Hinge Flap Research Articles

Applications of Burow's Grafts in the Reconstruction of Mohs Micrographic Surgery Defects.

Surgical defects in anatomically challenging locations, such as near free margins or crossing cosmetic subunits, may present reconstructive challenges to the dermatologic surgeon. For selected defects, Burow's grafts may produce functional and aesthetic results in a single operative session. To describe the applications of the Burow's graft technique for the repair of defects after Mohs micrographic surgery. An institutional review board-approved retrospective database review of surgical defects repaired with Burow's grafting after Mohs micrographic surgery at the Medical University of South Carolina was performed. The general technique of Burow's grafting is described, emphasizing proper graft sizing and direction of tension vectors. Varying anatomic locations and defect types are presented, with site-specific considerations and operative photographs. Burow's grafting provides ideal color and textural match, preserves subunit boundaries, results in a compact single-site wound, and may avoid complications of alternate repair choices. The tension vectors produced in closing the graft's harvest site may be designed to prevent distortion of free margins. Burow's grafting may be combined with hinge flaps to repair deep or avascular defects. Burow's grafts are reproducible, aesthetic, and useful reconstructive choices for a variety of surgical wounds.

Corneal flap thickness with the Moria M2 single-use head 90 microkeratome in 72 consecutive LASIK procedures.

PurposeThis study aimed to evaluate the accuracy and consistency of corneal flap thickness in laser-assisted in situ keratomileusis (LASIK) with the Moria M2 single-use head 90 microkeratome.MethodsThe central corneal thickness of 72 (37 right, 35 left) eyes of 37 patients was measured by ultrasonic pachymetry preoperatively and intraoperatively after flap cut. The Moria M2 single-use head 90 microkeratome was used to create a superior hinged flap in all eyes. The right eyes were always operated on before the left eyes in each patient, using the same blade in all bilateral cases. All patients underwent LASIK for myopia and/or myopic astigmatism using VISX Star S4 platform.ResultsThe mean preoperative spherical equivalent refraction was −3.55±2.30 D (range: −0.625 to −11.00 D), preoperative central corneal thickness by ultrasonic pachymetry was 541±26.82 µm (490–600 µm) and steepest K was 44.08±1.49 D (40–46.75 D) in all eyes. The mean flap thickness was 136.97±20.07 µm (106–192 µm), 131.2±19.5 µm (91–192 µm), and 134.16±19.85 µm (91–192 µm) in the right, left, and both eyes, respectively. A positive significant relationship was found between flap thickness and preoperative ultrasonic pachymetry thickness. No significant relationship was found between flap thickness and the age, preoperative spherical equivalent, and preoperative steepest K. The difference between the first and second eyes was not significant. There were no major intraoperative and postoperative complications in all eyes.ConclusionThe Moria M2 single-use head 90 microkeratome cut relatively thicker flaps than were intended. The flap thickness range was quite wide. This was a disadvantage for the accuracy and consistency of corneal flap thickness.

Analysis of a Surgical Treatment for Persistent Urorectal Fistulas after Radical Cancer Surgery: A Comparison of Prostate Cancer and Rectal Cancer

Introduction: The study aimed to present our experience of surgical treatment for urorectal fistulas (URF) that develop after cancer surgery. Materials and Methods: Fourteen patients with URF who were treated at our institution from 2005 through 2015 were retrospectively analyzed. Among these, 7 patients had previous surgical treatment of prostate cancer (PC) and the other 7 had been treated for rectal cancer (RC). The fistula was resected through a perineal incision, and the urinary and fecal defects were separately closed with the hinge flap method followed by interposition of a muscle flap transfer. Results: The overall fistula closure rate was 79%. Although the closure rate of the URF was lower in patients with previous RC surgery compared to the PC patients (57 vs. 100%), it did not reach statistical significance. Conclusions: URF treatment using an interposition muscle flap offers a high success rate of fistula closure. However, complicated fistulas occurring after RC surgery involving the prostate or the seminal vesicle might be difficult to repair by this surgery alone.

