Complete or partial obstruction of the duodenum by the superior mesenteric artery (SMA) is a rare cause of bowel obstruction. SMA syndrome results from the compression of the 3rd part of the duodenum between the superior mesenteric artery and the abdominal aorta. Causes include anatomical variation in the superior mesenteric artery, trauma, burns, surgeries, malignancy, and rapid weight loss. Diagnosis of SMA syndrome in patients may be difficult, as the clinical findings often resemble other forms of small bowel obstructions. This syndrome was first described in the literature by Carl Freiherr von Rokitansky in 1861. Subsequently, David Wilke provided a comprehensive description of the disease in a series of 75 patients. There has been skepticism about the existence of SMA syndrome due to scant literature reports and non-specific symptomatology. However, modern cross-sectional imaging has confirmed the existence of this rare syndrome. Here we present the case of a 50-year-old female with longstanding symptoms of gastrointestinal discomfort, weight loss, nausea, and vomiting. She underwent an exhaustive gastrointestinal workup until a diagnosis of SMA syndrome was made. We elected to proceed with a minimally invasive three-port laparoscopic, trans-mesenteric side-to-side duodenojejunostomy. The patient was discharged on postoperative day one after tolerating a regular diet. On one month follow-up, our patient reported improvement in symptoms with no postprandial pain or nausea and normal bowel movements. In conclusion, we report a case of superior mesenteric artery syndrome in a patient with recurrent abdominal pain and nausea. CT scan has the highest sensitivity for the diagnosis of SMA syndrome, findings suggestive of the diagnosis include an abnormal aortomesenteric angle and distance. While supplemental tube feeds and gastric drainage may resolve the condition without the need for surgery, this often takes many weeks to months to be effective. Minimally invasive surgical bypass is an attractive option because of the rapidity of symptom resolution, lack of need for long-term invasive tubes, short inpatient length of stay, and high success rate.

Deep learning approaches have been explored for surgical tool classification in laparoscopic videos. Convolutional neural networks (CNN) are prominent among the proposed approaches. However, concerns about the robustness and generalisability of CNN approaches have been raised. This paper evaluates CNN generalisability across different procedures and in data from different surgical settings. Moreover, generalisation performance to new types of procedures is assessed and insights are provided into the effect of increasing the size and representativeness of training data on the generalisation capabilities of CNN. Five experiments were conducted using three datasets. The DenseNet-121 model showed high generalisation capability within the dataset, with a mean average precision of 93%. However, the model performance diminished on data from different surgical sites and across procedure types (27% and 38%, respectively). The generalisation performance of the CNN model was improved by increasing the quantity of training videos on data of the same procedure type (the best improvement was 27%). These results highlight the importance of evaluating the performance of CNN models on data from unseen sources in order to determine their real classification capabilities. While the analysed CNN model yielded reasonably robust performance on data from different subjects, it showed a moderate reduction in performance for different surgical settings.

