Stereotactic navigation using registration based on intra-abdominal landmarks in robotic-assisted lateral pelvic lymph node dissection.

BACKGROUND: We carried out robot-assisted lateral pelvic lymph node dissection (LPLND) for rectal cancer with a stereotactic navigation system. The purpose of this study was to evaluate the accuracy and feasibility of the system. METHODS: We constructed a navigation system based on the Polaris Spectra optical tracking device (Northern Digital Inc., Canada) and the open-source software 3D Slicer (version 3.8.1; http://www.slicer.org ). We used the landmark-based registration method for patient-to-image registration. Body surface landmarks and intra-abdominal landmarks were used. We evaluated the time required for registration and target registration error (TRE; the distance between corresponding points after registration) for the root of the superior gluteal artery the root of the obturator or superior vesical artery, and the obturator foramen during minimally invasive LPLND for rectal cancer. Five patients who had LPLND for rectal cancer at the University of Tokyo Hospital between September 2020 and May 2021 were enrolled. RESULTS: The mean time required for registration was 49 s with the body surface landmarks and 88 s with the intra-abdominal landmarks. The mean TRE improved markedly when the registration was performed using intra-abdominal landmarks. The mean TRE of the root of the superior gluteal artery, the root of the obturator or superior vesical artery, and the obturator foramen were 55.8 mm, 53.4 mm, and 55.2 mm with the body surface landmarks and 11.8 mm, 10.0 mm, and 12.6 mm with the intra-abdominal landmarks, respectively. There were no adverse events related to the registration process. CONCLUSIONS: When stereotactic navigation systems are used for minimally invasive LPLND, the use of intra-abdominal landmarks for registration is feasible and may allow simpler and more accurate navigation than the use of body surface landmarks.

Nanoscale defect evaluation framework combining real-time transmission electron microscopy and integrated machine learning-particle filter estimation.

Observation of dynamic processes by transmission electron microscopy (TEM) is an attractive technique to experimentally analyze materials' nanoscale phenomena and understand the microstructure-properties relationships in nanoscale. Even if spatial and temporal resolutions of real-time TEM increase significantly, it is still difficult to say that the researchers quantitatively evaluate the dynamic behavior of defects. Images in TEM video are a two-dimensional projection of three-dimensional space phenomena, thus missing information must be existed that makes image's uniquely accurate interpretation challenging. Therefore, even though they are still a clustering high-dimensional data and can be compressed to two-dimensional, conventional statistical methods for analyzing images may not be powerful enough to track nanoscale behavior by removing various artifacts associated with experiment; and automated and unbiased processing tools for such big-data are becoming mission-critical to discover knowledge about unforeseen behavior. We have developed a method to quantitative image analysis framework to resolve these problems, in which machine learning and particle filter estimation are uniquely combined. The quantitative and automated measurement of the dislocation velocity in an Fe-31Mn-3Al-3Si autunitic steel subjected to the tensile deformation was performed to validate the framework, and an intermittent motion of the dislocations was quantitatively analyzed. The framework is successfully classifying, identifying and tracking nanoscale objects; these are not able to be accurately implemented by the conventional mean-path based analysis.

A randomized, controlled trial of once-weekly teriparatide injection versus alendronate in patients at high risk of osteoporotic fracture: primary results of the Japanese Osteoporosis Intervention Trial-05.

