia times followed by reperfusion. The flaps were harvested and analyzed 7 days later, and viability was assessed. Probit statistical analysis was used to determine the critical ischemia time. This was defined as the time point when 50% of the flaps in each group were expected to survive. RESULTS: The calculated critical ischemia times were 8.92 hours (95% confidence interval 7.19-10.47 h) for the saline group, 16.35 hours (95% confidence interval 11.82-19.89 h) for the DMSO group, and 21.73 hours (95% confidence interval 19.39-25.37 h) for the DMSO with Q-VD-OPH group. These differences were significantly different from each other. CONCLUSIONS: Pretreatment of fasciocutaneous flaps with a free radical scavenger alone or in combination with a caspase inhibitor significantly increases the flap's tolerance of primary ischemia. The added benefit of the caspase inhibitor suggests that apoptosis plays an important role in ischemia-reperfusion injury in soft tissue flaps.     

The effect of hydroxyl radical scavenging on acute axial-random skin flap survival

Dimethyl thiourea (DMTU), a known hydroxyl radical scavenger, was tested for its ability to improve survival in acute island skin flaps. Rats receiving 500 mg/kg DMTU 1 hour after flap elevation showed a 23.5% improved survival over saline controls. The role of the hydroxyl radical in ischemia/reperfusion injury, and its proposed mechanism, is discussed.     

Effects of Tisseel and FloSeal on primary ischemic time in a rat fasciocutaneous free flap model

OBJECTIVES: Free flaps are the technique of choice for reconstruction of defects resulting from extirpation of tumors of the head and neck. Advances in microsurgical technique have resulted in success rates of greater than 95%. Numerous intraoperative factors, ranging from technical issues to topically applied agents, can complicate the outcome of microsurgical free tissue transfer. Synthetic tissue adhesives and hemostatic agents are playing an ever-increasing role in reconstructive surgery. The safety of these factors in free flap surgery has not been ascertained. STUDY DESIGN: Animal Care Committee live rat model. METHODS: Male Sprague-Dawley rats were divided into three groups: group I, Control; group 2, FloSeal; group 3, Tisseel. In each group, a 3 x 6 cm ventral fasciocutaneous groin flap based on the left superficial epigastric artery was elevated and the experimental material applied beneath the flap and around the flap pedicle prior to suturing of the flap back to the wound bed. The experimental materials consisted of 0.2 mL saline in the control group, 0.5 mL FloSeal, and 0.2 mL Tisseel. In phase I of this study, the effect of each treatment on flap survival was assessed by survival at postoperative day 4. In phase II of the study, the effects of these agents on ischemic tolerance was investigated. Five rats in each treatment group were exposed to ischemic times of 6, 8, 10, and 12 hours. Survival of the flap was assessed 7 days after reversal of the ischemia. Probit curves and the critical ischemic time (CIT50) were calculated. RESULTS: All flaps survived the 2-hour period of ischemia and were viable at postoperative day 4. Flap survival from group 1 (Control), group 2 (FloSeal), and group 3 (Tisseel) at the various ischemic times was as follows: at 6 hours, 80%, 80%, and 80%, respectively; at 8 hours, 80%, 80%, 60%; at 10 hours, 60%, 33%, 40%; at 12 hours, 20%, 20%, 0%. The CIT50 for the Control, FloSeal, and Tisseel groups was 9.4, 9.0, and 7.0 hours, respectively.CONCLUSIONS FloSeal, a thrombin-based hemostatic agent, and Tisseel, a fibrin glue, displayed no adverse effect on flap survival in this model.     

Der epigastrisch adipokutane Lappen am Tiermodell zur Evaluierung der ischämischen Präkonditionierung

Introduction

Flap necrosis in ear, nose, and throat surgery, especially in high-risk groups, is not rare, but not all of the individual pathophysiological processes are known. The objective of this study was to establish an animal model to determine whether acute ischemic preconditioning, which has been reported to be successful in organ transplantation, will result in enhanced flap survival.

Methods and materials

Forty-two Wistar rats were divided into three experimental groups. An epigastric adipocutaneous flap, based on both superficial epigastric arteries and veins, was raised. The flap was either raised (control), clamped for 2 h (ischemic), or subjected to ischemia of 30 min, followed by 30 min of reperfusion and another 2 h of induced ischemia (IP). The mean flap necrosis area was assessed in all groups on the 5th postoperative day.

Results

All animals were doing well on the final day. The average necrosis in the ischemic group was significantly greater than in the control group. No significant superiority in the IP group was demonstrated.

