The importance of considering competing risks in recurrence analysis of intracranial meningioma.

BACKGROUND: The risk of recurrence is overestimated by the Kaplan-Meier method when competing events, such as death without recurrence, are present. Such overestimation can be avoided by using the Aalen-Johansen method, which is a direct extension of Kaplan-Meier that accounts for competing events. Meningiomas commonly occur in older individuals and have slow-growing properties, thereby warranting competing risk analysis. The extent to which competing events are considered in meningioma literature is unknown, and the consequences of using incorrect methodologies in meningioma recurrence risk analysis have not been investigated. METHODS: We surveyed articles indexed on PubMed since 2020 to assess the usage of competing risk analysis in recent meningioma literature. To compare recurrence risk estimates obtained through Kaplan-Meier and Aalen-Johansen methods, we applied our international database comprising ~ 8,000 patients with a primary meningioma collected from 42 institutions. RESULTS: Of 513 articles, 169 were eligible for full-text screening. There were 6,537 eligible cases from our PERNS database. The discrepancy between the results obtained by Kaplan-Meier and Aalen-Johansen was negligible among low-grade lesions and younger individuals. The discrepancy increased substantially in the patient groups associated with higher rates of competing events (older patients with high-grade lesions). CONCLUSION: The importance of considering competing events in recurrence risk analysis is poorly recognized as only 6% of the studies we surveyed employed Aalen-Johansen analyses. Consequently, most of the previous literature has overestimated the risk of recurrence. The overestimation was negligible for studies involving low-grade lesions in younger individuals; however, overestimation might have been substantial for studies on high-grade lesions.

How I do it: Sternocleidomastoid sparing approach for the right vertebral artery to common carotid artery transposition.

BACKGROUND: Direct surgery is an important option to treat vertebral artery (VA) stenosis. METHOD: A patient with symptomatic stenosis at the origin of the right VA underwent transposition of the right VA to the common carotid artery (CCA). Using the sternocleidomastoid sparing approach, the VA was anastomosed to the posterior wall of the CCA by twisting the CCA to expose its posterior wall to face the operative field. CONCLUSION: This approach, consisting of securing the proximal VA and then following it to its distal end, not only preserves the sternocleidomastoid muscle but also protects the sympathetic chains and thoracic duct.

[Brain Stem and Para-Brain Stem Lesions].

Surgeries for brainstem lesions and adjacent areas needs meticulous manipulation in the profoundly deep surgical field. Moreover, it is associated with a high risk of complications pertinent to resection. The opportunity for a surgeon to amass extensive surgical experience in these lesions is limited. Additionally, the reduced tissue mobility in the brainstem, compared to other lesions, makes selecting the optimal surgical approach critical. Preoperative simulation is pivotal in surmounting these challenges. However, the limitations of preoperative simulations should be recognized in accurately depicting diminutive vessels and cranial nerves around the brainstem. Incorporating intraoperative anatomical observations and data from intraoperative monitoring into a surgical strategy is imperative. Here, we present three cases in which we believe preoperative simulation was effective; a cavernous hemangioma of the brainstem, trochlear schwannoma, and diffuse midline glioma in the pons.

Primitive Myxoid Mesenchymal Tumor of Infancy With Fatal Hemorrhage In Utero: A Case Report and Literature Review.

Primitive myxoid mesenchymal tumor of infancy (PMMTI) is a rare soft tissue sarcoma in childhood. We present the case of a newborn male who experienced a severe hemorrhage in utero from the tumor on the scalp. He died at the age of 24 hours owing to hemorrhagic shock. The tumor was posthumously diagnosed as PMMTI. A literature search indicated that cases of severe hemorrhage from soft tissue sarcomas in utero or at birth are limited to infantile fibrosarcoma. This is the first case of PMMTI with massive hemorrhage. Clinicians must be aware of hemorrhagic complications of PMMTI.

[Mesenchymal and Non-meningothelial Tumors Involving the Central Nervous System].

