Cervical laminoplasty is a well-established surgical approach for managing various cervical spine pathologies, including cervical spondylotic myelopathy, spinal canal stenosis, and ossification of the posterior longitudinal ligament. Among the available laminoplasty techniques, the use of Hydroxyapatite spacers secured with screws is common for maintaining the expanded interlaminar space. However, one potential complication is screw back-out, which, although recognized, has rarely been documented in the literature. We present a rare case of delayed screw migration culminating in skin perforation in a 76-year-old woman who underwent cervical laminoplasty for cervical spondylotic myelopathy. During the index procedure, Hydroxyapatite spacers were placed and secured with screws into the lamina. Seven years postoperatively, gradual subcutaneous migration of the screw from the lamina of the fourth cervical vertebra was observed, ultimately resulting in complete skin penetration 9 years after the initial surgery. The patient underwent surgical removal of the protruding screw along with surrounding granulation tissue. The surgical site was thoroughly irrigated with copious saline, and the wound was closed primarily with sutures. Postoperative recovery was uneventful. Stitches were removed on day 11 after confirming complete wound healing. This case underscores an exceptionally rare but clinically significant late complication of cervical laminoplasty with Hydroxyapatite spacers -complete screw extrusion through the skin. To our knowledge, this is the first documented case of its kind. The prolonged asymptomatic nature of screw migration in this patient highlights the importance of long-term surveillance following laminoplasty, even in the absence of clinical symptoms, to detect hardware-related complications at an early stage.

Solitary plasmacytoma is a hematologic malignancy in which about 50% of cases progress to multiple myeloma within 10 years. Local radiation therapy is effective for solitary plasmacytoma treatment, but there are cases of spinal cord paralysis due to osteolytic pathological fractures in the spine. Here, we report a 63-year-old male with spinal cord injury caused by pathologic fracture progression after radiotherapy. A 63-year-old male presented with neck pain and left hemiplegia. Imaging studies revealed a pathological fracture of the C5 vertebral body, and biopsy confirmed the diagnosis of solitary plasmacytoma. Radiation therapy temporarily improved symptoms, but progressive quadriplegia developed 2 months later. Cervical spinal cord compression due to an additional vertebral bone fracture was confirmed. Aggressive lesionectomy and fixation using simultaneous anterior and posterior combined approaches were performed. Postoperatively, paralysis completely recovered. No local recurrence or transition to multiple myeloma was observed even after 7 years of follow-up at age 70. Surgical treatment may be effective for spinal cord injury associated with pathologic fracture progression after radiotherapy for solitary plasmacytoma.

Flow diverters have revolutionized the treatment of large and giant cerebral aneurysms. However, aneurysms with branch vessels originating from the aneurysm sac remain challenging for flow diverter monotherapy. We present five cases demonstrating favorable outcomes following combined treatment with overlapping flow diverter with coiling. The study cohort included five female patients with a mean age of 72.8 years. The mean aneurysm diameter was 8.1 mm. Triple antithrombotic therapy (dual antiplatelet therapy plus short-term anticoagulation) was administered to prevent ischemic complications due to posterior communicating artery occlusion in the perioperative period. Complete or near-complete occlusion (O'Kelly-Marotta grade C or D) was achieved in all cases. Follow-up angiography (mean follow-up time: 17.2 months) revealed preserved patency of the posterior communicating artery in four of five cases. In one case, the posterior communicating artery arising from the aneurysm was occluded at its origin but was supplied retrograde from the posterior circulation. Follow-up digital subtraction angiography of most cases showed caliber changes, with the posterior communicating artery diameter reducing and the P1 segment of the posterior cerebral artery increasing. No ischemic or hemorrhagic complications occurred perioperatively or during follow-up. Overlapping flow diverter with coiling combined with low-dose and short-term triple antithrombotic therapy might be a safe and effective treatment for fetal-type posterior communicating artery aneurysms, offering a viable alternative for complex aneurysms. Further studies with long-term follow-up data from a larger patient cohort are required to validate the efficacy and safety demonstrated in this case series.

