Ossification of the ligamentum flavum. A case report and its MRI finding

Ossification of the Ligamentum Flavum in a Nineteenth-Century Skeletal Population Sample from Ireland: Using Bioarchaeology to Reveal a Neglected Spine Pathology

Ossification of the ligamentum flavum of the spine (OLF) is rarely reported in individuals of European ancestry. It has, however, been observed in archaeological skeletons from Europe. The aim of this study was to revisit OLF rates, utilising a mid-nineteenth-century skeletal sample from Ireland. The hypothesis was that the OLF prevalence rate was similar to studies on non-Europeans. Spines from 345 individuals were analysed, and the extent of OLF recorded on the cranial and caudal attachment sites of each vertebra using the following classification system: Grade 0 (no change); Grade 1 (<2 mm); Grade 2 (2–4 mm); Grade 3 (≥4 mm). OLF was observed at prevalence rates of 83.6%. There was no disparity in prevalence based on sex, except for individuals aged 36–45 years at death in which the male rate was higher. Advancing age was a determining factor in the OLF occurrence with an onset in young adulthood (18–25 years), and most severe grades occurring over the age of 25 years. OLF coincides with spinal osteoarthritis, spondylosis deformans and Schmorl’s nodes in both sexes, and with intervertebral osteochondrosis in females. The results of this study indicate that OLF is likely to be an understudied rather than rare condition in European populations.

Clinical characteristics and surgical outcome of thoracic myelopathy caused by ossification of the ligamentum flavum: a retrospective analysis of 85 cases

STUDY DESIGN

A retrospective comparative study.

OBJECTIVES

To describe the clinical features and radiological findings, to assess the safety and effectiveness of posterior decompressive laminectomy and resection of the ossification of the ligamentum flavum (OLF), and to determine which presurgical and surgical variables were most closely related to postsurgical prognosis of thoracic myelopathy (TM) caused by OLF in China.

METHODS

Eighty-five patients with the diagnosis of TM caused by OLF received surgical treatment from July 1998 to May 2012. Clinical data were collected from medical and operative records. Correlations between the surgical outcome and various factors were also analyzed.

RESULTS

All cases were followed up for a mean of 49.2 months (range, 24-190 months) postoperatively. The mean Japanese Orthopaedic Association score was 3.8 points preoperatively and 8.2 points at the final follow-up, yielding a mean recovery rate of 63.0%. Postoperative complications included transient neurological deficits (9 cases), persistent neurological deficits (4 cases), dural tears (17 cases), cerebrospinal fluid leakage (9 cases), wound dehiscence (2 cases) and wound infection (3 cases). The OLF level (middle thoracic), preoperative duration of symptoms, intramedullary signal change on T2WI and preoperative severity of myelopathy were important predictors of surgical outcome.

CONCLUSIONS

Biomechanical and anatomical factors may have a key role in thoracic OLF progression. Posterior decompressive laminectomy and resection of the OLF can be considered an effective, reliable and safe alternative procedure. The OLF level, preoperative duration of symptoms, intramedullary signal change on T2WI and preoperative severity of myelopathy were confirmed and significantly correlated with the surgical outcome.

Upper facet joint en bloc resection for the treatment of thoracic myelopathy caused by ossification of the ligamentum flavum

OBJECT

The authors introduce a novel technique to treat thoracic myelopathy caused by ossification of the ligamentum flavum (OLF): upper facet joint en bloc resection. This surgical procedure avoids surgery to the most heavily compressed cord surface, contact with the cord, and cord injury. The epidural venous plexus bleeding point can be directly seen and easily controlled during the decompression.

METHODS

Between January 2007 and January 2009, thoracic myelopathy caused by OLF was diagnosed in 38 patients using plain radiography, CT, and MRI, and diagnoses were confirmed by postoperative pathological examination. All upper facet joint en bloc resection procedures were performed in 2 steps. First, the bony structures above the upper facet joint surfaces were resected and the upper facet joints were isolated. Second, en bloc resection of the upper facet joint was performed by dissection of the junction between the pedicle and upper facet joint. Intraoperative neurological monitoring was performed in all cases. The modified Japanese Orthopaedic Association (mJOA) scoring system was used to assess neurological status. The degree of postoperative expansion of the spinal cord was calculated on axial MR images. The pre- and postdecompression Cobb angle was applied to assess the magnitude of local kyphosis.

