End-to-end and end-to-side microvascular anastomoses: a comparative study

End-to-side Anastomosis on Digital Arteries: Just a Technical Choice or a Real Benefit?

High-quality evidence is currently poor regarding the benefits of end-to-end (ETE) or end-to-side (ETS) anastomosis in arterial and venous anastomoses, despite being postulated as a potential influence on outcomes. A sufficient microvascular anastomosis is indispensable for the success of any free tissue transfer. ETS microvascular anastomoses have been becoming increasingly important as they allow reconstruction even in patients with impaired vascular status. To the authors’ knowledge, no studies have examined the choice of ETE or ETS anastomoses specifically for digital arteries.

Surgical treatment options for septic non-union of the tibia: two staged operation, Flow-through anastomosis of FVFG, and continuous local intraarterial infusion of heparin

BACKGROUND

The treatment of septic non-union of the tibia is a challenging area.　The objective of this clinical study was to improve the treatment outcomes in patients with a highly active infection by the three strategies consisting of a two-staged operation, a flow-through technique for vascular anastomosis of a free vascularized fibular graft (FVFG), and continuous local intra-arterial infusion of heparin.

PATIENTS & METHOD

Five patients with septic non-union of the tibia who were treated with an FVFG (mean age: 52.8 years) were enrolled.　The mean postoperative follow-up period was 47.2 months, and the mean length of the bone defect was 111 mm.　A two-staged operation, in which polymethylmethacrylate (PMMA) beads containing antibiotics were inserted into a bone defect followed by bone reconstruction performed with an FVFG later.　Vascular anastomosis was performed with the flow-through technique in all patients.　Immediately after FVFG, heparin was continuously infused through a femoral arterial catheter for 1 week.

RESULT

Bone union was confirmed an average of 18.8 weeks after-surgery in all patients without reoperation for thrombus.

CONCLUSION

Our attempt to apply the strategies appears to be a viable treatment option for septic non-union of the tibia.

Limb salvage and vascular augmentation by microsurgical free flap transfer for treatment of neuropathic diabetic foot ulcers

BACKGROUND

Neuropathic diabetic foot ulcers are generally deep and infectious wounds extending to the bone or joint. We performed microsurgical free flap transfer for limb salvage and vascular augmentation of feet with diabetic neuropathy.

METHODS

Angiography was performed to identify any significant arterial disease. The free flaps were transplanted after resection of the damaged skin and infected bone. Flow-through or end-to-side anastomosis to the dorsalis pedis artery was performed to preserve the arterial blood flow to the residual foot.

RESULTS

An anterolateral thigh flap and free flaps based on the subscapular artery system were transplanted in 1 and 10 patients, respectively. All flaps survived. Arterial flow on the distal side of the anastomosis was postoperatively confirmed in all patients. During a mean follow-up period of 52 months, the long-term complications observed were recurrent ulcers in 4 patients. The limb salvage rate was 100%, and 82% of patients achieved functional ambulation.

CONCLUSIONS

Microsurgical flap transplantation is a safe and useful technique for minimal amputation of a diabetic neuropathic foot. Postoperative protection of the feet is important in order to avoid recurrence of foot ulceration. The use of protective footwear custom-tailored for each patient is strongly recommended.

Free versus perforator-pedicled propeller flaps in lower extremity reconstruction: What is the safest coverage? A meta-analysis

INTRODUCTION

Currently, increasingly reconstructive surgeon consider the failure rates of perforator propeller flaps especially in the distal third of the lower leg are too important and prefer to return to the use of free flap at first line option with failure rates frequently lower than 5%. So, we performed a systematic review with meta-analysis comparing free flaps (perforator-based or not) and pedicled-propeller flaps to respond to the question "what is the safest coverage for distal third of the lower limb?"

METHODS

This review was conducted according to PRISMA criteria. From 1991 to 2015, MEDLINE®, Pubmed central, Embase and Cochrane Library were searched. The pooled estimations were performed by meta-analysis. The homogeneity Q statistic and the I² index were computed.

