Rat Microvascular Model is Tolerant to Technical Errors.

BACKGROUND: Extensive studies have been conducted using the rat model to understand the potential technical errors that lead to anastomotic failure. However, current literature indicates that the rat model has excellent tolerance to diverse errors committed by microsurgeons. The error-investigating rat model is often created by one or two experienced surgeons, and only one isolated technical error is examined. These biases may potentially cause limitations of the results from previous studies. Meanwhile, venous anastomoses have rarely been investigated in previous literature. Therefore, it is important to elucidate this topic with a more comprehensive study design. METHODS: Ninety-four arterial and 94 venous anastomoses on Sprague-Dawley rat femoral vessels that were performed by 47 microsurgeons who participated in the microsurgery course at the Columbia University and the University of Thessaloniki were evaluated. In total, 10 technical errors were examined: (1) disruption of suture line, (2) back-wall stitch, (3) oblique stitch, (4) wide bite, (5) partial thickness bite, (6) unequal suture distance, (7) tear in vessel wall, (8) excessively tight suture, (9) suture threads in lumen, and (10) large edge overlap. The frequency of each error committed, and the 30-minute postoperative patency was also recorded. The underlying causal relationship between these errors, potential interaction, and the short-term anastomosis patency was analyzed statistically. RESULTS: Only the back-wall stitch was found to have a significant causal effect on arterial anastomosis failure (p < 0.001). Back-wall stitch, wide bite, and partial thickness bite significantly impact venous anastomosis patency (p < 0.001). No other statistically significant result was found. CONCLUSION: Overall, the rat model is highly resilient to various technical errors despite these mistakes being often considered clinically unacceptable. Therefore, researchers need to consider the resilience of the rat model when designing and analyzing future studies. In addition, microsurgery instructors should focus on individual stitch quality rather than the final patency.

Resorbable Nerve Wraps: Can They Be Overtightened?

BACKGROUND: Nerve wrapping has been advocated to minimize scarring and adhesion following neurorrhaphy or neurolysis. A wrap should provide an enclosure that is snug enough to protect and support the affected nerve without strangulating the nerve. The degree to which resorbable wraps should be ": tightened" around the nerve is largely subjective with scant literature on the subject. The purpose of this study was to evaluate the effects of tightly fitting resorbable nerve wraps around intact rat sciatic nerves. METHODS: Twenty-four Sprague-Dawley rats underwent exposure and circumferential measurement of the right sciatic nerve. Porcine-derived extracellular matrix (ECM) wraps were trimmed and sutured to enclose the nerve with a tight (same as that of the nerve, n = 8) or loose (2.5x that of the nerve, n = 8) circumference. Sham-surgery control animals (n = 8) had no wrap treatment. Functional outcome was recorded biweekly by sciatic functional index (SFI) with walking track analysis and electrical stimulation. Animals were sacrificed at 12 weeks for histologic analyses. RESULTS: No withdrawal response could be evoked in the tight-wrap group until week 9, while significant improvement in SFI first occurred between weeks 5 and 7. By week 12, the tight-wrap group required 60% more current compared with baseline stimulation to produce a withdrawal response. They recovered 81% of SFI baseline values but also demonstrated significantly greater intraneural collagen content (p < 0.001) and lower axon density (p < 0.05) than in the loose-wrap and sham groups. The loose-wrap group had comparable functional and histologic outcomes to the sham control group. CONCLUSION: Resorbable ECM nerve wraps applied tightly around intact rat sciatic nerves caused significant functional impairment and histological changes characteristic of acute nerve compression. Significant but incomplete functional recovery was achieved by the tight-wrap group after 12 weeks, but such recovery may not apply in humans.

Smoothing the steep microsurgery learning curve: considering alternative suture sizes for early-stage microsurgery training with in vivo rat models.

