Flap Length Research Articles

Modified Internal Pudendal Artery Perforator Flap Interposition for Rectovaginal Fistula.

Rectovaginal fistula (RVF) is a challenging condition associated with recurrences and significant functional impairment. The internal pudendal artery perforator (IPAP) flap has become a viable option for reconstructing the vagina and perineal regions. This study aims to introduce a modified technique of IPAP flap interposition and evaluate its postoperative outcomes in the treatment of low RVF. Sixteen patients with RVF who underwent modified IPAP flap interposition between 2016 and 2021 were retrospectively enrolled. Recurrence rate, the satisfaction of vulvar appearance (Visual Analog Scale), and quality of sexual life (Female Sexual Function Index score) were followed up and analyzed. All patients presented with low fistula with a mean diameter of 8.3 mm. The mean width and length of the IPAP flaps were 3.8 and 6.2 cm, respectively. The mean follow-up period was 14.1 months. All patients achieved successful healing without recurrence. High satisfaction was reported for the cosmetic effect of the vulva with a mean Visual Analog Scale score of 8.4. The proportion of female sexual disorder exhibited a statistically significant reduction, decreasing from 100% preoperatively to 38% after surgery ( P < 0.05). The modified IPAP flap interposition is a reliable and safe option for repairing low RVF, with high success rates and minimal donor site morbidity. Moreover, this procedure provides a suitable volume flap and preserves the vaginal physiological environment, which benefits postoperative sexual function.

Danger Zone for Paramedian Forehead Flap Elevation: Maximizing Flap Length and Viability

The supratrochlear artery (STA) demonstrates anatomical variability that impacts facial reconstruction with a paramedian forehead flap. STA branching patterns and the distance to the midline have been reported, but the STA pedicle has not been characterized. Our aim was to triangulate the STA pedicle relative to known anatomical landmarks and identify a danger zone to aid surgeons in creating viable tissue flaps. The upper facial region was dissected bilaterally on 38 cadaveric donors. Measurements from the supraorbital neurovascular bundle, orbital rim, and medial canthus to the STA pedicle were collected. Data were tallied and statistically analyzed. Measurement means, range, and standard deviations were calculated; no significant differences were found in the laterality of the measurements (p &gt; 0.05). Statistically significant, sex-based differences were identified for all measurements collected among male and female donors. This study characterizes a surgical danger zone for the STA pedicle specific to a paramedian forehead flap and identifies important differences within this danger zone among male versus female donors that surgeons should consider to prevent pedicle violation and enhance surgical success while maximizing flap length and mobility.

EFFECT OF FLEXIBLE FLAP LENGTH ON FLOW GENERATION BY AN AIRFOIL PITCHING IN QUIESCENT FLUID

We experimentally investigate the effect of the length of a chordwise flexible surface (flap) attached to the trailing edge of a symmetric rigid airfoil purely pitching in quiescent fluid on flow, and thus thrust generation. We aim to identify the optimum length of the flexible appendage necessary for coherent, orderly jet generation in a situation relating to hovering. To this end, we consider a flexible flap of a 50 &amp;mu;m thick polyethylene sheet. We systematically vary the length of the flexible flap (&lt;i&gt;c&lt;sub&gt;f&lt;/sub&gt;&lt;/i&gt;) over a wide range, from &lt;i&gt;c&lt;sub&gt;f&lt;/sub&gt;&lt;/i&gt; &amp;#61; 0.5 c to 4 c, where c is a rigid foil chord. Moreover, we explore the effect of pitching amplitude and frequency for each flap length. Based on length, the flaps are categorized as short (&lt;i&gt;c&lt;sub&gt;f&lt;/sub&gt;&lt;/i&gt; &amp;le; 1), moderate length (1 &amp;#60; &lt;i&gt;c&lt;sub&gt;f&lt;/sub&gt;&lt;/i&gt; &amp;le; 2), and long (&lt;i&gt;c&lt;sub&gt;f&lt;/sub&gt;&lt;/i&gt; &amp;#62; 2) flaps. Detailed particle visualization study reveals that flap length has the predominant effect onflow generation. We find that for small amplitude-frequency pitching, flaps with moderate length generate narrow and coherent jets, while short and long flaps generate spread out and deflected jets. For moderate amplitude-frequency pitching, flexible flaps of all lengths, except the short flaps, generate coherent and aligned jet. However, for large amplitude-frequency pitching, only a few long flaps produce a narrow jet and thrust along the centerline. Results suggest that optimum flap length is a strong function of pitching kinematics. Interestingly, we also find that more than one optimal flap length exists for moderate and large pitching parameters which generate the orderly jet with small/minimum width.

