Surgical management of aerodigestive fistulas

Catedra chirurgie FECMF, USMF „Nicolae Testemiţanu″, Chişinău, Republica Moldova, Al XII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova cu participare internațională 23-25 septembrie 2015Scopul: Analiza experienţei Clinicii în problema fistulelor patologice eso-aeriene. Material şi metode: În ultimii 10 ani în Clinica noastră au fost trataţi 8 pacienţi cu fistule eso-aeriene, cu vârsta între 26 şi 62 ani, dintre care doar 2 erau femei. Factorii etiologici: arsură esofagiană, plăgi, leziuni endoscopice, diverticul, ventilaţie mecanică prelungită, traheostomia, etc. Simptomele clinice principale: tuse sufocantă la deglutiţie (semnul Ono) sau apariţia alimentelor în spută, traheostomă sau arborele traheobronşic. Diagnosticul a fost stabilit prin tomografie computerizată, esofagoscopie, fibrobronhoscopie. Rezultate: În 5 cazuri s-a intervenit chirurgical radical, iar în 3 cazuri paliativ – gastrostomie. Excizia fistulei, sutura traheii/bronhiei şi a esofagului a fost metoda de elecţie, aplicată la 4 pacienţi. Moment important intraoperator – plasarea lamboului muscular între esofag şi trahee, după sutura defectelor traheii şi esofagului, în regiunea cervicală fiind utilizat muşchiul sternocleidomastoidian, iar în toracotomii – lamboul din pleura parietală. În 2 cazuri s-a efectuat cervicotomia, inclusiv într-un caz cu sternotomie mediană parţială până la spaţiul intercostal 2, iar în 3 cazuri s-a efectuat toracotomia. La 2 pacienţi sa efectuat lobectomia şi sutura defectului esofagului, iar la o pacientă s-a efectuat esofagectomia şi plastia cu colon. Au decedat 4 pacienţi, inclusiv 2 postoperator, decesele fiind cauzate de complicaţiile pulmonare şi de insuficienţa poliorganică. Concluzii: Fistulele eso-aeriene sunt rare, polietiologice, complexe. Evoluţia gravă şi mortalitatea înaltă a acestora impun un diagnostic şi tratament chirurgical în centre specializate.Aim: Analysis of the experience in the management of aerodigestive fistulas. Material and methods: During the last 10 years, in our clinic were treated 8 patients with pathological communications between esophagus and tracheobronchial tree, aged between 26 and 62 years, only 2 of them were female. Among etiological factors were esophageal burns, wounds, endoscopical lesions, diverticula, long term mechanical ventilation, tracheostomy, etc. The main diagnostic symptoms were the Ono sign (coughing on swallowing) and appearing of food in tracheobronchial tree. The diagnosis was established by means of computer tomography, bronchoscopy, esophagoscopy. Results: In 5 cases radical surgery was performed, in 3 cases palliative – gastrostomy. The method of choice in radical surgery was fistula excision and suture of defects in esophageal and tracheobronchial walls. An important issue is the interposition of a muscular flap (sternocleidomastoideus muscle) in cervical approach, or a pleural flap (in thoracotomy approach), between esophagus and trachea or bronchi. In 2 patients we performed a cervical incision (in1 case with partial sternotomy to the level of the second intercostal space), in 3 cases – thoracotomy was performed, with lobectomy and suture of esophageal wall in 2 patients. In one patient we realized esophagectomy with coloplasty. Four patients died, including 2 patients after surgery, because of thoracic complications and multiorgan failure. Conclusions: Aerodigestive fistulas are rare, multietiological, complex diseases. Their severe evolution and high mortality impose management in specialized centers

