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Objective Foramen magnum decompression (FMD) remains the first-line treatment for Chiari malformation type I associated with syringomyelia, although consistent approaches are not used. However, there are few reports on a persistent or recurrent syrinx or worsening neurologic symptoms after FMD. Methods We retrospectively reviewed medical records of patients who attended Xuanwu Hospital between January 2018 and July 2019 with persistent or recurrent syringomyelia after FMD. Results All 8 patients had syringomyelia preoperatively with a mean disease course of 43 (range, 3–120) months and underwent FMD. The presenting symptoms improved in 1 patient. There was radiologic evidence of decreased syrinx size in 1 patient. Worsening syringomyelia presented at a median of 65 (range, 7–168) months after the primary FMD. Secondary decompression was performed in all patients. A structural, pathological cause for the first FMD failure was identified in all cases at the time of the second decompression. Symptoms were resolved in all patients after repeat decompression surgery. Radiologically, 6 patients had a decrease in syringomyelia size. The level of the upper segment of the syringomyelia was higher in 7 of our revision patients, among which 6 patients had a decrease in syringomyelia size. The median follow-up duration after the secondary decompression was 11.5 (range, 6–22) months. Conclusions Adults with persistent syringomyelia after FMD and the higher level of the upper segment of the syringomyelia often have a surgically remediable structural cause. The beneficial effect of a secondary decompression should be considered and guide the decision-making of patients with Chiari malformation type I–related syringomyelia.

Objective To assess the value and limitation of cervical traction in the evaluation of the reducibility of atlantoaxial dislocation (AAD) and basilar invagination (BI) using the intraoperative O-arm. Methods A total of 22 patients with hyperextensive, irreducible AAD were included. The cervical traction test under general anesthesia was performed, and the degree of reduction was evaluated using the O-arm before the operation started. The traction effects both vertically and horizontally were evaluated. All cases then underwent modified direct posterior reduction and fixation. Clinical outcomes were evaluated using the Japanese Orthopaedic Association (JOA) scale. Radiologic measurements included the anterior atlantodental interval, the distance of odontoid tip above Chamberlain line, and the clivus–canal angle. Magnetic resonance imaging signal changes, size of syringomyelia, and the space ventral to medulla also were used to evaluate the postoperative reduction result. Results After the cervical traction test, 7 patients achieved incomplete reduction, 5 achieved only vertical reduction, 6 achieved only horizontal reduction, and 4 achieved complete reduction in both horizontal and vertical orientations as assessed by the O-arm. All patients underwent a direct reduction technique. The mean JOA score increased from 11.1 to 14.5. Complete reduction of AAD and BI were achieved in 19 patients (86.4%), with partial reduction achieved in 3 (13.6%). Sufficient cerebrospinal fluid space anterior to the medulla with improved JOA score was achieved in the 3 partially reduced patients. Conclusions With the innovations of direct posterior reduction techniques, cervical traction under anesthesia may not sufficiently predict the reducibility of BI and AAD. Cervical traction still plays an important role during the direct posterior reduction procedure.

Congenital hypoplasia or aplasia of the A1 segment of the anterior cerebral artery is associated with an increased incidence of berry aneurysms at the anterior communicating artery (ACoA) complex. We analyzed the factors contributing to ACoA aneurysm rupture.We retrospectively analyzed the data of patients with ACoA aneurysms who had undergone cerebral angiography from July 2008 to January 2020. The risk factors for rupture were identified using univariate and multivariate logistic regression models. We used the imaging data of patients without intracranial aneurysms as the control population.We confirmed 253 aneurysms in 253 patients, including 137 men (54.2%) and 116 women (45.8%), with a mean age of 54.6 ± 12.7 years. Of the 253 aneurysms, 218 (86.2%) were ruptured and 35 (13.8%) were unruptured, with a mean diameter of 4.56 ± 1.96 mm and 3.24 ± 1.79 mm, respectively. Of the 253 aneurysms, 176 (69.6%) were5 mm in diameter, 146 (83%) of which were ruptured. Of the 253 patients, 141 (55.7%) exhibited A1 segment hypoplasia or aplasia: 106 (41.9%) on the right side of the circle of Willis and 35 (13.8%) on the left. Multivariate logistic regression analysis identified the aneurysm diameter (odds ratio, 4.11; 95% confidence interval, 1.601-16.07; P = 0.003) and age65 years (odds ratio, 0.17; 95% confidence interval, 0.062-0.48; P0.001) as independent predictors of rupture.ACoA aneurysms are small (5 mm) and have a high risk of rupture. A1 segment hypoplasia or aplasia is a risk factor for ACoA aneurysm formation; however, it was uncorrelated with aneurysm diameter or rupture risk. The strongest independent risk factors for rupture were age65 years and aneurysm diameter.

Objective To identify clinical factors predicting the development of myelopathy in cervical ossification of the posterior longitudinal ligament (OPLL) patients with radiculopathy. Methods We retrospectively reviewed 83 cervical OPLL patients who presented with radiculopathy. On the basis of the symptoms and physical findings, we divided patients into 2 groups: myelopathy group and nonmyelopathy group. Demographic, clinical, and radiologic characteristics were reviewed and analyzed among the 2 groups. Predictors for the development of myelopathy were assessed via univariate and multivariate analysis. Results Univariate analysis demonstrated that a high occupying ratio and the presence of an intramedullary high signal were risk factors for development of myelopathy from radiculopathy in OPLL patients. Multivariate analysis further identified that a high occupying ratio was the only independent predictor (odds ratio 1.05, 95% confidence interval 1.003–1.091, P = 0.035). The cervical range of motion and minor trauma were not related to the development of myelopathy in our study. Conclusions Nonmyelopathic OPLL patients with radiculopathy and a high occupying ratio were at higher risk of developing myelopathy, and surgical intervention should be recommended in these cases. However, for elderly patients with significant comorbid conditions, the risks and benefits of surgery should be carefully considered.