Microvascular Anastomosis Research Articles

Evaluation of a novel anastomotic device in the animal model: A feasibility, safety, and efficacy study

A novel device was designed to assist with microvascular arterial anastomoses. This study compares the safety and efficacy of the anastomosis-assisting device with manual suturing in an ovine model. Arteries with a diameter ranging from 2 to 4mm were transected and anastomosed at four locations. A comparison was done between manual anastomoses and anastomoses performed with a novel anastomotic device in seven sheep. All the device-assisted anastomoses were performed by a single surgeon. At day 45±7, anastomotic sites were dissected to determine patency, and samples were obtained for pathology. Thirteen of 13 (100%) samples from the Vesseal™ group demonstrated patency both on the day the anastomoses were performed and after the 45-day follow-up period. All four additional anastomoses performed using the Vesseal™ were found patent. In the hand-suturing group, six of six (100%) samples demonstrated patency on the day of the anastomoses and five of six (83%) were patent after the follow-up period. No thromboses or adverse events were observed in the anastomoses in either group. No difference in histopathology of the anastomoses was observed between the groups. The anastomosis-assisting device is a safe and efficacious alternative to hand suturing. The patency rates of device-assisted anastomoses were greater than those of manual suturing and pose no additional risk, as demonstrated by clinical observation, histopathology, and macroscopic evaluation. The Vesseal™ anastomosis-assisting device may be a viable alternative to manual suturing, with an ergonomic and intuitive design, short learning curve, and consistent results.

Microsurgical training in vein anastomoses: the use of systemic heparin in a rat model.

To investigate whether the use of systemic heparin could be useful for vein microvascular anastomoses in microsurgical training on rats. Femoral end-to-end venous anastomoses were performed on both thighs of 40 wistar rats by two microsurgery trainees from October 2018 to February 2019 (80 anastomoses in total). We divided the rats into 2 groups of 20 specimens (40 femoral end-to-end anastomoses) each: group A received no heparin administration; group B received subcutaneous systemic heparin administration before starting dissection. We compared both vein patency after the procedures. Patency tests showed no difference between the two groups after 5 minutes. At the delayed test after 120 minutes, vein patency was significantly better in the systemic heparin group (85,0% vs 55,0%). Even though both trainees judged practicing on both groups very instructive, they found useful performing anastomoses when heparin was administrated. We suggest including the use of systemic heparin in microsurgery training programs, especially for the beginners. Systemic heparin administration in rat models is educative for trainees.

Variations in Payer-Negotiated Prices for Head and Neck Reconstructive Surgery.

Little is known about pricing for reconstructive procedures of the head and neck. As of January 2021, the Centers for Medicare and Medicaid Services requires hospitals to disclose payer-negotiated prices for services, offering new insight into prices for privately insured patients. Cross-sectional analysis. Turquoise database. Payer-negotiated facility fees for 41 reconstructive surgeries were grouped by procedure type: primary closure, skin grafts, tissue rearrangement, locoregional flaps, or free flaps. Prices were normalized to account for local labor costs, then calculated as percent markup in excess of Medicare reimbursement. The mean percent markup between procedure groups was compared by the Kruskal-Wallis test. Subset analyses were performed to compare mean percent markup using a Student's ttest. We also assessed price variation by calculating the ratio of 90th/10thpercentile mean prices both across and within hospitals. In total, 1324 hospitals (85% urban, 81% nonprofit, 49% teaching) were included. Median payer-negotiated fees showed an increasing trend with more complex procedures, ranging from $379.54 (interquartile range [IQR], $230.87-$656.96) for Current Procedural Terminology (CPT) code 12001 ("simple repair of superficial wounds ≤2.5 cm")to $5422.60 ($3983.55-$8169.41) for CPT code 20969 ("free osteocutaneous flap with microvascular anastomosis"). Median percent markup was highest for primary closure procedures (576.17% [IQR, 326.28%-1089.34%]) and lowest for free flaps (99.56% [37.86%-194.02%]). Higher mean percent markups were observed for rural, for-profit, non-Northeast, nonteaching, and smaller hospitals. Wide variation in private payer-negotiated facility fees exists for head/neck reconstruction surgeries. Further research is necessary to better understand how pricing variation may correlate with out-of-pocket costs and quality of care.