In the World Health Organization Classification of Brain Tumors Fifth Edition, mesenchymal non-meningothelial tumors involving the central nervous system are divided into three major categories: soft tissue tumors, chondro-osseous tumors, and notochordal tumors. Soft tissue tumors are classified into four groups: fibroblastic and myofibroblastic tumors, vascular tumors, skeletal muscle tumors, and tumors of uncertain differentiation. This article will focus on solitary fibrous tumors(SFTs), which are frequently encountered clinically and continue to undergo classification revisions in the 5th edition, and outline the three newly added histological diagnoses. Although SFTs and hemangiopericytomas occur throughout the body, including the central nervous system, nomenclatures have been different between the classifications of "Tumours of Soft Tissue and Bone" and "Tumours of the Central Nervous System." The latest nomenclature is "SFT" in accordance with the nomenclature of bone and soft-tissue tumors. In addition, three new diagnoses, which are intracranial mesenchymal tumor FET-CREB fusion-positive, CIC-rearranged sarcoma, and primary intracranial sarcoma DICER1-mutant, have been defined based on genetic abnormalities in tumors of uncertain differentiation.

Male sex and presence of preoperative symptoms are associated with early recurrence of WHO grade I meningiomas after surgical resection: analysis from the nationwide Brain Tumor Registry of Japan.

This study aimed to assess the risk factors for the recurrence of WHO grade I intracranial meningiomas using the Brain Tumor Registry of Japan (BTRJ) database. We extracted the data of 4641 patients with intracranial WHO grade I meningiomas treated only by surgical resection between 2001 and 2008. We conducted complete data analysis (n = 3690) and multiple imputation analysis (n = 4641) to adjust for missing data on tumor size. The influence of factors including age, sex, size, extent of resection, location, and preoperative symptoms on PFS was assessed. Univariate analyses of the complete data set showed that age did not affect PFS; however, male sex (p < 0.001), tumor size ≥ 30 mm (p < 0.001), low extent of resection, tumor location at the skull base (p < 0.001), and the presence of preoperative symptoms (p < 0.001) were risk factors for a significantly shorter PFS. Multivariate analysis demonstrated that male sex (p < 0.001) and presence of preoperative symptoms (p = 0.027) were independent risk factors for shorter PFS alongside large tumor size (p < 0.001) and non-gross total resection (p < 0.001). These results were confirmed for the imputed dataset. While most previous large nationwide studies of meningiomas have evaluated overall survival, progression-free survival has yet to be thoroughly examined. This study suggests that even histologically benign meningiomas may have a sex difference in postoperative behavior. This observation may provide clues to understanding the mechanism of meningioma cell proliferation.

The optimal management of ruptured basilar artery dissecting aneurysms: a case series and scoping review.

The natural history of ruptured basilar artery dissecting aneurysms (BADAs) remains unclear compared to that of ruptured vertebral artery dissecting aneurysms (VADAs). In this study, we investigated the natural history and optimal management of ruptured BADAs. We identified 17 patients with ruptured BADA among 4586 patients with aneurysmal subarachnoid hemorrhage (SAH) treated in seven participating hospitals. A scoping literature review was undertaken to investigate prognostic factors. Six patients among the profiled patients (35.3%) died, all with poor SAH grades (World Federation of Neurological Societies Grade IV and V). Rebleeding after admission was observed in three patients (17.6%) with poor SAH grades. Aggressive treatment and conservative management were initiated in seven and ten patients, respectively. Patients with good SAH grades had significantly higher favorable treatment outcomes than those with poor grades (83.3% vs. 9.1%, P = 0.005). Moreover, based on a scoping review of 158 cases with ruptured BADA, including the patients from our series, approximately 90% of patients with good SAH grades had favorable outcomes. A good SAH grade and no rebleeding after admission were favorable prognostic factors (P < 0.0001 and P = 0.002, respectively). The rebleeding rates were 20.2%, 13.3%, and 6.3% for dilated, pearl and string, and stenotic lesions, respectively. We concluded that the natural history of isolated ruptured BADAs may be better than that of VADAs. Although definitive treatment, if possible, is undoubtedly important, conservative management with careful radiological follow-up for morphological changes might be a viable option for patients in good clinical condition and with non-dilated lesions.

