Resolution of Cystic Deterioration of the C1-2 Articulation with Posterior Fusion: Treatment Implications for Asymptomatic Patients

Os odontoideum associated with a retro-odontoid cyst treated with posterior C1-C3 fixation: A case report and literature review

Background

Os odontoideum is a rare abnormality of the upper cervical spine, and os odontoideum associated with a retro-odontoid cyst has been described as a marker of local instability.

Case description

This paper reports a case of a 52-year-old female patient who was diagnosed with os odontoideum associated with a retro-odontoid cyst. The patient underwent posterior C1-C3 fixation without surgical removal of the cyst. Magnetic resonance imaging (MRI) two days later revealed that the retro-odontoid cyst was still present and that there were no significant changes to it when compared with the preoperative MRI.

Conclusion

Retro-odontoid cysts associated with unstable os odontoideum can lead to symptomatic spinal cord compression. Posterior C1-C3 fixation can restore atlantoaxial stability by allowing the gradual resorption of the cyst and ensuring spinal cord decompression. Fixation can also avoid the surgical risk associated with a high-riding vertebral artery.

Synovial Cyst of the Atlantoaxial Joint Removed through a Posterior Intradural Approach

Introduction. Synovial cysts rarely develop in the atlantoaxial joint. We report a case of posterior C1-2 laminectomy for a synovial cyst of the atlantoaxial joint which passed through the dorsal dura and put pressure on the cervical spinal cord. Case Presentation. A 62-year-old man with rapid progression of pain and weakness in the left upper extremity presented to our hospital. A cervical spine X-ray showed left C5-6 and C6-7 stenoses. A cervical magnetic resonance imaging showed an intradural extramedullary cystic lesion on the right side of the ventral cervical spinal cord at the C1-2 level and severe compression of the cervical spinal cord. Because a cyst was partially enhancing, a tumor lesion was not identifiable. Due to severe spinal cord compression, we performed intradural cyst removal via a posterior intradural approach with C1-2 laminectomy and left-sided C5-6 and C6-7 foraminotomies. One year after surgery, the cyst did not recur, and atlantoaxial instability did not appear. Discussion. A compressive lesion on the cervical spinal cord was not identified preoperatively as a synovial cyst. However, intraoperative and pathological findings suggested that the compressive lesion can be a synovial cyst which passed through the dorsal dura. The surgical treatment strategy for a synovial cyst of the atlantoaxial joint is controversial due to factors, such as the presence of atlantoaxial instability, level of cyst causing compression of the cervical spinal cord, severity of myelopathy, and cyst location. In the present study, the cervical spinal cord was highly compressed and the cyst was located on the right side of the cervical spinal cord; we chose cyst removal through a posterior intradural approach with C1-2 laminectomy.

Treatment of pediatric unstable os odontoideum with adjacent degenerative cyst: case presentation and literature review

Degenerative cysts associated with an unstable os odontoideum in pediatric patients are uncommon lesions. Reported treatments of such lesions have varied and yielded mixed results with the optimal surgical strategy remaining unclear. The authors report the clinical and surgical outcome of a 13-year-old patient presenting with degenerative cyst adjacent to an abnormal os odontoideum motion segment. The patient was asymptomatic from this lesion which was an incidental finding while undergoing workup for atypical headaches. Clinical and radiologic findings, operative details, and postoperative outcome are described. The patient was successfully treated with posterior cervical fusion without direct cyst decompression. Complete resolution of the cyst was demonstrated on magnetic resonance imaging at 6 months. Computed tomography 8 months postoperatively showed solid bony fusion and normal alignment. Regarding treatment goals in pediatric patients with os odontoideum degenerative cysts, the current case and literature review supports posterior instrumented fusion without direct surgical cyst resection.

Cervical myelopathy caused by ventrally located atlanto-axial synovial cysts: An open quest for the safest and most effective surgical management. Case series and systematic review of the literature

OF BACKGROUND DATA

Despite a good understanding of the natural history of spinal synovial cysts (SCs), a widespread agreement regarding their optimal management is still lacking. This is particularly true for SCs occurring at the C1-C2 level, which are rare, but oftentimes lead to a rapidly evolving cervical myelopathy.

METHODS

We report a series of 4 patients (M:F ratio=1:1; mean age 63.5 years) presenting with progressive cervical myelopathy secondary to ventrally located C1-C2 SCs. All patients underwent a postero-lateral facet-sparing intradural approach with total excision of the SCs. Functional status was assessed pre- and postoperatively with Nurick scale and the modified Japanese Orthopaedic association grading. Furthermore we conducted a systematic review, following PRISMA guidelines of pertinent literature to contextualize the options for surgical management of such lesions.

RESULTS

Complete excision of the SCs was confirmed radiologically and on histological analysis. All measures of functional status improved post-operatively, and no cyst recurrence or need for instrumented fusion were noted during follow up (range from 22 to 88 months).

