Soft Tissue Defects of Lower One Third of Leg: Options for Flap Coverage

INTRODUCTION
Lower one third of the leg has a special anatomy,
makes the coverage of soft tissue defects a difficult
problem [1]. This area is deficient from muscles
and vascularity of tissues is minimal in comparison
with other areas of the body. The skin and superficial
fascia on the tibia are thin stretched on the
bone, so the bones of the lower third are more
vulnerable to injury, and exposure [2,3].
221
All these factors preclude to loss of soft tissue
once traumatized, with exposure of bone, tendons,
plate and screws or even ankle joint. Soft tissue
repair of this defect may be with local flap, fascioctaneous
pedicled flap, or free tissue transfer [4,5].
As regard flap with random pattern territory in
lower part of leg proved to be ineffective, because
these flaps are usually small in dimensions, and
range of mobilization of the flap is limited [6].
With more complexity of the injuries, more
complex procedures for reconstruction will be
necessary [7,8].
Three principle vascular systems supply the
leg, posterior tibial, anterior tibial, and peroneal,
they pass in closed compartment, with less significant
communication between them. Based on this
vascular territory, a lot of perforator flaps can be
elevated. But in degloving injuries these perforators
may be lost and cannot be used [9].
Free tissue transfer is recommended as the best
solution for soft tissue defects in distal lower leg
[10]. Reconstruction with free flap provides healthy
tissue for reconstruction, but many times leads to
sacrifice of one of the major vessels of leg [11].
Perforator flap concept entail a part of skin
associated or not with subcutaneous fascia, supplied
by a branch from main arteries. This branch (perforator),
may pass through muscle (musculocutaneous
perforator flaps), or (septocutaneous
perforator flap). After the wide application of these
perforator flaps, the concept of considering free
flap the basic tool for soft tissue reconstruction of
lower leg decreased [8,12-16].
In many cases local tissues are so severely
damaged that there are no possibilities for local
flaps harvesting or free flaps transfer due to the
absence of available recipient vessels [17]. The
cross-leg flap was described by Hamilton 1854,
after that it was used for soft tissue coverage in
the distal leg, After diffusion of microsurgery since
1970, cross-leg flaps for lower limb wound coverage
have been replaced by free flaps, but in specific
conditions the cross-leg flap still considered a
simple and effective alternative [18].
In some clinical situations in which local fasciocutaneous
and myocutaneous flaps are not available.
Occasionally, a free flap may also have failed
because of technical errors or damaged vasculature.
In these situations, a cross-leg flap is the best
choice. The inclusion of fascia in the flap makes
length-to-breadth ratio 3: 1 perfectly safe. This
allows much greater area of skin to be transferred
with much more freedom of leg position. The flap
provided stable coverage for different defects with
few complications [19].
In this study we will compare the 3 flap reconstruction
commonly used for coverage of lower
one third leg; free LD muscle flap, cross leg flap
and medial/lateral septocutaneous perforator flaps.
We compare these different methods as regard the
hospital stay, operative time, flap size, flap failure,
associated complications, and secondary procedures.
PATIENTS AND METHODS
In the period from January 2014 to March 2016,
a total number of thirty three patients (27 males
and 6 females) presented with lower limb soft
tissue defects (19 in right leg and 14 left leg). The
soft tissue defects in twenty five cases were caused
by rood traffic accident (RTA), run over accident
in six patients, street driller machine in one case
and falling from height in one case.
The soft tissue defect ranged from most of the
leg; lateral side of the ankle (7 cases), distal one
third of leg (9 cases), medial side of distal leg,
ankle and foot (4 cases), dorsum of the foot and
ankle (3 cases), volar side of distal leg (6 cases),
lateral side of distal leg (3 cases), Around ankle
and foot (1 case).
The Patients were divided according to the
reconstructive procedure done into three groups:
Free latissmus dorsi flap (group I), cross leg flap
(group II) and medial/lateral septocutaenous perforator
flap (group III).
