Artificial intelligence for optimum tissue excision with indocyanine green fluorescence angiography for flap reconstructions: Proof of concept.

Background: Indocyanine green fluorescence angiography (ICGFA) is gaining popularity as an intraoperative tool to assess flap perfusion. However, it needs interpretation and there is concern regarding a potential for over-debridement with its use. Here we describe an artificial intelligence (AI) method that indicates the extent of flap trimming required. Methods: Operative ICGFA recordings from ten consenting patients undergoing flap reconstruction without subsequent partial/total necrosis as part of an approved prospective study (NCT04220242, Institutional Review Board Ref:1/378/2092), provided the training-testing datasets. Drawing from prior similar experience with ICGFA intestinal perfusion signal analysis, five fluorescence intensity and time-related features were analysed (MATLAB R2024a) from stabilised ICGFA imagery. Machine learning model training (with ten-fold cross-validation application) was grounded on the actual trimming by a consultant plastic surgeon (S.P.) experienced in ICGFA. MATLAB classification learner app was used to identify the most important feature and generate partial dependence plots for interpretability during training. Testing involved post-hoc application to unseen videos blinded to surgeon ICGFA interpretation. Results: Training:testing datasets comprised 7:3 ICGFA videos with 28 and 3 sampled lines respectively. Validation and testing accuracy were 99.9 % and 99.3 % respectively. Maximum fluorescence intensity identified as the most important predictive curve feature. Partial dependence plotting revealed a threshold of 22.1 grayscale units and regions with maximum intensity less then threshold being more likely to be predicted as "excise". Conclusion: The AI method proved discriminative regarding indicating whether to retain or excise peripheral flap portions. Additional prospective patients and expert references are needed to validate generalisability.

Staphylococcus Scalded Skin Syndrome-Induced Thrombosis Leading to Free Flap Complications: A Case Report and Review.

Staphylococcal scalded skin syndrome (SSSS) is a clinical term used for a spectrum of blistering skin conditions induced by the epidermolytic toxins of the Staphylococcus aureus bacteria. The complications of SSSS include thrombosis; however, the pathophysiology of this is still poorly understood. We present a case of free anterolateral thigh (ALT) flap failure in a patient as a result of widespread flap thrombosis associated with staphylococcal scalded skin syndrome (SSSS). This is the first reported case of free flap failure associated with SSSS. Free flap failure due to acquired prothrombotic conditions, such as infection, is a rare and potentially under-reported phenomenon. This article aims to further explore the role of both thrombophilias and provoked thrombotic events in free flap failure. A review of the literature will also be presented, and cases of free flap failure in patients with infection-induced vascular complications will be summarised.

Management of the intraoperative loss of microsurgical needles: A literature review and clinical survey.

Data on the incidence, management, and consequences of retained microsurgical needles in plastic and reconstructive surgery remains sparse. Research suggests that a mobile C-arm x-ray has a low detection rate for needles of size 8-0 or smaller. By means of a literature review, and survey, we aimed to investigate the current practice employed in the event of the intraoperative loss of a microsurgical needle. A literature review was conducted investigating the incidence, current management strategies, and consequences of retained microsurgical needles. This informed the questions included in a survey investigating management strategies employed in the intra-operative loss of a microsurgical needle. Results from the literature review show an overall low detection rate of microsurgical needles on imaging. Of the forty responders who completed the survey, 80% did not use a mobile C-arm x-ray to locate a missing microsurgical needle. Of the 20% that had done so, x-ray had been unsuccessful in locating the needle in all cases. Portable x-ray has a definite role to play in locating needles of size 7-0 or larger. This study suggests that suture needles of size 8-0 or smaller cannot be reliably detected on x-ray. Regarding management of this event, one should consider the risk of harm to the patient if retained, against the risk of searching for the needle. Based on the results of this work as well as existing published data, we advise against obtaining intra-operative x-rays in the event of a lost needle size 8-0 and above. Appropriate documentation should be completed.

Are Plastic Surgery Trainees Accurate Assessors of Their Own Microsurgical Skill?