Эндоскопические методы в диагностике и лечении женского бесплодия

Universitatea de Stat de Medicină şi Farmacie “N.Testemiţanu”, Catedra obstetrică şi ginecologie a FECMF, Şef catedră, Institutul Mamei şi CopiluluiThis article represents a compilation of literature search and personal clinical observations on the topic of female infertility and the use of endoscopic approaches in diagnosis and treatment of conditions related to it. The article outlines the need for the use of laparoscopy and/or hysteroscopy to assure a more precise and timely diagnosis and well as assessment of the severity of each condition. Specific examples are included.В статье представлены результаты данных литературы и собственных наблюдений эффективности использования эндоскопических методов диагностики и лечения женщин с бесплодием в браке. Обращается внимание на целесообразность проведения лапароскопии и гистероскопии в зависимости от причины бесплодия и степени тяжести патологического процесса, приводятся примеры тактики ведения пациентов в различных клинических ситуациях

Esophageal surgery – the experience of the department of surgery of CME faculty of SUMPh “Nicolae Testemitanu”

Catedra chirurgie FECMF, USMF „Nicolae Testemiţanu”, Chişinău, Republica Moldova, Al XII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova cu participare internațională 23-25 septembrie 2015Introducere: Esofagul, pentru chirurgi, rămâne un segment deosebit al tractului digestiv atât din cauza particularităţilor anatomo-topografice a organului, a căilor de acces către acesta, cât şi a tehnicilor operatorii asupra respectivului. Scopul lucrării: De a ne împărtăşi cu experienţa Clinicii de 30 ani în domeniul chirurgiei esofagiene. Material şi metode: Clinica de Chirurgie FECMF a USMF „Nicolae Testemiţanu” – secţia de chirurgie toracică şi chirurgie generală a Spitalului Clinic Republican îşi are direcţia cercetărilor, studiilor practico-ştiinţifice ale intervenţiilor pe esofag din 1974. Fişierul clinicii deţine mai mult de 1000 operaţii pe esofag. Rezultate: Punct de pornire au servit traumele esofagului adunând 70 cazuri. Alți 83 pacienţi – operaţi pentru diverticul, 192 cu hernii a hiatusului esofagian, 226 suferinzi de diferite forme de stenoze postcaustice, 118 pacienţi s -au operat pentru boala de reflux gastroesofagian, 115 cu achalazii, cu neoplasm esofagian s-au operat 92 pacienţi, esofag Barrett au avut 34 bolnavi, neoplasm al joncţiunii esofago-gastrice – 37 pacienţi. Avem 32 cazuri cu ruptură spontană de esofag (sindromul Boerhaave). Concluzii: Aceasta este experienţa Clinicii, în baza căreia s-a susţinut o teză de doctor habilitat şi două teze de doctor în medicină.Introduction: Esophageal surgery represents very special kind of digestive surgery, because of multiple factors – anatomical-topographic features, specific surgical access and surgical technique. Aim: To evaluate our clinical experience of 30 years of esophageal surgery. Material and methods: Since 1974, in the Department of Surgery of CME Faculty of SUMPh „Nicolae Testemitanu”, thoracic and general surgery departments of Republican Clinical Hospital, were performed about 1000 clinical cases of esophageal surgery. Results: Our first experience in esophageal surgery, as a start point was esophageal injuries – 70 patients, followed by esophageal diverticula – 83 patients, esophageal hiatus hernia – 192 treatment cases, esophageal stricture of various origin – 226 cases, 118 patients have been treated for gastro-esophageal reflux disease, 115 cases with achalasia of esophagus, 92 patients have been treated for esophageal cancer, 34 cases – with Barrett’s esophagus, gastroesophageal junction cancer – 37 cases. In addition, we have experience of 32 cases of spontaneous esophagus rupture (Boerhaave syndrome). Conclusions: The experience of the Clinic mentioned above was reflected in a thesis of doctor habilitatus of medical since and two thesis of doctor of medical since

