The keyhole concept in aneurysm surgery: results of the past 20 years.

BACKGROUND: Improvements in preoperative imaging and intraoperative visualization have led to a refinement in surgical techniques. OBJECTIVE: Report of a 20-year experience with application of the keyhole technique as a contribution to the ongoing debate on the impact of limited craniotomies in aneurysm surgery. METHODS: Over a 20-year period, 1000 consecutive patients with 1297 aneurysms were surgically treated in 1062 operations: 651 in the acute stage after SAH and 411 with unruptured aneurysms. The outcome was assessed with the modified Rankin scale and approach-related complications. RESULTS: The majority of the cases were treated by 4 different keyhole approaches: The supraorbital approach was used in 793 patients for 989 aneurysms, the subtemporal in 48 patients for 50 aneurysms, the interhemispheric in 46 patients for 51 aneurysms, and the retromastoidal in 55 patients for 55 aneurysms. In 120 patients, the classic pterional approach was applied to treat 152 aneurysms. The results of unruptured aneurysms were good (modified Rankin scale ≤ 2) in 96.52%. The complication rates of the keyhole approaches were less than in the pterional group, although the difference did not reach statistical significance. CONCLUSION: The overall outcome, rate of retreatment, and approach-related complications with keyhole approaches for the management of ruptured and unruptured aneurysms are comparable to recently published conventional surgical aneurysm series. In addition to the common benefits of limited-exposure approaches, this series demonstrates appropriate safety and applicability of the keyhole technique in aneurysm surgery.

[Biportal neuroendoscopy of the prepontine cisterns]. / A praepontin ciszternák biportalis neuroendoszkópiája.

INTRODUCTION: While bi- or multiportal approaches have been adopted in different fields of surgery including abdominal and spine surgery, the uniportal access into the skull is a traditional principle in neurosurgery. In this preclinical cadaver study the authors developed combinations of biportal endoneurosurgical dissections in the prepontine subarachnoid space to test the safety of this technique. METHODS: In 34 fresh post-mortem adult human cadavers and 14 formaldehyde-fixed adult human head specimen a total of 48 biportal endoscopical dissections were carried out. 0 degree, 30 degrees, and 70 degrees lens scopes with a diameter of 1.7 and 4.2 mm and trochars with a diameter of 5.0 to 6.5 mm were used. RESULTS: Six different endoscopic routes to the prepontine region and a total of 10 different combinations of this approaches could be described. Useful and safe biportal combinations were: 1. supraorbital on both sides, 2. supraorbital combined with ipsilateral anterior subtemporal, 3. supraorbital combined with contralateral anterior subtemporal, 4. supraorbital combined with ipsilateral posterior subtemporal, 5. supraorbital combined with ipsilateral frontal interhemispheric, 6. supraorbital combined with contralateral frontal interhemispheric, 7. anterior subtemporal combined with ipsilateral frontal interhemispheric, 8. anterior subtemporal combined with contralateral frontal interhemispheric. CONCLUSION: The biportal endomicrosurgical strategy offered effective and safe dissections within the prepontine subarachnoid space.

Topographic microsurgical anatomy of the paraclinoid carotid artery.

In this publication, the authors describe the microanatomic topography of the entire paraclinoid area with respect to the paraclinoid segment of the internal carotid artery and its surrounding anatomical structures. Special attention was given to the borders of the paraclinoid area, cavernous sinus, arterial vessels, and cranial nerves passing through the region. The paraclinoid region was defined as a pyramid-formed space formed by the dural covering of the anterior clinoid process. The superior border is formed by the continuity of the anterior petroclinoid fold, anteriorly on the superior surface of the anterior clinoid process and medially in the direction of the diaphragma sellae. This dural sheet encircles the internal carotid artery and forms the so-called distal dural ring of the internal carotid artery. The medial border of the paraclinoid region is formed by the body of the sphenoid bone and the adjacent periosteal sheet. The inferior border is formed by a fibrous plate between the middle and anterior clinoid processes. This so-called proximal dural ring separates the venous compartments of the cavernous area from the paraclinoid area. The lateral border is formed by the lateral surface of the anterior clinoid process with its dural covering. The arterial supply of this region is provided by branches of the intracavernous carotid segment and the ophthalmic artery. The important nerves in close vicinity to the paraclinoidal area are the optic and the oculomotor nerves. Understanding and knowledge of the topographic anatomy of the paraclinoid area is essential for microsurgical exposure of this region.