Three-layer Technique Research Articles

Reconstruction following full-thickness excision of abdominal wall tumors: A prospective observational study conducted in a tertiary care Government Hospital in Eastern India

Background: Reconstruction of abdominal wall defects following full-thickness excision of large tumors (primary or metastatic) has always been a challenge for the treating surgeon. A number of reconstructive techniques have been described in the literature, including different types of meshes, flaps, and component separation techniques (anterior and amp; posterior), with varying results. We conducted a prospective observational study of our three-layer technique of abdominal wall closure at Medical College Hospital, Kolkata, to assess the long-time success of the procedure, especially in terms of hernia rates. Aims and Objectives: Reconstruction of abdominal wall defects following full-thickness excision of large tumors (primary or metastatic) has challenged surgeons for long, with several reconstructive techniques being described, with varying results. We conducted a prospective observational study of our three-layer technique of abdominal wall closure at Medical College Hospital, Kolkata, to assess the long-time success of our procedure, especially in terms of hernia rates. Materials and Methods: Thirteen patients with abdominal wall primary and isolated metastatic tumors were included from January 2017 to January 2022 with follow-up period from 8 to 60 months. Tumors were dermatofibrosarcoma protuberans, sarcomas, desmoid tumors, and two abdominal wall metastases. All patients in our study underwent computed tomography scan, core needle biopsy, and immunohistochemistry for better surgical planning. Results: Eight patients were male and five were female with mean age of 39 years and mean defect size of 10 cm. Polypropylene mesh was used, size varying from 15×15 to 30×30 cm with average operative time of 210 min. Post-operative superficial wound infection in 2 (15%), partial flap necrosis in 1 (7.6%), and tumor recurrence in one patient (7.6%) were seen. Conclusion: For closure of such large abdominal wall defects, our three-layer reconstructive technique has shown good results in terms of zero hernia rates. We recommend our method of closure, where affordability of biological meshes, availability of expensive meshes, accessibility to plastic and reconstructive surgeons or non-acquaintance with complex closure techniques are present.

3중 접합 공정에 의한 MEMS 공진기의 웨이퍼레벨 진공 패키징

3중 접합 공정에 의한 MEMS 공진기의 웨이퍼레벨 진공 패키징

Turbinate stitch: modification of Ahmed’s three-layered flap for oroantral fistulas. A technical note

Oroantral fistula is a communication between the maxillary sinus and the oral cavity. According to the literature, dental extraction is the most common cause, followed by maxillary cysts, benign or malignant lesions, and trauma. 1 Güven O. A clinical study on oroantral fistulae. J Craniomaxillofac Surg. 1998; 26: 267-271 Crossref PubMed Scopus (75) Google Scholar , 2 Yilmaz T. Suslu A.E. Gursel B. Treatment of oroantral fistula: experience with 27 cases. Am J Otolaryngol. 2003; 24: 221-223 Crossref PubMed Scopus (30) Google Scholar , 3 Abuabara A. Cortez A.L. Passeri L.A. et al. Evaluation of different treatments for oroantral/oronasal communications: experience of 112 cases. Int J Oral Maxillofac Surg. 2006; 35: 155-158 Abstract Full Text Full Text PDF PubMed Scopus (91) Google Scholar Various techniques have been described for repair of the fistula, using buccal fat, palatal rotational flaps, and serratus anterior flaps. 4 Môczair L. A new surgical method of closure of oroantral fistula of odontogenic origin. Ann Stomatol (Roma). 1930; 28: 1087-1088 Google Scholar A new and extremely effective method for addressing larger defects is a vascularised three-layered technique recently described by Darr et al. 5 Darr A. Jolly K. Martin T. et al. Three-layered technique to repair an oroantral fistula using a posterior-pedicled inferior turbinate, buccal fat pad, and buccal mucosal advancement flap. Br J Oral Maxillofac Surg. 2018; 56: 638-639 Abstract Full Text Full Text PDF PubMed Scopus (2) Google Scholar Recurrence and chronicity is a major issue, which is mainly due to trauma, sinus disease, or edentulousness. We describe a modification of the three-layered flap for better outcomes for recurrent oroantral fistula.

