The indications and reliability of vein graft use in free flap transfer

Comparisons of Impact of Vein Grafting with Different Indications on Outcomes of Reconstruction with Free Flaps

BACKGROUND

 Prior studies have shown an increased risk of complications and flap loss with the use of vein grafts in microsurgery. We hypothesize that indication for use of a vein graft can affect flap complications and loss rates.

METHODS

 We performed a retrospective review of all patients at our institution from 2010 to 2020 who underwent free flap reconstruction and required use of a vein graft. Indications for vein grafting included: salvage of flap during primary operation after microvascular compromise, augmentation of flow during primary operation, lengthening of the flap pedicle during the primary operation, and salvage of the flap during a secondary salvage operation after microvascular compromise.

RESULTS

 A total of 79 patients met the study inclusion criteria. There were significant differences among the vein graft indication groups and the following: area of reconstruction (p = 0.002), vein graft length (p = 0.018), vessels grafted (p = 0.001), vein graft donor site (p = 0.011), and total flap loss (p = 0.047). Of the four indications for vein grafting, salvage of the flap during secondary salvage operation after microvascular compromise had the highest rate of total flap loss (26.7%). There were no significant associations between other flap complications and vein graft indications.

CONCLUSION

 Vein graft use in the primary reconstructive setting is efficacious, with low risk of thrombosis. Use in secondary procedures, however, is associated with higher rates of total flap loss, likely due to the thrombotic process, which was initiated prior to the use of the graft resulting in the salvage procedure and not secondary to the graft itself.

Comparative study of arterial and venous grafting for pedicle lengthening in head and neck microvascular reconstruction

BACKGROUND

In the field of head and neck microvascular reconstruction, no previous study has compared arterial and venous grafting as methods of anterolateral thigh (ALT) pedicle lengthening. Therefore, we conducted this comparative study to compare the outcomes between the two pedicle lengthening techniques.

METHODS

We performed comparative effectiveness research by conducting a retrospective chart review from January 2012 to December 2021 to identify patients who underwent head and neck reconstruction with non-descending branch ALT perforator flaps using either the in situ pedicle lengthening (ISPL) technique or the vein graft (VG) technique. A total of 26 patients were analyzed, including 14 who underwent ISPL, and 12 who underwent VG. The collected data, including patient demographics, surgical indications, history of prior free flap, prior neck dissection, radiation therapy, chemotherapy, graft length, and flap outcomes, were analyzed. The flap outcomes were categorized as total flap loss, partial flap loss, flap compromise that required operating room visits, or minor issues, including infection or dehiscence. The flap characteristics and postoperative outcomes were compared between the two groups.

RESULTS

The VG group had two flap losses, whereas the ISPL group had none. Although the failure rate was higher in the VG group than that in the ISPL group, the difference was not statistically significant (0% vs. 16.7%, p = 0.203). Additionally, there were no significant differences in flap take-back (14.3% vs. 16.7%, p = 1) and minor complications between the two groups (35.7% vs. 33.3%, p = 1).

CONCLUSIONS

If pedicle lengthening with vessel graft is inevitable in head and neck reconstruction, arterial graft may provide a reliable outcome and may be considered an effective alternative when compared to vein grafts.

A Systematic Review of Microsurgical Pedicle Lengthening in Free Tissue Transfer

INTRODUCTION

Traumatic injuries that require free tissue flaps for reconstruction may require vascular pedicle extension between the flap and recipient vessels to form a clear anastomosis. Currently, a variety of techniques are used, each with their own potential benefits and harms. In addition, reports in the literature conflict on the reliability of pedicle extensions of vessels in free flap (FF) surgery. The objective of this study is to systematically assess the available literature about outcomes of pedicle extensions in FF reconstruction.

METHODS

A comprehensive search was performed for relevant studies published up to January 2020. Study quality was assessed using the Cochrane Collaboration risk of bias assessment tool and a set of predetermined parameters was extracted by 2 investigators independently for further analysis. The literature review yielded 49 studies investigating pedicled extension of FF. Studies meeting inclusion criteria underwent data extraction focusing on demographics, conduit type, microsurgical technique, and postoperative outcomes.

RESULTS

The search yielded 22 retrospective studies totaling 855 procedures from 2007 to 2018 in which 159 complications (17.1%) were reported in patients aged between 39 and 78 years. Overall heterogeneity of articles included in this study was high. Free flap failure and thrombosis were the 2 most prevalent major complications noted: vein graft extension technique had the highest rate of flap failure (11%) in comparison with the arterial graft (9%) and arteriovenous loops (8%). Arteriovenous loops had a rate of thrombosis of 5% versus 6% in arterial grafts and 8% in venous grafts. Bone flaps maintained the highest overall complication rates per tissue type at 21%. The overall success rate of pedicle extensions in FFs was 91%. Arteriovenous loop extension resulted in a 63% decrease in the odds of vascular thrombosis and a 27% decrease in the odds of FF failure when compared with venous graft extensions (P < 0.05). Arterial graft extension resulted in a 25% decrease in the odds of venous thrombosis and a 19% decrease in the odds of FF failure when compared with venous graft extensions (P < 0.05).

