SUMMARY:Two decades following their description, the significance of Modic vertebral endplate and marrow changes remains a matter of debate. These changes are closely related to the normal degenerative process affecting the lumbar spine, and their prevalence increases with age. However, the exact pathogenesis underlying these changes and their relation to segmental instability of the lumbar spine and to low back pain remain unclear. In this paper, we review the literature relevant to this topic and discuss the currently available evidence regarding the pathologic and clinical significance of Modic changes. Degenerative vertebral endplate and subchondral bone marrow changes were first noted on MR imaging by de Roos et al in 1987.1 A formal classification was subsequently provided by 2 based on a study of 474 patients, most of whom had chronic low back pain (LBP). These authors described 2 types of endplate and marrow changes:Type 1 changes (Fig 1) were hypointense on T1-weighted imaging (T1WI) and hyperintense on T2-weighted imaging (T2WI) and were shown to represent bone marrow edema and inflammation.Type 2 changes (Fig 2) were hyperintense on T1WI and isointense or slightly hyperintense on T2WI and were associated with conversion of normal red hemopoietic bone marrow into yellow fatty marrow as a result of marrow ischemia.

Despite high rates of physical disability and depression, the vast majority of patients are satisfied with life and do not regret having undergone surgery.

mortality. The purpose of this paper is to review the biomechanical aspects, clinical features, radiologic criteria, and treatment strategies of AOD. Given that the diagnosis of AOD can be very challenging, a high degree of clinical suspicion is essential to ensure timely recognition and treatment, thus preventing neurological decline or death. Core tip: Atlanto-occipital dislocation (AOD) is being increasingly recognized as a potentially survivable injury as a result of improved prehospital management, increased awareness, and more aggressive management. However, despite overall improved outcomes, AOD is still associated with significant morbidity and mortality. Given that the diagnosis can be very challenging, a high degree of clinical suspicion is essential to ensure timely recognition and treatment, thus preventing neurological decline or death.Hall GC, Kinsman MJ, Nazar RG, Hruska RT, Mansfield KJ, Boakye M, Rahme R. Atlanto-occipital dislocation. INTRODUCTIONIn a recent study of 300 patients with cervical spine trauma, 30% of injuries were located between the occiput and C2. Among these, acute spondylolysis of C2 (hangman's fracture), C1 ring fractures, odontoid fractures, and atlanto-occipital dislocation (AOD) were the most common [1] . Graham AbstractAtlanto-occipital dislocation (AOD) is being increasingly recognized as a potentially survivable injury as a result of improved prehospital management of polytrauma patients and increased awareness of this entity, leading to earlier diagnosis and more aggressive treatment. However, despite overall improved outcomes, AOD is still associated with significant morbidity and MINIREVIEWS 236March 18, 2015|Volume 6|Issue 2|

BACKGROUND During its development and preclinical assessment, a novel, 3-dimensional (3D), high-definition (4K-HD) exoscope system was formerly shown to provide an immersive surgical experience, while maintaining a portable, low-profile design. OBJECTIVE To assess the clinical applicability of this 3D 4K-HD exoscope via first-in-man surgical use. METHODS The operative workflow, functionality, and visual haptics of the 3D 4K-HD exoscope were assessed in a variety of microneurosurgical cases at 2 US centers. RESULTS Nineteen microneurosurgical procedures in 18 patients were performed exclusively using the 3D 4K-HD exoscope. Pathologies treated included 4 aneurysms, 3 cavernous malformations (1 with intraoperative electrocorticography), 2 arteriovenous malformations, 1 foramen magnum meningioma, 1 convexity meningioma, 1 glioma, 1 occipital cyst, 1 chiari malformation, 1 carotid endarterectomy, 1 subdural hematoma, 1 anterior cervical discectomy and fusion, and 2 lumbar laminectomies. All patients experienced good surgical and clinical outcomes. Similar to preclinical assessments, the 3D 4K-HD exoscope provided an immersive 3D surgical experience for the primary surgeon, assistants, and trainees. The small exoscope frame, large depth of field, and hand/foot pedal controls improved exoscope mobility, decreased need to re-focus, and provided unobstructed operative corridors. Flexible positioning of the camera allows the surgeon's posture to be kept in a neutral position with uncompromised viewing angles. CONCLUSION The first-in-man clinical experience with the 3D 4K-HD exoscope confirms its excellent optics and ergonomics for the entire operative team, with high workflow adaptability for a variety of microneurosurgical cases. Expanded clinical use of the 3D 4K-HD exoscope is justified.

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BACKGROUND Cerebral bypass operation is a technically challenging operation that requires excellent surgical visibility and efficient ergonomics to minimize complications and maximize successful revascularization. Despite the operative microscope's utilization for the past two generations, there remains a need for continued improvement in operative visualization and surgical ergonomics. OBJECTIVE To report the positives and negatives of our initial experience using a novel 4 K high-definition (4K-HD) 3-dimensional (3D) exoscope (EX) for cranial bypass surgery. METHODS A retrospective review over 6 mo was performed of all patients who have undergone cerebral bypass surgery at a single institution using the 4K-HD 3D EX. Advantages and disadvantages of the EX and clinical outcome of the patients were assessed. RESULTS A total of 5 patients underwent cerebral EC-IC bypass surgery with no EX-related complications and successful revascularization. The lightweight design of the EX allowed for easy instrument maneuverability as well as uncomplicated surgical set up in the operating room. The assistance of the cosurgeon was significantly more efficient compared to that of the operating microscope. The large monitor allowed for an immersive, collaborative, and valuable educational surgical experience. CONCLUSION Using the EX for cerebral bypass surgery, with 3D ultra-high-definition optics, enhancements of ergonomics, and improved training, we believe that the 3D 4K-HD EX may represent the next generation of operative scopes in microneurosurgery.

Background and Purpose The role of endovascular therapy for acute M2 trunk occlusions is debatable. Through a subgroup analysis of PROACT-II, we compared outcomes of M2 occlusions in treatment and control arms. Methods Solitary M2 occlusions were identified from the PROACT-II database. Primary endpoints were successful angiographic reperfusion (TICI 2-3) at 120 minutes and functional independence (mRS 0-2) at 90 days. Results Forty-four patients with solitary M2 occlusions, 30 in the treatment arm and 14 in the control arm, were identified. Successful reperfusion (TICI 2-3) was achieved in 53.6% and 16.7% of patients in the treatment and control arms, respectively (p=0.04). A favorable clinical outcome (mRS 0-2) was observed in 53.3% and 28.6%, respectively (p=0.19). Baseline characteristics were similar between the 2 groups. Conclusions Intra-arterial thrombolysis may lead to a 3-fold increase in the rate of early reperfusion of solitary M2 occlusions and could potentially double the chance of a favorable functional outcome at 90 days.

Meningeal melanocytoma is a rare benign CNS tumor derived from the leptomeningeal melanocytes. Although unusual, malignant transformation with leptomeningeal seeding into the brain or spinal cord may occur years after the initial diagnosis. The authors report a unique case of multifocal benign meningeal melanocytoma involving both cerebellopontine angles and the thoracic spinal cord, with associated diffuse leptomeningeal hyperpigmentation. They review the literature relevant to this topic and discuss the radiological and pathological features of this disease as well as its treatment options.