gms | German Medical Science

Objective: To demonstrate a new concept of intraoperative use of high frequency Ultrasound (hfioUS) in maximizing the extent of resection (EOR) of intra-axial intracranial high-grade tumors.

Methods: 22 Patients harboring an intracranial high-grade tumor were retrospectively included in this study (14 primary tumors, 8 metastasis). 14 of them had a perilesional edema equal or greater to lesions volume, 3 had previously received radiotherapy. After macroscopical tumor debulking the small (11 x 31 mm) L15-7io (Philips, Bothell, USA) high-frequency probe (7–15 MHz) was introduced in the resection cavity and its walls were meticulously scanned searching for tumor remnants during resection. Postoperative MR scans were evaluated by a board-certified independent neuroradiologist to assessed the EOR.

Results: Gross total resection was achieved in 21 patients (95.5%). One patient had a small tumor remnant (6 x 4 x 3 mm) of a very large (80 x 60 x 74 mm) anaplastic astrocytoma, detected in the postoperative MR scan. A permanent postoperative hemiparesis was diagnosed in one patient with a metastasis in the motor area, all other patients recovered without permanent neurological deficits from the surgery.

Conclusions: In this study the hfioUS probe allowed a precise detection of the tumor and a detailed discrimination between normal, pathological and edematous tissue. The concept of high frequency close superficial intraoperative ultrasound scanning is superior to usual broad medium frequency scanning and thus a true alternative to high end intraoperative imaging.