CONCLUSIONS

This systematic review strongly suggests that pedicle extensions of the FF in a high-risk complex setting are a practical and effective option. There may be a benefit to using arterial versus venous conduits, although further examination is warranted given the small number of reconstructions reported in the literature.

The role of vein grafts in reconstructive head and neck microsurgery

OBJECTIVE

Free tissue transfer is widely used for head and neck reconstruction. In certain circumstances, vein grafting is required to elongate free flap pedicles to connect them to appropriate recipient vessels. Because of controversy regarding the use of interposition vein grafts in free tissue reconstruction, this paper reports vein graft indications, techniques, safety, and outcomes for head and neck microvascular surgery.

METHODS

Twenty-six patients (23 men and 3 women) who underwent interposition vein grafting concurrent with free tissue transfer were included in this study. The most common reason for head and neck reconstruction with vein graft was tumor recurrence, followed by flap salvage. The interposition vein grafts were applied in two manners as temporary arteriovenous (A-V) loop and conduit to extend the length of the free flap for venous drainage.

RESULTS

The most common reconstructions were anterolateral thigh flaps (15 cases), followed by vastus lateralis myocutaneous (3 cases) and radial forearm (2 cases) flaps. The common recipient vessels were superior thyroid artery, superficial temporal artery and external jugular vein. The free flap loss rate was 7.7% with vein grafts and 4.9 without vein grafts (p = 0.380). The free flap complication rate was 50.0% and 16.8% in patients with and without vein grafts, respectively (p < 0.001). Radiation therapy, chemotherapy, prior neck dissection, and prior free flap transfer were more common in the vein graft group (all p < 0.001). The hospital stay was significantly longer for the vein graft group than for the non-vein graft group (29.5 vs. 19.0 days; p = 0.001).

CONCLUSION

Overall free flap survival rates of 92.3% and 95.1% in the vein and non-vein graft groups, respectively - indicating the reliability of the vein grafts in challenging head and neck reconstructions, particularly in salvage cases and patients with multiple reconstructions.

LEVEL OF EVIDENCE

Level 3.

Identification of the anatomy of the deep temporal vein using computed tomography imaging: A retrospective cross-sectional review of patient imaging

PURPOSE

The deep temporal vein (DTV) can be used in free flap procedures when the superficial temporal vein is inadequate. Despite its potential utility, its branching patterns have only been examined in one small anatomic study. The purpose of this study was to examine computed tomography angiography (CTA) images to determine DTV location, variation, and suitability as a microvascular recipient, to provide surgeons with a guide for its use in head and neck defects.

METHODS

A retrospective chart review identified 152 patient CTA images (76 female; 76 male) in a single academic center imaging database, selected consecutively from January 2017 to April 2020. Patients under 19 years were excluded; ages ranged from 19 to 80 years (average 51.6 years). Reason for imaging, DTV caliber, laterality, distance to zygomatic arch (ZA [coronal and sagittal]), distance to lateral orbital rim (LOR), and branching pattern were recorded.

RESULTS

The predominant reason for imaging was to rule out cerebrovascular accident (96.2%). Average caliber was 3.46 ± 1.29 mm (95% confidence interval [CI] [3.32, 3.61]; range, 1.00-10.8). Bilateral DTVs were observed in 98.7% of patients. Average distance to landmarks were as follows: ZA (coronal), 13.8 ± 5.85 mm (95% CI [13.2, 14.5]; range, 2.7-33.8); ZA (sagittal), 15.1 ± 6.12 mm (95% CI [14.1, 16.1]; range, 2.8-47.2); LOR, 47.1 ± 9.09 mm (95% CI [46.0, 48.1]; range, 10.8-62.9). Seven branching patterns were identified, including a posterior vertical variant that bypasses the superficial temporal fat pad.

CONCLUSIONS

The DTV is a "lifeboat" option for head and neck reconstruction. Its average caliber is sufficient for use in microsurgery. Knowledge of both its typical and aberrant courses allow for efficient preoperative planning and surgical dissection. CTA is a useful adjunct when planning to use the DTV for free tissue transfer.

Saphenous Vein Interposition Grafts in Lower Extremity Reconstruction: Appraisal of Technique and Case Series

Vascular microanastomosis is technically challenging in patients with calcified recipient and donor vessels. Inside-to-outside suturing can prevent plaque rupture and ensure full-thickness intimal approximation. Although this is the preferred technique for anastomosis of atherosclerotic vessels, direct connection of calcified arteries necessitates outside-to-inside suturing on one side of the anastomosis. Furthermore, it is difficult to achieve optimal vessel wall approximation in the setting of luminal size mismatch and rigid vasculature. We previously reported on the use of a saphenous vein interposition graft as a novel technique to achieve a flow-sparing anastomosis in patients with diffuse atherosclerosis who are undergoing free tissue transfer. This study further assesses outcomes of this technique in a series of patients and demonstrates a flap success rate of over 93% in patients with calcified recipient and donor microvasculature.

