Evaluation of the Cranial Aperture of the Optic Canal on Cone-Beam Computed Tomography Images and its Clinical Implications for the Transcranial Approaches.

OBJECTIVE: This study aimed to investigate morphometric properties of the cranial aperture (CA) of the optic canal. METHODS: Cone-beam computed tomography images of 400 individuals (200 males and 200 females) aged 37.32 ± 15.87 years were retrospectively examined to assess the morphometry and morphology of the CA. RESULTS: The height and width of CA were found as 4.22 ± 0.74 mm and 7.27 ± 1.15 mm, respectively. The distances between the CA and the midsagittal line, the anterior and lateral boundaries of the anterior skull base were measured as 5.77 ± 1.32 mm, 64.97 ± 6.36 mm, and 41.00 ± 4.05, respectively. The angle of the optic canal in the sagittal plane was measured as 7.57° ± 3.95°, whereas in the horizontal plane as 38.96° ± 4.36°. The aperture shape was defined as the tear-drop (413 foramina, 51.62%), triangular (180 foramina, 22.50%), oval (158 foramina, 19.75%), round (30 foramina, 3.75%), and polygonal (19 foramina, 2.38%). CONCLUSIONS: The authors observed that the diameters, and angulations of the CA may change relative to gender and the shape. The anatomic features of CA are important for the positioning of the patient's head, the choice of the appropriate surgical approach or equipment, and the detection of anatomical landmarks during interventions. In this context, our dataset may be beneficial for surgeons helpful as a reference for radiological evaluations.

Anatomical Evaluation of the Foramen Magnum on Cone-Beam Computed Tomography Images and Review of Literature.

Background and objective The morphology and morphometry of the foramen magnum (FM), which provides a passageway to vital neurological structures that relay information to and from the brain and spinal cord, are significant for many surgical approaches and applications. It was aimed to investigate the morphometric and morphological features of the FM on the cone-beam computed tomography (CBCT) images and to review the literature in detail. Methods CBCT images of 400 individuals (200 males, 200 females, aged between 18 and 65) were evaluated by Planmeca Romexis Viewer. The length, width, perimeter, and area of the FM were examined and samples were classified according to shape. Also, the FM index (FMI) was calculated. Results The mean values of the length, width, and perimeter were found to be 36.75±2.50 mm, 32.55±2.93 mm, and 108.35±7.50 mm, respectively. The area of FM was found to be 941.81±128.26 mm2, 946.83±127.39 mm2, and 895.76±123.50 mm2 with Planmeca Romexis Viewer, Radinsky formula, and Teixeira formula, respectively. All parameters were significantly larger in males than females. There was no correlation between age and these parameters. Also, seven shapes were determined for FM, and the most common shape was oval. FM index was evaluated according to the Martin and Saller classification. It was found that 16.5% of the cases belonged to the narrow, 16% belonged to the medium, and 67.5% to the large FM index. There was no correlation between age and FM index. Conclusion Morphometric and morphological features of the FM located in the craniovertebral junction (CVJ), which is a highly complex area, are variable. Surgical procedures and approaches in this region are essential due to the high mortality rate. For this reason, anatomical structures in these regions should be well known before surgery. The quantitative data presented in this study, which made a detailed literature comparison, may assist in surgical procedures around the FM and the planning of these procedures.

A Thick Anastomotic Vein Between Cephalic and Lateral Radial Veins: Clinical Significance of an Unusual Variation.

This study presents a thick anastomosis between the cephalic vein and lateral radial vein which, to the best of our knowledge, has not been reported before in the literature. During routine cadaver dissection in the right upper extremity of a 54-year-old male cadaver; in the anterior cubital region, a very thick anastomotic branch was found by piercing the deep fascia, going upwards and laterally, and joining the cephalic vein. Deep dissection results showed that this branch provided an anastomosis between the lateral radial vein and cephalic vein. Despite that variations of superficial veins in the upper extremity are common, the presence of a branch connecting deep and superficial veins is a rare situation. It is well known that veins in the cubital fossa are essential in traditional diagnosis and treatment procedures. Arteriovenous fistula procedure is a widely used method applied by creating a fistula between the cephalic vein or basilic vein and the brachial artery to provide vascular access for hemodialysis in patients with chronic renal failure. Drainage of the lateral radial vein into the cephalic vein through a thick branch, as determined in this case, may disrupt venous drainage in the forearm in an arteriovenous fistula procedure performed between the cephalic vein and the brachial artery. On the other hand, in such a case, if the basilic vein is preferred for this procedure, it is thought that the rate of impairment of venous drainage may be less.

