The Role of Dynamic Magnetic Resonance Imaging in Cervical Spondylotic Myelopathy

Dynamic spinal cord compression has been investigated for several years, but until the advent of open MRI, the use of dynamic MRI (dMRI) did not gain popularity. Several publications have shown that cervical cord compression is both static and dynamic. On many occasions the evaluation of cervical spondylotic myelopathy (CSM) is straightforward, but patients are frequently encountered with a significantly worse clinical examination than would be suggested by radiological images. In this paper, we present an extensive review of the literature in order to describe the importance of dMRI in various settings and applications. A detailed literature review was performed in the Medline and Pubmed databases using the terms “cervical spondylotic myelopathy”, “dynamic MRI”, “kinetic MRI”, and “myelomalalcia” for the period of 1980-2016. The study was limited to English language, human subjects, case series, retrospective studies, prospective reports, and clinical trials. Reviews, case reports, cadaveric studies, editorials, and commentaries were excluded. The literature search yielded 180 papers, 19 of which met inclusion criteria. However, each paper had evaluated results and outcomes in different ways. It was not possible to compile them for meta-analysis or pooled data evaluation. Instead, we evaluated individual studies and present them for discussion. We describe a number of parameters evaluated in 2661 total patients, including dynamic changes to spinal cord and canal dimensions, transient compression of the cord with changes in position, and the effects of position on the intervertebral disc. dMRI is a useful tool for understanding the development of CSM. It has found several applications in the diagnosis and preoperative evaluation of many patients, as well as certain congenital dysplasias and Hirayama disease. It is useful in correlating symptoms with the dynamic changes only noted on dMRI, and has reduced the incidence of misdiagnosis of myelopathy.

Minimally-Invasive versus Conventional Repair of Spondylolysis in Athletes: A Review of Outcomes and Return to Play

Spondylolysis from pars fracture is a common injury among young athletes, which can limit activity and cause chronic back pain. While current literature has examined the relative benefits of surgical and conservative management of these injuries, no study has yet compared outcomes between conventional direct repair of pars defects and modern minimally invasive procedures. The goals of surgery are pain resolution, return to play at previous levels of activity, and a shorter course of recovery. In this review, the authors have attempted to quantify any differences in outcome between patients treated with conventional or minimally invasive techniques. A literature search was performed of the PubMed database for relevant articles, excluding articles describing conservative management, traumatic injury, or high-grade spondylolisthesis. Articles included for review involved young athletes treated for symptomatic spondylolysis with either conventional or minimally invasive surgery. Two independent reviewers conducted the literature search and judged articles for inclusion. All studies were classified according to the North American Spine Society standards. Of the 116 results of our initial search, 16 articles were included with a total of 150 patients. Due to a paucity of operative details in older studies and inconsistencies in both clinical methods and reporting among most articles, little quantitative analysis was possible. However, patients in the minimally invasive group did have significantly higher rates of pain resolution (p<0.001). Short recovery times were also noted in this group. Both groups experienced low complication rates, and the majority of patients returned to previous levels of activity. Surgical repair of spondylolysis in young athletes is a safe and practical therapy. Current literature suggests that while conventional repair remains effective, minimally invasive procedures better clinical outcomes. We await further data to conduct a more thorough quantitative analysis of these techniques.