Flap Length Research Articles

Clinical effects of partially de-epithelized local flaps in repairing tubercular chest wall defects

Objective: To explore the clinical effects of partially de-epithelized local flaps in repairing tubercular chest wall defects. Methods: A retrospective observational study was conducted. From April 2010 to February 2021, twelve patients who met the inclusion criteria were admitted to the Department of Burns and Plastic Surgery of the Eighth Medical Center of PLA General Hospital, including 9 males and 3 females with age of (42±18) years. The sizes of tubercular chest wall defects of patients were ranged from 4 cm×3 cm×2 cm to 16 cm×8 cm×5 cm, which were all repaired with partial de-epithelized local flaps. The widths of flaps were equal to the widths of the defects, and the lengths of flaps were 2 cm longer than those of the defects. In one patient, the local flap was too large to close the donor site directly by suturing, so an autologous back free medium thickness skin graft was used for repair. In other patients, the collection areas of local flaps were small, and the donor areas of flaps were directly closed. The duration of operation, intraoperative bleeding, and postoperative drainage volume and indwelling time of drainage tube were observed and recorded. In two weeks after operation, the survival, color, and texture of flaps, the presence of subcutaneous hydrops and skin ulcer, and donor site healing including wound disruption, local infection, hematoma were observed. Chest X-ray, CT scan, or nuclear magnetic resonance imaging was performed in one month after operation to check whether new local hydrops and bone destruction occurred in the chest wall defects and the concomitant tuberculose focus of patients. All patients were followed up for more than 6 months to record whether the surgical incisions of the chest wall defects of the patients were complicated by hypertrophic scar, redness, swelling, and sinus. Results: In surgery, the patient had (104±18) min of operation duration, (119±53) mL of intraoperative bleeding, (134±49) mL of cumulative drainage of drainage tube, and (5.3±1.7) days of drainage tube indwelling time. In two weeks after operation, all the grafted local flaps survived, and the color and texture of flaps were similar to the surrounding normal skin. One patient had fluid leakage from the incision of chest wall defect area with the incision partially dehisced, which healed well after a phase Ⅱ operation; no wound infection, subcutaneous hydrops, or wound rupture occurred in other patients. The incisions of donor sites in all the patients healed well and no wound disruption, local infection, or hematoma occurred. One month after operation, no new bone destruction was observed in the operative region by chest imaging examination. Patients were followed up for 6 to 96 months, with one patient having wound swelling, ulceration, and sinus in the operative area of the chest wall defect in 12 months after surgery, which healed after phase Ⅱ operation; the incisions of chest wall defect wounds in other patients healed well and had no scar, redness and swelling, or sinus. Conclusions: Partially de-epithelized local flap could be used in repairing tubercular chest wall defect wounds, with the advantages of flexible flap design, minimal donor site injury, and good postoperative wound healing.

The Effect of Quilting Sutures on the Tension Required to Advance the Abdominal Flap in Abdominoplasty

Quilting sutures attaching the abdominal flap to the aponeurosis contribute to the prevention of seroma formation following abdominoplasty. The sutures distribute the tension over the subcutaneous tissue along the flap length, theoretically decreasing tension at the distal (cutaneous) end of the flap. This is expected to reduce the risks of necrosis, dehiscence, and enlarged or hypertrophic scars. This study sought to verify whether quilting sutures decrease the tension required to advance the dermal-fat flap in abdominoplasty. Thirty-four women undergoing abdominoplasty with quilting sutures participated in the study. The tensile force required for flap advancement was measured with a digital force gauge before and after placement of quilting sutures and then compared. Differences in tensile force were tested for correlations with BMI, age, weight of flap tissue removed, number of previous pregnancies, and postoperative complications, including seroma formation, hematoma, necrosis, dehiscence, and enlarged or hypertrophic scars. A mean reduction in tension of 27.7% was observed at the skin suture after the placement of quilting sutures (P < 0.001). No significant correlation was found between reduced flap tension and BMI, age, weight of tissue removed, or number of births. One case of seroma formation and 2 cases of enlarged scars were observed, but no case of hematoma, necrosis, or wound dehiscence was detected. The use of quilting sutures to attach the abdominal flap to the aponeurosis of the anterior abdominal wall reduced tension at the advancing edge of the flap in abdominoplasty.