Vein Grafts in Free Flap Reconstruction: Review of Indications and Institutional Pearls

SUMMARY

Vein grafts enable soft-tissue reconstruction in cases of insufficient pedicle length, a lack of nearby recipient vessels, and a wide zone of injury caused by trauma or radiation therapy. The purpose of this article is to provide a comprehensive review of vein grafts in free flap reconstruction focusing on the timing of arteriovenous loops, complications, and surgical technique. Vein graft indications, types of vein grafts, and location-specific considerations are also reviewed. Three reconstructive microsurgeons at high-volume centers were asked to offer institutional pearls on the order of anastomosis, selection of donor veins, and timing of arteriovenous loops. In terms of gap length, vessel gaps less than 10 cm may be reconstructed with an interposition or transposition vein graft. For longer gaps, surgeons should consider the use of arteriovenous loops, transposition arteriovenous loops, or flow-through flaps. Both one and two-stage arteriovenous loops are used, depending on patient comorbidities, potential exposure of critical structures, and surgeon preference. Although one-stage arteriovenous loops expedite the reconstructive process, two-stage arteriovenous loops require shorter operations and help identify patients at risk of flap failure. Although whether the use of vein grafts increases flap failure rates is controversial, complications are highest in lower extremity reconstruction, cases of a prolonged interval between stages in two-stage arteriovenous loops, and unplanned vein grafts.

Overcoming severe calcified lower extremity artery in lower limb salvage operation by using the Fogarty catheter and vein graft

BACKGROUND

With severe vascular calcifications, vascular clamp application and utilizing the vessel for free flap recipient vessel becomes impossible. These obstacles can be overcome with the Fogarty catheter and vein graft.

PATIENTS AND METHODS

When unclampable artery was encountered intraoperatively, a vein graft was used to make a clampable recipient site for six diabetic foot patients (ages from 42 to 80). The end of the Fogarty catheter was inserted into the proximal end of the vein graft and the transected calcified vessel in sequence, and the balloon of the catheter was used as an intraluminal tourniquet. The remaining end of the vein graft was connected to the distal vessel with a vascular clamp.

RESULTS

Five short vein graft revascularization for segmental arterial occlusion, one long vein graft for recipient artery elongation was done (lengths from 2 to 13.8 cm). Three delayed, and two immediate anterolateral thigh flaps (sizes from 15 to 150 cm² ) were performed, and one patient received vein graft revascularization surgery only. Postoperative vascular sonography of all six patients showed well-maintained patency. Minor flap marginal disruption occurred at two patients but healed with conservative care. Postoperative follow-up was done for 1-18 months (average 7.17). Limb salvage was achieved for five patients and all five free flaps survived. However, for one patient, arterial restenosis at popliteal artery a month later lead to major amputation.

CONCLUSION

Using a Fogarty catheter and a vein graft may obtain perfect hemostasis during micro-anastomosis and achieve successful microvascular reconstruction in patients with severely calcified vessels.

REDV-modified decellularized microvascular grafts for arterial and venous reconstruction

Recently, a decellularized microvascular graft (inner diameter: 0.6 mm) modified with the integrin α4β1 ligand, REDV, was developed to provide an alternative to autologous-vein grafting in reconstructive microsurgery, showing good early-stage patency under arterial flow in rats. This consecutive study evaluated its potential utility not only as an arterial substitute, but also as a venous substitute, using a rat-tail replantation model. Graft remodeling depending on hemodynamic status was also investigated. ACI rat tail arteries were decellularized via ultra-high-hydrostatic pressure treatment and modified with REDV to induce antithrombogenic interfaces and promote endothelialization after implantation. Grafts were implanted into the tail artery and vein to re-establish blood circulation in amputated Lewis rat tails (n = 12). The primary endpoint was the survival of replants. Secondary endpoints were graft patency, remodeling, and regeneration for 6 months. In all but three cases with technical errors or postoperative self-mutilation, tails survived without any evidence of ischemia or congestion. Six-month Kaplan-Meier patency was 100% for tail-artery implanted grafts and 62% for tail-vein implanted grafts. At 6 months, the neo-tunica media (thickness: 95.0 μm in tail-artery implanted grafts, 9.3 μm in tail-vein implanted grafts) was regenerated inside the neo-intima. In conclusion, the microvascular grafts functioned well both as arterial and venous paths of replanted-rat tails, with different remodeling under arterial and venous conditions.