Disappearance of degenerative, non-inflammatory, retro-odontoid pseudotumor following posterior C1-C2 fixation: case series and review of the literature

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.

Dynamic paraspinal muscle impingement causing acute hemiplegia after C1 posterior arch laminectomy: A case report

RATIONALE

Acute neurological deficits following spinal surgery commonly result from epidural hematoma, surgical trauma, vascular compromise, and graft or hardware impingement, with the cause identified by magnetic resonance imaging (MRI). We present a rare case of dynamic paraspinal muscle impingement after C1 posterior arch laminectomy, which was diagnosed by myelography, with no significant findings on MRI.

PATIENT CONCERNS

An 81-year-old, severely obese male, was referred to our department for the treatment of vertebral disease of the lumbar spine. The patient presented with bilateral weakness and numbness of the upper extremities and gait disturbances. Based on MRI, a diagnosis of retro-odontoid pseudotumor was made, and C1 posterior arch laminectomy, in combination with C4 partial laminectomy and C5 to C6 laminoplasty, was performed. On postoperative day 3, the patient's neurological status deteriorated, with right upper extremity and right lower extremity weakness increasing with neck extension. Although there was no evidence of epidural hematoma formation on MRI, obstruction of the flow of contrast medium by an external posterior compression in neck extension at the level of C1 was identified by myelography. Revision surgery was performed and local muscle swelling at the surgical site identified with no hematoma formation. Occiput to C3 fixation, with instrumentation, was performed.

OUTCOMES

Muscle strength of the right upper extremity and lower extremities recovered postsurgery, and the patient has continued to improve function 3 years after surgery, with no further neurological episodes.

LESSONS

Dynamic paraspinal muscle impingement following C1 laminectomy in a muscular man was diagnosed by myelography, with no significant findings on standard MRI.

CONCLUSION

The possibility of dynamic paraspinal muscle impingement should be considered in patients developing acute, progressive, neurological deficits after posterior cervical decompression, with myelography being the imaging method of choice for diagnosis.

Complications in Craniovertebral Junction Instrumentation: Hardware Removal Can Be Associated with Long-Lasting Stability. Personal Experience

BACKGROUND

The causes of craniovertebral junction (CVJ) instabilities include trauma, rheumatological diseases, tumors, infections, congenital malformations, and degenerative disease processes; these complex pathologies often require CVJ instrumentation. Hardware complications were analyzed in a personal series of 48 treated patients. In light of the analysis of very unusual radiological and clinical findings, the authors tried to better investigate the related mechanisms and to reach possible useful conclusions.

METHODS

In a series of 48 patients who underwent CVJ instrumentation and fusion procedures in our Institution, we describe three cases of hardware failure, due to: (1) infection; (2) radio- and chemotherapy; and (3) incorrect surgical procedure.

RESULTS

1. A stable bone CVJ fusion can occur after instrumentation removal for infection, since this removal can enhance bone fusion mechanisms; 2. Radio- and chemotherapy can cause hardware failure due to interference with local bone metabolism; 3. Although old-fashioned, wiring techniques still deserve consideration, mostly in CVJ re-do surgery after screwing technique failures; nevertheless, although the procedure is simple, safe, and effective, care must be taken in the preparation of the cranial holes in order to avoid sliding complications of the U-shaped rods.

CONCLUSIONS

CVJ instrumentations provide reasonably good mechanical stabilization with a high rate of bony fusion. Complications, such as dislocation or rupture of the fixation system, screw loosening, dural fistula, neural or vascular damage, and wound infection, are relatively infrequent. Knowledge and prevention of these complications is fundamental to improve surgical results and outcomes.

Exploration for reliable radiographic assessment method for hinge-like hypermobility at atlanto-occipital joint

PURPOSE

Hinge-like hyper-mobility is occasionally observed at the atlanto-occipital (O-C1) joint. However, it has not been clear if this kind of hinge-like hyper-mobility at the O-C1 joint should be regarded as "pathologic", or referred to as "instability". To solve this issue, we aimed to establish a reliable radiographic assessment method for this specific type of O-C1 instability and figure out the "standard value" for the range of motion (ROM) of the O-C1 joint.

METHODS

To figure out the standard range of the O-C1 angle, we acquired magnetic resonance imaging (MRI) sagittal views of the cervical spine for 157 healthy volunteers [average: 37.4 year-old (yo)] without spine diseases, at neutral, maximum flexion and maximum extension positions.

RESULTS

The average value (AVE) for ROM of O-C1 angle was 9.91°. The standard value for ROM of O-C1 angle was calculated as 0°-21°. There was no statistically significant gender difference. We also found that the older population (≧ 40 yo) significantly had a larger ROM of O-C1 angle (AVE: 11.72°) compared to the younger population (< 40 yo) (AVE: 8.99°).

CONCLUSIONS

We consider that hinge-like instability at O-C1 joint, which cannot be assessed by measuring Powers ratio, can be assessed by measuring the range of O-C1 angles using dynamic-MRI. Evaluation of O-C1 instability is important especially when we perform surgical treatment for diseases with upper cervical instability (such as retro-odontoid pseudotumor). We consider that the current study provides important information in such a case.

