Journal of Craniovertebral Junction and Spine

CASE REPORT
Year
: 2021  |  Volume : 12  |  Issue : 4  |  Page : 440--444

Anterior cervical meningocele with craniovertebral junction instability – A case report and literature review


Ashutosh Kumar, Anant Mehrotra, Pawan Kumar Verma, Kuntal Kanti Das, Awadhesh Kumar Jaiswal, Sanjay Behari 
 Department of Neurosurgery, SGPGIMS, Lucknow, Uttar Pradesh, India

Correspondence Address:
Anant Mehrotra
Department of Neurosurgery, SGPGIMS, Lucknow, Uttar Pradesh
India

Abstract

Anterior meningocele involves herniation of meninges through an abnormal defect in the anterior vertebral column. The pathogenesis, natural history, and management strategy of anterior cervical meningocele (ACM) are uncertain. We report a case of ACM with high cervical instability in a case of neurofibromatosis 1. Unlike other reported cases, torticollis and instability due to ACM were the major concerns in this case. We aim to discuss the management strategy and surgical nuances of such cases.



How to cite this article:
Kumar A, Mehrotra A, Verma PK, Das KK, Jaiswal AK, Behari S. Anterior cervical meningocele with craniovertebral junction instability – A case report and literature review.J Craniovert Jun Spine 2021;12:440-444


How to cite this URL:
Kumar A, Mehrotra A, Verma PK, Das KK, Jaiswal AK, Behari S. Anterior cervical meningocele with craniovertebral junction instability – A case report and literature review. J Craniovert Jun Spine [serial online] 2021 [cited 2022 May 29 ];12:440-444
Available from: https://www.jcvjs.com/text.asp?2021/12/4/440/332219


Full Text



 Introduction



An anterior meningocele involves herniation of meninges through an abnormal defect in the anterior vertebral column while neural elements remain intact. Anterior cervical meningocele (ACM) affecting craniovertebral junction has never been reported previously. Its occurrence in the high cervical region posed torticollis and craniovertebral junction instability as the major concerns. We aim to discuss the management strategy and surgical nuances of such cases.

 Case Report



A 19-year-old female had presented with torticollis since childhood, progressive vision loss in both eyes for 4 months, and cerebellar symptoms for 3 months. The fundus examination study was suggestive of early papilledema. Bilateral cerebellar signs were positive. There were multiple café au lait spots and freckles over the trunk. There were no symptoms or signs attributable to compression by the sac.

Imaging

The magnetic resonance imaging (MRI) brain revealed thickened bilateral optic nerves and left cerebellar pilocytic astrocytoma with proximal hydrocephalus [Figure 1]. The meninges were seen herniating anteriorly into the retropharyngeal space at C2, C3, and C4 vertebral level. No neural elements were seen within the sac [Figure 2]a and [Figure 2]b. On computed tomography (CT) cervical spine with three-dimensional reconstruction, the right lateral mass and part of the body of C3 and C4 vertebrae were absent. The right C2 pars and pedicle were also deficient [Figure 3]a and [Figure 3]b. The posterior elements of C2 and C3 were fused. Dynamic X-rays of the cervical spine revealed abnormal mobility at the C3-C4 level along with atlanto-axial dislocation [Figure 3]c and [Figure 3]d.{Figure 1}{Figure 2}{Figure 3}

Management

Under general anesthesia, intubation with a laryngoscope was performed. No compression due to the ACM was seen that could make intubation difficult. Care was taken to completely immobilize the neck while the patient was turned to the prone position. The head was stabilized in the sugita frame in a neutral position. Following midline suboccipital craniectomy, the dura was seen bulging between the C1 and the C2 posterior elements. The sac reduced in size on opening the dura. Following tumor excision, the C1-C2 joint was exposed. The right C2 nerve root was cut that showed egress of cerebrospinal fluid (CSF), causing further decompression of the thecal sac. The right C2 pars and pedicle were hypoplastic with a tilt to the right side. Bilateral C1, C3, and C4 lateral mass screws were placed and fixed with a rod. An external lumbar drain was placed intraoperatively as a preventive measure against postoperative CSF leak.

Postoperative recovery

The postoperative scan showed total excision of the tumor with correction of torticollis. She was planned for chemotherapy for optic nerve glioma. The external lumber drain was removed on postoperative day 5. [Figure 4] shows postoperative CT cervical spine showing the fixation. A follow-up MRI cervical spine was done in the 18th month. The anterior meningocele was of the same size as in the preoperative scan [Figure 2]c. The patient continues to be asymptomatic for ACM at 18 months of follow-up.{Figure 4}

 Discussion



Anterior meningocele is most commonly seen in the sacral region, followed by thoracic and lower cervical levels. To the best of our knowledge, eight cases of anterior or anterolateral cervical meningocele have been reported. This is the second case where C2 was also involved, leading to torticollis and high cervical instability. The pathogenesis, natural history, and management strategy of ACM are uncertain. [Table 1] summarizes the clinical presentation, management, and outcome in the reported cases.{Table 1}

Neurofibromatosis is associated with mesodermal dysplasia and dural ectasia. The mesodermal dysplasia in NF1 causes vertebral body defect with subsequent anterior herniation of the dysplastic meninges leading to anterior meningocele. We concur with this most acceptable hypothesis. It explains the occurrence of the large boney defect involving three levels and the vertebral bodies seen in this young patient. Furthermore, neurofibromatosis 1 was the underlying syndrome in seven out of the nine cases of spontaneous ACM.[1],[2],[3],[4],[5],[6],[7],[8] Another hypothesis is the progressive erosion of widened intervertebral foramina in neurofibromatosis. This is supported by the findings of the authors who reported multiple anterior and anterolateral meningoceles. Other possibilities such as cystic degeneration of neurofibroma, trauma, or elongated nerve sheaths are less likely. ACM is nondysraphic as against the posterior cervical meningoceles.

Only two cases, including the present case, had ACM involving CVJ. Both these patients were young and had torticollis since birth. All other patients were having subaxial cervical spine ACM and their average age was 49 years (range 40–59 years). Neck pain was the most common presenting complaint. Airway compromise and dysphagia as a result of mass effect could be a major complication due to the sac. Despite a large sac, our patient had none of these symptoms. The intubation was smooth with no airway compromise. Only three out of nine cases of cervical meningocele had presented with dysphagia and dysphonia.[3],[5],[7] In all other cases, ACM was an incidental finding.

There are two aspects of ACM management-ACM sac repair and instability due to boney defect. Despite the theoretical possibility of ACM causing immense morbidity by its location, it remains essentially benign. Only one in nine patients needed intervention for ACM sac for severe compressive symptoms.[7] Similar to this case, two other authors reported nonprogression of sac size in the follow-up. It is to be noted that there is no neural component in the ACM (unlike myelomeningocele) or any associated neurological deficits due to the sac. In this given scenario, any attempt to repair it at this site would do more harm than good. Insertion of lumbo-peritoneal shunt has been reported to allow decompression of anterior meningocele. As there were no symptoms and no progression of the sac, we preferred to avoid a hardware placement. The cervical spine instability due to boney defect must be addressed. Due care should be taken during intubation and positioning of these patients.

 Conclusion



Congenital ACM is pathognomic of NF1, occurring as a consequence of mesodermal dysplasia and dural ectasia. It is a rare cause of craniovertebral junction instability. Given a benign course, management is conservative. Surgical intervention is indicated for the secondary instability or rarely for compressive symptoms due to the sac.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the legal guardian has given his consent for images and other clinical information to be reported in the journal. The guardian understands that names and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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