BACKGROUND: Laboratory microsurgery training using invivo rat models is essential for clinical operation. However, challenges existin a structured training course when students transition from a non-livingmodel exercise to a living one. In the present article, we first demonstratethis steep learning curve in early-stage microsurgery training. We then proposethe potential solution of using various sizes of sutures for different trainingpurposes. METHODS: Twoseparate preliminary studies were included. First, we reviewed the records of25 students enrolled in our basic microsurgery training course. Each studentcompleted exercises in a non-living model before graduating to a live animalmodel where their performance on end-to-end arterial and venous anastomoses wasevaluated. Second, we examined the feasibility of different suture sizes in amillimeter microvascular anastomosis. Four groups of identical procedures inrat femoral artery were completed using sutures from 8-0 to 11-0. Patency rateand mean blood flow at 60 min post-op were measured and compared. RESULTS: Thirty-minute patency rates for firstarterial and venous anastomoses were 18/25 and 14/25. Those students who hadnon-patent anastomoses spent significantly longer time than those who hadpatent ones (p<.05). For varioussuture sizes, all groups achieved a 100% patency rate. No significantdifferences were found between the mean blood flow volume at 60 min post-op (p>.05). CONCLUSIONS: Steep learning curve existed in the early-stagemicrosurgery training when transitioning from non-living to living exercisemodels. The feasibility of using various suture sizes in millimeter anastomosismay be a potential solution for instructors to ease this steep learning curve.Level of Evidence: Not gradable.

Superiority of living animal models in microsurgical training: beyond technical expertise.

BACKGROUND: Many studies are investigating the role of living and nonliving models to train microsurgeons. There is controversy around which modalities account for the best microsurgical training. In this study, we aim to provide a systematic literature review of the practical modalities in microsurgery training and compare the living and nonliving models, emphasizing the superiority of the former. We introduce the concept of non-technical skill acquisition in microsurgical training with the use of living laboratory animals in the context of a novel proposed curriculum. METHODS: A literature search was conducted on PubMed/Medline and Scopus within the past 11 years based on a combination of the following keywords: "microsurgery," "training," "skills," and "models." The online screening process was performed by two independent reviewers with the Covidence tool. A total of 101 papers was identified as relevant to our study. The protocol was reported in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. RESULTS: Living models offer the chance to develop both technical and non-technical competencies (i.e., leadership, situation awareness, decision-making, communication, and teamwork). Prior experience with ex vivo tissues helps residents consolidate basic skills prior to performing more advanced techniques in the living tissues. Trainees reported a higher satisfaction rate with the living models. CONCLUSIONS: The combination of living and nonliving training microsurgical models leads to superior results; however, the gold standard remains the living model. The validity of the hypothesis that living models enhance non-technical skills remains to be confirmed.Level of evidence: Not ratable.

The Benefits of Expert Instruction in Microsurgery Courses.

BACKGROUND: Microsurgery requires repeated practice and training to achieve proficiency, and there are a variety of curriculums available. This study aims to determine the importance of an expert instructor to guide students through procedures. We compared student proficiency across two microsurgery courses: one with (Columbia University, United States [CU] cohort) and one without a dedicated microsurgery instructor (University of Thessaloniki, Greece [UT] cohort). METHODS: Students were divided into two cohorts of 22 students (UT cohort) and 25 students (CU cohort). Student progress was evaluated by examining patency (lift-up and milking tests), anastomotic timing, and quality (Anastomosis Lapse Index [ALI]) of end-to-end arterial and venous anastomoses on day 1 and again on day 5. Chi-squared tests evaluated patency immediately and 30 minutes postoperation. t-Tests evaluated anastomotic timing and ALI scores. p-Values < 0.05 were considered significant. RESULTS: We evaluated progress within and between each cohort. Within the CU cohort, the quality of the arterial and venous anastomosis improved, respectively (by 54%, p = 0.0059 and by 43%, p = 0.0027), the patency of both the arterial and venous anastomosis improved, respectively (by 44%, p = 0.0002 and by 40%, p = 0.0019), and timing of arterial and venous anastomosis reduced respectively (by 36%, p = 0.0002 and by 33%, p = 0.0010). The UT cohort improved the quality of their arterial anastomoses (by 29%, p = 0.0312). The UT cohort did not demonstrate significant improvement in the other above-mentioned parameters. The CU cohort improved materially over the UT cohort across categories of quality, patency, and timing. CONCLUSION: There are clear benefits of an expert instructor when examining the rate of progress and proficiency level attained at the conclusion of the course. We suggest students who are seeking to maximize proficiency in microsurgical procedures enroll in courses with an expert instructor.

