Laparoscopic sigmoid colectomy for transverse colonic varices due to an inferior mesenteric arteriovenous fistula

BACKGROUND

Colonic varices are a rare gastrointestinal anomaly often associated with portal hypertension. Arteriovenous fistula (AVF) in the inferior mesenteric artery (IMA) region is even rarer. Diagnosis and treatment of these entities present unique challenges, especially when the IMA is involved.

CASE PRESENTATION

A 48-year-old man with a history of cholecystectomy presented with after a positive fecal occult blood test. Investigations revealed varices from the splenic flexure to the transverse colon and suspected AVF in the IMA region. Given the high risk and low efficacy of endoscopic and radiological interventions, laparoscopic sigmoidectomy was performed. This surgical approach successfully addressed both the AVF and the associated varices.

CONCLUSION

This case underscores the importance of surgical intervention for AVF and colonic varices in the IMA region, particularly when other treatment options pose high risks and have limited efficacy. The favorable postoperative outcome in this case highlights the effectiveness of carefully chosen surgical methods when managing such complex and rare conditions.

A case of endoscopic full-thickness resection for gastric gastrointestinal stromal tumor in the submucosal tunnel

The patient was a 49-year-old female with a submucosal tumor (12×12 mm) located in the lesser curvature side of the stomach. The diagnosis by endoscopic ultrasound fine-needle aspiration was of a gastrointestinal stromal tumor. Computed tomography and endoscopic ultrasound showed gastrointestinal stromal tumor with an intra-luminal growth type. Endoscopic full-thickness resection was then performed. To achieve good counter traction, enough safety margin, and minimal defect of muscle, full-thickness resection via creating a submucosal tunnel was performed as a new technique. The final histological diagnosis was gastrointestinal stromal tumor with R0 resection.

Endoscopic ligation technique for refractory gastrotracheal fistula

Endoscopic therapy has recently undergone remarkable progress, including the use of suturing procedures within the gastrointestinal tract using flexible endoscopes. However, existing suturing techniques primarily involve closure using instruments or continuous sutures using an endoscopic needle holder, leaving a gap in nodal suturing methods with extracorporeal ligation. This paper introduces a novel approach, the endoscopic ligation technique, wherein a flexible endoscope is utilized for nodal suturing through extracorporeal ligation.

A pilot study on the safety and efficacy of neoadjuvant chemo‑adoptive immunotherapy for locally advanced rectal cancer

The safety and efficacy of combination therapy of immune cell therapy and chemotherapy [chemo-adoptive immunotherapy (CAIT)] for patients with stage IV or recurrent colorectal cancer have been reported. In the present study, the safety and efficacy of neoadjuvant CAIT were investigated for preoperative therapy of locally advanced rectal cancer. The study included patients with cT3/T4 or cN (+) rectal adenocarcinoma scheduled for curative surgery. Six patients who consented to participate in the current study were selected as subjects. Neoadjuvant CAIT involves administration of activated autologous lymphocytes, αβ T cells, and mFOLFOX6 every 2 weeks for six courses, followed by surgery 4-6 weeks thereafter. Common Terminology Criteria for Adverse Events grade 3 neutropenia was observed in one patient. Neoadjuvant CAIT and curative surgery were performed on all the patients. The confirmed response rate was 67%. Downstaging was confirmed in five patients (83%). Regarding histological effects, two patients were grade 1a and four were grade 2. Regarding immunological reactions, both CD4+ and CD8+ T cell infiltration rates increased after treatment in three patients on tumor-infiltrating lymphocyte (TIL) analysis. In peripheral blood analysis, the total lymphocyte count was maintained in all patients, and the CD8+ T cell count increased by ≥3 times on the pretreatment count in two patients but may not be associated with changes in TILs. During the median postoperative follow-up duration of 24 months, liver and lung metastases occurred in one patient, but all patients survived. In conclusion, neoadjuvant CAIT (αβ T cells + mFOLFOX6) can be safely administered for the treatment of advanced rectal cancer. Verification of the efficacy of comprehensive immune cell therapy, especially the induction of antitumor immunity for the prevention of recurrence, will be maintained. The current study is registered with the Japan Registry of Clinical Trials (jRCT; ID, jRCTc030190248; January 21, 2019).

Enzymatic Fat Dissolution Improves Detection of Small Lymph Nodes in Colon Cancer Surgery

Background Accurate lymph node evaluation is essential for staging colon cancer and guiding postoperative treatment decisions. In this study, we compared the efficacy of a simple enzymatic fat dissolution method with the conventional method for lymph node sampling from specimens after colon cancer surgery. Methods We enrolled 58 patients who underwent elective laparoscopic surgery for colon adenocarcinoma between May 2018 and May 2021 at Fukuoka University Hospital in Fukuoka, Japan. The specimens from these patients were treated using fat dissolution and were compared with specimens from 58 patients for which conventional manual palpation was used. Results A significantly greater number of lymph nodes were detected by the fat dissolution method compared with the conventional method (average per patient, 27.5 vs. 22.6, P = 0.02). In particular, the between-group difference was significant for lymph nodes measuring <5 mm (average per patient, 26.1 vs. 20.9; P = 0.01). Multivariate analysis showed that, compared with the conventional method, the fat dissolution method was significantly associated with the identification of lymph node metastasis. The positive rate of lymph nodes ≥10 mm in diameter was markedly higher along the inferior mesenteric artery than the ileocolic artery (100% vs. 52.6%). Conclusions The use of the fat dissolution method led to an increase in the number of small lymph nodes detected. Rates of metastasis according to lymph node size may depend on the lymph node station.

Effect of heating insufflation tube of AirSeal system on laparoscopic surgery

The AirSeal system (CONMED, NY, USA) can outstandingly keep pneumoperitoneum stable. However, water droplets form on the access port, impairing the performance of comfortable surgical procedures because of the resultant wet surgical field. This study was performed to clarify the mechanism of water droplet formation and to prevent it. Condensation was observed on the AirSeal system. A heater was wrapped around the tri-lumen tube, and the heating effect was assessed. The simulator experiments revealed that condensation formed in the tri-lumen tube and on the wall of the access port. The accumulated weight of the condensation on the wall of the access port was 41.6 g in the Heated group, 138.2 g in the Control group, and 479.4 g in the Cooled group. In the clinical assessment, the accumulated volume of the condensation attached to the inside wall was significantly smaller in the Heated group than in the Unheated group (111.7 g vs. 332.9 g, respectively). We clarified that the volume of condensation attached to the wall of the access port depended on the temperature of the tri-lumen tube. The clinical study revealed that the condensation on the access port was reduced by heating the tri-lumen tube. The development of a novel heating device for the insufflation tube would be effective and useful.

Impact of the lateral skeletal stability following bilateral sagittal split ramus osteotomy for mandibular asymmetry

This study evaluated the stability of bilateral sagittal split ramus osteotomy (BSSRO) associated with positional plagiocephaly and temporal and masseter muscles using posteroanterior cephalogram analysis and three-dimensional computed tomography (3D-CT). This retrospective cohort study included 31 patients who underwent BSSRO for mandibular asymmetry. The cranial vault asymmetry index (CVAI) and the cephalic index were used as indicators of positional plagiocephaly. The distance from the vertical reference line to the menton (Me) was measured on posteroanterior cephalograms immediately and 1 year after surgery, and postoperative stability was assessed. Temporal and masseter muscles were constructed from 3D-CT data and their volumes were measured. Simple regression analysis showed a significant correlation between postoperative changes in the vertical reference line to the Me and the CVAI (R = 0.56, p = 0.001), the amount of surgical movement in the vertical reference line to the Me (R = 0.41, p = 0.023), and the variable temporal muscle volume (R = 0.27, p = 0.028). There was no significant correlation between postoperative changes in the vertical reference line to the Me and the cephalic index (R = 0.093, p = 0.62) and variable masseter muscle volume (R = 0.16, p = 0.38). According to multivariate analysis, CVAI (p = 0.003) and amount of surgical movement in the vertical reference line to the Me (p = 0.014) were significant predictors of postoperative change in the vertical reference line to the Me. Positional plagiocephaly and amount of surgical movement influence lateral skeletal stability following BSSRO for mandibular asymmetry.