Enhancing the Performance of an Oscillating Wing Energy Harvester Using a Leading-Edge Flap

In this study, we investigated the power generation capability of an oscillating wing energy harvester featuring an actively controlled flap positioned at the wing’s leading edge. The findings revealed that attaching a leading-edge flap reduces fluid flow separation below the wing’s lower surface at the leading edge, resulting in smoother flow and increased velocity near the hinge region. The leading-edge flap increases the pressure difference across the wing’s surface, thereby enhancing the overall performance. In addition, the introduction of the leading-edge flap effectively elongates the wing’s effective projected length in the heaving direction, leading to increased thrust. We examined flap lengths ranging from 10% to 50% of the chord length, with the maximum pitch angles of the wing and flap varying from 75° to 105° and 30° to 55°, respectively. The optimal power generation was achieved using a flap length of 40% of the chord length, combined with maximum wing and flap pitch angles of 95° and 45°, respectively. These conditions yielded a 29.9% overall power output increase and a 20.2% efficiency improvement compared to the case without the leading-edge flap.

Improvement of vertical axis wind turbine performance by using the optimized adaptive flap by the Taguchi method

ABSTRACT In light of the growing use of Vertical Axis Wind Turbines (VAWTs) in urban settings, research is increasingly focusing on passive control methods to enhance VAWT efficiency. This study aims to refine VAWT performance by optimizing an advanced turbine design equipped with an adaptive flap on the blade, focus on the power coefficient (CP). Using the Taguchi method, the optimization incorporated five control factors: flap position (ld), flap length (lf), flap angle (θ), flap tip length (lt), and angle of the flap tip length (αtip). The study employed an L16 (54) orthogonal array design. At a 2.62 tip speed ratio (TSR), all models underwent computational fluid dynamics (CFD) simulation. The influence of each factor was assessed using the ANOVA (Analysis of variance), and CP predictions were made based on these factors through Regression Analysis (RA). The results revealed optimal configurations of ld = 0.65c, lf = 0.15c, θ = 70°, lt = 0.06c, and αtip = 8, leading to a CP 74.01% greater than a conventional VAWT. ANOVA ranked factor contributions as: ld > lt > θ > lf > αtip, with ld contributing 39.58% and αtip only 1.34%. Predictions from the RA aligned well with the numerical findings. In conclusion, the adaptive flap design enhances performance by expanding the wake and amplifying the vortices behind the turbine blade.

Effects of Gurney Flaps on the Performance of a Horizontal Axis Ocean Current Turbine

Gurney flaps can enhance the hydrodynamic efficiency of airfoils, and they are currently used in several applications, including racing cars and wind turbines. However, there is a lack of studies in the literature on the application of Gurney flaps on the Horizontal Axis Ocean Current Turbine (HAOCT). The influence of Gurney flaps on the hydrodynamic efficiency of the HAOCT is evaluated through numerical analysis. The effect of the Gurney flaps on the turbine is evaluated after the validation of the utilized numerical method is completed using the wind tunnel experimental data of the two-dimensional NACA 63415 airfoil and the water tunnel experimental data of the NACA 638xx series rotor on the clean blade. By calculating the velocity and pressure fields of the 2D airfoil by CFD, it was possible to analyze the lift improvement with the addition of the Gurney flaps by evaluating the pressure difference between the pressure surface and the negative pressure surface, and the drag improvement was due to the Gurney flaps obstructing the chordal flow of the fluid in the wake. For the 2D NACA-63415 airfoil, the drag coefficient increases with the increase in the head angle, while the lift coefficient increases and then decreases. The flap height divided by the local chord length of the Gurney flaps is 0.01, and the lift-to-drag ratio is the highest when the head angle is 4°. For the NACA-638xx turbine, the addition of Gurney flaps significantly increases the axial thrust coefficient. At lower tip speed ratios, the effect of the Gurney flaps on the rotor’s power coefficient is limited, with the greatest increase in the power coefficient at a tip speed ratio of 6 and a decrease in the power coefficient increase as the tip speed ratio increases. Increasing the height of the Gurney flaps can increase the peak power coefficient, but the power performance decreases at high tip speed ratios. The Gurney flaps distributed at the root of the rotor have less effect on the power performance. A 0.4 local radius spread of the Gurney flaps increases the peak turbine power coefficient by only 0.34%, while full-length Gurney flaps can increase the peaked blade power coefficient by 10.68%, indicating that Gurney flaps can be used to design a new HAOCT.