Background: Microsurgery is a technically demanding surgical discipline with a steep learning curve. Trainees have faced several difficulties due to less hands-on theater time and pandemic-related limits on access to technical training. To overcome this, trainees engaged in self-directed training, which requires an accurate self-assessment of skill. This study aimed to assess the ability of trainees to accurately self-assess their performance while performing a simulated microvascular anastomosis. Methods: Novice and specialist plastic surgery trainees performed a simulated microvascular anastomosis on a high-fidelity chicken femoral vessel model. Each participant objectively rated the quality of their anastomosis using the Anastomosis Lapse Index (ALI). Two expert microsurgeons subsequently blindly rated each anastomosis. To determine the accuracy of self-evaluation, self-scores and expert-scores were compared using a Wilcoxon signed-rank test. Results: Twenty-seven surgical trainees completed the simulation, with a mean time to completion (TTC) of 40.3 minutes (range 14.2-106.0 minutes). For the entire cohort, the median ALI self-score was 4 (range 3-10), while the median ALI expert-score was 5.5 (range 2.5-9.5). There was a significant difference between the ALI self-score and the expert-score (p<0.001). When grouped by experience level, there was no significant difference between self-score and expert-score within the specialist group, while there was a significant difference within the novice group (p=0.001). Conclusion: These findings suggest that specialist trainees are accurate assessors of their own microsurgical skills, but novice trainees tend to overestimate their technical skills. While novice trainees can engage in independent self-directed microsurgical training, they should seek expert feedback to ensure targeted training.

The protein and miRNA profile of plasma extracellular vesicles (EVs) can distinguish feline mammary adenocarcinoma patients from healthy feline controls.

Feline mammary adenocarcinomas (FMA) are aggressive tumours with metastatic capability and limited treatment options. This study aims to investigate whether miRNAs associated with FMA tumours are secreted in extracellular vesicles (EVs) and whether they can potentially be used as a cancer biomarker in EVs from feline plasma. Tumours and matched tumour free margins from 10 felines with FMA were selected. Following a detailed literature search, RT-qPCR analyses of 90 miRNAs identified 8 miRNAs of interest for further investigation. Tumour tissue, margins and plasma were subsequently collected from a further 10 felines with FMA. EVs were isolated from the plasma. RT-qPCR expression analyses of the 8 miRNAs of interest were carried out in tumour tissue, margins, FMA EVs and control EVs. Additionally, proteomic analysis of both control and FMA plasma derived EVs was undertaken. RT-qPCR revealed significantly increased miR-20a and miR-15b in tumours compared to margins. A significant decrease in miR-15b and miR-20a was detected in EVs from FMAs compared to healthy feline EVs. The proteomic content of EVs distinguished FMAs from controls, with the protein targets of miR-20a and miR-15b also displaying lower levels in the EVs from patients with FMA. This study has demonstrated that miRNAs are readily detectable in both the tissue and plasma derived EVs from patients with FMA. These miRNAs and their protein targets are a detectable panel of markers in circulating plasma EVs that may inform future diagnostic tests for FMA in a non-invasive manner. Moreover, the clinical relevance of miR-20a and miR-15b warrants further investigation.

Microtools: A systematic review of validated assessment tools in microsurgery.

BACKGROUND: Microsurgery is a technically demanding aspect of surgery that is integral to a variety of sub-specialties. Microsurgery is required in high-risk cases where time is limited and pressure is high, so there is increasing demand for skills acquisition beforehand. The aim of this review was to analyse the available literature on validated microsurgical assessment tools. METHODS: Covidence was used to screen papers for inclusion. Keywords included 'microsurgery', 'simulation', 'end-product assessment' and 'competence'. Inclusion criteria specified simulation models which demonstrate training and assessment of skill acquisition simultaneously. Tools which were used for training independently of technical assessment were excluded and so were tools which did not include a microvascular anastomosis. Each assessment tool was evaluated for validity, bias, complexity and fidelity and reliability using PRISMA and SWiM guidelines. RESULTS: Thirteen distinct tools were validated for use in microsurgical assessment. These can be divided into overall assessment and end-product assessment. Ten tools assessed the 'journey' of the operation, and three tools were specifically end-product assessments. All tools achieved construct validity. Criterion validity was only assessed for the UWOMSA1 and GRS.2 Interrater reliability was demonstrated for each tool except the ISSLA3 and SAMS.4 Four of the tools addressed demonstrate predictive validity.4-7 CONCLUSION: Thirteen assessment tools achieve variable validity for use in microsurgery. Interrater reliability is demonstrated for 11 of the 13 tools. The GRS and UWOMSA achieve intrarater reliability. The End Product Intimal Assessment tool and the Imperial College of Surgical Assessment device were valid tools for objective assessment of microsurgical skill.

A comparative analysis of extracellular vesicles (EVs) from human and feline plasma.