Torsion is Tolerated in Arterial End to Venous Side Anastomoses in the Rat Model.

BACKGROUND: End-to-side (ETS) anastomoses are necessary for many procedures in microvascular surgery, such as free flap transfers. In training courses that use the rat model, the arterial end to venous side (AEVS) anastomosis is a common training exercise for ETS anastomoses. Surgeons-in-training often inadvertently twist the artery when completing the AEVS anastomosis; however, in the clinical setting, torsion is a reported risk factor for ETS anastomosis failure. The purpose of this study was to determine if torsion in an AEVS anastomosis would have a negative effect on patency in the rat model, accurately simulating the clinical scenario. METHODS: All AEVS anastomoses were completed in 15 Sprague-Dawley rats divided into three torsion cohorts: 0, 90, and 180 degrees. Torsion was created in the AEVS anastomosis by mismatching the first two sutures placed between the free femoral artery end and the venotomy. Patency was verified at 0, 2, and 4 hours postoperation via the oxygenated-deoxygenated test and transit-time ultrasound blood flow measurements. RESULTS: All AEVS anastomoses were patent 0, 2, and 4 hours postoperation according to both the oxygenated-deoxygenated test and transit-time ultrasound blood flow measurements. For the average blood flow measurements at 4 hours postoperation, the proximal measurements for 0, 90, and 180 degrees were -34.3, -18.7, and -13.8 mL/min respectively, and the distal measurements were 4.48, 3.46, and 2.90 mL/min, respectively. CONCLUSION: Torsion of 180 degrees does not affect early AEVS anastomosis patency in the rat model. This contrasts with the clinical setting, where torsion is reported to cause ETS anastomosis failure. Since AEVS anastomosis torsion is often difficult to appreciate visually, we suggested that microvascular surgery training instructors include a method to both detect and prevent AEVS anastomosis torsion, such as by marking the free femoral artery end with a marking pen or suture before beginning the anastomosis.

Large and Uneven Bites in End-to-End Anastomosis of the Rat Femoral Artery.

BACKGROUND: Successful microvascular anastomosis depends on sutures that adequately oppose both cut vessel edges. Trainees tend to take oversized or uneven bite. To improve early microsurgical skill acquisition using the rat, this study tests the belief that such bites compromise early patency by applying exaggerated bites to end-to-end arterial anastomoses. METHODS: Twelve Sprague-Dawley rats were randomly assigned to one of the four bite techniques to be applied to both femoral arteries (mean diameter, 0.8 mm). Large (L) and standard (S) bites measured 1.0 and 0.2 mm from the edge, respectively. Eight simple interrupted anastomoses were performed per bite technique, each labeled according to every proximal end bite size, followed by every distal end bite size: LL, LS, SL, and SS. Anastomosis time and blood flow rates were recorded and analyzed statistically. After sacrifice 5 days postoperation, anastomosis sections of each technique were examined histologically. RESULTS: All 24 anastomoses (100%) maintained patency for 5 days. There was no statistical difference between all postoperative blood flow measurements at any given time. Anastomosis times using LL, LS, SL, and SS bite techniques were 41.6, 33.2, 34.8, and 25.5 minutes, respectively. Anastomosis time for the traditional bite technique (SS) was significantly shorter than all other bite techniques (p < 0.05). Histological examination of the harvested segments from each group revealed similar pathophysiological features. CONCLUSION: Oversized bites (1 mm), placed symmetrically and asymmetrically across the anastomosis, do not affect early patency in the rat femoral artery. A reduced reliance on conventional guidelines for suture bites appears acceptable during microarterial anastomoses if the goal is vessel patency. However, we believe clinical competence involves the ability to place small, even bites consistently and uniformly. During microsurgical training, the occasional large bite need not be replaced; however, the trainee should be encouraged to take standard bites.

