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Recently, inverters with a common ac and dc ground are gaining significant interest due to their zero common-mode voltage that made them particularly attractive for the solar photovoltaic application. However, the dc source current of the existing topologies is discontinuous, and their voltage gains are limited. This article proposes a novel common-ground-type boost inverter that achieves continuous dc source current with significantly enhanced dynamic voltage gain. It consists of one boost inductor, four capacitors, nine power MOSFETs, and two power diodes. Voltage boosting and generation of nine-level ac voltage are achieved concurrently within a single-stage operation. The operation of the proposed CGT-9L-BI inverter is analyzed. Simulation and experimental results are presented for validation.

Antibiotic-coated implants are increasing in prevalence in the treatment of fracture-related infections. Coated plates may be desirable in certain anatomic locations or to augment nail fixation. We describe a simple, reproducible technique for the fabrication of antibiotic-coated plates and our initial results of a small case series.

Unifocalization of the major aorto-pulmonary collaterals (MAPCAs) followed by intra-cardiac repair with ventricular septal defect (VSD) closure and restoration of right ventricle to pulmonary artery (RV-PA) continuity is the ultimate treatment goal in a case of VSD with pulmonary atresia (PA) and MAPCAs. It may be achieved in a single stage or may require multiple surgeries. We present a case of a 2 year old boy with VSD/PA who underwent single stage unifocalization of MAPCAs through midline followed by intra-cardiac repair using two polytetrafluoroethylene (PTFE) tube grafts; one for unifocalization and other as a bicuspid valved RV-PA conduit.

Background: Preventing substantial environmental hazards caused by noxious gases and solutes from sanitary landfills necessitates adequate regulations that require knowledge of the underlying mechanisms involved and the effect of various strategies. Mathematical models have been used to understand the development of landfill gas based on sequential biological growth and certain simple chemical and physical processes. Methods: The single-stage and multi-stage Monod landfill degradation model is based on a coupled system of rate equations containing a nonlinear term related to Michaelis- Menten kinetics of the enzymatic reaction. In this communication, an approximate analytical solution of the nonlinear differential equations is solved using a new approach of the homotopy perturbation method. Results: Substrate and biomass concentrations for the single-stage Monod landfill degradation model as well as biomass, solid, aqueous, acetic, and gases for the multi-stage model are derived for all possible values of parameters. Theoretical evaluations of the kinetic parameters such as the constant of Michaelis- Menten, mass-specific growth rate, half-saturation, and the death rate are reported. Conclusion: The accuracy of the proposed analytical expressions is validated by direct comparison with numerical simulations generated by MATLAB. A sensitivity analysis is presented to report the effect of all parameters on the governing model and the time required to reach the steady-state. The obtained analytical results are expected to contribute to a better understanding of the model and the effect of parameters and hence a better designing of experiments.

Multiligament knee injury with periarticular fractures are high-velocity injuries and generally require a staged treatment approach that involves multiple hospitalizations and results in delayed return to activity. We report a single-stage management technique for these injuries with arthroscopy-assisted reduction and internal fixation of a depressed tibial rim fracture with concomitant posterolateral complex repair, medial meniscal repair, and posterior cruciate ligament reconstruction., Technique Video Video 1 This video demonstrates single stage arthroscopy-assisted reduction and internal fixation of tibial rim fracture with posterior cruciate ligament (PCL) reconstruction and repair of posterolateral complex and meniscal injury. Examination under anaesthesia revealed a grade III PCL and posterolateral complex injury confirmed on imaging along with a depressed fracture of the anteromedial tibial rim. The first step in our technique is to address the depressed fracture with elevation and bone grafting under arthroscopy assistance and also to fix the fibular head avulsion using a cannulated cancellous screw and tension band wiring. In the second step, the medial meniscal tear is addressed using all-inside technique and inside-out technique and the PCL is reconstructed using hamstring graft. The third step is to stabilize the elevated tibial rim using a buttress plate.

BACKGROUND: Single-stage type I hybrid total aortic arch repair is a surgical treatment for extensive aortic arch disease, but the clinical outcomes were distinguishing. The purposes of this study were to share our experience and evaluate the perioperative safety and long-term durability. METHODS: Thirty-six patients who underwent single-stage type I hybrid total aortic arch repair in Fuwai Hospital between January 2010 and June 2020 were respectively reviewed. Early primary endpoint was defined as early composite adverse events, including mortality, multiple organ dysfunction syndrome (MODS), unplanned reoperation, stroke, paraplegia, acute renal failure (ARF) necessitating continuous renal replacement therapy (CRRT), respiratory failure and stents related complications. Long-term endpoints included late mortality, late aortic related reintervention and late adverse aortic events. When evaluating the early- and long-term outcomes, all patients were stratified into two subgroups by age (65 years). RESULTS: All patients acquired technical success. Early composite adverse events rate was 11.1% (4/36), in-hospital mortality was 8.3% (3/36). Average follow-up period was 48.0±35.3 months. Overall survival rate was 83.3% and 51.9% at 5 and 10 years respectively. Late aortic related reintervention occurred at one (3.0%, 1/33) patient and this patient died after reintervention. Overall freedom from adverse aortic events was 79.2% and 47.5% at 5 and 10 years respectively. Significant difference was not observed between the elderly and young subgroups, no matter in early- and long-term outcomes. CONCLUSIONS: Single-stage type I hybrid total aortic arch repair has achieved desirable outcomes in our center, which does not increase perioperative risk in the elderly patients, meanwhile, also acquire acceptable durability in the young patients. In conclusion, this surgery is a practical mini-invasive treatment for extensive aortic arch disease with strict and limited indications.

