Keywords
extremity replantation - LFCA - vascular grafting
Forearm replantation presents with many challenges including the requirement of significant
amounts of vascular graft for revascularization. The saphenous vein is frequently
harvested for use as a conduit in vascular reconstruction. However, many patients
have suboptimal saphenous veins due to peripheral vascular disease and atherosclerosis,
which places the vascular reconstruction and thus whole replant or flap survival,
at risk.
Less frequently, the lateral femoral circumflex arterial (LFCA) system is described
for use in vascular reconstruction. Prior use of LFCA grafts in the literature include
interposition grafts for head and neck free flaps,[1]
[2] lower extremity reconstruction,[3] added pedicle length to prefabricated flaps,[4] alternative to arteriovenous loops for flaps distant to recipient vessels,[4] ulnar artery reconstruction in hypothenar hammer syndrome,[5]
[6] and extremity flow-through revascularization.[4] We describe the use of the LFCA system for multiple arteriovenous grafts in the
case of a proximal forearm replantation.
Case
The patient was a 74-year-old right-hand dominant man who presented with a near-complete
proximal-third forearm amputation from entrapment in a log splitter. At the time of
the injury, the patient placed a tourniquet. The emergency medical services team briefly
let down the tourniquet on arrival to evaluate the injury; however, they immediately
reapplied it due to considerable blood loss. On arrival to the hospital, the patient
denied known medical problems and was emergently taken to the operating room for attempted
forearm replantation.
Intraoperatively, evaluation of the left upper extremity revealed a thin, tenuous
skin bridge, approximately 1.5 cm long, without intervening arterial, venous, or neural
supply ([Fig. 1]). The skin bridge was transected and a two-team approach to forearm replantation
was initiated. The extremity part underwent debridement of nonviable, crushed, or
contaminated muscle and skin on the back table. A longitudinal incision was made just
ulnar to the radial artery neurovascular bundle, which was proximally traced. The
radial artery and veins were dissected and thrombosis transected. The radial sensory
branch was identified and distally prepared. Similarly, the median nerve and the ulnar
artery, vein, and nerve were prepared with resection of thrombus or nonviable tissue
until healthy appearing tissue was encountered. The radius and ulna, which were fractured
transversely with some comminution, were shortened by approximately 4 cm.
Fig. 1 Preoperative forearm with a near-complete proximal-third forearm amputation from
entrapment in a log splitter and tourniquet in place. A skin bridge, approximately
1.5 cm long, was present without intervening arterial, venous, or neural supply.
With attention turned to the left forearm amputation stump, all nonviable muscle and
skin were debrided. The brachial artery in the proximal stump was divided into a radial
artery and an ulnar artery, which were both identified and dissected. The radial,
median, and ulnar nerves were identified, tagged, and trimmed back to healthy appearing
tissue. The ulnar artery, which was the largest artery on the amputated part, was
cannulated with a 6-French tube and connected to the ulnar artery of the stump. The
tourniquet was released to reestablish flow for a total ischemia time since injury
of 3.5 hours. Osteosynthesis was completed with a 3.5-mm locking compression plate
on both the radius and ulna. Although it appeared that nerve repairs would be coapted
without tension, the zone of injury of the vascular repairs would require a venous
graft.
Attention was turned to the lower extremity for vein graft where a longitudinal incision
was made in the medial lower leg, and Doppler ultrasound was used to confirm subcutaneous
veins; however, the patient had significant varicosities and peripheral vascular disease.
The saphenous vein appeared heavily sclerosed and unusable for vascular reconstruction.
Attention was instead turned to the thigh to examine the LFCA system for donor vessels.
A longitudinal line was made from the anterior superior iliac spine to the superolateral
patella, and the plane between the rectus femoris and vastus lateralis was dissected
until the descending branch of the LFCA system was identified. The LFCA system was
circumferentially dissected from distal to proximal of the venae comitantes, artery,
and transverse branch, which were harvested as vein and arterial grafts ([Fig. 2]).
Fig. 2 Lateral femoral circumflex arterial (LFCA) system as donor artery and veins. The
LFCA system was circumferentially dissected from distal to proximal of the venae comitantes,
artery, and transverse branch, which were harvested for interposition grafts in forearm
revascularization.
