Microsurgery Principles

During an end-to-end arterial anastomosis for a free flap, the vessel appears patent after clamp release, but inflow is poor and the distal artery remains collapsed. Inspection shows that one posterior-wall suture has inadvertently captured the opposite vessel wall. What is the most appropriate management?

A 61-year-old man requires a free flap for a distal leg defect. The posterior tibial artery is the only dominant vessel supplying the foot, but it has a suitable side branch and good flow. What is the most appropriate arterial anastomotic strategy?

During harvest of a free flap, an interposition vein graft is required to reach the recipient artery. The graft is taken from a vein containing valves. What is the most important technical principle?

A free flap has been harvested, but recipient-vessel preparation is delayed for 90 minutes. Which measure best limits ischemic injury while the flap remains detached?

During venous anastomosis with a microvascular coupler, the vein walls are thin and the two vessel diameters differ slightly. What is the most important requirement before the device is closed?

A 48-year-old woman undergoes a buried free flap for pharyngeal reconstruction. Postoperatively, the implantable Doppler signal becomes weak and intermittent, but the external skin-monitoring segment remains warm with normal capillary refill. What is the most appropriate next step?

A patient undergoing free-flap reconstruction has a hemoglobin level of 72 g/L but is hemodynamically stable, normoxic, and has a well-perfused flap. What is the most appropriate transfusion principle?

During exploration of a thrombosed free flap, the surgeon removes clot from the artery and restores temporary flow. A residual narrowing is visible at the anastomosis, and the vessel wall appears bruised. What is the most appropriate next step?

A free flap for hand reconstruction has excellent arterial inflow but no suitable recipient vein remains after multiple traumatic injuries. A superficial vein can be reached only with a long conduit. What is the most appropriate reconstructive principle?

A replanted fingertip has adequate arterial inflow after microsurgical repair, but no vein suitable for anastomosis can be identified. The fingertip becomes congested while remaining warm and bleeding bright red after pinprick. What is the most appropriate salvage strategy?

A 63-year-old man requires a free anterolateral thigh flap for coverage of an open distal tibial fracture. Angiography shows that the posterior tibial artery is the only reliable artery supplying the foot. It has good flow and an appropriate segment for microsurgical access. What is the most appropriate arterial anastomotic strategy?

During a venous microvascular anastomosis using a coupling device, the recipient vein measures 3 mm and the flap vein measures 2.5 mm. Both veins are healthy and reach without tension. What is the most important technical requirement before closing the coupler?

A buried free jejunal flap is used for pharyngeal reconstruction. Six hours after surgery, the implantable venous Doppler signal disappears, but the patient remains hemodynamically stable and the external monitoring segment appears unchanged. Repositioning the neck and checking the monitor connections do not restore the signal. What is the most appropriate next management step?

Two hours after free gracilis transfer for lower-extremity reconstruction, the flap becomes congested and the Doppler signals weaken. Examination reveals a rapidly enlarging tense hematoma beneath the flap. What is the most appropriate management?

A large free muscle flap experiences prolonged warm ischemia because recipient-vessel preparation is unexpectedly difficult. After technically patent arterial and venous anastomoses are established, the pedicle has strong flow but the muscle remains mottled with poor capillary perfusion. What is the most likely explanation?

A patient with a technically satisfactory free flap has no personal or family history of thrombosis and no known hypercoagulable disorder. The surgical team considers routine therapeutic heparin infusion solely to prevent microvascular thrombosis. What is the most appropriate principle?

During free-flap transfer, the selected recipient vein has poor filling, collapses after clamp release, and provides minimal back-bleeding. A second recipient vein nearby has a larger caliber and reliable flow. What is the most appropriate operative decision?

A patient has a traumatic segmental defect of the radial artery together with a large dorsal hand soft-tissue defect. The hand remains viable through collateral circulation, but restoration of radial arterial continuity is desirable. Which reconstructive strategy is most appropriate?

While preparing a 1.5-mm artery for anastomosis, the surgeon sees loose adventitia extending beyond the cut edge and tending to fold into the lumen. What is the most appropriate vessel preparation?

During radial forearm free-flap transfer, the deep vena comitans is anastomosed and confirmed patent, but the flap remains mildly congested. The cephalic vein becomes markedly distended after arterial reperfusion. What is the most appropriate next step?

A 34-year-old man undergoes thumb replantation after a sharp amputation. The digital artery has been repaired, but the proximal and distal nerve ends are separated by a 12-mm gap when the thumb is positioned normally. Direct approximation would require marked tension. What is the most appropriate nerve reconstruction?

During digital nerve repair, the surgeon has achieved accurate alignment of the nerve ends without tension. What is the most appropriate microsurgical suturing principle?

A 29-year-old man undergoes replantation of an amputated forearm segment after prolonged transport. The amputated part contains a large muscle mass and has been kept at room temperature for several hours. Which factor most strongly increases the risk of systemic reperfusion complications?

During free-flap harvest, the vascular pedicle is accidentally divided shorter than planned. The flap reaches the recipient vessels only with excessive tension. Both recipient artery and vein are otherwise healthy. What is the most appropriate solution?

A 60-year-old woman undergoes free-flap breast reconstruction. Postoperative monitoring shows a gradual fall in tissue oxygenation, but the flap remains warm with an audible arterial signal and increasingly rapid capillary refill. What is the most likely vascular problem?

