Venous Superdrainage Research Articles

Acromiothoracic Venous Supercharge for Abdominal-Based Free Flaps in Breast and Chest Wall Reconstruction

Background Supercharging the venous drainage of free abdominal flaps in breast reconstruction has been well described in the literature, with diverse options used to augment venous drainage. In this study, we present our experience in using the acromiothoracic vein (ATV)/thoracoacromial vein (TAV) as a secondary recipient vein for the superficial inferior epigastric vein (SIEV) of free, muscle-sparing transverse rectus abdominis myocutaneous flaps in breast and chest wall reconstruction. Patients and Methods We retrospectively reviewed 523 free, muscle-sparing transverse rectus abdominis myocutaneous flaps the senior author (H.H.K.) performed between 2009 and 2022 for breast and chest wall reconstruction; 46 cases required venous super drainage. Seventeen patients had ipsilateral SIEV anastomosed into the second internal mammary vein, 5 had ipsilateral SIEV anastomosed into flap second deep inferior epigastric vein, and 24 required the use of the (ATV)/(TAV), which will be the focus of this study. Results The study included 24 female (20 breast and 4 chest wall reconstruction) patients ranging in ages between 39 and 72 years. They had a median follow-up of 26 months. Combined muscle splitting and cutting techniques were used to expose the ATV/TAV. Increase in operative time ranged between 10 and 20 minutes (median, 12 minutes). Vein coupler sizes were 1.5 to 3 mm. The mean weight of the flap was 740 g (range, 460–1300 g). There was 1 flap failure (salvage with latissimus dorsi flap performed), whereas 23 flaps wholly survived. Conclusions The ATV/TAV is a suitable recipient for venous supercharging free flaps used to reconstruct breast and chest wall defects.

Efficacy of superficial inferior epigastric vein superdrainage in free TRAM and DIEP flap: An indocyanine green angiography study of 68 cases

This study aimed to evaluate the clinical efficacy of venous augmentation using superficial inferior epigastric vein (SIEV) in free transverse rectus abdominis musculocutaneous (TRAM) and deep inferior epigastric artery perforator (DIEP) flap and investigate the factors that hinder the venous superdrainage. A retrospective review of 62 free muscle-sparing (MS)-TRAM and 6 DIEP unilateral breast reconstructions from September 2017 to July 2022. Intraoperative indocyanine green angiography was performed on the harvested flap, with the SIEV contralateral to the pedicle side clamped and unclamped for 20min. The relative ratio of hypoperfused area to the total flap area was calculated and compared quantitatively. The preoperative computed tomography (CT) angiography was reviewed to obtain information on the SIEV diameter and number of midline-crossing medial branches. The participants were categorized into three groups: 42 patients in Group 1 (>3% decrease in hypoperfused area), 20 patients in Group 2 (change in hypoperfused area ranging from -3% to 3%), and six patients in Group 3 (>3% increase in hypoperfused area). The mean number of midline-crossing branches (p=0.002) and mean difference in the diameter of bilateral SIEVs (p=0.039) were significantly greater in Group 1 than in the other groups. Thirty-eight percent (26/68 cases) resulted in sustained or aggravated perfusion after SIEV superdrainage. Superdrainage using the contralateral SIEV in free MS-TRAM/DIEP flap is recommended when there are more than two midline-crossing medial branches of SIEV and when the caliber of SIEV is relatively greater compared with the pedicle side.

Further study of hemodynamics in the distal end of multi-territory perforator flap

To summarize and discuss the key factors affecting the hemodynamics in the distal end of the multi-territory perforator flap, so as to provide a theoretical basis for the follow-up research and clinical application in this field. The related recent literature about multi-territory perforator flaps was extensively reviewed, and the concepts and researches of perforasome, choke vessel zone, arterial super-charge, and venous super-drainage were summarized. The multi-territory perforator flap is composed of multiple perforasomes, and there are different types of vascular anastomosis in the choke vessel zones, which have important impacts on the hemodynamics of the flap. In order to ensure the survival of the multi-territory perforator flap, arterial super-charge and venous super-drainage are mainly used in clinical practice. However, no consensus has been reached on the choice of the two techniques. The different distribution of blood vessels in the flap, the number of perforasomes, and the type of vascular anastomosis may be the main reasons for the different results. The location, diameter, and axial characteristics of perforators, the number of perforasomes, and the type of vascular anastomosis are the key factors affecting the hemodynamics of the multi-territory perforator flaps, which should be paid attention to in preoperative design and surgical procedure.