RESULTS

We included 36 articles for free flaps (1,226 flaps) and 19 articles for pedicled-propeller flaps (302 flaps). The overall failure rate was 3.9% [95%CI:2.6-5.3] for free flaps and 2.77% [95%CI:0.0-5.6] for pedicled-propeller flaps (P = 0.36). The complication rates were 19.0% for free flaps and 21.4% for pedicled-propeller flaps (P = 0.37). In more detail, we noted for free flaps versus pedicled-propeller flaps: partial necrosis (2.70 vs. 6.88%, P = 0.001%), wound dehiscence (2.38 vs. 0.26%, P = 0.018), infection (4.45 vs. 1.22%, P = 0.009). The coverage failure rate was 5.24% [95%CI:3.68-6.81] versus 2.99% [95%CI:0.38-5.60] without significant difference (P = 0.016).

CONCLUSION

In the lower limb the complications are not rare and many teams consider the free flaps to be safer. In this meta-analysis we provide evidence that failure and overall complications rate of perforator propeller flaps are comparable with free flaps. Although, partial necrosis is significantly higher for pedicled-propeller flaps than free flaps, in reality the success of coverage appears similar. © 2016 Wiley Periodicals, Inc. Microsurgery, 38:109-119, 2018.

Use of fibula flaps to treat persistent talonavicular nonunion: A report of three cases

Owing to the limited blood supply in the midfoot, multiple arthrodesis attempts in midfood joints may result in severe osteonecrosis, leading to a difficult scenario for bone reconstruction. This article describes the use of fibula flaps (two free and one pedicled flap) to reconstruct bone defects in three cases of persistent nonunion in midfoot joints. Before admission, all patients (aged 32-56 years old) had undergone multiple arthrodesis attempts (range 3-4) aimed at treating joint diseases associated with flatfoot or Müller-Weiss syndrome. All inserted flaps were stable, and bone fusion was confirmed by X-ray examination at month 4. After the follow-up period (range 1-4 years), all patients showed normal, painless gait. No foot deformities or further complications were observed. Our report suggests that fibula flap transfer may be a good alternative for treating persistent nonunion in midfoot joints involving bone loss, and may prevent the osteonecrosis associated with limited blood supply. © 2016 Wiley Periodicals, Inc. Microsurgery 36:430-434, 2016.

Free flap transfer to preserve main arterial flow in early reconstruction of open fracture in the lower extremity

The selection of recipient vessels is crucial when reconstructing traumatized lower extremities using a free flap. When the dorsalis pedis artery and/or posterior tibial artery cannot be palpated, we utilize computed tomography angiography to verify the site of vascular injury prior to performing free flap transfer. For vascular anastomosis, we fundamentally perform end-to-side anastomosis or flow-through anastomosis to preserve the main arterial flow. In addition, in open fracture of the lower extremity, we utilize the anterolateral thigh flap for moderate soft tissue defects and the latissimus dorsi musculocutaneous flap for extensive soft tissue defects. The free flaps used in these two techniques are long and include a large-caliber pedicle, and reconstruction can be performed with either the anterior or posterior tibial artery. The preparation of recipient vessels is easier during the acute phase early after injury, when there is no influence of scarring. A free flap allows flow-through anastomosis and is thus optimal for open fracture of the lower extremity that requires simultaneous reconstruction of main vessel injury and soft tissue defect from the middle to distal thirds of the lower extremity.

Opened end-to-side technique for end-to-side anastomosis and analyses by an elastic true-to-scale silicone rubber model

The end-to-side anastomosis is frequently used in microvascular free flap transfer, but detailed rheological analyses are not available. The purpose of this study was to introduce a new modified end-to-side (Opened End-to-Side, OES-) technique and compare the resulting flow pattern to a conventional technique. The new technique was based on a bi-triangulated preparation of the branching-vessel end, resulting in a "fish-mouthed" opening. We performed two different types of end-to-side anastomoses in forty pig coronary arteries and produced one elastic, true-to-scale silicone rubber model of each anastomosis. Then we installed the transparent models in a circulatory experimental setup that simulated the physiological human blood flow. Flow velocity was measured with the one-component Laser-Doppler-Anemometer system, recording flow axial and perpendicular to the model at four defined cross-sections for seven heart cycles in each model. Maximal and minimal axial velocities ranged in the conventional model between 0.269 and -0.122 m/s and in the experimental model between 0.313 and -0.153 m/s. A less disturbed flow velocity distribution was seen in the experimental model distal to the anastomosis. The OES-technique showed superior flow profiles distal to the anastomosis with minor tendencies of flow separation and represents a new alternative for end-to-side anastomosis.

