Intramedullary Lesion Length on Postoperative Magnetic Resonance Imaging is a Strong Predictor of ASIA Impairment Scale Grade Conversion Following Decompressive Surgery in Cervical Spinal Cord Injury

Abstract

BACKGROUND Evidence indicates that, over time, patients with spinal cord injury (SCI) improve neurologically in various degrees. We sought to further investigate indicators of grade conversion in cervical SCI. OBJECTIVE To detect predictors of ASIA impairment scale (AIS) grade conversion in SCI following surgical decompression. METHODS In a retrospective study, demographics, clinical, imaging, and surgical data from 100 consecutive patients were assessed for predictors of AIS grade conversion. RESULTS American Spinal Injury Association motor score was 17.1. AIS grade was A in 52%, B in 29%, and C in 19% of patients. Surgical decompression took place on an average of 17.6 h following trauma (≤12 h in 51 and >12 h in 49). Complete decompression was verified by magnetic resonance imaging (MRI) in 73 patients. Intramedullary lesion length (IMLL) on postoperative MRI measured 72.8 mm, and hemorrhage at the injury epicenter was noted in 71 patients. Grade conversion took place in 26.9% of AIS grade A patients, 65.5% of AIS grade B, and 78.9% of AIS grade C. AIS grade conversion had statistical relationship with injury severity score, admission AIS grade, extent of decompression, presence of intramedullary hemorrhage, American Spinal Injury Association motor score, and IMLL. A stepwise multiple logistic regression analysis indicated IMLL was the sole and strongest indicator of AIS grade conversion (odds ratio 0.950, 95% CI 0.931–0.969). For 1- and 10-mm increases in IMLL, the model indicates 4% and 40% decreases, respectively, in the odds of AIS grade conversion. CONCLUSION Compared with other surrogates, IMLL remained as the only predictor of AIS grade conversion.

Efficacy of Ultra-Early (< 12 h), Early (12–24 h), and Late (>24–138.5 h) Surgery with Magnetic Resonance Imaging-Confirmed Decompression in American Spinal Injury Association Impairment Scale Grades A, B, and C Cervical Spinal Cord Injury

“…Admission T2-weighted and short T1 inversion recovery (STIR) sequences were used to measure the IMLL and the extent of spinal cord compression/decompression before and after surgery. 18,35 An attending trauma neuroradiologist and the principal investigator independently measured the IMLL, and the mean value was taken for statistical analysis. 18…”

“…18,35 An attending trauma neuroradiologist and the principal investigator independently measured the IMLL, and the mean value was taken for statistical analysis. 18…”

“…13,17 Frequently, by the time the victim is transferred to the trauma center, intramedullary lesion length (IMLL), can measure between 40 and 100 mm in length, far beyond the cross-sectional injury epicenter. [18][19][20] Pre-clinical studies indicate that the longer the spinal cord is compressed, the more severe is the parenchymal damage and loss of function. [21][22][23][24] Together, these findings have encouraged many trauma spine surgeons to recommend early operative intervention as a neuroprotective measure in order to promote neurological improvement.…”

“…[25][26][27][28][29][30] Ongoing surgical studies on the relationship among imaging biomarkers, surgical strategy, and long-term clinical outcome are shaping the standard of care for these patients. 18,28,[31][32][33][34][35][36] Over the past 30 years, overarching evidence has supported spinal cord decompression following trauma, but the question of surgical timing has yet to be established within this evolving paradigm. 10,12,32,35,[37][38][39][40][41] In addition, although multiple reports have indicated that early anatomical alignment of the spinal column and decompression of the spinal cord followed by internal fixation is neuroprotective, in these studies, decompression of the spinal cord generally has not been verified by post-operative imaging.…”

Establishing the inter-rater reliability of spinal cord damage manual measurement using magnetic resonance imaging

“…Edema is commonly observed on T 2 -weighted MRI as an irregularly shaped characterization of hyperintensity to indicate areas of the damaged cord [5]. While a variety of measures for quantifying the extent of edema have been reported [5,[7][8][9][10][11][12][13][14][15][16] and associated with functional recovery [5,7,8], more evidence is needed to establish the psychometric properties of these measurements.…”