Extracellular vesicles (EVs) are nanoparticles found in all biological fluids, capable of transporting biological material around the body. Extensive research into the physiological role of EVs has led to the development of the Minimal Information for Studies of Extracellular Vesicles (MISEV) framework in 2018. This framework guides the standardisation of protocols in the EV field. To date, the focus has been on EVs of human origin. As comparative medicine progresses, there has been a drive to study similarities between diseases in humans and animals. To successfully research EVs in felines, we must validate the application of the MISEV guidelines in this group. EVs were isolated from the plasma of healthy humans and felines. EV characterisation was carried out according to the MISEV guidelines. Human and feline plasma showed a similar concentration of EVs, comparable expression of known EV markers and analogous particle to protein ratios. Mass spectrometry analyses showed that the proteomic signature of EVs from humans and felines were similar. Asymmetrical flow field flow fractionation, showed two distinct subpopulations of EVs isolated from human plasma, whereas only one subpopulation was isolated from feline plasma. Metabolomic profiling showed similar profiles for humans and felines. In conclusion, isolation, and characterisation of EVs from humans and felines show that MISEV2018 guidelines may also be applied to felines. Potential comparative medicine studies of EVs may provide a model for studying naturally occurring diseases in both humans and felines.

A retrospective cohort study of cutaneous squamous cell carcinoma of the scalp: features of disease and influence of sociodemographic factors on outcomes.

BACKGROUND: Cutaneous squamous cell carcinoma (SCC) is an increasingly prevalent and potentially fatal disease with considerable implications if not recognized early and treated promptly. Several disease features contribute to a higher risk profile and adverse outcomes in affected patients. AIMS: Given the clinical observation that elderly males from rural communities often present with large SCCs of the scalp, we sought to investigate and describe features of disease and sociodemographic factors from a cohort of patients with scalp SCCs. METHODS: Histology reports of scalp primary SCCs were retrospectively assessed. Disease and demographic features were recorded. Descriptive statistics were generated, and statistical analyses (Fisher's exact, Mann-Whitney U and Spearman's rank test) were utilized to examine relationships between high-risk disease features and sociodemographic features. RESULTS: Ninety-three occurrences of scalp SCC in 61 patients were assessed. The average age at presentation was 78.81 years. Males were predominantly affected at a 14:1 ratio. Half of all tumours were greater than 2 cm (47/93 (50.54%)). The geographical distance from treatment was significantly associated with larger tumours at presentation. (rs = .34 P = 0.002). Recurrence and metastasis rates were determined amongst 188 patients with a primary scalp SCC, and low rates were observed (2.66% and 2.13%, respectively). CONCLUSIONS: Elderly males are inordinately affected by scalp SCC compared to females. Those living further from care exhibited larger tumours at presentation. Data from this study characterize features of SCC of the scalp and provide evidence to suggest that rural isolation may act as a mediator of high-risk presentation and larger tumour size.

The Use of Point of Care Ultrasound in Hand Surgery.

Point of care ultrasound (POCUS) is the use of ultrasound (US) imaging technology by non-sonographer, non-radiologist treating clinicians. Handheld US systems are increasing in popularity and becoming widely available and easily accessible to hand surgeons in clinical practice. Adapting POCUS into the repertoire of the hand surgeon can aid in the diagnosis of many common hand surgery presentations and shorten operative times. In this review, we outline the potential uses and advantages of incorporating POCUS into hand surgery practice incuding its use in emergencies such as trauma, infections, and foreign body localization, as well as elective presentations such as nerve compression, procedural guidance, and anesthesia. Finally, this review outlines the training and curriculum development required to ensure safe implementation of POCUS into a hand surgery practice.

Circulating Melanoma-Derived Extracellular Vesicles: Impact on Melanoma Diagnosis, Progression Monitoring, and Treatment Response.

Malignant melanoma, one of the most aggressive human malignancies, is responsible for 80% of skin cancer deaths. Whilst early detection of disease progression or metastasis can improve patient survival, this remains a challenge due to the lack of reliable biomarkers. Importantly, these clinical challenges are not unique to humans, as melanoma affects many other species, including companion animals, such as the dog and horse. Extracellular vesicles (EVs) are tiny nanoparticles involved in cell-to-cell communication. Several protein and genomic EV markers have been described in the literature, as well as a wide variety of methods for isolating EVs from body fluids. As such, they may be valuable biomarkers in cancer and may address some clinical challenges in the management melanoma. This review aimed to explore the translational applications of EVs as biomarkers in melanoma, as well as their role in the clinical setting in humans and animals. A summary of melanoma-specific protein and genomic EV markers is presented, followed by a discussion of the role EVs in monitoring disease progression and treatment response. Finally, herein, we reviewed the advantages and disadvantages of methods utilised to isolate EVs from bodily fluids in melanoma patients (human and animals) and describe some of the challenges that will need to be addressed before EVs can be introduced in the clinical setting.

