Interposition Vascular Grafts Research Articles

Diversity of the free helical rim flap: A case series tailoring the microsurgical technique to esthetically optimize full-thickness nasal defect reconstructions

The free helical rim (FHR) flap offers like-with-like reconstruction for full-thickness nasal defects. A case series of nasal reconstruction using an FHR flap was presented, detailing surgical steps and refinements, as well as functional and esthetic outcomes. This is a retrospective cohort study of composite nasal defect reconstruction with FHR flap from August 2018 to March 2020. Descriptive data were analyzed by SPSS software. Six cases were recruited, four were unilateral alar defects, one was hemi-nose, and one was ala plus tip. The average size of the defect was 2.5×2.8cm2. Three FHR flaps were designed with retrograde pedicles and three with anterograde pedicles. The facial artery and veins were the recipient vessels in all cases. Vascular grafts were used in all six cases. Descending branch of the lateral circumflex femoral (DLCxF) artery and vein functioned as interposition vascular conduits in five cases. Superficial forearm vein grafts were used in one case. One patient needed flap re-exploration due to venous congestion. One patient had partial flap necrosis due to delayed infection, and one developed delayed wound dehiscence in the irradiated wound. The average follow-up was 18 months. The FHR flap has consistent vascular anatomy. It can be raised as an anterograde or retrograde flap for a contralateral or ipsilateral inset. FHR flap can be used in extensive composite nasal defects. This case series demonstrates that interposition vascular grafts are invariably needed and the possibility of using forearm vessels as grafts instead of DLCxF artery and vein.

Salvage Procedures for Facial Reanimation With Neurovascular Flaps When Previous Surgeries Failed: Is Homolateral Vessel or Nerve Depletion a Contraindication?

Facial paralysis reconstruction can be difficult in extensive defects after complex facial or cranial base tumor resection and radiotherapy or when primary smile reanimation attempt has failed. The surgical challenge is more complicated when defects are associated with recipient vessels or nerves depletion. This scenario has not been well described in the literature, and the present article will address the alternatives that plastic surgeons may use in these circumstances. Seventy-five patients operated in the Hospital Gregorio Marañon between 2008 and 2020, for dynamic reconstruction of facial paralysis, were retrospectively evaluated, collecting data about previous facial nerve surgeries, radiotherapy, chemotherapy, recipient nerve for motor restoration and vessels used for free flaps, type of neurovascular free flap (NVFF), and functional score before and after the facial reanimation surgery. Patients presenting recipient vessel and/or nerve depletion after several facial surgeries requiring a variation from the common NVFF surgical protocol were included in this study. Six cases (8%) with facial paralysis and absent recipient homolateral vessels or nerves after severe cranial base surgery, parotid malignancies, or schwannoma surgery were included. Two patients had an immediate functional reconstruction during the oncologic resection surgery, and 4 patients had a delayed reconstruction. Three patients had previous reconstruction with free flaps, and the vascular pedicles of previous flaps were used for the new NVFF. In the other 3 cases, interposition vein grafts to the contralateral recipient vessels were required to perform NVFF. Masseteric nerve in 4 cases, hypoglossal nerve and posterior branch of the deep temporal nerve in 1 case each, were used as recipient nerves. House-Brackmann score improved in all patients after surgery. Neurovascular free flap can be successfully performed to restore facial motion after depletion of homolateral recipient vessels or nerves after previous facial or cranial base surgeries. In these cases, interposition vascular grafts or the pedicle of previous flaps are essential to provide vascularization as well as an optimal orientation of flaps, to reach recipient nerves in a 1-step procedure.

Large anterior tibial artery pseudoaneurysm as a rare complication to vascular surgery

A pseudoaneurysm is a rare complication to vascular reconstruction and may be limb threatening if not treated. A patient previously treated for an aneurysm of the left popliteal artery presented to our outpatient clinic with swelling and reduced active movement. Computed Tomography Angiography revealed an 8.1 cm large pseudoaneurysm of the anterior tibial artery (ATA). The pseudoaneurysm was successfully treated with an interposition vascular graft to the patent ATA. Open surgical repair was the only option with resection of the pseudoaneurysm and insertion of an interposition vascular graft with and end-to-side anastomosis. The giant ATA pseudoaneurysm was successfully treated with insertion of a new end-to-side graft anastomosis with interposition to the old patent vascular graft.

