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Background Endoscopic submucosal dissection (ESD) in colorectal lesions is technically demanding and a significant rate of noncurative procedures is expected. We aimed to assess the rate of residual lesions after a noncurative ESD for colorectal cancer (CRC) and to establish predictive scores to be applied in the clinical setting. Methods Retrospective multicenter analysis of consecutive colorectal ESDs. Patients with noncurative ESDs performed for the treatment of CRC lesions submitted to complementary surgery or with at least one follow-up endoscopy were included. Results From 2255 colorectal ESDs, 381 (17 %) were noncurative, and 135 of these were performed in CRC lesions. A residual lesion was observed in 24 patients (18 %). Surgery was performed in 96 patients and 76 (79 %) had no residual lesion in the colorectal wall or in the lymph nodes. The residual lesion rate for sm1 cancers was 0 %, and for > sm1 cancers was also 0 % if no other risk factors were present. Independent risk factors for lymph node metastasis were poor differentiation and lymphatic permeation (NC-Lymph score). Risk factors for the presence of a residual lesion in the wall were piecemeal resection, poor differentiation, and positive/indeterminate vertical margin (NC-Wall score). Conclusions Lymphatic permeation or poor differentiation warrant surgery owing to their high risk of lymph node metastasis, mainly in > sm1 cancers. In the remaining cases, en bloc and R0 resections resulted in a low risk of residual lesions in the wall. Our scores can be a useful tool for the management of patients who undergo noncurative colorectal ESDs.

Large slope instability processes result from a complex interaction among different geological, geomorphological and climatic factors. A complex multidisciplinary approach is thus necessary to understand their behavior and develop modeling predictive tools. This work suggests a multi coupling method to predict stability and velocity of a landslide, giving critical values for measurable variables (i.e., piezometric level) up to which remediation actions can be deployed. The aim is to define a time‐dependent stability criterion that links the external forcing of a landslide with its internal response through a thermo-poro-mechanical mathematical model.The presented model is based on the assumption that most of the landslide deformation is concentrated on a basal shear band representing the sliding surface: the landslide body is deemed as a rigid block sliding on a visco-plastic shear band with thermal softening and velocity hardening. When the landslide moves, it causes friction with mechanical dissipation that raises the basal temperature and reduces the shearing resistance of the shear-band material. This process can continue up to the point when the friction coefficient decreases uncontrollably due to a thermal runaway instability and the system become unstable, even without changes in the external factors.The model is applied to the Ruinon Landslide located in the Central Italian Alps (upper Valtellina region). It represents one of the most active cases in the alpine region, with a main sliding surface located at a depth of approximately 70 m, for a total estimated volume of about 20 Mm3 threatening the national road SS300 that travels through the valley bottom. On the base of the available in situ monitoring data (Piezometers, Ground-Based Interferometric Radar), velocity–time curves correlate with the piezometric level trend, suggesting a key role of pore pressure as an accelerating factor for the landslide.The workflow of the analysis involved different steps. A preliminary 3D FEM numerical analysis was performed to provide the stress-strain distribution along the slope. Then, to define the thermo-poro-mechanical behavior of the sliding surface and to calibrate the mathematical model, triaxial compression tests with thermal control were performed on rock samples representative of the shear band. The pore pressure data from in situ piezometers were introduced as input-data and the landslide basal temperature was calculated. Finally, the strain rate was simulated by the model and a process of validation was applied using field displacement histories recorded by the landslide monitoring system.The outputs of the model well simulate the landslide velocity, reproducing the sliding behavior and its relationship with pore pressure. The developed time dependent stability criterion represents an innovative physics-based tool for analyze landslide evolution leading to early-warning and remediation strategies, that accounts for thermal and velocity sensitivity of shear band materials, as well as the effect of pore pressure in promoting the evolution of different creep stages. The validated model can be also used as a predictive tool, to forecast the behavior of landslides and establish a physically based early warning strategy taking into account future climate scenarios.

The Piuro 1618 landslide represents a well-known case history of a large Alpine landslide. It destroyed the ancient village of Piuro (Italian Bregaglia Valley), renowned as an important trading center between the Mediterranean region and Northern Europe. The event had a significant impact among communities of all Alpine regions and was well documented by chronicles and paintings during subsequent decades. However, some aspects, such as the geometry reconstruction of the landslide body, the location of the landslide scarp, and its dynamics, remained undefined in previous studies, and a geomechanical characterization of the failure area is completely missing. Using field and laboratory analysis followed by stress–strain numerical modelling, this work develops a 3D conceptual geomechanical model of the slope considering its complex geological framework. The aim is to back-analyze the 1618 event, defining predisposing and triggering factors of the sliding event, and providing verifications on the geometry and location of the failure scar, as well as on the landslide dynamics. A coupled hydro-mechanical analysis with a 3D numerical approach is presented, assuming a rainfall scenario as a possible triggering factor. Simulated displacement and the development of a deep region of shear strain localization at a depth roughly corresponding to that of the detected Piuro sliding surface, allow us to highlight the mechanical role of geological elements outcropping along the slope and to validate the proposed scenario as a likely triggering factor for the 1618 event.