Safety and Feasibility of Gastrectomy in Super Elderly Patients (Aged ≥ 80): A Propensity Score-Matched Analysis

INTRODUCTION

The benefits of gastrectomy in elderly patients with gastric cancer (GC) remain unknown. This study was conducted to evaluate the short- and long-term outcomes of elderly patients with GC (≥ 80 years) who underwent gastrectomy.

METHODS

We enrolled 479 patients (Stages I-IV) who underwent gastrectomy with R0-1 resection. The patients were divided into an elderly group (E group; age ≥ 80 years) (n = 115) and a non-elderly group (NE group; age < 80 years) (n = 364). After propensity score matching (PSM) was performed, the short- and long-term outcomes were compared between the groups.

RESULTS

The rate of postoperative complications (Clavien-Dindo classification ≥ IIIa) in the two groups did not differ significantly (p = 0.657). Before PSM, the five-year overall survival (OS, 35.3% vs. 71.7%, p < 0.001) and disease-specific survival (DSS, 56.8% vs. 81.8%, p < 0.001) in the E group were significantly shorter than that in the NE group, respectively. On the other hand, significant differences between the E and NE groups were not shown in either the five-year OS (35.5% vs. 50.8%, p = 0.0985) or the five-year DSS (56.5% vs. 66.9%, p = 0.274) after PSM.

CONCLUSION

Gastrectomy for elderly patients with GC can be considered safe based on short-term outcomes. In terms of long-term results, elderly patients are not inferior to non-elderly patients if the patients' backgrounds are the same. On the other hand, the long-term outcomes of elderly GC patients who have various comorbidities are not satisfactory, so we should carefully consider the indications for gastrectomy.

Management of Patients Receiving Antiplatelet Therapy During Gastroenterological Surgery: A Multicenter Prospective Cohort Study (GSATT)

OBJECTIVE

This study aimed to evaluate the effect of continuing preoperative aspirin monotherapy on surgical outcomes in patients receiving antiplatelet therapy (APT).

SUMMARY BACKGROUND DATA

The effectiveness of continuing preoperative aspirin monotherapy in patients undergoing APT in preventing thromboembolic consequences is mostly unknown.

METHODS

This prospective multicenter cohort study on the Safety and Feasibility of Gastroenterological Surgery in Patients Undergoing Antithrombotic Therapy (GSATT study) conducted at 14 clinical centers enrolled and screened patients between October 2019 and December 2021. The participants (n=1,170) were assigned to the continued APT group, discontinued APT group, or non-APT group, and the surgical outcomes of each group were compared. Propensity score matching was performed between the continued and discontinued APT groups to investigate the effect of continuing preoperative aspirin therapy on thromboembolic complications.

RESULTS

The rate of thromboembolic complications in the continued APT group was substantially lower than that in the non-APT or discontinued APT groups (0.5% vs. 2.6% vs. 2.9%; P=0.027). Multivariate investigation of the entire cohort revealed that discontinuation of APT (P<0.001) and chronic anticoagulant use (P<0.001) were independent risk factors for postoperative thromboembolism. The post-matching evaluation demonstrated that the rates of thromboembolic complications were significantly different between the continued and discontinued APT groups (0.6% vs. 3.3%; P=0.012).

CONCLUSIONS

APT discontinuation following elective gastroenterological surgery increases the risk of thromboembolic consequences, whereas continuing preoperative aspirin greatly reduces this risk. The continuation of preoperative aspirin therapy in APT-received patients is considered one of the best alternatives for preventing thromboembolism during elective gastroenterological surgery.

Preoperatively diagnosed intraductal oncocytic papillary neoplasm of the pancreas with prominent invasion: a case report

Previously considered as one of the less-invasive subtypes of intraductal papillary mucinous neoplasm, intraductal oncocytic papillary neoplasm (IOPN) has recently been acknowledged as a new entity of pancreatic tumor. We herein present a case of preoperatively diagnosable IOPN invasion in the stomach and colon. A 78-year-old woman was referred to our hospital for evaluation of anorexia and gastroesophageal reflux. Upper gastrointestinal endoscopy revealed a gastric subepithelial lesion with ulcerated mucosa that required hemostasis. Computed tomography revealed a 96-mm-diameter solid tumor with a well-defined border and centrally positioned necrotic area, extending from the stomach to the transverse colon and pancreatic tail. Because it was suspected to be a pancreatic solid tumor with direct stomach invasion, endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) was performed, which led to a preoperative diagnosis of IOPN. Moreover, laparoscopic pancreatosplenectomy, proximal gastrectomy, and transverse colectomy were performed. Analysis of the surgical specimen revealed that the tumor was IOPN and had invaded the stomach and transverse colon. Lymph node metastasis was also confirmed. These findings indicate that IOPN can manifest as an invasive tumor, and EUS-FNB may be equally helpful for assessing the invaded area of a cystic lesion as it is for a solid lesion.

Conversion to Curative Resection and Pathological Complete Response Following Targeted Therapies With Atezolizumab and Bevacizumab for Initially Unresectable Hepatocellular Carcinoma: A Case Report

Hepatocellular carcinoma is a malignancy with an increasing incidence worldwide and is one of the most serious cancers in adults. We encountered a case of initially unresectable massive hepatocellular carcinoma in which conversion to curative resection and pathological complete response were achieved after atezolizumab plus bevacizumab therapy. Atezolizumab plus bevacizumab combination chemotherapy may be one of the most promising options for unresectable hepatocellular carcinoma.

Trans-anal Minimally Invasive Surgery Combined With a Robotic Anterior Approach for Sleeve Resection of a Huge Rectal Gastrointestinal Stromal Tumor

Due to anatomical complexity, large rectal gastrointestinal stromal tumors (GISTs) in the pelvis at the anterior aspect often require extended abdominal surgery to obtain clear surgical margins. Here, we show our trans-anal minimally invasive surgery combined with a robotic anterior approach for a huge low rectal GIST that was widely in contact with the prostate and urethra. By performing lateral dissection first, we can identify the orientation of critical organs such as the prostate, urethra, and neurovascular bundles, facilitating anterior anorectal dissection without urethral injury. Although the combination with a transabdominal robotic approach was required because of firm inflammatory adhesion between the tumor and prostate, the preceding trans-anal dissection plane facilitated the robotic anterior dissection and contributed to achieving complete dissection with negative resection margins.

