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Flap Survival (flap + survival)
Selected AbstractsFunctional reconstruction of complex lip and cheek defect with free composite anterolateral thigh flap and vascularized fascia,HEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 8 2008Yur-Ren Kuo MD Abstract Background. Extensive composite defects involving the lip and cheek present difficult reconstructive challenges. This study presents a technique using anterolateral thigh (ALT) flaps with vascularized fascia for large complex oral sphincter defect reconstruction. Methods. Fifteen patients who had undergone oral cancer ablation were enrolled in the study. The average area of intraoral lining and cheek,lip skin defects was 96.9 cm2. Upper-lip defects ranged 0% to 60%, and lower-lip defects ranged 20% to 80%. Skin and intraoral lining defects were replaced by an ALT fasciacutaneous flap. The vascularized fascia of the flap was used to provide lip suspension. Results. Flap survival was 100%. All but 1 patient had good static suspension. Nine patients had adequate oral competence without drooling, but 6 had occasional oral incontinence. All patients achieved an acceptable appearance. Conclusions. For extensive cheek,lip composite defects, ALT flap together with vascularized fascia has proven to be a useful option for functional reconstruction. © 2008 Wiley Periodicals, Inc. Head Neck 2008 [source] Non-viral VEGF165 gene therapy , magnetofection of acoustically active magnetic lipospheres (,magnetobubbles') increases tissue survival in an oversized skin flap modelJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 3 2010Thomas Holzbach Abstract Adenoviral transduction of the VEGF gene in an oversized skin flap increases flap survival and perfusion. In this study, we investigated the potential of magnetofection of magnetic lipospheres containing VEGF165 -cDNA on survival and perfusion of ischemic skin flaps and evaluated the method with respect to the significance of applied magnetic field and ultrasound. We prepared perfluoropropane-filled magnetic lipospheres (,magnetobubbles') from Tween60-coated magnetic nanoparticles, Metafectene, soybean-oil and cDNA and studied the effect in an oversized random-pattern-flap model in the rats (n= 46). VEGF-cDNA-magnetobubbles were administered under a magnetic field with simultaneously applied ultrasound, under magnetic field alone and with applied ultrasound alone. Therapy was conducted 7 days pre-operative. Flap survival and necrosis were measured 7 days post-operatively. Flap perfusion, VEGF-protein concentration in target and surrounding tissue, formation and appearance of new vessels were analysed additionally. Magnetofection with VEGF-cDNA-magnetobubbles presented an increased flap survival of 50% and increased flap perfusion (P < 0.05). Without ultrasound and without magnetic field, the effect is weakened. VEGF concentration in target tissue was elevated (P < 0.05), while underlying muscle was not affected. Our results demonstrate the successful VEGF gene therapy by means of magnetobubble magnetofection. Here, the method of magnetofection of magnetic lipospheres is equally efficient as adenoviral transduction, but has a presumable superior safety profile. [source] Effects of Tisseel and FloSeal on Primary Ischemic Time in a Rat Fasciocutaneous Free Flap Model,THE LARYNGOSCOPE, Issue 2 2004Aaron W. Partsafas BS Abstract 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 × 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. [source] Efficacy of the Flashlamp-Pumped Pulsed-Dye Laser in Nonsurgical Delay of Skin FlapsDERMATOLOGIC SURGERY, Issue 7 2003Ali Riza Erçöçen MD Objective. The purpose of this article was to determine the effectiveness of laser delay by use of the flashlamp-pumped pulsed-dye laser operating at a wavelength of 585 nm; to elucidate the comparable or dissimilar macroscopic, microscopic, and hemodynamic changes between laser and surgical delay methods; and to clarify the possible mechanisms underlying the delay effect of laser. Methods. A standardized caudally based random dorsal rat flap model was used in this study: Acute random skin flaps served as control subjects (group 1). Surgical delay was employed by incision of lateral longitudinal borders both without (group 2) and with (group 3) undermining, and laser delay methods were performed by laser irradiation of both lateral longitudinal borders (group 4) and the entire surface (group 5) of the proposed flap. Evaluation was done by histologic examination, India ink injection, laser Doppler perfusion imaging, and measurement of flap survival. Results. Histologically, dilation and hypertrophy of subpapillary and subdermal vessels were evident in groups 2, 3, and 4; on the other hand, degranulation of mast cells in the vicinity of occluded vessels at the 1st hour of laser delay and a striking mast cell proliferation and degranulation in association with newly formed vessels (angiogenesis) at the 14th day of laser delay were prominent in group 5. India ink injections revealed longitudinally arranged large-caliber vessels and cross-filling between the vessels of adjacent territories