With the growing adoption of laparoscopic surgery practices, high quality training and qualification of laparoscopic skills through objective assessment has become critical. While eye-gaze and instrument motion analyses have demonstrated promise in producing objective metrics for skill assessment in laparoscopic surgery, three areas deserve further research attention. First, most eye-gaze metrics do not account for trainee behaviors that change the visual scene or context that can be addressed by computer vision. Second, feedforward control metrics leveraging on the relationship between eye-gaze and hand movements has not been investigated in laparoscopic surgery. Finally, eye-gaze metrics have not demonstrated sensitivity to skill progressions of trainees as the literature has focused on differences between experts and novices although feedback on skill acquisition is most useful for trainees or educators. To advance eye-gaze assessment in laparoscopic surgery, this research presents a three-stage gaze based assessment methodology to provide a standardized process for generating context-dependent gaze metrics and estimating the proficiency levels of medical trainees on surgery. The three stages are: (1) contextual scene analysis for segmenting surgical scenes into areas of interest, (2) compute context dependent gaze metrics based on eye fixation on areas of interest, and (3) defining and estimating skill proficiency levels with unsupervised and supervised learning, respectively. This methodology was applied to analyze 499 practice trials by nine medical trainees practicing the peg transfer task in the Fundamental of Laparoscopic Surgery program. The application of this methodology generated five context dependent gaze and one tool movement metrics, defined three proficiency levels of the trainees, and developed a model predicting proficiency level of a participant for a given trial with 99% accuracy. Further, two of six metrics are completely novel, capturing feed-forward behaviors in the surgical domain. The results also demonstrated that gaze metrics could reveal skill levels more precisely than between experts and novices as suggested in the literature. Thus, the metrics derived from the gaze based assessment methodology also shows high sensitive to trainee skill levels. The implication of this research includes providing automated feedback to trainees on where they have looked during practice trial and what skill proficiency level attained after each practice trial. / Master of Science / Laparoscopic surgery is type of minimally invasive surgery which is being widely adopted. Skills required for performing laparoscopic surgeries are different than open surgeries. Hence, it is critical to ensure that adequate training and assessment is provided to surgeons. Eye-gaze tracking technology has made it possible to compute metrics that could be employed for skill assessment. These metrics are based on involuntary gaze behaviors and are independent of the nature of the surgical training task being performed. Hence, they may not be suitable for feedback during training. Metrics suitable for feedback are context dependent metrics which take into account the task based information. Experts tend to show look-ahead behavior while performing a task which can be quantified using context dependent metrics. This research presents a three stage methodology which facilitates computation of context dependent metrics and feed-forward metrics enabling identification of different skill levels in trainees. Applying this methodology to dataset of nine trainees with 499 practice trials, a total of six metrics were computed and a classification model was built to predict three identified skill level with 99% accuracy. This research is directly applicable to developing an automated system for laparoscopic training and assessment.

Training improves skills in minimally invasive surgery. This study aimed to investigate the learning curves of complex motion parameters for both hands during a standardized training course using a novel measurement tool. An additional focus was placed on the parameters representing surgical safety and precision. Fifty-six laparoscopic novices participated in a training course on the basic skills of minimally invasive surgery based on a modified Fundamentals of Laparoscopic Surgery (FLS) curriculum. Before, twice during, and once after the practical lessons, all participants had to perform four laparoscopic tasks (peg transfer, precision cut, balloon resection, and laparoscopic suture and knot), which were recorded and analyzed using an instrument motion analysis system. Participants significantly improved the time per task for all four tasks (all p < 0.001). The individual instrument path length decreased significantly for the dominant and non-dominant hands in all four tasks. Similarly, both hands became significantly faster in all tasks, with the exception of the non-dominant hand in the precision cut task. In terms of relative idle time, only in the peg transfer task did both hands improve significantly, while in the precision cut task, only the dominant hand performed better. In contrast, the motion volume of both hands combined was reduced in only one task (precision cut, p = 0.01), whereas no significant improvement in the relative time of instruments being out of view was observed. FLS-based skills training increases motion efficiency primarily by increasing speed and reducing idle time and path length. Parameters relevant for surgical safety and precision (motion volume and relative time of instruments being out of view) are minimally affected by short-term training. Consequently, surgical training should also focus on safety and precision-related parameters, and assessment of these parameters should be incorporated into basic skill training accordingly.

Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Uterine manipulation is integral to obtaining adequate access to the uterus during a laparoscopic procedure. A variety of mechanical manipulators have been developed to aid the surgeon with the dissection of the uterus during laparoscopic hysterectomies. Limitations of existing manipulators are that they require an additional assistant during surgery, are expensive and may cause tissue trauma to the vaginal or cervical canal. This study introduces the novel concept of a magnetic uterine manipulator, intended to overcome existing devices’ shortcomings and enabling non-invasive uterine manipulation. The first goal of the study was to investigate the strengths and weaknesses of existing mechanical manipulators and compare them to those of a magnetic device. Analysis showed that a magnetic manipulator would not be able to compete in terms of the range of motion of existing devices. A limited anteriorsagittal rotation range of 60 was seen in the magnetic manipulator compared to a range of 140 in mechanical devices. However, the magnetic manipulator could eliminate the need for an extra assistant, is reusable and thus also more economical. The second goal was to investigate which type of setup would be most successful at effective uterine manipulation. Through concept analysis a cart-on-arch system was deemed most effective. To lift an effective load of 1 N over an air-gap of 150 mm rare-earth N38 Neodymium (NdFeBr) magnets showed the most promise as magnetic actuators. FEA (Finite Element Analysis) simulations of the magnetic setup were validated experimentally which produced an acceptable MAE (mean absolute error) of 0.15 N. Furthermore, a comparative simulation study of shielded and unshielded magnets was done which concluded that shielded magnets produce a slightly higher attraction force and would be safer to use due to less magnetic flux fringing. Thirdly and lastly, potential safety hazards and risks of using magnetic actuators in surgical environments were identified. The literature research revealed that connections between magnetic fields and health risks to patients have not been conclusively proven in clinical studies to date, but nonetheless, great care should be taken in situations where the patient has a pace-maker or orthopaedic implants, as these might interact with the magnetic field. Recommendations for future work include further research into the geometry and scaling effects of magnetic shielding as well as electromagnetic actuator design. Electromagnetic actuators could replace rare-earth magnets, if coil and cooling systems are optimized, resulting in magnets that can be reversed or switched off and which are therefore easier to control and safer to handle. / AFRIKAANSE OPSOMMING: Ontwikkeling van ’n Magnetiese Intra-Uteriene Manipuleerder Baarmoedermanipulasie is van uiterste belang om sodoende voldoende toegang te kry tot die baarmoeder gedurende ’n laparoskopiese prosedure. Daar is reeds ’n verskeidenheid meganiese manipuleerders ontwikkel as hulpmiddel vir die chirurg in die ontleding van die uterus tydens laparoskopiese histerektomies. Beperkings van bestaande manipuleerders is dat ’n bykomende assistent tydens chirurgie benodig word. Die manipuleerders is ook duur en kan weefseltrauma veroorsaak aan die vaginale of servikale kanale. Die studie stel ’n nuwe konsep bekend: ’n magnetiese baarmoedermanipuleerder, gemik daarop om bestaande toestelle se tekortkominge te oorkom en nie-indringende baarmoedermanipulasie moontlik te maak. Die eerste doel van die studie was om die voordele en nadele van bestaande meganiese manipuleerders te ondersoek en dit te vergelyk met dié van die magnetiese toestel. Analise het getoon dat ’n magnetiese manipuleerder nie met bestaande toestelle sal kan kompeteer waar dit gaan om beweegruimte nie. Daar is ’n beperkte anterior-sagitale rotasiespeling van 60 in die magnetiese manipuleerder, terwyl die meganiese toestel ’n rotasiespeling van 140 het. Die magnetiese manipuleerder kan egter die nodigheid van ’n bykomende assistant uitskakel, is herbruikbaar en dus ook meer ekonomies. Die tweede doel van die studie was om die tipe opstelling wat meer suksesvol sal wees tydens doeltreffende baarmoeder manipulasie te ondersoek. Konsep-analise het getoon dat ’n "cart-on-arch"stelsel die beste sal werk. N38 Neodimium (NdFeBr) magnete het die beste vertoon as magnetiese aandrywer om ’n werklike belasting van 1 N oor ’n lugspasie van 150 mm te lig. EEA (Eindige Element Analise) simulasies van die magnetiese opstelling is eksperimenteel bekragtig en het ’n aanvaarbare gemene absolute fout (GAF) van 0.15 N gelewer. ’n Vergelykende simulasie studie het verder gewys dat beskutte magnete ’n effens hoër aantrekkingskrag oplewer en sal dus veiliger wees om te gebruik vanweë die verminderde magnetiese stromingsrand. Derdens en laastens is potensiële veiligheidsrisikos en gevare in die gebruik van magnetiese drywers in chirurgiese omgewings geïdentifiseer. Literatuurnavorsing het onthul dat die verband tussen magneetvelde en gesondheidsrisikos aan pasiënte nog nie voldoende bewys is in kliniese studies tot op datum nie. Gevalle waar pasiënte ’n pasaangeër of ortopediese inplantings het moet met groot sorg hanteer word aangesien dit dalk kan reageer met die magneetvelde. Aanbevelings vir toekomstige werk sluit verdere navorsing in in die rigting van die geometrie en die afskilferingseffek van magnetiese beskutting en ook elektromagnetiese drywer ontwerp. Elektromagnetiese drywers kan moontlik rou aarde magnete vervang indien winding en afkoelstelsels ge-optimeer word wat kan lei tot magnete wat omgekeer of afgeskakel kan word en dus makliker beheerbaar is en veiliger om te hanteer.

