The term "arachnoid web" was first mentioned by Mallucci et al.[1] in 1997 as one of the possible causes of idiopathic syringomyelia. They reported that arachnoid webs or pouches create syringomyelia by partially blocking the flow of cerebrospinal fluid (CSF) and can originate from the septum posticum. Then, the disease entity of arachnoid web was verified by Paramore [2] in 2000. He reported two cases of arachnoid web characterized by focal indentation of the dorsal thoracic cord that was not true arachnoid cyst but blocking CSF flow in magnetic resonance imaging (MRI) and computed tomography (CT) myelogram. Both patients presented with weakness of lower extremities and were treated with surgical resection, which produced improvement clinically and radiologically. Since then, a few case reports and studies have been pub-Arachnoid web is a rare disease entity that can cause progressive myelopathy and most often develops at the upper thoracic level. Its pathophysiology is unclear, but may be associated with degeneration of the septum posticum in the dorsal subarachnoid space, which alters the flow of cerebrospinal fluid (CSF) and subsequently leads to cord compression and syringomyelia. It often presents with pain, paresthesia, and extremity weakness. Arachnoid web is diagnosed by a typical pattern of displacement of the spinal cord, known as the scalpel sign, with intact ventral dura mater and disturbed but conserved CSF flow. Arachnoid web should be differentiated from other disease entities sharing the feature of ventral displacement of the dorsal spinal cord, such as arachnoid cyst or spinal cord herniation. The treatment for arachnoid web is surgical resection. We report a 66-year-old female who was diagnosed with arachnoid web in the dorsum of the spinal cord at the T3 level. She had suffered from weakness of both legs for 3 months. She underwent laminectomy of T3 and T4 and the dura was opened. The web was resected and the displacement of the spinal cord then improved.

Objective: This study aimed to compare the radiographic and clinical outcomes between sacral alar iliac (SAI) screw fixation and conventional iliac (CI) screw fixation with a particular focus on the rate of reoperation, surgical site infection (SSI), sacroiliac joint pain, instrument failure, and screw prominence.Methods: Patients who underwent sacropelvic fixation in the authors’ institution from June 2011 to May 2017 were retrospectively investigated. Forty-three patients with SAI screw fixation and 25 with CI screw fixation were included. Preoperative patient and surgical characteristics and postoperative outcomes and complications were analyzed between the SAI and CI groups. Radiographic parameters were analyzed before and after surgery.Results: Lumbosacral fusion rates showed no statistically significant difference between the SAI group and CI groups (90.7% vs. 92.0%, p=0.878). The SAI group showed a significantly good result with regard to SSI compared to the CI group (0% vs. 16%, p=0.016), but had a significantly higher rate of distal screw fracture than the CI group (16.3% vs. 0%, p=0.042).Conclusion: The SAI screw fixation technique could achieve good outcomes of pain relief, deformity correction, and lumbosacral fusion rate with relatively lower complications such as the rates of reoperation, SSI, and screw prominence as compared to the CI screw fixation technique. However, distal instrument failure was observed more frequently in the SAI group, requiring further biomechanical studies.

The aim of this study was to evaluate the clinical outcome of sphenoid wing meningioma with periorbital invasion (PI) after operation. Methods : Sixty one patients with sphenoid wing meningioma were enrolled in this study. Their clinical conditions were monitored after the operation and followed up more than 5 years at the outpatient clinic of a single institution. Clinical and radiologic information of the patients were all recorded including the following parameters : presence of PI, presence of peri-tumor structure invasion, pathologic grade, extents of resection, presence of hyperostosis, exophthalmos index (EI), and surgical complications. We compared the above clinical parameters of the patients with sphenoid wing meningioma in the presence or absence of PI (non-PI), then linked the analyzed data with the clinical outcome of the patients. Results : Of 61 cases, there were 14 PI and 47 non-PI patients. PI group showed a significantly higher score of EI (1.37±0.24 vs. 1.00±0.01, p<0.001), more frequent presence of hyperostosis (85.7% vs. 14.3%, p<0.001), and lower rate of gross total resection (GTR) (35.7% vs. 68.1%, p=0.032). The lower score of pre-operative EI, the absence of both PI and hyperostosis, smaller tumor size, and the performance of GTR were associated with lower recurrence rates in the univariate analysis. However, in the multivariate analysis, the performance of GTR was the only significant factor to determine the recurrence rate (p=0.043). The incidences of surgical complications were not statistically different between the subtotal resection (STR) and GTR groups, but it was strongly associated tumor size (p=0.017). Conclusion :The GTR group showed lower recurrence rate than the STR group without differences in the surgical complications. Therefore, the GTR is strongly recommended to treat sphenoid wing meningioma with PI for the better clinical outcome.