CLOSURE OF RHOMBOID SKIN DEFECTS: THE FLAP~, OF

Transcription

CLOSURE OF RHOMBOID SKIN DEFECTS: THE FLAP~, OF
British ffournal of Plastic Surgery (197’0, zS, 3oo-3 ~4
CLOSURE OF RHOMBOIDSKIN DEFECTS: THE FLAP~,
OF LIMBERG AND DUFOURMENTEL
ByG. D. LISTER, M..B., F.R.C.S.(Ed.&Eng.)
and T. GIBSON,D.Sc.,/VLB.,F.R.C.S.(Ed. &Glasg.)
Westof ScotlandRegionalPlastic andOralSurgeryUnit,
Canniesburn
Hospital, Bears&n,Glasgow
IN excising the majority of skin lesions, surgeonscreate an elliptical
can be closed directly. As the lesions increase in size, however, there comes
wheneither the long axis of the ellipse becomestoo long for the local
cosmetic result, or the short axis too wide to permit direct suture. In
instances the excisional outline maybe replanned and closure obtained with
flap, until of course the defect becomesso large that cover can only be
imported skin.
Designingsuch local flaps, particularly whenthe secondarydefect is to
directly, can tax the skill of the most experienced plastic surgeon. Only
trial and error does he learn intuitively to judge the maximum
tension under
can suture the pardy devascularised flap and the absolute limits to which
stretch the surroundingskin ; the art of designing such flaps takes long to
is hard to teach.
There are, however,2 exceptions to whichwewouldlike to draw
the flaps designed by Limberg(I 946, 1966, and 1967) and by Dufourmentel
to close rhomboiddefects. A rhombusis an equilateral parallelogram and
regarded as an" ellipse with straight sides .". Rhomboid
excision has so
over elliptical excision particularly whenthe defect is to be closed with a
For example,less normalskin needsto be excised in the long axis, the designand
of a straight-sided flap is far simpler than that of the round flap and rhomboid
lends itself to the technique recommended
by Borghouts(1964) of histological
lion of the specimen margins to check mmourclearance.
The Limbergflap and the Dufourmentelflap are different in design and
and will be described and discussed separately.
THE
!LIMBERG
FLAP
The flap which Limbergdesigned for a rhomboiddefect is one extension
classical studies on transposed triangular flaps. Thusin Figures I and 2 the
dosed by interchanging the unequal flaps TLWand UVW.The design may
regarded as a rhomboidflap XUVW
of the same size and shape as the defect into
it is to be rotated.
The flap whenused singly is suitable for closure only of rhomboid
angles of 60° and I2O° ; in this paper such a defect is called a 60° rhomboid.
rhombusis thus composedof 2 equilateral triangles and the short axis is
length as each side.
In constructing the flap (Fig. I) the short diagonal is extendedin one
direction by its ownlength to the point V. A further incision VWparallel to
equal to each of the sides completes the design. It will be evident that the
UW
is also equal to the short diagonal[ of the defect and therefore to all other
in the plan. All attractive aspect of this Limbergflap is that, oncethe len
diagonal has been determined, the. remainder of the design maybe completedby
calipers set to that length.
3oo
Foran’.
~s shownin
rotated thr.c
areaP~=:,-x~
thesepoints
in turn de~
~onsideratie
¢xtensibilit)
at right ang
as at righta
its ownlenl
t~pthe skin
~houldif
primary
Fig.4, a).
