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Directed acyclic graphs (DAGs) are useful tools for visualizing the hypothesized causal structures in an intuitive way and selecting relevant confounders in causal inference. However, in spite of their increasing use in clinical and surgical research, the causal graphs might also be misused by a lack of understanding of the central principles. In this article, we aim to introduce the basic terminology and fundamental rules of DAGs, and DAGitty, a user-friendly program that easily displays DAGs. Specifically, we describe how to determine variables that should or should not be adjusted based on the backdoor criterion with examples. In addition, the occurrence of the various types of biases is discussed with caveats, including the problem caused by the traditional approach using p-values for confounder selection. Moreover, a detailed guide to DAGitty is provided with practical examples regarding minimally invasive surgery. Essentially, the primary benefit of DAGs is to aid researchers in clarifying the research questions and the corresponding designs based on the domain knowledge. With these strengths, we propose that the use of DAGs may contribute to rigorous research designs, and lead to transparency and reproducibility in research on minimally invasive surgery.

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Purpose: Laparoscopic surgery is a choice in several emergency settings. However, there has been no nationwide study or survey that has compared the clinical use of laparoscopic emergency surgery (LES) versus open abdominal emergency surgery (OES) in Korea. Therefore, we examined the state of LES across multiple centers in Korea and further compared this data with the global state based on published reports.
Methods: Data of 2,122 patients who received abdominal emergency surgery between 2014 and 2019 in three hospitals in Korea were collected and retrospectively analyzed. Several clinical factors were investigated and analyzed.
Results: Of the patients, 1,280 (60.3%) were in the OES group and 842 (39.7%) were in the LES group. The most commonly operated organ in OES was the small bowel (25.8%), whereas that for LES was the appendix. In appendectomy and cholecystectomy, 93.7% and 88.0% were in the LES group. In small bowel surgery, gastric surgery, and large bowel surgery, 89.4%, 92.0%, and 79.1% were in the OES group. The severity-related factors of patient status demonstrated statistically significant limiting factors of selection between LES and OES.
Conclusion: Although our study has several limitations, compared to the LES data from other countries, the general LES state was similar in appendectomies, cholecystectomies, and small bowel surgeries. However, in gastric and colorectal surgeries, the LES state was different from those of other countries. This study demonstrated the LES state and limiting factors of selection between LES and OES in various operated organs. Further studies are required to analyze these differences and the various limiting factors.

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Purpose: Minimally invasive surgery (MIS) offers patients several benefits, such as smaller incisions, and fast recovery times. General surgery residents should be trained in both open and MIS. We aimed to examine the trends of minimally invasive and open procedures performed by general surgery residents in Thailand.
Methods: A retrospective review of the Royal College of Surgeons of Thailand and Accreditation Council for Graduate Medical Education general surgery case logs from 2007 to 2018 was performed for common open and laparoscopic general surgery operations. The data were grouped by three time periods, which were 2007–2010, 2011–2014, and 2015–2018, and analyzed to explore changes in the operative trends.
Results: For Thai residents, the mean number of laparoscopic operations per person per year increased from 5.97 to 9.36 (56.78% increase) and open increased from 20.02 to 27.16 (35.67% increase). There was a significant increase in the average number of minimally invasive procedures performed among cholecystectomy (5.83, 6.57, 8.10; p < 0.001) and inguinal hernia repair (0.33, 0.35, 0.66; p < 0.001). Compared to general surgery residents in the United States, Thai residents had more experience with open appendectomy, but significantly less experience with all other operations/procedures.
Conclusion: The number of open and minimally invasive procedures performed or assisted by Thai general surgery residents has slowly increased, but generally lags behind residents in the United States. The Thai education program must be updated to improve residents’ technical skills in open and laparoscopic surgery to remain competitive with their global partners.

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Purpose: Robotic hernia repair has increased in popularity since the introduction of da Vinci robots (Intuitive Surgical). However, we lack quantitative analyses of its potential benefits. Herein, we report our initial experience with robotic transabdominal preperitoneal (R-TAPP) inguinal hernia repair.
Methods: We retrospectively reviewed the data from patients who underwent R-TAPP inguinal hernia repair with a prosthetic mesh using the da Vinci platform. Data on patient characteristics and surgical outcomes were also collected.
Results: Twenty-one patients (including 20 male patients [95.2%]) with a mean age of 54.1 ±16.4 years and body mass index of 23.8 ± 1.9 kg/m² underwent R-TAPP inguinal hernia repair. Bilateral hernia repair was performed in two patients (9.5%), and six patients (28.5%) with scrotal hernia underwent R-TAPP hernia repair. A sigmoid colon sliding hernia was present in three patients (14.3%). The mean operation and console times were 91.8 ± 20.4 minutes and 154.5 ± 26.2 minutes, and 61.4 ± 16.9 minutes and 128.0 ± 25.5 minutes for unilateral and bilateral inguinal hernia, respectively. Spermatic vessel injury was identified intraoperatively in one patient. Two minor postoperative complications, postoperative ileus, and wound seroma were reported. The mean duration of hospitalization was 3.8 ± 0.9 days. No recurrence or conversion to open surgery was required.
Conclusion: Our findings suggest that R-TAPP inguinal hernia repair is safe and feasible. Its cost-effectiveness, optimal procedural steps, and indications for a robotic approach require further investigation.

