Comprehensive morphometric analysis of the rhomboid fossa: implications for safe entry zones in brainstem surgery.

BACKGROUND: The rhomboid fossa (RF) is a crucial anatomical region in brainstem surgery, as it contains essential structures like the reticular formation and cranial nerve nuclei. This study aims to provide a detailed understanding of the RF's complex microsurgical anatomy, which is vital for the safe execution of neurosurgical procedures. METHODS: Morphometric analysis was conducted on 45 adult human brainstems preserved in 10% formalin. Thirteen linear measurements were performed under 20x magnification, using a millimeter graph to identify key anatomical landmarks. RESULTS: The study provided precise measurements of the rhomboid fossa, with a length of 34.65 mm and a width of 22.61 mm. The facial colliculus (FC) measured 4.26 mm in length on the left and 4.45 mm on the right, with corresponding widths of 3.77 mm and 3.50 mm. The distance between the sulcus limitans incisures was 9.52 mm, while the distance from the upper border of the medullary striae to obex was 11.53 mm. The proximity of the FC to the median sulcus was measured at 0.86 mm on the right and 0.96 mm on the left. Additionally, two safe entry zones-the suprafacial and infrafacial triangles-were identified, offering pathways to reach dorsal pons lesions through the RF. CONCLUSION: This comprehensive morphometric analysis of the RF enhances the understanding of its intricate anatomy. By describing safe entry zones, the suprafacial and infrafacial triangles, and providing precise measurements of key anatomical features, this research serves as a valuable resource for neurosurgeons in planning and executing brainstem surgeries.

Microsurgical anatomy of safe entry zones on the ventrolateral brainstem: a morphometric study.

Surgery of the brainstem is challenging due to the complexity of the area with cranial nerve nuclei, reticular formation, and ascending and descending fibers. Safe entry zones are required to reach the intrinsic lesions of the brainstem. The aim of this study was to provide detailed measurements for anatomical landmark zones of the ventrolateral surface of the human brainstem related to previously described safe entry zones. In this study, 53 complete and 34 midsagittal brainstems were measured using a stainless caliper with an accuracy of 0.01 mm. The distance between the pontomesencephalic and bulbopontine sulci was measured as 26.94 mm. Basilar sulcus-lateral side of pons (origin of the fibers of the trigeminal nerve) distance was 17.23 mm, transverse length of the pyramid 5.42 mm, and vertical length of the pyramid 21.36 mm. Lateral mesencephalic sulcus was 12.73 mm, distance of the lateral mesencephalic sulcus to the oculomotor nerve 13.85 mm, and distance of trigeminal nerve to the upper tip of pyramid 17.58 mm. The transverse length for the inferior olive at midpoint and vertical length were measured as 5.21 mm and 14.77 mm, consequently. The thickness of the superior colliculus was 4.36 mm, and the inferior colliculus 5.06 mm; length of the tectum was 14.5 mm and interpeduncular fossa 11.26 mm. Profound anatomical knowledge and careful analysis of preoperative imaging are mandatory before surgery of the brainstem lesions. The results presented in this study will serve neurosurgeons operating in the brainstem region.

The effect of hyperbaric oxygen on neuroregeneration following acute thoracic spinal cord injury.

AIMS: Although hyperbaric oxygen (HBO) treatment following spinal cord injury (SCI) have been studied in terms of neurological function and tissue histology, there is a limited number studies on spinal cord tissue enzyme levels. MAIN METHODS: The effect of HBO treatment in SCI was investigated by measuring superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), nitric oxide synthase (NOS) and nitric oxide (NO) activity in the injured tissue. SCI was induced by applying an aneurysm clip extradurally at the level of T9-T11 vertebrae. Preoperative HBO (preopHBO) treatment was applied for 5days and postoperative HBO (postopHBO) for 7days. KEY FINDINGS: In the preopHBO group, a significant decrease was observed in NOS and NO compared to the SCI group. There was a decrease in SOD, NOS and NO in the postopHBO group when compared to the SCI group. In the pre-postHBO group SOD, GPx, NOS and NO decreased significantly. There was a decrease in SOD in postopHBO compared to preopHBO. In the prepostopHBO, SOD decreased significantly compared to that in the preopHBO group. The prepostopHBO presented a significant decrease in GPx compared to postopHBO (p<0.05 for all parameters). No significant difference was observed for catalase for all groups. Significant improvement was found in BBB scores for both postopHBO and prepostHBO groups when compared to the SCI group (p<0.05). SIGNIFICANCE: HBO treatment was found to be beneficial following SCI in terms of biochemical parameters and functional recovery in the postoperative period.

Morphometry of the cervical vertebral pedicles as a guide for transpedicular screw fixation.