Optimal energy scheduling strategy for multi-energy generation grid using multi-agent systems

Due to high environmental concerns and ever-increasing fossil fuel costs, generation of clean energy and its optimal management considering the demand side responses are very essential to upsurge the productivity and reliability of the distribution grids. Hence, a kind of distributed microgrid identified as multi-energy generation grid (MEGG) has been proposed in this paper. The anticipated MEGG integrated with renewable energy resources, fuel cells (FCs), an alternative grid-supporting generator (AGSG) connected with boiler, micro-turbine (MT), and thermal system, wastes burning power plant (WBPP), and energy storage system (ESS) that investigate the optimal resource management in a grid under various operational conditions to minimize the emissions and operational costs. The problem is supervised by agents-based technique considering the generation capabilities and demand side responses. The three-layered technique is presented for the distributed optimal resource management based on multi-agent systems (MAS) framework, where different agents operate and perform tasks autonomously. An optimal energy management scheduling strategy is accomplished considering actions that guarantee the maximum use of generated renewable energy, eradicate the excess use of WBPP and FC, minimize AGSG operational time, and full-load demands satisfaction during the entire day. Similarly, coordination between the MEGG and central power grid has also been accomplished for the purpose to exchange power. For validation, three scenarios have been presented which shows that the combined utilization of distributed energy resources can profusely generate electricity having less emissions, recover the generation costs in peak hours, and enhance the reliability of the entire grid.

Modified Double-Layer Microsurgical Technique: Effective and Desirable Method for Vasectomy Reversal

Background: Family planning is one of the important needs of reproductive health care. For years, stable, reliable, reversible, accessible, and cost-effective methods have been desirable for this purpose. Vasectomy is often considered as the most common contraceptive method, due to the highly effective reversal success rate. Objectives: With the excellent patency and pregnancy rates, the microsurgical end-to-end vasovasostomy procedure has been recognized as a more common method for vasectomy reversal. Methods: Here we reviewed and analyzed the records of our experience of Modified Double-Layer microsurgical technique (MDLT) for the vasovasostomy procedure (n = 30) compared with the Three-Layer technique (TLT) (n = 24) during 3 years. The statistical analyses were carried out using SPSS (V. 15.0), and a value of P < 0.05 was considered significant. Results: In this report, 54 participants underwent TLT-VV (group 1) and MDLT-VV (group 2). There was no significant difference in the causes of vasectomy reversal between the two groups (P value = 0.392). There was no significant difference between study groups in the fertility history (P value = 0.561), the presence of a sperm granuloma (P value = 0.21), underlying diseases (P value = 0.345) and demographic characteristics. We observed a 94% (51/54) patency rate and a 40.7% (22/54) pregnancy rate without any need for Assisted Reproductive technique (ART). Conclusions: The microscopic vasectomy reversal operation brings advantages to family planning and sexual health. High throughput return fertility, without any need for ART, places this technique in the first step of family planning. It seems Modified Double-Layer technique may be considered as the first step of microscopic vasovasostomy.

Woven Textile Pressure Switch

In this paper has shown that the three-dimensional hollow weaving technique enables to produce a textile pressure sensor in one continuous process. Based on the multilayer fabric principle, the hollow woven fabrics can be created by connecting adjacent layers of the fabrics according to certain rules. The appropriate fabric structure has been selected and the three-layer weaving technique was used to make the textile pressure switch. The fabric structure is selected to ensure that the top and bottom layers are kept at a distance from each other. The electrically conductive tracks were embedded in the hollow structure of the fabric in bottom and middle layers. Three conditions must be fulfilled in order to create the textile switch: a) the fabric in normal condition keeps the shape required, i.e. the conductive elements are physically separated from each other; b) when the fabric is pressed, conductive elements are in contact, i.e. the switch is now in an electrically on state; c) after the pressure has been removed the fabric returns to its original position, i.e. switch is in an electrically off state. The behavior of the electrically conductive yarn and conductive tracks were tested in various ways. The stainless steel yarn woven in particular way can be used to create woven conductive tracks. Example of application: the pressure sensitive woven rug, the whole area or part of which acts as the pressure sensor or simple switch. The pressure switch in the floor coverings can turn on alarm systems or indicator lamps in the floor or wall coverings for guidance systems in public buildings.

