Fat Grafting for Neuropathic Pain After Severe Burns

Fat Grafting and Regenerative Medicine in Burn Care

Regenerative therapies such as fat grafting and Platelet Rich Plasma (PRP) have emerged as new options to tackle burn-related injuries and their long-term sequelae. Fat grafting is able to promote wound healing by regulating the inflammatory response, stimulating angiogenesis, favoring the remodeling of the extracellular matrix, and enhancing scar appearance. PRP can enhance wound healing by accelerating stages including hemostasis and re-epithelization. It can improve scar quality and complement fat grafting procedures. Their cost-effectiveness, minimal invasiveness, and promising results observed in the literature have made these tools as therapeutic candidates. The current evidence on fat grafting and PRP in acute and reconstructive burns is described and discussed in this study.

Neuropathic Pain After Burn Injury: A Severe and Common Problem in Recovery

OBJECTIVE

The aim of this study was to address the limited understanding of neuropathic pain (NP) among burn survivors by comprehensively examining its prevalence and related factors on a national scale using the Burn Model System (BMS) National Database.

BACKGROUND

NP is a common but underexplored complaint among burn survivors, greatly affecting their quality of life and functionality well beyond the initial injury. Existing data on NP and its consequences in burn survivors are limited to select single-institution studies, lacking a comprehensive national perspective.

METHODS

The BMS National Database was queried to identify burn patients responding to NP-related questions at enrollment, 6 months, 12 months, 2 years, and 5 years postinjury. Descriptive statistics and regression analyses were used to explore associations between demographic/clinical characteristics and self-reported NP at different time points.

RESULTS

There were 915 patients included for analysis. At discharge, 66.5% of patients experienced NP in their burn scars. Those with NP had significantly higher Patient-Reported Outcomes Measurement Information System 29 (PROMIS-29) pain inference, itch, anxiety, depression, and sleep disturbance scores and were less able to partake in social roles. Multiple logistic regression revealed male sex, % total body surface area, and moderate-to-severe pain as predictors of NP at 6 months. At 12 months, % total body surface area and moderate-to-severe pain remained significant predictors, while ethnicity and employment status emerged as significant predictors at 24 months.

CONCLUSIONS

This study highlights the significant prevalence of NP in burn patients and its adverse impacts on their physical, psychological, and social well-being. The findings underscore the necessity of a comprehensive approach to NP treatment, addressing both physical symptoms and psychosocial factors.

Pharmacotherapy for Keloids and Hypertrophic Scars

Keloids (KD) and hypertrophic scars (HTS), which are quite raised and pigmented and have increased vascularization and cellularity, are formed due to the impaired healing process of cutaneous injuries in some individuals having family history and genetic factors. These scars decrease the quality of life (QOL) of patients greatly, due to the pain, itching, contracture, cosmetic problems, and so on, depending on the location of the scars. Treatment/prevention that will satisfy patients' QOL is still under development. In this article, we review pharmacotherapy for treating KD and HTS, including the prevention of postsurgical recurrence (especially KD). Pharmacotherapy involves monotherapy using a single drug and combination pharmacotherapy using multiple drugs, where drugs are administered orally, topically and/or through intralesional injection. In addition, pharmacotherapy for KD/HTS is sometimes combined with surgical excision and/or with physical therapy such as cryotherapy, laser therapy, radiotherapy including brachytherapy, and silicone gel/sheeting. The results regarding the clinical effectiveness of each mono-pharmacotherapy for KD/HTS are not always consistent but rather scattered among researchers. Multimodal combination pharmacotherapy that targets multiple sites simultaneously is more effective than mono-pharmacotherapy. The literature was searched using PubMed, Google Scholar, and Online search engines.