The impact of using the internal mammary artery as a recipient vessel on medial mastectomy skin flap perfusion in autologous breast reconstruction: An observational study using indocyanine green

The internal mammary artery (IMA) is the preferred recipient vessel for microvascular anastomosis in immediate autologous breast reconstruction following skin-sparing mastectomy (SSM). Although the IMA accounts for approximately 60% of the blood supply to the breast, the exact contribution to the mastectomy skin flap perfusion is unclear. The aim of this observational study was to investigate the impact of using the IMA as a recipient vessel on medial mastectomy skin flap perfusion assessed with indocyanine green angiography (ICGA). This observational study included ten consecutive women who underwent immediate autologous breast reconstructions following SSM. Two intraoperative indocyanine green (ICG) assessments were performed to assess tissue perfusion of the upper and lower part of the medial mastectomy skin flap: the first following the SSM and the second after clamping the IMA. During a 120-second angiography, three additional images were made after 60, 90, and 120s. The ICG inflow time and mean, minimum, and maximum fluorescence intensities (FIs) were obtained. Four unilateral and six bilateral autologous breast reconstructions were included. There was no difference in tissue perfusion when comparing the inflow time (24.1s vs. 23.0s, P=0.348), the mean FI (131.4 vs. 124.0, P=0.126), minimum FI (28.6 vs. 33.4, P=0.086), and maximum FI (253.1 vs. 247.6, P=0.166) before and after clamping the IMA. According to this study, the use of the IMA as a recipient vessel does not reduce medial mastectomy skin flap perfusion in patients undergoing immediate autologous breast reconstructions following SSM.

Quantification of motion during microvascular anastomosis simulation using machine learning hand detection.

Microanastomosis is one of the most technically demanding and important microsurgical skills for a neurosurgeon. A hand motion detector based on machine learning tracking technology was developed and implemented for performance assessment during microvascular anastomosis simulation. A microanastomosis motion detector was developed using a machine learning model capable of tracking 21 hand landmarks without physical sensors attached to a surgeon's hands. Anastomosis procedures were simulated using synthetic vessels, and hand motion was recorded with a microscope and external camera. Time series analysis was performed to quantify the economy, amplitude, and flow of motion using data science algorithms. Six operators with various levels of technical expertise (2 experts, 2 intermediates, and 2 novices) were compared. The detector recorded a mean (SD) of 27.6 (1.8) measurements per landmark per second with a 10% mean loss of tracking for both hands. During 600 seconds of simulation, the 4 nonexperts performed 26 bites in total, with a combined excess of motion of 14.3 (15.5) seconds per bite, whereas the 2 experts performed 33 bites (18 and 15 bites) with a mean (SD) combined excess of motion of 2.8 (2.3) seconds per bite for the dominant hand. In 180 seconds, the experts performed 13 bites, with mean (SD) latencies of 22.2 (4.4) and 23.4 (10.1) seconds, whereas the 2 intermediate operators performed a total of 9 bites with mean (SD) latencies of 31.5 (7.1) and 34.4 (22.1) seconds per bite. A hand motion detector based on machine learning technology allows the identification of gross and fine movements performed during microanastomosis. Economy, amplitude, and flow of motion were measured using time series data analysis. Technical expertise could be inferred from such quantitative performance analysis.

