{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,1]],"date-time":"2026-04-01T07:10:34Z","timestamp":1775027434525,"version":"3.50.1"},"reference-count":34,"publisher":"Journal of Neurosurgery Publishing Group (JNSPG)","issue":"3","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2024,3,1]]},"abstract":"<jats:sec>\n<jats:title>OBJECTIVE<\/jats:title>\n<jats:p>Anatomical triangles provide neurosurgeons with the specificity required to access deep targets, supplementing more general instructions, such as craniotomy and approach. The infragalenic triangle (IGT), bordered by the basal vein of Rosenthal (BVR), precentral cerebellar vein (PCV), and the quadrangular lobule of the cerebellum, is one of a system of anatomical triangles recently introduced to guide dissection to brainstem cavernous malformations and has not been described in detail. This study aimed to quantitatively analyze the anatomical parameters of the IGT and present key nuances for its microsurgical use.<\/jats:p>\n<\/jats:sec>\n<jats:sec>\n<jats:title>METHODS<\/jats:title>\n<jats:p>A midline supracerebellar infratentorial (SCIT) approach through a torcular craniotomy was performed on 5 cadaveric heads, and the IGT was identified in each specimen bilaterally. Anatomical measurements were obtained with point coordinates collected using neuronavigation. Three cadaveric brains were used to illustrate relevant brainstem anatomy, and 3D virtual modeling was used to simulate various perspectives of the IGT through different approach angles. In addition, 2 illustrative surgical cases are presented.<\/jats:p>\n<\/jats:sec>\n<jats:sec>\n<jats:title>RESULTS<\/jats:title>\n<jats:p>The longest edge of the IGT was the lateral edge formed by the BVR (mean \u00b1 SD length 19.1 \u00b1 2.3 mm), and the shortest edge was the medial edge formed by the PCV (13.9 \u00b1 3.6 mm). The mean surface area of the IGT was 110 \u00b1 34.2 mm<jats:sup>2<\/jats:sup> in the standard exposure. Full expansion of all 3 edges (arachnoid dissection, mobilization, and retraction) resulted in a mean area of 226.0 \u00b1 48.8 mm<jats:sup>2<\/jats:sup> and a 2.5-times increase in surface area exposure of deep structures (e.g., brainstem and thalamus). Thus, almost the entire tectal plate and its relevant safe entry zones can be exposed through an expanded unilateral IGT except for the contralateral inferior colliculus, access to which is usually hindered by PCV tributaries. Exposure of bilateral IGTs may be required to resect larger midline lesions to increase surgical maneuverability or to access the contralateral pulvinar.<\/jats:p>\n<\/jats:sec>\n<jats:sec>\n<jats:title>CONCLUSIONS<\/jats:title>\n<jats:p>The IGT provides a safe access route to the dorsal midbrain and reliable intraoperative guidance in the deep and complex anatomy of the posterior tentorial incisura. Its potential for expansion makes it a versatile anatomical corridor not only for intrinsic brainstem lesions but also for tumors and vascular malformations of the pineal region, dorsal midbrain, and posteromedial thalamus.<\/jats:p>\n<\/jats:sec>","DOI":"10.3171\/2023.6.jns222871","type":"journal-article","created":{"date-parts":[[2023,9,30]],"date-time":"2023-09-30T03:44:56Z","timestamp":1696045496000},"page":"866-879","source":"Crossref","is-referenced-by-count":7,"title":["Infragalenic triangle as a gateway to dorsal midbrain and posteromedial thalamic lesions: descriptive and quantitative analysis of microsurgical anatomy"],"prefix":"10.3171","volume":"140","author":[{"given":"Sahin","family":"Hanalioglu","sequence":"first","affiliation":[{"name":"Department of Neurosurgery, Barrow Neurological Institute, St. Joseph\u2019s Hospital and Medical Center, Phoenix, Arizona"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Muhammet Enes","family":"Gurses","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Barrow Neurological Institute, St. Joseph\u2019s Hospital and Medical Center, Phoenix, Arizona"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Giancarlo","family":"Mignucci-Jim\u00e9nez","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Barrow Neurological Institute, St. Joseph\u2019s Hospital and Medical Center, Phoenix, Arizona"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Nicolas I.","family":"Gonz\u00e1lez-Romo","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Barrow Neurological Institute, St. Joseph\u2019s Hospital and Medical Center, Phoenix, Arizona"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ethan A.","family":"Winkler","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Barrow Neurological Institute, St. Joseph\u2019s Hospital and Medical Center, Phoenix, Arizona"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mark C.","family":"Preul","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Barrow Neurological Institute, St. Joseph\u2019s Hospital and Medical Center, Phoenix, Arizona"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Michael T.","family":"Lawton","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Barrow Neurological Institute, St. Joseph\u2019s Hospital and Medical Center, Phoenix, Arizona"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1754","reference":[{"key":"b1","series-title":"World Neurosurg","first-page":"79","article-title":"Anatomical triangles for use in skull base surgery: a comprehensive review","volume":"164","author":"Hendricks BK","year":"2022","unstructured":"Hendricks BK, Benet A, Lawrence PM, Benner D, Preul MC, Lawton MT. 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