Selection of optimal surgical treatment for esophageal diverticula

Catedra Chirurgie, Facultatea Educație Continuă în Medicină și Farmacie, USMF ”N. Testemițanu”, Chișinău, Moldova, Secția Chirurgie toracică, Spitalul Clinic Republican, Chișinău, Moldova, Al XI-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova și cea de-a XXXIII-a Reuniune a Chirurgilor din Moldova „Iacomi-Răzeșu” 27-30 septembrie 2011Rezumat. Introducere. Apariția pungii diverticulare esofagiene este condiționată de mulți factori: hiperpresiune intraesofagiana, tulburări de motilitate esofagiană, procese inflamatorii paraesofagiene - elemente ce acționează asupra unei zone anatomice de slabă rezistenţă parietală. O parte de pacienți care manifestă semnele clinice specifice necesită corecția chirurgicală. Material şi metode. În perioada 2000-2010 în secția chirurgie toracică SCR s-au aflat la tratament 41 pacienți cu diverticul esofagian. Topografic au fost diagnosticați diverticuli esofagieni cervicali – 27 (66%), bifurcaționali – 10 (24%) și epifrenali – 4 (10%) – ce corespunde datelor statistice din literatură. La 34 pacienți a fost efectuată intervenția chirurgicală. În majoritatea cazurilor (31 pacienți 91,2%) s-a practicat diverticulectomie prin abord cervical și toracic tradițional respectând detaliile tehnice specifice, în funcție de topografia pungii diverticulare. În 3 (8,8%) cazuri de localizare a diverticulului esofagian intratoracic s-a aplicat tratament chirurgical videotoracoscopic. Rezultate. Mortalitatea postoperatorie a fost nulă. Printre complicații postoperatorii precoce s- au întâlnit 2 cazuri de pleurezie exudativă rezolvată prin toracocenteză și 2 pacienți au avut disfagie temporară tratată medicamentos. În perioada de supraveghere medie de 5 ani complicații tardive și recidive nu au fost înregistrate. Concluzii. Tratamentul electiv al diverticulului esofagian este chirurgical și impune proceduri operatorii specifice și complexe, momentul determinant fiind particularitățile mobilizării colului diverticular. Diverticulectomia videotoracoscopică – etapa noua și de perspectivă în tratamentul diverticulului esofagian. Background. The appearance of esophageal diverticula is caused by several factors: intraesophageal hypertension, disturbance of esophageal motility, paraesophageal inflammation -all acting on the anatomic zones with weak parietal resistance. Some patients with specific clinical signs need surgical correction of this condition. Material and methods. In the period 2000-2010 in the department of thoracic surgery, Clinical Republican Hospital 41 patients were diagnosticated with esophageal diverticulum. Repartition of the patients according to diverticula topography as follows: cervical – 27 (66%), mid-esophageal – 10 (24%) and epiphrenic – 4 patients (10%) – this corresponds to observations from other studies. In 34 patients a surgical intervention was performed. In majority of cases (31 cases – 91.2%) a traditional diverticulectomy was used with cervical or thoracic approach depending on the topography of the diverticular pouch. In 3 cases (8,8%) of mid-esophageal diverticulum a video-assisted thoracoscopic surgery was performed. Results. No postoperative lethality was registered. Among early postoperative complications 2 cases of exudative pleurisy were observed and solved by thoracocentesis. Other 2 patients had temporary dysphagia treated conservatively. During the mean follow-up of 5 years late complications or recurrences were not registered. Conclusions. Surgery is elective treatment of esophageal diverticula, which needs specific and complex operative procedures. The main element of the intervention is proper dissection of the diverticular neck. Video-assisted thoracoscopic diverticulectomy opens new perspectives in the treatment esophageal diverticula.Background. The appearance of esophageal diverticula is caused by several factors: intraesophageal hypertension, disturbance of esophageal motility, paraesophageal inflammation -all acting on the anatomic zones with weak parietal resistance. Some patients with specific clinical signs need surgical correction of this condition. Material and methods. In the period 2000-2010 in the department of thoracic surgery, Clinical Republican Hospital 41 patients were diagnosticated with esophageal diverticulum. Repartition of the patients according to diverticula topography as follows: cervical – 27 (66%), mid-esophageal – 10 (24%) and epiphrenic – 4 patients (10%) – this corresponds to observations from other studies. In 34 patients a surgical intervention was performed. In majority of cases (31 cases – 91.2%) a traditional diverticulectomy was used with cervical or thoracic approach depending on the topography of the diverticular pouch. In 3 cases (8,8%) of mid-esophageal diverticulum a video-assisted thoracoscopic surgery was performed. Results. No postoperative lethality was registered. Among early postoperative complications 2 cases of exudative pleurisy were observed and solved by thoracocentesis. Other 2 patients had temporary dysphagia treated conservatively. During the mean follow-up of 5 years late complications or recurrences were not registered. Conclusions. Surgery is elective treatment of esophageal diverticula, which needs specific and complex operative procedures. The main element of the intervention is proper dissection of the diverticular neck. Video-assisted thoracoscopic diverticulectomy opens new perspectives in the treatment esophageal diverticula

