G Iaconetta1, E Tessitore, M Samii. 1. Department of Neurosurgery, Federico University, Naples Italy. iaconetta@libero.it
Abstract
OBJECT: The anatomy of the abducent nerve is well known; its duplication (ranging from 5 to 28.6%), however, has rarely been reported in the literature. The authors performed a microanatomical study in 100 cadaveric specimens (50 heads) to evaluate the prevalence of this phenomenon and to provide a clear anatomical description of the course and relationships of the nerve. The surgery-related implications of this rare anatomical variant will be highlighted. METHODS: The 50 human cadaveric heads (100 specimens) were embalmed in a 10% formalin solution for 3 weeks. Fifteen of them were injected with colored neoprene latex. A duplicated abducent nerve was found in eight specimens (8%). In two (25%) of these eight specimens the nerve originated at the pontomedullary sulcus as two independent trunks: in one case the superior trunk was thicker than the inferior and in the other it was thinner. In the other six cases (75%) the nerve originated as a single trunk, splitting in two trunks into the cisternal segment: in two of them the trunks ran below the Gruber ligament, whereas in four specimens one trunk ran below and one above it. In all the specimens, the duplicated nerves fused again into the cavernous sinus, just after the posterior genu of the internal carotid artery. CONCLUSIONS: Although the presence of a duplicated abducent nerve is a rare finding, preoperative magnetic resonance imaging should be performed to rule out this possibility, thus tailoring the operation to avoid postoperative deficits.
OBJECT: The anatomy of the abducent nerve is well known; its duplication (ranging from 5 to 28.6%), however, has rarely been reported in the literature. The authors performed a microanatomical study in 100 cadaveric specimens (50 heads) to evaluate the prevalence of this phenomenon and to provide a clear anatomical description of the course and relationships of the nerve. The surgery-related implications of this rare anatomical variant will be highlighted. METHODS: The 50 human cadaveric heads (100 specimens) were embalmed in a 10% formalin solution for 3 weeks. Fifteen of them were injected with colored neoprene latex. A duplicated abducent nerve was found in eight specimens (8%). In two (25%) of these eight specimens the nerve originated at the pontomedullary sulcus as two independent trunks: in one case the superior trunk was thicker than the inferior and in the other it was thinner. In the other six cases (75%) the nerve originated as a single trunk, splitting in two trunks into the cisternal segment: in two of them the trunks ran below the Gruber ligament, whereas in four specimens one trunk ran below and one above it. In all the specimens, the duplicated nerves fused again into the cavernous sinus, just after the posterior genu of the internal carotid artery. CONCLUSIONS: Although the presence of a duplicated abducent nerve is a rare finding, preoperative magnetic resonance imaging should be performed to rule out this possibility, thus tailoring the operation to avoid postoperative deficits.
Authors: Joseph L Demer; Robert A Clark; Roberta M da Silva Costa; Jennifer Kung; Lawrence Yoo Journal: Ann N Y Acad Sci Date: 2011-09 Impact factor: 5.691
Authors: Giorgio Iaconetta; Matteo de Notaris; Arnau Benet; Jordina Rincon; Luigi Maria Cavallo; Alberto Prats-Galino; Madjid Samii; Paolo Cappabianca Journal: Neurosurg Rev Date: 2012-10-13 Impact factor: 3.042
Authors: Michelle Peng; Vadims Poukens; Roberta Martins da Silva Costa; Lawrence Yoo; Lawrence Tychsen; Joseph L Demer Journal: Invest Ophthalmol Vis Sci Date: 2010-04-30 Impact factor: 4.799