Perineural fat grafting in the treatment of painful end-neuromas of the upper limb: a pilot study

Minimally invasive scar release by autologous adipose tissue transfer for post-traumatic neuropathic pain

Introduction

Addressing post traumatic lower limb neuropathic pain is challenging across medical specialties. To address this potentially devastating condition, several invasive and non-invasive approaches have been proposed with inconsistent results. Adipose fat transfer (AFT), also known as fat grafting, is a regenerative medicine technique in which a patient's own fat is harvested from one area of the body (usually through liposuction) and then injected into another area for various purposes, such as aesthetic contour enhancement or reconstruction and regeneration of scarred tissues.

Methods

We analyze the effects of fat grafting for neuropathic pain combined with neuroma excision (hybrid technique, hAFT) or alone (AFT). A retrospective review was conducted on 22 patients with neuropathic lower limb pain, after trauma or orthopedic surgery treated with hAFT (n = 9) or AFT (n = 13).

Results

Reduction in VAS scale more than 50 % was observed in 6 patients (66 %) treated with hybrid technique and in eleven patients (85 %) treated with AFT alone. Among these, complete pain reduction (>91 %) was achieved in 33.3 % of hAFT and 54 % of AFT technique. A 3.2 points reduction in VAS was found in the hAFT group versus 5.8 points in the AFT group (p = 0.035).

Conclusion

This pioneering use of AFT emerges as a minimally invasive breakthrough, promising significant improvement in reconstructing scarred subcutaneous tissue and managing neuropathic pain.

Treatment of Iatrogenic Saphenous Neuroma after Knee Arthroscopy with Excision and Allograft Reconstruction

The treatment of postoperative, painful sensory neuromas is an ongoing challenge for surgeons. Here, we describe a technique for treatment with excision and allograft reconstruction and report on early results of its use in treating painful saphenous neuromas after knee arthroscopy.

Methods

A retrospective review of a single surgeon's peripheral nerve clinic from January 1, 2013, to December 31, 2019, was conducted to identify post-knee arthroscopy saphenous neuroma cases in which reconstruction with processed human nerve allograft distally implanted into healthy muscle belly was performed. We examined the outcomes for each patient, including subjective pain self-assessment and need for further surgical treatment.

Results

In total, 9 cases were identified, with patient ages ranging from 21 to 74 years. The average time to referral to peripheral nerve clinic was 31 months (range: 4-143 months). Upon exploration, all nerves were found to have a neuroma in continuity. Six of the 9 patients reported subjective improvement through final follow-up. Three of the 9 patients reported initial improvement, with recurrence of pain at/near the site of the neuroma. The average follow-up time was 9 months (range: 1-21 months).

Conclusions

Here, we report on a novel technique of using a processed human nerve allograft after neuroma resection to provide an organized environment for bridging regenerated axons into muscle tissue. We also describe our early results using this technique to treat iatrogenic saphenous neuromas after knee arthroscopy. Results are encouraging, with 6 of the 9 patients experiencing subjective reduction in pain at final follow-up.

Secondary release of the peripheral nerve with autologous fat derivates benefits for functional and sensory recovery

The reconstruction of nerve continuity after traumatic nerve injury is the gold standard in hand surgery. Immediate, tension-free, end-to-end nerve suture ensures the best prognosis. The recovery is mostly promising; however, in a few cases, insufficient outcomes in motor or sensory function are observed. Intra- and extra-fascicular scarring accompanies the nerve regeneration process and limits final outcomes. Secondary nerve release in those cases is recommended. Unfortunately, scarring recurrence cannot be eliminated after secondary revision and neurolysis. The supportive influences of mesenchymal stem cells in the process of nerve regeneration were observed in many preclinical studies. However, a limited number of studies in humans have analyzed the clinical usage of mesenchymal stem cells in peripheral nerve reconstruction and revisions. The objective of this study was to evaluate the effects of undifferentiated adipose-derived stromal/stem cell injection during a last-chance surgery (neurolysis, nerve release) on a previously reconstructed nerve. Three patients (one female, two males; mean age 59 ± 4.5 years at the time of injury), who experienced failure of reconstructions of median and ulnar nerves, were included in this study. During the revision surgery, nerve fascicles were released, and adipose-derived stromal/stem cells were administered through microinjections along the fascicles and around the adjacent tissues after external neurolysis. During 36 months of follow-up, patients noticed gradual signs of sensory and in consequence functional recovery. No adverse effects were observed. Simultaneous nerve release with adipose-derived stromal/stem cells support is a promising method in patients who need secondary nerve release after nerve reconstruction. This method can constitute an alternative procedure in patients experiencing recovery failure and allow improvement in cases of limited nerve regeneration. The study protocol was approved by the Institutional Review Board (IRB) at the Centre of Postgraduate Medical Education (No. 62/PB/2016) on September 14, 2016.