Effects of Distal Arterial Supercharging and Distal Venous Superdrainage on the Survival of Multiterritory Perforator Flaps in Rats

Background Which one of the two measures, distal arterial supercharging (DAS) and distal venous superdrainage (DVS), is better to enhance flap survival? No consistent conclusions have been reached. Methods All flaps were pedicled on the deep circumflex iliac vessels. Seventy-two healthy male rats were distributed to four groups randomly: DAVS group (distal arteriovenous supercharging group), the thoracodorsal (TD) artery and TD vein were preserved; DAS group (distal arterial supercharging group), the TD vein was ligated; DVS group (distal venous superdrainage group), the TD artery was ligated; control group, the TD artery and TD vein were ligated. Flap survival rate was evaluated on postoperative day 7. Flap angiography was performed to assess vascular changes of the flap. Microvascular density (MVD) was evaluated by hematoxylin and eosin staining, and CD34-positive microvessel density was measured by immunohistochemistry. Vascular endothelial growth factor (VEGF) level was measured by western blot. The levels of superoxide dismutase (SOD) and malondialdehyde (MDA) were evaluated using specialized commercial kits. Results The mean flap survival rate was increased significantly in DAVS and DAS groups than in DVS and control groups. DAVS and DAS groups had higher flap vascularization, MVD, CD34-positive microvessel density, VEGF expression and SOD level compared to DVS and control groups. DAVS and DAS groups also had lower MDA level relative to DVS and control groups. Conclusion DAS is more conducive to improving the survival rate of the multiterritory perforator flap compared to DVS, mainly by enhancing angiogenesis and preventing ischemia-reperfusion (I/R) injury.

Liberal versus Modified Intraoperative Fluid Management in Abdominal-flap Breast Reconstructions. A Clinical Study.

Background:The outcome of reconstructive microsurgery is influenced by the intraoperative anesthetic regimen. The aim of this study was to compare the impact on the intra- and postoperative complication rates of our modified fluid management (MFM) protocol with a previously used liberal fluid management protocol in abdominal-flap breast reconstructions.Methods:This retrospective study analyzed adverse events related to secondary unilateral abdominal-flap breast reconstructions in two patient cohorts, one with a liberal fluid management protocol and one with a MFM protocol. In the MFM protocol, intravenous fluid resuscitation was restricted and colloid use was minimized. Both noradrenaline and propofol were implemented as standard in the MFM protocol. The primary endpoints were surgical and medical complications, as observed intraoperatively or postoperatively, during or shortly after the hospital stay.Results:Of the 214 patients included in the study, 172 patients followed the MFM protocol. Prior radiotherapy was more frequent in the MFM protocol. Surgical procedures to achieve venous superdrainage were more often used in the MFM cohort. Intraoperative as well as postoperative complications occurred significantly more frequently in the liberal fluid management cohort and were specifically associated with partial and total flap failures. Prior radiotherapy, additional venous drainage, or choice of inhalation agent did not have an observable impact on outcome.Conclusions:The incidence of adverse events during and after autologous breast reconstructive procedures was reduced with the introduction of an MFM protocol. Strict intraoperative fluid control combined with norepinephrine and propofol was both beneficial and safe.

Venous superdrainage using superficial circumflex iliac vein in deep circumflex iliac artery perforator flap with iliac crest for oromandibular reconstruction

The deep circumflex iliac artery perforator flap with iliac crest (DCIAPF) is considered a favourable single-flap option for oromandibular reconstruction. The aim of this study was to evaluate the effectiveness of venous superdrainage using the superficial circumflex iliac vein (SCIV) in the DCIAPF for oromandibular reconstruction. The data of 22 patients (12 female, 10 male) aged 10–76 years (median 53 years) who underwent simultaneous oromandibular reconstruction with a DCIAPF were reviewed retrospectively. Eleven patients received the DCIAPF with SCIV for superdrainage (group A) and another 11 patients received the conventional single-pedicled DCIAPF flap (group B). No flap loss occurred in either group. Venous congestion due to relative venous insufficiency was significantly more frequent in group B (P=0.045). There was no significant difference in the incidence of partial flap necrosis and wound dehiscence, or in the total operation time between the two groups. Superdrainage using the SCIV has the potential to reduce the incidence of venous congestion due to relative venous insufficiency in DCIAPF used for oromandibular reconstruction.

