Odontoidectomy is very effective for the decompression of the ventral craniovertebral junction (CVJ). Various approaches are available for the direct ventral decompression of the CVJ. Because there are many disadvantages of open transoral approach, endoscopic odontoidectomy was developed. There are 3 approaches in endoscopic odontoidectomy. We report transcervical retropharyngeal endoscopic approach for the ventral CVJ in this paper. Three patients with different pathologies received operations using this approach. The decompression was enough and surgical invasion was less in all patients. Each endoscopic approach has some advantages and different working regions due to their approach trajectories, but transcervical retropharyngeal approach is very familiar for our neurospinal surgeons and has a relatively large working area. This approach might have the chance to take the place of open transoral approach for endoscopic spinal surgeons.

Objective: This study was aimed to report the clinical characteristics of intramedullary schwannomas and discuss imaging findings and treatment strategies.Methods: The inclusion criterion was consecutive patients with intramedullary schwannomas who were surgically treated at 8 centers between 2009 and 2020. Clinical characteristics included age, sex, clinical presentation, disease duration, and follow-up period. The modified McCormick scale was used to compare the preoperative and postoperative conditions. Pre- and postoperative magnetic resonance images (MRI) of each case were analyzed.Results: The mean age of the total 11 patients at the operation was 50.2 years. The mean duration of the symptoms was 23 months, with limb paresthesia being the most common clinical presentation. The cervical spine was the most common localization level of the tumor in 6 cases. The mean follow-up duration was 49.4 months. Gross total resection (GTR) and subtotal resection (STR) was achieved in 9 and 2 cases, respectively. According to the modified McCormick scale at 6 months postoperatively, 7 cases (63.6%) had improved and 4 cases (36.3%) had unchanged grades. Typical MRI findings of the intramedullary schwannoma included ring-like enhancement, syringomyelia, cystic formation, intramedullary edema, and hemosiderin deposition. Gadolinium enhancement was homogenous in 8 cases (72.7%). The tumor margins were well demarcated in all cases.Conclusion: Intramedullary schwannoma should be considered when sharp margins and well-enhanced tumors are present at the cervical spine level and the initial symptoms are relatively mild, such as dysesthesia. When GTR cannot be achieved, STR for tumor decompression is recommended.

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.

Background: It is important to differentiate intramedullary neoplastic lesions from nonneoplastic diseases such as multiple sclerosis (MS) and other demyelinating or inflammatory diseases. Case Description: A 26-year-old Japanese male presented with a history of intracranial germinomas and obstructive hydrocephalus, treated with endoscopic surgery, and adjuvant chemotherapy and radiation therapy. Three years later, he developed paresthesias involving the right hand and both lower extremities. The cervical MR scan demonstrated a heterogeneously enhancing intramedullary C1-C2 lesion with surrounding edema. On cytological examination of the cerebrospinal fluid (CSF), there were no neoplastic cells. However, the fluid was positive for oligoclonal immunoglobulin G (IgG) bands. The patient received steroid pulse therapy to address the potential MS diagnosis. The follow-up MR showed reduced edema, but no change in the size of the intramedullary lesion. Therefore, the patient underwent a cervical laminectomy for tumor resection. The pathology was consistent with the same cranial germinoma treated 3 years previously. He subsequently received whole spinal radiation and three courses of chemotherapy. Conclusion: Some spinal cord tumors may produce oligoclonal IgG bands in CSF. In this case, an intramedullary C1-C2 spinal cord germinoma was originally misdiagnosed as MS due to the presence of oligoclonal IgG bands in CSF. Differentiating this tumor from MS and initiating appropriate treatment were critical into the care of this patient.