Good visualization is a prerequisite for performing microvascular anastomosis. The most commonly used dye, methylene blue, has several limitations: it is washed off quickly and stains all the vessel layers. The objective of our study is to use 2 new novel dyes for improving visualization.
After ethical committee approval, 2 Dyes (2% cresyl violet, 1% eosin) were studied in 3 groups, 20 rats in each group and 5 rats in the combined group. End-to-side anastomosis was performed in the classic fashion in 45 rats. After venotomy, the dye was applied to the raw surface of the vessels and subsequently, anastomosis was performed. The improvement in visualization was judged by 3 blinded experts and nonexperts in 4 groups on a scale of 1-10. Scores were statistically analyzed. After 2 weeks, animals were re-explored to check the delayed patency, and segments were harvested for histopathologic analysis.
The immediate and delayed patency rates were 100% (45/45) and 97% (33/34), respectively. In statistical analysis, the combined group (P = 0.005)was judged statistically significant because of the contrast in color. All the layers were stained by both dyes, staining lasted until the end of the surgery. Visibility of the cut ends was better in cresyl violet. All histopathologic findings suggested normal changes at the anastomotic site.
This study showed that the use of these 2 dyes was not only feasible but highly efficacious. Even though all the layers were stained by both the dyes, the visibility of the cut ends was better. In both dyes, staining lasted until the end of surgery. To the best of our knowledge, this is the first study that has used these 2 novel dyes to improve visualization in microvascular anastomosis in an experimental setting.

UNASSIGNED: Analyze efficacy of self-directed resident microvascular training versus a mentor-led course.
UNASSIGNED: Randomized, single-blinded cohort study.
UNASSIGNED: Academic tertiary care center.
UNASSIGNED: Sixteen resident and fellow participants were randomized into two groups stratified by training year. Group A completed a self-directed microvascular course with instructional videos and self-directed lab sessions. Group B completed a traditional mentor-led microvascular course. Both groups spent equal time in the lab. Video recorded pre and post-course microsurgical skill assessments were performed to assess the efficacy of the training. Two microsurgeons, blinded to participant identity, evaluated the recordings and inspected each microvascular anastomosis (MVA). Videos were scored using an objective-structured assessment of technical skills (OSATS), a global rating scale (GRS), and quality of anastomosis scoring (QoA).
UNASSIGNED: The pre-course assessment identified that the groups were well matched with only \"Economy of Motion\" on the GRS favoring the mentor led group (p = .02). This difference remained significant on the post assessment (p = .02) Both groups significantly improved in OSATS and GRS scoring (p < .05). There was no significant difference in OSATS improvement between the two groups (p = .36) or improvement in MVA quality between groups (p > .99). Time to completion of MVA significantly improved overall by a mean of 8 min and 9 s (p = .005) with no significant difference between post training times to complete (p = .63).
UNASSIGNED: Different microsurgical training models have previously been validated as effective methods for improved MVA performance. Our findings indicate that a self-directed microsurgical training model is an effective alternative to a traditional mentor driven models.
UNASSIGNED: Level 2.

BACKGROUND: Severe aqueous tear deficiency is caused by primary or secondary main lacrimal gland insufficiency. The transplantation of a human lacrimal gland could become a potential treatment option to provide physiological tears with optimal properties. To this end, we performed an ex vivo study to develop a surgical strategy that would ensure a vascular supply for a lacrimal gland transplant using microvascular techniques.
METHODS: Five cadaver heads were used to perform a lateral orbitotomy in order to identify the vascular pedicle and the lacrimal gland itself. The principal feasibility and the time of the required surgical steps for an intraorbital microvascular re-anastomosis of the human lacrimal gland were documented. Patency and potential leakage of the anastomosis were tested with hematoxylin intraoperatively. Postoperatively, routine histological, as well as scanning electron microscopy (SEM) of the gland and vascular anastomosis, were performed.
RESULTS: The vascular pedicle of all five glands could be isolated over a minimum stretch of at least 1 cm, severed, and successfully reanastmosed microsurgically. Time for arterial anatomization (n = 4) was 23 ± 7 min and 22 ± 3 min for the vein (p = 0.62). The total time for the entire microvascular anastomosis was 46 ± 9 min. All anastomosis were patent upon testing. SEM revealed well-aligned edges of the anastomosis with tight sutures in place.
CONCLUSIONS: Our study demonstrates as proof of principle the feasibility of intraorbital microvascular re-anastomosis of a human lacrimal gland within the presumed window of ischemia of this tissue. This should encourage orbital surgeons to attempt lacrimal gland transplantation in humans in vivo.

