Journal of neurosurgery. Spine
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Implanted intrathecal drug delivery systems may malfunction as a result of fracture of the intrathecal catheter. A suspected catheter fracture not seen on plain radiographs of the catheter system will typically prompt a contrast-enhanced imaging study of the pump. Injection of iodinated contrast medium into the pump system with routine fluoroscopy can sometimes fail to reveal subtle leaks. ⋯ The leak was visible on source images and was especially obvious after 3D reconstruction. This led to surgical revision of the catheter and subsequent resumption of normal pump function. The authors therefore suggest that if a leak is suspected in an implanted intrathecal catheter and routine contrast fluoroscopy is unrevealing, post-injection 3D-CT scanning should be performed to further investigate the possibility of a subtle leak.
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The authors report on an 81-year-old woman whose condition deteriorated 2 months after undergoing osteoplastic laminoplasty with placement of hydroxyapatite spacers. Magnetic resonance imaging showed postlaminectomy scar formation compressing the cervical spinal cord. ⋯ Histological diagnosis of the scar was fibrous granulation tissue with foreign body granuloma, characterized by multinucleated giant cells and marked increases of capillary vessels, fibroblasts, and collagen fibers. This case of symptomatic postlaminectomy scar formation after osteoplastic laminoplasty suggests that osteoplastic laminoplasty cannot always prevent laminectomy membrane formation.
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Comparative Study
Biomechanical comparison of lumbar total disc arthroplasty, discectomy, and fusion: effect on adjacent-level disc pressure and facet joint force.
With the increasing advocacy for total disc replacement (TDR) as a potential alternative to fusion in the management of lumbar degenerative disc disease, intradiscal pressures (IDPs) and facet joint stresses at the adjacent levels of spine have generated considerable interest. The purpose of this study was to compare adjacent-level IDPs and facet joint stresses among TDR, discectomy, and fusion. ⋯ Lumbar TDR maintained adjacent-level IDPs and facet force pressures near the values for intact spines, whereas adjacent-level IDPs tended to increase after discectomy or fusion and facet forces tended to increase after fusion.
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Several studies have characterized the relationship among postoperative thoracic, lumbar, and pelvic alignment in the sagittal plane. However, little is known of the relationship between postoperative thoracic kyphosis and sagittal cervical alignment in patients with adolescent idiopathic scoliosis (AIS) treated with all pedicle screw constructs. The authors examined this relationship and associated factors. ⋯ The sagittal profile of the thoracic spine is related to that of the cervical spine. The surgical treatment of Lenke Type 1 and 2 curves by using all pedicle screw constructs has a significant hypokyphotic effect on thoracic sagittal plane alignment (19 [86%] of 22 patients). If postoperative thoracic kyphosis is excessively decreased (mean 25.6°, p < 0.05), the cervical spine may decompensate into significant kyphosis.
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The aim of this study was to retrospectively evaluate the reliability and accuracy of cervical pedicle screw (CPS) placement using an intraoperative, full-rotation, 3D image (O-arm)-based navigation system and to assess the advantages and disadvantages of the system. ⋯ The O-arm offers high-resolution 2D or 3D images, facilitates accurate and safe CPS insertion with high-quality navigation, and provides other substantial benefits for cervical spinal instrumentation. Even with current optimized technology, however, CPS perforation cannot be completely prevented, with 8.3% instances of minor violations, which do not cause significant complications, and 2.8% instances of major pedicle violations, which may cause catastrophic complications. Therefore, a combination of intraoperative 3D image-based navigation with other techniques may result in more accurate CPS placement.