Brainstem compression syndrome caused by vertebrobasilar dolichoectasia: microvascular repositioning technique

Abstract

Vertebrobasilar dolichoectasia (VBD) is an anatomic variant that consists of enlargement and dilatation, often associated with a tortuous and elongated vessel 1 . The anomaly is probably due to a marked thinning of the internal elastica lamina and media, most likely as a consequence of prolonged systemic arterial hypertension 2 . It accounts for approximately 3 to 5% of all cerebellopontine mass lesions. A variety of clinical syndromes have been related due to pulsatile compression by the aberrant vessel: cerebellar dysfunction, hydrocephalus, ischemic stroke, transient or permanent motor deficits, central sleep apnea, trigeminal neuralgia, as well as brain stem compression syndrome 1,3,4 . Microvascular decompression surgery was introduced in the 1960s and was initially used to treat trigeminal neuralgia, hemifacial spasm and glossopharyngeal neuralgia 5 . Lately, it was used to treat brainstem dysfunction caused by an ectatic vessel 1 . Nowadays, microvascular decompression with repositioning of the ectatic vessel is a new technique that has been used successfully.The purpose of this study is to report and discuss a rare case of brain stem compression syndrome caused by vertebrobasilar dolichoectasia successfully treated with microvascular decompression repositioning technique and documented by computed tomography angiography (CTA) and magnetic resonance imaging (MRI). CASEA 60-years old man with a past medical history of diabete mellitus type 2 sought neurological treatment after experiencing mild progressive disartria for eight months. He did not have other complaints. The patient's neurologial examination revealed, besides the speech abnormality, left side pyramidal syndrome with hiperreflexia and Babinski´s sign. All the other aspects of the neurological examination were intact. Imaging investigationMRI and CTA showed an elongated and tortuous vertebrobasilar artery that crossed the ventral aspect of the medulla oblongata causing mechanial compression at the left side (Figs 1 and 2). Surgical techniqueThe patient was placed in the prone oblique (park bench) position, and a left far lateral suboccipitoretromastoidea approach was performed with left vertebral artery exposure. The dura was opened, and cerebrospinal fluid was released at the cisterna magna to provide a capacious working environment.Arachnoid dissection revealed a large vascular structure, identified as the basilar dolichoectatic artery, dislocating and compressing the brain stem (medulla oblongata) in its left ventral region. As soon as the neurovascular conflicting area was

Research Progress on Vertebrobasilar Dolichoectasia

“…The mass effect of VBD can compress the nearby brainstem and cranial nerves, leading to symptoms such as weakness, dizziness, choking on water, cranial nerve damage, neurogenic hypertension, or pseudo space-occupying lesions within cranial fossa 4, 6, 29-31.…”

“…Although sometimes the mass effect of VBD can be very serious, the brainstem can gradually tolerate compression without showing obvious clinical symptoms. Nevertheless, some minor nerve damage can be detected that has important clinical significance 29. Passero et al found that the most common subclinical manifestations are extension of the blink reflex latency and changes in motor evoked potentials in limbs.…”

Hemifacial Spasm, Glossodynia, and Dolichoectasia of the Basilar Artery

“…19 A recent report described how the surgeon pulled the ectatic vessel away from the brain stem and fixed it to the nearby dura with unabsorbable nylon. 13 Satisfactory brain stem decompression was achieved, with subsequent symptom improvement. It should be noted that VBD with brain stem compression is an uncommon condition, and thus the reported surgical techniques and benefits claimed are merely anecdotal.…”

“…13 In the surgical approach to this condition, simply inserting a prosthesis between the vessel and the brainstem is insufficient to achieve decompression, because the size and stiffness of the dilated artery makes standard microsurgery difficult. Alternative techniques have been suggested.…”

“…7,11,12 Treatment by microvascular decompression has been advocated; 9 a new approach is to combine this with repositioning of the ectatic vessel. 13 Here I report a patient presenting with HFS and glossodynia in whom investigation revealed the presence of a grossly dolichoectatic basilar artery.…”