Anterior cervical spine fusion: struts,plugs, and plates

Bone grafting in the cervical spine is an expanding and rapidly changing area. Its success depends on the presence of bone formation, bone incorporation, and ongoing adaptive remodeling to mechanical loads. The evaluation of anterior cervical spine grafts requires a basic understanding of bone graft physiology, its clinical applications, and its postoperative appearances. The roles of routine radiography, polydirectional tomography, computed tomography, and magnetic resonance imaging in the assessment and follow-up of the postoperatively grafted cervical spine will be discussed. The main focus of this paper is to review current surgical procedures utilized for stabilizing the cervical spine as well as to discuss the radiologist's role in the imaging of this region.     

Plain radiograph assessment of spinal hardware

The frequency and variety of spinal instrumentation has increased tremendously over the past 100 years, and imaging plays an important role in evaluating the postoperative spine. Although assessment of spinal hardware often involves a multimodality approach, plain radiographs are the most commonly used modality, given accessibility, cost, relatively low radiation dose compared with computed tomography, and provision of positional information. An approach to assessment of plain radiographs of the postoperative spine is discussed, and examples of common postoperative complications are provided, including infection, hardware failure, incomplete fusion, and junctional failure.     

Imaging the postoperative spine

Imaging assessment of the postoperative spine is complex and depends on many factors. Postoperative imaging studies evaluate the position of implants, adequacy of decompression, fusion status, and potential complications. This article provides a review of various imaging techniques, with their advantages and disadvantages, for the evaluation of the postoperative spine. It also gives an overview of normal and abnormal postoperative appearances of the spine as seen via various modalities, with an emphasis on postoperative complications.     

Lumbar intervertebral instability: a review

Intervertebral instability of the lumbar spine is thought to be a possible pathomechanical mechanism underlying low back pain and sciatica and is often an important factor in determining surgical indication for spinal fusion and decompression. Instability of the lumbar spine, however, remains a controversial and poorly understood topic. At present, much controversy exists regarding the proper definition of the condition, the best diagnostic methods, and the most efficacious treatment approaches. Clinical presentation is not specific, and the relationship between radiologic evidence of instability and its symptoms is controversial. Because of its simplicity, low expense, and pervasive availability, functional flexion-extension radiography is the most thoroughly studied and the most widely used method in the imaging diagnosis of lumbar intervertebral instability. In this article, we provide an overview of the current concepts of vertebral instability, focusing on degenerative lumbar intervertebral instability, and review the different imaging modalities most indicated in diagnosing vertebral instability.     

PET/CT in oncology--a major advance

The concept of hardware fusion between positron emission tomography (PET) and computed tomography (CT) has only been introduced commercially in the last 4 years. The advantages of this combined technique over PET alone have become obvious. There is increasing evidence to suggest that PET/CT adds complementary information in staging, re-staging and follow-up in oncology patients, leading to changes in management plans. The present paper is a review of the strengths, weaknesses, current evidence and future directions of this technique.     

Dual cervical thoracic coil for spine magnetic resonance imaging

The need for repositioning of surface coils and patients in MR examinations of the cervical and thoracic spine prolongs examination time. A new receiver design is proposed which overcomes this problem. The device is composed of two actively decoupled receiver coils mounted on the frame of a Philadelphia collar. These coils may be used separately to image either the thoracic or cervical spine or together to produce larger field-of-view images of the combined region. Signal-to-noise ratios of the separate cervical and thoracic spine images are not degraded as a result of mounting the receivers together. The full cervical and thoracic region is shown to be imaged at a signal-to-noise ratio significantly higher than that afforded by the body coil. A retrospective review of our case load suggests that a time saving could be achieved in approximately 1/3 of spine examinations by using this coil.     

Epiphyseal fusion assessment based on wavelets decomposition analysis

Epiphyseal fusion is a finding frequently analysed in hand wrist radiographs. It is tested in the bone age assessment, the gonadal dysgenesis, etc. The computerized fusion analysis is performed on an automatically selected region of interest containing the lower edge of epiphysis and the upper edge of metaphysis. In the analysis a wavelets decomposition approach is employed. The wavelets decomposition components are first subjected to a preliminary test which rejects the overexposed images whose analysis would not give reasonable results. This increases the accuracy of the algorithm and a chance for an unsupervised application. Then, a quantitative measure is found. Its value decreases while the epiphyseal fusion proceeds. The analysis yields an assignment of fusion to one of four stages; no fusion, early stage of fusion, advanced stage of fusion, and fusion completed. The results show that wavelets decomposition components may efficiently be applied to a texture analysis.     

