Background/Aims: Colorectal polyp detection during colonoscopy is influenced by the lesion location, size, morphology, and histology. However, no studies have systematically assessed the difficulty of detection along the short axis of the intestinal lumen. This study aimed to evaluate the colorectal polyp detection rates on this axis during colonoscopy. Methods: This retrospective study analyzed 1,169 polyps in 513 patients who underwent colonoscopy at Showa University Hospital between November 2022 and February 2023. The short-axis lumen was divided into: upper right, lower right, lower left, and upper left. Each polyp detected was assigned to a quadrant. Detection rates were compared across quadrants and analyzed for associations with clinicopathological factors including lesion size, location, macroscopic type, and examiner experience. Results: The lesion detection rates varied significantly by quadrant. The upper left quadrant had the lowest detection rate (17.5%) compared with the expected 25.0% per quadrant. Subgroup analyses consistently confirmed the lower detection rates in this quadrant across most lesion types and patient groups, except for lesions in the cecum and rectum. Conclusions The lower detection rate in the upper left quadrant suggests that this orientation poses a challenge and may increase the number of missed lesions. Enhanced examination of this area may improve detection; however, further prospective studies are required.

Background: In recent years, dexmedetomidine (DEX) has been proposed as a useful vasoconstrictor for local anesthesia because it is less effective in circulation than clonidine of antihypertensive drugs. In addition, DEX is expected to act as a vasoconstrictor during local anesthesia. However, histomorphometric studies demonstrating that DEX exerts vasoconstrictive effects are lacking. This study aimed to clarify whether DEX exerts a histomorphologically vasoconstrictive effect on blood vessels in the mandible of rats. Methods: A total of 12 male Wistar rats were used. General anesthesia was induced and maintained using sevoflurane. Normal saline (0.2 ml) was injected on the left side of the jaw (DEX (-) effect site) and 0.2 ml normal saline containing 12.5 µg/ml DEX was injected on the right side of the jaw (DEX (+) effect site).The puncture point was located on the mesial side of the first molar, 1 mm away from the gingival sulcus.Following decalcification, the specimens were paraffinized and sagittally sliced into 20 μm-thick sections, followed by staining with anti-α smooth muscle actin antibody. The intravascular lumen area was measured in the oral mucosa, periodontal ligament, mandibular bone above the root apex, mandibular bone below the root apex, and dental pulp. The unpaired t-test was used for statistical analysis, and a P value < 0.05 was considered statistically significant. Results: Compared to the DEX (-) effect site, the intravascular lumen area in the oral mucosa and periodontal ligament of the DEX (+) effect site was significantly decreased. No significant difference was observed in the intravascular lumen area between the DEX (-) and DEX (-) effect sites in the mandibular bone above and below the root apex and dental pulp. Conclusion A direct vasoconstrictive effect of DEX was not observed in the intravascular lumen of the mandibular bone above and below the root apex and dental pulp; however, it was observed in the oral mucosa and periodontal ligament.

Background: In recent years, dexmedetomidine (DEX) has been proposed as a useful vasoconstrictor for local anesthesia because it is less effective in circulation than clonidine of antihypertensive drugs. In addition, DEX is expected to act as a vasoconstrictor during local anesthesia. However, histomorphometric studies demonstrating that DEX exerts vasoconstrictive effects are lacking. This study aimed to clarify whether DEX exerts a histomorphologically vasoconstrictive effect on blood vessels in the mandible of rats. Methods: A total of 12 male Wistar rats were used. General anesthesia was induced and maintained using sevoflurane. Normal saline (0.2 ml) was injected on the left side of the jaw (DEX (-) effect site) and 0.2 ml normal saline containing 12.5 µg/ml DEX was injected on the right side of the jaw (DEX (+) effect site).The puncture point was located on the mesial side of the first molar, 1 mm away from the gingival sulcus.Following decalcification, the specimens were paraffinized and sagittally sliced into 20 μm-thick sections, followed by staining with anti-α smooth muscle actin antibody. The intravascular lumen area was measured in the oral mucosa, periodontal ligament, mandibular bone above the root apex, mandibular bone below the root apex, and dental pulp. The unpaired t-test was used for statistical analysis, and a P value < 0.05 was considered statistically significant. Results: Compared to the DEX (-) effect site, the intravascular lumen area in the oral mucosa and periodontal ligament of the DEX (+) effect site was significantly decreased. No significant difference was observed in the intravascular lumen area between the DEX (-) and DEX (-) effect sites in the mandibular bone above and below the root apex and dental pulp. Conclusion A direct vasoconstrictive effect of DEX was not observed in the intravascular lumen of the mandibular bone above and below the root apex and dental pulp; however, it was observed in the oral mucosa and periodontal ligament.