(199) Anterolateral Thigh Flap Phalloplasty for Micropenis

Abstract Introduction Congenital micropenis is defined as a normally formed penis with a stretched penile length less than 2.5 standard deviations below the mean for that man’s age and ethnicity. Micropenis may present as an isolated condition or with other genital or multi-system abnormalities. Penile reconstruction or phalloplasty may be required where topical and systemic hormonal treatment have failed. The most common flap used for phalloplasty is the radial artery forearm free flap phalloplasty. Other alternatives include the anterolateral thigh (ALT), musculocutaneous latissimus dorsi and abdominal flaps. Objective The aim of this video is to illustrate the technique for penile reconstruction using a pedicled ALT flap without integrated urethra. Methods A 21-year-old man with micropenis and hypospadias from a disorder of sexual differentiation (46XY) presents for penile reconstruction following multiple failed attempts at hypospadias repair. He requested an ALT flap without integrated urethra because he is dependent on a long-term suprapubic catheter due to a hypocontractile bladder. Intraoperative vascular doppler identified 3 perforators from the descending branch of the lateral circumflex iliac artery of the left leg. The flap was designed centred on the perforators with dimensions of 14cm (length), 13cm (width at base) and 12cm (width at tip). The flap was raised carefully and transferred to the recipient groin. The neophallus was constructed and microsurgical anastomosis of the lateral cutaneous of the thigh to one of the dorsal penile nerves with 8/0 nylon was completed. The partially divided left vastus lateralis muscle was re-approximated and the skin edges drawn in and flattened. The left thigh was then resurfaced with a 14/1000 of an inch split-thickness skin graft from the contralateral thigh. All wounds were dressed. Results The man had an uneventful post-operative course with careful vascular monitoring, and he was discharged on day 10. He is currently awaiting glans-sculpting and will eventually proceed with insertion of an inflatable erectile device. Conclusions Penile reconstruction using an ALT flap can be offered to a well-informed and motivated man with a micropenis following appropriate assessment. As shown, the technique requires careful dissection of the perforator vessels and can usually be transferred as a pedicled flap. Pedicled flaps do not require microvascular anastomosis and therefore have a lower risk of vascular compromise. Further esthetic and functional refinements like the insertion of an erectile device are possible in later stages, if desired. Disclosure No

Repair using the pectoralis major musculocutaneous flap for refractory anastomotic leakage after total esophagectomy

BackgroundThe pectoralis major musculocutaneous flap (PMMF) is a pedicled flap often used as a reconstruction option in head and neck surgery, especially in cases with poor wound healing. However, applying PMMF after esophageal surgery is uncommon. We report here, the case of a successfully repaired refractory anastomotic fistula (RF) after total esophagectomy, by PMMF.Case presentationA 73-year-old man had a history of hypopharyngolaryngectomy, cervical esophagectomy, and reconstruction using a free jejunal graft for hypopharyngeal carcinosarcoma at the age of 54. He also received conservative treatment for pharyngo-jejunal anastomotic leakage (AL), then postoperative radiation therapy. This time, he was diagnosed with carcinosarcoma in the upper thoracic esophagus; cT3rN0M0, cStageII, according to the Japanese Classification of Esophageal Cancer 12th Edition. As a salvage surgery, thoracoscopic total resection of the esophageal remnant and reconstruction using gastric tube via posterior mediastinal route was performed. The distal side of the jejunal graft was cut and re-anastomosed with the top of the gastric tube. An AL was observed on the 6th postoperative day (POD), and after 2 months of conservative treatment was then diagnosed as RF. The 3/4 circumference of the anterior wall of the gastric tube was ruptured for 6 cm in length, and surgical repair using PMMF was performed on POD71. The edge of the defect was exposed and the PMMF (10 × 5 cm) fed by thoracoacromial vessels was prepared. Then, the skin of the flap and the wedge of the leakage were hand sutured via double layers with the skin of the flap facing the intestinal lumen. Although a minor AL was observed on POD19, it healed with conservative treatment. No complications, such as stenosis, reflux, re-leakage, were observed over 3 years of postoperative follow-up.ConclusionsThe PMMF is a useful option for repairing intractable AL after esophagectomy, especially in cases with large defect, as well as difficulties for microvascular anastomosis due to previous operation, radiation, or wound inflammation.

Papaverine loaded injectable and thermosensitive hydrogel system for improving survival of rat dorsal skin flaps

Vasospasm during reconstructive microsurgery is a common, uncertain, and devastating phenomena concerning flap survival. Topical vasodilators as antispasmodic agents are widely used to reduce vasospasm and enhance microvascular anastomosis in reconstructive microsurgery. In this study, thermo-responsive hydrogel (CNH) was fabricated by grafting chitosan (CS) and hyaluronic acid (HA) to poly(N-isopropylacrylamide) (PNIPAM). Papaverine, an anti-spasmodic agent, was then loaded to evaluate its effect on rat skin flap survival. Post-operative flap survival area and water content of rat dorsal skin flap were measured at 7 days after intradermal application of control hydrogel (CNHP0.0) and papaverine loaded hydrogel (CNHP0.4). Tissue malondialdehyde (MDA) content and superoxide dismutase (SOD) activity was measured using enzyme linked immunosorbent assay (ELISA) to determine oxidative stress in flaps. Hematoxylin and eosin (H&E) staining and immunohistochemistry (IHC) were performed to evaluate flap angiogenesis and inflammatory markers. Results showed that CNHP0.4 hydrogel could reduce tissue edema (35.63 ± 4.01%), improve flap survival area (76.30 ± 5.39%), increase SOD activity and decrease MDA content. Consequently, it also increased mean vessel density, upregulated expression of CD34 and VEGF, decreased macrophage infiltration, and reduced CD68 and CCR7 expression based on IHC staining. Overall, these results indicate that CNHP0.4 hydrogel can enhance angiogenesis with anti-oxidative and anti-inflammatory effects and promote skin flap survival by preventing vascular spasm.Graphical

