Cervical myelopathy is caused by compression of the cervical spinal cord for any reason. Cervical myelopathy most commonly affects the C5-6 level. However, C7-T1 single-level myelopathy is rare, and neurological findings may be atypical, making diagnosis difficult. We report three cases and discuss their clinical manifestations. Unlike other levels of cervical myelopathy, C7-T1 single-level myelopathy may present with gait disturbance without neurological deficits in the upper extremities. In addition, all three of our cases had different levels of spinal cord compression and locations of sensory deficits; at the C7-T1 level, the spinal cord compression may not correspond to the site of the sensory deficit. These features may help clinicians in the diagnosing of myelopathy.

Cervical flavum ligament ossification (C-OLF) is very rare source of myeloradiculopathy. Less than 100 cases have been reported in modern English literature up to 2020. Association between C-OLF and Diffuse Idiopathic Skeletal Hyperostosis (DISH) at cervical level has never been described.

In this article we performed a systematic review about epidemiology, physiopathology, clinical and surgical management of C-OLF. Moreover, we research its possible association with other cervical spine ligament ossification and in particular with anterior longitudinal ligament ossification. We report a case of 73 years-old woman experiencing mild cervical myeloradiculopathy caused by C6-C7 C-OLF compression and coexistence of DISH at cervico-thoracic level. A brief technical note about intraoperative management of C-OLF has also been described.

Our research found 81 previous reported case of C-OLF. The coexistence of Posterior longitudinal ligament ossification has been reported in 21.3% of C-OLF case. Conversely, we reported the first case describing the association between DISH and C-OLF. Posterior surgical decompression is the only useful treatment providing good long-term functional outcome. Instrumentation should be tailored according to pre-operative findings.

C-OLF is a rare source of myeloradiculopathy and it may coexists with DISH probably due to alteration in the cervical mechanical stress and tendency of bone formation in patients harboring coexistent ligament ossifications. According to our result, skip en-bloc microsurgical laminectomy is safe and less invasive method to avoid complication and to provide optimal cervical spinal cord and nerve decompression avoiding CSF-leak.

Cervical ossification of ligamentum flavum (COLF) is a rare clinical entity which can occasionally contribute to severe myeloradiculopathy. Many orthopedists are unfamiliar with or underestimate this pathology. Therefore, a comprehensive research is obligatory to reappraise the epidemiological, radiological, clinical and histopathological characteristics of COLF-myeloradiculopathy based on synthesis of individual patient data.

Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, PubMed, EMBASE, Scopus and Web of Science databases were searched for studies discussing COLF-myeloradiculopathy from the inception to December 2020.

A total of 94 cases from 54 studies were identified. The annual publications demonstrated a steady increase, and most reports were from Japan and China. The mean age was 58.76±13.39 years and nearly 60% of cases occurred in the 55-64 and 65-74 years age group. The male-female ratio was 1.4:1. Most cases belonged to East Asian population (60.64%). COLF predominately appeared in the lower cervical and cervicothoracic spine (76.60%) and mainly affected C4-5 (23.29%) and C5-6 (21.23%). Single-segment type ossification accounted for 62.76 and 45.45% of ossification lesions distributed bilaterally. The majority of COLF (81.1%) were spontaneous, and motor disturbance (76.4%), spinal ataxia (62.5%) and sensory disturbance (58.9%) were the most common manifestations. Histopathologically, it's a metaplastic process of endochondral ossification with the formation of mature lamellar bone which was distinguished from calcification of ligamentum flavum. About 21.28% of concurrent COLF and COPLL cases were identified as a separated group, with unique characteristics.

COLF is an underappreciated but potentially growing pathogeny of myeloradiculopathy in aging population, though its distinct epidemiological, radiological, clinical and histopathological features are not fully supported by current evidence. However, our findings will provide several referential data for future researches to shed light on COLF.

Ossification of the ligamentum flavum (OLF) occurs mostly in adult males, typically in the thoracolumbar spine where it may contribute to neurological deficits. Here we reviewed 68 cases of cervical OLF resulting in progressive quadriparesis.

The literature on cervical OLF was reviewed between 1962 and 2018 along with the case of an 81-year-old male with progressive quadriparesis attributed to cervical OLF.

Most patients with cervical OLF are Asian, with Caucasians constituting the second most frequently impacted population.

Cervical OLF is typically reported in the Asian, followed by the Caucasian population, and is most often found in the thoracolumbar spine. Here we presented an 81-year-old male with cervical OLF contributing to quadriparesis.