Creation of a Rat Lower Limb Lymphedema Model.

BACKGROUND: Lymphedema is a frequent complication after surgical treatments of cancer involving lymph node resection. However, research of lymphedema treatments, such as vascularized lymph node transfer, is limited by the absence of an adequate lymphedema animal model. The purpose of this study was to determine if we could create sustainable lower limb lymphedema in the rat with a combination of inguinal lymphadenectomy, circumferential skin and subcutaneous tissue excision, and radiotherapy. METHODS: Inguinal lymphadenectomies were completed in 15 Sprague-Dawley rats. In cohort A, 5 rats received a 0.5- to 1.0-cm wide excision of proximal thigh skin and subcutaneous tissue. This step was omitted for the 10 rats in cohort B. Cohort A then received a single radiation dose of 22.7 Gy, whereas cohort B received a cumulative dose of 40.5 Gy. Bioimpedance measurements were obtained monthly to assess lymphedema progression, and lymphatic drainage at 6 months postradiation was visualized via indocyanine green (ICG) lymphangiography. RESULTS: Two rats in cohort A developed visually appreciable lymphedema in the lower limb, with bioimpedance ratios of 0.684 and 0.542 and ankle circumference ratios of 1.294 and 1.061, respectively, consistent with lymphedema. Furthermore, ICG lymphangiography in these cohort A rats revealed impaired lower limb lymphatic drainage. In cohort B, however, bioimpedance and circumference ratios, and ICG lymphangiography, did not reveal abnormal lymphatic drainage. CONCLUSIONS: The combination of inguinal lymphadenectomy, circumferential skin and subcutaneous tissue excision, and radiotherapy can successfully create lower limb lymphedema in the rat. When soft tissue excision is omitted, lymphedema does not develop.

International microsurgery simulation society (IMSS) consensus statement on the minimum standards for a basic microsurgery course, requirements for a microsurgical anastomosis global rating scale and minimum thresholds for training.

INTRODUCTION: Microsurgery is a surgical technique that uses optical magnification as well as specific instruments to address necessary reconstructive procedures in different medical specialties. The apprenticeship of this technique requires overcoming a steep learning curve. There is a need for standardization of the training criteria in microsurgery. The International Microsurgery Simulation Society (IMSS) was born in 2011, since then its main objective has been to connect the main international specialists and educators of this sub-specialty to share and discuss the ethical and scientific basis of preclinical microsurgery teaching. METHODS: In order to achieve a consensus on the minimum standards for the organization of basic microsurgery training courses, the requirements for a microsurgical anastomosis global rating scale and minimum thresholds for training, a total of nineteen independent global experts participated in a formal consultative consensus development program. The agreement criteria for each statement was established when consensus of 65-100% was reached. RESULTS: There have been established six recommendations concerning minimum standards for a basic microsurgery course, one recommendation in relation to minimum thresholds for training and four recommendations regarding the global rating scale as gold standard for a microsurgical anastomosis assessment. The eleven defined recommendations reached the agreement threshold of 65-100%. CONCLUSIONS: The development of this consensus sets the minimum recommended requirements for conducting basic microsurgery training courses, as well as suggestions for objective assessment of the learning curve and skills of trainees.

Torsion Does Not Affect Early Vein Graft Patency in the Rat Femoral Artery Model.

