definition, classification,application, comparison

1. Flaps
By Sintayehu A. (GSR III)
Moderator: Ataklitie Baraki ( MD,FCS-ECSA
Plastic and Reconstructive Surgeon ,ALERT-FMoH)
10/10/2018 G.C

2. Outline
• Introduction
• Anatomy of the skin
• Reconstructive ladder
• Principles of flap
• Classification of flap

3. Introduction
• Grafts and flaps constitute the most commonly performed procedure
in plastic surgery.
• The routine use of grafts and flaps has dramatically broadened the
ability of the surgeon to perform reconstructive surgery and improve
outcomes and quality of life for trauma patients, burn patients, and
cancer patients.

4. Introduction contd. History

5. Anatomy of the skin
• The skin represents ~ 8% of TBW, with a surface area of 1.2–2.2 m2.
0.5–4.0mm thick and covers the entire external surface of the body
• Has two distinct layers :epidermis and dermis

6. Epidermis
• Varies in thickness from 0.04mm in
the eyelids to 1.6mm in the palms.
• No blood vessels and relies on
diffusion from underlying tissues.
• Principal function of epidermis is protection
by the process of cornification,
producing layer of dead cells.

7. Dermis
• Mainly composed of collagen, elastic fibers and ground substance.
• Contains all the nerves, vessels, lymphatics and most of the glandular
elements of the skin.
• The mechanical behavior, i.e the ability to stretch, resilience of the skin is
primarily related to collagen & elastin content.
• Mature dermis has two layers : superficial papillary and deeper reticular
layer.

8. Blood Supply of the Skin
• The cutaneous arteries arise either directly from the underlying source arteries, or
indirectly from branches of those source arteries to the deep tissues, forming subdermal
plexus.
• Direct cutaneous vessels
• Fasciocutaneous
• septocutaneous
• Indirect cutaneous vessels
• Musculocutaneous

9. Contd..
• Angiosome is a 3D composite block of tissue supplied by a main
source vessel
• adjacent angiosomes are linked either by
• choke anastomosis : reduced caliber
• true anastomoses: normal caliber
• Choke vessels serve to regulate blood flow between
neighboring angiosomes and can potentially dilate to the caliber of a
true anastomotic vessel after surgical delay or with a decrease in
sympathetic tone.

10. Reconstructive Ladder
Provides systematic approach to wound
closure.
Emphasizes selection of simple to complex
techniques based on local wound
requirements and complexity.
Each option is considered based on viability,
risk of complication and best functional and
aesthetic result for the patient

11. Terminologies
• Autografts – A tissue transferred from one part of the body to another.
• Isograft / Syngraft- The donor and recipient are genetically identical e.g.
monozygotic twins
• Homografts /Allograft – tissue transferred from a genetically different
individual of the same species.
• Xenografts – a graft transferred from an individual of one species to an
individual of another species.

12. Flap
• A flap is a vascularized block of tissue that is
mobilized from its donor site and transferred to another location,
adjacent or remote, for reconstructive purposes
• Term “Flap” :
from Dutch word “FLAPPE” which means “anything that hung broad and loose,
fastened only by one side
The part of a flap that contains the blood supply is called a Pedicle and serves
as the base of the flap.
• Flaps Can contain multiple types of tissues including skin, muscle,
nerve, fascia and bone

13. Flaps versus Grafts

14. Indications for flaps
• When primary repair is unobtainable,
• The wound bed is not amenable to grafting(such as those with
exposed bone or tendon) or
• The aesthetics are unfavorable for grafting
• In order to restore function
• Covering vital structures

15. Flaps contd.
• Advantages
1.They provide blood supply to the
recipient site
2.They provide tissue bulk at a
defect
3.They can provide sensation to the
recipient site
4.They have no contracture, are
durable and the site can be re-
explored for secondary procedure
without tissue loss
• Disadvantages
• May lead to fat deposit where it is
not necessary
• May require multiple procedures
such as in distal flap

16. Factors to be considered during flap choice

17. Flaps are used to
1. Replace tissue loss due to trauma or surgical excision
2. Provide skin coverage through which surgery can be
carried on latter
3. Provide padding over bony prominences
4. Bring in better blood supply to poorly vascularized
bed
5. Improve sensation to an area (sensate flap)
6. Bring in specialized tissue for reconstruction such
as bone or functioning muscle

18. Classification of Flaps
• Can be based on (five ‘C’ s)
1. Contiguity- source
2. Contour – methods of transfer
3. Components- compositions
4. Circulation
5. Conditioning

20. Based on Contiguity (by their source)
Local – immediately adjacent to defect, shares a side with the defect
Regional – near the wound but not adjacent to it
Distant – moved from remote anatomic area, done when local tissue is
insufficient to cover an adjacent defect
Pedicled – moved with intact tissue bridge for support
Islanded – moved under the skin for
non contiguous defects
Free flap: free tissue transferred to another site
the arterial blood supply should be at least 1 mm in diameter. The
microvascular anastomosis of the artery helps to restore the blood supply of
the recipient site.