Application of Extended Reality (Virtual Reality and Mixed Reality) Technology in Laparoscopic Liver Resections

Background and purpose Laparoscopic liver resection (LLR) has recently gained popularity owing to advances in surgical techniques. Difficulties in LLR may be influenced by anatomical factors. This study presents a comprehensive overview of LLR performed using extended reality (XR) technology. Methods Six patients underwent LLR performed wearing HoloLens2® XR (Microsoft Corporation, Redmond, Washington, United States) technology. We performed dynamic contrast-enhanced CT scans before surgery and used the data to construct three-dimensional images. Results Of the six patients, two were diagnosed with colorectal liver metastases, two with hepatocellular carcinoma, and one with intrahepatic cholangiocarcinoma. The median maximum tumor diameter was 31 mm (range, 23-80 mm). One patient had liver cirrhosis, with Child-Pugh classification grade B. Anatomical resection was performed in three patients (60%), with a median difficulty score of 7 (intermediate). No conversions to open surgery were necessary. The median operative time and estimated blood loss were 444 minutes (range, 337-597 minutes) and 200 mL (range, 100-1000 mL), respectively. Postoperative complications (Clavien-Dindo classification grade II) were observed in one patient. All six cases achieved negative surgical margins. Conclusions LLR using XR technology enhances surgical visualization and anatomical recognition. The incorporation of XR technology into LLR offers advantages over traditional two-dimensional imaging.

Azimuthal Correlations within Exclusive Dijets with Large Momentum Transfer in Photon-Lead Collisions

The structure of nucleons is multidimensional and depends on the transverse momenta, spatial geometry, and polarization of the constituent partons. Such a structure can be studied using high-energy photons produced in ultraperipheral heavy-ion collisions. The first measurement of the azimuthal angular correlations of exclusively produced events with two jets in photon-lead interactions at large momentum transfer is presented, a process that is considered to be sensitive to the underlying nuclear gluon polarization. This study uses a data sample of ultraperipheral lead-lead collisions at sqrt[s_{NN}]=5.02  TeV, corresponding to an integrated luminosity of 0.38  nb^{-1}, collected with the CMS experiment at the LHC. The measured second harmonic of the correlation between the sum and difference of the two jet transverse momentum vectors is found to be positive, and rising, as the dijet transverse momentum increases. A well-tuned model that has been successful at describing a wide range of proton scattering data from the HERA experiments fails to describe the observed correlations, suggesting the presence of gluon polarization effects.

The Safety of Laparoscopic Cholecystectomy in Super-elderly Patients: A Propensity Score Matching Analysis

BACKGROUND

Although reports on the safety of laparoscopic cholecystectomy (LC) exist, few have included patients aged ≥ 85 years. Hence, our study aimed to evaluate surgical outcomes of LC in patients aged ≥ 85 years.

METHODS

After excluding patients who underwent other types of surgeries, 583 patients who underwent LC between 2015 and 2022 were included. Patients were classified into two groups based on age: < 85 years (control group, n = 551) and ≥ 85 years (super-elderly group, n = 32). Propensity score matching (PSM) was performed based on preoperative clinical parameters, and intraoperative and postoperative outcomes were compared.

RESULTS

After PSM, 28 patients were included in each group. Intraoperative blood loss (1 vs. 5 mL, respectively; P = .052) and frequency of serious postoperative complications (Clavien-Dindo class ≥ 2, 2/28 (7.1%) vs. 6/28 (21.4%), P = .252) were similar between the control and elderly groups. There was no significant difference in the length of postoperative stay (control group: 5 (4-24) days vs. super-elderly group: 7 (3-64) days, P = .236). Unfortunately, one case of pneumonia of unknown cause occurred postoperatively, resulting in the death of one patient in the super-elderly group.

CONCLUSIONS

There were no clinically significant differences in the short-term outcomes of LC between super-elderly patients aged ≥ 85 years and patients aged < 85 years. Hence, LC may be relatively safe even in patients aged ≥ 85 years. However, owing to many pre-existing diseases and deterioration of physiological function, careful management during the perioperative period is desirable.

Measurement of Direct-Photon Cross Section and Double-Helicity Asymmetry at sqrt[s]=510 GeV in p[over →]+p[over →] Collisions

We present measurements of the cross section and double-helicity asymmetry A_{LL} of direct-photon production in p[over →]+p[over →] collisions at sqrt[s]=510  GeV. The measurements have been performed at midrapidity (|η|<0.25) with the PHENIX detector at the Relativistic Heavy Ion Collider. At relativistic energies, direct photons are dominantly produced from the initial quark-gluon hard scattering and do not interact via the strong force at leading order. Therefore, at sqrt[s]=510  GeV, where leading-order-effects dominate, these measurements provide clean and direct access to the gluon helicity in the polarized proton in the gluon-momentum-fraction range 0.02<x<0.08, with direct sensitivity to the sign of the gluon contribution.

Comparison of changes in health-related quality of life between elderly and non-elderly patients undergoing elective surgery for colorectal cancer

PURPOSE

Elderly people are thought to be more likely than their non-elderly counterparts to experience a decline in activities of daily living (ADL) and quality of life (QOL) due to the onset and treatment of disease. In this study, we investigated whether there was an age-related difference in changes in health-related QOL indices after surgical resection of colorectal cancer (CRC).

METHODS

Patients who underwent elective surgery for primary CRC at our hospital between September 2017 and November 2021 were enrolled. Changes in QOL after surgery were evaluated after dividing the study population into a non-elderly (NE) group (younger than 75 years) and an elderly (E) group. A Short-Form 36-Item Health Survey was used as an index of QOL. The subscale and component summary scores before and 6 months after surgery were compared.

RESULTS

Forty-seven patients were included in the E group and 166 patients were the NE group. The E group had significantly worse preoperative performance and physical status than the NE group. However, indices of physical function were not worsened after surgery in either group. In the NE group, there were significant decreases in role physical and role component summary scores and significant increases in general health, mental health, and mental component summary scores. In the E group, there were no significant changes in the subscale or component summary scores after surgery.

CONCLUSION

Our study demonstrated elderly patient did not necessarily show a decline in QOL more than non-elderly patients after CRC surgery. Surgical resection for CRC should be considered even for elderly patients, while considering possible risk factors for worsening ADL and QOL.

Current approach for Boerhaaves syndrome: A systematic review of case reports

BACKGROUND

There is no consensus on the appropriate therapeutic strategy for Boerhaave syndrome due to its rarity and changing therapeutic approaches. We conducted a systematic review of case reports documenting Boerhaave syndrome.

AIM

To assess the therapeutic methods and clinical outcomes and discuss the current trends in the management of Boerhaave syndrome.

METHODS

We searched PubMed, Google scholar, MEDLINE, and The Cochrane Library for studies concerning Boerhaave syndrome published between 2017 and 2022.

RESULTS

Of the included studies, 49 were case reports, including a total of 56 cases. The mean age was 55.8 ± 16 years old. Initial conservative treatment was performed in 25 cases, while operation was performed in 31 cases. The rate of conservative treatment was significantly higher than that of operation in cases of shock vital on admission (9.7% vs 44.0%; P = 0.005). Seventeen out of 25 conservative cases (68.0%) were initially treated endoscopic esophageal stenting; 2 of those 17 cases subsequently underwent operation due to poor infection control. Twelve cases developed postoperative leakage (38.7%), and 4 of those 12 cases underwent endoscopic esophageal stenting to stop the leakage. The length of the hospital stay was not significantly different between the conservative treatment and operation cases (operation vs conservation: 33.52 ± 22.69 vs 38.81 ± 35.28 days; P = 0.553).

CONCLUSION

In the treatment of Boerhaave syndrome, it is most important to diagnose the issue immediately. Primary repair with reinforcement is the gold-standard procedure. The indication of endoscopic esophageal stenting or endoluminal vacuum-assisted therapy should always be considered for patients in a poor general condition and who continue to have leakage after repair.