In group I (Free latissmus dorsi flap), eleven
patients (9 male and 2 females), their age ranged
from 7 to 60 years (29.91±12.89). Defect size
ranged from 6X13 to 14X 30Cm. All patients
222 Vol. 42, No. 2 / Soft Tissue Defects of Lower One Third of Leg
received blood transfusion intraoperative and three
of them received also postoperative blood transfusion,
the blood transfusion volume ranged from
500CC to 3000CC (1545.45±690.59CC).
In group II (Cross leg flap), thirteen patients
(12 male and 1 females), their age ranged from 6
to 60 years (30.38±18.25). Defect size ranged from
7X11 to 10X15Cm. All patients did not need any
blood transfusion intraoperative or postoperative.
In group III (Medial/lateral septocutaenous
perforator flap), nine patients (6 male and 3 females),
their age ranged from 4 to 40 years
(23.11±12.05). Defect size ranged from 4X5 to
8X14Cm. All patients did not need any blood
transfusion intraoperative or postoperative.
Operative procedures:
All patients were admitted to emergency unit.
Stabilization and exclusion of other life endanger
comorbid emergencies.
Patients were examined by orthopedic, vascular
and plastic surgeons as multidisciplinary team.
Fracture fixation as planned by orthopedic surgeons;
most cases have external fixator done.
Ensure good distal perfusion to all cases by vascular
surgeon and debridement done at this stage plus
fasciotomy if needed. After 48 hours another debridement
and dressing and at this time planning
for covering done.
The choice of covering method depend on many
factors; size of the defect, the defect level, associated
skin degloving injury, availability of nearby
perforator detected by Doppler, and intact major
vascular bundles. The patient general condition
(associated medical condition of the patient, smoker
or nonsmoker). The availability of microvasculr
free flap perquisites; two teams, operating microscope,
and long operative procedure requirement
(OR time, anaethesia). All these factors affected
the covering methods.
Routine work up, laboratory investigation,
needed X-rays, colored Doppler, CT angiography
if needed, and blood cross matching for all cases.
Technique:
Group I (free LD flap):
Tow team worked simultaneously, one team
started preparing for the recipient vessel away
from trauma zone one artery, and two veins prepared;
one vena commitant and one subcutaneous
vein. The other team started LD muscle elevation
and preparation. Once recipient vessel with good
arterial flow was detected, the LD muscle flap was
Egypt, J. Plast. Reconstr. Surg., July 2018 223
separated and microvascular anastomosis was
started under microscope; veins were anastomosed
first then the artery. The muscle flap was in sited
and tucked to the surrounding defect edge. Soft
drain under the flap was routine in all cases. Postoperative
flaps monitoring and IV heparin infusion
25 thousand units per 24 hours for 5 days. After 2
weeks all cases with viable flaps underwent split
thickness skin graft 2ry procedures.
Group II (crossed leg flap):
In this group the flap size and dimensions was
planned on the medial posterior tibial septal perforator
about 1-2cm from the medial border of the
tibia in its middle third. Flaps are raised as fasciocutaneous
flaps involving not only posterolateral
but also anterior compartmental tissue if needed.
Flaps were in-sited covering most of the defect
(about 75% of the defect) at time of surgery, the
position was fixed with external fixator that was
applied with orthopedic surgeons, and the donor
site was covered with STSG harvested from the
contralateral thigh. Tie over applied over graft in
all case. After 3 to 4 weeks flaps separation done,
enough skin was taken to cover the remaining
defect.
Group III (medial/lateral septocutaneous perforator):
In this group, all patients are without history
of degloving injury of the leg skin, a hand-held
Doppler examination of the area were done to
detect perforator/perforators with good signal near
the defect, proposed flap was designed over the
leg skin keeping in mind arc of rotation, pivot
points from the defect in flap measurements.
Under loupe magnification through an exploratory
incision, dissection done in the subfascial
plan, the pre-detected perforators were explored
and also other perforators were dissected. The
largest nearer perforator was selected and the flap
was readjusted over the selected perforator. Perforators
were dissected from the surrounding deep
fascia all around for few centimeters. The perforator
flaps can be trans-positioned from 90 degree up
to 180 degree as propeller flap. Traction, twisting,
or kinking of the pedicle should be avoided. Soft
drains are kept under the flap for 48 hours.