Strategy of harvesting extended thoracodorsal artery perforator flaps for resurfacing the large soft-tissue defects of extremities

The authors presented their strategy to harvest extended thoracodorsal artery (TDA) perforator flaps for resurfacing the large soft-tissue defects of extremities. Thirty-three free extended TDA perforator flaps were harvested in 33 patients. The mean flap size was 145.2 cm2. The maximal flap length and the width were 30 cm and 10 cm, respectively. The color Doppler sonography (CDS) was used for preoperative assessment of perforators. Indocyanine green angiography (ICGA) was used for intraoperative assessment of flap viability in three patients. The vascular thrombosis, donor-site scar widening, and delayed recipient-site wound healing were not significantly related to the patient and flap characteristics. Flap tip or partial necrosis was significantly related to age and peripheral vascular disease. True positive rate, false negative rate, and positive predictive value of CDS for perforator identification were not different significantly between attending surgeon and residents. In the distance discrepancy of CDS, significant difference was found based on the classifications of perforator size, perforator type, and sonographic operator. The ICGA identified a hypoperfused distal area in a 30 cm long flap. The CDS locates the TDA perforators more precisely when scanned by experienced hands, in larger size or septocutaneous perforators. Using reliable and more perforators, applying muscle-sparing technique, considering suprafascial course of perforator and proper flap orientation are helpful in harvesting extended TDA perforator flaps. ICGA is an option for assessing flap viability, especially in elders and patients with peripheral vascular diseases.

The Efficacy of Local Flaps in the Treatment of Traumatic Scalp Defects.

Scalp defects represent a therapeutic challenge. The aim of this study is to present our experience with local and regional flaps in the treatment of trauma-induced scalp defects. Furthermore, a comparison with other surgical techniques was performed. A retrospective evaluation of patient records was performed. Only patients who underwent surgery using local flaps between January 2010 and September 2020 due to traumatic scalp defects were included in the study. In all, 10 cases were identified (3 females, 7 males, average age at surgery of 46.5 years [range: 18-82 years]). Six patients underwent surgery due to tissue defects and four due to scar keloids. Three patients experienced minor postoperative complications, one of which required additional surgery. The mean defect size was 35.75 cm2 (range: 4-79 cm2) among the four patients where the defect size could be determined retrospectively. The mean inpatient follow-up was 12.4 days (range: 2-34 days). Local flaps can be widely used. In carefully selected cases, they have the fewest disadvantages of all surgical techniques. In our experience, large angiosomes of the main scalp arteries allow the treatment of defects larger than 30 cm2 with local flaps. Our experience also suggests that the dimensions of flap length to flap width can exceed a ratio of 2:1 in the scalp.

The role of vein grafts in reconstructive head and neck microsurgery

ObjectiveFree tissue transfer is widely used for head and neck reconstruction. In certain circumstances, vein grafting is required to elongate free flap pedicles to connect them to appropriate recipient vessels. Because of controversy regarding the use of interposition vein grafts in free tissue reconstruction, this paper reports vein graft indications, techniques, safety, and outcomes for head and neck microvascular surgery. MethodsTwenty-six patients (23 men and 3 women) who underwent interposition vein grafting concurrent with free tissue transfer were included in this study. The most common reason for head and neck reconstruction with vein graft was tumor recurrence, followed by flap salvage. The interposition vein grafts were applied in two manners as temporary arteriovenous (A–V) loop and conduit to extend the length of the free flap for venous drainage. ResultsThe most common reconstructions were anterolateral thigh flaps (15 cases), followed by vastus lateralis myocutaneous (3 cases) and radial forearm (2 cases) flaps. The common recipient vessels were superior thyroid artery, superficial temporal artery and external jugular vein. The free flap loss rate was 7.7% with vein grafts and 4.9 without vein grafts (p = 0.380). The free flap complication rate was 50.0% and 16.8% in patients with and without vein grafts, respectively (p < 0.001). Radiation therapy, chemotherapy, prior neck dissection, and prior free flap transfer were more common in the vein graft group (all p < 0.001). The hospital stay was significantly longer for the vein graft group than for the non–vein graft group (29.5 vs. 19.0 days; p = 0.001). ConclusionOverall free flap survival rates of 92.3% and 95.1% in the vein and non-vein graft groups, respectively – indicating the reliability of the vein grafts in challenging head and neck reconstructions, particularly in salvage cases and patients with multiple reconstructions. Level of evidenceLevel 3.

