Answer:
a) bilateral gluteus advancement flap:
The gluteus maximus has its origins on the gluteal line of ilium and
sacrum and inserts in the greater tuberosity of the femur and the iliotibial
band of the fascia lata. The two dominant pedicles are the superior gluteal
artery and the inferior gluteal artery . For the bilateral gluteus advancement
flap the superior half of each gluteus muscle, with overlying skin island
is released from its origin and insertion. The superior gluteal artery
is identified and preserved. Each myocutaneous unit is advanced to the
midline. Donor site closure is performed with V-Y advancement. The inferior
half of each gluteus maximus is preserved avoiding hip stability. This
technique is useful in the management of sacral defects in the ambulatory
patient.
b) gluteal rotation and sliding flap:
For the gluteal sliding flap, dissection of the flap is from medial
to lateral with the origin of the gluteus maximus completely detached.
Care is taken to avoid injury to the underlying gluteal vessels. The innervation
is maintained and the intact muscle is mobilized medially. The medial edge
is closed in the midline to its opposite member. This way gluteus maximus
integrity and function are maintained.
In a gluteal rotation flap the insertion is divided and the gluteal muscle is rotated medially to cover defects of the sacrum or a paddle of skin can be taken from the posterior thigh to cover trochanteric ulcers.
c) v-y semitendinous flap:
The semitendinous is one of the three hamstring muscles. Its
origin is the isheal tuberosity and attaches medially to the tibia. The
dominant blood supply is the first perforator from the profunda on the
deep lateral surface. The overlying skin on posterior thigh can be advanced
with the muscle in a V-Y advancement to cover ischeal ulcers.
d) TFL flap:
The tensor fascia lata muscle arises from the anterior part of the
outer lip of the iliac crest and the lateral surface of the anterior superior
iliac spine. It inserts into the fascia lata at the junction of the upper
and mid thigh. The lateral circumflex femoral artery from the profunda
enter the muscle approximately 6 cm below the anterior superior iliac spine.
Dissection of the TFL is from distal to proximal below the plane of the
fascia lata. The TFL flap can be transposed to cover trochanteric,
ischial, and sacral areas.
e) posterior thigh flap:
The posterior thigh flap or gluteal thigh flap is base on the inferior
gluteal artery and its perforator to the cutaneous posterior thigh. The
point of rotation is 5 cm above the ischial tuberosity. The central axis
of the flap is midway between the greater trochanter and the ischial tuberosity.
The flap is designed to be less than 12 cm in width and extended to within
8 cm of the popliteal fossa. Dissection is carried distal to proximal below
the plane of the fascia lata. The defect is closed primarily. The flap
can be rotated to reach the sacrum and trochanter.
f) total thigh flap:
A posterior longitudinal incision is made along the lateral border
of the long head of the biceps, in the lower one-third of the thigh. The
incision is then continued proximally over the lateral intermuscular septum
up to the inferior border of the gluteus maximus muscle. An estimate of
the flap length is made and usually a circumferential incision is made
at the distal end of the femur in the popliteal region. An incision is
made through the deep fascia to enter the lateral intermuscular septum.
This relatively avascular plane lies between the biceps femoris muscles
and the vastus lateralis, and offers a direct approach to the femur. An
incision is made through the periosteum over the posterior aspect of the
femur. Using subperiosteal dissection, the vastus lateralis is reflected
laterally and the adductor magnus muscle is reflected medially up to the
level of amputation. The distal end of the flap is then folded cephalad.
g) vastus lateralis flap:
The vastus lateralis arises from the greater trochanter along the posterolateral
aspect of the femur to insert into the superolateral border of the patella.
The blood supply comes from the lateral femoral circumflex artery through
a descending branch. The muscle is exposed through a lateral thigh incision
from a point 10 cm below the superior iliac spine at the level of the greater
trochanter to the lateral condyle of the femur. Using blunt dissection
the plane between the vastus lateralis and rectus femoris is mobilized.
The vastus lateralis is separated from the vastus intermedius sharply,
working from the greater trochanter downward. The insertion is divided
and the flap elevated proximally from the femur. It can be used for trochanteric
and ischial ulcers. The defect is closed primarily.