Shieff C, Nashold B S
Department of Neurosurgery, Royal Free Hospital, London, United Kingdom.
Neurosurg Clin N Am. 1990 Oct;1(4):825-39.
Within the mesencephalon lie nuclear masses and fiber tracts that connect higher and lower portions of the neuraxis. The pathways subserving epicritic (discriminatory) sensation and protopathic (motivational) sensation are adjacent to one another and can be localized precisely with stereotaxy. Discrete thermal lesions overflowing between the direct spinothalamic and quintothalamic pathways laterally and the more diffuse ascending pathways medially can be created. By careful target selection the surgeon can avoid significant damage to adjacent structures and offer relief of central or malignant pain without substantial sensory disturbance. At the same time the emotional disturbances that often persist with other remedies are reduced. Intraoperative electrophysiologic monitoring may help minimize unwanted and distressing side effects. It is fortunate that nature has designed the upper brain stem in such a fashion to allow effective pain relief procedures. Although stereotactic mesencephalotomy is not a panacea, it offers relief of pain syndromes that cannot otherwise be helped while abolishing the associated emotional problems that otherwise can be relieved only by psychosurgical procedures.
中脑内有核团和纤维束，它们连接着神经轴的上部和下部。分别传导精细（辨别性）感觉和原始（激发性）感觉的传导通路彼此相邻，并且可以通过立体定向技术精确地定位。可以在外侧的直接脊髓丘脑束和三叉丘脑束通路之间以及内侧更弥散的上行通路之间制造离散的热损伤。通过仔细选择靶点，外科医生可以避免对相邻结构造成重大损伤，并在不造成明显感觉障碍的情况下缓解中枢性或恶性疼痛。同时，常常伴随其他治疗方法而持续存在的情绪障碍也会减少。术中电生理监测可能有助于将不必要的和令人痛苦的副作用降至最低。幸运的是，大自然以这样一种方式设计了上脑干，使得有效的疼痛缓解程序成为可能。尽管立体定向中脑切开术不是万灵药，但它能缓解其他方法无法缓解的疼痛综合征，同时消除相关的情绪问题，而这些问题原本只能通过精神外科手术来缓解。