Traditional surgical strategies for dumbbell neuroblastoma entail, among others, high risk of spinal deformity. Less invasive procedures might reduce these sequelae, however, there is small evidence comparing different strategies. Indications of minimally invasive surgery in neuroblastoma are still developing. Our aim is to identify and analyze different surgical approaches described in the recent literature and to suggest a minimally invasive option. A systematic review of the literature was conducted in PubMed (Jan 2000–Dec 2021) to identify reports describing surgical resection of dumbbell neuroblastoma in children, according to the PRISMA guidelines. Only full-text articles were included. 7 articles met the inclusion criteria which, added to the present case, represent a total of 43 patients. All were retrospective studies, most of them small series. Tumor location was mostly thoracic. Most of combined approaches were performed in two stages. Spinal deformity after surgery was reported in 3 patients. Minimally invasive approach was described in only one paper, with no reported cases of its use in a single-stage combined surgery. We also report, to our knowledge, the first single-stage posterior neurosurgical approach combined with thoracoscopy for resection of a dumbbell neuroblastoma in an infant. Surgical resection of dumbbell neuroblastomas is challenging. There is no consensus on best surgical approach. Dumbbell tumors should not be considered a contraindication for minimally invasive surgery. A single stage and minimally invasive strategy is proposed.

Backgrounds: The main objective of Frontoethmoidal encephalomeningocele (FE) treatment are neural morbidities defect correction and aesthetically pleasing looks. Staged procedures are used to be performed in Indonesia. This article aimed to reveal the result of FE correction through the single-stage modified Chula technique (ST-MCT) procedure in collaboration with the neurosurgery team. Case Reports: A rare case of 5 years old girl diagnosed with FE was reported in this study. The FE was slowly increased in size, causing apparent facial deformity and the appearance of telecanthus. An ST-MCT procedure in collaboration with the neurosurgery team was conducted to correct the defects. The IOD values, IPD values, postoperative complications, and anesthetic improvements were evaluated in this study. Result: The patient was well after the surgery, with no complications and short length of stay. There were noted improvement of ICD, IOD and IPD postoperative follow up. At three years after the surgery ICD= 29mm; IOD= 26mm; IPD= 52 mm (normal range). Summary: ST-MCT procedure conducted in collaboration with neurosurgery team had shown excellent correction of ICD, IOD, and IPD values, no complication, shorter length of stay, and minimal scars. It considers as the most proper technique to reach a good result of correction and aesthetically pleasing looks in FE cases.

In this article, a single‐stage bridgeless LLC resonant converter with a constant frequency control method is proposed for a high‐brightness light‐emitting diode (LED) driver. LED strings require drivers with high power density and high efficiency. This article presents a novel LED driver circuit topology based on switch integration and the switching controlled capacitor (SCC) technique. By combining the merits of a totem‐pole bridgeless boost PFC unit and a high frequency SCC‐LLC half‐bridge resonant converter, the proposed topology can achieve high efficiency. Due to the SCC‐LLC circuit topology structure, constant frequency control of the LLC resonant converter is achieved by the regulation of the equivalent resonant capacitance. The proposed novel LED driver topology can automatically achieve soft‐switching characteristics and a high power factor. The operating principle of different operation modes and the characteristics of the proposed LED driver are analysed in detail. Finally, to demonstrate the feature of the proposed topology, a 100 W/70 V laboratory prototype is built. The satisfactory experimental results correspond with the theoretical analysis and parameter design.

For the last 32years, we have been using island groin flap successfully to cover the scrotal defects in a single stage with good results. This flap utility for single-stage urethral fistula repair was first reported by the senior author in 1987 and was published in Br J Urol.1We have performed single-stage repair of scrotal defects of medium and moderate size with this flap in 25 cases of Fournier's gangrene and in 4 cases of scrotal avulsion injuries due to road traffic accidents. All had good aesthetic results. More than 50% scrotal size defects were treated by a single groin flap alone. In cases with total loss of the scrotum, the groin flap was used along with two superior medial pedicle thigh flaps. Here, we have included cases of single-stage reconstruction of scrotal reconstruction by island groin flap alone. All our patients were operated under spinal anaesthesia. The results were satisfactory for the patients. We conclude from our 30 years of experience of utilizing this vascular island groin flap for a single-stage repair of scrotal defects of moderate size to be a procedure of better choice.

Introduction Paediatric burn is a common emergency presentation with a variety of treatment options available. Major parental concerns include pain, healing and scarring, in addition to high parental anxiety. Epiprotect® is a biosynthetic cellulose-based sheet, applied as a single stage first layer contact dressing following initial debridement. Materials and Methods A retrospective case control comparison study was carried out in our hospital on 28 patients, 14 with biosynthetic cellulose, and 14 with non-adherent gauze. Pain and parental anxiety were measured by the parental perception of child’s pain on Wong-Baker faces pain rating scale and STAI-6 questionnaire (compatible with the STAI-S scoring system) respectively in first clinic visit during outer dressing change. Scar score was calculated using the Vancouver scar scale (VSS). Results Patients in both groups had a similar demographic and clinical distribution of location, mechanism of burn, first aid, surface area and depth of burn. Pain and parental anxiety were significantly reduced in the cellulose dressing group (p = 0.0001). Time to complete healing were similar in both groups. Mean VSS scar score was 4 (1–5) in cellulose dressing group compared to 6 (4–11) in non-adherent gauze group (p = 0.0463). Two patients developed hypertrophied scar in non-adherent gauze group. The mean number of outpatient clinic visits in cellulose dressing group were 2.5 (1–5) as compared to 3 (2–6) in the non-adherent gauze group (p = 0.0607). Conclusion Single stage first layer application of biosynthetic cellulose dressing is associated with reduced pain, parental anxiety, and improved scarring. The dressing is safe and can be applied to patients with superficial and mixed depth burns.

