Diagnostic laparoscopy: indications and benefits

Force-based control strategy for a collaborative robotic camera holder in laparoscopic surgery using pivoting motion

Introduction: Laparoscopic surgery often relies on a fixed Remote Center of Motion (RCM) for robot mobility control, which assumes that the patient's abdominal walls are immobile. However, this assumption is inaccurate, especially in collaborative surgical environments. In this paper, we present a force-based strategy for the mobility of a robotic camera-holder system for laparoscopic surgery based on a pivoting motion. This strategy re-conceptualizes the conventional mobility control paradigm of surgical robotics. Methods: The proposed strategy involves direct control of the Tool Center Point's (TCP) position and orientation without any constraints associated with the spatial position of the incision. It is based on pivoting motions to minimize contact forces between the abdominal walls and the laparoscope. The control directly relates the measured force and angular velocity of the laparoscope, resulting in the reallocation of the trocar, whose position becomes a consequence of the natural accommodation allowed by this pivoting. Results: The effectiveness and safety of the proposed control were evaluated through a series of experiments. The experiments showed that the control was able to minimize an external force of 9 N to ±0.2 N in 0.7 s and reduce it to 2 N in just 0.3 s. Furthermore, the camera was able to track a region of interest by displacing the TCP as desired, leveraging the strategy's property that dynamically constrains its orientation. Discussion: The proposed control strategy has proven to be effective minimizing the risk caused by sudden high forces resulting from accidents and maintaining the field of view despite any movements in the surgical environment, such as physiological movements of the patient or undesired movements of other surgical instruments. This control strategy can be implemented for laparoscopic robots without mechanical RCMs, as well as commercial collaborative robots, thereby improving the safety of surgical interventions in collaborative environments.

Staging Early Esophageal Cancer

Staging esophageal cancer provides a standardized measure of the extent of disease that can be used to inform decisions about therapy and guide prognosis. For esophageal cancer, the treatment pathways vary greatly depending on stage of disease, and accurate staging is therefore crucial in ensuring the optimal therapy for each patient. For early esophageal cancer (T1 lesions), endoscopic resection can be curative and simultaneously gives accurate staging of depth of invasion. For tumors invading the submucosa or more advanced disease, comprehensive investigation is required to accurately stage the tumor and assess suitability for curative resection. A combined imaging approach of computed tomography (CT), positron emission tomography (PET), and endoscopic ultrasound (EUS) offers complementary diagnostic information and gives the greatest chance of accurate staging. Staging laparoscopy can identify peritoneal disease and small superficial liver lesions that could be missed on CT or PET, and alters management in up to 20 % of patients. Optical diagnostic techniques offer the prospect of further extending the possibilities of endoscopic staging in real time. Optical coherence tomography can image superficial lesions and could provide information on depth of invasion for these lesions. Real-time lymph node analysis using optical diagnostics such as Raman spectroscopy could be used to support immediate endoscopic therapy without waiting for results of cytology or further investigations.

Making the Difference in Exotic Animal Practice: The Value of Endoscopy

The definitive diagnosis has often been elusive in exotic pet medicine, and its absence has been, and continues to be, the source of much client anguish and practitioner frustration. To reach a definitive diagnosis, demonstration of a pathologic response and the etiologic agent are required. This article demonstrates why such an approach is necessary and how it can be readily achieved in practice using endoscopy.

Clinical staging of adenocarcinoma of the esophagogastric junction

Tumors of the esophagogastric junction are among the most frequent and cause lethal cancers. Patients often do not present until late in the disease when the tumor is sufficiently large to cause obstruction or invasion of the adjacent structures, and thus becomes symptomatic. Preoperative staging is critical to select those patients whose disease is still locally confined for curative surgery. Ideally, clinical staging should accurately predict tumor invasion, lymph node involvement, and distant metastases. Upper endoscopy establishes the tumor diagnosis by multiple biopsies and defines the tumor type (Siewert I-III), based on tumor localization in relation to the endoscopic cardia. Preoperative TNM staging has a strong impact on treatment strategy. Endoscopic Ultrasound (EUS) determines the T category, and to a lesser extent, the presence of lymph node metastases. Multislice Computed Tomography (CT) and 18Fluorode-ocx-glucose Positron Emission Computed Tomography (18FDG-PET-CT) provide further information, especially about systemic metastases. Diagnostic laparascopy is suggested in advanced (CT3/4) Siewert type II-III tumors to exclude peritoneal carcinomatosis. This chapter summarizes current staging modalities and their accuracy in clinical practice.