Η γαστρική παράκαμψη κατά Roux en Y αποτελεί την πλέον δημοφιλή επέμβαση αντιμετώπισης της νοσογόνου παχυσαρκίας. Στη σύγχρονη εποχή, πάνω από τις μισές επεμβάσεις γαστρικής παράκαμψης διενεργούνται λαπαροσκοπικά. Σκοπός της παρούσας μελέτης είναι η σύγκριση μεταξύ της ανοικτής και της λαπαροσκοπικής τεχνικής, σε χρονικό ορίζοντα παρακολούθησης 5 ετών από την επέμβαση. Μέθοδος: Οι πρώτοι 60 ασθενείς, που υποβλήθηκαν σε ανοικτή γαστρική παράκαμψη και οι αντίστοιχοι 60 ασθενείς, που υποβλήθηκαν σε λαπαροσκοπική επέμβαση, μελετήθηκαν για 5 χρόνια μετεγχειρητικά. Οι παράμετροι, που καταγράφηκαν περιελάμβαναν την απώλεια βάρους και τη διατήρηση αυτής, τη βελτίωση ή πλήρη ίαση των συνοδών της παχυσαρκίας νόσων, τις πρώιμες και όψιμες μετεγχειρητικές επιπλοκές, τη διάρκεια επέμβασης και το χρόνο νοσηλείας των ασθενών. Αποτελέσματα: Όλοι οι ασθενείς παρουσίασαν απώλεια βάρους, χωρίς να παρατηρούνται στατιστικά σημαντικές διαφορές μεταξύ των δύο ομάδων, που διατηρήθηκε σε όλη τη διάρκεια του follow-up. Μικρή επανάκτηση του απολεσθέντος βάρους παρατηρήθηκε μετά τον 3ο χρόνο μετεγχειρητικά. Η ίαση ή βελτίωση των συνοδών νοσημάτων δεν παρουσίασε στατιστικά σημαντική διαφορά μεταξύ των δύο ομάδων. Ισοδύναμες παρουσιάζονται και οι δύο τεχνικές, όσον αφορά στην εμφάνιση μετεγχειρητικών επιπλοκών. Η διάρκεια της λαπαροσκοπικής επέμβασης παρουσιάζεται μεγαλύτερη, γεγονός που μπορεί να ερμηνευθεί βάσει της καμπύλης εκμάθησης. Η διάρκεια νοσηλείας δεν παρουσιάζει διαφορά μεταξύ των δύο ομάδων. Συμπεράσματα: Η λαπαροσκοπική γαστρική παράκαμψη, συγκρινόμενη με την ανοικτή επέμβαση, αποτελεί μία εξίσου ασφαλή και αποτελεσματική τεχνική για την αντιμετώπιση της κλινικά σοβαρής παχυσαρκίας. / Roux en Y gastric bypass (RYGBP) is the most popular operation between patients, undergoing bariatric operation. In modern times, over half of the gastric bypass operations are performed by the laparoscopic way. The aim of the present study is the comparison between open and laparoscopic technique, in a follow-up period of 5 years post surgically.`Methods: The first 60 patients, who underwent open gastric bypass and the respective 60 patients, who underwent the laparoscopic approach, were studied for 5 years post surgically. The parameters recorded, included the excess weight loss and the following maintenance of the loss, the improvement or healing of the obesity related comorbidities, early and late complications, the duration of the operation and the duration of the patients’ hospitalization. Results: All patients exhibited excess weight loss, without statistically significant differences between the two groups, which maintained throughout the follow-up period. A small proportion of regaining the lost weight was observed after the 3rd year post surgically. Healing or improvement of the obesity related comorbidities didn’t appear statistically significant difference between the two groups. There were no differences between the two groups regarding the post surgically complications. The duration of the laparoscopic approach was longer, which can be attributed to the learning curve. The duration of the patients’ hospitalization didn’t differ between the two groups. Conclusion: Laparoscopic gastric bypass, compared to the open procedure, is an equally safe and effective technique for the confrontation of clinically severe obesity.