Background Mastoidectomy is one of the common surgical procedures performed by the otologist. It is commonly done for cholesteatomatous chronic otitis media (CCOM) and can be performed as either canal wall up or down techniques. Most of the CCOM is associated with ossicular erosions which require ossicular chain reconstruction (OCR) which can be done either in one stage or multiple stages. A multitude of factors affects postoperative OCR results with tympanomastoidectomy. Among various factors, the status of the tympanic membrane and middle ear mucosa is quite essential. To date, there are no randomized or prospective studies assessing the integrity of pars tensa and status of the middle ear mucosa in hearing outcomes in single-stage tympanomastoidectomy using partial ossicular replacement prosthesis (PORP) in the literature. Therefore, this study is performed to correlate the integrity of pars tensa and middle ear mucosa condition with postoperative hearing results of single-stage canal wall down (CWD) tympanomastoidectomy with PORP. Results Forty-two patients with cholesteatomatous chronic otitis media underwent single-stage canal wall down mastoidectomy (CWD) and partial ossicular replacement prosthesis (PORP) placement. The statistical analysis was done to compare the results of postoperative hearing with the intraoperative integrity of pars tensa and middle ear mucosa status. The mean pre- and postoperative air-bone gaps (ABGs) of all cases were 23.9 dB and 21 dB, respectively, with no statistically significant difference. In the pars tensa intact group, the mean pre- and postoperative ABGs were 21.5 dB and 18.5 dB, respectively, and in the pars tensa not intact group, the mean pre- and postoperative ABGs were 25.7 dB and 22.8 dB, respectively, and both groups had statistically insignificant difference. The pre- and postoperative ABGs in the healthy middle ear mucosa group were 20.7 dB and 19 dB, respectively. Similarly, the pre- and postoperative ABGs in non-healthy middle ear mucosa were 24.4 dB and 21.2 dB, respectively. The differences were not statistically significant in both groups. Conclusion There was a statistically significant improvement in postoperative air conduction threshold (ACT) in all cases. The integrity of pars tensa and middle ear mucosa status did not affect the postoperative hearing outcome in single-stage CWD tympanomastoidecomty using PORP.

Soft tissue sarcomas about the patellar tendon necessitate wide resection and thus present a significant reconstructive challenge. This article describes the novel use of a synthetic mesh graft to reconstruct the knee extensor mechanism as a single stage procedure after wide en bloc resection of an extraskeletal myxoid chondrosarcoma (EMC) in a patient with an invasive mass that was intimately associated with her patellar tendon.

Optimal treatment of full‐thickness skin injuries requires dermal and epidermal replacement. To spare donor dermis, dermal substitutes can be used ahead of split‐thickness skin graft (STSG) application. However, this two‐stage procedure requires an additional general anaesthetic, often prolongs hospitalisation, and increases outpatient services. Although a few case series have described successful single‐stage reconstructions, with application of both STSG and dermal substitute at the index operation, we have little understanding of how the physical characteristics of dermal substitutes affects the success of a single‐stage procedure. Here, we evaluated several dermal substitutes to optimise single‐stage skin replacement in a preclinical porcine model. A porcine full‐thickness excisional wound model was used to evaluate the following dermal substitutes: autologous dermal graft (ADG; thicknesses 0.15‐0.60 mm), Integra (0.4‐0.8 mm), Alloderm (0.9‐1.6 mm), and chitosan‐based hydrogel (0.1‐0.2 mm). After excision, each wound was treated with either a dermal substitute followed by STSG or STSG alone (control). Endpoints included graft take at postoperative days (PODs) 7 and 14, wound closure at POD 28, and wound contracture from POD 28‐120. Graft take was highest in the STSG alone and hydrogel groups at POD 14 (86.9% ± 19.5% and 81.3% ± 12.3%, respectively; P

INTRODUCTION Segmental skeletal defects are very difficult to treat. The current options are lengthy procedures, require more than one surgery and plagued with many complications. The aim of this study is to assess the results of bone graft in surgicel as a synthetic membrane for reconstruction of segmental skeletal defects in one stage surgery. METHODS Fourteen patients with segmental skeletal defects were included in the study. The ages ranged from 20 to 54 years with an average of 32 years. The defects were due to high energy trauma in all cases. The size of the defects ranged from 5 to 12 cm with an average of 7 cm. They were located in the distal femur in 11 cases and middle third of the femur in three cases. All cases were treated by the synthetic membrane technique in one stage surgery. Surgicel was used as a synthetic membrane and both the fibular strut autograft and morselized allograft were used to fill the defects in all patients. RESULTS All cases healed without additional procedures after the index surgery except in three cases. The time-to-bone union ranged from six to 13 months with an average of eight months. After physiotherapy all patients regained good range of knee movements except two cases. The complications included deep wound infection in two cases, nonunion of the graft in one case and joint stiffness in two cases. CONCLUSION Primary bone graft in surgicel as a synthetic membrane is a good technique for management of post-traumatic bone defects. It reduces the time and number of surgeries required for reconstruction of this difficult problem.

