Vascular complications and microvascular free flap salvage: The role of thrombolytic agents

The Use of Fibrinolytic Agents in the Salvage of Free Flaps: A Systematic Review

BACKGROUND

Microvascular thrombosis following free tissue transfer presents a complex challenge for surgeons and carries the potential risk of flap failure. The application of fibrinolytic agents represents a robust therapeutic option. The aim of this systematic review is to provide a comprehensive overview of the clinical use of fibrinolytic drugs in the rescue of compromised free flaps.

METHODS

A systematic literature search for clinical studies detailing the utilization of fibrinolytic agents for salvaging free flaps was conducted using the PubMed and Web of Science databases. The inclusion criteria encompassed English-language publications that specifically addressed the clinical application of fibrinolytic agents for free-flap salvage.

RESULTS

A total of 331 articles were screened after excluding duplicates, with 56 meeting the inclusion criteria. Among these, 21 were clinical trials (evidence level III), and 35 were case studies (evidence level IV/V). In total, 459 flaps underwent treatment with fibrinolytic agents.

CONCLUSION

The application of fibrinolytic agents appears to be a valuable intervention for rescuing compromised free flaps attributable to microvascular compromise. Notably, no prospective randomized trials have been published on this subject, and the evidence within the existing literature is characterized by its limited and heterogeneous nature. Further research is imperative to gather data on the efficacy, dosage, and safety profile of fibrinolytic agents.

An Interdisciplinary, Comprehensive Recovery Pathway Improves Microsurgical Breast Reconstruction Delivery

INTRODUCTION

Free-flap (autologous) breast reconstruction demonstrates superiority over alloplastic approaches but is offered infrequently. Enhanced recovery protocols can address postoperative challenges, but most literature is limited to inpatient interventions and outcomes. This study describes an adoptable, longitudinally comprehensive and multidisciplinary recovery pathway for autologous reconstruction which adds to the current guidelines. The authors aimed to allow perioperative outcomes comparable to alloplastic reconstructions.

METHODS

All autologous Comprehensive Recovery Pathway (CRP) subjects from a single surgeon were retrospectively included. A comparator group of equal size was randomly selected from institutional subpectoral and dual-plane tissue expander patients having Enhanced Recovery After Surgery guideline-directed care. All subjects in both cohorts received preoperative paravertebral regional blocks. Operative detail, inpatient recovery, longitudinal morphine equivalents (MEs) required, and complications were compared.

RESULTS

Each cohort included 71 cases (99 breasts). Despite longer operations, intraoperative MEs were fewer in autologous cases ( P = 0.02). Morphine equivalents during inpatient stay were similar between cohorts, with both being discharged on median day 2. Multivariate regression demonstrated a 0.8-day increased stay for autologous subjects with additional contribution from bilateral cases, body mass index, and age ( P < 0.05). Autologous subjects were regularly discharged postoperative day 1 (17%) and postoperative day 2 (39%), with trend toward earlier discharge ( P < 0.01). Outpatient MEs were significantly fewer in autologous subjects, corresponding to a 30- to 150-mg oxycodone difference ( P < 0.01). Major complication occurred in 12.7% of autologous and 22.5% of alloplastic subjects ( P = 0.11). Flap loss occurred in 1 autologous subject versus 11 alloplastic failures ( P < 0.01).

CONCLUSIONS

This study details partnership between the plastic surgery service, regional and acute pain anesthesia services, and dedicated nursing with longitudinal optimizations allowing perioperative outcomes improved over current literature. Patients in the CRP used fewer opioids from operation through follow-up with comparable length of stay and significantly fewer reconstructive failures than alloplastic subjects. The pathway may be quickly adopted into academic practice patterns and mitigates traditional barriers, allowing extension of autologous reconstruction offerings.

Reoperative Microsurgical Free Flap Surgery: Lessons Learned

ABSTRACT

Microsurgical free flap surgery has revolutionized reconstructive surgery at most academic centers worldwide. However, free flap failures still occur even in the hands of the most experienced microsurgeon. Although we have achieved a great deal of success performing microsurgical free flap reconstruction for various indications, complications from initial free flap surgery that result in reoperation remain a small, but steady percentage. Venous flap congestion is one of the most challenging conditions that result in free flap failure if not resolved promptly. It can be caused by several conditions, and salvage for venous congestion is often difficult and time consuming. Over 20 years, the senior author has encountered 2 unique situations that resulted in venous congestion of the flap requiring reoperative surgery for flap salvage or a second free flap. Several medical conditions can compromise free flap surgery and result in total flap loss. The senior author has also encountered 2 medical conditions resulting in total flap loss. However, both patients received successful second free tissue transfers when combined with unique perioperative management strategies. It is our hope that this review will highlight some unique management strategies for reoperative microsurgical free tissue transfer and serve as "lessons learned" for initial salvage procedures and a second free tissue transfer. We also hope our reoperative approach demonstrated in this review will help the future generation of microsurgeons to avoid such complications altogether so that overall outcome after microsurgical free flap surgery can further be improved.

