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
u003cpu003e22x10 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.u003cbr /u003eu003c/pu003e
Pre-operative considerations
u003cdivu003eThis case required a lot of planning.u003cbru003eu003c/divu003eu003cdivu003eThe only option to cover the defect would have been to use a free flap.u003cbru003eu003c/divu003eu003cdivu003eA “bridge”, or “conduit” flap was needed to bridge the flap to some donor vessels.u003cbru003eu003c/divu003eu003cdivu003eWe judged that the thoracodorsal vessels in the axilla were closer than the inferior epigastric vessels.u003cbru003eu003c/divu003eu003cdivu003eWe judged that a radial bridge flap would have been more reliable than using only vein graft.u003cbru003eu003c/divu003eu003cdivu003eThe patient needed to shift position twice during the surgery.u003cbru003eu003c/divu003eu003cdivu003eThe cephalic veins of both forearms, when studied with doppler and ultrasound, did not show to be patent; so we had to be prepared for a vein graft from the saphenous.u003cbru003eu003c/divu003eu003cpu003eu003cbru003eu003c/pu003e
Radial flap pre-op drawing
u003cpu003eFree radial bridge flap, pre op.u003cbru003eu003c/pu003e
ALT design pre-op
u003cpu003eu003cbr /u003eu003c/pu003e
Free radial bridge flap anastomosed to thoracodorsal vessels, with saphenous vein graft connected to thoracodorsal vein
u003cpu003eThe 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).u003cbru003eu003c/pu003e
Harvest of ALT flap and closure of donor site
u003cpu003eThe 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,u003cbr /u003eu003c/pu003e
Radial bridge flap congested
u003cpu003eNow 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.u003cbru003eu003c/pu003e
Flap to flap and vein graft anastomosis
u003cdivu003eThe patient is in lateral position with the right side up.u003cbru003eu003c/divu003eu003cdivu003eThe ALT with lateral vastus muscle is anastomosed, ALT artery to the distal aspect of the radial artery end to end, open book technique, end to end 9/0 ethilon, and the ALT vein to the saphenous vein graft, end to end with vein ring. The vein graft lies just underneath the skin of the radial flap.u003cbru003eu003c/divu003eu003cpu003eu003cbru003eu003c/pu003eu003cpu003eu003cbru003eu003c/pu003e
ALT wrapped to the side of the defect.
u003cpu003eThe patient is now turned into prone position, and the ALT is resting by the side of defect wrapped in a moist gauze. u003cbru003eThe congestion of the radial flap improved immediately after the ALT was connected. u003cbru003eNow the spinal surgeons performed extraction of infected hardware and performed a new fixation. u003cbru003eThe ALT was then inset into the defect.u003cbr /u003eu003c/pu003e
Defect
u003cpu003edefect before new spinal fixation, ALT wrapped in jauze nearby.u003cbr /u003eu003c/pu003e
Case completed
u003cpu003eAt 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.u003cbru003eu003c/pu003e
Post op day 1 – ALT flap
u003cpu003eThe 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).u003cbr /u003eu003c/pu003e
Post op day 1 – Radial bridge flap
u003cpu003ePost op day 1, the radial bridge looks good, with no signs of congestion.u003cbr /u003eu003c/pu003e
Post op 2 months and 2 weeks, free radial bridge
u003cdivu003ePost op radial bridge between axilla and ALT, well healed.u003cbru003eu003c/divu003eu003cdivu003eu003cdivu003e(In “photo after surgery”, the well healed ALT is shown, 2 months and 2 weeks after surgery)u003cbru003eu003c/divu003eu003c/divu003e
2 months and 2 weeks follow up
u003cpu003eView at follow up of ALT flap covering the large defect, with the radial bridge flap on the right side of the thoraxu003c/pu003e
Healed radial flap donor site
u003cpu003eu003cbru003eu003c/pu003e
Healed ALT donor site.
u003cpu003eu003cbru003eu003c/pu003e
Pearls
u003cpu003eu003cdivu003eAbsence of recipient vessels is not a limitation, if the surgeon can “bridge” between the defect and recipient vessels farther away. The radial bridge flap is a better option than just vein graft because:u003cbru003eu003c/divu003eu003cdivu003e1) There is an artery, much more reliable and not prone to kink or compressionu003cbru003eu003c/divu003eu003cdivu003e2) The cephalic vein behaves as a vascularized graft, and it protected from compression from the skin of radial flapu003cbru003eu003c/divu003eu003cdivu003e3) The radial skin allowes for coverage of the artery and vein, with less risk of compression and kinking.u003cbru003eu003c/divu003eu003c/pu003eu003cpu003ein this the case the cephalic vein was not usable, se we were forced to take a saphenous vein graft.u003cbru003eu003c/pu003eu003cpu003eWe believe that a radial flap plus a vein graft is still better than performing only vein grafts.u003cbru003eu003c/pu003e
Pitfalls
u003cpu003eWhen 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.u003cbru003eu003c/pu003eu003cpu003eIt is critical to plan accurately every step, inlcuding postion changes.u003cbru003eu003c/pu003eu003cpu003eWhen 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.u003cbru003eu003c/pu003eu003cpu003eu003cdivu003eOBS! Post op at 2 months and 2 weeks is shown in “photo after surgery”. u003cbru003eu003c/divu003eu003cdivu003eEverything healed uneventfully, there was no infection or wound rupture.u003cbru003eu003c/divu003eu003c/pu003eu003cpu003eu003cbru003eu003c/pu003e
Post-operative plan
u003cdivu003e1 week in side decubitus position, on air maddress, or prone.u003cbru003eu003c/divu003eu003cdivu003eafter the first week 30 minutes sitting, increase 30´every day.u003cbru003eu003c/divu003eu003cdivu003eFLAP Control after every position change!u003cbru003eu003c/divu003eu003cdivu003eNot allowed to lie on the vein graft (that is on the right side) for three months.u003cbru003eu003c/divu003eu003cpu003eu003cbru003eu003c/pu003e
u003cdivu003e1 week in side decubitus position, on air maddress, or prone.u003cbru003eu003c/divu003eu003cdivu003eafter the first week 30 minutes sitting, increase 30´every day.u003cbru003eu003c/divu003eu003cdivu003eFLAP Control after every position change!u003cbru003eu003c/divu003eu003cdivu003eNot allowed to lie on the vein graft (that is on the right side) for three months.u003cbru003eu003c/divu003eu003cpu003eu003cbru003eu003c/pu003e
u003cdivu003e1 week in side decubitus position, on air maddress, or prone.u003cbru003eu003c/divu003eu003cdivu003eafter the first week 30 minutes sitting, increase 30´every day.u003cbru003eu003c/divu003eu003cdivu003eFLAP Control after every position change!u003cbru003eu003c/divu003eu003cdivu003eNot allowed to lie on the vein graft (that is on the right side) for three months.u003cbru003eu003c/divu003eu003cpu003eu003cbru003eu003c/pu003e