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

Summary

The purpose of the study is to illustrate the technical procedure of stromal vascular fraction (SVF)-enriched fat grafting as a novel treatment of symptomatic end-neuromata. This technique provides advantages of both the mechanical barrier and the biological action at the cellular level by the processed and concentrated SVF.

Abstract

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.

Introduction

The management of symptomatic end-neuromata of the SBRN remains challenging with a multitude of existing surgical treatments. Principally, the neuroma is excised and the remaining nerve stump is relocated into neighboring structures such as muscles^1,2, bone³, or veins⁴. This is assumed to prevent the out-sprouting of the regenerating neural fascicles by mimicking the ambience of an end-organ. However, none of these techniques proved superior, as high rates of pain relapse and insufficient pain re....

Protocol

The protocol follows the guidelines of the University Hospital Zurich Human Research Ethics Committee.

1. Diagnoses of Neuromata and Patient Selection

1. Perform preoperative nerve blocks proximal to the neuroma in order to confirm the diagnoses. Assess the blocks in the middle third of the forearm and exclude potential triggers of the overlapping innervation areas of the SBRN, such as the lateral antebrachial cutaneous nerve (LACN), posterior interosseous nerve (PIN), and a dorsal branch of ulnar nerve¹⁰.
2. Perform surgery only in patients with considerable pain reduction (at least 5 points on the V....

Results

Data were analyzed using statistical software and presented as means ± standard deviations. The Kolmogorov-Smirnov test was applied to verify the nonparametric distribution of the study population and confirmed a negative empirical distribution. Based on the nonparametric nature of the study population, the Wilcoxon's test for related samples was employed to compare preoperative and postoperative outcomes. Statistical significance was regarded at p-values less than 0.05

Discussion

The purpose of the present study is to methodically illustrate the technical aspects of SVF-enriched fat grafting as a novel treatment for symptomatic end-neuromata.

Neuromata of the SBRN are associated with a surgical success rate of only 33%¹². Vaienti et al. presented a series of favorable results in early follow-up using perineural fat grafting (PFG) without adding the SVF in 8 patients with painful neuromata of the upper limb

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Cytori Celution System	Cytori		isolation system
Celase	Cytori		enyzme reagent
liposuction system
tumescent solution (500 ml Lactated Ringers, 20 ml of 1% lidocaine and 1 mg epinephrine)
14-gauge infiltrator
3 mm-collecting cannula (15, 26, 32 cm)
60 mL Tommey syringes
mosquito clamp
Toomey syringe stand
4 cannulas (fat injecting cannulas 1.5 mm, syringe NO.2, 90 mm)	Chalybs
10 mL syringes
connecting device for syringes
#11- and #15-blade scalpel
stevens scissors
pins pincette
bipolar electrocautery
suture material
adhesive dressing
binocular loupes magnifier glasses (2.5-3.5x)	Carl Zeiss
Statistical Package for Social Sciences, version 22	IBM