LITT (Laser Interstitial Thermal Therapy) Procedures
Anesthetic Protocol for LITT (Laser Interstitial Thermal Therapy) Procedures
Minimally invasive procedure in which heat is delivered through a fiber optic probe to a given tissue producing coagulative necrosis.
Can be used for cytoreduction of tumors in liver, bone, pancreatic, brain and spine.
With MRI thermal monitoring, LITT can be used for neurosurgical procedures in the treatment of metastatic and primary CNS tumors, radiation necrosis, pain disorders and refractory epilepsy.
Lower morbidity and neurocognitive complications, shorter hospital stays, reduced costs and a potential improvement in the survival of patients with primary and metastatic brain tumors are possible with this technology.
Contraindications: Large and irregular lesions, lesions adjacent to major blood vessels, acute intracranial hemorrhage, artifacts adjacent to lesions
Perioperative and anesthetic considerations
Complete history and neurologic exam paying close attention to pre-operative neurologic deficits. These cases are not solo provider friendly. Safety mandates 2 providers because of transport issues, multiple patient moves and off site location with minimal resources for back up.
Patient positioning can be supine, lateral decubitus, sitting or prone. Here at OU our experience has been that patients are usually supine and occasionally lateral decubitus.
Surgical time is typically 180-360 minutes although can be longer with larger lesions.
Standard ASA monitors with generally 2 peripheral IV’s, an arterial line and Foley catheter (NO TEMP Foley IN MRI!!).
Patient may need additional dexamethasone, mannitol and/or levetiracetam prophylaxis. Additionally, nicardipine may be need to keep systolic BP < 140 systolic during probe placement.
Type of anesthesia is generally a combination of inhalational and TIVA with propofol and/or remifentanil with muscle relaxation.
It’s important to minimize the possibility of patient movement during the actual treatment phase to prevent probe dislodgement. Sometimes periods of apnea are needed during treatment phase as well
Here at OU, most often the frame, burr holes and fiber placement are placed under GA in the main OR. TIVA or combo inhalation/ propofol infusion can be used.
After frame/fiber placement, the patient is transported to the MRI suite with GA maintained with a propofol infusion. Have a travel bucket prepared with extra meds and supplies (propofol, muscle relaxants, vasopressors, vasodilators, LMA ETC.)
The main OR should remain open and sterile in case patient needs to urgently return for an intracranial hemorrhage until officially released by neurosurgeon.
In MRI holding, the patient is moved to an MRI table, monitors are connected to the MRI compatible monitors (ECG, NIBP, invasive BP, SaO2 and End tidal CO2, temp).
Place ear plugs in patient for protection.
While this is going on the second anesthesia provider can be setting up the MRI compatible anesthesia machine physically located in the MRI magnet room.
Once patient is connected to MRI compatible monitors, everyone involved needs to be sure they have no metal on their bodies/clothes/jewelry/pens/ ID cards/phones etc. prior to entry into the MRI magnet room.
Once ready, DC the propofol infusion, transport patient into the MRI magnet room, connect to the anesthesia machine ventilator and initiate an inhalational GA technique. Position patient in the magnet, checking for length of IV tubing, breathing circuit and pressure points padded.
Administer additional muscle relaxant prior to leaving the MRI room.
In the control room is a computer monitor that has Centricity on the desktop that can be used for manually entering vital signs and drug administration.
The patient will be scanned for accurate fiber optic wire placement. Once accuracy is confirmed, the Visualase monitor will be just outside the control room door where the actual thermal ablation can be observed.
Once procedure is completed, patient is wheeled out of the MRI room back to the MRI holding area where propofol infusion is re started and transport monitors are replaced. Surgeon will remove the frame, wires and suture the scalp incisions prior to transport back to PACU for emergence.
Once in PACU propofol is discontinued, muscle relaxant is reversed and patient is extubated.
Anti-emetics are important to minimize post op nausea and vomiting resulting in potential cerebral edema and /or hemorrhage.
Complications from this procedure include Transient neurological deficits (dysphasia, hemianopia, and weakness), permanent neurological symptoms, intracranial hemorrhage, ventriculitis, intracranial hypertension, deep venous thrombosis.
Alternatively, on occasion due to lack of OR time, this entire procedure has been done in the MRI holding area with wire placement in the MRI tube itself. The protocol would be unchanged essentially but patient would have to be ventilated with an AMBU bag on a propofol infusion until ready to be moved to the MRI magnet room since there is no anesthesia machine in the MRI holding area. It’s unreasonable to drag the MRI compatible machine out of the magnet room to ventilate the patient then drag it back when patient is moved to the MRI tube. We are currently working on a fix to have a spare machine stored in the MRI holding area to facilitate inducing down in MRI.