A case of aggressive pituitary neuroendocrine tumour with extremely rapid progression: possible diagnostic value of TERT promoter methylation.

Most pituitary adenoma/neuroendocrine tumours (PitNET) are histologically benign and grow slowly; however, a subset of these tumours exhibit a more aggressive clinical course characterized by local invasiveness and early recurrence. These high-risk PitNETs often require multiple surgeries and radiation over several years and may eventually acquire carcinomatous characteristics, such as metastasis in some cases. Herein, we report a rare case of PitNET causing oculomotor paresis with extremely rapid recurrence only 3 months after initial surgery, followed by lethal liver metastasis. Preoperative magnetic resonance imaging and intraoperative findings were consistent with typical PitNETs, other than moderate invasion of the cavernous sinus. Pathological examination of the specimen obtained from the initial transsphenoidal surgery revealed increased mitosis and elevated rates of cells positive for Ki-67 and p53. Based on the immunohistochemical assessment for transcription factors and pituitary hormones, the diagnosis was determined to be a silent sparsely granulated corticotroph PitNET with focal malignant transformation. Aggressive features represented by Ki-67 and p53 positivity were more robust in recurrent and metastatic specimens, but hormone immunostaining was decreased. Epigenetic analysis revealed methylation of the telomerase reverse transcriptase (TERT) promoter in the tumour, resulting in TERT upregulation. Despite extensive research, markers for distinguishing extremely aggressive PitNETs have not been determined. Although further analysis is needed, our case demonstrates the possible usefulness of assessing TERT promoter methylation status in the stratification of recurrence risk in extremely high-risk variants of PitNET.

[Latest Findings on Meningioma:WHO grades 1/2/3].

While most meningiomas are histologically benign tumors, higher grade meningiomas classified as WHO grades 2 and 3 are not always amenable to the standard treatment. To accurately assess the biological characteristics and prognosis of the tumor, the WHO classification of meningiomas has been continuously revised based on the latest findings. This article describes the recent modifications of the WHO classification of meningiomas. In the 2021 WHO classification, molecular diagnosis was considered more important and it was integrated into the classification as a stand-alone criterion of some subtypes. As for treatment, surgical resection is the mainstay treatment for meningiomas of all WHO grades while the importance of radiation therapy should be emphasized, especially for skull base meningiomas, to balance the surgical risk and for functional preservation. Among the new surgical techniques, endoscopic resection of midline skull base meningiomas has been established over the last decades. In addition, several notable new insights to control high-grade meningiomas based on prospective observational studies are introduced in this article.

Effect of adjuvant radiotherapy after subtotal resection for WHO grade I meningioma: a propensity score matching analysis of the Brain Tumor Registry of Japan.

PURPOSE: This study aimed to improve the understanding of the role of adjuvant radiotherapy (AR) after subtotal resection (STR) of World Health Organization (WHO) grade I meningiomas. METHODS: We retrospectively reviewed the Brain Tumor Registry of Japan database. Among 7341 patients diagnosed with intracranial meningioma during 2001-2008, we identified 406 patients with WHO grade I meningioma treated with STR as initial treatment. Data on progression-free survival (PFS) were assessed for their relevance to clinical factors including age, sex, tumor location and size, presence of preoperative symptoms, and AR. RESULTS: AR was administered for 73 patients (18.0%). Regrowth occurred in 90 cases (22.2%) during the median follow-up period of 6.0 years (interquartile range, 2.7-7.7 years). Multivariate Cox regression analysis of the entire cohort showed that no AR was associated with significantly shorter PFS (hazard ratio [HR] 2.52, 95% confidence interval [CI] 1.33-5.42, p = 0.004). The therapeutic effect of AR was confirmed for skull base, but not non-skull base, meningiomas (p = 0.003 and 0.69, respectively). Propensity score matching analysis balanced the influence of confounding factors to generate AR+ and AR- cohorts of 73 patients each. PFS was significantly longer in the AR+ cohort than in the AR- cohort (HR 3.46, 95% CI 1.53-8.59, p = 0.003). Subgroup analysis demonstrated the favorable effect of AR only for skull base meningiomas. CONCLUSIONS: Our study revealed that AR improves tumor control after STR in WHO grade I meningiomas. However, this beneficial effect might be limited to skull base meningiomas.

