Free Flap Surgery Research Articles

Reliability of Postoperative Free Flap Monitoring with a Novel Prediction Model Based on Supervised Machine Learning.

Postoperative free flap monitoring is a critical part of reconstructive microsurgery. Postoperative clinical assessments rely heavily on specialty-trained staff. Therefore, in regions with limited specialist availability, the feasibility of performing microsurgery is restricted. This study aimed to apply artificial intelligence in postoperative free flap monitoring and validate the ability of machine learning in predicting and differentiating types of postoperative free flap circulation. Postoperative data from 176 patients who received free flap surgery were prospectively collected, including free flap photographs and clinical evaluation measures. Flap circulation outcome variables included normal, arterial insufficiency, and venous insufficiency. The Synthetic Minority Oversampling Technique plus Tomek Links (SMOTE-Tomek) was applied for data balance. Data were divided into 80%:20% for model training and validation. Shapley Additive Explanations were used for prediction interpretations of the model. Of 805 total included flaps, 555 (69%) were normal, 97 (12%) had arterial insufficiency, and 153 (19%) had venous insufficiency. The most effective prediction model was developed based on random forest, with an accuracy of 98.4%. Temperature and color differences between the flap and the surrounding skin were the most significant contributing factors to predict a vascular compromised flap. This study demonstrated the reliability of a machine-learning model in differentiating various types of postoperative flap circulation. This novel technique may reduce the burden of free flap monitoring and encourage the broader use of reconstructive microsurgery in regions with a limited number of staff specialists.

Head and Neck Reconstruction With 2-Stage External Pectoralis Major Myocutaneous Flap Transfer.

In head and neck surgery cases where skin is severely scarred or adhered to surrounding tissue, reconstruction can be difficult to perform using microsurgical tissue or conventional pedicled pectoralis major myocutaneous flap (PMMF) transfer given the risks, which include damage to major vessels when manipulating scarred skin. For such cases, we perform a 2-stage external PMMF transfer, whereby the PMMF is directly sutured to the defect over the neck skin (without manipulation the hardened skin), and the flap division is then performed secondarily. A total of 30 patients who had histories of radiotherapy (60-70 Gy) and prior neck dissection received the 2-stage external PMMF transfer procedure. Indications for the flaps included pharyngeal fistula closure in 12 patients, reconstruction for mandibular necrosis after radiotherapy in 8 patients, salvage surgery for partial or total necrosis of the free flap in 4 patients, and simultaneous reconstruction after tumor excision in 6 patients. Two patients underwent a second external PMMF transfer from the contralateral side because of postoperative complications, yielding a total of 32 flap transfers. Twenty-nine flaps showed complete flap survival, whereas 3 had partial necrosis. Other complications, despite complete flap survival, included large fistulas requiring additional surgery for fistula closure (1 patient) and small fistulas that were closed without requiring reoperation (7 patients). External PMMF transfer offers a safe, simple, and effective option in cases where free flap surgery is considered difficult or the risks associated with neck manipulation are high.

35. Microsurgical Practice with use of Smart Phone Camera as The Microscopic Field: A Training Protocol for Medical Students

Background: Accessibility to microsurgical equipment is a major barrier to proper training of surgeons prior to live patient free flap surgery. A novel technique is presented that uses a smartphone camera as the microscopic field, eliminating the need for an expensive operative microscope for surgical practice. Practice and repetition are the key components of surgical education. A convenient and cost effective simulation protocol could reduce the time frame of the microsurgery learning curve. Furthermore, the adoption of a microsurgical protocol that does not require access to a surgical microscope increases accessibility to aspiring surgeons and promotes repetition of microsurgical techniques. Methods: The Pocket Suture™ smartphone stand is a commercially available device that allows the smart phone camera to be used as magnification. The proposed education protocol included suture practice, vessel dissection, free tissue transfer in nonliving animal models, with vessel anastomosis and patency confirmation performed with a smartphone camera for field magnification. Video of the suturing technique allowed feedback from the mentor. Results: A progressive suturing protocol leading to the ability to perform microsurgical anastomosis on non living animal models was developed. The basic costs for the stand, instrument set and suture were less than $500. Conclusion: This protocol allows medical students interested in plastic surgery early exposure to advanced technical challenges that may solidify their specialty choice. The low cost eliminates many barriers to early microsurgery training. The protocol may also provide program directors another data point for resident recruitment in the post USMLE step one score era.