Injectable Pectin-Alginate Hydrogels for Improving Vascularization and Adipogenesis of Human Fat Graft

Autologous fat grafting (AFG) is the most prevailing tool for soft tissue regeneration in clinics, although efficiency is limited to unpredictable volume resorption due to poor vascularization and eventual necrosis. This study sought to improve the AFG efficiency using a hydrogel as a carrier for human fat graft (F) with and without platelet-rich plasma (PRP). PRP is clinically well known for the local release of several endogenous growth factors and has been in clinical use already. A human-fat-graft-encapsulated pectin-alginate hydrogel (FG) was developed and characterized. PRP was added to F to develop a human fat graft with PRP (FP). FP was admixed with a pectin-alginate hydrogel to develop FGP. FG and FGP showed the smooth injectable, elastic, and shear-thinning properties. FG and FGP groups showed enhanced cell viability and proliferation compared to the control F in vitro. We also investigated the in vivo angiogenesis and neo-adipogenesis ability of F, FG, FGP, and FP in nude mice after subcutaneous injection. After 2 and 4 weeks, an MRI of the mice was conducted, followed by graft explantation. The explanted grafts were also assessed histologically and with immunohistochemistry (IHC) studies. MRI and histology results revealed better vascularity of the FG and FGP system compared to fat graft alone. Further, the IHC studies, CD 31, and perilipin staining also revealed better vasculature and adipogenesis of FG and FGP systems. These results indicate the enhanced angiogenesis and adipogenesis of FG and FGP. Thus, developed pectin-alginate hydrogel-based fat graft systems FG and FGP replenish the native microenvironment by mediating angiogenesis and adipogenesis, thereby maximizing the clinical outcomes of autologous fat grafting.

Preliminary results of alternative treatment for postmastectomy pain syndrome: stromal vascular fraction-enriched fat grafting

Postmastectomy pain syndrome (PMPS) is defined as chronic pain lasting more than 3 months after surgery. PMPS reduces the quality of life for patients and affects their daily life. Although the pathogenesis of PMPS has not been clearly elucidated, it is strongly suggestive of neuropathic pain caused by damage to the intercostobrachial nerve. While previous studies have used stromal vascular fraction (SVF)-enriched fat grafts in patients with neuralgia, few studies have used it for PMPS. Therefore, the present study evaluated the use of SVF-enriched fat, which includes adipose-derived stem cells with good differentiation capacity, in patients with PMPS to improve quality of life and reduce neuropathic pain. In three patients, the fat was mixed with concentrated SVF using a centrifuge and injected into the primary pain sites. After surgery, in all three cases, the subjective pain scale score decreased significantly over time.

Chronic Nerve Pain after Burn Injury: An Anatomical Approach and the Development and Validation of a Model to Predict a Patient's Risk

BACKGROUND

A model that predicts a patient's risk of developing chronic, burn-related nerve pain may guide medical and/or surgical management. This study determined anatomy-specific variables and constructed a mathematical model to predict a patient's risk of developing burn-related nerve pain.

METHODS

A retrospective analysis was conducted from 1862 adults admitted to a burn center from 2014 to 2019. One hundred thirteen patients developed burn-related nerve pain. Comparisons were made using 11 anatomy-specific locations between patients with and without burn-related nerve pain. The modified Delphi technique was used to select 14 potential risk variables. Multivariate regression techniques, Brier scores, area under the curve, Hosmer-Lemeshow goodness-of-fit, and stratified K-fold cross-validation was used for model development. Chronic pain was defined as pain lasting 6 or more months after release from the Burn Center.

RESULTS

Prevalence rates of burn-related nerve pain were similar in the development (6.1 percent) and validation (5.4 percent) cohorts [Brier score = 0.15; stratified K-fold cross-validation (K = 10): area under the curve, 0.75; 95 percent CI, 0.68 to 0.81; Hosmer-Lemeshow goodness-of-fit, p = 0.73; n = 10 groups]. Eight variables were included in the final equation. Burn-related nerve pain risk score = -6.3 + 0.02 (age) + 1.77 (tobacco use) + 1.04 (substance abuse) + 0.67 (alcohol abuse) + 0.84 (upper arm burn) + 1.28 (thigh burn) + 0.21 (number of burn operations) + 0.01 (hospital length-of-stay). Burn-related nerve pain predicted probability = 1 - 1/[1 + exp(burn-related nerve pain risk score)] for 6-month burn-related nerve pain risk score. As the number of risk factors increased, the probability of pain increased.

CONCLUSIONS

Risk factors were identified for developing burn-related nerve pain at 11 anatomical locations. This model accurately predicts a patient's risk of developing burn-related nerve pain at 6 months. Age, tobacco use, substance abuse, alcohol abuse, upper arm burns, thigh burns, the number of burn operations, and hospital length of stay represented the strongest predictors.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, III.