withthe po:
ttowever,v
&rthe rho:
Lirnbe
anglesand
l.imberg’s
:
modelsprc
~aut,slight
~hornboid
CLOSURE OF RHOMBOID SKIN
FLAPS
~tical
,~erecomes
ii
local
z. In
ained with
be
DEFECTS
301
For any given 6o° rhomboiddefect there are theoretically 4 Limbergflaps available
shownin FigUreo3.Oncethe most appropriate flap has been chosen and raised it is
--~ ,hrou~h
6o and placed in the defect (Fig. 2). It will be seen that U and
o
totat~u "
~ a~proximatedin closing the secondary defect. If Nllowsthat the ease with which
~k~ts
be apposed
determ~esavailabfiky
whether or and
not ex[ensib~ity
the design isof appropriate
t~s
mrn can
dcpends
on the relative
the skin. A ;major
~nsiderafion. in planing should therefore be to seek out the d~ecfion of maxim~
~tensibilit~ xn t~e skin ~r2und,~defect (gibso~ et ~l., z~69~. This line is usually
right angmsto ~anger s ~mes~umsonet at., ~97~) ana on merace it maybe regarded
~ at right angles to the crease ~es. It maybe readily determ~edclinically by pic~g
%ctis to
Only
on under
~
to which
long to
mentel
)gram and
as some
=l wit_ha local~i
~ design and
[rhomboid ex’~i~
.lstologlcal
ex~
;ign
and appli~~
V
Fro. i. Design of a Limberg flap. STUXrepresents
a 60° rhomboid defect. SU is extended by
,ts ox :~ ;:ngth to V. "qWis then drawn parallel and equal to UX. Note that the distance between
any 2 adjacent points in the design is identical.
~ne extension
c and 2 the defee~jli~
the skin between finger and thumb. Havingfi~und that line, the points U and W
: design may .a~.~ ~p
*h0uld
if possible be placedon it ; they lie on the sameline as oneof the sides of the
:he defect into
primary defect and ~ flaps can be designed in this fashion for any one 6o° rhomboid
Fig. 4, A). If the lesion is circular, the rhomboidcan be rotated giving ~ moreflaps
omboid
defe~~
"*’ith
the points Uand Win the sameline of maxim,am
extensibility (Figs. 4, B and4, c).
°
6o rhomboid.
ttowever,
when
the
shape
of
the
lesion
already
determines
the positioning of the rhom~ort axis is the
Midthese remarksare not appropriate and one selects the most suitable flap available
’.’or the rT, omboid
so positioned.
~ded in one or
Limberg
pointed
out that movingany flap inwflves but 2 processes, opening wound
gr parallel to
ingles and closing woundangles. Closing a woundangle produces a dog-ear or, in
!ent that the dii~ I.imberg’s more precise term, a standing cone. Openingan angle in Limberg’spaper
: to all other
modelsproduces a lying cone. This cannot forra in skin ; what usually occurs is a
~he length of th~ :aut, slightly depressed area around the angle. If for exampleone were to close the
)e completed by.~
:homboiddefect shownin Figure I directly, dog-ears would form at points T and X
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BRITISH JOURNAL
OF PLASTIC SURGERY
and depressed areas at S and U. By adding the rhomboid flap for closure
avoids any movementof angles T and S. This can bc of cosmetic value,
i~ the deformations aroundthe other angles can bc placed in less obtrusive
v
FIG.
12.
A,
B
C
the flap designed in Figure I has been cut and transposed into the defect.
post-operatively.
C, z weeks post-operatively.
LME
PRACTICAL
APPLICATIONS
Excisional Surgery. In most cases it is possible to decide in advance
skin lesion will require elliptical excMonand direct closure, excision with
closure or excision and distant skin cover.
Where doubt exists about the practicabilky of direct closure k is wise to
only the lesion with appropriate clearance as the initial step. If apposition then
that direct closure is feasible further excision to create an ellipse suitably long to
Fro. 4. \V
Fig. I) lie,
~a ~e so s
CLOSURE
OF RHOMBOID SKIN
DEFECTS
303
losure
[ue,
;lV~
FIG. 3. In theory a
choice of 4 Limberg
flaps is available for
any 6o ° rhomboid
defect.
LME
LME __
J__~
~tefect. B, 6
_
vance
a with local
is wise to
;ition then
bly long to
t;I..~. 4. With roughly circular lesions the rhombus should
rlg: I) lie on the line of maximumextensibility.
There are
~n t~e so sited (A and B) and thus 4 flaps of this kind are
applicable if the shape of the lesion dictates the
be so positioned that points U and W
~ possible ways in which the rhombus
available (C). This of course is
position of the rhombus.
