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BACKGROUND: Balloon-assisted kyphoplasty (BAK) is a well-accepted treatment for symptomatic vertebral compression fractures (VCF) secondary to osteoporosis. Some have raised a concern of an increased incidence of adjacent fractures due to alterations in spine biomechanics after cement augmentation. The incidence of subsequent VCFs following BAK is poorly understood. The aim of this study was to investigate the timing, location, and incidence of new VCFs following BAK and to identify risk factors associated specifically with the occurrence of new adjacent level fractures. OBJECTIVES: The study was performed to determine the incidence of symptomatic subsequent adjacent and remote level compression fractures in a cohort of patients undergoing BAK. STUDY DESIGN: Longitudinal cohort investigation at an academic medical center and a central referral center for VCFs. SETTING: A consecutive single surgeon series of 726 patients with osteoporotic compression fractures. METHODS: A prospectively collected cohort of 726 patients who underwent BAK between 2001 and 2014 for osteoporotic VCFs was evaluated. Seventy-seven patients were identified who underwent a second BAK for a new compression fracture and were include in the present series. The indication for BAK treatment was pain unresponsive to non-surgical management for all cases. Variables were recorded for each patient, including the time between index and subsequent fracture, fracture level, and number of initial fractures as well as with tobacco use, body mass index (BMI), and chronic steroid use. RESULTS: Seventy-seven of 726 patients (10.6%) underwent a second BAK procedure on average 350 days following the initial procedure (range 21 to 2,691 days). Third and fourth procedures were less common, treated in 11 and 3 patients, respectively. Forty-eight of 77 patients (62%) suffered a fracture at a level immediately adjacent to the index level at mean time of 256 days. Remote level fractures were treated at a mean time of 489 days, but no statistical difference was noted. There was no statistically significant difference between tobacco use, BMI, and chronic steroid use between patients suffering from remote and adjacent level VCFs. LIMITATIONS: This was not a population based study, and the true incidence of subsequent fractures after BAK might be underestimated by this analysis. CONCLUSIONS: Symptomatic compression fractures after BAK are relatively uncommon and may occur long after the initial kyphoplasty procedure. Only half of subsequent fractures occur immediately adjacent to the initially treated level; the others occur remotely. Patients with a single symptomatic thoracic or lumbar fracture suffered from remote and adjacent level fractures equally. In contrast, all patients who suffered both a thoracic and lumbar fracture at the same time had a second fracture at an adjacent level. Specific risk factors for remote versus adjacent level fractures could not be determined. Key words: Balloon kyphoplasty, cement augmentation, osteoporosis, vertebral compression fracture, adjacent level fracture, vertebroplasty.

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BACKGROUND: Postoperative cognitive dysfunction (POCD) is a known complication after intracranial surgery. Impaired hippocampal neurogenesis has been associated with cognitive dysfunction in animal models. METHODS: In order to assess hippocampal changes after brain surgery, a frontal lobe corticectomy was performed in ten adult Wistar rats (group 4). Three different control groups (n = 10 each) included no treatment (G1), general anesthesia alone (G2), and craniectomy without dural opening (G3). Twenty-four hours after surgery, half of the animals were killed, and the mRNA levels for IL-6, TNF-α, and brain-derived growth factor (BDNF) in the contralateral hippocampus were assessed by qPCR. Seven days later, the remaining animals underwent anxiety and memory testing. Afterwards, the number of immature neurons in the hippocampal cortex was measured by doublecortin (DCX) staining. RESULTS: Twenty-four hours after surgery, mRNA levels of IL-6 and TNF-α increased and BDNF decreased in both surgical groups G3 and G4 (p = 0.012). Cognitive tests demonstrated an increase in anxiety levels and memory impairment in surgical groups compared with non-surgical animals. These changes correlated with an inhibition of hippocampal neurogenesis evidenced by a decreased number of new neurons (mean ± SD for G1-4: 66.4 ± 24; 57.6 ± 22.2; 21.3 ± 3.78; 5.7 ± 1.05, p < 0.001, non-parametric ANOVA). CONCLUSIONS: Intracranial surgery was demonstrated to induce an inflammatory reaction within the hippocampus that compromised neurogenesis and impaired normal cognitive processing. Corticectomy had a greater effect than craniotomy alone, indicating a central trigger for hippocampal inflammatory changes. POCD after craniotomy may originate from a central inflammatory response resulting from surgical trauma to the brain parenchyma.

