Gelatin-Based Liver Phantoms for Training Purposes: A Cookbook Approach.

Background: Patients with liver pathology benefit from image-guided interventions. Training for interventional procedures is recommended to be performed on liver phantoms until a basic proficiency is reached. In the last 40 years, several attempts have been made to develop materials to mimic the imaging characteristics of the human liver in order to create liver phantoms. There is still a lack of accessible, reproducible and cost-effective soft liver phantoms for image-guided procedure training. Methods: Starting from a CT-scan DICOM file, we created a 3D-printed liver mold using InVesalius (Centro de Tecnologia da informação Renato Archer CTI, InVesalius 3 open-source software, Campinas, Brazil) for segmentation, Autodesk Fusion 360 with Netfabb (Autodesk software company, Fusion 360 2.0.19426 with Autodesk Netfabb Premium 2023.0 64-Bit Edition, San Francisco, CA, USA) for 3D modeling and Stratasys Fortus 380 mc 3D printer (Stratasys 3D printing company, Fortus 380 mc 3D printer, Minneapolis, MN, USA). Using the 3D-printed mold, we created 14 gelatin-based liver phantoms with 14 different recipes, using water, cast sugar and dehydrated gelatin, 32% fat bovine milk cream with intravenous lipid solution and technical alcohol in different amounts. We tested all these phantoms as well as ex vivo pig liver and human normal, fatty and cirrhotic liver by measuring the elasticity, shear wave speed, ultrasound attenuation, CT-scan density, MRI signal intensity and fracture force. We assessed the results of the testing performed, as well as the optical appearance on ultrasound, CT and MRI, in order to find the best recipe for gelatin-based phantoms for image-guided procedure training. Results: After the assessment of all phantom recipes, we selected as the best recipe for transparent phantoms one with 14 g of gelatin/100 mL water and for opaque phantom, the recipes with 25% cream. Conclusions: These liver gelatin-based phantom recipes are an inexpensive, reproducible and accessible alternative for training in image-guided and diagnostic procedures and will meet most requirements for valuable training.

Residents Can Do It! A Training Program in Laparoscopic Liver Surgery for General Surgery Residents.

INTRODUCTION: Laparoscopic liver resections (LLRs) constitute an area of surgery that has been kept away from residents in their hands-on training. The aim of our study is to assess the feasibility and the value of a didactic "step-by-step" program for LLR performed by residents using the swine training model. METHODS: From May 2018 to November 2019, three hands-on workshops were held. The protocol involved the performance of cholecystectomy, liver mobilization, minor and major hepatectomies. The participants' performance results in terms of operative time, blood loss, conversion, trainers' intervention, and intraoperative mortality, were recorded. The first workshop was comprised of 30 residents who previously participated in laparoscopic surgery workshops. In the second workshop, after six residents dropped out due to residency completion, the findings for the remaining 24 residents were compared to those for 24 junior-attending surgeons who did not follow the protocol and had not performed LLR previously, and to another 24 residents in a third workshop, who had not taken the training program before but followed the protocol. RESULTS: All residents fully completed the surgical procedures. Trained residents achieved better operative times and less blood loss compared to junior-attending surgeons (p < 0.017), however, the remaining parameters were comparable. When compared to non-trained residents, those who underwent training achieved significantly better results only in operative times (p < 0.001). CONCLUSION: A continuous LLR "step-by-step" training program on swine for residents is feasible and the "step-by-step" protocol is a valuable tool for a proper surgical education.

Analysis of the MLH1, MLH2, MLH6, PMS2 genes and their correlations with clinical data in rectal mucinous adenocarcinoma.

BACKGROUND: Microsatellites are short repeated DNA sequences normally found in the human genome. Following specific mutations, microsatellites can vary in the number of repeats thus making the DNA unstable. Microsatellite instability (MSI) is responsible for approximately 20% of rectal cancers, while the remaining 80% are caused by chromosomal instability. One of the following genes, MLH1, MLH2, MLH 6, and PMS2, is inactivated, leading to MSI colorectal cancers. AIM: This study aimed to analyze the expression of some MMR system genes presenting mutations in mucinous rectal cancer and their correlations with clinical data. METHODS: A retrospective study was performed on patients with rectal mucinous adenocarcinoma who underwent surgery between January 2000 and January 2017. We collected a total of 42 patients and analyzed the demographic data, histopathological results and MMR system genes mentioned above. RESULTS: Almost 93% of the cases analyzed had MSI-H and only 7% were MSI-L. For MLH1, 50% of stage T2 and 50% of stage T4 had weak expression, while in stage T3, 42.50% had moderate expression. Regarding the N stage, we found that 66.67% of the patients with moderate gene expression (2+) were N2, while 42% of the patients with weak expression were N0. For MSH2, the majority of patients with strong gene expression were in stage T3 (27%). Weak expression was found in 50% of the patients in stage T2, 35% of the patients in stage T3, and 33.3% in T4. In 44.44% of the weak expression was N2, while for strong expression, there was an equivalent percentage of 33.33% in stages N1 and N2. Describing the MSH6 gene, we found that the most heterogeneous results were in stage T3. Weak expression was observed in 38.46% of the patients, while moderate and strong expression was observed in 30.77% and 11.54% respectively. Analysis of PMS2 revealed that 66.67% of the patients in stage T4 had a weak expression of the gene, while the same expression was found in 38.46% of the patients in stage T3. A total of 23.08% of patients in stage T3 had strong gene expression. We also analyzed the overall gene expression. Thus, we found that three patients (7.14%) had only 1, three genes were expressed, nine (21.42%) had two genes and the remaining 27 patients had all 4. The 1-year survival rate in the analyzed lot was 75%, decreasing to 60% in the second year and 35% in the 3rd. There were no statistically significant differences in survival data between the stages or gene expression. CONCLUSIONS: Our study showed no statistical difference regarding the survival on different gene expression or staging, consistent with studies that found that mucin expression does not have a significant impact on local recurrence, nor does it affect nodal down staging. KEY WORDS: Mucinous adenocarcinoma, Microsatelites instability.

