Advancements and Challenges in Robot-Assisted Bone Processing in Neurosurgical Procedures.

OBJECTIVE: Practical applications of nerve decompression using neurosurgical robots remain unexplored. Our ongoing research and development initiatives, utilizing industrial robots, aim to establish a secure and efficient neurosurgical robotic system. The principal objective of this study was to automate bone grinding, which is a pivotal component of neurosurgical procedures. METHODS: To achieve this goal, we integrated an endoscope system into a manipulator and conducted precision bone machining using a neurosurgical drill, recording the grinding resistance values across 3 axes. Our study encompassed 2 core tasks: linear grinding, such as laminectomy, and cylindrical grinding, such as foraminotomy, with each task yielding unique measurement data. RESULTS: In linear grinding, we observed a proportional increase in grinding resistance values in the machining direction with acceleration. This observation suggests that 3-axis resistance measurements are a valuable tool for gauging and predicting deep cortical penetration. However, problems occurred in cylindrical grinding, and a significant error of 10% was detected. The analysis revealed that multiple factors, including the tool tip efficiency, machining speed, teaching methods, and deflection in the robot arm and jig joints, contributed to this error. CONCLUSION: We successfully measured the resistance exerted on the tool tip during bone machining with a robotic arm across 3 axes. The resistance ranged from 3 to 8 Nm, with the measurement conducted at a processing speed approximately twice that of manual surgery performed by a surgeon. During the simulation of foraminotomy under endoscopic grinding conditions, we encountered a -10% error margin.

Impact of skeletal muscle mass on postoperative complications in oral cancer surgery.

BACKGROUND: Sarcopenia is characterized by a progressive and generalized loss of skeletal muscle mass and strength. The aim of this retrospective study was to investigate the impact of skeletal muscle mass on adverse events in free-flap reconstruction for defects after oral cancer resection. RESULTS: Of 120 patients, recipient-site adverse events occurred in 56 patients (46.7%), and recipient-site surgical site infections occurred in 45 patients (37.5%). Skeletal muscle index was significantly associated with recipient-site adverse events in univariate analysis (P < 0.05). Lower body mass index and skeletal muscle index were significantly associated with recipient-site surgical site infection in univariate analysis (P < 0.05). In the multiple logistic regression model, a lower skeletal muscle index was a significant risk factor for recipient-site adverse events and surgical site infections (adverse events odds ratio; 3.17/P = 0.04; surgical site infection odds ratio; 3.76/P = 0.02). CONCLUSIONS: The SMI at level Th12 was an independent factor for postoperative AEs, especially SSI, in OSCC patients with free-flap reconstruction.

Alteration of Oral and Perioral Soft Tissue in Mice following Incisor Tooth Extraction.

Oral and perioral soft tissues cooperate with other oral and pharyngeal organs to facilitate mastication and swallowing. It is essential for these tissues to maintain their morphology for efficient function. Recently, it was reported that the morphology of oral and perioral soft tissue can be altered by aging or orthodontic treatment. However, it remains unclear whether tooth loss can alter these tissues' morphology. This study examined whether tooth loss could alter lip morphology. First, an analysis of human anatomy suggested that tooth loss altered lip morphology. Next, a murine model of tooth loss was established by extracting an incisor; micro-computed tomography revealed that a new bone replaced the extraction socket. Body weight was significantly lower in the tooth loss (UH) group than in the non-extraction control (NH) group. The upper lip showed a greater degree of morphological variation in the UH group. Proteomic analysis and immunohistochemical staining of the upper lip illustrated that S100A8/9 expression was higher in the UH group, suggesting that tooth loss induced lip inflammation. Finally, soft-diet feeding improved lip deformity associated with tooth loss, but not inflammation. Therefore, soft-diet feeding is essential for preventing lip morphological changes after tooth loss.

Temporal muscle thickness is associated with the severity of dysphagia in patients with acute stroke.

