Peter Milos

A new microsurgical instrument – a suction tube combined with a microdissector

A microsurgical suction tube with an attached ball probe has been developed. It functions as a microdissector when the ball probe is in its extended position, creating a larger working field than an ordinary sucker. When the ball probe is in the repose position, it does not interfere with the suction capacity, and the suction tube serves as a regular sucker. By adding the properties of the microdissector to the suction tube, dissection of exquisitely fine and subtle structures, including arachnoidal membranes, is facilitated. The ball probe is easily dismantled from the suction tube and the whole instrument conveniently cleaned.

Neurosurgical patterns of care for diffuse low-grade gliomas in Sweden between 2005 and 2015

Abstract Background In the last decade, increasing evidence has evolved for early and maximal safe resection of diffuse low-grade gliomas (LGGs) regarding survival. However, changes in clinical practice are known to occur slowly and we do not know if the scientific evidence has yet resulted in changes in neurosurgical patterns of care. Methods The Swedish Brain Tumor Registry was used to identify all patients with a first-time histopathological diagnosis of LGG between 2005 and 2015. For analysis of surgical treatment patterns, we subdivided assessed time periods into 2005-2008, 2009-2012, and 2013-2015. Population-based data on patient and disease characteristics, surgical management, and outcomes were extracted. Results A total of 548 patients with diffuse World Health Organization grade II gliomas were identified: 142 diagnosed during 2005-2008, 244 during 2009-2012, and 162 during 2013-2015. Resection as opposed to biopsy was performed in 64.3% during 2005-2008, 74.2% during 2009-2012, and 74.1% during 2013-2015 (P = .08). There was no difference among the 3 periods regarding overall survival (P = .11). However, post hoc analysis of data from the 4 (out of 6) centers that covered all 3 time periods demonstrated a resection rate of 64.3% during 2005-2008, 77.4% during 2009-2012, and 75.4% during 2013-2015 (P = .02) and longer survival of patients diagnosed 2009 and onward (P = .04). Conclusion In this nationwide, population-based study we observed a shift over time in favor of LGG resection. Further, a positive correlation between the more active surgical strategy and longer survival is shown, although no causality can be claimed because of possible confounding factors.

Optical guidance for stereotactic brain tumor biopsy procedures: preliminary clinical evaluation (Conference Presentation)

In the routine of stereotactic biopsy on suspected tumors located deep in the brain or patients with multiple lesions, tissue samples are harvested to determine the type of malignancy. Biopsies are taken from pre-calculated positions based on the preoperative radiologic images susceptible to brain shift. In such cases the biopsy procedure may need to be repeated leading to a longer operation time. To provide guidance for targeting diagnostic tumor tissue and to avoid vessel rupture on the insertion path of the tumor, an application specific fiber optic probe was developed. The setup incorporated spectroscopy for 5-aminolevulinic acid induced protopophyrin IX (PpIX) fluorescence in the tumor and laser Doppler for measuring microvascular blood flow which recorded backscattered light (TLI) at 780 nm and blood perfusion. The recorded signals were compared to the histopathologic diagnosis of the tissue samples (n=16) and to the preoperative radiologic images. All together 146 fluorescence and 276 laser Doppler signals were recorded along 5 trajectories in 4 patients. On all occasions strong PpIX fluorescence peaks were visible during real-time guidance. Comparing the gliotic tumor marginal zone with the tumor, the PpIX (51 vs. 528 a.u., [0-1790], p < 0.05) was higher and TLI (2.9 vs. 2.0 a.u., [0-4.1], p < 0.05) was lower in tumor. The autofluorescence (104 vs.70 a.u., [0-442], p > 0.05) and blood perfusion (8.3 vs. 17 a.u., [0-254], p > 0.05) were not significantly different. In conclusion, the optical guidance probe made real-time tumor detection and vessel tracking possible during the stereotactic biopsy procedures. Moreover, the fluorescence and blood perfusion in the tumor could be studied at controlled positions in the brain and the tumor.