RESULTS

Of the 38 cases of OLF, 6 were single level, 12 were double level, and 20 were multilevel. Of the 92 ossified segments in this study, 23 (25.0%) were located in the upper thoracic spine (T1-4), 13 (14.1%) were located in the midthoracic spine (T5-8), and 56 (60.9%) were located in the lower thoracic spine (T9-L1). The mean intraoperative blood loss was 340 ± 54 ml. The neurological status improved during follow-up (mean 46.1 months) from a preoperative mean mJOA score of 5.39 ± 1.52 to 8.97 ± 1.22 points (t = 18.39, p < 0.05). The neurological function recovery rate ranged from 28.6% to 100%. The mean increase in pre- and postoperative kyphosis of the involved vertebrae was only 1.3° ± 1.6°. The increase in the cross-sectional area of the dural sac at the level of maximum compression suggested that decompression was complete.

CONCLUSIONS

Upper facet joint en bloc resection is effective and may be a reasonable alternative treatment choice for thoracic myelopathy caused by OLF.

Ossification of ligamentum flavum in Middle East Arabs: a hospital-based study

OBJECTIVE

To investigate the frequency of ossification of the ligamentum flavum (OLF) in the spine among the Arab population in Kuwait using magnetic resonance imaging (MRI) surveillance of the whole spine.

SUBJECTS AND METHODS

A consecutive series of 102 patients with low back pain were recruited from the outpatient clinic of Mubarak Al-Kabeer Hospital, Kuwait. MRI of the whole spine in the sagittal plane was obtained in at least two sequences (T(1) and T(2)). The OLF was defined as low signal intensity thickening of the ligament in both T(1) and T(2) sequences on the posterior margin of the spinal canal, causing indentation of the theca with or without cord compression.

RESULTS

Of the 102 cases, 19 (18.6%) patients had OLF. Of the 19 positive cases, 12 (63.2%) were present at a single level, and 7 (36.8%) at multiple levels. A total of 26 OLF segments were identified in the following anatomical distribution: cervical: 15 (57.7%); upper thoracic (T1-T4): 1 (3.8%); mid thoracic (T5-T8): 4 (15.4%); lower thoracic (T9-T12): 4 (15.4%), and lumbar region: 2 (7.7%). Of the 19 OLF patients, 2 (10.5%) had tandem ossification of the posterior longitudinal ligament in the cervical spine and were symptomatic.

CONCLUSIONS

The frequency of OLF appears to be high among this hospital-based cohort of the Arab population. OLF should be kept in mind if a patient presents with radiculopathy, particularly in the cervical region, for which surgical intervention is contemplated.

Surgical treatments of myelopathy caused by cervical ligamentum flavum ossification

OBJECTIVE

To present a small case series reporting the outcomes of surgical treatment for myelopathy caused by cervical ossification of the ligamentum flavum (OLF).

METHODS

The authors assessed 15 cases of myelopathy caused by cervical OLF. Patients were eight women and seven men 37-75 years old (mean age 59.7 years). All patients underwent bilateral laminectomy, and the lesions were removed. The decompression range was confined within the medial sides of the bilateral facets and within the involved segments. Intraoperative specimens were examined histologically to confirm the diagnosis. During the operation, the extent of adherence of the lesions to the dura was recorded. The patients were followed for 3-70 months. Neurofunctional improvements were evaluated with the Japanese Orthopaedic Association (JOA) score.

RESULTS

Definite adherences were present in 67.7% of all cases. JOA score showed a 71.5% improvement after operation from a preoperative score of 5-8 (mean 6.4) to a postoperative score of 10-14 (mean 13.5). The operative outcomes were satisfactory without extensive decompression of adjacent segments.

CONCLUSIONS

A high rate of adherence to the dura was observed in patients with myelopathy caused by cervical OLF. Bilateral laminectomy and removal of the lesions, without extensive decompression of adjacent segments, provides an optimistic prognosis.

Dural ossification in ossification of the ligamentum flavum: a preliminary report

STUDY DESIGN

A retrospective review.

OBJECTIVE

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.

SUMMARY OF BACKGROUND DATA

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Surgical outcome of thoracic myelopathy secondary to ossification of ligamentum flavum

OBJECTIVES

Thoracic myelopathy secondary to OLF is a rare disease described almost exclusively in Japanese patients. Few series of OLF in South Korean subjects has previously been published. This study is to describe the clinical and radiologic aspects, as well as surgical outcomes in a group of South Korean patients.

METHODS

A retrospective study of 8 consecutive patients, including 4 men and 4 women (mean age, 55.6 years), was conducted from 2002 to 2005. Diagnosis in each case was established using CT. Magnetic resonance imaging was also performed in every case. All patients treated surgically and pathologic studies were performed. A comparison between the preoperative neurological status and the status at follow-up was done using Japanese Orthopaedic Association (JOA) scoring system.