21. Contiguity:
• Local flaps:- are composed of tissue adjacent to the defect.
– Used to cover skin defects in areas without enough tissue laxity
to afford primary closure.
– Most local flaps are random pattern flaps with no specific named
vascular supply.
– E.g. rhomboid flaps, V-Y flaps, and Z-plasty

22. Contiguity: contd.
• Regional flaps:- are composed of tissue from the same region of the
body as the defect and are musculocutaneous mostly.
• E.g.:- Forehead flap for nasal tip reconstruction based on the
supraorbital and supratrochlear vessels including the glabellar and
frontalis musculature.

23. Contiguity cont
• Distant flaps
– Pedicled distant flaps are from
a distant part of the body to which
they remain attached.
– Free flaps are completely detached
from the body and anastomosed
to recipient vessels close to the defect

24. Contour:
• Flaps can be classified by the method in which they are transferred
into the defect and these includes
• Advancement:-
methods used to facilitate advancement of
a flap into a defect
• Stretching of the flap
• Excision of Burow’s triangles at its base
• A counter incision
• Z-plasty at its base
• A combination of the above.

25. Contour
• Transposition:- the flap is moved
into a defect from an adjacent position,
leaving a defect which must
be closed by another method.
• Interpolation:- these flaps are moved
into a defect either under
or above an intervening bridge of tissue.

26. Contour contd…
• Rotation:- the flap is rotated into the defect.
• Classically, rotation flaps are of
sufficient dimensions to permit
closure of the donor defect.
• Many flaps have elements of transposition and rotation and may be
best described as pivot flaps.

27. Contour
• Crane principle:- this technique aims to transform an un-graftable bed
into one that will accept a skin graft.
• At the first stage a flap is placed into the defect.
• After a sufficient time period to allow vascular ingrowth into the flap
from the recipient site, the superficial portion of flap is replaced in its
original position.
• This leaves a segment of subcutaneous tissue in the defect, which can
now accept a skin graft.

28. Classification based on Circulation
• Vascularity is the most valid method of flap classification (most
critical determinant of successful flap transfer)
• Random flaps are based on the subdermal plexus and are traditionally
limited to 3:1 length-to-width ratios.
leg 1:1 poor blood supply, face 1:6
• Axial pattern flaps contain a single direct cutaneous artery within the
longitudinal axis of the flap.
• Reverse-flow axial pattern flaps are axial flaps in which the source vessel is
divided proximally, and blood flows in a retrograde fashion through the distal
vessel. This is made possible by venae comitantes, bypass vessels, and
valvular incompetence.
• Island flaps are axial pattern flaps raised on a pedicle devoid of skin to
facilitate distant transfer.

29. Circulation contd.
• Axial pattern flaps: longer than random flaps and preferred when
there is need for a long flap to be made.
• contain a named artery running along the axis of the flap in the subcutaneous
tissue.

30. Axial pattern flaps contd.
• Examples include:
• The groin flap based on
the superficial external iliac vessels.
• The deltopectoral flap based on perforating vessels of the internal mammary artery.
• Both flaps can include a random
segment in their distal portions after
the artery peters out.

31. Axial flaps contd.
Fasciocutaneous flaps: are based on vessels running either within or
near the fascia.
• Blood reaches these flaps from fasciocutaneous vessels (also called
septocutaneous vessels) running from the deep arteries of the body
to the fascia.
• The fasciocutaneous system predominates on the limbs and this is
the location of most of these flaps.

32. contd.
• Skin flaps can be classified simply as a direct or an indirect perforator
flaps
Direct perforators: pierce the deep fascia without traversing any deeper
structures.
Indirect perforators: pass through deeper tissues, usually muscle or septum,
before entering the deep fascia.
Perforator flaps: Consist of skin or subcutaneous fat supplied by
isolated perforator vessel.
May pass from their source vessel either through or between the deep tissues

33. Perforator flaps contd.
• three categories based on the three different kinds of perforator
vessels
 Indirect muscle perforator: Myocutaneous perforator flap
 Indirect septal perforator: Septocutaneous perforator flap
 Direct cutaneous perforator: Direct cutaneous perforator flap
• are named for their nutrient vessel (e.g., deep inferior epigastric
perforator [DIEP] flap or
• named for its anatomic region or muscle where multiple perforator
flaps can be raised from a single vessel (e.g., anterolateral thigh [ALT]
flap).

