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Updated: Jun 17, 2026

Minimally Invasive Thumb-sized Pterional Craniotomy for Surgical Clip Ligation of Unruptured Anterior Circulation Aneurysms
Published on: August 11, 2015
"In-window" craniotomy and "bridgelike" duraplasty: an alternative to decompressive hemicraniectomy
Marcelo M Valença1, Carolina Martins, Joacil Carlos da Silva
1Neurosurgery Unit, Federal University of Pernambuco, Pernambuco, Brazil. mmvalenca@yahoo.com.br
Object:
The object of this study was to propose an alternative procedure to the classic decompressive hemicraniectomy using an "in-window" craniotomy and a "bridgelike" duraplasty.
Methods:
The authors performed a large, almost rectangular craniotomy involving the frontal, temporal, and parietal bones and part of the occipital squama in 5 patients. The dura mater is opened and its area is enlarged using a rectangular dural patch of the surgeon's choice in the form of a bridge between the anterior and posterior dural edges. With a vertical cut, the bone flap is divided into 2 similarly sized pieces that function as "window lids." The outer frontal and occipital sides of the bone are tied to the skull border at 2 points to function as a hinge joint. The angle of the bone cut must be beveled outward (inclination ~ 45° of the bone drill or saw) to allow the bone flap to rest on the adjacent skull and prevent its slippage toward the intracranial cavity.
Results:
The above procedures were performed with effective control of intracranial hypertension due to cerebral venous sinus thrombosis, brain trauma, intracerebral hematoma, or malignant cerebral ischemia.
Conclusions:
Decompressive surgery, which uses an in-window craniotomy that gradually opens according to the intracranial pressure, is an alternative solution for deploying autologous material. The procedure has the advantage of obviating the need for a second surgical procedure to close the bone defect, and thus preventing the metabolic cerebral impairment associated with the absence of an overlying skull.