The donor site was covered by split thickness
skin graft harvested from the contralateral thigh
then tie over dressing was applied in all cases.
Below knee POP slab applied to stabilize the foot
and leg.
Postoperative flaps were monitored continuously,
good hydration, leg elevations and antibiotics.
Site and the flap covering the defect 3 month postoperative.
Statistical analysis:
Data were analyzed by Statistical Package of
Social Science (SPSS), software version 22.0 (SPSS
Inc., 2013). Continuous data were expressed as
Mean ± SD, while the nominal data were presented
by the frequency and percentage.
The one-way analysis of variance (ANOVA):
Is used to determine whether there are any significant
differences between the means of three independent
groups. Least significance difference
(LSD): It is one of the post hoc tests. It is used for
multiple comparisons between groups. It was calculated
at different probability values. p-value
<0.05 considered significant.
RESULTS
There was no significant deference in patients'
age among the three operated groups (p>0.05).
The time relapsed from injury to surgery was
significantly shorter in group I (8.91±4.55 days)
than those of group II (20.46±10.88, p<0.01) and
group III (19.22±11.72, p<0.05), but no significant
deference could be detected between group II and
group III (p>0.05). The operation time (hours) was
significantly longer (p<0.001) in group I (6.55±
1.40) than those of group II (2.46±0.35) and group
III (2.06±0.25), however, no significant deference
could be detected between group II and group III
(p>0.05).
Regarding flap size (Cm2), free latissmus dorsi
flap (group I) had a significant wider size (164.73
±88.59) when compared with the size of cross leg
flap (group II) (107.00±22.24, p<0.05) and medial
septocutaenous perforator flap (group III) (50.78
±26.21, p<0.001), moreover, group II had a significant
wider size than that of group III (p<0.05).
The wound healing time (weeks) was significantly
rapid in group III (2.00±1.69) when compared to
that of group I (4.32±0.96) and group II (4.88±
1.66) (p<0.001), but no significant difference could
be detected between group I and group II concerning
healing time (p>0.05).
The period of hospital stay (days) and followup
period (months) were significantly shorter in
group III (3.33±2.69 day, 10.77±5.85 month) when
compared to that of group I (22.90±5.59, 16.64±
7.53) and group II (31.00±8.19, 15.62±4.15), however,
no significant difference could be detected
between group I and group II regarding the period
of hospital stay or follow-up period (p>0.05).
Secondary procedure in group I had done in all
cases (100%) (10 patients operated by split thickness
skin graft and Cross leg flap for one patient).
In group II all patients obligatory had a flap separation
after 3 weeks, moreover, one case needed
further defatting and other had Debridement, reinsertion
of flap. In group III: Only one case (9.09%)
needed split thickness skin graft.
Donor site morbidity in group I (45.45% of
cases); 3 cases got seroma, one needed debridement
then reinsertion and one case got ugly scar. In
224 Vol. 42, No. 2 / Soft Tissue Defects of Lower One Third of Leg
group II: Only one case got ugly scar (7.5%).
However, group III had no donor site morbidity
(0%).
Complications or failure in group I occurred in
7 cases (63.63%): Marginal flap necrosis in 2 cases,
Collection under the flap in 4 cases and Hematoma
under the flap in 1 case. In group II: 4 cases
(30.76%) were complicated by Partial flap dehiscence
(3 cases) and Bulky flap (one case). In group
III: 2 cases (22.22%) were complicated by Partial
distal flap necrosis in one patient and sinus pouring
seropurrulent in another patient who was treated
by dressing and antibiotics.
Table (1): Statistical analysis of age (years), flap size (Cm2), postoperative DASH score, cosmetic evaluation score and followup
period (month) between the three operated groups (free latissmus dorsi flap, cross leg flap and medial/lateral
septocutaenous perforator flap).
