TISSUE EXPANSION PRINCIPLE AND APPLICATION

1. TISSUE EXPANSION PRINCIPLE
AND APPLICATION
Dr. Amit Kumar Choudhary
SR Plastic and Reconstructive Surgery
RIMS,Imphal
Moderator-Dr. AK. Ibohal Singh

2. HISTORY OF TISSUE EXPANSION
• Neumann induced soft tissue growth with a subcutaneously implanted balloon in an attempt to
reconstruct an external ear deformity.
• Radovan and Austad simultaneously evolved the concept of purposeful soft tissue expansion with
use of an implanted silicone balloon.
Radovan's device contained a self-sealing valve through which saline was periodically injected to
increase size of the prosthesis.
• Austad's prosthesis was devised as a self-inflating device using osmotic gradients driven by salt
placed within the expander.

3. BIOLOGY OF TISSUE
EXPANSION

4. Epidermis
• Early after placement of the prosthesis, significant thickening of the epidermis is evident. Within 4 to
6 weeks, epidermal thickness generally returns to initial levels, but some increase in thickness
persists for many months.
• Hair follicles and accessory skin structures are compressed but no evidence of degeneration.
• Animal studies demonstrate that there may be an increase in number of hairs and density
proportional with expansion.
• Melanocytic activity is increased during expansion but returns to normal within several months after
completion of reconstruction

6. Dermis
• The dermis decreases rapidly in thickness over the entire implant during expansion.
• Dermal thinning persists at least 36 weeks after expansion is completed . A dense fibrous capsule is
formed around the implant, which becomes less cellular over time.
• The capsule is thickest at 2 months of expansion. Progressive collagenization with well-organized
bundles develops during 3 months.
• Dystrophic calcification may occur when a hematoma resolves or when the prosthesis is repeatedly
traumatized.
• Expanded tissue demonstrates a quantitative increase in collagen content of the dermis. After
expansion, the relative proportions of type I and type III collagen are not significantly changed in
the dermalepidermal or subcutaneous-capsular interface.
• Mitotic activity in the capsule fibroblast is maximum about 96 hours after expansion.
• The application of a constant pressure beyond 96 hours results in progressive decrease in mitotic
activity

7. Muscle
• Muscle atrophies significantly during the process of
expansion, whether the prosthesis is placed above or below a
specific muscle .
• The effects on human muscle after expansion have demonstrated
occasional histologic ulceration.
• Focal muscle fiber degeneration with glycogen deposits and mild
interstitial fibrosis have been noted. Some muscle fibers show
disorganization of the myofibrils in the sarcomeres.
• Expansion of skeletal muscle is not a stretching process but rather a
growth of the muscle cell accompanied by an increase in the
number of sarcomeres per fiber.

9. Cranial Bone
• There is a decrease in bone thickness and volume in cranial bone beneath the expander, but bone
density is unaffected.
• An increase in bone volume and thickness occurs predominantly at the periphery of the expander.
• Osteoplastic bone resorption occurs beneath expanders, and a periosteal inflammatory reaction is
seen at the periphery of the expander.
• Cranial bone appears to be significantly more affected than long bone is. Long bone remodeling
begins within 5 days after removal of the expander, and the long bone is completely normal within
2 months.

10. Vascularity of Expanded Tissue
• It has been clinically and histologically demonstrated that a large number of new vessels are
formed adjacent to the capsule.
• The content of collagen fibers in existing vessels initially decreases after expansion.
• Elastic fibers in existing blood vessels initially increase, probably as a response to mechanical stress.
• Angiogenesis probably occurs secondary to ischemia of the expanded tissues.
• Cells expressing vascular growth factor is significantly increase.

11. SURVIVAL
• Flaps elevated in expanded tissue have
significantly greater survival areas compared
with acutely raised and delayed flaps.

12. Ultrastructure of Expanded Tissue
• The epidermis demonstrates a reduction of intercellular distance and a significant
decrease in the undulation of the basal lamina .
• The dermis displays large, compact bundles of collagen fibers oriented in parallel
fashion over the implant surface.
• Active fibroblasts are found in the expanded dermis.
• Myofibroblasts develop in the deep dermis adjacent to the capsule.
• Skeletal muscle demonstrates pressure atrophy with increased mitochondria and
abnormal rearrangement of sarcomeres.

