3. Anatomy
The arterial basis for the sural flap is a branch
arising either from the popliteal artery or from the
lateral sural artery. From its origin, the artery
usually follows the course of the lateral sural
cutaneous nerve, reaching the overlying fascia
approximately 5 cm inferior to the popliteal crease.
The artery and nerve continue distally in a
subfascial course for a variable distance. Both
suprafascial and subfascial plexuses are supplied by
these class B fasciocutaneous vessels. The lesser
saphenous vein courses in a subcutaneous plane
between the two heads of the gastrocnemius
muscle. Paired venae comitantes accompany the
fasciocutaneous artery; these veins are
preferentially used to establish venous drainage for
the transplanted flap. The lesser saphenous vein is
usually not employed.
The lateral sural cutaneous nerve arises in the
popliteal fossa from the common peroneal nerve.
After giving rise to a communicating nerve, it
usually penetrates the deep fascia 5 to 10 cm distal
to the popliteal crease supplying the fascia and skin
of the lateral two thirds of the leg.
4. Arterial Anatomy
Dominant Pedicle Sural artery perforator
Regional Source Popliteal artery.
Length 3 cm.
Diameter 1.4 mm.
Location This pedicle descends from the popliteal fossa between the
heads of the gastrocnemius muscle and deep fascial layer and
courses inferiorly, superficial to the gastrocnemius muscle.
5. Arterial Anatomy
Minor Pedicle Perforators from the peroneal artery
Regional Source Peroneal artery.
Length 1 cm.
Diameter 1 mm.
Location Distal third of the leg
6. Arterial Anatomy
Minor Pedicle Neurocutaneous perforators from the vasa nervorum
of the sural nerve
Regional Source Sural artery.
Length 1 cm.
Diameter Greater than 1 mm.
Location The rich anastomotic vasa nervorum of the sural nerve
gives off neurocutaneous perforating vessels to the skin and the
fascia overlying it.
7. Venous Anatomy
Venae comitantes accompany all perforating vessels to the flap in the
reverse flow flap. When a skin island is kept intact, venous egress
also occurs through the subdermal plexus.
8. Nerve Supply
Nerve Supply
Medial sural cutaneous nerve (S1-S2), which is a branch of the tibial
nerve within the popliteal fossa. This courses with the lesser
saphenous vein and cutaneous artery.
9. Nerve Supply
Dominant pedicle: Direct cutaneous artery and
lesser saphenous vein (D)
Minor pedicle: Myocutaneous perforating artery
(m) n, Sural nerve; v, lesser saphenous vein
11. Design and Markings
A, Design for anterograde flap. B, The design of
the distally based superficial sural artery flap on
the posterior aspect of the leg.
The skin island can be raised anywhere in the
lower two thirds of the leg. The pivot point of
the pedicle must be at least 5 cm above the
lateral malleolus to keep the anastomoses with
the peroneal artery.
13. GUIDE TO FLAP DISSECTION
For the anterograde flap, a Doppler probe is used to determine the
location of the course of the pedicle within the flap. Flap borders are
then incised through skin and deep fascia. Flap elevation begins
distally. The lesser saphenous vein and sural nerves are encountered
and divided, and both structures are included with the flap. As the
flap is elevated proximally toward the popliteal fossa, dissection is
performed in a subfascial plane between the deep fascia and the
underlying medial lateral gastrocnemius muscles. Careful dissection
proceeds as the popliteal fossa is approached and the entrance of
the medial superficial sural artery into the deep fascia is visualized.
Elevation proceeds until an acceptable arc of rotation is achieved to
cover the defect.
16. Reverse Sural Flap
The most common usage of the flap is for distal-third defects of the
leg. Here the reverse sural flap permits soft tissue reconstruction
without the need for microsurgery. It does not sacrifice any of the
three major arteries to the distal extremity. The distally based
reverse sural artery flap is based on the fasciocutaneous blood
supply of the distal posterior lateral leg. The structures supplying the
flap include the sural nerve superficially, the sural arteries, and the
lesser saphenous vein. These structures are all divided proximally
while the flap is elevated.
