1. Journal meeting
Trauma Department of PRS in CGMH
11.17.2009
R4 Pang-Yun Chou, MDR4 Pang-Yun Chou, MD
Prof. Chih-Hung Lin, MDProf. Chih-Hung Lin, MD
November, 2009, PRSNovember, 2009, PRS

2. Introduction
• Evolution
– Random-pattern flaps
– Fasciocutaneous flaps
– Myocutaneous flaps
– Perforator flaps
• Manchot, Salmon, Cormack, Lamberty, Taylor, Palmer,
Morris, Tang…
• Ultimate goal of reconstruction
– Match optimal tissue replacement
– Minimal donor-site expenditure
– Maintain function
 Perforator flaps

3. Perforator flaps
• Koshima
– Began in 1989
• inferior epigastric artery skin flap with the rectus
abdominis muscle for reconstruction of floor-ofmouth and
groin defects
• Br J Plast Surg. 1989;42:645–648Br J Plast Surg. 1989;42:645–648
– Large skin flap
• Survive without muscle
• Based on a single perforator
• Kroll and Rosenfield
– Perforator flaps
• Blood supply from MC flap, without deteriorating donor site

4. Perforator flap
• Clinically, harvested as
– Pedicle perforator flap
– Free flap
• Over 350 perforatorsOver 350 perforators in body
– Diameter and length of source artery
– Location of pivot point
• Perforators
– Direction
– Axiality of flow

5. Perforators
• Taylor and palmer
– Angiosome concept
• Source artery  perforators itself
• Dynamic vascularity of perforator flapsDynamic vascularity of perforator flaps
• Limiation of static image
– Vascular distribution and flow characteristics
• Perforators
– Axiality of blood flow
– Connections with adjacent perforators
– Subdermal plexus and fascia contribution

6. Perforasome
• 3 years research
• 217 flaps, totally
• 40 fresh cadavers40 fresh cadavers
• Dissect by loupe
• Methylene blue
Texas Southwestern Medical CenterTexas Southwestern Medical Center

7. Materials and Methods
• Anterior trunks
– Internal mammary artery, superior epigastric artery, deep inferior
epigastric artery, and supraclavicular artery perforator flaps
• Posterior trunks
– Thoracodorsal artery, posterior intercostal artery, lumbar artery,
and superior and inferior gluteal artery perforator flaps
• Upper extremity
– Ulnar artery, radial artery, and posterior interosseous and the
Quaba flaps
• Lower extremity
– ALT, AMT, ATA, peroneal artery, and PTA perforator flap

8. Flap harvesting technique
• Trunk
– Harvested from midline to midaxillary line
– Anterior trunk
• 26 IMA flaps – supraclavicular to costal chondral margin
• 60 DIEP flaps
• 13 SEAP flaps – superior epigastrium to lower
– Posterior trunk
• TDA flaps
• LA flaps – T12 to iliac crest
• Extremity
– Skin incisions
• ForearmForearm -- made opposite the source artery
• ALT, AMTALT, AMT – groin crease to supra-patellar region
• Lower legLower leg – circumferential skin dissection

9. Dynamic 4D-CT
• 4D-CT angiography
– 3D-CT angiography + TIMETIME
• Scanned with contrast media just injected
• Characteristics and distribution of vascular perfusionvascular perfusion
• Flaps
– Placed skin downward
• Prevent pressure on the pedicle
• Minimize the risk of ↑resistance during perfusion
• Contrast media
– Heated to 373700
 ↓Viscosity, ↑ Vascular filling
– 2 to 5 ml/flap

10. Static 3D-CT
• Barium-gelatinBarium-gelatin mixture
– 100ml N/S to 404000
+ 3g gelatin
– Slowly adding 40g barium sulfate
– Vascular tree was saturated
– Flaps frozen at least 24 hrs before CT scan
• Static 3D
– Branching patterns of perforators
– Characteristics of linking vessels
• Dynamic 4D
– Axiality or preferential direction of flow

11. Results
• PerforasomePerforasome
– Each perforator has its
own unique vascular
arterial territory
• CT image
– Multiple direct linking
vessels
– Direction of flow
PerforasomePerforasome

12. First principle
• Two mechanism
– DirectDirect linking vessels
• Communicating directly from one perforator to the next
• Within the suprafascial and adipose layer
– IndirectIndirect linking vessels
• Recurrent flow through the subdermal plexus

13. Linking vessels
• Linking vessels
– Multiple perforasomes
– To one another
• Flow through
– CommunicatingCommunicating
branchesbranches
– Bidirectional
Injury to direct or
indirect
Perfusion maintainedPerfusion maintained
Dynamic 4D-CTDynamic 4D-CT

