Risk of Free Flap Failure in Head and Neck Reconstruction: Analysis of 21,548 Cases From A Nationwide Database

The Value of the Nutritional Indicators in Predicting Free Flap Failure From a Multicentre Database

OBJECTIVE

Nutritional and inflammatory statuses have been associated with complications in microvascular-free flaps during head and neck surgeries. This study aimed to evaluate the potential of nutritional indicators in predicting postoperative free flap complications.

STUDY DESIGN

We conducted a 20-year retrospective, case-control study within a defined cohort.

SETTING

The study involved head and neck cancer patients from the Chang Gung Research Database who underwent simultaneous tumor ablation and free flap wound reconstruction between January 1, 2001, and December 31, 2019.

METHODS

We employed logistic regression and stratified analysis to assess the risk of free flap complications and the subsequent need for flap revision or redo in relation to nutritional indicators and other clinical variables.

RESULTS

Of the 8066 patients analyzed, 687 (8.5%) experienced free flap complications. Among these, 197 (2.4%) had free flap failures necessitating a redo of either a free flap or a pedicled flap. Beyond comorbidities such as chronic obstructive pulmonary disease, end-stage renal disease, and a history of prior radiotherapy, every 10-unit decrease in the preoperative prognostic nutritional index (PNI) was consistently associated with an increased risk of both free flap complications and failure. The covariate-adjusted odds ratios were 1.90 (95% confidence interval [CI]: 1.42-2.54) and 1.89 (95% CI: 1.13-3.17), respectively.

CONCLUSION

A lower preoperative PNI suggests a higher likelihood of microvascular free flap complications in head and neck surgeries. Further randomized controlled trial designs are required to establish causality.

Catastrophic complications following microvascular free tissue transfer: A 10-year review of NSQIP data

INTRODUCTION

There is an absence of literature regarding the risks of catastrophic medical outcomes (CMOs) such as stroke, cardiac arrest, and pulmonary embolism in microvascular free tissue transfer. This study aims to determine the CMO and mortality rates, as well as risk factors, associated with microvascular reconstruction of the head and neck, extremity, and breast.

METHODS

This study uses data from the American College of Surgeons National Surgical Quality Improvement Program. Cases of microvascular free tissue transfer from 2012 to 2021 were analyzed to assess the 30-day rates of CMOs, including death, as well as associated risk factors.

RESULTS

Of the 22,839 included patients, 785 (3.44%) experienced 1043 CMOs, including 99 (0.43%) deaths. Pulmonary complications of prolonged respiratory failure and pulmonary embolism were the most common. Independent risk factors included age, male sex, underweight status, longer operation times, American Society of Anesthesiologists (ASA) class of III or above, wound classification other than clean, and underlying conditions such as diabetes, hypertension, chronic obstructive pulmonary disorder, dyspnea, metastatic cancer, and ventilator dependence. CMOs were associated with an average 10-day delay in hospital discharge. Multivariate regression analysis revealed that head and neck reconstructions were associated with increased risk of CMO (OR 4.96; p < 0.0001).

CONCLUSION

This is the largest study to examine CMOs following microvascular free tissue transfer. Compared to previous literature spanning the period between 2006 and 2011, we observed a decreased rate of CMOs but a slight increase in 30-day mortality. Our data provide updated and comprehensive criteria for risk stratification and patient counseling. The modifiable risk factors reported in our study should be considered in elective, non-urgent cases of microvascular reconstruction.

The risk of free flap revision and subsequent medical costs in patients with hypopharyngeal cancer

BACKGROUND

Few studies have examined the preoperative risks and healthcare costs related to free flap revision in hypopharyngeal cancer (HPC) patients.

METHODS

A 20-year retrospective case-control study was conducted using the Chang Gung Research Database, focusing on HPC patients who underwent tumor excision and free flap reconstruction from January 1, 2001, to December 31, 2019. The impacts of clinical variables on the need for re-exploration due to free flap complications were assessed using logistic regression. The direct and indirect effects of these complications on medical costs were evaluated by causal mediation analysis.

