A Biomechanical Approach to Investigate the Applicability of the Lake-Thomas Theory in Porcine Aorta

Robot-assisted surgeries are procedures where a physician performs surgical maneuvers by operating a robot. One of the main limitations is the difficulty in transferring the surgeon’s multiple skills onto the robotic system. Such skills include the ability to estimate the maximum applicable force before damaging the tissue. To implement this skill onto a robotic system, a mathematical model for tissue damage must be developed. The objective of this study is to measure the fracture characteristic in porcine aorta, to then investigate whether an existing fracture model can be applied onto biological tissues. Due to the similarity in the mechanical response between biological tissues and polymeric materials, the model chosen for this study was the Lake-Thomas model. This is the first paper with the aim of validating this model with biological tissues. Two main findings are reported in this investigation. We found that porcine thoracic aorta tears in a specific way which is directly correlated to the tensile direction. The second finding is that an anisotropic linear relationship exists between the critical tearing energy and the elastic modulus, and the elastic modulus to the -0.5th power. These results are discussed based on the elastin and collagen fibers, as well as established mathematical equations describing polymer mechanic

An Aggressive Signet Ring Cell Carcinoma of the Prostate in a Japanese Man

Signet ring cell carcinoma (SRCC) of the prostate is rare, with approximately 100 case reports to date. Here we report a very aggressive case of SRCC of the prostate in a Japanese man. The patient received estramustine, docetaxel, and carboplatin combination chemotherapy, followed by TS-1 and CPT-11 combination therapy. Unfortunately, the disease progressed, and he died of general metastatic disease treated over 16 month with systemic chemotherapy

A Case of Squamous Cell Carcinoma of Conjunctiva as Initial Sign of Systemic Cancers

The purpose of this report is to present the findings in a case of squamous cell carcinoma (SCC) of the conjunctiva which was the initial sign of systemic cancers. A 94-year-old woman without known systemic diseases developed a mass in her right conjunctiva. She was referred to our hospital 5 months after the onset. She was diagnosed with conjunctival SCC by biopsy. Systemic CT before the surgery revealed multiple liver lesions, lung legions, and a large mass surrounding the appendix. The patient requested the surgery, and the main aim of the surgery was cosmesis. Histopathological examinations of the specimen led us to the final diagnosis as SCC. She did not receive any other therapy because of her age. As no other surgical procedures were undertaken, it is uncertain as to whether the conjunctival lesion was primary or secondary. Although, it is extremely rare that SCC of the conjunctiva is the initial sign of systemic cancers, careful systemic examinations to find other cancers should be made