Age (year):
Mean ± SD
Time from injury to surgery/days:
Mean ± SD
p-value
Operation time/hrs:
Mean ± SD
p-value
Flap size (cm2):
Mean ± SD
p-value
Healing time/weeks:
Mean ± SD
p-value
Hospital stay/days:
Mean ± SD
p-value
Follow-up:
Mean ± SD
p-value
Cosmetic evaluation:
Mean ± SD
p-value
Patient satisfaction:
Mean ± SD
p-value
Groups
Parameters
29.91±12.89
8.91±4.55
6.55±1.40
164.73±88.59
4.32±0.96
22.90±5.59
16.64±7.53
6.56±0.67
5.69±0.49
Free latissmus dorsi flap
(group I)
30.38±18.25
0.813a
20.46±10.88
0.006a
2.46±0.35
<0.001a
107.00±22.24
0.015a
4.88±1.66
0.264
31.00±8.19
0.67a
15.62±4.15
0.676a
5.56±0.65
<0.001a
6.65±0.36
0.66a
Cross leg flap
(group II)
23.11±12.05
0.399a, 0.275b
19.22±11.72
0.022a, 0.766b
2.06±0.25
<0.001a, 0.286b
50.78 ±26.21
<0.001a, 0.025b
2.00±1.69
<0.001a, <0.001b
3.33±2.69
<0.001a, <0.001b
10.77±5.85
0.035a, 0.05b
6.71±0.31
0.582a, <0.001b
5.99±0.76
0.007a, 0.002b
Medial/lateral septocutaenous
perforator flap (group III)
a = Versus group A. b = Versus group B.
Egypt, J. Plast. Reconstr. Surg., July 2018 225
Fig. (1): Pre operative soft tissue defect of lower leg and exposed fixation plate (A), Elevated LD flap (B) and after
flap insetting in the soft tissue defect of lower leg (C).
Fig. (2): After Split thickness Theirsh graft on the LD flap (A &B), after healing of STTG (C&D).
Fig. (3): A preoperative soft tissue
defect of lower leg.
(A)
(B) (C)
(A)
(B) (C) (D)
226 Vol. 42, No. 2 / Soft Tissue Defects of Lower One Third of Leg
Fig. (4): Elevation of the
cross leg flap (A), and Insetting
of the cross leg flap (B).
Fig. (5): After separation of the cross leg flap
recipient site (A) and donor site (B).
Fig. (6): Peroneal septal perforator preoperative drawing (A),
peroneal septal perforator elevation (B&C).
(A) (B)
(A) (B)
(A)
(B)
(C)
Egypt, J. Plast. Reconstr. Surg., July 2018 227
Fig. (7): Peroneal septal perforator in-setting (A&B) and
Peroneal septal perforator flap skin grafting (C).
Fig. (8): Peroneal septal perforator flap after healing (A&B).
Fig. (9): Medial septal perforator preoperative defect (A) and
Medial septal perforator flap drawing (B).
Fig. (10): Medial septal perforator flap elevation.
(A)
(C)
(B)
(A) (B)
(A)
(B)
DISCUSSION
Lower one third of the leg is common to be
injured. At this level most of soft tissue covering
become insufficient even with moderate trauma
the bone and deeper structures become exposed.
The surrounding tissues are deficient enough to
cover large defects; smaller to moderate size defect
could be covered by using surrounding tissue flaps
that depend on medial or lateral perforator. Perforator
flap could be done supposed that no degloving
skin injury.
Most of the patients in this study were males
with mean age 27 years in all groups; the most
common cause of the trauma was road traffic
accidents. Most of the defects were at the distal
one third of legs. The defect size in this study was
ranged from 6x13cm to 14x30cm in group I,
7x11cm to 10x15cm in group II, and 4x5cm to
8x14cm in group III.
In this study flap size (Cm2) the free latissmus
dorsi flap (group I) had a significant wider size
(164.73±88.59) when compared with the size of
cross leg flap (group II) (107.00±22.24, p<0.05)
and medial septocutaenous perforator flap (group
III) (50.78 ±26.21, p<0.001), moreover, group II
had a significant wider size than that of group III
(p<0.05).
In spite of the different available options, free
tissue transfer remains as one of important options
for coverage of lower third leg defects. As free
228 Vol. 42, No. 2 / Soft Tissue Defects of Lower One Third of Leg
tissue transfer have advantages as it can cover
large defect, it can be used in acute trauma by
choosing recipient vessels away from the zone of
injury, there is no additional scarring in the surrounding
area, as what happen when local flaps
are used, it has a higher success rate (could be as
high as 98%) if planned well and finally according
to the need of the defect the flap to be chosen,
muscle flaps for cavities filling and skin flaps when
surface defects are to be covered or there is a need
for secondary procedures like bone grafting [1].
