Resident-performed free flap reconstruction: a retrospective comparison of microvascular coupler devices versus hand-sewn anastomosis

Resident-performed free flap reconstruction: a retrospective comparison of microvascular coupler devices versus hand-sewn anastomosis | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Resident-performed free flap reconstruction: a retrospective comparison of microvascular coupler devices versus hand-sewn anastomosis Yu-Hsiang Huang, Hung-Hui Liu, Po-Huang Chen, Chun-Yu Chen, Kuo-Feng Hsu, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7202826/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 22 Oct, 2025 Read the published version in European Journal of Plastic Surgery → Version 1 posted 8 You are reading this latest preprint version Abstract Background Microvascular anastomotic coupling devices (MACDs) help to improve the patency and reproducibility of venous anastomosis. However, owing to the high cost of MACDs in Taiwan, surgeons seldom use them. We compared the efficacy, surgical outcomes, and benefits of using MACDs versus traditional hand-sewn sutures for anastomosis. Methods This retrospective clinical study was conducted in the Plastic Surgery Division at the Tri-Service General hospital between December 2020 and October 2022. We compared the clinical characteristics and outcomes of two groups of patients who underwent free tissue transfer and venous anastomosis using traditional hand-sewn sutures or MACDs. The Synovis venous coupler (Synovis Micro Companies Alliance Inc, Birmingham, AL) was used in all coupled venous anastomoses. Results Overall, 81 patients were included in the study. Of these, traditional hand-sewn sutures were utilized in 46 patients and MACDs were used in 35 patients (43 venous anastomoses in total, all of which were end-to-end anastomoses). The success rates for the hand-sewn and MACD groups were 97.8% and 97.1%, respectively. The mean time taken for venous and arterial anastomosis in the MACD group was 93.26 min, compared with 102.48 min in the hand-sewn group ( p = 0.12). Additionally, the lengths of stay in the intensive care unit were 12.91 days for the hand-sewn group and 7.29 days for the MACD group ( p = 0.11). No thrombosis or leakage incidents occurred when using MACDs. Conclusions In resident-performed microvascular reconstruction, MACDs offer comparable success rates to hand-sewn techniques, with potential benefits in operative efficiency and postoperative recovery. These findings support the use of MACDs as a safe and effective tool in microsurgical training and practice.ot only in surgical outcomes but also in efficiency. Collectively, our results underscore the benefits of MACD use. Level of Evidence: Level III Free tissue transfer Microsurgery Microvascular anastomotic coupling devices (MACDs) Microsurgical training Economics Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Free tissue transfer has become a standard treatment for the reconstruction of complex defects with bone or tendon exposure, as it restores both form and function. Additionally, it is the gold standard for managing complicated soft or hard tissue defects in head and neck reconstruction [ 1 ]. Currently, microvascular anastomosis remains the most challenging and important technique affecting the success of free tissue transfers. The flap survival rate in free tissue transfer of head and neck reconstruction is approximately 95% [ 2 ]. Venous anastomosis is typically performed using traditional hand-sewn venous techniques. Nevertheless, venous anastomosis is considered more technically challenging than arterial anastomosis, and venous thrombosis remains one of the most frequent causes of total flap loss [ 3 , 4 ]. Furthermore, hand-sewn anastomosis not only prolongs the operative time but also requires technical skills. Thus, the microvascular anastomosis of veins is important for the survival rate of transferred tissues. The introduction of microvascular anastomotic coupling devices (MACDs) by Nakayama et al. in 1962 [ 5 ] has provided an alternative method for venous anastomosis. These MACDs have demonstrated effectiveness in enhancing the patency of venous anastomosis and the reproducibility of results. However, due to high MACD costs in Taiwan, surgeons rarely use venous MACDs in patients. This study aimed to compare the efficacy, intensive care unit (ICU) length of stay, and surgical outcomes of venous anastomosis using MACDs versus traditional hand-sewn anastomosis for microvascular reconstruction. Materials and Methods We retrospectively reviewed 81 consecutive cases of microvascular free tissue transfer in the Plastic Surgery Division at Tri-Service General hospital between December 2020 and October 2022. Surgeries were performed by senior fellows under the supervision of senior surgeons. Data on demographics of the patients, defect location, flap type, total anastomosis time (one artery, one or two veins), total operative time, ICU length of stay (days), MACD size, microvascular complications, and flap survival rate were collected and analyzed. The patients were categorized into the traditional hand-sewn and MACD groups. In the MACD group, patients underwent venous anastomosis with MACDs (Synovis Micro Companies Alliance Inc, Birmingham, AL), which consist of high-density polyethylene and surgical stainless-steel pins. The MACD diameters range from 1.0 to 4.0 mm, increasing by 0.5 mm intervals; we applied MACDs within the range of 1 to 4 mm (Fig. 1 ). In the hand-sewn group, the venous and arterial anastomoses were both performed using conventional hand-sewn sutures (9 − 0 or 10 − 0 Nylon; Ethicon). Moreover, arterial anastomosis preceded venous anastomosis. We also assessed the postoperative vascular patency, thrombosis, and flap survival by monitoring the clinical manifestations of the flaps, such as decreased Doppler signals, flap temperatures, and variations in the flap color or consistency. The primary outcomes focused on the flap failure rate, total anastomosis time, and ICU length of stay. The anastomotic time was defined as the duration from the vessel cutdown during harvesting to the completion of the anastomosis. This study was approved by the Institutional Review Board of the Tri-Service General Hospital, Taipei, Taiwan (TSGHIRB no. A202205127). Statistical analysis Descriptive data for continuous and categorical covariates are presented as means ± standard deviations and number of observations with percentages (%), respectively. To compare characteristics and covariates, Student’s t -tests and chi-squared tests were used for continuous and categorical variables, respectively. The odds ratio (OR) with a 95% confidence interval (CI) was estimated by comparing the traditional hand-sewn and MACD groups using multivariate logistic and linear regression analyses. Covariates included sex, age, flap, recipient site, malignancy, diabetes mellitus, peripheral arterial disease, hypertension, and albumin level. Two-sided p -values < 0.05 were considered indicative of statistical significance. Statistical analyses were performed using SPSS version 22.0 for Windows (IBM Inc., Chicago, IL, USA). Results In total, 81 patients were included in the study. Of these, traditional hand-sewn sutures were employed in 46 patients and MACDs were used in 35 patients (Table 1 ). The mean ages were 52.26 ± 12.71 and 56.03 ± 13.24 years for the hand-sewn and MACD groups, respectively. Males comprised 67.4% and 71.4% of the hand-sewn and MACD groups, respectively. In addition, we compared the patient characteristics of the hand-sewn vs. MACD groups, including albumin levels (3.36 ± 0.54 vs. 3.48 ± 0.54 mg/dL), hypertension (23.9% vs. 31.4%), diabetes mellitus (19.6% vs. 17.1%), peripheral artery disease (15.0% vs. 10.0%), and history of malignancy (69.6% vs. 85.7%), none of which were significantly different between the