Anatomic study and clinical application of iliac crest chimeric tissue flap

To conduct anatomical study on the iliac crest chimeric tissue flap and summarize its effectiveness of clinical application in repairing limb wounds. Latex perfusion and anatomical study were performed on 6 fresh adult cadaver specimens with 12 sides, to observe the initial location, distribution, quantity, and direction of the common circumflexa iliac artery, the deep circumflexa iliac artery, and the superficial circumflexa iliac artery, and to measure their initial external diameter. Between December 2020 and September 2022, the iliac crest chimeric tissue flap repair was performed on 5 patients with soft tissue of limbs and bone defects. There were 3 males and 2 females, with an average age of 46 years (range, 23-60 years). Among them, there were 3 cases of radii and skin soft tissue defects and 2 cases of tibia and skin soft tissue defects. The length of bone defects was 4-8 cm and the area of skin soft tissue defects ranged from 9 cm×5 cm to 15 cm×6 cm. The length of the iliac flap was 4-8 cm and the area of skin flap ranged from 12.0 cm×5.5 cm to 16.0 cm×8.0 cm. The donor sites were directly sutured. Anatomical studies showed that there were 10 common circumflex iliac arteries in 5 specimens, which originated from the lateral or posterolateral side of the transition between the external iliac artery and the femoral artery, with a length of 1.2-1.6 cm and an initial external diameter of 0.8-1.4 mm. In 1 specimen without common circumflexa iliac artery, the superficial and deep circumflex iliac arteries originated from the external iliac artery and the femoral artery, respectively, while the rest originated from the common circumflex iliac artery. The length of superficial circumflex iliac artery was 4.6-6.7 cm, and the initial external diameter was 0.4-0.8 mm. There were 3-6 perforator vessels along the way. The length of deep circumflex iliac artery was 7.8-9.2 cm, and the initial external diameter was 0.5-0.7 mm. There were 3-5 muscular branches, 4-6 periosteal branches, and 2-3 musculocutaneous branches along the way. Based on the anatomical observation results, all iliac crest chimeric tissue flaps were successfully resected and survived after operation. The wounds at recipient and donor sites healed by first intention. All patients were followed up 8-24 months, with an average of 12 months. The tissue flap has good appearance and soft texture. X-ray film reexamination showed that all the osteotomy healed, and no obvious bone resorption was observed during follow-up. The common circumflex iliac artery, deep circumflex iliac artery, and superficial circumflex iliac artery were anatomically constant, and it was safe and reliable to use iliac crest chimeric tissue flap in repairing the soft tissue and bone defects of limbs.

Cadaveric and Computed Tomography Analysis of the Anterior Ethmoidal Artery Flap.