Improvement of multiterritory perforator flap survival supported by a hybrid perfusion mode: A novel strategy and literature review

Perforator flaps have been widely used in clinical Settings, however, unexpected necrosis was still commonly encountered in the distal portions of multiterritory flaps known as Choke zone III. In this study, we introduced a novel hybrid perfusion technique which is different from the established one of arterial supercharging or venous superdrainage to improve multiterritory flap survival with success. In order to ensure the entire flap survival of multiterritory flaps extending to choke zone III, a “hybrid perfusion” mode by anastomosing a distal vein of the flap with a recipient artery was carried out in two cases based on our previous basic study. In addition, a systematic literature review regarding the established microsurgical assistant techniques of arterial supercharging and venous superdrainage techniques were performed. Both flaps survived uneventfully. At a minimal follow-up of six months, both patients were satisfied with the results. This novel hybrid perfusion technique provides a simple new concept in solving partial necrosis of multiterritory flaps. Further practice is guaranteed for better understanding this unconventional attempt.

Meta-analysis of the effects of venous super-drainage in deep inferior epigastric artery perforator flaps for breast reconstruction.

Venous congestion is the most common vascular complication of the deep inferior epigastric artery perforator (DIEP) flaps. Adding a second venous drainage by anastomosing a flap vein and a recipient vein (super-drainage) is considered the solution of choice. Evidence to support this procedure, had not yet been confirmed by an analysis of the literature. We aimed to provide this evidence. We searched the literature (MedLine, Scopus, EMBASE, Cochrane Library, and Google Scholar), for studies discussing venous congestion and venous super-drainage in DIEP flap for breast reconstruction. Thirteen of the 35 articles compared results between one or two venous anastomoses. Meta-analysis was performed following PRISMA guidelines. Pooled risk ratio (RRs) for congestion, fat necrosis, partial necrosis, and total necrosis with corresponding 95% confidence intervals (CI) were calculated using a fixed-effect model with the Mantel-Haenszel method. The need to return to surgery (95% CI) was estimated with a random effect model using the DerSimonian and Liard method. We showed a statistically significant advantage of super-drainage to reduce the venous congestion of the flap (RR: 0.12, 95% CI: 0.04-0.34, p-value <.001), partial flap necrosis (RR: 0.50, 95% CI: 0.30-0.84, p-value .008), total flap necrosis (RR: 0.31, 95% CI: 0.11-0.85, p-value .023), and the need to take the patient back to surgery for perfusion-related complications (RR: 0.45, 95% CI: 0.21-0.99, p value .048). Performing a second venous anastomosis between the SIEV and a recipient vein (venous superdrainage) reduces venous congestion and related complications in DIEP flaps for breast reconstruction.

Comparison of arterial supercharging and venous superdrainage on improvement of survival of the extended perforator flap in rats.

Arterial supercharging and venous superdrainage have been the commonly used vascular augmentation techniques for resolving partial loss of flaps in reconstructive surgery. It remains controversial which one of them is more effective in improving flap survival. The purpose of this study was to compare the effect of distal venous superdrainage and arterial supercharging on the survival of an extended dorsal perforator flap in rats. Sixty Sprague-Dawley rats were randomly divided into three groups (n = 20 in each group). An extended dorsal perforator flap with the size of 3 × 12 cm based on the deep circumflex iliac artery and vein was elevated in each rat. In arterial supercharging group, the thoracodorsal artery was retained as the distal supercharging vessel; In venous superdrainage group, the thoracodorsal vein was retained as the distal superdrainage vessel. In control group, no other arteries and veins were retained except the main vascular pedicle. On the seventh day after operation, the survival area of flap was calculated as a percentage of viable area to the total flap. Vascular changes in the choke zones were assessed by angiography. Microvascular density and diameter were assessed via immunohistochemistry staining of CD31 on the fifth day after operation. The flap survival area in arterial supercharging group was significantly higher than that in venous superdrainage group (98.9 ± 0.8% vs. 81.5 ± 3.5%, p < .001). By gross observation, the extent of dilation of choke zone vessels in venous superdrainage group was smaller compared with that in arterial supercharging group. The density of CD31-positive vessels and the diameter of choke zone vessels in arterial supercharging group were significantly larger than that in venous superdrainage group (23.4 ± 4.6 mm-2 vs. 13.1 ± 4.2 mm-2 , p < .05; and 37.5 ± 5.8 μm vs. 27.8 ± 4.9 μm, p < .05). Compared with venous superdrainage, distal arterial supercharging in the potential territory resulted in better survival of an extended dorsal perforator flap in a rat model.