Regarding the mean time (in days) between
trauma and definitive coverage in this study was
9 days in group I, 20 days in group II, and 19 days
in group III.
The challenge for the reconstructive surgeon
is to match the original tissue properties if joint
function and esthetic form are to be preserved.
Free tissue transfer has been the traditional reconstructive
modality in this region; however, microsurgical
skill, specialized equipment, and resources
required for these complex operations are not
commonly available outside of tertiary care centers.
Furthermore, tissue properties of some free flaps
may not be ideal matches to the thin, supple fasciocutaneous
tissue of the ankle region. Muscle flaps
are associated with a loss of function, albeit often
imperceptibly, as well as with inadequate reach in
the distal lower extremity [20,21].
Reconstruction with local fasciocutaneous flaps
is an ideal option because it provides the closest
Fig. (11): Medial septal perforator flap in-setting (A) and
medial septal perforator flap in-setting with skin
graft (B).
Fig. (12): Medial septal perforator 3 weeks postoperative.
(A)
(B)
Egypt, J. Plast. Reconstr. Surg., July 2018 229
match to lost tissue in terms of skin color, durability,
volume, and pliability. Local random pattern flaps
are unreliable because of limited flap dimensions,
a wide pedicle base restricting flap mobility, and
relatively poor tissue laxity. There is an upward
of 25% flap necrosis in single-stage distal lower
extremity reconstruction utilizing the most robust
random pattern flaps [22]. It is well known that the
free flap procedure needs a higher technical level
of surgical expertise and more complex surgery
[23,24].
Compared with a free flap, using a perforatorbased
propeller flap requires a simpler operation
and shorter operating times, and can be performed
without the staff expertise and complex logistical
setup [24].
The use of a fibula osteoseptocutaneous flap
provides good evidence of how peroneal artery
perforator-based propeller flaps are a better option
for skin harvesting of a larger area [25].
Furthermore, perforator-based propeller flaps
offer versatility in terms of providing different
shapes and sizes, and they can be easily retrieved
from other parts of the body for covering small
defects in the lower leg [13,26].
Most importantly, this procedure ensures blood
supply by avoiding the major blood vessels. In
particular, its greater rotation versatility allows an
easier distal lower leg soft tissue reconstruction.
Detailed examination of the perforator-based propeller
flap technique has shown it to be a highly
reliable and the preferred surgical option for treating
soft tissue defects of the lower leg [27,28].
It also provides a good cosmetic postoperative
appearance. The traditional fasciocutaneous flap
always has a skin bridge at the pedicle. Keeping
the skin bridge at the base of a peninsular flap may
in fact kink the pedicle, which might compromise
the vascular supply of the flap. This makes flap
rotation difficult and calls for the need to harvest
a bigger flap [29,30].
The propeller flap always needs a skeleton of
pedicle vessels, so that it can rotate freely from 0
to 180. Flap rotation will work successfully as long
as the pedicle does not become tight after the flap
rotation. Alternative local flaps are also used, such
as the distally-based sural flap or the distally-based
peroneus brevis flap [31,32].
Wounds that can to be covered by a peroneal
perforator-based pedicle propeller flap can also be
covered by both the distally based sural flap and
the distally-based peroneus brevis flap; and these
two flaps are easier to undertake surgically than
the propeller flap at the pedicles of the flaps
[31,32,33].
However, these two types of flaps produce 'dog
ears' at the pedicle after flap rotation. It is evident
that the bulky 'dog ears' of the traditional fasciocutaneous
flap is visually unappealing and if the
aesthetics of the leg are poor, then the operation
would need to be performed again, especially if
the ankle is distorted and wearing footwear is not
possible. In this case, cosmetic surgery may also
be necessary. Furthermore, application of the distally-
based sural flap would damage the nerve,
which then leads to sensation dysfunction [34,35].
In contrast, the peroneal perforator-based pedicle
propeller flap does not damage the nerve [26].