Adipose Grafting for Volume and Scar Release

ABSTRACT

Adipose fat grafting (AFG) is a popular technique used to add volume in the face, breasts, and other tissue deficient areas of the body. In terms of scar release, not only has fat provided additional soft tissue coverage but also the relief of pain in scars in those patients suffering from disease processes, such as complex regional pain syndrome with steroid-induced atrophy, burn scars, morphea, and lupus. The purpose of this article is to demonstrate the senior author's technique and outcomes of using AFG in the face and body for treating volume deficiency, atrophic scarring, and deformities.A retrospective chart review of 127 AFG procedures of the face and body from September 2006 to September 2019 was performed. Of these, 14 patients had scar releases performed with fat grafting of areas of scar contracture. Fat was harvested from the abdomen, thighs, and flanks using Toomey syringes or an enclosed power-assisted system with 3.7- or 3.0-mm cannulas. Grafting in small areas, such as the face, was performed with the 0.9-mm blunt cannula.The majority of AFG was completed in the face (45%), followed by breasts (22%), and scar contracture (16%). The mean volume of fat grafted in procedures involving the breasts, buttocks, and face was 102, 182, and 21 mL, respectively. For scar contracture, the mean volume was 38 mL and for deformations, 27 mL. Sixteen percent of the cohort required at least 1 additional AFG procedure to achieve satisfactory results. There were no major complications, such as skin loss, vascular injury, embolization, or blindness. Minor complications, such as erythema, edema, and hematoma at the fat harvest or graft site, did occur and were managed with local measures.Autologous fat grafting has consistently resulted in volume correction. In addition, in patients with autoimmune disorders, burn scars, and retracted scars, not only has there been volume correction but also decreased pain in the area of treatment. In our series of patients, we described our technique of AFG for the face, body, and scar contracture. Our results demonstrate that AFG remains an inexpensive, safe, and effective treatment option to achieve volume.

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

Despite recent advances in microsurgical techniques, functional recovery following peripheral nerve injury remains slow and inadequate. Poor peripheral nerve regeneration not only leaves patients with significant impairments, but also commonly leads to the development of debilitating neuropathic pain. Recent research has demonstrated the potential therapeutic benefits of adipose-derived stem cells, to enhance nerve regeneration. However, clinical translation remains limited due to the current regulatory burdens of the US FDA. A reliable and immediately translatable alternative is autologous fat grafting, where native adipose-derived stem cells present in the transferred tissue can potentially act upon regenerating axons. This review presents the scope of adipose tissue-based therapies to enhance outcomes following peripheral nerve injury, specifically focusing on their role in regeneration and ameliorating neuropathic pain.

Autologous Fat Grafting for the Treatment of a Painful Neuroma of the Hand: A Case Report and Review of Literature

Neuropathic pain caused by a neuroma can have a significant effect on daily life. Current surgical treatments include simple neuroma excision and proximal nerve stump relocation (into a muscle, vein, or bone). We describe a patient who presented with neuropathic pain, restricted to the dorsum of the right hand, and numbness of the dorsum of the radial half of the middle finger. The patient is a right-handed architect and due to the trauma could no longer shake hands for fear of pain. Her Tinel’s test was strongly positive. In 2015, she was diagnosed with a neuroma-in-continuity of the third digital nerve originating from the superficial branch of the radial nerve. At the time she was treated with an on-site Naropin injection and hand rehabilitation therapy, which ultimately alleviated the pain. Three years later she presented with pain progression whereupon we treated her exclusively with AFT. The patient was followed up for 12 weeks after the operation; the pain completely disappeared and the patient could shake hands again. After one year, she was still pain-free.

AFT is a new technique for the treatment of persistent neuropathic pain and numbness in the hand caused by blunt-trauma neuroma. Autologous fat grafting is a safe, effective, minimally invasive, and innovative therapeutic approach for the management of painful neuromas.

Autologous fat transfer to treat fibrosis and scar-related conditions: A systematic review and meta-analysis

BACKGROUND

Autologous fat transfer (AFT), also known as lipofilling, has been demonstrated to be more than just a filler. Through both mechanical dissection and local tissue remodelling mediated by stem cells, it is thought to improve scar quality, function and even pain. This paper aims to investigate the evidence regarding its safety and effectiveness for treating fibrosis and scar-related conditions.

