Arteriovenous Malformation Resection
Updated On: July 23, 2026
Anesthetic Approaches
Perfusion pressure breakthrough - brain around the nidus has been chronically underperfused and sits maximally dilated with autoregulation lost. Take the shunt away and it meets a normal pressure it can no longer control, so it swells and bleeds. This is the defining hazard of the case.
Pressure target flips at resection - a controlled, slightly reduced pressure while the feeders are being taken, then a deliberately lower one once the nidus is out. Get the actual number from the surgeon before the last feeder goes, not after the brain starts to swell.
Massive sudden loss - a high-flow nidus can empty a circulation faster than almost any other craniotomy. Two large-bore lines and an arterial line before incision, blood checked into the room, and transfusion triggers taken from current institutional practice rather than memory.
Recently embolized patient - many arrive days after a staged embolization, with a partly thrombosed nidus and a fresh groin puncture. Ask what was occluded and when, because the flow you are managing is not the flow on the original angiogram.
Ruptured presentation - an acute bleed brings raised intracranial pressure, blood in the ventricles, a depressed conscious level and a full stomach. That is not the elective case: secure the airway without a pressure surge and treat the intracranial pressure first.
Induction without a surge - the malformation stays pressurized until it is out, and the hypertensive response to laryngoscopy or to pinning is a classic moment for a rebleed. Give the scalp block before the pins go in and have vasoactive drugs drawn up.
Position follows the nidus - supine with the head turned for anterior lesions, lateral for occipital ones, modified prone or semi-sitting for the posterior fossa and thalamus. Confirm it early, because it decides line placement, access to the patient and airway security.
Air entrainment when head-up - the deep posterior and thalamic lesions are done semi-sitting, which puts open venous channels above the heart. Watch end-tidal carbon dioxide for a sudden fall, and agree in advance what the surgeon does when it happens.
Relaxation for a deep lesion - a lumbar drain or an osmotic agent is often requested so the nidus can be reached without retraction. Settle before draping whether a drain is going in and who controls it, because over-drainage shifts the brain itself.
Evoked potentials decide the relaxant - motor and sensory potentials are commonly run during resection near eloquent cortex, and motor responses will not survive a maintained block. Agree it before induction, then keep the anesthetic steady so a change means surgery.
Intraoperative angiography - a femoral sheath is placed and runs are taken during and after the resection to prove the nidus has gone. Position arms and lines to leave the groin reachable, and expect imaging over the patient with long periods of enforced stillness.
Seizures on both sides - the malformation commonly presents with them and a cortical resection adds more. Find out what anticonvulsant is running and what is planned intraoperatively, because a load given fast will drop the pressure you are working to hold.
Emergence is a decision - a clean complete resection may be woken for an examination, while a large, staged or difficult one stays intubated and pressure-controlled. Hand over the agreed upper pressure limit and the neurological baseline, because the bleeding risk peaks afterwards.
Tucked Arms (general considerations): Consider a second IV – once the procedure has started, it's going to be VERY difficult to handle IV issues – especially if your only IV has problems. Ensure the IV is running and monitors are still functioning after tucking the patient's arms.
High Blood Loss (general considerations): Type and cross, CBC, and CMP should be done prior to the procedure. Consider having an A-line, blood tubing, and extra push-lines. Depending on the fragility of the patient, you may want to have blood in the room and available.
Prone Position (general considerations): Maintain cervical neutrality. Keep IV's out of the antecubital space. The patient's arms are typically flexed, which will kink the IV. Eye protection should be used as the prone position heightens the risk of corneal abrasion and/or traction on the globe (which can result in blindness). Check the patient's eyes/ears/nose regularly throughout the case to ensure they are free of pressure. Positioning of the leads is typically high on the posterior and posterolateral back (somewhere free of pressure and out of surgical borders). Keep your connections and tubing where you'll have fast access.
Lateral position (general considerations): If an ETT has been placed, make sure ETT is secure with extra tape. Unhook anesthesia circuit while turning lateral and be especially careful to keep patient's head neutral and aligned with body to avoid neck injury. Once lateral, use pillows/blankets/foam headrest to keep the patient's head in neutral position. The most common nerve injury for orthopedic lateral procedures are neurapraxias of the brachial plexus. These are motor and/or sensory loss for 6-8 weeks due to pressure on the contralateral (dependent) axilla. To prevent this, place an axillary roll under the patient (caudad to the axilla, on the rib cage, and NOT in the axilla). Check routinely to make sure the axillary roll does not migrate into the axilla. If the non-dependent arm is placed on a board, check padding and reposition regularly to avoid radial nerve compression. If a bean bag is employed, check the hard edges to ensure that unnecessary pressure isn't being put on soft tissues. Pad all dependent bony prominences such as the fibular head (to prevent peroneal nerve injury), and place pillows between the knees and ankles (to prevent saphenous nerve injury). If anterior hip supports are in place, ensure they are properly padded or neuropraxias and/or occlusions of large blood vessels may result.