Background: In recent years, dexmedetomidine (DEX) has been proposed as a useful vasoconstrictor for local anesthesia because it is less effective in circulation than clonidine of antihypertensive drugs. In addition, DEX is expected to act as a vasoconstrictor during local anesthesia. However, histomorphometric studies demonstrating that DEX exerts vasoconstrictive effects are lacking. This study aimed to clarify whether DEX exerts a histomorphologically vasoconstrictive effect on blood vessels in the mandible of rats. Methods: A total of 12 male Wistar rats were used. General anesthesia was induced and maintained using sevoflurane. Normal saline (0.2 ml) was injected on the left side of the jaw (DEX (-) effect site) and 0.2 ml normal saline containing 12.5 µg/ml DEX was injected on the right side of the jaw (DEX (+) effect site).The puncture point was located on the mesial side of the first molar, 1 mm away from the gingival sulcus.Following decalcification, the specimens were paraffinized and sagittally sliced into 20 μm-thick sections, followed by staining with anti-α smooth muscle actin antibody. The intravascular lumen area was measured in the oral mucosa, periodontal ligament, mandibular bone above the root apex, mandibular bone below the root apex, and dental pulp. The unpaired t-test was used for statistical analysis, and a P value < 0.05 was considered statistically significant. Results: Compared to the DEX (-) effect site, the intravascular lumen area in the oral mucosa and periodontal ligament of the DEX (+) effect site was significantly decreased. No significant difference was observed in the intravascular lumen area between the DEX (-) and DEX (-) effect sites in the mandibular bone above and below the root apex and dental pulp. Conclusion A direct vasoconstrictive effect of DEX was not observed in the intravascular lumen of the mandibular bone above and below the root apex and dental pulp; however, it was observed in the oral mucosa and periodontal ligament.

Background: We assessed the relationship between patient age and remifentanil dosing rate in patients managed under general anesthesia with spontaneous breathing using low-dose remifentanil in sevoflurane. Methods: The participants were patients with an American Society of Anesthesiologists Physical Status of 1 or 2 maintained under general anesthesia with low-dose remifentanil in 1.5-2.0% sevoflurane. The infusion rate of remifentanil was adjusted so that the spontaneous respiratory rate was half the rate prior to the induction of anesthesia, and γH 　(µg/kg/min) was defined as the infusion rate of remifentanil under stable conditions where the respiratory rate was half the rate prior to the induction of anesthesia for ≥ 15 minutes. The relationship between γH and patient age was analyzed statistically by Spearman's correlation analysis. Results: During dental treatment under general anesthesia using low-dose remifentanil in sevoflurane, a significant correlation was detected between γH and patient age. The regression line of y = − 0.00079 x + 0.066 (y-axis; γH , x-axis; patient's age) was provided. The values of γH provide 0.064 µg/kg/min at 2 years and 0.0186 µg/kg/min at 60 years. Therefore, as age increases, the dosing rate exhibits a declining trend. Furthermore, in the dosing rate of remifentanil when the patient's respiratory rate was reduced by half from the preanesthetic respiratory rate, the dosing rate provided was around 0.88 mL/h in all ages if the remifentanil was diluted as 0.1 mg/mL. EtCO2 showed 51.0 ± 5.7 mmHg, and SpO2 was controlled within the normal range by this method. In addition, all dental treatments were performed without major problems, such as awakening and body movement during general anesthesia, and the post-anesthetic recovery process was stable. Conclusion General anesthesia with spontaneous breathing provides various advantages, and the present method is appropriate for minimally invasive procedures.

Objective : The aim of this study is to describe a series of patients undergoing reoperation due to hemolytic anemia after mitral valve surgery and assess the mechanisms and surgical outcomes. Methods : Between 2009 and 2014, we performed redo mitral valve surgery in 11 patients who had refractory hemolytic anemia after mitral valve surgery at Kyoto University Hospital. The mean age of the patients was 72.2±6.8 years old, and there were 5 men. Results : Preoperative echocardiography demonstrated that only 3 patients had ≥ grade 3 mitral regurgitation (MR), the rest of the patients had only mild to moderate MR. The mechanisms of severe hemolysis included paravalvular leakage (PVL) after mitral valve replacement (MVR) in 8 patients, structural valve deterioration (SVD) after MVR using a bioprosthesis in one, and residual/recurrent mitral regurgitation after mitral valve plasty (MVP) in two. All the patients except one (re-MVP) underwent MVR. The mean interval between previous operation and current operation was 14.1±9.4 years in post-MVR cases, and 2.0±1.9 years in post-MVP cases. There were three late deaths, one of which was due to cardiac death (exacerbation of heart failure due to pneumonia). There was one patient who required re-MVR for recurrent hemolysis due to PVL after MVR. Conclusion : Although hemolytic anemia after mitral valve surgery is rare, it often requires reoperation regardless of the degree of MR at late follow-up period. Thus, patients after mitral valve surgery should be carefully followed-up.

Unroofed coronary sinus (URCS) is a rare cardiac anomaly, in which communication occurs between the coronary sinus (CS) and the left atrium (LA) because of partial or complete absence of the CS roof. A 30-year-old woman was scheduled for surgical closure of atrial septal defect, mitral valve repair and tricuspid annuloplasty. The intraoperative transesophageal echocardiography (TEE) revealed left-to-right shunt between the CS and the LA. The three-dimensional (3D) TEE confirmed the diagnosis of partially URCS. This defect was repaired with a pericardial patch. In this case, the 3D images of URCS, which were a helpful supplement to the 2D images, providing better visualization of the wall defect and more information regarding the size and location of the defect. The combined use of 2D and 3D images provides valuable information to aid in understanding the anatomy and morphology of this rare anomaly.
Adult ; Coronary Sinus* ; Diagnosis ; Echocardiography, Three-Dimensional ; Echocardiography, Transesophageal* ; Female ; Heart Atria ; Heart Defects, Congenital ; Heart Septal Defects, Atrial ; Humans ; Mitral Valve ; Vena Cava, Superior*