Ossification of the transverse atlantal ligament associated with fluorosis: a report of two cases and review of the literature

Ossification of the Transverse Ligament of the Atlas on CT: Frequency and Associated Findings

목적

경추 전산화단층촬영(cervical spine CT; 이하 C-spine CT)과 일반촬영을 이용하여 환추횡인대골화증(ossification of the transverse ligament of the atlas; 이하 OTLA)과 연관된 영상 소견에 대하여 알아보았다.

대상과 방법

11년간 3975명의 환자에게서 촬영한 5201개의 C-spine CT를 분석하여 OTLA의 유무를 확인하였고, 이를 대조군과 비교하여 그 빈도와 연관된 영상 소견의 통계학적 유의성을 확인하였다.

결과

3975명 중 45명에서 OTLA가 확인되었다(1.1%). 그 빈도는 나이에 따라 증가하는 소견을 보였으며(p < 0.005), 80세 이상인 환자의 12%에서 관찰되었다. 척수 공간(space available for spinal cord; 이하 SAC)은 OTLA 환자군에서 유의하게 작은 것으로 확인되었으며(p < 0.005), 전방환추후두막(anterior atlantooccipital membrane)-Barkow 인대 복합체의 광물질침착(mineralization), 황색인대골화증(ossification of ligamentum flavum), 경추후만증 또한 유의미한 양의 상관관계를 보였다(p < 0.005).

결론

OTLA는 환자의 나이, SAC 협소, 경추후만증, 다른 경추인대의 골화증과 연관되어 퇴행성 척추병증, 전신적인 골 과잉 상태, 혹은 기계적 스트레스나 불안정성에 관련이 있을 것으로 생각된다.

Ossification of the Cruciform Ligament of Atlas; a Rare Cause of Cervical Myelopathy: Case Report and Review of Literature

We present a case of cervical myelopathy secondary to ossification of the cruciform ligament (also known as cruciate ligament). This is a rare phenomenon that, to the best of our knowledge, has only been reported 16 times previously in literature. We have added a review of literature after our case presentation. We hope that by doing so, we may aid clinicians reach early diagnosis so as to be able to better manage this rare disease.

Cervical myelopathy due to ossification of the transverse atlantal ligament: a Caucasian case report operated on and literature analysis

One case of cervical myelopathy associated to ossification of transverse atlantal ligament (OTAL) and C1 posterior arch hypoplasia in a Caucasian adult female is reported. A 53-year-old female affected by cervical myelopathy was treated with C1 laminectomy and posterior arthrodesis. CT scan demonstrated that the distance between ossification of the ligament and anterior cortex of the posterior arch of atlas was 6,2mm leading to consistent space reduction for spinal cord at this level. Patient underwent spinal cord decompression and fixation with C1 poliaxial screws in lateral masses and two bilateral crossing C2 laminar screws with an improvement of neurological functions at 4-years follow-up. The association between OTAL and C1 hypoplasia was reported in very few cases. The treatment with C1 laminectomy without fusion is reported in medical literature with good clinical outcome. Our patient obtained a neurological improvement at midterm follow-up with spinal cord decompression and fusion.

Cervical myelopathy caused by anomalies at the level of atlas

STUDY DESIGN

Case report.

OBJECTIVE

To report a case of cervical myelopathy due to simultaneous anomalies at the level of atlas involving hypoplasia of the posterior arch of the atlas, partial ossification of the transverse atlantal ligament, and hypertrophy of the dens.

SUMMARY OF BACKGROUND DATA

Hypoplasia of the posterior arch of the atlas, ossification of the transverse atlantal ligament, and hypertrophy of the dens are all individually very rare clinical entities. We are not aware of previous reports describing the association of hypoplasia of the posterior arch of the atlas, partial ossification of the transverse atlantal ligament, and hypertrophy of the dens.

METHODS

The patient's medical history, physical examination, and radiographic evaluation are examined. Surgical treatment and clinical outcome are reported. In addition, available literature is also reviewed.

RESULTS

The patient's neurologic symptoms significantly improved after posterior decompressive surgery.

CONCLUSION

We believe this is the first case of cervical myelopathy caused by simultaneous anomalies at the level of atlas involving hypoplasia of the posterior arch of the atlas, partial ossification of the transverse atlantal ligament, and hypertrophy of the dens. Surgical intervention improved the neurologic impairment.

Characteristics of ossified lesions in the upper cervical spine associated with ossification of the posterior longitudinal ligament in the lower cervical spine

BACKGROUND

Ossified lesions of the upper cervical spine behind the dens may cause cervical myelopathy. We investigated the prevalence of ossified lesions in patients with ossification of the posterior longitudinal ligament in order to clarify the characteristics of these patients.