Continuous local intravenous heparin infusion after re-exploration for venous congestion in free-flap breast reconstruction: A case series

We demonstrated local intravenous heparin infusion to salvage flaps after re-exploration for postoperative venous congestion after free-flap breast reconstruction. All flaps were salvaged using local intravenous heparin infusion without major complications. Local intravenous heparin infusion is an effective and safe procedure.

Effect of Perioperative Antithrombotics on Head and Neck Microvascular Free Flap Survival After Anastomotic Revision

OBJECTIVE

To determine if antithrombotic therapy improves head and neck microvascular free flap survival following anastomotic revision.

STUDY DESIGN

A retrospective review of all patients with microvascular free tissue transfer to the head and neck between August 2013 and July 2021.

SETTING

Otolaryngology-Head and Neck Surgery Departments at University of Alabama at Birmingham, University of Colorado, and University of California Irvine.

METHODS

Perioperative use of anticoagulation, antiplatelets, intraoperative heparin bolus, tissue plasminogen activator (tPA) and vasopressor use, and leech therapy were collected plus microvascular free flap outcomes. The primary endpoint was free flap failure. Analyses of free flaps that underwent anastomotic revision with or without thrombectomy were performed.

RESULTS

A total of 843 microvascular free flaps were included. The overall rate of flap failure was 4.0% (n = 34). The overall rate of pedicle anastomosis revision (artery, vein, or both) was 5.0% (n = 42) with a failure rate of 47.6% (n = 20) after revision. Anastomotic revision significantly increased the risk of flap failure (odds ratio [OR] 52.68, 95% confidence interval [CI] [23.90, 121.1], p < .0001) especially when both the artery and vein were revised (OR 9.425, 95% CI [2.117, 52.33], p = .005). Free flap failure after the anastomotic revision was not affected by postoperative antiplatelet therapy, postoperative prophylactic anticoagulation, intraoperative heparin bolus, tPA, and therapeutic anticoagulation regardless of which vessels were revised and if a thrombus was identified.

CONCLUSION

In cases of microvascular free tissue transfer pedicle anastomotic revision, the use of antithrombotic therapy does not appear to significantly change free flap survival outcomes.

How do i salvage that flap?; An evidence-based primer on salvage techniques for head & neck microvascular free flaps

Interventional strategies for dealing with microvascular free flap failure are varied among institutions and even individual surgeons. This systematic review aims to identify the published methods for salvaging a failing free flap and provide surgeons with a comprehensive toolset for successful intervention. A title and abstract search of the PubMed, Embase, and Web of Science databases was performed. 1694 abstracts were screened by three reviewers according to Prisma guidelines. 62 full text articles meeting inclusion criteria detailed techniques which were separated into the categories of thrombectomy, thrombolysis, leech therapy, vascular fistula, and an "other" category outlining techniques which did not fit into the prior framework. Assessment of the efficacy of individual salvage techniques is limited due to limited empirical data, however, the approach to successful salvage should be based on timely identification of flap compromise, followed by the implementation of one or several of the aforementioned techniques.

Safe and effective thrombolysis in free flap salvage: Intra-arterial urokinase infusion