To investigate whether oral contraceptives induce acute ischemic stroke in patients with moyamoya disease. We retrospectively reviewed female patients with moyamoya disease who were taking oral contraceptives during their reproductive years (12-49 years of age) at the time of diagnosis or during follow-up. The patients' detailed clinical history, including the time course of oral contraceptive usage and acute ischemic stroke occurrence, was evaluated. For patients with radiological evidence of acute ischemic stroke, the imaging pattern of stroke was assessed to investigate the underlying mechanisms. Among 589 female patients, 12 patients took oral contraceptives at some point during the period from 2012 to 2023; 5 patients were taking oral contraceptives at the time of diagnosis, and 4 of them were diagnosed with moyamoya disease after acute ischemic stroke. Among the 7 patients who started oral contraceptives during follow-up, 2 patients developed acute ischemic stroke several months after starting oral contraceptives. Notably, none of the hemispheres that developed acute ischemic stroke previously underwent revascularization, and none of the 5 hemispheres with prior revascularization developed acute ischemic stroke. The imaging pattern of acute ischemic stroke in 7 patients suggested the contribution of a thromboembolic mechanism. Oral contraceptives may increase the risk of acute ischemic stroke via thromboembolic mechanisms in patients with moyamoya disease, but its risk might be manageable in hemispheres with prior revascularization and stable disease conditions for years. Active education of patients regarding the possible risk of oral contraceptives and close communication with gynecologists seem necessary to provide the best treatment strategies for female patients with moyamoya disease who require contraception or treatment of menstrual disorders.

Cardioembolic stroke caused by tumor emboli is a rare form of cancer-associated stroke. We report a case of a patient with cardiac metastasis of extraskeletal chondrosarcoma who developed left internal carotid artery occlusion due to embolic stroke. Extraskeletal chondrosarcoma is an extremely rare subtype of soft tissue sarcoma characterized by a tendency for local recurrence and metastasis. Endovascular thrombectomy was performed using a combined technique, achieving complete revascularization. Histopathological analysis of the retrieved cell mass confirmed that the embolic source was the preexisting extraskeletal chondrosarcoma.

Diffuse midline glioma, H3K27-altered, is a rare and aggressive central nervous system tumor that typically affects children, whereas adult cases are uncommon and less well characterized. We report a 43-year-old woman who experienced progressive lightheadedness for 10 months and was diagnosed with orthostatic hypotension on the basis of a positive tilt-table test result. Despite treatment with midodrine, her symptoms worsened, and dysarthria, dysphagia, sensory disturbance, and gait instability later developed. Magnetic resonance imaging confirmed an intra-axial mass in the dorsal medulla oblongata. Partial resection was performed, and histopathological examination with immunohistochemistry confirmed the diagnosis of H3K27-altered diffuse midline glioma. The patient subsequently received adjuvant chemoradiotherapy. Although her motor function improved postoperatively, severe orthostatic hypotension persisted, leading to recurrent syncopal episodes that significantly hindered rehabilitation. The solitary nucleus in the dorsal medulla plays a central role in the baroreflex by relaying sympathetic and parasympathetic signals within the central autonomic network. Disruption of this network by medullary tumors can impair blood pressure regulation, causing orthostatic hypotension. Although orthostatic hypotension has been reported in association with various medullary tumors, gliomas are rarely implicated. To our knowledge, this is the first reported case of medullary diffuse midline glioma presenting with orthostatic hypotension under the current World Health Organization molecular classification. This case highlights the importance of considering brain magnetic resonance imaging in patients with newly developed or severe orthostatic hypotension, particularly when accompanied by neurological symptoms, to enable timely diagnosis and management.

Myxoid glioneuronal tumor is a newly included entity in the 2021 World Health Organization classification of central nervous system tumors, based on both pathological and molecular evidence, characterized by platelet-derived growth factor receptor alpha mutations. A 23-year-old female presented with intermittent visual field abnormalities and dizziness. Magnetic resonance imaging revealed a 2-cm mass occupying both foramens of Monro, leading to non-communicating hydrocephalus. Endoscopic surgery via the transcortical approach achieved gross total resection of the tumor. Postoperatively, she developed cognitive dysfunction involving recent memory disturbance and progressive ventricular dilation, necessitating a ventriculoperitoneal shunt, which led to significant cognitive recovery. Histopathological analysis confirmed myxoid glioneuronal tumor with a platelet-derived growth factor receptor alpha p.K385L mutation. A review of 23 cases, including ours, indicates that surgical resection is the preferred treatment and is generally associated with a favorable prognosis. However, recurrence and meningeal dissemination have been reported in some cases, emphasizing the need for long-term follow-up. Myxoid glioneuronal tumor is frequently located close to critical structures like the fornix, so careful surgical planning is essential to balance maximal resection with functional preservation. Endoscopic techniques offer advantages for deep-seated lesions by minimizing cortical damage while allowing adequate tumor resection. Further studies are needed to establish the optimal treatment strategies and clarify the long-term prognosis of myxoid glioneuronal tumor.