Characteristics and outcomes of primary interposition vascular grafts in free flap breast reconstruction

There is paucity of data on primary interposition vascular grafts (IVG) use in microsurgery. Our study examines the characteristics, indications and outcomes of IVG in free flap breast reconstruction. All cases of breast reconstruction with free flaps between January 2013 and June 2018 were examined and cases with primary IVG were included. Data were collected on patient, flap and graft characteristics, indications and outcomes. A total of 76 IVG, specifically 65 vein grafts and 11 arterial grafts, were used for 49 (of 1547) flaps in 48 (of 1346) cases. Of these, 52 grafts were primarily used to lengthen the pedicle and aid flap inset and 24 grafts to augment venous flow; 49 grafts were harvested from the flap harvest site, 7 from the anastomosis recipient site and 20 from a separate site. Of the total, 16.7% (8/49 flaps) required salvage procedures - seven cases for venous congestion and one for ischaemic compromise - in comparison to 4.3% in cases without IVG (65/1498) (p<0.0001). Out of 49 IVG flaps, three (6.1%) failed in comparison to 1.7% (26/1498), where IVG flaps were not used (p<0.05). Two were transverse upper gracilis flaps with vessel calibre mismatch, and one lumbar artery perforator (LAP) flap with past infected implant and failed deep inferior epigastric artery (DIEP). We present the largest number of primary vascular grafts for free flap breast reconstruction in the literature. Primary IVG were used for at-risk flaps and had a success rate of 93.9%. This shows that IVG are a viable option to prevent venous congestion and lengthen the pedicle to aid inset and shaping; they are associated with higher complication rates bearing in mind the high-risk profile of the flaps these are used for.

Usability of Inferior Vena Cava Interposition Graft During Living Donor Liver Transplantation: Is This Approach Always Necessary?

PurposeTo share the outcome of caval reconstruction technique in patients who underwent living donor liver transplantation (LDLT) with inferior vena cava (IVC) interposition grafting. MethodsBetween January 2009 and December 2018, an artificial or homologous interposition vascular graft was used for the continuity of resected native (IVC) due to various reasons in 29 of 1740 patients who underwent LDLT at our institute. Demographic, clinical, and radiological data were prospectively collected and retrospectively analyzed. ResultsSixteen female and 13 male patients ranging 6–67 years of age were included. Right, left, and left lobe lateral segments were used in 22, 5, and 2 patients, respectively. The three leading LDLT indications were primary or idiopathic Budd-Chiari syndrome (BCS) (n = 12), alveolar echinococcosis (n = 7), and secondary BCS (n = 5). The three leading indications for IVC interposition grafting were thrombosis, dense fibrosis, and IVC invasion caused by tumor or echinococcosis. Homologous IVC graft was used in 17, homologous aortic graft in 7, and Dacron graft in 5 patients. Throughout the follow-up period, ascites ± pleural effusion and elevated liver enzymes were detected in 12 and 4 patients, respectively. Stenosis and/or thrombosis requiring one or more procedures such as 1–6 sessions balloon angioplasty, stent, and thrombus aspiration were observed in half of the patients. ConclusionRetrohepatic IVC damages are not a contraindication for LDLT. The presence or absence of venous collateral circulation is an important indicator of the need for IVC interposition graft use.