Background: Stacked screws is a commonly used technique in single-stage revision anterior cruciate ligament (ACL) reconstruction in the setting of bone loss, but there are limited data to support its use. Hypothesis: Two configurations of a biocomposite stacked screws construct have similar fixation strength and linear stiffness as a primary ACL reconstruction construct in a biomechanical model. Study Design: Controlled laboratory study. Methods: A total of 30 porcine legs were divided into 3 groups. Group 1 underwent primary ACL reconstruction with a patellar tendon graft fixed into the femur, with an 8-mm biocomposite interference screw of beta-tricalcium phosphate and poly lactide-co-glycolide. For a revision ACL reconstruction model, groups 2 and 3 had bone tunnels created and subsequently filled with 12-mm biocomposite screws. New bone tunnels were drilled through the filler screw and the surrounding bone, and the patellar bone plug was inserted. Group 2 was fixed with 8-mm biocomposite screws on the side of the graft opposite the filler screw, while group 3 had the interference screw interposed between the graft and the filler screw. The construct was loaded at 1.5 mm/s in line with the tunnel until failure. Load to failure, linear stiffness, and mode of failure were recorded. Results: The mean pullout strength for groups 1, 2, and 3 was 626 ± 145 N, 653 ± 152 N, and 720 ± 125 N, respectively ( P = .328). The mean linear stiffness of the construct in groups 1, 2, and 3 was 71.4 ± 9.9 N/mm, 84.1 ± 11.1 N/mm, and 82.0 ± 10.8 N/mm, respectively. Group 2 was significantly stiffer than group 1 ( P = .037). Conclusion: Two configurations of a biocomposite stacked screws construct for a single-stage revision ACL reconstruction in the setting of bone loss show a similar fixation strength and linear stiffness to a primary ACL reconstruction at time zero in a porcine model. Clinical Relevance: In the setting of bone loss from tunnel malpositioning, a single-stage revision ACL reconstruction using a stacked screws construct may provide adequate fixation strength and linear stiffness.

Intraoral defects are increasingly reconstructed using free flaps. However, certain situations may render free flap reconstruction difficult. This study presents two cases with underlying comorbidities that underwent reconstruction of buccal defects involving the retromolar trigone (RMT), using a single-stage peninsula-shaped lateral tongue flap (pLTF). A 58-year-old woman and a 75-year-old man were diagnosed with left buccal squamous cell carcinoma and right buccal adenoid cystic carcinoma, respectively. The buccal defects extending to the RMT area were detected and covered with an ipsilateral posteriorly based pLTF after wide excision of the lesion. All flaps survived without any postoperative complications. Moreover, no tumor recurrences or functional problems were observed during the final follow-up. A single-stage pLTF is believed to represent a good alternative to free flaps in buccal and RMT defects.

Objective: To compare midvastus and subvastus approach regarding operative parameters(lateral retinacular release, operative time, neurovascular injury) and outcome (Knee Society Score, Straight Leg Raise) at 12 weeks in single stage bilateral total knee arthroplasty. Study Design: Randomized clinical trial study Place and Duration of Study: Institute of Orthopaedic Surgery and South City Hospital Karachi from 1st January 2016 to 31st December 2018. Methodology: Fifty two patients of both genders ofmore than 50 years with osteoarthritis grade III or IV and bony changes confirmed by AP and lateral radiographs of knee were included. Patients with previous knee surgeries including high tibial osteotomy, deformities >20°(on mechanical axis), any neuromuscular problem and BMI ≥30 were excluded. Final assessment was done at 12 weeks. Isometric quadriceps strength was assessed by holding of contraction in seconds during the lifting (10cm above the plinth) phase of SLR (patient lying supine).Knee score (preoperative and final follow-up) was performed by Knee Society Score. Results: Thirty five were females and 21 males with mean age 65.3 years (50-78 years). Mean body mass index was 27.8 Kg/m2 (26.4-29.9). In midvastus TKR, the mean operative time was 61.7 minutes (range 52-70) whereas the same was 68.3 minutes (range 58-74) in subvastus TKR with p value 0.002. Rate of lateral retinacular release (LLR) was significantly (p=0.011) different between the midvastus TKR 5 (8.9%) and subvastus TKR 11 (19.6%). Neither group had neurovascular injury or early infection of the knee. Active SLR in subvastus group was achieved in shorter time (mean 3.1 days) as compared to midvastus group (mean 4.7 days). There was no difference (p=0.173) in isometric quadriceps strength at 12 weeks between subvastus TKR (mean 18 seconds) and midvastus TKR (mean 17 seconds). Knee society pain and functional scores were comparable between the two approaches at final follow up. Conclusion: Subvastus exposure has advantage of achieving active straight leg raise earlier while midvastus has lower frequency of lateral retinacular release. No difference in hospital stay and postoperative pain scores. Both subvastus and midvastus approaches are safe and offer comparable Knee Society Score outcomes. Keywords: Midvastus, Subvastus, Total knee arthroplasty, Knee Society Score, Straight leg raise