The anterior ethmoidal artery (AEA) flap has been successful in repairing anterior nasal septal perforations and has been presumed to be axially based on AEA branches coursing through or around the cribriform plate (CP). However, limited evidence supports the flap's axial supply. The purposes of this cadaveric and computed tomography (CT) study were to assess the arterial anatomy from the CP to the septum, and to determine AEA flap length to predict ideal flap base width. Ten fresh latex-injected cadavers were utilized for endoscopic dissection to identify arteries traversing the CPs on each side. First, arterial trajectories along the dorsal septum were recorded. Measurements were then made bilaterally along the septum from the middle turbinate (MT) axilla to the nasal branch of the AEA (NBAEA) traversing the CP. Additionally, 100 sinus CTs were reviewed to measure AEA flap lengths bilaterally. From 10 cadavers, 20 sides were utilized for measurements. In all cadavers, the AEA septal branches coursed diagonally or horizontally along the dorsal septum, and never directly vertically. The mean distance from the MT axilla to the NBAEA was 1.24 ± 1.93 cm (range = 1-1.5 cm). Based on CTs, the mean AEA flap length was 6.40 ± 0.60 cm. Based on the non-vertical courses of AEA septal branches, the AEA flap is more likely a random transposition flap than an axial flap. Average AEA flap length ranged from 6.0 to 7.0 cm. Assuming 3:1 length:width ratios, AEA flap base widths should be about 2.0-2.3 cm. NA Laryngoscope, 134:2100-2104, 2024.

Influence of trailing edge flap length and deflection angle on the performance of the multiphase pump

At medium to high gas content rates, the gas-liquid separation phenomenon and the stagnation behaviors of the gas masses occurring in the impeller channels are essential factors affecting the hydraulic performance of multiphase pumps. This paper designs a split trailing edge flap suitable for the multiphase pump to improve the hydraulic performance in the impeller by varying the flap deflection angle and length. The model’s reliability was assessed by comparing the experimental outcome with the external characteristics of the experimental data. Based on the Eulerian-Eulerian multiphase model and the SST k‐ω turbulence model, the effects of different flap lengths on external characteristics, the turbulent kinetic energy and pressure distribution are analyzed. The study results show that when the length of the separated trailing edge flap is 0.25 l0 and the deflection angle is 5°, the transporting efficiency of the multiphase pump is the highest at IGVF=50% with an efficiency increase of 3.40% compared to the original model. Its optimal flap length scheme effectively reduces the radial pressure gradient and the inverse pressure gradient in the impeller channel, which suppresses the gas blockage phenomenon to a certain extent.

Digital skin defect management: Hand and wrist volar flap solutions

BackgroundSelecting the optimal flap for managing digit skin defects is challenging, particularly for inexperienced surgeons, given the numerous reconstructive options and insufficient evidence supporting one flap type's superiority over another. This retrospective study introduces four efficacious hand flaps to address volar skin defects and transverse and oblique cuts, examines the optimal flap advancement distance, and discusses effective management. MethodsPatients with digit skin defects who underwent flap surgery between 2009 and 2022 were included. Fifty-four patients treated with oblique triangular, volar VY advancement (unilateral and bilateral pedicled volar VY advancement flaps for fingers and thumbs, respectively), reverse homodigital island, and radial artery superficial palmar branch flaps were included. We evaluated the flap advancement distance, flap length, range of motion, complications, and Semmes–Weinstein monofilament test and Disabilities of the Arm, Shoulder, and Hand questionnaire results. ResultsThe median flap advancement distances for triangular oblique (19 patients), unilateral (11 patients), and bilateral pedicled (5 patients) volar VY advancement flaps were 1.3, 1.8, and 2.0 cm, respectively. The flap lengths for the reverse digital island (8 patients) and radial artery superficial palmar branch (11 patients) flaps were 2.4 and 5.0 cm, respectively. Five, three, and one cases of proximal interphalangeal flexion contractures of ≥ -20° were observed in the VY advancement, reverse digital island, and radial artery superficial palmar branch flaps, respectively. One unilateral VY advancement flap case caused severe numbness and neuroma. All complication cases featured >15 and > 20 mm defect lengths on the fingers and thumb, respectively. ConclusionsTo minimize sensory disruption and contractures, we recommend oblique triangular and unilateral pedicle volar VY advancement flaps for finger skin defects up to 12 mm and defects sized 12–15 mm, respectively. Advancement flaps are unsuitable for >15 and > 20–25 mm defects on the fingers and thumb, respectively.