Spinal arachnoid cysts are relatively uncommon lesions, broadly classified as either congenital or acquired. Acquired cysts may develop following trauma, hemorrhage, or post-infectious inflammation. Depending on their location, these cysts can cause a range of symptoms, including quadriplegia, pain, sensory disturbances, and gait impairment. Surgical resection may be indicated in cases with significant neurological symptoms. We report the case of a 77-year-old woman who presented with persistent bilateral leg numbness and pain. Magnetic resonance imaging revealed a suspected intradural spinal arachnoid cyst or arachnoid web at the Th7-8 level, and surgery was planned to relieve the symptoms.

A laminectomy was performed, revealing a cystic, membrane-like structure in the subdural space. By injecting a crystal violet staining solution into the cyst, we enhanced the visibility of the boundary between the normal arachnoid membrane and the cyst, allowing for complete resection. Postoperatively, the patient experienced improvement in leg pain and numbness. This case demonstrates that crystal violet staining can facilitate clear boundary recognition during arachnoid cyst resection, enabling more precise cyst removal.

We report a case of successful diaphragm pacing in a patient with severe traumatic spinal cord injury resulting in complete ventilator dependence. A 29-year-old man sustained a traumatic cervical spinal injury at the C3 level. On admission, he exhibited tetraplegia, complete sensory loss below the C6 dermatome, and acute respiratory failure. Emergency spinal decompression surgery was performed; however, neurological deficits showed no improvement. Despite intensive respiratory rehabilitation, the patient remained fully dependent on mechanical ventilation. Diaphragm pacing implantation was planned approximately 17 weeks post-injury. Intraoperative electrical stimulation revealed no responsiveness in the left diaphragm, whereas the right diaphragm demonstrated sufficient contractility. After estimating that adequate tidal volumes could be achieved through unilateral right diaphragmatic stimulation, bilateral diaphragmatic electrodes were laparoscopically implanted. Diaphragm pacing was initiated on postoperative day one, gradually increasing pacing duration daily while maintaining exertion levels below the Borg scale 4. By day 46 post-implantation, the patient achieved complete independence from mechanical ventilation despite persistent left diaphragmatic paralysis. Enhanced right diaphragmatic function was confirmed by increased diaphragmatic thickness and thickening fraction. Additionally, improved sputum clearance allowed withdrawal from cough-assist therapy and subsequent closure of tracheostomy. At 1-year follow-up, the patient maintained independent respiration without device-related complications. This case highlights the potential efficacy of early diaphragm pacing implantation in patients with high cervical spinal cord injury, demonstrating favorable respiratory outcomes even in the presence of unilateral diaphragmatic dysfunction.

Marfan syndrome presents unique challenges for mechanical thrombectomy in acute ischemic stroke due to vascular fragility and complex aortic anatomy, often from prior surgeries. We describe the case of a man in his 50s with Marfan syndrome, total aortic arch replacement, mechanical valve replacement, and extensive chronic dissections, who presented with acute ischemic stroke due to right internal carotid artery occlusion. Conventional transfemoral access failed due to anomalous prosthetic brachiocephalic artery graft anatomy. Consequently, mechanical thrombectomy was performed via direct surgical exposure and puncture of the right common carotid artery. Despite initial avoidance of a stent retriever due to Marfan syndrome-related vessel fragility, an stent retriever was ultimately used in a combined technique with aspiration in the third pass, achieving partial recanalization (thrombolysis in cerebral infarction 2a) and retrieval of a fibrin-rich thrombus. This case highlights direct carotid access as a feasible alternative in Marfan syndrome patients with prohibitive conventional access and suggests stent retrievers can be used cautiously.