Replantation of different anatomical segments of the upper limb

CNŞPMU, Conferinţa Naţională în cadrul Asociaţiei Ortopezilor – Traumatologi din Republica Moldova ”Actualităţi în microchirurgia reconstructivă”, Chișinău, Republica MoldovaÎn lucrare sunt analizate 34 cazuri de replantare ale segmentelor amputate a membrului superior. În total au fost replantate: degete – 34 cazuri, segmentul mîinei la nivelul oaselor metacarpiene –2; la nivelul oaselor carpiene – 2, la nivelul articulaţiei pumnului – 1, segmentul treimii distale a antebraţului – 1. Replantarea au fost reuşite în 20 cazuri (64.7%).In this study 34 cases replantation of amputated segments at different levels were analyzed. In total there were replanted: fingers – 34 cases, the hand segment at the level of metacarpal bones –2 cases; at the level of carpal bones – 2 cases, at the level of the wrist joint – 1 case, at the distal one-third of the forearm – 1 case. Replantations were successful in 20 cases (64.7%)

Radiation induced oscillations of the Hall resistivity in two-dimensional electron systems

We consider the effect of microwave radiation on the Hall resistivity in two-dimension electron systems. It is shown that the photon-assisted impurity scattering of electrons can result in oscillatory dependences of both dissipative and Hall components of the conductivity and resistivity tensors on the ratio of radiation frequency to cyclotron frequency. The Hall resistivity can include a component induced by microwave radiation which is an even function of the magnetic field. The phase of the dissipative resistivity oscillations and the polarization dependence of their amplitude are compared with those of the Hall resistivity oscillations. The developed model can clarify the results of recent experimental observations of the radiation induced Hall effect.Comment: 4 pages, 1 figur