In this randomized, controlled trial, treatment with once-weekly subcutaneous injection of teriparatide for 72 weeks was found to be associated with a significant reduction in the incidence of morphometric vertebral fractures compared with alendronate in women with primary osteoporosis who were at high risk of fracture. INTRODUCTION: To determine whether the anti-fracture efficacy of teriparatide is superior to that of alendronate, a prospective, randomized, open-label, blinded-endpoint trial was performed. METHODS: Japanese women aged at least 75 years were eligible for the study if they had primary osteoporosis and were at high risk of fracture. Patients were randomly assigned in a 1:1 ratio to receive sequential therapy (once-weekly subcutaneous injection of teriparatide 56.5 µg for 72 weeks followed by alendronate for 48 weeks) or monotherapy with alendronate for 120 weeks. The primary endpoint was the incidence of morphometric vertebral fractures at 72 weeks (at the end of teriparatide treatment). RESULTS: Between October 2014 and December 2017, 1011 patients (505 in the teriparatide group and 506 in the alendronate group) were enrolled. Of these, 778 patients (351 and 427, respectively) were included in the primary analysis. The incidence of morphometric vertebral fractures was significantly lower in the teriparatide group (56 per 419.9 person-years, annual incidence rate 0.1334) than in the alendronate group (96 per 553.6 person-years, annual incidence rate 0.1734), with a rate ratio of 0.78 (95% confidence interval 0.61 to 0.99, P = 0.04). In both groups, adverse events were most frequently reported in the following system organ classes: infections and infestations, gastrointestinal disorders, and musculoskeletal and connective tissue disorders. CONCLUSION: Once-weekly subcutaneous injection of teriparatide significantly reduced the incidence of morphometric vertebral fractures compared with alendronate in women with primary osteoporosis who were at high risk of fracture. TRIAL REGISTRATION: jRCTs031180235 and UMIN000015573, March 12, 2019.

Classification of the colonic splenic flexure based on three-dimensional CT analysis.

BACKGROUND: Mobilization of the splenic flexure can be a challenging surgical step in colorectal surgery. This study aimed to classify the splenic flexure based on the three-dimensional (3D) coordinates of the splenic hilum and left renal hilum. This classification was used to compare splenic flexure mobilization during colorectal resection. METHODS: CT images of patients with colorectal cancer treated between April 2018 and December 2019 were analysed retrospectively. 3D mutual positioning of the splenic flexure from the ligament of Treitz to the splenic hilum or the left renal hilum was used to classify patients into three groups using cluster analysis. The difference in the procedure time between groups was also analysed in a subset of patients undergoing laparoscopic colectomy with complete splenic flexure mobilization. RESULTS: Of 515 patients reviewed, 319 with colorectal cancers were included in the study and categorized based on the 3D coordinates of the splenic hilum and left renal hilum as caudal (100 patients), cranial (118) and lateral (101) positions. Male sex (P < 0.001), older age (P = 0.004) and increased bodyweight (P = 0.043) were independent characteristics of the lateral group in multiple logistic regression analysis. Thirty-four patients underwent complete splenic flexure mobilization during the study period; this took significantly longer (mean 78.7 min) in the lateral group than in the caudal and cranial groups (41.8 and 43.2 min respectively; P = 0.006). CONCLUSION: Locating the splenic flexure using 3D coordinates could be helpful in predicting a longer duration for mobilization of the splenic flexure.

Utility of computed tomography and 18 F-fluorodeoxyglucose with positron emission tomography/computed tomography for distinguishing appendiceal mucocele caused by mucinous adenocarcinoma from other pathologies.

AIM: Differentiating appendiceal mucocele with mucinous adenocarcinoma from other pathologies before surgery is difficult. The objective of this study was to evaluate the utility of CT and 18 F-fluorodeoxyglucose (FDG) with positron emission tomography (PET)/CT for differentiating mucinous adenocarcinoma of appendiceal mucocele from other pathologies. METHOD: The study included 25 patients who underwent surgery for clinically diagnosed appendiceal mucoceles detected on CT at the University of Tokyo Hospital. Among these patients, 19 underwent FDG-PET/CT preoperatively. We compared features of the CT imaging findings and maximum standard uptake values (SUVmax ) detected by FDG-PET/CT between mucocele with mucinous adenocarcinoma and other pathologies. RESULTS: A total of 13 men (52%) and 12 women (48%) were included in this study, with a median age of 65 years (range 34-83). There were six patients (24%) with pathologically confirmed mucinous adenocarcinoma, 15 patients (60%) with appendiceal mucinous neoplasm and four patients (16%) with simple mucocele caused by chronic inflammation. On the CT findings, wall irregularity was the only significant feature for the two groups in this study (83.3% vs 0.0%, P < 0.01). There was a significant difference in the SUVmax levels on PET/CT between the two groups (100.0% vs 20.0%, P < 0.01). CONCLUSION: Distinguishing between mucocele with mucinous adenocarcinoma and other pathologies using imaging modalities is challenging. Our results suggest that wall irregularity on CT and elevated SUVmax on PET/CT are useful factors that can be employed for such discrimination.