Seasonal Impact on Free Flap Surgery in Terms of Flap Loss and Wound Healing Disorders: A Retrospective Cohort Study of 158 Free Flaps.

(1) Background: Postoperative flap loss and wound healing disorders are severe complications after microsurgical free flap surgery. Despite multiple clinical observations, a possible influence of season and external temperature on outcome are largely missing. (2) Methods: Retrospectively, data were collected from 151 patients receiving microsurgical free flaps from March 2018 to August 2019. Patients were divided into two cohorts. The winter group includes all patients who underwent surgery from October 2018 to March 2019 and the summer group al those who underwent surgery from April 2018 to September 2018. Data included demographic information, pre-existing conditions, flap characteristics, and postoperative complications like flap losses and wound healing problems. External temperatures during the first 14 postoperative days were documented and the predictor of flap loss and wound healing disorders was detected. (3) Results: In the winter group (October-March; Ø 7.24 °C) 72 patients (46 female, 24 males; Ø 57.0 years) and in the summer group (April-September; Ø 18.79 °C) 81 patients (48 female, 33 males; Ø 56.0 years) received free flap surgery. There were no significant differences in demography (age: p = 0.593; gender: p = 0.419; BMI: p = 0.141). We found a significant increase in flap loss during summer (χ2(1) = 6.626; p = 0.010; V = 0.209) strengthened by logistic regression analysis (p = 0.037; Exp(B) = 9.655). Additionally higher average temperatures 14 days postoperatively represents another main driver (p = 0.023, Exp(B) = 1.161) for postoperative flap loss. (4) Conclusions: The data confirm a significantly higher postoperative flap loss in the summer group. This information may potentially contribute to optimization of perioperative management and planning of elective and semi-elective surgeries.

Free Flaps for Skin and Soft Tissue Reconstruction in the Elderly Patient: Indication or Contraindication

Increased lifespan and the improvement of medical treatment have given rise to research in reconstructive procedures in elderly patients. Higher postoperative complication rates, longer rehabilitation, and surgical difficulties remain a problem in the elderly. We asked whether a free flap in elderly patients is an indication or a contraindication and performed a retrospective, monocentric study. Patients were divided into two groups (YOUNG 0-59 years; OLD > 60 years). The endpoint was the survival of flaps and their dependence on patient- and surgery-specific parameters using multivariate analysis. A total of 110 patients (OLD n = 59) underwent 129 flaps. The chance of flap loss increased as soon as two flaps were performed in one surgery. Anterior lateral thigh flaps had the highest chance for flap survival. Compared with the lower extremity, the head/neck/trunk group had a significantly increased chance of flap loss. There was a significant increase in the odds of flap loss in linear relation to the administration of erythrocyte concentrates. The results confirm that free flap surgery can be indicated as a safe method for the elderly. Perioperative parameters such as two flaps in one surgery and transfusion regimens must be considered as risk factors for flap loss.

A retrospective analysis of pain and opioid usage in head and neck free flap reconstruction.

Investigate opioid usage and postoperative pain in patients undergoing head and neck free flap surgery. A retrospective review of 100 consecutive patients undergoing head and neck free flap reconstruction at two academic centers was performed. Data captured included demographics, postoperative inpatient pain, pain at postoperative visits, morphine equivalent doses (MEDs) administration, medication history, and comorbidities. Data were analyzed using regression models, χ 2 tests, and student's t-tests. Seventy-three percent of patients were discharged with opioid medication, with over half (53.4%) continuing to take opioids at their second postoperative visit, and over one-third (34.2%) continuing to take them around 4-monthpostoperatively. One out of every five (20.3%) opioid-naïve patients chronically took opioids postoperatively. There was a poor association between inpatient postoperative pain scores and daily MEDs administered (R 2 = 0.13, 0.17, and 0.22 in postoperative Days 3, 5, and 7, respectively). Neither preoperative radiotherapy nor postoperative complications were associated with an increase in opioid usage. For patients undergoing head and neck free flap operations, opioid medications are commonly used for postoperative analgesia. This practice may increase the chance an opioid-naïve patient uses opioids chronically. We found a poor association between MEDs administered and patient-reported pain scores, which suggests that standardized protocols aimed at optimizing analgesia while reducing opioid administration may be warranted. Level of Evidence: 3 (Retrospective cohort study).