Middle Hepatic Vein-Guided Cranial and Hilar Approach Using a Modified Two-Surgeon Technique in Laparoscopic Extended Left Medial Sectionectomy: A Technical Case Report With Videos

Anatomical liver resection and liver resection close to major blood vessels are quite challenging and require a high level of expertise. In addition, anatomical hepatectomy requires extensive knowledge of the positions of blood vessels and techniques for hemostasis because the resection surface is extensive and operations around blood vessels are required. A hepatic vein-guided cranial and hilar approach using a modified "two-surgeon technique" is effective in resolving these problems. Herein, we present a middle hepatic vein (MHV)-guided cranial and hilar approach using a modified two-surgeon technique in laparoscopic extended left medial sectionectomy to resolve these problems. This procedure is feasible and effective.

Quick and Easy Application Method of TachoSil®️ During Laparoscopic and Robotic Liver Resections

TachoSil®️, a fibrin sealant patch, is a sheet-type hemostatic agent. Therefore, it is technically demanding to put it on the target place especially in laparoscopic surgeries due to the motion restriction of straight-fixed instruments. This article describes a quick and easy technique of TachoSil application during laparoscopic liver surgeries, by sewing it to the laparoscopic gauze in advance. This method allows for one-handed operation and stress-free application even in the situation of active bleeding.

A Case of Posterior Interosseous Nerve Palsy Associated With Robotic Low Anterior Resection

A peripheral nerve compression injury associated with surgical positioning is an important complication that might compromise quality of life. We report a rare case of posterior interosseous nerve (PIN) palsy after robotic rectal cancer surgery. A 79-year-old male with rectal cancer underwent robotic low anterior resection in a modified lithotomy position with both arms tucked at his sides with bed sheets. Following surgery, he felt difficulty moving his right wrist and fingers. A neurological examination revealed muscle weakness in the area innervated by the PIN alone without sensory disturbance, and he was diagnosed with PIN palsy. The symptoms improved with conservative treatment in about a month. The PIN is a branch of the radial nerve and controls dorsiflexion of the fingers, and intraoperative continuous pressure on the upper arm by right lateral rotation position or by the robot arm was considered to be the cause.

Non-Stick Liver Parenchymal Transection With Saline-Linked Bipolar Clamp-Crush Technique in Robotic Liver Resection

Background Without satisfactory instruments, liver parenchymal transection during robotic liver resection (RLR) remains challenging. We combined the commonly used bipolar clamp-crush technique with the saline drip, achieving a comfortable liver resection without coagulated liver tissues sticking to the bipolar forceps. Methods Between December 2022 and March 2023, six RLRs were performed using the saline-linked bipolar clamp-crush method for both anatomical and non-anatomical liver resections. We assessed the safety and feasibility of our robotic liver parenchymal transection technique. Results Three of six patients were diagnosed with colorectal liver metastasis, two with hepatocellular carcinoma (HCC), and the other with intrahepatic bile duct stricture. Three of the six patients received anatomical liver resection, and the other three underwent non-anatomical liver resection. There were no conversions to open surgery. The median operative time and estimated blood loss were 406.5 minutes (196-670 minutes) and 5 ml (5-465 ml), respectively. The median length of the postoperative hospital stay was nine days (7-10 days). Postoperative complications (Clavien-Dindo classification grade II or more) or mortality were not encountered in this cohort. Conclusion We presented here our saline-linked bipolar clamp-crush method for liver parenchymal transection in RLR. By simply adding the saline drip to the commonly used bipolar clamp-crush technique, non-stick and comfortable liver parenchymal transection is now possible. This technique may help overcome the limitations of currently available robotic instruments for liver parenchymal resection.

Long-term results of a phase 2 study of neoadjuvant chemotherapy with molecularly targeted agents for locally advanced rectal cancer

BACKGROUND

We previously reported the feasibility and efficacy of neoadjuvant chemotherapy without radiotherapy for locally advanced rectal cancer. Here, we report the results of a long-term follow-up study.

METHODS

This was a multi-institutional, prospective phase 2 study of patients with locally advanced rectal cancer. Patients received neoadjuvant chemotherapy with molecularly targeted agents before undergoing total mesorectal excision. Six cycles of modified FOLFOX (mFOLFOX6) with bevacizumab were administered to KRAS-mutant patients, and mFOLFOX6 with cetuximab was administered to KRAS-wild-type patients. Here, we report the secondary end points of overall survival, relapse-free survival, and local recurrence rate.

RESULTS

Sixty patients were enrolled in this study. R0 resection was achieved in 98.3% (59/60) patients, and pathological complete response was achieved in 16.7% (10/60) patients. After a median follow-up of 5.4 years, the 5 year overall survival was 81.6%, the 5 year relapse-free survival was 71.7%, and the 5 year local recurrence rate was 12.6%. None of the patients who achieved pathological complete response developed recurrence within 5 years.

CONCLUSIONS

The use of molecularly targeted agents in the neoadjuvant setting for locally advanced rectal cancer has an acceptable prognosis.

Measurements of the associated production of a W boson and a charm quark in proton-proton collisions at s = 8 TeV

Measurements of the associated production of a W boson and a charm ( c ) quark in proton-proton collisions at a centre-of-mass energy of 8 TeV are reported. The analysis uses a data sample corresponding to a total integrated luminosity of 19.7 fb - 1 collected by the CMS detector at the LHC. The W bosons are identified through their leptonic decays to an electron or a muon, and a neutrino. Charm quark jets are selected using distinctive signatures of charm hadron decays. The product of the cross section and branching fraction σ ( pp → W + c + X ) B ( W → ℓ ν ) , where ℓ = e or μ , and the cross section ratio σ ( pp → W + + c ¯ + X ) / σ ( pp → W - + c + X ) are measured in a fiducial volume and differentially as functions of the pseudorapidity and of the transverse momentum of the lepton from the W boson decay. The results are compared with theoretical predictions. The impact of these measurements on the determination of the strange quark distribution is assessed.

Reconstruction with omental flap and negative pressure wound therapy after total pelvic exenteration of anal fistula cancer: a case report

Introduction

Surgery for anal fistula cancer (AFC) associated with Crohn’s disease usually entails extensive perineal wounds and dead space in the pelvis, which is often filled with a myocutaneous flap. However, use of a myocutaneous flap is invasive. We report a case of total pelvic exenteration (TPE) for AFC in which a myocutaneous flap was avoided by using an omental flap and negative pressure wound therapy (NPWT).

Case presentation

The patient was a 47-year-old woman who had been treated for Crohn’s disease involving the small and large intestine for 30 years and had repeatedly developed anal fistulas. She was referred with a diagnosis of AFC that had spread extensively in the pelvis. We performed laparoscopic TPE via a transperineal endoscopic approach. To prevent infection in the large skin defect and extensive pelvic dead space postoperatively, the perineal wound was reconstructed using an omental flap and NPWT. During 20 days of NPWT, the wound steadily decreased in size and closed on postoperative day (POD) 20. She was discharged without complications on POD 30.

Discussion

NPWT is useful for preventing perineal wound infection and promoting granulation tissue formation. However, direct contact with the intestine may lead to intestinal perforation. In this case, the combination of an omental flap with NPWT effectively prevented surgical site infection. The flap filled the large pelvic dead space and physically separated the intestine from the polyurethane foam used for NPWT.

Conclusion

NPWT and an omental flap may become an option when performing TPE.