Conclusion

The data show that the experimental animal model is practicable and that additional approaches to ischemic preconditioning should be verified.     

豚鼠脑缺血再灌注后听皮层内质网应激相关因子的表达及意义

目的：观察豚鼠脑缺血再灌注后葡萄糖结合蛋白（glucose－regulated protein,GRP78）、半胱氨酸天冬氨酸蛋白酶－12（caspase－12）在听皮层的表达,探讨内质网应激（endoplasmic reticulum stress,ERS）在脑缺血再灌注后听皮层神经元凋亡中的作用。方法选取健康豚鼠50只,随机分为5组：正常对照组、A组（缺血再灌注6 h）、B组（缺血再灌注12 h）、C组（缺血再灌注24 h）、D组（缺血再灌注72 h）。采用夹闭双侧颈总动脉的方法建立脑缺血再灌注损伤模型,分别在脑缺血再灌注后6、12、24、72 h行听性脑干反应（ABR）测试后处死各组豚鼠,应用 HE染色法观察听皮层神经元病理变化,免疫组化染色及 Western－blot 方法检测各组GRP78、caspase－12的表达。结果从正常对照组到B组豚鼠ABR反应阈值逐渐增加,从C 组到D组又逐渐下降,但D组仍比正常对照组高（P＜0．05）。HE染色示正常对照组听皮层神经元排列整齐,胞浆丰富,胞核大而圆,染色清晰;A、B、C、D组听皮层神经元均有不同程度的数量减少,且体积萎缩,胞核固缩,碎裂,核仁消失。免疫组化染色及 Western－blot示正常对照组 GRP78、caspase－12蛋白仅有微量或少量表达,缺血再灌注后6 h,二者表达开始上调,至12 h GRP78表达达到高峰,12 h后逐渐降低,各组之间差异均有统计学意义（P＜0．05）。caspase－12表达24 h达到峰值,后逐渐下降,缺血再灌注6 h组与12 h组间差异无统计学意义,其余各组间差异均有统计学意义（P＜0．05）。结论脑缺血再灌注损伤可诱发内质网应激,使GRP78、caspase－12表达增加,GRP78、caspase－12可能参与了ERS介导的听皮层神经元细胞凋亡过程。     

A compendium of intranasal flaps

The reconstructive surgeon is frequently called upon to repair intranasal defects which require the use of grafts and/or flaps. In general, flaps are difficult to design and utilize because of 1. limited intranasal exposure and 2. the complex design requirements for movement of the flap through three dimensions. Intranasal exposure is increased by the transoral premaxillary approach, the lateral alotomy, the lateral rhinotomy, the transethmoid, and the open rhinoplasty. The flaps to be designed all utilize the basic principles for skin flaps. However in contrast to movement on a relatively two-dimensional surface, they frequently require movement in the three dimensions, i.e., from the floor of the nose up to the septum, from the side to the center, etc. We review the following flaps: 1. mucoperichondrial advancement and rotation flaps of the septum, 2. composite septal flap, 3. inferior turbinnte flaps, 4. nasal floor mucoperiosteal flaps, 5. middle turbinate flaps, 6. composite lateral cartilage flaps, 7. buccal sulcus flaps, and 8. nasolabial flaps.     

