The role of cerebrospinal fluid cross-section area ratio in the prediction of dural ossification and clinical outcomes in patients with thoracic ossification of ligamentum flavum

Background It is imperative to preoperatively distinguish dural ossification (DO) and thus anticipate the risks and outcome of the surgery for patients with ossification of ligamentum flavum (OLF). However, studies have disagreed as to the efficacy of the radiographic signs or factors to predict DO and surgical outcome. In additon, the association between the cerebrospinal fluid cross-section area ratio (CCAR) and DO or clinical outcome had not been reported. The purpose of this study was to analyse CCAR and its role in prediction of DO and neurological function recovery rate in patients with OLF. Methods Fifty-two consecutive patients with OLF, who underwent posterior thoracic decompression and fusion between September 2012 and March 2019 at a single institution, were retrospectively reviewed. Demographic data, radiographic signs of DO, CCAR, pre- and postoperative modified Japanese Orthopedic Association (mJOA) score were recorded. Results There were 27 patients in the DO group and 25 patients in the non-DO group, with a mean age at surgery of 57.4 years and 53.9 years, respectively. No significant differences were found in sex, age, segment of maximum compression and preoperative mJOA score between the two groups. The receiver operating characteristic curve showed that the value of CCAR had a relatively high value for diagnosis of DO and prediction of neurological function recovery rate (P = .000). According to the value of CCAR, three zones were defined as DO zone (≤14.3%), non-DO zone (≥44.5%), and gray zone (14.3 to 44.5%). When the value of CCAR≤14.3%, the recovery rate was poor or fair, while it had good or excellent recovery when CCAR≥45.2%. Conclusion The value of CCAR had a high diagnostic value for prediction of DO and neurological function recovery rate in patients with OLF.

The Role of Cerebrospinal Fluid Cross-Section Area Ratio in the Prediction of Dural Ossification and Clinical Outcomes in Patients with Thoracic Ossification of Ligamentum Flavum

Background: It is imperative to preoperatively distinguish dural ossification (DO) and thus anticipate the risks and outcome of the surgery for patients with ossification of ligamentum flavum (OLF). However, studies have disagreed as to the efficacy of the radiographic signs or factors to predict DO and surgical outcome. In additon, the association between the cerebrospinal fluid cross-section area ratio (CCAR) and DO or clinical outcome had not been reported. The purpose of this study was to analyse CCAR and its role in prediction of DO and neurological function recovery rate in patients with OLF.Methods: Fifty-two consecutive patients with OLF, who underwent posterior thoracic decompression and fusion between September 2012 and March 2019 at a single institution, were retrospectively reviewed. Demographic data, radiographic signs of DO, CCAR, pre- and postoperative modified Japanese Orthopedic Association (mJOA) score were recorded. Results: There were 27 patients in the DO group and 25 patients in the non-DO group, with a mean age at surgery of 57.4 years and 53.9 years, respectively. No significant differences were found in sex, age, segment of maximum compression and preoperative mJOA score between the two groups. The receiver operating characteristic curve showed that the value of CCAR had a relatively high value for diagnosis of DO and prediction of neurological function recovery rate ( P=.000). According to the value of CCAR, three zones were defined as DO zone (≤14.3%), non-DO zone (≥44.5%), and gray zone (14.3% to 44.5%). When the value of CCAR≤14.3%, the recovery rate was poor or fair, while it had good or excellent recovery when CCAR≥45.2%.Conclusion: The value of CCAR had a high diagnostic value for prediction of DO and neurological function recovery rate in patients with OLF.

The diagnostic accuracy of CT based “Banner cloud sign” for dural ossification in patients with thoracic ossification of the ligamentum flavum: a prospective, blinded, diagnostic accuracy study protocol

Background Ossification of the ligamentum flavum (OLF) is the most common cause of thoracic spinal stenosis, and responds poorly to conservative treatment, making surgery the only effective method. The existence of dural ossification (DO) makes surgery challenging and increases the risk of intra-/post-operative complications. To date, several methods have been proposed to identify DO, but either the diagnostic accuracy is low or the feasibility is poor. Therefore, the aim of this study is to propose a new imaging sign (Banner cloud sign, BCs), evaluate its diagnostic accuracy in the diagnosis of DO, and provide reliable evidence-based data for its application in clinical practice. Methods This will be a prospective, blinded, diagnostic accuracy study to assess and compare the accuracy of BCs in the diagnosis of DO with other radiologic signs (Tram track sign (TTs) and Comma sign (Cs)). A total of 120 patients who were diagnosed with OLF and underwent decompression in Peking University Third Hospital from January 2018 to June 2019 will be enrolled. Patients’ medical records and imaging data will be retrieved from the hospital database server. An observational group consisting of six spine surgeons of different seniority and two epidemiological researchers will read patients’ images to determine whether there are typical imaging signs and thus the presence of DO. Surgical records will be reviewed to confirm the presence of DO, and the results will serve as the reference standard for estimating accuracy. The primary outcome of the study is to determine the accuracy of BCs for DO diagnosis, and the secondary outcome is to compare the sensitivity, specificity, area under the ROC curve and inter-observer reliability of each imaging sign. The time taken and level of confidence in DO diagnosis of each observer will also be compared. Discussion This study represents the first large investigation of the diagnostic value of “BCs”, “TTs” and “Cs” in the diagnosis of DO, and will provide convincing evidence about their clinical application. Trial registration: Registered on 29 February 2020. Trial number is ChiCTR2000030380