MRI-guided laparoscopic and robotic surgery for malignancies

Robotic Surgery in Gastrointestinal Surgery

Robotic surgery is expanding in the minimally invasive treatment of gastrointestinal cancer. In the field of gastrointestinal cancer, robotic surgery is performed using a robot-assisted surgery system. In this system, the robot does not operate automatically but is controlled by the surgeon. The surgery assistant robot currently used in clinical practice worldwide is the leader-follower type, including the da Vinci® Surgical System (Intuitive Surgical). This review describes the current state of robotic surgery in the treatment of gastrointestinal cancer and discusses the future development of robotic systems in gastrointestinal surgery.

Future Perspectives of Surgery for Esophageal Cancer

Esophageal cancer is one of the leading causes of cancer-related death worldwide. Surgery plays an important role in the treatment strategies for esophageal cancer. Recent advances in surgical techniques and perioperative management have dramatically improved the mortality rate; however, esophagectomy remains a highly invasive procedure that can lead to severe postoperative complications. Future advances in thoracoscopic surgery with the development of surgical endoscopy systems such as three-dimensional (3D) imaging systems with a 4K ultra high-definition camera or two-dimensional (2D) imaging systems with an 8K camera, which is expected to provide 3D-like visual sensation, will enable us to further understand the microscopic anatomy of the thoracic cavity and mediastinum, and to perform delicate surgical procedures that enable minimally invasive esophagectomy with mediastinal lymphadenectomy. A robot-assisted thoracoscopic esophagectomy is attractive for surgeons and may be beneficial to esophageal cancer patients. Preoperative simulation and intraoperative real-time navigation are expected to further help surgeons safely perform esophagectomy with lymphadenectomy. Reduction of the lymphadenectomy field and setting of lymphadenectomy areas with highest priority may be feasible when sentinel node (SN) navigation is appropriately performed in cN0 early-stage esophageal cancer. These technical advances are expected to decrease the morbidity and mortality rate of surgery for esophageal cancer and hopefully improve oncological outcomes.

MR-Safe Pneumatic Rotation Stepping Actuator

Magnetic Resonance Imaging (MRI) is widely used not only for diagnosis but also for surgical navigation, etc. Surgeons and surgery-support systems can conduct surgeries less invasively because they derive accurate positional relationships between surgical instruments and anatomical regions of interest from preoperative or intraoperative MRI images. Many surgical robots intended for use within MRI gantries have been developed. Some of them use pneumatic actuators that are difficult to control accurately or that have many components, however, causing high fabrication cost, low durability and low sterilizability. To solve these problems, we have developed a φ30-mm pneumatic rotation stepping actuator. The actuator consists of three Direct Acting gears (D.A. gears) and a Rotation gear (R gear). When all of the D.A. gears are pushed sequentially up by compressed air, the R gear rotates because it engages all of them. In a fundamental performance experiment, the maximum angular error was 2.1° and maximum torque was approximately 150 mNm using 0.6 MPaG. Additionally, in an MR safety evaluation, the actuator was not found to cause any distortion or artifacts in MRI images. The actuator can therefore be applied to MR-safe positioning or puncturing robots.

Short-term outcomes of CyberKnife therapy for advanced high-risk tumors: A report of 160 cases

The objective of the present study was to evaluate short-term outcomes of CyberKnife therapy in patients with advanced high-risk tumors. A total of 201 target areas from 341 advanced high-risk tumor lesions in 160 patients were treated with CyberKnife. A prescribed dose of 18-60 Gy to the gross tumor volume was delivered in 1-6 fractions to complete the entire treatment in 1 week. Radiographic studies and clinical examinations were performed at 1- to 3-month follow-up intervals, and the results were compared to outcomes of 160 similar advanced high-risk tumor patients who were treated by conformal radiotherapy (CRT). After CyberKnife therapy, the short-term improvement in the quality of life was significant according to radiographic study, radioimmunoassay and ZPS scores of these patients. The total rates of objective efficacy and alleviation of ascities were as high as 66.88 and 67.90%. The short-term outcomes in our series of patients with advanced high-risk tumors treated with CyberKnife appeared to be better compared to conventional CRT. CyberKnife may be an option for patients with incurable advanced high-risk tumors, although further studies of the long-term outcomes are required to confirm the validity.

Assessment of the evolution of cancer treatment therapies

Cancer therapy has been characterized throughout history by ups and downs, not only due to the ineffectiveness of treatments and side effects, but also by hope and the reality of complete remission and cure in many cases. Within the therapeutic arsenal, alongside surgery in the case of solid tumors, are the antitumor drugs and radiation that have been the treatment of choice in some instances. In recent years, immunotherapy has become an important therapeutic alternative, and is now the first choice in many cases. Nanotechnology has recently arrived on the scene, offering nanostructures as new therapeutic alternatives for controlled drug delivery, for combining imaging and treatment, applying hyperthermia, and providing directed target therapy, among others. These therapies can be applied either alone or in combination with other components (antibodies, peptides, folic acid, etc.). In addition, gene therapy is also offering promising new methods for treatment. Here, we present a review of the evolution of cancer treatments, starting with chemotherapy, surgery, radiation and immunotherapy, and moving on to the most promising cutting-edge therapies (gene therapy and nanomedicine). We offer an historical point of view that covers the arrival of these therapies to clinical practice and the market, and the promises and challenges they present.

Hyperelastic Model of Anisotropic Fiber Reinforcements within Intestinal Walls for Applications in Medical Robotics

The development of an anatomically realistic model of intestinal tissue is essential for the progress of several clinical applications of medical robotics. A hyperelastic theory of the layered structure of the intestine is proposed in this paper to reproduce its purely elastic passive response from the structural organization of its main constituents. The hyperelastic strain energy function is decoupled into an isotropic term, describing the ground biological matrix, and an anisotropic term, describing the single contributions of the directional fiber-reinforcements. The response of the muscular coat layer has been modeled as a stiffening effect due to two longitudinal and circular muscular reinforcements. The contribution of the submucosa has been described from a uniform distribution of fibrillar collagen in a cross-ply arrangement. An experimental procedure has been proposed in order to characterize the passive response of porcine intestinal samples from planar uniaxial traction and shear tests. The experimental data have been non-linearly fitted in the least square sense with the results of the theoretical predictions. The mechanical parameters have been fitted with high accuracy (Rmin =0.9329, RMSEmax =0.01167), demonstrating the ability of the model to reproduce the mechanical coupling due to the presence of multiple directional reinforcements. The fundamental mechanical role of collagen morphology in the passive biomechanical behavior of intestinal wall is demonstrated. These results may drive a better understanding of the key factors in growth and remodeling of healthy and diseased tissue, together with numerous applications in robotic endoscopy, minimally invasive surgery, and biomedical research.