in groups, 2, 3, and 4, but only small-caliber vessels in group 5. Compared with the acute flaps, both surgical and laser delay significantly increased the mean flap perfusion to the maximal levels after a 14-day delay period, and all delay procedures improved flap survival; the most significant increase in surviving area was observed in group 3, whereas the less significant increase in surviving area was in group 5. Conclusion. This study demonstrates that laser delay is as effective as surgical delay and that laser delay by lasering lateral borders leads to dilation and longitudinal rearrangement of the existing vessels rather than angiogenesis, whereas laser delay by lasering the entire surface results in delay effect by inducing angiogenesis due to activation and degranulation of the mast cells. [source] Enhancing the outcome of free latissimus dorsi muscle flap reconstruction of scalp defectsHEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 1 2004FRCS(C), Joan E. Lipa MD Abstract Background. Reconstruction of scalp and calvarial defects after tumor ablation frequently requires prosthetic cranioplasty and cutaneous coverage. Furthermore, patients often have advanced disease and receive perioperative radiotherapy. We evaluated the complications of scalp reconstruction with a free latissimus dorsi muscle flap in this setting. Methods. The complications and the oncologic and aesthetic outcomes of six consecutive scalp reconstructions with a free latissimus dorsi muscle flap and skin graft in five patients with advanced cancer were retrospectively evaluated. Patient, tumor, defect, reconstructive, and other treatment characteristics were reviewed. Reconstructive and perioperative techniques intended to improve flap survival and aesthetic outcome and reduce complications in these patients. Results. All patients (52,76 years old) had recurrent tumors (sarcoma, melanoma, or squamous cell carcinoma) and received postoperative radiotherapy. The mean scalp defect size was 367 cm2, and partial-thickness or full-thickness calvarial resection was required in all six cases. No vein grafts were needed. The mean follow-up period and disease-free survival time were 18 and 13 months, respectively. Three patients died of their disease, and two survived disease free. There were no flap failures or dehiscences. Complications consisted of donor site seroma in two patients; partial skin graft loss in one patient; and radiation burns to the flap, face, and ears in one patient. Scalp contour and aesthetic outcome were very good in all cases except for the one case with radiation burns. Conclusions. Good outcomes were achieved using a free latissimus dorsi muscle flap with a skin graft for flap reconstruction in elderly patients with advanced recurrent cancers who received perioperative radiotherapy. Several technical aspects of the reconstruction technique intended to enhance the functional and aesthetic outcome and/or reduce complications were believed to have contributed to the good results. © 2004 Wiley Periodicals, Inc. Head Neck26: 46,53, 2004 [source] Non-viral VEGF165 gene therapy , magnetofection of acoustically active magnetic lipospheres (,magnetobubbles') increases tissue survival in an oversized skin flap modelJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 3 2010Thomas Holzbach Abstract Adenoviral transduction of the VEGF gene in an oversized skin flap increases flap survival and perfusion. In this study, we investigated the potential of magnetofection of magnetic lipospheres containing VEGF165 -cDNA on survival and perfusion of ischemic skin flaps and evaluated the method with respect to the significance of applied magnetic field and ultrasound. We prepared perfluoropropane-filled magnetic lipospheres (,magnetobubbles') from Tween60-coated magnetic nanoparticles, Metafectene, soybean-oil and cDNA and studied the effect in an oversized random-pattern-flap model in the rats (n= 46). VEGF-cDNA-magnetobubbles were administered under a magnetic field with simultaneously applied ultrasound, under magnetic field alone and with applied ultrasound alone. Therapy was conducted 7 days pre-operative. Flap survival and necrosis were measured 7 days post-operatively. Flap perfusion, VEGF-protein concentration in target and surrounding tissue, formation and appearance of new vessels were analysed additionally. Magnetofection with VEGF-cDNA-magnetobubbles presented an increased flap survival of 50% and increased flap perfusion (P < 0.05). Without ultrasound and without magnetic field, the effect is weakened. VEGF concentration in target tissue was elevated (P < 0.05), while underlying muscle was not affected. Our results demonstrate the successful VEGF gene therapy by means of magnetobubble magnetofection. Here, the method of magnetofection of magnetic lipospheres is equally efficient as adenoviral transduction, but has a presumable superior safety profile. [source] Simultaneous use of bilateral caudal superficial epigastric axial pattern flaps for wound closure in a dogJOURNAL OF SMALL ANIMAL PRACTICE, Issue 12 2003P. D. Mayhew A neutered male German shorthaired pointer sustained severe bite wounds to the