Outcomes of perioperative vasopressor use for hemodynamic management of patients undergoing free flap surgery: A systematic review and meta-analysis.

This systematic review and meta-analysis investigates the objective evidence regarding outcomes in head and neck free flap surgeries using vasoactive agents in the perioperative period. A search was performed in PubMed, Cochrane, Web of Science, and Scopus databases. Inclusion criteria were clinical studies in which vasopressors were used in head and neck free flap surgery during the intraoperative and perioperative period. Eighteen studies (n=5397) were included in the qualitative analysis and nine (n=4381) in the meta-analysis. There was no difference in flap failure outcomes with perioperative vasopressor use in head and neck free flap surgery (n=4015, OR=0.93, 95% CI [0.60, 1.44]). When patients received vasopressors perioperatively, there was an associated decrease in flap-specific complications (n=3881, OR=0.69, 95% CI [0.55, 0.87]). Intraoperative vasopressor use does not negatively impact free tissue transfer outcomes in head and neck surgery and may reduce overall free flap complications.

Remote Monitoring System for Condition Management of Patients in Free Flap Surgery.

Free flap surgery is inconvenient because an attending physician must observe a patient's condition every day to ensure that normal tissue is restored within 72h after the surgery. To address this problem, this paper proposes a remote monitoring technology to observe a patient's condition in real time. To design a monitoring system, the camera consists of MCU board, DC-DC converter, alarm performance, Wi-fil module, and server, and the camera and MCU part is connected to the server through the wi-fi network. A camera obtains the images of the surgical site once every 2s, and the images are transmitted to the attending physician or nurse via Wi-Fi communication. The working distance between camera and surgical site is 56cm, and the viewing angle of a camera is 60° (radius). A video shooting test is also performed, in which the images are obtained once per hour between 17:00 and 08:00 the next day; the results show that high-quality images are obtained in the video shooting test. The imaging error is zero (0GB) in the video shooting test results. The imaging of the surgical site can be obtained by camera system, and the proposed method is that there no storage error occurs during the shooting process. In addition, the shooting performance has high velocity. It is possible to control the WD according to a patient's body via a holding manipulator used for the camera. The new method is expected to be used for remote patient management, for a wide range of procedures, in the medical field.

Harnessing the Power of Artificial Intelligence: Revolutionizing Free Flaps Monitoring in Head and Neck Tumor Treatment.

Treating head and neck tumors has undergone significant advancements, focusing on improving the patient's quality of life after treatment. Reconstructive surgical techniques with free flaps have been vital in restoring anatomy, function, and aesthetics, reducing morbidity from locoregional treatments. Monitoring free flaps is crucial to detect and address any vascular compromise that may lead to flap failure. Various monitoring techniques have been employed in free flap monitoring. However, standardizing them presents a challenge due to the need for more consensus among surgeons and variability in techniques, costs, and training requirements. Artificial intelligence (AI) shows promise in standardizing monitoring practices and reducing the operator-dependent variability. AI techniques have been explored to improve monitoring and early detection of complications in free flap surgeries, and they have shown high accuracy in analyzing images and predicting flap outcomes. Despite the potential benefits, implementing AI in free flap monitoring remains challenging. Standardization of input data, interpretation, cost, training, and accounting for patient and flap variability are crucial considerations. Further research, including multicenter studies, validation, and collaboration amongst clinicians, researchers, and AI experts is needed to overcome these challenges.