In terms of post-operative complications, such
as venous congestion, haematocele, infection, and
skin grafting necrosis at the donor-site, the rates
of these are similar for the distally-based sural
flap, the distally-based peroneus brevis flap and
the peroneal perforator-based pedicle propeller
flap [26,33,36-38].
There are a number of disadvantages associated
with using perforator-based propeller flaps. Unfortunately,
venous congestion cannot be totally avoided
during the propeller flap operation because the
walls of the perforator vessels are more delicate
compared with the perforator arterial wall and it
is difficult to control venous wall damage after the
180 rotation of the pedicle [39].
Venous congestion can give rise to necrosis at
the distal flap. After rotation of the flap, if the
pedicle is pulled tightly it will lead to venous
congestion. If the pedicle is not bared, the deep
fascia around the pedicle will compress the vessels
in the pedicle when the flap is rotated [40].
Venous congestion is one of the most difficult
problems to deal with and constitutes one of the
main reasons for flap necrosis [37,38].
A precise preoperative plan can reduce the rate
of venous congestion [41,42].
The performance of the flap relies on: (i) the
flap length; (ii) the pedicle size; and (iii) the rotation
angle [13].
Since Taylor [43] introduced the concept of
angiosomes, various techniques of perforator based
local flaps in the leg have been developed [44,45].
Perforators from the three main arteries in the
lower leg and found that those of the PTA were
distributed evenly compared to the other two arteries.
PTA perforators are found to be the largest of
the lower leg and easier to dissect compared to the
PAP. They are predominantly septocutaneous,
arising from within the intermuscular septum between
soleus and flexor hallucis longus [14,46].
Ozdemir et al. [46] also performed comprehensive
cadaver studies to conclude that distal lower
leg is suitable for PTAPF elevation because PTA
perforators are larger and concentrated in the lower
leg and ankle region which they categorized zone
I and II. Moreover, Jakubietz et al. [47] recently
described that the PTA perforator was most favorable
as source vessel due to its constant subfascial
directionality, which is almost always about 90~100
degrees. The PTA perforators are connected in an
axial network and this enables the surgeon to raise
large flaps reported up to 19x13cm. [49].
Cross-leg flaps have problem because of difficulties
in immobilization and position fixation of
the extremities from the time of initial coverage
to detachment. The use of external fixator for
immobilization facilitates many of these problems
and helps the use of cross-leg flaps in patients in
whom free flaps may not be optimal [9,50].
Hafeez et al. [51] conducted their study on 24
patients with defects over the lower half of the leg.
They covered these defects using a posterior tibial
artery perforator island flap harvested from the
medial aspect of the leg. The major etiology of
soft-tissue defect was road traffic accident, which
corresponds to our study.
For a long period of time cross-leg flaps were
the only reconstructive option for the difficult areas
of the distal leg and foot, with high success rates
and minimal morbidity in expert hands. Cross leg
flaps, however, are highly technique dependent,
which explains the variable success rates described
in the literature [18,52]. These flaps were described
as being handicapped by the inherent problems of
positioning and immobilization [53], because of
their short, thick and inextensible pedicles, awkward
postures and bulky external fixation devices
are invariably needed [54,55].
In comparison to one-stage reconstruction using
free flaps, cross-leg flaps require at least two
surgical stages. Moreover, they do not augment
the blood supply of the recipient defect. However,
despite the widespread use of microsurgery in
management of lower leg injuries, still the cross
230 Vol. 42, No. 2 / Soft Tissue Defects of Lower One Third of Leg
leg flaps have their role. However they have the
disadvantage of prolonged immobilization and
incidence of partial or total flap loss. Several
modifications were published to overcome this
incidence of failure by delaying the division of the
flap or incorporating fascial extension in the flap
[55,56].
In conclusion:
flap coverage for lower one third leg defect is
difficult question to answer, a lot of flaps could
be used each method has its pros and cons, perforator
flap is easy and versatile with learning curve
it can be used for small to moderate size defects,
cross leg flap remain as easy and versatile flap and
can be used as backup plan for other methods, free
LD flap provide large flap size used for large
defects.
Conflict of interests: The authors declare no
Conflict of interests.