How I do it: parastomal hernia repair and ventral post-incisional hernia repair using PCS/TAR A case report.

We present a medical case of a 61 year-old male patient who reported to the outpatient clinic with a parastomal hernia of 10 cm in diameter and a postincisional midline hernia of 15 cm in diameter. We emphasized that the patient had undergone surgery 4 years before for a rectal adenocarcinoma, in which we performed an abdominal perineal resection of the rectum with end colostomy. At the time of admission, there were no imagistic signs of local or distant relapse. The surgical technique used aimed to repair both of the abdominal defects by placing a large polypropylene mesh (30x30 cm) spanning into the retro-rectus space in a sublay position. On the colostomy side, the mesh is extended up to the median axillary line by performing TAR (transversus abdominis release), according to the technique described by Pauli, thus the colostomy side is not modified. The post-operatory evolution was favourable, with the return of intestinal transit for faeces and gas on the second post-operatory day. The patient was discharged on the 7th postoperatory day, after the suppression of the over-prosthetic drainage. KEY WORDS: Parastomal hernia, PCS/TAR.

The accuracy of endorectal ultrasonography and high-resolution magnetic resonance imaging for restaging rectal cancer after neoadjuvant chemoradiotherapy.

AIM: Endorectal ultrasonography (ERUS) and high-resolution Magnetic Resonance Imaging (HR-MRI) are two frequently used techniques for the preoperative staging of rectal cancer to offer proper neoadjuvant or surgical treatment. Because tumor restaging after neoadjuvant therapy using ERUS and HR-MRI remains challenging the aim of this study is to determine which of the two imaging methods used in restaging rectal cancer has the highest accuracy. MATERIAL AND METHODS: We included patients with rectal cancer who underwent ERUS and HR-MRI scans before and after neoadjuvant chemo-radiotherapy (n-CRT). The n-CRT was followed by imagistic restaging at 6 weeks after the last therapy session and by surgical resection. The pathology stage from the surgical sample was compared with the HR-MRI and ERUS restaging. RESULTS: Fifty-four patients underwent n-CRT and 47 were restaged by both ERUS and HR-MRI. ERUS was accurate in tumor restaging after n-CRT in 29 cases (61.7%) and HR-MRI in 32 cases (68%). Regarding lymphatic node status, ERUS was accurate for 34 patients (72.3%) and had an overall rate of over-staging of 12.8% and 14.9% of under-staging. HR-MRI was accurate for 30 patients (63.8%) in restaging the lymph nodes after n-CRT and had an overall rate of over-staging of 25.5% and 10.7% of under-staging. CONCLUSION: Restaging rectal cancer after n-CRT remains difficult because of radiotherapy tissue alteration, which results in low diagnostic accuracy for both methods. KEY WORDS: Endorectal Ultrasonography (ERUS), High-Resolution Magnetic Resonance Imaging (HR-MRI), Neoadjuvant Chemo-Radiotherapy, Rectal Cancer Restaging.

Malignant endometriosis of the abdominal wall.

Endometriosis is a disease represented by the presence of extra uterine endometrial tissue. It is a rare condition, and malignant transformation is seldom. We report a case with clear cell adenocarcinoma oncogenesis on abdominal wall scar that appeared after years of a caesarian section. After diagnosis, surgical treatment was performed twice, due to the fact that the margins were infiltrated with tumor cells, with replacement of the defect with a polypropylene mesh. The patient was cured and discharged with a favorable prognostic. To the best of our knowledge, there are few reported cases of clear cell adenocarcinoma arising from abdominal wall endometriosis. It is a rare condition that appears mostly after abdominal surgical interventions that clinicians must be aware. KEY WORDS: Abdominal wall, Endometriosis, Cesarean section, Clear cell adenocarcinoma, Malignant transformation.