two groups (all p > 0.05). Table 1 Characteristics of the study patients Patient characteristics Hand-sewn ( n = 46) MACD ( n = 35) p -value Age (years) 52.26 ± 12.71 56.03 ± 13.24 0.19 Sex Male Female 31 (67.4%) 15 (32.6%) 25 (71.4%) 10 (28.6%) 0.69 Albumin (mg/dL) 3.36 ± 0.54 3.48 ± 0.54 0.34 HTN 11 (23.9%) 11 (31.4%) 0.45 DM 9 (19.6%) 6 (17.1%) 0.78 PAD Malignancy 3 (15.0%) 32 (69.6%) 3 (10.0%) 30 (85.7%) 0.67 0.09 Outcomes Operation time (min) Total anastomosis time (min) ICU length of stay (days) 719.41 ± 242.79 102.48 ± 32.38 12.91 ± 20.30 788.17 ± 181.55 93.26 ± 15.25 7.29 ± 3.43 0.17 0.12 0.11 Complication 8 (17.4%) 2 (5.7%) 0.17 Failure 1 (2.2%) 1 (2.9%) > 0.99 Testing by the Fisher’s exact, Wilcoxon, or Kruskal–Wallis tests MACD, microvascular anastomotic coupling device; HTN, hypertension; DM, diabetes mellitus; PAD, peripheral artery disease; ICU, intensive care unit The time required for vessel isolation and preparation was included in the total anastomosis time. As shown in Table 1 , the mean time taken for venous and arterial anastomosis was 93.26 ± 15.25 min in the MACD group and 102.48 ± 32.38 min in the hand-sewn group. However, this difference was not statistically significant ( p = 0.12). The lengths of stay in the ICU in the hand-sewn and MACD groups were 12.91 and 7.29 days, respectively ( p = 0.11). Anterolateral thigh flaps were the most commonly used flaps in both groups (Table 2 ). The reconstruction regions are shown in Fig. 2 , and the head and neck region was the most common in both groups. Table 2 Flaps in the study population Harvested flaps for reconstruction Hand-sewn ( n = 46) MACD ( n = 35) p -value ALT flap DIEP flap Fibula flap Radial forearm flap SCIP flap MSAP flap 33 (71.7%) 5 (10.9%) 0 (0.0%) 3 (6.5%) 2 (4.3%) 3 (6.5%) 30 (85.7%) 0 (0.0%) 2 (5.7%) 3 (8.6%) 0 (0.0%) 0 (0.0%) 0.04 Testing using the Fisher’s exact, Wilcoxon, or Kruskal–Wallis tests MACD, microvascular anastomotic coupling device; ALT, anterolateral thigh; DIEP, deep inferior epigastric artery perforator; SCIP, superficial circumflex iliac artery perforator; MSAP, medial sural artery perforator Additionally, no patients experienced thrombosis or intraoperative leakage events following anastomosis. The MACDs were used for venous anastomosis in 35 patients (43 venous anastomoses, Table 3 ), all of which were end-to-end anastomoses (Figs. 3 , 4 ). The diameters of the MACDs applied were 4, 3, 2, 1.5, and 1 mm in 1 (2.3%), 5 (11.6%), 14 (32.5%), 13 (30.2%), and 4 (9.3%) venous anastomoses, respectively. Table 3 MACD sizes used ( n = 43) MACD size (mm) Cases (n) Total (%) 1.0 4 9 1.5 13 30 2.0 14 33 2.5 6 14 3.0 5 12 4.0 1 2 MACD, microvascular anastomotic coupling device The time required for vessel isolation and preparation was included in the anastomosis time. The average time taken for venous and arterial anastomosis was 93.26 min in the MACD group and 102.48 min in the hand-sewn group. However, this difference was not statistically significant ( p = .12). The lengths of stay in the ICU in the hand-sewn and MACD groups were 12.91 and 7.29 days, respectively ( p = .11). To examine the outcomes between the hand-sewn and MACD groups, we performed unadjusted and adjusted logistic regression analyses (Table 4 ). These analyses revealed no statistically significant differences in the total anastomosis time, although the adjusted OR was − 11.79 (95% CI = -25.16 to 1.57, p = 0.09). Regarding the ICU length of stay, a statistically significant difference was observed between the two groups (adjusted OR = -4.91, 95% CI = -8.21 to -1.61, p = 0.01). Table 4 Outcomes of multivariate and univariate logistic regression analyses Outcome Univariate analysis Multivariate analysis Crude-OR (95% CI) p-value Adj-OR (95% CI) a p-value Complications 0.29 (0.06–1.45) 0.131 0.18 (0.02–1.32) 0.091 Failure 1.32 (0.08–21.92) 0.845 0.33 (0.00–78.87) 0.693 Length of ICU Stay -5.63 (-12.43–1.18) 0.109 -4.91 (-8.21– -1.61) 0.005 Total anastomosis time -9.22 (-20.83–2.39) 0.123 -11.79 (-25.16–1.57) 0.089 Operation time 68.76 (-27.32–164.84) 0.165 14.57 (-74.64–103.79) 0.750 a Results were adjusted by sex, age, flap, recipient site, malignancy, diabetes mellitus (DM), peripheral artery disease (PAD), hypertension (HTN), and albumin level. CI, confidence interval; OR, odds ratio. The success rates for the hand-sewn and MACD groups were 97.8% and 97.1%, respectively ( p = 1.000). Further, seven patients in the hand-sewn group required flap salvage. One of the flaps showed arterial insufficiency, and the remaining demonstrated venous thrombosis. One of the flaps ultimately failed. In the MACD group, one flap required re-exploration due to venous thrombosis and eventually failed. All reported complications occurred in cases of end-to-end anastomosis. The complication rates between the two groups were not significantly different. Discussion Microvascular anastomosis is an essential and critical component of free flap reconstruction. Flap failure rates range from approximately 2–5% based on the location and type of reconstruction [ 4 ]. A meticulous hand-sewn suture technique is crucial for preventing endothelial intimal injury that may lead to potential thrombosis. The applications of MACDs are well established, with both clinical and animal experiments demonstrating advantages over the traditional hand-sewn technique in free tissue transfer [ 6 , 7 ]. Additionally, MACDs are considered superior to traditional hand-sewn sutures for several reasons. First, the venous congestion rate is lower with MACDs than with traditional hand-sewn sutures [ 8 , 9 ]. This is because MACDs present intima-to-intima anastomosis and ensure reliable vessel eversion, leaving no foreign objects that could potentially cause thrombosis [ 7 ]. Moreover, inadequate hand-sewn sutures can cause endothelial intimal lacerations, distortion of the vessels, and unequal interculture distances, which may contribute to thrombus formation and eventual flap failure [ 10 ]. Concerning mismatched vessels, the MACD can accommodate a discrepancy in the vessel diameter of up to 3:1 [ 11 ]. A randomized controlled trial conducted by Senthil Murugan et al. [ 12 ] revealed that the use of MACDs shortens the time required to complete the anastomosis while yielding similar clinical outcomes compared to traditional techniques. Although several advantages of the use of MACDs have been proposed, few studies have unequivocally demonstrated the benefits of MACDs over hand-sewn sutures. In our study, the success rates for the hand-sewn and MACD groups were 97.8% and 97.1%, respectively, with a slightly but not significantly higher flap success rate in the hand-sewn group. Herein, we applied MACDs ranging from 1.0 to 4.0 mm in size. Some clinical studies have shown that smaller MACD sizes may lead to a higher thrombosis rate. Hanson et al. [ 13 ] revealed a significantly higher venous thrombosis rate with the 1.5 mm diameter MACD than with larger-diameter MACDs or traditional hand-sewn sutures (6.9 %, p = 0.04). In addition, a retrospective single-center cohort study that aimed to analyze the influence of MACD size on the timing and revision rate of 437 patients who underwent free flap reconstructions of the head and neck region demonstrated a > 40% reduction in the revision rate for each additional millimeter in MACD size [ 14 ]. In the present study, the most common site for reconstruction was the head and neck region, followed by the lower extremities. We used 1.5 mm MACDs in 13 venous anastomoses (30.2%) and 1 mm MACDs in 4 venous anastomoses (9.3%), with no observable venous congestion. However, further studies with larger sample sizes and comparative analyses are crucial. Undoubtedly, time consumption is an essential cost factor to consider within the healthcare system. We analyzed the total anastomosis time, and the results for the hand-sewn suture and MACD