Shamim Ara

White fiber dissection of brain; the internal capsule: a cadaveric study.

AIM This study was done to study the three dimensional anatomy of internal capsules white fibers completely by cadaveric dissection and its relation to basal ganglia and other related anatomical structures. MATERIAL AND METHODS Eight formalin fixed cerebral hemispheres were dissected for internal capsule under operating microscope. Klinglers technique of fiber dissection was adopted. The internal capsule was dissected from superiolateral inferior and medial surface of cerebral hemisphere. During and after dissection its relation with basal ganglia and other related structures were studied. RESULTS The internal capsule was demonstrated by dissecting fibers of all its parts. Fibers that forms the internal capsule originate from different parts of cerebral cortex and pass through corona radiata that lies in lateral periventricular area and lateral to the caudate nucleus above the upper border of lentiform nucleus. The internal capsule is situated medial to lentiform nucleus and lateral to caudate nucleus and thalamus. Caudally it continues in the midbrain as cerebral peduncle. It has an anterior limb, genu, posterior limb, retrolentiform and sublentiform part. The relation of different parts of internal capsule with surrounding structures were also shown. CONCLUSION Knowledge of the microsurgical anatomy of the internal capsule and other white fibers tracts is essential for neurosurgeons and other neuroscientists.

Transcranial microsurgical and endoscopic endonasal cavernous sinus (CS) anatomy: a cadaveric study.

AIMS AND OBJECTIVES Even in the era of tremendous microneurosurgical and endoscopic development, the cavernous sinus (CS) is a challenging anatomical site for a neurosurgeon. Many transcranial and a few endoscopic cadaveric studies have been done to study the CS; probably none were undertaken to study its microsurgical and endoscopic anatomy side by side. In this cadaveric study we perform a side-by-side comparison of the microsurgical and endoscopic anatomy of the CS that can help neurosurgeons deal with CS lesions more efficiently. MATERIALS AND METHOD Sixteen fresh cadaveric heads were studied after dissection. Six heads were dissected for transcranial study and six for endoscopic study of CS. During the transcranial study, the supratentorial brain was removed in three heads and CS and related anatomical structures were dissected. In the remaining heads, the CS was studied by keeping the brains in situ. In four heads both transcranial and endoscopic study was done simultaneously. Following dissection, microsurgical and endoscopic anatomy of CS was studied. RESULT The CS and related anatomical structures were dissected sequentially in all cases (transcranially in 10 [6 + 4] heads; endoscopically in 10 [6 + 4] heads), and their relationship was studied. CONCLUSION Microscopic and endoscopic exposure of the CS is relatively easy in cadavers. But endoscopic or microsurgical exposure of the CS during surgery is more difficult requiring skill. With experience of the cadaveric study , the CS may be explored via transcranial microsurgery, endonasal endoscopy, or both simultaneously, according to the nature and extension of the pathology.

Endoscopic endonasal transsphenoidal exposure of circle of Willis (CW); can it be applied in vascular neurosurgery in the near future? A cadaveric study of 26 cases.

AIM Endonasal transsphenoidal approaches are getting rapidly popular in removing many midline skullbase lesions from crista galli to foramen magnum. For safe removal of these lesions, familiarity with endoscopic endonasal anatomy of circle of Willis is very important. Furthermore, for safe development of this approach in vascular neurosurgery in the near future, endoscopic endonasal exposure of circle of Willis is a fundamental step. The goals in this study were to dissect the circle of Willis completely through the endoscopic endonasal approach and to become more familiar with the views and skills associated with the technique by using fresh cadaveric specimens. MATERIAL AND METHODS After obtaining ethical clearance, 26 fresh cadaver heads were used without any preparation. Using a neuroendoscope, complete exposure of the circle of Willis was done endonasaly, and various observations including relation of circle of Willis was recorded. RESULTS Complete exposure of the circle of Willis was made through an endonasal approach in all cases without injuring surrounding structures. CONCLUSION Endoscopic endonasal extended transsphenoidal exposure of CW can make the surgeon more efficient in removing midline skullbase lesions with safe handling of different parts of circle of Willis and it may help in development of endonasal endoscopic vascular neurosurgery in the near future.

White Fiber Dissection of Brain: Safety of Different Commonly Used Transcortical Microsurgical Approaches to Ventricles in Relation to Damage of the Internal Capsule and Other White Fiber Tract

Objectives: This study was conducted to analyze the safety of transcortical (frontal, parietal, and temporal transcortical approaches to the ventricles) approaches with respect to damage caused to the internal capsule and other white fiber tracts by conducting sequential white fiber dissection of the brain in cadaver. Methods: Eight formalin-fixed cerebral hemispheres were dissected for visualizing white fibers under operating microscope by the Klinger technique and their association with the basal ganglia and other related structures were studied. A standard middle temporal gyrus incision was made with a sharp knife and was deepened perpendicular to the surface to reach the temporal horn. By using the Klinger technique 11 formalin-fixed cerebral hemispheres were dissected for visualizing optic radiation under the microscope and was examined for any damage caused to optic radiation. A standard middle frontal gyrus incision was made and was deepened inferio-medially with an angle of 20 degrees to the sagittal plane to reach the lateral ventricle. Another incision on the superior parietal lobule was made and was deepened inferio-medially with an angle of 25 degrees to the perpendicular plane to reach the atrium of lateral ventricle. Another set of 6 formalin-fixed cerebral hemispheres was dissected and examined for any damage caused to the internal capsule and other white fiber tracts. Results: Internal capsule was dissected completely and its association with the surrounding structures were shown. No damage of any part of the internal capsule including optic radiation was found with the middle frontal, superior parietal lobule, and middle temporal gyrus transcortical approaches to the ventricles. Conclusions: Commonly used transcortical approaches to the ventricles are relatively safe with respect to causing damage to the internal capsule.