Physical Address

304 North Cardinal St.
Dorchester Center, MA 02124

Extracranial-Intracranial High-Flow Bypass


The authors wish to thank Takanori Fukushima for work on the previous edition’s version of this chapter.

Additional videos for this topic are available online at https://expertconsult.inkling.com/ .

Indications

  • Despite advances in endovascular neurosurgery, cerebral bypass operations remain essential components in the management of giant aneurysms and some skull base tumors involving the carotid artery. Sacrifice of the internal carotid artery (ICA), either inadvertently or in a planned fashion, can be associated with substantial mortality (5%) and morbidity (15%).

  • Iatrogenic or traumatic ICA injury with symptomatic dissection or pseudoaneurysm that cannot be managed endovascularly can be considered for high-flow bypass and ICA occlusion.

Contraindications

  • This procedure is relatively contraindicated in elderly patients, patients with serious medical comorbidities, and patients in poor neurologic condition.

Planning and positioning

Types of High-Flow Carotid Bypass

Fig. 33.1, Fukushima bypass type 1.

  • Type 1 bypass is indicated for the management of intracavernous giant aneurysms and cavernous carotid stenosis and for radical resection of invasive meningioma or malignant tumors in this location.

    Fig. 33.2, Fukushima bypass type 2.

  • Type 2 bypass is indicated for the repair of infratemporal or high cervical aneurysms, dissecting aneurysms, and stenosis and radical resection of infratemporal meningiomas or glomus tumors.

    Fig. 33.3, Fukushima bypass type 3.

  • Type 3 bypass is used for management of proximal carotid aneurysms and intracavernous aneurysms.

    Fig. 33.4, Fukushima bypass type 4.

  • Type 4 bypass is used for the management of basilar artery giant aneurysms.

  • Preoperative evaluation includes a complete neurologic examination and assessments for visual function, respiratory status, cardiovascular status, diabetes mellitus, and gastrointestinal function. Preoperative routine laboratory values (complete blood count, coagulation profile, electrolytes, chemistry, and basic metabolic profile), chest x-ray, and electrocardiogram are essential.

  • In addition to the standard neurologic examinations of computed tomography (CT), magnetic resonance imaging (MRI), or magnetic resonance angiography, a four-vessel catheter angiogram is essential for neuroradiologic evaluation of the vascular process. Frequently, a balloon occlusion test is indicated for assessment of cross flow or collateral circulation capacity.

  • The patient is given a dose of preoperative antibiotics and dexamethasone (10 to 20 mg intravenously) before the skin incision. Brain relaxation is achieved with mannitol (25 to 50 g intravenously), furosemide (Lasix; 20 to 40 mg intravenously), and hyperventilation. When a tight brain is expected, a lumbar catheter may be inserted for continuous cerebrospinal fluid drainage intraoperatively and postoperatively. For temporary arterial occlusion during a difficult anastomosis procedure, a moderate dose of intravenous heparin (2000 to 4000 U), moderate hypothermia (33° C to 35° C), and barbiturate burst suppression pharmacologic brain protection may be used.

Positioning

Fig. 33.5, The patient is placed in the supine position with the head supported on an ear, nose, and throat (ENT) silicone pillow. The head is rotated to the other side for easy access to the frontotemporal craniotomy and to the submandibular cervical region. Most of the time, a three-pin skull clamp is avoided to facilitate opening of the cervical carotid artery and saphenous vein passage through submandibular, pterygoid, and subzygomatic areas to the subtemporal area. After the scalp and muscle layer are elevated, the head can be fixated securely with multiple blunt scalp hooks and blue silicone rubber bands anteriorly and posteriorly.

  • Generally, the patient’s upper torso is elevated 15 degrees, and the operating table is positioned at 15 degrees reverse Trendelenburg position to maintain the head above the level of the heart.

Procedure

You're Reading a Preview

Become a Clinical Tree membership for Full access and enjoy Unlimited articles

Become membership

If you are a member. Log in here

Related Posts