Cervical myelopathy is a well-described clinical syndrome that may evolve from a combination of etiological mechanisms. It is traditionally classified by cervical spinal cord and/or nerve root compression which varies in severity and number of levels involved. The vast array of clinical manifestations of cervical myelopathy cannot fully be explained by the simple concept that a narrowed spinal canal causes compression of the cord, local tissue ischemia, injury and neurological impairment. Despite advances in surgical technology and treatment innovations, there are limited neuro-protective treatments for cervical myelopathy, which reflects an incomplete understanding of the pathophysiological processes involved in this disease. The aim of this review is to provide a comprehensive overview of the key pathophysiological processes at play in the development of cervical myelopathy.

Large scale, cross-sectional imaging study of a general population.

To evaluate the prevalence, morphology, and distribution of ossification of the ligamentum flavum (OLF) in a population, and synthesize the scientific literature on the prevalence of OLF and some factors associated with its occurrence.

OLF is a rare disease in which the pathogenesis has not been conclusively established. Little is known about its epidemiology. To date, there is no study that comprehensively assessed the distribution and prevalence of OLF in the whole spine using magnetic resonance imaging (MRI).

A total of 1736 southern Chinese volunteers (1068 women; 668 men) between 8 and 88 years of age (mean, 38 years) were recruited by open invitation. MRI was administered to all the participants. T2-weighted, 5-mm spin-echo MRI sequences of the whole spine were obtained. Presence of OLF was identified as an area of low signal intensity in the T2 sagittal sequence located in the posterior part of the spinal canal, and subsequently confirmed by computed tomography scans showing areas of ossification within the ligamentum flavum. The distribution of OLF was classified into 3 types: the isolated type, continuous type, and noncontinuous type. While the morphology of the lesion was classified into triangular, round, and beak shapes based on the pattern of ossification on T2-weighted sagittal MRIs.

OLF was identified in a total of 66 subjects or 3.8% of the population (52 women and 14 men). In 45(68.2%) cases, OLF was present at a single-level (isolated type), whereas in 21 (31.8%) cases OLF was present at multiple levels. The isolated type was found in 45 (68.2%) cases, continuous type in 11 (16.7%), and noncontinuous type in 10 (15.2%). The most common site of involvement is the lower thoracic spine, but they can also occur in the upper thoracic spine. The majority of the segments had a round morphology (n = 75: 81.5%), while 17 (18.5%) segments were triangular in shape. A literature review of the past 26 years showed only 4 reports on the prevalence of OLF, all were in special patient groups.

Case reports have described postoperative paraplegia from failure to identify and decompress all stenotic segments of OLF. This study demonstrated that OLF is not uncommon, and that some 15% of the lesions are noncontinuous, and therefore could be missed. The authors recommend that for patients undergoing surgical decompression for 1 level of OLF, the whole spine should be routinely screened for other stenotic segments. Failure to do so could result in paraplegia from the nondecompressed levels.

A retrospective review.

The aim of this study is to highlight one of the under recognized and under reported aspects of ossification of the ligamentum flavum (OLF), namely, dural ossification in OLF and to discuss the incidence, radiologic signs, causes as well as the surgical and prognostic implications of dural ossification in OLF.

OLF is being increasingly recognized as a cause of myelopathy. One of the surgical pitfalls in the management of this condition is ossification of the dura mater in OLF. Preoperative identification of ossified dura mater will be helpful to the surgeon to modify the surgical technique and to counsel patients regarding the risks of surgery.

A retrospective analysis of a database of OLF maintained by this author was done to identify cases of OLF where there was intraoperative evidence of dural ossification and dural laceration. Only those patients who had both computed tomography (CT) and magnetic resonance imaging (MRI) were included in the analysis. Patients with MR imaging alone were excluded from the analysis as CT evaluation was not done routinely in the earlier part of the study. Nurick's grading was used to assess the neurologic status before and after surgery. The CT and MR images of these patients were analyzed to identify radiologic signs of dural ossification. The pattern of dural ossification, if present, was noted. The intraoperative and postoperative complications were recorded.

