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.

OBJECTIVE: To compare anatomically the surgical exposure provided by pterional (PT), orbitozygomatic (OZ), and minisupraorbital (SO) craniotomies. @@METHODS:@@ Seven sides of six fixed cadaver heads injected with silicone were used. The mini-SO craniotomy followed by the PT and OZ approaches were performed sequentially. The bony flaps were attached with miniplates and screws, allowing easy conversion between the approaches. A frameless stereotactic device was used to calculate an area of surgical exposure and the angles of approach for six different anatomic targets. An image guidance system was used to demonstrate the limits of the surgical exposure for each technique. RESULTS: No significant differences were observed in the total area of surgical exposure when comparing the mini-SO (A = 1831.2 ± 415.3 mm2), PT (A = 1860.0 ± 617.2 mm2), and OZ approaches (A = 1843.3 ± 358.1 mm2; P > 0.05). Angular exposure was greater for the OZ and PT approaches than for the mini-SO approach, either in the vertical and horizontal axes, considering all of the six targets studied (P< 0.05). Except for the distal segment of the ipsilateral sylvian fissure, no practical differences in the limits of the exposure were detected. CONCLUSION: The mini-SO approach may offer a similar surgical working area compared with that provided by standard craniotomies and constitutes an excellent alternative to the OZ and PT craniotomies in selected patients. Selection should not be based primarily on the area to be exposed, but rather on the working angles that are anticipated to be required. The key point is to use the most adequate technique for a particular patient, rather than using a one-size-fits-all approach for all patients.

Cerebral hemodynamics and metabolism are frequently impaired in a wide range of neurological diseases, including traumatic brain injury and stroke, with several pathophysiological mechanisms of injury. The resultant uncoupling of cerebral blood flow and metabolism can trigger secondary brain lesions, particularly in early phases, consequently worsening the patient's outcome. Cerebral blood flow regulation is influenced by blood gas content, blood viscosity, body temperature, cardiac output, altitude, cerebrovascular autoregulation, and neurovascular coupling, mediated by chemical agents such as nitric oxide (NO), carbon monoxide (CO), eicosanoid products, oxygen-derived free radicals, endothelins, K+, H+, and adenosine. A better understanding of these factors is valuable for the management of neurocritical care patients. The assessment of both cerebral hemodynamics and metabolism in the acute phase of neurocritical care conditions may contribute to a more effective planning of therapeutic strategies for reducing secondary brain lesions. In this review, the authors have discussed concepts of cerebral hemodynamics, considering aspects of clinical importance.

The vertical and horizontal angles of approach to the AComA complex are significantly larger for the OPT and OZ approaches compared with the PT approach. Use of the OZ approach may decrease the need for frontal lobe retraction and resection of the gyrus rectus.

Wrapping or clip-wrapping of unclippable intracranial aneurysms is safe and seems to confer protection against aneurysmal growth or subarachnoid hemorrhage.

Exposure of the basal cisterns and circle of Willis by the PT approach is optimized when dissection of the SF reaches the anterior ascendant ramus. Further splitting of the SF provides no additional gain.

-Cerebral hemiatrophy or Dyke-Davidoff-Masson syndrome is a condition characterized by seizures, facial asymmetry, contralateral hemiplegia or hemiparesis, and mental retardation. These findings are due to cerebral injury that may occur early in life or in utero. The radiological features are unilateral loss of cerebral volume and associated compensatory bone alterations in the calvarium, like thickening, hyperpneumatization of the paranasal sinuses and mastoid cells and elevation of the petrous ridge. The authors describe three cases. Classical findings of the syndrome are present in variable degrees according to the extent of the brain injury. Pathogenesis is commented.KEY WORDS: Dyke-Davidoff-Masson syndrome, brain atrophy, computerized tomography, magnetic resonance image.Achados radiológicos na síndrome de Dyke-Davidoff-Masson: relato de três casos e contribuição para patogênese e diagnóstico diferencial RESUMO -Hemiatrofia cerebral ou síndrome de Dyke-Davidoff-Masson é entidade clínica caracterizada por convulsões, assimetria facial , hemiparesia ou hemiplegia contralateral e déficit cognitivo. Estes achados estão relacionados a lesão cerebral ocorrida na infância ou in utero. As características radiológicas são hemiatrofia cerebral e alteracões ósseas no crânio, como espessamento, hiperpneumatização dos seios paranasais e células da mastóide e elevação do ápice da pirâmide petrosa. Descrevemos três casos com achados clássicos da síndrome discutindo aspectos fisiopatológicos. PALAVRAS-CHAVE: síndrome de Dyke-Davidoff-Masson, atrofia cerebral, tomografia computadorizada, ressonância magnética.

Except for the vertical angle to the rostral aspect of the fourth ventricle, the telovelar approach provides greater angle of exposure in all planes than the transvermian approach. Removal of the C1 posterior arch obviates this sole advantage of the transvermian approach. The telovelar approach offers a corridor through noneloquent arachnoid planes and a safe and capacious working environment.