BACKGROUND: Microsurgical anastomosis is technically difficult especially for less-experienced surgeons. Traditionally, surgeons in training could only accomplish these surgeries under intensive guiding and supervision from senior surgeons. This study presents and characterises a new method for microsurgical trainees to objectively evaluating the quality of vascular anastomosis intraoperatively.
METHODS: We conducted a prospective study to determine the utility of patency test of vascular anastomosis with assistance of high-speed video recording (PTHVR) to evaluate the quality of vascular anastomosis during microsurgery. To determine whether the use of PTHVR outperformed traditional supervision from senior surgeons (historical control), we compared the outcomes of microsurgeries including free flap transfer and replantation between the two groups.
RESULTS: A total of 211 patients were enrolled, of which 98 underwent surgery under traditional supervision and 113 underwent surgery with PTHVR. Of the 211 patients, 102 underwent digit replantation (48%), 22 underwent limb replantation (10%), and 87 underwent free flap transfer (42%). There was no statistical difference between the two groups in age, gender, BMI, pre-existing comorbidities, smoking status, alcohol consumption, and duration of surgery. Use of PTHVR as an intraoperative guide significantly decreased the rate of re-exploration surgeries (PTHVR, 8.0% [9/113]; control, 23.5% [23/98]; P = 0.002) and replantation/free flap failures (PTHVR, 8.8% [10/113]; control, 19.4% [19/98]; P = 0.029) compared with historical control under traditional supervision.
CONCLUSIONS: PTHVR is a useful tool for improving the success rate of microsurgery for less-experienced surgeons when compared with traditional supervision mode.

Background: Compared with the conventional microvascular anastomosis method, the back wall technique and untied stay suture method allow for better visualization of the vascular lumen and have been reported to be effective for beginner surgeons. However, there are no reports of such advantages from experimental studies. The present study compared the usefulness of the conventional method (Method C), back wall technique (Method B), and untied stay suture method (Method U) in rats. Methods: Ninety end-to-end anastomosis procedures of the right femoral artery and vein were performed in rats. The anastomosis condition was assessed at the completion of suturing one side, at the completion of vascular anastomosis, and on postoperative day 7. Results: After suturing one side, suture errors were observed in three veins with Method C. Immediately after the completion of vascular anastomosis, blood flow was impaired in one vein with Method C. On postoperative day 7, blood flow was impaired in one artery and one vein with Method C, one vein with Method B, and one artery with Method U. Conclusions: No significant differences were observed between back wall technique and the untied stay suture method. However, the conventional method was more likely to lead to suture error or impaired blood flow compared with back wall technique and the untied stay suture method.

BACKGROUND: The Exoscope is a novel high-definition digital camera system. There is limited evidence signifying the use of exoscopic devices in microsurgery. This trial objectively assesses the effects of the use of the Exoscope as an alternative to the standard operating microscope (OM) on the performance of experts in a simulated microvascular anastomosis.
METHODS: Modus V Exoscope and OM were used by expert microsurgeons to perform standardized tasks. Hand-motion analyzer measured the total pathlength (TP), total movements (TM), total time (TT), and quality of end-product anastomosis. A clinical margin of TT was performed to prove non-inferiority. An expert performed consecutive microvascular anastomoses to provide the exoscopic learning curve until reached plateau in TT.
RESULTS: Ten micro sutures and 10 anastomoses were performed. Analysis demonstrated statistically significant differences in performing micro sutures for TP, TM, and TT. There was statistical significance in TM and TT, however, marginal non-significant difference in TP regarding microvascular anastomoses performance. The intimal suture line analysis demonstrated no statistically significant differences. Non-inferiority results based on clinical inferiority margin (Δ) of TT=10 minutes demonstrated an absolute difference of 0.07 minutes between OM and Exoscope cohorts. A 51%, 58%, and 46% improvement or reduction was achieved in TT, TM, TP, respectively, during the exoscopic microvascular anastomosis learning curve.
CONCLUSIONS: This study demonstrated that experts\' Exoscope anastomoses appear non-inferior to the OM anastomoses. Exoscopic microvascular anastomosis was more time consuming but end-product (patency) in not clinically inferior. Experts\' \"warm-up\" learning curve is steep but swift and may prove to reach clinical equality.

We previously developed a device for end-to-end anastomosis powered by negative pressure and demonstrated that using the device allow the operator to anastomose semi-automatically with little stress. Here, we sought to build a device for and demonstrate that negative pressure can also be used in end-to-side anastomosis which is clinically popular as end-to-end anastomosis through animal experiment using rats.The devices were constructed with a laser lithographic/3D-printing machine. Nine SD rats were used. Each of the nine rats underwent end-to-side anastomosis between the superficial epigastric vein and the femoral vein using the device. Rat was anesthetized one week later and the anastomotic site was inspected through operative microscope for patency. The anastomotic site was harvested with the device and the rat was euthanized. The anastomotic site was embedded in epon, sectioned, stained with toluidine blue, and analyzed with light microscopy. Eight of the nine anastomoses were patent immediately after the procedures, and two of the nine were patent at 1 week after the procedures. In the failed cases, the vessels dislocated from the device because the clamps loosened during the observation period after the operation. The experiments have shown that the device using negative pressure can also be applied to end-to-side microvascular anastomosis. The patency rate is low and further improvement is required.