Flow control for high-solidity vertical axis wind turbine based on adaptive flap

Adaptive flap as a new flow control technique with adaptability to the changing flow separation has recently attracted much attention. This study uses the adaptive flap to mitigate the flow separation of a vertical axis wind turbine with a high solidity of 0.75 and investigate its performance and flow control mechanism by considering different flap lengths and locations. The fluid flow is simulated using computational fluid dynamics with the shear-stress transport k-ω model, and the flap motion is calculated based on the fluid–solid interaction methodology. The results show that the flap can be adaptively raised by the backflow caused by flow separation and used to block the backflow. The blocking of the backflow alleviates the flow separation problem and increases the blades’ aerodynamic torque. However, the long flap causes a negative effect due to its inability to retract timely when the flow tends to the attached state at high tip speed ratio scenario. It is observed that the short flap can avoid this problem when it is located far from the blade leading edge. Also, the short flap located closer to the blade leading edge performs better at low tip speed ratios, even though the performance is observed to be weakened by the trailing edge vortices suppressing the flap from deployment. This study provides a technical approach and theoretical basis for better alleviating the flow separation problems in vertical axis wind turbine.

SAW1 is increasingly required to recruit Rad10 as SSA flap-length increases from 20 to 50 bases in single-strand annealing in S. cerevisiae

SAW1 is required by the Rad1-Rad10 nuclease for efficient removal of 3′ non-homologous DNA ends (flaps) formed as intermediates during two modes of double-strand break repair in S. cerevisiae, single-strand annealing (SSA) and synthesis-dependent strand annealing (SDSA). Saw1 was shown in vitro to exhibit increasing affinity for flap DNAs as flap lengths varied from 0 to 40 deoxynucleotides (nt) with almost no binding observed when flaps were shorter than 10 nt. Accordingly, our prior in vivo fluorescence microscopy investigation showed that SAW1 was not required for recruitment of Rad10-YFP to DNA double-strand breaks (DSBs) when flaps were ∼10 nt, but it was required when flaps were ∼500 nt in G1 phase of the cell cycle. We were curious whether we would also observe an increased requirement of SAW1 for Rad10 recruitment in vivo as flaps varied from ∼20 to 50 nt, as was shown in vitro. In this investigation, we utilized SSA substrates that generate 20, 30, and 50 nt flaps in vivo in fluorescence microscopy assays and determined that SAW1 becomes increasingly necessary for SSA starting at about ∼20 nt and is completely required at ∼50 nt. Quantitative PCR experiments corroborate these results by demonstrating that repair product formation decreases in the absence of SAW1 as flap length increases. Experiments with strains containing fluorescently labeled Saw1 (Saw1-CFP) show that Saw1 localizes with Rad10 at SSA foci and that about half of the foci containing Rad10 at DSBs do not contain Saw1. Colocalization patterns of Saw1-CFP are consistent regardless of the flap length of the substrate and are roughly similar in all phases of the cell cycle. Together, these data show that Saw1 becomes increasingly important for Rad1-Rad10 recruitment and SSA repair in the ∼20–50 nt flap range, and Saw1 is present at repair sites even when not required and may depart the repair site ahead of Rad1-Rad10.

Double Layer Lateral Crural Perichondrial Flap for Coverage and Stabilization of Tip Graft.

Tip plasty is the most important step of rhinoplasty. To achieve symmetrical cartilages with ideal tip rotation, projection and supratip break many techniques were defined. Besides suture techniques, tip grafts still maintain their importance and widely used among surgeons. However, graft visibility and distortion are the main drawbacks of this technique. In this study double-layered lateral crural perichondrial flap technique was introduced to prevent graft visibility and distortion as a novel technique. A total of 16 patients who underwent rhinoplasty with this novel technique were enrolled in this retrospective study. Patient satisfaction was assessed with Rhinoplasty Outcome Evaluation Questionnaire (ROE-Q). Graft visibility and asymmetry of tip defining point as an indicator of graft distortion were evaluated by two independent Plastic, Reconstructive and Aesthetic surgeons. Pre and postoperative photographs were taken and used for evaluation. A three-point Likert scale was used for assessment. Cohen's Kappa statistic and percent agreement test were usedtotest inter-rater reliability RESULTS: The mean follow-up time was 15 months (ranging between 12 and 19 months). According to the ROE-Q score, the mean total preoperative score was 6,25 and the mean total postoperative score was 18,06 (p<0,05). No or minimal evident graft visibility and asymmetry of tip defining point was observed in 12 patients and 10 patients, respectively. Mild evident graft visibility was observed in only 1 patient with thin skin. Severe evident graft visibility or asymmetry of tip defining point was not observed in none of the patients. The double-layer crural perichondrial flap was an effective and sufficient method for preventing graft visibility and graft distortion. Features like easy and fast flap elevation, no additional comorbidity, being autologous tissue and sufficient flap length and thickness make this technique valuable and useful. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Analysis of a Wing–Fuselage Biplane with Trailing-Edge Flaps in Low-Speed Flow