Despite the high success rate in reconstruction using free tissue transfer, flap failure is often caused by microvascular thrombosis. In a small percentage of cases with complete flap loss, a salvage procedure is performed. In the present study, the effectiveness of intra-arterial urokinase infusion through the free flap tissue was investigated to develop a protocol to prevent thrombotic failure. The retrospective study evaluated the medical records of patients who underwent salvage procedure with intra-arterial urokinase infusion after reconstruction with free flap transfer between January 2013 and July 2019. Thrombolysis with urokinase infusion was administered as salvage treatment for patients who experienced flap compromise more than 24 hours after free flap surgery. Because of an external venous drainage through the resected vein, 100,000 IU of urokinase was infused into the arterial pedicle only into the flap circulation. A total of 16 patients was included in the present study. The mean time to re-exploration was 45.4 hours (range: 24-88 hours), and the mean quantity of infused urokinase was 69,688 IU (range: 30,000-100,000 IU). 5 cases presented with both arterial and venous thrombosis, while 10 cases had only venous thrombosis and 1 case had only arterial thrombosis; in a study of 16 patients undergoing flap surgery, 11 flaps were found to have survived completely, while 2 flaps experienced transient partial necrosis and 3 were lost despite salvage efforts. In other word, 81.3% (13 of 16) of flaps survived. Systemic complications, including gastrointestinal bleeding, hematemesis, and hemorrhagic stroke, were not observed. The free flap can be effectively and safely salvaged without systemic hemorrhagic complications using high-dose intra-arterial urokinase infusion within a short period of time without systemic circulation, even in delayed salvage cases. Urokinase infusion results in successful salvage and low rate of fat necrosis.

Ex Vivo Machine Thrombolysis Reduces Rethrombosis Rates in Salvaged Thrombosed Myocutaneous Flaps in Swine

BACKGROUND

There is a risk for thrombotic complications (2 to 5 percent) associated with microsurgical reconstruction. Current thrombolytic therapy has a salvage rate between 60 and 70 percent, but it is afflicted by bleeding complications (2 to 6 percent). The use of machine perfusion for delivering thrombolytic agents is a new method that could potentially reduce these complications. In this article, the authors compared flap salvage outcomes comparing machine thrombolysis versus a manual flush with tissue plasminogen activator.

METHODS

Sixteen bilateral flaps (12 × 9 cm) were dissected from eight female Dutch Landrace pigs (70 kg). Thrombosis was induced in free rectus abdominis flaps by clamping the pedicle's veins for 2 hours. Flaps were either thrombolysed with 2 mg tissue plasminogen activator (1 mg/ml) during 2 hours of machine perfusion (perfusion group; n = 8) or injected intraarterially (manual group; n = 8) before replantation. Near-infrared fluorescence angiography was used to confirm thrombus formation and to assess tissue perfusion; muscle biopsy specimens were analyzed for ischemia/reperfusion injury directly after thrombolysis and 15 hours after replantation.

RESULTS

A higher incidence of secondary thrombosis was seen in the manual group compared to the perfusion group ( n = 6 versus n = 0, respectively; p < 0.001), resulting in two complete flap failures. Fifteen hours after replantation, mean fluorescence intensities were 13.0 (95 percent CI, 10.1 to 15.8) and 24.6 (95 percent CI, 22.0 to 27.2) in the perfusion and manual group, respectively ( p < 0.001), and mean muscle injury scores were comparable, measuring 7.5 ± 1.5.

CONCLUSION

Two hours of machine thrombolysis of compromised flaps in a porcine model showed higher salvage rates compared to a manual injection with tissue plasminogen activator and reduced the incidence of secondary thrombosis.

CLINICAL RELEVANCE STATEMENT

Using machine perfusion systems for ex vivo thrombolysis provides the benefits of local treatment of a composite tissue without the risk of systemic complications and may improve salvage rates and reduce the incidence of secondary thrombosis.

Anterograde Injection of Alteplase Salvages Deep Inferior Epigastric Perforator Flap in Reconstructive Breast Surgery

The DIEP flap is currently considered the gold standard for autologous reconstructive breast surgery. Postoperative flap failure due to microvascular postanastomotic thrombotic occlusion is a rare but severe complication. Alteplase, a thrombolytic agent typically used in the setting of an ischemic stroke, myocardial infarction, or pulmonary embolism, has also been injected into the microcirculation of flaps as a rescue procedure due to imminent flap loss. The purpose of this article is to provide an overview and detailed guidance for such a thrombolytic procedure due to suspected thrombotic microsurgical failure in free flap surgery. We report the case of a 43-year-old woman who underwent unilateral breast reconstruction with a DIEP flap at our department. Approximately 12 hours postoperatively, an arterial inflow problem was suspected and revision surgery was performed. Peripheral flap perfusion remained absent without an obvious cause and distal thrombosis was assumed to be present. Therefore, alteplase was gradually injected into the arterial pedicle in the anterograde direction just distal to the anastomosis while clamping the artery proximally. About 3 hours after selective flap thrombolysis, microcirculation of the flap was successfully restored without complications. Anterograde injection of alteplase can successfully salvage a free flap. To our knowledge, evidence for optimal dosing and delivery of alteplase for the treatment of thrombosed DIEP flaps has not been published to date. Our approach presents a therapeutic option that both maximizes alteplase concentration in the flap and minimizes the dosage required for flap salvage to significantly reduce systemic adverse effects.