Contralateral assessment of sub-Bowman keratomileusis (SBK) microkeratome suction duration on laser-assisted in-situ keratomileusis (LASIK) flap characteristics

PurposeTo describe the effect of prolonging the standard suction duration during laser-assisted in-situ keratomileusis (LASIK) and its effect on flap thickness and hinge length using sub-Bowman keratomileusis (SBK) microkeratome. MethodsFifty-six eyes (28 patients) were included and divided into 2 groups; Group-A: eyes with flatter corneas (36 eyes, 18 patients) and mean keratometric readings ranging from 40.13 to 43.71 diopters (D). Group-B: eyes with steeper corneas (20 eyes, 10 patients) with mean keratometric readings ranging from 43.85 to 46.72 D. One-Use-Plus SBK microkeratome was used for flap creation. For right eyes, flap was created immediately once suction was built up. In left eyes, the surgeon waited for 10 s after suction was built up before flap creation. Flap hinge length and flap thickness were measured using surgical caliper and ultrasonic pachymetry, respectively. ResultsStatistically significant differences were observed in corneal flap hinge size between right eyes versus left eyes, with a mean of 3.98 ± 0.48 vs. 3.78 ± 0.55 mm (p < 0.001). Mean flap thickness in both eyes did not prove to be statistically significantly different with either surgical technique (90.2 ± 1.68 vs. 90.07 ± 1.44 μm, p = 0.8). Sub-group analysis of Group-A vs. Group-B revealed hinge sizes that were significantly larger in steeper corneas (p < 0.01 and p < 0.05, respectively). However, flap thickness in both groups was unaffected by surgical procedure (p = 0.5). ConclusionsIncreasing suction duration increases flap hinge length and stabilizes the flap, especially in steeper corneas.

Buffet loading, dynamic response and aerodynamic control of a suspension bridge in a turbulent wind

This paper describes experiments relating to the buffet response and control of a section of a long-span suspension bridge deck elastically mounted as part of a wind tunnel experiment. The bridge section is subject to grid generated flow turbulence. Two grids are used — one is a standard biplanar grid, while the second is a new design that provides larger turbulence length scales. The buffet response results are compared with admittances calculated using unsteady, three-dimensional, lifting-surface theory that extends standard two-dimensional Sears׳ theory. The bridge deck heave and pitch responses are predicted with comparisons made with wind tunnel measurements. In order to suppress buffeting, and increase the deck׳s critical flutter speed, the deck model is fitted with controllable leading- and trailing-edge flaps. Two sets of passive controllers, which use the flap angles as the control inputs, are demonstrated and evaluated for their capability to suppress the buffet response of the deck and increase its critical flutter speed. The first set of controllers sense the deck׳s position (pitch angle and heave, or pitch angle alone), whilst the second set (which are mechanical controllers) sense the vertical velocity of the flap hinge points. The control system design problem is solved as a mixed H2/H∞ optimisation problem. The wind tunnel experiments show that these control systems can reduce considerably the deck׳s buffet response, whilst simultaneously increasing its critical flutter speed.

Outcome of Tracheostomy Closure in Oral Cancer Surgery Patients

Objective: We investigated the outcome of tracheal fistula in patients with oral cancer who underwent tracheostomy at the time of initial surgery. Study Design: retrospective study Methods: We retrospectively investigated the outcome of tracheal fistula in 57 patients with oral cancer who underwent tracheostomy. The patients were classified into three groups, which were patients in whom the tracheal fistula closed spontaneously (Group A), patients in whom closure of the tracheal fistula did not occur spontaneously and surgical closure was required (Group B), and patients in whom closure of the tracheostomy could not be achieved (Group C). The following factors were examined for associations with failure of spontaneous closure: patient demographics, primary tumor site, T classification, N classification, stage classification, presence or absence of neck dissection, presence or absence of reconstructive surgery, presence or absence of postoperative (chemo)radiotherapy, presence or absence of postoperative aspiration pneumonia, and duration of tracheal cannula placement. Results: Among the 57 subjects, Group A were 27 (47.4%), Group B were 23 (40.4%), and Group C were 7 (12.3%). In Group B, surgical closure with a hinge flap was performed in all 23 patients. We found that neck dissection and postoperative (chemo) radiotherapy were both factors that had an independent influence on whether closure of the tracheostomy could be achieved. Conclusion: Although early removal of the tracheal cannula is advantageous for improving the QOL of the patient, long-term cannulation does not interfere with spontaneous closure. Accordingly, it is necessary to carefully consider the timing of decannulation.