In this paper, the low-speed aerodynamic characteristics of a basic wing–fuselage supersonic biplane incorporating trailing-edge flaps are assessed using both wake and balance measurements. The effects of the flap attachment location, flap deflection, and flap length are evaluated. These experiments employed a flow velocity of and a Reynolds number of , along with a model having a simple three-dimensional wing–fuselage supersonic biplane configuration; and wake data were obtained with a five-hole probe. Installing the flap near the wingtip was found to produce strong interactions between the wingtip and the flap vortices in the wake, leading to significant induced drag at the wingtip. The local lift increases not only at the flap attachment location but also over the entire wingspan. Positioning the flaps near the body is determined to be more effective, and it gives rise to higher lift and smaller drag than in the case of installing the flap near the wingtip, due to the effects of the tapered wing configuration. The effects of the flap length and flap deflection are also confirmed, with longer flaps and larger flap deflection giving higher lift and more drag.

The Versatility of the DCIA Free Flap: A Forgotten Flap? Systematic Review and Meta-Analysis.

Studies reporting on the deep circumflex iliac artery (DCIA) free flap are restricted to a limited number of patients and areas of application. The aim of this review was to assess the reliability and versatility of the DCIA free flap during reconstruction. A comprehensive review was conducted in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines using PubMed, Web of Science, Cochrane CENTRAL, and SCOPUS. A critical analysis of pooled data was performed to assess outcomes employing the DCIA free flap. A total of 445 DCIA free flaps were included. The main recipient sites were head and neck (72.35%), lower extremity (20.67%), and upper extremity (6.74%). The main indications for reconstruction were tumor resection (73.8%) and trauma (17.43%). Fifty non-DCIA flaps were required to finalize the reconstruction of several defects. The pooled flap failure rate using the DCIA free flap was 4% (95% confidence interval: 1-8%). No significant heterogeneity was present across studies (Q statistic 22.12, p = 0.14; I 2 = 27.68%, p = 0.139). Complication rates for head and neck and limb reconstruction were 57.37 and 40.16%, respectively. The average length and surface area of bone flaps were 7.79 cm and 22.8 cm2, respectively. The area of the skin paddles was 117 cm2. The DCIA free flap has shown to be a versatile reconstructive alternative for head and neck and short-medium size limb defects. However, the complexity of functions, the recipient site location, and a potential large defect can detract from the use of the DCIA free flap as an initial reconstructive option for head and neck and extensive limb defects.

Lift Disturbance Cancellation with Rapid-Flap Actuation

Mitigation of vertical aerodynamic disturbances by means of a simple mechanical flap is investigated experimentally. A wall-to-wall NACA 0006 wing is bisected about the midchord for a 50%-chord flap length. Experiments are performed in a water tunnel at a chord-based Reynolds number of . The wing is driven in a sinusoidal vertical plunge motion as a spatially uniform, temporally varying surrogate to a vertical disturbance. Concurrently, the flap is actively deflected in a survey of kinematic parameters designed to suppress the influence of a plunge-induced disturbance. Plunge rates explored amount to disturbances incurred over a temporal range from one convective time to eight convective times. Two methodologies are employed to guide selection of flap deflection phase and amplitude necessary to preserve the baseline zero-lift state () of the undisturbed wing. In the first method, Theodorsen’s model is applied to arrive at an analytical solution to flap kinematics for a given prescribed plunge history. The theoretical derivation makes the standard assumptions of attached flow, planar wake, and no leading-edge vortical formations. Direct force measurements reveal reduction in lift transients by flap actuation of up to 87%, verifying the applicability of Theodorsen’s classical model. Further improvement is sought in a second method where empirical state-space modeling is formulated for lift cancellation. In this approach two separate lift models for wing plunge and flap deflection are constructed independently, and their superposition is employed to approximate the total lift in combined plunge and deflection motions. It is shown that although the empirical state-space approach performs similar to the inviscid theory of Theodorsen’s model, the empirical model proves more effective in suppressing the formation of the leading-edge vortex induced by plunge.

