World Neurosurg
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How Chiari malformation type I (CM-I) affects posterior fossa brain structures and produces various symptoms remains unclear. The fourth ventricle is surrounded by critical structures required for normal function. The foramen of Magendie can be obstructed in CM-I; therefore, fourth ventricle changes may occur. To test this hypothesis, we assessed fourth ventricle volume in CM-I compared with healthy controls. ⋯ The fourth ventricle can be enlarged in CM-I independent of lateral ventricle size and is associated with greater tonsillar descent. Most importantly, fourth ventricle enlargement was associated with a worse clinical and radiographic presentation independent of PFV. Fourth ventricle enlargement can affect critical structures and may be a mechanism contributing to symptoms unexplained by tonsil descent. Fourth ventricle enlargement is a useful adjunct in assessing CM-I.
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Cerebrospinal fluid (CSF) drainage reduces the risk of paraplegia in thoracoabdominal aortic aneurysm (TAAA) repair. Intracranial hemorrhage after TAAA repair has been reported as a rare complication of CSF drainage; however, spinal subarachnoid hematoma has never been reported. Here, we present a case of lumbosacral subarachnoid hematoma after CSF drainage in TAAA repair. ⋯ We present a rare case of lumbosacral subarachnoid hematoma after CSF drainage in TAAA repair. We should consider spinal subarachnoid hematoma when paralysis in the lower limbs occurs after CSF drainage.
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Compensatory mechanisms for cervical kyphosis are unclear. Few alignment analyses have targeted ongoing cervical kyphosis and detailed the effects of compensatory alignment changes. ⋯ When CL decreased after ACCF, ΔO-C2 immediately compensated for the CL loss that could lead to failure to obtain horizontal gaze. If cSVA increased, Δcaudal adjacent angle and ΔT1 slope (extension below the kyphosis) compensated for the horizontal offset translation. The noncompensatory status (ΔcSVA and ΔT1 positive) may necessitate further correction surgery in which the caudal fused level is beyond T1.
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Ehlers-Danlos syndrome (EDS) is a group of rare congenital disorders of connective tissue that result in tissue fragility and joint hyperextensibility. Owing to its rarity, outcomes of pediatric spine surgery in patients with EDS are poorly characterized. Although it has been suggested that complication rates are high, few studies have characterized these complications. ⋯ Pediatric patients with EDS do not appear to be at a higher risk of bleeding or other complications during spine surgery as reported in past case series. This is the largest retrospective review of its kind that has been performed in this patient population.
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The center of rotation (COR), instantaneous center of rotation (ICR), instantaneous axis of rotation, instantaneous helical axis, finite helical axis, and helical axis of motion are important kinematic parameters for evaluating the quality of intervertebral motion of the cervical spine (QIMC). These parameters embody different concepts and are calculated using various methods. In this review, the distinctions and connections between these kinematic parameters are analyzed according to the concepts, research, and measurement techniques to provide a theoretic basis for future research and new research directions. ⋯ COR was the simplest but not the most accurate parameter to evaluate the QIMC. Conversely, instantaneous helical axis/helical axis of motion were the most accurate, but relatively complex parameters to evaluate the QIMC. ICR showed dynamic changes during flexion-extension motion, but not the three-dimensional kinematic motion of the cervical spine. These parameters were equivalent only in certain situations but cannot be substituted for each other in the clinic. A dynamic radiographic in vivo study was the most convenient and frequently used research method to calculate COR, but failed to describe the dynamic movement. The method of perpendicular bisectors was widely used to calculate the COR or ICR. Therefore, a combination of new research and calculation methods to simply and effectively evaluate the QIMC requires further investigation.