Evaluation of fibrin, cyanoacrylate, and polyurethane-based tissue adhesives in sutureless vascular anastomosis: a comparative mechanical ex vivo study

The stability of a microvascular anastomosis is an important prerequisite for successful tissue transfer. Advances in tissue adhesives are potentially opening new avenues for their use in sutureless microsurgical anastomosis, however they have not yet gained clinical acceptance. In this ex vivo study, a novel polyurethane-based adhesive (PA) was used in sutureless anastomoses and its stability compared with that of sutureless anastomoses performed with fibrin glue (FG) and a cyanoacrylate (CA). Stability was assessed using hydrostatic (15 per group) and mechanical tests (13 per group). A total of 84 chicken femoral arteries were used in this study. The time taken to create the PA and CA anastomoses was significantly faster when compared to the FG anastomoses (P < 0.001): 1.55 ± 0.14 min and 1.39 ± 0.06 min, respectively, compared to 2.03 ± 0.35 min. Both sustained significantly higher pressures (289.3 mmHg and 292.7 mmHg, respectively) than anastomoses using FG (137.3 mmHg) (P < 0.001). CA anastomoses (0.99 N; P < 0.001) and PA anastomoses (0.38 N; P = 0.009) could both withstand significantly higher longitudinal tensile forces compared to FG anastomoses (0.10 N). Considering the background of an in vitro study, the PA and CA anastomosis techniques were shown to be similar to each other and superior to FG, due to their stability and faster handling. These findings need to be validated and confirmed in further in vivo studies.

Conventional versus fibrin-glue-augmented arterial microanastomosis: An experimental study

The purpose of this experimental study was to develop an alternative technique of arterial microanastomosis using only 2 stay-sutures augmented with fibrin glue, and to compare it to the conventional technique in arteries of varying diameters mimicking hand arteries. Eight anastomoses were performed in 7 male rats, including 1 anastomosis each on the 2 femoral, iliac, and carotid arteries, and 2 on the subrenal aorta. The conventional technique was used on one side and on the first aorta anastomosis, while augmented anastomoses were performed on the other side and on the second aorta. Patency was tested 10 min after unclamping; clamping time, blood loss, anastomosis quality score (out of 15 points) and artery diameter were recorded. In arteries of diameter 0.5-2.2 mm, augmented anastomoses were on average 10.7 ± 3.2 min faster to perform (p &lt; 0.0001), with an average of 1.3 ± 0.9 g less blood loss (p &lt; 0.0001) and an average of 2.6 ± 2.5 points higher quality score (p &lt; 0.0001). There were no significant differences between the two techniques in terms of patency rate, regardless of artery size. However, 3 of the 7 augmented anastomoses were non-permeable in the femoral subgroup (i.e., submillimetric arteries). This straightforward technique appears to be time-saving and reliable, provided that the repaired artery is of sufficient size. Subject to clinical validation, this technique might help surgeons treating extensive hand wounds with multiple severed neurovascular bundles.

Utility of autologous fibrin glue in the donor site of free abdominal flap for breast reconstruction: A randomized controlled study

BACKGROUND

Seroma formation at the donor site is a common complication of breast reconstruction using free abdominal flap. In this study, we assessed the benefits of use of autologous fibrin glue (AFG) at the donor site.

METHODS

This randomized controlled study compared AFG group (n = 61) with commercial fibrin glue (CFG) group (n = 79). Owing to the high volume of AFG (10 mL), AFG group received fibrin glue at both the anastomosis and the donor sites, whereas CFG group received fibrin glue only at the anastomosis site. Operative protocols and the criteria for postoperative drain removal were identical in both groups. Patient characteristics and abdominal discharge were compared between the two groups.

RESULTS

Since anemia was a contraindication for use of AFG, preoperative Hb in CFG group was significantly lower than that in AFG group; other factors were comparable in the two groups. The mean total abdominal drain volumes on first postoperative day (POD1) and POD2 was (AFG vs. CFG) 130.9 vs. 169.4 mL (P < 0.001) and 131.0 vs. 162.8 mL (P = 0.03), respectively. On POD3, there was no significant difference in this respect (116.2 vs. 128.4 mL, P = 0.19). The mean time for removal of all abdominal drains was significantly lower in AFG group (7.4 vs. 8.4 days; P = 0.01).

CONCLUSIONS

AFG reduced the discharge at the donor site of free abdominal flap, especially in the early postoperative period. AFG helped to reduce the abdominal drainage period.