Flow Control in Multiphase Pumps Based on Separated Trailing Edge Flap

In developing and transporting significant oil fields in deep-sea environments, multiphase pumps are considered crucial energy conversion equipment. Ensuring their safe, efficient, and stable operation is currently a primary focus of research. The intermittent aggregation of the gas phase at the trailing edge flap of the impeller blades in multiphase pumps can lead to periodic and significant fluctuations in flow rate and outlet pressure, posing a threat to the overall operational safety of the pump system. Based on aerodynamic principles, this paper presents the design of a separate trailing edge flap for the impeller blades. The inner nodal method is applied to determine the design scheme of the trailing edge flap for the multiphase pump. A numerical approach is employed to analyze the impact of the flap deflection angle on the internal flow characteristics to provide theoretical guidance for the structural optimization of multiphase pumps. The results indicate that the influence of the deflection angle on the pump efficiency is complex and affected by a critical angle value. When the deflection angle is below the critical value, the trailing edge flap can effectively reduce the formation of energy dissipation vortices and radial pressure gradients within the impeller channel, enabling a significant improvement in the gas-phase aggregation phenomenon caused by gas–liquid separation. However, additional energy losses occur at the connection between the trailing edge flap and the main blade body for deflection angles exceeding the critical value. When the trailing edge flap length is 0.25 l and the deflection angle is 5°, the efficiency is improved by 3.4% compared to the original model. Consequently, the pressurization capacity of the pump is compromised. In the design and application of trailing edge flaps, a careful balance between various factors is required to ensure both the stability and high efficiency of the pump system.

Using Laser-Assisted Indocyanine Green Angiography to Assess Nipple-Areolar Complex Survival During Reduction Mammoplasty.

In reduction mammoplasty, preserving an appropriate skin flap is crucial to achieve a favorable postoperative appearance and prevent blood supply disorders in the nipple-areolar complex (NAC). Previous studies have indicated that a thinner or narrower flap is more favorable for breast shaping, but also increases the risk of blood supply disorders. Accessing the blood perfusion of the NAC and determining the critical threshold for NAC viability are essential aspects of reduction mammoplasty. The aim of this study was to utilize indocyanine green (ICG) angiography to assess NAC perfusion during reduction mammoplasty. It also sought to identify critical thresholds of various indicators affecting NAC survival and provide guidance for skin flap trimming. Thirty-eight patients who underwent reduction mammoplasty were included. Each patient received ICG angiography before and after skin flap trimming. Data on NAC perfusion, skin flap length, width, thickness, and other relevant indicators were collected. Among the patients, 5 experienced NAC blood supply disorders. Multiple linear regression analysis demonstrated that the NAC blood supply had a significant correlation with the tissue thickness at the pedicle base (P < .001) and with the length-to-width ratio across the nipple (P < .05). To optimize NAC survival and achieve favorable breast shaping, cutoff points for the thickness at the pedicle base and the length-to-width ratio across the nipple of 1.15 cm and 1.71, respectively, were established. ICG angiography provides an effective means to assess NAC blood supply and postoperative survival. The cutoff points established in this study help to predict the survival of the NAC and guide flap trimming.

Flow over a circular cylinder with a flexible splitter plate

In the present work, we study the flow field around, and forces acting on, a circular cylinder with an attached flexible splitter plate/flap. Two cases of flap length ( $L/D$ ), namely, $L/D = 5$ and $L/D = 2$ have been investigated focusing on the effect of variations in flap flexural rigidity, $EI$ . We find that for a range of $EI$ and Reynolds numbers $Re = UD/\nu$ , a non-dimensional bending stiffness $K^{\ast }=EI/((1/2)\rho U^2 L^3)$ collapses flap motion and forces on the system well, as long as $Re&gt;5000$ . In the $L/D = 5$ flap case, two periodic flap deformation regimes in the form of travelling waves are identified (modes I and II), with mode I occurring at $K^{\ast } \approx 1.5\times 10^{-3}$ and mode II at lower $K^{\ast }$ values ( $K^{\ast }&lt;3\times 10^{-5}$ ). In the $L/D = 2$ flap case, we find a richer set of flapping modes (modes A, B, C and D) that are differentiated by their flapping characteristics (symmetric/asymmetric and amplitude). Force measurements show that the largest drag reduction occurs in mode I ( $L/D = 5$ ) and mode C ( $L/D = 2$ ), which also correspond to the lowest lift and wake fluctuations, with the mode C wake fluctuations being lower than even the rigid splitter plate case. In contrast, the highest fluctuating lift, in both $L/D$ cases, occurs at higher $K^{\ast }$ , when the wake frequency is close to the first structural bending mode frequency of the flap. The observed rich range of flap/splitter plate dynamics could be useful for applications such as drag reduction, vibration suppression, reduction of wake fluctuations and energy harvesting.

