Myelopathy resulting from the atlantodental hypertrophic osteoarthritis accompanying the dens hypertrophy. Two case reports

Myelopathy resulting from degenerative atlantoaxial subluxation

PURPOSE

To present the clinical features and treatment strategy of degenerative atlantoaxial subluxation (DAAS).

METHODS

Patients with DAAS treated in our institution from 2003 to 2020 were retrospectively reviewed. We utilized the Japanese Orthopedic Association (JOA) scale to evaluate the neurologic status and distance of Ranawat et al. (DOR) to measure vertical migration.

RESULTS

We recruited 40 patients with > 2 years of follow-up and an average age of 62.3 ± 7.7 years. All the patients had myelopathy; only one patient had moderate trauma before exacerbation of symptoms, and the duration of symptoms was 34 ± 36 months. The most frequent radiological features were vertical migration of C1 (100%), sclerosis (100%), and narrowing of the atlantoaxial lateral mass articulations (100%). Two patients underwent transoral release combined with posterior reduction and fusion, and 38 patients underwent posterior reduction and fusion with C1 lateral mass screws-C2 pedicle screws and plate systems only. Forty cases (100%) achieved a solid atlantoaxial fusion, and 38 cases (95%) achieved anatomic atlantoaxial reduction. The JOA score increased from 9.3 ± 2.6 to 14.8 ± 2.1 (P < 0.01). DOR increased from 14.5 ± 2.5 to 17.8 ± 2.2 mm at the final follow-up (P < 0.01). Loosening of the locking caps was detected in one case, bony fusion was achieved, and harvest-site pain was reported in five patients.

CONCLUSION

DAAS differs from other types of AAS and presents with anterior subluxation combined with vertical subluxation arising from degenerative changes in the atlantoaxial joints. We recommend anatomic reduction as an optimal strategy for DAAS.

Cervical Myelopathy Caused by Posttraumatic Osteophytes Resulting From Long-Standing Neglected Posterior Atlanto-Occipital Dislocation More Than 30 years: A Case Report

Traumatic atlanto-occipital dislocation (AOD) is a rare but usually fatal injury. To our knowledge, no study has reported long-standing neglected posterior AOD more than 30 years in a patient who survived and later experienced cervical myelopathy.

Anterior endoscopically assisted bone grafting for iatrogenic distraction of odontoid fracture after percutaneous anterior screw fixation: A case report

RATIONALE

The complication of iatrogenic distraction of odontoid fracture after anterior screw fixation has not been reported in the literature. We treated the patient with endoscopically assisted bone grafting with good results. The new technique was not reported in the management of odontoid fracture or nonunion before.

PATIENT CONCERNS

A 22-year-old man presented with neck pain after a motorcycle crash. The cervical spine radiograph and computed tomographic scan demonstrated the base of dens displaced 2 mm anteriorly.

DIAGNOSES

Radiographic images showed a type II odontoid fracture.

INTERVENTIONS

The patient was treated by percutaneous anterior screw fixation. The postoperative radiograph and CT demonstrated an iatrogenic distraction of the odontoid with a gap of 6 mm.The follow-up radiograph did not show any sign of bone union 1 month and a half later. A revision surgery was given by anterior endoscopically assisted bone grafting. The patient was encouraged to sit out of bed immediately after the surgery with the protection of a soft cervical collar for 3 months.

OUTCOMES

No complications such as neural structures or vascular injuries were found. Bone union was achieved at the 1-year follow-up CT scans. Physical examination showed a full range of motion in the neck.

LESSONS

We reported a case of iatrogenic odontoid distraction that was managed by anterior endoscopically assisted bone grafting. It is a technically feasible and minimally invasive procedure.

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.

Cervical myelopathy secondary to atlas hypoplasia - reports of 3 adult cases -

There have been paucity of reports on atlas hypoplasia, and as a result this condition is not clearly defined, nor well understood. The authors reported three cases of atlas hypoplasia that were found in adults who presented with myelopathic symptoms. On radiographic examination, it was found that the anterior-posterior diameter of the atlas was remarkably narrower in all three cases in comparison with normal persons. The MRI in all three cases also revealed intramedullary high signal lesions at the levels where severe spinal cord compression was present. This led to our diagnosis of atlas hypoplasia causing myelopathy.

A safe screw trajectory for atlantoaxial transarticular fixation achieved using an aiming device

STUDY DESIGN

A retrospective evaluation and characterization of the trajectory of atlantoaxial transarticular screws inserted using an aiming device.