Prospective analysis of goal-directed fluid therapy vs conventional fluid therapy in perioperative outcome of composite resections of head and neck malignancy with free tissue transfer.

Background and Aim:Head and neck cancer surgeries with free tissue transfer are complex procedures, and fluid management can grossly affect the microvascular anastomosis. We hypothesise that intra-operative goal-directed fluid therapy (GDFT) is the key to administer fluid individualised to a patient's requirement. The aim of this study was to observe the role of GDFT in perioperative flap outcome and length of hospital stay.Methods:A randomised prospective controlled study was performed in 106 patients undergoing composite resection of head and neck cancer with free tissue transfer. Patients in Group A received GDFT based on stroke volume variation whereas Group B received conventional fluid therapy intra-operatively. The endpoints of this study were total perioperative fluid, fluid boluses, vasopressor requirement, flap outcome and length of intensive care unit and hospital stay. Statistical analysis was done using Chi-square test. Results:The total intra-operative fluid given to both the groups was comparable but patients in Group A received more boluses and vasopressors compared to Group B during intra-operative period. The amount of fluid given in the first 24 hours post-operatively was significantly less in Group A (1807 + 476 ml) compared to Group B (2205 + 382 ml). Incidence of hypotension with tachycardia was observed in three patients in Group B and none in Group A. Poor flap outcome was observed in one patient in Group A versus four in Group B due to thrombosis.Conclusion:GDFT helps in early detection of fluid deficit and may avoid complications arising due to inadequate microvascular perfusion during the peri-operative period.

Predictors of the surgical outcome of propeller perforator flap reconstruction, focusing on the effective safe distance between the perforator and the wound edge

BackgroundSoft tissue defects in the distal third of the leg and malleolus are difficult to cover and often require free tissue transfer, even for small-sized defects. Propeller flaps were designed as an alternative to free tissue transfer, but are reportedly associated with high complication rates. The aim of our study was to assess our institutional experience with the propeller flap technique and to predict its outcome in lower-limb reconstruction.MethodsAll patients who had undergone propeller flap reconstruction of a distal leg defect between 2013 and 2018 were included. Demographic, clinical, and follow-up data were analyzed.ResultsComplications occurred in 17 of 82 propeller flaps (20.7%), comprising 11 cases of partial necrosis and six of total necrosis. There were no significant differences in age, sex, body mass index smoking, diabetes mellitus, and soft tissue defect sites between the groups of patients with versus without flap necrosis (p > 0.05). In univariate analysis, there were also no significant differences between these two groups in the length and width of the fascial pedicle, and the ratio of the flap length to the flap width (p > 0.05). Interestingly, there were significant differences between the two groups in the distance between the flap perforator, the shortest distance from the perforator to the defect location, and the rotation angle of the flap (p < 0.05). In multivariable logistic regression analysis with odds ratios (ORs) and 95% confidence intervals (95% CIs), the shortest distance from the perforator to the defect location was a significant risk factor for flap complications (p = 0.000; OR = 0.806). Receiver operating characteristic curve analysis showed that when the shortest distance from the flap to the wound was less than 3.5 cm, the necrosis rate of the flap was markedly increased (AUC = 76.1); this suggests that the effective safe flap–wound distance was 3.5 cm.ConclusionsPropeller flaps are a reliable option for reconstruction in carefully selected patients with traumatic defects of the lower limb and malleolus. We found that the effective safe distance was 3.5 cm from the flap to the wound.

Superficial temporal axial pattern flap for facial reconstruction of skin defects in dogs and cats.

Report the use, complications and outcome of the superficial temporal axial pattern flap (STA) when used for closure of skin defects localised to the maxillofacial region in dogs and cats. Multi-centre retrospective cohort study. Medical records of dogs and cats treated with a STA flap for closure of skin defects were reviewed. Information regarding signalment, reason for axial pattern flap use, flap size, flap healing, postoperative complications including need for surgical revision and overall outcome were collected. Nineteen patients were included: nine dogs and 10 cats. Indications for the STA flap included closure of defects following excision of tumours (18/19, 94.7%) and fungal granuloma resection (1/19, 5.2%). 100% flap survival occurred in 17 of 19 flaps (89.4%). Postoperative complications occurred in eight of 19 flaps (42.1%). A major complication of full thickness partial necrosis of the flap occurred in one of 19 cases (5.2%), where the flap length exceeded recommended guidelines. Minor complications related to the flap were seen in four of 19 cases (21%). This included partial thickness flap necrosis, flap oedema and wound discharge. Complications related to the location of surgery (5/19, 26.3%) included mild ectropion, mild exposure of the eye, reduced ability to blink and subcutaneous emphysema. The STA flap is a good option for closure of a skin defect localised to the maxillofacial region. STA flaps were associated with a high percentage of survival and a low incidence of major complications.