34. Neurocutaneous and venocutaneous flaps
• Skin flaps based off the perforating arteries accompanying cutaneous
nerves and veins. e.g., sural nerve and saphenous vein flaps
• Commonly used as pedicled flaps for coverage of local or regional
extremity defects
• the saphenous flap, is based on the short saphenous vein and often
used to reconstruct defects around the knee.

35. Types of Venous flaps
Type I is an unipedicled venous flap, or a pure venous flap with a single
cephalad vein as the only vascular conduit.
Type II :bipedicled “flow-through” flaps with afferent and efferent veins
exhibiting flow from caudal to cephalad.
Type III : arterialized through a proximal arteriovenous anastomosis
and drained by a distal vein.
Applications: skin defects or both skin and vascular defects in hand
surgery, skin and tendon defects in hand surgery, reconstruction of
finger pulp,

36. Components:
• Flaps can be classified by their composition, as:
– Cutaneous:- used to cover skin defects in areas without enough
tissue laxity to afford primary closure.
– Fasciocutaneous:- are based on vessels arising in fascial
planes(fasciocutaneous plexus) in between muscles and do not
intrinsically include any muscle in the design.
– Can be used as pedicled flaps for coverage of local, regional, and
distant defects, or as free tissue transfer flaps

37. Muscle and myocutaneous flaps
• can be transferred as pedicled flaps or as a free tissue transfer based
on their dominant vascular pedicle
• primarily used for breast, head and neck, and pressure sore
reconstruction. Also radiated, or traumatic wounds
• Mathes and Nahai developed a classification of muscles based on
circulatory patterns in 1981

38. Muscle and myocutaneous flaps contd.
• Type I, III, and V muscle flaps have the most reliable vascularity.
• Type II and IV muscle flaps are less reliable because the vascular
pedicle to distal muscle must be divided to achieve adequate arc of
rotation

39. Vascularized bone flaps
• can be transferred in a pedicled or free fashion based on their
nutrient vessels.
• Most commonly transferred vascularized bone flaps:
• Fibula (peroneal artery)
• Iliac crest (deep circumflex iliac artery)
• Scapula (transverse branch of circumflex scapular artery)
• Radius (radial artery)

40. Components contd.
• Visceral flaps:
• The omentum, colon, and jejunum can be transferred as visceral flaps based
on their dominant pedicles or vascular arcades.
• Intestinal flaps are primarily useful in pharyngoesophageal reconstruction.
• Innervated flap:
• Functional flaps created by including motor or sensory nerve after transfer
• the original tension and length/width ratio of the fibers need to be
recreated during inset.
• gracilis, latissimus dorsi, and serratus muscles are often used for functional
muscle transfers

41. Conditioning: surgical delay
• Delay’ is any preoperative maneuver which will result in increased flap survival.
• Delay Phenomenon is used to extend the restricted size of random flaps and maximize
survival of extended axial-type flaps
• Surgical flap delay is accomplished in two ways:
• Standard delay:- achieved by interrupting a portion of the normal blood supply to the flap
without transferring the flap from its native position
• with an incision at the periphery of the cutaneous territory.
• partial flap elevation.
• Strategic pedicle delay:- involves division of selected pedicles to the flap to enhance
perfusion through the remaining pedicle or pedicles. e.g pedicled TRAM flap

42. Conditioning contd.
• MECHANISM OF INCREASED BLOOD FLOW IN FLAP DELAY
1. Increased axiality of blood flow:
Removal of blood flow from periphery of a random flap promotes development of axial
flow.
2. Opening of choke vessels.
3. Tolerance to ischemia :
adaptive metabolic changes at a cellular level within the
tissue.
4.Sympathectomy vasodilation theory :
leading to vasodilation.

43. Conditioning: tissue expansion
• when tissue is subjected to prolonged stretching by implanting
tissue expander viscoelastic deformation and true tissue growth
expands tissue.
• Indication: breast reconstruction, scalp lesions like alopecia, planned
skin or muscle flaps
• Advantages:
• It recruits local skin, which provides the best colour, contour and hair match
(where important).
• The tissue can be functional with a robust blood supply and intact nerve
supply.
• Donor closure potentially leaves a simple linear scar

44. Flap monitoring
• Venous insufficiency is the most common cause of flap failure
• failure rate of free tissue transfer is reported to be less than 5%
• more successful salvage within the first 24 hours after initial surgery
• Hourly monitoring for 24hrs then 4hrly for 48hrs

45. References