内质网应激反应对豚鼠脑缺血再灌注后听皮质区损伤的作用

目的　观察豚鼠脑缺血再灌注后需肌醇酶1(inositol requiring enzyme 1,IRE1）、X盒结合蛋白1(Xbox binding protein 1,XBP-1）在其听皮层的反应以及血 液中C反应蛋白（C reactive protein,CRP）和免疫球蛋白(immunoglobulin M,IgM）的变化,探讨内质网应激及血液免疫反应在脑缺血再灌注后听皮层神经元凋亡中的作用。方法　选取健康豚鼠20只,随机分为5组,每组各4只,分别为正常对照组、缺血15 min组、缺血再灌注6 h组、缺血再灌注24 h组及缺血再灌注7 d组。后四组在相同条件下采用夹闭双侧颈总动脉的方法来建立脑缺血再灌注损伤模型,对照组不予手术。缺血15 min组术后马上行听性脑干反应(ABR)测试,其余实验组待再灌注至对应的时间点后行ABR测试。心脏采血酶标记免疫吸附 (enzymelinked immunosorbent assay,ELISA）检测血液CRP和IgM的浓度。断头取脑用免疫组织化学的方法测定IRE1、XBP-1表达。结果　ABR测试对照组为（10.0±2.47）dB SPL,缺血15 min组为（15±1.56）dB SPL,缺血再灌注6 h组为（30±2.03）dB SPL,缺血再灌注24 h组为（30±1.67）dB SPL,缺血再灌注7 d组为（15±1.14）dB SPL。缺血再灌注6 h组与24 h组行t 检验,无显著统计学差异,其余各组行方差分析,均有统计学差异（F =170.631,P <0.01）。ELISA法检测CRP对照组为（1198.96±50.81）μmol/ml,缺血15 min组为（1270.70± 34.76）μmol/ml,缺血再灌注6 h组为（1467.80±73.67）μmol/ml,缺血再灌注24 h组为（1352.83±175.71）μmol/ml,缺血再灌注7 d组为（1252.56±41.32）μmol/ml。各实验组行方差分析均有统计学差异（F =6.564,P <0.01）。IgM对照组为（987.32±39.13）μmol/ml,缺血15 min组为（1064.90±39.78）μmol/ml,缺血再灌注6 h组为（1118.03±57.75）μmol/ml,缺血再灌注24 h组为（1122.43±55.40）μmol/ml,缺血再灌注7 d组为（1010.70±55.95）μmol/ml。缺血再灌注6 h与24 h组行t检验无显著差异,其余各组行方差分析均有统计学差异（F =7.413,P <0.01）。HE染色显示各实验组凋亡细胞数 目不等,对照组为2.6±1.13,缺血15 min组为14.1±2.71,缺血再灌注6 h组为24.9±2.20,缺血再灌注24 h组为19.3±1.46,缺血再灌注7 d组为9.4±1.17。各实验组行方差分析均有显著差异（F =109.666,P <0.01）。免疫组化结果显示各组IRE1、XBP-1均有显色。 IRE1阳性颗粒数对照组为9.4±1.56,缺血15 min组为25.6±1.58,缺血再灌注6 h组为60.3±1.57,缺血再灌注24 h组为42.2±2.13,缺血再灌注7 d组为18.3±1.59;各实验组行方差分析均有显著差异（F =709.750,P <0.01）;XBP-1阳性颗粒数对照组为10.6±1.24,缺血15 min组为24.2±1.52,缺血再灌注6 h组为61.4±1.7,缺血再灌注24 h组为41.1±2.38,缺血再灌注7 d组为18.9±1.59;各实验组行方差分析均有显著差异（F =682.737,P <0.01）;IRE1与细胞凋亡率成正相关（r =0.947,P =0.000）;XBP-1与细胞凋亡率成正相关 （r =0.933,P =0.000）;CRP与IRE1成正相关（r =0.747,P =0.000）;CRP与细胞凋亡率成正相关（r = 0.755,P =0.000）;IgM与IRE1成正相关（r=0.695,P =0.000）;IgM与细胞凋亡率成正相关（r =0.765,P =0.000）。结论　在脑缺血再灌注损伤中,听皮层组织IRE1α、XBP1蛋白高表达,提示内质网应激参与了脑缺血再灌注损伤神经元细胞凋亡的发生发展,IRE1α和XBP1介导的信号转导通路是内质网应激导致脑缺血再灌注损伤神经元细胞凋亡的机制之一,脑缺血导致的听觉受损又有可能引起血液免疫学改变,内质网应激反应激发并加强了免疫炎性反应。     

Green light photoplethysmography monitoring of free flaps

BACKGROUND: Monitoring strategies have been developed to address the issue of detecting postoperative free flap ischemia in an effort to permit intervention and flap salvage. No one existing noninvasive method has been widely accepted in a clinical setting. Green light photoplethysmography (GLP) uses a diode to transmit green light into a tissue. Reflected light from hemoglobin in dermal capillary red blood cells is analyzed as light intensity along a frequency spectrum. A pure peak signal (1-2 Hz) is identified and provides a way to distinguish between perfused and nonperfused tissue. DESIGN: Prospective, blinded comparison. SUBJECTS: Sixty of 72 consecutive patients considered for free flap reconstruction were enrolled in a protocol to evaluate the efficacy of GLP. INTERVENTION: After free flap elevation, but before pedicle ligation, 120-second baseline measurements were obtained; 120-second measurements then occurred 5 minutes after the onset or release of individual venous or arterial occlusion. Signals were processed by fast Fourier transfer; a mean alternating current-direct current (AC/ DC) ratio was cultivated for each signal. All data were analyzed in a blinded fashion. RESULTS: The AC/DC ratio of GLP was statistically significant across all flap perfusion states (P<.001). Each condition resulted in a unique GLP signal within 5 minutes of manipulation of each vessel. CONCLUSIONS: Green light photoplethysmography with AC/DC ratio analysis provides a rapid, precise method with which to determine flap ischemia and can differentiate venous compromised and arterial compromised flaps almost immediately after the onset of an ischemic insult. It may provide a clinically useful tool for postoperative free flap monitoring.     