Swept-Source Anterior Segment Optical Coherence Tomography Imaging and Quantification of Bleb Parameters in Glaucoma Filtration Surgery.

This paper describes a technique for using swept-source anterior segment optical coherence tomography (AS-OCT) to visualize internal bleb microstructure and objectively quantify dimensions of the scleral flap and trabeculo-Descemet window (TDW) in non-penetrating glaucoma filtration surgery (GFS). This was a cross-sectional study of 107 filtering blebs of 67 patients who had undergone deep sclerectomy surgery at least 12 months prior. The mean post-operative follow-up duration was 6.5 years +/- 4.1 [standard deviation (SD)]. The maximal bleb height was significantly greater in the complete success (CS) blebs compared to the qualified success (QS) and failed (F) blebs (1.48 vs. 1.17 vs. 1.10 mm in CS vs. QS vs. F, one-way ANOVA, p < 0.0001). In a subcohort of deep sclerectomy blebs augmented by intraoperative Mitomycin-C, the trabeculo-Descemet window was significantly longer in the complete success compared to the qualified success group (613.7 vs. 378.1 vs. 450.8 µm in CS vs. QS vs. F, p = 0.004). The scleral flap length, thickness, and width were otherwise similar across the three outcome groups. The quantification of surgical parameters that influence aqueous outflow in non-penetrating GFS can help surgeons better understand the influence of these structures on aqueous outflow and improve surgical outcomes.

The Role of Location, Length, and Thickness of the Intimal Flap in the Propagation of Stanford Type B Aortic Dissection Based on Ex Vivo Porcine Aorta Models.

To explore the role of location, length, and thickness of the intimal flap in the propagation of Stanford type B aortic dissection (TBAD) based on ex vivo porcine aorta models based on ex vivo porcine aorta models. The porcine aortas were harvested and randomly divided into 6 groups to create various TBAD aortic models. We constructed intimal flaps for different locations (group A [entry tear on outer curvature] and group B [entry tear on inner curvature]), lengths (group C [long] and group D [short]), and thicknesses (group E [thick] and group F [thin]). For the ex vivo perfusion experiments conducted on model aortas, an experimental circulation loop (ECL) was employed. The pressure in false lumen (FL) was constantly monitored. A comparison was made between the morphological data collected before and after the experiment to quantify the changes in the FL after the experiment. Compared the results with group B, the mean peak pressures of the FL in group A were lower (106.87±15.55 vs. 124.01±22.75 mm Hg, p=0.028). The mean axial propagation length in group A was shown to be shorter than that of group B (88.14±33.38 vs. 197.43±41.65 mm, p<0.001). The mean peak pressure was higher in group C than in group D (144.04±19.37 vs. 92.51±26.70 mm Hg, p<0.001). The mean peak pressure of group E was higher than that of group F (160.83±32.83 vs. 109.33±15.62 mm Hg, p<0.001), as was the mean axial propagation length of group E (143.11±39.73 vs. 100.45±35.44 mm, p=0.021). According to the results of multivariable linear regression, axial propagation length=45.873-0.703×length of initial FL+0.863× peak pressure (p<0.001). There was a relationship between FL propagation and the location, length, and thickness of the intimal flap. The axial propagation length was related to the length of the intimal flap and the peak pressure of propagation. It may be helpful to evaluate the risk of propagation in patients with TBAD. This study found that the locations, lengths, and thickness of the intimal flap significantly contributed to propagation pressure of FL. Using dissection flap characteristics, a physician can predict FL development in a patient and formulate a treatment plan.The purpose was to investigate the relationship between the dissection flap characteristics (location, length, and thickness) and the propagation of the FL, which is not clear at present. This study employed porcine models to create an experimental circulation loop. The perfusion experiment was conducted using a FL without distal re-entry and a non-pulsating flow.

