Keywords
soft tissue reconstruction of extremities - longest free flap - boomerang-shaped extended
rectus abdominis myocutaneous flap
Introduction
Limb salvage has always been the goal of all reconstructive surgeons and complex limb
defects challenge surgeons to come up with innovative modifications.
Boomerang-shaped extended rectus abdominis (BERAM) and latissimus dorsi (LD) flaps
individually are well documented for reconstructive procedures.[1]
[2] Vein grafts have been used to extend the reach of microvascular flaps.[3]
Extensive leg defects that require flap cover longer than that provided by commonly
done free flaps like the anterolateral thigh (ALT) and LD flap even in chimeric forms
is a challenging problem. When vascularity of foot and sole sensation is intact, limb
salvage attempt is warranted.[4]
A combination of all, which has not been described before, were used to perform a
microvascular free tissue transfer to salvage the lower limb of a young boy post a
devastating degloving injury.
Case Report
A 16-year-old boy with an alleged history of road traffic accident presented to us
3 days after the injury with a request to salvage the limb as he was counseled for
above-knee amputation where he was resuscitated and stabilized with an external fixator.
We were presented with multiple challenges; delayed presentation with a circumferential
degloving injury of the right lower limb of 53 * 24 cm extending from the upper thigh
to the lower third of the leg with exposed knee joint, with only the medial gastrocnemius
and part of soleus intact, full length of fractured tibia exposed and absent fibula
and a single vessel limb with only the posterior tibial (PT) vessels and nerve present
([Supplementary Fig. 1], available in the online version).
Intact vascularity and sole sensations along with age prompted us toward limb salvage
after thorough counseling. Options were a double free flap, which on planning in reverse
was still falling short because of the circumferential exposure of the knee joint
and the length of the defect. An extended BERAM flap with LD myocutaneous flap as
one continuous tissue unit emerged as an option, which on planning gave us the maximum
possible tissue coverage. Still, the reach of the pedicle was short so we planned
to extend it by the use of vein grafts. Marking was done in reverse with maximum width
permissible for primary closure.
The sequence of events as to how a 7-hour surgery changed the patient's life were:
-
Wound debrided ([Fig. 1])
-
Two-team approach was opted for, one for flap elevation and one for recipient site
preparation with vein graft and vessels exposure ([Fig. 2])
-
Great saphenous interposition vein graft harvested from the left lower limb
-
Femoral vessels exposed in Hunter's canal and PT vessels in lower one-third of the
leg
-
BERAM portion of flap harvested and pedicle isolated with lateral continuation of
the BERAM skin paddle onto the LD territory
-
Position changed for LD flap harvest in continuity ([Fig. 3])
-
Flap perfusion confirmed using indocyanine green (ICG) perfusion scan ([Supplementary Fig. 2], available in the online version) ([Video 1])
-
Vein graft tagged and reversed for extension from the femoral vessels in an end-to-side
fashion
-
LD portion disconnected and the flap waltzed down to the thigh pivoting on the deep
inferior epigastric vessels, thoracodorsal vessels anastomosed to the vein grafts
harvested from opposite limb in an end-to-end fashion ([Fig. 4A, B])
-
BERAM pedicle divided and waltzed down to the leg, anastomosed to PT vessels in an
end-to-side fashion
-
Antibiotic beads put in the cavity on the bone and joint
-
Flap inset done over drains ([Fig. 5])
-
Donor site closed primarily ([Fig. 6])
-
Meshed split-thickness skin graft harvested for raw areas on postoperative day 5 ([Fig. 7])
-
Patient discharged on day 21
-
Started weight bearing on day 90 ([Fig. 8])
Fig. 1 Right leg defect post-debridement.
Fig. 2 Plan: Boomerang-shaped extended rectus abdominis myocutaneous flap with latissimus
dorsi myocutaneous flap.
Fig. 3 Flap post-elevation.
Fig. 4 (A) Schematic diagram showing plan of waltzing and anastomosis of thoracodorsal and
deep inferior epigastric pedicle. (B) Detaching one end of the flap, that is, latissimus dorsi (LD) flap from the source
and waltzing, pivoting on the deep inferior epigastric pedicle down to cover the knee
joint with simultaneous donor site closure, anastomosis of thoracodorsal pedicle to
femoral vessels in end-to-side fashion using interposition great saphenous vein graft
harvested from the left side and just before division of the DIEA pedicle showing
the length of the fully extended flap.
Fig. 5 Flap post-inset on table. Latissimus dorsi (LD) muscle covered the knee joint circumferentially
and boomerang-shaped extended rectus abdominis myocutaneous (BERAM) portion covered
the exposed tibia.
Fig. 6 Donor site closure with Prolene mesh, anterior rectus sheath closure, and primary
skin closure.
Fig. 7 Early and late follow-up post-split-thickness skin graft (SSG).
Fig. 8 Patient functional outcome at 8 months' follow-up.
The postop outcome was uneventful barring some graft loss, which was managed by dressings.
Our lifeboat was to cover the knee joint with a free LD and a cross leg flap for covering
the tibia.
Patient has foot drop at present, will be addressed once bone growth is complete.
Discussion
A free rectus myocutaneous flap has a long pedicle with a large vascular lumen with
a well-described vascular architecture of the DIEA and the paraumbilical perforators.[5]
[6]
[7]
[8] Because of its boomerang-like shape, Koul et al named free rectus abdominis flap
design the free BERAM flap.[1]
According to Taylor et al, the paraumbilical cutaneous perforator(s) can be included
in the flap to create a diagonally positioned upper skin island that extends beyond
the rectus muscle from the umbilicus to the costal margin. These perforators connect
to the anterior branches of the lateral intercostal vessels at a 45-degree angle to
the anterior axillary line via choke vessels. This idea served as the foundation for
both our flap and the original BERAM flap.[8]
In adults, BERAM flaps consistently yield flap lengths that are 42.2% longer than
regular ALT flaps and 32.6% longer than standard LD flaps. In children, the disparity
is more noticeable.[1] If the BERAM flap is raised to the mid-axillary line and the LD flap is raised with
skin paddle fully centered on the muscle, the vascularity of the flap is trustworthy.
Waltzing of the flap ensures practically no cold ischemia time.
Additionally, vein grafts extended reach of the flap to the working area of the defect.
The ICG perfusion analysis demonstrated good flap perfusion, particularly in the intervening
tricky zone between the LD and BERAM region.[1] A high success rate, preservation of existing vessels in an injured extremity, increased
operational planning flexibility, and technical simplicity for vessel access are the
benefits of end-to-side anastomoses.[9] Compared to any double free flap, this flap, in our experience, offers the most
tissue coverage, especially in longer than larger defects. It also saves the only
available thigh for skin graft harvesting, which would otherwise be used for ALT elevation
that in turn would need a skin graft for donor site coverage.
Conclusion
Extended BERAM with myocutaneous LD provides the longest tissue for coverage with
a dependable pedicle for limb salvage procedures, making it a great and safe choice
for extensive defects that are longer than wide enough to justify primary closure
of the donor site.
Video 1
