Far Lateral Approach for Microvascular Decompression of Ectatic Vertebral Artery-Associated Medullary Compression

Case Presentation: A 57-year-old male presented with progressive compressive bulbar symptoms, double vision, imbalance, and trouble swallowing food. Magnetic resonance angiography was obtained and demonstrated a dominant dilated right ventricular artery suggestive of ectasia which was compressing and effacing the medulla. Digital subtraction angiography redemonstrated the ectatic V4 segment of the vertebral artery which was large in caliber, traversed medially, and without evidence of any obvious aneurysm.

A right-sided far lateral approach was selected to perform microvascular decompression of the medulla. The right vertebral artery was found to be bulbous, tortuous, stiff, and atheromatous resulting in severe compression of the medulla. The vertebral artery was carefully separated and mobilized to decompress the medulla. The vertebral artery was mobilized laterally and left in place by placing Teflon felts between the artery and medulla.

The patient's postoperative course was complicated by the development of a pseudomeningocele which was definitively treated via placement of a right ventriculo-peritoneal shunt. At the 6-month follow-up, the patient reported that his balance, swallowing, and vision have improved.

Discussion: Medullary compression syndrome is a rare condition typically associated with an anomalous course of the posterior inferior cerebellar artery or the vertebral artery. Symptomatology of this condition can be extensive resulting in neurological deficits such as hemiparesis, ataxia, imbalance, dysphagia, palatal myoclonus, and cranial nerve dysfunction. Severe cases of medullary compression have been documented to result in quadriparesis and respiratory failure. The definitive treatment for medullary compression syndrome is microvascular decompression when there is clear radiographic evidence of compression in context of focal neurological deficits. Far-lateral and retrosigmoid approaches are most common and the surgical approach selection depends on the exact location of compression.

Conclusion: Symptomatic vascular compression of the medulla oblongata by vertebral artery is a rare phenomenon with only a few cases described in literature. Magnetic resonance imaging and digital subtraction angiography are important for both initial diagnosis and preoperative planning. Far lateral approach for microvascular decompression to obtain separation between vertebral artery and the medulla oblongata is a safe and an effective technique that results in resolution of brainstem dysfunction ([Figs. 1]–[3]).

Fig. 1 Preoperative magnetic resonance angiography brain T1 with contrast, axial view, demonstrating dominant right ectatic vertebral artery (arrow) resulting in significant mass effect on the underlying medulla.

Fig. 2 Preoperative digital subtraction angiography of the right vertebral artery. Anterior-posterior view demonstrates the V4 segment (arrow) to be ectatic, large caliber, and traversing medially, which caused the medullary compression.

Fig. 3 Postoperative magnetic resonance angiography brain T1 with contrast, axial view, redemonstrating right vertebral artery ectasia (arrow) with improved mass effect on the underlying medulla.

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Artikel online veröffentlicht:
15. Februar 2022