During the study period from 1997 to 2006, there were 20 patients with OLF who had both CT and MR imaging evaluation. Of these 20 patients, 8 had intraoperative evidence of dural ossification and these patients also sustained dural laceration during surgery. Of these 8 patients, CT evidence of dural ossification was found in 7. In the remaining one patient, there was no radiologic evidence of dural ossification. The radiologic signs of dural ossification as depicted in the bone windows of CT were of 2 types: (1) the "tram track sign," where there was a hyperdense bony excrescence with a hypodense center and (2) the "comma sign," where there was evidence of ossification of one-half of the circumference of the duramater. Of these 7 patients, 4 developed cerebrospinal fluid (CSF) leak following surgery and 1 of these 4 patients developed meningitis. Neurologic function improved by one Nurick's grade in 5 of the 7 patients. In the remaining 2 patients, there was no change in the neurologic status.

Dural ossification is a common finding in OLF. There are 2 radiologic signs of dural ossification, namely, the "tram track sign" and the "comma sign." Preoperative identification of dural ossification might help the surgeon to anticipate and appropriately deal with dural laceration during surgery. This will also help to counsel patients regarding the risks of surgery for OLF. The surgical and prognostic implications of dural ossification are being discussed.

Cervical myelopathy is caused by degenerative processes of the spine including intervertebral disc herniation and posterior spur usually developing at C3/4 to C5/6. C7/T1 single level myelopathy is very rare because of the anatomical characteristics. Facet joint arthrosis can be a cause of cervical myelopathy but only a few cases have been reported. The authors report an extremely rare case of C7/T1 myelopathy caused by facet joint arthrosis. A 58-year-old male presented with hand and gait clumsiness. The radiological examinations revealed severe C7/T1 facet joint arthrosis with bony spur extending into the spinal canal, which compressed the spinal cord laterally. The T1 spinous process indicated nonunion of a "clay-shoveler's" fracture, which suggested that his cervico-thoracic spine had been frequently moved, and thus severe arthrosis had occurred in the facet joints. A right hemilaminectomy of C7 and C7/T1 facetectomy with single level spinal fusion led to complete neurological improvement.

Ossification of the ligamentum flavum (OLF) commonly occurs in the thoracic and lumbar regions. We present a patient with OLF at the C4-5 level with presentation as Brown-Sequard syndrome. Symptoms were relieved following a laminectomy and total lesion excision. The relevant literature is reviewed to discuss the racial distribution, unique presentation and pathogenesis of OLF.

Cervical myelopathy is a group of closely related disorders usually caused by spondylosis or by ossification of the posterior longitudinal ligament and is characterized by compression of the cervical spinal cord or nerve roots by varying degrees and number of levels. The decrease in diameter of the vertebral canal secondary to disc degeneration and osteophytic spurs compresses the spinal cord and nerve roots at one or several levels, producing direct damage and often secondary ischemic changes.

Clinicians who treat cervical myelopathy cord injuries should have a basic understanding of the pathophysiology and the processes that are initiated after the spinal cord has been injured.

Literature review.

Literature review of human cervical myelopathy and clinically relevant animal models to further our understanding of the pathological mechanisms involved.

The pathophysiology of cervical myelopathy involves static factors, which result in acquired or developmental stenosis of the cervical canal and dynamic factors, which involve repetitive injury to the cervical cord. These mechanical factors in turn result in direct injury to neurons and glia as well as a secondary cascade of events including ischemia, excitotoxicity, and apoptosis; a pathobiology similar to that occurring in traumatic spinal cord injury.

This review summarizes some of the significant pathophysiological processes involved in cervical myelopathy.

Case report.

To describe an extremely unusual case of acute quadriparesis in a white female caused by calcification of the ligamentum flavum (LF) from C1 to T2, and to review briefly the pertinent literature.

Diseases characterized by abnormal calcium deposition on the spinal ligaments have an unclear etiology. The overwhelming majority of these cases has been reported in people of Asian descent and has a predilection for the thoracic spine. Multilevel involvement of the cervical LF in white patients is exceptionally rare. To our knowledge, complete calcification of the entire cervical LF has not been previously reported in the literature.

The history, physical examination, and radiographic studies of a 64-year-old white female with a history of scleroderma are described. The patient presented with neck pain and acute quadriparesis caused by spinal cord impingement by calcified cervical LF from C1 to T2. The patient underwent emergent C3-C7 laminectomy and C2-C7 posterior spinal fusion.

Operative intervention resulted in marked neurologic improvement and relief from neck pain. Histopathologic examination of the calcified LF showed that the deposits consisted of hydroxyapatite crystals exclusively with no heterotopic bone. However, kyphosis did develop in the patient after laminectomy.

To our knowledge, this unusual case of complete calcification of the entire cervical LF has not previously been described. Multilevel laminectomy and fusion can improve neurologic function but may result in kyphosis.