BACKGROUND: Post-stroke dysphagia is a common and expensive complication of acute stroke. The relationship between dysphagia and skeletal muscle loss (sarcopenia) has been recently highlighted. This study aimed to determine the relationship between temporal muscle thickness (TMT) measured by head magnetic resonance imaging (MRI) and dysphagia in patients with acute stroke. METHODS: Seventy participants (43 men and 27 women; mean age, 75.6 ± 12.7 years) were included in this study. TMT was measured by T2-magnetic resonance images within seven days of hospitalization. The severity of dysphagia was assessed using the Functional Oral Intake Scale (FOIS). Participants were classified into three categories according to the severity of dysphagia (severe: FOIS score, 1-3; mild: FOIS score, 4-6; normal: FOIS score, 7). Linear regression analysis was used to determine the independent explanators of dysphagia severity. RESULTS: Twenty participants (28.6%) had severe dysphagia, 31 participants (44.3%) had mild dysphagia, and 19 participants (27.1%) had normal swallowing function at discharge. The results of the linear regression analysis showed that TMT was a significant explanator of dysphagia severity following stroke, along with age and National Institute of Health Stroke Scale (NIHSS) score (P < 0.05, effect size: f2 = 0.72). CONCLUSIONS: TMT was an independent risk factor for dysphagia in patients with acute stroke. Skeletal muscle loss may be secondarily involved in dysphagia with acute stroke, and measurement of TMT with head MRI is a useful method to assess skeletal muscle loss.

Fluid Lubrication and Cooling Effects in Diamond Grinding of Human Iliac Bone.

Background and Objectives: Although there have been research on bone cutting, there have been few research on bone grinding. This study reports the measurement results of the experimental system that simulated partial laminectomy in microscopic spine surgery. The purpose of this study was to examine the fluid lubrication and cooling in bone grinding, histological characteristics of workpieces, and differences in grinding between manual and milling machines. Materials and Methods: Thiel-fixed human iliac bones were used as workpieces. A neurosurgical microdrill was used as a drill system. The workpieces were fixed to a 4-component piezo-electric dynamometer and fixtures, which was used to measure the triaxial power during bone grinding. Grinding tasks were performed by manual activity and a small milling machine with or without water. Results: In bone grinding with 4-mm diameter diamond burs and water, reduction in the number of sudden increases in grinding resistance and cooling effect of over 100 °C were confirmed. Conclusion: Manual grinding may enable the control of the grinding speed and cutting depth while giving top priority to uniform torque on the work piece applied by tools. Observing the drill tip using a triaxial dynamometer in the quantification of surgery may provide useful data for the development of safety mechanisms to prevent a sudden deviation of the drill tip.

Finite element method for nerve root decompression in minimally invasive endoscopic spinal surgery.

INTRODUCTION: Diagnosis is the key to improving spinal surgery outcomes. Improvements in the diagnosis of radiculopathy have created new indications for full-endoscopic spine surgery. We assessed the finite element method (FEM) to visualize and digitize lesions not detected by conventional diagnostic imaging. METHODS: We used FEM in two patients: a lumbar patient and a cervical patient. The lumbar patient was a 67-year-old woman with a history of rheumatoid arthritis; she also had osteoporosis and pulmonary fibrosis. She had left L3 radiculopathy due to an L3 vertebral fracture. The cervical patient was a 61-year-old woman with left C6 radiculopathy due to C5-C6 disc herniation. We performed full endoscopic foraminotomy per the patients's request. Based on preoperative and postoperative CT Digital Imaging and Communications in Medicine data of 0.5-mm slices, 3-D imaging data were reproduced, and kinetic simulation of FEM was performed. RESULTS: Postoperatively, both patients' radiculopathy disappeared, improving their activities of daily living and enabling them to walk and work. Also, the total contact area and maximum contact pressure of the nerve tissue decreased from 30% to 80% and from 33% to 67%, respectively. CONCLUSIONS: A new method for perioperative evaluation and simulation, FEM can be to visualize and digitize the conditions of the lesion causing radiculopathy. FEM that can overcome both time and economic constraints in routine clinical practice is needed.

Sjögren's syndrome and ranula development.