Comparison of a purely endoscopic three-layer technique versus pericranial flap for reconstruction of anterior skull base defects after sino-nasal tumor resection: assessment of postoperative frontal lobe sagging and frontal lobe falling.

The evolution of endoscopic skull base approaches has enabled surgeons to manage selected skull base tumors through a transnasal endoscope-assisted approach. On the other side, more extensive lesions may require a combined cranioendoscopic approach. In this paper, we analysed and compared the incidence of frontal lobe sagging after endoscopic multilayer (EM) reconstruction versus pericranial flap (PF) reconstruction. Subjects were selected retrospectively according to specific inclusion and exclusion criteria. The degree of frontal lobe sagging after surgery was calculated based on the most inferior position of the frontal lobe relative to the nasion-sellar line defined on preoperative and postoperative imaging. A positive value signified upward displacement, and a negative value represented frontal lobe sagging. Twenty subjects were enrolled in our study. In the EM technique group the average frontal lobe displacement was -2,34 ± 1,55 mm. The average postoperative frontal lobe sagging was -0,45 ± 8,92 mm in subjects reconstructed with the PF. The skull base defect size correlated with the degree of frontal lobe sagging in subjects reconstructed with the PF, but not in the other group and when merging the two groups. In conclusion, the EM technique and the PF reconstruction showed a good reliability for the closure of anterior skull base defects. Moreover the PF seemed to prevent frontal lobe sagging but, for larger skull base defects, it could be useful to be combined with other autologous or heterologous materials to avoid the frontal lobe falling.

A Hybrid Low-Cost Bandpass Filter With SAW Resonators and External Lumped Inductors Using a Dual-Coupling Scheme

A class of hybrid low-cost bandpass filter (BPF) with only two kinds of circuit components, straightforward design procedure, and miniaturized circuit footprint is presented. The proposed BPF is based on a hybrid module composed of one type of surface-acoustic-wave (SAW) resonator and one external lumped inductor. Compared with traditional SAW-resonator-based BPF devices, the use of a single-SAW-resonator model for its design reduces the cost and complexity by avoiding the need for well-matched SAW-resonator pairs. The engineered filter topology consists of a dual-path coupling scheme, in which one coupling path is simply a series-type SAW resonator and another path is made up of two SAW resonators that are intercoupled by means of an external inductor in the middle. Such coupling architecture generates two additional transmission zeros (TZs) that allow to increase the out-of-band power-rejection levels and enlarge the stopband bandwidth. A circuit analysis based on the even-/odd-mode method is applied to derive its equivalent circuit that can be directly matched to a conventional transversal filter topology. The obtained equivalent circuit readily illustrates the operational mechanisms of the proposed filter principle in terms of reflection zeros and TZs. Subsequently, the quality factors of its even- and odd-mode-subnetwork resonators are analytically derived, and the obtained numerical results determine the tradeoff existing when choosing the external-inductor value among various performance metrics. For experimental validation purposes, two 418-MHz BPF prototypes formed by one and two in-series-cascade-connected second-order filtering units, respectively, are manufactured and tested. The circuit footprints of these filters are largely reduced by using a three-layer lamination technique for their physical implementations. The measured results show sharp-rejection filtering responses and are in close agreement with the theoretical predictions.

Investigation of RSW process on three-layer joining of steel to 6061-T8 aluminum

ABSTRACTIn this article, the RSW process (Resistance Spot Welding) on 6061-T8 aluminum alloy was studied. Spot resistance welding of two-layer plates is difficult and has very low mechanical properties. That is why this process is not practical for industrial applications. In this paper, a spot welding method was used with a novel three-layer technique, which means that an aluminum sheet was located between two sheets of steel and RSW was performed. The effects of RSW parameters including both current and welding time were investigated on the diameter of nugget, the microstructure of heat-affected zone and reaction layer, and mechanical properties. The results show that this method increases the tensile shear load compared with two-layer joining. Also, increasing of welding current, both tensile shear load and weld nugget diameter increased first, and then reduced. The interfacial reaction layer and weld heat-affected zone (HAZ) consisted of , .