Transfer of orbital angular momentum of light to plasmonic excitations in metamaterials.

The emergence of the vortex beam with orbital angular momentum (OAM) has provided intriguing possibilities to induce optical transitions beyond the framework of the electric dipole interaction. The uniqueness stems from the OAM transfer from light to material, as demonstrated in electronic transitions in atomic systems. In this study, we report on the OAM transfer to electrons in solid-state systems, which has been elusive to date. Using metamaterials (periodically textured metallic disks), we show that multipolar modes of the surface electromagnetic excitations (so-called spoof localized surface plasmons) are selectively induced by the terahertz vortex beam. Our results reveal selection rules governed by the conservation of the total angular momentum, which is confirmed by numerical simulations. The efficient transfer of light's OAM to elementary excitations in solid-state systems at room temperature opens up new possibilities of OAM manipulation.

Possible Lightest Ξ Hypernucleus with Modern ΞN Interactions.

Experimental evidence exists that the Ξ-nucleus interaction is attractive. We search for NNΞ and NNNΞ bound systems on the basis of the AV8 NN potential combined with either a phenomenological Nijmegen ΞN potential or a first principles HAL QCD ΞN potential. The binding energies of the three-body and four-body systems (below the d+Ξ and ^{3}H/^{3}He+Ξ thresholds, respectively) are calculated by a high precision variational approach, the Gaussian expansion method. Although the two ΞN potentials have significantly different isospin (T) and spin (S) dependence, the NNNΞ system with quantum numbers (T=0, J^{π}=1^{+}) appears to be bound (one deep for Nijmegen and one shallow for HAL QCD) below the ^{3}H/^{3}He+Ξ threshold. Experimental implications for such a state are discussed.

Effects of preceding endoscopic treatment on laparoscopic surgery for early rectal cancer.

AIM: Endoscopic treatment for rectal cancer, such as endoscopic mucosal resection and endoscopic submucosal dissection, causes inflammation, oedema and fibrosis in the surrounding tissue. However, little is known about the effect of these endoscopic therapies on salvage laparoscopic rectal surgery. The objective of this retrospective cohort study was to analyse the effect of preceding endoscopic treatment on the outcomes of laparoscopic surgery for rectal cancer. METHOD: We analysed 53 patients who underwent laparoscopic surgery for rectal cancer with clinical Tis or T1 at our department between May 2011 and June 2019. Data from 30 patients who underwent laparoscopic surgery after preceding endoscopic treatment (Group E + S) were compared with those of 23 patients who underwent laparoscopic surgery alone (Group S). RESULTS: There was no significant difference between the groups with respect to preoperative details. The mean operative time tended to be longer in Group E + S, and the volume of intra-operative blood loss was greater in Group E + S than in Group S (median 63 ml vs 10 ml, P = 0.049). There were no significant differences between the groups in other surgical parameters or oncological outcomes. CONCLUSION: Laparoscopic surgery after endoscopic treatment for rectal cancer may be difficult due to an increased risk of intra-operative bleeding. Long-term prognosis after surgery was not affected by preceding endoscopic treatment in rectal cancer.

Hepatocellular carcinoma tumour burden score to stratify prognosis after resection.