Different Hydraulic Constructs to Optimize the Venous Drainage of DIEP Flaps in Breast Reconstruction: Decisional Algorithm and Review of the Literature.

Venous congestion is the most common perfusion-related complication of deep inferior epigastric artery perforator (DIEP) flap. Several hydraulic constructs can be created for venous superdrainage in case of flap venous engorgement or as a preventive measure. These can be classified based on the choice of the draining vein of the flap, either a second deep inferior epigastric vein (DIEV) or a superficial inferior epigastric vein (SIEV), and of the recipient vein, either a vein of the chest or the DIEV. We conducted a comprehensive systematic literature review in Medline, Scopus, EMBASE, Cochrane Library, and Google Scholar to find publications that reported on venous congestion in DIEP flap. The keywords used were DIEP Flap, breast reconstruction, venous congestion, supercharging, superdrainage, SIEV, and DIEV. Based on the studies found in the literature, we developed an algorithm to guide the surgeon's decision when choosing the veins for the superdrainage anastomosis. Several alternatives for venous anastomosis in superdrainage are available. We propose an algorithm to simplify the choice. The use of the ipsilateral SIEV to be connected to a vein of the chest appears to be advantageous. The anatomical position that allows the easiest anastomosis dictates which chest vein to favor.

The practice of breast reconstruction with abdominal tissue in a Hong Kong high caseload centre

AbstractAimIn the recent few years, the breast centre of Hong Kong West Cluster, that is Queen Mary Hospital and Tung Wah Hospital, has had the highest caseload of breast reconstruction among all hospitals in the Hospital Authority. Immediate breast reconstruction with abdominal tissue is the most common surgery performed for our breast cancer patients. In this article, the goal and timing of reconstruction, various reconstructive options, our experience in breast reconstruction using abdominal tissue and the extra microvascular procedures are described.Patients and MethodsFrom January 2016 to December 2018, 155 female patients underwent breast reconstruction. The mean age was 46.5 (range 32–68 years). All required total mastectomy as the treatment of breast cancer.ResultsA total of 163 breast reconstructions were performed in our unit. 153 (93.9%) were reconstructions with autologous tissue, 10 (6.1%) were pure implant reconstructions. Of the 153 autologous tissue reconstructions, 123 (80.4%) were abdominal tissue reconstructions and 30 (19.6%) were latissimus dorsi myocutaneous flap reconstructions.ConclusionsAbdomen is the most popular donor site of autologous tissue for breast reconstruction. Pedicled transverse rectus abdominis myocutaneous (TRAM) flap and free deep inferior epigastric perforator flap are the reliable flap options. Venous superdrainage is an extra procedure that was performed routinely in TRAM breast reconstruction to reduce the incidence of venous congestion.

Arterial Supercharging Is More Beneficial to Flap Survival Due to Quadruple Dilation of Venules

Background“Choke vessels” are communicating conduits between adjacent perforasomes in the skin. Most researches focus mainly on the arterial aspect of the “choke vessels” and neglect the venous aspect, an imbalance needed to be addressed. Materials and methodsThe study was divided into parts I, II, and III. Part I was for observation of the vascular morphological evolution in the choke zone after flap harvest in rats. Part II was for determination of the importance of the dilation of the arterial and venous components of “choke vessels” by preserving the iliolumbar artery (ILA group) or vein (ILV group). A laser Doppler flowmeter and a speckle flow imaging system were adopted for monitoring the hemodynamic impact caused by the different manipulation. Part III was for corroboration of part II by manipulation of other vessels. ResultsIn part I, the arteries and veins between the iliolumbar and intercostal perforasomes underwent modest dilation, whereas the venules between the veins nearly quadrupled in diameter. In part II, flaps in the ILA group were much more intensive in blood perfusion than flaps in the ILV group. The flap necrosis rate was 0.31 ± 0.07 in the ILV group, being significantly larger than 0.10 ± 0.03 in the ILA group. Part III confirmed that venous superdrainage is less efficacious in reducing flap necrosis than arterial supercharging, in which the position of the additional artery was far more important than the diameter. ConclusionsThe extensive dilation of the venous component of choke vessels makes a more potent compensatory role for venous drainage after flap harvest, indicating arterial supercharging is better in augmenting flap viability than venous superdrainage.

