Two neurosurgical centers, Bologna (Italy) and Freiburg (FRG), have compared results obtained with stereotactic mesencephalotomy (SM; Bologna) and multiple thalamotomies (MT; Freiburg) in the surgical treatment of chronic cancer pain syndromes. In total, 161 patients were operated, 109 in Bologna and 52 in Freiburg. In SM the lesions were single and centered on the spinothalamic tract at the mesencephalic level, while in MT the lesions were multiple in the thalamic nuclei (ventrocaudal parvocellular nucleus, nucleus limitans, lamella medialis, centromedian nuclei). The following results emerged after 2-7 months' follow-up: (1) in an antalgic sense, SM was much more beneficial, with 91 patients (83.5%) pain-free after the operation versus 27 patients (51.9%) who had only an attenuation of the pain syndrome after MT; (2) SM, compared to MT, is burdened by mortality and a higher morbidity [2 deaths (1.8%) vs. 0; 3 anesthesia dolorosa and 8 severe gaze palsies (10.1%) vs. only 1 case of permanent aphasia (1.9%)].