Analysis of Flap Failures in Microvascular Head and Neck Reconstructions: 11-Year Single-Center Results

AbstractBackground Free flap reconstruction is the gold standard in head and neck reconstructions. The current article analyzes failed free flaps in the head and neck region during an 11-year period in a single center aiming to discover factors that could be influenced in order to reduce the risk for flap failure.Methods During the 11-year study period, 336 patients underwent free flap reconstruction at Tampere University Hospital, Tampere, Finland. The patients' average age was 62 years (range 14–92 years). Note that 201 (61.5%) of the patients were women and 135 (38.5%) men. Medical records were reviewed for demographics, comorbidities, neoadjuvant and adjuvant therapies, free flap type, area of reconstruction, and intraoperative and postoperative complications. Statistical analyses were performed.Results Ten (3%) of the 336 free flaps failed. Patients' age, comorbidities, smoking, dosage of anticoagulation, free flap type, or the location of the defect did not influence the risk of flap failure. All lost flaps were postoperatively followed by clinical monitoring only. In contrast, 89% of all flaps had both Licox (Integra LifeSciences Corp, NJ) and clinical follow-up postoperatively. In six (60%) of the failed cases, a second free flap surgery was performed as a salvage procedure, with a survival rate of 83.3%.Conclusion Our free flap success rate of 97% is in accordance with that of other centers that perform head and neck reconstructions. According to our findings, free flap reconstructions can be successfully performed on elderly patients and patients with comorbidities. Smoking did not increase the flap loss rate. We encourage the use of other methods in addition to clinical monitoring to follow the flaps after head and neck free flap reconstructions. All flap types used have high success rates, and reconstruction can be conducted with the most suitable flaps for the demands of the defect.

A Comparison of Skin Graft Techniques with and without Plaster Back Slab Dressing in Reducing Donor Site Morbidity in Radial Forearm Free Flap Surgery - A Retrospective Study.

The radial forearm free flap (RFFF) is a commonly used free flap for the reconstruction of orofacial defects because of its versatility and reliability. The donor site is closed with either split or full-thickness skin graft, and one of the common donor site morbidities is skin graft failure. Various techniques to minimise skin graft failure were reported, and we compared the skin graft techniques with and without plaster back slab dressing in the radial forearm donor site. This is a retrospective study of 75 patients who had RFFF for reconstruction of oral cavity cancer at two different tertiary teaching hospitals in the United Kingdom between April 2015 and March 2020. Thirty-nine patients from Hospital one had volar back slap, bolster dressing and crepe bandage. In contrast, 36 patients from Hospital two had only pressure dressing without a back slab. The mean age of the study population was 60.65 (P = 0.274). In both groups, two patients had donor site complications. However, there was no significant difference in the donor site skin graft complications with a P = 0.662. There was no evidence in the literature to support an ideal bandage for skin graft at the RFFF donor site. Our comparison of two techniques of skin graft dressings with and without back slap did not show any difference in the skin graft take, and the volar back slab did not add any additional benefits. The simple use of foam as a bolster dressing without a back slab is ideal for the radial forearm free flap donor site.

Comparison of outcomes between early and delayed weight bearing following lower limb free flaps: an 18-month single-center study

Aim: Post-operative protocols following lower limb free flap surgery are not well defined, with a lack of consensus in the literature around limb dependency and weight bearing. The aim was to compare the complication rate for lower limb free flaps before and after the introduction of an enhanced lower limb free flap protocol with earlier dangling (day 3 vs. day 4) and weight bearing (day 5 vs. day 14) post lower limb free flap surgery. Methods: All lower limb free flaps between June 2020-January 2022 were identified from a departmental flap database. Patient data were collected from the comprehensive lower limb free flap database, medical notes, and electronic records. Patients prescribed an extended non-weight-bearing period due to the method of bone fixation were excluded. Results: A total of 37 patients, 15 pre- and 22 post-enhanced protocol, were identified for comparison. The mean age was 43 (17-72) with a M:F of 3:1. There was no difference in the type of flap reconstruction between groups, with the anterolateral thigh flap being the most common in both groups. No differences were identified in the number of complications related to dependency/weight bearing before and after the introduction of the enhanced protocol, with the mean length of stay reduced from 12.1 to 10.6 days (P = 0.34). Conclusion: The new enhanced protocol remains the standard of care in our unit, as we demonstrated a reduction in length of stay with no difference in complication rates following early weight bearing after lower limb free flap surgery.