Background: Infected nonunion of long bones after fractures is one of the most challenging complication to treat in clinical practice. It is commonly treated by a two-stage approach; controlling infection initially and then application of external fixator and bone graft. Treatment with Ilizarov had been the gold standard but is associated with few complications. The objective of the study was to evaluate the clinical, radiological and functional outcomes of infected non-union of long bones treated with single-stage bone grafting and external fixation.Material and Methods: This retrospective study was carried out at Orthopedics Department of Northwest General Hospital, Peshawar Pakistan from 2014 to 2019. Medical records of 17 patients, aged 32 years and treated with Single-stage bone grafting and external fixation were reviewed. Nonunion included 7 humerii, 5 femurs, 3 tibias and 2 radius/ulna. Preoperative plain radiographs for any sequestrum or sclerosed bone margins and baseline investigations (like CBC, ESR, CRP and Vitamin-D status) were reviewed. All patients underwent radical debridement, reaming of intramedullary canals, external fixation and autogenous bone grafting. The outcomes evaluated were union of the bone (clinically and radiologically), resolution of infection, complication rate and number of re-intervention surgeries.Results: Among 17 patients, 10 were males and 7 were females. After treatment, mean follow-up duration was 9.414.48 months (4–18 months). None of the patients were lost to follow-up, had recurrence of infection or required further surgery. The mean duration of bone union was 8.4  4.48 months (range 3 to 17 months) and all of the patients achieved infection free union with satisfactory functional outcome.Conclusions: Single-stage bone grafting and external fixation is an effective technique in terms of resolution of infection and satisfactory bone union without any complications and can be used as an alternative to Ilizarov for treating cases of infected nonunion of long bones.

Objective. This study was conducted to provide local data regarding the results and post-operative complications after single-stage resection and anastomosis for acute sigmoid volvulus, without intra operative colonic lavage. Study Design: Descriptive Cross Sectional. Setting: DHQ Charsadda. Period: May 2017 to December 2019. Material & Methods: This clinical study was done on 50 patients who presented with the signs and symptoms of acute sigmoid volvulus excluding those with complications of the illness such as gangrene, perforation and peritonitis. Surgery for all patients was carried out under General anaesthesia. All the patients underwent emergency resection and primary anastomosis, without mechanical bowel preparation. Data were collected regarding post operation complication and analysis by using SPSS version 23. Chi square test was used to compare at level of significance

Place: United States; International audience; BACKGROUND: We aimed to compare postoperative pain, functional recovery, and patient satisfaction among patients receiving one-stage medial bilateral or medial unilateral UKA (unicompartmental knee arthroplasty). Our main hypothesis was that during the first 72 postoperative hours, patients who underwent medial bilateral UKA did not consume more analgesics than those who underwent medial unilateral UKA.METHODS: A prospective case-control study was undertaken involving 148 patients (74 one-stage medial bilateral vs 74 medial unilateral Oxford UKA). The primary outcome was evaluation of the postoperative total consumption of analgesics from 0 to 72 hours. Next, the postoperative evolution of pain scores and functional recovery were assessed. Oxford Knee Scores were assessed preoperatively at 6 and 12 months with the occurrence of clinical or radiological complications. Finally, patient satisfaction was evaluated at the final follow-up.RESULTS: The cumulative sums of analgesic consumption (0-72 hours) calculated in the morphine equivalent dose were 21.61 ± 3.70 and 19.11 ± 3.12 mg in the patient and control groups, respectively (P = .30). Moreover, there were no significant differences in terms of pain scores (P = .45), functional recovery (P = .59, .34), length of stay (P = .18), Oxford Knee Scores (P = .68, .60), complications (P = .50), patient satisfaction (P = .66), or recommendations for intervention (P = .64).CONCLUSION: Patients who undergo one-stage medial bilateral UKA do not experience more pain and do not consume more analgesics than those who undergo medial unilateral UKA. A bilateral procedure is not associated with a lower recovery or a higher rate of complications, as functional outcomes at 6 and 12 months are similar to those of unilateral management.

Gears are paramout rotary mechanical equipment as its used in many industrial applications, for example in cars, industrial compressors and other applications. Therefore, monitoring the development of its condition is very important to prevent the aggravation of defects and stopping production. Friction between gears is causes of vibration but its representation in modeling and the analysis of its effect on the dynamic response is a very complex matter. In this study, the friction effect was studied by relying on equal load sharing formula and by relying on the sliding velocity direction of single-stage spur gears. The time domain was converted to the frequency domain, depending on the Fast Fourier Transform ( FFT ) method. Dynamic modeling results indicate that the friction between gears has a significant effect on the Vibration response of gearbox. This effect can be noticed by increasing the vibration amplitude in the time domain. It can also be seen by increasing the gear mesh frequency (GMF) amplitude and by increasing the amplitude of its harmonics in the frequency domain.

Residual dissections after type A repairs are common and can result in aneurysm formation. Surgery is complex and considered high risk, particularly if there is arch involvement. A single-stage "arch-first" technique via clamshell incision is an excellent option in certain circumstances and herein we detail a variation of this approach using a trifurcated graft.

Background The coexistence of intracranial arteriovenous malformation (AVM) and meningioma in a single patient is seldom reported, so the clinical profile, optimal management, and outcomes of these patients are mostly unknown. Methods We performed a systematic review of the SCOPUS and PubMed databases for case reports and case series on patients with both intracranial AVMs and meningiomas. Data on demographics, clinical characteristics, surgical management, and outcomes were collected. Results A total of 18 cases were reported in the literature, including the present case. The mean age at presentation was 54 years (range of 15–70 years), with no gender predilection. Most of the meningiomas and AVMs were frontal in location, and more than half of the lesions were contiguous. The most common presenting symptoms were seizures (67%), headache (44%), and weakness (33%). Majority of the patients underwent single stage meningioma and AVM excision (44%), followed by staged meningioma excision then AVM excision (17%) and meningioma excision only (17%). In all, 94% (17/18) of the meningiomas were excised compared to 72% (13/18) of the AVMs. Outcomes were reported in 15 patients; 80% were favorable, but there were 2 deaths and 1 tumor recurrence after 5 years. Conclusion The coexistence of an intracranial AVM with a meningioma is recognized but rarely reported in the literature. Individualized treatment should be employed in managing patients with concurrent lesions, and outcomes are generally favorable due to the benign nature of both these entities.