Spinal fusion-hardware construct: Basic concepts and imaging review

The interpretation of spinal images fixed with metallic hardware forms an increasing bulk of daily practice in a busy imaging department. Radiologists are required to be familiar with the instrumentation and operative options used in spinal fixation and fusion procedures, especially in his or her institute. This is critical in evaluating the position of implants and potential complications associated with the operative approaches and spinal fixation devices used. Thus, the radiologist can play an important role in patient care and outcome. This review outlines the advantages and disadvantages of commonly used imaging methods and reports on the best yield for each modality and how to overcome the problematic issues associated with the presence of metallic hardware during imaging. Baseline radiographs are essential as they are the baseline point for evaluation of future studies should patients develop symptoms suggesting possible complications. They may justify further imaging workup with computed tomography, magnetic resonance and/or nuclear medicine studies as the evaluation of a patient with a spinal implant involves a multi-modality approach. This review describes imaging features of potential complications associated with spinal fusion surgery as well as the instrumentation used. This basic knowledge aims to help radiologists approach everyday practice in clinical imaging.     

Assessment of the spine with CT and MRI prior to interspinous/interlaminar spinal procedures: a pictorial review

Imaging of the spine is increasingly available, whether as dedicated spine examinations or as studies that include the spine in the images obtained (e.g. CT abdomen). This pictorial review discusses imaging of the spine with CT and MRI and how prior review of this imaging can be helpful with potentially difficult spinal procedures. Pathologies illustrated include osteoarthritis, scoliosis, inflammatory spondyloarthropathies and post-operative spines.Many spinal procedures are performed using the interspinous (midline) or interlaminar (paramedian) approach with high success rates. These procedures include myelograms for diagnosis, epidural corticosteroid injections for pain relief, central neuraxial blocks in regional anaesthesia and lumbar punctures for cerebrospinal fluid (CSF) analysis. The causes for difficult spinal procedures are wide in range and include pathological/anatomical conditions of the spine. As with all imaging as a whole, spinal imaging is increasingly more available with each individual patient [1], and review of such imaging can be helpful for difficult procedures.This pictorial review will discuss imaging (CT, MRI) of spinal conditions that can contribute to difficult spinal procedures, in particular osteoarthritis, scoliosis and the inflammatory spondyloarthropathies. The illustrations will focus on the interspinous/interlaminar approach for the thoracolumbar spine, but the principles provided can be used for other approaches.     

胶原支架负载BMP-2促进大鼠脊柱横突融合的临床观察

目的探讨胶原支架负载骨形成蛋白2（BMP2）在脊柱横突融合中的应用价值。方法将60只雄性SD大鼠随机分成3组,假手术组、材料组与复合材料组,各20只,行脊柱后外侧横突间融合手术,材料组和复合材料组大鼠L4～5横突间分别植入胶原支架和胶原支架负载BMP2,未植入任何材料组为假手术组。术后8周予手触力学评定、X线评分、mi-cro-CT扫描、H＆E染色观察等分析和检测。结果手触力学评定、X线评分、micro-CT扫描、H＆E染色观察显示8周后材料组和复合材料组大鼠L4～5横突间均有不同程度融合,假手术未见融合,且复合材料组融合效果优于单纯材料组。结论胶原材料负载BMP2促进大鼠脊柱横突融合,具有潜在的临床应用价值。     

Paget's disease of the spine: unusual features and complications

Paget's disease of bone is a common disorder, with the spine being involved in over 50% of cases. This pictorial review illustrates unusual features and complications of the disease as related to the spine. Unusual features include location in the atlanto-axial region, lytic vertebral Paget's disease and Pagetic ankylosis. Complications related to the spine are mainly neurological due to spinal stenosis, compression fractures and sarcomatous degeneration     

MR spectrum in spinal dysraphism

Spinal dysraphism is a general term which encompasses a wide variety of anomalies of the spine, all of which result from imperfect midline fusion of the embryonic neural tube. This term refers to large defects that involve the spine and not to small vertical clefts commonly seen within the spinal process of L5 or S1. We present a spectrum of MR imaging findings selected from a retrospective review of 100 patients of spinal dysraphism evaluated at our institution. Received: 18 May 2000 Revised: 13 July 2000 Accepted: 13 July 2000     

Sensory-motor control of the lower back: implications for rehabilitation.