Minimally Invasive Surgery (MIS) differs from Open Surgery as surgeons view the surgical site indirectly on a monitor. The view shown is typically from an angled endoscope off to one side of the surgery (i.e., uncollocated with the view of the hands). This makes camera navigation a challenging ability to learn. MIS thus requires longer training periods, more practice and mental effort to achieve proficiency. Current training setups and Operating Room (OR) environments lack appropriate real-time visual cues for navigation and other perception related information that could help with learning and performance in the OR. The purpose of this research was to design and develop graphical aids for improving understanding of camera navigation and depth perception in a trainer box necessary for enhancing surgeon’s skills to perform endoscopic surgery. For the former, two alternate training methods: 1) using no graphics (control group) and 2) using three different types of graphics conveying different information, were considered for this study. The effectiveness of the training was evaluated by a comparative analysis of different performance measures across all the groups. It was observed that training using graphics did improve the performance of participants in performing a minimally invasive surgery training task. For the latter, the use of a proximity sensor was explored.

The purpose of this experiment was to determine if there existed techniques to more efficiently train prospective surgeons the skills necessary to capably perform minimally invasive surgical procedures. Also, we wanted to know if trainees could be pushed to cognitively define a laparoscopic environment with a novel hand-eye relationship. To explore these questions, a simulation was setup wherein subjects would perform a laparoscopic transfer task and receive active feedback during training. Different subjects would receive different metrics as feedback and a comparison would be made between subjects with respect to standard metrics. Results of this experiment show that all subjects adapt to a laparoscopic environment and that they do so at different rates and to different proficiencies. The difference was shown to be statistically significant. It was concluded that the techniques we utilized were effective enough to claim as useful techniques to utilize in current training systems.

A infecção de sítio cirúrgico (ISC) é uma complicação que pode acometer o paciente, acarretando incremento da mortalidade e morbidade, bem como aumento dos custos em saúde. A videocirurgia surgiu como opção menos invasiva de acesso à cavidade abdominal, reduzindo as taxas de ISC, mas nem mesmo a modernização gerada pela cirurgia minimamente invasiva conseguiu extinguir esse tipo de infecção. O presente estudo teve como objetivo geral analisar a ocorrência e os fatores de risco de infecção de sítio cirúrgico, em pacientes submetidos à colecistectomia videolaparoscópica. Trata-se de estudo descritivo exploratório conduzido em hospital de pequeno porte, localizado no sudoeste de Minas Gerais. A amostra foi composta por 118 pacientes. Para a coleta de dados, elaborou-se instrumento, o qual foi submetido à validação de face e conteúdo por estudiosos da área de conhecimento de enfermagem perioperatória. A coleta dos dados foi realizada no período de março a novembro de 2016 e, em três momentos, a saber: perioperatório, retorno ambulatorial e busca ativa fonada. Os dados foram coletados pelo pesquisador e um auxiliar de pesquisa devidamente treinados. A ocorrência de ISC foi de 5,9% (n=7), sendo todos os casos diagnosticados como infecção incisional superficial. As variáveis investigadas relacionadas ao paciente foram sexo, faixa etária, Índice de Massa Corporal, presença de doença crônica e classificação ASA. As variáveis estudadas relacionadas ao procedimento anestésico-cirúrgico foram tempo total de internação, porte cirúrgico, tempo de anestesia e tempo de cirurgia. Os resultados não apresentaram diferença estatisticamente entre as variáveis de interesse e a presença de ISC. Todos os casos de ISC foram diagnosticados, após a alta