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JOURNAL OF PLASTIC
SURGERY
Fro. 5. A, Two alternative Limberg flaps have
been designed.
The 2
others theoretically available would encroach upon
the ear. B, Direct closure
~va8 felt to involve suturing under undue tension.
C, The more suitable flap
was chosen, cut, transposed
and sutured,
(D and E)
with good result.
the formation of permanent dog-ears is performed. If direct closure is form
inapplicable no normal tissue has been discarded needlessly and a flap
designed can be cut and rotated into position (Fig. 5).
At the other extreme of applicability,
it may be found that U and W
.~ :s. 6. Adefect in the formof a parallel:,r:am, havingacute angles of 60° and long
~,3~ twice that of the short, cart be closed
,.:.~., Limbergflaps. The5 possible designs
are shown.
A
OSLlreJS
ad a flap
U and
W
B
C
~" "- A parallelogram defect created by excision of a rodent ulcer closed by ~ Limbergflaps.
distortion of the eyebrowor irregularity of the hairline wasavoided by the choice of flaps.
Any
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JOURNAL OF PLAsTIc
SURGERY
approximated even after undermining. The flap must then be replaced
alternative means of skin cover found. With a little experience, however,
Occurs.
The Simultaneous Use of 2 Limberg Flaps. Any defect which can be
as a parallelogram the long side of which is twice as long as the short side,
angles of which are 6o°, may be closed with 2 Limberg flaps.
FiG. 8. A circular
defect may
be considered
as a hexagon.
Each side equals the radius of
the original circle in length.
measured a~
limbs pointi
should 2 sh~
positio.n,,an
is crc’:. :.
ulcero’~
occurred.
On oc~
undesirable
Gillies fan f
FIG. 9- All equilateral hexagons
are made up of three 6o° rhomboids. Three Limberg flaps can
be constructed to close a hexagonal
defect. Preferably the peripheral
limbs should point in the same
direction.
FIG. IO. Construction where 2
of the flaps have peripheral limbs
pointing towards one another.
This may be necessary anatomically,° but the angle closed at A is
12o and will produce a dog-ear.
FtG. 8
>
FIG. 9
FIG. IO
There are 5 possible constructions (Fig. 6) ; the choice will depend
anatomy and the availability of skin. A clinical example is shown in Figure 7.
The Simultaneous Use of 3 Limberg Flaps. A circular defect closely
to the form of a hexagon, the length of the radius equalling the length of each
sides (Fig. 8). All such equilateral hexagons are made up of three °
3 Limberg flaps can therefore be designed to close the defect (Fig. 9). In this
the calipers are invaluable ; set to the radius of the circular defect 18
teukoplakiao
that no furtt
which was n:
a commonb
Altho,u.~h
it
flap of~uc~
have -. a d/
i’:;;2erP,
and free skir
backs while
becauseof tl:
ts divided in
and further
replaced
however,
h can be
rt side, andi
ar defect
S a
the radius
:le in length.
CLOSURE
OF RHOMBOID
SKIN DEFECTS
3O
7
tneasured and markedand the design completed. The flaps should have the peripheral
in the same direction as in Figure 9. Only in s pecial circumstances
limbs19ointing
~hould~ share a common
base (as at a in Figure IC.) since, whenthey are rotated into
~POScrition
~:zo° is closed
and a pronounced
probablypermanent
, an
theangle
caseofillustrated
in Figure
~, excisionand
and
a " dog-ear
g raftin
g of radlonecrotlc
"
¯~ eared.
. In
.
ulcer , .: backhad previously beenperformed,but the graft failed and further necrosis
~x-currcd. "fhe ulcer was again excised and successfhlly closed with 3 Limbergflaps.
On occasion closure of a defect maybe quite feasible technically but mayhave
undesirable results. In the case shownin Figure ~:z the patient had previously had a
Gillies fan flap rotated at the left angle of his mouthand nowpresented with active
ateral hexagons
hree 60° rhom-~
nberg flaps can:
:lose a hexagonal
y the peripheral
int in the same
ion.