Success and Outcomes Following a Second Salvage Attempt for Free Flap Compromise in Patients Undergoing Head and Neck Reconstruction

Importance

Incidence of perioperative free flap compromise is low, with successful salvage in up to 70%. When the flap is compromised a second time, the value of intervening is unknown.

Objective

To assess the outcomes of a second revascularization attempt for compromised free flaps.

Design, Setting, and Participants

This multicenter retrospective medical record review included patients undergoing head and neck reconstruction with free flaps at 6 US medical centers from January 1, 2000, through December 30, 2020. Patients were 18 years or older with a history of head and neck defects from cancer, osteoradionecrosis, or other wounds. Of 3510 flaps identified, 79 were successfully salvaged once, became compromised a second time, and underwent attempted salvage.

Main Outcome and Measure

Flaps with a history of initial compromise and successful revascularization demonstrating second episodes of compromise followed by second salvage attempts.

Results

A total of 79 patients (mean age, 64 years; 61 [77%] men) were included in the analysis. Of the 79 flaps undergoing second salvage attempts, 24 (30%) survived while 55 (70%) demonstrated necrosis. Arterial or venous thrombectomy was performed in 17 of the 24 (71%) flaps that survived and 23 of the 55 (42%) flaps demonstrating necrosis (odds ratio, 3.38; 95% CI, 1.21-9.47). When venous compromise was encountered, changing the anastomotic vein was associated with decreased survival compared with not changing the vein (29 of 55 [53%] flaps vs 10 of 24 [42%] flaps); vein revision to an alternative branch was completed in 1 of the 24 (4%) flaps that survived and 19 of the 55 (35%) flaps with necrosis (odds ratio, 0.08; 95% CI, 0.00-0.60). Factors that were not associated with flap survival following second salvage attempts included flap type, cause of flap failure, postoperative complications, patient comorbidities, and heparin administration after second salvage.

Conclusions and Relevance

In this cohort study, second salvage was successful in 30% of free flaps. Flaps that underwent arterial or venous thrombectomy demonstrated better survival, while vein revision to neighboring branch veins was associated with worse flap outcomes.

Management of postoperative microvascular compromise and ischemia reperfusion injury in breast reconstruction using autologous tissue transfer: Retrospective review of 2103 flaps

BACKGROUND

Although rates of microvascular thrombosis following free-flap breast reconstruction are low, debate persists about the optimal methods to restore blood flow and prevent ensuing flap shrinkage or fibrosis. Here we evaluate our management of microvascular compromise, including both a review of our approach for restoring blood flow and addressing the ensuing inflammatory changes following ischemia reperfusion.

METHODS

We conducted a retrospective review of autologous free tissue transfer breast reconstructions from 1/2010 to 1/2020. Patients who had flaps requiring take-back for salvage were identified. Management of microvascular compromise and ischemia reperfusion injury were recorded.

RESULTS

Of 2103 flaps were used in the breast reconstructions, 47 flaps required take-back for microvascular compromise (2.2%). Most flaps were either completely salvaged (n = 29, 61.7%) or partially salvaged (n = 5, 10.6%). Thirteen (27.7%) were a total flap loss, for an overall rate of 0.8% (including 3 flaps with no salvage attempt). Management of microvascular compromise most often included revision of the anastomosis (n = 33, 70.2%), thrombectomy (n = 27, 57.4%), tissue plasminogen activator administration (n = 26, 55.3%), and vein grafts (n = 18, 38.3%). Management of ischemia reperfusion included intraoperative steroids (n = 33, 70.2%), postoperative steroids (n = 17, 38.6%), and postoperative therapeutic anticoagulation (n = 27, 61.3%). Of 34 salvaged flaps, 5 (14.7%) had partial flap loss and/or fat necrosis on clinical examination at an average follow-up of 2.7 ± 2.8 years.

CONCLUSIONS

Salvage of microvascular compromise in autologous breast reconstruction should include restoration of blood flow and management of ischemia reperfusion injury. Attention to both is paramount for successful outcomes.

