Socket: Dermis Fat Graft

What is a Dermis fat graft?

A dermis fat implant (dermofat graft, DFG) is an autologous transplant consisting of the de-epithelialized epidermis with its adjacent subcutaneous fat tissue. It can be used as an alternative orbital implant to alloplastic implants. Currently, it is the only autologous transplant used for this purpose in ophthalmic plastic and reconstructive surgery.

What are the indications?

One of the main indications for a Dermis fat grafts is congenital anophthalmia. The procedure is also indicated for complications of secondary anophthalmia following the occurrence of trauma, corneal ulcer, malignancy or intraocular tumour with or without radiotherapy, glaucoma, endophthalmitis, painful blind eye, and others. In a retrospective review of 41 patients by Aryasit and Preechawai, the 3 major indications for secondary DFG included:

• Exposure of orbital implant (32%)
• Extrusion of an orbital implant (27%)
• Volume insufficiency with shallow fornix (24%).

Others have also indicated good success using DFG for:

• Primary implantation
• Severely contracted socket

What does the surgery involve?

• An ellipsoid approximately 20 mm in diameter is placed in the lower abdominal quadrant or flank, these areas are less prone to be tender, and are non-weight bearing. Some surgeons prefer harvesting the DFG from the buttocks or lateral portion of the thigh. The ultimate diameter of the harvested graft most does not exceed 25mm.
• The surgical site is locally anaesthetized with lidocaine 2% with epinephrine 1:100,000.

• A #15 blade is then used to make an incision along the marking through the epidermis.
• The #15 blade is then used to excise the epidermis from the underlying dermis. The epidermis is best removed with the dermal tissue in situ. The epidermis is excised so that keratin is not produced in the socket.
• Holding the #15 blade perpendicular to the dermal face, an incision is made along with the dermis to the underlying fat following the ellipse. Holding the blade perpendicularly is important in harvesting an adequate size composite-graft that is slightly wider at the base away from the dermal side. Beveling the blade will yield a conical-shaped graft with inadequate fatty tissue.
• Steven scissors or Metzenbaum scissors are then used to bevel out to excise as much fat as possible.
• It is important to harvest more fat than what you think you will need since you will lose approximately 50% of your fat volume as things heal.
• The graft can then be placed in moist saline gauze or in the physiologic saline solution until needed.
• The incision is then closed with deep interrupted 4-0 monocryl sutures. Vicryl sutures could also be used if preferred.
• The skin can then be closed with a 5-0 or 4-0 prolene suture.
• The edges of the skin should be everted. In this case, a running horizontal mattress suture is placed.
• Antibiotic ointment is then be placed over the incision, a Telfa dressing and a pressure bandage are applied for a week.
• The graft is then transferred to the anophthalmic socket, and each of the muscles that have been tagged with the double-armed 5-0 vicryl sutures is sutured to the edge of the dermis.  It should be very difficult to get all of the fat into the socket. 
• The conjunctival edges are then sutured to the edge of the dermis with 6-0 vicryl suture, in a running or interrupted fashion. It is important to make sure that the edges of the conjunctiva are not buried or an inclusion cyst may later develop.  In the following 4 weeks approximately, the dermis should become epithelialized by the migration of cells across the graft from the conjunctival edges. 
• At the conclusion of the case, a large conformer is placed.  A temporary suture tarsorrhaphy can often be placed.  The eye is then patched for a week. 

Aftercare following the surgery

Regarding the post-operative care for the surgical site from where the graft was obtained, tends to heal in the same fashion as other wounds approximated by primary intention. Some surgeons place a patient who undergoes autogenous tissue grafts in oral cephalosporins for 5-7 days. Graft site hematomas have been reported and should be dealt in a conservative manner. If the surgical site is under tension, it would be advisable to release the sutures and apply a compression bandage to the site. Closure can be reattempted after the swelling has diminished. 

After appropriate layered closure has been achieved at the socket, after implantation of the DFG, a conformer should to place, as well as an antibiotic ointment. The conformer will prevent extrusion of the graft, as well as proper maintenance of the fornices for a future ocular prosthesis to be fitted, usually by 6 weeks.

What are the complications?

The complications of dermis fat graft may include:

At the site from which the graft is harvested:

• Hematoma

• Infection

• Graft-wound dehiscence

In the socket where the DFG is implanted:

• Conjunctival cysts

• Granulomas

• Graft ulcers

• Pyogenic granuloma

• Socket keratinization

• Cilia retention at the recipient site

• Fat atrophy and volume loss --this occurs more commonly than fat hypertrophy and may have many factors

• Excessive dermis-fat growth-- this has been reported in dermis fat grafts placed in young children

• Graft failure 

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