Objective To assess clinical outcomes in patients that underwent open single-stage complex abdominal wall reconstruction (CAWR) with biosynthetic mesh. Methods Retrospective observational study of two prospectively registered series of consecutive patients undergoing CAWR with either long-term degradable (LTD) Phasix™ or mid-term degradable (MTD) BIO-A® biosynthetic mesh in a single institution between June 2016 and December 2019. Results From 169 patients with CAWR, 70 consecutive patients were identified who underwent CAWR with either LTD or MTD biosynthetic mesh. More than 85% of patients had an incisional hernia that could be classified as moderately complex to major complex due to a previous wound infection (67%), one or more complicating comorbidities (87.1%), one or more complicating hernia characteristics (75.7%) or contaminated or dirty defects (37.1%). Concomitant component separation was performed in 43 of 70 patients (61.4%). Overall surgical site infection (SSI) rate in these CAWR patients was 45.7%. Seventeen of 70 patients (24.3%) had computed tomography (CT) - and culture-confirmed SSI in direct contact of mesh, suspicious of mesh infection. Mesh removal for persistent local infection occurred in 10% (7 of 70) after a median of 229 days since surgery. Salvage rate of mesh after direct contact with infection was 58.8%. All removed meshes were in the LTD group. Seven patients (10%) had a recurrence; four patients in the LTD group (10%) had a recurrence at a median follow-up of 35 months and three patients in the MTD group (10%) at a median follow-up of 11 months. Three of the seven recurrences occurred in patients with SSI in persistent and direct contact with mesh. Conclusions Comorbid patients undergoing open complex abdominal wall reconstruction are at high risk of postoperative wound complications regardless of which type of biosynthetic mesh is used. When in persistent and direct contact with infection, long-term biodegradable biosynthetic meshes may need to be removed, whereas mid-term biodegradable biosynthetic meshes can be salvaged.

Microtia reconstruction through manual carving of autologous rib cartilage has a steep learning curve, is operator dependent, is time consuming, requires multiple stages, and frequently results in suboptimal results with poor patient satisfaction. The use of temporoparietal fascia over polypropylene implants achieves excellent cosmetic outcomes in a single stage, although is burdened by infection and extrusion in some cases. We describe the development of a hybrid technique with a novel device that allows for standardization of the cartilaginous construct, minimization of the need for donor cartilage and operative time, and minimization of the number of stages. Clinical Trial: NCT03624608.

STUDY DESIGN: Retrospective study. OBJECTIVE: To evaluate and compare the outcomes of single stage surgery for Tandem Spinal Stenosis (TSS) in elderly (Age ≥65 years) and younger patients (Age

Since ages, the best alternative for fossil fuel generation is found from Renewable energy sources. One among them is the Solar energy which can produce solar power. Solar power can be taught as “Solar Electricity” and is the most practical, cleanest forms of Renewa-ble Energy. Solar Power Systems otherwise called as PV systems can be of various types like off-grid and on-grid systems. This paper, focuses on Grid connected solar electric system. The paper aims at modelling high performance Three Phase Single Stage Grid Connected Inverter. So as to achieve maximum output from the photovoltaic array, MPPT Tracking is connected. The conversion from DC output of photovoltaic array is done to AC so that it is fed into the grid, a IGBT based inverter is used which converts from DC to AC power. A Simulation model is developed in MATLAB Simulink and results are presented in the paper.

Bilateral knee dislocations are exceedingly rare in orthopaedics. Managing these injuries presents a difficult task given their high complication rate and guarded prognosis. We report the case of a 21-year-old male who presented to our institution with bilateral knee dislocations sustained in a motor vehicle collision. The patient subsequently underwent multiligament knee reconstruction surgeries for each knee at one and three weeks following the initial injury. At one-year follow-up, the patient has achieved a successful outcome and has returned to regular activities which include hiking and exercising at the gym.

Schwannoma of sinonasal origin are uncommon benign tumors of nerve sheath origin. Schwannomas arising from nasal septum usually come as a surprise in the histopathology report. Most of these tumors are amenable to complete removal via endoscopic approaches and no case of recurrence has been reported till date. The present report highlights a case of nasal septal schwannoma arising from posterior part of nasal septum in an elderly female, managed by complete surgical excision endoscopically under general anesthesia. The patient remains free of disease at 2 ½ years follow up. This case emphasizes a need of keeping this rare pathology in the list of differential diagnosis for nasal/ septal masses and a high index of suspicion for this condition for which a single stage low morbidity curative treatment can be offered to the patient.

Free muscle transfer for facial reanimation requires the sacrifice of motor nerves and muscles, which inevitably leads to donor site morbidity. To overcome this, the authors performed the interfascicular nerve splitting technique during neurovascular latissimus dorsi flap harvest. The aim of this study was to examine the efficacy of our interfascicular nerve splitting technique through the evaluation of donor site morbidity. Records of patients who underwent free latissimus dorsi flap using interfascicular nerve splitting technique between 2012 and 2016 were reviewed. Postoperative donor site morbidity was evaluated using electromyography, nerve conduction studies, and the Quick-Disabilities of Arm, Shoulder, and Hand questionnaire (QuickDASH). A total of 13 patients were analysed. Grades from electromyography and nerve conduction study were not significantly different between donor site and contralateral side (0.42±0.51 and 0.08±0.28, respectively, p = .073). QuickDASH scores showed different results over time. Preoperative QuickDASH scores averaged 1.57±2.34. At postoperative 6 months, the average QuickDASH score was 8.74±4.62, which was significantly different from the preoperative average (p = .001). At postoperative 12 months, QuickDASH scores averaged 2.62±3.19, which was an improvement from the postoperative 6-month score. However, it was not significantly different from the preoperative score (p = .059). The present study showed that interfascicular nerve splitting could minimize donor site morbidity. Also, our results suggest that the split nerve can function as a donor nerve. Our novel method could be a valuable option for minimizing donor site morbidity during facial reanimation surgery.