13. Molecular Basis for Tissue Expansion
• Intracellular tension and cell structure are maintained by a system of microfilaments within
the cytoplasm.
• These microfilaments act to transduce signals to adjacent cells and play a critical role in
initiating transduction cascades within the cell.
• Protein kinase C plays a pivotal role in signal transduction.
• Mechanical strain on cell walls activates inositol phosphatase, phospholipase A2,
phospholipase D, and other messengers.

16. • Activation of these components results in protein kinase C activation. Protein kinase C is
associated with nuclear proteins, intracellular signals can be transmitted to the nucleus.
• Many growth factors, including platelet-derived growth factor and angiotensin II, play a role
in strain induced cell growth.
• Platelet-derived growth factor has a effect of stimulating cutaneous cell proliferation.
• Transforming growth factor-β production has also been demonstrated in stretch in vitro
models and has been implicated in extracellular matrix products.

17. The Source of Increased Tissue from Expansion
• The increase in skin surface area over the expander includes normal skin brought
in from adjacent areas as well as new skin generated by increased mitosis.
• Increased mitotic activity in the epidermis directly overlying the expansion.Serial
inflations of the prosthesis result in serial increases in tritiated thymidine uptake.
• With deflation of the implant, a significant decrease in the rate of the epidermal
mitosis below normal baseline occurs.

18. IMPLANT TYPES

19. Radovan's expander
• Radovan's expander consisted of a silicone prosthesis with two valves, each connected to the
main reservoir by silicone tubing.
• One valve was used for injection; the other was used as a means to withdraw fluid.
Technologic improvements resulted in a single valve for both purposes.
• The filling reservoir may be incorporated directly into the prosthesis. Such devices have the
advantage of avoiding the remote port.
• The valve in the integrated prosthesis can be difficult to palpate.
• Breast reconstruction with these prostheses has become popular..

20. Expanders with distal ports
• Remote filling ports.
• Advantage of minimizing the risk of implant
puncture during inflation.
• The distal , self-sealing injection port and inflation
reservoir are connected to the prosthesis by a
length of tubing.
• This allows the injection port to be placed away
from the expander pocket.
• It is also possible to move the inflation port of a
distant reservoir to the exterior of the body; this
location facilitates inflation, particularly when the
expansion is accomplished by family member.

21. DISTAL PORT

22. Expanders with integrated ports
• The inflation reservoir may be incorporated directly in the prosthesis.
• Advantage of avoiding the remote port and its associated mechanical problems.
• Risk of inadvertent perforation of the prosthesis during inflation is higher .
• Magnetic and ultrasonic devices can be useful when the valve is difficult to locate and
metal finding devices have been designed.
• Expander prostheses with integrated valves are particularly popular for breast
reconstruction where adequate soft tissue and pocket can accommodate the added
projection of the injection port.

23. Self-inflating expanders
• Self-inflating expanders have become available largely through
Europe.
• These contain osmotic hydrocolloids that cause migration of
extracellular water through the silicone membrane of the device.
• The first such expander was devised by Dr. Austad and was used
experimentally.
• It was not approved by the Food and Drug Administration

24. BASIC PRINCIPLES
• Tissue expansion is a protracted procedure that may involve temporary, but very
obvious, cosmetic deformity.
• Emotionally stable patients of all ages tolerate tissue expansion well.
Noncompliant or mentally impaired patients are poor candidates.
• Smokers have a higher risk of complications.
• Tissue expansion is generally best performed as a secondary reconstructive
procedure rather than in the acute trauma period.
• Expansion can be performed adjacent to an area of an open wound before
definitive closure, but such a procedure carries the risks of infection, extrusion,
and less than-optimal results.
• Tissue expansion is best suited to those patients who require definitive, optimal
coverage ,when time is not of the essence.

25. Incision planning and implant
selection
• The proposed type of flap
– advancement
- rotation
- Interpolation
The simpler the flap, the less the potential for complication.
• planning
(1) incisions are incorporated into tissue that will become one margin of the flap
(2) aesthetic units are reconstructed
(3) scars are in minimally conspicuous locations
(4) tension on suture lines is reduced.