750 Fluid Therapy Regimen and Free Flap Failure in Post-Resection Reconstruction for Head and Neck Cancer: A Systematic Review

Abstract Background The importance of developing standardized approaches away from wide-range fluid administration regimens has been growing. The aim of the following study is to evaluate the current evidence with regards to fluid therapy regimens and their effects on flap complications in free-flap reconstruction of head and neck cancer. Method A systematic database search was conducted of original articles that included fluid therapy regimens in free-flap reconstruction of head and neck cancer in EMBASE, MEDLINE, Cochrane database and Google Scholar, from inception to January 2021. Our main outcomes were presence of a flap complication or failure and total length of hospital stay. Results We identified 327 studies from our search, of which 11 studies met the inclusion criteria, comprising a total of 1,133 patients. Five studies showed that greater perioperative fluid volume was associated with higher rates of flap complication, with one drawing a cut-off at 5.5 L to predict any flap complication and 7 L to predict a major complication that required re-operation. Three studies assessed goal directed fluid therapy, with two showing significantly reduced intraoperative fluid volume within this group, but no significant difference in flap outcomes. Two studies comparing crystalloid and colloid fluids concluded that there was no significant difference in outcomes when using either. Conclusions Excessive fluid administration negatively impacts surgical outcomes. Goal directed therapy presents insufficient evidence as a method for reducing flap complications and length of hospital stay. The clinical benefit of colloid fluid intra-operatively over crystalloids have not been unanimously demonstrated in this review.

Analysis of Factors Affecting Good Neovascularization After Indirect Bypass Surgery: A Two-center Retrospective Study

The purpose of this study was to analyze factors affecting good neovascularization after indirect bypass surgery. From August 2000 to July 2020, postoperative image results and medical records of 132 patients (159 hemispheres) who underwent EDAS of indirect bypass surgery at two institutions were reviewed retrospectively. Based on DSA results, angiogenesis after indirect bypass was divided into "good" or "poor" according to the Matsushima criteria. STA flap length affecting GPN were analyzed in the entire group (n= 159) and a MMD group (n= 134). In the entire group, GPN after EDAS was observed in 94 (59.1%) hemispheres. Age, MMD, hypertension, and bone flap size were identified as significant factors in univariate analysis. Also, in the MMD group, 86 (64.2%) hemispheres showed GPN. Hypertension and bone flap size were significant factors in both univariate and multivariate analyses. Cutoff values of bone flap size and GPN were 47.91cm2 in the entire group and the MMD group. In all patients who received EDAS, good postoperative neovascularization was significant in those with a young age, MMD, without hypertension, and large bone flap size. No hypertension and large bone flap size were meaningful factors in the MMD group. AUROC showed that an appropriate bone flap size was 47.91cm2. However, a further controlled prospective study is needed.

A study on stabilizing mechanism of flap countermeasures mitigating VIV of a box girder bridge section

As bridge spans stretch, the structure becomes more flexible and susceptible to dynamic wind effects causing harmful wind-induced vibration. The biggest issue with the design of long-span bridges is the possibility of vibration caused by vortices. This study examines the mechanism of the decrease in the amplitude of vortex-induced vibration for the box girder using a flap countermeasure. Aerodynamic countermeasures such as a flap have successfully increased bridge deck aerodynamic stability. However, their stabilizing mechanism has yet to be fully understood. Based on the proposed approach, a wind tunnel experiment and a CFD technique are used to investigate the aerodynamic instability of the bridge girder in the presence of aerodynamic countermeasures. The flow fields surrounding the bridge deck, both with and without the flap, are examined, and the experiment outcomes are compared. Flow imagery is utilized to explain and understand the modified flow properties surrounding the bridge girder in the presence of aerodynamic countermeasures that minimize vibration amplitude. Indeed, installing flaps on a girder leads to increased turbulence over the surface and at the leeward side, which disrupts vortex formation and decreases lift forces on the structure. In addition, the results revealed that the efficiency of the flap is related to the installed location of the flap and the flap length. This research provides a reliable framework for designing the flap countermeasure and significantly improves the aerodynamic stability of a deck-flap system.