Although low back pain (LBP) is a widespread and disabling health problem, there is a lack of evidence based medicine with respect to its treatment and rehabilitation. A major reason for this is the poor understanding of the underlying mechanisms of the LBP syndromes. In an attempt to fill this gap, the present review article provides an overview of the sensory-motor control aspects of trunk stabilization and postural control of the trunk, and how they may relate to the evolution of LBP. In particular, the anatomy and physiology of the sensory-motor control mechanisms of the trunk muscles that contribute to general and segmental stability of the lumbar spine will be elucidated. Furthermore, a brief overview of current theories of postural control will be provided with respect to spinal stabilization. Finally, a concept of the pathophysiological changes within the sensory-motor control mechanisms of the lumbar spine in the presence of muscle injury and pain will be presented. The impact of pain and muscle injury on the muscular support for the lumbar motion segment will be discussed along with the deficits in neuromuscular control in LBP patients with decreased segmental lumbar stability.     

上颈椎创伤诊治:重要理念回顾与常见误区分析

上颈椎指颅颈交界区域,包括3个椎节(枕骨髁、寰椎和枢椎)与2个椎间关节,由于贡献了近一半的颈椎活动度,上颈椎易于损伤。上颈椎解剖结构复杂,功能重要,具有特殊的运动学特征,导致其创伤的诊治具有挑战性。基于文献及作者的临床实践,本文旨在为读者回顾上颈椎创伤诊治过程中的关键点,并分析常见的失误。笔者建议在整个诊治过程中,应该重点关注骨折愈合的可能性,以及椎间关节功能(稳定与节段间运动)恢复的可能性。     

Cervical spine evaluation in pediatric trauma

OBJECTIVE: This article will review the current literature as it relates to imaging of the child suspected to have cervical spine injury (CSI) and the imaging findings of pediatric CSI, focusing on strategies to minimize radiation dose while maximizing diagnostic yield. CONCLUSION: Although CSI is uncommon in children, the clinical implications of failure to correctly diagnose CSI are significant. Clinical decision rules proven effective in predicting CSI in adults cannot be uniformly applied to children.     

History of computer-assisted orthopedic surgery (CAOS) in sports medicine

Computer-assisted orthopedic surgery and navigation applications have a history rooted in the desire to link imaging technology with real-time anatomic landmarks. Although applications are still evolving in the clinical and research setting, computer-assisted orthopedic surgery has already demonstrated in certain procedures its potential for improving the surgeon's accuracy, reproducibility (once past the learning curve), and in reducing outlier outcomes. It is also being used as an educational tool to assist less experienced surgeons in interpreting measurements and precision placements related to well defined anatomic landmarks. It also can assist experienced surgeons, in real-time, plan their bony cuts, tunnel placement, and with ligament balancing. Presently, the additional time, the expense to acquire the needed software and hardware, and restricted reimbursement have slowed the widespread use of navigation. Its current applications have been primarily in joint replacement surgery, spine surgery, and trauma. It has not been widely used in the clinical setting for sports medicine procedures. Sports medicine applications such as individualizing tunnel placement in ligament surgery, opening wedge osteotomy with and without accompanying ligament reconstruction, and balancing and tensioning of the ligaments during the procedure (allowing real-time corrections if necessary) are currently being evaluated and being used on a limited clinical basis.     

Low-dose helical computed tomography (CT) in the perioperative workup of adolescent idiopathic scoliosis

The study aims were to estimate the radiation dose in patients examined with low dose spine CT and to compare it with that received by patients undergoing standard CT for trauma of the same region, as well as to evaluate the impact of dose reduction on image quality. Radiation doses in 113 consecutive low dose spine CTs were compared with those in 127 CTs for trauma. The inter- and intraobserver agreement in measurements of pedicular width, and vertebral rotation, measurements of signal-to-noise ratio and assessment of hardware status were the indicators in the evaluation of image quality. The effective dose of the low dose spine CT (0.37 mSv) was 20 times lower than that of a standard CT for trauma (13.09 mSv). This dose reduction conveyed no impact on image quality. This low dose spine CT protocol allows detailed evaluation that is necessary for preoperative planning and postoperative evaluation.     

Subluxation of the upper thoracic spine in rheumatoid arthritis

Only single cases with rheumatoid arthritis of the thoracic spine with vertebral subluxation have been reported to date. In a review of 100 patients with severe rheumatoid arthritis who had undergone occipitocervical fusion, arthritis of the upper thoracic spine with subluxation was discovered on conventional radiographs in four patients. Two additional patients were found elsewhere. Magnetic resonance imaging (MRI) was performed in three of the patients, confirming the diagnosis of subluxation of the upper thoracic vertebrae. In addition, MRI revealed encroachment on the anterior sub-arachnoid space and compression of the spinal cord.