Reconstruction of the lower extremity using free flaps

Background

The aim of lower-extremity reconstruction has focused on wound coverage and functional recovery. However, there are limitations in the use of a local flap in cases of extensive defects of the lower-extremities. Therefore, free flap is a useful option in lower-extremity reconstruction.

Methods

We performed a retrospective review of 49 patients (52 cases) who underwent lower-extremity reconstruction at our institution during a 10-year period. In these patients, we evaluated causes and sites of defects, types of flaps, recipient vessels, types of anastomosis, survival rate, and complications.

Results

There were 42 men and 10 women with a mean age of 32.7 years (range, 3-72 years). The sites of defects included the dorsum of the foot (19), pretibial area (17), ankle (7), heel (5) and other sites (4). The types of free flap included latissimus dorsi muscle flap (10), scapular fascial flap (6), anterolateral thigh flap (6), and other flaps (30). There were four cases of vascular complications, out of which two flaps survived after intervention. The overall survival of the flaps was 96.2% (50/52). There were 19 cases of other complications at recipient sites such as partial graft loss (8), partial flap necrosis (6) and infection (5). However, these complications were not notable and were resolved with skin grafts.

Conclusions

The free flap is an effective method of lower-extremity reconstruction. Good outcomes can be achieved with complete debridement and the selection of appropriate recipient vessels and flaps according to the recipient site.

Autologous microsurgical breast reconstruction and coronary artery bypass grafting: an anatomical study and clinical implications

OBJECTIVE

To identify possible avenues of sparing the internal mammary artery (IMA) for coronary artery bypass grafting (CABG) in women undergoing autologous breast reconstruction with deep inferior epigastric artery perforator (DIEP) flaps.

BACKGROUND

Optimal autologous reconstruction of the breast and coronary artery bypass grafting (CABG) are often mutually exclusive as they both require utilisation of the IMA as the preferred arterial conduit. Given the prevalence of both breast cancer and coronary artery disease, this is an important issue for women's health as women with DIEP flap reconstructions and women at increased risk of developing coronary artery disease are potentially restricted from receiving this reconstructive option should the other condition arise.

METHODS

The largest clinical and cadaveric anatomical study (n=315) to date was performed, investigating four solutions to this predicament by correlating the precise requirements of breast reconstruction and CABG against the anatomical features of the in situ IMAs. This information was supplemented by a thorough literature review.

RESULTS

Minimum lengths of the left and right IMA needed for grafting to the left-anterior descending artery are 160.08 and 177.80 mm, respectively. Based on anatomical findings, the suitable options for anastomosis to each intercostals space are offered. In addition, 87-91% of patients have IMA perforator vessels to which DIEP flaps can be anastomosed in the first- and second-intercostal spaces.

CONCLUSION

We outline five methods of preserving the IMA for future CABG: (1) lowering the level of DIEP flaps to the fourth- and fifth-intercostals spaces, (2) using the DIEP pedicle as an intermediary for CABG, (3) using IMA perforators to spare the IMA proper, (4) using and end-to-side anastomosis between the DIEP pedicle and IMA and (5) anastomosis of DIEP flaps using retrograde flow from the distal IMA. With careful patient selection, we hypothesize using the IMA for autologous breast reconstruction need not be an absolute contraindication for future CABG.

From simple interrupted to complex spiral: a systematic review of various suture techniques for microvascular anastomoses

