Volume 73, No.7: 2021 Siriraj Medical Journal
https://he02.tci-thaijo.org/index.php/sirirajmedj/index
462
Nutthawut Akaranuchat, M.D.
Division of Plastic Surgery, Department of Surgery, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok 10700, ailand.
Lower Extremity Reconstruction with Vascularized
Free-Tissue Transfer: 20 Years of Experience in
the Faculty of Medicine Siriraj Hospital, Mahidol
University, Bangkok, Thailand
ABSTRACT
Objective: e reconstruction of extensive so-tissue defects in the lower extremity still poses a great challenge
to plastic and reconstructive surgeons. e ideal approach is to achieve a proper so-tissue coverage with a well-
vascularized ap, which results in a durable weight-bearing surface and permits normal joint motion. is study
aims to retrospectively analyze the outcomes of lower-extremity reconstruction with vascularized free-tissue transfer
performed at our plastic surgery division.
Materials and Methods: A retrospective chart review was performed regarding 58 patients with defects in the lower
extremity which were reconstructed with vascularized free-tissue transfers between 2000 and 2019. Forty-four of
the patients were male, and 14 were female. e mean age was 44.4 years (range: 6-89 years). e most common
indication for free-ap surgery was a secondary reconstruction aer tumor eradication (23 cases, 39.7%), and 84.8%
of the defects were exposed bare bones, tendons, or joints.
Results: In our 58 reviewed cases, the foot was the most common area requiring reconstruction with a free ap
(68.9%), and the mean defect size was 12.5 x 8.1 cm. e most commonly used free ap was the Anterolateral thigh
free ap (39.7%), followed by the Gracilis free ap (29.3%), and the Supercial circumex iliac artery-perforator
free ap (10.4%). e recipient vessels most frequently used were posterior tibialis vessels (53.4%). e overall
ap-survival rate was 75.9%, though there was an increased survival rate of up to 85.7% in the last ve years of the
period studied. e ap-salvage rate was 40.9%, and arterial thrombosis was the major cause of ap loss (50%).
Factors associated with free-ap failure were re-exploration and free ap surgery aer tumor or cancer eradication.
e most common post-operative complication was ap-wound dehiscence (10.3%). Two patients received a ap
correction due to bulkiness, and three had recurrence of ulceration.
Conclusion: Microvascular free-tissue transfers for lower- extremity-defect reconstructions are reliable and valuable
as a surgical technique. In 20 years of experience, we’ve had an overall ap survival rate of 75.9%. Factors associated
with free-ap failure were re-exploration and free ap surgery aer tumor or cancer eradication. And our ap of
choice was the Anterolateral thigh free ap.
Keywords: Lower extremity reconstruction; foot reconstruction; free ap; microsurgery; ap surgery (Siriraj Med
J 2021; 73: 462-470)
Corresponding author: Nutthawut Akaranuchat
E-mail: nutthawut.aka@mahidol.ac.th, nutthawut.joe@gmail.com
Received 23 November 2020 Revised 17 March 2021 Accepted 19 March 2021
ORCID ID: https://orcid.org/0000-0003-1798-8484
http://dx.doi.org/10.33192/Smj.2021.60
Akaranuchat.
Volume 73, No.7: 2021 Siriraj Medical Journal
https://he02.tci-thaijo.org/index.php/sirirajmedj/index
463
Original Article
SMJ
INTRODUCTION
Microvascular free-tissue transfers have become the
preferred reconstructive technique to manage complex
wounds and surgical defects aer an ablative procedure,
as the result of trauma. It is also the preferred technique
to deal with special-requirements situations such as
facial reanimation with a functioning muscle transfer in
facial-palsy patients. ere have been numerous clinical
reports on free-tissue transfer since the microvascular
technique was introduced in the early 1960s.
1-5
Previous data
demonstrate that microvascular free-tissue transfers allow
for reliable, single-stage, and immediate reconstruction
involving more complex defects from various etiologies.
6-17
Many case series have also reported a high ap-success
rate.
To date, reconstruction of extensive so-tissue
defects in the lower extremity still poses a great challenge
to reconstructive surgeons. A defect on the lower limb
will require some form of reconstruction in the majority
of cases. Also, permanent scar formation aer tight
closure or aer skin graing or inadequate local ap
use can result in pain and unstable wounds when a
person is bearing weight. us, the ideal approach to
treating a lower-limb defect is to achieve proper so-
tissue coverage with a well-vascularized ap, which
results in a durable weight-bearing surface and permits
normal ankle motion.