Evolutionary trends in esophageal reconstruction

Catedra Chirurgie FEC MF USMF „N. Testemițanu”, Chișinău, Moldova, Secția chirurgie toracică, Spitalul Clinic Republican, Chișinău, Moldova, Al XI-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova și cea de-a XXXIII-a Reuniune a Chirurgilor din Moldova „Iacomi-Răzeșu” 27-30 septembrie 2011Introducere. Există diferite metode de substituție a esofagului rezecat în dependență de caracterul şi localizarea procesului patologic de calea de acces, de înlăturarea segmentară sau extirparea totală a organului, de materialul de substituție folosit şi metoda de ascensionare a grefei. Scopul: Relevarea tendințelor de reconstrucție a esofagului, în clinica de Chirurgie FEC MF. Material şi metode. În fişa noastră de observație (1977-2011) deținem 240 cazuri de intervenții reconstructive pe esofag. În timp ce registru de patologii indicate în rezecții de esofag, material de substituție utilizat şi căile de ascensionare ale transplantului rămân în ansamblu aceleaşi, în structura lor se observă diferite preferințe. Dacă în primele decade de lucru 90% din volumul total de intervenții dețineau operațiile pentru stenozele postcaustice, în ultimul cincinal (2007-2011) 56% din intervenții au constituit procesele neoplazice. Grefa gastrică serveşte drept material de substituție preferabil 40% (în trecut 17%), colonul deținea 48% acum 30%, jejunul rămâne la nivelul precedent - 30%. Cu referire la căile de ascensionare a grefei folosim mai frecvent calea prin mediastinul posterior – 40%, retrosternală – 25%, intrapleurală – 35%. Concluzii. Toate metodele de substituție a esofagului cu consemnarea avantajelor şi dezavantajelor în fiecare caz individual au dreptul la existență. În clinica Chirurgie FEC MF s-a stabilit următoarea tactică de reconstrucție esofagiană: 1) în stenozele postesofagita peptică și esofag Barrett - rezecția esofagului afectat cu substituția lui cu segment jejunal a la Roux prin laparotomie și toracotomia; 2) în cancerul esofagului mediu toracic - extirparea esofagului cu substituția lui cu grefă gastrică din curbura mare prin trei căi de acces – toracotomie, laparotomie, cervicotomie; 3) în stenozele postcaustice extinse și în cancerul treimii superioare a esofagului utilizăm extirparea esofagului cu substituția lui cu colon prin trei căi de acces. Introduction. There are different methods of substitution of resected esophagus, it depends on the type and localization of pathological process, surgical approach, segmental resection or total extraction of esophagus, depends on the material of substitution used and the method of graft preparation. Purpose. The development of reconstructive surgery of esophagus in the department of surgery, CME Faculty. Materials and methods. In our statement of observation (1977-2011) we have 240 cases of reconstructive interventions in the esophagus. While the indications for esophageal resection, replacement material used and methods of graft preparation remain the same, different preferences can be observed in their structure. If the first decade of work 90% of the total volume of interventions were operations for postcaustic stenosis, in the last five-year 2007-2011, 56% of interventions were the neoplastic processes. Gastric graft is preferable substitute material 40% (in the past 17%), colon had 48% now 30%, jejunum remains at the previous level of 30%. With reference to the way of ascension graft, frequently used path through the posterior mediastinum 40%, retrosternal -25%, intrapleural – 35%. Conclusions. All methods of replacement of the esophagus to record the advantages and disadvantages in each individual case have the right to existence. In the department of surgery CEM was established following tactics of esophageal reconstruction: • In stenosis after peptic esophagitis and Barrett esophagus – resection of esophagus and substitution with jejunal segment Roux by laparotomy and thoracotomy; • In medium thoracic esophageal cancer used esophageal extirpation and its substitution with gastric graft by thoracotomy, laparotomy and cervicotomy; • In extended postcaustic stenosis and cancer of the upper third of esophagus used esophageal extirpation by three pathways.Introduction. There are different methods of substitution of resected esophagus, it depends on the type and localization of pathological process, surgical approach, segmental resection or total extraction of esophagus, depends on the material of substitution used and the method of graft preparation. Purpose. The development of reconstructive surgery of esophagus in the department of surgery, CME Faculty. Materials and methods. In our statement of observation (1977-2011) we have 240 cases of reconstructive interventions in the esophagus. While the indications for esophageal resection, replacement material used and methods of graft preparation remain the same, different preferences can be observed in their structure. If the first decade of work 90% of the total volume of interventions were operations for postcaustic stenosis, in the last five-year 2007-2011, 56% of interventions were the neoplastic processes. Gastric graft is preferable substitute material 40% (in the past 17%), colon had 48% now 30%, jejunum remains at the previous level of 30%. With reference to the way of ascension graft, frequently used path through the posterior mediastinum 40%, retrosternal -25%, intrapleural – 35%. Conclusions. All methods of replacement of the esophagus to record the advantages and disadvantages in each individual case have the right to existence. In the department of surgery CEM was established following tactics of esophageal reconstruction: • In stenosis after peptic esophagitis and Barrett esophagus – resection of esophagus and substitution with jejunal segment Roux by laparotomy and thoracotomy; • In medium thoracic esophageal cancer used esophageal extirpation and its substitution with gastric graft by thoracotomy, laparotomy and cervicotomy; • In extended postcaustic stenosis and cancer of the upper third of esophagus used esophageal extirpation by three pathways