~ction where
s one another.
essary anatomic;e closed at A is’
~duce a dog-ear.i~
Flc,. z t. A, A circular radionecrotic ulcer of the back was excised as an equilateral hexagon and 3
I.i:.
flaps designed as in Figure xo. B, The defect excised and the flaps cut. C, Flaps transposed and sutured with, later, (D) sound healing.
A
FIG.
IO
rill dependon
wn in Figure 7.
:ct closely
-, length of each
°aree 6o
~Fig. 9). In
defect 18
l,’ukoplakia of the opposite commissure.WhileexcMonwas indicated, it was important
:hat no further narrowing of the mouthshould result. Three Limbergflaps, one of
ahich was mucosal, gave an acceptable solution. The 2 skin flaps were designed with
~ common
base, however,and this resulted in the ,creation of a dog-ear as predicted.
¯ }tthoughit cannot be easily appreciatedin black and white photographs,the use of the
:Up of buccal mucosaserved to reconstitute the vermilion in a mannerwhich would
bare beendifficult to achieve by other means.
1 .,. IVebs. Moderatedegrees of finger webbingare usually treated by release
¯ nd flee skin graft or by Z-plasty. However,a free graft has certain inherent drawNcks while a Z-plasty maynot introduce sufficient tissue into the line of the web
becauseof the limitation in length of the central limb. It was noted that, whena web
’-~ divided in the midline (Fig. ~3) and the fingers separated, the defect is rhomboid
a~adfurther that there is frequently sufficient skin on the sides of the fingers adjacent
the we
favoris
In o
l~ave
,k-sign ar
:rodthe f.
~upplyis
.my of
,:k~cd
~’~ndar,
readih
hair
=any di£
:F~nwitk
The
~mcourag,
FIG.12. A, Excisionof leukoplakiaof the .commissure
is planned.Twoskin flaps and(B)
mucosal
flap designed.C, The2 skinflaps witha common
baseas in FigureI I has resultedin a
dog-ear.D, Furthernarrowing
of the stomahas beenavoidedby reconstructingthe vermilion’
commissure
withthe buccalmucosalflap.
~re a
If co
:~ults
CLOSUREOF RHOMBOID
SKIN DEFECTS
309
Wthe web to supply a Limbcrg flap large enough to give good correction. The limiting
factor is again the amountof skin available, but this is easily assessed in advance.
FIG. 13. A, Midline incision of a finger web burn
contracture resulted in a
rhomboid defect when the
fingers were separated. B,
A flap designed on the
adjacent finger was cut,
transposed
and sutured
into place (C).
DISCUSSION
,s and (B) one
esulted in
the vermilion
In our experience of over 5° cases in which the Limberg flap has been used, we
have found it safe, reliable and versatile. One great merit of its geometrically precise
design and the fact that only one measurement is needed to construct both the defect
and the flap, is that it is so easily taught. The trainee has the assurance that the blood
~upply is adequate and that the edges to be apposed will fit together precisely without
any of the adjustment so often required in placing other flaps ; in other words, the
ttap vi!! " work".
¯ ,, :.major limitation of the Limberg flap is that the secondary defect must be
closed directly and flap placement cannot be eased by the use of free grafts on the
~condary defect ; the size depends directly on the awdlability of skin in the area. A
further limitation, common
to all local flaps, is that the correct quality of skin maynot
be readily available, for exampleafter excision of lesion’,; of or near the eyelids and close
to hair margins. At the same time because the Limberg flap can be designed in so
raany different directions, it is more often possible to construct a flap of the right skin
than with less versatile designs.
The final scar follows a slightly bizarre line whichcannot all be lost in crease lines,
but ;., ~aost cases the quality of the scar has been good without spreading or hyper:ropl:. ad the result has certainly been better than that obtainable by the simplest
~hernadve, a full thickness graft. Theoretically the shape of the Limberg flap should
encourage the formation of a raised " trap-door " scar. Whether the increased tension
~mposedon the flap prevents this is not known,but we have only seen it on one occasion,
:~here a rather small flap was used.
If correctly executed and if good primary healing occurs, the Limbergflap produces
:esults which, for colour and texture match and overall[ appearance, are excellent.