Application of venous super drainage technique in free flaps transfer

Objective To investigate the effect of venous super drainage applying in free flaps. Methods From June, 2017 to December, 2018, 7 cases who had severe soft tissue injuries were treated with free flap. Cause of injury: 1 electric injuries, 2 tumor-related wounds, 1 deep burns, 2 mechanical trauma, and 1 necrotizing fasciitis. All patients were underwent free flap transplantation. There were 5 cases of anterolateral thigh artery perforator flap, 1 case of superficial circumflex iliac artery perforator flap, and 1 case of first dorsal metatarsal artery perforator flap. The application of venous super-drainage technology was carried out according to needs and specific conditions. Two sets of venous passages were prepared in both recipient and donor site to form a double set of venous reflux super-drainage mode. Blood supply, swelling, exudation, secondary exploration and survival rate of the flap were observed after operation, and regularly followed-up. Results All 7 flaps survived. Venous super drainage technique was applied in 7 cases. No arteriovenous crisis occurred after the operation. The flaps had good blood circulation, slight swelling, less exudation, rapid edema regression and no secondary surgical exploration. Followed-up for 2-18 (average 10.5) months, there was no infection recurred. Flaps survived well, and the donor sites healed well without sensory loss. The flexion and extension function of joint was normal. Conclusion The technique of venous super-drainage prepares 2 sets of venous systems for the free flap in the treatment of vascular pedicle in the free flap repair operation, which is conducive to reducing the venous crisis after flap surgery, reducing flap edema, reducing exudation, reducing secondary surgical exploration and improving the survival rate of the flap. Key words: Venous super drainage; Free flaps; Vascular crisis; Repair

Application of venous superdrainage technique based anterolateral thigh flap based on oblique branch for the soft tissue defect of proximal shank

Objective To investigate the application of venous superdrainage technique based anterolateral thigh flap based on oblique branch for the soft tissue defect of proximal shank. Methods Between October, 2012 and March, 2017, 11 cases of the soft tissue defect in proximal shank were treated. There were 8 males and 3 females with a mean age of 43 (range, 26-59) years. Causes of injury: 7 cases of traffic injury, 3 cases of bruise, 1 case of machine wound; The defect sizes ranged from 10 cm×5 cm to 13 cm×10 cm, with fracture or plate exposure. According to the size of the defect, the distally based anterolateral thigh flap was designed to repair the defect. The flap sizes ranged from 14 cm×6 cm to 16 cm×8 cm. The oblique branch and their accompanying vein with great saphenous vein was anastomosed to construct the venous superdrainage, and the donor site suture directly. Three cases followed-up by WeChat, and 8 cases by return visit. Results Distally based anterolateral thigh flaps were derived from oblique branches, and no arteriovenous crisis occurred postoperatively. Eleven flaps healed well after operation. There were no distal end blood supply disorder. Followed-up for 6-12 months, the flaps survived well. The texture was closed to the surrounding skin, and no ulcer exposed. There were no serious complications in donor site. And the thighs were linear scars. Conclusion The distally based anterolateral thigh flap based on oblique branch have a long vascular pedicle. The venous superdrainage technique can effectively avoid venous crisis, and improve the survival quality of the flap and the survival rate. Key words: Anterolateral thigh flap; Perforator flap; Oblique branch, lateral circumflex femoral artery; Shank; Superdrainage technique

A Preliminary Study of the Effects of Venous Drainage Position on Arterial Blood Supply and Venous Return within the Conjoined Flap.

