Minipterional Craniotomy Research Articles

130 Prospective Randomized Study Comparing Clinical, Functional and Aesthetics Results of Classical Pterional and Minipterional Craniotomies

130 Prospective Randomized Study Comparing Clinical, Functional and Aesthetics Results of Classical Pterional and Minipterional Craniotomies

Minipterional Craniotomy: An Alternative Approach for Sphenoid Wing Meningiomas

Objective: Minipterional craniotomy is a modification of the standard pterional (frontotemporal) craniotomy. It provides the same microsurgical exposure as the standard frontotemporal approach. Material and Methods: We analyzed the relation between the sphenozygomatic suture and the marginal tubercle of the frontal process of the zygoma 60 dried skulls. Minipterional craniotomy was performed in 10 cadaveric specimens. The approach was utilized to 12 sphenoid wing meningiomas. Results: The marginal tubercle was hiding the sphenozygomatic suture when it is > 8 mm, it required drilling to enhance the exposure. Anterior to posterior subperiosteal dissection and retraction of the temporalis muscle, and avoiding cuts along the origin of the muscle allows excellent cosmetic outcome. All 16 meningiomas were successfully resected without morbidity or mortality through a 3.5 to 4 cm bone flap. Conclusions: Minipterional approach is an excellent option to approach sphenoid wing meningiomas. The minimally invasive access allows minimal soft tissue trauma, smaller bony opening, less pain, and excellent cosmetic outcome.

The Minipterional Craniotomy for Anterior Circulation Aneurysms

The pterional craniotomy is well established for microsurgical clipping of most anterior circulation aneurysms. The incision and temporalis muscle dissection impacts postoperative recovery and cosmetic outcomes. The minipterional (MPT) craniotomy offers similar microsurgical corridors, with a substantially shorter incision, less muscle dissection, and a smaller craniotomy flap. To report our experience with the MPT craniotomy in select unruptured anterior circulation aneurysms. From January 2009 to July 2013, 82 unruptured aneurysms were treated in 72 patients, with 74 MPT craniotomies. Seven patients had multiple aneurysms treated with a single MPT craniotomy. The average patient age was 56 years (range: 24-87). Aneurysms were located along the middle cerebral artery (n = 36), posterior communicating (n = 22), paraophthalmic (n = 22), choroidal (n = 1), and dorsal ICA segments (n = 1). The MPT craniotomy utilized an incision just posterior to the hairline and a single myocutaneous flap. The average aneurysm size was 5.45 mm (range: 1-14). There were no instances of compromised operative corridors requiring craniotomy extension. Three significant early postoperative complications included epidural and subdural hematomas requiring evacuation, and a middle cerebral artery infarction. Average length of hospitalization was 3.96 days (range: 2-20). Two patients required reoperation for wound infections. Average follow-up was 421 days (range: 5-1618). Minimal to no temporalis muscle wasting was noted in 96% of patients. The MPT craniotomy is a worthwhile alternative to the standard pterional craniotomy. There were no instances of suboptimal operative corridors and clip applications when the MPT craniotomy was utilized in the treatment of unruptured middle cerebral artery and supraclinoid internal carotid artery aneurysms proximal to the terminal internal carotid artery bifurcation.

Perspective of the frontolateral craniotomies

The pterional craniotomy is one of the most frequently surgical approaches used in neurosurgery and currently it has become a mainsteam. It allows excellent microsurgical exposure of anterior and posterior regions of the arterial circle of Willis, supra and paraselar regions, the superior orbital fissure of sphenoid bone, cavernous sinus, orbit, temporal lobe, midbrain and the frontal lobe. Like others techniques, the pterional craniotomy presented disadvantages related to dissection of the temporal muscle. From the first fronto lateral craniotomy described by Dandy to expose the optic chiasm and the pituitary we pass through the Yasargil's classical description of craniotomy centered in fronto-temporal sylvian fissure until reaching the recent"minipterional craniotomy", modifications of the pterional craniotomy were proposed to reduce the extra cranial tissue trauma and reduce the area of craniotomy without affecting the exposure of surgical targets, thus improving their aesthetic and functional results. An historical analysis of the frontolateral approaches has demonstrated that they have evolved from larger craniotomies to smaller ones, however only the minipterional craniotomy is able to offer similar surgical exposure.

THE MINIPTERIONAL CRANIOTOMY

To describe a modification of the pterional approach (PT), the minipterional craniotomy (MPT), and compare the anatomic exposure provided by these two approaches. The anatomic exposure offered by the MPT and PT were compared in eight sides of cadaver heads using a computerized tracking system, a robotic microscope, and an image-guidance system. The area of surgical exposure, angular exposure, and anatomic limits of each craniotomy were evaluated. Three recently operated clinical cases (EGF) are also reported. There were no statistical differences in the total area of surgical exposure between the two craniotomies (PT, 1524.7 +/- 305 mm; MPT, 1469.7 +/- 380.3 mm; P > 0.05) or among the ipsilateral, middle, and contralateral components of the area (P > 0.05). There were no differences in angular exposure along the longitudinal and transverse axis angles for the three selected targets, the bifurcations of internal carotid and middle cerebral arteries, and the anterior communicating artery (P > 0.05). Except for the distal portion of the operculoinsular compartment of the sylvian fissure, no significant differences in the limits of the surgical exposure through the PT and MPT were apparent on the image-guidance system. The MPT craniotomy provides comparable surgical exposure to that offered by the PT. The advantages of the MPT include reduction of tissue trauma and bony removal, a decrease in surgical time, and improved cosmetic outcomes.