A comparison study of vessel twisting by different microsurgical suture techniques in a chicken wing artery side to side bypass training model.

Microvascular anastomosis, particularly side-to-side (STS) bypass, is a complex surgical procedure. While several suture techniques exist, none of them is superior to the others. We assessed the association between various STS bypass techniques and vessel twisting using chicken wing training models. Three suture techniques were compared over an anterior wall suture procedure. The unidirectional continuous suture (UCS) group used a downward "right-to-left" continuous suture. The reverse continuous suture (RCS) group used a downward "left-to-right" continuous suture. The interrupted suture (IS) group used the standard interrupted suture. The number of samples in each of the three groups was 30 (n=90). We compared the incidence of vessel twisting and rotation angles across groups. Vessel twisting occurred in 96.7%, 56.7%, and 0% of the cases in the UCS, IS, and RCS groups, respectively. The incidence of vessel twisting differed significantly in all 3 groups (p<0.001), with an apparent trend (p=0.002). The mean rotation angles were 201˚±90.6˚, 102˚±107.6˚, and 0˚ in the UCS, IS, and RCS groups, respectively, which were significantly different (p<0.001). On excluding cases without twisting, the rotation angles of twisted vessels in the UCS and IS groups were 207.9˚±83.7˚ and 180˚±77.9˚, respectively, which yielded a significant difference between these groups (p<0.001). We found that the incidence and trend of vessel twisting differed significantly across suture techniques. The RCS technique may aid in preventing vessel twisting in the STS bypass procedure.

The Impact of Venous Anastomosis Technique on Outcomes of Free Tissue Transfer to the Head and Neck.

Objectives: To evaluate the impact of different techniques of microvascular venous anastomosis on the outcome of free tissue transfer to the head and neck. Methods: Retrospective case series of patients undergoing microvascular free tissue transfer (MFTT) from January 2006 to September 2021. Chi-square tests and t-tests were utilized to identify differences in flap outcomes by technique, and log-binomial regression analyses were utilized to identify differences in flap outcomes by technique. Results: A total of 1055 consecutive MFTTs were analyzed. One hundred four cases required a return to the operating room for any reason, and 19 were attributed to venous compromise (18.0%). Ultimately, there were 22 FTT failures requiring complete revision (2.1%). In total, 1055 MFTTs involved 1352 venous anastomoses, ranging from 1 to 3 anastomoses in each case. End-to-end (ETE) was used 1040 times (76.9%) and end-to-side (ETS) 204 times (15.0%). The calculated risk ratio for venous complication for ETS compared with ETE was 1.17 (0.34-3.98). A microvascular coupler was used in 355 cases (33.6%). The calculated risk ratio for coupler compared with suture anastomoses was 0.92 (0.35-2.39). Conclusions: There were no significant difference in regard to outcomes of MFTT when comparing ETE with ETS, nor when comparing coupler with suture anastomoses.

The conjoined latissimus dorsi and parascapular free flap for reconstruction of extensive soft tissue defects