Abusive head trauma in infants and young children can have a significant impact on neurological outcomes and, in severe cases, may be life-threatening. We report 3 cases of abusive head trauma that presented with acute subdural hematomas on computed tomography scans, accompanied by extensive low-density areas and parenchymal brain swelling. All patients exhibited impaired consciousness due to brain injury and underwent craniotomy for hematoma evacuation as well as extensive decompressive craniectomy. Despite the severity of the initial presentation, hemiparesis was mild and gradually improved over several months. Postoperative magnetic resonance imaging revealed widespread parenchymal injury but preservation of the corticospinal tract, including the precentral gyrus. In the acute phase, diffusion-weighted imaging showed no irreversible infarction in the motor cortex, and arterial spin labeling demonstrated increased perfusion in peri-motor regions of the affected hemisphere. These findings suggest that preserved corticospinal pathways and compensatory hyperperfusion may correlate with favorable motor recovery even in the presence of extensive parenchymal damage. These cases highlight the radiological features and short-term neurological outcomes of abusive head trauma, demonstrating preserved motor function despite extensive parenchymal damage.

Choroid plexus cysts are typically benign lesions found within the ventricular system during prenatal imaging and are usually asymptomatic. Intraparenchymal choroid plexus cysts, especially in adults, are exceptionally rare, with very few reported cases. This case report aims to present a rare instance of a symptomatic, intraparenchymal choroid plexus cyst in an adult patient and to discuss the diagnostic and surgical considerations involved. We present the case of a 50-year-old man with complaints of lower extremity weakness and imbalance who was found to have a bilobulated cyst in the frontal cortex causing significant mass effect and midline shift. The patient underwent cyst fenestration through endoscope-assisted open craniotomy, with marked postoperative reduction in cyst size and resolution of neurological symptoms. Histopathology confirmed the diagnosis of a choroid plexus cyst. This case highlights the importance of considering rare pathologies such as choroid plexus cysts in the differential diagnosis of cystic brain lesions with mass effect in adults.

Aneurysms of the meningohypophyseal trunk are rare and usually asymptomatic, but because of the close anatomical relationship between the meningohypophyseal trunk and cranial nerves within the cavernous sinus, they can cause neurological deficits. We describe an 80-year-old woman who presented with acute horizontal diplopia exacerbated on rightward gaze. Neurological examination revealed isolated right abducens nerve palsy. Magnetic resonance angiography demonstrated an aneurysm arising from the right meningohypophyseal trunk in close proximity to the abducens nerve. Endovascular coil embolization was performed under dual antiplatelet therapy, and the aneurysm was successfully occluded while preserving meningohypophyseal trunk patency. The procedure was uneventful, although postoperative diffusion-weighted imaging revealed multiple small cerebral infarctions suggestive of distal embolism. The patient remained neurologically stable, and her diplopia gradually improved. At the 6-month follow-up, she exhibited complete recovery of abducens nerve function. This case highlights the anatomical vulnerability of the abducens nerve to compression by meningohypophyseal trunk aneurysms and underscores the importance of considering vascular lesions in the differential diagnosis of isolated cranial nerve palsies. Despite radiographic evidence of silent embolic infarction, endovascular coil embolization resulted in full clinical recovery, supporting its role as a safe and effective therapeutic option in appropriately selected symptomatic meningohypophyseal trunk aneurysms.

Although rare, thrombosed vertebral artery aneurysms can lead to severe symptoms and are challenging to treat due to their proximity to vital structures. The location of a thrombosed aneurysm on the anterior aspect of the brainstem poses a significant challenge to conventional microscopic approaches. We herein report a 78-year-old man with a thrombosed right vertebral artery aneurysm who developed progressive quadriparesis, dysphagia, and respiratory failure despite prior interventions, including flow diverter stent placement, parent artery occlusion, and microscopic thrombectomy. Given worsening medullary compression and poor clinical status, intra-aneurysmal thrombectomy was performed using an exo-endoscopic 2-step approach. The procedure involved reopening the previous suboccipital craniotomy, partial condylectomy, and C1 hemilaminectomy. Exoscopic thrombus de-bulking was followed by endoscopic evacuation of the residual thrombus compressing the ventral brainstem. Postoperatively, no complication was observed, and the patient demonstrated gradual neurological improvement, including recovery of spontaneous respiration and the ability to wean from mechanical ventilation within 3 weeks. Follow-up imaging confirmed resolution of medullary compression without thrombus recurrence. The exo-endoscopic 2-step approach is a viable option for surgical decompression of thrombosed vertebral artery aneurysms that cause brainstem compression. This enhances surgical access and visualization, particularly in the ventral brainstem, while potentially minimizing brainstem manipulation. Further investigation is warranted to better define the indications, efficacy, and safety of the management of complex thrombosed aneurysms.