Carotid endarterectomy restores decreased vision due to chronic ocular ischemia.

BACKGROUND: The therapeutic effect of carotid endarterectomy (CEA) on visual disturbance caused by chronic ocular ischemia due to carotid artery stenosis has not been validated. This prospective observational study aims to investigate whether CEA is associated with an increase in ocular blood flow (OBF) and postoperative visual improvement. METHODS: In total, 41 patients with carotid artery stenosis treated by CEA between March 2015 and September 2018 were enrolled in this study. OBF was evaluated by laser speckle flowgraphy, which can measure the mean blur ratio (MBR) which is well correlated to the absolute retinal blood flow. Visual acuity was assessed before and after CEA by subjective improvement and objective visual assessment using CSV-1000, an instrument used to test contrast sensitivity. RESULTS: OBF increased after CEA on the operated side (mean MBR 33.5 vs 38.2, p < 0.001) but not on the non-operated side (mean MBR 37.8 vs 37.5, p = 0.50). After CEA, 23 patients (56.1%) reported subjective visual improvement on the operated side. The mean CSV-1000 score among the patients with increased OBF after CEA (5.44 vs 5.88, p = 0.04) but not among those without increased OBF (5.48 vs 5.95, p = 0.09). The mean CSV-1000 scores increased significantly after CEA in 18 patients with decreased vision and decreased OBF (4.51 vs 5.37, p < 0.001), but not in the 23 patients without those (6.19 vs 6.31, p = 0.6). CONCLUSION: CEA may successfully reverse visual dysfunction caused by chronic ocular ischemia due to carotid artery stenosis by increasing OBF.

Best Motor Response Predicts Favorable Outcome for "True" WFNS Grade V Patients with Aneurysmal Subarachnoid Hemorrhage.

BACKGROUND: The universal application of ultra-early surgery for World Federation of Neurological Societies (WFNS) grade V aneurysmal subarachnoid hemorrhage (aSAH) patients may lead to the increased implementation of unnecessary treatment. Therefore, this study aimed to refine the patient selection process for timely definitive treatment. METHODS: From January 2011 to March 2020, a total of 517 aSAH patients were treated at our institution. Among these, 177 aSAH patients with WFNS grade V on admission were identified from our database. Patients with improved grades in response to the initial supportive treatment, with clinical or radiological signs of herniation, and with irreversible signs of brain damage such as bilaterally dilated pupils and global ischemia on follow-up CT scan were excluded. The outcome of definitive treatment for 54 patients without herniation who remained with WFNS grade V after the initial supportive treatment were analyzed to seek any factor for a favorable outcome (modified Rankin scale 0-2). RESULTS: Among 54 patients, 19 (35.2%) had a favorable outcome after a definitive treatment. Multivariate logistic regression analysis showed that the best motor response (BMR) 4 on Glasgow Coma Scale was significantly associated with favorable outcomes (odds ratio, 3.76; 95% confidence interval, 1.09-13.0, p = 0.03). The positive predictive value of BMR 4 was 48.3%. CONCLUSIONS: Albeit being simple, BMR 4 may facilitate the prompt aggressive treatment for patients with WFNS grade V including those with "true" grade V who do not have any clinical and radiological signs of herniation.

Superficial temporal artery-superior cerebellar artery bypass and trapping of a fusiform aneurysm using intradural anterior petrosectomy: technical case report and anatomical study.