18
ere is no debate that only free
aps can cover extensive so tissue defects and provide
satisfactory functional outcomes without amputation.
19,20
At our institute, we started performing free-ap
reconstruction for defects in the lower extremities in1992,
but we had not collected the data nor had we evaluated
the nal outcomes aer surgery. is study aims to
retrospectively analyze the outcomes of lower-extremity
reconstruction with vascularized free-tissue transfer
performed at the Division of Plastic Surgery, Department
of Surgery, Faculty of Medicine Siriraj Hospital, Mahidol
University.
MATERIALS AND METHODS
A retrospective chart review was conducted regarding
all patients who underwent free-ap surgery for lower-
extremity defect reconstruction at the Division of Plastic
Surgery, Department of Surgery, Faculty of Medicine Siriraj
Hospital from January, 2000 to December, 2019. e age,
gender, underlying disease, other risk factors (smoking,
obesity, etc.), American Society of Anesthesiologists
(ASA) classication, indication for surgery, location of
defect, type of ap, operative time, inow and outow
vessels, type of anastomosis, vein-gra usage, ischemic
time, length of hospital stay, length of intensive-unit
stay, ap-success rate, re-exploration surgery, salvage
rate, and perioperative complications of all the patients
were recorded. ese data were collected in a database
and were available for statistical analysis.
Data assessment
e total operative time was dened as the time
between the rst incision and the wound closure. e
ischemic time was dened as the time from the transection
of the vascular pedicle to a complete arterial anastomosis
and then the release of the vascular clamp. e ap-success
rate was dened as complete ap viability or partial ap
loss that still achieved the primary indication of surgery.
18
Complications were divided between ap- related and
general complications.
Statistical analysis of the data was performed using
the Statistical Package for the Social Sciences (SPSS). e
chi-square and Fisher’s exact test were used to statistically
compare variables that inuence the ap-success rate
and perioperative complications. A p-value of 0.05 or
less was regarded as statistically signicant.
RESULTS
Between January 2000 and December 2019, 58
microvascular free-tissue transfers for lower-extremity
reconstruction were performed to cover and/or reconstruct
various kinds of defects and diseases. ere were 44
men and 14 women ranging in age from 6 to 89 years
(mean: 44.4 years). Most of the cases involved a body
mass index (BMI) from 18.5-22.9 kg/m
2
(32.7%). Ten of
the 58 patients had underlying type 2 diabetic mellitus.
e three most common areas in the lower extremity
that needed reconstruction with a free ap were 1: a
foot (40 of 58, 68.9%), 2: a leg (14 of 58, 24.1%) and 3:
an ankle (5 of 58, 8.6%). Also, the plantar hind foot was
the most common area of the foot that needed coverage
(18 0f 58, 31.1%). Among the 58 patients, there were
23 defects (39.7%) caused from tumor eradication, 19
defects (32.8%) due to trauma, and 8 defects (13.8%)
resulting from post-operative debridement due to severe
so-tissue infection. Fiy-ve of the 58 cases (84.8%)
were defects that exposed bare bones, bare tendons, or
joints.
Seventy percent of the defects were between 5-15 cm.
(41 of 58, 70.7%); the mean defect size was 12.5 x 8.1 cm.
(a range from 3-26 cm.). e three most common ap
types for reconstructing a lower-extremity defect were
the Anterolateral thigh (ALT) free ap (23 of 58, 39.7%),
followed by Gracilis free ap (17 of 58, 29.3%), and the
Supercial circumex iliac artery perforator (SCIP) free
ap (6 of 58, 10.4%). e recipient arteries frequently
Volume 73, No.7: 2021 Siriraj Medical Journal
https://he02.tci-thaijo.org/index.php/sirirajmedj/index
464
used for anastomosis were the posterior tibialis artery
(31 of 58, 53.4%), the anterior tibialis artery (11 of 58,
19%), and the dorsalis pedis artery (8 of 58, 13.8%). More
than 70% (45 of 58) of the cases were performed with
one artery and one vein anastomosis, and 75.9% (44 of
58) of the patients had an arterial anastomosis with the
end-to-end anastomotic technique (end to side, 24.1%).
