The Dorello Canal

Historical Development, Controversies in Microsurgical Anatomy, and Clinical Implications

Varun R. Kshettry, M.D; Joung H. Lee, M.D; Mario Ammirati M.D., M.B.A


Neurosurg Focus. 2013;34(3):e4 

In This Article

Abstract and Introduction


Interest in studying the anatomy of the abducent nerve arose from early clinical experience with abducent palsy seen in middle ear infection. Primo Dorello, an Italian anatomist working in Rome in the early 1900s, studied the anatomy of the petroclival region to formulate his own explanation of this pathological entity. His work led to his being credited with the discovery of the canal that bears his name, although this structure had been described 50 years previously by Wenzel Leopold Gruber. Renewed interest in the anatomy of this region arose due to advances in surgical approaches to tumors of the petroclival region and the need to explain the abducent palsies seen in trauma, intracranial hypotension, and aneurysms. The advent of the surgical microscope has allowed more detailed anatomical studies, and numerous articles have been published in the last 2 decades. The current article highlights the historical development of the study of the Dorello canal. A review of the anatomical studies of this structure is provided, followed by a brief overview of clinical considerations.


In the early 1900s, there was considerable debate regarding the origin of abducent palsy seen with acute or chronic middle ear infections. In 1904, Giuseppe Gradenigo (1859–1926), an Italian otolaryngologist, described a syndrome characterized by a triad of middle ear infection, ipsilateral abducent paralysis, and ipsilateral trigeminal neuropathic pain most commonly manifested as retroorbital pain due to irritation of the ophthalmic division of the trigeminal nerve.[14–16] The mechanism of abducent palsy was vehemently debated among his contemporaries. Gradenigo himself believed that inflammation of the tympanic cavity spread to the leptomeninges,[14,17] although he was uncertain of the mechanism whereby this occurred. In 1905, an Italian anatomist, Primo Dorello (1872–1963), offered his own theory on the possible cause of abducent nerve palsy in Gradenigo syndrome based on anatomical dissections done to study the course of the abducent nerve.[13]