groups were 102.48 and 93.26 min, respectively. Thus, the anastomosis time was approximately 9 min longer in the hand-sewn group than in the MACD group. A previous clinical trial demonstrated that, on average, 15–40 min were required for a hand-sewn anastomosis compared with 5–15 min when using MACDs [ 15 ]. Although our results align with the findings of this previous study, they were not statistically significant. The acquisition of microsurgical skills is a necessity in plastic surgeon residency training programs. Microsurgery techniques require hand-eye coordination, fine movements, and meticulous suturing skills, and achieving proficiency in these skills requires substantial time and effort. In our microsurgical training programs, we use a live rat model to practice femoral anastomoses [ 16 ]. Cho et al. [ 17 ] demonstrated an overall free flap survival rate of 95.5% in resident-based operations; moreover, MACDs were utilized in these cases, and the results were comparable to the 97.8% success rate observed in our study for the MACD group. The outcomes in the current study are not inferior to those of previous studies [ 4 ]. With live animal training programs and the application of MACDs in venous anastomoses, younger surgeons or colleagues may be able to independently perform microsurgical reconstruction safely and with shortened learning curves. As previously mentioned, a series of studies have demonstrated the advantages of using MACDs on surgical outcomes, including better survival rates and time savings. Economic analyses of MACD usage have also been performed. Edmund et al. [ 18 ] showed that the use of MACDs resulted in an average savings of £154. Cope et al. [ 19 ] analyzed 153 anastomoses that were performed in 87 free flaps and found that MACD utilization reduced the operating time and provided possible cost savings in free-flap surgery. Another economic comparison between hand-sewn anastomoses and MACD usage by Head et al. [ 20 ] demonstrated that the total operating room expenses were reduced by $ 30.82 per minute, with an average operating time reduction of 16.9 min, when using an MACD, although disposable costs were increased by $ 284.40. In our study, the total anastomosis time was reduced by an average of 9.2 min. Generally, patients who undergo free tissue transfer are transferred to the ICU for postoperative monitoring, including assessments of the Doppler signal, flap temperature, and variations in flap color or consistency. Our results revealed that the ICU length of stay was 12.91 and 7.29 days in the hand-sewn and MACD groups, respectively. The ICU length of stay was reduced by approximately 5 days when using MACDs. This reduction was significantly different according to the adjusted logistic regression analyses. The difference could be attributed to the lower complication rate in the MACD group. Additionally, the total fixed ICU costs were approximately $ 300 per day within our hospital system. Overall, the reduced total anastomosis time, less frequent revisions, and shorter ICU stays may represent a financial benefit. Furthermore, the cost of MACD usage is covered by the National Healthcare Insurance in Taiwan (Republic of China) for free flap reconstruction in patients with head and neck malignancies. This study had certain limitations. This was a retrospective study, and further randomized clinical studies with larger sample sizes should be conducted. Moreover, the discrepancy between vessel diameters and MACDs should be analyzed in future studies. Conclusion As highlighted in our study and in alignment with previous research, the use of MACDs offers several advantages. These benefits include a reduction in total anastomosis time by approximately 9 min, and a slightly lower complication rate. No incidents of thrombosis or leakage were reported with MACD use, even when MACDs with smaller diameters were employed. Moreover, the MACD group had a shorter ICU length of stay for postoperative care. The results underscore the overall benefits of MACD use. Further, the adoption of MACDs allows residents and fellows to independently perform vessel anastomosis, with shorter learning curves. Thus, compared with traditional hand-sewn anastomosis for microvascular reconstruction, MACDs demonstrate reliability not only in surgical outcomes but also in economic efficiency. Declarations Competing interests: The authors have no relevant financial or non-financial interests to disclose. Ethics approval: This study was approved by the Institutional Review Board of our hospital. Consent to participate: This retrospective chart review was approved by the Institutional Review Board of the Tri-Service General Hospital, Taipei, Taiwan (TSGHIRB no. A202205127). The requirement for informed consent was waived because the study used de‑identified data and posed minimal risk to participants. Consent to publish: Informed consent was waived because the study used de‑identified data and posed minimal risk to participants. Funding: The authors declare that no funds, grants, or other support were received during the preparation of this manuscript. Author Contribution All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Yu-Hsiang Huang, Hung-Hui Liu and Po-Huang Chen. The first draft of the manuscript was written by Yu-Hsiang Huang and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript. Data availability statement: The datasets generated during and/or analyzed during the current study are available from the corresponding author upon reasonable request. References Frederick JW, Sweeny L, Carroll WR, Rosenthal EL (2013) Microvascular anastomotic coupler assessment in head and neck reconstruction. Otolaryngol Head Neck Surg 149(1):67–70. https://doi.org/10.1177/0194599813486875 Copelli C, Tewfik K, Cassano L, Pederneschi N, Catanzaro S, Manfuso A, Cocchi R (2017) Management of free flap failure in head and neck surgery. Acta Otorhinolaryngol Ital 37(5):387–392. https://doi.org/10.14639/0392-100X-1376 Ahn CY, Shaw WW, Berns S, Markowitz BL (1994) Clinical experience with the 3M microvascular coupling anastomotic device in 100 free-tissue transfers. Plast Reconstr Surg 93(7):1481–1484. https://doi.org/10.1097/00006534-199406000-00022 Kroll SS, Schusterman MA, Reece GP, Miller MJ, Evans GR, Robb GL, Baldwin BJ (1996) Choice of flap and incidence of free flap success. 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Cite Share Download PDF Status: Published Journal Publication published 22 Oct, 2025 Read the published version in European Journal of Plastic Surgery → Version 1 posted Editorial decision: Revision requested 12 Aug, 2025 Reviews received at journal 11 Aug, 2025 Reviewers agreed at journal 06 Aug, 2025 Reviewers agreed at journal 04 Aug, 2025 Reviewers invited by journal 04 Aug, 2025 Editor assigned by journal 29 Jul, 2025 Submission checks completed at journal 29 Jul, 2025 First submitted to journal 24 Jul, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7202826","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":495390089,"identity":"ab6a7966-00ef-4463-ba7a-3472e4d9ff68","order_by":0,"name":"Yu-Hsiang Huang","email":"","orcid":"","institution":"Division of Plastic and Reconstructive Surgery, Department of Surgery, Tri-Service General Hospital, National Defense Medical 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Chen","email":"","orcid":"","institution":"Division of Plastic Surgery, Department of Surgery, Armed Forces Taoyuan General Hospital","correspondingAuthor":false,"prefix":"","firstName":"Chun-Yu","middleName":"","lastName":"Chen","suffix":""},{"id":495390093,"identity":"12435cdc-6cbc-4d02-9d69-fdbf0f89deef","order_by":4,"name":"Kuo-Feng Hsu","email":"","orcid":"","institution":"Division of Plastic and Reconstructive Surgery, Department of Surgery, Tri-Service General Hospital, National Defense Medical