Ablative brain surgery: an overview

Figures & data

Table 1. Advantages and disadvantages of the ablative techniques currently used in brain surgery.

	RF thermoablation	Radiosurgery	LITT	MRgFUS thermal ablation
Advantages	Distinct lesion borders Intraoperative physiological confirmation No limitation of the region of treatment Immediate results	External No limitation of the region of treatment Ablation of a large tissue volume Conformation of the lesion to complex geometries Radiobiologic effect is slower and may allow for more plasticity	Distinct lesion borders No limitation of the region of treatment Ablation of a large tissue volume Real-time monitoring of lesioning process with MRI and thermometry Immediate results	Distinct lesion borders Intraoperative physiological confirmation External Real-time monitoring of lesion process with MRI and thermometry Immediate results
Drawbacks	Surgical risk (intracerebral hemorrhage, loss of accuracy) Less predictability of lesion size and shape Requires multiple passes for the ablation of large volumes	Delayed effect Graduated dose fall-off and less demarcated lesion borders Exposure to ionizing radiation No intraoperative feedback	Surgical risk (intracerebral hemorrhage, loss of accuracy) Requires multiple passes for the ablation of large volumes MRI environment	Limited to central areas of the brain Head must be shaved Uncomfortable for claustrophobic patients Increased operative times MRI environment

Abbreviations: RF: radiofrequency; LITT: laser interstitial thermal therapy; MRgFUS: magnetic resonance-guided focused ultrasound; MRI: magnetic resonance imaging.

Figure 1. A neurosurgeon performing a stereotactic procedure at the hospital “Istituto Neurologico Carlo Besta” in Milan in the early 1980s.

Figure 2. A simulation of a stereotactic MRgFUS ablative procedure with the Kranion software. Temperature prediction is showed on the left side of the panel (maximal: red, average: green). MRgFUS: magnetic resonance-guided focused ultrasound.

Figure 3. Axial (left) and coronal (right) T2-weighted MRIs demonstrating unilateral thalamotomy (A), pallidotomy (B), and subthalamotomy (C) using transcranial MRgFUS. MRI: magnetic resonance imaging; MRgFUS: magnetic resonance-guided focused ultrasound.

Table 2. Lesion procedures.

Procedure	Indications	Method	Target	Side effects
Anterior capsulotomy	OCD	RF, SRS	Anterior limb of internal capsule	Weight gain, fatigue, memory loss, incontinence, seizure
Anterior cingulotomy	OCD, MDD, BD	RF	Anterior cingulate	Seizure
Subcaudate tractotomy	OCD, MDD, BD, anxiety	Yttrium-90 rods with RF, RS	Substantia innominata	Seizure
Limbic leucotomy	OCD, MDD, BD	Mechanical disruption, heat, radioactive materials, RF	Anterior cingulate, substantia innominata	Lethargy, perseveration, incontinence, somnolence, apathy, seizure

Abbreviations: OCD: obsessive-compulsive disorder; MDD: major depressive disorder; BD: bipolar disorder; RF: radiofrequency; SRS: stereotactic radiosurgery; Y-BOCS: Yale-Brown obsessive-compulsive scale.

Figure 4. Axial T1-weighted MRI sequence demonstrating bilateral anterior capsulotomy using stereotactic radiosurgery for obsessive-compulsive disorder. MRI: magnetic resonance imaging.

Table 3. Most common brain ablative procedures performed for chronic pain.

Site of lesion	Stereotactic coordinates for lesion placement, mm lateral/antero-posterior/vertical + ant and sup, - post and inf	Side effects	Intraoperative positive effects to stimulation
Posterior central-lateral nucleus	6/2 posterior to PC/ 0	Somatosensory deficits, pretectal deficits	Paresthesias, dysesthesias, pain relief
Cm/Pf	8–10/5 anterior to PC/+4	Somatonsensory deficits, oculomotor deficits/ verbal deficits	Tingling/painful burning sensation/unpleasant sensations (throbbing, pulling)
Lateral sensory thalamus
VPL	17/3 anterior to PC/+10	Somatosensory deficits, paresthesia, dysesthesia, central pain	Limbs paresthesia
VPM	10/2 anterior to PC/+17	Somatosensory deficits, paresthesia, dysesthesia, central pain	Face paresthesia
Anterior cingulate fasciculus	+5–7/20–25 posterior to the anterior tip of the frontal horn/1–2 above the roof of the lateral ventricle	Decreased attention, apathy, decreased spontaneity, impairment of executive functions, seizures	Short-term verbal memory deficit
Mesencephalon	5–10/5 posterior to PC/–5	Oculomotor disturbances, dysesthesias, ipo-anesthesia, ipo-analgesia, motor weakness	Tremor (medial lemniscus), burning pain, numbness, cold sensation (spinothalamic tract), vibration, pain, funny feeling, panic, hyperventilation, involuntary verbalization, pulse and respiration slowing, emotional reactions (reticular formation, periaqueductal gray)

Figure 5. Axial T2-weighted MRI demonstrating left-sided amygdalohippocampectomy and the associated catheter tract following LITT for MTLE. LITT: laser interstitial thermal therapy; MRI: magnetic resonance imaging; MTLE: mesial temporal lobe epilepsy.