Elsevier

World Neurosurgery

Volume 84, Issue 5, November 2015, Pages 1402-1411
World Neurosurgery

Original Article
Dural Tail Sign in the Resection of Ventral Foramen Magnum Meningiomas via a Far Lateral Approach: Surgical Implications

https://doi.org/10.1016/j.wneu.2015.06.062Get rights and content

Objective

To investigate the implications of dural tail sign (DTS) in the tailored far lateral approach for resection of ventral foramen magnum meningiomas (FMMs).

Methods

Clinical data for 16 patients treated surgically for ventral FMMs over 5 years were reviewed retrospectively.

Results

The DTS was positive in 11 cases (68.8%) and negative in 5 cases (31.2%). The most frequent form was a single cranial tail (7 of 11), followed by multiple tails consisting of a cranial tail and a caudal tail (3 of 11), and multiple tails composed of a cranial tail and a contralateral tail (1 of 11). The retrocondylar approach was carried out in 5 cases without DTS characterized by a narrow dural attachment and a partial transcondylar approach in 11 cases with DTS featuring a broad and hypervascular dural attachment. Drilling ranged from approximately one fifth to one third of the condyle with reference to the DTS form and tumor size. Total tumor removal was achieved in 16 patients. Postoperative complications were encountered in 25% of patients, predominantly associated with cranial nerve impairment. Follow-up ranging from 8 to 56 months (mean 24.4 months) showed no tumor recurrence.

Conclusions

In addition to tumor dural attachment and tumor size, we propose that DTS should be considered as another factor in planning the surgical approach for ventral FMMs. Differentiation between a positive and negative DTS plays a role in the neurosurgical planning of ventral FMMs. Bone removal is warranted in tumors with DTS, particularly the multiple form with contralateral tails, to facilitate the surgical procedure and achieve a more radical resection.

Introduction

Foramen magnum meningiomas (FMMs) have been defined as tumors arising anteriorly from the inferior third of the clivus to the superior edge of the C2 body, laterally from the jugular tubercle to the C2 laminae, and posteriorly from the anterior border of the occipital squama to the spinal process of C2 2, 4, 7, 8, 17. Despite the development of microsurgery and skull base techniques, FMMs located in such an accessible and eloquent area of the brain remain a technical challenge for neurosurgeons. The far lateral approach has been widely considered as the first choice for removal of intradural ventral and ventral-lateral FMMs 7, 8, 13. Nevertheless, debate still exists regarding what amount of the lateral wall of the foramen magnum (FM) should be removed for ventral FMMs 1, 2, 4, 14, 17.

The resection of dura invaded by tumor is essential for complete removal of a meningioma. Many investigators attribute meningioma recurrence to the fact that the extent of resection, especially for the tumor-associated dura, is not sufficient 5, 11, 12, 15, 18. The pathological changes in the dura around the tumor can be interpreted by evaluating the dural tail sign (DTS) on magnetic resonance imaging (MRI) studies, which appears as linear meningeal thickening adjacent to an intracranial pathology or a spinal lesion on contrast-enhanced T1-weighted MRI. The prevalence of a dural tail in meningiomas ranges from 52% to 78% 9, 10, 16. However, there is still no consensus available on the precise histopathological characteristics of DTS. Tumor invasion, connective tissue expansion, angiogenesis, dilated vessels, and reactive hyperplasia have been suggested as the possible causes of the DTS. Nevertheless, an increasing number of studies have demonstrated a high incidence of a tumor-invaded dural tail, supporting the fact that the dural tail should be resected as much as possible in meningioma surgery to reduce recurrence 11, 12, 15.

As shown in the published literatures, the site of dural attachment and tumoral size are the primary factors that may indicate the extent of bone resection in the surgical treatment of FMMs 1, 2, 4, 7, 8, 17. Herein, we describe the role of DTS in the resection of ventral FMMs with the aim of presenting a full analysis of the MRI features of the tumor, thereby designing a more tailored surgical approach to accomplish ideal exposure and achieve maximum tumor resection with minimum morbidity.

Section snippets

Patient Population

From September 2009 to September 2014, 16 patients with ventral FMMs were surgically treated in our institute. All the patients were operated on for the first time for the tumors, with no history of previous radiotherapy. The medical records were reviewed with respect to the clinical, radiological, and surgical aspects of these tumors, as well as the outcome after mid-term follow-up. This study fulfilled all the requirements of the Declaration of Helsinki and was approved by the institutional

Clinical Data

Thirteen patients were women and 3 were men; they ranged in age from 42 to 67 years (mean 57 years). The most common symptom and sign was cervicooccipital pain in 13 patients, hemiparesis and hemihypesthesia in 5 patients (muscle strength grade III–IV), hypoglossal palsy in 2 patients, and paresis of the glossopharyngeal and vagus nerve in 1 patient associated with dysphagia and hoarseness. Dysfunction of a sphincter was not observed in any patient. The demographic data, the clinical and

Necessity of Dealing with the Dural Tail in Surgery for Ventral FMMs

On the basis of a relatively large number of cases, 3 histopathological studies are currently available regarding invasion of tumor cells in the dural tail of intracranial meningiomas 11, 12, 15. The incidence of a tumor-invaded dural tail was 64% (20 of 31), 61.1% (22 of 36), and 88.3% (158 of 179) in each of these studies, respectively. Given the high incidence of a tumor-invaded dural tail, it should be mandatory to resect the dural tail as much as possible in meningioma surgery. The extent

Conclusions

Our study demonstrated that the presence of DTS as well as its direction of extension have implications on the necessity and amount of bone removal for ventral FMMs. We propose that a partial transcondylar approach should be reserved for selected ventral FFMs including small tumors regardless of DTS and large tumors with DTS. Meanwhile, more extensive bone removal is dictated by the presence of a horizontal dural tail extending contralateral to the surgical approach. The value of this finding

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Cited by (4)

  • Disposal of Occipital Condyle in Far Lateral Approach for Ventrolateral Foramen Magnum Meningiomas

    2016, World Neurosurgery
    Citation Excerpt :

    The far lateral approach has become widely accepted as an essential technique for lesions involving the foramen magnum.1-3 However, controversy still exists regarding the optimal management of ventral or ventrolateral lesions.4-9 There is still no consensus available in the literature in terms of the drilling of the occipital condyle in surgery for ventrolateral foramen magnum meningiomas (FMMs).

Bo Wu and Shang-Hang Shen have equally contributed to the article and are considered as co-first authors.

Conflict of interest statement: The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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