left caudal flank and thigh area. Thorough wound lavage and debrldement was performed immediately and also three days after presentation. Daily wound dressing resulted in the production of a mature granulation tissue bed. Prior to wound closure, colour flow Doppler ultrasonography was used to confirm blood flow through the right and left caudal superficial epigastric arteries and veins. Sixteen days after presentation, right and left caudal superficial epigastric axial pattern flaps were simultaneously elevated to cover the defect. The right flap was elevated as an island flap, rotated 120° and used to cover the caudodorsal aspect of the defect. The left flap was elevated and rotated dorsally to cover the cranioventral aspect of the defect. Ninety per cent wound coverage was achieved and flap survival was total. The donor site defect was closed primarily and no dehiscence occurred. Three months postsurgery, the entire defect was closed and limb function was normal. [source] A single center comparison of one versus two venous anastomoses in 564 consecutive DIEP flaps: Investigating the effect on venous congestion and flap survival,MICROSURGERY, Issue 3 2010Morteza Enajat M.D. Background: Venous complications have been reported as the more frequently encountered vascular complications seen in the transfer of deep inferior epigastric artery (DIEA) perforator (DIEP) flaps, with a variety of techniques described for augmenting the venous drainage of these flaps to minimize venous congestion. The benefits of such techniques have not been shown to be of clinical benefit on a large scale due to the small number of cases in published series. Methods: A retrospective study of 564 consecutive DIEP flaps at a single institution was undertaken, comparing the prospective use of one venous anastomosis (273 cases) to two anastomoses (291 cases). The secondary donor vein comprised a second DIEA venae commitante in 7.9% of cases and a superficial inferior epigastric vein (SIEV) in 92.1%. Clinical outcomes were assessed, in particular rates of venous congestion. Results: The use of two venous anastomoses resulted in a significant reduction in the number of cases of venous congestion to zero (0 vs. 7, P = 0.006). All other outcomes were similar between groups. Notably, the use of a secondary vein did not result in any significant increase in operative time (385 minutes vs. 383 minutes, P = 0.57). Conclusions: The use of a secondary vein in the drainage of a DIEP flap can significantly reduce the incidence of venous congestion, with no detriment to complication rates. Consideration of incorporating both the superficial and deep venous systems is an approach that may further improve the venous drainage of the flap. © 2009 Wiley-Liss, Inc. Microsurgery, 2010. [source] Assessment of the patency of microvascular anastomoses using microscope-integrated near-infrared angiography: A preliminary studyMICROSURGERY, Issue 7 2009Charlotte Holm M.D., Ph.D. Background: Technical problems at the site of the anastomosis compromise an underappreciated proportion of microsurgical free tissue transfers. Intraoperative identification of technical errors may be able to prevent reexploration surgery and early flap failure. We report the first human study on a new microscope-integrated fluorescence angiography technique, which allows for intraoperative imaging of the anastomotic site. Methods: Fifty consecutive patients undergoing reconstructive microsurgical procedures were enrolled in the study. Intraoperative near infrared indocyanine green videoangiography (ICGA) was performed on all microsurgical anastomoses, after they had been assessed by the operating surgeon by conventional clinical patency tests. Anastomoses deemed to be occluded by the ICG-angiography were intraoperatively revised, and the result of revision was compared with angiographic findings. Results: In 11/50 (22%) of patients, where the surgeon had classified the anastomoses as patent, microangiography identified a total luminal occlusion (six) and/or significant alterations in blood flow (five), potentially predisposing toward postoperative flap failure. Intraoperative revision confirmed angiographic findings in 100% of cases, and was always associated with flap survival. The decision not to revise despite anastomotic occlusion by the intraoperative angiogram was always followed by flap loss or early reexploration. A delayed return of venous blood from the flap predisposed toward postoperative flap failure. Conclusions: Hand-sewn anastomoses are subject to technical errors, and conventional patency tests have a low sensitivity for revealing anastomotic failure. Microscope integrated microangiography is an excellent method for identifying significant anastomotic problems, which would have otherwise gone unnoticed. The potential impact on early flap failure and reexploration surgery is considerable. © 2009 Wiley-Liss, Inc. Microsurgery 2009. [source] Establishing the case for CT angiography in the preoperative imaging of abdominal wall perforatorsMICROSURGERY, Issue 5 2008BMedSc, PGDipSurgAnat, W. M. Rozen MBBS Preoperative imaging of the donor site vasculature for deep inferior