AimsPeriprosthetic joint infection (PJI) is a devastating complication following total knee arthroplasty (TKA). Two-stage revision has traditionally been considered the gold standard of treatment for established infection, but increasing evidence is emerging in support of one-stage exchange for selected patients. The objective of this study was to determine the outcomes of single-stage revision TKA for PJI, with mid-term follow-up.MethodsA total of 84 patients, with a mean age of 68 years (36 to 92), underwent single-stage revision TKA for confirmed PJI at a single institution between 2006 and 2016. In all, 37 patients (44%) were treated for an infected primary TKA, while the majority presented with infected revisions: 31 had undergone one previous revision (36.9%) and 16 had multiple prior revisions (19.1%). Contraindications to single-stage exchange included systemic sepsis, extensive bone or soft-tissue loss, extensor mechanism failure, or if primary wound closure was unlikely to be achievable. Patients were not excluded for culture-negative PJI or the presence of a sinus.ResultsOverall, 76 patients (90.5%) were infection-free at a mean follow-up of seven years, with eight reinfections (9.5%). Culture-negative PJI was not associated with a higher reinfection rate (p = 0.343). However, there was a significantly higher rate of recurrence in patients with polymicrobial infections (p = 0.003). The mean Oxford Knee Score (OKS) improved from 18.7 (SD 8.7) preoperatively to 33.8 (SD 9.7) at six months postoperatively (p < 0.001). The Kaplan-Meier implant survival rate for all causes of reoperation, including reinfection and aseptic failure, was 95.2% at one year (95% confidence interval (CI) 87.7 to 98.2), 83.5% at five years (95% CI 73.2 to 90.3), and 78.9% at 12 years (95% CI 66.8 to 87.2).ConclusionOne-stage exchange, using a strict debridement protocol and multidisciplinary input, is an effective treatment option for the infected TKA. This is the largest single-surgeon series of consecutive cases reported to date, with broad inclusion criteria. Cite this article: Bone Jt Open 2021;2(5):305–313.

The oretical and empirical dependences of contact rigidity in a fixed joint at the first and repeated loadings upon engineering methods of a joint surface treatment are presented. There are shown data on potentialities of engineering methods of treatment in support and increase of contact rigidity.

Background and Purpose: Complicated femur fracture represents a major challenge for the orthopedic surgeon, with failed internal fixation, nonunion with broken intramedullary nail (IMN), and infected nonunion among the complications. Mechanical instability, as well as the poor biological environment, is considered as a concern when treating these cases. The purpose of this study was to evaluate concomitant IMN and plate augmentation as a single-stage procedure for the management of multiply operated nonunited femoral shaft fractures. Materials and Methods: Between January 2015 and May 2018, nine patients (eight men) with an average age of 40.8 years (range 25–70) diagnosed as nonunion femoral fractures after an average of four previous surgeries (range 2–6). All patients were available for follow-up with an average of 22 months (range 12–36). Results: The average time for fracture union was 6.7 months (range 3–12); five patients needed bone grafting to compensate for the bone defect encountered during the initial procedure, and two patients required secondary bone grafting after 6 months follow-up. Two patients presented with surgical site infection which was treated by antibiotics and daily dressing. The average leg length discrepancy at last follow-up was 1 cm (range 0.5–1.5). No patient had a metalwork failure or needed removal of the implants. Conclusion: In treating complicated multiply operated nonunited femoral shaft fractures, we believe that this technique can provide a robust mechanical foundation as well as an improved biological environment for such nonunited fractures to heal.

Exotropia is a manifest outward deviation of the visual axes, which is either constantly or intermittently present. Untreated, poorly controlled intermittent exotropia later progresses to constant exotropia. Sensory exotropia is unilateral divergent misalignment of the eyes, resulting from loss of vision or long-standing poor vision in an eye. In sensory exotropia the angles are characteristically large, ranging from 30 to 100 prism dioptres (PD) and increases gradually over time as long as the cause of visual deficit remains active. Treatment is directed to re-establish the normal ocular alignment and binocular vision[1]. The preferred treatment for manifest exotropia is surgery[2]. Large angle constant exotropia negatively impacts the way the patients see themselves and are perceived by others. The benefits of surgical treatment of exotropia in adults is well proven, both psychologically and visually. The surgical treatment for largeangle exotropia has been a subject of sufficient debate. A variety of surgical plans have been described including two, three or four horizontal rectus muscles recession and resections with or without adjustable suture technique.[3] In more recent studies, the management of large-angle exotropia falls into two surgical approaches. Large bilateral lateral rectus recession is done when the acuity is good in each eye and indicated for true divergent excess type. For basic exodeviation R-R procedure is done popularly. Before embarking on surgical plan we do post occlusion test and identify the clinical type. If one eye is amblyopic, a maximal or supramaximal unilateral recess- resect procedure is performed. Records of previous studies have shown that monocular surgery had shown good results for exotropia of < 60 PD. But for exotropia of > 60 PD, monocular surgery was not so effective (4). In previous studies mild to moderate LR recessions were described but our study involves maximum recession on LR. In previous studies large LR recessions were reported to have complications like Lid changes and palpebral aperture widening. This study was done to evaluate the outcome of single stage, unilateral large LR recession with or without MR resection for constant exotropia