26. • Incisions should be planned to minimize tension on the suture line and risk of
extrusion.
• Tension from the initial inflation on the suture line will be greater when incisions
are parallel to the direction of expansion than when they are perpendicular to it.
• Undermining of the prosthesis should be sufficient enough that the prosthesis can
be easily accommodated and the wound can be closed in multiple layers.
• The inflation valve and tubing should be maintained at a site away from the
incision.

27. The size of the implant
• The size of the implant selected should closely relate to the size and shape of the donor
surface.
• An implant equal to or slightly smaller than the donor area is selected.
• In general, the use of multiple small expanders is better than the use of one large expander.
Inflation of multiple prostheses proceeds more rapidly and complications are fewer.
• Multiple expanders also allow the surgeon to vary the plan for reconstruction after expansion
• An integrated valve and a distal inflation port should be considered on a case-by-case basis.

28. Implant and distal port positioning
• If a remote filling port and reservoir is chosen,it must be
placed superficially in subcutaneous tissue,where even an
extremely small port is easily palpable under stable skin.
• To minimize discomfort, it is occasionally possible to
position a filling port in an area that is relatively less sensitive.
• The port should be placed in a location that will not be
subjected to pressure .
• Bony prominences are avoided

29. Implant inflation strategy and
technique
• Implants should be partially inflated immediately after wound closure. This allows closure of
“dead space” to minimize seroma and hematoma formation.
• It also smoothes out the implant wall to minimize risk of fold extrusion.
• Enough saline is placed to fill the entire dissection space without placing undue tension on
the suture line.
• Serial inflation usually starts 1–2 weeks after initial placement.
• Inflation reservoirs seal best when a 23-gauge or smaller needle is used. A 23-gauge butterfly

30. • Frequent small-volume inflations are better tolerated and are physiologically more suited to the
development of adequate overlying tissue than are large infrequent Inflations
• inflations proceed until the patient experiences discomfort or blanching of the overlying skin.
• Devices such as pressure transducers and oxygen tension monitors are available to help determine
proper inflation.
• An objective inspection of the patient’s response is usually a reliable indicator of appropriate
inflation.
• Serial inflations proceed until an adequate amount of soft tissue has been generated to accomplish
the specific surgical goal.

31. Tissue expansion in
special cases

32. Burns
• Reconstruction should be carried out after all burns have and scars have
matured.
• Planning is particularly important in these cases so that a minimum
number of suture lines is produced and that these suture lines do not
cross aesthetic units.
• Significant late distortion and contracture may result in excessive scars
placed in burned tissue, particularly in the facial area

33. Tissue expansion in children
• Skin and soft tissue are always thinner in children than in adults. These tissues are
probably better vascularized but less resistant to trauma.
• Tissue expansion has a higher complication rate in children than in adults.
• Major complication risk – particularly extrusion – is more common at the second,
third, and fourth serial expansion. This is particularly true in the head and neck
(with the exception of the scalp).
• Small-volume inflation at frequent intervals is especially useful in children because

34. Expansion of myocutaneous, fascial,
and free flaps
• Myocutaneous flaps are the standard of care for the treatment of large defects, particularly when
bone and vital structures are involved.
• The territories of standard flaps are well described. These territories can be considerably enlarged
by placing an expander beneath the standard myocutaneous flap, and an extremely large flap can
be developed over a short period.
• Expansion increases the vascularity of the flap and allows a large,adjacent random area to be
carried with the original flap.
. The vascular pedicle of such flaps remains intact and may in fact be elongated, thus allowing flaps to
be transferred farther.

35. • Myocutaneous flaps such as the latissimus dorsi
and pectoralis can be expanded to almost double
their surface area, allowing coverage of almost
any defect on the abdomen or thorax.
• Expanders of up to 1000 Ml can be placed
beneath such flaps and rapidly expanded.

