Flexible Fiber CO2 Laser in Microsurgical Treatment of Intraventricular Tumors: Usefulness and Limitations.

OBJECTIVE: To assess usefulness and limitations of flexible fiber carbon dioxide (CO2) laser in the microsurgical treatment of intraventricular tumors. METHODS: We reviewed a series of 9 patients treated with microsurgical resection of intraventricular tumors using a flexible fiber CO2 laser. The lesions involved the third ventricle (8) and the frontal horn of the right lateral ventricle (1). Histology revealed 6 craniopharyngiomas, 1 pituitary macroadenoma, 1 subependymoma, and 1 neurocytoma. In all cases, an interhemispheric transcallosal approach was performed. The laser was used during callosotomy, fornix column sectioning, tumor debulking, and to facilitate tumor dissection. We used a 5-tiered score system to assess laser's efficacy in each surgical step (approach, dissection, debulking): grade 1: laser was not at all helpful, grade 5: laser was extremely helpful. Limits of the instrument also are discussed. RESULTS: Gross total resection was achieved in 6 cases and subtotal resection in the remaining 3. Three patients had pulmonary complications treated without clinical sequelae. No laser-related complication was described. Mean utility score observed was 4.2 (range 3-5) during approach, 2.8 (range 2-4) during tumor dissection; and 3.3 (range 2-5) during tumor debulking. Main limits were low hemostatic effect and inefficiency versus calcified and highly vascularized tumors. CONCLUSIONS: The CO2 laser proved to be a useful and safe tool that could be used for intraventricular pathology; its design is suitable for narrow surgical corridors like interhemispheric fissure and foramen of Monro; its main utility is the ability to create precise and relatively bloodless cut (callosotomy, tumor debulking); low hemostatic effect is its main limit.

Ultrasound-guided brain surgery: echographic visibility of different pathologies and surgical applications in neurosurgical routine.

BACKGROUND: The use of intraoperative ultrasound (iUS) has increased in the last 15 years becoming a standard tool in many neurosurgical centers. Our aim was to assess the utility of routine use of iUS during various types of intracranial surgery. We reviewed our series to assess ultrasound visibility of different pathologies and iUS applications during the course of surgery. MATERIALS AND METHODS: This is a retrospective review of 162 patients who underwent intracranial surgery with assistance of the iUS guidance system (SonoWand). Pathologic categories were neoplastic (135), vascular (20), infectious (2), and CSF related (5). Ultrasound visibility was assessed using the Mair classification, a four-tiered grading system that considers the echogenicity of the lesion and its border visibility (from 0 to 3; grade 0, pathology not visible; grade 3, visible with clear border with normal tissue). iUS applications included lesion localization, approach planning to deep-seated lesions, and lesion removal. RESULTS: All pathologies were visible on iUS except one aneurysm. On average, extra-axial tumors were identified more easily and had clearer limits compared to intra-axial tumors (extra-axial 17% grade 2, 83% grade 3; intra-axial 5.5% grade 1, 46.5% grade 2, 48% grade 3). iUS provided precise and safe transcortical trajectories to deep-seated lesions (71 patients; tumors, hemangiomas, ICHs); iUS was judged to be less useful to approach skull base tumors and aneurysms. iUS was used to judge extent of resection in 152 cases; surgical artifacts reduced sonographic visibility in 25 cases: extent of resection was correctly checked in 127 patients (53 gliomas, 15 metastases, 39 meningiomas, 4 schwannomas, 4 sellar region tumors, 6 hemangiomas, 3 AVMs, 2 abscesses). CONCLUSIONS: iUS was highly sensitive in detecting all types of pathology, was safe and precise in planning trajectories to intraparenchymal lesions (including minimally mini-invasive approaches), and was accurate in checking extent of resection in more than 80% of cases. iUS is a versatile and feasible tool; it could improve safety and its use may be considered in routine intracranial surgery.