Durable and resilient soft tissue reconstruction of vast defects of the extremities or the torso. Reconstruction of disproportionately large defects, particularly in cases of simultaneous bone and joint reconstruction. History of surgery or irradiation of upper back and axilla, impossibility of surgery under lateral positioning; relative contraindications in wheelchair users, hemiplegics, or amputees. General anesthesia and lateral positioning. First, the parascapular flap is harvested, with the initial skin incision made medially in order to identify the medial triangular space and the circumflex scapular artery. Flap raising then proceeds from caudal to cranial. Second, the latissimus dorsi is harvested, with the lateral border being dissected free first, before the thoracodorsal vessels are visualized on its undersurface. Flap raising then proceeds from caudal to cranial. Third, the parascapular flap is advanced through the medial triangular space. If the circumflex scapular and thoracodorsal vessels originate separately from the subscapular axis, an in-flap anastomosis is warranted. Subsequent microvascular anastomoses should be performed outside the zone of injury, typically in an end-to-end fashion of the vein and end-to-side fashion of the artery. Postoperative anticoagulation with low-molecular-weight heparin under anti-Xa monitoring (semitherapeutic in normal-risk and therapeutic in high-risk cases). Hourly clinical assessment of flap perfusion for 5consecutive days, followed by stepwise relaxation of immobilization and commencement of dangling procedures in cases of lower extremity reconstruction. Between 2013 and 2018, 74conjoined latissimus dorsi and parascapular flaps were transplanted to cover vast defects of the lower (n = 66) and upper extremity (n = 8). The mean defect size was 723 ± 482 cm2 and the mean flap size was 635 ± 203 cm2. Eight flaps required in-flap anastomoses for separate vascular origins. There was no case of total flap loss.

Factors Associated with Free Flap Viability at Dr. Mohammad Hoesin General Hospital, Palembang, Indonesia

Introduction: A free flap is part of reconstructive surgery. This technique takes tissue or bone flaps along with their original vascular supply and performs microvascular anastomosis of the pedicle arteries and veins at the recipient site. Several risk factors that influence the occurrence of flap failure are still a major concern, such as age, gender, defect size, duration of surgery, length of tissue ischemic time, nutritional status, etc. This is further associated with higher morbidity, the potential for flap failure, higher costs, and increased length of stay in the hospital. This study aimed to determine the factors associated with free flap viability at Dr. Mohammad Hoesin General Hospital, Palembang, Indonesia.&#x0D; Methods: Cross-sectional analytic observational study. A total of 33 research subjects participated in this study. Observation of risk factors was carried out using SPSS univariate and bivariate.&#x0D; Results: Gender and ischemic time factors are related to free flap viability. Male gender and ischemic time &lt; 60 minutes increase the success of free flap viability.&#x0D; Conclusion: Gender and length of ischemic time are associated with free flap viability at Dr. Mohammad Hoesin General Hospital, Palembang, Indonesia.

Relationship between rib cartilage resection and postoperative chest recession deformity in breast reconstruction

The most versatile recipient vessels for breast reconstruction are the internal mammary artery and vein. For microvascular anastomosis, one or two costal cartilages are often dissected to increase the length of the vessel and the degree of freedom. In some cases, the resection of the rib cartilage causes long-term depression at the dissected site, compromising its cosmetic appearance. A total of 101 patients were examined, with 111 sides in which the internal mammary artery and vein were used as the recipient vessels. The patients were followed up for at least 6 months. A total of 37 of 38 patients with complete rib cartilage preservation had no depression, and 1 patient had a slight depression. In the case of partial resection of the rib cartilage, 37 of the 46 sides had no depression, 8 sides had mild depression, and 1 side had an obvious depression. When more than one rib cartilage was removed, 11 of the 27 sides had no depression, 11 had mild depression, and 5 had an obvious depression. The Spearman rank correlation coefficient was 0.4911936. This study reported the relationship between rib cartilage resection and postoperative concave deformity in breast reconstruction surgery using free flap transfer and the internal mammary artery and vein as the recipient vessels. A strong correlation was found between the extent of rib cartilage resected and the degree of depression. Minimizing rib cartilage resection when using the internal mammary artery and veins may minimize postoperative chest recession deformity and provide a well-dressed breast reconstruction.

Are Plastic Surgery Trainees Accurate Assessors of Their Own Microsurgical Skill?