hospitalar, desses, seis pacientes (86%) tiveram o diagnóstico no retorno ambulatorial, e um paciente (14%) foi diagnosticado durante a busca ativa fonada. A condução do estudo oferece subsídios para a compreensão da problemática, no âmbito nacional. Além disso, gerou evidências para a reflexão dos profissionais de saúde em relação à subnotificação desse tipo de infecção em cirurgia minimamente invasiva, reforçando a necessidade de implantação de programa de vigilância pós-alta, nos serviços de saúde / Surgical site infection (SSI) is a complication that can affect the patient, leading to an increase in mortality and morbidity, as well as an increase in health costs. Video surgery emerged as a less invasive option for access to the abdominal cavity, reducing SSI rates; however, not even the improvement generated by minimally invasive surgery was enough to eliminate this type of infection. This study aimed to analyze the occurrence and risk factors of surgical site infection in patients submitted to laparoscopic cholecystectomy. It is an exploratory-descriptive study conducted in a small hospital, located in the southwest of Minas Gerais. The sample consisted of 118 patients. An instrument was developed for data collection, which was submitted to face and content validation by experts in perioperative nursing. Data collection was performed from March to November 2016 and, in three stages: perioperative, outpatient return and active phone search. Data were collected by the researcher and a properly trained research assistant. The occurrence of SSI was 5.9% (n=7), being all cases diagnosed as superficial incisional infection. The studied variables related to the patient were gender, age, Body Mass Index, presence of chronic disease and ASA classification. The studied variables related to the anesthetic surgical procedure were total length of hospitalization, surgical procedure size, time of anesthesia and time of surgery. The results did not show statistically difference between the variables of interest and the presence of SSI. All cases of SSI were diagnosed after patient discharge, and among them, six patients (86%) were diagnosed during outpatient return, and one patient (14%) was diagnosed during the active phone search. This study offers subsidies for understanding the problem at national level. In addition, it generated evidence for the reflection of health professionals regarding the underreporting of this type of infection in minimally invasive surgery, reinforcing the need to implement a post-discharge surveillance program in health services

INTRODUÇÃO: O câncer da vesícula biliar é a lesão maligna mais comum da árvore biliar e pouco se sabe sobre a sua carcinogênese. O possível caráter pré-neoplásico das alterações histológicas da vesícula biliar vem sendo estudado recentemente. O objetivo deste estudo foi identificar e quantificar as alterações histológicas da vesícula biliar no nosso meio e correlacioná-las com dados clínicos, e correlacionar as alterações metaplásicas, em separado, com as demais alterações encontradas. MÉTODOS: Neste estudo retrospectivo realizado entre novembro de 1999 a dezembro de 2006, foram avaliados 1.689 prontuários de doentes submetidos a colecistectomia laparoscópica por colecistolitíase. Os doentes foram divididos em relação à idade em doentes com até 60 anos e com mais de 60 anos. Em relação ao tempo de sintomas antes da cirurgia foram agrupados em doentes sem sintomas, doentes com sintomas até 1 ano, e doentes com sintomas por mais de 1 ano antes da cirurgia. Em relação ao tamanho e número dos cálculos foram agrupados em doentes com cálculos de até 10 mm, e aqueles com cálculos maiores que 10 mm, e em doentes com cálculos únicos ou múltiplos. RESULTADOS: Eram mulheres 1.238 doentes (73,3%) e 451 eram homens (26,7%). Apresentaram idade de até 60 anos 1.192 doentes (70,6%) e 497 (29,4%) apresentaram mais de 60 anos. Apresentaram cálculos menores que 10 mm 1.319 doentes (78,1%) e 370 doentes (21,9%) apresentaram cálculos maiores que 10 mm. Foi observado inflamação aguda em 174 doentes (10,3%), gangrena em 23 (1,4%), abscesso em 8 (0,4%), colesterolose