Endovascular therapy, Endovascular surgery or Endovascular neurosurgery itself goes by an array of names: neuroendovascular surgery, neurointerventional surgery, interventional neuroradiology and endovascular surgical neuroradiology, or interventional neurology (IN), combines catheter-based techniques and imaging for the diagnosis and treatment of specific cerebral and spine conditions. Training is certified by the Committee on Advanced Subspecialty Training (CAST).
Doctors who perform endovascular surgery must have an excellent command of two different specialties: neurosurgery and radiology. Depending on their backgrounds, doctors who perform endovascular neurosurgery are called either endovascular neurosurgeons, interventional neuroradiologists, or interventional neurologists. Endovascular neurosurgeons trained originally as neurosurgeons and then received specialized training in radiology. Interventional neuroradiologists trained originally as radiologists and then received specialized training in neurosurgery. Interventional neurologists trained originally in neurology followed by training in endovascular neurosurgery.
Remarkable developments in the field of endovascular neurosurgery have been witnessed in the last decade. The success of endovascular therapy for ischemic stroke treatment is now irrefutable, making it an accepted standard of care. Endovascular treatment of cerebral aneurysms is no longer limited to primary coiling but now includes options such as stent or balloon assistance and flow diversion and applications utilizing neck reconstruction, intrasaccular, and bifurcation-specific devices. Balloons, liquid embolic agents, and flow-directed catheters have revolutionized the treatment of arteriovenous malformations and fistulae. The ongoing development of endovascular tools has led to novel and expanding approaches (for example, transvenous embolization of arteriovenous malformation and transradial access). With improved technology, transposterior communicating artery access and other endovascular strategies are being applied successfully across the anterior and posterior circulations and to lesions once deemed only surgically approachable. Yet, we would be remiss to attribute the successes of endovascular strategies only to the development of their tools. Improvements in both noninvasive and angiographic imaging (such as three-dimensional road map guidance) have provided a greater understanding of pathologic entities and allowed the pursuit of endovascular cures 1).
Doctors who perform endovascular surgery must have an excellent command of two different specialties: neurosurgery and radiology. Depending on their backgrounds, doctors who perform endovascular neurosurgery are called either endovascular neurosurgeons, interventional neuroradiologists or interventional neurologists. Endovascular neurosurgeons trained originally as neurosurgeons and then received specialized training in radiology. Interventional neuroradiologists trained originally as radiologists and then received specialized training in neurosurgery. Interventional neurologists trained originally in neurology followed by training in endovascular neurosurgery.
In fact, endovascular neurosurgery itself goes by an array of names: neuroendovascular surgery, neurointerventional surgery, interventional neuroradiology and endovascular surgical neuroradiology, for example.
see Endovascular Neurosurgery History.
Endovascular interventions have become an essential part of a neurosurgeon's practice.
The need for emergent neurosurgical procedures is very low among patients undergoing intracranial neuroendovascular procedures. Survival in such patients despite emergent neurosurgical procedures is quite low 2).
A study suggest potential gaps in the training of neurosurgery residents with regard to endovascular neurosurgery. In an era of minimally invasive therapies, changes in residency curricula may be needed to keep pace with the ever-changing field of neurosurgery 3)
The femoral artery is usually punctured below the inguinal ligament for neuroendovascular procedures with a 18-19 gauge needle.
To place the wire with Seldinger technique in the artery with removal of the percutaneous needle and the introduction of the sheath 4).
The sheath is removed at the end of the procedure, then manual compression should be performed for 10-20 minutes to achieve hemostasis.
This minimizes the risk of local and embolic complications.
Remove the sheath only when the Activated Partial Thromboplastin Time (aPTT) has returned to normal (< 36 secs) or when the Activated Clotting Time (ACT) is < 170.
see femoral arterial closure device.
Endovascular treatment by mechanical thrombectomy will be increasingly chosen as an adjunctive or alternative to intravenous thrombolysis. To apply this form of stroke treatment is associated with the challenge of optimal periinterventional treatment. The patient has to be identified, counselled, prepared, monitored, cardiovascularly stabilized, possibly sedated and ventilated, and postprocedurally treated in the optimal way. However, most aspects of periinterventional treatment have as yet not been clarified and require prospective research. Among these, the question of general anesthesia vs conscious sedation has received most attention and may be the most crucial one. Based on a great amount of retrospective data, it appears reasonable to start the intervention under conscious sedation of the non-intubated patient with standby measures for emergent intubation, until prospective randomized trials have clarified that issue. Periinterventional management will significantly affect the success of recanalization 5).
The expansion of endovascular techniques for intracranial aneurysms has led to a global decrease in vascular neurosurgery activity. This situation might impact neurosurgeons' level of expertise, even though they all might have to deal with this surgically challenging pathology, and pleads for the use of training and simulation programmes dedicated to neurovascular surgery 6).
● uncorrected (life-threatening) bleeding disorders
● relative contraindications:
○ poor renal function (due to iodine dye load): hemodialysis can be arranged in emergent situations; alternatively, the patient may be hydrated and monitored for a return to baseline creatinine
○ connective tissue disorder that predisposes to vessel dissection
○ severe allergy to iodine contrast: requires prior administration of “dye allergy prep”
○ Major atheroma of the aortic arch or plaque/atherosclerosis of great vessels (innominate, subclavian, common carotid artery) due to the high risk for thromboembolic complications
○ for spinal angiography: thoracic aortic aneurysm (relative)
A stable intracranial guide catheter position within the intracranial vasculature is critical for safe, successful endovascular treatment
Neuroendovascular treatment in Japan is increasing and the outcomes of such therapy are clinically acceptable. Details of each type of treatment will be investigated in sub-analyses of the database 7).
The risk of hemorrhage must be considered when using anticoagulation and antiplatelet therapy in patients requiring ventriculostomy. Interventionalists must not only work closely with neurosurgeons when it is anticipated that a ventriculostomy may be needed but also ensure that there is good communication with the neurosurgical team during the postprocedural period 8).