Autologous fat grafting for nerve regeneration and neuropathic pain: current state from bench-to-bedside

Muscular branches from the ulnar artery are the basis for a pedicled partial flexor digitorum superficialis muscle flap

The feasibility of a pedicled flexor digitorum superficialis muscle flap was studied in 10 fresh cadavers. The number, length and distance from the flexion wrist crease of muscular branches from the ulnar artery in the distal 10 cm of the forearm were recorded. The mean number of muscular branches was 2.7 (range 1-4). The mean distance of the most distal branch was 35 mm (range 26-40) from the proximal wrist flexion crease. Its mean length was 20 mm (range 16-26). A partial muscle flap was raised on the most distal branch and transposed over the median nerve in the distal forearm. Dissection and transposition of this flap were feasible in all specimens. The reliable pattern of muscular branches to the flexor digitorum superficialis allows the elevation of a pedicled partial muscle flap that can cover the median nerve in the distal forearm.Level of evidence: V.

M2 Macrophage Polarization and Tissue Remodeling in Autologous Fat Grafting for Diabetic Skin Defects

Autologous adipose tissue was recognized as a promising therapeutic option for soft tissue defects owing to its regenerative potential and ability to facilitate tissue reconstruction. However, the mechanisms by which autologous fat grafting (AFG) promotes healing remain unclear, hindering its potential applications. This study aimed to investigate the distribution and phenotypic transition of infiltrating macrophages in transplanted adipose tissue, as well as their correlation with diabetic skin defect remodeling. Streptozotocin-induced diabetic rats with full-thickness dorsal skin defects were included in this study. The transplanted adipose tissue at the skin defects was collected and analyzed using flow cytometry to determine macrophage proportion and phenotype. The healing of skin defects was evaluated, and treatment was continued until day 14 as the designated endpoint of healing, followed by histopathologic examinations. Immunostaining with CD31 and lymphatic vessel endothelial receptor-1 was performed on wound tissues to analyze angiogenesis and lymphangiogenesis, respectively. Western blot and quantitative polymerase chain reaction analyses were used to assess the expression of the representative genes involved in the healing process. The results showed early polarization of M2 macrophages in the transplanted adipose tissue, concomitant with the upregulation of growth factors and downregulation of inflammatory factors. In vivo experiments revealed that AFG significantly promoted macrophage infiltration and M2 transformation in diabetic skin defects compared to the control groups, thereby promoting tissue extracellular matrix remodeling and lymphatic and vascular regeneration. However, the beneficial effects of AFG were inhibited by macrophage depletion. This study further demonstrated the potential of AFG for treating diabetic skin defects.

Autologous nanofat harvested from donor site of full-thickness skin or skin flap grafting for the treatment of early postburn scarring: a case series

Introduction

Postburn scarring often presents a specific reconstructive challenge from both functional and cosmetic perspectives. The purpose of this study was to investigate whether autologous nanofat harvested from the donor site of full skin or a skin flap can be reused for the treatment of early postburn scaring.

Methods

From July 2018 to April 2022, patients with early postburn scarring underwent scar reconstruction surgery with full-thickness skin or a skin flap for a contour deformity and/or scar contracture, and autologous nanofat grafting was performed during the same operation. The Vancouver Scar Score (VSS) and the itch and pain scores were evaluated at the preoperation time point as well as at 2-3 weeks and 3-months postoperation. A comparison was made among the same patients at different time points.

Results

A total of 17 patients, aged from 18 months to 62 years old were included in this analysis. The VSS was reduced from 10.00 ± 2.12 to 7.41 ± 1.277 at the 2-3-week postoperation time point, and to 5.53 ± 1.37 at the 3-month postoperation time point. The pain and itch score were reduced from 4.65 ± 1.37 and 6.35 ± 1.27, to 3.70 ± 1.10 and 4.94 ± 1.30 at the 2-3-week postoperation time point, and to 3.00 ± 1.28 and 3.94 ± 0.97 at the 3-month postoperation time point respectively. The VSS and pain and itch scores showed a statistically significant reduction (P < 0.05) at the 2-3-week and 3-month postoperative follow-ups compared with the preoperation time point.

Conclusion

Autologous nanofat grafting from donor sites of full thickness skin or skin flap may be a promising treatment for an early postburn scaring as it promotes scar softening, improves itching and pain within the scar. However, this is a small case series with only 17 patients. Further conclusions need to be drawn through expanded samples for randomized controlled clinical trials.