Anatomical measurements of the cervical pedicle in a large series of human cervical vertebrae from 48 individuals were obtained to reduce the incidence and severity of complications caused by transpedicular screw placement. The greatest pedicle length was at C-3 and the greatest pedicle width was at C-6. Pedicle width and lateral mass thickness gradually increased from C-3 to C-6. Pedicle height and interpedicular distance increased from C-3 to C-5, and decreased slightly at C-6. The lateral mass-pedicle length was greatest at C-4. The present study found right-left differences for the pedicle-spinous process distance at C-6 (p < 0.05). Pedicle width and height were smaller than those reported in earlier studies, especially at C-3 and C-4, whereas the increasing pedicle widths at C-5 and C-6 were appropriate for pedicle screw fixation.

Incidence and morphology of the accessory head of the flexor pollicis longus muscle (Gantzer`s muscle) in a Turkish population.

OBJECTIVE: To present the incidence, morphology, and the relationships of the accessory head of the flexor pollicis longus (Gantzer`s) muscle (AHFPL) in a recent Turkish population. METHODS: The study was performed on 52 upper extremities of 26 adult Turkish cadavers in the Department of Anatomy, Ege University Faculty of Medicine, Izmir, Turkey in 2005. In our dissections, the prevalence and anatomical morphology of the AHFPL including muscle shape, origin and insertion point, and its relation to the anterior interosseous nerve (AIN) was examined. RESULTS: The AHFPL muscle was found in 27 upper extremities (51.9%). It was bilateral in 10 cadavers (74%), and unilateral in 7 cadavers (26%). The muscle shape was spindle in 19 (70.4%), and papillary in 8 (29.6%). The AHFPL originated from the coronoid process of the ulna in 22 upper extremities (81.5%), and the medial epicondyle of the humerus in 5 cases (18.5%). The AIN passed anterior to the AHFPL in one case (3.7%), lateral in 3 (11.1%), posterolateral in 8 (29.6%) and posterior in 15 (55.6%) cases. CONCLUSION: The knowledge of the morphology and the topography of the AIN and AHFPL is important for understanding the mechanism of the AIN syndrome. The results of this study show the mechanical compression due to the AHFPL may be a cause of the pronator and AIN syndromes.

Topographic anatomy of the fornix as a guide for the transcallosal-interforniceal approach with a special emphasis on sex differences.

The topographic anatomy and morphometry of the fornix is important for standardizing the transcallosal-interforniceal approach and avoiding memory disturbances. The detailed morphometry of the fornix was investigated with a special emphasis on sex differences using midsagittal magnetic resonance imaging of 80 males and 102 females. Various parameters of the fornix, including the length of the upper and lower fornices, the curvature of the upper and lower fornices, and the insertion point of the fornix to corpus callosum, were investigated. The thickness of the fornix at the attachment point to the anterior commissure, the maximum distance to the upper and lower surfaces of the fornix, and the curvature of the upper and lower fornices showed sex differences (p < 0.5). The upper insertion point of the fornix to the corpus callosum was more frontal in females, but the functional relevance of these differences need further investigation.

Variations in sphenoid sinus anatomy with special emphasis on pneumatization and endoscopic anatomic distances.

OBJECTIVE: The purpose of this study was to present the morphometry and pneumatization of the sphenoid sinus in detail for the neurosurgeon for transnasal approach to the hypophyseal tumors and especially for functional endoscopic sinus surgery. METHODS: One hundred and eighty midsagittal magnetic resonance images, 48 bones and 29 hemi-sectioned cadaveric heads obtained from Ege University, Faculty of Medicine, Departments of Anatomy and Radiology were used in 2003. The sphenoid sinuses were classified into sellar, pre-sellar, conchal and post-sellar types according to the extent of their posterior limits. Different measurements based on the surgical approach and sinus size were performed. RESULTS: Conchal type sinus was observed in 1.9%, pre-sellar type 9%, sellar type 52.9% and post-sellar type 36.2% of the specimens. Conchal type sphenoid sinus was not observed in males, but in 1.7% of females. Pre-sellar type was observed in 5.6% of males and 2.8% of females. Sellar type was found in 24.4% of males and 23.9% females, and post-sellar type in 19.5% of males and 22.2% of females. The sphenoid sinus length at the upper and lower parts was 13.51+/-3.25mm and 24.57+/-6.65mm. The sphenoid sinus height at the anterior and posterior parts was 21.27+/-4.25mm and 14.5+/-4.07mm. Distance from the ostium to limen was 56.6+/-5.6mm and from ostium to sill was 64.6+/-6.11mm in cadaveric specimens. In MR images, distance from the ostium to the sill was 68.7+/-5.9mm and from sella to sill 82.8+/-6.2mm. CONCLUSION: Sphenoid sinus variations observed in pneumatization, size, localization and shape are important in providing a better surgical approach and avoiding surgical complications.

Morphometry of the anterior third ventricle region as a guide for the transcallosal-interforniceal approach.