RESULTS

Walking difficulties were the most common presenting complaint. A picture of spastic paraparesis associated with sphincter dysfunction was the most common finding on initial examination. In each case, CT provided sufficient information to establish a diagnosis of OLF, while magnetic resonance imaging was helpful for showing spinal cord involvement. In most of the patients, OLF was located in the lower thoracic spine (T10-T11). Decompressive laminectomy with excision of the OLF resulted in significant improvement in motor weakness and gait in 5 (2 excellent, 3 good) patients who had short duration and no hyperintense intramedullary lesion of spinal cord on MRI. All patients improved in their gait and spasticity, but 2 patients had persistent sensory deficit.

CONCLUSION

OLF is a rare cause of thoracic myelopathy. The frequency appears to have been rarely reported in South Korean subjects. CT with sagittal reconstructions and MRI are helpful for diagnosis and spinal cord involvement. When neurologic symptoms develop, decompressive laminectomy should be done immediately and the surgical outcome is generally good if hyperintense intramedullary signal changes of spinal cord have not yet developed.

Thoracic ossification of ligamentum flavum caused by skeletal fluorosis

Thoracic ossification of ligamentum flavum (OLF) caused by skeletal fluorosis is rare. Only six patients had been reported in the English literature. This study reports findings from the first clinical series of this disease. This was a retrospective study of patients with thoracic OLF due to skeletal fluorosis who underwent surgical management at the authors' hospital between 1993 and 2003. Diagnosis of skeletal fluorosis was made based on the epidemic history, clinical symptoms, radiographic findings, and urinalysis. En bloc laminectomy decompression of the involved thoracic levels was performed in all cases. Cervical open door decompression or lumbar laminectomy decompression was performed if relevant stenosis was present. Neurological status was evaluated preoperatively, at the third day postoperatively, and at the end point of follow-up using the Japanese Orthopaedic Association (JOA) scoring system of motor function of the lower extremities. A total of 23 cases were enrolled, 16 (69.6%) males and 7 (30.4%) females, age ranging from 42 to 72 years (mean 54.8 years). All patients came from a high-fluoride area, and 22 (95.7%) had dental fluorosis. Medical imaging showed OLF together with ossification of many ligaments and interosseous membranes, including interosseous membranes of the forearm (18/23 patients 78.3%), leg (14/23 patients 60.9%), and ribs (11/23 patients 47.8%). OLF was classified into five types based on MRI findings: localized (4/23 patients 17.4%), continued (12/23 patients 52.2%), skip (3/23 patients 13.0%), combining with anterior pressure (2/23 patients 8.7%), and combining with cervical and/or lumbar stenosis (2/23 patients, 8.7%). Urinalysis showed a markedly high urinary fluoride level in 14 of 23 patients (60.9%). Patients were followed up for an average duration of 4 years, 5 months. Paired t-test showed that the JOA score was slightly but nonsignificantly increased relative to preoperative measurement 3 days after surgery (P = 0.0829) and significantly increased at the end of follow-up (P = 0.0001). In conclusion, Fluorosis can cause ossification of thoracic ligamentum flavum, as well as other ligaments. Comparing with other OLF series, a larger number of spinal segments were involved. The diagnosis of skeletal fluorosis was made by the epidemic history, clinical symptom, imaging study findings, and urinalysis. En bloc laminectomy decompression was an effective method.

Spinal compression due to ossified yellow ligament: a short series of 5 patients and literature review

BACKGROUND

Ossification of ligamentum flavum in the thoracic region causing compressive myelopathy among middle-aged patients is a poorly described entity.

CASE DESCRIPTION

Five patients of Indian origin with OYL are described. Their clinical presentations, surgical options, and long-term outcome are presented. Radiologic and clinical follow-up of one of the patient is described over a span of 10 years.

CONCLUSIONS

Decompressive laminectomy and excision of the OYL is the commonly performed surgical procedure. A rapid neurologic improvement follows decompression. The persistent spasticity in certain patients is attributed to irreversible changes within the cord. The disease is thought to be progressive in nature. The prolonged follow-up of these patients suggests that the long-term prognosis is poor. Selective racial involvement and variable clinical presentations, with treatment options, are discussed.

Symptomatic ossification of the ligamentum flavum: a clinical series from the French Antilles

STUDY DESIGN

A series of 14 patients from the French Antilles treated for ossification of the ligamentum flavum (OLF).