Construction of a Morphing Wing Rib Actuated by a NiTi Wire

The main goal of this paper is to analyze if it is feasible to employ a trained shape memory alloy wire as a linear actuator to modify the camber of a morphing wing rib. In order to achieve this purpose, a morphing rib with a compliant trailing edge was proposed, developed, and subjected to structural analyses to ensure its flexibility. After the rib configuration was set, it was manufactured by a 3-D printer. The NiTi wire used as actuator was trained by a thermomechanical procedure based on a cycling process with a constant load application to present the two-way shape memory effect. In that way, the wire presents a determined length at its low-temperature phase and a shorter one at its high-temperature phase. Since the wire contraction and the torque applied by it are two crucial factors to define the camber curvature, it was decided to study two different wire lengths: 103.5 and 152.1 mm. The aerodynamic performance of the morphing cambered airfoils was studied using XFOIL software and compared to that of conventional airfoils with single hinged flap. The results show that both morphing airfoils present better aerodynamic performance for small angles of attack.

Pre-operative chemoradiation for sinonasal undifferentiated carcinoma of the anterior nasal cavity resected through a lateral nasal flap approach

IntroductionSinonasal undifferentiated carcinoma (SNUC) is an exceedingly rare and aggressive tumor that carries a poor prognosis due to its non-specific presentation and advanced stage at time of diagnosis. Early detection and treatment are vital, with chemotherapy, radiation, and surgery all being viable options. The literature is sparse and there is no consensus for optimal treatment. In surgical candidates, the otolaryngologist must have a vast skill set in order to resect the tumor with wide margins and reconstruct the defect in hopes of returning the patient to their pre-morbid state. MethodsA 74-year-old female presented with a growing left nasal mass which was biopsied and found to be a sinonasal undifferentiated carcinoma originating from the anterior nasal cavity between the septum and upper lateral cartilage. The patient was treated with neo-adjuvant carboplatin with concurrent radiation, followed by resection through a lateral nasal flap. The defect was reconstructed with a contralateral septal hinge flap and septal cartilage graft with primary closure of the lateral nasal flap. ResultsIntraoperatively, no skin or cartilage invasion was noted and as such, nasal skin was spared and utilized for primary closure. At a follow-up of 3months, the patient had no evidence of recurrence and had a well healing repair site with satisfactory cosmesis. ConclusionsDespite the aggressive nature of SNUC tumors, neo-adjuvant chemo-radiation and surgical intervention with functionally and aesthetically minded reconstruction can provide patients with improved outcomes and decreased morbidity.

Adaptive aeroelastic control of nonlinear airfoil with multiple flaps under unsteady flow

In this paper, a fully adaptive control design is considered for a four-degree-of-freedom aeroelastic system that has structural nonlinearities and operates in an unsteady aerodynamic incompressible flowfield. By using the flap hinge torque of a trailing-edge flap surface in combination with a leading-edge active flap, a closed-loop controller that adapts for uncertainties in the system parameters is designed. An implicit observer is implemented in the control design to compensate for lack of measurements of the lag states that model the unsteady flow. The innovative Lyapunov-based control design procedure results in a partial-state feedback adaptive controller that is globally asymptotically stable. Numerical simulation results show the effectiveness of the control strategy; comparative simulations are run to illustrate the benefit of using twin flaps as opposed to the conventional single flap control design.

COMBINAÇÃO DE TÉCNICAS SIMPLES PARA RECONSTRUÇÃO DE UM DEFEITO COMPLEXO DA ASA DO NARIZ APÓS CIRURGIA DE MOHS

Os autores descrevem a combinação de um conjunto de técnicas simples para corrigir um defeito complexo da região malar, sulco nasogeniano e asa nariz. A utilização de um retalho ”em dobradiça” de tecido celular subcutâneo permite corrigir a profundidade do defeito, restaurar o contorno anatómico e a posterior utilização de um retalho simples ou enxerto. A utilização do retalho em dobradiça subcutâneo é uma excelente alternativa a retalhos interpolados para a reconstrução de defeitos complexos centro-faciais.