This report presents 2 cases demonstrating how a foraminal block served as both a diagnostic tool and an effective treatment for small far-lateral lumbar disc herniation at L5-S1 in elite athletes. The patients were a male swimmer in his early 20s and a female figure skater in her late teens, both of whom developed activity-related low back pain, with symptoms acutely exacerbated by the high flexion and extension loads inherent to their sports, which compromised their ability to compete at the highest level. A fluoroscopy-guided foraminal block was performed in each case; the key technical component was careful paraneural needle placement, stopping just short of the nerve root to minimize the risk of iatrogenic injury while targeting the inflammatory environment throughout the foramen. The diagnosis was confirmed in both athletes by reproducing their specific pain during injection. This non-operative intervention provided pain relief that was sufficient for successful participation in a major international competition in one case and continuation of a critical qualifying season for a premier global event in the other. This approach represents a critical diagnostic and therapeutic strategy that can avoid the need for surgery and preserve an elite athlete's immediate career goals.

This report discusses the case of a 70-year-old male orthopedic surgeon with multilevel lumbar foraminal stenosis and degenerative scoliosis (Cobb angle 21°) who presented with right leg radiculopathy and foot drop. To accommodate his inability to take extended leave and his desire to avoid fusion, we performed a staged transforaminal full-endoscopic lumbar foraminotomy, consisting of one procedure per level, under local anesthesia. The procedures targeted the L5/S1, L4/5, and L3/4 levels sequentially at 1-month intervals. The patient's foot drop resolved immediately after the first surgery. At the 3-month follow-up after the final procedure, his motor deficits showed marked improvement, and his Oswestry Disability Index score decreased from 12% to 8%. He returned to his clinical duties the day after each discharge and was able to continue managing his private clinic without interruption. He resumed playing golf 2 months after the final surgery. A staged, non-fusion transforaminal full-endoscopic lumbar foraminotomy approach under local anesthesia was a safe and effective strategy for multilevel foraminal stenosis, even in the presence of deformity, providing excellent functional recovery with minimal disruption to the patient's professional life.

Dural laceration is a critical complication in full endoscopic spinal surgery. We need to recognize precise surgical anatomy to avoid it. Recently identified dorsal meningovertebral ligaments, connecting the dorsal spinal dura mater to the ligamentum flavum, may contribute to this risk, but their role remains unclear. We present 2 cases of lumbar spinal canal stenosis treated with full endoscopic laminectomy. In both cases, dorsal meningovertebral ligaments anchored the dura to the ligamentum flavum and were visible through high-resolution endoscopy. Attempts to remove ligamentum flavum fragments caused dural traction via the dorsal meningovertebral ligament, nearly resulting in laceration. We modified our approach by detaching the dorsal meningovertebral ligament before flavectomy, preventing dural injury and ensuring uneventful recoveries. These cases highlight the importance of recognizing dorsal meningovertebral ligament as a potential risk factor for dural laceration during full endoscopic laminectomy. Although the presence of dorsal meningovertebral ligament cannot be predicted preoperatively, the enhanced visualization provided by full endoscopic spinal surgery allows for intraoperative identification. We recommend careful inspection for dorsal meningovertebral ligament before flavectomy during full endoscopic laminectomy. If identified, these ligaments should be detached prior to ligamentum flavum removal to minimize the risk of dural injury. This approach can significantly enhance the safety of the full endoscopic laminectomy procedure and potentially reduce the incidence of dural complications in full endoscopic spinal surgery.

Acute thrombosis is often observed following the rupture of an intracranial aneurysm, and optimal coil selection during endovascular coiling is challenging. A 75-year-old woman presented with a subarachnoid hemorrhage. Computed tomography angiography revealed aneurysms at the right anterior cerebral artery A2/3 junction and the right middle cerebral artery. Based on vessel wall imaging, the anterior cerebral artery aneurysm was diagnosed as the rupture site. Initial digital subtraction angiography demonstrated a 4.4 × 3.4 × 3.4 mm aneurysm with a 1.6 mm neck. Coil embolization was performed 1 day after diagnostic angiography. Preprocedural angiography revealed significant lumen shrinkage to 2.0 mm, probably due to aneurysmal thrombosis. A 4 mm framing coil was selected based on the initial digital subtraction angiography findings. Contrast extravasation occurred after coil deployment. Immediate protamine administration, blood pressure reduction, and coil embolization with smaller coils in the opacified aneurysm dome achieved hemostasis. Final angiography confirmed complete occlusion, without residual filling or distal thrombus migration. Postoperative computed tomography showed an intracerebral hematoma in the left frontal lobe, which subsequently resolved. The patient recovered without focal neurological deficits and was transferred to a rehabilitation hospital on day 18 with mild attention deficits. This case demonstrates the risk of intraprocedural rupture when coil sizing is selected based on pre-thrombosis dimensions rather than current lumen visualization in rapidly thrombosing aneurysms. When thrombosis reduces the lumen, selecting the coil size based on pre-thrombosis dimensions may increase the risk of intraoperative rupture. Coil size selection should match the currently visualized lumen.