METHODS

Fifty-six consecutive patients with ossification of the posterior longitudinal ligament in the cervical spine were included in the study. Multidetector computed tomography images of the whole spine were made. Ossified lesions of the upper cervical spine were defined as ossified lesions behind the dens as seen on axial computed tomography images. The prevalence of ossified lesions at the first cervical level was analyzed. The clinical and radiographic parameters were compared between the patients with ossified lesions at the first cervical level and the patients without such lesions.

RESULTS

Fourteen patients (25%) had ossified lesions of the upper cervical spine. The continuous type of ossification of the posterior longitudinal ligament in the lower cervical spine was common and the segmental type was rare in this group as compared with the types of ossification in the group without ossified lesions at the first cervical level. The patients with first cervical level ossification more frequently had ossification of the posterior longitudinal ligament in the thoracic and/or lumbar spine, compared with the patients without upper cervical ossification. One patient had cervical myelopathy as a result of the upper cervical ossified lesion.

CONCLUSIONS

Computed tomography imaging demonstrated the presence of ossified lesions behind the dens in 25% of patients with subaxial ossification of the posterior longitudinal ligament. These upper cervical ossified lesions were commonly seen in patients with multiple-level ossification of the posterior longitudinal ligament. When upper cervical ossified lesions cause severe narrowing of the spinal canal, they should be considered a potential cause of cervical myelopathy.

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.

Thoracic myelopathy caused by ossification of ligamentum flavum of which fluorosis as an etiology factor

PURPOSE

To evaluate the clinical feature, operative method and prognosis of thoracic ossification of ligamentum flavum caused by skeletal fluorosis.

METHODS

All the patients with thoracic OLF, who underwent surgical management in the authors' hospital from 1993-2003, were retrospectively studied. The diagnosis of skeletal fluorosis was made by 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 existed. The neurological statuses were evaluated with the Japanese Orthopaedic Association (JOA) scoring system preoperatively and at the end point of follow up. Also, the recovery rate was calculated.

RESULTS

23 cases have been enrolled in this study. Imaging study findings showed all the cases have ossification of ligamentum flavum together with ossification of many other ligaments and interosseous membranes, i.e. interosseous membranes of the forearm in 18 of 23 (78.3%), of the leg in 14 of 23 (60.1%) and of the ribs in 11 of 23 (47.8%). Urinalysis showed markedly increased urinary fluoride in 14 of 23 patients (60.9%). All the patients were followed up from 12 months to 9 years and 3 months, with an average of 4 years and 5 months. The JOA score increased significantly at the end of follow up (P = 0.0001). The recovery rate was 51.83 +/- 32.36%. Multiple regression analysis revealed that the preoperative JOA score was an important predictor of surgical outcome (p = 0.0022, r = 0.60628). ANOVA analysis showed that patients with acute onset or too long duration had worse surgical result (P = 0.0003).

CONCLUSION

Fluorosis can cause ossification of thoracic ligamentum flavum, as well as other ligaments. En bloc laminectomy decompression was an effective method. Preoperative JOA score was the most important predictor of surgical outcome. Patients with acute onset or too long duration had worse surgical outcome.

Osteoma in the upper cervical spine with spinal cord compression

Osteoma is a common benign tumor. It occurs dominantly at the skull bone. Outside skull osteoma is rare, and primary intra-canal osteoma is extremely rare. To the author’s knowledge, only 14 cases of osteomas of the spine had been reported, in which only seven cases were in English literature. The authors reported two rare cases of intra-canal osteoma of the upper cervical spine with cord compression. Included are pertinent history, physical examination, rontgenographic evaluation before and after operation, surgical interventions, pathological study, and outcome. The available literature is also reviewed. On systemic examination and rontgenographic study, these two cases were found to have bone tumor in the upper cervical canal. Surgical interventions were performed, one with an en bloc excision, the other with a subtotal excision. The pathological study demonstrated a diagnosis of osteoma. After a follow-up with 20 and 15 months, the clinical symptoms of both cases significantly improved.

Ossification of the posterior atlantoaxial membrane and the transverse atlantal ligament

STUDY DESIGN

Case report.

OBJECTIVE

To report a case of ossification of the posterior atlantoaxial membrane (PAAM) and ossification of the transverse ligament of the atlas (TAL).

SUMMARY OF BACKGROUND DATA

Ossification of the PAAM and TAL are both very rare clinical entities. This is the first case involving ossification of both the PAAM and TAL with the development of cervical myelopathy.

METHODS

Patient's history, physical examination, radiographic evaluation, surgical treatment, and outcome are examined. Relevant literature is also reviewed.

RESULTS

The patient's neurological symptoms significantly improved after posterior decompressive surgery.

CONCLUSION

Ossification of various parts of the spinal ligament have been reported previously. Among them, ossification of both the PAAM and TAL has never been reported previously and is thus extremely rare. Surgical intervention improved the neurological impairment.