Long procedure (general considerations): Procedures anticipated to last longer than 2 hours generally require a urinary catheter. Also, consider checking lines and positioning regularly as the risks of infiltration and nerve damage are increased with procedure time. Consider an IV fluid warmer and a forced air warmer to keep the patient euthermic.
Mayfield Pins (general considerations): The Mayfield skull clamp is a 3-pin head immobilization device. Mayfield pins are usually applied after induction. Unless a scalp block has been administered, application of the pins is EXTREMELY stimulating/painful. Extra sedation (commonly propofol 50-100 mg) should be given prior to the pins being applied to avoid the hemodynamic response expected with extreme pain.
Fluoroscopy / Xray (general considerations): Have lead aprons and thyroid shields available. Alternatively, distancing yourself 3 to 6 feet will reduce scatter radiation to 0.1% to 0.025% respectively. Occupational maximum exposure to radiation should be limited to a maximum average of 20 Sv (joules per kilogram - otherwise known as the Sievert/Sv) per year over a 5 year period. Limits should never exceed 50 Sv in a single year.
Arterial line (general considerations): Preoperatively check pulses to gauge the best side to attempt the A-line. Perform an Allen test to ensure adequate blood flow. Have the A-line equipment set up and ready in the room.
MEPs (general considerations): Most commonly, anything above the cauda equina (T1/T2) will be MEP and SSEP monitored in spinal cases. Long-term paralytics are normally contraindicated. Short term paralytics (eg succinylcholine) may be used for intubation. Some surgeons will prefer complete TIVA (eg. a common combination is propofol 25-150 mcg/kg/min, remifentanil 0.125-1.0 mcg/kg/min), while others are fine with 1/2 MAC of gas and a propofol drip. Ask the surgeon. Additional equipment needed: bite block, BIS monitor (if using TIVA).
High Blood Loss RISK (general considerations): Though most of these cases don't result in a high blood loss, there is a high blood loss RISK. Type and cross, CBC, and CMP should be done prior to the procedure. Consider having an A-line, blood tubing, and extra IV push-lines. Depending on the fragility of the patient, you may want to have blood in the room and available.
Bispectral Index Scale (BIS) monitor (general considerations): The recommended values under general anesthesia are 40-65. Values of 65-85 are recommended for sedation.
An arteriovenous malformation is a tangle of vessels, the nidus, in which arteries feed veins directly with no capillary bed in between. The vessel walls are thin and lack a muscular layer, so they neither autoregulate nor respond normally to carbon dioxide. Blood at arterial pressure runs straight into veins, flow through the lesion is high, and the surrounding brain is chronically short-changed by the steal; those neighboring vessels sit maximally dilated and have given up their own autoregulation to compensate. That adapted state is the whole problem. Presentation is hemorrhage, seizures, headache or a progressive deficit, with an untreated rupture risk of roughly 2 to 4% a year. Complete microsurgical excision removes that risk, but it also removes the shunt the surrounding brain has spent years adapting to.
Staged embolization first - most moderate and large malformations over 3 cm are partly embolized in the catheter lab days to weeks beforehand to cut flow through the nidus and make resection survivable.
Positioning and navigation - the patient is placed so the craniotomy site is uppermost and parallel to the floor, the head fixed in a radiolucent pin headrest, and image guidance registered to the scan.
Craniotomy - a scalp flap and bone flap are centered over the nidus; small or deep-seated lesions instead get a small stereotactic craniotomy of a few centimetres, planned off fiducials or a frame.
Circumferential dissection - working under the microscope, the surgeon dissects around the outside of the nidus and occludes feeding arteries in sequence, never entering the malformation itself.
Draining vein last - the main draining vein is only taken once the arterial supply is controlled; sacrificing it early engorges the nidus and turns a controlled dissection into torrential bleeding.
Angiographic confirmation - runs through a femoral sheath during and at the end of the case confirm the nidus is gone, and any residual is hunted down before the dura is closed.
Closure - hemostasis is tested at a normal or slightly raised pressure, the dura closed and the flap replaced, often with a ventricular or lumbar drain left in place.
Some resections near eloquent cortex are done awake with direct cortical mapping; brain relaxation is harder without controlled ventilation, so confirm early whether that is the plan.