Immature teratomas of the pineal region are a subtype of non-germinomatous germ cell tumors typically associated with early recurrence. Ultra-late recurrence decades after initial treatment is exceedingly uncommon. We report an immature teratoma case in the pineal region that recurred 35 years after subtotal resection and chemoradiotherapy, showing somatic-type malignant transformation into adenoid cystic carcinoma-like adenocarcinoma.

A 16-year-old boy initially underwent ventriculoperitoneal shunting followed by tumor resection, after the pathological confirmation of an immature teratoma (grade 2 according to the ovarian teratoma grading system). A small residual lesion remained, and the patient's condition remained stable for more than a decade, but he was lost to follow-up. At 51 years of age, the patient presented with obstructive hydrocephalus and tumor regrowth. Preoperative serum and cerebrospinal fluid tumor markers levels were normal. An endoscopic biopsy revealed poorly differentiated adenocarcinoma. Resection through an occipital transtentorial approach indicated tumor infiltration into the bilateral thalamus. Histology showed glandular and cartilaginous components with marked atypia and immunohistochemical features resembling adenoid cystic carcinoma, whereas germ cell markers were negative, thus establishing a diagnosis of teratoma with somatic-type malignant transformation. Despite ifosfamide, carboplatin, and etoposide chemotherapy (all at 50% dose) and stereotactic radiosurgery, the disease progressed with leptomeningeal dissemination, and the patient died 613 days after he underwent the second surgery.

This case represents the longest reported interval of recurrence for a central nervous system immature teratoma and highlights the possibility of long-term tumor dormancy followed by malignant transformation. Lifelong surveillance is therefore warranted in patients with residual immature teratomas.

Surfer's myelopathy is a rare, nontraumatic spinal cord injury affecting novice surfers. Although spinal ischemia is considered the primary mechanism, whether the initial insult is arterial or venous remains controversial. We report a case of surfer's myelopathy with magnetic resonance imaging findings suggestive of venous congestion-radiological features that, to our knowledge, have not been previously described.

A previously healthy 23-year-old man developed acute low back pain, progressive lower limb weakness, and bladder and bowel dysfunction after his first surfing experience. Magnetic resonance imaging on admission showed longitudinal T2 hyperintensity from T8/9 to the conus medullaris without abnormalities on diffusion-weighted imaging. On day 2, repeat magnetic resonance imaging again demonstrated no diffusion-weighted imaging changes, whereas the apparent diffusion coefficient map revealed hyperintensity, indicating vasogenic edema. These findings were more consistent with venous rather than arterial ischemia. The patient was treated with antiplatelet and anticoagulation therapy along with rehabilitation and ultimately achieved complete neurological recovery.

This case may represent the first description of magnetic resonance imaging findings suggestive of venous congestion in surfer's myelopathy. Apparent diffusion coefficient hyperintensity in the absence of diffusion restriction may reflect reversible venous ischemia. Incorporating diffusion-weighted imaging and apparent diffusion coefficient maps into routine magnetic resonance imaging protocols for suspected surfer's myelopathy could provide valuable insight into pathophysiology and prognosis.