Accomplishing successful microvascular anastomoses is undoubtedly one of the most critical steps in performing free tissue transfer. However, the ideal technique has often been a subject of debate. Therefore, our objective was to review the current literature in an attempt to find objective evidence supporting the superiority of one particular technique. A PubMed and OVID on-line search was performed in November 2007 using the following keywords: microvascular anastomoses, microsurgical anastomosis, continuous suture, interrupted suture, mattress suture, and sleeve anastomosis. Our literature review found no difference in short- and/or long-term patency rates between the six main published techniques, which includes continuous suture, interrupted suture, locking continuous, continuous horizontal, horizontal interrupted with eversion, and sleeve anastomoses. These findings were consistent for each technique as long as the microsurgeon maintained standard microsurgical principles and practice, including suture line eversion, minimized tension, and direct intima-to-intima contact. Current literature supports no overall statistical difference in short- and/or long-term patency rates between any of the various techniques. The choice to perform one suture technique over another ultimately depends on the plastic surgeon's preference and microsurgical experience. To date, there are no human randomized, controlled clinical trials comparing the efficacy and clinical outcomes of each of the various suture techniques, and therefore one's comfort and familiarity should dictate his or her microsurgical technique. However, "exposure to many and mastery of one" simply provides the plastic surgery resident, fellow, or staff the technical flexibility needed for less-complicated surgical planning when performing free tissue transfer.

Microvascular free tissue transfer in reconstruction of the lower limb

Reconstruction of the lower extremity using microvascular free tissue transfer has been adopted as a routine procedure since the 1980s. Success rates in overall free tissue transfer are now as high as 98%. In the lower limb, however, the failure rate has been reported to be as high as 15 to 20%. A review of 50 consecutive microvascular free flaps to the lower extremity was carried out in the Ulster Hospital Belfast. The indication for surgery, the flap type, the recipient vessel, re-exploration rate, complication rate, success rate and the changing pattern in management during the first six years of a single consultant's practice was assessed. Six patients (12%) were re-explored for anastomotic complications or haematoma. Thrombosis of the arterial anastomosis was noted in one case, venous thrombosis in two and haematoma under the flap in the remaining three cases. Salvage was successful in four cases, thus producing an overall success rate of 96%.

How to deal with difficult microsurgical end-to-side anastomoses

Although unexplained thrombotic failures still exist, the majority of free-flap failures are due to identifiable technical failures, indicating that an excellent operative technique remains the key point. However, some clinical circumstances, such as damaged or deeply located vessels, are related to a higher thrombotic risks, demanding refinements of the microsurgical procedure to avoid higher failure rates. We reviewed 195 free flaps in the lower leg in order to quantify these situations and how we dealt with them. In total, six flaps were performed with a T-interposition to cope with difficult end-to-side anastomoses on damaged vessels. In two cases, the use of a funnel-shaped vein graft facilitated difficult end-to-side anastomoses in the popliteal area. The authors believe that these refinements of microsurgery should not be first-choice procedures, but they have proven to be a useful tool for certain microsurgical reconstructions.

End-to-end versus end-to-side arterial anastomosis patency in microvascular surgery

The patency rates of microsurgical end-to-end and end-to-side anastomosis in the rat carotid artery were studied. Seventy end-to-end and seventy end-to-side arterial anastomoses, using 10-0 nylon interrupted sutures, were performed on 140 Sprague-Dawley rats. Findings indicated 100% patency in end-to-end as well as end-to-side immediately and 1 week post-anastomosis. This investigation suggests that there is no significant advantage between the methods studied based on vessel patency alone. The decision to perform an end-to-end vs. an end-to-side arterial anastomosis should be based upon the clinical circumstances encountered, since no significant difference in patency rates exists.

Patency of different arterial and venous end-to-side microanastomosis techniques in a rat model

Microvascular anastomotic patency is the most important factor in determining a successful outcome in free-flap transfers. End-to-end and end-to-side techniques have been shown to provide equivalent arterial patency rates in clinical and basic science studies, and end-to-side anastomoses have been used extensively in microsurgical reconstruction. Nevertheless, the effect of venotomy shape on the patency of venous end-to-side anastomoses has not been previously reported. The purpose of this study was to compare the patency rates of end-to-side anastomoses using different techniques in both arteries and veins. In total, 104 Sprague-Dawley rats were subdivided into four groups. The rats were anesthetized, and anastomosis was performed on either the femoral artery or vein on the right with the left used as control. Vesselotomy was varied between an end-to-side hole and an end-to-side slit with patency measured immediately following surgery and at 2 weeks. No significant difference in patency or histology between these techniques was demonstrated in any group. We conclude there is no difference in patency rate between the two techniques in arterial or venous vesselotomies; however, in small vessels < 1.5 mm, the slit technique is technically easier, and clinical recommendations are given.