Lay Summary

Hypertrophic scarring is the most common complication after partial thickness burn injury, and the complex pathogenesis and prolonged dynamic process render treatments only marginally effective. In the past few decades, with the technological advances of liposuction and fat grafting, nanofat grafting has been used in a variety of surgical fields, including wound healing, scleroderma, facial rejuvenation, and neuralgia. However, the role of nanofat grafting is not well documented in the prevention and treatment of early postburn scarring. Full-thickness skin grafting or skin flap transplantation is the most common method for the reconstruction of a hypertrophic scaring until now. In the current study, we harvested subcutaneous fat during the preparation of the full-thickness skin or skin flap, prepared nanofat and injected it in the scar located at a nonsurgical site. Comparison of the pre- and postoperation scores for scar color, scar thickness, scar stiffness, and scar regularity showed that the postoperation scores were decreased significantly and that there was a significant improvement in scar pigmentation and thickness as well astheaesthetic outcome after treatment. Most importantly, reductions in the scores for pain and itching could be assessed objectively. It seems that the nanofat grafting is a potential method for prevention and treatment for early postburn scaring.

Application of Adipose-Tissue Derived Products for Burn Wound Healing

Burn injuries are a significant global health concern, leading to high morbidity and mortality. Deep burn injuries often result in delayed healing and scar formation, necessitating effective treatment options. Regenerative medicine, particularly cell therapy using adipose-derived stem cells (ASCs), has emerged as a promising approach to improving burn wound healing and reducing scarring. Both in vitro and preclinical studies have demonstrated the efficacy of ASCs and the stromal vascular fraction (SVF) in addressing burn wounds. The application of ASCs for burn healing has been studied in various forms, including autologous or allogeneic cells delivered in suspension or within scaffolds in animal burn models. Additionally, ASC-derived non-cellular components, such as conditioned media or exosomes have shown promise. Injection of ASCs and SVF at burn sites have been demonstrated to enhance wound healing by reducing inflammation and promoting angiogenesis, epithelialization, and granulation tissue formation through their paracrine secretome. This review discusses the applications of adipose tissue derivatives in burn injury treatment, encompassing ASC transplantation, as well as the utilization of non-cellular components utilization for therapeutic benefits. The application of ASCs in burn healing in the future will require addressing donor variability, safety, and efficacy for successful clinical application.

Expanding Our Role in Headache Management: A Systematic Review and Algorithmic Approach to Surgical Management of Postcraniotomy Headache

BACKGROUND

Chronic postcraniotomy headache (PCH) is common and debilitating. Unfortunately, the literature on this topic is sparse without clear management algorithms. Possible etiologies of PCH include nerve injury and/or entrapment, hardware, dural adhesions, or musculoskeletal injury. The purpose of this study was to present the results of both a systematic review of the literature and a single-center case series, both of which informed the development of a novel treatment algorithm that may be applied to this patient population.

METHODS

Using Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, we performed a systematic review of the literature, identifying articles describing the surgical management of PCH. A retrospective chart review was performed to identify patients who met the criteria for PCH treated at our institution. A patient's history and physical examination determined the etiology and management, and pain severity scores were the primary outcome measured.

RESULTS

Nineteen articles encompassing 131 patients described surgical management techniques for PCH. 83 patients (63.3%) had complete resolution of pain (χ2 = 52.1, P < 0.0001). At our institution, 19 patients underwent surgical management for PCH. A significant reduction in pain scores from 7.57 to 2.16 (P < 0.001) was demonstrated, and 84 percent of patients achieved complete or significant pain reduction.

CONCLUSIONS

Through a literature review and our own case series, we demonstrate that surgical management of PCH can achieve remarkable results. Plastic surgeons, with their expanding role in treating migraine and headaches, are well suited to manage these patients. We present an algorithmic approach to simplify the management of this common and debilitating condition.

Safety and Aesthetics of Autologous Dermis-Fat Graft after Parotidectomy: A Multidisciplinary Retrospective Study

(1) Background: In surgical procedures for maxillofacial tumours, it is challenging to preserve functional and cosmetic properties in the affected patients. The use of fat grafting is considered as a valuable alternative to overcome postoperative aesthetic asymmetry problems. (2) Methods: In this study, we enrolled thirty patients with parotid gland tumours in which a partial or complete parotidectomy was performed with positioning in the parotid bed of autologous dermis-fat grafts. We evaluated the satisfaction rate of the patients and the objective efficacy in solving the deformity by comparing MRI data before and after surgery. (3) Results: Twenty-six patients showed a satisfying cosmetic result with proper facial symmetry between the affected side and the healthy one. Two patients presented mild postsurgical complications such as haematomas, and two patients reported temporary weakness of the facial nerve related to the parotidectomy. (4) Conclusions: Based on the imaging data obtained via MRI before and after surgery, we can assess that the employment of fat grafts in parotidectomy surgical procedures gives good cosmetic results and does not affect the post operative management and follow up of oncologic patients.