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JOURNAL OF PLASTIC
THE DUFOURMENTEL
SURGERY
FLAP
Whereas the Limberg flap can only be constructed for a 6o° rhomboid
Dufourmentel flap, " ’ le lambeau en L pour losange ’ dit ’ LLL’ ", can, in
used for any rhomboid. The rhombus is thus composed of two isosceles
unlike the Limberg construction, the short axis of the defect need not equal
its sides. The procedure may be regarded again as transposition
of two
flaps or more obviously the rotation of an irregular quadrilateral flap into a
defect.
In planning the Dufourmentel flap, the short diagonal LN (Fig. 14)
other of the adjacent sides of the defect KNare extended and the angle so!
bisected by a line (NQ) equal in length to each of the sides of the defect.
line (QR) is then drawn parallel to the long axis of the defect and again equals
each side of the defect. Calipers are: of some use in constructing the flap
incisions are of equal length, l:.ut a protractor is necessary to place the
accurately. Once raised, the flap KNQRis transposed into the defect.
in Figure 15, 4 Dufourmentel flaps can be planned for any rhomboid
the 4 angles of the defect come to equal one another, as the rhomboid
shape of a square, flaps may be designed at each of the 4 angles giving 8
(Fig. 16).
The merit of placing the equivalent points N and R in the line of
extensibility has already been discussed in considering the Limbergflap.
complicated with the Dufourmentel design ; indeed, on initial consideration,
to be quite impractical, since the relationship of the baseline of the trian
defect varies as the shape of the rhomboid varies. However, as the geometrical
of the design given as an appendix to this paper shows, the angle between
axis of the flap (NR) and the short axis of the defect (LN) changes by
degrees from 15o° as the acute angle of the defect varies from 6o° to 9o°. Thisi
may be ignored and, in practice, having determined the line of maximumskin
bility, points N and R may be placed upon it and the short axis of the
angle of I5o° to that line. Tiffs applies only to those cases in which the
the rhombusis not dictated by the shape of the lesion.
As the acute angle of the defect falls below 6o°, the Dufourmentel flap
progressively wider than the primary defect. Little is to be gained therefore
use of the flap in these circumstances and direct closure is to be preferred.
As the acute angle of the defect increases from 6o°, the defect becomes
wider than the flap and when it reaches a square the short axis of the flap is
quarters the length of the short axis of the defect. It is in this range that the
clinical value.
may prov
dosed
PRACTICAL APPLICATIONS
As shown above, the Dufourmentel flap has no practical value where
angle is less than 6o°. In closing a 6o° rhomboid defect, it has no advantage
Limberg flap, although it has been argued in its favour that it has a safer blood
than the Limberg flap because its base is wider. Embarrassment of the blood
of a Limberg flap, however, is rarely seen anywhere on the body and never on
It is in closing defects the acute angle of which lies between 6o° o°,
and 9
that the Dufourmentel flap is of use. Such defects are not often created as
excision is usually possible to convert the defect to a 6o° rhomboidwhich can bel
with the simpler Limberg flap. Where, however, such additional excision is
indicated, for example by the proximity of vital structures, then a
One r
be.ing60° ~
Dufourme:
learn and
Dufourme:
l.imberg i
CLOSURE OF RHOMBOID SKIN
:homboid
", can, in
osceles
:d not equal
3n of two
flap into a
(Fig. 14)
the angle so
he defect.
~gain equals
ing the flap
lace the flap
le defect.
homboid
nboid
giving 8
fine
:rg flap. This
nsideration,
e triangular
te geometrical
gle between
ages by less
DEFECTS
3I~
~rovide a satisfactory solution. Such a procedure for a defect whichcould not be
r directly withoutunduetensionis shownin Figurex7maYdo~ed
~
.... ¯ ~,~,~.,~
q
F),
I
I
:
FIG. 14
O°
. 9
~ tO
aaximumskin
ds of the
which the
armentel flap b~
aed therefore
preferred.
becomes
F the flap is only
:ange that the
FIG. 14. Design of a Dufourmentel flap. LMNKrepresents
a rhomboid defect.