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.

The Role of Fat Grafting in Alleviating Neuropathic Pain: A Critical Review of the Literature

Background

Neuropathic pain is one of the more severe types of chronic pain and presents a great challenge as response to medical therapy remains often unpredictable. With the opioid epidemic and the search for ways to avoid narcotics, physicians are seeking other modalities to treat neuropathic pain. In recent years, surgeons have explored various surgical avenues to improve outcomes. The aim of this review was to evaluate the current clinical evidence regarding the efficacy of fat grafting for the treatment of neuropathic pain.

Methods

A critical review was conducted to examine the current clinical evidence of fat grafting as a therapy for neuropathic pain caused by neuromas, peripheral neuralgia, migraine and headaches, neuropathic scar pain, and postmastectomy pain syndrome.

Results

The precise mechanism role of fat grafting in modulating neuropathic pain remains unclear, but it appears to reduce pain levels through the anti-inflammatory effects of adipose-derived stem cells and mechanical cushioning by fat.

Conclusions

Fat grafting is an emerging therapy for chronic neuropathic pain of various etiologies. Although promising results have been reported, sample size and level of evidence of current studies are low. The encouraging results, however, are worthy of further clinical and scientific study. The minimally invasive nature of fat grafting and favorable risk profile make this an attractive therapy for neuropathic pain.

Surgical interventions for the treatment of painful neuroma: a comparative meta-analysis

A consensus on the optimal treatment of painful neuromas does not exist. Our objective was to identify available data and to examine the role of surgical technique on outcomes following surgical management of painful neuromas. In accordance with the PRISMA guidelines, we performed a comprehensive literature search to identify studies measuring the efficacy of the surgical treatment of painful neuromas in the extremities (excluding Morton's neuroma and compression neuropathies). Surgical treatments were categorized as excision-only, excision and transposition, excision and cap, excision and repair, or neurolysis and coverage. Data on the proportion of patients with a meaningful reduction in pain were pooled and a random-effects meta-analysis was performed. The effects of confounding, study quality, and publication bias were examined with stratified, meta-regression, and bias analysis. Fifty-four articles met the inclusion criteria, many with multiple treatment groups. Outcomes reporting varied significantly and few studies controlled for confounding. Overall, surgical treatment of neuroma pain was effective in 77% of patients [95% confidence interval: 73-81]. No significant differences were seen between surgical techniques. Among studies with a mean pain duration greater than 24 months, or median number of operations greater than 2 prior to definitive neuroma pain surgery, excision and transposition or neurolysis and coverage were significantly more likely than other operative techniques to result in a meaningful reduction in pain (P < 0.05). Standardization in the reporting of surgical techniques, outcomes, and confounding factors is needed in future studies to enable providers to make comparisons across disparate techniques in the surgical treatment of neuroma pain.

Predictive value of a diagnostic block in focal nerve injury with neuropathic pain when surgery is considered

OBJECT

In patients with focal nerve injury and neuropathic pain cutting the nerve to obtain permanent pain reduction can be considered. Surgery is indicated only if a diagnostic nerve block provides temporary pain relief. We evaluated the predictive value of a block on the outcome of surgery.

METHODS

In total, three blocks were performed at two week intervals. Patients were blinded to injections containing lidocaine 1% and a placebo was included. Surgery was offered regardless of the effect of the blocks. Twenty-four patients received 72 blocks. Sixteen patients opted for surgery, 5 patients refrained from surgery, and in 3 the blocks provided permanent pain relief. The predictive ability of the block on the outcome of surgery was assessed by calculating the area under a Receiver Operating Characteristic curve (AUC).

RESULTS

The AUC of the first lidocaine block was 0.35 with a 95% confidence interval from 0.077 to 0.62. At 95% confidence (two-sided), the AUC is less than 0.62, and hence the predictive ability of the block was poor. The outcome of the second lidocaine block and saline block did not change the conclusion of the first block.

CONCLUSIONS

We conclude that the use of blocks to select patients for surgery should be critically appraised.

PERSPECTIVE

A pain relieving response to one open block is currently considered mandatory before patients with focal nerve injury and neuropathic pain are offered surgery. Blinded blocks including a placebo show that responses for selection should be carefully interpreted because they may not be as predictive as generally presumed.

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.

Outcome of Stromal Vascular Fraction-Enriched Fat Grafting Compared to Intramuscular Transposition in Painful End-Neuromas of Superficial Radial Nerve: Preliminary Results

Introduction

The management of painful end-neuromas of the superficial branch of the radial nerve (SBRN) remains challenging due to high levels of pain relapse. The novel technique of stromal vascular fraction (SVF)-enriched fat grafting showed continuous pain relief, although failed to prove statistically significant. Besides acting as a mechanical barrier, SVF-enriched fat grafting might also affect the cellular level. The aim of this study was to compare clinical outcomes of SVF to the widely popular intramuscular transposition technique.

