Microvascular Anastomotic Coupler: An Unexpected Adverse Event
09 January 2019 (online)
We read with great interest the article by Stranix et al on the comparison of hand-sewn versus coupled venous anastomoses in traumatic lower extremity reconstruction. We thank the authors for their thorough collection of data on the subject and sharp analysis. Coupling device for end-to-end venous anastomoses has proven its value  its high cost is balanced with the shorter operative time. Although we agree coupler device can be of a great help to perform venous anastomosis even in a traumatic lower limb, we would like to draw attention to a peculiar issue we encountered using this device.
We report a case of a 60-year-old-patient with a severe electrical burn on the left foot ([Fig. 1A]). We performed a free anterolateral thigh (ALT) flap to cover the hallux metatarsophalangeal joint and first phalanx exposure. Two venous anastomoses were performed with coupler devices (GEM Coupler, Synovus, Birmingham, United Kingdom) between the ALT pedicle veins and the dorsalis pedis veins. The flap healed without acute complication and a satisfactory flap integration. After 9 months postoperatively, the patient was very satisfied with the overall result but complained of a small discomfort on the dorsum of the operated foot ([Fig. 1B]). He had the odd sensation to have a stone inside his shoe. After a close examination, we realized he was feeling the coupling devices underneath the skin. An X-ray confirmed the diagnosis ([Fig. 1C]). A revision surgery was performed to remove all venous couplers. We first clamped the veins for 10 minutes, to confirm that the flap vascularization was not altered, then completely ligatured them. The artery was left anastomosed. No complication happened after this last procedure.
Anterolateral thigh flap is a fasciocutaneous flap. Its blood supply is initially provided by its freshly anastomosed pedicle. Then, when edges are healed, dermal, subdermal, and perifascial networks may sustain the entire flap vascularization. Ligation of the pedicle can be safely done 3 weeks after the surgery. Another venous anastomosis could have been realized to replace the coupler if the flap did not include any skin paddle (pure muscle flap).
A few long-term complications associated with the use of microvascular anastomotic devices have been described. However, Zomerlei and Komorowska-Timek reported a migration of the venous coupler at 6 months postoperatively; furthermore, anastomotic couplers are implanted devices and are also subject to infection, perforation, erosion, and dislodgement.
Consequently, to avoid this issue, we would recommend either to perform a hand-sewn venous anastomosis when the pedicle is underneath a thin skin, which is frequent in limbs' extremities, or at least inform preoperatively the patient about this possible complication.
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