Primary thrombolysis for free flap surgery in head and neck reconstruction: a case report and review

The use of free flaps is an essential and reliable method of reconstruction in complex head and neck defects. Flap failure remains the most feared complication, the most common cause being pedicle thrombosis. Among other measures, thrombolysis is useful when manual thrombectomy has failed to restore flap perfusion, in the setting of late or established thrombosis, or in arterial thrombosis with distal clot propagation. We report a case of pedicle arterial thrombosis with distal clot propagation which occurred during reconstruction of a maxillectomy defect, and was successfully treated with thrombolysis using recombinant tissue plasminogen activator. We also review the literature regarding the use of thrombolysis in free flap surgery, and propose an algorithm for the salvage of free flaps in head and neck reconstruction.

Management of venous flap insufficiency: the role of low molecular weight heparin in salvage

Flap loss resulting from venous insufficiency is a difficult issue, both with pedicled or free flaps. We examined the efficiency of low molecular weight heparin administration in various forms and dressing methods in venous insufficiency. Forty-five Sprague Dawley rats were included and inferior epigastric artery perforated island flaps were obtained from the abdominal skin of the animals. Nine animals were randomly allocated to each of five experimental groups: sham-control (Group 1), venous occlusion only (Group 2), occlusion with systemic enoxaparin (Group 3), occlusion with systemic enoxaparin + local enoxaparin infusion to the punctiform incisions (Group 4), and occlusion with systemic enoxaparin + local enoxaparin infusion to the punctiform incisions and enoxaparin-impregnated sponge dressing (Group 5). Group 5 had higher flap survival rates than the other groups. Groups 3 and 4 had numerically better vitality than the control group, but the difference was not significant. Low molecular weight heparin administration, with or without punctiform incisions, is not efficient in rescuing flaps with venous insufficiency. Specialised dressing methods are necessary to maintain bleeding.

Multidisciplinary Practice Variations of Anti-Thrombotic Strategies for Free Tissue Transfers

Background: Venous thrombosis, the leading cause of free flap failure, may have devastating consequences. Many anti-thrombotic agents and protocols have been described for prophylaxis and treatment of venous thrombosis in free flaps. Methods: National surveys were distributed to microsurgeons (of both Plastics and ENT training) and hematology and thrombosis specialists. Data were collected on routine screening practices, perceived risk factors for flap failure, and pre-, intra-, and post-operative anti-thrombotic strategies. Results: There were 722 surveys distributed with 132 (18%) respondents, consisting of 102 surgeons and 30 hematologists. Sixty-five surgeons and 9 hematologists routinely performed or managed patients with free flaps. The top 3 perceived risk factors for flap failure according to surgeons were medical co-morbidities, past arterial thrombosis, and thrombophilia. Hematologists, however, reported diabetes, smoking, and medical co-morbidities as the most important risk factors. Fifty-four percent of physicians routinely used unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH) as a preoperative agent. Surgeons routinely flushed the flap with heparin (37%), used UFH IV (6%), or both (8%) intra-operatively. Surgeons used a range of post-operative agents such as UFH, LMWH, aspirin, and dextran while hematologists preferred LMWH. There was variation of management strategies if flap thrombosis occurred. Different strategies consisted of changing recipient vessels, UFH IV, flushing the flap, adding post-operative agents, or a combination of strategies. Conclusions: There are diverse practice variations in anti-thrombotic strategies for free tissue transfers and a difference in perceived risk factors for flap failure that may affect patient management.

Flap Venous Congestion and Salvage Techniques: A Systematic Literature Review

Venous congestion is a frequent problem in flap surgery. Other than surgical revision, there are a multitude of procedures in the literature to tackle this problem, but their effectiveness is not clear. Through a systematic review, we aimed to identify and evaluate the different interventions available for managing flap venous congestion.

Methods

The MEDLINE, PubMed central, Embase, and Cochrane databases were searched. The study selection process was adapted from the PRISMA statement. All English and French original articles describing or comparing a method for managing flap venous congestion were included. For each article, a level of evidence was assigned, as defined by the Oxford Centre for Evidence-based Medicine. Lastly, we specifically analyzed the effectiveness of postoperative non-surgical methods. No formal analysis was performed.

Results

Through literature searches carried out in various databases, we identified 224 articles. Finally, 72 articles were included. The majority of these studies had a low-level evidence. A total of 17 different methods (7 pre- and intraoperative, and 10 postoperative) were found. Concerning non-surgical methods, the most represented were leeches, local subcutaneous injection of heparin with scarification, venocutaneous catheterization, negative pressure therapy, and hyperbaric oxygen therapy.

