Imaging of the postoperative spine

Spinal instrumentation techniques have expanded dramatically during the past several decades, but the search for the perfect operative approach and fixation system continues. Fixation devices are designed for the cervical, thoracic, lumbar, and sacral segments using anterior, posterior, transverse, videoarthroscopic, and combined approaches. In most cases, bone grafting also is performed, because instrument failure occurs if solid bony fusion is not achieved. Radiologists must understand the operative and instrumentation options. Knowledge of expected results, appearance of graft material, and different forms of instrumentation is critical for evaluating position of implants and potential complications associated with operative approaches and spinal fixation devices.     

New techniques in lumbar spinal instrumentation: what the radiologist needs to know

Lumbar spinal fusion is a commonly performed procedure, and, despite changes in cage types and fixation hardware, radiologists have, over the years, become familiar with the imaging features of typical spinal fusion and many of the complications seen in patients after surgery, including pseudoarthrosis, hardware loosening, and recurrent or residual disk herniation. Recently, however, novel approaches and devices have been developed, including advances in minimally invasive surgery, the increasing use of osteoinductive materials, and a wide variety of motion-preserving devices. These new approaches and devices manifest with characteristic imaging features and the potential for unusual and unexpected complications. Several of these devices and approaches are experimental, but many, including those devices used in lateral approaches to fusion, as well as the use of bone morphogenic protein, disk arthroplasty, and interspinous spacers, are seen with increasing frequency in daily clinical practice. Given the recent advances in spinal fusion surgery, it is important that radiologists have a basic understanding of the rationale behind these procedures, the common imaging features of the devices, and the complications associated with their use.     

Postoperatives Syndrom nach Wirbelsäuleneingriffen

Postoperative syndrome after spine surgery, i.e., symptoms or syndromes caused by complications or procedure-related consequences, is gaining more and more importance. Due to great improvements concerning imaging and operative techniques (microsurgery, instrumentation) the total number of spinal surgeries as well as their related complications are increasing. Procedure-related postoperative complications including neurological deficit syndromes can occur acutely or at a later date. Concerning imaging techniques for postoperative evaluation after spinal surgery there are several modalities available. Their indications depend on complex factors including initial pathology the surgery was performed for, kind of surgical technique (surgical approach, instrumentation), anatomy of the patient as well as the time between onset of symptoms and surgery. In cases of ambiguous findings, the combination of different imaging techniques can be instrumental.     

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 in adult scoliosis: preoperative assessment and postoperative complications

Adult scoliosis rates range from 2 to 32%. Surgery for scoliosis is common. Accurate and surgically relevant information should be provided to the referring surgeon from pre- and postoperative imaging. There are various methods to correct scoliosis surgically with the end points correction of the curve and relief of symptoms. This is achieved through the placement of spinal instrumentation with a goal of osseous fusion across the instrumented levels. There are many potential postoperative complications. The initial and postoperative imaging, types of surgery, and hardware are reviewed along with the common early and late complications with relevant illustrations.     

Value of polydirectional tomography in the assessment of the postoperative spine after anterior decompression and vertebral body autografting

With the growing number of orthopedic reconstructive spinal procedures, the use of bone grafting has steadily increased in the past decade. An understanding of the biology of bone grafting is essential for both the clinician and radiologist. Despite the advent of computed tomography and magnetic resonance imaging, conventional polydirectional tomography remains an important tool in the evaluation of vertebral body autografts. Trispiral or hypocycloidal tomography plays a valuable role in the assessment of bone graft fusion and possible complications, especially in the presence of metallic fixation devices. We present our imaging experience derived from 375 patients with cervical, thoracic, or lumbar anterior spinal fusion. True graft complications occurred in 27 patients (7%) and consisted of fracture (4%), malpositioning (3%), and infection (<1%).     

Imaging Evaluation of the Spinal Hardware: What Residents and Fellows Need to Know

We provide a comprehensive review of the purpose and expected imaging findings of different types of spinal instrumentation. We also demonstrate the imaging evaluation for optimal positioning and assessment of hardware failure.     