Hemodynamic study of different angled end-to-side anastomoses

This study assessed the postoperative microvascular hemodynamics in end-to-side arterial anastomoses of varied angles in order to determine whether the angle of the anastomosis affects arterial flow. Thirty male rats were divided into three groups of ten. Carotid to carotid end-to-side anastomoses were performed with anastomotic angles of 45, 90, and 135 degrees. Postoperative flow was assessed using high frequency pulsed Doppler ultrasound (HFPDU) at 30 and 120 min postoperatively. Measurements at 30 min demonstrated significant differences in flow, with the 45 degrees grafted vessels utilizing 56.5% of total carotid flow, and the 90 degrees and 135 degrees anastomoses appropriating 46.5% and 43.2% of flow, respectively (comparing 45 degrees to both 90 degrees, P < 0.05, and 135 degrees, P < 0.002). The change from baseline in 45 degrees and 90 degrees groups dissipated over a 2 hr postoperative period, but flow in the grafted vessels in the 135 degrees group continued well below 50% at 39.9% (comparing to both 45 degrees and 90 degrees, P < 0.001), thereby displaying a significant difference in the postoperative arterial flow of varied angled microanastomoses.

Prefabrication of free flaps using the omentum in rats

The omentum used as a vascular carrier is a new experimental model for prefabrication of free flaps in the rat. A 2.5 x 4 cm patch of omentum with gastroepiploic vessels and its rich vascular arcades was transferred under a bipedicled 2.5 x 6 cm right abdominal panniculocutaneous flap. At subsequent time intervals (postoperative days 0, 3, 5, 7, and 14), the skin pedicles were divided and the skin flap was raised as a composite island flap vascularized only by the underlying omental patch. The composite flap was then sutured back in place. Prefabricated flaps examined postoperatively demonstrated a dye fluorescence index (DFI) of 4.60% +/- 2.82% and 1.67% +/- 4.08% flap survival (FS) in the day 0 group; in the day 3 group, 9.83% +/- 1.47% of DFI and 15.00% +/- 10.35% of FS; in the day 5 group, 28.39% +/- 5.25% of DFI and 86.0% +/- 12.74% of FS (P less than 0.05); in the day 7 group, 38.19% +/- 7.52% of DFI and 98.13% +/- 3.72% of FS (P less than 0.05); and, in the day 14 group, 49.55% +/- 6.70% of DFI and 100% of FS (P less than 0.05). India-ink injection and histologic examination confirmed revascularization of the overlying skin by day 5.

Toe transfer for congenital hand defects

Toe-to-hand transfer is a well-established reconstructive option for certain congenital hand anomalies. It is the only technique which can add growth potential to the immature skeleton. Toe transfer is best suited for constriction ring amputations, which have relatively normal proximal anatomy. Transfers should be performed early in life to avoid lack of cortical integration of the new part. Anatomic variations of both hand and foot are often encountered, which influence both operative approach and functional prognosis. Indications, techniques, and complications are reviewed.

In search of the "perfect" anastomosis

Forty-five end-to-side microvascular anastomoses were completed in rat carotid arteries of 0.7-0.8 mm diameter (anastomosing the distal end of the left common carotid to the side of the right common carotid). For comparison both 10-0 and 11-0 sutures were utilized in different anastomotic techniques: interrupted, direct-continuous, and diagonal-continuous sutures, plus total mural thickness vs. partial mural thickness (piercing only the adventitia and outer media, excluding the intima). Anastomoses were evaluated for patency and scanning electron microscopic appearance after 10 to 12 weeks. The results indicate complete patency in all anastomoses. Ultrastructural observations revealed nearly normal intimal appearance in the partial medial technique and only minimal evidence of intimal injury in the other techniques. It is concluded that 100% patency can be obtained regardless of suture size or anastomotic technique. The most important factor in anastomotic patency is the operator's technical skill.

Angled side wall microarteriotomy scissors: a new end-to-side microvascular anastomosis instrument

Creation of a smooth side wall arteriotomy for an end-to-side microsurgical anastomosis can at times be difficult and time consuming. To facilitate this maneuver, a new end-to-side microarteriotomy scissor was designed for creation of recipient vessel openings from 0.5-2 mm in size. These new scissors and their recommended use are described.