Clinical features of primary vein grafts in free tissue transfers

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.

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.

Reconstruction of Brachial Artery with Great Saphenous Vein Graft in A Case of Residual Soft Tissue Sarcoma Arm

Soft tissue sarcomas of the upper extremities are very rare tumors. Due to the complex anatomy of the arm, the management of the soft tissue sarcoma becomes very challenging for the operating surgeons. Nonetheless, a large portion of the patients can be treated in a limb-sparing manner ,if surgical expertises are present .We report a case of 30 years old lady with soft tissue sarcoma of right arm operated in an another hospital, came to our institute with pain in the operated site and positive histological margins. The patient had feeble radial and ulnar artery pulses. We had done a MR angiography of that limb and it showed no flow from mid arm level in the brachial artery, but presence of collaterals around elbow joint. We had removed the residual tumor and also excised 14 cm of right brachial artery. On opening the brachial artery, tumor thrombus was seen along the whole length of the excised segment. The defect was reconstructed with reverse great saphenous vein graft taken from left leg. Post-operative period was uneventful. Doppler ultrasonography done at 6 and 12 months later showed good flow in the grafted segment with minimal narrowing of the anastomosis sites.

Heparin-Eluting Electrospun Nanofiber Yarns for Antithrombotic Vascular Sutures

The surgical connection of blood vessels, anastomosis, is a critical procedure in many reparative, transplantation, and reconstructive surgical procedures. However, effective restoration of circulation is complicated by pathological clotting (thrombosis) or progressive occlusion due to excess cell proliferation that often leads to additional surgeries and increases morbidity and mortality risk for patients. Pharmaceutical agents have been tested to prevent these complications, but many have unacceptable systemic side effects. Therefore, an alternative approach to deliver these drugs at the site of injury in a controlled manner is necessary. The objective of this study was to develop electrospun nanofibers composed of polyester poly(lactide- co-glycolide) (PLGA), poly(ethylene oxide) (PEO), and positively charged copolymer, poly(lactide- co-glycolide)- graft-polyethylenimine (PgP) for electrostatic binding and release of heparin for application as an antithrombotic microvascular suture. PgP was synthesized with different coupling ratios between PLGA and branched polyethylenimine (bPEI) to obtain PgP₁ (∼1 PLGA grafted to 1 bPEI) and PgP_3.7 (∼3.7 PLGA grafted to 1 bPEI). Nanofiber yarns (PLGA/PEO/PgP₁ and PLGA/PEO/PgP_3.7) were fabricated by electrospinning. Heparin immobilization on the positively charged nanofiber yarns was visualized using fluorescein-conjugated heparin (F-Hep), and the amount of immobilized F-Hep was higher on both PLGA/PEO/PgP_3.7 and PLGA/PEO/PgP₁ than yarns without PgP (PLGA/PEO). We also found that F-Hep was released from both PgP-containing yarns in a sustained manner over 20 days, while over 60% of F-Hep was released within 4 h from PLGA/PEO. Finally, we observed that heparin-eluting nanofiber yarns with both PgP₁ and PgP_3.7 showed significantly longer clotting times than nanofiber yarns without PgP. The clotting time of PLGA/PEO/PgP_3.7 was not significantly different than that of free heparin (0.5 μg/mL). These results show that heparin-eluting electrospun nanofiber yarns may offer a basis for the development of microvascular sutures with anticoagulant activity.