April 2020 HSC Section 4 - Plastic and Reconstructive Problems

Volume 144, Number 1 • Nose Microvascular Reconstruction

established and well supported during each stage to overcome skin shrinkage, scar contracture, and airway narrowing. The higher the nostril arches and available nostril lining, the less the risk of nos- tril stenosis. Temporary or permanent stents are not used. Less often, when past donor forearm injury, damaged contralateral neck vessel, or thickness of the forearm fat precludes the two-fold design, the flap is folded in a single plane and anastomosed to the ipsilateral neck vessels. For an ipsilateral anas- tomosis, the flap is positioned to place the radial portion of the skin paddle and adherent pedicle under the dorsal graft, lining the vault and floor surface. The ulnar skin is folded to cover the dor- sal graft. Lining for a columella is not initially restored. When the injury is internal only, circumferen- tial lining defects of the vault and floor are resur- faced with a single rectangular flap. An intraoral buccal sulcus window increases exposure, facili- tates flap insetting, eases vessel positioning, and minimizes perforating vessel torsion. 13 The external carotid artery is our recipi- ent vessel to minimize the risk of vascular spasm and arterial blockage. We prefer to use both the superficial and deep venous systems to reduce the risk of venous complications. The addition of the superficial venous system to the venae comitantes is an added safety measure to reduce the risk of flap congestion or loss because of septocutaneous venous compression when the flap is folded. The long vascular pedicle allows the cephalic vein to be used for a single large-caliber end-to-side anas- tomosis to the internal jugular vein. None of the patients were taken back for vascular spasm or venous congestion. The single-paddle folding technique positions the vascular pedicle over the mid dorsum of the nose, minimizing torsion or compression of the cutaneous perforators at the fold. This allows the ulnar portion of the flap, which is tolerant to fold- ing because of its subcutaneous and subdermal circulation, to be safely contoured three-dimen- sionally within the planned tip area. Vascular complications in nasal reconstruc- tion are of two types: extrinsic, at the anastomotic site; and intrinsic, related to flap insetting. Extrin- sic anastomotic complications are more easily managed because they are easily detected. Intrinsic complications are caused by twisting or stretching of the septocutaneous perforators, often caused by errors in design and insetting. Skin changes attributable to septocutaneous blockage are subtle, and a Doppler pulse may

remain even though the skin is not perfused. Intrinsic complications are more difficult to man- age because of constraints in pedicle length and flap repositioning. The two immediate flap losses were attribut- able to blockage of the skin perforators. In one patient, the radial artery was positioned too close to the tip, in the area of infolding of a two-plane repair. In a second patient, the perforators of a circumferential flap were compressed within the inset area. An additional buccal incision had not been used to maximize exposure. Although uneventful primary flap healing is routine, isolated partial necrosis of vault or colu- mellar lining occasionally occurs. Importantly, excess forearm skin of the folded flap can be hinged over from its external surface to fill this unexpected lining deficiency when the repair is resurfaced with a forehead flap. Partial superficial necrosis of the floor extension heals secondarily and has never required surgical débridement or skin replacement. Primary cartilage infections occur occasion- ally despite coverage of the dorsal cartilage graft within a folded well-vascularized skin flap. Graft infections are more common in irradiated fields, after previous failed repairs, or in patients with a history of infection. Although minor soft-tissue infection responds to antibiotic treatment, infec- tion of cartilage support grafts, which presents as increasing redness, pocketing, and cartilage expo- sure, requires early débridement and secondary late cartilage replacement. Methods other than the infolding technique have been described for microvascular nasal reconstruction. Burget and Walton used individ- ual radial island flaps, designed in tandem over the radial artery to line different parts of the lining defect. They skin-grafted their external surfaces, precluding initial dorsal support. 7 Dis- advantages include injury or torsion of individual septocutaneous perforators within these multiple paddles; multiple scars within the vault, floor, and columella; scar contracture; and a lack of excess skin to correct flap inset imperfections or salvage complications. The prelaminated microvascular forearm flap, described by Pribaz et al., prefabricates a “nose on the forearm” with cartilage and skin grafts. Later, the prefabricated tissues are transferred to the nasal defect. 5 Imperfect initial design and soft- tissue contracture may occur. Three-dimensional revisions to improve nasal shape or airway size are difficult because of scarring and limited excess tissue. Donor-site morbidity and inconvenience

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