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HEALING OF DERMIS, FAT & FASCIA
DIRK LAZARUS
7 FEBRUARY 1997
INTRODUCTION
Uses:
1) soft tissue augmentation
2) coverage of vital structures
3) elimination of dead space
4) reconstruction of ligamentous or fascial defects

Autologous tissue better and more reliable than prosthetic.
DERMIS TRANSPLANTATION
 Transfer of the deep layer of the papillary dermis and the whole reticular dermis.
 If subcutaneous fat included, = dermal-fat graft.
 The epidermis is removed by de-epithelialised or as a SSG.
 Historically has been used to replace fascia for hernia repair, as a substitute for
tendons, for ligament repair, for dural patches, for internal fixation of #s, for
arthroplasty, to repair stenotic bronchial tubes, for diaphragmatic repair and for
correction of soft tissue defects.
 For augmenting soft tissue defects, found to be better than if fat or fascia used
alone.
Fate of Dermal Grafts
 Routine survival of a FTSG depends on the viability of the dermis layer.
 Early survival is by plasmic imbibition and inosculation.
 Removal of the epidermis ensures early vascularisation. If the epidermis is not
removed and transplanted, it dies.
 Sebaceous glands and hair follicles disappear at 2 wks and 2 mths respectively. In
the interim, they form microscopic epidermoid cysts which accumulate keratinised
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epithelial debris within the lumen of the cyst, the cyst thus swells and becomes
necrotic.
 Sweat glands survive transfer the longest and continue to function. The sweat that
is secreted is absorbed internally.
 Mesodermal metaplasia of the dermis occurs in response to the functional demands
of the recipient site: tension transforms the dermis into a tendon-like structure;
compression into a cartilage-like structure.
Surgical Technique
 Uses: lip and cheek augmentation, correction of saddle nose deformity.
 Prerequisites for success: inconspicuous donor site; favourable recipient bed (no
scar
or
infection,
well
vascularised);
meticulous
haemostasis;
adequate
immobilisation.
 Donor sites: groin, lower abd, gluteal fold, lateral gluteal, IMC, pre-existing scar.
 Graft harvested as an ellipse and closed primarily. Epidermis removed. De-fatted.
Graft tailored to the defect. To allow for contraction, the graft should be 25%
larger than required.
Bevel the edges.
For small defects, the grafts can be
sutured in place using a threadable needle.
Cx: haematoma, infection, cyst
formation, resorption.
FAT TRANSPLANTATION
 Fat can be transferred as free graft, free graft with dermis, microvascular transfer or
by fat injection following SAL.

First used at the end of the 1800s as an omental transposition between the
liver and the diaphragm (Van der Meulen, 1889) and as free fat grafts to fill a
soft tissue depression (Neuber, 1893).
Neuber recommended that free fat
grafts should not exceed the size of an almond.
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
Illouz reported the transfer of liposuction aspirate fat in 1984. In 1986,
Ellenbogen reported the use of free pearl fat autografts in a variety of atrophic
and posttraumatic facial deficits.
 Historical uses have been broad and varied and encompassed almost every aspect
of surgery:
1) For the face: to fill depressions secondary to facial and hemifacial atrophy, for
filling of depressed scars, for filling of wrinkles, lines, folds and creases, for acne,
for post-traumatic defects, for chin and lip augmentation, etc. Ellenbogen (1986)
used autografts or “pearls” 4-6 mm in diameter and to maximise take advocated
numerous adjuvent measures: exogenous vit E, treatment of the implant bed with
insulin, small grafts, atraumatic, aseptic technique.
2) For breast enlargement: Through history multiple attempts have been made at
breast augmentation by free fat grafts, dermal fat grafts, pedicled fat flaps, free
fat flaps and fat injections.
3) Other uses of free fat autotransplantation: Orthopods have used fat autografts to
fill both septic and aseptic bony defects and for joint ankylosis. Neurosurgeons
for defects of skull, dura and brain. Autografts have been used to surround
nerves following neurolysis.
pulmonary defects.
Thoracic surgeons for chest wall, pleural and
Other uses include filling the orbital cavity after eye
enucleation, to fill or occlude the sinuses or their ostia, for cosmetic ear defects,
to control parenchymal (kidney) haemorrhage, for peritoneal adhesions, for abd
wall defects, for GU fistulae, following tenolysis, for CP, to close oro-nasal and
septal defects and for subdermal augmentation.