Comparison of oncological outcomes between low anterior resection and abdominoperineal resection for rectal cancer: A retrospective cohort study using a multicenter database in Japan

BACKGROUND

It remains controversial whether the abdominoperineal resection (APR) procedure itself has a negative impact on prognosis compared with sphincter-saving surgery (SSS). The purpose of this study was to investigate whether the operation type affects the prognostic outcome in rectal cancer using a multicenter database in Japan.

METHODS

The study involved 2533 patients who underwent APR or SSS and were registered in the Japanese Society for Cancer of the Colon and Rectum database, which includes data from 74 centers, between 2003 and 2007. The primary endpoints were overall survival (OS) and relapse-free survival (RFS). The secondary endpoints were local recurrence rate (LRR) and pathological radial margin (pRM) status.

RESULTS

Multivariate analysis identified pathological tumor depth, lymph node status, and pRM status to be associated with oncological outcomes (OS, RFS, LRR). Although the oncological outcomes were worse after APR than after SSS in univariate analysis, there was no significant difference in OS (hazard ratio 1.08; 95% confidence interval [CI] 0.85-1.37) or RFS (hazard ratio 1.06; 95% CI 0.87-1.30) between APR and SSS. There was also no significant difference in LRR (odds ratio 1.11, 95% CI 0.70-1.77). Multivariate analysis showed that operation type was associated with positive pRM (odds ratio 3.13, 95% CI 0.18-0.56).

CONCLUSIONS

There was no significant difference in oncological outcomes between APR and SSS for rectal cancer. The risk of positive pRM was higher for APR and performing radial margin-negative surgery is an important factor in improving the oncological outcomes of APR.

Biweekly TAS-102 and bevacizumab as third-line chemotherapy for advanced or recurrent colorectal cancer: a phase II, multicenter, clinical trial (TAS-CC4 study)

BACKGROUND

TAS-102 improves overall survival (OS) of patients with refractory colorectal cancer (CRC), resulting in median progression-free survival (PFS) of 2.0 months (RECOURSE trial). Subsequently, a combination of TAS-102 and bevacizumab was shown to extend median PFS by 3.7 months. However, approximately half of these patients experience grade 3/4 neutropenia. In this study, we evaluated whether biweekly TAS-102 and bevacizumab therapy has efficacy equal to that of conventional TAS-102 and bevacizumab therapy and whether it reduces adverse hematological effects.

METHODS

This phase II, investigator-initiated, open-label, single-arm, multicenter study was conducted in Japan. Eligible patients had previously received first- and second-line chemotherapy for metastatic CRC. TAS-102 (35 mg/m²) was given twice daily on days 1-5 and days 15-19 in a 4-week cycle, and bevacizumab (5 mg/kg) was administered by intravenous infusion for 30 min every 2 weeks. The primary end point was progression-free survival (PFS), and secondary end points were time-to-treatment failure (TTF), response rate (RR), OS, and safety.

RESULTS

44 patients with metastatic colorectal cancer were enrolled in this study. Median PFS was 4.6 months (95% confidence interval [95% CI] 3.6-5.3) and median OS was 10.5 months (95% CI 9.6-11.4). A partial response was observed in 2 patients (4.5%, 95% CI 0.4-16.0%). The most common adverse event above grade 3 was neutropenia (7 patients, 15.9%, 95% CI 7.6-29.7%).

CONCLUSIONS

Biweekly TAS-102 and bevacizumab therapy as third-line chemotherapy appears as effective as conventional TAS-102 and bevacizumab therapy, and this approach reduces adverse hematological effects.

Impact of AirSeal® insufflation system on respiratory and circulatory dynamics during laparoscopic abdominal surgery

The effect of the AirSeal^® insufflation system on hemodynamic parameters, especially end-tidal carbon dioxide (EtCO₂), during laparoscopic abdominal surgery remains unclear. This retrospective single-center study included 333 consecutive patients who underwent laparoscopic hepatectomy (n = 43), gastrectomy (n = 69), colectomy (n = 137), or proctectomy (n = 84) using the AirSeal^®. Patient demographics and intraoperative hemodynamic parameters, such as EtCO₂, peripheral capillary oxygen saturation (SpO₂), and arterial systolic blood pressure (ABP), were collected and analyzed. EtCO₂ was evaluated during the entire operative period (whole period) as well as the pneumoperitoneum period until specimen removal (pneumoperitoneum period). We defined “positive respiratory and circulatory responses” (positive responses) as a decrease in EtCO₂ ≥ 3 mmHg in addition to decreases in SpO₂ ≥ 3% and ABP ≥ 10 mmHg simultaneously, which suggest possible carbon dioxide (CO₂) embolism. The median EtCO₂ values of hepatectomy, gastrectomy, colectomy, and proctectomy in the whole period/pneumoperitoneum period were 37.3/37.4, 37.1/37.3, 37.4/37.9, and 38.2/38.4 mmHg, respectively. The EtCO₂ of proctectomy was significantly higher than that of gastrectomy during the whole and pneumoperitoneum periods (P < 0.05). In contrast, the EtCO₂ of hepatectomy was comparable to that of the other three surgeries in the whole and pneumoperitoneum periods. Meanwhile, nine (2.7%; eight hepatectomies and one proctectomy) patients showed positive responses, and one who underwent a partial hepatectomy developed a clinically manifested CO₂ embolism. Positive responses occurred during venous exposure or bleeding in all nine cases. Although the EtCO₂ of hepatectomy was comparable to that of the other surgeries using the AirSeal^®, laparoscopic hepatectomy showed a tendency of CO₂ embolism. Thus, a secure and careful surgical approach is mandatory for laparoscopic hepatectomy using the AirSeal^® insufflation system.

Risk factors and long-term course of gastroesophageal reflux disease after peroral endoscopic myotomy: A large-scale multicenter cohort study in Japan

BACKGROUND : Gastroesophageal reflux disease (GERD) and reflux esophagitis remain problems after peroral endoscopic myotomy (POEM). This study aimed to elucidate the risk factors and long-term course of reflux esophagitis and symptomatic GERD after POEM. METHODS : This multicenter cohort study involved 14 high volume centers. Overall, 2905 patients with achalasia-related esophageal motility disorders treated with POEM were analyzed for reflux esophagitis, severe reflux esophagitis (Los Angeles classification C or D), and symptomatic GERD. RESULTS : Reflux esophagitis was diagnosed in 1886 patients (64.9 %). Age ≥ 65 years (risk ratio [RR] 0.85), male sex (RR 1.11), posterior myotomy (RR 1.12), esophageal myotomy > 10 cm (RR 1.12), and gastric myotomy > 2 cm (RR 1.17) were independently associated with reflux esophagitis. Severe reflux esophagitis was diagnosed in 219 patients (7.5 %). Age ≥ 65 years (RR 1.72), previous treatments (RR 2.21), Eckardt score ≥ 7 (RR 0.68), sigmoid-type achalasia (RR 1.40), and esophageal myotomy > 10 cm (RR 1.59) were factors associated with severe reflux esophagitis. Proton pump inhibitors (PPIs) were more effective for reflux esophagitis at 5-year follow-up (P = 0.03) than after 1 year (P = 0.08). Symptomatic GERD was present in 458 patients (15.9 %). Symptom duration ≥ 10 years (RR 1.28), achalasia diagnosis (RR 0.68), integrated relaxation pressure ≥ 26 (RR 0.60), and posterior myotomy (RR 0.80) were associated with symptomatic GERD. The incidence of symptomatic GERD was lower at 5-year follow-up compared with that after 1 year (P = 0.04), particularly in PPI users (P < 0.001). CONCLUSIONS : The incidence of severe reflux esophagitis was low after POEM, but excessive myotomy for older patients with previous treatments should be avoided. Early phase symptomatic GERD is non-acid reflux dependent and the natural course is favorable, basically supporting conservative treatment.