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STUDY DESIGN: Reliability analysis based on expert panel case series review and grading per the Enneking and Weinstein-Boriani-Biagini classification systems. OBJECTIVE: To assess the reliability of the Enneking and Weinstein-Boriani-Biagini classification systems. SUMMARY OF BACKGROUND DATA: The Enneking and Weinstein-Boriani-Biagini (WBB) classifications were developed to stage and facilitate treatment planning in patients with primary spine tumors. To date, their interobserver and intraobserver reliability has not been assessed-a fundamental step in facilitating broader clinical and research use. METHODS: Clinical information, imaging studies, and biopsy results were compiled from 15 selected patients with primary spinal tumors. Eighteen spine surgeons independently estimated and scored the cases for Enneking grade, tumor and metastasis categories, Enneking stage, Enneking-recommended surgical margin, WBB zones and layers, and WBB-recommended surgical procedures, with a second assessment performed after random resorting of cases. Interobserver and intraobserver reliability of each category were assessed by percent agreement or proportional overlap. The Fleiss, Cohen, and Mezzich kappa statistics (kappa) were then applied, determined by the type of variable analyzed. RESULTS: The kappa statistics for interobserver reliability were 0.82, 0.22, 0.00, 0.57, 0.47, 0.31, 0.58, and 0.54 for the fields of Enneking grade, tumor and metastasis categories, Enneking stage, Enneking-recommended surgical margin, WBB zones and layers, and WBB-recommended surgical procedures, respectively. The kappa statistics for intraobserver reliability were 0.97, 0.53, 0.47, 0.82, 0.67, 0.63, 0.79, and 0.79 for the same respective fields. According to Landis and Koch, the ranges of kappa values of 0.00 to 0.20, 0.21 to 0.40, 0.41 to 0.60, 0.61 to 0.80, and >0.80 imply slight, fair, moderate, substantial, and near-perfect agreement, respectively. CONCLUSION: Results indicate moderate interobserver reliability and substantial and near-perfect intraobserver reliability for both the Enneking and WBB classification in terms of staging and guidance for treatment, despite a less than moderate interobserver reliability in interpreting the Enneking local tumor extension and WBB sector. Before incorporating the classifications in the clinical practice and research studies, further work is required to investigate the validity of the classifications.

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La radiocirugía en la columna vertebral representa una extensión lógica de la terapia de radiación actual al combinar altas dosis ajustadas con tecnología de guía por imagen. En la actualidad, la radiocirugía en la columna vertebral se considera una alternativa segura y efectiva a la cirugía abierta para diferentes tipos de tumores malignos y benignos. Los resultados se han fijado en mejorar la seguridad, los signos y síntomas de radiculopatía y mielopatía relacionados con la compresión de tumores, y aliviar el dolor. Los beneficios potenciales más importantes de la erradicación radioquirúrgica de lesiones dorsales suponen tratamientos más cortos, atención médica de consulta externa, recuperación breve y una buena respuesta clínica. Asimismo, la radiocirugía se puede utilizar como tratamiento primario de salvataje para pacientes con lesiones en las que no se recomiendan técnicas de cirugía abierta o como tratamiento adicional a ésta.

Spine radiosurgery represents a logical extension of the current state-of-the-art radiation therapy of combining highlyconformal dose delivery with image guidance technology. Spine radiosurgery is now considered to be a safe and effective alternative to open surgery for a variety of both benign and malignantspinal tumors. Outcomes have focused on improvement in pain scores, safety, and alleviating the signs and symptoms of radiculopathy and myelopathy related to tumor compression. The major potential benefits of radiosurgical ablation of spinal lesions are short treatment times, delivery in an outpatient setting, rapid recovery, and good clinical response. Radiosurgery may also be utilized as a primary treatment for some lesions, as a salvagetreatment for patients or lesions not amenable to open surgical techniques, or as an adjunct to open surgery.

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