RESULTS

Among 348 patients studied, 43 (12.4%) developed complications requiring re-exploration. Lower preoperative albumin levels significantly increased the risk of complications (OR 2.45, 95% CI 1.12-5.35), especially in older and previously irradiated patients. Causal mediation analysis revealed that these complications explained 11.4% of the effect on increased hospitalization costs, after controlling for confounders.

CONCLUSIONS

Lower preoperative albumin levels in HPC patients are associated with a higher risk of microvascular free flap complications and elevated healthcare costs, underscoring the need for enhanced nutritional support before surgery in this population.

LEVEL OF EVIDENCE: 3

Does the Anastomosis Recipient Vessel Have an Influence on Free Flap Perfusion in Microvascular Head and Neck Reconstruction-A Retrospective Analysis of 338 Cases with Comparison of Flap Perfusion between Different Arterial and Venous Recipient Vessels in Radial Free Forearm Flaps, Anterolateral Thigh Flaps, and Fibula Free Flaps

Background: Flap perfusion is a prerequisite for microvascular free flap survival and a parameter routinely used for flap monitoring. The aim of this study was to investigate the influence of the anastomosis recipient vessel on flap perfusion. Methods: Flap perfusion was retrospectively analyzed in 338 patients who underwent head and neck reconstruction with microvascular free flaps between 2011 and 2020. The Oxygen-to-see tissue oxygen analysis system measurements for intraoperative and postoperative flap blood flow, hemoglobin concentration, and hemoglobin oxygen saturation at 8 and 2 mm tissue depths were compared between arterial anastomosis recipient vessels (external carotid artery [ECA], facial artery [FAA], lingual artery [LIA], and superior thyroid artery [STA]) and venous anastomosis recipient vessels (internal jugular vein [IJV], combination of IJV and IJV branches, IJV branches, and external jugular vein). Results: The postoperative hemoglobin concentration at 2 mm tissue depth differed significantly between arterial anastomosis recipient vessels (ECA, 41.0 arbitrary units [AU]; FAA, 59.0 AU; LIA, 51.5 AU; STA, 59.0 AU; p = 0.029). This difference did not persist in the multivariable testing (p = 0.342). No other differences in flap blood flow, hemoglobin concentration, or hemoglobin oxygen saturation were observed between the arterial and venous anastomosis recipient vessels (p > 0.05 for all). Conclusions: The arterial and venous recipient vessels used for anastomosis did not influence microvascular free flap perfusion. This underlines the capability of the studied recipient vessels to adequately perfuse free flaps, may explain the observed indifferent flap survival rates between commonly used anastomosis recipient vessels, and implies that the recipient vessel is not a confounding variable for flap monitoring with the Oxygen-to-see tissue oxygen analysis system. Further prospective studies are needed to confirm the findings.

A Survey of Microvascular Technique Preferences Among American Head Neck Society Members

OBJECTIVE

To identify practices in microvascular techniques in routine and challenging scenarios.

STUDY DESIGN

Cross-sectional study.

METHODS

A national survey addressing practices related to microvascular free flap reconstruction was distributed to AHNS members between October and November 2021.

RESULTS

The respondents encompassed 95 microvascular surgeons. Median years of practice was 6 (interquartile range, 2-13) and median flaps per year was 35 (22-50). Common practices in arterial anastomosis included limited cleaning of artery (84.2%), use of a double approximating clamp (64.2%), and use of interrupted suture (88.4%). Common practices in venous anastomosis included limited cleaning (89.5%), downsizing the coupler (53.7%), and coupling to two independent venous systems (47.4%). In arterial anastomosis, respondents felt that kinking (50.5%) and tension (24.2%) were the riskiest challenges. Kinking was handled by loose sutures or native tissue/dissolvable biomaterial to orient pedicle. Excess tension was handled by additional dissection. With regards to associated practices, most surgeons perform anastomosis after partial inset (52.6%), give aspirin immediately postoperatively (66.3%), reserve transfusion for hemodynamic instability (69.5%), and utilize intraoperative pressors when needed (72.6%). More senior surgeons reported placing more suture to address leaks (p = 0.004) and perform end to side anastomosis on larger vein in case of venous mismatch (p = 0.012). In cases of tension, higher volume surgeons perform more extensive dissection (p = 0.035) and end to side coupling (p = 0.029).

