Influence of repeated aspiration on viability of fat grafts: a comparative study

Survival Mechanisms and Retention Strategies in Large-Volume Fat Grafting: A Comprehensive Review and Future Perspectives

INTRODUCTION

Large-volume fat grafting is emerging as a promising technique in plastic and reconstructive surgery. However, the unpredictable graft volume retention rate remains a critical challenge. To address this issue, we need a profound understanding of the survival mechanisms following large-volume fat transplantation. This review summarizes known survival mechanisms and strategies to enhance graft retention.

METHODS

This review comprehensively examines the current literature on the survival mechanisms and retention strategies in large-volume fat grafting. A thorough literature search was conducted using PubMed, Medline and Google Scholar databases, focusing on studies published from 2009 to 2023.

CONCLUSION

In the current research on fat survival mechanisms, few have focused on large-volume fat grafting. This review provides an overview of the survival mechanisms specific to large-volume fat grafting and identifies a survival pattern distinct from that of small-volume fat grafting. Additionally, we have summarized existing strategies to improve graft retention across five stages (harvesting, processing, enrichment, grafting and post-graft care), analyzed their advantages and disadvantages and identified some of the most promising strategies.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors   www.springer.com/00266.

Modern Fat Grafting Techniques to the Face and Neck

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Understand age-related changes to the face and neck and pertinent anatomy and discuss important aspects of fat graft harvesting, processing, and infiltration. 2. Recognize key differences between common techniques for fat processing and infiltration and develop a plan for patients based on site-specific facial anatomical zones. 3. Appreciate the utility of fat grafting as an adjunct to other facial rejuvenating procedures such as face lift and blepharoplasty procedures and list the potential complications from fat grafting to the face and neck.

SUMMARY

Fat grafting to the face and neck aids in volume restoration, thereby addressing soft-tissue atrophy associated with the aging face, acquired conditions, or congenital malformations. Often, fat grafting may sufficiently restore facial volume alone or in conjunction with other facial rejuvenation procedures. Facial/neck fat grafting requires a systematic and thoughtful approach, with special care to atraumatic technique. This CME article covers the principles and techniques for modern facial fat grafting to the face and neck. Increasing data support the ability of autologous fat to produce significant and sustainable appearance-related changes. The authors follow the general principles of the Coleman technique for facial fat grafting and have observed tremendous success over the years. Other techniques for facial fat grafting are also discussed including microfat and nanofat processing. As the understanding of facial fat compartments continues to evolve, the authors may better predict fat grafting outcomes following augmentation. Finally, the technique described as "lipotumescence" has been successfully used in the breast and other regions of the body that have radiation damage and is discussed in this article specifically for the face and neck.

Surgical Decision Making in Autologous Fat Grafting: An Evidence-Based Review of Techniques to Maximize Fat Survival

Autologous fat grafting is an important tool in plastic surgery and is widely used for a variety of applications, both aesthetic and reconstructive. Despite an ever-increasing list of indications and extensive research over many years into improving outcomes, fat grafting remains plagued by incomplete and often unpredictable graft survival. Decisions made at each stage of surgery can potentially contribute to ultimate success, including donor site selection and preparation, fat harvest, processing, and purification of lipoaspirate, recipient site preparation, and delivery of harvested fat to the recipient site. In this review, we examine the evidence for and against proposed techniques at each stage of fat grafting. Areas of consensus identified include use of larger harvesting and grafting cannulas and slow injection speeds to limit cell damage due to shearing forces, grafting techniques emphasizing dispersion of fat throughout the tissue with avoidance of graft pooling, and minimizing exposure of the lipoaspirate to the environment during processing. Safety considerations include use of blunt-tipped needles or cannulas to avoid inadvertent intravascular injection as well as awareness of cannula position and avoidance of danger zones such as the subgluteal venous plexus. We believe that using the evidence to guide surgical decision-making is the key to maximizing fat grafting success. Level of Evidence: 4.

Are We Measuring What Really Counts?

Most published clinical research is faulty because of many reasons, one being faulty design. A remedy to this problem is the correct utilization of the PICOT (population, intervention, comparative intervention, outcome and time horizon) format in the design of a clinical research question. One element of the PICOT format, "outcome," has not been assessed adequately in aesthetic surgery. In this review, we found that in the last decade of all randomized controlled trials and comparative studies published in Aesthetic Surgery Journal, only about half specified a primary outcome. Regrettably, only 40% reported both a primary outcome and justification for choosing this outcome. This poses a credibility issue with the conclusions of the majority of published studies. There is an urgent need to develop critical outcome sets for aesthetic procedures to be utilized by future investigators. With such a critical outcome set, we will be able to pool the results of multiple studies on the same subject and reach conclusive results.

Supportive Use of Adipose-Derived Stem Cells in Cell-Assisted Lipotransfer for Localized Scleroderma

BACKGROUND

The authors aimed to analyze factors related to lipotransfer for localized scleroderma, and to explore the feasibility of cell-assisted lipotransfer for localized scleroderma treatment.

METHODS

Abdominal fat samples were taken from six scleroderma patients without corticosteroid therapy, five scleroderma patients with corticosteroid therapy, and 10 normal liposuction patients. Their quantity, morphology, and proliferation ability were measured. Blood flow was measured by laser speckle contrast imaging in localized scleroderma lesions and normal contralateral regions for eight localized scleroderma patients. Bleomycin-induced skin fibrosis nude mice were also used to investigate differences between lipotransfer and cell-assisted lipotransfer. Fat weight was measured, and expression of transforming growth factor (TGF)-β1 and type III collagen in the injected skin was determined by immunohistochemistry.

RESULTS

The number of stem cells from scleroderma patients with corticosteroid treatment was significantly reduced. Mean blood perfusion in localized scleroderma lesions was not significantly different than in the contralateral normal regions. In normal nude mice, there were no significant changes in TGF-β1 and type III collagen between the control, lipotransfer, and cell-assisted lipotransfer groups, whereas in bleomycin-induced skin fibrosis nude mice, lipotransfer and cell-assisted lipotransfer reduced TGF-β1 and type III collagen expression.

CONCLUSIONS

For scleroderma patients, fewer adipose-derived stem cells, because of a history of corticosteroid therapy and a local inflammatory microenvironment, are more important factors, whereas blood supply showed no significant change. Therefore, cell-assisted lipotransfer not only improves the survival rate of transplanted fat but also improves skin texture in bleomycin-induced skin fibrosis nude mice.