The contribution of cervical dynamic MR imaging to the surgical treatment of cervical spondylotic myelopathy

Abstract

AIm: Cervical spine is the most kinetic segment of the whole vertebrae. The radiologic imaging methods concern with the morphologic changes but give no functional data. At flexion, spinal cord strains, anterior osteophytic compression increases. At extension, spinal canal gets narrower, cord shortens and gets thicker, compression of posterior ligament gets abberant and cord compression increases. mATErIAl and mEThOds: 258 cervical spondylotic myelopathy (CSM) cases were scanned by conventional magnetic resonance imaging (MRI) and additionally dynamic MRI. Contributions of dynamic cervical MRI to the surgical plans and results were evaluated. rEsulTs:We had sagittal and axial T2W MR scans at flexion and extension, in addition to the neutral cervical MR imaging. We found that the AP diameter of spinal canal is increased 14.9 % in flexion and decreased 13.4 % in extension relative to the neutral MR imaging. CONClusION:The changes of the cord compression and the transvers area of cord which is the most important prognostic indicator in spinal diseases and also the area of spinal cord and subarachnoid space can be detected via dynamic axial sections of MRI. Dynamic MR images may be helpfull in the decision making for the surgical treatment of CSM.KEywOrds: Cervical, Cervical spondylotic myelopthy, Dynamic, MRI ÖZ AmAÇ: Servikal vertebra omurganın en hareketli bölümüdür. Radyolojik incelemeler omurga yapısı hakkında bilgi verse de fonksiyonel olarak herhangi bir veri sağlamamaktadır. Fleksiyon duruşunda omurilik gerilir ve ön tarafta yer alan osteofitik değişikliklerin basısı artmaktadır. Ekstansiyon duruşunda ise spinal kanal daralmakta, omurilik kısalmakta ve genişlemekte ve arka tarafta yer alan posterior ligamentlerin basısı artmaktadır. yÖNTEm ve GErEÇlEr: 258 servikal spondilopatik miyelopati hastası klasik MR görüntülerine ek olarak dinamik MR görüntüleri ile incelendi. Dinamik servikal MR görüntülemeleri ile cerrahi planlama ve sonuçları incelendi. BulGulAr:Hastaların fleksiyon ve ekstansiyon duruşunda T2 ağırlıklı sagital ve aksiyel kesitlerine ek olarak nötr duruşta servikal MR görüntüleri elde edildi. Hastaların ön-arka spinal kanal çapı nötral duruşla karşılaştırıldığında fleksiyon duruşunda %14,9 artarken, ekstansiyon duruşunda %13.4 azalmaktadır. sONuÇ: Spinal hastalıklarda spinal kord basısındaki değişiklikler ve spinal kanalın transvers alanındaki değişiklikler prognostik önem taşımaktadır. Spinal kord ve subaraknoid alan ölçümleri dinamik MRG ile elde edilen aksiyel kesitlerden elde edilebilir. Dinamik manyetik rezonans görüntülemeleri servikal spondilopatik miyelopatinin cerrahi kararını vermede yardımcı olmaktadır.

Kinematic magnetic resonance imaging study of the brain stem and cervical cord by dynamic neck motion

“…Miura et al [26] noticed that an average cord distance in the maximum extension position was smaller at the C4/C5 and C5/C6 level. The cervical cord is shorter following extension and it has a larger cross-sectional area [6,14,19,22]. There is a reduction of up to 1.5 mm of the cervical canal diameter, and its shortening after extension [8,13].…”

“…In patients with spondylosis, there is a marked compression of the nerve roots or the spinal cord occasionally by the osteophytes following flexion [6]. Similarly, detection of disc herniation and, eventually, spinal cord compression rises by 5.78-19.46% in the same position [21].…”

“…It seems that the cervical canal here changes its diameter. The other authors registered a slight narrowing of the canal in extension [6,8,13]. Finally, the parameter 's' is decreased in most individuals, which means that the cervical cord at this level is slightly closer to the posterior wall of the spinal canal.…”

“…This is especially true for the corresponding spine and CVJ degenerative diseases [2, 6,21,26,38]. A dynamic MRI examination of the cervical spine and CVJ is very important clinically, because the static MRI can show only morphological changes in this region, but not their behaviour during movements [6,21].…”

“…Endo et al [8] concluded that the canal increases in length after flexion, i.e. its diameter is about 1 mm longer [6,13].…”