CONCLUSIONS

This survey of AHNS members indicates patterns of microvascular techniques in routine and challenging scenarios. There exists a variation in approaches amongst surgeons based on volume and practice length.

LEVEL OF EVIDENCE

5 Laryngoscope, 134:1265-1277, 2024.

Introduction and preliminary application report for a novel 3D printed perforator navigator for fibular flap surgery

The aim of this study was to introduce and report on a 3D-printed perforator navigator and its clinical application. Integrated imaging and 3D printing techniques were employed for the design and manufacture of a perforator navigator. Key techniques included establishing a digital image coordinate system, localizing perforator fascia piercing points, creating a reference plane for the perforator course, and projecting the perforator course onto the body surface. All cases of maxillofacial defect repaired with free fibular myocutaneous flaps, from January 2019 to January 2022, were reinvestigated. Patients treated using traditional perforator localization methods were assigned into group Ⅰ, while those who had a navigator used during treatment were allocated to group Ⅱ. Outcome measurements included perforator positioning accuracy, perforator preparation time (PT), and flap growth score. Capillary refilling time and degree of flap swelling were recorded on the 1st, 3rd, and 7th days after surgery. On the 10th day after surgery, the flap survival situation was graded. In total, 25 patients were included in the study. Perforator preparation time for group Ⅱ was significantly less (p ＝ 0.04) than for group Ⅰ (1038.6 ± 195.4 s versus 1271.4 ± 295.1 s. In group Ⅱ, the mean positioning deviation for the perforator navigator was 2.12 cm less than that for the high-frequency color Doppler (p ＝ 0.001). Group Ⅱ also had a higher score than group Ⅰ for overall flap growth evaluation (nonparametric rank sum test, p ＝ 0.04). Within the scale of the study, it seems that perforator localization and navigation using a 3D-printed navigator is technically feasible, and helps to improve the clinical outcome of free fibular flaps. The perforator navigator will play a useful role in displaying the perforator course, improving the accuracy of perforator localization, reducing surgical injury, and ultimately enhancing flap success rate.

Free Flap Outcomes for Head and Neck Surgery in Patients with COVID-19

INTRODUCTION

Coronavirus disease 2019 (COVID-19) affects the vascular system, subjecting patients to a hypercoagulable state. This is of particular concern for the success of microvascular free flap reconstruction. This study aims to report head and neck free flap complications in patients with COVID-19 during the perioperative period. We believe these patients are more likely to experience flap complications given the hypercoagulable state.

METHODS

This is a multi-institutional retrospective case series of patients infected with COVID-19 during the perioperative period for head and neck free flap reconstruction from March 2020 to January 2022.

RESULTS

Data was collected on 40 patients from 14 institutions. Twenty-one patients (52.5%) had a positive COVID-19 test within 10 days before surgery and 7 days after surgery. The remaining patients had a positive test earlier than 10 days before surgery. A positive test caused a delay in surgery for 16 patients (40.0%) with an average delay of 44.7 days (9-198 days). Two free flap complications (5.0%) occurred with no free flap deaths. Four patients (10.0%) had surgical complications and 10 patients had medical complications (25.0%). Five patients (12.5%) suffered from postoperative COVID-19 pneumonia. Three deaths were COVID-19-related and one from cancer recurrence during the study period.

CONCLUSION

Despite the heightened risk of coagulopathy in COVID-19 patients, head and neck free flap reconstructions in patients with COVID-19 are not at higher risk for free flap complications. However, these patients are at increased risk of medical complications.

LEVEL OF EVIDENCE

4 Laryngoscope, 2023.

Intraoperative Enteral Nutrition Feeding in Free-Flap Healing after Reconstruction Surgery for Head and Neck Cancers

OBJECTIVE

To investigate the beneficial outcomes of intraoperative enteral feeding in free-flap regeneration after extended head and neck cancer resection and flap reconstruction surgery.