 This wide and varied application of free fat autotransplantation in surgery indicates
the usefulness of the material for small defects under ideal conditions. In other
situations, free fat autografts have given poor and unpredictable results (James
May).
Fate of Transplanted Fat
 According to McC, 2 schools of thought:
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1) Host cell replacement theory: Transplanted fat cells do not survive and host
histiocytes phagocytose the lipid and are transformed into new adipocytes.
2) Cell survival theory: Some fat cells do survive. Histiocytes act as scavengers of
lipid and do not replace graft adipose tissue.
 Cell survival theory favoured (grafts that are handled gently have a better outcome).
The preadipocyte is believed to be the important cell in fat transplants. These
young mesenchymal cells have a potential to differentiate into mature adipocytes and
mature adipocytes seem to have the ability to de-differentiate into preadipocytes.
 In the first 4 days following fat transplantation, there is an extensive host cellular
infiltration as part of an acute inflammatory response (polys, plasma cells, lymphos
and eosinos).
Survival is as for other grafts and depends on initial plasmic
imbibition (first 72hours) and inosculation.
 Peer (1950) noted that at 1 year, 50% of the fat graft is lost and postulated that
much of the graft is converted to fibrous tissue.
 He noted that a fibrotic capsule usually surrounds the graft.
 Grafts from lean individuals retain more bulk than grafts from obese patients.
 Grafts in children are generally smaller with smaller fat cells and so the grafts tend
to retain more bulk.
 Subfascial or intramuscular injection gives best viability
Technique (Sidney Coleman 2002)
 Fat tissue consists of fat cells, which have thin cell membranes enmeshed in a
fibrous network. Without the supporting fibers, the cells tend to collapse.
 Harvesting fat while maintaining as much supporting structure as possible
preserves structural integrity of the tissue and helps the tissue retain bulk in the
transplanted site.
 The most important principle in the surgical management is the atraumatic
transfer of fat.
 3 Parts
1. Harvesting
2. Refinement/Processing
3. Placement
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Harvesting cannulas have blunt tips in the shape of a bucket handle. The proximal
end is shaped to fit securely into a 10-cc Luer-Lok syringe
 Harvesting
1. abdomen and medial thigh donor sites
2. infiltrate superwet solution using a blunt infiltrator
3. Around the distal openings, sharp edges are minimized to encourage
harvesting small parcels rather than long strips of tissue.
4. Gently pulling back on the plunger of a 10-cc syringe provides a light
negative pressure while the cannula is advanced and retracted through
the harvest site. Devices that lock the plunger of syringes into place and
high-pressure vacuum suction systems used for liposuction can create
higher negative pressures, and they may damage the fragile fatty tissue
during harvesting
5. Increasing the power suction from -0.5 atm to -0.95 atm has been
experimentally demonstrated to result in the breakage and vaporization of
fat cells, destroying their ability to be successfully transplanted.
 Refinement
1. Seal Luer-Lok, remove plunger and place into centrifuge
2. Centrifuging at about 3000 rpm for 3 minutes separates the harvested
material into three layer
3. The upper level, or less dense level, is composed primarily of oil from
ruptured fat cells. The middle portion is composed predominantly of
parcels of tissue. The lowest level is the densest layer and is composed
primarily of blood, water, and lidocaine
4. The oil is decanted via the plunger end. The Luer-Lok cap is then
removed and the aqueous components are allowed to drain. A Cottonoid
surgical strip is inserted into the barrel of the syringe touching the
harvested fat for at least 4 minutes to wick off any remaining oil.
5. choice of fluid for fat suspension is controversial. Most commonly, normal
saline or lactated Ringer solution is used. Serum free culture medium is
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also available, although it is more expensive. Some groups advocate
additives such as heparin, insulin, vitamin E, and nonsteroidal anabolic
hormones. The contribution of lidocaine is also debatable.
 Placement
1. Fat desiccates easily, and histologic studies have demonstrated
cytoplasmic lysis of up to 50 percent of the cells exposed to air for 15
minutes. A brief exposure to ambient air is inevitable during these stages
of harvesting and refinement, but exposure to air should be minimized.
