gms | German Medical Science

Objective: Implementation of the intraoperative ultrasound (ioUS) during the neurosurgical procedure is of benefit for the patient and the neurosurgeon. We analyzed intraoperative ultrasonographic characteristics of miscellaneous intraspinal/intradural tumors and compared those to macroscopic findings intraoperatively.

Methods: For tumor localization and differentiation purposes, ultrasound images were obtained in 66 patients undergoing spinal surgery for excision of intradural pathology. Prior to dural incision, intraoperative standard B-mode images have been acquired using curved linear array transducer (4D micro-convex endocavitary transducer, 5–9 MHz ultrasound probe, RIC5-9 curved linear array volumetric real time 3D probe, GE Healthcare). The identification of adjacent structures and tumor borders as well as verification of the bony exposure were major goals.

Results: In all 66 patients, the intradural pathology has been visualized by ioUS. Further extension of the bony removal prior to dura opening was necessary in 3 cases according to ioUS. However, ioUS could not identify the borders of 14 (21%) pathologies sufficiently. In 12 of these cases, the visual identification of a tumor border in microscope was also not possible intraoperatively. Arachnoid layers, dentate ligament and hemorrhage were pointed out easily by ioUS. Gross total resection was reached in 77% of the cases according to postoperative magnetic resonance imaging and macroscopic survey. Because of the eloquent location and changes in electrophysiological monitoring, 23% of the tumors were resected partially.

Conclusion: We demonstrate the intraoperative applicability of ioUS in spinal surgery. Although gross total resection is still limited by eloquent location of intramedullary pathologies, the various ioUS modalities should be utilized for better tumor delineation. The ease of assessment of the bony exposure and detection of intraspinal pathology by ioUS presupposes its applicability in spinal surgery.