CONCLUSION

Our experience suggests that the facet-sparing intradural approach provides excellent clinical outcomes without causing any C1-C2 instability. This is in keeping with the take home message emerging from our literature review, which confirms that treatment should aim at radical resection of SCs while minimizing the risk of postoperative instability.

Transnasal and Transoral Approaches to Atlantoaxial Synovial Cysts: Report of 3 Cases and Review of the Literature

BACKGROUND

Synovial cysts are cystic masses lined with pseudostratified columnar cells and containing clear or xanthochromic fluid. Although they are commonly encountered in the lumbar spine, synovial cysts infrequently occur in the cervical spine and rarely involve the odontoid process. The causes of synovial cysts of the odontoid process are unknown, but growth of synovial rests, proliferation of multipotent mesenchymal cells, atlantoaxial instability, and trauma are thought to play a role.

CASE DESCRIPTION

We present 3 cases of atlantoaxial cysts with the associated radiographic features, surgical management, and clinical outcomes. No patient had rheumatoid arthritis. In all cases, preoperative differential diagnosis included neoplastic pathologic changes. Two patients underwent odontoidectomy through either an endonasal or a transoral approach, followed by posterior occipitocervical fusion. The third patient underwent an endoscopic transsphenoidal approach for cyst decompression.

CONCLUSIONS

Tissue diagnosis is important in confirming pathologic analysis because synovial cysts have radiographic characteristics similar to those of a wide variety of neoplasms of the craniovertebral junction.

Lateral Atlantoaxial Osteoarthritis: A Narrative Literature Review

Lateral atlantoaxial osteoarthritis (AAOA), or C1-C2 lateral mass arthritis (LMA), is an unfamiliar degenerative cervical disease with a clinical presentation that markedly differs from subaxial spondylosis. The prevalence of LMA in the nonsurgical outpatient setting is 4%. Risk factors include age and occupation. The typical patient is between 50 and 90 years old, presents with upper cervical or occipital pain, has limited rotation, and has pain provocation during passive rotation to the affected side. Pain stems from degeneration of the lateral C1-C2 articulation and may be referred or radicular, through the greater occipital nerve. Although there is no consensus on diagnostic work-up, the disease is classically seen on the open-mouth odontoid radiograph. Computerized tomography, magnetic resonance imaging, bone scan, and diagnostic injections are also useful. Initial treatment is conservative, and upwards of two-thirds of LMA patients obtain lasting relief with noninvasive measures and injections. In patients with severe, recalcitrant pain, limited C1-C2 fusion offers satisfactory and reliable relief. The goals of this review article are to provide a synthesis of the literature on LMA, to offer a treatment approach to LMA, and to identify problems with the current state of knowledge on LMA.

Synovial cysts of the spine: long-term follow-up after surgical treatment of 141 cases in a single-center series and comprehensive literature review of 2900 degenerative spinal cysts

OBJECTIVE Synovial cysts of the spine are rare lesions, predominantly arising in the lumbar region. Despite their generally benign behavior, they can cause severe symptoms due to compression of neural structures in the spinal canal. Treatment strategies are still a matter of discussion. The authors performed a single-center survey and literature search focusing on long-term results after minimally invasive surgery. METHODS A total of 141 consecutive patients treated for synovial cysts of the lumbar spine between 1997 and 2014 in the authors' department were analyzed. Medical reports with regard to signs and symptoms, operative findings, complications, and short-term outcome were reviewed. Assessment of long-term outcome was performed with a standardized telephone questionnaire based on the Oswestry Disability Index (ODI). Furthermore, patients were questioned about persisting pain, symptoms, and further operative procedures, if any. Subjective satisfaction was classified as excellent, good, fair, or poor based on the Macnab classification. RESULTS The approach most often used for synovial cyst treatment was partial hemilaminectomy in 70%; hemilaminectomy was necessary in 27%. At short-term follow-up, the presence of severe and moderate leg pain had decreased from 93% to 5%. The presence of low-back pain decreased from 90% to 5%. Rates of motor and sensory deficits were reduced from 40% to 14% and from 45% to 6%, respectively. The follow-up rate was 58%, and the mean follow-up period was 9.3 years. Both leg pain and low-back pain were still absent in 78%. Outcome based on the Macnab classification was excellent in 80%, good in 14%, fair in 1%, and poor in 5%. According to the ODI, 78% of patients had no or only minimal disability, 16% had moderate disability, and 6% had severe disability at the time of follow-up. In this cohort, 7% needed surgery due to cyst recurrence, and 9% required a delayed stabilization procedure after the initial operation. CONCLUSIONS Surgical treatment with resection of the cyst provides favorable results in outcome. Excellent or good outcome persisting for a long-term follow-up period can be achieved in the vast majority of cases. Complication rates are low despite an increased risk of dural injury. With facet-sparing techniques, the stability of the segment can be preserved, and resection of spinal synovial cysts does not necessarily require segmental fusion.