Ommaya reservoir with ventricular catheter placement for chemotherapy with frameless and pinless electromagnetic surgical neuronavigation

Background Accuracy in Ommaya reservoir catheter placement is critical to chemotherapy infusion. Most frameless image guidance is light emitting diode (LED) based, requiring a direct line of communication between instrument and tracker, limiting freedom of instrument movement within the surgical field. Electromagnetic neuronavigation may overcome this challenge. Objective To compare Ommaya reservoir ventricular catheter placement using electromagnetic neuronavigation to LED-based optical navigation, with emphasis on placement accuracy, operative time and complication rate. Methods Twenty-eight patients who underwent placement of Ommaya reservoirs at our institution between 2010 and 2014 with either electromagnetic (12 patients) or optical neuronavigation (16 patients) were retrospectively reviewed. Results Half of the patients were male. Their mean age was 56 years (range 28–87 years). Accuracy and precision in catheter tip placement at the target site (foramen of Monro) were both higher ( p =0.038 and p =0.043, respectively) with electromagnetic neuronavigation. Unintended placement of the distal catheter contralateral to the target site occurred more frequently with optical navigation, as did superior or inferior positioning by more than 5mm. Mean operative times were shorter ( p =0.027) with electromagnetic neuronavigation (43.2min) than with optical navigation (51.0min). There were three complications (10.7%) – one case each of cytotoxic edema, post-operative wound infection, and urinary tract infection. The rate of complication did not differ between groups. Conclusion In contrast with optical neuronavigation, frameless and pinless electromagnetic image guidance allows the ability to track instrument depth in real-time. It may increase ventricular catheter placement accuracy and precision, and decrease operative times.