Patients and methods

In this cohort study, 10 consecutive patients treated for painful end-neuromas of the SBRN between 2010 and 2013 were analyzed retrospectively. Microsurgical resection of end-neuromas was performed in all patients. Five patients were treated with subsequent intramuscular transposition into the brachioradialis muscle and five patients received SVF-enriched fat grafting. Five different pain modalities and various predictors were compared pre- and up to 36 months post-operatively.

Results

In the transposition group, sustained pain reduction was not observed after an initial significant reduction 2 months’ post-surgery, resulting in pain relapse at 36 months and comparable to the preoperative assessment. In the graft group, some degree of pain reduction was observed at 2 months after the surgery and proved to be constant in the long-term outcome, although not statistically significant compared to preoperative levels.

Conclusion

Both SVF-enriched fat grafting and intramuscular transposition failed to prove statistical significant pain reduction in treating symptomatic neuromas of peripheral nerves.

Stromal Vascular Fraction-enriched Fat Grafting for the Treatment of Symptomatic End-neuromata

The purpose of this study was to methodically illustrate and highlight the crucial steps of stromal vascular fraction (SVF)-enriched fat grafting as a novel treatment of symptomatic end-neuromata of peripheral sensory nerves, and in this study, specifically of the superficial branch of the radial nerve (SBRN). Despite a multitude of existing treatments, persistent postoperative pain and common pain relapse are still very common, independent of the procedure assessed. The neuroma is microsurgically excised accordingly to standardized protocol. Instead of the relocation of the regenerating nerve stump in neighboring anatomical structures, such as muscle or bone, a fat graft is applied perifocally and acts as a mechanical barrier. In order to reduce the fat resorption rate and boost the regenerative potential of the graft, the highly concentrated SVF is integrated in the grafting. The SVF is isolated from subcutaneous fat by enzymatic and mechanic separation of the lipoaspirate by a specific commercial isolation system. The SVF-enriched fat graft provides both a mechanical barrier and various biological effects at the cellular level, including improving angiogenesis, inflammation, and fibrosis. Both mechanical and biologic effects help to reduce the disorganized axonal outgrowth of the nerve stump during nerve regeneration and hence prevent the recurrence of painful end-neuromata.

Scar Tissue Causing Saphenous Nerve Entrapment: Percutaneous Scar Release and Fat Grafting

Painful neuropathies can be caused by nerve compression or neuromas. Nerve compressions can arise from scar adhesions causing painful posttraumatic entrapment of nerve branches via fibrosis. The classical treatment methods include neurolysis and nerve transposition. In this case, we present the treatment of recurrent scar entrapment of the saphenous nerve with percutaneous neurolysis and lipofilling in a patient who had previously undergone an open neurolysis procedure. Resolution of the condition without any complications was noted during the 2-month clinical follow-up. Percutaneous neurolysis and lipofilling are shown to be safe and reproducible methods for the treatment of neuropathic compressive scars.

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 novel treatment of SVF-enriched fat grafting for painful end-neuromas of superficial radial nerve

INTRODUCTION

None of the existing treatments in the management of painful end-neuromas of the superficial branch of the radial nerve (SBRN) has been proven superior due to high levels of pain relapse. Fat grafts enriched with the stromal vascular fraction (SVF) could act as a mechanic barrier with biological effects decreasing the resorption rate and boosting the graft's regenerative potential. This study describes the novel surgical treatment technique of SVF-enriched fat grafting.

PATIENTS AND METHODS

In this clinical study, five consecutive patients treated for painful end-neuromas of the SBRN between 2012 and 2013 were analyzed retrospectively. Microsurgical resection of end-neuromas followed by SVF-enriched fat grafting around the nerve stump was performed in all patients. Five different pain modalities and various predictors were compared pre- and up to 36 months postoperatively.

RESULTS

Pain reduction observed at 2 months after surgery was constant over time, though not statistically significant compared to preoperative levels. Spontaneous pain could be reduced from 1.6 ± 0.55 to 1.2 ± 1.1 (p = 0.414), spikes from 2.2 ± 1.3 to 1.4 ± 1.34 (p = 0.180), hyperaesthesia from 1.6 ± 1.14 to 1.2 ± 1.64 (p = 0.713), tap pain from 2.8 ± 0.45 to 1.8 ± 1.3 (p = 0.197) and motion pain from 2.8 ± 0.45 to 1.4 ± 1.34 (p = 0.066). An improvement in overall pain reduction could be observed from 2.2 ± 0.97 to 1.4 ± 1.26 3 years after the surgery (p = 0.104).