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Purpose: The robotic approach offers improved visualization and maneuverability for surgeons. This systematic review aims to compare the outcomes of robotic-assisted and conventional laparoscopic approaches for paraesophageal hernia repair, specifically examining postoperative complications, operative time, hospital stay, and recurrence.
Methods: A systematic review including thorough research through PubMed, Scopus, and Cochrane, was performed and only comparative studies were included. Studies concerning other types of hiatal hernias or children were excluded. A meta-analysis was conducted to compare overall postoperative complications, hospital stay, and operation time.
Results: Ten comparative studies, with 186,259 participants in total, were included in the meta-analysis, but unfortunately, not all of them reported all the outcomes under question. It appeared that there is no statistically significant difference between the conventional laparoscopic and the robotic-assisted approach, regarding the overall postoperative complication rate (odds ratio [OR], 0.56, 95% confidence interval [CI], 0.28–1.11), the mean operation time (t = 1.41; 95% CI, –0.15–0.52; p = 0.22), and the hospital length of stay (t = –1.54; degree of freedom = 8; 95% CI, –0.53–0.11; p = 0.16). Only two studies reported evidence concerning the recurrence rates.
Conclusion: Overall, the robotic-assisted method did not demonstrate superiority over conventional laparoscopic paraesophageal hiatal hernia repair in terms of postoperative complications, operation time, or hospital stay. However, some studies focused on cost and patient characteristics of each group. Further comparative and randomized control studies with longer follow-up periods are needed for more accurate conclusions on short- and long-term outcomes.

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Endometriosis is a benign gynecological disease characterized by the presence of endometrial tissue outside the uterus. The eradication of non-gynecological localizations represents the real surgical challenge. A 29-year-old woman underwent robotic surgery with the Da Vinci system (Intuitive Surgical Inc.) for a diagnosis of stage IV deep endometriosis. The patient presented with 5 cm left ovarian endometrioma, an infiltration of the left posterior parametrium, and bilateral ureteral endometriosis. Once inside the pelvic cavity, deep intestinal infiltrating endometriosis implants were confirmed as triple, multicentric, and multifocal lesions, affected distal sigmoid, rectosigmoid junction, and upper rectum. An expert multiple excision, sparing the intestinal mucosa, was performed. To our knowledge, this is the first description of a multiple robotic shaving of multicentric endometriotic intestinal lesions. After the surgery, a normal diet was quickly restored, accelerating the recovery of the physiological peristalsis and the overall recovery time.

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Hepaticojejunostomy is currently the best treatment for post-cholecystectomy biliary strictures. Laparoscopic repair has not gained popularity due to difficult reconstruction. We present case of 43-year-old-female with Bismuth type 2 stricture following laparoscopic converted open cholecystectomy with bile duct injury done elsewhere. Position was modified Llyod-Davis position and four 8-mm robotic ports (including camera) and 12-mm assistant port were placed. The procedure included noticeable steps such as adhesiolysis, identification of gallbladder fossa, identification of common hepatic duct, lowering of hilar plate etc. Operating and console time were 420 and 350 minutes and blood loss was 100 mL. Patient was discharged on postoperative day 4. Robotic repair (hepaticojejunostomy) of biliary tract stricture after cholecystectomy is safe and feasible with good outcomes.

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Robotic central pancreatectomy has not been widely performed because of its rare indications, technical difficulties, and concern about the high complication rate. We reviewed six robotic central pancreatectomy cases between May 2016 and June 2021 at a single institution. This multimedia article aims to introduce our technique of robotic central pancreatectomy with perioperative and follow-up outcomes. All patients experienced biochemical leakage of postoperative pancreatic fistula, except in one with a grade B pancreatic fistula, which resulted in a pseudocyst formation and was successfully managed by endoscopic internal drainage. All patients achieved completely negative resection margins. There was no new-onset diabetes mellitus or recurrence during the median follow-up period of 13.5 months (range, 10–74 months). With an acceptable complication rate and the preservation of pancreatic function, robotic central pancreatectomy could be a good surgical option for patients with benign and borderline malignant tumors of the pancreatic neck or proximal body.