18. Adipofascial Flap
When skin is not required, but soft tissue fill is necessary, the sural
flap can be harvested, leaving skin in place, undermining in the
subcutaneous plane, carrying only the adipose tissue and fascia for
fill. Dissection is similar to that described previously
19. Delayed Flap
One of the weaknesses of the sural flap, especially the reverse variant, is
venous congestion, which may lead to partial flap loss. One solution is to
perform the flap in stages and create a delayed flap. When creating a delay
of the sural flap, the proximalmost portion of the flap is maintained with
the skin bridge. The remainder of the flap is dissected as previously
described, including complete elevation of the flap below the fascia. This
means that the skin island is being supplied by the vessels that normally
supply the flap, but a bridge of the skin has been maintained to allow
venous egress. The sural artery, sural nerve, and lesser saphenous vein
should be divided at the initial elevation, if possible. This allows axialization
of vessels within the flap over time, which allows it to become more reliant
on the retrograde vessels. At 7 to 10 days, this area of connection can be
divided in the office, and the flap can be rotated into position at 2 weeks.
21. Supercharged Flap
Another solution to the venous egress problem is to include the
lesser saphenous vein and some extension of it in the flap. Once the
flap is rotated into position, a venous anastomosis can be performed
between the lesser saphenous vein and any recipient vein in the
area. Another simple solution using this lesser saphenous vein is to
cannulate the vein and to drain this at the bedside at intervals. This
usually requires only 48 hours of such draining before flap
congestion is no longer an issue
Dasar arteri untuk flap sural adalah cabang yang berasal dari arteri poplitea atau dari arteri sural lateral. Dari asalnya, arteri biasanya mengikuti perjalanan nervus kutaneus sural lateral, mencapai fasia di atasnya kira-kira 5 cm di bawah lipatan poplitea. Arteri dan saraf berlanjut ke distal dalam jalur subfascial untuk jarak yang bervariasi. Baik pleksus suprafascial dan subfascial disuplai oleh pembuluh darah fasciokutaneus kelas B ini. Vena safena minor berjalan pada bidang subkutan antara kedua caput otot gastrocnemius. Vena comitantes berpasangan menyertai arteri fasciokutaneus; vena ini lebih disukai digunakan untuk membuat drainase vena untuk flap yang ditransplantasikan. Vena safena minor biasanya tidak digunakan.
Nervus kutaneus sural lateral muncul di fossa poplitea dari nervus peroneus komunis. Setelah membentuk nervus komunikans, biasanya menembus fasia profunda 5 sampai 10 cm distal dari lipatan poplitea yang mempersarafi fasia dan kulit dua pertiga lateral tungkai.
Perforator arteri sural pedikel yang dominan
Arteri Poplitea Sumber Regional.
Panjang 3cm.
Diameter 1,4mm.
Lokasi Pedikel ini turun dari fossa poplitea di antara caput musculus gastrocnemius dan lapisan fasia profunda dan berjalan ke inferior, superfisial dari musculus gastrocnemius.
Perforator Pedikel Minor dari arteri peroneal
Arteri Peroneal Sumber Regional.
Panjang 1cm.
Diameter 1mm.
Lokasi sepertiga distal kaki
Perforator neurokutaneus pedikel minor dari vasa nervorum saraf sural
Arteri Sural Sumber Regional.
Panjang 1cm.
Diameter Lebih besar dari 1 mm.
Lokasi Vasa nervorum anastomosis kaya dari saraf sural memberikan pembuluh perforasi neurokutan ke kulit dan fasia di atasnya.
Venae comitantes menyertai semua pembuluh darah perforasi ke flap di flap aliran balik. Ketika pulau kulit tetap utuh, jalan keluar vena juga terjadi melalui pleksus subdermal.
Pasokan saraf
Nervus kutaneus suralis medialis (S1-S2), yang merupakan cabang dari nervus tibialis di dalam fossa poplitea. Kursus ini dengan vena safena yang lebih rendah dan arteri kutaneous.