Most of the cases resulted, primarily, in a closing of the
donor-site defect (42 of 58, 72.4%). (Table 1)
The mean duration of the total operative time
(including surgical resection) was 520 minutes (range:
330-960 minutes). e mean ap harvesting time was
76 minutes (range: 40-120 minutes). e mean ischemic
time was 59 minutes (range: 36-115 minutes). (Fig 1)
For post-operative outcomes, the overall ap-survival
rate was 75.9% (44 of 58 patients). Re-exploration for
anastomosis revisions was performed in 22 of 58 cases
(37.9%), with a aps-salvaging success rate of 40.9% (9 of 22
cases). e most common cause of ap revision was venous
congestion (11 of 22 cases, 50%), but the most common
cause of total ap failure was arterial thrombosis (7 of 14
cases, 50%). e recipient-site complications included
wound dehiscence (6 of 58 cases, 10.3%), surgical-site
infection (4 of 58 cases, 6.9%), and skin-gra loss (4 of
58 cases, 6.9%). Donor-site complications were found
in 8.6% of patients, and the most common complication
was wound dehiscence (2 of 58 cases, 3.5%). (Table 2)
Due to advances in microsurgical techniques and
the better quality of microscopes and other instruments,
the outcomes of lower-extremity reconstruction were
signicantly better than previous outcomes. In our
institute, the overall free-ap survival rate rose from 66.7%
(2000-2014) to 85.7% (2015-2019). Some microsurgeons
have performed a more sophisticated ap to serve the
specic requirements of the patient with the aim of
restoring both the function and the appearance. (Table 4)
DISCUSSION
A major development in the reconstruction of
defects in various locations was the introduction of
free vascularized tissue transfer in the 1960s and 1970s,
which enabled primary reconstruction of more complex
and extensive defects. Our retrospective study presents
our sta’s experience in performing 58 microvascular
free-tissue transfers for lower- extremity reconstruction
over the last ten years, and it revealed a success rate
of 75.9%. e majority of defects were connected to
tumor ablative surgery and were between 5-15 cm. in the
largest dimension. A gracilis muscle free ap with skin
graing was frequently done in the past, but the ALT
free ap is our free ap of choice for lower-extremity
reconstruction, due to its harvesting in a very large ap
size, its long pedicle length, its low donor-site morbidity,
and its modications, such as enabling the inclusion of
fascia or muscle into the ap.
21
e re-exploration rate
in our series was 37.9%, with a salvage rate of 40.9%,
which is quite low when compared to results from other
studies.
22-24
In the last ve years, the ap-salvage rate has
signicantly improved, from 16.7% (2000-2014) to 70%
(2015-2019). (Tables 3 and 4)
Factors that inuence ap failure and associated
complications continue to be debated. Reported factors
related to ap failure are the pre-operative status of the
patient, his or her age, smoking, pre-operative radiation, ap
type, surgical expertise, use of a vein gra, operative time,
and re-exploration for anastomosis revision; however, we
still do not have sucient prospective data to denitively
identify all of the signicant causes. e factors related
to wound complications and general complications were
age, ASA class, diabetes mellitus, pre-operative radiation,
smoking, and alcohol consumption, but there remains
a lack of prospective data to denitively identify all of
the signicant causes.
7,14,25-29
For our report, re-explorative surgery and free ap
surgery aer tumor or cancer eradication were signicant
factors vis a vis total ap failure. e failure rate of free-
ap surgery signicantly decreased commensurate with
the increase in surgical expertise. (Tables 3 and 4)
CONCLUSION
Microvascular free-tissue transfers are reliable and
valuable as a surgical technique in achieving successful
lower- extremity defect reconstructions. At our institute,
we began performing free-ap reconstruction for defects
in the lower extremities in 1992. For the past 20 years,
the overall ap-survival rate was 75.9% (44 of 58 cases);
the re-exploration rate was 37.9% (22 of 58 cases); and
the rate of successfully salvaging aps was 40.9% (9 of
22 cases). e anterolateral thigh free ap was the ap of
choice in our lower-extremity defect reconstruction. e
most commonly used recipient vessels were the posterior
tibialis artery and vein. In our institute’s experience,
the key factors associated with lower extremity free-
ap failure were re-exploration and free ap surgery
aer tumor or cancer eradication. Finally, this study
presents 20 years of experience and surgical outcomes in
lower-extremity defect reconstruction with vascularized
free-tissue transfers at the Division of Plastic Surgery,
Department of Surgery, Faculty of Medicine Siriraj
Hospital, Mahidol University. ese results present a
current baseline for lower-extremity free-ap surgery
to which future advances in technique and practice may
be compared.
Akaranuchat.
Volume 73, No.7: 2021 Siriraj Medical Journal
https://he02.tci-thaijo.org/index.php/sirirajmedj/index
465
Original Article
SMJ
TABLE 1. Patients’ demographic and clinical data.
