Published papers

Background: Microsurgery requires high skills for suturing using fragile threads, often within narrow surgical fields. Precise tension is required for good healing and to avoid the risk of thread breakage. Methods: To meet the demands, we developed a novel assist robot utilizing high-precision sensorless haptic technology. The robot adopts a cable-driven mechanism to maintain a distance from the surgical area and enhances compatibility with surgical equipment such as microscopes. The robot performance was verified through in vitro and in vivo experiments using a rat model. Results: The realization of precise tension control was confirmed in both experiments. In particular, in the in vivo experiments, the developed robot succeeded to produce a knot with an accurate tension of 0.66% error. Conclusions: The developed robot can realize to control traction force precisely. This technology might open up the window for a full assist robot for microsurgery with haptic feeling.

We report the case of a 66-year-old man who had a left forehead mass for 5 years.　Positron emission tomography-computed tomography（PET-CT）was performed in 2013 because he had tongue cancer，and it revealed cutaneous accumulation at the left forehead; however，the standardized uptake value（SUV）was low and passage was observed. On PET-CT performed in 2015，an increase in cutaneous accumulation was noted，and therefore，skin biopsy was performed. Pathological findings indicated accumulation in luminal structures of various sizes and a cribriform structure from the dermis to the galea aponeurotica. The luminal structures included basophilic cells，which contained basophilic material. Additionally，neuronal invasion was noted. Therefore，he was diagnosed with primary cutaneous adenoid cystic carcinoma，and surgery was performed. No recurrence has been noted for 5 months following surgery. Adenoid cystic carcinoma often shows neuronal invasion and regional relapse. Therefore，extended resection and a long-term follow-up are needed. Even if the SUV is low，it is important to perform dermatological examinations.

Abstract:Lingual bone defects are usually asymptomatic local concavities of the lingual cortical bone of the mandible, frequently caused by soft-tissue inclusion. In most cases, the soft tissue is the submandibular gland. Only 7 cases of developing lingual bone defects were previously reported in Japan, but none of these cases involved the sublingual gland. We report a rare case of a developing lingual bone defect associated with the sublingual gland, which we followed up for 21 years. The patient was a 58-year-old man who had a developing lingual bone defect in the anterior right side of the mandible. A panoramic X-ray film showed an oval radiolucent area in the apical region of the lower right canine and first premolar tooth. Moreover, electric pulp testing confirmed that all teeth in the lower-right quadrant were vital. A panoramic X-ray film obtained at a nearby dental clinic demonstrated a radiolucent area 15 years before presentation to our department, and the area showed evidence of gradual expansion. Computed tomography revealed a local concavity in the lingual cortical bone of the right side of the mandible. The concavity measured 13 × 9 mm. The signal intensity of the inner tissue of the bone defect was nearly equivalent to that of the sublingual gland on T1-, T2-weighted magnetic resonance imaging. The suspected clinical diagnosis was a lingual bone defect. We performed an incisional biopsy to rule out a neoplastic lesion, and the histopathological diagnosis was normal sublingual gland tissue. On the basis of these results, the final diagnosis was a developing lingual bone defect associated with the sublingual gland. Two years have elapsed, but there is no swelling or induration in the right sublingual gland. The radiolucent area on the panoramic X-ray film showed decreased radiolucency and increased bone volume. Moreover, computed tomography revealed that the concavity of the bone had shrunk.

Abstract:Non-islet-cell tumor hypoglycemia (NICTH), a condition characterized by recurrent episodes of hypoglycemia, rarely occurs in association with oral cancer. Here, we report a case of carcinoma of the maxillary gingiva with NICTH caused by paraneoplastic production of insulin-like growth factor II (IGF-II). A 72-year-old man with a painful swelling in the left maxillary region was referred to our hospital. A mass with induration was observed in the buccal and palatal regions from the first premolar to the second molar. The clinical diagnosis was carcinoma of the maxillary gingiva, and a biopsy revealed squamous cell carcinoma. The patient received concurrent radiation and chemotherapy with cisplatin. Three weeks after the completion of treatment, three episodes of hypoglycemia developed despite normal intake of meals. On the basis of the results of endocrinological examinations, typical diseases causing hypoglycemia, such as insulinoma and adrenal insufficiency, were ruled out. Furthermore, decreased IGF-I levels were found, which indirectly revealed an increase in IGF-II levels. On the basis of these findings, we diagnosed this case as carcinoma of the maxillary gingiva with NICTH. Continuous intravenous glucose infusion was needed for 3 months from the diagnosis of NICTH until death. NICTH should be borne in mind as one of the complications that can occur during treatment of oral cancer.

Abstract Oral lichen planus is a chronic inflammatory mucocutaneous disease. Topical use of steroids and other immuno-modulating therapies have been tried for this intractable condition. Nowadays, tacrolimus ointment is used more commonly as a choice for treatment. However, a number of discussions have taken place after tacrolimus was reported to be carcinogenic. This report describes a patient who applied tacrolimus ointment to the lower lip after being diagnosed with oral lichen planus in 2008, and whose lesion developed squamous cell carcinoma in 2010. Since the relationship between tacrolimus and cancer development has been reported in only a few cases, including this case report, the clinician must be careful selecting tacrolimus as a second-line treatment for oral lichen planus.