OBJECTIVES

To describe the clinical and radiologic aspects, as well as disease course in a group of Caribbean patients. Also describe the use of sagittal computerized tomography (CT) reconstructions to distinguish OLF from calcification of the ligamenta flava.

SUMMARY OF BACKGROUND DATA

OLF is a rare disease described almost exclusively in Japanese patients. Only rarely are patients of African descent affected. No series of OLF in African American or African Caribbean subjects has previously been published.

METHODS

A retrospective study of 14 consecutive patients, including 7 men and 7 women (mean age, 66.8 years), was conducted from 1996 to 2003. Diagnosis in each case was established using CT. Magnetic resonance imaging was also performed in every case. For the 11 patients treated surgically, pathology studies were performed.

RESULTS

Walking difficulties were the most common presenting complaint. A picture of spastic paraparesis associated with sphincter dysfunction was the most common finding on initial examination. In each case, CT provided sufficient information to establish a diagnosis of OLF, while magnetic resonance imaging was helpful for showing spinal cord involvement. In most of the patients, OLF was located in the lower thoracic spine. Surgical decompression through a posterior approach resulted in regression of symptoms in all 11 patients treated surgically.

CONCLUSIONS

This study is the first reported series of OLF in a group of Caribbean patients. The disease appears to be underreported in the African Caribbean population. OLF can lead to debilitating thoracic myelopathy. Surgery is frequently indicated and achieves favorable results.

Contributing factors affecting the prognosis surgical outcome for thoracic OLF

The thoracic ossification of ligamentum flavum (OLF) is a disease that produces spastic paraparesis, and there are various factors that may affect the surgical outcome of thoracic OLF patients. The authors of this study treated 19 of these thoracic OLF patients from 1998 to 2002, and retrospectively reviewed the patients' age, sex, symptom duration, involved disease level, preoperative clinical features, neurological findings, radiological findings, the other combined spinal diseases and the surgical outcomes. There were excellent or good surgical outcomes in 16 patients, but 3 patients did not improve after thoracic OLF surgery: this included 1 patient, whose motor function worsened after decompressive thoracic OLF surgery. The favorable contributing factors of surgical outcome in thoracic OLF are a short preoperative symptom duration, single-level lesion, and unilateral lesion type on CT axial scan. On the contrary, the poor prognostic factors are beak type lesion and intramedullary signal changes on T(2)-weighted sagittal MRI. The complete preoperative evaluation including radiologic findings will provide valuable aid in presuming the surgical outcome for the thoracic OLF patients.

Radiculopathy due to ossification of the yellow ligament at the lower lumbar spine

STUDY DESIGN

A case report.

OBJECTIVES

To report a rare case of a 27-year-old female with ossification of yellow ligament at the lower lumbar spine presenting radiculopathy with a drop foot.

SUMMARY OF BACKGROUND DATA

The majority of cases of ossification of yellow ligament occur at the lower third of the thoracic or the thoracolumbar spine. There are only a few reports of ossification of yellow ligament in the lumbar spine and radiculopathy due to ossification of yellow ligament at L4-L5 and L5-S1 levels is very uncommon.

METHODS

A 27-year-old female with a prior fracture of posterior ring apophysis of L5 presented with leg pain and a drop foot. Magnetic resonance imaging demonstrated stenosis with compression of the cauda equina at the L4-L5 and L5-S1 levels.

RESULTS

Decompressive laminectomy of L5 and removal of the ossified yellow ligaments were performed. Histologic examination of en bloc specimen of ossification of yellow ligament revealed degenerative changes of the elastic fibers in the yellow ligament with adjacent chondrosis and ossification. The patient's severe leg pain disappeared completely, although the extent of the drop foot had not fully recovered at the final follow-up examination.

CONCLUSIONS

The mechanism of ossification of yellow ligament in the present case was unclear. The patient did not have any previous generalized disorders besides the history of a ring apophysial fracture or any family history of treatment for ossification of the posterior longitudinal ligament or ossification of yellow ligament. Therefore, localized mechanical stress might have influenced the development of ossification of yellow ligament at lower lumbar spine.

Thoracic myelopathy due to enlarged ossified yellow ligaments. Case report and review of the literature

Enlarged ossified yellow ligaments are a rare and poorly understood cause of thoracic myelopathy. The authors report the case of a patient in whom thoracic myelopathy was caused by enlarged ossified yellow ligaments.

Spinal cord compression caused by unusual location and extension of ossified ligamenta flava in a Caucasian male. A case report and literature review

STUDY DESIGN

A case report of a spinal cord compression caused by ossification of the ligamenta flava is presented together with a review of the literature.