University","correspondingAuthor":false,"prefix":"","firstName":"Kuo-Feng","middleName":"","lastName":"Hsu","suffix":""},{"id":495390096,"identity":"40614676-224e-42aa-a0a9-0b64630522f6","order_by":5,"name":"Kuang-Ling Ou","email":"","orcid":"","institution":"Division of Plastic and Reconstructive Surgery, Department of Surgery, Tri-Service General Hospital, National Defense Medical University","correspondingAuthor":false,"prefix":"","firstName":"Kuang-Ling","middleName":"","lastName":"Ou","suffix":""},{"id":495390097,"identity":"6f83f5cf-59df-418d-bb10-758ca14c95a0","order_by":6,"name":"Chih-Hsin Wang","email":"","orcid":"","institution":"Division of Plastic and Reconstructive Surgery, Department of Surgery, Tri-Service General Hospital, National Defense Medical University","correspondingAuthor":false,"prefix":"","firstName":"Chih-Hsin","middleName":"","lastName":"Wang","suffix":""},{"id":495390098,"identity":"dcebb14f-0b3d-40b1-a4d0-8621e40addaa","order_by":7,"name":"Yuan-Sheng Tzeng","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA80lEQVRIiWNgGAWjYDAC9uYDBh8OSAAZDQzMxGnhOZZQOAOkhecAkpYD+LRI+Bh85gCpkEggUovuDAbDzQxnLKL5Jd8Yfi6osGHgb+9OYP7YhluL2e2GZOOCGxK5M2fnGEvPOJPGIHHm7AaGg/i03DlwzHjGB4ncDbdzDKR52w4zGADZDAe34dFyI7H9Nw9Iy80zxr+J1JLMYMwDdNiGGzxmRNpy5hiD4YwzQL/0pJVZ85xJ4wH55cDZf3i0HO//YPDhWF1uP/vhzbd5Kmzk+Nt7Nz6oOINbCxLgMACRPCDiAFEagCnmAZEKR8EoGAWjYKQBAN7+XIz7bAv4AAAAAElFTkSuQmCC","orcid":"","institution":"Division of Plastic and Reconstructive Surgery, Department of Surgery, Tri-Service General Hospital, National Defense Medical University","correspondingAuthor":true,"prefix":"","firstName":"Yuan-Sheng","middleName":"","lastName":"Tzeng","suffix":""}],"badges":[],"createdAt":"2025-07-24 08:03:54","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7202826/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7202826/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00238-025-02351-0","type":"published","date":"2025-10-22T16:16:49+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":88498540,"identity":"c96a065d-2c66-4d82-8376-9923eb9409e1","added_by":"auto","created_at":"2025-08-07 06:35:26","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":86937,"visible":true,"origin":"","legend":"\u003cp\u003eSizes of microvascular anastomotic coupling devices (MACDs) used\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7202826/v1/291431c68a942784fe82ad81.png"},{"id":88499612,"identity":"27ea3b6b-8bcf-4c20-9330-3886e7876499","added_by":"auto","created_at":"2025-08-07 06:43:26","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":66766,"visible":true,"origin":"","legend":"\u003cp\u003eThe reconstructive regions in the hand-sewn and MACD groups. MACD, microvascular anastomotic coupling device\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7202826/v1/3c2d056c8c150a1603e63fe0.png"},{"id":88499613,"identity":"ac3d00cf-c6be-448e-a223-7d6cd0e3cf44","added_by":"auto","created_at":"2025-08-07 06:43:26","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":40500,"visible":true,"origin":"","legend":"\u003cp\u003eCompletion of end-to-end anastomosis in head and neck reconstruction\u003c/p\u003e","description":"","filename":"3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7202826/v1/a59455469e951aff7407bb6d.jpg"},{"id":88498551,"identity":"f8c67db5-92a7-454a-8873-2cb4b46445b1","added_by":"auto","created_at":"2025-08-07 06:35:26","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":1172664,"visible":true,"origin":"","legend":"\u003cp\u003eMACD use in lower extremity reconstruction. MACD, microvascular anastomotic coupling device\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-7202826/v1/890b2e15c0fb017a322d4b1b.png"},{"id":94490219,"identity":"09ec1b5b-f250-4a9a-8bac-4849c96bb71b","added_by":"auto","created_at":"2025-10-27 17:08:16","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1929287,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7202826/v1/331bc931-7736-452d-8d58-ae0a64ac17aa.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Resident-performed free flap reconstruction: a retrospective comparison of microvascular coupler devices versus hand-sewn anastomosis","fulltext":[{"header":"Introduction","content":"\u003cp\u003eFree tissue transfer has become a standard treatment for the reconstruction of complex defects with bone or tendon exposure, as it restores both form and function. Additionally, it is the gold standard for managing complicated soft or hard tissue defects in head and neck reconstruction [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Currently, microvascular anastomosis remains the most challenging and important technique affecting the success of free tissue transfers. The flap survival rate in free tissue transfer of head and neck reconstruction is approximately 95% [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Venous anastomosis is typically performed using traditional hand-sewn venous techniques. Nevertheless, venous anastomosis is considered more technically challenging than arterial anastomosis, and venous thrombosis remains one of the most frequent causes of total flap loss [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Furthermore, hand-sewn anastomosis not only prolongs the operative time but also requires technical skills. Thus, the microvascular anastomosis of veins is important for the survival rate of transferred tissues.\u003c/p\u003e\u003cp\u003eThe introduction of microvascular anastomotic coupling devices (MACDs) by Nakayama et al. in 1962 [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e] has provided an alternative method for venous anastomosis. These MACDs have demonstrated effectiveness in enhancing the patency of venous anastomosis and the reproducibility of results. However, due to high MACD costs in Taiwan, surgeons rarely use venous MACDs in patients. This study aimed to compare the efficacy, intensive care unit (ICU) length of stay, and surgical outcomes of venous anastomosis using MACDs versus traditional hand-sewn anastomosis for microvascular reconstruction.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003eWe retrospectively reviewed 81 consecutive cases of microvascular free tissue transfer in the Plastic Surgery Division at Tri-Service General hospital between December 2020 and October 2022. Surgeries were performed by senior fellows under the supervision of senior surgeons. Data on demographics of the patients, defect location, flap type, total anastomosis time (one artery, one or two veins), total operative time, ICU length of stay (days), MACD size, microvascular complications, and flap survival rate were collected and analyzed. The patients were categorized into the traditional hand-sewn and MACD groups. In the MACD group, patients underwent venous anastomosis with MACDs (Synovis Micro Companies Alliance Inc, Birmingham, AL), which consist of high-density polyethylene and surgical stainless-steel pins. The MACD diameters range from 1.0 to 4.0 mm, increasing by 0.5 mm intervals; we applied MACDs within the range of 1 to 4 mm (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). In the hand-sewn group, the venous and arterial anastomoses were both performed using conventional hand-sewn sutures (9\u0026thinsp;\u0026minus;\u0026thinsp;0 or 10\u0026thinsp;\u0026minus;\u0026thinsp;0 Nylon; Ethicon). Moreover, arterial anastomosis preceded venous anastomosis. We also assessed the postoperative vascular patency, thrombosis, and flap survival by monitoring the clinical manifestations of the flaps, such as decreased Doppler signals, flap temperatures, and variations in the flap color or consistency. The primary outcomes focused on the flap failure rate, total anastomosis time, and ICU length of stay. The anastomotic time was defined as the duration from the vessel cutdown during harvesting to the completion of the anastomosis. This study was approved by the Institutional Review Board of the Tri-Service General Hospital, Taipei, Taiwan (TSGHIRB no. A202205127).