Scar hinge flap for inner lining reconstruction of full-thickness defects on the ala of the nose.

Reconstruction of inner lining of the nose often requires complex surgical procedures. To evaluate the scar hinge flap as an alternative reconstruction technique, 21 patients with full-thickness defects of the ala who received a scar hinge flap were retrospectively analysed. Twenty-one patients were included. The average defect size was 1.9 cm2. Cartilage grafts were used in 11 patients. For skin reconstruction the scar hinge flap was covered by local flaps, interpolated melolabial flaps, full-thickness skin grafts, or paramedian forehead flaps. The mean follow-up was 10.7 months. No severe complications were observed. The scar hinge flap is a safe and simple technique for reconstruction of the inner lining of the nose although it is limited being a two-stage procedure.

A persistent tracheocutaneous fistula closed with two hinged skin flaps and rib cartilage interpositional grafting

Persistent tracheal fistula after tracheostomy decannulation is a recognized sequel to long-term tracheostomy use, causing important morbidity including difficult to vocalization and control of air secretions, recurrent pulmonary infections, and cosmetic and social problems. Herein, we reported a new method for closure of persistent tracheocutaneous fistula with rib cartilages. Compared to other techniques previously reported, the variations of our strategy were the use of temporary metal-covered tracheal stent and the hinged turnover skin bi-flaps reinforced withrib cartilage grafts. Rib cartilages were useful in order to reconstruct the trachea and prevent stenosis. Since it become difficult to obtain the maintenance of the trachea stability until healing of suture was well established, a covered metallic stent was also inserted to avoid flap collapse. The stent was removed 3months later. Six months follow-up showed normal tracheal patency.

Complex nasal reconstruction using the combination of bilateral hinge flaps and frontal paramedian flap after Mohs surgery

The reconstruction of nasal surgical defects, especially when there is total thickness bilateral simultaneous involvement of the nasal ala, tip, and dorsum, ...

Scar hinge flap for inner lining reconstruction of full-thickness defects on the ala of the nose

Reconstruction of inner lining of the nose often requires complex surgical procedures. To evaluate the scar hinge flap as an alternative reconstruction technique, 21 patients with full-thickness defects of the ala who received a scar hinge flap were retrospectively analysed. Twenty-one patients were included. The average defect size was 1.9 cm2. Cartilage grafts were used in 11 patients. For skin reconstruction the scar hinge flap was covered by local flaps, interpolated melolabial flaps, full-thickness skin grafts, or paramedian forehead flaps. The mean follow-up was 10.7 months. No severe complications were observed. The scar hinge flap is a safe and simple technique for reconstruction of the inner lining of the nose although it is limited being a two-stage procedure.

Continuous robust control for aeroelastic vibration control of a 2-D airfoil under unsteady flow

In this paper, a particular class of 2-D aeroelastic systems accounting for structural nonlinearities in pitching displacement and operating in an unsteady aerodynamic incompressible flowfield description is considered. By using the flap hinge torque of a trailing-edge flap surface as the control input, a continuous controller is proposed to suppress the aeroelastic vibrations of the wing section model. The control design based on the choice of the pitching angle as the output variable yields a semi-global asymptotic stability result. Furthermore, the system is theoretically shown to be robust to external disturbances. Numerical simulation results verify the efficacy of the proposed control strategy toward suppressing aeroelastic vibration in both pre- and post-flutter flight speed regimes under a multitude of external disturbances.

Comparison of full 3D-RANS simulations with 2D-RANS/lifting line method calculations for the flow analysis of rigid wings for high performance multihulls

This paper reports about a comparison of a 3D RANS investigation to calculate the flow around wing sails with a method based on 2D RANS calculations of flow around wing profiles in conjunction with a lifting line method to account for 3-dimensional flow phenomena. The investigation focusses on rigid wings with two elements: a main element with a hinged flap, as they are currently used on some performance multihulls. Wing sails can be analyzed using conventional 3D RANS flow investigation methods; however the computational costs are quite high. Here an alternative approach is introduced. It is based on planar flow 2D RANS profile investigations in conjunction with a lifting line method to account for 3-dimensional flow phenomena and induced drag. The lifting line method uses an iterative approach to make use of non-linear profile lift coefficients. This approach is so computationally efficient that it can be combined with constrained optimization methods in order to optimize performance of the wing. The paper describes the motivation for the development, the lifting line theory and validation efforts. Some applications of the new method are shown, demonstrating the ability of the method to be used for wing sail design and operation optimization.