Microsurgery is a technically demanding surgical discipline with a steep learning curve. Trainees have faced several difficulties due to less hands-on theater time and pandemic-related limits on access to technical training. To overcome this, trainees engaged in self-directed training, which requires an accurate self-assessment of skill. This study aimed to assess the ability of trainees to accurately self-assess their performance while performing a simulated microvascular anastomosis. Novice and specialist plastic surgery trainees performed a simulated microvascular anastomosis on a high-fidelity chicken femoral vessel model. Each participant objectively rated the quality of their anastomosis using the Anastomosis Lapse Index (ALI). Two expert microsurgeons subsequently blindly rated each anastomosis. To determine the accuracy of self-evaluation, self-scores and expert-scores were compared using a Wilcoxon signed-rank test. Twenty-seven surgical trainees completed the simulation, with a mean time to completion (TTC) of 40.3 minutes (range 14.2-106.0 minutes). For the entire cohort, the median ALI self-score was 4 (range 3-10), while the median ALI expert-score was 5.5 (range 2.5-9.5). There was a significant difference between the ALI self-score and the expert-score (p<0.001). When grouped by experience level, there was no significant difference between self-score and expert-score within the specialist group, while there was a significant difference within the novice group (p=0.001). These findings suggest that specialist trainees are accurate assessors of their own microsurgical skills, but novice trainees tend to overestimate their technical skills. While novice trainees can engage in independent self-directed microsurgical training, they should seek expert feedback to ensure targeted training.

Head and neck reconstruction in the vessel depleted neck using robot-assisted harvesting of the internal mammary vessels

We report a novel technique of robot-assisted harvesting of the internal mammary vessels to provide effective recipient vessels in a patient with bilateral vessel depleted neck (VDN). A 44-year-old with a Notani grade III osteoradionecrosis (ORN) of the anterior mandible underwent robot-assisted (Da Vinci® Surgical System, Intuitive Surgical) harvesting of the left internal mammary vessels (LIMA, LIMV). Reconstruction of the mandibular defect was done with a virtually planned composite fibular free flap and microvascular anastomosis of the peroneal vessels to the LIMA and LIMV. Successful reconstruction of the anterior mandible was achieved with excellent recipient arterial diameter and length, devoid of any significant thoracic morbidities resulting from robot-assisted harvesting of the internal mammary vessels. Robot-assisted harvesting of internal mammary vessels is a viable alternative to an open approach. The advantages in tissue handling, vessel length, and favourable profile of complications may extend the indications for this otherwise ‘niche’ solution in the VDN.

Lower Extremity Reconstruction with Anterolateral Thigh Free-Flap Anastomoses: A Computational Fluid Dynamic Analysis.

The anterolateral thigh free flap is an option for repairing soft tissue defects of the distal lower extremity. This flap uses the descending branch of the lateral circumflex femoral (LCF) artery as the flap vessel. The recipient vessel in these flaps is often the anterior tibial (AT), posterior tibial (PT), or peroneal (P) arteries. Computational fluid dynamic (CFD) evaluation of anastomoses between these vessels can optimize outcomes. Thirty-eight CFD models were created to model end-to-side (ETS) and end-to-end (ETE) anastomoses for lower extremity reconstruction. Seven out of thirty-eight models represented ETS anastomoses between the LCF and AT arteries with varying anastomotic angles. Nine out of thirty-eight models represented 45-degree ETS anastomoses between varying diameters of the LCF and AT, PT, and P arteries. Nine out of thirty-eight models represented stenosis on the flap vessel and recipient vessel, pre- and post-bifurcation. Nine out of thirty-eight models represented ETE anastomoses, rather than ETS, with varying vessel diameters. Four out of thirty-eight models represented ETE anastomoses with varying regions and levels of stenosis. Stasis of blood flow in ETS models increased as anastomotic angle increased in a logarithmic relationship (R 2 = 0.918). Flow was optimized overall as flap and recipient vessel diameters approached one another. In ETS models, flap vessel and postbifurcation recipient vessel stenosis were found to substantially increase stasis. Selection of flap and recipient vessels with similar diameters can optimize outcomes in microvascular anastomoses. In the context of lower extremity reconstruction with the ALT flap, the PT artery can be recommended as a first-line recipient vessel due to its similar vessel caliber to the LCF and relative ease of surgical access compared with the P artery. Avoidance of areas of stenosis is recommended to ensure laminar flow and reduce the operative difficulty associated with performing anastomoses on nonpliable arteries. Striving for increased acuity of anastomotic angles is recommended to optimize the flow in ETS microvascular anastomoses.

What Is the Minimum Number of Sutures for Microvascular Anastomosis during Replantation?