Ossification of the ligamentum flavum is a pathological condition that can cause progressive myelopathy or severe radiculopathy. Standard surgical management involves direct decompression via posterior resection of the ossification. However, there is a substantial risk of complications, including dural tears and iatrogenic instability. We report a rare case of lumbar ossification of the ligamentum flavum with degenerative spondylolisthesis treated solely by full-endoscopic trans-Kambin's triangle lumbar interbody fusion, aiming for indirect decompression and stabilization, without direct resection of the ossification. A 68-year-old woman had progressive low back pain, bilateral lower extremity radiculopathy, and severe neurogenic claudication, limiting ambulation to 100 m. Imaging revealed Meyerding Grade I L4-L5 spondylolisthesis with dynamic instability and significant canal stenosis due to ossification of the ligamentum flavum, measuring 4.06 mm in maximal thickness. She underwent single-level Kambin's triangle lumbar interbody fusion at L4-L5. Postoperatively, rapid improvement was observed (visual analog scale low back pain: 7→1, leg pain: 8→0; Oswestry Disability Index: 52%→10% at 3 years). Follow-up computed tomography/magnetic resonance imaging demonstrated progressive regression of the ossification, from 4.06 mm to 3.2 mm at 1 year and 1.46 mm at 3 years (64.0%). This case suggests that Kambin's triangle lumbar interbody fusion with indirect decompression is an effective surgical option in lumbar ossification of the ligamentum flavum with segmental instability. The remarkable regression of the ossification suggests that spinal stabilization may suppress pathological mechanical stress, shifting bone remodeling toward resorption, and supports a mechanistic hypothesis. Further prospective studies are warranted to validate this pathophysiological mechanism.

Essential tremor is the most common adult movement disorder, typically presenting with kinetic and postural tremor that interferes with daily activities. For patients unresponsive to medications, surgical options such as radiofrequency thalamotomy, deep brain stimulation, and magnetic resonance-guided focused ultrasound can provide therapeutic benefit.

Magnetic resonance-guided focused ultrasound, an incisionless lesioning modality, has gained clinical use; however, accurate targeting of the ventral intermediate nucleus remains challenging because the nucleus cannot be directly visualized on routine magnetic resonance imaging and exhibits substantial individual variability.

This report describes 2 cases of medication-refractory essential tremor treated with magnetic resonance-guided focused ultrasound ventral intermediate nucleus thalamotomy under structurally complex conditions. One patient had a thick skull with a low skull density ratio, and the other exhibited marked thalamic distortion. In both cases, individualized ventral intermediate nucleus targeting was performed using multimodal imaging that combined a stereotactic planning platform, dentatorubrothalamic tract tractography, and Fast Gray Matter Acquisition T1 Inversion Recovery. The Fast Gray Matter Acquisition T1 Inversion Recovery sequence, which enhances gray-white matter contrast, provided relative contrast of intrathalamic structures, including signal patterns corresponding to the internal medullary lamina. When integrated with connectivity-based dentatorubrothalamic tract tractography, this approach provided complementary information to support anatomically guided targeting.

Stepwise sonication with intraoperative thermal monitoring resulted in substantial tremor reduction without new neurological deficits. These observations suggest that combining Fast Gray Matter Acquisition T1 Inversion Recovery with tractography offers practical, complementary guidance for ventral intermediate nucleus targeting, including in settings without access to advanced commercial integration software. Although limited to 2 patients, this work suggests the value of accessible multimodal imaging for improving confidence in anatomy-informed targeting in magnetic resonance-guided focused ultrasound and potentially other lesioning procedures.

Intracranial schwannomas account for approximately 8% of all primary brain tumors, and the majority arise in the cerebellopontine angle. Ectopic schwannomas that originate from non-cranial nerve sites, such as the dura mater or brain parenchyma, are rare, representing less than 1% of all intracranial schwannomas. These lesions often mimic meningiomas on neuroimaging, making preoperative diagnosis challenging. A woman in her 50s was referred to our department after a brain check-up incidentally revealed a mass lesion extending both above and below the tentorium. Neurological examination was unremarkable. Magnetic resonance imaging demonstrated a well-defined, heterogeneously enhancing extra-axial mass widely attached to the tentorium, suggestive of meningioma. The lesion was completely resected via a suboccipital approach. Histopathological examination revealed spindle-shaped tumor cells with palisading nuclei, positive for S-100 protein and negative for epithelial membrane antigen, confirming the diagnosis of schwannoma. The MIB-1 (Ki-67) labeling index was below 5%, consistent with a benign lesion. Postoperative magnetic resonance imaging confirmed total resection, and the patient's postoperative course was uneventful. No recurrence was observed during a 7-month follow-up period. Tentorial ectopic schwannoma is an extremely rare entity that can closely resemble meningioma both radiologically and intraoperatively. Awareness of this entity is important when evaluating tentorial extra-axial tumors. Although the clinical course is generally favorable following complete resection, careful preoperative evaluation is essential for accurate diagnosis and appropriate management.