Aneurysms at the distal portion of the superior cerebellar artery (SCA) are very rare. Because of the deep location and a propensity for nonsaccular morphology, aneurysm trapping or endovascular occlusion of the parent artery are the usual treatment options, which are associated with varying risks of ischemic complications. The authors report on a 60-year-old woman who had a 3.5-mm unruptured aneurysm in the lateral pontomesencephalic segment of the SCA with a significant interval growth to 8 mm. Direct surgical intervention comprising trapping of the aneurysm through a subtemporal approach and intradural anterior petrosectomy combined with revascularization of the distal SCA using the superficial temporal artery (STA) was performed. This approach provided sufficient space for the bypass instruments to be introduced into the deep surgical field at a more favorable angle to enhance microscopic visualization of the anastomosis with minimal retraction of the temporal lobe. The patient was discharged with no neurological deficit. Preservation of the blood flow in the distal SCA should be attempted to minimize the risk of ischemic injury, particularly when the aneurysms arise in the anterior or lateral segment of the SCA. The authors demonstrate the safety and effectiveness of the intradural anterior petrosectomy for STA-SCA bypass along with a relevant anatomical study.

The pathogenesis of intracranial growing teratoma syndrome: proliferation of tumor cells or formation of multiple expanding cysts? Two case reports and review of the literature.

PURPOSE: Growing teratoma syndrome (GTS) is a rare clinical phenomenon defined as the paradoxical growth of mature teratoma components during or after chemotherapy. The mechanism of this phenomenon is not well understood. We present two cases of pineal mixed germ cell tumors that exhibited the similar course to GTS and speculate its pathogenesis. CASE REPORT: The first case was accompanied by slightly elevated alpha-fetoprotein (8.8 ng/ml; normal <6.6 ng/ml). The tumor rapidly grew from 1.5 to 2.7 cm in diameter within 4 weeks. Despite this rapid preoperative growth, thorough pathological investigation found only mature teratoma components along with multiple micro- and macro-cysts. The other case was diagnosed as a pure germinoma based on biopsy and serological examinations. During three courses of chemotherapy, this tumor presented a honeycomb-like appearance on magnetic resonance (MR) images and an exceptionally rapid enlargement. Second-look surgery confirmed the histological diagnosis of a mature teratoma. In both cases, meticulous pathological examination of all whole tumor sections revealed no malignant histological features, and the MIB-1 labeling indices were too low to account for the extremely rapid tumor growth. Instead, both MR images and histological findings demonstrated a predominant formation of multiple cysts. CONCLUSION: We speculate that this paradoxical growth might not be tumorous proliferation but instead the formation and expansion of multiple cysts inside mature teratoma components and that the presence or absence of growth might be a subsidiary phenomenon. Our hypothesis appears consistent with the characteristic radiological findings of GTS reported in the literature.

The influence of age on the histological grading of meningiomas.

This study was undertaken to assess the relationship between the age of patients at the time of their surgery and histological grading of meningiomas. A retrospective review was conducted for 1,083 consecutive patients with meningiomas who had surgical removal between January 1991 and December 2006. Histological grading for each tumor was done utilizing the WHO classification for meningiomas. The incidence of WHO grade II or III tumors between the elderly and the non-elderly groups was compared. The mean age at diagnosis for the WHO grade I, II, and III tumors was 55.1 (±14.79), 59.0 (±15.54), and 64.3 years (±13.28) (p value = 0.007), respectively. We found that 11.9 % of meningiomas diagnosed after the age of 60 years was WHO grade II or III, while this value was only 6.9 % for patients 60 years or younger (p = 0.0006). Our study showed that the combined incidence of WHO grade II and III meningiomas increases as age advances. We believe that this constitutes an important piece of information requiring neurosurgeons to carefully and continuously observe the elderly patients harboring meningiomas.

Analysis of risk factors for chronic subdural haematoma recurrence after burr hole surgery: optimal management of patients on antiplatelet therapy.