BACKGROUND: Torsion of vein grafts is a commonly cited reason for graft failure in clinical setting. Many microsurgery training courses have incorporated vein graft procedures in their curricula, and vein graft torsion is a common technical error made by the surgeons in these courses. To improve our understanding of the clinical reproducibility of practicing vein graft procedures in microsurgery training courses, this study aims to determine if torsion can lead to early vein graft failure in nonsurvival surgery rat models. METHODS: Sprague-Dawley rats were divided into five cohorts with five rats per cohort for a total of 25 rats. Cohorts were labeled based on degree of vein graft torsion (0, 45, 90, 135, and 180 degrees). Torsion was created in the vein grafts at the distal arterial end by mismatching sutures placed between the proximal end of the vein graft and the distal arterial end. Vein graft patency was then verified 2 and 24 hours postoperation. RESULTS: All vein grafts were patent 2 and 24 hours postoperation. At 2 hours, the average blood flow rate measurements for 0, 45, 90, 135, and 180 degrees of torsion were 0.37 ± 0.02, 0.38 ± 0.04, 0.34 ± 0.01, 0.33 ± 0.01, and 0.29 ± 0.02 mL/min, respectively. At 24 hours, they were 0.94 ± 0.07, 1.03 ± 0.15, 1.26 ± 0.22, 1.41 ± 0.11, and 0.89 ± 0.15 mL/min, respectively. CONCLUSION: Torsion of up to 180 degrees does not affect early vein graft patency in rat models. To improve the clinical reproducibility of practicing vein graft procedures in rat models, we suggest that microsurgery instructors assess vein graft torsion prior to clamp release, as vessel torsion does not seem to affect graft patency once the clamps are removed.

Reestablishment of Lymphatic Drainage after Vascularized Lymph Node Transfer in a Rat Model.

BACKGROUND: Vascularized lymph node transfer has recently received attention as a potential surgical treatment for lymphedema. Despite good results in some series, the mechanism and benefits of vascularized lymph node transfer have yet to be fully understood. This study aimed to investigate the reestablishment of drainage into transferred lymph nodes following vascularized lymph node transfer in a rat model. METHODS: Seven rats underwent vascularized lymph node transfer. The operation performed on each rat consisted of two parts. First, the left groin lymph node basin with superficial epigastric vessels was harvested as a free flap. Second, the flap was reattached in the left groin of the rat by means of end-to-end microvascular anastomoses. Anastomosis patency was assessed immediately postoperatively and at the time of animal sacrifice. The rats were evaluated for reestablishment of lymphatic flow into the transplanted nodes at 1-month intervals for at least 6 months postoperatively. This was accomplished noninvasively by injecting the rats in their flanks with fluorescent indocyanine green, which was detected using a Photodynamic Eye infrared camera. RESULTS: Anastomoses were patent in all seven rats immediately postoperatively. No indocyanine green uptake was seen in the transplanted lymph node basins in the first 2 months postoperatively in any of the rats. In five of seven rats, however, indocyanine green uptake was demonstrated in the transplanted lymph node basin by 6 months (average, 13 weeks). CONCLUSION: The authors report uptake of indocyanine green in five of seven rats at an average of 13 weeks after lymph node transplantation, consistent with the reestablishment of lymphatic drainage into the transplanted nodes.

Histological Changes in the Rat Femoral Artery Following the Use of the Empty-and-Refill Test.

BACKGROUND: This study examines the effects of the empty-and-refill patency test on rat femoral arteries in the longer postoperative time period. METHODS: A simple arterial anastomosis was performed bilaterally on 20 rats. The empty-and-refill test was performed unilaterally in all rats, leaving the contralateral artery as an internal control. Rats were divided into two cohorts of 10 rats and survived for 48 hours and 2 weeks. Vessel patency was assessed prior to closing and immediately prior to sacrifice. The femoral arteries were harvested bilaterally and hematoxylin and eosin stains were performed. The femoral artery distal to the anastomosis in the region of the empty-and-refill test was histologically evaluated. RESULTS: All vessels were patent at the time of sacrifice. There was no statistical difference in the numeric scoring between the experimental and control vessels in the 48-hour cohort. Almost all vessels harvested at 48 hours showed endothelial cell loss distal to the anastomosis regardless of whether they underwent the empty-and-refill test. The only statistically significant difference in the 2-week cohort was an increase in adventitial smooth muscle proliferation in the experimental group. There were no other statistically significant results between the experimental and control groups at 2 weeks. An overall comparison of both cohorts revealed a statistically significant increase in endothelial cell number and intimal proliferation by 2 weeks postsurgery. CONCLUSION: The empty-and-refill test does not compromise rat femoral artery anastomotic patency, nor does it produce histological damage either 48 hours or 2 weeks postsurgery.