METHODS

A literature search was performed in PubMed, Embase and the Cochrane Library to identify relevant studies. Extensive data extraction and standardization allowed conducting a meta-analysis.

RESULTS

Forty-five studies (3033 patients) provided sufficient data for meta-analysis. The AFT treatment resulted in significant increase in satisfaction scores of both patient and surgeon (p  =  0.001). Furthermore, a significant overall scar improvement was also found in the evaluation using the Patient and Observer Scar Assessment Scale, with the most notable effect in the scar stiffness (p<0.001) and pliability (p  =  0.004). In patients with severe pain, AFT resulted in a significant pain reduction of 3.7 points on the Visual Analogue Scale (p<0.001). Last, but not the least, the evidence suggests a significant recovery of radiotherapy-induced tissue damage (p  =  0.003) and function (p  =  0.012). On average, 1.4 procedures were required to achieve the desired result. Minor complications occurred in 4.8% of the procedures.

CONCLUSIONS

AFT is a promising treatment for fibrosis and scar-related conditions. Future research should focus on determining the long-term effects of AFT on fibrosis, pain and function. In addition, it would be crucial to quantify the mechanical and regenerative properties of fat as well as the effect of added supplements or stem cells.

Autologous adipose tissue grafting for the management of the painful scar

BACKGROUND AIMS

There is currently no definitive treatment for the painful scar. Autologous adipose tissue grafting (AATG) as a treatment option for scars has become increasingly popular and there is now an abundance of evidence in the literature that supports its application. Some studies suggest that human adipose tissue is a rich source of multipotent mesenchymal stromal cells. To our knowledge, there is currently no systematic literature review to date that examines the effectiveness of AATG for reducing pain in scars. Our novel systematic review aims to examine clinical studies on the use of AATG in the treatment of the painful scar.

METHODS

A literature search was performed using the following databases: PubMed, Cumulative Index to Nursing and Allied Health Literature, Web of Science, Medline, Cochrane library and Embase. The following key words and search terms were used: adipose stem cells, scar, pain, autologous fat grafting, scar management and neuropathic pain. Human interventional studies using autologous adipose tissue grafting for the treatment of painful scars including case series, case-control, cohort studies and randomized controlled trials were reviewed.

RESULTS

A total of 387 studies were found and 18 studies from January 1990 to January 2019 were identified as relevant for the purpose of this systematic review. Two studies were evidence level V, seven were evidence level IV, six were evidence level III, two were evidence level II and one was level I. A total of 337 scars were assessed in 288 patients for improvement in pain after scar treatment using adipose tissue grafting. An improvement in the analgesic effect was recorded in 12 of the 18 studies with adipose tissue grafting. A total of 233 of the 288 treated subjects responded with reduction in pain, whereas the rest did not. We carried out a pooled analysis of the studies and observed an odds ratio of 3.94 (P = 0.00001) when comparing pain reduction to no change in pain.

CONCLUSIONS

We conclude that AATG is a promising and safe modality for the treatment of the painful scar. There is an abundance of low-level evidence to support its use as an alternative treatment but there is a lack of high-level evidence at present to support its standard use. Future long-term randomized controlled trials with analgesic scores as the primary outcome measures are required to assess long-term efficacy.

Pregabalin in the reduction of pain and opioid consumption after burn injuries: A preliminary, randomized, double-blind, placebo-controlled study

BACKGROUND

The primary objective of the study was to evaluate the efficacy of 300 milligrams (mg) and 600 mg of pregabalin compared to placebo in the reduction of pain in patients with noncritical partial and full thickness burn injuries.

METHODS

A prospective, randomized, double-blinded, single center, placebo-controlled trial was conducted. Simple randomization method was used in this trial. After subjects met all the inclusion and none of the exclusion criteria, they were randomized and assigned to 1 of the 3 18-day treatments groups: Pregabalin 300 group, Pregabalin 600 group, or Placebo group. Demographics and clinical characteristics were recorded. The severity of pain was assessed by using the visual analog scale for pain intensity at baseline on day 3, day 9 ± 3, day 25 ± 7, day 90 ± 6, and day 180 ± 12.