Acquired Tracheoesophageal Fistula in Infancy and Childhood

Acquired tracheoesophageal fi stula in infancy and childhood is a very rare condition with no epidemiological data available in the literature for it. There is a huge similarity of the condition to the congenital acquired tracheoesophageal fi stula. Management of children with this condition can be diffi cult with a high risk of complication. To provide a successful management of the condition, there are some points that need to be addressed about acquired tracheoesophageal fi stula. In this report, the author presents fourteen different cases of acquired TEF with diff erent etiologies over 11 years (2006 - January 2017) who were referred for management to tertiary care hospital in Jeddah, KSA; all patients had removal of the foreign body followed bysurgical repair of the fi stula. This report describes the detailed steps of our surgical repair, including the approach to the fi stula and the type of repair pointing out the importance of removal of the scar tissue anduse of interposition vascular grafts with suture lines separation. This study presents our experience in management and surgical repair of the acquired tracheoesophageal fistula.

The trap-door technique for coronary reimplantation in aortic root surgery.

Coronary ostia reimplantation is a crucial stage of every aortic root replacement procedure. The 'button technique' is currently the most used method and it has shown satisfactory outcomes over time. However, coronary reimplantation techniques still present drawbacks such as pseudoaneurysm formation, kinking, bleeding and coronary dehiscence, especially when coronaries are hard to mobilize. We adapted the trap-door technique, commonly used in the arterial switch operations, in order to apply it in older patients requiring an aortic root replacement procedure. The key passage of such a technique is the creation of an L-shaped trap-door flap in the conduit graft in order to produce a cone-like extension of the conduit from which the coronary ostium can arise. We applied this technique in 24 patients over 8 years and we did not experience any complication related to coronary ostia reimplantation. In conclusion, we think that this method could be considered as an alternative technique in order to avoid the use of an interposition vascular graft or a pericardial patch when the conventional reimplantation techniques are not feasible.

Reply

Sir: We thank Drs. Sapountzis and Chen for their attention to our previous article regarding partial nasal reconstruction with vascularized auricular flaps.1 In order to avoid the interposition vascular grafts, the authors harvested the retrograde flow flap from the contralateral side and used the ipsilateral temporal superficial vessels as the recipient vessels. We agree that their modification might have the benefits they described in the letter. However, in the figures they provided, the flap seems to be only a soft-tissue flap and not the composite flap with auricular cartilage we usually harvest. Since the nasal defect was not shown in those figures, we could not judge which nasal subunit was involved in this case from the shape of that flap. We are very interested to know, in the case of a full-thickness nasal defect, whether the contralateral preauricular flap could repair the three-dimensional deformity. As we wrote in the article,1 our nasal reconstruction goal is not to “fill holes” but rather to restore delicate three-dimensional structures. The helical rim, especially the helical root, offers the best match in terms of shape, texture, and color when reconstructing nasal ala. It also provides all three layers, as skin, cartilaginous framework, and lining, which are necessary for both functional and aesthetic purposes. In our practice, the majority of the defects involved nasal alae, and we found the retrograde flow flaps were optimal for ipsilateral defects with particular concerns on pedicle insetting and nasal ala shaping. In this situation, no matter which recipient vessels—the ipsilateral facial or superficial temporal vessels—were used, the interposition vascular grafts were needed. Apparently this is just opposite to Drs. Sapountzis and Chen’s method. In addition, since the superficial temporal vascular system is a versatile option for facial reconstruction,2 we would like to save one side for potential use rather than destroy both sides in one operation. In conclusion, we appreciate the opportunity to discuss the technique viewpoints raised by our article. Drs. Sapountzis and Chen’s suggestion also could be an alternative in certain cases. DISCLOSURE The authors have no financial interest to declare in relation to the content of this communication. Danru Wang, M.D. Yunliang Qian, M.D. Department of Plastic and Reconstructive Surgery Ninth People’s Hospital Shanghai Jiao Tong University School of Medicine Shanghai, People’s Republic of China

Use of fibula pedicle as a composite interposition vascular graft to salvage large skin paddle with anomalous vascular supply

We report a case of free fibula osteomyocutaneous flap whose skin paddle had a dominant blood supply from a soleus musculocutaneous perforator which originated in the posterior tibial artery in addition to contribution from the peroneal septocutaneous perforators and was managed by two sets of anastomosis on either side of the neck, one for the peroneal vessels and the other for the dominant musculocutaneous perforator. The second anastomosis was achieved by using the excess length of the flap pedicle vessels (peroneal) as composite (both artery and vein) autologous interposition vascular graft to reach the opposite side of the neck.

