![narrowing of the spine narrowing of the spine](https://sa1s3optim.patientpop.com/assets/images/provider/photos/1467292.jpeg)
A further sub-classification of disc extrusion is a sequestrated disc. In protrusion, the greatest diameter of the herniated disc is less than its base at the site of herniation from the parent disc extrusion describes a herniated disc, which has a maximum diameter greater than its base.
![narrowing of the spine narrowing of the spine](https://www.topdoctors.co.uk/files/Image/large/073eb35769b9df0d6aca308a30dcdf4a.png)
Disc bulge is more diffuse (involving more than 25% of disc circumference) and represents mild (3mm or less), extension of the disc material beyond the disc space bulge may be symmetric or asymmetric.ĭisc herniation may be further classified into protrusion or extrusion. Disc herniation is a broad term that encompasses the various manifestations of degenerative disc disease with extension of disc material beyond the edges of the vertebral body endplates contrary to disc bulge, herniation is a focal extension involving less than 25% of disc circumference. The nomenclature also defines the differences between disc herniation and disc bulge (Figure 4). Zones (central, subarticular, foraminal, extraforaminal and anterior zones) are defined in the axial plane and are illustrated and described in Figure 3. In the sagittal plane, the pedicle serves as a boundary to describe levels with the different levels being disc level, suprapedicle level, pedicle level and infrapedicle level (Figures 1 and 2). The nomenclature clearly defines anatomy in terms of zones and levels in order to standardize localization of pathology. The purpose of the most recent version of the recommendations of combined task force comprised of North American Spine Society (NASS), American Society for Spine Radiology (ASSR), and the American Society of Neuroradiology (ASNR) is to improve communication between radiologists and clinicians. Anatomy, nomenclature, and the combined task force In this article, we will discuss pertinent anatomy, updated nomenclature, indications for imaging, and qualitative and quantitative criteria, illustrating our discussion of stenonis with examples for clarity where appropriate. At the end of their survey, Mamisch et al concluded that while some qualitative criteria were considered important by imaging experts, there were no widely accepted quantitative criteria for the diagnosis of spinal stenosis. 7 In 2012, Mamisch and associates surveyed an expert panel to learn which imaging criteria were considered most important for the diagnosis of spinal stenosis, and to assess the strength of agreement among experts. In 2011, Steurer and associates conducted a review of quantitative radiologic criteria published in the literature, and compiled a list of descriptive terms for lumbar spinal stenosis. The imaging features may be roughly classified into two categories qualitative and quantitative findings. The diagnosis of spinal stenosis relies primarily on imaging to provide objective evidence of neurovascular compromise. Their recommendations for lumbar disc nomenclature were released in 2001 and revised in 2014. In response, a combined task force of radiologists and orthopedic surgeons endorsed a set of radiologic criteria for spinal stenosis in hope of improving communication among healthcare providers. 4 This variability and lack of standardization may contribute to increased heterogeneity of the patient population undergoing surgery for spinal stenosis, rendering any analysis of surgical outcomes difficult at best. The variability in description and reporting of spinal stenosis among radiologists and other physicians is well-documented.
![narrowing of the spine narrowing of the spine](https://vhscollector.com/sites/default/files/vhsimages/2019-06/vamp-vhs-1-13129.jpg)
Given that spinal stenosis is the most common reason for lumbar spine surgery in patients over 65 years, 2 and that many patients with anatomic narrowing are asymptomatic, 3 there is a recognized need for standardizing descriptive radiologic terms for spinal stenosis. 1 Classically, patients with spinal stenosis complain of lower-extremity pain exacerbated by walking and relieved by bending forward or sitting. Degenerative lumbar spinal stenosis is a condition in which there is diminished space available for the neural and vascular elements in the lumbar spine secondary to degenerative changes in the spinal canal.