Standardized Methods Using EUS-guided Fine-needle Biopsy and a Minimal Medium Creates Three Pancreatic Cancer Organoids

BACKGROUND/AIM

Recently, endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) has been conducted for diagnosing pancreatic ductal adenocarcinoma (PDAC), after which obtained samples were used in organoid cultures. However, no standardized method for PDAC organoid cultures exists. Therefore, to standardize or simplify sample collection and culture methods for PDAC organoids, we performed a floating culture using non-minced specimens obtained by EUS-FNB in a minimal medium, lacking growth factors or inhibitors for pancreatic organoids.

PATIENTS AND METHODS

A total of 38 patients with clinically diagnosed PDAC were enrolled in the study. First, EUS-FNB was conducted using a 22- or 25-gauge biopsy needle. Then, a surplus of samples was collected for organoid formation after rapid on-site cytological evaluations of sample adequacy. Subsequently, the established organoids were compared with clinical data and pathological diagnosis, following periodic observations and evaluations for morphology.

RESULTS

PDAC organoids were successfully created in 24 of the 38 cases (63.2%), including four cases with pathologically inconclusive EUS-FNB results. Afterward, PDAC organoid morphology was classified into ductal, dormant, and adhesive small cluster (ASC) types. Although the ductal and ASC types were seen separately, they were also seen together in other cases, which we named "mixed type".

CONCLUSION

We propose a feasible and straightforward method for establishing organoids, especially for diagnosing PDAC, particularly when the result of EUS-FNB is pathologically inconclusive. Furthermore, PDAC organoids are morphologically classified into three types reported for the first time.

Tissue pad degradation of ultrasonic device may enhance thermal injury and impair its sealing performance in liver surgery

BACKGROUND

Ultrasonic devices are widely used in many surgical fields, including hepatectomy; however, the negative effects of tissue pad degradation of ultrasonic devices, including those in liver surgery, remain unknown. The Harmonic^® 1100 (H-1100) scalpel has advanced heat control technology than previous models, such as the Harmonic^® HD1000i (H-HD1000i). We hypothesized that, because of its advanced temperature-control technology, the H-1100 scalpel would show less tissue pad degradation, resulting in superior sealing performance, compared to that with the H-HD1000i scalpel.

AIM

To elucidate ultrasonic device tissue pad degradation effects on instrument temperature and sealing performance using ex vivo porcine liver/vessel models.

METHODS

Two different harmonic scalpels were used and compared: A newer model, the H-1100 scalpel, and an older model, the H-HD1000i scalpel. Using ex vivo porcine livers, each instrument was activated until the liver parenchyma was dissected. The device temperature (passive jaw temperature) was measured after every 10 consecutive activations, until 300 transections of the porcine liver were performed. Tissue pad degradation was evaluated after 300 activations. Sealing performance was evaluated using excised porcine carotid vessels; vessel sealing speed and frequency of vessel burst pressure below 700 mmHg were determined after 300 transections of porcine liver parenchyma.

RESULTS

The temperature of the H-HD1000i scalpel was approximately 10°C higher than that of the H-1100 scalpel, and gradually increased as the number of activations increased. The median passive jaw temperature of the H-HD1000i scalpel was significantly higher than that of the H-1100 scalpel (73.4°C vs 65.1°C; P < 0.001). After 300 transections of porcine liver parenchyma, less tissue pad degradation was observed with the H-1100 scalpel than with the H-HD1000i scalpel (0.08 mm vs 0.51 mm). The H-1100 scalpel demonstrated faster vessel-sealing speed (4.9 sec. vs 5.1 sec.) and less frequent vessel burst pressure < 700 mmHg (0% vs 40%) after 300 activations than the H-HD1000i scalpel; however, the difference did not reach statistical significance (P = 0.21 and P = 0.09, respectively).

CONCLUSION

In an ex vivo porcine hepatectomy model, the H-1100 scalpel shows lower passive jaw temperature and maintains its sealing performance by avoiding tissue pad degradation compared to that with the H-HD1000i.

Dissection Around the Superior Mesenteric Artery (SMA) Using LigaSure Maryland During Left Posterior Approach for Pancreaticoduodenectomy

R0 resection for pancreatic head cancer without exposing the tumor demands complete resection of “mesopancreas”. In other words, dividing the proximal jejunal artery and vein at their roots of the superior mesenteric artery (SMA) and superior mesenteric vein (SMV) respectively during pancreaticoduodenectomy (PD) is absolutely essential. We present here our standardized dissection procedures around the SMA during the left posterior approach for PD. This procedure is safe and reproducible owing to the secure sealing performance of LigaSure^TM Maryland.

Japanese multicenter prospective study investigating laparoscopic surgery for locally advanced rectal cancer with evaluation of CRM and TME quality (PRODUCT trial)

Aim

In Japan, we have not been able to validate the results of laparoscopic surgery for locally advanced rectal cancer using the universal index “circumferential resection margin (CRM).” Previously, we established a semi‐opened circular specimen processing method and validated its feasibility. In the PRODUCT trial, we aimed to assess CRM in patients with locally advanced rectal cancer who underwent laparoscopic rectal resection.

Methods

This was a multicenter, prospective, observational study. Eligible patients had histologically confirmed rectal adenocarcinoma located at or below 12 cm above the anal verge with clinical stage II or III and were scheduled for laparoscopic or robotic surgery. The primary endpoint was pathological CRM. CRM ≤1 mm was defined as positive.

Results

A total of 303 patients operated on between August 2018 and January 2020 were included in the primary analysis. The number of patients with clinical stage II and III was 139 and 164, respectively. Upfront surgery was performed for 213 patients and neoadjuvant therapy for 90 patients. The median CRM was 4.0 mm (IQR, 2.1‐8.0 mm), and CRM was positive in 26 cases (8.6%). Univariate and multivariate analyses demonstrated that a predicted CRM from the mesorectal fascia of ≤1 mm on MRI was the significant factor for positive CRM (P = .0012 and P = .0045, respectively).

Conclusion

This study showed the quality of laparoscopic rectal resection based on the CRM in Japan. Preoperative MRI is recommended for locally advanced rectal cancer to prevent CRM positivity.

First Search for Exclusive Diphoton Production at High Mass with Tagged Protons in Proton-Proton Collisions at sqrt[s]=13 TeV

A search for exclusive two-photon production via photon exchange in proton-proton collisions, pp→pγγp with intact protons, is presented. The data correspond to an integrated luminosity of 9.4  fb^{-1} collected in 2016 using the CMS and TOTEM detectors at a center-of-mass energy of 13 TeV at the LHC. Events are selected with a diphoton invariant mass above 350 GeV and with both protons intact in the final state, to reduce backgrounds from strong interactions. The events of interest are those where the invariant mass and rapidity calculated from the momentum losses of the forward-moving protons match the mass and rapidity of the central, two-photon system. No events are found that satisfy this condition. Interpreting this result in an effective dimension-8 extension of the standard model, the first limits are set on the two anomalous four-photon coupling parameters. If the other parameter is constrained to its standard model value, the limits at 95% confidence level are |ζ_{1}|<2.9×10^{-13}  GeV^{-4} and |ζ_{2}|<6.0×10^{-13}  GeV^{-4}.