epigastric artery (DIEA) perforator flaps and other abdominal wall reconstructive flaps has become more commonplace. Abdominal wall computed tomography angiography (CTA) has been described as the most accurate and reproducible modality available for demonstrating the location, size, and course of individual perforators. We drew on our experience of 75 consecutive patients planned for DIEA-based flap surgery undertaking CTA at a single institution. Seven of these cases have been reported to highlight the utility of CTA for preoperative planning, emphasizing the unique information supplied by CTA that may influence operative outcome. Among all cases that underwent preoperative imaging with CTA, there was 100% flap survival, with no partial or complete flap necrosis. We found that in three of the cases described, the choice of operation was necessarily selected based on CTA findings (DIEA perforator flap, transverse rectus abdominis myocutaneous flap, and superficial superior epigastric artery flap). In addition, three cases demonstrate that CTA findings may dictate the decision to operate at all, and one case demonstrates the utility of CTA for evaluating the entire abdominal contents for comorbid conditions. Our experience with CTA for abdominal wall perforator mapping has been highly beneficial. CTA may guide operative technique and improve perforator selection in uncomplicated cases, and in difficult cases it can guide the most appropriate operation or indeed if an operation is appropriate at all. This is particularly the case in the setting of comorbidities or previous abdominal surgery. © 2008 Wiley-Liss, Inc. Microsurgery, 2008. [source] Reliability of free-flap coverage in diabetic foot ulcersMICROSURGERY, Issue 2 2005Ömer Özkan M.D. As microsurgery advances, microsurgical free-tissue transfers have become the reconstructive method of choice over staged or primary amputation, and enabling independent ambulation in difficult lower-extremity wounds. In this report, we present our experiences with free-tissue transfer for the reconstruction of soft-tissue defects in 13 diabetic foot ulcers. Following radical debridement, soft-tissue reconstruction was achieved in the following ways: anterolateral thigh fasciocutaneous flap in 5 patients, radial forearm fasciocutaneous flap in 3 patients, lateral arm fasciocutaneous flap in 1 patient, gracilis musculocutaneous flap in 1 patient, tensor fascia latae flap in 1 patient, deep inferior epigastric perforator flap in 1 patient, and a parascapular flap in the remaining patient. In 8 cases, diabetic wounds were in the foot, while wounds were at the level of the lower leg in the remaining patients. In all patients, vascular patency was confirmed by the Doppler technique. In suspicious cases, arteriography was then performed. While all flaps survived well in the postoperative period, one patient died from cardiopulmonary problems on postoperative day 16 in an intensive care unit. Amputation was necessary in the early postoperative period because of healing problems. In the remaining 10 cases, all flaps survived intact. In one case, arterial revision was performed successfully. The ultimate limb salvage rate was 83% for the 12 patients. Independent ambulation was achieved in these cases. During the follow-up period of 8 months to 2 years, no ulcer recurrence was noted, and no revascularization or vascular bypass surgery was needed before or after the free-tissue transfers. The authors conclude that free-tissue transfer for diabetic foot ulcers is a reliable procedure, despite pessimistic opinions regarding the flap survival and low limb salvage rates. It should be considered a useful reconstructive option for serious defects in well-selected cases. © 2005 Wiley-Liss, Inc. Microsurgery 25:107,112, 2005. [source] Acute remote ischemic preconditioning on a rat cremasteric muscle flap modelMICROSURGERY, Issue 6 2002Markus V. Küntscher M.D. A previous study showed, in a rat adipocutaneous flap model, that acute ischemic preconditioning (IP) can be achieved not only by preclamping of the flap pedicle, but also by a brief extremity ischemia prior to flap ischemia. The purpose of this study was to determine whether remote IP is also effective in other tissues such as muscle flaps. Twenty male Wistar rats were divided into three experimental groups. The rat cremaster flap in vivo microscopy model was used for assessment of ischemia/reperfusion injury. In the control group (CG, n = 8), a 2-hr flap ischemia was induced after preparation of the cremaster muscle. In the "classic" IP group (cIP, n = 6), a brief flap ischemia of 10 min was induced by preclamping the pedicle, followed by 30 min of reperfusion. A 10-min ischemia of the contralateral hindlimb was induced in the remote IP group (rIP, n = 6). The limb was then reperfused for 30 min. Flap ischemia and the further experiment were performed as in the CG. In vivo microscopy was performed after 1 hr of flap reperfusion in each animal. A significantly higher red blood cell velocity in the first-order arterioles and capillaries, a higher capillary flow, and a decreased number of leukocytes adhering to the endothelium of