Case report. Atlantoaxial synovial cyst causing isolated unilateral hypoglossal nerve paralysis

Hypoglossal Nerve Neuropathies-Analysis of Causes and Anatomical Background

The hypoglossal nerve is the last, and often neglected, cranial nerve. It is mainly responsible for motor innervation of the tongue and therefore the process of chewing and articulation. However, tumors, aneurysms, dissections, trauma, and various iatrogenic factors such as complications after surgeries, radiotherapy, or airway management can result in dysfunction. Correct differential diagnosis and suitable treatment require a thorough knowledge of the anatomical background of the region. This review presents the broad spectrum of hypoglossal neuropathies, paying particular attention to these with a compressive background. As many of these etiologies are not common and can be easily overlooked without prior preparation, it is important to have a comprehensive understanding of the special relations and characteristic traits of these medical conditions, as well as the most common concomitant disorders and morphological traits, influencing the clinical image. Due to the diverse etiology of hypoglossal neuropathies, specialists from many different medical branches might expect to encounter patients presenting such symptoms.

Management of rare atlantoaxial synovial cyst case with extension to the cerebellopontine angle: illustrative case

BACKGROUND

Synovial cysts are a common finding in degenerative spine disease, most frequently involving the facet joints of the lumbar spine. Synovial cysts are less common in the cervical spine and rarely involve the atlantoaxial junction.

OBSERVATIONS

In this case report, the authors detail a unique presentation of a left atlantoaxial synovial cyst with large intracranial extension into the cerebellopontine angle causing progressive cranial nerve palsies resulting in tinnitus, vertigo, diminished hearing, gait imbalance, left trigeminal hypesthesia, left facial weakness, and dysarthria. The patient underwent a retromastoid craniectomy for resection of the synovial cyst, resulting in improvement and resolution of symptoms. Follow-up occurred at 6 weeks, 3 months, and 5 months postoperatively without recurrence on imaging.

LESSONS

The authors describe acute and long-term management of a unique presentation of an atlantoaxial synovial cyst including retromastoid craniectomy, intervals for follow-up for recurrence, and possible treatment options in cases of recurrence. A systematic literature review was also performed to explore all reported cases of craniocervical junction synovial cysts and subsequent surgical management.

Recognition of Prodromal Hypoglossal Nerve Palsy Presenting with Neck Pain as Primary Complaint: Findings from a Rare Case Report in Direct Access Physiotherapy during the COVID-19 Pandemic

Neck pain (NP) is the second most common musculoskeletal disorder. Spinal cysts (SCs) are cystic dilatations of the synovial sheaths in joints and tendons. SCs are extremely rare in the cervical spine. Typically, patients are unaware of having an SC due to its asymptomatic nature; however, when cervical SC extends, its volume could compress the surrounding structures, such as the hypoglossal nerve. Isolated hypoglossal nerve palsy (HNP) is very rare and typically presents with unilateral atrophy of the musculature of the tongue and contralateral tongue deviation. Often, patients with HNP also report occipital/neck pain. A 75-year-old man with occipital/neck pain as a primary complaint. Although difficult to observe because of the filtering facepiece two mask, difficulties in articulation and sialorrhea during the interview were noticed. These latter were cues to consider CN examination that revealed CN XII palsy. This prompted a referral for further examination that revealed an SC compressing the right hypoglossal canal. The patient was not considered a surgical candidate and was managed conservatively. This case report outlines the relevant findings relating to the triage of a rare isolated hypoglossal nerve palsy from the physiotherapist's perspective within a complex setting because of the COVID-19 pandemic. Although referred with a diagnosis of cervical radiculopathy, our case highlights that skilled physiotherapists may play a fundamental role in both the recognition and, when applicable, subsequent novel management of a non-musculoskeletal presentation.

Unusual Stroke-Like Symptoms in a Patient With Generalized Osteoarthritis

A usual presenting symptom for osteoarthritis (OA) is pain. However, OA of the spine can present as isolated nerve palsy. We present a case of isolated hypoglossal nerve palsy secondary to chronic OA of the cervical spine. A 68-year-old female presented to the emergency department with stroke-like symptoms of three-day duration. History revealed heaviness of the tongue with dysphagia to solid foods, tongue deviation to the right, and slurred speech over the past year. On examination, she had severe OA of the distal and proximal interphalangeal joints. Various imaging modalities revealed isolated right unilateral hypoglossal nerve paralysis secondary to craniocervical junction degenerative disease from C1-occipital osteophyte and juxta-articular atlantooccipital (AO) synovial cyst. This case is unique as evidenced by various imaging modalities which consistently revealed advanced OA of our patient’s AO joint leading to osteophytic and juxta-articular cyst development causing unilateral hypoglossal nerve palsy.  