STUDY DESIGN

A pilot randomized, double-blind, placebo-controlled clinical trial.

SETTING

Single tertiary care center.

METHODS

Patients with advanced head and neck cancers requiring radical tumor resections and free-flap reconstruction were randomly assigned to receive intraoperative enteral nutrition feeding (100 kcal/100 mL at 10-20 mL/h) via a nasogastric tube during free-flap reconstruction (n = 28) or continue fasting (n = 28). The primary outcome was impaired free-flap regeneration that required surgical reintervention within 90 days after the operation. Participants were enrolled between April 2020 and January 2022; the 90-day follow-up ended in April 2022.

RESULTS

The incidence of total or partial flap failure was similar between the 2 groups (14.2% or n = 4 in each group), but the rate of wound dehiscence or edge necrosis was significantly reduced in the feeding group (n = 6 vs 0 for fasting vs feeding; absolute risk reduction, 25.0% [95% confidence interval, 6.9-43.0]%; p = 0.022). Hospital stay length was shorter (p = 0.042) and hand grip strength was better preserved (p = 0.025) in the feeding group. Plasma concentrations of interleukin (IL)-6 and IL-8 after the operation increased significantly more in the fasting group. Perioperative adverse events did not differ between the 2 groups.

CONCLUSION

Perioperative enteral feeding is a simple, safe, and effective approach to improve perioperative systemic catabolism and proinflammatory reactions, thereby enhancing early wound regeneration after major operations.

Attached compared with unattached surface probes for monitoring flap perfusion in microvascular head and neck reconstruction: a feasibility study

Unattached surface probes are commonly used with the O2C analysis system (LEA Medizintechnik, Germany) to monitor microvascular free flap perfusion. This study compared attached and unattached surface probes for extraoral free flaps. The study included 34 patients who underwent extraoral microvascular head and neck reconstruction between 2020 and 2022. Flap perfusion was monitored postoperatively using the O2C analysis system at 0, 12, 24, 36, and 48 h, with an attached surface probe at 3 mm tissue depth and an unattached surface probe at 2 mm and 8 mm tissue depths. Clinical complications, technical errors, and perfusion measurement values were compared. No clinical complications (attachment suture infections) or technical errors (probe detachment) occurred. Flap blood flow values of the probes were partially different (3 mm vs. 2 and 8 mm: p < 0.001; p = 0.308) and moderately correlated (3 mm with 2 and 8 mm: r = 0.670, p < 0.001; r = 0.638, p < 0.001). Hemoglobin concentration and oxygen saturation values were generally different (3 mm vs. 2 and 8 mm: all p < 0.001) and variably correlated (3 mm with 2 and 8 mm: r = 0.756, r = 0.645; r = 0.633, r = 0.307; all p < 0.001). Both probes are comparable in terms of technical feasibility and patient safety, with flap perfusion values dependent on tissue measurement depth.

Flap perfusion monitoring with an attached surface probe in microvascular reconstruction of the oral cavity

OBJECTIVES

Postoperative flap monitoring is essential in oral microvascular reconstruction for timely detection of vascular compromise. This study investigated the use of attached surface probes for the oxygen-2-see (O2C) analysis system (LEA Medizintechnik, Germany) for intraoral flap perfusion monitoring.

MATERIALS AND METHODS

The study included 30 patients who underwent oral reconstruction with a microvascular radial-free forearm flap (RFFF) or anterolateral thigh flap (ALTF) between 2020 and 2022. Flap perfusion was measured with attached (3-mm measurement depth) and unattached surface probes (2- and 8-mm measurement depths) for the O2C analysis system at 0, 12, 24, 36, and 48 h postoperatively. Flap perfusion monitoring with attached surface probes was evaluated for cut-off values for flap blood flow, hemoglobin concentration, and hemoglobin oxygen saturation indicative of vascular compromise and for accuracy and concordance with unattached surface probes.