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eStatistical analysis\u003c/h2\u003e\u003cp\u003eDescriptive data for continuous and categorical covariates are presented as means\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviations and number of observations with percentages (%), respectively. To compare characteristics and covariates, Student\u0026rsquo;s \u003cem\u003et\u003c/em\u003e-tests and chi-squared tests were used for continuous and categorical variables, respectively. The odds ratio (OR) with a 95% confidence interval (CI) was estimated by comparing the traditional hand-sewn and MACD groups using multivariate logistic and linear regression analyses. Covariates included sex, age, flap, recipient site, malignancy, diabetes mellitus, peripheral arterial disease, hypertension, and albumin level. Two-sided \u003cem\u003ep\u003c/em\u003e-values\u0026thinsp;\u0026lt;\u0026thinsp;0.05 were considered indicative of statistical significance. Statistical analyses were performed using SPSS version 22.0 for Windows (IBM Inc., Chicago, IL, USA).\u003c/p\u003e\u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eIn total, 81 patients were included in the study. Of these, traditional hand-sewn sutures were employed in 46 patients and MACDs were used in 35 patients (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The mean ages were 52.26\u0026thinsp;\u0026plusmn;\u0026thinsp;12.71 and 56.03\u0026thinsp;\u0026plusmn;\u0026thinsp;13.24 years for the hand-sewn and MACD groups, respectively. Males comprised 67.4% and 71.4% of the hand-sewn and MACD groups, respectively. In addition, we compared the patient characteristics of the hand-sewn vs. MACD groups, including albumin levels (3.36\u0026thinsp;\u0026plusmn;\u0026thinsp;0.54 vs. 3.48\u0026thinsp;\u0026plusmn;\u0026thinsp;0.54 mg/dL), hypertension (23.9% vs. 31.4%), diabetes mellitus (19.6% vs. 17.1%), peripheral artery disease (15.0% vs. 10.0%), and history of malignancy (69.6% vs. 85.7%), none of which were significantly different between the two groups (all \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eCharacteristics of the study patients\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePatient characteristics\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eHand-sewn\u003c/p\u003e\u003cp\u003e(\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;46)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eMACD\u003c/p\u003e\u003cp\u003e(\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;35)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003ep\u003c/em\u003e-value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAge (years)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e52.26\u0026thinsp;\u0026plusmn;\u0026thinsp;12.71\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e56.03\u0026thinsp;\u0026plusmn;\u0026thinsp;13.24\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.19\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSex\u003c/p\u003e\u003cp\u003eMale\u003c/p\u003e\u003cp\u003eFemale\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e31 (67.4%)\u003c/p\u003e\u003cp\u003e15 (32.6%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e25 (71.4%)\u003c/p\u003e\u003cp\u003e10 (28.6%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.69\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAlbumin (mg/dL)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3.36\u0026thinsp;\u0026plusmn;\u0026thinsp;0.54\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3.48\u0026thinsp;\u0026plusmn;\u0026thinsp;0.54\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.34\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHTN\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e11 (23.9%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e11 (31.4%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.45\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDM\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e9 (19.6%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6 (17.1%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.78\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePAD\u003c/p\u003e\u003cp\u003eMalignancy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3 (15.0%)\u003c/p\u003e\u003cp\u003e32 (69.6%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3 (10.0%)\u003c/p\u003e\u003cp\u003e30 (85.7%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.67\u003c/p\u003e\u003cp\u003e0.09\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eOutcomes\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eOperation time (min)\u003c/p\u003e\u003cp\u003eTotal anastomosis time (min)\u003c/p\u003e\u003cp\u003eICU length of stay (days)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e719.41\u0026thinsp;\u0026plusmn;\u0026thinsp;242.79\u003c/p\u003e\u003cp\u003e102.48\u0026thinsp;\u0026plusmn;\u0026thinsp;32.38\u003c/p\u003e\u003cp\u003e12.91\u0026thinsp;\u0026plusmn;\u0026thinsp;20.30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e788.17\u0026thinsp;\u0026plusmn;\u0026thinsp;181.55\u003c/p\u003e\u003cp\u003e93.26\u0026thinsp;\u0026plusmn;\u0026thinsp;15.25\u003c/p\u003e\u003cp\u003e7.29\u0026thinsp;\u0026plusmn;\u0026thinsp;3.43\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.17\u003c/p\u003e\u003cp\u003e0.12\u003c/p\u003e\u003cp\u003e0.11\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eComplication\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e8 (17.4%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2 (5.7%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.17\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFailure\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1 (2.2%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1 (2.9%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e\u0026gt;\u0026thinsp;0.99\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"4\"\u003eTesting by the Fisher\u0026rsquo;s exact, Wilcoxon, or Kruskal\u0026ndash;Wallis tests\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd colspan=\"4\"\u003eMACD, microvascular anastomotic coupling device; HTN, hypertension; DM, diabetes mellitus; PAD, peripheral artery disease; ICU, intensive care unit\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eThe time required for vessel isolation and preparation was included in the total anastomosis time. As shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, the mean time taken for venous and arterial anastomosis was 93.26\u0026thinsp;\u0026plusmn;\u0026thinsp;15.25 min in the MACD group and 102.48\u0026thinsp;\u0026plusmn;\u0026thinsp;32.38 min in the hand-sewn group. However, this difference was not statistically significant (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.12). The lengths of stay in the ICU in the hand-sewn and MACD groups were 12.91 and 7.29 days, respectively (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.11).\u003c/p\u003e\u003cp\u003eAnterolateral thigh flaps were the most commonly used flaps in both groups (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The reconstruction regions are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, and the head and neck region was the most common in both groups.