A Novel Skin Closure Technique for the Management of Lacerations in Thin-Skinned Individuals.

Suturing thin, fragile skin, particularly in elderly patients, is often problematic and presents a challenge to many clinicians. We describe a novel technique that re-enforces the edges of such thin fragile skin, with the use of topical skin adhesive, 2-octyl cyanoacrylate (Dermabond™; Ethicon, Somerville, NJ). This allows secure suture placement and application of tension to facilitate wound closure.

Use of infrared thermography for the assessment of free flap perforators in autologous breast reconstruction: A systematic review.

Perforator-based flaps have in recent years become the mainstay of autologous breast reconstruction practice. Imaging modalities ranging from Doppler ultrasound to CT angiography demonstrate varying utility in the preoperative identification and localisation of perforators. Despite these available radiological investigations, finding and quantitatively assessing perforators remain a time-consuming and tedious process that is often complicated by a number of factors including variable anatomy prior surgery and body habitus. Thermographic imaging shows promise as a novel modality for preoperative localisation of perforator vessels. This review summarises the currently available evidence for its application in perforator mapping for abdominal-based autologous breast reconstruction. We discuss the development of the technology over the years, its current use, its advantages and how it may impact on reconstructive breast surgery.

Virtual Surgical Planning Computer-aided Design-guided Osteocutaneous Fibular Free Flap for Craniofacial Reconstruction: A Novel Surgical Approach.

Advancements and increased availability of radiological services have revolutionised our approach to oncological and reconstructive surgical practice. With an increasing demand for accuracy in diagnosis and improved oncological outcome, the requirement for precise application of radiological tools and the exploration of novel software has developed. This has led to the evaluation of modern technologies such as computer-aided design to enhance reconstructive surgery. Mandibular reconstruction following oncological resection using an osteocutaneous fibular free flap is now considered to be the gold standard reconstructive surgical approach, as this approach provides more satisfactory outcomes for both patients and reconstructive surgeons. Recent years have seen Irish reconstructive surgeons introduce computer-aided design pre-operative planning to operating theatres as means of improving cosmetic, functional and oncological outcome, yet the detailed, complex planning required pre-operatively is not well described. Herein, the purpose of this article was to demonstrate the precision and accuracy of virtual surgical planning computer-aided design (VSP-CAD) as a modern surgical approach to craniofacial reconstruction following surgical resection of an American Joint Committee on Cancer stage 4 oral carcinoma.

Determining the Effect of External Stressors and Cognitive Distraction on Microsurgical Skills and Performance.

Introduction: Microsurgery is an essential element of Plastic Surgery practice. There is a paucity of studies assessing the impact of stress and cognitive distraction on technical microsurgical performance. The ability to complete cognitive and technical skills in parallel has not been assessed in a microsurgical setting. Aim: To test the hypothesis that cognitive distraction and external stressors negatively affect microsurgical performance in a high fidelity simulation setting. Materials/Methods: Fourteen surgeons across all levels of training undertook 2 microsurgical skills sessions, 1 month apart. Session one established baseline microsurgical skill. In session two, skills were assessed with the introduction of realistic operative room cognitive distractions (ORDIs). Outcome measures were efficiency and accuracy, measured by Time to Completion (TTC) and Anastomosis Lapse Index (ALI), respectively. Key Results: Fourteen participants (6 novices, 5 plastic surgery specialist trainees and 3 consultants) completed both microsurgical skills sessions. In total, 28-microvascular anastomosis were analyzed. Mean baseline TTC for the group was 20.36 min. With cognitive distraction and external stress mean TTC decreased to 17.87 min. Mean baseline ALI score for the group was 3.32 errors per anastomosis. The introduction of cognitive distraction and external stress increased the mean to 4.86 errors per anastomosis. Total errors per anastomosis increased from 91 errors at baseline to 137 errors with cognitive distraction and external stress. Under stress, participants were more efficient but had reduced anastomotic accuracy. Conclusion: Under stress, surgeons were more efficient, this translated into faster completion of a microsurgical anastomosis. Efficiency, however, came at the expense of accuracy.