RESULTS

Three RFFFs were successfully revised, and one ALTF was unsuccessfully revised. The cut-off values indicative of vascular compromise for flap perfusion monitoring with attached surface probes were for RFFF and ALTF: blood flow < 60 arbitrary units (AU) and < 40AU, hemoglobin concentration > 100AU and > 80AU (both > 10% increase), and hemoglobin oxygen saturation < 40% and < 30%. Flap perfusion monitoring with attached surface probes yielded a 97.1% accuracy and a Cohen's kappa of 0.653 (p < 0.001).

CONCLUSIONS

Flap perfusion monitoring with attached surface probes for the O2C analysis system detected vascular compromise accurately and concordantly with unattached surface probes.

CLINICAL RELEVANCE

Attached surface probes for the O2C analysis system are a feasible option for intraoral flap perfusion monitoring.

Clinical analysis of factors affecting the failure of free flaps used in head and neck reconstruction

BACKGROUND

Free tissue transfer is the preferred method of reconstructing head and neck defects, with a success rate of approximately 95%. Although flap failure is uncommon, it has a major impact on patient morbidity and diminishes quality of life, making it is important to investigate the causes of flap failure.

METHODS

This retrospective chart review analyzed patients who underwent free tissue transfer during head and neck reconstruction at a single institution between 2016 and 2021.

RESULTS

During the study period, 58 patients underwent 60 free flap procedures. Revision surgery was needed in 14 patients. Subsequent free flap surgery was performed in one patient, and three free flaps (5%) could not be salvaged. Cardiovascular disease was significantly associated with flap failure, and venous congestion (thrombosis) was the most common reason for revision surgery.

CONCLUSION

Cardiovascular disease clearly emerged as a factor related to the failure of free flap surgery, and this issue warrants particular attention in patients for whom free tissue transfer is planned.

Post-reconstruction Free Flap Complications After Oral Cancer Ablation

Introduction

Microvascular free flap transfer is considered a standard reconstruction after the ablation of oral cancer. Although the success rate is high, flap complications occasionally occur. This study investigated the reasons for and local factors involved in complications of free flap transfer and explored how to salvage the flaps.

Patients and Methods

The cases of 53 patients who underwent a free flap transfer [radial forearm flaps (n = 36), abdominis musculocutaneous flaps (n = 6), scapular osteocutaneous flaps (n = 10), and fibular osteocutaneous flap (n = 1)] were analyzed: flap complications were observed in five of the cases.

Results

In the all five cases, a salvage operation was performed under general anesthesia. The flap complications occurred within 33 h after anastomosis. In the salvage operation, thrombotic occlusion in veins of flap feeders was observed in three of the five cases. The possible reasons for flap complications were a twisting of the anastomosed vein where two veins were united, pressure to the feeder due to subcutaneous hematoma, and edema of adjacent tissue and/or drain tube; the reason was not clear in one case. The flaps were successfully salvaged in four cases by thrombectomy in veins, release of pressure at the veins, and/or interposition of the vein graft.

Conclusion

Surgeons should pay close attention to the pressure and/or twisting in the feeder as well as the hemostasis in the surgical field, and a salvage operation should be carried out immediately when a flap complication is identified.

Microvascular reconstructions in oral and maxillofacial surgery - Results of a survey among oral and maxillofacial surgeons in Germany, Austria, and Switzerland

This study aimed to evaluate the use of microvascular free flaps (MFF) in oral and maxillofacial surgery (OMFS) in Germany, Austria, and Switzerland. A dynamic online questionnaire, using 42-46 questions, was sent to OMF surgeons based in hospitals in Germany, Austria, and Switzerland. The questionnaire was evaluated internally and externally. Aside from general information, data were collected on organizational aspects, approaches, MFF types and frequency, presurgical planning, intraoperative procedures, perioperative medications, flap monitoring, and patient management. Participants mostly performed 30-40 MFF each year (11/53). Most stated that the COVID-19 pandemic did influence MFF frequency (25/53) to varying extents. Radial forearm flap was most frequently used (37/53), followed by ALT (5/53), and fibula flap (5/53). Primary reconstruction was performed by most participants (35/48). Irradiated bony transplants were mostly used for implant placement after 12 months (23/48). Most participants (38/48) used reconstruction plates, followed by miniplates (36/48), PSI reconstruction (31/48), and PSI miniplates (10/48). Regarding the postoperative use of anticoagulants, low-molecular-weight (37/48) and unfractioned heparins (15/48) were widely used, most often for 3-7 days (26/48). Clinical evaluation was mostly preferred for flap monitoring (47/48), usually every 2 h (34/48), for at least 48 h (19/48). Strong heterogeneity in MFF reconstructions in OMFS was found, especially regarding the timepoints of reconstruction, types of osteosynthesis, and postoperative MFF management. These findings provide the chance to further compare the different treatment algorithms regarding relevant MFF aspects, such as postoperative management. This could create evidence-based treatment algorithms that will further improve the clinical outcomes in MFF reconstructions.

