Complication avoidance in laser interstitial thermal therapy: lessons learned

Abstract

OBJECTIVE Complications of laser interstitial thermal therapy (LITT) are underreported. The authors discuss how they have modified their technique in the context of technical and treatment-related adverse events. METHODS The Medtronic Visualase system was used in 49 procedures in 46 patients. Between 1 and 3 cooling catheters/laser fiber assemblies were placed, for a total of 62 implanted devices. Devices were placed using frameless stereotaxy (n = 3), frameless stereotaxy with intraoperative MRI (iMRI) (n = 9), iMRI under direct vision (n = 2), MRI alone (n = 1), or frame-based (n = 47) techniques. LITT was performed while monitoring MRI thermometry. Indications included brain tumors (n = 12), radiation necrosis (n = 2), filum terminale ependymoma (n = 1), mesial temporal lobe epilepsy (n = 21), corpus callosotomy for bifrontal epilepsy (n = 3), cavernoma (n = 1), and hypothalamic hamartomas (n = 6). RESULTS Some form of adverse event occurred in 11 (22.4%) of 49 procedures. These included 4 catheter malpositions, 3 intracranial hemorrhages, 3 cases of neurological deficit related to thermal injury, and 1 technical malfunction resulting in an aborted procedure. Of these, direct thermal injury was the only cause of prolonged neurological morbidity and occurred in 3 of 49 procedures. Use of frameless stereotaxy and increased numbers of devices were associated with significantly increased complication rates (p < 0.05). A number of procedural modifications were made to avoid complications, including the use of 1) frame-based catheter placement, a 1.8-mm alignment rod to create a track and titanium skull anchors for long trajectories to improve accuracy; 2) a narrow-gauge instrument for dural puncture and coregistration of contrast MRI with CT angiography to reduce intracranial hemorrhage; 3) general endotracheal anesthesia for posterior-placed skull anchors to reduce the likelihood of damage to the cooling catheter; 4) use of as few probes as possible to reduce complications overall; and 5) dose modification of thermal treatment and use of short (3-mm) diffusing tips to limit treatment when structures to be spared do not have intervening CSF spaces to act as heat sinks. CONCLUSIONS Laser ablation treatment may be used for a variety of neurosurgical procedures for patients with tumors and epilepsy. While catheter placement and thermal treatment may be associated with a range of suboptimal operative and postoperative courses, permanent neurological morbidity is less common. The authors' institutional experience illustrates a number of measures that may be taken to improve outcomes using this important new tool in the neurosurgical arsenal.

Magnetic Resonance Imaging-Guided Laser Interstitial Thermal Therapy for Treatment of Drug-Resistant Epilepsy

“…A recent review by Pruitt et al [31] highlighted 3 potential points when complications may arise: during catheter placement, LiTT hyperthermia, and technical malfunctioning of the cooling system. Suboptimal catheter placement is associated with hemorrhage (subdural, arterial, subarachnoid) at a rate of 1.2% (3 of 243 patients reviewed).…”

“…Suboptimal catheter placement is associated with hemorrhage (subdural, arterial, subarachnoid) at a rate of 1.2% (3 of 243 patients reviewed). Pruitt et al [31] propose that the risks of hemorrhage may be reduced by using a sharp instrument for dural puncture and fusing computed tomography angiography/MRI and verifying vascular landmark. Commercial systems have safety protocols that shut off the system to prevent tissue vaporization and carbonization so overheating is not a significant concern.…”

The Future of Cranial Neurosurgery—Adapting New Approaches

“…51 While these complications are of course concerning, the authors of the paper offer several viable means of avoiding such complications in the future, including the use of CTA fusion to MRI to avoid critical vascular structures and needle puncture of the dura to prevent epidural hematoma formation. 51 Likewise, unintended thermal damage to surrounding tissue can be mitigated by carefully selecting targets which are in close proximity to cerebrospinal fluid (CSF) spaces which can serve as "heat sinks." 51 Finally, complications arising from inaccurate catheter placement can be minimized with a strong working knowledge of the neuronavigation system being used and its limitations.…”

“…The most commonly described complications include hemorrhage, incorrectly positioned catheters, and unintended thermal injury to eloquent brain tissue. 51 A recent paper reviewing the literature noted 4 cases of hemorrhage with 2 secondary to device positioning, 1 secondary to device removal, and 1 resulting from incomplete dural puncture. 51 While these complications are of course concerning, the authors of the paper offer several viable means of avoiding such complications in the future, including the use of CTA fusion to MRI to avoid critical vascular structures and needle puncture of the dura to prevent epidural hematoma formation.…”

“…51 A recent paper reviewing the literature noted 4 cases of hemorrhage with 2 secondary to device positioning, 1 secondary to device removal, and 1 resulting from incomplete dural puncture. 51 While these complications are of course concerning, the authors of the paper offer several viable means of avoiding such complications in the future, including the use of CTA fusion to MRI to avoid critical vascular structures and needle puncture of the dura to prevent epidural hematoma formation. 51 Likewise, unintended thermal damage to surrounding tissue can be mitigated by carefully selecting targets which are in close proximity to cerebrospinal fluid (CSF) spaces which can serve as "heat sinks."…”