Hyponatremia after Autologous Breast Reconstruction: A Cohort Study Comparing Two Fluid Management Protocols.

BACKGROUND: Perioperative fluid management is an important component of enhanced recovery pathways for microsurgical breast reconstruction. Historically, fluid management has been liberal. Little attention has been paid to the biochemical effects of different protocols. This study aims to reduce the risk of postoperative hyponatremia by introducing a new fluid management protocol. METHODS: A single-institution cohort study comparing a prospective series of patients was managed using a new "modestly restrictive" fluid postoperative fluid management protocol to a control group managed with a "liberal" fluid management protocol. RESULTS: One-hundred thirty patients undergoing microsurgical breast reconstruction, at a single institution during 2021, are reported. Hyponatremia is demonstrated to be a significant risk with the original liberal fluid management protocol. At the end of the first postoperative day, mean fluid balance was +2,838 mL (± 1,630 mL). Twenty-four patients of sixty-five (36%) patients had low blood sodium level, 14% classified as moderate-to-severe hyponatremia. Introducing a new, "modestly-restrictive" protocol reduced mean fluid balance on day 1 to +844 mL (±700) (p ≤ 0.0001). Incidence of hyponatremia reduced from 36 to 14% (p = 0.0005). No episodes of moderate or severe hyponatremia were detected. Fluid intake, predominantly oral water, between 8am and 8pm on the first postoperative day is identified as the main risk factor for developing hyponatremia (odds ratio [OR]: 7; p = 0.019). Modest fluid restriction, as guided by the new protocol, protects patients from low sodium level (OR: 0.25; confidence interval: 95%; 0.11-1.61; p = 0.0014). CONCLUSION: The original "liberal" fluid management protocol encouraged unrestricted postoperative oral intake of water. Patients were often advised to consume in excess of 5 L in the first 24 hours. This unintentionally, but frequently, was associated with moderate-to-severe hyponatremia. We present a new protocol characterized by early cessation of intravenous fluid and an oral fluid limit of 2,100 mL/day associated with a significant reduction in the incidence of hyponatremia and fluid overload.

Descriptive Study of Facial Motor Cocontractions During Voluntary Facial Movement in a Healthy Population: A New Hypothesis Contributing to Synkinesis.

Background: Motor overflow refers to involuntary movements that accompany voluntary movements in healthy individuals. This may have a role in synkinesis. Objective: To describe the frequency and magnitude of facial motor overflow in a healthy population. Methodology: Healthy participants performed unilateral facial movements: brow elevation, wink, snarl, and closed smile. Two reviewers analyzed the magnitude of each movement and cocontraction. Patterns of movements are described. Univariate analysis was used to assess the relationship between efficacy of unilateral facial control and the frequency and magnitude of cocontractions. Results: Eighty-nine participants completed the videos. Consensual mirror movements occurred in 96% of participants during unilateral eye closure and 86% during brow elevation. The most common associated movement was ipsilateral eye constriction occurring during snarl (90.1%). Improved unilateral facial control was associated with a decrease in frequency and magnitude of associated movements during brow elevation, wink, and snarl. Conclusion: This study showed stereotyped patterns of motor overflow in facial muscles that resemble those in synkinesis and become more evident as unilateral control of the face decreases.

Machine Learning Demonstrates High Accuracy for Disease Diagnosis and Prognosis in Plastic Surgery.

INTRODUCTION: Machine learning (ML) is a set of models and methods that can detect patterns in vast amounts of data and use this information to perform various kinds of decision-making under uncertain conditions. This review explores the current role of this technology in plastic surgery by outlining the applications in clinical practice, diagnostic and prognostic accuracies, and proposed future direction for clinical applications and research. METHODS: EMBASE, MEDLINE, CENTRAL and ClinicalTrials.gov were searched from 1990 to 2020. Any clinical studies (including case reports) which present the diagnostic and prognostic accuracies of machine learning models in the clinical setting of plastic surgery were included. Data collected were clinical indication, model utilised, reported accuracies, and comparison with clinical evaluation. RESULTS: The database identified 1181 articles, of which 51 articles were included in this review. The clinical utility of these algorithms was to assist clinicians in diagnosis prediction (n=22), outcome prediction (n=21) and pre-operative planning (n=8). The mean accuracy is 88.80%, 86.11% and 80.28% respectively. The most commonly used models were neural networks (n=31), support vector machines (n=13), decision trees/random forests (n=10) and logistic regression (n=9). CONCLUSIONS: ML has demonstrated high accuracies in diagnosis and prognostication of burn patients, congenital or acquired facial deformities, and in cosmetic surgery. There are no studies comparing ML to clinician's performance. Future research can be enhanced using larger datasets or utilising data augmentation, employing novel deep learning models, and applying these to other subspecialties of plastic surgery.