Characteristics
Number of patients 58
Mean age, year (range) 44.4 (6-89)
Sex, male (%): female (%) 44 (75.9%): 14 (24.1%)
Body mass index, BMI (%)
<18.5 11 / 58 (19.0%)
18.5 - 22.9 19 / 58 (32.7%)
23.0 - 24.9 12 / 58 (20.7%)
25.0 - 29.9 15 / 58 (25.9%)
30 - 40 1 / 58 (1.7%)
40.1 - 50 no
>50 no
ASA classication
Class I 38
Class II 9
Class III 10
Class IV 1
Underlying disease
Diabetic mellitus no. (%) 10 / 58 (17.2%)
Smoking no. (%) 7 / 58 (12.1%)
Peripheral arterial disease no. (%) 5 / 58 (8.6%)
Hypertension no. (%) 8 / 58 (13.8%)
Dyslipidemia no. (%) 3 / 58 (5.2%)
Paraparesis or paraplegia 2 / 58 (3.4%)
Hemiparesis or hemiplegia 1 / 58 (1.7%)
Tumor or cancer 2 / 58 (3.4%)
Chronic renal failure 1 / 58 (1.7%)
Defect site no. (%)
Thigh 1 / 58 (1.7%)
Knee 3 / 58 (5.2%)
Popliteal fossa no
Leg 14/58 (24.1%)
Proximal third leg no
Middle third leg 1 / 58 (1.7%)
Distal third leg 2 / 58 (3.4%)
Proximal and middle third leg no
Middle and distal third leg 3 / 58 (5.2%)
Proximal, Middle and distal third leg 3 / 58 (5.2%)
Ankle 5 / 58 (8.6%)
Foot 40/58 (68.9%)
Dorsal of foot 7 / 58 (12.1%)
Plantar forefoot 4 / 58 (6.9%)
Plantar midfoot 2 / 58 (3.4%)
Plantar hindfoot 18 / 58 (31.1%)
Plantar forefoot and midfoot 3 / 58 (5.2%)
Plantar midfoot and hindfoot 5 / 58 (8.6%)
Plantar forefoot, midfoot and hindfoot 1 / 58 (1.7%)
Volume 73, No.7: 2021 Siriraj Medical Journal
https://he02.tci-thaijo.org/index.php/sirirajmedj/index
466
Defect size no. (%)
Small defect (<5 cm) 3 / 58 (5.2%)
Medium defect (5-10 cm) 22 / 58 (37.9%)
Large defect (10.1-15 cm) 19 / 58 (32.8%)
Very large defect (15.1-20 cm) 8 / 58 (13.8%)
Giant defect (>20 cm) 6 / 58 (10.3%)
Etiology no. (%)
Trauma 19 / 58 (32.8%)
Tumor or cancer eradication 23 / 58 (39.7%)
Infection 8 / 58 (13.8%)
Ischemic ulcer 2 / 58 (3.4%)
Venous ulcer no
Diabetic ulcer or neuropathic ulcer 4 / 58 (6.9%)
Irradiation no
Unstable scarring 2 / 58 (3.4%)
Exposure to bone, tendon, or joint no. (%) 55 / 58 (84.8%)
Mean defect size (Length x width, cm) 12.5 x 8.1 cm (Range 3-26 cm)
Flap source artery no. (%)
Branch of lateral circumex femoral artery 3 / 58 (5.2%)
Popliteal artery no
Posterior tibialis artery 31 / 58 (53.4%)
Medial plantar artery 3 / 58 (5.2%)
Anterior tibialis artery 11 / 58 (19.0%)
Dorsalis pedis artery 8 / 58 (13.8%)
Peroneal artery 1 / 58 (1.7%)
Lateral supramalleolar artery 1 / 58 (1.7%)
Number of anastomosis no. (%)
1 artery:1 vein 45 / 58 (77.6%)
1 artery:2 vein 13 / 58 (22.4%)
Type of arterial anastomosis no. (%)
End to end 44 / 58 (75.9%)
End to side 14 / 58 (24.1%)
Free ap no (%)
ALT free ap 23 / 58 (39.7)
VL free ap 1 / 58 (1.7%)
Latissimus dorsi free ap 3 / 58 (5.2%)
Gracilis free ap 17 / 58 (29.3)
MSAP free ap 4 / 58 (6.9%)
SCIP free ap 6 / 58 (10.4%)
Radial forearm free ap 1 / 58 (1.7%)
Parascapular free ap 1 / 58 (1.7%)
Internal oblique muscle free ap 1 / 58 (1.7%)
Temporoparietal fascial free ap 1 / 58 (1.7%)
Flap composition no. (%)
Fasciocutaneous ap 34 / 58 (58.6%)
Muscle ap 18 / 58 (31.1%)
Musculocutaneous ap 4 / 58 (6.9%)
Fascial ap 1 / 58 (1.7%)
Osteocutaneous ap 1 / 58 (1.7%)
Donor-site closure no (%)
Primary closure 42 / 58 (72.4%)
STSG 16 / 58 (27.6%)
Abbreviations: ASA = American Society of Anesthesiologists; ALT = Anterolateral thigh; VL = Vastus lateralis; MSAP = Medial sural artery
perforator; SCIP = Supercial circumex iliac artery perforator; STSG = Split-thickness skin gra
Akaranuchat.