LN and
KN are extended and the angle
thus formed bisected by a line
NQequal to each of the sides of
the rhomboid. QR is then drawn
of equal length and parallel to
the long axis of the defect MK.
FIG. 15. In theory a choice of
4 Dufourmentel flaps
is available
for any defect approximating to
a 6o° rhomboid.
value where
no advantage
~as a safer blood
mt of the blood
7 and never on
~ 60° o°,
and9
en created as
oid whichcan be i
onal excision is
,en a Dt
FIG. 16. If the defect is square
in shape a choice of 8 flaps is
available.
Fm. 16
DISCUSSION
~:~.e major merit of the Limbergflap is the simplicity of the design, all angles
being 6o° or ~zo°, all sides being equal. This rnakes it easy to learn and apply. The
Dufourmentelflap is by no meanscomplicated, but it is certainly more difficult to
learn and to plan than the Limbergdesign. Indeed, at first sight it.seems that the
Dufourmentel
flap with its angles rarely matchingthose of the defect is inferior to the
Limbergdesign, but this is too superficial a view. In both instances a defect is
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BRITISH
JOURNAL OF PLASTIC
SURGERY
closed an,
t,znsion;
by the en,
In its
flap!"
more
the defect
obtuse an:
the obtus~
become
cited by t
~mto h’,
The:
corn[" ~i ~cr
A
B
The ]
dderation
knowledge
fortunate
age group
far-closed
cosmetical
As th~
trend has
from Figm
Varial
angle of a:
D
C
FIG. 17. A, A Dufourmentel flap has been designed
for a planned
rhomboid excision having
an acute angle of 75° . B,
Direct closure would have
involved suturing under
considerable tension.
by o::c
l "arial
tcadity see
With each
equal whet
Since
I44 , the a1
l~.v plotting
~zcs which
l"l,~p
,,.,..
Fro. 17. C, The flap was
cut, transposed and sutured (D) with good result
(E).
In oth,
~hisis negli
CLOSURE
OF RHOMBOID
SKIN
DEFECTS
313
dosedandin closing
it thesurrounding
skinis stretched
andputunder
increased
t~sion
carefully
planned
andmeasured
mayhavechanged
considerably
; theangles
bytheendoftheprocedure.
" In i,s range of usefulness between60° and 9o°,the acute angle of the Dufourmentel
lta-; -ws more acute than that of the defect, while the obtuse angle of the flap is
moreobtuse than that of the defect. But imagine point L being pulled to point N as
the defect is closed ; the acute angle of the flap wouldtend to becomeless acute, the
obtuse angle less obtuse, while the acute angle of the defect becomesmore acute and
~he obtuse angle more obtuse. In other words the angles of the flap and the defect
becomemuchmore congruous. Unfortunately this variation in angle size is complicated by the closure of the secondarydefect ; app,’oximatingpoint Nto point R would
.~rn to havethe opposite effects on the angles than bringing L to N.
The matter is obviously very complex; even if we had simple reliable methods
of rnc:~,.wingextensibility of skin at any onesite and the effect of varyingtensions on
~, th, , ..".y, sis and prediction of the exact behaviourof either flap wouldrequire a
,-omputerrather than a plastic surgeon.
TheDufourmentel
flap is probablythe better design in so far as it takes into consideration the effects of increased tension on the skin, but until wehavemoreprecise
knowledgeof the latter both designs are still to someextent empirical. It is perhaps
fortunate that the majority of cases in whichthe tlaps havebeen used are in the older
age group and old skin absorbs unequalangles, unequalsides, too-far-opened and toofar-closed angles in a way whichmakessuch flaps, with their various shortcomings,
~smeticallyso successful.
APPENDIX
MATHEMATICAL
CONSIDERATIONS
IN THE DuFOURMENTEL
FLAP
Astheangles
ofthedefect
varysodo themeasurements
oftheflap.
Thegeneral
t~¢nd
hasbeengiven
in thetext,
butthemathematical
variations
arcreadily
derived
fromFigure18, A.