BACKGROUND: Although the Barcelona Clinic Liver Cancer (BCLC) staging system has been largely adopted in clinical practice, recent studies have emphasized the need for further refinement and subclassification of this system. METHODS: Patients who underwent hepatectomy with curative intent for BCLC-0, -A or -B hepatocellular carcinoma (HCC) between 2000 and 2017 were identified using a multi-institutional database. The tumour burden score (TBS) was calculated, and overall survival (OS) was examined in relation to TBS and BCLC stage. RESULTS: Among 1053 patients, 63 (6·0 per cent) had BCLC-0, 826 (78·4 per cent) BCLC-A and 164 (15·6 per cent) had BCLC-B HCC. OS worsened incrementally with higher TBS (5-year OS 77·9, 61 and 39 per cent for low, medium and high TBS respectively; P < 0·001). No differences in OS were noted among patients with similar TBS, irrespective of BCLC stage (61·6 versus 58·9 per cent for BCLC-A/medium TBS versus BCLC-B/medium TBS, P = 0·930; 45 versus 13 per cent for BCLC-A/high TBS versus BCLC-B/high TBS, P = 0·175). Patients with BCLC-B HCC and a medium TBS had better OS than those with BCLC-A disease and a high TBS (58·9 versus 45 per cent; P = 0·005). On multivariable analysis, TBS remained associated with OS among patients with BCLC-A (medium TBS: hazard ratio (HR) 2·07, 95 per cent c.i. 1·42 to 3·02, P < 0·001; high TBS: HR 4·05, 2·40 to 6·82, P < 0·001) and BCLC-B (high TBS: HR 3·85, 2·03 to 7·30; P < 0·001) HCC. TBS could also stratify prognosis among patients in an external validation cohort (5-year OS 79, 51·2 and 28 per cent for low, medium and high TBS respectively; P = 0·010). CONCLUSION: The prognosis of patients with HCC varied according to the BCLC stage but was largely dependent on the TBS.

ANTECEDENTES: Aunque el sistema de estadificación del Barcelona Clinic Liver Cancer (BCLC) ha sido adoptado en gran medida en la práctica clínica, estudios recientes han enfatizado la necesidad de un mayor refinamiento y subclasificación del sistema BCLC. MÉTODOS: Los pacientes con carcinoma hepatocelular (hepatocellular cancer, HCC) BCLC-0, A y B que se sometieron a una hepatectomía con intención curativa entre 2000 y 2017 fueron identificados utilizando una base de datos multi-institucional. Se calculó la puntuación de carga tumoral (tumour burden score, TBS) y se examinó la supervivencia global (overall survival, OS) en relación con la TBS y los estadios BCLC. RESULTADOS: En la serie de 1.053 pacientes, 63 (6%) tenían HCC BCLC-0, 826 (78,4%) HCC BCLC-A y 164 (15,6%) HCC BCLC-B. La OS disminuyó de forma incremental en función de la mayor TBS (OS a 5 años; TBS baja: 77,9% versus TBS media: 61% versus TBS alta: 39%, P < 0,001). No se observaron diferencias en la OS entre pacientes con una puntuación TBS similar, independientemente del estadio BCLC (BCLC-A/TBS media: 61,6% versus BCLC-B/TBS media: 58,9%, P = 0,93; BCLC-A/TBS alta: 45,1% versus BCLC-B/TBS alta: 12,8%, P = 0,175). Los pacientes con BCLC-B/TBS media tuvieron una mejor OS que los pacientes con BCLC-A/TBS alta (58,9% versus 45,1%, P = 0,005). En el análisis multivariable, la TBS se mantuvo asociada a la OS en el caso de BCLC-A (TBS media: cociente de riesgos instantáneos, hazard ratio, HR = 2,07, i.c. del 95%: 1,42-3,02, P < 0,001; TBS alta: HR = 4,05, i.c. del 95%: 2,40-6,82, P < 0,001) y BCLC-B pacientes (TBS alta: HR = 3,85, i.c. del 95%: 2,03-7,30, P < 0,001). La TBS también pudo estratificar el pronóstico entre pacientes en una cohorte de validación externa (OS a 5 años; TBS baja: 78,7% versus TBS media: 51,2% versus TBS alta: 27,6%, P = 0,01). CONCLUSIÓN: El pronóstico de los pacientes con HCC varió según el estadio BCLC, pero dependió en gran medida de la TBS.

Incidence of and risk factors for lymphocele formation after lateral pelvic lymph node dissection for rectal cancer: a retrospective study.