OBJECTIVE. Not much is known about surgical management of patients with chronic subdural haematoma (CSDH) treated with antiplatelet or anticoagulant therapy. The aims of this study were to review the surgical outcomes of patients with CSDH and assess the risks of antiplatelet in their surgical management. METHODS. We retrospectively analysed 448 consecutive patients with CSDH treated by one burr hole surgery at our institution. Among them, 58 patients had been on antiplatelet therapy. We discontinued the antiplatelet agents before surgery for all 58 patients. For 51 of these 58 patients (87.9%), early surgery was performed within 0-2 days from admission. We analysed the association between recurrence and patient characteristics, including history of antiplatelet or anticoagulant therapy; age (< 70 years or ≥ 70 years); side; history of angiotensin receptor II blocker, angiotensin converting enzyme blocker, or statin therapy; and previous medical history of head trauma, infarction, hypertension, diabetes mellitus, haemodialysis, seizure, cancer, or liver cirrhosis. RESULTS. Recurrence occurred in 40 patients (8.9%), which was one of the lowest rates in the literature. Univariate analysis showed that only the presence of bilateral haematomas was associated with increased recurrence rate while antiplatelet or anticoagulant therapy did not significantly increase recurrence risk. Also, the recurrence rate from early surgery (0-2 days from drug cessation) for patients on antiplatelet therapy was not significantly higher than that from elective surgery (5 days or more after drug cessation). However, multivariate analysis revealed that previous history of cerebral infarction was an independent risk factor for CSDH recurrence. CONCLUSIOns. Our overall data support the safety of early surgery for patients on the preoperative antiplatelet therapy without drug cessation or platelet infusion. Patients with a previous history of infarction may need to be closely followed regardless of antiplatelet or anticoagulant therapy.

[A review of treatment outcomes for intracranial abscess at our institution].

BACKGROUND: Intracranial abscesses account for 2% of the intracranial mass even in advanced countries. Because of the variety of causative organisms and symptoms, a standard treatment for intracranial abscess has not yet been established. MATERIALS AND METHODS: We retrospectively reviewed the treatment outcomes for intracranial brain abscess and subdural abscess to assess the risk factors for poor prognosis and problems related to treatment. RESULTS: In total, 28 patients were included in this study. Preceding craniocervical infections were found in 35.7% of patients. In 39.3% of patients, causative organisms were not identified. The treatment outcome evaluated using the modified Rankin Scale was 0 in 17 patients, 1 in 1 patient, 2 in 2 patients, 4 in 3 patients, 5 in 1 patient, and 6 in 4 patients. All mortality was noted in patients older than 60 years. Advanced age and the development of ventriculitis were significantly associated with poor outcome, i.e., a modified Rankin Scale score of 4 or worse. In contrast, the presence of fever or headache as initial symptoms, severity of neurological deficit, location of the abscess, and lack of identification of causative organism were not related to poor outcome. Compared with our previous treatment results, diffusion-weighted MR imaging has significantly contributed to the improvement of outcomes. CONCLUSION: Early administration of antibiotic therapy based on MR findings was critical in obtaining a good outcome in the treatment of brain abscess. Based on our experience, treatment should be continued, even for patients in a critical condition.

Surgical Outcomes following Reoperation for Recurrent Intracranial Meningiomas.

Background: We sometimes encounter refractory meningioma cases that are difficult to control, even after achieving a high resection rate or following radiation therapy (RT). In such cases, additional surgical resection might be attempted, but reports regarding outcomes of re-do surgery for recurrent meningiomas are scarce. Methods: This study was a retrospective review of patients who underwent re-do surgery for recurrent meningiomas. The risks of re-doing surgery were statistically analyzed. A comparative analysis between the patients who underwent primary surgery for intracranial meningiomas was also performed. Twenty-six patients underwent re-do surgeries for recurrent meningiomas. Results: At first re-do surgery, gross total resection was achieved in 20 patients (77%). The disease-free survival rate after the first re-do surgery was calculated as 73/58/44% at 1, 2, and 5 years, respectively. A significant factor affecting longer disease-free survival was WHO Grade 1 diagnosis at first re-do surgery (p = 0.02). Surgery-related risks were observed in 10 patients presenting a significant risk factor for skull base location (p = 0.04). When comparing with the risk at primary surgery, the risks of surgical site infection (p = 0.04) and significant vessel injury (p < 0.01) were significantly higher for the re-do surgery. Conclusions: Re-do surgery could increase surgery-related risks compared to the primary surgery; however, it could remain a crucial option, while the indication should be carefully examined in each case.