Variationof the Acute Angleof the Flap(/3) with that of the Defect (~.). /3 is one
angle of a right-angled triangle the other angle of whichis equal to Y/4. Since
y = ~8o-~ .’. /3 = 45+~/4
:~as been plotted on Figure ~8, B. For each degree of changein v., ~ changes
°.
by one quarter of a degree. Theyare only equal whenboth are 6o
Variationof the ObtuseAngleof the Flap (8) ~with that of the Defect (y). It can
readily seen that 8 = i8o-7’/4 and this relationship is also plotted on Figure ~8, B.
\rith each degree changeof y, 8 varies by one quarter of a degree and the angles are
°.
rqual whenboth are ~44
Since fi fits = precisely only whenboth are 6o° and 8 fits y only whenboth are
~44, the angles of the flap cannot both equal their respective angles in oneconstruction.
};y plotting ~.//3 against y/8 in Figure I8, c it is possible to determinethat the angle
~es .,.vhich give the closest approximation
to perfect fit are ~ 5o°, y ~3o° ; /3 58°, 8 ~48°.
~ :~ion of the Angle (0) betweenthe Short Axis of the Defect (a) and that of
~.:!ap
,i,5.
°-/3/2.
0 can be readily shownto be equal to ~ 8o
Substituting/~ -- 45° + e/4 and symplifying
0 = I57½°- ~/8.
In other words0 changesat a rate 8 times slower than ~ and in the clinical range
:his is negligible.
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BRITISH
JOURNAL OF PLASTIC
SURGERY
Variation in Lengths of Short Axes’ of Flaps and Defect. Since the con:
madeup of isosceles triangles the same relationship exists betweena and b and!
ft. In other words a and b are equal whena is 6o°. As 0~ increases towards t
short axis of the defect (a) increases at a rate 4 times as rapid as (b).
EVER
sin
for grafti
donorsit
the skin
a&ieved,
skin is ri
~ually o
not alwa}
~st-auri,
:~r dora,’
~
0.sTs
o.~
~.o
~.s
FIG. I8. A, See appendix. B,
By plotting the acute angles of
the flap and the defect, ~ and fl
against one another a direct relationship
is shown. A similar
relationship is obtained plotting
the obtuse angles 7 and 8 against
one another. C, If the ratio of
the acute angles one to the other,
oqfl is plotted against the ratio of
the obtuse angles y/8 the value
at which these ratios are equal,
and therefore at which the angles
are most congruent,
can be
obtained.
:-’.’-:..7
c
REFERENCES
BORGHOUTS,
J. M. H. M. (x964)- Surgical treatment of basal-cell carcinoma and
cell carcinoma of the skin. Archivum Chirurgicum Neerlandicum, x6, I9-3o.
DUFOURMENTEL,
C. (I962). Le fermeture des pertes de substance cutan6e limit&s
lambeau de rotation en L pour losange " dit " LLL ". Annales de Chirut
7, 6~-66.
DUFOURMENTEL,
C. (t963). An L-shaped flap for lozenge-shaped defects. Transactions
the Third International
Congress of Plastic Surgery, p. 772. Amsterdam:
Medical Foundation.
GIBSON, T.,
STARK, H. and EVANS,J. H. (~969). Directional
variations
of humanskin in vivo. ffournal of Biomechanics, ~, 2oi-2o
4.
GIBSON,T., STARK, H. and KENEDI, R. M. (~97~)- The significance
of Langer’s
Transactions of the Fifth International Congress of Plastic and Reconstructive
p. ~2~3. Melbourne : Butterworths.
LIMBERG,
A. A. (~946). Mathematical principles of local plastic procedures on the
of the human body. Leningrad : Medgis.
LIMBERG,A. A. (~966). Design of local flaps. In " Modern Trends in Plastic Surgery
Second Edition, ed. by Gibson, T. London : Butterworths.
LIMBERG,
A. A. (~967). Planimetrie und Stereometrie der Hautplastik. Jena
Fischer Verlag.
~::G. I.
~ post.
:--4 inade