Pedikel dominan: Arteri kutaneus langsung dan vena safena minor (D)
Pedikel minor: arteri perforasi miokutaneus (m) n, saraf Sural; v, vena safena minor
A, Desain untuk flap anterograde. B, Desain flap arteri sural superfisial berbasis distal pada aspek posterior kaki.
Pulau kulit dapat dinaikkan di mana saja di dua pertiga bagian bawah kaki. Titik pivot pedikel harus setidaknya 5 cm di atas malleolus lateral untuk menjaga anastomosis dengan arteri peroneal.
Untuk flap anterograde, probe Doppler digunakan untuk menentukan lokasi pedikel di dalam flap. Batas flap kemudian diinsisi melalui kulit dan fasia dalam. Elevasi flap dimulai dari distal. Vena safena minor dan nervus suralis ditemukan dan dibagi, dan kedua struktur tersebut disertakan dengan flap. Saat flap diangkat ke proksimal menuju fossa poplitea, diseksi dilakukan pada bidang subfasia antara fasia profunda dan otot gastrocnemius lateral medial yang mendasarinya. Diseksi hati-hati berlanjut saat fossa poplitea didekati dan pintu masuk arteri sural superfisialis medial ke dalam fasia profunda divisualisasikan. Elevasi berlangsung sampai busur rotasi yang dapat diterima tercapai untuk menutupi cacat.
Penggunaan flap yang paling umum adalah untuk defek sepertiga distal kaki. Di sini flap sural terbalik memungkinkan rekonstruksi jaringan lunak tanpa perlu bedah mikro. Itu tidak mengorbankan salah satu dari tiga arteri utama ke ekstremitas distal. Flap arteri sural terbalik yang berbasis distal didasarkan pada suplai darah fasciokutaneus dari tungkai lateral posterior distal. Struktur yang mensuplai flap termasuk nervus sural secara superfisial, arteri sural, dan vena safena minor. Semua struktur ini terbagi secara proksimal saat flap diangkat.
Ketika kulit tidak diperlukan, tetapi pengisian jaringan lunak diperlukan, flap sural dapat diambil, meninggalkan kulit di tempatnya, merusak bidang subkutan, hanya membawa jaringan adiposa dan fasia untuk diisi. Diseksi mirip dengan yang dijelaskan sebelumnya
Salah satu kelemahan dari flap sural, terutama varian terbalik, adalah kongesti vena, yang dapat menyebabkan hilangnya sebagian flap. Salah satu solusinya adalah melakukan flap secara bertahap dan membuat flap tertunda. Saat membuat penundaan flap sural, bagian paling proksimal dari flap dipertahankan dengan jembatan kulit. Sisa flap dibedah seperti yang dijelaskan sebelumnya, termasuk peninggian total flap di bawah fasia. Ini berarti bahwa pulau kulit disuplai oleh pembuluh darah yang biasanya mensuplai flap, tetapi jembatan kulit telah dipertahankan untuk memungkinkan jalan keluar vena. Arteri sural, nervus sural, dan vena safena minor harus dipisahkan pada elevasi awal, jika memungkinkan. Hal ini memungkinkan aksialisasi pembuluh darah di dalam flap dari waktu ke waktu, yang memungkinkannya menjadi lebih bergantung pada pembuluh darah retrograde. Pada 7 hingga 10 hari, area sambungan ini dapat dibagi di kantor, dan penutup dapat diputar ke posisinya pada 2 minggu.
Solusi lain untuk masalah jalan keluar vena adalah memasukkan vena safena minor dan beberapa perluasannya ke dalam flap. Setelah flap diputar ke posisinya, anastomosis vena dapat dilakukan antara vena safena minor dan vena resipien di area tersebut. Solusi sederhana lainnya menggunakan vena safena yang lebih rendah ini adalah dengan mengkanulasi vena dan mengalirkannya di samping tempat tidur secara berkala. Ini biasanya hanya membutuhkan 48 jam pengeringan sebelum kemacetan flap tidak lagi menjadi masalah