The transcallosal-interforniceal approach is the most appropriate approach to localize and totally remove space-occupying lesions around the anterior third ventricle region such as craniopharyngiomas and gliomas. This study examined the microsurgical anatomy of the normal anterior third ventricle region in 81 adult cadaver hemispheres. The central sulcus was identified and surface landmarks determined as the points 5 cm (P5) and 7 cm anterior to the central sulcus (P7). The distances between P5 and P7 and the upper margin of the interventricular foramen, which delineate the surgical corridor chosen to avoid disturbance of important neural structures, were 46.26-60.96 (54.09 +/- 3.35) mm and 48.00-62.00 (54.94 +/- 3.09) mm, respectively. The distances between the upper margin of the hemisphere and the cingulate sulcus, especially important for avoiding damage to the cingulate gyrus and other mesiolimbic structures, were 13.54-30.00 (21.28 +/- 3.89) mm and 12.22-29.52 (21.12 +/- 3.90) mm at the level of P5 and P7. The distances between the upper margin of the hemisphere and the callosal cistern containing the pericallosal artery were 28.34-40.50 (33.94 +/- 2.84) mm and 28.16-40.26 (33.50 +/- 2.61) mm, respectively. Normative morphometric data of the structures involved in the surgical procedure are necessary for planning and performance of the transcallosal-interforniceal approaches. This study of a large series of specimens shows that these measurements have large individual variations.

Anatomy of the clinoidal region with special emphasis on the caroticoclinoid foramen and interclinoid osseous bridge in a recent Turkish population.

In this study we present the incidence of caroticoclinoid foramen and interclinoid osseous bridge and some topographic aspects regarding the clinoidal internal carotid artery (ICA) in a recent Turkish population to provide a guide for neurosurgeons in any surgical approach, especially to the cavernous sinus. One hundred nineteen adult dry skulls and 52 adult cadaveric heads were used for this purpose. Caroticoclinoid foramen and the interclinoid osseous bridge were divided into three types based on the classification of Keyers [13]. Caroticoclinoid foramen was observed in 35.67% of the specimens, unilaterally in 23.98%, and bilaterally in 11.69%. The complete-type caroticoclinoid foramen was observed in 4.09% of the specimens, the contact type in 4.68%, and the incomplete type in 14.91%. Transverse diameter of the foramen was 5.32+/-0.52 mm for the incomplete type. The incidence of interclinoid osseous bridge was 8.18%. The middle clinoid process was prominent in 15.12% of cases and rudimental in 13.23%. The mean distance between the proximal and distal dural rings of the clinoidal ICA was 4.51+/-0.44 mm, and mean diameter of the distal ring was 5.25+/-0.59 mm. Right-left differences were assessed for each parameter, and populational differences are discussed.

Heights of the cerebral falx. Surgical and clinical implications.

OBJECTIVE: Variations in the shape and size of the cerebral falx can embarrass the surgical treatment of lesions in and around the falx. In this study, anatomy and morphometry of the cerebral falx in adult cadaveric specimens were examined to enable easy approach during surgery. METHODS: Fifty-two adult cadaver cerebral hemispheres with dura from the cadaver collection of the Department of Anatomy, Ege University, Faculty of Medicine were examined in 2003. The cerebral falx was observed in 3 different types. The heights of the cerebral falx and the heights of interspace between the lower margin of the cerebral falx and corpus callosum were measured. RESULTS: The most frequently observed type of cerebral falx was Type I based on the classification of Jiang and Jia. The average heights of the cerebral falx measured 21.3 mm anteriorly, 25.7 mm in the middle and 45.6 mm posteriorly in Type I; 27.9 mm anteriorly, 30.5 mm in the middle and 47 mm posteriorly in Type II; 28.7 mm anteriorly, 36.5 mm in the middle and 44.1 mm posteriorly in Type III. The average heights of the interspace between the lower margin of the cerebral falx and corpus callosum were 14.1 mm anteriorly, 12.4 mm in the middle and 2.1 mm posteriorly in Type I; 6.3 mm anteriorly, 7.2 mm in the middle and 1 mm posteriorly in Type II; 2.3 mm anteriorly, 1.8 mm in the middle and 0.6 mm posteriorly in Type III. Natural defects were found on the cerebral falx in 12 (23%) specimens. CONCLUSION: Measurements of the cerebral falx provide useful information for neurosurgeons in treatment of lesions involving the region. This study presents more detailed data compared to those reported in the few previously published papers, results differing due to differences of the populations investigated.

Morphometry of the anterior third ventricle region as a guide for the subfrontal (translaminaterminalis) approach.

The anterior third ventricle region acquires clinical significance in benign and malignant tumors and cyst formations, of which craniopharyngiomas and gliomas are the most common. The subfrontal approach is one of the most preferred approaches for removing these tumors. In this study, the microsurgical anatomy of 81 Turkish, adult cadaveric hemispheres was examined to provide morphometric data of the region. These measurements from the anterior third ventricle region serve as a guide for neurosurgeons during surgical approach for removing anterior third ventricle tumors.