Closure of a free osteofasciocutaneous fibula flap donor site using local skin grafts or flaps: A systematic review and meta-analysis.

In free osteofasciocutaneous fibula flaps, secondary donor sites are avoided using one of three local closure methods: full-thickness skin grafts (FTSGs), split-thickness skin grafts (STSGs), or flaps. This systemic review aimed to evaluate the differences in outcomes among the three groups of closure methods used for free fibula flap defects. In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, we systematically searched the PubMed and Web of Science medical databases from inception to January 2021 for articles focused on closure of the free fibula flap donor site using the lower leg area-local skin graft or flap-that mentioned the free fibula flap defect size, and/or complications of the donor site. Study characteristics, free fibula flap size, and short-term complication rates were extracted for analysis. The pooled complication rates and confidence intervals were calculated based on the random-effects model. Eleven studies were included in the qualitative synthesis, and ten studies were included in the quantitative synthesis (meta-analysis). The FTSG (n=79, 52.3%) was the most widely used method, while both STSG (n=36, 23.8%) and flap (n=36, 23.8%) were the least commonly used methods. The mean free fibula flap length and width were largest for the flap method (11.5 ± 2.5cm and 6.0 ± 1.8cm), and all closure methods were used for free fibula flap widths ≥3cm. Rates of partial and complete necrosis were highest for the FTSG method (20.3%, p=.95, I2 =0%) and lowest for the flap method (12.7%, p=.95, I2 =0%). This systemic review indicated that any closure method could be adapted for a free fibula flap width ranging from 3 to 9cm, and the flap method was associated with the lowest rate of short-term complications.

An anatomical appraisal of dynamic muscle transfer of the orbicularis oculi muscle

Facial nerve palsy can cause significant distress for patients. We investigated the innervation of the orbicularis oculi muscle (OOM) and assessed the viability of unipedicle contralateral muscle transfer to restore symmetrical and spontaneous blinking. Cadaveric dissection and measurements were performed on lite fixed cadavers (n=15). Medial innervation of the OOM was identified prior to raising and transposing a flap to the contralateral eyelid. Measurements were performed in-situ and following transposition. A medial ascending branch of the buccal nerve innervating the OOM was identified bilaterally in all cadavers. The average length of flap raised was 59.85mm (± 4.69mm) with no difference between the left and right. Flaps with pedicles not dissected off the bone covered 48% of the ciliary margin length (CM) and 62% of the palpebral length (PL). Flaps dissected off the bone covered 72% of the CM and 92% of the PL. The results demonstrate that a flap can theoretically transpose to >50% of the contralateral eyelid length. Increased coverage of the eyelid was achieved by releasing the pedicle from the underlying bone. Little attention was focused on buccal innervation of the eyelids, and this consistent medial pattern may allow an innervated flap transfer to restore symmetrical blinking, something that eludes modern paralysis surgery in a single-stage procedure.

The Nasoseptal Flap for Reconstruction of Lateral Oropharyngectomy Defects: A Clinical Series.

To study use of the nasoseptal flap (NSF) to reconstruct lateral transoral robotic surgery (TORS) oropharyngectomy defects. Retrospective case series. A clinical series of six patients undergoing NSF reconstruction of lateral TORS oropharyngectomy defects was retrospectively studied. All patients underwent TORS for the treatment of intermediate-risk human papillomavirus (HPV)-positive oropharyngeal squamous cell carcinoma of the lateral pharyngeal wall between January and June 2017. All patients underwent NSF reconstruction of lateral TORS defects with retrospective analysis of outcomes and complications. Six patients underwent NSF reconstruction of lateral TORS defects. Operative times decreased from 180 minutes to 90 minutes over the study period. There were two cases of partial flap dehiscence and partial necrosis. There were no major donor site complications. All patients had temporary nasal obstruction and crusting. Two experienced temporary aural fullness. In all patients, the lateral wall was mucosalized in 1-3 weeks. Cephalometric analysis of preoperative imaging revealed that patients with high-arched palates (>3 cm) and defect lengths that are longer than NSF flap lengths are poor candidates for this technique. This NSF is a vascularized, locoregional rotational flap that can reconstruct lateral TORS defects in salvages cases or those where the parapharyngeal carotid or mandibular bone are exposed. Postoperative morbidity is limited to temporary nasal dyspnea, aural fullness, and crusting. Preoperative imaging can determine which patient will have successful defect coverage. 4 Laryngoscope, 132:53-60, 2022.