AIM: Pelvic lymphocele is a common complication that develops after pelvic lymph node dissection. The incidence of pelvic lymphocele formation has been reported to be 10.5-51% after gynaecological or urological procedures. However, no evidence has been reported thus far with regard to the development of pelvic lymphocele following lateral pelvic lymph node dissection (LPND) for low rectal cancer. The aim of this study was to investigate the incidence of and risk factors for lymphocele formation after LPND for low rectal cancer and to examine its clinical management. METHOD: We retrospectively analysed the incidence of and risk factors for pelvic lymphocele formation after LPND for rectal cancer in our hospital between January 2012 and December 2017. We also compared the size of the lymphocele between asymptomatic and symptomatic patients by using CT volumetry and examined its clinical management. RESULTS: A total of 30 out of 98 patients (30.8%) developed pelvic lymphocele after rectal LPND. The number of resected nodes was significantly higher in patients with a pelvic lymphocele (P < 0.01). The median volume was significantly higher in patients with symptomatic pelvic lymphocele (P = 0.011). Among the nine symptomatic patients, two underwent CT-guided drainage, one underwent transurethral ureteral stent placement and one underwent laparoscopic marsupialization. CONCLUSION: It is essential to keep in mind the possibility of pelvic lymphocele formation during follow-up of patients who undergo LPND, and to consider an appropriate treatment when these patients are symptomatic.

Vascular anatomy of the splenic flexure, focusing on the accessory middle colic artery and vein.

AIM: Recently, the accessory middle colic artery (AMCA) has been recognized as the vessel that supplies blood to the splenic flexure. However, the positional relationship between the AMCA and inferior mesenteric vein (IMV) has not been evaluated. Herein, we aimed to evaluate the anatomy of the AMCA and the splenic flexure vein (SFV). METHOD: Two hundred and five patients with colorectal cancer who underwent enhanced CT preoperatively were enrolled in the present study. The locations of the AMCA and IMV were evaluated, focusing on the positional relationship between the vessels and pancreas - below the pancreas or to the dorsal side of the pancreas. RESULTS: The AMCA was observed in 74 (36.1%) patients whereas the SFV was found in 177 (86.3%) patients. The left colic artery (LCA) was the major artery accompanying the SFV in 87 (42.4%) of patients. The AMCA accompanied the SFV in 65 (32.7%) patients. In 15 (7.8%) patients, no artery accompanied the SFV. The origin of the AMCA was located on the dorsal side of the pancreas in 15 (20.3%) of these 74 patients. Similarly, the destination of the IMV was located on the dorsal side of the pancreas in 65 (31.7%) of patients. CONCLUSION: The SFV was observed in most patients, and the LCA or AMCA was the common accompanying artery. In some patients these vessels were located on the dorsal side of the pancreas and not below it. Preoperative evaluation of this anatomy may be beneficial for lymph node dissection during left-sided hemicolectomy.

Images from the surface of asteroid Ryugu show rocks similar to carbonaceous chondrite meteorites.

The near-Earth asteroid (162173) Ryugu is a 900-m-diameter dark object expected to contain primordial material from the solar nebula. The Mobile Asteroid Surface Scout (MASCOT) landed on Ryugu's surface on 3 October 2018. We present images from the MASCOT camera (MASCam) taken during the descent and while on the surface. The surface is covered by decimeter- to meter-sized rocks, with no deposits of fine-grained material. Rocks appear either bright, with smooth faces and sharp edges, or dark, with a cauliflower-like, crumbly surface. Close-up images of a rock of the latter type reveal a dark matrix with small, bright, spectrally different inclusions, implying that it did not experience extensive aqueous alteration. The inclusions appear similar to those in carbonaceous chondrite meteorites.

Obstruction is associated with perineural invasion in T3/T4 colon cancer.

AIM: Perineural invasion (PNI) is a risk factor for recurrence and metastasis and consequently leads to decreased survival in patients with various malignancies. Recent studies showed that stent placement in obstructive colon cancer increases the frequency of PNI. We hypothesized that mechanical stress including obstruction itself may be associated with PNI. METHOD: We retrospectively reviewed 496 patients with pathological T3 or T4 colon cancer who did not receive preoperative treatment. Data were collected from medical charts and pathological findings. The relationships between PNI and other clinicopathological factors were analysed using univariate and multivariate analyses. RESULTS: PNI was observed in 239 (48%) patients. Obstruction was markedly more frequent in PNI-positive cancer (39%) than in PNI-negative cancer (24%, P = 0.0003). Multivariate analyses identified obstruction as one of the significant factors associated with PNI (OR 1.68, P = 0.028). Moreover, in 414 patients without distant metastasis who underwent complete resection, PNI was an independent factor associated with poor recurrence-free survival (hazard ratio 2.35, P = 0.003). The coexistence of PNI and obstruction resulted in greater decreases in recurrence-free survival than PNI-negative and/or non-obstructive cases. CONCLUSION: Our results suggest that obstruction is associated with PNI and consequently contributes to an increased postoperative recurrence in colon cancer.