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

BACKGROUND: Photodynamic therapy (PDT) may be used as an adjuvant intraoperative therapy to improve locoregional control. PDT has been shown to delay wound healing. This raises concern about PDTs effect on survival of fasciocutaneous flaps. OBJECTIVE: Evaluate the effect of 1) PDT on the critical ischemic time in a rat fasciocutaneous flap model and 2) photosensitizer activation 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. Animals were randomly divided into five groups: ischemia only, group I; light treatment to wound bed, group II; Photofrin before surgery with the flap elevated without a fiber optic head light, group III, or with a headlight, group IV; Photofrin prior to surgery with light treatment to the wound bed, group V. Flap survival was assessed on postoperative day 7. RESULTS: The critical 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 the critical primary ischemic time when a fiber optic headlight was used (group III vs. group IV). CONCLUSION: Intraoperative PDT significantly reduces the critical primary ischemic time of the rat fasciocutaneous flap. White light illumination of the operative field does not result in photosensitizer activation and has no effect on the critical primary ischemic time.     

The failing flap in facial plastic and reconstructive surgery: Role of the medicinal leech

Objective: To review the use of the medicinal leech, Hirudo medicinalis, in salvaging the failing, venous-congested flap. A protocol for the use of leeches is presented. Four illustrative cases of failing flaps (pectoralis major, midline forehead, and temporalis) are presented. Study Design: Literature review comprised of MEDLINE search 1965 to present. Retrospective review of four cases involving the management of the failing, venous-congested flap. Methods: A retrospective review of four cases of failing, venous-congested flaps was performed. Results: The authors' experience, as well as the data from the reviewed medical literature, demonstrates the importance of early intervention in order to salvage the failing, venous-congested flap. Leeches are an immediate and efficacious treatment option. Conclusions: 1. Review of the literature indicates that the survival of the compromised, venous-congested flap is improved by early intervention with the medicinal leech. H medicinalis injects salivary components that inhibit both platelet aggregation and the coagulation cascade. The flap is decongested initially as the leech extracts blood and is further decongested as the bite wound oozes after the leech detaches. 2. When a flap begins to fail, salvage of that flap demands early recognition of reversible processes, such as venous congestion. The surgeon must be familiar with the use of leeches and should consider their use early, since flaps demonstrate significantly decreased survival after 3 hours if venous congestion is not relieved. In the four cases presented, a standardized protocol facilitated early leech use and provided for the psychological preparation of the patient, availability of leeches, and an antibiotic prophylaxis regimen. 3. The complications associated with leech use can be minimized with antibiotic therapy, wound care, and hematocrit monitoring. 4. The use of the medicinal leech for salvage of the venous-congested flap is a safe, efficacious, economical, and well-tolerated intervention.     

A Prospective Comparison of Scalpel Versus Bipolar Scissors in the Elevation of Radial Forearm Fasciocutaneous Free Flaps

Objectives/Hypothesis The radial forearm fasciocutaneous free flap has become the workhorse for reconstruction of head and neck ablative defects. A location distal to the head and neck allows this flap to be elevated concurrent with the ablation. Most commonly, the flap is elevated under tourniquet control. This involves a primary ischemic insult with a certain amount of hemorrhage after the tourniquet is released. Bipolar scissors are a new method of dissection. They may allow for a speedier dissection with a concomitant decrease in ischemic time. Their hemostatic properties may control hemorrhage after use of the tourniquet. Study Design A prospective study of patients undergoing radial forearm free flaps over a 12‐month period at a tertiary care referral center was undertaken. Results Forty patients were entered into the study, flaps were elevated with scalpel (20) and with bipolar scissors (20). Mean time under tourniquet was 39 minutes (range, 30–56 min) with scalpel compared with 27 minutes (range, 21–31 min) with bipolar scissors (P <.001). Total mean time of elevation (including control of hemostasis and pedicle dissection) for scalpel elevation was 50 minutes (range, 35–61 min) compared with 32 minutes (range, 20–41 min) for bipolar scissors elevation (P <.001). Mean blood loss was 46 mL (range, 15–110 mL) in the scalpel elevation group compared with 14 mL (range, 0–50 mL) in the bipolar scissors elevation group (P <.001). Complications at the donor site were equal between groups. Conclusions Bipolar scissors are a safe, efficient method for elevating radial forearm free flaps.     

