Abstract
The case of a 25-year-old male with a facial gunshot wound is reported. A free fibula flap was performed for facial reconstruction. At 48 h after the operation, a thrombotic event was observed in the anastomosis. A distal arteriovenous (AV) fistula was performed to regulate the blood flow in the flap, and a combination of flaps (forehead flap and internal mammary artery perforator (IMAP) flap) was used for the skin defects. After creating the distal AV fistula, the blood flow was regulated and the free flap salvaged. No bone healing problem was observed in the free fibula flap and there were no complications related to the forehead and IMAP flaps. The fistula was patent at 2 years postoperative. Although all high-resistance flap conditions cannot be corrected with a distal AV fistula, the method presented in this case could be used as a last resort procedure for free flap salvage.
High velocity gunshot wounds can have devastating consequences, especially in the face, and can greatly affect an individual’s appearance. Three-dimensional reconstruction should be performed for injuries resulting in serious bone and soft tissue defects. The osteocutaneous free fibula flap (OCFF) plays a vital role in composite facial reconstruction, not the least because dental implants can be applied to it. Regional flaps can also be used in the face, especially for skin and soft tissue defects. The forehead flap and internal mammary artery perforator (IMAP) flap are favoured regional flaps for facial reconstruction. These flaps provide colour and tissue harmony with the face and are associated with minimal donor site morbidity.
However, even in the best hands, free flap surgeries may be accompanied by challenging complications such as postoperative thrombus at the anastomosis site, which can ultimately lead to flap failure. For this reason, free flap salvage procedures continue to be developed and discussed.
Flow dynamics are one of the important causes of postoperative vascular thrombus in free flap surgeries. If a high volume of blood enters a high-resistance flap, vascular flow dynamics become labile and may initiate a thrombus, possibly resulting in flap failure. In this situation, the affected flap can be salvaged and the blood flow can be balanced via an arteriovenous (AV) fistula at the distal arterial pedicle.
The case of a patient with a facial gunshot wound, who underwent facial reconstruction involving a combination of three flaps (OCFF, pedicled IMAP, and forehead flap) and a salvage procedure for the OCFF by distal AV fistula, is reported below.
Case report
A 25-year-old male was seen in the ER with a complex maxillomandibular–nasal defect due to a gunshot injury. There were no life-threatening problems except for the facial injury ( Fig. 1 ).
Three-dimensional computed tomography (3D CT) revealed panfacial fractures, maxillomandibular–nasal bone defects, and sequestrations ( Fig. 2 ). The patient was sent to the operating room for the extraction of non-viable bone fragments and soft tissues, and to maintain haemostasis. The mid-maxillary bone defect was reconstructed with titanium mesh in the shape of a nose. The panfacial fractures were fixated with both reconstruction plates and miniplates, and screws. The skin margins of the facial defects were sutured primarily. At the end of the operation there was a residual 7-cm bone defect from the left symphysis to the left angle of the mandible.
Three weeks later, the patient was returned to the operating room for reconstruction of the left mandibular defect. An osteocutaneous fibula flap was harvested from the right cruris and transferred to the defect. The bone length of the flap was 7 cm and the size of the skin island was 9 cm × 4 cm. The bone segment of the flap was fixated to the left mandibular defect with miniplates and screws. The skin island of the flap was sutured to the left submandibular area for reconstruction of the skin deficiency and flap monitoring. The right peroneal artery was anastomosed to the left superior thyroid artery, and one of the concomitant peroneal veins was anastomosed to the left superior thyroid vein in an end-to-end fashion using a 9–0 nylon suture. In addition, a left supratrochlear pedicled forehead flap was harvested and used to reconstruct the nasal base and upper lip defect. The donor area of the forehead flap was closed primarily and the OCFF donor area was skin-grafted.
At 48 h postoperatively, the patient was again returned to the operating room because of venous stasis in the skin island of the OCFF. During exploration, a mature thrombus was observed in the peroneal vein and no blood flow in the peroneal artery. Immediate thrombectomies were performed for both the artery and vein with 2F Fogarty catheters. The peroneal artery was anastomosed to the left facial artery in an end-to-end fashion because of the risk of rethrombosis. The peroneal veins were found still to be collapsed in spite of arterial inflow, whereupon the distal stump of the peroneal artery was anastomosed to the left facial vein in an end-to-end fashion forming a distal AV fistula. After this manoeuvre, periosteal arterial bleeding was observed in the neo-mandibular periosteum, but there was still no dermal bleeding in the skin island. As a result, the skin island was later discarded and the skin defect reconstructed with an IMAP flap. Twenty-one days after the last operation, the skin pedicles of the IMAP and the forehead flap were cut. No complications related to the IMAP or forehead flaps was encountered during the postoperative period.
Digital subtraction angiography (DSA) at 12 months postoperative revealed a patent distal AV fistula between the peroneal artery and the left facial vein ( Fig. 4 ). 3D CT revealed a healthy fibular bone at 18 months postoperative ( Fig. 3 ). The patient has now been followed-up for 2 years and is able to eat and speak ( Fig. 5 ).