Experimental study on the effect of bionic flap parameters on airfoil aerodynamic performance

The effects of bionic flap on airfoil performance were experimentally studied to provide theoretical support for the application of the bionic flap in aeronautical engineering. Seven kinds of bionic flaps were used to study the effects of the key flap parameters, including the flap angle, length, shape, and position, at a Reynolds number of Re = 0.8 × 106. At small angle of attacks (AoAs), the drag and pitching moment increased and the lift reduced when using the bionic flap. While at high AoAs, the lift increased and the drag reduced, which improved the airfoil stall characteristics. The configuration of deflection bionic flap had the smallest initial AoA for improving the airfoil stall characteristics in the seven kinds of bionic flaps. More than eight degrees of the effective AoA range for improving lift characteristics could be achieved. The maximum lift coefficient could be increased by 3.9%. Additionally, the control mechanisms of the flap under different flow conditions (attached flow and separated flow) were deeply studied. In the attached flow, the effective camber and thickness of the basic airfoil could be changed by the flap, resulting that the flow around the airfoil was affected, which in turn affected the Cl and the slope of the lift line. In the separated flow, the flap affected the flow around the airfoil by controlling the development of the trailing edge separation vortex. These research results confirmed the aerodynamic mechanisms for the formation of double layered feathers when birds land, and provided insight into application of bionic flaps in aeronautical engineering.

Numerical Investigation of Aerodynamic Characteristics of NACA 4312 Airfoil with Gurney Flap

This paper presents a two-dimensional Computational Fluid Dynamics (CFD) analysis on the effect of gurney flap on a NACA 4312 airfoil in a subsonic flow. These numerical simulations were conducted for flap heights 1.5%, 1.75%, 2% and 3% of chord length at fixed Reynold Number, Re (5×105) for different angle of attack (0o ~16o). ANSYS Fluent commercial software was used to conduct these simulations. The flow was considered as incompressible and K-omega Shear Stress Transport (SST) model was selected. The numerical results demonstrate that lift coefficient increase up to around 12o AoA (angle of attack) for NACA 4312 with and without gurney flap. For every AoA lift coefficient and drag coefficient presented proportionate behavior with flap height. However, lift co-efficient was decreased after around angle of attack due to flow separation. Maximum lift to drag ratio was found at around 4o AoA for every flap length and airfoil with flap of 1.5%C (chord length) had shown the most optimized aerodynamic performance through the analysis. This study concluded that airfoil with gurney flap displayed enhanced aerodynamic performance than the airfoil without gurney flap due to the delay in flow separation.

Principal component analysis of linear type traits to explain body conformation in Murrah buffaloes

Linear type traits are important in terms of reflecting breed standards and in giving information about the developmental ability of the animals. For data analysis, principal component analysis (PCA) is most important technique when variables are correlated. The aim of present study was to make linear type traits unrelated and reduce their number to the extent which could be used in explaining body conformation in Murrah buffaloes. Measurements were recorded on a total of 81 adult Murrah buffaloes maintained at Buffalo Farm, Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar for 11 linear type traits (top wedge angle, rump slope, rump width, hip bone distance, navel flap length, brisket distance, height at wither, body length, skin thickness at neck region, skin thickness at ribs region and skin thickness at rump region). Phenotypic correlations were calculated for considered traits and significant positive correlations varied from 0.26 to 0.67 in the present study. All 11 linear type traits were subjected to varimax rotated PCA with Kaiser Normalization to explain body conformation of Murrah buffaloes. Principal component analysis resulted into four components which described 69.522% of total variation and out of this, first component explained 28.678% variation. The communality ranged from 0.882 (rump slope) to 0.390 (naval flap length) and unique factors ranged from 0.118 to 0.610 for 11 different linear type traits. It was concluded that PCA was effective to reduce the number of variables required to explain the body conformation in Murrah buffaloes.