Dural ossification associated with ossification of ligamentum flavum in the thoracic spine: a retrospective analysis

Abstract

ObjectivesTo investigate the incidence, distribution and radiological characteristics of dural ossification (DO) associated with ossification of ligamentum flavum (OLF) in the thoracic spine.DesignA retrospective radiographical analysis.SettingThis study was conducted at a single institution in China.Participants53 patients with OLF who underwent posterior decompression surgery between January 2011 and July 2015 in a single institution were enrolled in this study. The decompression segments were grouped according to imaging evaluation and intraoperative evidences.Outcome measuresThe demographic distribution, radiological data and detailed surgical records were collected. First, preoperative CT images of decompressed segments were evaluated to identify imaging signs of DO. The ‘tram tack sign’ (TTS), ‘comma sign’ and ‘bridge sign’ were considered as characteristic imaging findings of DO in OLF. 4 kinds of confusing signs (false TTS) were identified and excluded. Then detailed surgical records were reviewed to finally identify segments with DO.ResultsThe incidence of DO in patients with OLF was 43.4%. The incidence of DO in OLF segments was 21.5%. OLF was more common in the lower thoracic spine, and more than half (53.8%) of the DO was located in T9-T12. TTS was the most common sign, but it might be misdiagnosed. After excluding 4 kinds of false TTS, the sensitivity and specificity of imaging diagnosis were 94.23% and 94.21%, respectively.ConclusionsDO was relatively common in thoracic OLF, especially in T9-T12. TTS might be misdiagnosed. After excluding 4 kinds of false TTS, the accuracy of imaging diagnosis was relatively high.

Bilateral translaminar osseous-channel assisted percutaneous full-endoscopic ligamentectomy decompression for thoracic myelopathy due to ossification of the ligamentum flavum: a technical note.

“…Multiple symptoms, including radicular and/or myelopathic symptoms, may occur [25,26]. Due to the progressive nature of OLF and the finding that it is refractory to conservative treatment, surgical intervention is recommended once neurological symptoms are present [5,27]. On the other hand, surgery is also facilitated to avoid the occurrence of irreversible damage to the spinal cord after minor trauma, which has a pathological basis in the thoracic spinal stenosis caused by OLF [7,28].…”

Computer-Based 3D Simulations to Formulate Preoperative Planning of Bridge Crane Technique for Thoracic Ossification of the Ligamentum Flavum

“…Nevertheless, these methods usually need to invade the spinal canal and remove the ossified mass directly, which can damage the spinal cord [37]. The high risk of early complications such as neurological deficits and cerebrospinal fluid (CSF) leakage are also why it is hard to achieve satisfactory clinical outcomes using these surgical methods [6][7][8][9].…”

“…Due to its progressive feature and poor efficacy for conservative therapy, surgical treatment is usually a preferred choice [4,5]. However, the clinical outcomes of surgical intervention are often unsatisfactory and its risk is also high, which is accompanied by various complications such as cerebrospinal fluid leakage and neurological deficit [6][7][8][9].…”

Thoracic myelopathy secondary to multi-level ossification of the ligamentum flavum in an Asian patient

“…[11] OLF frequently co-exists with OPLL, ossification of the dura and cervical/lumbar spondylosis. [11,12] This may contribute to a delay in diagnosis and complicate management.…”