Conclusions

Risks of venous congestion of flaps must always be present in a surgeon's mind, at every stage of flap surgery. Apart from studies on the use of leeches, which have a significant follow-up and large enough patient numbers to support their efficacy, the low-level evidence associated with studies of other methods of venous congestion management does not allow us to draw a scientifically valid conclusion about their effectiveness.

The chicken or the egg? Relationship between venous congestion and hematoma in free flaps

BACKGROUND

Postoperative hematoma and venous congestion after free tissue transfer may occur independently or concurrently. We aimed to explore the association between these two events.

METHODS

All free flap reconstructions for head and neck (HN) and breast from a single institution between 2004 and 2014 were retrospectively reviewed for reoperation for venous congestion and/or hematoma.

RESULTS

There were 2985 free flap cases for HN reconstruction and 2345 cases for breast reconstruction. In HN, 100 patients developed a hematoma (3.4%) and 84 patients developed venous congestion (2.8%). The prevalence of hematoma was 17.8% and 2.9% in the presence and absence of congestion, respectively (p<0.001). Among the 15 patients who had both hematoma and venous congestion were separate events that occurred from 1 to 9 days apart in 8 patients. Hematoma caused the compression of the pedicle vein in 4 patients, while venous congestion possibly caused hematoma in 3 patients. In breast, 56 patients developed a hematoma (2.4%) and 64 patients developed venous congestion (2.7%). The prevalence of hematoma was 12.5% and 2.1% in the presence and absence of congestion, respectively (p<0.001). In the 8 patients who developed both, hematoma and congestion were separate events in 4 patients. Venous congestion caused hematoma in 3 patients, and hematoma caused venous congestion in 1 patient.

CONCLUSIONS

Although postoperative hematoma and venous congestion often present concurrently, most events are not causally associated. When related, however, venous congestion leading to hematoma is more common in breast reconstruction, while hematoma preceding venous congestion is more common in HN reconstruction.

Drug-Loaded Microbubbles Combined with Ultrasound for Thrombolysis and Malignant Tumor Therapy

Cardiac-cerebral thrombosis and malignant tumor endanger the safety of human life seriously. Traditional chemotherapy drugs have side effects which restrict their applications. Drug-loaded microbubbles can be destroyed by ultrasound irradiation at the focus position and be used for thrombolysis and tumor therapy. Compared with traditional drug treatment, the drug-loaded microbubbles can be excited by ultrasound and release drugs to lesion sites, increasing the local drug concentration and the exposure dose to nonfocal regions, thus reducing the cytotoxicity and side effects of drugs. This article reviews the applications of drug-loaded microbubbles combined with ultrasound for thrombolysis and tumor therapy. We focus on highlighting the advantages of using this new technique for disease treatment and concluding with recommendations for future efforts on the applications of this technology.

Applications of rib sparing technique in internal mammary vessels exposure of abdominal free flap breast reconstructions: a 12-year single-center experience of 215 cases

Background

Internal mammary vessels (IMVs) are widely used recipient vessels in abdominal free flap breast reconstructions. Rib sparing technique is an alternative method with less damage in IMVs exposure. This study aims to investigate the factors influencing the selection of IMVs, as well as analyze the applicability and related factors of rib sparing technique in abdominal breast reconstruction.

Methods

Medical records of 215 patients who underwent abdominal free flap reconstruction from November 2006 to December 2017 in Fudan University Shanghai Cancer Center (FUSCC) were analyzed. Intercostal space (ICS) was measured from preoperative chest computed tomography scan. Factors influencing the choice of recipient vessels and rib sparing were analyzed. Surgery time, hospitalization and complications were assessed.

Results

Among all 218 flaps, 172 flaps used IMVs as the recipient vessels while 46 used other vessels. patients with immediate reconstruction (P=0.005) and axillary lymph nodes dissection (ALND) (P<0.001) were less likely to use IMVs. Patients' body mass index (BMI) and radiotherapy history showed no statistically significant differences between the two groups (P=0.338 and 0.811). In IMVs group, 62% cases used rib sparing technique. Compared with rib resection group, patients with rib sparing were taller (P=0.047) and with a wider ICS (2.65±0.54 vs. 2.25±0.38 cm, P<0.001). Rib sparing group had a shorter surgery and postoperative hospitalization time, as well as a lower complication rate, but the differences were not statistically significant (P=0.120, 0.450 and 0.612).