2. Transfer fat from 10ml into 1ml syringe
3. Incisions 1 to 2 mm in length are placed in the direction of the wrinkle
lines
4. Blunt 17G infiltration cannula is completely capped on the tip with a lip
that extends 180 degrees over a solitary distal aperture(below)
5. Studies have demonstrated that as little as 40 percent of grafted fatty
tissue is viable 1 mm from the edge of the graft at 60 days. In other
words, 60 percent of the grafted fat cells that are more than 1 mm from a
source of nutrition and respiration will die. In a parcel isolated from other
grafted parcels, decreasing the diameter of the grafted fatty tissue
parcels makes the most central cells closer to the outside of the parcel
and to a blood supply.
6. A large number of passes are made through each incision site to develop
a radiating pattern. Placement of fat from multiple directions creates a
weaving pattern of placement.
7. Separating the parcels of fat by placing them in many passes allows the
parcels to touch more of the surrounding host tissue and thereby
maximizes the surface area of contact of fatty tissue with the surrounding
host tissues. This creates a larger surface area not only for diffusion
respiration but also for anchoring of the fat.
8. <0.1ml injected with each pass. Avoid overfilling the track. Overfilling can
adversely affect graft survival and graft location
9. Fat is grafted from the deep layer to the superficial layer.
10. Slight overcorrection is important because some absorption of the liquid
carrier occurs. Some groups recommend a 30% overcorrection.
11. With lip augmentation, grafting near the mucosa increases the amount of
vermilion show. Grafting near the white roll tightens perioral rhytides.
Gatti describes injection of 3 mL into the upper lip and 4 mL into the lower
lip, although much larger amounts have been reported.
12. Serial injection may be performed at 3-month intervals. Generally, 3
procedures should be anticipated. Even distribution of the injection is
crucial. Excess bulk in a particular area may isolate the fat in the central
region from the new blood supply.
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The Role of the Pre-adipocyte
 Postulated as follows:
 The graft of mature adipose tissue with its connective tissue stroma, when
implanted, goes through an initial period of ischaemia and inadequate nutrition. This
could cause many of the mature fat cells to follow one of 2 courses:
a) either they undergo necrosis, or
b) they de-differentiate to preadipocytes.
 When the blood supply is restored, and the supply of oxygen and nutrient is reestablished in the graft, the pool of preadipocytes could differentiate into mature
adipose tissue, albeit of lesser volume (d/t those that were initially lost to
necrosis?).
 The preadipocyte is a fibroblast-like cell of mesenchymal origin that seems to have
a greater resistance to trauma than mature adipocytes laden with lipid.
 In the future, preadipocyte may be cultured and then injected back into the patient.
Dermal-fat Grafts
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 Has number of advantages:
1) Dermis makes the graft stronger and easier to handle
2) Dermis makes the graft more stable allowing better take
3) Less loss of bulk and fibrous replacement had been reported.
 Others have found that the presence of the dermis does not affect fibrous
replacement. Diffusion initially nourishes the graft to a depth of only 1 mm. A 33%
reduction in graft volume has been noted at 8 weeks. The dermis does however
improve re-vascularisation.
Clinical Application
 Groin and gluteal area are the prime donor sites.
 The graft must be handled gently during de-epithelialised and transfer. It must be
slightly oversized.
It must be well secured.
Infection must be absent and
haemostasis meticulous.
 Peer (1950) noted that at 1 year, 50% of the graft is lost.
 Over-correction is thus advocated, but should not exceed 20% otherwise excess
deformity is created.
 Grafts of fat only are usually restricted to small grafts used, for example, to
obliterate sinuses.
 Dermal fat grafts can be larger and used for defects of hemifacial atrophy, etc.
 Vascularised transfers: omentum; TRAM.
 Fat injection used in facial rejuvenation: correction of wrinkles, N-L folds, etc.
FASCIA TRANSPLANTATION
 Uses: repair of hernias, as slings to correct facial palsy, to secure the tongue in
Pierre Robin, as an interposition in correction of TMJ ankylosis, to lengthen the
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tendons of transferred muscles, for repair of urethral fistulae, for closure of nasal
septum, for coverage of exposed implants, etc.
 Donor areas: fascia lata, temporalis.
 Harvesting fascia lata: 10-15 mm strip can be harvested without causing significant
morbidity. Wider strips may allow muscle herniation through the defect. A fascial
stripper is useful.
 Vascularised fascial transfer: temporo-parietal free or pedicled flap useful for ear
reconstruction, avulsed scalp re-surfacing, reconstitution of soft tissues, hand
coverage.
REFERENCES
McC (Chapter 15)
PRS 83(2), Feb 1989