For medicolegal purposes, orthodontic or orthognathic treatment various stomatological staging technique for age estimation with appliance of conventional radiographic images have been published. It remains uninvestigated if cone beam computer-tomography delivers comparable staging results to the conventional radiographic stages of third molar analysis. We conducted a retrospective cross-sectional study of 312 patients aged 13–21 years. Dental age estimation staging technique, introduced by Nolla and Demirjian, were applied on the left lower third molar imaged by conventional panoramic radiographs and cone beam computer-tomography. It was investigated if 2D and 3D imaging presented different staging results for dental age estimation. In 21% the Demirjian’s staging differed by a single stage between 2 and 3D images. The greatest congruence (87%) between 2 and 3D images was revealed for stage 7 (G). In contrary, stage 5 (E) presented the lowest level of congruence with 47.4%. The categorization of Nolla revealed divergences in staging for than two categorical variables in Nolla’s stages 3, 4, 5 and 6. In general, the analysis of the data displayed the divergence for Nolla’s stages 4–8. The staging results for 2D and 3D imaging in accordance to the rules of Nolla and Demirjian showed significant differences. Individuals of 18 years may present immature third molars, thus merely an immature third molar cannot reject legal majority. Nolla’s and Demirjian’s 2D and 3D imaging present significantly different staging results.

Introduction This is a retrospective therapeutic series of eight cases of facial mucormycosis treated over a 15-year period to determine the safety of simultaneous debridement and free-flap reconstruction in facial mucormycosis. Methods Surgical debridement was done for three cases that presented acutely with systemic manifestations (group 1) and five cases that presented in the subacute phase without systemic manifestations (group 2). The debridement involved total maxillectomy with orbital exenteration in three cases, total maxillectomy with orbital preservation in two, and subtotal maxillectomy in three cases. A total of seven out of eight patients underwent reconstruction with free flap for defect closure; in one patient, only primary closure of mucosa was done. Results The mean follow-up was 20.5 months. Two patients with acute disease, where reconstruction was done, died in the postop period (on the 27th and 6th day post reconstruction, respectively) due to continuing infection and septic shock. One of the three (group 1), who presented acutely and underwent debridement alone, survived. Four of five patients in group 2 underwent successful free-flap reconstruction. The patient with free-flap loss was salvaged with an extracorporeal radial forearm flap. All except one patient had a soft-tissue free-flap reconstruction. Three of the six living patients reported for secondary surgery. The inability to achieve clear nonnecrotic surgical margins due to extensive disease was the reason for mortality in two patients in group 1. There was no mortality in any of the group 2 patients, even when debridement and free-flap coverage was done simultaneously. Conclusion Simultaneous debridement and free flap can be successfully implemented in select cases of facial mucormycosis

INTRODUCTION: Multi-ligamentous knee injuries (MLKI) are rare orthopedic injuries with diverse approaches to its management protocol. The purpose of this study was to determine the epidemiology of MLKI in our centre and its outcome in single stage reconstruction. METHODS: 60 patients who were surgically treated for MLKI between 2014 and 2018 were included in this study, data was collected pre and postoperatively and their Lysholm and IKDC scores were used to evaluate the outcomes. RESULTS: A male predominance was noted in the present study. Road traffic accidents (RTA) were the most common mode of injury (66.7%). ACL & MCL combination constituted the most common injury pattern (36.7%). 41.7% of our patients were treated within 3 weeks from injury and 58.3% were treated 3 weeks after injury and there was no statistically significant difference in their outcomes with a p value > 0.05 for their post op Lysholm scores and post op IKDC scores. Overall, there was a statistically significant difference in outcomes post surgery with regards to pre-operative and post-operative Lysholm and IKDC scores in our patients with a p value 3 weeks) surgery. Single stage surgical management of MLKI produce considerably better outcomes compared to staged management. It was also found that surgical management of MLKI with reconstruction could help patients to return to their pre operative level of sports activities with a proper rehabilitation protocol.

In recent years, there has been increased interest in transitioning total joint arthroplasty procedures from inpatient settings to ambulatory surgical centers to decrease costs and eliminate the need for hospital stays. In addition, simultaneous bilateral total hip arthroplasty (THA) has been found to be favorable in certain patient populations when compared with staged bilateral THA. In this study, we report the results of a series of three patients who underwent single-stage bilateral THA in a free-standing ambulatory surgical center with excellent short-term outcomes and no 90-day complications.

Over the decades, the Frozen Elephant Trunk (FET) technique has gained immense popularity allowing simplified treatment of complex aortic pathologies. FET is frequently used to treat aortic conditions involving the distal aortic arch and the proximal descending aorta in a single stage. Surgical preference has recently changed from FET procedures being performed at Zone 3 to Zone 2. There are several advantages of Zone 2 FET over Zone 3 FET including reduction in spinal cord injury, visceral ischemia, neurological and cardiovascular sequelae. In addition, Zone 2 FET is a technically less complicated procedure. Literature on the comparison between Zone 3 and Zone 2 FET is scarce and primarily observational and anecdotal. Therefore, further research is warranted in this paradigm to substantiate current surgical treatment options for complex aortic pathologies. In this review, we explore literature surrounding FET and the reasons for the shift in surgical preference from Zone 3 to Zone 2.