Three-layered technique to repair an oroantral fistula using a posterior-pedicled inferior turbinate, buccal fat pad, and buccal mucosal advancement flap

Three-layered technique to repair an oroantral fistula using a posterior-pedicled inferior turbinate, buccal fat pad, and buccal mucosal advancement flap

Extended Endoscopic Endonasal Approach for Suprasellar Craniopharyngioma.

Objectives We illustrate a suprasellar craniopharyngiomas treated with an extended endoscopic endonasal approach (EEEA). Design Case report of a 43-year-old male affected by cerebral lesion located in suprasellar region involving the third ventricle and compressing the neurovascular structures, causing an anterosuperior dislocation of the chiasma. There is a complete disruption of the pituitary stalk that can explain the clinical finding of partial anterior hypopituitarism and hyperprolactinemia. The lesion is characterized by a solid and cystic component. Considering the absence of lateral extension and the suprasellar location of the lesion, an EEEA is preferred. Setting University Hospital “Ospedale di Circolo,” Department of Neurosurgery, Varese, Italy. Participants Neurosurgical and ENT Skull Base Team. Main Outcome Measures A bilateral parasagittal approach is performed using a four-hand technique. The first step of the surgery is the preparation of the Hadad's flap. The approach is extended to the planum sphenoidalis to expose the suprasellar region. The lesion is completely removed employing also an ultrasound aspirator. Skull base reconstruction is performed with three-layer technique: graft of fat tissue, fascia lata, and nasoseptal flap. Results No postoperative complications occurred. In the post-op, the patient presents a panhypopituitarism and an improvement in neurological status. The visual deficit remains stable. Post-op magnetic resonance imaging at 1 year documents the complete absence of pathological contrast enhancement. Conclusions EEEA is a feasible approach in treating craniopharyngioma with suprasellar extension. The advantages include optimal visualization, good resection rate, and absence of brain retraction. The link to the video can be found at: https://youtu.be/IYm-8P1jbBo .

Treatment of stage II medication-related osteonecrosis of the jaw with necrosectomy and autologous bone marrow mesenchymal stem cells

Treatment strategies for medication-related osteonecrosis of the jaw (MRONJ) remain controversial. Although the AAOMS suggests a conservative approach, a surgical management with necrosectomy is often required when conservative management has failed. Moreover, recent studies have shown promising results using an early stage surgical treatment. Over the past decade, cell-based bone regeneration utilizing bone marrow mesenchymal stem cells (MSCs) received increased attention. MSCs are known to promote wound healing and induce new bone formation in compromised tissue. Accordingly, the aim of this study was to assess the role of MSCs in the management of MRONJ. This study included 6 patients referred to our department with the diagnosis of MRONJ. Upon informed consent, the patients underwent surgical resection of necrotic bone followed by MSCs grafting. The MSCs were separated from bone marrow cells aspirated from the iliac crest using a bone marrow aspirate concentrate system. The MSCs were grafted into the defect with autologous thrombin and the defect was covered with a collagen membrane. In all cases, bony edges were rounded and the wound was closed using a three-layered technique. In the follow-up from 12 to 54months, all patients including those who had impaired conditions, sepsis, or pathological fracture, showed satisfactory healing with no signs of wound infection. This pilot study indicated that surgical management in combination with MSCs transplantation seems to be a promising treatment modality in the therapy of MRONJ.

Outcomes of the three-layer technique of nasal alar defect repair

Background Nasal defects are usually defined as 'partial' or 'full' thickness. The main role of reconstructive surgery is replacement of the defective tissues with nearly similar tissues. Design This study was a retrospective case series with chart review. The study was conducted at academic tertiary care medical centers. The aim of this study was to evaluate a three-layer reconstruction (functional and esthetic evaluation). Patients and methods Nine patients presented to our office with a defect in the lower third of the nose after an accident or secondary to nasal lesion removal. In our technique, we described a single-stage, three-layer reconstruction. This technique was used to repair the full thickness alar and lower lateral cartilage defects. We designed the new three-layer repair based on the normal anatomy and histology using bilobed skin flap and lateral nasal wall mucosal rotational flaps with septal cartilage graft. Results Aesthetically acceptable results were obtained without the compromise of the nasal valve function, which was assessed using acoustic rhinometry. The acoustic rhinometric evaluation for the nasal valve (1.5–2 cm from the nostril) function showed that the cross-sectional area on the repaired side was 0.46–0.78 cm2 and it was 0.52–0.81 cm2 on the other site (P = 0.670), with a normal nasal cycle and without compromising the airway. Moreover, minimal donor site morbidity was observed. Conclusion The bilobed skin flap and rotational mucosal flap with septal cartilage graft for full thickness alar defect, is a novel technique with minimal donor site morbidity, acceptable postoperative shape and good functional results.

