Scalp marking for a craniotomy using a laser pointer during preoperative computed tomographic imaging: Technical note

OBJECTIVE: The preoperative localization of superficial intracranial lesion s is often necessary for accurate burr hole placement or craniotomy siting. It is not always easy, however, to localize the lesions over the scalp wor king only from computed tomographic images. We developed a simple method fo r such localization using a laser pointer during the preoperative computed tomographic examination. METHODS: The angle of incidence, extending from a point on the scalp to the center of the computed tomographic image, is measured by the software incl uded with the scanner. In the gantry, at the same angle as on the image, a laser is beamed from a handmade projector onto the patient's scalp toward t he center of the gantry. The point illuminated on the patient's head corres ponds to that on the image. The device and the method are described in deta il herein. RESULTS: We applied this technique to mark the area for the craniotomy befo re surgery in five patients with superficial brain tumors. At the time of s urgery, it was confirmed that the tumors were circumscribed precisely. CONCLUSION: The technique is easy to perform and useful in the preoperative planning for a craniotomy. In addition, the device is easily constructed a nd inexpensive.