An infratentorial dural arteriovenous fistula mimicking cervical myelopathy: A case report.

Dural arteriovenous fistulas may have insidious clinical presentations and are often challenging to diagnose. A small number of cases have been associated with perimedullary venous congestion and cord oedema, mimicking common pathologies, such as cervical myelopathy. We describe a case report of a patient presenting with a constellation of symptoms and radiological signs mimicking C5/6 cervical myelopathy secondary to disc herniation. The patient was managed with anterior cervical discectomy and fusion, with postoperative neurological deterioration unresponsive to steroid therapy. This prompted further investigation of other pathologies. An infratentorial Cognard 5 and Borden type 3 dural arteriovenous fistula was diagnosed on 6-vessel DSA and managed with onyx embolization. Marked improvement of neurological symptoms, notably bilateral lower limb weakness, was achieved postoperatively. In summary, this case demonstrates the importance of considering alternative, less common pathologies that involve the cervical spinal cord when neurological improvement is not achieved following decompressive surgery for cervical myelopathy.

The surgical management of intraoperative intracranial internal carotid artery injury in open skull base surgery-a systematic review.

Intraoperative internal carotid artery (ICA) injury during open skull base surgery is a catastrophic complication. Multiple techniques and management strategies have been reported for endoscopic skull base surgery; however, the literature on managing this complication in open skull base surgery is limited. To perform a systematic review and give an overview of the different techniques described to manage this complication intraoperatively, a systematic review was conducted in PubMed, Ovid Medline, Ovid Embase and Scopus for literature published until July 2021. Titles and abstracts were screened. Studies meeting prespecified inclusion criteria were reviewed in full. PRISMA guidelines were strictly adhered to. Out of 4492 articles, only 12 articles could be included, reflecting an underreporting of open skull base ICA injuries. Multiple techniques can be used depending on the location and size of the injury as well as the surgeon's experience. Described techniques include the following: a primary repair via a micro-suture or nonpenetrating clips; wrapping or plugging; coating; occlusion of the parent artery with or without a bypass; packing with further endovascular management. A treatment algorithm is proposed.

Syringomyelia intermittens: highlighting the complex pathophysiology of syringomyelia. Illustrative case.

BACKGROUND: Chiari Type I malformation (CM1) is a disorder recognized by caudal displacement of the cerebellar tonsils through the foramen magnum and into the cervical canal. Syringomyelia is frequently found in patients with CM1, but the pathophysiology of syringomyelia remains an enigma. As a general consensus, symptomatic patients should be treated and asymptomatic patients without a syrinx should not be treated. Mildly symptomatic patients or asymptomatic patients with a syrinx, on the other hand, pose a more challenging dilemma, as the natural evolution is uncertain. For many surgeons, the presence of a syrinx is an indication to offer surgery even if the patient is asymptomatic or mildly symptomatic. OBSERVATIONS: The authors describe an illustrative case of a 31-year-old female with an incidental finding of a CM1 malformation and cervical syrinx in 2013. Conservative management was advocated as the patient was asymptomatic. Monitoring of the syrinx over a course of 8 years showed resolution, followed by reappearance and finally a complete resolution in 2021. A review of the literature and the possible pathophysiology is discussed. LESSONS: The unusual course of this patient highlights the importance of guiding treatment by clinical symptoms, not radiological findings. Furthermore it reflects the complexity of the pathophysiology and the uncertain natural history of syringomyelia.

Chitosan Dextran gel as an anti adhesion agent in a postlaminectomy spinal sheep model.

INTRODUCTION: Post-operative peridural adhesions increase morbidity after neurosurgical procedures. Aim of this study is to assess safety and efficacy of Chitosan-Dextran (CD) gel as an anti-adhesion agent in a spinal laminectomy sheep model. METHODS: Eighteen sheep were used in this study with 6 animals in each treatment arm (namely, CD gel, Gelfoam paste and normal saline control). Posterior lumbar laminectomy was performed in all animals and the dura was exposed intact. Test agents were applied over the exposed dura and the wound was closed in layers. Sheep were euthanized at the end of three months. MRI spine was performed after euthanasia to assess epidural fibrosis. Adhesion in the spinal specimen was assessed by Peel test and histopathology was used to assess safety of the agents. RESULTS: Average scores for the Peel test for CD gel, Gelfoam and normal saline control groups were 1.16 (95% CI, 0.5-1.7), 1.5 (95% CI, 0.6-2.3) and 3 (95% CI, 2.1-3.8) respectively. There was significant reduction in adhesions between treatment and normal saline treated groups (p=0.0292), with no difference between Gelfoam and CD gel groups (p=0.56). Average scores on MRI for CD gel, Gelfoam and normal saline groups were 1.4 (95% CI, 0.9-1.8), 1.5 (95% CI, 1.2-1.8) and 1.6 (95% CI, 1.3-1.8) respectively, with no significant difference in fibrosis amongst (p=0.2992). Histopathology did not show any adverse effects. CONCLUSION: CD gel is an effective agent to reduce epidural adhesions with a good safety profile in neural tissue.