Defining Standards in Experimental Microsurgical Training: Recommendations of the European Society for Surgical Research (ESSR) and the International Society for Experimental Microsurgery (ISEM).

BACKGROUND: Expectations towards surgeons in modern surgical practice are extremely high with minimal complication rates and maximal patient safety as paramount objectives. Both of these aims are highly dependent on individual technical skills that require sustained, focused, and efficient training outside the clinical environment. At the same time, there is an increasing moral and ethical pressure to reduce the use of animals in research and training, which has fundamentally changed the practice of microsurgical training and research. Various animal models were introduced and widely used during the mid-20th century, the pioneering era of experimental microsurgery. Since then, high numbers of ex vivo training concepts and quality control measures have been proposed, all aiming to reduce the number of animals without compromising quality and outcome of training. SUMMARY: Numerous microsurgical training courses are available worldwide, but there is no general agreement concerning the standardization of microsurgical training. The major aim of this literature review and recommendation is to give an overview of various aspects of microsurgical training. We introduce here the findings of a previous survey-based analysis of microsurgical courses within our network. Basic principles behind microsurgical training (3Rs, good laboratory practice, 3Cs), considerations around various microsurgical training models, as well as several skill assessment tools are discussed. Recommendations are formulated following intense discussions within the European Society for Surgical Research (ESSR) and the International Society for Experimental Microsurgery (ISEM), based on scientific literature as well as on several decades of experience in the field of experimental (micro)surgery and preclinical research, represented by the contributing authors. Key Messages: Although ex vivo models are crucial for the replacement and reduction of live animal use, living animals are still indispensable at every level of training which aims at more than just a basic introduction to microsurgical techniques. Modern, competency-based microsurgical training is multi-level, implementing different objective assessment tools as outcome measures. A clear consensus on fundamental principles of microsurgical training and more active international collaboration for the sake of standardization are urgently needed.

Predicting Thrombosis Formation in 1-mm-Diameter Arterial Anastomoses with Transit-Time Ultrasound Technology.

BACKGROUND: Thrombosis is a common source of failure in anastomoses, flaps, and vascular grafts. Ensuring vessel patency is critical to the success of microvascular procedures. Any tool that can accurately predict the patency of an anastomosis intraoperatively would enable the surgeon to detect and correct flow restrictions while the patient is still in the operating room. METHODS: The authors used transit-time ultrasound technology in this pilot study to investigate whether a minimal cutoff value for quantitative postoperative blood flow (in milliliters per minute) could be established that would reliably predict sustained vessel patency at 24 hours postoperatively. Surgical end-to-end anastomoses were performed on 56 Sprague-Dawley rat femoral arteries with diameters ranging from 0.6 to 1.2 mm. Postoperative blood volume flow measurements were taken at 20-minute intervals up to 1 hour, and then again at 24 hours, to assess patency. RESULTS: Forty-seven anastomoses (83.9 percent ) were patent 24 hours after surgery. Nine anastomoses (16.1 percent ) thrombosed within 24 hours. Based on a receiver operating characteristic curve analysis, the optimal cutoff value for immediate postoperative flow for predicting thrombosis within 24 hours of microvascular anastomosis is 0.21 ml/minute. CONCLUSIONS: At 20 minutes postoperatively, blood flows greater than 0.30 ml/minute are highly suggestive of patency, and flows less than 0.21 ml/minute are highly suggestive of failure. The authors therefore recommend a minimal cutoff flow value of 0.30 ml/minute for vessels ranging from 0.6 to 1.2 mm in diameter to predict long-term postoperative vascular patency.

A Comparison of the Minimal-Touch Technique and the Eversion Technique for Microvascular Anastomosis in a Rat Model.