OBJECTIVES

To confirm that the screws were inserted through the safest trajectory, which is through the most dorsal and medial part of the isthmus of C2, and to characterize the trajectory on lateral radiograms by comparison with historical controls.

SUMMARY OF BACKGROUND DATA

Posterior atlantoaxial transarticular screw fixation entails the potential risk of vertebral artery (VA) injury, which may be lethal. Although much literature recommends that the screws should be inserted aiming at the anterior arch of C1, the authors considered that the safest screw path is via the most dorsal and medial part of the isthmus regardless of the C1 anterior arch, and have used an original aiming device to achieve this trajectory.

METHODS

Forty-three consecutive patients who submitted to atlantoaxial transarticular screw fixation using the aiming device were evaluated for screw position using computed tomography (CT) and lateral radiogram. The medialization index (the distance between the screw and the cortex of the spinal canal of C2 on axial CT) and the dorsalization index (the thickness of the bone remaining dorsal to the screw at the isthmus of C2 on sagittal reconstruction CT) were measured. Further, three parameters on the lateral radiograms of these patients were compared with those in the literature and those of our previous cases performed without the aiming device.

RESULTS

Neither VA injury nor violation of the spinal canal was encountered, although 12 high-riding VAs were included in this series. The mean medialization index was 0.21 mm, and the indexes of 86.3% of the screws were zero. The mean dorsalization index was 0.36 mm, and the indexes of 76.8% of the screws were zero. These results demonstrated that most of the screws were inserted as aimed, proving the usefulness of the aiming device. The trajectory of these screws on lateral radiograms was characterized by significantly less bone thickness dorsal to the screw at the isthmus compared with the two control groups. As a result, more screws were pointed above the anterior arch of C1.

CONCLUSIONS

The atlantoaxial transarticular screw was inserted safely as aimed by using the aiming device. The trajectory was characterized by less bone thickness dorsal to the screw on lateral radiogram, which should be a new intraoperative landmark for screw insertion, in place of the anterior arch of C1.

Reducción de las masas periodontoideas tras artrodesis posterior: revisión a propósito de 2 casos no vinculados a artritis reumatoide

Inflamatory periodontoid pannus is quite common in patients with rheumatoid arthritis. However, the occurrence of a pannus-like periodontoid mass that is unassociated with rheumatic inflammation is less frequent. Transoral surgery associated with a posterior stabilization has long been considered one of the most efficient methods to resolve the problem of instability in patients presenting neurological deficits secondary to the pannus. We present two cases of non rheumatic etiology, in which an occipito-cervical arthrodesis was used to resolve the proliferative lesion around the odontoid apophysis. Two women (67 and 60 years old respectively) presented symptoms of pain and neurological deterioration with an antecedent of possible past odontoid fracture in one case, and a previous large anterior cervical arthrodesis to correct spondylarthrosis in the other case. Both patient's neurological condition improved after placement of an arthrodesis through a posterior approach.

Hypertrophic dens resulting in cervical myelopathy: histologic features of the hypertrophic dens

STUDY DESIGN

A case report of a 43-year-old woman who had hypertrophic dens in the developmentally narrow atlas ring that resulted in cervical myelopathy.

OBJECTIVES

To present histologic findings of the hypertrophic dens, which was excised en block the transoral approach, and to discuss the pathogenesis of the hypertrophic change of the dens.

SUMMARY OF BACKGROUND DATA

Few cases have been reported of cervical myelopathy associated with hypertrophic dens, and there have been no previous reports describing the histologic features of hypertrophic dens.

METHODS

Clinical data were reviewed from the patient's chart, and histologic features of the hypertrophic dens were examined in the sagittally cut section.

RESULTS

After posterior decompression surgery, cervical myelopathy in the patient subsided. Myelopathy reappeared 4 years after surgery. Imaging studies showed osteoarthritis of the atlantodental joint, hypertrophic dens, and degeneration of the cruciate ligament. In the second surgery, transoral removal of the dens with posterior occipitocervical fusion was performed. Histologic studies showed thickening of the cortical bone of the anterior and cranial parts of the dens. The apical portion, which was the insertion portion of the ala ligaments, showed degenerative changes of tide marks.

CONCLUSION

Atlantoaxial instability and enthesopathy were probably the causes of the hypertrophic changes of the dens in this case.