Coils and tubes releasing heparin. Studies on a new vascular graft prototype

Coiled metallic guidewires find widespread use, for instance in interventional cardiology. It is known that release of heparin from the surface of guidewires is advantageous to prevent formation of thrombotic emboli. New coiled tubular structures, having larger inner and outer diameter as compared to guidewires, are presented. In theory these tubes can be used as interposition vascular grafts. Ten coiled tubes with an internal diameter of 690 μm were made. Five different adherent polymeric coatings with increasing hydrophilicity were used. Five tubes contained heparin in the coating and the other five were unheparinised controls. The five tubes containing heparin were studied with respect to heparin release in vitro (amount released, kinetics), and immobilised heparin that is exposed at the surface. All tubes were studied with a direct cell contact assay using 3T3 mouse fibroblast cells, a dynamic thrombin generation test, and endothelial cell growth onto the coils. It was found that the heparinised tubes lead to very little thrombin formation. It is argued that this is due to heparin that is immobilised and exposed at the inner surface of such tubes. Furthermore the coils showed to be cytocompatible and endothelial cells adhere and proliferate well onto the coils. This concept is believed to hold promise for further development of small vascular grafts.

Perivascular graft heparin delivery using biodegradable polymer wraps

Heparin remains the gold-standard inhibitor of the processes involved in the vascular response to injury. Though this compound has profound and wide-reaching effects on vascular cells in culture and animal models, its clinical utility has been questionable at best. It is clear that the mode of heparin delivery is critical to its potential and it may well be that routine forms of administration are insufficient to observe benefit given the heparin's short half-life and complex pharmacokinetics. When ingested orally, heparin is degraded to inactive oligomer fragments while systemic administration is complicated by the need for continuous infusion and the potential for uncontrolled hemorrhage. Thus alternative heparin delivery systems have been proposed to maximize regional effects while limiting systemic toxicity. Yet, as heparin is such a potent antithrombotic compound and since existing local delivery systems lack the ability to precisely regulate release kinetics, even site-specific therapy is prone to bleeding. We now describe the design and development of a novel biodegradable system for the perivascular delivery of heparin to the blood vessel wall with well-defined release kinetics. This system consists of heparin-encapsulated poly( dl lactide- co-glycolide) (pLGA) microspheres sequestered in an alginate gel. Controlled release of heparin from this heterogeneous system could be obtained over a period of 25 days in vitro. The experimental variables affecting heparin release from these matrices were investigated. Gel permeation chromatography (GPC) and scanning electron microscopy (SEM) were used to monitor the degradation process and found to correlate well with the release kinetics. Heparin-releasing gels inhibited growth of bovine vascular smooth muscle cells in tissue culture in a dose-dependent manner. Moreover, gel release controlled vascular injury in denuding and interposition vascular graft animal models of disease even when uncontrolled bleeding was evident with standard matrix-type release. This system may therefore provide an effective means of examining the effects of various compounds in the control of smooth muscle cell proliferation in accelerated arteriopathies and also shed light on the biologic nature of these processes.

Duplex ultrasound analysis of operated carotid arteries in baboons.

Duplex ultrasound analysis, which combines high-resolution B-mode imaging and Doppler spectral flow analysis, was used to examine 3 to 4 mm in diameter normal [n = 24] and mechanically manipulated baboon carotid arteries (endarterectomies [n = 10], construction of interposition vascular grafts [n = 10], and placement of endovascular stents within interposition grafts [n = 4]). Patency or occlusion was definitively confirmed by direct visualization and palpation during surgical exploration at defined intervals or by postmortem histologic examination. Duplex examination accurately demonstrated postoperative hemodynamic changes and with only one exception correctly identified patency and occlusion. We conclude that this technique is superior to more invasive methods for verification of the outcome of operations on small arteries in experimental animals.