Original ArticleDural Tail Sign in the Resection of Ventral Foramen Magnum Meningiomas via a Far Lateral Approach: Surgical Implications
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 NeurosurgeryCitation 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).
Foramen magnum meningiomas: Surgical results and risks predicting poor outcomes based on a modified classification
2017, Journal of Neurosurgery
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.