Conclusions

IMVs were used more frequently as the recipient vessels in abdominal free flap breast reconstructions, especially when axillary operation was not performed at the same time. Rib sparing technique had the potential to decrease surgery time, hospitalization days and complications rate. It could be applied in most of the patients with IMVs exposure, particularly in taller patients and patients with a wider ICS. Preoperative chest computed tomography scan can be used to assess the ICS width to provide operational suggestions.

Microcirculatory Free Flap Failure With Patent Anastomosis Salvaged by In Situ Thrombolysis in Vulnerable Phase Burn

Free flap reconstruction in acute burns has high failure rates, relating mainly to a systemic inflammatory state. The "vulnerable phase" can last for 6 weeks after burn and can cause thrombosis of the flap microcirculation with patent arterial and venous anastomoses. Revision surgery alone may be unsuccessful, but thrombolysis can lead to flap salvage. We describe a case of successful flap salvage with thrombolysis after unsuccessful revision surgery by permeable arterial and venous anastomoses in a patient in the acute burn phase suffering from microcirculatory thrombosis. Thrombolysis in these cases has not been described to date, but it could contribute to salvaging flaps by radiological intervention alone. A 23-year-old man was admitted with a 38% TBSA burn, including loss of all eyelid skin. The right eye was reconstructed in a satisfactory manner, but the left eye required urgent corneal coverage on day 32 with a dorsalis pedis fasciocutaneous free flap. The flap was hypo-perfused postoperatively, but anastomoses were found to be permeable on exploration. Angiography performed postoperatively after revision confirmed anastomotic patency, but failed to demonstrate small vessel beds within the flap. Thus, r-tPa was given at the anastomosis site and immediately the flap recovered completely. However, a total of 10 packed red blood cell transfusions were needed over the next 9 days. Thrombolysis in the context of free flap microvascular compromise may improve the overall success rates, especially in acute-phase burn patients where this etiology may be found, due to a vulnerable inflammatory period.

The lumbar artery perforator flap: clinical review and guidance on image reporting

The lumbar artery perforator (LAP) flap is a relatively new procedure that can be utilized to manage lumbosacral defects in addition to reconstructing distal body parts as well, such as breast reconstruction. This fasciocutaneous flap is designed based on the LAPs small arteries that emerge from the lumbar arteries then move superficially piercing overlying tissues to perforate the lumbar fascia and supply the skin and subcutaneous tissue; However, anatomical and clinical studies regarding the LAP flap and its perforators are sparse in the literature, and the results are even contradicting. This article will discuss the LAP flap, the anatomy of its perforators, and the clinical aspects about its usage. In addition, we explore its preoperative imaging evaluation, and deliver a guide on image reporting and radiological data that will benefit the surgeon most during the procedure.

Pharmacological thrombolysis: the last choice for salvaging free flaps

Microvascular free flap transfer has become a prevailing surgery with a failure rate of <5%. However, pedicle thrombosis occurs more frequently than indicated by the failure rate. This difference is due to the successful salvage of failing flaps. During exploration, thrombi are often encountered at anastomotic sites, whereas these causes could not explain vascular compromise in other patients. Thus, we hypothesized that thrombogenic processes might occur at remote sites, specifically within microvessels of the transferred flap. This study retrospectively evaluated 323 patients who underwent microvascular free flap transfer between March 2012 and October 2016 at Korea University Guro Hospital. All patients requiring emergency exploration within 7 days after surgery were retrospectively reviewed. Of patients, 15 required explorative surgery for suspected circulatory compromise. Eight were diagnosed with thrombosis at the perianastomotic site and salvaged in accordance with our protocol. There was no detectable thrombosis at the anastomotic site in seven patients, including one patient in whom thrombosis resolved with topical papaverine application and heparinization. The remaining six patients were diagnosed with intra-flap microthrombosis without discernable thrombosis at the anastomotic site. All patients were treated following our urokinase administration protocol and salvaged without complications. Possible external causes should first be evaluated when salvaging free flaps; in the absence of such evidence, urokinase administration may be utilized as a last resort. This study is the first report describing the effectiveness of pharmacological thrombolysis in resolving intra-flap microthrombosis. Furthermore, a safe and efficient urokinase administration protocol is suggested for perianastomotic thrombosis and intra-flap microthrombosis.

Direct thrombectomy as a salvage technique in free flap breast reconstruction

BACKGROUND

Breast reconstruction with microvascular free tissue transfer has become a widely used method. Despite a high rate of success, a compromised flap necessitating re-exploration can occur. Here, we introduce direct thrombectomy as a flap salvage technique, and compared the results with conventional thrombectomy.