Effectiveness of S-Shaping of the Tip of the FUBUKI Guiding Catheter to Match the Shape of the Cervical Internal Carotid Artery in Anterior Circulation Cerebral Aneurysm Embolization.

Objective: During cerebral aneurysm embolization of the anterior circulation, the guiding catheter (GC) should be placed as distally as possible in the cervical internal carotid artery (ICA) to secure the maneuverability of the microcatheter and distal access catheter. However, if the shape of the tip of the GC does not appropriately match the course of the ICA, blood stasis might occur. We investigated whether shaping the tip of the GC into an S-shape would allow more stable catheterization to the distal ICA than the conventional GC with an angled tip. Methods: We included patients with cerebral aneurysms of the anterior circulation who were treated at our institution from April 2019 to April 2021. First, we evaluated the cervical ICA course in these patients through cerebral angiography and classified the courses into type S, type I, and type Z. Then, we focused on the most frequently encountered type-S cervical ICA to investigate the forging effect of the GC tip into an S-shape. We evaluated the lateral view of the carotid angiograms to examine whether the catheter tip reached the foramen magnum (FM) without interrupting ICA blood flow. The effects of age, sex, side, a history of hypertension and smoking, and an S-shape modification of the GC tip on the outcome of GC placement were analyzed. Results: A total of 67 patients were included in this study. The tip of the GC was placed at the FM in 27 cases. Among these factors, only the S-shape modification was significantly associated with whether the GC could be placed at the level of the FM (p <0.0001). Conclusion: By forging the tip of the GC into an S-shape, the GC can be safely advanced to the distal part of the cervical ICA, which may contribute to the improved maneuverability of microcatheters.

Differences in the Demographics and Clinical Characteristics between the Ossification of the Posterior Longitudinal Ligament and Ossification of the Ligamentum Flavum in Patients Who Underwent Thoracic Spinal Surgery for Compressive Myelopathy.

Ossification of the posterior longitudinal ligament (OPLL) and ossification of the ligamentum flavum (OLF) are related diseases associated with the ossification of spinal ligaments that can occasionally lead to thoracic myelopathy. We retrospectively analyzed the clinical data of 34 consecutive patients who underwent thoracic spinal surgeries for OPLL and/or OLF at our hospital between July 2010 and June 2022, and statistically compared data between patients with thoracic OPLL (TOPLL; n = 12) and those with thoracic OLF (TOLF; n = 22). The mean age of the TOPLL group was significantly lower than that of the TOLF group (53.7 vs. 68.4 years). The TOPLL group exhibited a greater female predominance than the TOLF group (58.3% vs. 18.2%). The median body mass index of the TOPLL group was significantly higher than that of the TOLF group (33.0 vs. 26.0 kg/m2). Patients with TOPLL significantly required instrumented fusion and repetitive surgical intervention more than those with TOLF (83.3% vs. 9.1%; 50.0% vs. 0.0%). Although neurological deterioration just after the intervention was more common in patients with TOPLL (41.7% vs. 4.6%), no difference was observed in thoracic Japanese Orthopaedic Association score and recovery rate in the chronic phase between TOPLL and TOLF. The TOPLL group had a younger onset, female dominance, and a greater degree of obesity when compared with the TOLF group. The surgery for TOPLL is challenging, considering that it requires long-range decompression and fusion, subsequent operations, careful management, and long-term follow-up, when compared to TOLF, which necessitates only simple decompression.