Background During microvascular anastomosis, needle placement is facilitated by inserting the tips of the forceps into the lumen of the vessel, rather than grasping and everting the luminal wall, to minimize trauma to the vessel. This study examines whether the vessel wall can be grasped and everted during microvascular anastomosis without compromising surgical outcomes. Methods A total of 20 Sprague-Dawley rats weighing between 252 and 483 g were used. Bilateral anastomoses of the animals' femoral arteries (mean size: 0.90 mm) were performed using two different techniques: the classic minimal-touch approach and the eversion technique. The first 10 animals were survived for 48 hours and the second 10 animals were survived for 2 weeks. Patency was assessed immediately after surgery and just before sacrifice. Hematoxylin and eosin stains were performed and each anastomosis scored according to a grading rubric assessing endothelial cell loss, neointimal proliferation, medial necrosis, adventitial inflammation, and inflammation thickness. Results The patency rates of both techniques were identical (100%). There was no difference in the patency rates of anastomoses evaluated 48 hours after surgery (100%) and 2 weeks after surgery (100%). Histological outcomes between the minimal-touch technique and the eversion method were similar. The thickness of adventitial inflammation at 2 weeks was the only outcome found to be statistically different (p = 0.046) between the two treatments and this difference favored the eversion technique (i.e., less inflammation thickness). Conclusion The eversion method of performing microvascular anastomosis provides comparable results to the classic minimal-touch approach in rat femoral artery anastomoses.

Effect of Microvascular Anastomosis Technique on End Product Outcome in Simulated Training: A Prospective Blinded Randomized Controlled Trial.

Background The aim of this article is to evaluate the difference in skills acquisition of two end-to-end microvascular anastomosis techniques-the triangulation and biangulation-in early microsurgery training. Method In this study, 32 candidates ranging from medical students to higher surgical trainees underwent a 5-day basic microsurgery course. On days 3 and 5 of the course, candidates performed two end-to-end anastomoses on cryopreserved rat aortas. One anastomosis was performed using the biangulation technique and the other using the triangulation technique. Candidates were randomized to the order of technique performed. Structural patency, errors performed, and suture distribution were evaluated randomly by a blinded reviewer using the anastomosis lapse index score and ImageJ (U.S. National Institutes of Health, Bethesda, MD) Software. Results A total of 128 anastomoses were evaluated during the study period. A total of six anastomoses performed with the biangulation technique, and four anastomoses with the triangulation technique, were physically occluded on day 3 of the course. On day 5, two biangulation technique anastomoses and one triangulation technique produced a nonpatent outcome. There was a statistically significant difference of patency rate between the 2 days of evaluation confirming evidence of skill acquisition but no statistically significant difference between the two techniques in relation to anastomotic patency, errors performed, or suture placement quality. Conclusion The biangulation and triangulation techniques of microvascular anastomosis produce similar outcomes in relation to vessel structural patency and quality of anastomosis when taught in early stages of microsurgery training. Our results suggest that both techniques are equally suitable in training novices, basic microsurgical skills.

Caffeine Does Not Reduce Blood Flow Following Arterial Anastomosis in the Rat.

Background Patients are usually advised not to consume caffeine following digital replantation. This study examined the effect of caffeine on blood flow distal to the site of anastomosis in the femoral arteries of rats. Methods A total of 28 Sprague-Dawley rats were used for this study. The femoral arteries were exposed bilaterally and baseline blood volume flow measurements were taken on intact arteries using a transit time flow-meter probe. All rats underwent transection and microvascular anastomosis of the femoral artery on the right side while the left side remained intact to serve as a control. The rats were then divided into two groups. In group 1, caffeine was administered (intraperitoneal injection of 40 mg caffeine/kg of body weight dissolved in saline) and in group 2 no caffeine was given. In both the groups, bilateral flow measurements were then taken at 30 and 60 minutes, respectively, following completion of the anastomosis. Results All anastomoses remained patent during the study time period. Caffeine had no statistical effect on blood flow distal to the anastomosis. Both anastomosed and control arteries demonstrated a statistically significant increase in blood flow at 30 and 60 minutes, respectively, postanastomosis that was independent of caffeine administration. Conclusions Caffeine does not have a statistically significant effect on blood flow distal to the anastomosis following microsurgical repair of the rat femoral artery.