Endothelial inflammatory and thrombogenic expression changes in microvascular anastomoses - An immunohistochemical analysis

The aim of this study was to investigate intraluminal vessel diameters and endothelial expression levels of pro-inflammatory and -thrombotic mediators in patent and non-patent microvascular anastomoses. Endothelial expression of CD31, VCAM-1, E- and P-Selectin, eNOS, iNOS and PAI-1 was evaluated by immunohistochemistry and compared to non-anastomosed arteries as controls. Intraluminal diameters were determined via H.E.-staining. In 20 human anastomoses (8 patent, 12 non-patent) neither the analysis of endoluminal de-endothelialization (p = 0.966) nor luminal narrowing (p = 0.750) revealed any significant differences between patent and non-patent microanastomoses. Expressions of pro-inflammatory mediators were significantly higher in patent anastomoses compared to controls but did not show any difference compared to non-patent anastomoses (p > 0.050). iNOS was higher in non-patent compared to patent anastomoses (p = 0.030) and controls (p = 0.001), whereas eNOS did not reveal any differences between these groups (p = 0.611 and p = 0.130). In non-patent anastomoses PAI-1 was expressed higher compared to patent anastomoses and controls (p = 0.021 and p < 0.001). Irrespective of their patency, anastomoses are characterized by endothelial dysfunction with a pro-inflammatory and pro-thrombotic milieu. Avoiding endothelial trauma during suturing is essential in order not to aggravate existing endothelial dysfunction in microanastomoses. Additionally, the influence of medication-related changes on anastomoses should be investigated as this is still an indistinctive topic.

Non-suturing microvascular anastomosis in maxillofacial reconstruction- a comparative study

AIM

The aim of the study is to compare the advantages and disadvantages of non-suturing anastomotic methods over conventional microsuturing for microvascular venous anastomosis.

MATERIALS AND METHODS

All patients reporting to the institute for hard and soft tissue reconstruction (Primary/secondary) were enrolled in the study. Patients with systemic comorbidities, peripheral vascular diseases, or anatomical aberration of the indicated donor site were excluded from the study. The patients selected for the study were randomly allocated to five groups of different techniques of venous anastomosis, namely Group I (conventional microsuturing), II (fibrin sealant reinforced microsuturing), III (couplers), IV (staplers), V (Laser Assisted Vascular Anastomosis (LAVA)). Intraoperative anastomotic time, flap ischaemic time, patency and leakage were the parameters that were assessed for all five groups.

RESULTS

80 Patients were randomly allocated to five groups and each group comprised 16 patients. The mean ischaemic time and standard deviation of Group I and Group II were 256.19 ± 10.622 min and 255.19 ± 11.083 min, and for groups III, IV, and V were 193.38 ± 9.972 min, 139.06 ± 6.413 min, and 139.31 ± 6.364 min respectively (p < 0.001). Mean anastomotic time and standard deviation were 19.813 ± 1.5366 min in Group I and 20.281 ± 1.6514 min in Group II. The non-sutured anastomosis groups III, IV, and V showed a mean anastomotic time of 5.375 ± 0.9876 min, 4.175 ± 0.7664 min, and 3.856 ± 0.867 min respectively (p value < 0.001). In Groups I and II, 18.8% of patients had delayed patency and in Groups III, IV and V, immediate patency was observed in all subjects (p value 0.030). In Groups I and II, 18.8% and 6.3 % of patients respectively had leakage, whereas all patients in Groups III, IV, V had no leakage from the anastomotic site (p value 0.119).

CONCLUSION

Based on the results of the study, non-suturing techniques should be preferred over microsuturing technique whenever appropriate for venous anastomosis.

The Importance of Serological Procalcitonin Levels After Autologous Microsurgical Transplantation

INTRODUCTION

Published data on procalcitonin (PCT) levels after microsurgical interventions are very scarce, although infection within these patients is not only associated with severe morbidity but also significantly higher mortality rates.

MATERIAL AND METHODS

Retrospective study on 20 patients, who were operated on by a single experienced plastic and reconstructive surgeon within one year (June 2017-June 2018). The authors included all patients, who received microvascular transplants for reconstruction of soft tissue defects. Furthermore, age above 18 years and appropriate documentation allowing sufficient data collection were defined as inclusion criteria. The authors excluded all patients with perioperative systemic inflammation and transplant loss, as our aim was to solely determine and evaluate potential alterations of serological PCT levels after microsurgical interventions.

RESULTS

The PCT cutoff level to differentiate physiological and pathological levels was defined as 0.1 μg/L. There was no detectable increase in procalcitonin in all of our 20 patients, for whom the authors performed microvascular transplantation to reconstruct soft tissue defects.

CONCLUSION

Serological PCT levels remain stable after the considered surgical interventions and therefore PCT levels might be utilized to identify systemic inflammation, thus helping to reduce severe complications by early individualized antiinfective treatment strategies.