RESULTS

A total of 54 subjects were randomly assigned, and 51 were included in the data analysis. Demographics and clinical characteristics did not differ significantly between the 3 groups. There was a statistically significant difference in pain between the Pregabalin 300 and Pregabalin 600 groups (P-value = .0260). The Pregabalin 300 group had 17.93 units (95% confidence interval: 1.83-34.04) higher pain scores on average than the Pregabalin 600 group, regardless of time. The adjusted P-value comparing 0 to 300 was .1618, while the adjusted P-value for 0 versus 600 was .5304. There was an overall difference in pain across time regardless of study group (P-value = <.0001). An overall difference in opioid consumption (P-value = .0003) and BSHS (P-value = .0013) across time regardless of study group was noted.

CONCLUSIONS

Pregabalin could be part of a promising multimodal analgesic regimen in noncritical burn population. Future placebo-controlled studies assessing the use of pregabalin in burn victim patients may further endorse our findings.

Combined Non-Ablative Laser and Microfat Grafting for Burn Scar Treatment

BACKGROUND

Burn scar treatment persists as an unsolved problem, involving thousands of affected patients disfigured for life.

OBJECTIVES

We sought to present our experience with the use of combined treatments for patients with burn scars.

METHODS

This was a case series report of the senior author's experience during 8 years utilizing the combined treatments of Fraxel Restore (fractional laser) and microfat graft injection for 288 patients with burn scars.

RESULTS

Laser treatment reduced scar intensity and attenuated skin irregularities and hyperpigmentation. All patients demonstrated marked improvement of skin texture and an increase in scar softness after 3 sessions of microfat grafting. However, the degree of improvement varied between patients and was related to the severity of the scar and the type of tissue. Overall, a 40% to 80% improvement was noted in our patients. All patients and their families expressed satisfaction with the results.

CONCLUSIONS

The combined treatment of Fraxel and microfat grafting is an effective technique for improving the appearance of a hypertrophic scar or keloid on burn patients. Fat tissue stem cells may have helped to repair the damaged skin.

LEVEL OF EVIDENCE: 4

Autologous Fat Transfer as a Treatment for Peripheral Neuropathic Pain without Apparent Cause

Neuropathic pain has a far-reaching effect on the daily lives of patients. Recently, autologous fat transfer (AFT) has demonstrated promising results in patients with painful scars or after neuroma excision. However, there is a subgroup of patients who do not show any apparent cause for the pain. We hypothesized that in these patients, AFT alone in the area around the affected nerve might lead to beneficial results. Patients with clearly demarcated neuropathic pain and who had exhausted all other treatment options were referred by a pain specialist. Fourteen patients who met the inclusion criteria received AFT in the area of the affected nerve. Pain scored on the visual analog scale, patient satisfaction, and quality of sleep were recorded before and after surgery. To investigate long-term effects, a second follow-up was planned at least 1 year later. Patient satisfaction was 93% after the first follow-up and 86% after more than 1 year. The mean VAS score was 7.4 before surgery and significantly decreased to 3.8 after autologous fat grafting (P < 0.0001) and 4.3 (P = 0.0017) at long-term follow-up. The quality of sleep improved in 50% of the patients, whereas the remainder indicated no difference. No complications were registered. The results show that AFT alone, even over a longer period of time and in patients refractory to multiple treatment modalities, can be useful to treat peripheral neuropathic pain without apparent cause. For definitive evidence, a larger prospective study is warranted.

Burn injury: Challenges and advances in burn wound healing, infection, pain and scarring

Severe burn injuries are the most traumatic and physically debilitating injuries affecting nearly every organ system and leading to significant morbidity and mortality. Early burn wound excision and skin grafting are common clinical practices that have significantly improved the outcomes for severe burn injured patients by reducing mortality rate and days of hospital stay. However, slow wound healing, infection, pain, and hypertrophic scarring continue to remain a major challenge in burn research and management. In the present article, we review and discuss issues in the current treatment of burn injuries; the advances and novel strategies developed in the past decade that have improved burn management; and also, pioneer ideas and studies in burn research which aims to enhance burn wound care with a focus on burn wound infection, pain management, treatments for scarring and skin tissue engineering.

