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Abstract Interseismic strain around southwest Japan can be attributed to slip phenomena on the plate interface and processes inside the continental plate, such as block motions and inland fault slips. Although many crustal deformation analyses have been carried out, the simultaneous estimation of these phenomena and comprehensive discussion regarding the effect on the total strain budget remain topics to be investigated. In this study, we conducted numerical experiment to evaluate the possibility of simultaneously monitoring the spatiotemporal evolution of interseismic fault slips and block motions based on state-space modeling. We aimed to estimate fault slips and block motions using the time series of dense continuous Global Navigation Satellite System sites covering southwest Japan, encompassing 25 years from 1996 onward. We calculated synthetic block motions of the forearc region, monotonically increasing back slips on block boundary faults, and long-term slow slip events in the Tokai region, Kii Channel, and Bungo Channel. Subsequently, we generated the expected synthetic displacement time-series at GNSS stations. Applying Kalman filtering, we successfully estimated the spatiotemporal evolution of block motions, cumulative back slips, multiple slow slip events occurring in different regions. Although the contributions of fault slips and block motions showed slight trade-off, main characteristics of the slip distributions and the direction of block motions were well-recovered. We recovered slow slip events with slips of 5–10 cm or larger. We investigated the estimation uncertainty and separation precision of the unknown parameters using the covariance matrix estimated by Kalman filtering. Focusing on the structure of the non-diagonal component of the covariance matrix, we evaluated the complex effects of site and subfault locations on the estimated slip spatial distribution bias. For instance, the extent of the correlation between subfaults suggested that the three slow slip regions have different tendency of the uncertainties of slip areas, extending toward landside, seaward, or both of them. Our framework enables the comprehensive evaluation of the contributions and uncertainties of various deformation sources covering the entire subduction zone. Graphical abstract

We, herein, report a surgical technique for laparoscopy-assisted jejunostomy tube placement in an infant using a loop needle device to fix the jejunum and abdominal wall. A 3-year-old boy with Down's syndrome underwent nutritional management by gastrostomy due to oral feeding difficulty after radical surgery for congenital duodenal stenosis and following bile duct stenosis. However, intractable gastrostomy site leakage emerged; hence, laparoscopy-assisted gastrostomy takedown and simultaneous laparoscopy-assisted jejunostomy tube placement were planned. After laparoscopy-assisted gastrostomy closure was performed, the jejunum was extracted through the umbilical trocar wound. A jejunostomy tube kit was inserted at the left side of the umbilicus. After tube insertion into the jejunum, the jejunostomy tube was wrapped with four interrupted sutures using the Witzel technique. Suture threads were extracted by percutaneous insertion of a loop needle device, and then, the jejunum was fixed to the abdominal wall. The post-operative course was uneventful. Percutaneous insertion of a loop needle device is useful for fixing a jejunostomy tube to the abdominal wall using the Witzel technique. Our technique is safe, secure and expected to reduce the risk of dislodgement of tube and peritonitis associated with jejunostomy tube placement.

Abstract Background The repair of large abdominal wall defects that cannot be closed primarily is quite challenging. The component separation technique (CST) is a surgical approach using autologous tissue to close large abdominal wall defects. The CST requires extensive dissection between the abdominal skin and the anterior sheath of the rectus abdominis muscle. Subsequently, incisions are made at both sides of the external oblique aponeurosis, releasing the external oblique muscle from the internal oblique muscle, and then the right and left rectus abdominis muscles are brought together in the midline for defect closure. However, impairment of blood flow in the abdominal wall skin and necrotic changes are recognized as potential complications. Case presentation The CST was performed in a 4-year-old boy with a large ventral hernia who had undergone skin closure with abdominal wall relaxing incisions for the primary treatment of giant omphalocele in the neonatal period. Given his history of incisions on the abdominal wall, he was speculated to be at high risk for postoperative skin ischemia. Dissection was therefore kept to a minimum to preserve the blood supply from the superior and inferior epigastric arteries and perforating branches of those arteries through the rectus abdominis muscle. In addition, care was taken to adjust the muscle relaxant dosage while monitoring the intravesical pressure, ensuring that it did not exceed 20 mmHg to avoid impaired circulation in the abdominal wall caused by abdominal compartment syndrome. He was discharged 23 days after the surgery without any complications, and neither recurrence of the ventral hernia nor bowel obstruction was observed in 4 years. Conclusions A giant omphalocele with primary skin closure was treated by applying the CST. The procedure can be performed safely while preserving the blood flow to the abdominal wall, even in patients with a history of relaxing incisions on the abdominal skin. The CST is expected to be effective for repairing the large abdominal wall defects seen in giant omphalocele when primary closure is not possible.