Heparin-Based Hydrogel Micropatches with Human Adipose-Derived Stem Cells: A Promising Therapeutic Approach for Neuropathic Pain Relief

This study explores the therapeutic efficacy of heparin-based hydrogel micropatches containing human adipose-derived stem cells (hASCs) in treating neuropathic pain caused by nerve damage. Our results showed that hASCs exhibited neuroregenerative and pain-relieving effects when used with heparin-based hydrogel micropatches in the neuropathic pain animal model. The use of this combination also produced enhanced cell viability and nerve regeneration. We conducted various neurological behavioral tests, dynamic plantar tests, histological examinations, and neuroelectrophysiological examinations to confirm the therapeutic effect. Our findings suggest that this approach could maximize therapeutic efficacy and improve the quality of life for patients suffering from neuropathic pain.

Autologous fat grafting to the paravertebral space seems to prevent the postherpetic neuralgia-A single-arm pilot study

INTRODUCTION

Postherpetic neuralgia (PHN) is one of the most common complications of Herpes zoster (HZ), yet the mechanism and the treatment for PHN remains elusive. We first performed this feasibility study to verify the safety and efficiency of autologous fat grafting into the paravertebral space in early HZ to prevent PHN.

METHODS

Patients suffering from HZ with a rash in chest, back, or abdomen were arranged for autologous fat grafting to the paravertebral space. The primary endpoint was the incidence of PHN, which was defined as persistence pain in the affected dermal area in 12 weeks after fat grafting. Secondary endpoints including patient-reported changes in pain intensity, assessed pain threshold and the quality of life during follow-ups.

RESULTS

Eight patients accept the intervention and completed all follow-ups. Most patients report immediate pain relief after injection, one patient has a mild to moderate dizzy symptom after injection. No other short- or long-term adverse events occurred. For primary outcome, all patients have a timely reduced pain intensity, with no PHN events occurred, as all patients report pain intensity ≤3 in the VAS scale in 3 months after treatment. For electrical pain threshold, we identify that fat grafting differentially increases sensation and pain threshold in HZ area and healthy skin of patients. Besides, our results indicate significant improvement in patients' life quality decrease in analgesic consumption.

DISCUSSION

Autologous fat transplantation to the paravertebral space is a safe and feasible technique in preventing PHN from HZ in a rash. Further randomized controlled trial to investigate the actual long-term benefice of autologous fat grafting to the paravertebral space in preventing PHN is needed.

TRIAL REGISTRATION

ChiCTR, (ChiCTR1900025416); registered August 26, 2019.

Exploring the Physicochemical, Electroactive, and Biodelivery Properties of Metal Nanoparticles on Peripheral Nerve Regeneration

Despite the advances in the regeneration/rehabilitation field of damaged tissues, the functional recovery of peripheral nerves (PNs), especially in a long gap injury, is considered a great medical challenge. Recent progress in nanomedicine has provided great hope for PN regeneration through the strategy of controlling cell behavior by metal nanoparticles individually or loaded on scaffolds/conduits. Despite the confirmed toxicity of metal nanoparticles due to long-term accumulation in nontarget tissues, they play a role in the damaged PN regeneration based on the topography modification of scaffolds/conduits, enhancing neurotrophic factor secretion, the ion flow improvement, and the regulation of electrical signals. Determining the fate of neural progenitor cells would be a major achievement in PN regeneration, which seems to be achievable by metal nanoparticles through altering cell vital approaches and controlling their functions. Therefore, in this literature, an attempt was made to provide an overview of the effective activities of metal nanoparticles on the PN regeneration, until the vital clues of the PN regeneration and how they are changed by metal nanoparticles are revealed to the researcher.

Treating Pain and Fat Necrosis after Breast Cancer Surgery with Fat Grafting: Is one Session Enough?

BACKGROUND

Chronic pain after breast cancer surgery is affecting up to 60% of patients, causing significant morbidity to patients. Lately, fat grafting has been applied as a therapy for chronic neuropathic pain.

METHODS

We report a series of eighteen patients, who were treated for pain after breast cancer surgery. Twelve patients had a breast conserving therapy, two a mastectomy and four an autologous flap-based reconstruction. While most presented with neuropathic pain, six patients had fat necrosis in their history. Most patients presented with severe pain (77%) and were treated with fat grafting sessions, performed by water-assisted liposuction.

RESULTS

All patients responded to the interventions; the median number of fat grafting sessions was 2, the median duration of the interventions was 4 months, and the median follow-up period was 56.5 months. The median pain prior to the fat grafting procedure had an intensity of 8 (range 7-9) numeric rating scale points; after the first intervention, this was reduced to 4 (range 2.3-5.8); and after the second intervention, it was down to 2 (range 0.8-3.3). Patients with pain intensities of 4-5 had a good chance of achieving analgesia after one session.

CONCLUSIONS

Fat grafting could be a new treatment modality for symptomatic fat necrosis: complete or partial suction of the necrosis and/or fat grafting around the necrosis to reduce inflammation and pain. Fat grafting proved a valuable tool, reducing pain or even achieving analgesia after breast cancer surgery presenting with a highly favorable risk-benefit ratio.