Preoperative anemia: Predictor of free flap reconstruction complications in head and neck cancer

Free flap reconstruction has been the mainstay among reconstruction surgeries for head and neck cancer. Intraoperative and postoperative hemoglobin (Hb) levels were both possible risk factors of flap failure and had been discussed widely. However, few investigations of preoperative Hb were seen in the previous study with its effect to flap condition remain uncertain and no conclusions in the literature. Patients who underwent free flap reconstruction after head and neck surgery in our institution between May 2014 and May 2019 were enrolled. The postoperative flap condition was observed carefully, and re-exploration was performed if necessary. We then retrospectively collected patient data with several intraoperative and postoperative indices. A total of 598 patients were enrolled in our study. The total major flap complication rate was 10.6%, with an overall success rate of 89.4%. They were predominantly male (95%), and most of them underwent free flap reconstruction for the first time (91%). A total of 81 (13%) patients received radiotherapy before reconstruction. Among all factors, the preoperative Hb level and free flap type showed significance in univariate and multivariate analyses. A previous history of radiotherapy, body mass index, nutrition status, or poorly controlled diabetes mellitus showed no significant results in either univariate or multivariate analysis. Our study showed that a lower preoperative Hb level affects free flap survival. Meanwhile, preoperative radiotherapy history has no significant influence in either univariate or multivariate analysis.

Perioperative Outcomes in Patients Who Underwent Fibula, Osteocutaneous Radial Forearm, and Scapula Free Flaps: A Multicenter Study

Importance

Studies comparing perioperative outcomes of fibula free flaps (FFFs), osteocutaneous radial forearm free flaps (OCRFFFs), and scapula free flaps (SFFs) have been limited by insufficient sample size.

Objective

To compare the perioperative outcomes of patients who underwent FFFs, OCRFFFs, and SFFs.

Design, Setting, and Participants

This cohort study assessed the outcomes of 1022 patients who underwent FFFs, OCRFFFs, or SFFs for head and neck reconstruction performed at 1 of 6 academic medical centers between January 2005 and December 2019. Data were analyzed from September 17, 2021, to June 9, 2022.

Main Outcomes and Measures

Patients were stratified based on the flap performed. Evaluated perioperative outcomes included complications (overall acute wound complications, acute surgical site infection [SSI], fistula, hematoma, and flap failure), 30-day readmissions, operative time, and prolonged hospital length of stay (75th percentile, >13 days). Patients were excluded if data on flap type or clinical demographic characteristics were missing. Associations between flap type and perioperative outcomes were analyzed using logistic regression, after controlling for other clinically relevant variables. Adjusted odds ratios (aORs) with 95% CIs were generated.