The efficacy and safety of chitosan dextran gel in a burr hole neurosurgical sheep model.

BACKGROUND: Achieving and maintaining haemostasis is of paramount importance in neurosurgery. Chitosan has been shown in both animal and human models to be significantly effective in haemostasis as well as in reducing adhesion formation. OBJECTIVES: To evaluate the haemostatic potential and to study histopathological changes caused by novel chitosan dextran gel in a neurosurgical sheep model. METHOD: Ten sheep underwent neurosurgical burr hole procedure. Bleeding control was tested at the level of bone, dura and brain separately with both chitosan gel and Gelfoam paste on separate burr holes. Baseline bleeding was measured at the time of injury using the Boezaart scale, and then every 2 min after the application of each agent until complete haemostasis or 10 min, whichever was earlier. Safety was assessed through MRI scans and histopathological analysis. RESULTS: Mixed modeling showed no statistical difference in time to haemostasis between chitosan gel and Gelfoam paste (means of log-normalized areas under the curve were 1.3688 and 1.3196 respectively) for each burr hole (p = 0.7768). Logistic regression modeling showed that Chitosan significantly decreased the incidence of bleeding beyond the first time point measured after application of the treatment when compared to Gelfoam (OR = 2.7, p = 0.04). Average edema volume (cm(3)) on post-operative MRI was 0.97 for Gelfoam and 1.11 for (p = 0.49) while average histology scores were 2.5 for Gelfoam versus 3.3 for chitosan (p = 0.32). CONCLUSION: Chitosan dextran gel is an effective haemostatic agent to control bleeding in brain tissue. It is safe and nontoxic to neural tissue.

Endoscopic endonasal resection of anterior skull base meningiomas.

OBJECTIVE: Anterior cranial fossa (ACF) meningiomas are difficult to surgically manage. Endoscopic transnasal approaches have increasingly been used as a minimally invasive route and thus offer significant advantages. However, a paucity of literature describing the intraoperative challenges and postoperative outcomes of this technique still exists. STUDY DESIGN: Case series with chart review. SETTING: The Royal Adelaide Hospital, Flinders Medical Centre, Wellington Hospital. SUBJECTS AND METHODS: Fifteen consecutive patients who underwent endoscopic resection of ACF meningiomas between 2004 and 2010 by the South Australian and Wellington Skull Base Units. Demographic and clinical information was compiled by reviewing patient charts and operation notes. Safety and efficacy of the procedure, role of a team approach, and areas for further improvement were analyzed. RESULTS: Of the patients, 87% were women. Tumor locations: 8 olfactory groove, 2 tuberculum sellae, 1 clinoidal, 1 jugum sphenoidale, 1 planum sphenoidale, 1 subfrontal, and 1 midline ACF floor. Commonest presenting symptom was visual change. Mean volume of tumor was 25.69 cm(3), with a size area of 7.28 cm(2). Five were revision cases. None had previous endonasal surgery. Average operating times decreased over time. Gross total removal was achieved in 14, with no deaths. Four patients had postoperative cerebrospinal fluid (CSF) leak. Rate of CSF leak decreased over time. Sixty percent of patients reported visual improvement. Two patients had radiological evidence of recurrence. CONCLUSION: ACF meningiomas can be safely removed endonasally, offering significant advantages over the traditional transcranial approach for suitable tumors. Early audit of this approach shows results achieved by this unit are comparable with the published literature.

Malignant cerebellar ganglioglioma.

We present a 62-year-old man with a high-grade cerebellar ganglioglioma with ataxia. Gangliogliomas are rare tumours which usually occur in the first 3 decades of life. There have only been a small number of grade IV gangliogliomas reported in the literature.