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eFlaps in the study population\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHarvested flaps for reconstruction\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eHand-sewn\u003c/p\u003e\u003cp\u003e(\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;46)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eMACD\u003c/p\u003e\u003cp\u003e(\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;35)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003ep\u003c/em\u003e-value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eALT flap\u003c/p\u003e\u003cp\u003eDIEP flap\u003c/p\u003e\u003cp\u003eFibula flap\u003c/p\u003e\u003cp\u003eRadial forearm flap\u003c/p\u003e\u003cp\u003eSCIP flap\u003c/p\u003e\u003cp\u003eMSAP flap\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e33 (71.7%)\u003c/p\u003e\u003cp\u003e5 (10.9%)\u003c/p\u003e\u003cp\u003e0 (0.0%)\u003c/p\u003e\u003cp\u003e3 (6.5%)\u003c/p\u003e\u003cp\u003e2 (4.3%)\u003c/p\u003e\u003cp\u003e3 (6.5%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e30 (85.7%)\u003c/p\u003e\u003cp\u003e0 (0.0%)\u003c/p\u003e\u003cp\u003e2 (5.7%)\u003c/p\u003e\u003cp\u003e3 (8.6%)\u003c/p\u003e\u003cp\u003e0 (0.0%)\u003c/p\u003e\u003cp\u003e0 (0.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.04\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"4\"\u003eTesting using the Fisher\u0026rsquo;s exact, Wilcoxon, or Kruskal\u0026ndash;Wallis tests\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd colspan=\"4\"\u003eMACD, microvascular anastomotic coupling device; ALT, anterolateral thigh; DIEP, deep inferior epigastric artery perforator; SCIP, superficial circumflex iliac artery perforator; MSAP, medial sural artery perforator\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eAdditionally, no patients experienced thrombosis or intraoperative leakage events following anastomosis. The MACDs were used for venous anastomosis in 35 patients (43 venous anastomoses, Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e), all of which were end-to-end anastomoses (Figs.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). The diameters of the MACDs applied were 4, 3, 2, 1.5, and 1 mm in 1 (2.3%), 5 (11.6%), 14 (32.5%), 13 (30.2%), and 4 (9.3%) venous anastomoses, respectively.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eMACD sizes used (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;43)\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"3\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMACD size (mm)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCases (n)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eTotal (%)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e9\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e13\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e14\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e33\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e14\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e12\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e4.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"3\"\u003eMACD, microvascular anastomotic coupling device\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe time required for vessel isolation and preparation was included in the anastomosis time. The average time taken for venous and arterial anastomosis was 93.26 min in the MACD group and 102.48 min in the hand-sewn group. However, this difference was not statistically significant (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.12). The lengths of stay in the ICU in the hand-sewn and MACD groups were 12.91 and 7.29 days, respectively (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.11). To examine the outcomes between the hand-sewn and MACD groups, we performed unadjusted and adjusted logistic regression analyses (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). These analyses revealed no statistically significant differences in the total anastomosis time, although the adjusted OR was \u0026minus;\u0026thinsp;11.79 (95% CI = -25.16 to 1.57, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.09). Regarding the ICU length of stay, a statistically significant difference was observed between the two groups (adjusted OR = -4.91, 95% CI = -8.21 to -1.61, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.01).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eOutcomes of multivariate and univariate logistic regression analyses\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eOutcome\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eUnivariate analysis\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e\u003cp\u003eMultivariate analysis\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCrude-OR (95% CI)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003ep-value\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAdj-OR (95% CI)\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003ep-value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eComplications\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.29 (0.06\u0026ndash;1.45)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0.131\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.18 (0.02\u0026ndash;1.32)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.091\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFailure\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e1.32 (0.08\u0026ndash;21.92)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0.845\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.33 (0.00\u0026ndash;78.87)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.693\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eLength of ICU Stay\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e-5.63 (-12.43\u0026ndash;1.18)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0.109\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-4.91 (-8.21\u0026ndash; -1.61)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.005\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTotal anastomosis time\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e-9.22 (-20.83\u0026ndash;2.39)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0.123\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-11.79 (-25.16\u0026ndash;1.57)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.089\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eOperation time\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e68.76 (-27.32\u0026ndash;164.84)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0.165\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e14.57 (-74.64\u0026ndash;103.79)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.750\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"5\"\u003e\u003csup\u003ea\u003c/sup\u003e Results were adjusted by sex, age, flap, recipient site, malignancy, diabetes mellitus (DM), peripheral artery disease (PAD), hypertension (HTN), and albumin level. CI, confidence interval; OR, odds ratio.\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eThe success rates for the hand-sewn and MACD groups were 97.8% and 97.1%, respectively (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;1.000). Further, seven patients in the hand-sewn group required flap salvage. One of the flaps showed arterial insufficiency, and the remaining demonstrated venous thrombosis. One of the flaps ultimately failed. In the MACD group, one flap required re-exploration due to venous thrombosis and eventually failed. All reported complications occurred in cases of end-to-end anastomosis. The complication rates between the two groups were not significantly different.