Browsing by Author "Govsa, F"

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    Anatomical determination of a safe entry point for occipital condyle screw using three-dimensional landmarks
    Ozer, MA; Celik, S; Govsa, F; Ulusoy, MO
    The occipital condyle (OC) is an important area in craniovertebral surgery, but neither its anatomical features nor the procedures concerning the OC have been detailed yet. The morphological analysis of the structures were made in totally 704 sides of the occipital bones of adult skulls by 3D-Doctor Demo version. The length and width of the OC were found to be 23.9 +/- A 3.4 (right), 24 +/- A 3.3 (left) and 11.9 +/- A 2.3 (right), 10.7 +/- A 2.3 mm (left), respectively. The mean anterior intercondylar distance and the posterior intercondylar distance were measured as 20.9 +/- A 3.6 and 43.1 +/- A 4 mm, respectively. The sagittal intercondylar angle was observed as 68.7 +/- A 10.6A(0). The sagittal condylar angle was observed to be 32.9 +/- A 7.6A(0) and 38.2 +/- A 7.3A(0) in the right and left, respectively. The head circumference was observed to be 65.6 +/- A 7.8 and 64.4 +/- A 7.2 mm in the right and left, respectively. The head area was measured as 231.9 +/- A 53.3 and 214.9 +/- A 45.1 mmA(2) in the right and left, respectively. The most common type was oval-like (59.67%), whereas the most unusual one was two-portioned condyle (0.32%). In Pearson correlation analysis, it was significant that a statistically strong relation was noticed between the length and area, and the circumference and area. The findings suggest that the oval type was more successful to work with, while the triangular, circular and two-portioned types were highly risky for the fixation resonance as the surface got quite smaller. As a result, we suggest that by resecting nearly half of the OC, the border of the hypoglossal canal can be involved.
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    The cranio-orbital foramen, the groove on the lateral wall of the human orbit, and the orbital branch of the middle meningeal artery
    Erturk, M; Kayalioglu, G; Govsa, F; Varol, T; Ozgur, T
    The cranio-orbital foramen, a foramen in the lateral wall of the orbit, contains an anastomosis between the anterior branch of the middle meningeal artery and the lacrimal artery. Previous workers have speculated that the groove starting either from the cranio-orbital foramen or the lateral extremity of the superior orbital fissure contains the anastomotic artery. We investigated the cranio-orbital foramen and the groove on the lateral wall of the orbit in a series of 170 dried adult human skulls, and the course of the orbital branch of the middle meningeal artery in 74 specimens from 37 cadavers. We observed the cranio-orbital foramen in 141 skulls (82.9%). It was unilateral in 55 (32.4%) and bilateral in 86 (50.6%) skulls. The groove on the lateral wall of the human orbit was observed in 122 skulls (71.8%). It was unilateral in 40 (23.5%) and bilateral in 82 (48.2%). The groove on the lateral wall of the orbit started from the cranio-orbital foramen in 20 skulls (11.8%). The orbital branch of the middle meningeal artery was found in 48 cadaveric specimens (64.9%): 32 (43.2%) passed through the cranio-orbital foramen and 12 (16.2%) passed through the superior orbital fissure. In four specimens (5.4%), orbital branches of the middle meningeal artery passed through both the superior orbital fissure and the cranio-orbital foramen. The anatomy of the cranio-orbital foramen and the course of the orbital branch should be well known by surgeons reconstructing the anterior base of the skull, the orbit after orbital base surgery, and during excision of meningiomas. (C) 2004 Wiley-Liss, Inc.
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    Surgical implications of anatomical landmarks on the lateral surface of the mastoid bone
    Aslan, A; Mutlu, C; Celik, O; Govsa, F; Ozgur, T; Egrilmez, M
    The aim of this study was to examine the relationships of the surgical landmarks on the lateral surface of the mastoid bone with the landmarks in a deeper location. Simple mastoidectomy was carried out without drilling over the linea temporalis inferior (LTI) on 20 adult temporal bones. The suprameatal spine, i.e., Henle spine (HS), variants were noted. Morphometric measurements were performed between these surgical landmarks, and their variations with pneumatization or HS types were evaluated. Three types of HS were identified: triangular, crest, absent. The HS-lateral semicircular canal distance was 15 mm on average and longer in bones with a triangular HS than a crest type HS (16.4 vs. 14.3 mm). The LTI was found to be located on average 4.7 mm inferior to the middle fossa dural plate (MFD). The LTI-MFD distance had a tendency to be longer in bones without an HS than with a crest type of HS (5.9 vs. 3.9 mm). Chorda tympani emerged from the facial nerve at the stylomastoid foramen in five specimens (25%). This anatomical organization was not correlated with the type of HS. Korner's septum (KS) was identified in nine bones (45%). It was present in eight of 16 (50%) bones with good pneumatization. No tendency for the existence of KS was found for any specific type of HS. This study confirms that the mastoid antrum is located 15 mm deep to the lateral surface of the mastoid bone. It should be expected to be longer in bones with a triangular HS. In addition, the MFD is located on average 5 mm above the LTI, which could be useful information for beginners or inexperienced surgeons. The ear surgeon should anticipate that the MFD might be longer in bones without an HS.
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    The variational anatomy of the external aperture of the human vestibular aqueduct
    Mutlu, C; Govsa, F; Unlu, HH; Senyilmaz, Y
    A study was undertaken to demonstrate the variational anatomy of the external aperture of the vestibular aqueduct in 90 human temporal bones obtained from 58 cadavers, Topographic landmarks of the posterior surface of the petrous bone are useful for general orientation and include the external aperture of the vestibular aqueduct, internal auditory meatus, sigmoid sinus, subarcuate fossa, superior petrosal sinus and cochlear canaliculus. We determined the mean distances from the external aperture of vestibular aqueduct to the above structures to be 10.98, 11.21, 9.42, 10.27 and 13.90 mm, respectively. Furthermore, the length of the external aperture of the vestibular aqueduct revealed significant differences between the right and left sides. The distances between the EAVA and certain anatomical structures on the posterior surface of the temporal bone should be taken into consideration during surgery. Knowing the variability of the position of the external aperture of the vestibular aqueduct may help surgeons avoid traumatizing, and thus producing inadvertent lesions to the hearing mechanism.