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.

Atlantooccipital Synovial Cyst with Isolated Hypoglossal Nerve Palsy: Case Report of Nonfusion Surgical Approach and Review of Literature

BACKGROUND

Isolated hypoglossal nerve palsy caused by an atlantooccipital synovial cyst is a rare lesion, with fewer than 5 cases reported in the literature.

CASE DESCRIPTION

Our patient presented with acute hypoglossal nerve dysfunction. Our differential included neoplasm, trauma, stroke, multiple sclerosis, or other inflammatory/infectious etiology. Imaging revealed a peripherally enhancing, extradural focus in the left premedullary cistern, most likely consistent with a synovial cyst.

CONCLUSIONS

A left suboccipital craniectomy was performed in the region of the left hypoglossal canal, in which a cystic structure was noted at the occipital condyle and C1 vertebral junction. The nerve was adequately decompressed via aspiration of the cyst. Postoperatively, the patient substantially improved. Although rare, synovial cysts must be included in the differential diagnosis of atlantooccipital lesions.

Is Hypoglossal Nerve Palsy Caused by Craniocervical Junction Degenerative Disease an Underrecognized Entity?

Isolated hypoglossal nerve palsy is uncommon, and underlying craniocervical junction degenerative disease has rarely been reported as an underlying cause. To improve understanding of this entity, we present a retrospective series of 18 patients with hypoglossal palsy in whom twelfth cranial nerve compression within the premedullary cistern or hypoglossal canal, or both, was found secondary to craniocervical junction juxta-articular cysts, retro-odontoid fibrous pseudotumors, and osteophytes. The imaging techniques and characteristic craniocervical junction degenerative disease lesion imaging findings presented here might help clinicians interpreting hypoglossal palsy imaging studies avoid perceptual and interpretive errors commonly found in the present series.

An inferior alveolar intraneural cyst: a case example and an anatomical explanation to support the articular theory within cranial nerves

The authors describe the case of an intraneural ganglion cyst involving a cranial nerve (V3), which was found to have a joint connection in support of an articular origin within the cranial nerves. An inferior alveolar intraneural cyst was incidentally discovered on a plain radiograph prior to edentulation. It was resected from within the mandibular canal with no joint connection perceived at surgery. Histologically, the cyst was confirmed to be an intraneural ganglion cyst. Reinterpretation of the preoperative CT scan showed the cyst arising from the temporomandibular joint. This case is consistent with the articular (synovial) theory of intraneural ganglion cysts. An anatomical explanation and potential joint connection are provided for this case as well as several other cases of intraneural cysts in the literature, and thus unifying cranial nerve involvement with accepted concepts of intraneural ganglion cyst formation and propagation.

Atlantoaxial Synovial Cyst Associated with Instability in a Chihuahua

Objective. To describe an atlantoaxial degenerative cyst associated with instability.Animal. Chihuahua, male, 5 years old.Methods. Ever since colliding with a large dog two years prior to presentation, the dog suffered recurrent episodes of intractable cervical pain. Over time, the pain attacks increased in frequency and intensity. On presentation, pain was clinically localized to the high cervical region. No neurological deficits were observed. CT and MRI revealed an atlantoaxial degenerative articular cyst associated with instability, causing cervicomedullary compressive myelopathy. On MRI the cyst appeared hypointense in T1W and hyperintense in T2-weighted sequences, with rim enhancement. The dog was treated surgically by cyst fenestration and ventral stabilization using a 1.5 mm Butterfly Locking plate and cancellous bone graft placed within the atlantoaxial joint after cartilage removal. Histological examination of a sample of the cyst wall confirmed a degenerative articular cyst. The dog recovered uneventfully after surgery and remained pain free throughout the 2-year followup.Conclusion. Atlantoaxial degenerative articular cyst associated with instability is a rare finding in dogs.Clinical Relevance. The presence of an atlantoaxial degenerative articular cyst appears not to worsen the prognosis of instability treatment. Atlantoaxial fusion and cyst fenestration may provide good long-term results.