Background:Conjoined flap viability is associated with arterial blood supply and venous return. This study aimed to assess the effects of venous drainage position on arterial blood supply and venous return within the conjoined flap.Methods:Fifty-four rats were divided randomly into three groups (n = 18 per group). In experimental group 2, only the right intercostal posterior artery and the left iliolumbar vein were maintained; meanwhile, only the right intercostal posterior artery and the left intercostal posterior vein were preserved in experimental group 1. The control group had only the right intercostal posterior artery and vein preserved. The distances between angiosomes were measured. At 7 days after surgery, flap survival was evaluated, lead oxide–gelatin flap angiography was performed, and average microvessel density was assessed by hematoxylin and eosin staining, and lactate levels were assessed.Results:The distance between angiosomes I and II was the shortest, whereas angiosomes I and III were most distant (p < 0.05). At 7 days after surgery, survival rates in experimental group 2 and experimental group 1 were both 100 percent, whereas 86.5 ± 1.6 percent of controls survived. Furthermore, angiogenesis was more obvious in experimental group 2 than in experimental group 1 and controls. Moreover, lactate levels were lower in experimental group 2 (7.47 ± 0.17 mM) and experimental group 1 (8.03 ± 0.31 mM) compared with control values (9.98 ± 0.37 mM; p < 0.05).Conclusion:Changes in position of venous drainage might cause continuous arterial high-pressure perfusion and venous superdrainage, which improves flap survival.

Effect of distal venous drainage on the survival of four-territory flaps with no pedicle vein: Results from a rat model

Venous super-drainage can improve flap survival not only because it prevents congestion, but also because it affects the dominant circulation in multi-territory thin skin flaps. We aimed to evaluate the survival of various flap areas and detect vascular changes in artery-based, four-territory skin flaps after different distal venous drainage procedures. 4 x 12 cm sized flaps were elevated based only on the deep circumflex iliac artery. Fifty rats were divided into five groups, as follows: group 1, flaps drained with the deep circumflex iliac vein; group 2, flaps drained with the ipsilateral superficial inferior epigastric vein; group 3, flaps drained with the contralateral superficial inferior epigastric vein; group 4, flaps drained with the contralateral deep circumflex iliac vein; and group 5, flaps super-drained with the contralateral deep circumflex iliac vein. On the fourth postoperative day, the survival of the flaps was assessed by measuring the necrotic and surviving areas, and vascular changes were evaluated angiographically. Compared to flaps with only arterial-based pedicles, most flaps with distant drainage showed significantly greater survival. The flap survival area percentages were 37.82 ± 5.01%, 49.23 ± 10.47%, 68.22 ± 9.24%, 83.90 ± 12.03%, and 89.17 ± 10.42% for groups 1, 2, 3, 4, and 5, respectively. Furthermore, distal vein drainage above the ventral midline resulted in significantly better flap survival. Super-drainage and drainage via the most distal vein resulted in similar flap survival. Distal vein drainage is effective for increasing survival in artery-based flaps.

Application of reverse anterolateral thigh flap with venous superdrainage

Objective To investigate the application effect of venous superdrainage to repair the wound around the knee joint with reverse anterolateral thigh flap. Methods From February, 2010 to August, 2015, 7 patients with wound around the knee joint were treated with reverse anterolateral thigh flap. The size of wound ranged from 15 cm × 6 cm to 20 cm × 10 cm..Which bone and joint ligament exposed to air..With outside pressure and venous superdrainage, it can effectively solve the problem of venous stagnation, anastomosing their veins accompanied with the lateral femoral circumflex artery descending branch with the veins in the neighborhood, when repaired the wound with reverse anterolateral thigh flap..The size of the flap ranged from 17 cm × 8 cm to 23 cm × 12 cm. The donor sites were sutured directly or covered with full-thickness skin graft. Results All the 7 flaps survived completely without vascular crisis and swelling. These flaps had abundant blood supply an good appearance, soft texture, normal skin color, no pigmentation. Conclusion With venous superdrainage, it can effectively solve the problem of venous stagnation of reverse anterolateral thigh flap, and improve the survival rate of flaps. Key words: Anterolateral thigh flap, reverse; External pressure; Superdrainage; Descending branch, lateral femoral circumflex artery; Wound repair

Hemodynamic Effect of Different Kinds of Venous Augmentation in a Pig Transmidline Flap Model of DIEP Flap