Management of spontaneous cerebrospinal fluid leaks of the sphenoid sinus: our experience.

Closure of spontaneous sphenoid sinus cerebrospinal fluid leaks can be challenging because of the relative inaccessibility of the lateral recess and the presence of intracranial hypertension. We present our experience of such cases and highlight factors associated with a successful outcome. Eleven patients with spontaneous, laboratory confirmed, sphenoid sinus cerebrospinal fluid leaks were included. All patients underwent endoscopic closure by either a three-layer technique or fat obliteration. In all but one patient, the leak was successfully sealed (success rate, 90.9 per cent; mean follow up, 37.1 months). Elevated intracranial pressure was measured in eight patients, two of whom did not exhibit relevant clinical or radiological characteristics. Five patients received diuretics and dietary advice for weight reduction. In one patient with recurrence two weeks after repair, successful revision was performed by additional placement of a ventriculoperitoneal shunt (follow up, 67 months). Long-lasting cerebrospinal fluid fistula sealing in the sphenoid sinus requires stable reconstruction of the defect in three layers or fat obliteration if the anatomy is unfavourable. All patients should be intra- and post-operatively screened for elevated intracranial pressure to identify those who need additional intracranial pressure reduction measures.

Closure of tracheoesophageal fistula with two‐layer tracheal‐esophagoplasty and tracheal advancement

Closure of tracheoesophageal fistula with two‐layer tracheal‐esophagoplasty and tracheal advancement

Vasectomy reversal using a microsurgical three‐layer technique: one surgeon’s experience over 18 years with 1300 patients

The technique and the results of microsurgical vasectomy reversal in a single-centre study over 18 years are presented. Both vasovasostomy (VV) and epididymovasostomy (EV) were carried out in a three-layer technique. With strict adherence to the strategy, end-to-end VV was only performed if spermatozoa had been demonstrated at the epididymal stump of the vas. In all other cases, EV was carried out in a preocclusive region of the epididymal tubule. The outpatient procedure of refertilization was associated with a very low complication rate, which underlines its minimal-invasive character. The follow-up rate was 71%, the overall patency rate was 89% and the pregnancy rate was 59%. Secondary azoospermia was only observed in 1% of the patients. In relation to the intervals of obstruction, the patency and pregnancy rates were higher after short-term obstruction than after long-term obstruction. Correspondingly, higher success rates were found after VV than after EV. This is understandable because the probability for indication of EV increases with longer periods of obstruction. There is a significant discrepancy between patency and pregnancy rates that is likely to be caused by a relevant number of patients with post-operative asthenozoospermia. The duration of obstruction is an important factor concerning epididymal damage, but it only disproportionately affects the results of refertilization if the technology of EV is implemented consistently in case of an epididymal granuloma. Good clinical results are achieved with this strategy, as evidenced by pregnancy rates and semen analyses.

MgB 2 fabrication by diffusion-controlled three layered (B–Mg–B) technique

MgB 2 was successfully fabricated through diffusion-controlled three-layered (B–Mg–B) technique under high pressure. Due to melting temperature of Mg, the material was pre-heat treated at 600 °C between 1 and 48 h. Optimum pre-heat treatment condition was found to be 600 °C for 48 h. Then, the compacted material was grinded and pelletized under pressure of 2 ton. The pellets were heat treated at 600–900 °C for 1–48 h. Optimum heat treatment condition was determined to be 800 °C for 1 h for formation of almost pure MgB 2. Diffusion coefficient was determined with Fick's law and EDX data. Diffusion coefficient value for B in Mg matrix and Mg in B matrix was determined to be 1.66×10 −7 and 3.14×10 −8 cm 2/sn, respectively. Best T c value (39.4 K) was obtained for material heat treated at 800 °C for 1 h. A symmetric hysteresis was obtained for the best MgB 2 material and magnetization decreased with increase in the temperature and the applied magnetic field.

