Keywords: Double free flap, flap to flap, free radial bridge flap, radial conduit, vein graft, lower back defect.
Authors: Andrea Donfrancesco, MD and Jenny Löfgren, MD, Karolinska University Hospital, Stockholm, Sweden
Abstract
A challenging case of midline mid-lower back defect is presented. The patient underwent previously vertebral chondrosarcoma resection, spine fixation and post-operative radiotherapy, and was re-operated 2 years after because of vertebral bone re-absorption and rupture of the previously done spinal fixation. The skin and soft tissue never healed and the patient had a 22 x 10 cm defect of the mid-lower back with exposed fixation material, exposed dura above the spinal cord, and radiotherapy damaged tissue around. No local reconstructive option was feasible. We reconstructed the defect with a free ALT, connected to a free radial bridge flap and a saphenous vein graft, hooked up to the thoracodorsal vessel, and a new spinal fixation was performed. Reconstruction was successful.
Patient medical history
The patient is previously healthy, has no past medical history. She developed a bulge on the back at T12 level. MRI and biopsy showed chondrosarkoma. She was operated at Karolinska University Hospital in May 2022 with sarkoma resection, spinal fixation T 10 to L3, primary skin closure, and post- operative radiotherapy.
After 2 years the patient presented with osteoporotic reabsorption of bone, fusion/collapse of L1-L2, and rupture of a shaft of the previous fixation. The patient underwent again surgery by the spine surgeon at our hospital in July 2024 with extraction of the previously done fixation, and a new longer fixation was performed T5 to L5. Beacuse the soft tissues ware previously irradiated, a left pedicled muscle latissimus flap was performed to have better coverage of the upper potion of the defect. The wound ruptured and got infected, with expsure of the spinal fixation material; the patient received targeted IV antibiotics and the wound which was 22×10 cm was covered temporarily with a VAC.
In October 2024 at our hospital, we decided to achieve coverage of the wound and re-do the spinal fixation. There were no valid recipient vessels for a free flap near the defect, and no local flaps were possible because the tissue around the wound was very damaged by radiotherapy.
Description of the surgery: We raised av left sided free radial flap (21+7 cm), at the same time as a big right sided ALT (34×15 cm) including vastus lateralis was raised, and the right thoracodorsal vessels in the axilla were exposed. All the superifical veins of the forearm were thrombosed including the cephalic vein. Thus, a 20 cm graft of saphenous vein was harvested from the right thigh.
The Radial flap was hooked up to the axilla, radial artery to thoracodorsal artery, larger Vena Comitans to the serratus branch vein. The saphenous vein graft was anastomosed to the thoracodorsal vein with a vein ring.
The ALT flap was detached from the thigh, flushed with heparin, and kept in iced water. The patient was turned from supine position to side position, with the right side up. In the meantime the radial flap got congested. The ALT was anastomosed to the distal side of the radial artery, and the ALT vein to the saphenous vein graft. The congestion of the radial flap improved (presumably because of flow through) and the ALT was very well blood supplied. Two doppler cooke probes were placed distal to each arterial anastomosis.
The ALT was wrapped in a moist gauze and stabilized to the skin nearby the defect. avoiding tension to the pedicle. The patient was now turned into prone position, and the spine surgeons extracted the infected/exposed fixation material and performed again spinal fixation. The ALT was inset now in the defect.
The patient was immobilized on an air madress in side position for 1 week. Both flaps healed with no complications. The ALT donor site was reoperated several weeks after because of split transplant graft loss. The patient now can walk.
Before and After
Patient examination
22×10 cm defect of the mid lower back, with exposed dura above the spinal cord, exposed hardware material. The skin surrounding the defect is hard, inelastic and radiodamaged. No local flaps are possible. No recipient vessels are present nearby the defect for a free flap.
Pre-operative considerations
Radial flap pre-op drawing
Free radial bridge flap, pre op.
ALT design pre-op
Free radial bridge flap anastomosed to thoracodorsal vessels, with saphenous vein graft connected to thoracodorsal vein
The left free radial flap was raised, the proximal part of the artery anastomosed to the thoracodorsal artery of the right axilla, and the larger Vena Comitans to the vein of the serratus branch. When raising the radial flap, all superficial veins including the cephalic were thrombosed, thus a saphenous vein graft 20 cm was harvested and anastomosed to the thoracodorsal vein. (Unfortunately pictures of the graft were not taken).
Harvest of ALT flap and closure of donor site
The ALT/vastus lateralis muscle was harvested, flushed with heparin and placed in iced water. Closure of the ALT donor site was performed partially with primary closure and with split thickness skin graft,
Radial bridge flap congested
Now the patient is turned from supine into lateral position with the right side up. The radial flap showed signs of congestion. At this time we thought to just continue the surgery and to hook up the ALT to the radial flap artery and to the vein graft. If the radial flap should have continued to be congested, this would not have impacted the ALT, and we would have just treated the radial flap with leeches.
Flap to flap and vein graft anastomosis
ALT wrapped to the side of the defect.
The patient is now turned into prone position, and the ALT is resting by the side of defect wrapped in a moist gauze.
The congestion of the radial flap improved immediately after the ALT was connected.
Now the spinal surgeons performed extraction of infected hardware and performed a new fixation.
The ALT was then inset into the defect.
Defect
defect before new spinal fixation, ALT wrapped in jauze nearby.
Case completed
At the end of the surgery, the ALT and vastus muscle cover completly the defect. Dressings are placed. One can see the radial bridging the axilla to the ALT, with no congestion, and no compression of the underlying vein graft.
Post op day 1 – ALT flap
The day after surgery, the ALT looks good, with no signs of congestions, and both cooke doppler probes give good arterial signal. (one should note that the whole ALT is drained solely by the vein graft).
Post op day 1 – Radial bridge flap
Post op day 1, the radial bridge looks good, with no signs of congestion.
Post op 2 months and 2 weeks, free radial bridge
2 months and 2 weeks follow up
View at follow up of ALT flap covering the large defect, with the radial bridge flap on the right side of the thorax
Healed radial flap donor site
Healed ALT donor site.
Pearls
in this the case the cephalic vein was not usable, se we were forced to take a saphenous vein graft.
We believe that a radial flap plus a vein graft is still better than performing only vein grafts.
Pitfalls
When planning a radial bridge flap, ultrasound of the cephalic vein should be performed to ensure it is patent. Some patients received many medications through peripheral IV lines in superficial veins of the forearm, and the cephalic vein might not be patent. In this case one must plan for a vein graft.
It is critical to plan accurately every step, inlcuding postion changes.
When performing a long vein graft, if it does not lie flat, and there is a risk of tension, compression or kink, it is critical to have a good post operative mobilization plan for the patient. in this case the pat had to wait 1 week to be allowed to sit, as the risk was too high that the weigh of flaps could have pulled on the graft.
Post-operative plan
References
- The radial forearm free flap as a “vascular bridge” for secondary microsurgical head and neck reconstruction in a vessel-depleted neck Pedro Ciudad 1 2, Mouchammed Agko 1, Shivprasad Date 1, Wei-Ling Chang 1, Oscar J Manrique 1, Tony C T Huang 1, Federico Lo Torto 1, Emilio Trignano 1, Hung-Chi Chen 1