The correct combination
Case 137
【Progress】She was given analgesics and thoracic and lumbar corset.
【Discussion】
Human has 27 vertebral discs (6 cervical, 12 thoracic, 5 lumbar). There is no cervical disc between atlas and axis (C1/2). Vertebral disc plays a role of shock absorber and it composes of nucleus pulposus and anulus fibrosus. Nucleus pulposus occupies central portion of disc and contains small amount of collagen and mucoprotein gel (proteoglycan) which is negatively charged, inducing water to come. Anulus fibrosus composes of several fibrocartilage layers (laminae) which are made of type I and type II collagen (1). The stiff laminae can withstand the body weight.
Nucleus pulposus reduces water as age advances, inducing that it becomes hard and stiffness. MRI with T2WI and fat suppression T2WI reflect the images on disk reducing water; Stage 1 whole high signal intensity; Stage II high signal intensity with intranuclear cleft; Stage III whole low signal intensity: Stage IV whole low signal intensity with narrow disc space (2).
Stiff nucleus pulposus push anulus fibrosus which protrude with intact annular fiber (Protrusion). Although anulus fibrosus is intact, nucleus pulposus extrude along with annulus fibrosus (Sub-annular extrusion). Nucleus pulposus extrude with disruption of annulus fibrosus (Transannular extrusion). Nucleus pulposus extrude and torn off annular fibrosis (Sequestered) (2). We term disc hernia in case of Transannular extrusion and Sequestered and disk bulging in case of Protrusion and Sub-annular extrusion.
Further, stiff nucleus pulposus causes fissuring and disruption of endplates and formation of granulation tissue. MRI with T1WI and T2WI show granulation tissue of endplates with low signal intensity and high signal intensity, respectively (Modic I type) in upward vertebrae and downward vertebrae holding stiff disc. As time progress, the granulation tissue changes into fatty yellow marrow (Modic II type) and finally sclerotic fibrosis and calcification (Modic III type) (3).
Furthermore, it happens at times that there is a high intensity zone (HIZ) in the stiff disc on T2WI or fat suppression T2WI. Microscopic examination revealed the marked bright HIZ corresponds to granulation tissue containing the proliferation of new nerve, implying a painful lesion (4-6).
As the causes of compression fracture, metastatic bone tumor, osteoporosis and trauma are listed. Compression fracture due to osteoporosis usually occurs at Th11, Th12 and L1. The hard and stiff disk is considered to be the primary or secondary risk of osteoporotic compression fracture. In our case, MRI with fat suppression T2WI showed compression fractures Th6 and L2 accompanied with L1/2 disc disruption called intra-annular granulation syndrome or disc granulation syndrome.
【Summary】
We present an eighty three-year-old female suffering from thoracic and abdominal pain. MRI with fat depression T2WI showed high signal intensity on vertebrae of Th6 and L2, and L1/L2 disc, implying compression fractures and disk granulation syndrome. It is borne in mind that vertebral disc composes of mucoprotein gel (proteoglycan) (called nucleus pulposus) with negative charge that induce water to come and collagen layers called anulus fibrosus that withstand body weight. As age advances, nucleus pulposus lose water and become hard and stiff. It induces disc movement such as protrusion, sub-annular extrusion, trans-annular extrusion and sequestered. Both of stiff disc and osteoporosis of vertebrae induce compression fracture and/or disc granulation syndrome. The collapsed disc induces vertebrae endplate disruption of Modic 1 type.
【References】
1.Roberts S, et al. Histology and pathology of the human intervertebral disc. J Bone Joint Surg Am. 2006; 88 : 10–4.
2.Weishaupt D et al. MRI of the lumbar spine: Prevalence of intervertebral disc extrusion and sequestration, nerve root compression and plate abnormalities, and osteoarthritis of the fact joints in Asymptomatic Volunteers. Radiology 1998; 209:661-666
3.Rahme R, et al. The Modic Vertebral Endplate and Marrow Changes: Pathologic Significance and Relation to Low Back Pain and Segmental Instability of the Lumbar Spine. American Journal of Neuroradiology May 2008, 29 (5) 838-842
4.Peng B, Hou S, Wu W, et al. The pathogenesis and clinical significance of a high-intensity zone of lumbar intervertebral disc on MR imaging in the patient with discogenic low back pain. Eur Spine J 2006; 15:583-587.
5.Schellhas KP, Pollei SR, Gundry CR, et al. Lumbar disc high-intensity zone: correlation of magnetic resonance imaging and discography. Spine 1996;21:79-86.
6.Lee SH, et al. Intra-Annular Granulation Tissue Syndrome: Clinico-Histological Study of High Intensity Zones and the Role of Percutaneous Endoscopic Lumbar Annuloplasty as Therapy with Two Years Follow-up. Medical Lasers; Engineering, Basic Research, and Clinical Application 2014; 3: 75-83.
2019.2.6