Finger revascularization has been performed without a microscope in limited-resource environments only when absolutely necessary. This experimental study sought to assess the feasibility of microvascular anastomosis in rats performed using loupes or smartphone magnification. Thirty rats were divided into three groups of 10 individuals according to the magnification method used: operating microscope (control group M), surgical loupes (group L) and smartphone (group S). The infrarenal aorta was dissected under a microscope, then anastomosed by interrupted sutures using the group-specific magnifying device. The main analytical criteria were vessel diameter, anastomosis duration, immediate flow patency (T0), patency after one hour (T1) and anastomosis quality. Anastomosis duration was comparable between groups M and L, but was twice as long in group S. The number of leaks at clamp removal was higher in group S. Patency rates at T0 and T1 were 100% in groups M and L, but were significantly lower in group S. The anastomosis quality was low in group L and poor in group S. Anastomosis of digital arteries using loupes is possible, but the resulting quality is lower than with a microscope. Current smartphones are not adequate for performslt ing microvascular repairs in a living model.

The introduction of microvascular free flaps has revolutionised modern reconstructive surgery. Unfortunately, access to training opportunities at standardised training courses is limited and expensive. We designed a pilot study on microvascular anastomoses with the aim of verifying if a short course, easily reproducible, could transmit microvascular skills to participants; if the chosen pre-test was predictive of final performance; and if age could influence the outcome. A total of 30 participants (10 students, 10 residents and 10 surgeons) without any previous microvascular experience were instructed and tested during a single 3 to 5 hour course. The two microanastomoses evaluated were the first ever performed by each participant. More than the half of the cohort was able to produce both patent microanastomoses in less than 2 hours; two-thirds of the attempted microanastomoses were patent. The pretest predicted decent scores from poor performances with a sensitivity of 61.5%, specificity of 100%, positive predictive value of 100% and negative predictive value of 40%. Students and residents obtained significantly higher scores than surgeons. Since our course model is short, cost-effective and highly reproducible, it could be introduced and implemented anywhere as an educational prospect for preselecting young residents showing talent and natural predisposition and having ambitions towards microvascular reconstructive surgery.
Studio pilota sulle microanastomosi vascolari: risultati a confronto e prospettive didattiche future.
UNASSIGNED: L’introduzione dei lembi liberi microvascolari ha rivoluzionato la moderna chirurgia ricostruttiva. Purtroppo, l’accesso a corsi specifici e intensivi è attualmente limitato e costoso. Abbiamo organizzato uno studio pilota sulle microanastomosi vascolari con lo scopo di verificare: se un corso economico e facilmente riproducibile potesse trasmettere ai partecipanti delle abilità microchirurgiche di base; se il test preliminare scelto fosse predittivo dei risultati finali; e se l’età potesse essere un fattore in grado di influenzare la performance. Sono stati selezionati un numero complessivo di 30 partecipanti (10 studenti, 10 specializzandi e 10 chirurghi), senza nessuna precedente esperienza microchirurgica, ai quali è stato proposto un corso della durata di 3-5 ore. Le anastomosi conclusive, sottoposte a valutazione, sono state le prime realizzate da ciascun partecipante. Più della metà degli individui testati è stata in grado di confezionare entrambe le microanasromosi funzionanti e in un tempo inferiore alle 2 ore; nel complesso due terzi delle microanastomisi realizzate erano pervie. Il test preliminare è stato in grado di predire risultati finali buoni rispetto a risultati finali scarsi con una sensibilità del 61%, una specificità del 100%, un valore predittivo positivo pari al 100% ed un valore predittivo negativo del 40%. Studenti e specializzandi hanno ottenuto punteggi significativamente migliori rispetto ai chirurghi. Dato che il corso da noi proposto è breve, dai costi contenuti e facilmente riproducibile, riteniamo possa essere facilmente implementato in altre strutture al fine di selezionare giovani specializzandi dotati di talento con una naturale predisposizione per la microchirurgia, e che dimostrino interesse ed ambizione nel campo della chirurgia ricostruttiva.

BACKGROUND: Successful outcome of any vascularised free flap basically depends upon the successful restoration of circulation in the flap after anastomosis. As the flap ischemic time is the significant factor which determines the outcome of any free flaps, due consideration is given to reduce the time for anastomosis for reperfusion. The present study compares and evaluates whether the usage of microvascular couplers with the conventional suturing reduce the ischemic time of the free flaps.
METHODS: Thirty patients were randomly divided into two groups (each group consisting of 15 patients) for mandibular reconstruction using free fibular microvascular flap. In group 1, microanastomosis was done with conventional suturing whereas microvascular couplers were used in group 2. Intraoperatively, patency, leakage and tissue perfusion were assessed. The time taken for anastomosis (time taken for suturing and applying couplers) and flap ischemic time (from the time of flap division from the donor site till the flap is reperfused after anastomosis) were calculated for both the groups.
RESULTS: Significant decrease in time for anastomosis was observed in group 2, which resulted in decrease in flap ischemic time and in overall operating time.