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.

Role of adipose tissue grafting and adipose-derived stem cells in peripheral nerve surgery

The application of autologous fat grafting in reconstructive surgery is commonly used to improve functional form. This review aims to provide an overview of the scientific evidence on the biology of adipose tissue, the role of adipose-derived stem cells, and the indications of adipose tissue grafting in peripheral nerve surgery. Adipose tissue is easily accessible through the lower abdomen and inner thighs. Non-vascularized adipose tissue grafting does not support oxidative and ischemic stress, resulting in variable survival of adipocytes within the first 24 hours. Enrichment of adipose tissue with a stromal vascular fraction is purported to increase the number of adipose-derived stem cells and is postulated to augment the long-term stability of adipose tissue grafts. Basic science nerve research suggests an increase in nerve regeneration and nerve revascularization, and a decrease in nerve fibrosis after the addition of adipose-derived stem cells or adipose tissue. In clinical studies, the use of autologous lipofilling is mostly applied to secondary carpal tunnel release revisions with promising results. Since the use of adipose-derived stem cells in peripheral nerve reconstruction is relatively new, more studies are needed to explore safety and long-term effects on peripheral nerve regeneration. The Food and Drug Administration stipulates that adipose-derived stem cell transplantation should be minimally manipulated, enzyme-free, and used in the same surgical procedure, e.g. adipose tissue grafts that contain native adipose-derived stem cells or stromal vascular fraction. Future research may be shifted towards the use of tissue-engineered adipose tissue to create a supportive microenvironment for autologous graft survival. Shelf-ready alternatives could be enhanced with adipose-derived stem cells or growth factors and eliminate the need for adipose tissue harvest.

Pathophysiological and Neuroplastic Changes in Postamputation and Neuropathic Pain: Review of the Literature

Despite advancements in surgical and rehabilitation strategies, extremity amputations are frequently associated with disability, phantom limb sensations, and chronic pain. Investigation into potential treatment modalities has focused on the pathophysiological changes in both the peripheral and central nervous systems to better understand the underlying mechanism in the development of chronic pain in persons with amputations.

Methods

Presented in this article is a discussion outlining the physiological changes that occur in the peripheral and central nervous systems following amputation. In this review, the authors examine the molecular and neuroplastic changes occurring in the nervous system, as well as the state-of-the-art treatment to help reduce the development of postamputation pain.

Results

This review summarizes the current literature regarding neurological changes following amputation. Development of both central sensitization and neuronal remodeling in the spinal cord and cerebral cortex allows for the development of neuropathic and phantom limb pain postamputation. Recently developed treatments targeting these pathophysiological changes have enabled a reduction in the severity of pain; however, complete resolution remains elusive.

Conclusions

Changes in the peripheral and central nervous systems following amputation should not be viewed as separate pathologies, but rather two interdependent mechanisms that underlie the development of pathological pain. A better understanding of the physiological changes following amputation will allow for improvements in therapeutic treatments to minimize pathological pain caused by amputation.

Clinical and Patient-Reported Outcomes of 19 Patients Undergoing Clitoral and Labial Reconstruction After Female Genital Mutilation/Cutting

BACKGROUND

Female genital mutilation/cutting (FGM/C) is the intentional alteration, removal, or injury of female genitalia for non-medical reasons. Approximately 200 million females have been victims of FGM/C, and genital reconstructive procedures are increasing in demand.

OBJECTIVES

The objectives of this study were to assess clinical and patient-reported outcomes after FGM/C reconstruction to help guide treatment practices.

METHODS

Adult patients undergoing anatomic reconstruction after FGM/C were retrospectively identified. Outcomes included clitoral, labial, and donor site surgical site occurrences (SSO) and the need for revision operations. Patient-reported outcomes were assessed using an adapted version of the Female Sexual Function Index (FSFI), a validated outcomes instrument that assesses sexual function through 6 domains, with each domain having a maximum score of 6.

RESULTS

Nineteen patients were identified in our review. Patients presented for reconstruction due to dyspareunia, inability to orgasm, chronic infections, to normalize appearance, and/or to "feel normal." There were no SSOs and two revision operations for adhesions. 74% of patients completed the FSFI postoperatively. Despite most patients seeking repair for inability to orgasm and/or dyspareunia, the median scores for these domains were 4.6 and 5.2. Patients' desire to engage in sexual activity scored lowest (3.9), and patients reported concerns over the appearance of their genitalia (50%) that affected self-confidence (85.7%).

CONCLUSION

FGM/C reconstruction is safe and contributes to improvements in physical sexual health. Psychological trauma may contribute to lessened sexual desire and self-confidence even after reconstruction. Multidisciplinary treatment is important to address the long-term psychological effects of this practice.

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 .