CONCLUSION

SVF-enriched fat grafting represents another alternative to numerous available treatments of painful end-neuromas of the SBRN. Our preliminary results could not show any significant difference in pain reduction following SVF-enriched fat grafting. Further larger trials are required in order to evaluate the therapeutic potential of SVF-enriched fat grafting.

Fat Grafting in Burn Scar Alleviates Neuropathic Pain via Anti-Inflammation Effect in Scar and Spinal Cord

Burn-induced neuropathic pain is complex, and fat grafting has reportedly improved neuropathic pain. However, the mechanism of fat grafting in improving neuropathic pain is unclear. Previous investigations have found that neuroinflammation causes neuropathic pain, and anti-inflammatory targeting may provide potential therapeutic opportunities in neuropathic pain. We hypothesized that fat grafting in burn scars improves the neuropathic pain through anti-inflammation. Burn-induced scar pain was confirmed using a mechanical response test 4 weeks after burn injuries, and autologous fat grafting in the scar area was performed simultaneously. After 4 weeks, the animals were sacrificed, and specimens were collected for the inflammation test, including COX-2, iNOS, and nNOS in the injured skin and spinal cord dorsal horns through immunohistochemistry and Western assays. Furthermore, pro-inflammatory cytokines (IL-1 β and TNF-α) in the spinal cord were collected. Double immunofluorescent staining images for measuring p-IκB, p-NFκB, p-JNK, and TUNEL as well as Western blots of AKT, Bax/Bcl-2 for the inflammatory process, and apoptosis were analyzed. Fat grafting significantly reduced COX2, nNOS, and iNOS in the skin and spinal cord dorsal horns, as well as IL-1β and TNF-α, compared with the burn group. Moreover, regarding the anti-inflammatory effect, the apoptosis cells in the spinal cord significantly decreased after the fat grafting in the burn injury group. Fat grafting was effective in treating burn-induced neuropathic pain through the alleviation of neuroinflammation and ameliorated spinal neuronal apoptosis.

Autologous fat grafting alleviates burn-induced neuropathic pain in rats

BACKGROUND

The management of neuropathic pain after burn injury is a critical clinical issue. Autologous fat grafting has been shown to alleviate neuropathic pain in certain cases, but has not been shown to alleviate the pain associated with burn-induced scars. The authors assessed the effectiveness of autologous fat grafting for the management of pain in burn-induced scars.

METHODS

One paw of the experimental rats received a third-degree burn using a heated metal block. Neuropathic pain in the affected paw was assessed based on behavioral responses to thermal and mechanical stimuli. A graft (0.4 ml of autologous fat or a sham graft) was administered by injection to the burn scar and sham-burned paw. The animals were killed 4 weeks after the fat graft treatments; Masson trichrome stain of hind-paw skin and expression of phosphorylated p38 and OX42 in the dorsal horns of the spinal cords were examined.

RESULT

The third-degree burns were completely healed at 4 weeks. Burn-induced scarring caused mechanical allodynia and increased the expression of phosphorylated p38 and OX42 in spinal cord dorsal horn microglial cells. Autologous fat grafting significantly alleviated mechanical allodynia (p < 0.05), and immunohistochemistry showed that the expression of phosphorylated p38 and OX42 was significantly lower in spinal cord dorsal horn microglial cells 4 weeks after fat grafting (p < 0.05).

CONCLUSIONS

Autologous fat grafting is used daily in clinical practice. It is an effective treatment for the relief of burn-induced mechanical allodynia in rats. Further investigation of the clinical use of autologous fat grafting in burn patients is warranted.

Treatment of painful median nerve neuromas with radial and ulnar artery perforator adipofascial flaps

PURPOSE

To review the outcomes of 8 patients with painful median nerve neuromas at the wrist treated with external neurolysis and covered with pedicled perforator adipofascial flaps.

METHODS

Between 2004 and 2010, we treated 8 patients, who had a mean age of 37 years, and who had posttraumatic painful median nerve neuromas at the level of the wrist but with retained median nerve function . All of them reported neuropathic pain and had a positive Tinel's sign over the site of the presumed neuroma. The surgical procedure included external neurolysis and coverage with an ulnar artery perforator adipofascial flap (4 patients) or with a radial artery perforator adipofascial flap (4 patients). Patients were reviewed after a mean follow-up of 41 months (range, 18-84 mo). Preoperative and postoperative pain was measured with a visual analog scale.

RESULTS

Pain improved from a preoperative mean value of 7.8 to a postoperative mean value of 3.6. There was complete resolution of pain in 5 patients, mild pain persisted in 2 patients, and 1 patient reported no improvement. No complications occurred at the donor site.

CONCLUSIONS

Vascularized soft tissue coverage of painful median nerve neuromas is an effective treatment. We do not believe that a free flap is of any particular advantage over a local pedicle flap which we suggest using to protect the median nerve.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.