World Neurosurg
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Variations in cage design, material, and graft shape can affect osteointegration and adjacent segment range of motion (ROM) and stress after anterior cervical discectomy and fusion (ACDF) surgery. This study aimed to evaluate the biomechanical properties of a novel dynamic cervical cage design in both titanium (Ti) and polyether ether ketone (PEEK) with variations in bone graft shape using a single level ACDF (FE) model. ⋯ Both Ti and PEEK cages showed decreased ROM at the fusion and adjacent levels for all shapes of bone graft when compared with the intact spine model. In the Ti and PEEK dynamic cages, the elliptical shape bone graft showed decreased stress on the cage and increased stress on the bone graft. Further experimental and clinical studies are needed to confirm these encouraging biomechanical results of this novel dynamic, zero-profile fusion device with elliptical bone graft in ACDF surgery.
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Case Reports
Transcondylar Fossa Approach for Resection of Anterolateral Foramen Magnum Meningioma: 2D Operative Video.
Among the posterolateral corridors to the ventral foramen magnum (FM), the transcondylar fossa (supracondylar transjugular tubercle) approach (TCFA) is indicated for lesions lying anteriorly to the dentate ligament and above the jugular foramen and hypoglossal canal.1-13 It involves the drilling of the condylar fossa, namely the exocranial surface of the jugular tubercle. Despite the anatomic variability of the condyle and posterior condylar emissary vein,14,15 they are important landmarks for the TCFA. The extradural jugular tuberculectomy has no risk of iatrogenic mechanical instability compared with the transcondylar approach. ⋯ Postoperative magnetic resonance imaging confirmed complete resection of the tumor, and the patient was discharged neurologically intact on the third postoperative day. TCFA is a valuable technical option for selected anterolateral FM meningiomas. The perfect knowledge and intraoperative use of specific anatomic landmarks are critical to safely perform the TCFA while maximizing the exposure of the surgical target and decreasing the risk of postoperative mechanical instability of the craniovertebral junction.
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Case Reports
Subtemporal-Transtentorial Approach for Microsurgical Resection of Hemorrhagic Ambient Cistern AVM.
Arteriovenous malformations (AVMs) of the ambient cistern are an extremely rare and complex subgroup of vascular malformation, representing a clinical challenge due to the deep-seated, highly eloquent anatomic location and the debilitating, life-threatening consequences related to hemorrhagic presentation and surgical morbidity. Ultimately, a tailored treatment, based on the presenting symptoms, AVM angioarchitecture, and annual risk of hemorrhage should be discussed among a multidisciplinary team to find the best individualized strategy balancing between the pros and cons of each approach. In Video 1, we present the case of a 60-year-old man with a hemorrhaged AVM of the right ambient cistern, present the pros and cons of each possible treatment strategy, and illustrate the successful resection of this lesion through a subtemporal-transtentorial microsurgical approach.
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Case Reports
An Easy Adjustable Sling Technique of Ectatic Vertebral Artery Transposition for Microvascular Decompression.
Hemifacial spasm caused by an elongated, tortuous, or enlarged vertebral artery (VA) can be difficult to treat. Greater rates of incomplete cure also have been noted.1-6 In this video, we demonstrate the key steps of a simple and effective adjustable sling technique of an ectatic VA transposition for microvascular decompression. In this patient, an ectatic VA was stacked on the posterior inferior cerebellar artery, and together they compressed the root exit zone (REZ) of the facial nerve. ⋯ We made a small dural incision at the anchor point, where an aneurysm clip was applied to hold the sling securely under tension but not to cause kinking of the VA/posterior inferior cerebellar artery. The patient had no hemifacial spasm immediately after the operation and thereafter. This adjustable sling technique provides an easy and strong hold to maintain an ectatic VA away from the REZ of the facial nerve (Video 1).
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Pelvic fixation is becoming an increasingly important caudal anchor point for long lumbar constructs, high-grade spondylolisthesis, fixation of sacral fractures, and support for 3-column osteotomies, by adding lumbosacral fixation anterior to the McCord pivot point. Iliac bolts were once common but have become less favorable due to screw head irritation and complications associated with connecting rods. S2-alar-iliac (S2AI) screws have been shown to achieve equivalent anchoring strength of constructs to the pelvis, while being lower profile and in line with the lumbar instrumentation. ⋯ Video 1 shows the placement of an S2AI screw and triangular titanium implant for pelvic fixation. The patient is a 68-year-old woman who presented with flat back syndrome, spinal stenosis, degenerative spondylolisthesis, pseudarthrosis of previously instrumented levels, and bilateral sacroiliitis. She underwent posterior instrumentation and fusion of L1 to S1 with pelvic fixation, open bilateral sacroiliac joint fusion, and multilevel Smith-Peterson osteotomies and transforaminal lumbar interbody fusions.