Epiphrenic esophageal diverticulum: clinical experience

Catedra Chirurgie FECMF, USMF „Nicolae Testemiţanu”, Spitalul Clinic Republican, Secţia Chirurgia Toracică, Chişinău, Republica Moldova, Al XII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova cu participare internațională 23-25 septembrie 2015Introducere: Diverticulul epifrenic se întâlneşte rar şi, de regulă, este asociat cu diverse tulburări de motilitate ale esofagului. Acuzele mai frecvente sunt disfagia, eructaţiile, durerile toracice şi manifestările pulmonare ale aspiraţiei. Examenul radiologic cu contrast şi cel endoscopic sunt prioritare la stabilirea diagnosticului, iar manometria esofagiană relevă tulburările de motilitate. Tactica chirurgicală optimală nu este încă materializată, subiect de dezbateri fiind morbiditatea perioperatorie şi mortalitatea postoperatorie înalte. Studiul dat relatează experienţa acumulată în tratamentul chirurgical al diverticulilor epifrenici. Material şi metode: Cercetarea include 25 bolnavi cu diverticul epifrenic internaţi în perioada 1970-2015. Evaluarea preoperatorie a inclus examenul radiologic baritat, examenul endoscopic şi testele funcţionale. Douăzeci de bolnavi au fost supuşi tratamentului chirurgical tradiţional, în 3 cazuri diverticulectomia a fost realizată prin tehnica minim invazivă, iar 2 bolnavi au beneficiat de tratament conservativ. Rezultate: Vârsta pacienţilor a fost cuprinsă între 20 şi 82 ani. Dimensiunile medii ale diverticulului au constituit 4,6 cm cu limitele absolute între 1,5 şi 12 cm. Durata media a bolii a constituit 22 luni. Acuzele predominante au constituit disfagia (88%) şi eructaţiile (71%). Mortalitatea postoperatorie a constituit 3,19%. Durata medie de spitalizare a fost de 17,2 zile. În 19 cazuri (76%) au fost înregistrate rezultate favorabile, iar în 3 cazuri au fost semnalate simptome reziduale. Concluzii: Diverticulectomia tradiţională transtoracică asigură o morbiditate postoperatorie redusă şi rezultate favorabile la distanţă. În cazurile necomplicate diverticulectomia poate fi realizată prin intermediul chirurgiei minim invazive.Introduction: Epiphrenic diverticulum is rare and usually is associated with various esophagus motility disorders. Frequent complaints are dysphagia, eructation, chest pain and pulmonary manifestations of aspiration. When revealing motility disorders, priority is given to contrast radiography and endoscopic examinations. The optimal surgical tactics has not been applied yet but it is being debated on the subject of perioperative morbidity and high postoperative mortality. This study recounts the experience in surgical treatment of epiphrenic diverticulum. Material and methods: Study involves 25 patients with epiphrenic diverticulum hospitalized during 1970-2015. Preoperative evaluation included barium radiographical, endoscopic examination and functional tests. Twenty patients underwent traditional surgery, in 3 cases diverticulectomy was performed by minimally invasive technique, 2 patients received conservative treatment. Results: Patients age ranges from 20 to 82 years. The average size of the diverticulum was of 4.6 cm with absolute limits between 1.5 and 12 cm. The average duration of disease was 22 months. Complaints of dysphagia (88%) and eructation (71%) prevailed. Postoperative mortality was 3.19%. The average duration of hospitalization was 17.2 days. In 19 cases (76%) there have been recorded favorable results and in 3 cases have been reported residual symptoms. Conclusions: Traditional transthoracic diverticulectomy ensures reduced postoperative morbidity and good long-term results. In uncomplicated cases diverticulectomy can be performed by applying minimally invasive surgery

Tracheo-bronchial surgery – the experience of the department of surgery of CME faculty of SUMPh “Nicolae Testemitanu”