OBJECTIVES: We hypothesized that the extravasation of saliva from damaged ducts with lymphocytic infiltration in patients with Sjögren's syndrome causes ranulas. There are too many uncertainties to support this hypothesis. The aim of this study was to investigate whether there is an association between Sjögren's syndrome and ranulas. MATERIALS AND METHODS: We observed three cases of patients with ranulas who were also diagnosed with Sjögren's syndrome at the same facility. These cases led to the question of whether there are other such cases, and thus, an exhaustive literature search was conducted. RESULTS: Three cases in two case reports of mucocele of the floor of the mouth associated with adult Sjögren's syndrome were noted. Including our cases, until now, there have been six cases of ranula with adult Sjögren's syndrome. CONCLUSIONS: It could be useful to investigate whether patients presenting with a ranula are also affected by Sjögren's syndrome and, conversely, investigate patients with Sjögren's syndrome longitudinally to see whether they develop ranulas.

Schwannoma assumedly originating from the submandibular ganglion or glandular branches radiologically mimicking a submandibular gland tumor.

Schwannoma is a benign nerve sheath tumor composed of Schwann cells. Schwannomas originating from ganglia are rare, and schwannomas of the submandibular ganglion or glandular branches have not been reported to date. We present a case of a Japanese woman in her sixties with a submandibular schwannoma originating from the submandibular ganglion, mimicking a submandibular gland tumor on radiological findings. As the radiological findings were nonspecific, the key finding in the present case may be the characteristic location of the tumor suspended from the undersurface of the lingual nerve and situated above the deep portion of the submandibular gland.

Relationship between chewing ability and sarcopenia in Japanese community-dwelling older adults.

AIM: It has been reported that if nutrient intake is unbalanced, muscle mass, muscle strength and physical performance declines, and therefore it is important to maintain chewing ability to keep a balanced nutrient intake. However, the relationship between chewing ability and sarcopenia has not been previously reported. Therefore, the present study investigated the relationship between chewing ability and sarcopenia in addition to known sarcopenia-related factors. METHODS: We examined 761 participants (average age 73.0 ± 5.1 years), who lived in the Itabashi city of Tokyo. Our research was designed to examine the relationship between chewing ability and sarcopenia. We carried out regression analysis to analyze the relationship with sarcopenia-related factors with consideration of the age of the participants. RESULTS: The 761 participants were divided into two groups in terms of the stage of sarcopenia according to whether there was a deterioration of muscle strength or physical performance. Furthermore, we carried out logistic regression analyses on the value as a dependent variable, including known sarcopenia-related factors. There were significant correlations of sarcopenia with age (odds ratio 2.37, 95% confidence interval 1.52-3.70), body mass index (odds ratio 0.75, 95% confidence interval 0.69-0.81) and chewing ability (odds ratio 2.18, 95% confidence interval 1.21-3.93). CONCLUSIONS: The present study shows that chewing ability is related to sarcopenia, which is equal to the relationship with the known factor of age by odds ratio.

Risk factors for postoperative dysphagia in oral cancer.

With the founding of its Oral Cancer Center at the Ichikawa General Hospital, Tokyo Dental College established a support system for patients and family members that not only provides surgery and other conventional cancer-oriented treatments, but also palliative care, nutritional support, rehabilitation, and discharge support. With this in mind, the present study sought to examine the nature of support for oral cancer patients with postoperative eating and swallowing disorders by investigating these disorders and identifying their risk factors. The study population comprised 75 surviving oral cancer patients (46 men and 29 women) discharged from the Tokyo Dental College Oral Cancer Center following treatment over a 2-year period from April 2009 to March 2011. Risk factors affecting eating and swallowing function were identified by statistical analysis. Mean age of the patients was 67.3±13.7 years. Fifteen patients had stage I cancer, while 25 had stage II, 13 had stage III, and 22 had stage IV. The feeding route at the time of discharge was oral feeding in 74 patients and a combination of oral and gastrostomy tube feeding in 1 patient. The Tokyo Dental College Ichikawa General Hospital has standardized the expert evaluation and rehabilitation of oral cancer patients with eating and swallowing disorders by establishing a multidisciplinary support system from the preoperative stage onwards. In this context, the results of our analysis of factors influencing the ability of oral cancer patients to orally ingest food after treatment suggest that preoperative cancer stage classification, neck dissection, and tracheotomy are all influential factors. Patients affected by these factors require further multidisciplinary treatment, which in turn necessitates more extensive coordination with other medical professionals and community health care providers.