Autologous Adipose-Derived Stem Cells Reduce Burn-Induced Neuropathic Pain in a Rat Model

Background: Burn scar pain is considered as neuropathic pain. The anti-inflammation and anti-neuroinflammation effects of adipose-derived stem cells (ASCs) were observed in several studies. We designed a study using a murine model involving the transplantation of autologous ASCs in rats subjected to burn injuries. The aim was to detect the anti-neuroinflammation effect of ASC transplantation and clarify the relationships between ASCs, scar pain, apoptosis and autophagy. Methods: We randomized 24 rats into 4 groups as followings: Group A and B, received saline injections and autologous transplantation of ASCs 4 weeks after sham burn, respectively; Group C and D, received saline injections and autologous transplantation 4 weeks after burn injuries. A designed behavior test was applied for pain evaluation. Skin tissues and dorsal horn of lumbar spinal cords were removed for biochemical analysis. Results: ASC transplantation significantly restored the mechanical threshold reduced by burn injury. It also attenuated local inflammation and central neuroinflammation and ameliorated apoptosis and autophagy in the spinal cord after the burn injury. Conclusion: In a rat model, autologous ASC subcutaneous transplantation in post-burn scars elicited anti-neuroinflammation effects locally and in the spinal cord that might be related to the relief of post-burn neuropathic pain and attenuated cell apoptosis. Thus, ASC transplantation post-burn scars shows the potential promising clinical benefits.

Fat Grafting for Burn, Traumatic, and Surgical Scars

Fat grafting provides a reliable modality with expanding usefulness in reconstructive plastic surgery. Owing to its mechanical and theorized regenerative properties, adipose tissue can improve scar qualities and scar related symptoms when grafted adjacent to or within a scar. In this article, the literature describing the effect of fat grafting on various types of scars, current scientific understanding of fat grafting for scars, and our current approach to the management of problematic burn scars are reviewed.

Peripheral Neuropathy and Nerve Compression Syndromes in Burns

Peripheral neuropathy and nerve compression syndromes lead to substantial morbidity following burn injury. Patients present with pain, paresthesias, or weakness along a specific nerve distribution or experience generalized peripheral neuropathy. The symptoms manifest at various times from within one week of hospitalization to many months after wound closure. Peripheral neuropathy may be caused by vascular occlusion of vasa nervorum, inflammation, neurotoxin production leading to apoptosis, and direct destruction of nerves from the burn injury. This article discusses the natural history, diagnosis, current treatments, and future directions for potential interventions for peripheral neuropathy and nerve compression syndromes related to burn injury.

The Future of Fat Grafting

Fat grafting has emerged as an important tool in the armamentarium of plastic surgeons. Its applications in aesthetic and reconstructive surgery continue to expand. However, its limitations (such as inconsistent survival) remain problematic. Recent research efforts have focused on tacking these issues with the use of platelet rich plasma, hypoxic preconditioning, hyperbaric oxygen, and the tissue engineering of scaffolds. In the future, as these laboratory discoveries are translated to clinical application, the beneficial uses of fat grafting will continue to increase.

Autologous fat grafting in keloids and hypertrophic scars: a review

Keloid and hypertrophic scars are unique human dermal fibroproliferative disorders of the injured skin and are associated with pain, itch and can cause functional limitations. A number of genetic, systemic and local factors have been identified in the formation of keloids and hypertrophic scars. Studies have shown that adipose-derived stem cells have angiogenic and antiapoptotic properties which has effects on wound healing, soft-tissue restoration and scar remodelling, and thus may have a role in managing keloid scaring. However, this role is not well described in the literature. A systemic review of available literature was thus undertaken, regarding the use of fat grafting in treatment of keloids and hypertrophic scarring. In total, 858 articles were identified, with ten studies ultimately fulfilling inclusion criteria. There were no studies specifically isolating the keloids and hypertrophic group of patients, and thus quantitative data were completely lacking from the literature. There were, however, individual cases described, and qualitatively encouraging clinical results were reported for the use of fat grafting on keloids and hypertrophic scars. Combined with the current theoretical and immunohistochemical understanding through other laboratory and animal studies, fat grafting may play a role in the treatment of keloids and hypertrophic scaring; however, specific evidence is currently lacking. The role for further research is clear.

Keloid and hypertrophic scars are difficult to treat conditions. Some studies have suggested that fat cells may have a role in managing these scars although this role is not well described in the literature. We perform a systematic review of available literature, examining the evidence for this.