OBJECTIVE

To present the diagnosis of ossification of the ligamenta flava in a Caucasian man with a proximal thoracic myelopathy.

SUMMARY OF BACKGROUND DATA

This case shows that the upper parts of the thoracic spine can be involved in ossification of the ligamenta flava, which never before has been reported in Caucasian individuals. Furthermore, it is advised that computed tomography scanning and magnetic resonance imaging be combined to provide an accurate diagnosis and proper preoperative evaluation of the bony changes, spinal cord, and compression of the spinal cord.

METHODS

A patient with a thoracic spinal cord compression caused by ossification of the ligamenta flava was treated surgically and made a good clinical recovery. Imaging studies, surgical findings, and results of histopathologic investigations were analyzed to substantiate the diagnosis.

RESULTS

The results of the surgical findings seemed to be in contrast with those of the imaging studies. This contrast was occasioned by the uncommon perioperative finding of a fusion of the completely ossified upper and lower parts of the involved adjacent ligamenta flava. Ossification of the ligamenta flava was diagnosed by histopathologic examination, which revealed endochondral ossification and lamellar bone formation without fragments of ligamenta flava.

CONCLUSION

Although rarely reported in whites, ossification of the ligamenta flava should be considered in all patients presenting with a spinal cord compression, even at high thoracic levels. The prognosis after decompressive surgery can be good, especially if intramedullary hyperintensities are absent on preoperatively performed T2-weighted magnetic resonance images.

Ossification of the ligament flavum

A total of 82 patients who underwent spinal computed tomographic scan, in an 8-month period at the King Khalid University Hospital, Riyadh, Saudi Arabia, were analyzed for age, sex, the presence/absence, site, and type of ossification of the ligamentum flavum (OLF) as well as associated diseases. The OLF was radiographically present (bilaterally or unilaterally) as linear (74.5%) or nodular types (25.5%). The linear type was especially seen at the inner aspects of the ligamentum flavum. OLF was present in 35.4% of patients, and was seen at single and multiple levels in 51% and 41% of them, respectively. OLF was identified in a total of 47 levels in the study group and was associated with other disease in the spine in 38 (81%) of these levels. In none of the patients was OLF the cause of myelopathy. The incidence of OLF and its pathogenesis and significance are discussed. This paper is the first report of OLF from the Middle East. OLF in this part of the world is usually asymptomatic.

Paraplegia due to ossification of ligamenta flava in X-linked hypophosphatemia. A case report

STUDY DESIGN

Spinal canal decompression at the most prominent of multiple posterior calcified thoracic lesions in a case of X-linked hypophosphatemia was undertaken for treatment and diagnosis purposes, as well as to assess possible nature of the pathophysiology underlying the presenting deficits.

OBJECTIVES

To discuss the clinical assessment diagnostic and treatment aspects of this rare coincidence of ossification of ligamenta flava in the patient with the skeletal deformities of X-linked hypophosphatemia.

SUMMARY OF BACKGROUND DATA

The patient with the stigmata and chemical findings of an X-linked hypophosphatemia presented with paraplegia and multiple calcified posterior spinal thoracic lesions. This was studied with magnetic resonance imaging and electrophysiologic studies of the spinal sensory pathways of the legs. These data constituted the preoperative information required to assess later results of surgical intervention.

METHODS

Presurgical clinical, imaging and electrophysiologic studies and laboratory and pathologic investigations of the surgical specimens.

RESULTS

Resolution of the paraplegia with walking and return to work in a physically demanding job for the last 4 or 5 years of postoperative follow-up after surgical decompression of the spinal cord only at the worst and highest of the effected spinal levels.

CONCLUSION

The coincidence of X-linked hypophosphatemia and ossification of ligamenta flava has been reported only in two or three cases in the literature. Removal of the offending ossifying lesion is known to result in resolution of the clinical deficits but similar lesions at other spinal levels are suspected of producing recurrences. The return of function and of the corresponding electrophysiologic correlates indicate a neurono-apractic nature of the neurologic symptoms.

Magnetic resonance imaging of tendon and ligament abnormalities: Part I. Spine and upper extremities

Magnetic resonance imaging (MRI) has proven to be an ideal technique for evaluating tendons and ligaments, which, because of their fibrous structure, have a low signal intensity on all sequences. Trauma and a wide variety of other conditions cause aberrations in the normal appearance of these structures, ranging from minor alterations in shape, size, appearance, and continuity to various changes in signal intensity within the tendon, tendon sheath, and ligament on different sequences. The purpose of this paper is to review MRI findings in patients with abnormalities of tendons and ligaments in the spine and upper extremities.