As vessel diameter decreases, reperfusion after anastomosis becomes more difficult. When a blood vessel is sutured, its inner diameter becomes narrower owing to the thickness of the suture material and the number of sutures. To minimize this, we attempted replantation using a 2-point suture technique. We reviewed cases of arterial anastomosis in vessels with a diameter of less than 0.3 mm during replantation performed over a four-year period. In all cases, close observation was followed by absolute bed rest. If reperfusion was not achieved, a tie-over dressing was applied, and hyperbaric oxygen therapy was administered in the form of a composite graft. Of the 21 replantation cases, 19 were considered successful. Furthermore, the 2-point suture technique was performed in 12 cases, of which 11 survived. When three or four sutures were performed in nine patients, eight of these cases survived. Composite graft conversion was found in three cases in which the 2-point suture technique was used, and two of these cases survived. The survival rate was high in cases where 2-point sutures were used, and there were few cases of conversion to a composite graft. Reducing the number of sutures aids in optimizing reperfusion.

The Use of Retraction Sutures in End-To-Side Microvascular Anastomosis—A Novel Technical Innovation in Experimental Rat Femoral Model with Successful Use in STA-MCA Bypass in Moyamoya Disease

A narrow working space, small diameters, and the tendency to collapse with clamps make cerebral microvascular anastomosis challenging. A retraction suture (RS) is a novel technique to keep the recipient vessel lumen open during the bypass. To provide a step-by-step overview of RS for end-to-side (ES) microvascular anastomosis on rat femoral vessels and successful use for STA-MCA bypass in Moya Moya disease (MMD) patients. A prospective experimental study with approval from the Institutional Animal Ethics Committee. Femoral vessels ES anastomoses were performed on Sprague Daley rats. The rat model used three types of RS (Adventitial, Luminal, and Flap-retraction sutures). An ES-interrupted anastomosis was done. The rats were observed for an average period of 16.18±5.65 days; the patency was assessed by re-exploration. The immediate patency on the STA-MCA bypasses was confirmed with intra-operative indocyanine green (ICG) angiography and micro-doppler; delayed patency with MRI and DSA after 3-6 months. In the rat model, 45 anastomoses were performed, 15 each using the three subtypes. The immediate patency was 100%. Delayed patency was 42/43 (97.67%), and two rats died during observation. In the clinical series, 59 STA-MCA bypasses were done in 44 patients (average age -18.14±11.09 years) using RS. The follow-up imaging was available for 41/59 patients. Both immediate and delayed patency (41/41 at six months) was 100%. The RS allows continuous visualization of the vessel lumen, reduces the handling of intimal edges, and avoids incorporating the back wall in sutures; thus improving anastomosis patency.

Application of a Microsuction Background Device for Microanastomosis in a Rat Femoral Vessel Model.

Microvascular anastomoses can be challenging to perform when edematous fluids and blood continuously flood and compromise the field of view. Intermittent irrigation and suctioning disturb workflow, require an assistant, and can increase risk of arterial thrombosis from vessels being drawn into suction drains. The authors developed and patented a novel three-dimensionally printed background device with microfluidic capabilities to provide autonomous, continuous irrigation and suction to optimize operator autonomy and efficiency. The authors tested this in a rat femoral vessel model. Twelve end-to-end anastomoses were performed by two senior microsurgeons [six conventional, six suction-assisted background (SAB)] in a rat femoral artery model. The primary outcome was time taken to complete the anastomosis. Secondary outcomes included the validated Structured Assessment of Microsurgery Skills (SAMS) score and the total number of "wiping" events to obtain field clarity. Each procedure was recorded, and videos were independently rated by two blinded experts using the SAMS score. Time taken to complete the anastomosis was greater in the conventional group compared with the SAB group (741.7 ± 203.1 seconds versus 584 ± 155.9 seconds; P = 0.007). The median SAMS score was lower in the conventional group compared with the SAB group (32.3 ± 1.4 versus 38.3 ± 1.5; P = 0.001). The median number of wiping events was significantly greater in the conventional group compared with the SAB group (13 ± 2.2 versus 1.7 ± 1.2; P < 0.001). The authors show that a novel microfluidic background device allows continuous irrigation and suctioning without the need for an assistant, optimizing the efficiency of the microvascular anastomosis. The authors have designed a novel, patented, three-dimensionally printed microsurgical background device that provides continuous irrigation and suction, reduces operative time, and provides better vessel clarity during a microsurgical anastomosis compared to standard background.

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

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