心钠素对耳蜗缺血再灌注损伤的影响

目的观察心钠素对豚鼠耳蜗缺血再灌注损伤的影响。方法将豚鼠分为4组：实验组（A1、B1）及对照组（A2、B2）。采用造血栓后溶栓的方法制备耳蜗缺血再灌注模型。实验组A1在建模前10min静脉注射心钠素，实验组B1在再灌注即刻静脉注射心钠素，对照组（A2、B2）在相应时间静脉注射等量生理盐水。实验过程中采用激光多普勒血流量仪监测耳蜗血流量（cochlear blood flow，CoBF）并测定豚鼠听性脑干反应（auditory brainstem response，ABR）值。结果缺血前实验组A1的CoBF较对照组A2高，再灌注后至实验结束，2组CoBF值未见明显差别。实验组B1和对照组B2用药前的CoBF无明显差别，再灌注后对照组B2恢复到实验开始时的70％左右，而实验组B1恢复到实验开始时相同水平。缺血前4组听阈差异无统计学意义。缺血30min时，实验组A1的听阈较对照组A2低（t=7．761，P〈0．05）。实验组B1和对照组B2听阈差异无统计学意义。再灌注30min和60min时，实验组A1与对照组A2差异无统计学意义。实验组B1比对照组B2显著降低（t值分别为9．846和19．242，P值均〈0．05）。结论缺血再灌注后即刻应用心钠素，可以减轻耳蜗的缺血再灌注损伤，可以在增加耳蜗血流的同时降低听反应阈。为临床内耳微循环障碍疾病提供一种新的药物治疗方法。     

Effect of photodynamic therapy on revascularization of fasciocutaneous flaps

OBJECTIVE: Photodynamic therapy (PDT) may be used as an adjuvant intraoperative treatment to improve locoregional control. PDT has been shown both to delay wound healing and to have a deleterious effect on flap survival after a primary ischemic insult. This delay in wound healing may make the flap dependent on its pedicled blood supply for a prolonged period. Long-term flap loss may be experienced. The effect of PDT on flap revascularization, with subsequent dependence on its vascular pedicle, is evaluated. STUDY DESIGN: Randomized controlled trial using a rodent model. METHODS: A rat fasciocutaneous flap was used. Study groups were as follows: group I received no treatment; group II received treatment with 630-nm light; groups IH and IV were given Photofrin (in group III, loupes without a fiberoptic light source were used for flap elevation, and in group IV, light source was employed); and group V was given Photofrin and 630-nm light. Primary ischemic times of 2 or 4 hours were used. Vascular pedicles were ligated on postoperative day (POD) 5, 6, or 7, and percentage of flap survival was evaluated 7 days later. RESULTS: With 2 hours of ischemia, revascularization was decreased in the PDT group on POD 6 (P < .05) and on day 7 (P < .005) when compared with the other groups. With 4 hours of ischemia, revascularization was decreased in the PDT group on PODs 5 (P < .001), 6 (P < .01), and 7 (P < .005). CONCLUSION: Intraoperative PDT decreases revascularization of a rat fasciocutaneous flap.     

Head and neck reconstruction with free flaps: a report on 213 cases

The aim of this retrospective study is to review the experience of our institution in performing microvascular head and neck reconstruction between 2000 and 2004. During this period, 213 free flaps, including 146 radial forearm free flaps, 60 fibular flaps and 7 scapular flaps, were performed. Free flap success rate and complications were reported. The pre-treatment factors influencing these results were subsequently analyzed. Functional and aesthetic outcomes were evaluated by the same clinician. There were 14 free flap failures, giving an overall free flap success rate of 93.4%. Salvage surgery for recurrent cancer was the only factor correlated with a higher risk of free flap failure (P = 0.0004). The local complication rate was 20.9%. High level of comorbidity (P = 0.009), salvage surgery for recurrent cancer (P = 0.03) and hypopharyngeal surgery (P = 0.002) were associated with a higher risk of local complications. An unrestricted oral diet and an intelligible speech were recovered by respectively 76 and 88% of the patients. Microvascular free flaps represent an essential and reliable technique for head neck reconstruction and allow satisfactory functional results.