In vitro modelling of disease-induced changes in the diabetic wound fibroblast.

OBJECTIVE: Fibroblasts have been shown to play an increasingly important role within diabetic wounds. While several in vitro models of diabetic wound fibroblasts have been reported, none replicate the natural progression of the disease over time, recapitulating the acquisition of the diseased phenotype. Therefore, this study aimed to establish an in vitro model of the diabetic wound fibroblast through sustained exposure of healthy dermal fibroblasts to hyperglycaemia. METHOD: Primary human fibroblasts were isolated from discarded healthy skin tissue and were either exposed to normoglycaemic (control 5.5mM glucose) media or hyperglycaemic (25mM glucose) media for four weeks. Quantitative polymerase chain reaction was performed to measure the expression of inflammatory cytokines and chemokines. RESULTS: In the hyperglycaemia model, stromal cell-derived factor (SDF)-1 expression remained consistently downregulated across all four weeks (p<0.01), while monocyte chemoattractant protein (MCP)-1 (p<0.001), interleukin (IL)-8 (p=0.847) and chemokine (C-X-C motif) ligand 1 (CXCL1) (p=0.872) were initially downregulated at one week followed by subsequent upregulation between 2-4 weeks. CONCLUSION: This hyperglycaemia model may serve as a useful tool to characterise pathological changes in the diabetic wound fibroblast and help identify candidate therapeutic targets, such as SDF-1, that may reverse the pathology.

Laryngotracheal stenosis following intubation and tracheostomy for COVID-19 pneumonia: a case report.

Laryngotracheal stenosis (LTS) is a rare but serious condition characterized by narrowing of the airway. Iatrogenic injury from endotracheal intubation or tracheostomy insertion is the most common cause of LTS. We present the first reported experience of managing a patient diagnosed with subglottic stenosis (a subtype of LTS) following previous intubation and tracheostomy for coronavirus disease 2019 (COVID-19). This patient required an urgent surgical tracheostomy and subsequent referral to a tertiary airway surgery unit for definitive treatment, which included microlaryngoscopy, laser excision and balloon dilatation. This case highlights that LTS should be included in the differential diagnosis for patients re-presenting with breathing difficulties after prolonged intubation or tracheostomy for COVID-19. Furthermore, it raises the concern of a rise in the incidence of this condition and an increased burden on the few units specializing in airway surgery.

Hyaluronan in skin wound healing: therapeutic applications.

Hyaluronan is a vital constituent in effective skin wound healing. This polysaccharide is ubiquitous throughout the human body and has functional significance for tissue repair and remodelling. The importance of hyaluronan in the proliferative phase of healing is diverse, impacting on cell migration, proliferation, modification of the inflammatory response and on angiogenesis. As such, it holds therapeutic potential for a variety of clinical applications that range from facilitating effective wound healing to burns management and scarring. This overview of the multifaceted roles of hyaluronan considers its current applications to clinical practice in plastic surgery as well as the latest advances in research.

The future application of nanomedicine and biomimicry in plastic and reconstructive surgery.

Plastic surgery encompasses a broad spectrum of reconstructive challenges and prides itself upon developing and adopting new innovations. Practice has transitioned from microsurgery to supermicrosurgery with a possible future role in even smaller surgical frontiers. Exploiting materials on a nanoscale has enabled better visualization and enhancement of biological processes toward better wound healing, tumor identification and viability of tissues, all cornerstones of plastic surgery practice. Recent advances in nanomedicine and biomimicry herald further reconstructive progress facilitating soft and hard tissue, nerve and vascular engineering. These lay the foundation for improved biocompatibility and tissue integration by the optimization of engineered implants or tissues. This review will broadly examine each of these technologies, highlighting areas of progress that reconstructive surgeons may not be familiar with, which could see adoption into our armamentarium in the not-so-distant future.