The association between intramedullary increased signal intensity (ISI) on T2-weighted magnetic resonance imaging (MRI) and surgical outcome in thoracic ossification of the ligamentum flavum (OLF) remains controversial. We aimed to determine the impact of signal change ratio (SCR) on thoracic OLF surgical outcomes. We retrospectively reviewed 96 cases of thoracic OLF surgery and investigated myelopathy severity, symptom duration, MRI and computed tomographic findings, surgical technique and postoperative recoveries. Surgical outcomes were evaluated according to the modified Japanese Orthopaedic Association (JOA) score and recovery rate. JOA recovery rate <50% was defined as a poor surgical outcome. By multivariate logistic regression analysis, we identified risk factors associated with surgical outcomes. Forty patients (41.7%) had a recovery rate of <50%. In receiver operating characteristic (ROC) curves, the optimal preoperative SCR cutoff value as a predictor of poor surgical outcome was 1.54. Multivariate logistic regression analysis revealed that a preoperative SCR ≥1.54 and symptom duration >12 months were significant risk factors for a poor surgical outcome. These findings suggest that preoperative SCR and duration of symptoms were significant risk factors of surgical outcome for patients with thoracic OLF. Patients with preoperative SCR ≥1.54 can experience poor postoperative recovery.Thoracic ossification of the ligamentum flavum (OLF) is a relatively rare cause of myelopathy that generally requires surgical treatment owing to its progressive nature and its poor response to conservative therapy. Reportedly, the prevalence of OLF ranges from 3.8% to 26% 1,2 . Patients with thoracic OLF have various symptoms, such as sensory abnormality of the trunk or lower extremities, gait disturbance, and urinary dysfunction 3 . Although decompressive surgery is an available treatment option for this disease, the surgical outcome is not always satisfactory. Prognostic guidelines are still unclear and it is very difficult for the surgeon to predict postoperative recovery.Magnetic resonance imaging (MRI) is a valuable tool before surgical decompression because it allows the visualisation not only of the magnitude of spinal cord compression but also of intramedullary signal intensity. The presence of intramedullary increased signal intensity (ISI) on T2-weighted imaging (WI) in patients with thoracic OLF reflects chronic spinal cord compression. However, the significance of ISI on T2-WI for postsurgical prognosis remains controversial [4][5][6][7][8][9][10][11][12][13][14][15] . Definitive information is not available because most descriptions of signal changes are qualitative in nature. Wang et al. 16 first used signal change ratio (SCR) as a quantifiable measure of signal intensity in cervical compressive myelopathy. This quantitative method may also be used to evaluate the signal change of the spinal cord in thoracic OLF. The purpose of this study was to assess the risk factors associated with poor surgical outcome, pa...

The risk factors of post-laminoplasty kyphosis in patients with cervical spondylotic myelopathy (CSM) without preoperative kyphotic alignment are not well known. This study aimed to compare clinical and radiological data between patients with or without post-laminoplasty kyphosis and to investigate the factors associated with post-laminoplasty kyphosis in CSM patients without preoperative kyphotic alignment. Patients (n = 194) who received unilateral expansive open-door cervical laminoplasty with miniplate fixation and completed a 1-year follow-up were enrolled. Patients were grouped according to whether they suffered from postoperative kyphosis (P) or not (NP). Postoperative kyphosis was observed in 21 (10.8%) patients. The recovery rates of the Japanese Orthopaedic Association scores at the 1-year follow-up in the P group were inferior to those in the NP group (31.9% vs. 65.2%, P < 0.001). Logistic regression with post-laminoplasty kyphosis as the dependent variable showed independent risks associated with an increased C2–7 sagittal vertical axis (SVA, odds ratio [OR] = 1.085, 95% confidence interval [CI] = 1.025–1.203, P = 0.015), destroyed facet joints (OR = 1.132, 95% CI = 1.068–1.208, P < 0.001), and cephalad vertebral level undergoing laminoplasty (CVLL, OR = 2.860, 95% CI = 1.164–6.847, P = 0.021). These findings suggest that CVLL, C2–7 SVA, and destroyed facet joints are associated with kyphosis after laminoplasty in CSM patients without preoperative kyphotic alignment.

The purpose of this study was to characterize risk factors for poor surgical outcome in patients with cervical spondylotic amyotrophy (CSA). We retrospectively reviewed 88 cases of CSA surgery and investigated age, sex, duration of symptoms, atrophy type, preoperative muscle power, signal changes on MRI, anterior horn (AH) or ventral nerve root (VNR) compression, compression levels, surgical approach and postoperative recovery. Fifty (56.8%) patients had good surgical outcome. Logistic regression, with poor outcome as dependent variable, showed independent risks associated with duration of symptoms (OR; 1 for symptom duration less than 3 months versus 3.961 [95% CI; 1.203–13.039, p = 0.024] for symptom duration of 3–6 months versus 18.724 [95% CI; 3.967–88.367, p < 0.001] for symptom duration greater than 6 months), compression type (OR; 1 for VNR versus 4.931 [95% CI; 1.457–16.685, p = 0.010] for AH versus 5.538 [95% CI; 1.170–26.218, p = 0.031] for VNR + AH), and atrophy type (OR; 1 for proximal type versus 6.456 [95% CI; 1.938–21.508, p = 0.002] for distal type). These findings suggest that a long duration of symptoms, AH or both AH and VNR compression, and distal type are risk factors for poor surgical outcome in patients with CSA.