Morphologic Variations in the Circle of Willis as a Risk Factor for Aneurysm Rupture in the Anterior and Posterior Communicating Arteries.

BACKGROUND: Intracranial aneurysms are acquired abnormal vascular dilations. The most dangerous complication of a cerebral aneurysm is its rupture, with a high rate of mortality. This study aimed to determine whether there is an association between anatomic variations in the circle of Willis and ruptured aneurysms in the anterior and posterior communicating arteries. METHODS: A cross-sectional study of adult patients with a diagnosis of intracranial aneurysm was carried out between March 2015 and March 2019. The patients were divided into groups of ruptured or unruptured aneurysm in the anterior and posterior communicating arteries. RESULTS: A total of 132 patients with anterior and posterior communicating artery aneurysms were included. The presence of anatomic variation in the circle of Willis presented a statistically significant association with ruptured aneurysms (odds ratio [OR], 2.28; 95% confidence interval [CI], 1.11-4.65; P = 0.024). There was a statistically significant difference between the presence of nonspherical aneurysm and rupture (OR, 6.9; 95% CI, 3.12-15.48; P < 0.0001). Multivariate logistic regression observed smoking (OR, 2.4; 95% CI, 1.01-5.9; P = 0.4), anterior complex variations (OR, 2.68; 95% CI, 1.01-7.18; P < 0.04), and nonspherical morphology (OR, 4.7; 95% CI, 1.93-11.45; P = 0.001) presented a statistically significant association with the rupture. CONCLUSIONS: Our results suggest that the studied variations of the circle of Willis and nonspherical morphology, in addition to playing a role in the development of cerebral aneurysms, may contribute to their rupture.

Endoscopic Endonasal Resection of Schwannoma of Pterygopalatine Fossa.

Trigeminal schwannomas are benign slow-growing tumors originating from the peripheral nerve sheath. They account for 0.1%-0.4% of all intracranial tumors and 1%-8% of all intracranial schwannomas.1-3 While most of these tumors develop in the trigeminal ganglion within the middle fossa, trigeminal schwannomas can develop anywhere along the course of the trigeminal nerve. As a result, they can be intradural, interdural, and extradural.4,5 Trigeminal schwannomas from the pterygopalatine fossa (PPF) are extremely rare and very difficult to remove because of limited access to this region and the rich neurovascular contents. Numerous traditional microsurgical approaches to the PPF have been described; however, they are more invasive with increased morbidity.6,7 Therefore, endoscopic endonasal surgery is a feasible solution. This technique allows good visualization of the region with decreased morbidity and a shorter recovery period. A previously healthy, 40-year-old woman presented with right facial pain for 3 weeks. On neurologic examination, the patient had hypoesthesia in the territory of the maxillary (V2) branch of the right trigeminal nerve. She had no other symptoms on physical examination. Cranial computed tomography and magnetic resonance imaging were performed and showed a high signal density mass in the right PPF that exhibited heterogeneous contrast enhancement. She was initially treated with low-dose carbamazepine; however, the dose could not be further increased because of drowsiness and dizziness. Given the size and location of the mass, an endoscopic endonasal approach was performed, and the tumor was successfully resected (Video 1). The postoperative course was uneventful, and the patient had significant improvement of her symptoms and was discharged with no new neurologic deficits. However, she continued to have hypoesthesia of the V2 segment of the trigeminal nerve.

The Enigma of Orbital Compartment Syndrome After Lumbar Spine Surgery in the Prone Position: Case Report and Literature Review.

BACKGROUND: Perioperative visual loss after spinal surgery is a devastating complication for the patient and the surgical team. Two known major causes are ischemic optic neuropathy and central retinal artery occlusion (CRAO). Traditional understanding of CRAO has been consistently related to occurrence of periocular trauma and signs of increased intraorbital pressure in addition to visual loss. However, such orbital signs are not a feature of any common perioperative visual loss syndrome. CASE DESCRIPTION: A 55-year-old woman underwent prolonged lumbar decompression and fusion for spinal stenosis under general anesthesia in the prone position. At the end of surgery, periocular hyperemia, corneal edema, and a tense orbit on the right side were noted. Complete internal and external ophthalmoplegia was observed on examination. Orbital computed tomography confirmed the clinical diagnosis of orbital compartment syndrome. Bony decompression was performed, but the treated eye remained blind. Resolution of the complete ophthalmoplegia was observed during late follow-up. CONCLUSIONS: In retrospect, patients diagnosed with often misunderstood CRAO and ischemic optic neuropathy with orbital signs after spinal surgery most likely had orbital compartment syndrome. The inclusion of orbital signs in the clinical picture of ischemic optic neuropathy and CRAO is not only incorrect but also gives the impression of therapeutic futility, thereby preventing successful orbital decompression in a timely fashion.