A free flap is perfused through a small artery that develops repeated thrombosis despite revision. Laboratory testing reveals previously unrecognized severe thrombocytosis, and no residual technical defect is found. What is the most appropriate management principle?

During microsurgical anastomosis, the surgeon irrigates the lumen before completing the final sutures. What is the main purpose of gentle intraluminal irrigation with an appropriate solution?

A 48-year-old man undergoes free-flap reconstruction of a foot defect. The flap is viable, but the external Doppler signal is difficult to distinguish from a nearby native artery. What is the most appropriate monitoring strategy?

During exploration of a congested free flap, the venous anastomosis is patent, but the vein is compressed where it passes beneath a tight fascial tunnel. What is the most appropriate management?

A 53-year-old woman undergoes free-flap breast reconstruction. Twelve hours later, the flap develops progressive swelling and venous congestion. Exploration reveals a patent primary venous anastomosis but inadequate total outflow from the flap. A second suitable flap vein and recipient vein are available. What is the most appropriate next step?

A 36-year-old man undergoes free-flap reconstruction after a crush injury to the forearm. During recipient-artery preparation, the vessel has pulsatile flow, but the cut edge shows circumferential bruising and separation of the intima from the media. What is the most appropriate next step?

During inset of a free anterolateral thigh flap into a lower-leg defect, the flap must be rotated 180 degrees. After inset, arterial inflow remains present, but the flap becomes progressively congested and the venous Doppler signal weakens. The venous anastomosis appears patent. What is the most appropriate next step?

Four hours after free-flap reconstruction, the flap becomes pale and loses its Doppler signal. At exploration, an arterial thrombus is removed and flow returns, but a focal stenosis and damaged intima remain at the original anastomosis. What is the most appropriate definitive management?

A 59-year-old woman undergoes free rectus abdominis muscle transfer. Because recipient-vessel preparation is delayed, the detached flap remains at room temperature for an extended period. Which intervention best reduces ongoing ischemic injury while the flap is awaiting revascularization?

A patient requires a free flap for a distal lower-leg defect, but no suitable recipient vessels are available near the wound. Healthy femoral vessels are present proximally, and the surgeon plans an arteriovenous loop using a vein graft. What is the most important reconstructive principle?

During free fibula flap reconstruction of the mandible, the skin paddle appears well perfused after reperfusion. The surgeon is concerned about monitoring the buried bone segment postoperatively. What is the most appropriate principle?

A 27-year-old man undergoes replantation of a completely amputated thumb. Arterial repair produces good inflow, but only one small dorsal vein is initially identified. What is the most appropriate venous strategy?

A buried free flap used for skull-base reconstruction has an implantable arterial Doppler signal but no venous signal four hours after surgery. The patient is stable, and there is no external skin paddle. Rechecking the device connections does not restore the venous signal. What is the most appropriate management?

During free-flap surgery, both arterial and venous flow remain sluggish despite technically satisfactory anastomoses. The patient is hypothermic, acidotic, and hypotensive after prolonged anesthesia. What is the most appropriate next management step?

A 66-year-old man with peripheral arterial disease requires a free flap for heel reconstruction. The proposed recipient artery is calcified and rigid, but duplex examination identifies a healthier segment more proximally with good flow. What is the most appropriate operative plan?

A 28-year-old man presents with a complete proximal forearm amputation after an industrial accident. The amputated part has been cooled appropriately, but warm ischemia before cooling was prolonged. After rapid debridement and bone shortening, tendon and nerve reconstruction would require several additional hours before definitive vascular repair. What is the most appropriate microsurgical priority?

During free-flap reconstruction of an irradiated neck, the recipient vein is thick-walled, fibrotic, and poorly compliant. A venous coupler cannot evert the vessel edge evenly without tearing it. What is the most appropriate next step?

During anterolateral thigh free-flap transfer, the recipient artery initially has good pulsatile flow. After repeated traumatic handling, the vessel develops poor inflow and a visible intimal flap extending proximally beyond the cut edge. What is the most appropriate management?

A 32-year-old woman undergoes free functional gracilis transfer for facial reanimation. The vascular anastomoses are satisfactory, but the selected donor motor nerve reaches the obturator nerve branch only when both nerves are placed under marked traction. What is the most appropriate nerve-repair strategy?

A 46-year-old woman with secondary upper-limb lymphedema undergoes lymphaticovenular bypass. Intraoperative mapping identifies one functioning lymphatic channel with visible forward flow and a nearby small venule with minimal reflux. What is the most appropriate microsurgical principle?

A free muscle flap develops severe mottling after prolonged ischemia. At exploration, both anastomoses are patent and no pedicle kink is present, but multiple small thrombi are suspected within the distal flap microcirculation. Standard thrombectomy cannot reach these vessels. What is the most appropriate salvage principle?

During a perforator free-flap operation, indocyanine-green angiography shows excellent perfusion of most of the flap but persistent absence of fluorescence in a distal skin segment. Pedicle flow and the selected perforator are satisfactory, and releasing inset tension does not improve the distal area. What is the most appropriate management?

On postoperative day 4 after free-flap reconstruction of a traumatic leg defect, the flap suddenly becomes congested and the venous Doppler signal disappears. The patient also has increasing wound drainage and surrounding erythema. What is the most appropriate next management step?