Radiologic evaluation of the fossa navicularis: incidence, morphometric features, and clinical implications.

INTRODUCTION: The aim of this study was to determine the incidence and morphometric and morphological characteristics of fossa navicularis (FN) on cone beam computed tomography (CBCT) images of healthy adults MATERIALS AND METHODS: CBCT images of 900 individuals (450 males, 450 females, over the age of 18) admitted to Gaziantep University, Dentistry Faculty were retrospectively examined. The incidence and shape of FN were determined. Transverse diameter (TDFN), sagittal diameter (SDFN), depth in transverse section (DFNT), depth in sagittal section (DFNS), and the shortest distance between the deepest point of FN and intracranial cavity (FNI) were measured. RESULTS: FN was detected in 122 (59 males and 63 females) of 900 (13.56%) CBCT images. No statistically significant difference was observed between gender and the incidence of FN. SDFN, TDFN, DFNS, DFNT and FNI were measured as 4.04 ± 1.71, 4.28 ± 1.34, 1.79 ± 0.68, 2.34 ± 0.85, and 6.76 ± 2.23 mm, respectively. Besides, FN was described as oval in 95 of 122 (77.87%) cases, while as round in 27 (22.23%) cases. CONCLUSIONS: The incidence of FN is rare; however, it may be responsible for serious consequences by causing infections from the nasopharynx to the intracranial cavity. As far as we know, the distance between the deepest point of FN and the intracranial cavity was measured for the first time in the literature with this study.

Anatomic features of the fetal round and oval windows, and their relations with the tympanic nerve.

OBJECTIVE: The study aimed to examine morphometric properties of the round window (RW) and oval window (OW) and to show their relation with the tympanic nerve (the Jacobson's nerve, JN) in human fetuses from the otologic surgeon's perspective. METHODS: Thirty temporal bones of 15 fetal cadavers (8 males, 7 females) aged with 24.40 ± 3.71 weeks were included in the study. The height, width and surface area of the RW and OW and also distance from the JN to the OW and RW were measured. RESULTS: The height, width and surface area of the RW in this work were measured as 1.48 ± 0.25 mm, 1.57 ± 0.37 mm, and 2.05 ± 0.69 mm2, respectively. The RW was detected as round-shaped (8 cases, 26.7%), oval-shaped (15 cases, 50%), and dome-shaped (7 cases, 23.3%). The height, width and surface area of the OW were measured as 1.42 ± 0.26 mm, 2.90 ± 0.44 mm, and 3.63 ± 0.74 mm2, respectively. The OW was observed as oval-shaped (15 cases, 50%), kidney-shaped (10 cases, 33.3%), D-shaped (4 cases, 13.3%), and trapezoid-shaped (1 case, 3.3%). The JN was found 1.21 ± 0.60 and 1.18 ± 0.54 mm away from the RW and OW, respectively. CONCLUSION: This study containing morphological data about the shapes, diameters and area of the RW and OW may be useful to predict surgical difficulty, and to select implants of suitable size preoperatively for the windows. Knowing the relationship between the JN and the windows can be helpful to avoid iatrogenic injuries of the nerve.

Anatomic features of the cranial aperture of the optic canal in children: a radiologic study.

OBJECTIVE: This study aimed to peruse anatomic features of the cranial aperture of the optic canal (CAOC) for obtaining an extended morphometric dataset in children. METHODS: Computed tomography images of 200 children were included in this retrospective work to analyze the shape, location and diameters of the CAOC. RESULTS: The CAOC area, width and height were observed as 17.53 ± 2.80 mm2, 6.12 ± 0.84 mm, and 4.35 ± 0.64 mm, respectively. The angle of the optic canal in axial plane was found as 39.28 ± 5.13°, while in sagittal plane as 16.01 ± 6.76°. The distance between the CAOC and the midsagittal line was 7.17 ± 1.48 mm. The CAOC was measured as 54.04 ± 5.23 mm and 42.55 ± 3.28 mm away from the anterior and lateral boundary of the anterior skull base, respectively. The CAOC shape was described as the tear-drop (186 foramina, 46.5%), triangular (156 foramina, 39%), oval (47 foramina, 11.8%), and round (11 foramina, 2.8%). CONCLUSION: The depth, angle and diameter measurements belonging to the CAOC were changing according to its shape or demographic data (e.g., sex and age). Therefore, preoperative radiologic evaluation containing the shape, location and size of the CAOC should be considered by multidisciplinary operating teams in terms of surgical interventions such as implant positioning.