TY - JOUR
T1 - Comprehensive anatomy of the foramen ovale critical to percutaneous stereotactic radiofrequency rhizotomy
T2 - Cadaveric study of dry skulls
AU - Elnashar, Adel
AU - Patel, Smruti K.
AU - Kurbanov, Almaz
AU - Zvereva, Kseniya
AU - Keller, Jeffrey T.
AU - Grande, Andrew W.
N1 - Publisher Copyright:
© AANS 2020, except where prohibited by US copyright law.
PY - 2020/5
Y1 - 2020/5
N2 - OBJECTIVE Percutaneous stereotactic radiofrequency rhizotomy (PSR) is often used to treat trigeminal neuralgia, a serious condition that results in lancinating, episodic facial pain. Thorough understanding of the microsurgical anatomy of the foramen ovale (FO) and its surrounding structures is required for efficient, effective, and safe use of this technique. This morphometric study compares anatomical and surgical orientations to identify the variations of the FO and assess cannulation difficulty. METHODS Bilateral foramina from 174 adult human dry skulls (348 foramina) were analyzed using anatomical and surgical orientations in photographs from standardized projections. Measurements were obtained for shape, size, adjacent structures, and morphometric variability effect on cannulation. The risk of potential injury to surrounding structures was also assessed. RESULTS The authors identified 6 distinctive shapes of the FO and 5 anomalous variants from the anatomical view, and 6 shapes from the surgical view. In measurements of surface area of this foramen obtained using the surgical view, loss (average 18.5% ± 5.7%) was significant compared with the anatomical view. Morphometrically, foramen size varied significantly and obstruction from a calcified pterygoalar ligament occurred in 7.8% of specimens. Importantly, 8% of foramina were difficult to cannulate, thus posing a 12% risk of inadvertent cannulation of the foramen lacerum. CONCLUSIONS Significant variability in the FO’s shape and size probably affected its safe and effective cannulation. Preoperative imaging by 3D head CT may be helpful in predicting ease of cannulation and in guiding treatment decisions, such as a percutaneous approach over microvascular decompression or radiosurgery.
AB - OBJECTIVE Percutaneous stereotactic radiofrequency rhizotomy (PSR) is often used to treat trigeminal neuralgia, a serious condition that results in lancinating, episodic facial pain. Thorough understanding of the microsurgical anatomy of the foramen ovale (FO) and its surrounding structures is required for efficient, effective, and safe use of this technique. This morphometric study compares anatomical and surgical orientations to identify the variations of the FO and assess cannulation difficulty. METHODS Bilateral foramina from 174 adult human dry skulls (348 foramina) were analyzed using anatomical and surgical orientations in photographs from standardized projections. Measurements were obtained for shape, size, adjacent structures, and morphometric variability effect on cannulation. The risk of potential injury to surrounding structures was also assessed. RESULTS The authors identified 6 distinctive shapes of the FO and 5 anomalous variants from the anatomical view, and 6 shapes from the surgical view. In measurements of surface area of this foramen obtained using the surgical view, loss (average 18.5% ± 5.7%) was significant compared with the anatomical view. Morphometrically, foramen size varied significantly and obstruction from a calcified pterygoalar ligament occurred in 7.8% of specimens. Importantly, 8% of foramina were difficult to cannulate, thus posing a 12% risk of inadvertent cannulation of the foramen lacerum. CONCLUSIONS Significant variability in the FO’s shape and size probably affected its safe and effective cannulation. Preoperative imaging by 3D head CT may be helpful in predicting ease of cannulation and in guiding treatment decisions, such as a percutaneous approach over microvascular decompression or radiosurgery.
KW - Foramen ovale
KW - Neuroanatomy
KW - Pain
KW - Percutaneous stereotactic radiofrequency rhizotomy
KW - Pterygoalar bar
KW - Pterygospinous ligament
KW - Trigeminal nerve
KW - Trigeminal neuralgia
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U2 - 10.3171/2019.1.JNS18899
DO - 10.3171/2019.1.JNS18899
M3 - Article
C2 - 31003215
AN - SCOPUS:85084235546
SN - 0022-3085
VL - 132
SP - 1414
EP - 1422
JO - Journal of neurosurgery
JF - Journal of neurosurgery
IS - 5
ER -