Safety and effectiveness of sling fiber preservation POEM to reduce severe post-procedural erosive esophagitis

BACKGROUND

Peroral endoscopic myotomy (POEM) is standard treatment for achalasia. Gastroesophageal reflux disease (GERD) after POEM has been an important challenge since the early days of POEM implementation. The esophagogastric junction anti-reflux barrier consists of internal lower esophageal sphincter (LES) (i.e., intrinsic muscles of distal esophagus with sling fibers) and external LES (crural diaphragm and phrenoesophageal ligament anchors the distal esophagus to the crural diaphragm). During conventional POEM, the entire internal LES is unintentionally dissected. Preservation of the sling fiber may reduce post-POEM GERD, but its safety and effectiveness have been unclear. In this study, we investigated the safety and effectiveness of sling fiber preservation POEM (SP-POEM) for reducing severe post-procedural erosive esophagitis.

METHODS

We analyzed data of 236 patients who underwent POEM; of these, 203 patients underwent posterior myotomy without (Group 1) or with attempted (Group 2) sling fiber preservation. Group 1 (N = 79; sling fiber excision, N = 68) and Group 2 (N = 90; sling fiber preservation, N = 81) were compared. Post-procedural erosive esophagitis (Los Angeles classification) were assessed and the area (direction and length) of mucosal break was also investigated. The gastroesophageal flap valve was evaluated by Hill's classification.

RESULTS

Severe erosive esophagitis exceeding grade C (Los Angeles classification) occurred in 44.1% of patients (30/68) in Group 1 and in 18.5% of patients (15/81) in Group 2. In mapping of erosive esophagitis, mucosal breaks appeared widely in all directions in Group 1; they tended to be limited in Group 2 (especially in the 2 o'clock direction). Assessment using the Hill's classification showed that the gastroesophageal flap valve was preserved after SP-POEM.

CONCLUSION

SP-POEM is safe and effective, with a success rate of 90%. The rate of severe erosive esophagitis can be decreased by preserving sling fibers.

Crucial Roles of the Assistant Surgeon During Laparoscopic Left Hemihepatectomy

Background

Although left hemihepatectomy has been widely performed via the laparoscopic approach, the roles of the assistant surgeon have not been well-documented so far. We herein present our standardized procedures of laparoscopic left hemihepatectomy without Spiegel’s lobe resection, focusing on the crucial roles of the assistant surgeon.

Methods

During laparoscopic left hemihepatectomy without Spiegel’s lobe resection, countertraction by the assistant surgeon is quite important especially during isolating the left Glissonean pedicle and transecting liver parenchyma. When securing the left hepatic pedicle using the Glissonean approach, the assistant surgeon pushes Segment 4 of the liver cranially and pulls the tape encircling the hepatoduodenal ligament caudally in the opposite way, orthogonal to the direction of the laparoscopic forceps toward the left portal triad. During liver parenchymal transection, the assistant surgeon pulls the hanging tape across the left lobe of the liver in order to provide a wide and stable liver transection plane.

With this standardized technique, nine cases of laparoscopic left hemihepatectomy were performed over the last two years in our department, and the perioperative data were retrospectively analyzed.

Results

The median age of the nine patients was 70 years (range: 58 - 84 years). Most of the patients were males (77.8%). Five of nine patients were diagnosed with colorectal liver metastasis, two with hepatocellular carcinoma (HCC), one with inflammatory pseudotumor, and the other one with hepaticolithiasis. There were no conversions to open surgery. The median operative time and estimated blood loss were 337 minutes (range: 219 - 478 minutes) and 100 ml (range: 41 - 375 ml), respectively. The median length of postoperative hospital stay was nine days (range: 7 - 16 days). Major complications (Clavien-Dindo classification grade III or more) were not encountered in our cohort postoperatively.

Conclusion

We presented here our standardized assistant roles during laparoscopic left hemihepatectomy without Spiegel’s lobe resection, which was revealed to be safe and feasible in our cohort.

Search for low-mass dilepton resonances in Higgs boson decays to four-lepton final states in proton-proton collisions at s = 13 TeV

A search for low-mass dilepton resonances in Higgs boson decays is conducted in the four-lepton final state. The decay is assumed to proceed via a pair of beyond the standard model particles, or one such particle and a Z boson. The search uses proton-proton collision data collected with the CMS detector at the CERN LHC, corresponding to an integrated luminosity of 137 fb - 1 , at a center-of-mass energy s = 13 TeV . No significant deviation from the standard model expectation is observed. Upper limits at 95% confidence level are set on model-independent Higgs boson decay branching fractions. Additionally, limits on dark photon and axion-like particle production, based on two specific models, are reported.

Is laparoscopic liver resection safe for super-elderly patients (aged ≥80)? A propensity score-matched analysis

BACKGROUND/PURPOSE

The safety of laparoscopic liver resection in super-elderly patients with comorbidities is unknown. We used propensity score matching to evaluate the utility and safety of laparoscopic liver resection in super-elderly patients.

METHODS

Two-hundred and five patients who underwent laparoscopic liver resection were retrospectively reviewed. They were classified into two groups based on age: ≥80 years (elderly group, n = 49) and <80 years (control group, n = 156). Propensity score matching (PSM) was performed based on preoperative clinical parameters. The intraoperative and postoperative outcomes were compared.

RESULTS

After matching, 45 patients were included in each group. The intraoperative blood loss was identical between the control and elderly groups (60 vs 60 mL, respectively, P = .588); the frequency of serious postoperative complications (Clavien-Dindo class ≥3, 1/45 vs 1/45, P = 1.00) was also similar. There was no significant difference in terms of the exacerbation of malignancy (22.2% vs 11.1%, P = .258) or other diseases (8.9% vs 22.2%, P = .144). There was no difference in overall survival before and after PSM. However, 5-year overall survival excluding primary cancer-related death showed a difference after PSM (90.7% vs 70.4%; P = .048).

CONCLUSIONS

Laparoscopic liver resection is feasible and safe in super-elderly patients. The long-term prognosis was poor in patients affected by other illnesses compared to the younger population with similar risk profiles, but there was no difference in overall survival.

Endoscopic full‐thickness resection of an esophageal leiomyoma located in close proximity to the azygos vein

Third‐space endoscopic techniques, such as peroral endoscopic tumor resection (POET) and submucosal tunneling endoscopic resection (STER), enable access to deep organs and tissues that have been previously inaccessible with an endoscope. We present a 29‐year‐old man with a submucosal tumor (40 × 25 mm) located at 5 o'clock in the upper thoracic esophagus. Histological diagnosis by endoscopic ultrasound–fine needle aspiration was leiomyoma. Computed tomography showed the azygos vein posterior to the tumor. However, because endoscopic ultrasound revealed space between them, POET was performed. Because the tumor originated from the deep layer of the muscularis propria, full‐thickness resection was performed to achieve R0 resection. The azygos vein arch was seen through the mediastinal space after tumor enucleation. The final histopathological diagnosis was leiomyoma. POET is a potentially revolutionary endoscopic technique that enables full‐thickness resection of nonepithelial lesions. Preoperative computed tomography or endoscopic ultrasound to determine peritumoral anatomy is important to ensure safety. During the procedure, it is important to operate under direct vision, accurately identify the tumor boundary, and dissect along the boundary to avoid damaging the tumor and surrounding structures.