Results

Perioperative outcomes of 1022 patients (mean [SD] age, 60.7 [14.5] years; 676 [66.1%] men) who underwent major osseous head and neck reconstruction were analyzed; 510 FFFs (49.9%), 376 OCRFFFs (36.8%), and 136 SFFs (13.3%) were performed. Median (IQR) operative time differed among flap types (OCRFFF, 527 [467-591] minutes; FFF, 592 [507-714] minutes; SFF, 691 [610-816] minutes). When controlling for SSI, FFFs (aOR, 2.47; 95% CI, 1.36-4.51) and SFFs (aOR, 2.95; 95% CI, 1.37-6.34) were associated with a higher risk of flap loss than OCRFFFs. Compared with OCRFFFs, FFFs (aOR, 1.77; 95% CI, 1.07-2.91) were associated with a greater risk of fistula after controlling for the number of bone segments and SSI. Both FFFs (aOR, 1.77; 95% CI, 1.27-2.46) and SFFs (aOR, 1.68; 95% CI, 1.05-2.69) were associated with an increased risk of 30-day readmission compared with OCRFFFs after controlling for Charlson-Deyo comorbidity score and acute wound complications. Compared with OCRFFFs, FFFs (aOR, 1.78; 95% CI, 1.25-2.54) and SFFs (aOR, 1.96; 95% CI, 1.22-3.13) were associated with a higher risk of prolonged hospital length of stay after controlling for age and flap loss.

Conclusions and Relevance

Findings of this cohort study suggest that perioperative outcomes associated with OCRFFFs compare favorably with those of FFFs and SFFs, with shorter operative times and lower rates of flap loss, 30-day readmissions, and prolonged hospital length of stay. However, patients undergoing SFFs represented a more medically and surgically complex population than those undergoing OCRFFFs or FFFs.

Aspirin, heparin and ischemia time in microvascular free flap surgery - their influence and an optimal anticoagulation protocol

BACKGROUND

Microvascular surgery has become a standardized technique for reconstruction of large tissue defects in Head and Neck Reconstructive Surgery. However, the main dreaded complications are thrombosis of blood vessels or major bleeding after surgery. Several different anticoagulation protocols have been established in the last decades to overcome these problems with varying degrees of success.

METHODS

Over a period of six years, a standardized anticoagulation protocol including acetylsalicylic acid (ASA) and unfractionated heparin (UFH) for direct intraoperative and postoperative administration was established, optimized and compared to a previously used non-standardized protocol. A total of 178 flap surgeries were included in the development and optimization process of the protocol.

RESULTS

ASA significantly increased the risk of complications when used for longer than 72 h (OR = 2.52; p = 0.002; 95% CI 1.39-4.59). Administration of UFH reduced flap loss (bolus: OR 0.68; p = 0.47; 95% CI 0.24-1.93; continuous UFH administration: OR = 0.61; p = 0.33; 95% CI 0.22-1.66), however doses greater than 500 IU/ h of UFH as continuous infusion increased the risk of complications. Reduction in ischemia time had no effect on the occurrence of complications.

CONCLUSION

Anticoagulation regimes in microvascular surgery can influence the postoperative complication rate. The optimal protocol should consist of a combination of ASA and UFH for the intraoperative and direct postoperative phase. Prolonged administration of ASA as well as doses &gt;500 IU/ h of UFH are to be avoided due to the increased complication rate.

Smoking and microvascular free flap perfusion in head and neck reconstruction: radial free forearm flaps and anterolateral thigh flaps

Head and neck reconstruction with microvascular free flaps is frequently performed in smokers. Smoking causes various alterations in the cardiovascular system. The aim of this study was to investigate the effects of smoking on flap perfusion as a critical factor for flap survival. A total of 370 patients reconstructed with a radial free forearm flap (RFFF) or anterolateral thigh flap (ALTF) in the head and neck region between 2011 and 2020 were retrospectively analyzed. Flap perfusion measurements with the O2C tissue oxygen analysis system were compared between nonsmokers, light smokers (< 20 pack-years), and heavy smokers (≥ 20 pack-years). The blood flow was intraoperatively equal in RFFFs (84.5 AU vs. 84.5 AU; p = 0.900) and increased in ALTFs (80.5 AU vs. 56.5 AU; p = 0.001) and postoperatively increased in RFFFs (114.0 AU vs. 86.0 AU; p = 0.035) and similar in ALTFs (70.5 AU vs. 71.0 AU; p = 0.856) in heavy smokers compared to nonsmokers. The flap survival rate was similar in nonsmokers, light smokers, and heavy smokers (97.3%, 98.4%, and 100.0%). Smoking partially increases rather than decreases microvascular free flap perfusion, which may contribute to similar flap survival rates in smokers and nonsmokers.