Abstract Background Reduction en masse (REM) is a rare condition following manual inguinal hernia (IH) reduction in which a hernia sac is reduced back into the preperitoneal space with a loop of the bowel incarcerated at the neck of the sac. It resembles successful manual reduction and may thus be overlooked easily. We herein report an infantile case of REM of an IH that was successfully treated laparoscopically. Case presentation A 10-month-old boy with a surgical history of bilateral open IH repair at 4 months old presented with a bulge in his left groin and vomiting. A left incarcerated recurrent IH was suspected, and manual reduction was performed. The hernia was apparently reduced successfully, but abdominal distention and vomiting persisted. He was admitted for further observation due to the symptoms. On day 2 after admission, abdominal X-ray showed extensive small bowel obstruction (SBO). Enhanced computed tomography (CT) revealed protrusion of the small bowel with a closed-loop in the left groin. A closed-loop SBO due to postoperative adhesion or an internal hernia was suspected. To assess the etiology of SBO, emergent laparoscopic exploration with hernia repair was planned. Laparoscopy revealed REM of the left incarcerated IH with a thickened peritoneum at the neck of the sac. Laparoscopic reduction was performed, and the incarcerated small bowel showed no signs of ischemia. The hernia sac was not associated with the previously ligated processes vaginalis, which had been closed by a previous Potts’ procedure. It was located at the inside of the processes vaginalis. The sac was successfully closed by laparoscopic percutaneous extraperitoneal closure procedures, and iliopubic tract repair was also performed via the previous inguinal incision. The postoperative course was uneventful. Conclusion Pediatric IH is due to the patent processes vaginalis, and REM is extremely rare. Laparoscopic surgery for REM is a relatively common and useful approach for the diagnosis and treatment of adults. In our infantile case, the laparoscopic approach was similarly effective for both investigating the cause of SBO and performing high ligation of the sac for this rare condition with IH.

Objective The present study attempts to clarify the clinical features of pediatric intra-abdominal solid organ injury at two institutions.Methods The injured organ, patient age, sex, injury grade, imaging findings, intervention, length of hospital stay, and complications were retrospectively reviewed using medical records at two centers from 2007 to 2021.Results There were 25 cases of liver injury, 9 of splenic injury, 8 of pancreatic injury, and 5 of renal injury. The mean age of all patients was 8.6±3.8 years old, with no difference between organ injury types. Radiological intervention was performed in four cases of liver injury (16.0%) and one case of splenic injury (11.1%), and surgery was performed in two cases of liver injury (8.0%) and three cases of pancreatic injury (37.5%). All other cases were treated conservatively. Complications included adhesive ileus in one case of liver injury (4.0%), splenic atrophy in one case of splenic injury (11.1%), pseudocysts in three cases of pancreatic injury (37.5%), atrophy of the pancreatic parenchyma in one case of pancreatic injury (12.5%), and urinoma in one case of renal injury (20.0%). No mortalities were observed.Conclusion Pediatric patients with blunt trauma had favorable outcomes at two pediatric trauma centers covering a broad medical area, including remote islands.

Abstract Background The mortality rate of esophageal atresia (EA) has significantly improved, but late complications remain problematic. We evaluated the physical growth, late complications, and social prognosis of postoperative patients with EA who have reached 15 years of age. Methods EA patients who were treated at our institution from 1984 to 2003 were enrolled. The follow-up, physical growth at the last visit, late complications and treatment, academic status, and employment situation were evaluated. Results Twenty-nine EA patients were registered, and the 23 surviving patients (79.3%) were followed. Anthropometry at the latest visit tended to be below the standard values. Fundoplication was performed in 6 (26.1%) of 9 (39.1%) patients with gastroesophageal reflux. Anastomotic stenosis was found in 12 patients (52.2%), and 2 (8.7%) were treated with re-anastomosis. Thirteen patients were attending a regular school, and one was attending a school for disabled children. Four had jobs from 18 years of age. Follow-up was aborted during early childhood in nine patients. Conclusions The physical size of EA was smaller than in the healthy population of the same age. Late complications had not affected the physical growth but were sometimes recognized in adolescence. The social prognosis of the patients was largely favorable.

Abstract We propose a local earthquake tomography method that applies a structured regularization technique to determine sharp changes in Earth’s seismic velocity structure using arrival time data of direct waves. Our approach focuses on the ability to better image two common features that are observed in Earth’s seismic velocity structure: sharp changes in velocities that correspond to material boundaries, such as the Conrad and Moho discontinuities; and gradual changes in velocity that are associated with pressure and temperature distributions in the crust and mantle. We employ different penalty terms in the vertical and horizontal directions to refine the earthquake tomography. We utilize a vertical-direction (depth) penalty that takes the form of the $${l}_{1}$$ l 1 -sum of the $${l}_{2}$$ l 2 -norms of the second-order differences of the horizontal units in the vertical direction. This penalty is intended to represent sharp velocity changes caused by discontinuities by creating a piecewise linear depth profile of seismic velocity. We set a horizontal-direction penalty term on the basis of the $${l}_{2}$$ l 2 -norm to express gradual velocity tendencies in the horizontal direction, which has been often used in conventional tomography methods. We use a synthetic data set to demonstrate that our method provides significant improvements over velocity structures estimated using conventional methods by obtaining stable estimates of both steep and gradual changes in velocity. We also demonstrate that our proposed method is robust to variations in the amplitude of the velocity jump, the initial velocity model, and the number of observed arrival times, compared with conventional approaches, and verify the adaptability of the proposed method to dipping discontinuities. Furthermore, we apply our proposed method to real seismic data in central Japan and present the potential of our method for detecting velocity discontinuities using the observed arrival times from a small number of local earthquakes. Graphical Abstract

