THE EFFECTIVENESS OF INTRAOPERATIVE ULTRASOUND IN GLIAL TUMOR SURGERY

Glial tumors constitute a significant proportion of central nervous system neoplasms. The main treatment modalities include surgery, radiotherapy, and/or chemotherapy. Patient prognosis depends on tumor grade, the extent of surgical resection, and, when indicated, the effectiveness of adjuvant treatment. The use of intraoperative ultrasound (IOUS) may provide real-time information during surgery and may facilitate maximal safe resection.

The aim of this retrospective study was to evaluate the role of IOUS in glial tumor surgery, with particular attention to residual tumor detection, postoperative edema, and neurological outcome in patients operated on with and without IOUS guidance.

The study included 35 patients with histologically confirmed glial tumors who underwent surgical treatment between 2020 and 2026. Twenty patients underwent surgery with IOUS guidance, whereas 15 underwent microsurgical resection without IOUS. IOUS was performed using SONOLINE G50 (Siemens) and ACUSON X300 (Siemens) systems with 5-10 MHz transducers. Preoperative and postoperative neurological status was assessed clinically by neurosurgeons and neurologists. Postoperative CT was performed on the second postoperative day; contrast-enhanced MRI was performed later, within 21 days to 1 month after surgery. Because standardized KPS or mRS scores and early MRI within 48 hours were not available in this retrospective series, radiological and neurological outcomes were analyzed as descriptive clinical categories.

High-grade tumors (WHO grade III-IV) were diagnosed in 25 patients and low-grade tumors (WHO grade I-II) in 10 patients. In the IOUS group, 16 patients had high-grade and 4 had low-grade tumors; in the non-IOUS group, 9 patients had high-grade and 6 had low-grade tumors. Residual tumor was detected in 7 of 20 patients in the IOUS group and in 9 of 15 patients in the non-IOUS group. Neurological status improved in 12 patients, remained unchanged in 7, and worsened in 1 in the IOUS group; in the non-IOUS group, neurological status improved in 1 patient, remained unchanged in 13, and worsened in 1. Overall postoperative edema increased in 2 cases, remained unchanged in 22, and decreased in 11.

IOUS is a useful adjunct in glial tumor surgery because it provides real-time intraoperative information regarding tumor localization, internal structure, and relationship to surrounding brain tissue. In this retrospective cohort, IOUS was associated with a lower frequency of residual tumor and a more favorable trend in neurological outcome, although the absence of volumetric early postoperative MRI and standardized neurological scores limits definitive conclusions.