36. Expanded full-thickness skin grafts
• Donor defect is usually created by harvesting full-thickness grafts.
• The placement of a large tissue expander beneath the donor site can result in a
large full-thickness graft that is particularly useful in resurfacing large areas .
• The best color matches are generated when the full thickness graft is expanded
and harvested as close as possible to the recipient site.
• The periorbital area and the area around the mouth are particularly well suited to
reconstruction with expanded full-thickness grafts harvested from the
supraclavicular area.
• Expanded full-thickness grafts are very helpful in reconstructing defects of the
forehead . A single full-thickness graft can be harvested from the supraclavicular
area or from under the breast fold.

37. • The full-thickness graft is approximately 10–15% larger than the recipient
area.
• Expanded full-thickness skin grafts require more immobilization than split
thickness.
• A bolster dressing or, ideally, a VAC sponge dressing is required. The graft
is sutured in place and a VAC sponge placed over the graft; 125 mmHg of
negative pressure is maintained for 4 days.

38. APPLICATION OF TISSUE
EXPANSION

39. HEAD AND NECK
• The skin of the face can be subdivided into five tissue specific areas:
1. The scalp
2. The forehead is a continuation of the scalp, but it is distinguished from the scalp by its thick
skin, large number of sebaceous glands, and lack of hair.
3. The nose is embryologically related to the forehead, so it closely mimics the forehead in color,
texture, and sebaceous gland content.
4. The lateral cheek areas, neck, and upper lip have fewer sebaceous glands; the skin is thinner, and
the hair-bearing pattern is significantly different in quality and quantity from that on the
remainder of the body.
5. The skin of the periorbital areas is extremely thin and pliable, containing a minimal number of
sebaceous glands

40. Scalp
• Tissue expansion is the ideal procedure for the
reconstruction of scalp defects.
• Expansion of the scalp is well tolerated and is the only
procedure that allows development of normal hair-bearing
tissue to cover the areas of alopecia.
• The amount of scar and deformity generated is considerably
less than other procedures such as serial reduction and
complex multiflap procedures.

41. • The darker the hair, the more visible the thinning is.
• Individuals who have large defects and require extreme
expansion may achieve better results by lightening the
hair with dyes.
Advancement or rotation flaps achieve the best
results, particularly when the anterior hairline is
reconstructed.

44. Forehead
• The forehead is anatomically and histologically identical to the scalp except for its different
numbers of sebaceous glands and hair-bearing follicles.
• Reduction or increase of the surface area of the forehead by 20–25% is not usually readily
apparent after appropriate hair styling
• .
By expanding the scalp in conjunction with expanding the forehead, better symmetric brow
positioning is achieved while maintaining the normal hairline.
Expansion of the forehead is useful in many craniofacial anomalies with low hairlines.
Expansion of the remaining forehead is accomplished and moved into a cephalad direction.
The intervening hair-bearing scalp is excised

45. Lateral face and neck
• The type of skin on the lateral facial
areas and neck is essentially the same.
• A large Mustardé expanded rotation
flap can be developed on the neck for
use in facial reconstruction.
• In children, there is a higher risk of
extrusion problems in the expansion of
this area of the face .
• Adults, such reconstruction can be
accomplished with relative ease. The
flap is based inferiorly and medially.

47. Nose
• Reconstruction of major defects of the nose, including total nose reconstruction,
may be facilitated by pre expanding the forehead skin.
• when total nose reconstruction is performed, expansion of the entire forehead
with a 400–600-mL prosthesis generates an adequate number of large, well-
vascularized flaps to accomplish both total nose reconstruction and closure of the
donor site.
• Because the color and texture of the forehead are ideally suited to reconstruction
of the nose, this procedure makes reconstruction of any nasal defect possible.

48. • A cranial bone or rib graft is
taken to reconstruct the
dorsum of the nose. This is
either secured to the
remaining nasal bone or
attached by a plate to the
skull.
• The nasal cartilage is
reconstructed bilaterally
with cartilage from the
conchal bowl.

49. Ear
• Most cases of microtia and traumatic ear deformities can be
reconstructed without expansion.
• Expansion is helpful when skin and soft tissue are insufficient for
reconstruction.
• As with all ear reconstructions, a child should be approximately 7
years of age before reconstruction is begun.