Evaluation of the postoperative spine: spinal instrumentation and fusion

Spinal instrumentation is used in a variety of clinical settings ranging from degenerative spine disease to tumors and infection. The primary goal is to provide internal fixation in a region of the spine to facilitate development of an osseous fusion. Hardware is often used to improve alignment and reduce deformities. It is selected based on the anatomic region, ease of implantation and postoperative care, and physician preference. This article will review the basic components of hardware used in the cervical, thoracic, and lumbar spine for anterior and/or posterior fusion. It will not review specific hardware in detail but will discuss general concepts applicable to the various types and strengths and weaknesses of the components. Evaluation of fusion mass will be considered, including some of the current controversies and the current accepted practices.     

Scoliosis in Children: Surgical Management and Postoperative Radiographic Appearances

A component of the evaluation of scoliosis in children is radiography of the spine, initially in anteroposterior and lateral projections. In selected circumstances, additional imaging of the neural axis with magnetic resonance imaging is indicated to identify or exclude an associated spinal cord or neural canal abnormality. The initial management of scoliosis is almost always conservative, employing bracing or casting. When conservative methods fail to control curvature progression, spinal surgery is indicated. A variety of instrumentation devices have been developed in order to reduce and stabilize spinal curvatures. This article will dicuss and illustrate the more frequently used instrumentation devices as well as other selected aspects of spinal surgery.     

单纯后方入路治疗合并强直性脊柱炎颈椎骨折

目的 总结采取单纯后方入路治疗合并强直性脊柱炎下颈椎骨折的特点及治疗效果.方法 分析2003年6月-2008年6月住院治疗的合并强直性脊柱炎颈椎骨折患者26例,分析受伤机制、损伤严蕈程度、救治过程、手术记录、术后随访记录和康复过程,评价术后神经功能恢复程度及骨折愈合情况.结果 有6例患者采取单纯后方人路手术治疗,脊髓损伤按美国脊髓损伤学会(ASIA)分级:A级2例,B级1例,C级2例,D级1例.所有患者均采取后路复位侧块固定融合手术,2例A级患者分别于术后2,3个月因呼吸功能衰竭死亡.其余4例随访37个月(12～54个月),骨折均愈合,愈合时间平均3.8个月(3～5个月),神经功能显著改善.1例患者因发生硬脊膜外血肿症状加重至B级,术后达到D级,C级及D级患者均恢复到损伤前水平,2例A级损伤患者发生低钠血症.本组患者均未发生内固定相关并发症.结论 合并强直性脊柱炎颈椎骨折在骨折端无骨缺损时,复位后对位对线良好者可通过单纯后方入路完成固定融合手术,并可实现骨折稳定愈合.     

Multi-detector CT imaging in the postoperative orthopedic patient with metal hardware

Multi-detector CT imaging (MDCT) becomes routine imaging modality in the assessment of the postoperative orthopedic patients with metallic instrumentation that degrades image quality at MR imaging. This article reviews the physical basis and CT appearance of such metal-related artifacts. It also addresses the clinical value of MDCT in postoperative orthopedic patients with emphasis on fracture healing, spinal fusion or arthrodesis, and joint replacement. MDCT imaging shows limitations in the assessment of the bone marrow cavity and of the soft tissues for which MR imaging remains the imaging modality of choice despite metal-related anatomic distortions and signal alteration.     

Radiographic evaluation of the spine after surgical correction of scoliosis.

Scoliosis is frequently a progressive deformity despite the best efforts at external bracing and various exercises. In childhood, scoliosis is usually insidious and is rarely symptomatic. In later years, however, scoliosis leads to cardiopulmonary compromise, neurologic dysfunction, degenerative joint disease, and cosmetic deformities. Therefore, surgical correction is indicated in selected patients. Internal fixation with spinal fusion is more effective than fusion alone. Postoperative radiographs must be examined closely for general as well as orthopedic complications. Loss of correction and failure of hardware are signs of pseudarthrosis. Radiographic follow-up evaluation should include two views whenever possible.     

Postoperative imaging of the hip

The number and type of operative procedures involving the hip continue to increase, placing a greater emphasis on characterizing patient postoperative condition accurately. Optimal postoperative imaging evaluation may involve multiple modalities, including conventional radiography, radionuclide scintigraphy, and cross-sectional imaging. Many of the surgical procedures involve the placement of metallic joint replacements or fixation that can make the imaging evaluation of the postoperative anatomy challenging. Clinical examination of patients combined with the type of procedure performed direct the appropriate imaging evaluation; adequate clinical knowledge of these procedures and how to optimally image them provide an opportunity to attain the most accurate evaluation possible.     