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eMicrovascular anastomosis is an essential and critical component of free flap reconstruction. Flap failure rates range from approximately 2\u0026ndash;5% based on the location and type of reconstruction [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. A meticulous hand-sewn suture technique is crucial for preventing endothelial intimal injury that may lead to potential thrombosis. The applications of MACDs are well established, with both clinical and animal experiments demonstrating advantages over the traditional hand-sewn technique in free tissue transfer [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Additionally, MACDs are considered superior to traditional hand-sewn sutures for several reasons. First, the venous congestion rate is lower with MACDs than with traditional hand-sewn sutures [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. This is because MACDs present intima-to-intima anastomosis and ensure reliable vessel eversion, leaving no foreign objects that could potentially cause thrombosis [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Moreover, inadequate hand-sewn sutures can cause endothelial intimal lacerations, distortion of the vessels, and unequal interculture distances, which may contribute to thrombus formation and eventual flap failure [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Concerning mismatched vessels, the MACD can accommodate a discrepancy in the vessel diameter of up to 3:1 [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. A randomized controlled trial conducted by Senthil Murugan et al. [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e] revealed that the use of MACDs shortens the time required to complete the anastomosis while yielding similar clinical outcomes compared to traditional techniques.\u003c/p\u003e\u003cp\u003eAlthough several advantages of the use of MACDs have been proposed, few studies have unequivocally demonstrated the benefits of MACDs over hand-sewn sutures. In our study, the success rates for the hand-sewn and MACD groups were 97.8% and 97.1%, respectively, with a slightly but not significantly higher flap success rate in the hand-sewn group.\u003c/p\u003e\u003cp\u003eHerein, we applied MACDs ranging from 1.0 to 4.0 mm in size. Some clinical studies have shown that smaller MACD sizes may lead to a higher thrombosis rate. Hanson et al. [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e] revealed a significantly higher venous thrombosis rate with the 1.5 mm diameter MACD than with larger-diameter MACDs or traditional hand-sewn sutures (6.9\u003cem\u003e%, p\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.04). In addition, a retrospective single-center cohort study that aimed to analyze the influence of MACD size on the timing and revision rate of 437 patients who underwent free flap reconstructions of the head and neck region demonstrated a\u0026thinsp;\u0026gt;\u0026thinsp;40% reduction in the revision rate for each additional millimeter in MACD size [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. In the present study, the most common site for reconstruction was the head and neck region, followed by the lower extremities. We used 1.5 mm MACDs in 13 venous anastomoses (30.2%) and 1 mm MACDs in 4 venous anastomoses (9.3%), with no observable venous congestion. However, further studies with larger sample sizes and comparative analyses are crucial.\u003c/p\u003e\u003cp\u003eUndoubtedly, time consumption is an essential cost factor to consider within the healthcare system. We analyzed the total anastomosis time, and the results for the hand-sewn suture and MACD groups were 102.48 and 93.26 min, respectively. Thus, the anastomosis time was approximately 9 min longer in the hand-sewn group than in the MACD group. A previous clinical trial demonstrated that, on average, 15\u0026ndash;40 min were required for a hand-sewn anastomosis compared with 5\u0026ndash;15 min when using MACDs [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Although our results align with the findings of this previous study, they were not statistically significant.\u003c/p\u003e\u003cp\u003eThe acquisition of microsurgical skills is a necessity in plastic surgeon residency training programs. Microsurgery techniques require hand-eye coordination, fine movements, and meticulous suturing skills, and achieving proficiency in these skills requires substantial time and effort. In our microsurgical training programs, we use a live rat model to practice femoral anastomoses [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Cho et al. [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e] demonstrated an overall free flap survival rate of 95.5% in resident-based operations; moreover, MACDs were utilized in these cases, and the results were comparable to the 97.8% success rate observed in our study for the MACD group. The outcomes in the current study are not inferior to those of previous studies [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. With live animal training programs and the application of MACDs in venous anastomoses, younger surgeons or colleagues may be able to independently perform microsurgical reconstruction safely and with shortened learning curves.\u003c/p\u003e\u003cp\u003eAs previously mentioned, a series of studies have demonstrated the advantages of using MACDs on surgical outcomes, including better survival rates and time savings. Economic analyses of MACD usage have also been performed. Edmund et al. [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e] showed that the use of MACDs resulted in an average savings of \u0026pound;154. Cope et al. [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e] analyzed 153 anastomoses that were performed in 87 free flaps and found that MACD utilization reduced the operating time and provided possible cost savings in free-flap surgery. Another economic comparison between hand-sewn anastomoses and MACD usage by Head et al. [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e] demonstrated that the total operating room expenses were reduced by \u003cspan\u003e$\u003c/span\u003e30.82 per minute, with an average operating time reduction of 16.9 min, when using an MACD, although disposable costs were increased by \u003cspan\u003e$\u003c/span\u003e284.40. In our study, the total anastomosis time was reduced by an average of 9.2 min. Generally, patients who undergo free tissue transfer are transferred to the ICU for postoperative monitoring, including assessments of the Doppler signal, flap temperature, and variations in flap color or consistency. Our results revealed that the ICU length of stay was 12.91 and 7.29 days in the hand-sewn and MACD groups, respectively. The ICU length of stay was reduced by approximately 5 days when using MACDs. This reduction was significantly different according to the adjusted logistic regression analyses. The difference could be attributed to the lower complication rate in the MACD group. Additionally, the total fixed ICU costs were approximately \u003cspan\u003e$\u003c/span\u003e300 per day within our hospital system. Overall, the reduced total anastomosis time, less frequent revisions, and shorter ICU stays may represent a financial benefit. Furthermore, the cost of MACD usage is covered by the National Healthcare Insurance in Taiwan (Republic of China) for free flap reconstruction in patients with head and neck malignancies.\u003c/p\u003e\u003cp\u003eThis study had certain limitations. This was a retrospective study, and further randomized clinical studies with larger sample sizes should be conducted. Moreover, the discrepancy between vessel diameters and MACDs should be analyzed in future studies.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eAs highlighted in our study and in alignment with previous research, the use of MACDs offers several advantages. These benefits include a reduction in total anastomosis time by approximately 9 min, and a slightly lower complication rate. No incidents of thrombosis or leakage were reported with MACD use, even when MACDs with smaller diameters were employed. Moreover, the MACD group had a shorter ICU length of stay for postoperative care. The results underscore the overall benefits of MACD use. Further, the adoption of MACDs allows residents and fellows to independently perform vessel anastomosis, with shorter learning curves. Thus, compared with traditional hand-sewn anastomosis for microvascular reconstruction, MACDs demonstrate reliability not only in surgical outcomes but also in economic efficiency.