Prognostic relevance of the postoperative evolution of intramedullary spinal cord changes in signal intensity on magnetic resonance imaging after anterior decompression for cervical spondylotic myelopathy

Abstract

<jats:sec> <jats:title>Object</jats:title> <jats:p>Areas of intramedullary signal intensity changes (hypointensity on T1-weighted magnetic resonance [MR] images and hyperintensity on T2-weighted MR images) in patients with cervical spondylotic myelopathy (CSM) have been described by several investigators. The role of postoperative evolution of these alterations is still not well known.</jats:p></jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>A total of 47 patients underwent MR imaging before and at the end of the surgical procedure (intraoperative MR imaging [iMRI]) for cervical spine decompression and fusion using an anterior approach. Imaging was performed with a 1.5-tesla scanner integrated with the operative room (BrainSuite). Patients were followed clinically and evaluated using the Japanese Orthopaedic Association (JOA) and Nurick scales and also underwent MR imaging 3 and 6 months after surgery.</jats:p></jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>Preoperative MR imaging showed an alteration (from the normal) of the intramedullary signal in 37 (78.7%) of 47 cases. In 23 cases, signal changes were altered on both T1- and T2-weighted images, and in 14 cases only on T2-weighted images. In 12 (52.2%) of the 23 cases, regression of hyperintensity on T2-weighted imaging was observed postoperatively. In 4 (17.4%) of these 23 cases, regression of hyperintensity was observed during the iMRI at the end of surgery. Residual compression on postoperative iMRI was not detected in any patients.</jats:p> <jats:p>A nonsignificant correlation was observed between postoperative expansion of the transverse diameter of the spinal cord at the level of maximal compression and the postoperative JOA score and Nurick grade. A statistically significant correlation was observed between the surgical result and the length of a patient's clinical history. A significant correlation was also observed according to the preoperative presence of intramedullary signal alteration. The best results were found in patients without spinal cord changes of signal, acceptable results were observed in the presence of changes on T2-weighted imaging only, and the worst results were observed in patients with spinal cord signal changes on both T1- and T2-weighted imaging. Finally, a statistically significant correlation was observed between patients with postoperative spinal cord signal change regression and better outcomes.</jats:p></jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>Intramedullary spinal cord changes in signal intensity in patients with CSM can be reversible (hyperintensity on T2-weighted imaging) or nonreversible (hypointensity on T1-weighted imaging). The regression of areas of hyperintensity on T2-weighted imaging is associated with a better prognosis, whereas the T1-weighted hypointensity is an expression of irreversible damage and, therefore, the worst prognosis. The preliminary experience with this patient series appears to exclude a relationship between the time of signal intensity recovery and outcome of CSM.</jats:p></jats:sec>

Magnetic Resonance T2 Image Signal Intensity Ratio and Clinical Manifestation Predict Prognosis After Surgical Intervention for Cervical Spondylotic Myelopathy

“…Some authors reported that patients with ISI have poor prognosis after surgery 2-6 ; however, others found no correlation between surgical outcome and intramedullary high SI on T2WI. [7][8][9][11][12][13] As far as we know, Takahashi et al first reported the MR findings of intramedullary high SI in CSM. They considered intramedullary high SI as an indicator of poor prognosis.…”

“…However, the significance of ISI for prognosis remains controversial. [2][3][4][5][6][7][8][9][10][11][12] In this context, the aim of this study is to quantize signal intensity (SI) ratio and to determine whether MR T2 image SI ratio and clinical manifestation can contribute to assess the prognosis of the disease. …”

Multilevel oblique corpectomy for cervical spondylotic myelopathy preserves segmental motion

“…Duration of preoperative symptoms greater than 12 months has been associated with poorer outcomes [24,25]. Although many authors are not impressed with intramedullary MR changes as a predictor of outcome, some data exists to suggest that T1 hypointensity along with T2 hyperintensity within the cord, particularly if multisegmental, are associated with poor outcomes and probably an irreversible pathology [26,27].…”

Change in Morphology of Intramedullary T2-Weighted Increased Signal Intensity After Anterior Decompressive Surgery for Cervical Spondylotic Myelopathy

“…Similar fi ndings have been described by other authors. 6 , 8 Mastronardi et al , 7 studying 37 patients with intramedullary ISI after anterior cervical discectomy, showed that 12 patients with regression of T2-weighted signal change had improvements in both modifi ed Japanese Orthopaedic Association scores and Nurick grades. Although the presence of persistent focal T2W ISI (similar to type 2 ISI) at 6 months postoperatively has been shown to predict clinical outcome at 1 year, 10 it is unclear if intramedullary MR signal change beyond the fi rst year after surgery is of prognostic value.…”

“…6 In addition, there are inconsistent data on the clinical correlates of changes in ISI characteristics on postoperative imaging. [7][8][9][10] In this study, we evaluated change in the type of T2W ISI in a series of patients after central corpectomy for CSM or ossifi ed posterior longitudinal ligament (OPLL). We also aimed to determine if a change in ISI postoperatively was associated with functional outcome after surgery.…”