Stromal Vascular Fraction-Enriched Fat Grafting for the Management of Symptomatic Neuromas

Abstract

Source: Zimmermann, S., et.al. Stromal Vascular Fraction-enriched Fat Grafting for the Treatment of Symptomatic End-neuromata. J. Vis. Exp. (2017)

This video demonstrates the surgical procedure for neurolysis and stromal vascular fraction (SVF)-enriched fat grafting in the management of symptomatic neuroma. Neurolysis removes adhesion tissue to restore nerve gliding, while SVF-enriched fat grafting is applied around the nerve to create a protective barrier, support nerve healing, and enhance graft longevity.

Protocol

All procedures involving human participants have been performed in compliance with the institutional, national, and international guidelines for human welfare and have been reviewed by the local institutional review board.

1. Surgical Procedure

1. To approach the neuroma, make a skin incision over the previously diagnosed neuroma site in the distal third of the forearm.
2. Under the usage of surgical binocular loupes magnifier glasses (2.5 - 3.5X), continue to dissect the subcutaneous tissue and identify the involved nerve proximal to the neuroma.
   1. Subsequently, follow the nerve distally and identify the neuroma (based on visual inspection).
3. Once the full extension of the neuroma is clear, begin to excise the neuroma by a straight trans-neural scissor cut. If no neuroma is identified, only neurolysis of the nerve is performed.
4. Continue with the neurolysis of the remaining nerve stump until 3 cm proximal to the wrist.
   NOTE: The end of the nerve stump should be located in the middle of the principal incision.
5. Arrange two to four small puncture (stab) incisions (1 mm in diameter) with a scalpel through epidermal and dermal cutis around the principal approach.
6. Place two to four blunt cannulas (16-gauge, length 9 cm) via the stab incisions perineural to the stump.
   NOTE: The tip of the cannulas should be directed towards the nerve stump.
7. Secure the cannulas in place by adhesive dressing.
8. Place the stitches around the cannulas and leave the suture material in situ without securing the node.
9. Suture the main incision tightly in order to prevent the outflow of grafting.
   NOTE: Ensure that cannulas remain in situ.

2. Application of the SVF-enriched Fat Graft

1. Aspirate 5 mL of SVF in a 10-mL communicating syringe.
2. In the same manner, aspirate 2 mL of the sedimented lipid fraction in the opposing 10-mL syringe.
3. Mix the 5 mL of SVF with the 2 mL of the sedimented lipid fraction by alternating pulling back the plunger of one syringe and pulling down the plunger of the communicating, opposing syringe until sufficient mixing is obtained.
4. Divide the SVF-enriched fat graft equally in two to four 10 mL syringes.
5. Distribute the prepared SVF-enriched fat graft one after the other equally around the nerve stump by connecting the syringes to the blunt cannulas.
   NOTE: Before applying the graft, ensure that the cannulas are secured in the correct position and be careful not to dislocate the cannulas while applying the fat graft.
6. Remove the cannulas carefully.
7. Then, tape the small puncture incisions with steri-strips.
8. Immobilize the hand by applying a splint in the intrinsic plus position (metacarpophalangeal (MCP) joints flexed at 60 - 70°, the interphalangeal (IP) joints fully extended, thumb in the fist projection, wrist in dorsal flexion of 25°). If only neurolysis of the nerve is performed, no splint is needed and arm and wrist are bandaged for 10 days.

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
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