Endoscopic Transnasal Craniectomy in the Management of Selected Sinonasal Malignancies

Because of a better understanding of the anatomy from an endoscopic perspective, the acquisition of surgical experience, and concomitant technological advances, endoscopic resection of the anterior skull base (ASB) and overlying dura has now become a reality, opening new possibilities in the management of sinonasal malignancies. Here, the authors review a series of 62 patients, the largest reported to date, who underwent endoscopic transnasal craniectomy (ETC) and endoscopic dural repair for the management of selected sinonasal malignancies. Special emphasis is placed on the surgical technique, technical tricks, choice of materials for endoscopic dural repair, postoperative management, and complications. From 2004, 62 patients underwent ETC at two referral hospitals, which extended anteroposteriorly from the frontal sinus to planum sphenoidale and laterolaterally from the nasal septum to the lamina papyracea (unilateral resection, n = 28; 45%) or from papyracea to papyracea (bilateral resection, n = 34; 55%). Duraplasty with a three-layer technique was performed using the iliotibial tract and fat tissue. The most frequent histotypes were adenocarcinoma (58%) and olfactory neuroblastoma (22%). Forty-five (73%) patients were previously untreated. The incidence of early (T1-2, Kadish A-B) and advanced (T3-4, Kadish C) tumors was similar. The complication rate was 15%, mostly cerebrospinal fluid leaks (13%). Its prevalence did not correlate with patient age, medical comorbidities, previous treatment, presence of ASB involvement, or whether ETC was mono- or bilateral, but tended to correlate with advanced tumor stage, dural involvement, and the period of treatment. After a mean follow-up of 17.5 months (range, 1-54 months), 58 (94%) patients had no evidence of disease. In correctly selected patients with sinonasal tumors involving the ASB, ETC offers a less invasive alternative than resection by an open approach with an acceptable morbidity.

Multimillimetre-large superlattices of air-stable iron–cobalt nanoparticles

Self-organization of nanoparticles into two- and three-dimensional superlattices on a large scale is required for their implementation into nano- or microelectronic devices. This is achieved, generally after a size-selection process, through spontaneous self-organization on a surface, layer-by-layer deposition or the three-layer technique of oversaturation, but these techniques consider superlattices of limited size. An alternative method developed in our group involves the direct formation in solution of crystalline superlattices, for example of tin nanospheres, iron nanocubes or cobalt nanorods, but these are also of limited size. Here, we report the first direct preparation in solution of multimillimetre-sized three-dimensional compact superlattices of nanoparticles. The 15-nm monodisperse FeCo particles adopt an unusual short-range atomic order that transforms into body-centred-cubic on annealing at 500 degrees C. The latter process produces an air-stable material with magnetic properties suitable for radiofrequency applications.

Three-layer reconstruction for large defects of the anterior skull base.

To evaluate and discuss a three-layer rigid reconstruction technique for large anterior skull base defects. Prospective, nonrandomized, non-blinded. Tertiary teaching medical center. Twenty consecutive patients underwent craniofacial resection for a variety of pathology. All patients had large anterior cranial base defects involving the cribriform plate, fovea ethmoidalis, and medial portion of the roof of the orbit at least on one side. A few patients had more extensive defects involving both roof of the orbits, planum sphenoidale, and bones of the upper third of the face. The defects were reconstructed with a three-layer technique. A watertight seal was obtained with a pericranial flap separating the neurocranium from the viscerocranium. Rigid support was provided by bone grafts fixed to a titanium mesh, anchored laterally to the orbital roofs. All patients had a computed tomography scan of the skull on the first or second postoperative day. Patients were observed for immediate and long-term postoperative complications after such reconstruction. Postoperative computed tomography scans showed small pneumocephalus in all patients. It resolved spontaneously and did not produce neurologic deficits in any patient. There was no cerebrospinal fluid leak, hematoma, or infection. On long-term follow-up, exposures of bone graft or mesh, brain herniation, or transmission of brain pulsation to the eyes were not observed in any patient. Three-layer reconstruction using bone grafts, titanium mesh, and pericranial flap provides an alternative technique for repair of large anterior cranial base defects. It is safe and effective, and provides rigid protection to the brain.