Lesion of the Subthalamic Nucleus Should Not be Labeled “Subthalamotomy”; A Plea for Anatomical Accuracy and Compliance with Historical Legacy

Functional stereotactic neurosurgery requires the utmost precision, not only in anatomical targeting, but also in correct and precise labeling of the anatomical structure that is being targeted. The excellent recent publication by Paschen et al. is entitled “Comparative study of focused ultrasound unilateral thalamotomy and subthalamotomy for medication‐refractory Parkinson's disease tremor”. ¹ By “subthalamotomy” the authors describe lesions in the subthalamic nucleus (STN). However, naming lesions in the STN “subthalamotomy” is a misnomer. It should be “subthalamic nucleotomy” instead. Subthalamotomy has a long and rich history starting in the 1950s, when it concerned producing stereotactic therapeutic lesions in the posterior subthalamic area, ² in between the nucleus ruber and the STN (Fig. 1), while avoiding specifically any lesioning of the STN proper for fear of producing hemiballism. Areas of interest in that historical subthalamotomy era encompassed the fields of Forel, that is, pallido‐thalamic projections, the prelemniscal radiations, the zona incerta, and the cerebello‐thalamic pathways, but never the STN. ³ This Journal's guidelines for “Letters to the Editor”, allow a limited number of references, which is why we list here only the names and publication dates of some historical authors who used radiofrequency subthalamotomy for tremor or other movement disorders: Wertheimer 1960; Spiegel 1962; Andy 1963; Mundinger 1965 and 1968; Gillingham 1966 and 1968; Meier 1966; Houdart 1966; Blacker 1968; Fager 1968; Hullay 1970; Nittner 1970; Diederich 1992; Kim 1972; Schiffter 1972; Struppler 1974; Gros 1976; Ohye 1976; Krauss 1992; and Babel 2001. Even in the old era of deep brain stimulation (DBS), authors such as Feinstein 1968, Mundinger 1977, Brice 1980, and Andy 1983 targeted the subthalamic area excluding the STN. Full references of the publications of the aforementioned authors can be found in Blomstedt et al. ²

FIG. 1.

Coronal view of the thalamus and posterior subthalamus on the right hemisphere. The area in green depicts locations for thalamotomies and subthalamotomies (green contour). The red nucleus (Ru) is outlined in red. The subthalamic nucleus (Sth) is indicated in yellow. The blue line corresponds to the level of the intercommissural line and delineates the thalamus from the subthalamus. [Color figure can be viewed at wileyonlinelibrary.com]

Even in the contemporary era of DBS, when some authors compared the effect on tremor between stimulating the ventral intermediate nucleus (VIM) thalamus or the subthalamic area (not the STN), the title of the publication in question was: “Most effective stimulation site in subthalamic deep brain stimulation for Parkinson's disease”. ⁴

Furthermore, when experimental lesioning of the STN in the MPTP monkey was published by one of the pioneers in this field, the title read: “Subthalamic nucleotomy alleviates parkinsonism in the 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP)‐exposed primate”. ⁵ And when the STN started to be lesioned in humans using either radiofrequency ⁶ or Gamma Knife, ⁷ authors were careful to call it “subthalamic nucleotomy”, precisely to differentiate it from the classical subthalamotomy.

Finally, since the introduction of DBS in the STN in 1993, virtually all the literature about this subject specifies that it is DBS of the subthalamic nucleus not merely subthalamic stimulation. The accepted and widely used abbreviation is STN‐DBS not ST‐DBS. So, when making lesions in the STN by focused ultrasound or other means, why not label it as subthalamic nucleotomy, not merely a subthalamotomy. This would be more precise and anatomically accurate, would avoid confusion with the classical subthalamotomy, and would also show faithfulness to the work of our ancestors and to the whole field of stereotactic ablative neurosurgery for movement disorders.

Author Roles

(1) Research Project: A. Conception, B. Organization, C. Execution; (2) Statistical Analysis: A. Design, B. Execution, C. Review and Critique; (3) Manuscript Preparation: A. Writing of the First Draft, B. Review and Critique.

M.H.: 1A, 1B, 1C, 3A, 3B.

J.R.: 3B.

L.Z.: 3B.

M.T.K.: 3B.

H.A.: 3B.

P.B.: 1B, 1C, 3B.

All authors take responsibility for the integrity of the data analysis.

Data Availability Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.