50. Periorbital area with expanded
full-thickness grafts
• The periorbital area contains skin that is soft and pliable.
• Little tissue in the periorbital area can be expanded or
move easily.
• When large areas require reconstruction, fullthickness skin
grafts from expanded donor sites are recommended.
• Replacement of aesthetic units – the entire periorbital area
or the upper or lower lid – gives the best result .

51. Reconstruction in the breast, chest,
trunk, and extremities
• Tissue expansion was introduced by Chemar Radovan in 1982
to facilitate breast reconstruction in post mastectomy patients
because these patients were found to have insufficient chest
wall tissue for placement of the implant.

52. The hypoplastic breast
• Tissue expansion has played
an important role in the
reconstruction of both
acquired and congenital
breast hypoplasia.
• Management of the
deformity depends on the
degree of breast asymmetry,
the nature of the deformity,
the quality of the chest wall
soft tissue, and the age of
the patient at presentation.

54. The immature breast
• Management of young adolescents presenting with breast
asymmetry.
Adolescence is a critical time that is characterized by intense
social pressures and self awareness of a developing physique,
so failure to address the problem of breast asymmetry can
result in psychological problems. These patients do not need
full maturity for reconstruction.

55. Correction of Poland syndrome
• Poland syndrome involves
- abnormal development of the breast
- thoracic wall deformities
- deformities of the upper extremity
- vertebral anomalies.
• Poland syndrome exhibits a uniform absence of the sternal head of the pectoralis major muscle.
• Abnormalities in the anterior ribs and costal cartilages and deficiencies of the muscles of the scapular area,
including the latissimus dorsi.
• Other findings include deficiency of subcutaneous tissue; hypoplasia, aplasia, or
malposition of the nipple–areola complex; and deficiency of breast tissue.

57. Expansion of the trunk
• The trunk and abdomen are well suited to tissue expansion in individuals of all ages.
• Because of the large adjoining surface area from which tissue can be recruited, large prostheses
can be placed and flaps quickly expanded.
• Large deformities, such as burns, giant hairy nevi, and other congenital anomalies, the expanders
are inflated maximally and the flaps are advanced. The prostheses are left in place and re-
expansion is carried out in the subsequent weeks.
• In the abdomen, two or three serial expansions are usually well tolerated.

59. Expansion in the extremities
• Skin and soft tissues of the extremities tolerate tissue
expansion well.
• The capsule that develops adjacent to the expander has a
resilient surface that can be transposed over joints and
tendons to decrease adhesions.

60. COMPLICATIONS

61. IMPLANT FAILURE
• Despite design improvements, the use of an excessively large needle or
the inadvertent puncture of the implant can lead to implant deflation.
• To maximize sealing of the valve, the implant reservoir should be entered
at a 90° angle.
• If there is any question about the location of the inflation reservoir,
radiologic or sonographic techniques may be helpful.

62. INFECTION
• The introduction of bacteria to the wound in the perioperative
period is the most common cause of early infection.
• Areas susceptible to lymphedema, such as traumatized lower
extremities, carry a significantly higher rate of infection.
• An area of copious lymphatic drainage, such as the neck or the
groin, also tends to accumulate lymphatic fluid around a prosthesis
and is more susceptible to infection.
• If infection occurs late in the course of expansion, the prosthesis
can be removed and the expanded tissue advanced after irrigation
of the infected cavity.

63. IMPLANT EXPOSURE
• Implant exposure can occur both early in the postoperative period and after a protracted course of
expansion.
• Treatment of the exposed implant depends on the timing of exposure.
• Exposure early after placement is usually related to inadequate dissection or use of an excessively
large prosthesis that abuts on wound closure.
• If the prosthesis becomes exposed soon after placement, it is best to remove it and reoperate 3–4
months later.
• Late exposure is usually related to excessively rapid or overzealous inflation.
• If minimal or late exposure occurs during the course of expansion, the procedure can continue with
the use of antibiotic creams on the exposed area: In this situation, multiple, rapid fillings are done
to generate adequate tissue.
• Reinforcement of the compromised overlying skin with paper tape is sometimes helpful. Most flaps
survive and

64. COMPROMISE AND LOSS OF FLAP
TISSUE
• To ensure vascularity,one should attempt to
maintain a major axial vessel in the expanded
tissue.

65. Thank you