Vascular reconstruction first focused on the radial artery of the stump and part,
using a 4-cm reverse vein graft from the LFCA system with 9–0 nylon sutures. The radial
comitantes were anastomosed in similar fashion using 4-cm grafts from the venae comitantes
of the LFCA system with 9–0 nylon sutures. A venous repair with another 4-cm vein
graft was performed with the anterior interosseous neurovascular bundle, which had
a high volume of venous back bleeding. After pulsatile radial flow was confirmed with
Doppler, the ulnar artery shunt was clamped proximally and removed distally. Residual
clot that had surrounded the shunt was removed with no. 2 Fogarty catheter. A 4-cm
LFCA graft was utilized to repair the ulnar artery with 9–0 nylon sutures. The cephalic
vein was identified and anastomosed with a 4-cm vein graft and couplers and lastly,
another volar vein was identified and coupled with a 4-cm vein graft ([Fig. 3]). The radial sensory nerve, median nerve and ulnar nerve were repaired with tension-free
coaptations. The skin was loosely closed and a dressing was applied.
Fig. 3 Forearm replant after osteosynthesis, nerve repair, arterial and venous repair with
interposition grafts from the lateral femoral circumflex arterial system, and reestablishment
of blood flow with tourniquet release. Total ischemia time from injury was 3.5 hours.
The patient recovered well from the forearm replantation, maintaining good distal
forearm arterial inflow and venous outflow. The patient returned to the operating
room 3 days later for an Achilles allograft reconstruction of the volar forearm muscle
belly of the flexor digitorum profundus (FDP) to a side-to-side tenodesis of the proximal
FDP tendon stumps. The remaining open areas were closed with split-thickness skin
grafts. Subsequent surgeries included revision osteosynthesis of the radius and ulna,
and ulnar shaft revision osteosynthesis with iliac crest bone graft. He had wound-healing
difficulties with the saphenous vein harvest site but not with the LFCA donor site
([Fig. 4A, B]). At 15 months postoperatively, the patient had recovery of sensation in his volar
and dorsal digits, palm, and distal and proximal forearm ([Fig. 5]).
Fig. 4 Postoperative sites of the (A) saphenous and (B) lateral femoral circumflex arterial (LFCA). The saphenous donor site had wound breakdown
whereas the LFCA donor site healed without complication.
Fig. 5 Sensory recovery 15 months postoperative. Evaluator sizes listed on image of 2.83,
3.61, 4.31, 4.56, and 6.45 correspond to target forces of 0.07, 0.4, 2.0, 4.0, and
180 g, respectively. Colors correspond to threshold of sensation: blue, diminished
light touch; purple, diminished protective sensation; red, loss of protective sensation;
red lined, tested with no response.
Discussion
Forearm replantation involves the complex reconstruction of many structures in the
upper extremity. Vascular reconstruction often involves autograft conduits to ensure
that the anastomosis lacks tension. The saphenous vein is the standard conduit harvested
but can be compromised due to peripheral vascular disease, as seen with our case patient,
which may compromise revascularization. Conversely, the descending branch of the LFCA
system is often spared from peripheral vascular disease. In a retrospective review
examining angiograms of patients with suspected peripheral vascular disease, Halvorson
et al found that the descending branch of the LFCA system was spared from atherosclerosis
in 87% of patients.[7]
The LFCA system is located along a longitudinal line connecting the anterior superior
iliac spine to the superolateral patella. The descending branch of the LFCA system
can be found within the plane between the rectus femoris and vastus lateralis. In
a cadaveric study by Zenn et al, the descending branch of the LFCA system typically
has a mean pedicle length of 20.5 cm, proximal arterial diameter of 3.4 mm, distal
arterial diameter of 1.9 mm, and proximal venous diameter of 3.9 mm. Of the eight
fresh legs of the five cadavers studied, 60% percent of had two sizable venae comitantes,[4] providing vessel of ample size and length for reconstruction.
Furthermore, the LFCA system provides both arterial graft in addition to the venae
comitantes grafts, which give the LFCA system a significant advantage over venous
grafts in arterial reconstruction. Arterial conduit grafts have significantly increased
patency rates compared with venous conduits in distal upper extremity bypass surgery.[8] Masden et al examined 152 grafts in upper extremity revascularization (19 of 152
were arterial conduits) in a systematic literature review, finding rates of 100% arterial
conduit patency and 85% vein graft patency, with a statistically significant difference
in patency rates.[8]
The LFCA system provided an advantageous alternative to the saphenous vein graft,
contributing significant amounts of vascular conduit, including arterial graft that
may improve chances of replantation patency. The limitation of the LFCA system as
a donor site is its inability to use the the fasciocutaneous anterolateral thigh (ALT)
flap of the ipsilateral leg; however, the contralateral leg can provide an ALT flap
for reconstruction if needed.
Conclusion
The LFCA system is a viable and possible superior alternative to the saphenous vein
in vascular graft reconstruction, providing significant amounts of venous and arterial
graft with potentially decreased donor site morbidity.