14. ALT to AMT, By Large direct linking vesselsALT to AMT, By Large direct linking vessels

15. AMT to ALT, Reverse perfusion, bi-directionalAMT to ALT, Reverse perfusion, bi-directional

16. ALT to AMT, By LVs, communicating branchesALT to AMT, By LVs, communicating branches

17. AMT to ALT, bi-directionalAMT to ALT, bi-directional

18. Sub-dermal plexus
• TaylorTaylor
– Choke vessels
– Indirect linking vessels
– Recurrent flow from
sub-dermal plexus

19. Indirect linking vessels
• Perforators
– Oblique branch, Vertical branch to subdermal plexus
• Indirect linking vessels
– Recurrent flowRecurrent flow from the subdermal plexus
Lateral viewLateral view

20. Communicating branches
• Communicating branches
– Coronal, sagittal, and transverse planes
– Confer a protective mechanismprotective mechanism to ensure vascular flow to skin
Transverse viewTransverse view

21. Second principle
• Flap design, Skin paddle orientation
– Based on the direction of linking vesselsdirection of linking vessels
• Axial in extremity
– Parallel to the axis of the limbs
– Flaps designed in parallel to axis of linking vessels
• Perpendicular to the midline in trunk
– TDA flap (latissimus dorsi muscle fibers), IMA flap
– Perforators follow a vertical row distribution
» Have contra-lateral ones
– Flow away from the midline for lateral vascularity
– Ant. and posterior midlines of trunk
» Heavily populated in perforators

22. Axiality
Thoracodorsal flapThoracodorsal flap
Forearm flapForearm flap

23. Lower leg
Anterior legAnterior leg Posterior legPosterior leg
Cross midlineCross midline Follow axiality of limbFollow axiality of limb

24. Trunk
Linking vesselsLinking vessels
Perpendicular to midline of trunkPerpendicular to midline of trunk

25. Abdomen
Transverse abdominal skin flapTransverse abdominal skin flap
Linking vessels, perpendicular,Linking vessels, perpendicular,
bi-directional fashionbi-directional fashion

26. Back
Perpendicular, cross midlinePerpendicular, cross midline

27. Third principle
• Preferential filling of perforasomes
– Within perforators of the same source artery
– Followed by perforators of adjacent source arteriesadjacent source arteries
• DB-LFCA  AMT  superficial FA perforasomes
• Vascular filling, density maximized, then spread-out
– Single large perforatorsSingle large perforators from a source artery
• Medial circumflex femoral artery
• Less axial vascular distribution

28. Preferential filling
Adjacent source arteriesAdjacent source arteries

29. Fourth principle
• Mass vascularity
– A perforator adjacent to an articulation
• Directed away from same articulation
• Radial A. perforator flap
– A perforator at midpoint between two articulations, or in trunk
• Multi-directional flow distribution

30. Direction of flow
• Vascular density
– ↓distally away from
• Midline of trunk
• An articulation
• Orientation of LV
– Orientation of vascular flow
• Perpendicular to midline
• Parallel to limb axis
• Perforator locationPerforator location
– Flap design
– LVs between two perforators
• Bi-directional flow
• Protection against injury

31. Discussion
• Each perforator
– Its own vascular territory, PerforasomePerforasome
– Multidirectional flow pattern
– Highly variable and complex
• Single perforator–based flap reconstructions
– Knowledge of individualindividual perforator vascular anatomy
• supersedes that of source artery vascular anatomy
• Perforasomes are linked
– Direct and indirect linking vessels
– Communicating branches
– ProtectionProtection from ischemia and vascular injury in case of trauma

32. Discussion
• Perforator flap harvested
– All branches from the source artery are ligated
– Results in hyperperfusionhyperperfusion ↑↑ vascular filling pressures
• Dilate the perforator itself
• Allow extensive interperforator flow
– LVs, higher than normal filling pressures
• Capture additional adjacent perforator vascular territories
• Perforator flaps designed at a midpoint
– Designed in multiple fashions
• Multidirectional perforator flow distribution
– Dense fibrous septae/ligamentous attachments over articulation
• Maintain skin stability and draping during flexion and extension
• Perforators directed away from the articulationaway from the articulation

34. Conclusion
• Every perforator has the potential
– Become either a pedicle or a free perforator flap
• HyperperfusionHyperperfusion of a single perforator
– Capture multiple adjacent perforasomes
– Large perforator flaps based on a single perforator
• Additional adjacent perforasome territories
– Captured through direct and indirect LVs by
hyperperfusion

35. Conclusion
• Perforasome theoryPerforasome theory
– Provides additional insight into the mechanisms of
perforator flap vascularity
– Serves to facilitate the understanding, design, and
clinical use of both free and pedicle perforator flaps

36. Thanks for your attention!