Venous augmentation enhances the viability of the deep inferior epigastric perforator (DIEP) flap. We compared the efficacy of three venous superdrainage procedures on survival area and hemodynamics of the DIEP flap model. In 24 castrated Yorkshire pigs, a true abdominal perforator-based flap was created based on four perforators arising from the deep superior epigastric vessels. Three remaining venous tracts were alternated to represent different venous augmentations of the DIEP flap. Analyzed were flap perfusion, venous blood pressure, and venous blood gas. In control animals, all three supplemental veins were ligated; the ipsilateral superficial superior epigastric vein (SSEV) was retained in the IS (ipsilateral SSZV augmented) group, the contralateral SSEV in the CS (contralateral SSZV augmented) group and the contralateral deep superior epigastric vein (DSEV) in the CD (contralateral DSZV augmented) group. The flap was then returned to its bed, and animals sacrificed on the seventh day postoperatively. DIEP flap survival was then recorded. All four intraoperative parameters showed improved perfusion of the distal flap area under distal venous augmentation. Efficacy was CDSEV > CSSEV > ISSEV > none. Skin islands of the CD and CS groups survived completely. In the IS and control groups, 96.33 ± 3.16% and 84.00 ± 7.55% of skin islands survived, respectively. Test groups were statistically significantly different from the control group but not from each other. Venous superdrainage effectively enhances DIEP flap survival. Benefit was relatively the same for all procedures. An additional venous route should be preserved with large or multiterritory flaps to improve venous congestion.

Vascular pressure monitorization for necessity of vascular augmentation in a rat extended abdominal perforator flap model

In case blood perfusion compromises, vascular enhancement with arterial supercharge or venous superdrainage can increase viability of the flap. In this study, vascular pressure monitorization was used in a rat extended abdominal perforator flap model to reveal intraoperative vascular compromise and the need for vascular augmentation. A rat abdominal perforator flap was designed, which was based on the right second cranial perforator of epigastric artery. Vascular pressures of the flap were monitored continuously for 60 min, by catheters placed in the right superficial inferior epigastric artery and vein. Forty rats were divided into four experimental groups, as follows: group 1 (n = 10, no vascular augmentation), group II (n = 10, arterial supercharge), group III (n = 10, venous superdrainage), and group IV (n = 10, arterial and venous augmentation). Arterial supercharge and/or venous superdrainage were performed by using the left superficial inferior epigastric artery and vein. After the rats were sacrificed on the 7th day, total flap area and necrotic regions were evaluated. Mean arterial blood pressure was found significantly lower (P < 0.05) and mean venous blood pressure was measured significantly higher (P < 0.05) in group I than the groups II, III, and IV. Flap survival area was also larger in the groups II, III, and IV than the group I (P < 0.05). The results of this experimental study demonstrate that arterial insufficiency and venous congestion are almost always present in the rat extended abdominal perforator flap model, similar to deep inferior epigastric perforator flap. When such an extended perforator flap is used, arterial and venous pressure monitorization may be considered as a tool to support intraoperative clinical findings to reveal the need of vascular augmentation and ascertain flap viability.

Effect of vascular augmentation on the haemodynamics and survival area in a rat abdominal perforator flap model

A major drawback of the DIEP flap is the compromised venous drainage in the distal area, which is the rationale behind the creation of additional venous anastomoses for better flap survival. Although venous congestion is defined as an increase in the venous pressure, the effect of vascular augmentation on the venous pressure has not been elucidated. We investigated the effects of arterial supercharge and venous superdrainage on the venous pressure and the flap survival area in a rat abdominal perforator flap model. An abdominal perforator flap was raised in each of 30 Wistar rats, with the contralateral superficial inferior epigastric artery (SIEA) and vein (SIEV) isolated for pressure measurements. The changes in the SIEV pressure were recorded while proximal sites of these vessels were opened and closed. Thereafter, the animals were divided into three groups: a control group (n=10, both the SIEA and SIEV were ligated), an enhanced arterial inflow (EAI) group (n=10, the SIEA was left intact) and a supplemental venous outflow (SVO) group (n=10, the SIEV was left intact). The flap survival area was determined 7 days after surgery. The SIEV pressure without vascular augmentation was only 13.2+/-5.9 mm Hg. Compared with the control group, the flap survival area was significantly larger in the EAI group, but not in the SVO group. An extremely high venous pressure was noted when the SIEA was opened and the SIEV was occluded, but there was great variation among the individual animals (range: 21.2-79.6 mm Hg). The necrotic area in the EAI group correlated well with the SIEV pressure (r=0.861). These findings indicate that the major factor contributing to distal necrosis in this rat perforator flap model is arterial insufficiency rather than venous congestion. The results suggest that, as long as the arterial inflow is secure, the venous pressure is a reliable parameter for deciding the necessity of venous superdrainage.