Catedra chirurgie FECMF, USMF „Nicolae Testemiţanu”, Chişinău, Republica Moldova, Al XII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova cu participare internațională 23-25 septembrie 2015Introducere: Chirurgia traheo-bronhială este o parte componentă, dificilă a chirurgiei toracice. Paradoxul realizărilor moderne în reanimatologie şi terapie intensivă este că odată cu majorarea eficacităţii readucerii la viaţă a pacienţilor din come profunde (posttraumatice, septice, toxice) creşte numărul suferinzilor de complicaţii ale ventilaţiei asistate. Scopul: De a demonstra experiența şi posibilităţile chirurgiei toracice autohtone în acest domeniu. Material şi metode: Dispunem de un fişier propriu de 110 cazuri de intervenţii pe arborele traheo-bronhial. Stenozele traheale alcătuiesc majoritatea indicaţiilor pentru intervenţiile de reconstrucţie a traheii – 50 cazuri, urmează tumorile traheo-bronhopulmonare – 24, procesele inflamatorii cu cicatrizare şi stenozare a lumenului bronhial – 15, traumatismele traheo-bronhiale – 10, tumorile mediastinale – 6, fistulele traheo-esofagiene – 5. Rezultate: Am efectuat următoarele intervenţii chirurgicale: rezecţii – anastomoze circulare a traheii cervicale şi toracice – 31 cazuri, rezecţii „în pană” – 11, rezecţii de bifurcaţie a traheei – 4, rezecţia laringo-traheală cu osteoplastie – 8, lobectomii cu rezecţii bronho-anastomoză – 22, osteoplastie a membranei traheale – 15, sutura leziunilor traheo-bronhiale – 8, rezecţia bronho-anastomoză în stenozele posttraumatice a bronhiei primitive – 6, fistulele esofago-traheale – 5. Concluzii: Intervenţiile pe căile respiratoriii sunt de complexitate majoră şi necesită experiență vastă în chirurgia toracică şi colaborare strânsă cu serviciul anesteziologic şi bronhologic bine pus la punct.Introduction: Tracheo-bronchial surgery is a challenging part of thoracic surgery. In modern intensive care, paradoxically a greater number of patients with complications after mechanical ventilation occur, as the efficiency of resuscitation and intensive care in patients with profound comas (posttraumatic, septic, toxic) increases. Aim: To share the experience and possibilities of thoracic surgery in our department. Material and methods: A group of 110 patients were operated on the trachea-bronchial tree. Tracheal stenosis consisted the majority of indications for tracheal reconstructions – 50 cases, followed by tracheo-broncho-pulmonary tumors – 24, inflammatory processes with bronchial scar stenosis – 15, trachea-bronchial trauma – 10, mediastinal tumors – 6, tracheoesophageal fistulas – 5. Results: The following operations were performed: circular resections with anastomosis of the cervical and thoracic trachea – 31, marginal resections – 11, bifurcational resections – 4, laryngo-tracheal resections with osteoplastics – 8, lobectomies with bronchoanastomosis – 22, tracheal membrane osteoplasty – 15, suture of tracheo-bronchial injury – 8, bronchial resection followed by bronchoanastomosis for posttraumatic stenosis of primitive bronchus – 6, esophagotracheal fistulas – 5. Conclusions: Tracheo-broncho-pulmonary surgery poses significant complexity and requires great experience in thoracic surgery, as well as a strong cooperation with anesthesiology and bronchology teams

Absolute Negative Conductivity in Two-Dimensional Electron Systems Associated with Acoustic Scattering Stimulated by Microwave Radiation

We discuss the feasibility of absolute negative conductivity (ANC) in two-dimensional electron systems (2DES) stimulated by microwave radiation in transverse magnetic field. The mechanism of ANC under consideration is associated with the electron scattering on acoustic piezoelectric phonons accompanied by the absorption of microwave photons. It is demonstrated that the dissipative components of the 2DES dc conductivity can be negative ($\sigma_{xx} = \sigma_{yy} < 0$) when the microwave frequency $\Omega$ is somewhat higher than the electron cyclotron frequency $\Omega_c$ or its harmonics. The concept of ANC associated with such a scattering mechanism can be invoked to explain the nature of the occurrence of zero-resistance ``dissipationless'' states observed in recent experiments.Comment: 7 pager, 2 figure