Traumatic aortic transection associated with a L1/L2 Chance fracture

A case of traumatic aortic transection associated with a L1/L2 Chance fracture associated with the use of a lap seat belt is described. The patient also suffered life-threatening abdominal injuries which included superior mesenteric artery and vein laceration, small and large bowel injury, and traumatic separation of the rectus abdominis muscle. Thirty-seven hours after presentation, the patient underwent aortic interposition graft for terminal aortic rupture and T12–L3 posterior spinal fusion with reduction and instrumentation. This case underlines the importance of careful evaluation following thoracolumbar fractures and reminds spinal surgeons of the incidence of visceral and vascular injuries associated with the Chance fracture.     

上颈椎疾病手术方法选择

 目的 分析上颈椎疾病的病因、寰枢椎复位和脊髓受压情况,探讨上颈椎疾病的手术方法选择.方法 2003-01至2007-06收治169例上颈椎疾病,根据病因分为:上颈椎骨折74例,先天性上颈椎疾病65例,肿瘤21例,其他病因导致寰枢椎不稳9例.根据病因、寰枢椎复位情况和脊髓受压情况分别采用前路手术、后路手术或者前后路手术.结果 28例可复位齿状突骨折患者采用前路空心螺钉内固定.97例上颈椎可复位,脊髓前方无明显受压患者采用单纯后路复位内固定,取自体松质骨植骨融合.44例难复位或脊髓前方明显受压患者采用前路减压、复位,后路内固定、取自体松质骨植骨融合.结论 根据上颈椎疾病病因、复位和脊髓受压情况,应分别选择前路、后路或者前后路联合手术治疗.     

Imaging of hip arthroplasty

The imaging evaluation of the prosthetic hip begins with radiography, but arthrography, aspiration, scintigraphy, sonography, CT and MR imaging all have roles in the evaluation of the painful prosthesis. This article will review the appearance of normal hip arthroplasty including hemiarthroplasty, total arthroplasty, and hip resurfacing, as well as the appearances of potential complications such as aseptic loosening and osteolysis, dislocation, infection, periprosthetic fracture, hardware failure, and soft tissue abnormalities.     

Neurological emergency from rare spinal metalloma: Case report and literature review

Metallosis is a rare and poorly understood long-term complication of instrumented surgery that can result in an inflammatory pseudotumor termed metalloma. We describe a particularly unique case and compare it to 6 analogous cases identified by PubMed and/or Medline search through July 2020. A 79-year-old male with multiple prior spinal lumbar fusion procedures presented with progressive weakness and pain. Imaging revealed a large mass surrounding the right-sided paraspinal rod with extension into the spinal canal, neural foramina, extraforaminal spaces, psoas muscle, marrow spaces, and right sided pedicles. The case presented is a unique example of a unilateral metalloma with mixed-metal instrumentation that created a progressive neurologic deficit without infection, pseudoarthrosis, or hardware failure. This case highlights the lack of understanding regarding the pathophysiology of metallosis and metalloma in spinal instrumentation. We highlight the imaging findings of metalloma to encourage early identification for removal and decompression.     

MR imaging of spinal trauma

Magnetic resonance (MR) imaging plays an increasingly important role in evaluation of the patient who has sustained spinal trauma. This review discusses the role of MR imaging relative to plain radiographs and computed tomography in the evaluation of the patient with spinal trauma and presents a method for systematic review of MR images for assessing spinal injury.     

Technical considerations: CT and MR imaging in the postoperative orthopedic patient

Cross-sectional imaging utilizing computed tomography (CT) and magnetic resonance (MR) imaging have become routine components in the imaging assessment of patients with musculoskeletal disease. Unfortunately, in the setting of a postoperative orthopedic patient with associated orthopedic metallic instrumentation, these imaging techniques are prone to artifacts resulting in image quality degradation. An understanding of the physical basis of such metal-related artifacts, and their appearance on CT and MR imaging, has led investigators to the implementation of a series of techniques and modifications to imaging protocols to decrease CT and MR imaging artifacts in the vicinity of metallic instrumentation. Utilizing such modified imaging techniques, consistent, improved CT and MR image quality may be achieved in imaging of the postoperative orthopedic patient.