Nonlinear optimal wave energy converter control with application to a flap-type device

Wave energy converters (WECs) require active control to maximise energy capture over a wide range of sea conditions, which is generally achieved by making the device resonate. The exaggerated device motion arising at resonance, however, may result in nonlinear effects that are ignored by the linear models that are typically employed. In particular, nonlinear viscous forces are significant for particular device types, such as hinged flaps, which we take as a case study in this paper. The paper develops a general nonlinear WEC control methodology based on pseudospectral methods. The continuous time energy maximization problem is fully discretised (both state and control), and the optimal solution is obtained by solving the resulting finite dimensional optimization problem. By way of example, the nonlinear viscous damping for a hinged flap WEC is incorporate into the control model. It is shown that the ratio of energy captured to energy dissipated is significantly increased with the nonlinear controller, compared to the linear case.

Reconstruction of Full Thickness Ala Defect with Nasolabial Fold and Septal Mucosal Hinge Flap.

Reconstruction of a full-thickness alar defect requires independent blood supplies to the inner and outer surfaces. Because of this, secondary operations are commonly needed for the division of skin flap from its origin. Here, we report a single-stage reconstruction of full-thickness alar defect, which was made possible by the use of a nasolabial island flap and septal mucosal hinge flap. A 49-year-old female had presented with a squamous cell carcinoma of the right ala which was invading through the mucosa. The lesion was excised with a 5-mm free margin through the full-thickness of ala. The lining and cartilage was restored using a septal mucosa hinge flap and a conchal cartilage from the ipsilateral ear. The superficial surface was covered with a nasolabial island flap based on a perforator from the angular artery. The three separate tissue layers were reconstructed as a single subunit, and no secondary operations were necessary. Single-stage reconstruction of the alar subunit was made possible by the use of a nasolabial island flap and septal mucosal hinge flap. Further studies are needed to compare long-term outcomes following single-stage and multi-stage reconstructions.

Reconstructing Complex Central Facial Defects Involving Multiple Cosmetic Subunits

Defects of the central face can pose significant reconstructive challenges and are some of the most frequently encountered defects in facial reconstructive surgery. Familiarity with the repair of such defects is essential. At our institution, we have found that a systematic approach to central facial defects allows for superior results. We present that approach here using several cases to demonstrate the intraoperative planning involved. The cosmetic units and subunits within the defect must be identified. The defect must then be assessed for structural defects and deep soft tissue defects, which can be repaired utilizing cartilage grafts and hinge flaps respectively. Superficial defects of the cheek, lip, and nasal sidewall can then be assessed and repaired, taking advantage of the available tissue reservoirs using adjacent sliding flaps. The remaining distal nasal defect can then be repaired, depending on size, with a full-thickness skin graft, a cheek interpolation flap, or if necessary, a paramedian forehead flap. This systematic approach to reconstructing central facial defects simplifies seemingly complex reconstructive challenges and optimizes results.

Novel Nonlinear Control Design for a Two-Dimensional Airfoil Under Unsteady Flow

In this paper, a particular class of trailing-edge flap-controlled two-dimensional aeroelastic systems with structural nonlinearities in plunging and pitching, and operating in an unsteady aerodynamic incompressible flowfield, is considered. By using the flap hinge torque of the trailing edge flap surface as the control input, a partial state feedback continuous adaptive controller is proposed in order to suppress the aeroelastic vibrations of the wing section model. It is shown that the control design with respect to an appropriately chosen output variable yields an asymptotic stability result for all three of the pitching, plunging, and flapping degrees of freedom. Numerical simulation results clearly demonstrate the effectiveness of the control strategy toward suppressing aeroelastic vibration at both pre- and post-flutter flight speed regimes.