Restrictions of cervical flexion after laminoplasty increase in the mechanical stress at the occipitocervical junction in non-rheumatoid arthritis patients

Increased range of motion (ROM) at O-C2 after cervical laminoplasty is thought to be a compensatory change due to loss of cervical ROM after surgery. Retro-odontoid pseudotumor in non-RA patients is also caused by loss of ROM at C2-C7 causing mechanical stress on upper cervical spine. The aim of this study was to measure the occipitocervical alignment before and after cervical laminoplasty, and examine the factors associated with postoperative retro-odontoid soft tissue (ROST) enlargement. The study comprised 72 non-RA patients (51 males and 21 females, mean age 65.2years) who underwent cervical laminoplasty. The cervical angles (O-C1, O-C2, C1-C2, and C2-C7) were measured and ROST thickness was evaluated on mid-sagittal T1-weighted MRI before surgery and 2years after surgery. Correlations between radiographic changes and postoperative ROST enlargement were examined. The results shows that postoperative ROM and kyphotic angle in flexion position at O-C2 significantly increased, and postoperative ROM and kyphotic angle in flexion position at C2-C7 significantly decreased compared with preoperative values. On stepwise multiple regression analysis, age (beta=0.273, p<0.01) and restriction of cervical flexion postoperatively (beta=0.235, p<0.01) were independently associated with ROST enlargement. In conclusion, occipitocervical ROM increased and C2-C7 ROM, especially C2-C7 kyphotic angle in flexion, reduced after cervical laminoplasty. The ROST enlargement was associated with reduction in cervical flexion. These results indicate that preservation of cervical ROM, especially kyphotic angle in flexion, after cervical laminoplasty contribute to reduction of mechanical stress at the occipitocervical junction.

Retro-odontoid mass without atlantoaxial instability causing cervical myelopathy: a case report of transdural surgical resection

INTRODUCTION

Retro-odontoid mass rarely occur in patients with noninflammatory retro-odontoid lesions without atlantoaxial instability. We describe a rare case of retro-odontoid mass without atlantoaxial instability operated on by a transdural approach.

CASE PRESENTATION

The patient was an 83-year-old man who presented with a retro-odontoid mass causing symptomatic cervical myelopathy. Preoperative magnetic resonance imaging (MRI) revealed that the mass was severely compressing the spinal cord. We operated on it via a C1 laminectomy and performed tumor resection by a transdural approach. Pathological findings from the operative specimen confirmed the diagnosis; histopathological examination revealed that the mass contained fibrinoid material, and collagenous tissue with myxoid changes, but no granulation or a granulomatous lesion. Postoperative MRI confirmed spinal cord decompression. The patient's symptoms were alleviated, and he has not had a recurrence or cervical instability in the 7 years since his surgery.

DISCUSSION

We successfully used a transdural approach in the present case and have observed no recurrence for 7 years postoperatively. C1 laminectomy is reportedly beneficial, especially for elderly patients, given the risk of other surgical options using an anterior transoral approach or posterior fusion. However, most tumors do not attenuate after C1 laminectomy alone; hence, we think that tumor resection by the transdural approach is one effective method to perform enucleation of the tumor after C1 laminectomy.

Cervical myelopathy involving os odontoideum and retro-odontoid cyst treated with Harms C1-C2 arthrodesis

An episode of acute decompensation of cervical myelopathy occurred after an injury without fracture of an os odontoideum associated with a compressive retro-odontoid cyst. The 51-year-old female patient presented Fränkel C, Nurick grade 4 neurological status and pyramid syndrome. The initial MRI demonstrated an intramedullary T2 hyperintense signal in the context of spinal cord narrowing. The retro-odontoid cyst demonstrates atlantoaxial instability related to the os odontoideum. Harms C1-C2 arthrodesis without laminectomy was performed and the cyst disappeared completely. Spinal cord decompression was thus obtained on the MRI taken 3 months later. Neurological recovery was complete and continued at 1 year.

Complex cervical spondylotic myelopathy: a report of two cases and literature review

STUDY DESIGN

A report of two cases with complex cervical spondylotic myelopathy (CSM) and review of the literature.

OBJECTIVE

To describe two unique patients with complex CSM due to simultaneous anomalies as anteroposterior compressions of the spinal cord in both upper and lower cervical spine, caused by hypertrophic transverse ligament of atlas (TLA), dysplasia of the posterior arch of atlas, disc herniation, hypertrophic ligamentum flavum and osteophytes.

METHODS

We present such two cases with clinical, imageological presentations, and describe the surgical procedure, to which both patients responded favorably.

RESULTS

The neurological functions of both patients gradually improved according to the JOA scores and VAS scores in preoperative clumsiness and gait disturbance during the mean follow-up period lasted for 18 months. The latest plain radiographs and computed tomography (CT) revealed good fusion without instrumental failure and magnetic resonance imaging (MRI) showed good decompression of C1-7 spinal cord of both patients. Both patients are progressively followed-up.

CONCLUSION

Posterior surgical approach as C1-7 laminectomy with fixations or occipital-cervical fusions may obtain better reconstructions of the cervical spine and good neurological recovery for the patients with complex CSM we present. However, the incidence and ethnic predisposition for the patients with complex CSM are still unclear.

Idiopathic hypertrophic craniocervical pachymeningitis

PURPOSE

Hypertrophic craniocervical pachymeningitis (HCP) is a rare disease causing chronic inflammatory hypertrophy of the cranial and spinal dura mater. To increase awareness of this condition, we report the details of a case here.

METHODS

We reviewed the case of a 78-year-old man presenting with a rare case of HCP and summarized the clinical features, laboratory evaluations and treatment of the case.

RESULTS

In this case, the HCP involved the intracranial dura and high cervical regions, manifesting as lower cranial nerve palsies, headache, and neck pain, developing over 7 months. Magnetic resonance imaging revealed thickening of the dura in the craniocervical region with peripheral enhancement. Steroid therapy was commenced and the symptoms improved rapidly.

CONCLUSIONS

HCP can be diagnosed by MRI and laboratory investigations. In this case corticosteroid treatment was effective, although care must be taken when slowly reducing the dose. This case highlights HCP as a cause of progressive cerebellomedullar and cervical spinal cord symptoms.