Mild to Moderate Intrapulmonary Shunting in Pediatric Liver Transplantation: Is Screening Necessary?

BACKGROUND: Despite reported associations between intrapulmonary vascular shunting (IPVS) and morbidity and mortality in pediatric liver transplantation (LT), there are no guidelines for screening. OBJECTIVE: To investigate IPVS before and after pediatric LT. METHODS: Retrospective records review of all pediatric LT (n = 370) from 2005 to 2015 at a single institute in Japan. All children with cirrhosis and clinical suspicion of IPVS without cardiac or pulmonary conditions were included. 99mTechnetium labelled macroaggregated albumin (99mTcMAA) scans were performed before and after LT. The severity of IPVS was graded using shunt ratios. RESULTS: Twenty-four children fulfilled inclusion criteria and underwent Tc99MAA scans. All revealed mild (<20%) to moderate (20%-40%) grades of IPVS. Following LT, the mean shunt ratio regressed from 20.69 ± 6.26% to 15.1 ± 3.4% (P = .06). The median (range) follow-up was 17 (4-85) months. Mortality was zero. The incidence of portal vein thrombosis (4.2%) biliary strictures (12.5%) and graft loss (4.1%) in the study group was not statistically significant compared to the remainder of the 370 transplants (3.2%, 9.4% and 3%, respectively). Sub-group analysis revealed hepatopulmonary syndrome (HPS) in 2 out of 24 children. The mean shunt ratios before and after LT were 39.2 ± 0.77% and 16.2 ± 8.5%, respectively (P = .08). There was 1 complication (intra-abdominal abscess). CONCLUSIONS: HPS is less likely in mild to moderate IPVS. LT may achieve comparable results when performed in the presence of mild to moderate IPVS.

Three-dimensional localization spectroscopy of individual nuclear spins with sub-Angstrom resolution.

Nuclear magnetic resonance (NMR) spectroscopy is a powerful method for analyzing the chemical composition and molecular structure of materials. At the nanometer scale, NMR has the prospect of mapping the atomic-scale structure of individual molecules, provided a method that can sensitively detect single nuclei and measure inter-atomic distances. Here, we report on precise localization spectroscopy experiments of individual 13C nuclear spins near the central electronic sensor spin of a nitrogen-vacancy (NV) center in a diamond chip. By detecting the nuclear free precession signals in rapidly switchable external magnetic fields, we retrieve the three-dimensional spatial coordinates of the nuclear spins with sub-Angstrom resolution and for distances beyond 10 Å. We further show that the Fermi contact contribution can be constrained by measuring the nuclear g-factor enhancement. The presented method will be useful for mapping atomic positions in single molecules, an ambitious yet important goal of nanoscale nuclear magnetic resonance spectroscopy.

Evaluation of the vascular anatomy of the left-sided colon focused on the accessory middle colic artery: a single-centre study of 734 patients.

AIM: Surgery for colorectal cancer located in the splenic flexure is difficult to perform because of the complex anatomy. Recently, in addition to the middle colic artery and left colic artery (LCA), the accessory middle colic artery (AMCA) has been recognized as a feeding artery for the left-sided colon. This study aimed to evaluate the vascular anatomy of the splenic flexure focusing on the AMCA in a large number of patients. METHOD: A total of 734 patients who underwent CT before surgery for colorectal cancer were enrolled. We retrospectively evaluated the vascular anatomy using both two- and three-dimensional CT angiography. RESULTS: The AMCA existed in 36.4% of the cases (n = 267). In many cases, it originated from the superior mesenteric artery (n = 228, 85.4%). The AMCA had a common trunk with the transverse pancreatic artery in 54 patients (20.2%). The frequency of the presence of the AMCA was associated with the branching pattern of the LCA, and was more frequent when the LCA was absent (P < 0.001). CONCLUSION: The presence of the AMCA is not rare and the AMCA has some branching patterns; therefore, recognizing it preoperatively and intra-operatively is important, being especially careful when the LCA is absent.