Detecting flap compromise: an updated review of techniques to monitor microsurgical flaps post-operatively in breast reconstruction

Breast reconstructive surgery utilizing free tissue transfer has revolutionized the restoration of aesthetic and functional outcomes for patients. Even for the most routine free flap procedures, substantial hospital resources and costs are necessary. The effectiveness of free flap surgery, along with any reconstructive procedure, hinges upon meticulous patient selection, thorough pre-operative planning, well-informed peri-operative decision-making, and diligent post-operative monitoring and care for the patient. This article presents a review of standard clinical care monitoring techniques during the post-operative period, as well as the diverse strategies currently employed for post-operative flap monitoring.

Managing Oromandibular Hardware Failure after Free Flap Surgery.

Hardware failure after oromandibular reconstruction using free tissue transfer can delay additional therapies directed at cancer treatment and prevent patients from returning to normal oral function. Understanding and strict adherence to principles of rigid fixation is critical in preventing complications. Early surgical intervention for hardware exposure as well as utilization of locoregional flaps may prevent the need for more extensive revision surgery.

Evaluating Sensation Recovery in Noninnervated Free Flaps Used for Oral Reconstruction

Association between time and sensation recovery in noninnervated flaps remains unclear. Our goal was to evaluate the recovery of sensation in noninnervated free flaps used for oral reconstruction. A prospective cohort study was designed and consecutive patients undergoing noninnervated free flap surgery for oral reconstruction from a tertiary medical center were enrolled. The primary outcome variable was sensory recovery of light touch, pain, hot, and cold temperature. Sensory recovery was scored as per the test on the central portion and 4 peripheral sections of every flap. The Kaplan-Meier method was used to estimate the functional recovery at different time points and the association between clinicopathologic variables and sensation recovery at 24months after surgery was analyzed using the chi-squared test and logistic regression analysis. Eighty patients were included with a median age of 50years. At 3months postoperatively, no patients exhibited sensation recovery. Positive flap sensitivity began to appear mildly at 6months postoperatively and gradually increased for at least 24months. The 24-month sensation recovery rates of light touch, pain, and temperature were 70.0% (95% confidence interval [CI]: 59.2 to 78.9%), 42.5% (95% CI: 32.3 to 53.4%), and 33.8% (95% CI: 24.45 to 44.6%), respectively. In univariate analysis, 80.5% (95% CI: 66.0 to 89.8%) of the free radial forearm flaps showed light touch sensation recovery, which was statistically higher than 59.0% (95% CI: 43.4 to 72.9%) in other flaps (P=.036). Flap size ≤ 65cm2 predicted better pain sensation recovery with 57.5% (95% CI: 42.2 to 71.5%) compared to 27.5% (95% CI: 16.1 to 42.8%) in flap size > 65cm2 groups (P=.007). Logistic regression analysis confirmed flap size ≤ 65cm2 (P=.032, odds ratio=1.957, 95% CI: 1.034 to 4.389) and not smoking (P=.015, odds ratio=2.564, 95% CI: 1.673-5.482) offered better sensation recovery of pain and hot temperature, respectively. Sensation recovery in noninnervated free flaps was common and related to not smoking and flap size.

Simple and Easily Interpretable Flap Monitoring Method Using a Commercial Pulse Oximeter and a Widely Used Bedside Patient Monitor.

Background Various methods for monitoring after free flap surgery have been reported in the literature. Among them, pulse oximetry shows a sensitive reaction to vascular issues, and it is easy to interpret visually. However, previous reports used special equipment that was less commonly used and difficult to generalize. In this study, we used a commercial pulse oximeter and a widely used bedside patient monitor to monitor transplanted free tissue and lower extremities of healthy subjects with impaired circulation. Methods A reflectance pulse oximeter sensor was attached on the flap after free tissue transplantation. The sensor was connected to a bedside patient monitor, and the flap oxygen saturation (SpO2) levels and arterial waveforms were continuously monitored. Additionally, blood circulation disorder was induced in the lower limbs of healthy volunteers using pressure cuff inflation on the thigh, and the waveform and SpO2 levels on the pulse oximeter attached to the lower leg were monitored. Results Twenty-two patients were included in this study. No postoperative vascular issues were observed in any case. Pulse oximeters showed normal rhythmic wavelengths, and the flap SpO2 level ranged approximately >90%. The pulse oximeter waveform rapidly disappeared during arterial occlusion in the thigh pressure cuff inflation test, and the waveform flattened and the SpO2 level decreased slightly during venous congestion. Conclusion Flap monitoring using a commercially available pulse oximeter and a bedside patient monitor is a versatile, easy-to-interpret, and useful method. Changes in waveform and SpO2 levels appear during arterial and venous circulation disorders, and these changes can be differentiated.