Outcomes of Re-exploration Procedures After Head and Neck Free Flap Reconstruction

This study was conducted to evaluate the outcomes of re-exploration procedures done after head and neck microvascular flap reconstructions. This is a retrospective review of 109 flaps in 106 patients (three patients had two flaps each) that underwent re-exploration procedures in 1001 consecutive free flap surgeries. The outcome was analysed in terms of the type of the flaps, re-exploration rate, flap salvage rate and overall flap success rate. Free radial forearm (RFF) was the commonest flap done (354, 35.3%). One hundred nine flaps underwent re-exploration procedures in 106 patients. Out of this, 79 flaps could be salvaged, and 30 flaps failed. There were also another ten flaps, which failed without any re-exploration. The overall re-exploration rate was 10.8%. The flap salvage rate was 72.4%. The overall flap success rate was 96.1%. Nearly three-fourths of the flaps with vascular compromise can be successfully salvaged with appropriate and timely intervention.

Osteomyocutaneous Free Fibula Flap Prevents Osteoradionecrosis and Osteomyelitis in Head and Neck Cancer Reconstruction

BACKGROUND

 Osteoradionecrosis (ORN) is one of the most severe complications of free fibula reconstruction after radiotherapy. The gold standard treatment of osteomyelitis involves extensive debridement, antibiotics, and sufficiently vascularized muscle flap coverage for better circulation. Therefore, we hypothesized that free fibula flap with muscle could decrease the risk of ORN.

METHODS

 This study consisted of 85 patients who underwent reconstruction with free fibula flap in head and neck cancer by a single reconstructive surgeon at Kaohsiung Veterans General Hospital over a period of 19 years (1998-2016). Patients with postoperative adjuvant radiotherapy were included in the study and were grouped by either free fibula osteocutaneous flap or free fibula osteomyocutaneous flap (with flexor hallucis longus muscle), and the incidence of ORN was compared.

RESULTS

 Of the 85 patients, 15 were reconstructed with osteocutaneous fibula flap and 70 were with osteomyocutaneous fibula flap. The rate of ORN or osteomyelitis was significantly lower in the muscle group (18.6%, n = 13/70 vs. 46.7%, n = 7/15, p = 0.020, Chi-square test).

CONCLUSION

 Vascularized muscle transfer increases perfusion of surrounding tissues and the bone flap, thereby decreasing the incidence of osteomyelitis or osteonecrosis.

Influence of time interval between endovascular intervention and free flap transfer on flap outcomes in critical limb-threatening ischemia: A retrospective analysis of 64 consecutive cases

BACKGROUND

Arterial revascularization and free flap reconstruction is safe and effective for limb salvage in patients with critical limb-threatening ischemia (CLTI). This study aimed to determine whether reconstruction outcomes were affected by the time interval between endovascular treatment and free flap transfer in lower extremity reconstruction for critical limb ischemia.

METHODS

Patients who underwent endovascular intervention and subsequent free flap reconstruction with >6 months of follow-up were reviewed. Those with wounds with oncological and traumatic etiologies were excluded. Patients' demographics, risk factors, details of microsurgical procedures, details of endovascular intervention, and flap outcomes were collected.

RESULTS

Overall, 64 consecutive patients (M:F = 50:14 and mean age, 57.3 [range, 29-82] years) were evaluated between November 2011 and October 2019. Angioplasty failed in three patients. For soft-tissue reconstruction, anterolateral free flaps were used most frequently (n = 54 and 84.4%). Flap-related complications developed in 12 cases, of which five cases included total flap necrosis. The interval between endovascular intervention and free flap transfer was not associated with flap loss in multivariate regression analysis. Patients with kidney transplants and higher serum creatinine were associated with total flap necrosis. Advanced age, failed angioplasty, and perfusion status of the pedal arch were associated with major flap complications.

CONCLUSION

The time interval between endovascular treatment and free flap reconstruction was not associated with flap complications. Free flap reconstruction of chronic wounds caused by CLTI can be safely planned regardless of the time duration from preoperative angioplasty.