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003ch2\u003eCompeting interests:\u003c/h2\u003e\u003cp\u003eThe authors have no relevant financial or non-financial interests to disclose.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eEthics approval:\u003c/strong\u003e\u003cp\u003e This study was approved by the Institutional Review Board of our hospital.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eConsent to participate:\u003c/strong\u003e\u003cp\u003e This retrospective chart review was approved by the Institutional Review Board of the Tri-Service General Hospital, Taipei, Taiwan (TSGHIRB no. A202205127). The requirement for informed consent was waived because the study used de‑identified data and posed minimal risk to participants.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eConsent to publish:\u003c/strong\u003e\u003cp\u003e Informed consent was waived because the study used de‑identified data and posed minimal risk to participants.\u003c/p\u003e\u003c/p\u003e\u003ch2\u003eFunding:\u003c/h2\u003e\u003cp\u003eThe authors declare that no funds, grants, or other support were received during the preparation of this manuscript.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eAll authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Yu-Hsiang Huang, Hung-Hui Liu and Po-Huang Chen. The first draft of the manuscript was written by Yu-Hsiang Huang and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e\u003ch2\u003eData availability statement:\u003c/h2\u003e\u003cp\u003eThe datasets generated during and/or analyzed during the current study are available from the corresponding author upon reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eFrederick JW, Sweeny L, Carroll WR, Rosenthal EL (2013) Microvascular anastomotic coupler assessment in head and neck reconstruction. 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Gland Surg 5(2):88\u0026ndash;92. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3978/j.issn.2227-684X.2015.05.14\u003c/span\u003e\u003cspan address=\"10.3978/j.issn.2227-684X.2015.05.14\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eCope C, Lee K, Stern H, Pennington D (2000) Use of the vascular closure staple clip applier for microvascular anastomosis in free-flap surgery. Plast Reconstr Surg 106(1):107\u0026ndash;110. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1097/00006534-200007000-00020\u003c/span\u003e\u003cspan address=\"10.1097/00006534-200007000-00020\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHead LK, McKay DR (2018) Economic comparison of hand-sutured and coupler-assisted microvascular anastomoses. J Reconstr Microsurg 34(1):71\u0026ndash;76. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1055/s-0037-1606540\u003c/span\u003e\u003cspan address=\"10.1055/s-0037-1606540\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"european-journal-of-plastic-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ejps","sideBox":"Learn more about [European Journal of Plastic Surgery](https://link.springer.com/journal/238)","snPcode":"238","submissionUrl":"https://submission.nature.com/new-submission/238/3","title":"European Journal of Plastic Surgery","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Free tissue transfer, Microsurgery, Microvascular anastomotic coupling devices (MACDs), Microsurgical training, Economics","lastPublishedDoi":"10.21203/rs.3.rs-7202826/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7202826/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMicrovascular anastomotic coupling devices (MACDs) help to improve the patency and reproducibility of venous anastomosis. However, owing to the high cost of MACDs in Taiwan, surgeons seldom use them. We compared the efficacy, surgical outcomes, and benefits of using MACDs versus traditional hand-sewn sutures for anastomosis.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis retrospective clinical study was conducted in the Plastic Surgery Division at the Tri-Service General hospital between December 2020 and October 2022. We compared the clinical characteristics and outcomes of two groups of patients who underwent free tissue transfer and venous anastomosis using traditional hand-sewn sutures or MACDs. The Synovis venous coupler (Synovis Micro Companies Alliance Inc, Birmingham, AL) was used in all coupled venous anastomoses.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eOverall, 81 patients were included in the study. Of these, traditional hand-sewn sutures were utilized in 46 patients and MACDs were used in 35 patients (43 venous anastomoses in total, all of which were end-to-end anastomoses). The success rates for the hand-sewn and MACD groups were 97.8% and 97.1%, respectively. The mean time taken for venous and arterial anastomosis in the MACD group was 93.26 min, compared with 102.48 min in the hand-sewn group (\u003cem\u003ep\u003c/em\u003e = 0.12). Additionally, the lengths of stay in the intensive care unit were 12.91 days for the hand-sewn group and 7.29 days for the MACD group (\u003cem\u003ep\u003c/em\u003e = 0.11). No thrombosis or leakage incidents occurred when using MACDs.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn resident-performed microvascular reconstruction, MACDs offer comparable success rates to hand-sewn techniques, with potential benefits in operative efficiency and postoperative recovery. These findings support the use of MACDs as a safe and effective tool in microsurgical training and practice.ot only in surgical outcomes but also in efficiency. Collectively, our results underscore the benefits of MACD use.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eLevel of Evidence: Level III\u003c/strong\u003e\u003c/p\u003e","manuscriptTitle":"Resident-performed free flap reconstruction: a retrospective comparison of microvascular coupler devices versus hand-sewn anastomosis","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-07 06:35:21","doi":"10.21203/rs.3.rs-7202826/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-08-12T07:20:31+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-11T10:43:24+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"178056356021057971804819170330014771926","date":"2025-08-06T10:41:01+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"210791939118775188695353505181933581689","date":"2025-08-04T12:19:37+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-08-04T09:39:18+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-07-29T08:09:23+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-07-29T08:07:50+00:00","index":"","fulltext":""},{"type":"submitted","content":"European Journal of Plastic Surgery","date":"2025-07-24T07:48:24+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"european-journal-of-plastic-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ejps","sideBox":"Learn more about [European Journal of Plastic Surgery](https://link.springer.com/journal/238)","snPcode":"238","submissionUrl":"https://submission.nature.com/new-submission/238/3","title":"European Journal of Plastic Surgery","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"46b4443f-5389-4168-a919-37251887e5cf","owner":[],"postedDate":"August 7th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-10-27T16:24:25+00:00","versionOfRecord":{"articleIdentity":"rs-7202826","link":"https://doi.org/10.1007/s00238-025-02351-0","journal":{"identity":"european-journal-of-plastic-surgery","isVorOnly":false,"title":"European Journal of Plastic Surgery"},"publishedOn":"2025-10-22 16:16:49","publishedOnDateReadable":"October 22nd, 2025"},"versionCreatedAt":"2025-08-07 06:35:21","video":"","vorDoi":"10.1007/s00238-025-02351-0","vorDoiUrl":"https://doi.org/10.1007/s00238-025-02351-0","workflowStages":[]},"version":"v1","identity":"rs-7202826","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7202826","identity":"rs-7202826","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}