the postcapillary venules were observed in both preconditioned groups by comparison to the control group (P < 0.05). The differences within the preconditioned groups were not significant for these parameters. Our data show that ischemic preconditioning and improvement of flap microcirculation can be achieved not only by preclamping of the flap pedicle, but also by induction of an ischemia/reperfusion event in a body area distant from the flap prior to elevation. These findings indicate that remote IP is a systemic phenomenon, leading to an enhancement of flap survival. Our data suggest that remote IP could be performed simultaneously with flap elevation in the clinical setting without prolongation of the operation and without invasive means. © 2002 Wiley-Liss, Inc. MICROSURGERY 22:221,226 2002 [source] Beneficial effect of hyperbaric oxygen on island flaps subjected to secondary venous ischemia,MICROSURGERY, Issue 2 2002Thomas J. Gampper M.D. The potential for hyperbaric oxygen therapy (HBO) to decrease the untoward effects of a secondary ischemic event was studied in the rat superficial epigastric flap model. The secondary venous ischemic flap was created by cross-clamping the vascular pedicles for 2 h. Twenty-four hours later, the flap was reelevated and the venous pedicle was occluded for 5 h. Thirty-two rats were divided into three groups. In experimental group 1, animals received HBO treatment immediately prior to the initial flap elevation and ischemia at 2 atmosphere pressures for 90 min. In experimental group 2, the rats underwent a similar course except for a second 90-min HBO course immediately prior to the secondary venous occlusion. The rats without HBO therapy were used as controls. The results showed that all control flaps were nonviable at 1 week by clinical inspection and fluorescein injection. Complete flap survival occurred in 20% of group 1 flaps and 30.8% of group 2 flaps. Partial flap survival occurred in the rest of the flaps in these two groups, with mean survival areas of 48% and 55%, respectively. In conclusion, HBO treatments significantly increase the survival of flaps subjected to a secondary ischemia, even if administered before the primary ischemia. Administering HBO prior to secondary venous ischemia was marginal, which may be due to the effect of O2 given by HBO not lasting longer than 5 h. © 2002 Wiley-Liss, Inc. MICROSURGERY 22:49,52 2002 [source] Effects of Tisseel and FloSeal on Primary Ischemic Time in a Rat Fasciocutaneous Free Flap Model,THE LARYNGOSCOPE, Issue 2 2004Aaron W. Partsafas BS Abstract 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 × 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. [source] Elective peri-operative intra-aortic balloon counterpulsation during maxillofacial free flap reconstructive surgery in a patient with severe cardiomyopathyANAESTHESIA, Issue 2 2010A. Jennings Summary A key anaesthetic goal in reconstructive free flap surgery is to maintain optimum blood flow to maximise flap survival. We describe the use of intra-aortic balloon counterpulsation in a patient with severe cardiac dysfunction, in whom surgery was initially felt to be contraindicated. [source] Local heat-shock priming-induced improvement in microvascular perfusion in osteomyocutaneous flaps is mediated by heat-shock protein 32BRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 3 2001Dr M. Rücker Background: Stress conditioning is thought to improve microvascular free flap survival but the mechanisms of protection are not clear. The aim of this study was to determine whether local induction of heat-shock protein (HSP) 32 improves microvascular perfusion in transferred osteomyocutaneous flaps. Methods: The hindlimb harvest region of osteomyocutaneous flaps in Wistar rats was subjected to stress conditioning by local heating (30 min, 42·5°C) 24 h before microvascular flap transfer. In a second group of animals, after heat-shock priming, the action of HSP-32 was inhibited by tin protoporphyrin IX. Animals with unconditioned flaps served as controls. After transfer, the microcirculation of the muscle, cutaneous, subcutaneous and periosteal tissue of the flap was analysed quantitatively for 6 h using intravital fluorescence microscopy. Results: Immunohistochemistry revealed that HSP-32 was detectable only after priming and not in unconditioned flaps. Priming did not alter functional capillary density or capillary red blood cell velocity compared with that in unconditioned flaps. However, heat-shock priming induced significant capillary dilatation (P < 0·05) and thus a substantial increase in capillary blood flow volume (P < 0·05) in all tissues of the transferred flaps. Inhibition of HSP-32 by tin protoporphyrin IX completely abolished the priming-induced improvement in capillary perfusion, as indicated by the lack of increased capillary diameters and volumetric blood flow. Conclusion: The present study demonstrated that stress conditioning by local heat-shock priming improves nutritive perfusion in osteomyocutaneous flaps by capillary dilatation, probably mediated through the vasoactive action of HSP-32. © 2001 British Journal of Surgery Society Ltd [source] |