Negative Pressure Wound Therapy in the Head and Neck: A Summary of Uses and Application Techniques.

Negative pressure wound therapy (NPWT) has had an expanded role in the management of complex wounds including its increasing use for complex wounds in the head and neck region. Challenges for use in the head and neck region include variations in surface topography and the proximity of sensitive mouth, nose, ear, eye, and tracheal openings. Despite these challenges, NPWT has been used in the head and neck immediately following free flap surgery, to prepare wounds for skin grafting or local flaps, to treat orocutaneous and pharyngocutaneous fistulas, to treat necrotizing and deep neck space infections, to temporize and palliate, and to treat chronic wounds with exposed bone and hardware among others. This review demonstrates the proven track record of successful uses of NPWT in the aforementioned scenarios, provides suggestions to improve efficacy, as well as an algorithm for use in certain clinical situations.

The effects of psychosocial determinants on post-operative complications of head and neck free flap patients

PurposeNot much is known about how pre-operative psychosocial factors affect head and neck free flap outcomes. Hence, the objective of the study is to determine if a patient's pre-operative self-perception and quality of life affect post-operative complications and hospital length of stay after free flap surgery. Materials and methodsThis was a prospective cohort study. Patients who underwent a free flap surgery at an academic tertiary care center between January 2021 and March 2022 were asked to fill out the Rosenberg Self Esteem Scale and the Short Form 36 Health Questionnaire before surgery. A chart review of their medical records was then performed. Analysis of the data was performed using Spearman Correlation, Fisher exact test, Mann-Whitney and Multivariate Logistic Regression on STATA 15. ResultsSixty-one patients (73.8 % male; mean [SD; range] age: 60.9 [14.0, 23.1–86.8]) who underwent free flap surgery agreed to participate in the study. Most of the participants were not Caucasian (59 %). The most common indication for surgery was malignancy (93 %). The post-operative complication rate was 34.4 % and included 3 hematoma (4.9 %), 3 free flap failure (4.9 %), 9 wound dehiscence (14.8 %), 10 salivary fistulas (16.4 %), and 3 aspiration pneumonia or chyle leak (4.9 %). There were no mortalities. The mean role limitations due to physical health subscore [SD; range], social functioning subscore, pain subscore, and general health subscore of the SF-36 were 61.9 [39.2, 0–100], 70.7 [27.5, 0–100], 62.1 [25.7, 0–100], and 67.8 [20.3, 20–100], respectively. On univariate analysis, decreased physical limitations, better social functioning, less pain and better general health were associated with fewer overall post-operative complications, but was not correlated with length of stay. This held true for social functioning and general health even in multivariate analysis accounting for age and smoking history. The mean Rosenberg Self Esteem Scale score was 24.3 [4.1, 13–30]. ConclusionsIn this study, patients with more limited social function and worse general health had more overall post-operative complications. It is important to continue to explore how pre-operative quality of life and other psychosocial factors can affect surgical outcomes.

29. A formal and multi-centre based protocol for rehabilitation post-fibular free flap surgery for patients undergoing major head and neck reconstruction

The fibular free flap (FFF) represents a workhorse in the reconstruction of major maxillofacial defects. This study was developed within a major UK head and neck unit with over 20 years’ high-volume experience in fibular free flap reconstruction (FFFR). The authors present a novel and formalised protocol for donor-site management and rehabilitation post-FFFR designed to optimise donor-site related outcomes.

85. Oral and maxillofacial cancer free flap surgery during the COVID-19 pandemic at Guy’s Hospital London

85. Oral and maxillofacial cancer free flap surgery during the COVID-19 pandemic at Guy’s Hospital London