em 305 (18,1%), adenomiomatose em 40 (2,4%), colecistite xantogranulomatosa em 29 (1,7%), fibrose em 12 (0,7%), escleroatrofia em 20 (1,2%), pólipo hiperplásico em 3 (0,2%), pólipo de colesterol em 17 (1,0%), metaplasia pilórica em 72 (4,3%), metaplasia intestinal em 18 (1,1%), displasia em 4 (0,2%), câncer em 2 (0,1%). Não foram observados pólipos adenomatosos. CONCLUSÕES: O sexo masculino apresenta maior freqüência de complicações inflamatórias que o feminino. Não há relação entre o tempo de sintomas e uma maior ocorrência das alterações histológicas estudadas, excetuando-se a colecistite xantogranulomatosa. Nos doentes idosos há maior ocorrência de adenomiomatose, gangrena e abscesso. Há aumento progressivo de idade para a ocorrência de metaplasia pilórica, metaplasia intestinal, displasia e câncer. O tamanho dos cálculos não guarda relação com a ocorrência das alterações estudadas, exceto para colecistite aguda que se associou com cálculos pequenos e múltiplos. Há associação entre a ocorrência de metaplasia pilórica e adenomiomatose, metaplasia pilórica e displasia, metaplasia pilórica e câncer. Há também associação entre a ocorrência de metaplasia intestinal e metaplasia pilórica, metaplasia intestinal e adenomiomatose, metaplasia intestinal e displasia, metaplasia intestinal e câncer. / INTRODUCTION: Gallbladder cancer is the most common malignant lesion of the biliary tree; yet, little is known about its carcinogenesis. The possible preneoplastic character of histological gallbladder alterations has been studied in recent medical literature. The purpose of this study was to identify and quantify histological gallbladder alterations in our population, to correlate them with clinical data, and to correlate the metaplastic alterations, separately, with the other histological alterations found. METHODS: In this retrospective study conducted between November,1999 and December, 2006, the medical records of 1.689 patients who were submitted to laparoscopic cholecystectomy by cholecystolithiasis were analyzed. The patients were classified according to age: 60 years or younger, and older than 60. In relation to the duration of symptoms before the surgery, they were grouped according to: patients without symptoms, patients with symptoms for 1 year or less, and patients with symptoms for over 1 year before the surgery. In relation to the size and number of the gallstones, they were grouped according to: patients with gallstones of 10 mm or less, and those with gallstones over 10 mm, and those with single or multiple gallstones. RESULTS: There were 1,238 (73.3%) female and 451 (26.7%) male patients. In relation to age, 1,192 patients were 60 or younger (70.6%) and 497 (29.4%) were older than 60. There were 1.319 (78.1%) patients with gallstones smaller than 10 mm and 370 patients (21.9%) with gallstones larger than 10mm. Acute choelcystitis was observed in 174 patients (10.3%), gangrene in 23 (1.4%), abscess in 8 (0.4%), cholesterolosis in 305 (18.1%), adenomyomatosis in 40 (2.4%), xanthogranulomatous cholecystitis in 29 (1.7%), fibrosis in 12 (0.7%), sclero-atrophic gallbladder in 20 (1.2%), hyperplasic polyp in 3 (0.2%), cholesterol polyp in 17 (1.0%), pyloric metaplasia in 72 (4.3%), intestinal metaplasia in 18 (1.1%), dysplasia in 4 (0.2%), and cancer in 2 (0.1%). No adenomatous polyp was found. CONCLUSIONS: Male patients have more inflammatory complications than females. With the exception of xanthogranulomatous cholecystitis, there is no correlation between symptom duration and an increased occurrence of the histological alterations studied. In the elderly patients, the occurrence of adenomyomatosis, gangrene and abscess is more frequent. The size of gallstones has no relationship with the occurrence of the histological alterations studied, except for acute cholecystitis, which is associated with small and multiple gallstones. There is an association between pyloric metaplasia and the following: adenomyomatosis, dysplasia, and cancer. There is also an association between intestinal metaplasia and the following: pyloric metaplasia, adenomyomatosis, dysplasia, and cancer.