Efficacy and safety of peroral endoscopic myotomy in 100 older patients

BACKGROUND

Peroral endoscopic myotomy (POEM) is a standard treatment for achalasia. Several reports have described the efficacy and safety of POEM for elderly patients, but none has reported the efficacy and safety of POEM in a large number of elderly patients for > 3 years postoperatively. In this study, we examined the safety and outcome of POEM for 3 years postoperatively in 100 elderly patients.

METHODS

One hundred consecutive patients aged > 65 years who underwent POEM from September 2011 to March 2020 were included in this study. In analysis 1, we retrospectively investigated the safety and efficacy of POEM in all patients. In analysis 2, the efficacy and safety of POEM were statistically compared between two groups: the early elderly (65-74 years of age, 55 patients) and late elderly (≥ 75 years of age, 45 patients).

RESULTS

The technical success rate of POEM was 100%. In analysis 1, the 3-month, 1-year, 2-year, and 3-year efficacies of POEM (Eckardt score of ≤ 3) were 100% (92/92 cases), 100% (91/91 cases), 97.8% (88/90 cases), and 100% (92/92 cases), respectively. Procedure-related adverse events occurred in 11% of patients, but none was fatal. Two late elderly patients developed aspiration pneumonia due to delirium and underwent long-term hospitalization. In analysis 2, there were no significant differences in the efficacy and safety of POEM between the two age groups.

CONCLUSIONS

POEM is effective and safe for elderly patients. However, precautions are needed regarding the risk of adverse events associated with delirium when POEM is performed in elderly patients.

Using Z Boson Events to Study Parton-Medium Interactions in Pb-Pb Collisions

The spectra measurements of charged hadrons produced in the shower of a parton originating in the same hard scattering with a leptonically decaying Z boson are reported in lead-lead nuclei (Pb-Pb) and proton-proton (pp) collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV. Both Pb-Pb and pp data sets are recorded by the CMS experiment at the LHC and correspond to an integrated luminosity of 1.7  nb^{-1} and 320  pb^{-1}, respectively. Hadronic collision data with one reconstructed Z boson candidate with the transverse momentum p_{T}>30  GeV/c are analyzed. The Z boson constrains the initial energy and direction of the associated parton. In heavy ion events, azimuthal angular distributions of charged hadrons with respect to the direction of a Z boson are sensitive to modifications of the in-medium parton shower and medium response. compared to reference data from pp interactions, the results for central Pb-Pb collisions indicate a modification of the angular correlations. The measurements of the fragmentation functions and p_{T} spectra of charged particles in Z boson events, which are sensitive to medium modifications of the parton shower longitudinal structure, are also reported. Significant modifications in central Pb-Pb events compared to the pp reference data are also found for these observables.

Relationship between perioperative oncological evaluation and recurrence using circulating tumor DNA with KRAS mutation in patients with colorectal cancer

Background

The detection of circulating tumor DNA (ctDNA) in colorectal cancer (CRC) by liquid biopsy may have prognostic information. In this perioperative study, we evaluate if there is a relationship between mutant allele frequency (MAF) of Kirsten rat sarcoma viral oncogene homolog (KRAS) and tumor recurrence and how that could be useful in the early detection of recurrence.

Methods

Among 304 cases of colorectal cancer surgery, ctDNA was sampled from the perioperative blood of 84 patients with CRC with KRAS mutation (exon 4 p.A146T, exon 4 p.A146V, exon 2 p.G12A, exon 2 p.G12C, exon 2 p.G12D, exon 2 p.G12S, exon 2 p.G12V, exon 2 p.G13D, exon 3 p.Q61H) and analyzed using the digital polymerase chain reaction system. The median observation period was 26 months.

Results

Although the relationship between the perioperative MAF of KRAS and recurrence was not proved, tumor diameter, tumor depth, and stage were correlated with the preoperative MAF of KRAS (p = 0.034, p = 0.002, p = 0.008). However, tumor diameter, tumor depth, and stage did not correlate with MAF of KRAS at postoperative day 30.

Conclusions

In this study, pathological tumor size, tumor depth, and stage were correlated with preoperative MAF of KRAS, but it was unreliable to predict recurrence by detection of ctDNA with KRAS mutation in the perioperative period of colorectal surgery.

Search for strongly interacting massive particles generating trackless jets in proton-proton collisions at s = 13 TeV

A search for dark matter in the form of strongly interacting massive particles (SIMPs) using the CMS detector at the LHC is presented. The SIMPs would be produced in pairs that manifest themselves as pairs of jets without tracks. The energy fraction of jets carried by charged particles is used as a key discriminator to suppress efficiently the large multijet background, and the remaining background is estimated directly from data. The search is performed using proton-proton collision data corresponding to an integrated luminosity of 16.1 fb - 1 , collected with the CMS detector in 2016. No significant excess of events is observed above the expected background. For the simplified dark matter model under consideration, SIMPs with masses up to 100 GeV are excluded and further sensitivity is explored towards higher masses.

Gallbladder Intramucosal Carcinoma Arising in a Cholesterol Polyp: A Case Report

Cholesterol polyp is the most common benign disease of gallbladder polyps, and is considered not to be the origin of malignancy. Herein, we report a rare case of a well-differentiated adenocarcinoma arising in a gallbladder cholesterol polyp. A pedunculated mulberry-like gallbladder polyp diagnosed with a cholesterol polyp preoperatively consisted of two distinct components macroscopically: a yellow-whitish lobulated lesion and a brownish irregular lesion. Microscopically, the former revealed to be a cholesterol polyp, but the latter demonstrated a well-differentiated adenocarcinoma. Even if imaging findings suggest a gallbladder cholesterol polyp, it is important to keep in mind that carcinoma can coexist like our case.

Pebbles and sand on asteroid (162173) Ryugu: In situ observation and particles returned to Earth

The Hayabusa2 spacecraft investigated the C-type (carbonaceous) asteroid (162173) Ryugu. The mission performed two landing operations to collect samples of surface and subsurface material, the latter exposed by an artificial impact. We present images of the second touchdown site, finding that ejecta from the impact crater was present at the sample location. Surface pebbles at both landing sites show morphological variations ranging from rugged to smooth, similar to Ryugu's boulders, and shapes from quasi-spherical to flattened. The samples were returned to Earth on 6 December 2020. We describe the morphology of >5 grams of returned pebbles and sand. Their diverse color, shape, and structure are consistent with the observed materials of Ryugu; we conclude that they are a representative sample of the asteroid.

Precise Measurement of Differential Cross Sections of the Σ^{-}p→Λn Reaction in Momentum Range 470-650 MeV/c

The differential cross sections of the Σ^{-}p→Λn reaction were measured accurately for the Σ^{-} momentum (p_{Σ}) ranging from 470 to 650  MeV/c at the J-PARC Hadron Experimental Facility. Precise angular information about the Σ^{-}p→Λn reaction was obtained for the first time by detecting approximately 100 reaction events at each angular step of Δcosθ=0.1. The obtained differential cross sections show a slightly forward-peaking structure in the measured momentum regions. The cross sections integrated for -0.7≤cosθ≤1.0 were obtained as 22.5±0.68 [statistical error(stat.)] ±0.65 [systematic error(syst.)] mb and 15.8±0.83(stat)±0.52(syst)  mb for 470<p_{Σ}(MeV/c)<550 and 550<p_{Σ}(MeV/c)<650, respectively. These results show a drastic improvement compared with past measurements of the hyperon-proton scattering experiments. They will play essential roles in updating the theoretical models of the baryon-baryon interactions.