Pedicled thoracoacromial artery compound flaps for circumferential hypopharyngeal reconstruction.

Total laryngeal and hypopharyngeal resection remained to be the mainly treatment option for advanced hypopharyngeal cancer, which resulted in complicated reconstructive challenge for circumferential hypopharyngeal defect. The pedicled thoracoacromial artery compound flaps included Thoracoacromial artery perforator (TAAP) flap and pectoralis major myocutaneous (PMMC) flap. This study is to evaluate the clinical application of the pedicled thoracoacromial artery compound flaps for circumferential hypopharyngeal reconstruction. From May 2021 to April 2022, four hypopharyngeal cancer patients with circumferential hypopharyngeal defects were reconstructed by the pedicled thoracoacromial artery compound flaps. All patients were males. Patient age ranged from 35 to 62years (average, 50years). The Shoulder function were evaluated by SPADI. The average follow-up was 10.25months (range from 4 to 18months). All of the pedicled thoracoacromial artery compound flaps in our study survived. The defect length between tongue base and cervical esophagus ranged from 8 to 10cm after total laryngeal and hypopharyngeal resection. The TAAP flap size ranged from 6 × 7cm to 7 × 10cm, and the PMMC flap size ranged from 6 × 7cm to 9 × 12cm. The pedicle length of TAAP and PMMC flaps varied, respectively, from 5 to 8cm (mean 6.5cm) and 7cm to 11cm (mean 8.75cm). The mean time of TAAP and PMMC flaps harvest was, respectively, 82min and 39min. All patients were able to resume soft diet in the fourth week of postoperation, but one patient was operated by gastrostomy in the second month of postoperation because of pharyngeal cavity stenosis, and the patient successfully resumed oral soft diet by endoscopic balloon dilation after postoperation radiotherapy. All patients have resumed oral feeding at last. There were mild dysfunction for our patients according to SPADI during the mid-long follow-up. The pedicled thoracoacromial artery compound flaps have stable blood supply and provide adequate muscle coverage for greater protection during radiotherapy, and the microsurgical skills have no requirement. Therefore, the compound flaps provide a good choice for the reconstruction of circumferential hypopharyngeal defect, especially in the aged or patients with comorbidities who are not able to tolerate prolonged surgery.

Medial Femoral Condyle Free Flap for Persistent Osseous Nonunion of the First Metatarsophalangeal Joint: A Preliminary Report of a New Surgical Indication for the Medial Femoral Condyle Free Flap.

Recalcitrant or persistent nonunions of the metatarsophalangeal (MTP) joint occur following failed MTP surgery for MTP fusion, failed MTP prosthesis, for hallux rigidus or due to infection and erosion. A deficient soft tissue envelope and compromised vascular supply of tissues in this region compound further attempts to salvage the great toe and preserve function. The medial femoral condyle (MFC) free flap provides vascularized corticocancellous bone and periosteum and has been successfully used for a variety of complex hindfoot and ankle pathologies. We present an additional indication with a small cohort study demonstrating its use in persistent nonunions of the first MTP joint. A retrospective review was completed of all MFC flaps used for revision of failed first MTP joint fusion from January 2019 to November 2022. Demographic information, comorbidities, as well as clinical and radiologic follow-up was obtained from the patient charts. Three patients were included with MTP nonunion and an average of 7.5 (range, 5-11) failed prior surgeries. Mean age at index surgery was 50 (range, 46-57) years. An osseous union was achieved in all patients after 82 (range, 75-88) days. Hardware removal was possible after 81 (range, 55-98) days. Mean follow-up was 17 (range, 5-31) months. We note a 100% flap success rate without returns to the operating room. The lengths of the bone flaps were 2 to 4 cm, the volumes were 8 to 12 cm3. Fixation was performed with 1 intramedullary K-wire. The recipient vessel in all patients was the dorsalis pedis artery or a tributary thereof. All arterial anastomoses were performed under the operating microscope. The MFC free flap is a reasonable option for salvage of complex recalcitrant or persistent nonunions of the first MTP joint. More prospective long-term studies with functional outcomes are necessary to confirm these findings. Level IV, retrospective case series.