METHODS

A total of 488 patients who underwent breast reconstruction using a free transverse rectus abdominis myocutaneous flap between March 2009 and February 2014 were retrospectively analyzed. Flap salvage was conducted by either conventional thrombectomy using a Fogarty catheter, or direct thrombectomy via either a side branch or additional incisions at the stump of the main pedicle at the distal end of the thrombus.

RESULTS

Flap compromise necessitating re-exploration due to extensive pedicle thrombosis was identified in 30 patients (6.1%). Direct thrombectomy was used in 9 patients, and conventional thrombectomy in 21 patients. Direct thrombectomy had a significantly higher success rate of flap salvage than conventional thrombectomy (88.9% vs. 47.6%; P = .049).

CONCLUSIONS

In the event of vascular thrombosis after free flap breast reconstruction, direct thrombectomy at the proximal pedicle stump beside the anastomosis opening appears to be an effective and reliable option that minimizes vessel trauma related to conventional catheter use. © 2016 Wiley Periodicals, Inc. Microsurgery 37:402-405, 2017.

Identification of perioperative risk factor by laser-doppler spectroscopy after free flap perfusion in the head and neck: a prospective clinical study

The aim of this study was to evaluate perioperative flap perfusion using noninvasive monitoring with a laser-Doppler flowmetry and spectrophotometry unit (O2C) and identify whether perioperative blood flow, velocity, hemoglobin level (Hb), and oxygen saturation (SO2 ) measured could be used as indicators of free flap success. Measurements of blood flow, velocity, Hb, and SO2 were performed in 196 microvascular flaps, which had been transferred into the oral cavity to reconstruct ablative defects after surgery for oral cancer. The values were calculated superficially on the skin surface and at a depth of 8 mm. The results showed that perioperative absolute values measured were not associated with an increased rate of microvascular revisions or free flap failure. Independent predictors of microvascular revisions at the first postoperative day were the development of a falling trend in superficial and deep blood flow, and velocity in comparison with baseline values of variables measured. On day 2, all superficial and deep values of Hb, flow, and velocity were independent prognostic factors (P < 0.01), demonstrated as a downward trend were associated with a need for revision. The superficial and deep values of SO2 (P = 0.59 and 0.43, respectively) were not associated with ultimate free flap failure. This is the first clinical study to demonstrate that during early free flap integration to the recipient site different parameters of perfusion and oxygenation play an important role at different points of time. Within the first two postoperative days, changes in these parameters can help influence the decision to revise microvascular anastomoses.

[Interventional angioradiology as a solution for microsurgical flap failure]

The microsurgical failure rate is almost constant for several decades. We present two case reports describing a novel method of free flap salvage using angioradiological techniques. Our first case shows the potential utility of in situ thrombolysis, our second case describes the first use of stents within a microsurgical anastomosis. In boths cases, the flap would have been lost immediately, because flap revisions failed. Thus, before abandoning on a flap, one could perform a simple angiography to evaluate further angioradiological salvage possibilities and hereby contribute to improve long term microsurgical failure rate.

Objective qualitative and quantitative assessment of blood flow with near-infrared angiography in microvascular anastomoses in the rat model

Intraoperative near-infrared indocyanine-green (ICG) angiography enables the visualization of microvascular perfusion and may help in the early detection of complications. The purpose of the present study was to examine whether the effect of microvascular stenoses can be quantitatively assessed by analysis of ICG-angiography in a microvascular model. Graded stenoses and total vessel occlusion of the carotid, aorta, and femoral arteries were created in 25 Wistar rats. Stenoses were graded to reduce arterial flow by 25%, 50%, 75%, and 100% of baseline flow as measured by transit-time flowmeter analyzing the emission signal of the ICG detected and investigated by the mathematical software tool (FLOW 800). ICG angiography was performed to assess vessel perfusion and flow curves were analyzed and correlated with the stenosis rate. A total of 576 investigations were performed. The area under the curve (P < 0.001), first and second maximum (P < 0.001), and the maximum slope to the first maximum (P < 0.001) were found to be of high prognostic value in evaluating the different flow patterns. Differences were displayed in comparisons by the maximum intensity of the ICG-concentrations. The maximum slope to the second maximum was found to be predictive in selected vessel types, and specific changes of the flow curve were found to indicate compromised vascular flow. The FLOW 800 tool applied for ICG angiography has shown to be a quick and reliable method for assessing blood flow in vessels in this study. The dynamic assessment of the ICG signal allows reliable identification of microanastomotic complications with the described parameters.