Volume 73, No.7: 2021 Siriraj Medical Journal
https://he02.tci-thaijo.org/index.php/sirirajmedj/index
467
Original Article
SMJ
Fig 1. Le plantar midfoot defect aer tumor eradication.
e defect was reconstructed with supercial circumex
iliac artery perforator free ap which harvested from le
groin area. Donor site defect was closed primarily. Inset
ap was done and the microvascular anastomosis was
performed with lateral plantar vessels.
TABLE 2. Post-operative surgical outcomes.
Flap survival no. (%) 44 / 58 (75.9%)
Flap loss no. (%)
Partial loss no. (%) 11 / 58 (19.0%)
Complete loss no. (%) 14 / 58 (24.1%)
Arterial thrombosis no. (%) 7 / 14 (50.0%)
Venous thrombosis no. (%) 6 / 14 (42.9%)
Hypercoagulable stage no. (%) 1 / 14 (7.1%)
Flap revision no. (%) 22 / 58 (37.9%)
Arterial insufciency no. (%) 10 / 22 (45.5%)
Venous congestion no. (%) 11 / 22 (50%)
Bleeding hematoma 1 / 22 (4.5%)
Flap salvage no. (%) 9 / 22 (40.9%)
Recipient site complication no. (%) 19 / 58 (32.8%)
Infection no. (%) 4 / 58 (6.9%)
Dehiscend wound no. (%) 6 / 58 (10.3%)
STSG loss no. (%) 4 / 58 (6.9%)
Hematoma no. (%) 2 / 58 (3.5%)
Seroma no. (%) no
Donor site complication no. (%) 5 / 58 (8.6%)
Infection no. (%) 1 / 58 (1.7%)
Dehiscend wound no. (%) 2 / 58 (3.5%)
STSG loss no. (%) 1 / 58 (1.7%)
Hematoma no. (%) no
Seroma no. (%) 1 / 58 (1.7%)
Flap correction
Debulging no. (%) 2 / 44 (4.5%)
Recurrent ulcer no. (%) 3 / 44 (6.8%)
Volume 73, No.7: 2021 Siriraj Medical Journal
https://he02.tci-thaijo.org/index.php/sirirajmedj/index
468
TABLE 3. Data comparisons between the group of ap success and ap failure.
Comparative data Flap success (%) Flap failure (%) p-value
Case 44 (75.9%) 14 (24.1%) 0.165
Year 2000-2014 20 (66.7%) 10 (33.3%)
Year 2015-2019 24 (85.7%) 4 (14.3%)
Sex 0.931
Male 33 (75%) 11(25%)
Female 11(78.6%) 3 (21.4%)
ASA classication 0.913
Class I 29 (76.3%) 9 (23.7%)
Class II 7 (77.8%) 2 (22.2%)
Class III 7 (70%) 3 (30%)
Class IV 1 (100%) 0 (0%)
Cause
Trauma 17 (89.5%) 2 (10.5%) 0.173
Tumor or cancer eradication 13 (56.5%) 10 (43.5%) 0.013*
Infection 7 (87.5%) 1 (12.5%) 0.701
Ischemic ulcer 2 (100%) 0 (0%) 0.977
Diabetic ulcer or Neuropathic ulcer 3 (75%) 1 (25%) 0.573
Unstable scarring 2 (100%) 0 (0%) 0.977
Underlying disease
Diabetic mellitus no. (%) 7 (70%) 3 (30%) 0.944
Smoking no. (%) 6 (85.7%) 1 (14.3%) 0.858
Peripheral arterial disease no. (%) 4 (80%) 1 (20%) 0.749
Hypertension no. (%) 8 (100&) 0 (0%) 0.203
Dyslipidemia no. (%) 3 (100%) 0 (0%) 0.756
Paraparesis or paraplegia 2 (100%) 0 (0%) 0.977
Hemiparesis or hemiplegia 1 (100%) 0 (0%) 0.542