Abstract Background Enteric duplication is a congenital disease that occurs throughout the entire gastrointestinal tract. Although it may sometimes cause intestinal volvulus, a few reports have described cases of enteric duplication twisted on itself. We experienced a rare pediatric case of long-segment tubular ileal duplication showing torsion. Torsion of enteric duplication is extremely rare. We herein report a pediatric case showing unusual torsion of ileal duplication requiring emergency surgery. Case presentation A 3-year-old boy presented with abdominal pain and vomiting. Contrast-enhanced computed tomography (CT) revealed a cystic luminal structure with a blind end and fluid collection in the pelvic cavity. CT also showed no findings of ileus or intestinal dilatation except for a cystic luminal structure. The preoperative diagnosis was torsion of Meckel’s diverticulum. The patient underwent emergent explorative diagnostic laparoscopy. As a result, a necrotic luminal structure and bloody ascites were recognized, and small-scale laparotomy was performed. Long-segment ileal duplication was recognized. The long-segment tubular ileal duplication shared the anti-mesenteric side of the intestinal wall along one-third of its length. The residual two-thirds of its length was free from the ileum and its blind end was twisted in a manner that looked similar to Meckel’s diverticulum. Normal ileum and the duplication, including the twisted necrotic portion, were resected, and ileal anastomosis was performed. The postoperative course was uneventful. A pathological examination confirmed the definitive diagnosis of enteric duplication. Conclusions We reported the unusual presentation of intestinal duplication mimicking torsion of Meckel’s diverticulum. Enteric duplication shows various clinical symptoms and presentations. We must understand that the classification of digestive enteric duplication is diverse with a variety of associated clinical symptoms.

Abstract Low-frequency tremors have been widely detected in many tectonic zones, and are often located adjacent to megathrust zones, indicating that their spatiotemporal evolution provides important insights into megathrust events. The envelope correlation method (ECM) is commonly used to detect tremors. However, the ECM also detects regular earthquakes, which requires the separation of these two signals after the initial detection. In addition, signals of tremors are weak, so classifying tremors from noises is also an essential problem. We develop a convolutional neural network (CNN)-based method using a single S-net station located off Sanriku region, Northeast Japan, to classify local earthquakes, tremors, and noise. Along the Japan Trench, especially in a region focused in this study, local earthquakes and tremors occurred in coexistence within a small region, so detection, location, and discrimination of these events are the key to understand the relationship between slow and regular earthquakes. The spectrograms of the three-component velocity waveforms that were recorded during 16 August 2016 to 14 August 2018 are used as the training and test datasets for the CNN. The CNN successfully classified 100%, 96%, and 98% of the earthquakes, tremors, and noise, respectively. We also showed a successful application of our method to continuous waveform data including a tremor to explore the feasibility of the proposed method in classifying tremors and noise in continuous streaming data. The output probabilities for the true classifications decrease with increasing epicentral distance and/or decreasing event magnitude. This highlights the need to train the CNN using tremors proximal to the seismic stations for detecting tremors using multiple stations.

Abstract Background Accessory liver lobe (ALL) is a rare liver malformation. An ALL develops due to malformation of the endodermal caudal foregut and segmentation of the hepatic bud in the third week of gestation. Most ALLs are asymptomatic and are detected incidentally during abdominal surgery. The incidence of ALL is

Laparoscopic surgery has been applied for Hirschsprung's disease (HD). We herein report our approach to mesenteric processing for laparoscopic-assisted transanal endorectal pull-through (L-TERPT). Following mucosectomy and entering the abdominal cavity, a vessel sealing system is transanally inserted into the abdominal cavity for mesenteric processing based on concept of Natural Orifice Translumenal Endoscopic Surgery. Since the transanal axis is parallel to the dissected mesentery, it makes easier to operate in comparison to when the procedure is performed through the abdominal working port and can reduce the additional abdominal trocar wound. We also use indocyanine green (ICG) fluorescence navigation. Fluorescing the vessels with ICG allows intraoperative visualization of the blood flow in the retrieved intestine. With these innovative combined techniques, L-TERPT for HD can be safely performed, even in infants with small intraabdominal cavities.

We investigate the asymptotic construction of constant-risk Bayesian predictive densities under the Kullback–Leibler risk when the distributions of data and target variables are different and have a common unknown parameter. It is known that the Kullback–Leibler risk is asymptotically equal to a trace of the product of two matrices: the inverse of the Fisher information matrix for the data and the Fisher information matrix for the target variables. We assume that the trace has a unique maximum point with respect to the parameter. We construct asymptotically constant-risk Bayesian predictive densities using a prior depending on the sample size. Further, we apply the theory to the subminimax estimator problem and the prediction based on the binary regression model.