Laparoscopic Navigation System Research Articles

Initial Report: A Novel Intraoperative Navigation System for Laparoscopic Liver Resection Using Real-Time Virtual Sonography

Recent progress in navigation has revealed problems involving non-rigid registration for hepatic surgery. With the increasing popularity of laparoscopic liver surgery, a new laparoscopic navigation system is necessary. This study involved an in-vitro demonstration of a 3-dimensional printer model and in vivo demonstration in four patients. For the in vitro examination, a position detecting unit attached at 33 cm and 13 cm distance conditions from the tip of the electrocautery was examined eight times at the marked points on the liver surface eight times respectively. The differences between the simulation and the authentic dissecting plane were conventionally investigated in vivo. In vitro, the errors of the 33 cm and 13 cm distance model were7.8 ± 3.5 mm (mean ± SD), and 3.3 ± 1.0 mm, respectively. The mean differences of the dissection plane were within 10 mm. The potentiality and safety of the novel navigation system was confirmed, although further investigation is recommended.

Ultrasound-navigated laparoscopic liver surgery

Purpose: Actually the technique of laparoscopic liver resection has been mostly performed in high volume centers with hepatobiliary and laparoscopic expertise in highly selected patients. For better intraoperative visualization we developed a laparoscopic navigation system (LapAssistent) to register preoperative 3D-CT or MRI Scans to the intraoperative field. Intraoperative the laparoscopic instruments were connected to the LapAssistent with real-time ultrasound B-Mode screen and real-time laparoscopic video screen. Material and methods: Preoperative planning data were performed by Fraunhofer MeVis Bremen/Germany. After calibration of the system including camera, laparoscopic instruments and the intraoperative ultrasound probe we registered the surface of the liver. By the navigated ultrasound the preoperatively planned resection plane has then been overlain with the patient's liver. The laparoscopic navigation system has been able to use under sterile conditions and it has been possible to register and visualize the preoperative planned resection plane. Results: After experimental development of the navigation system we started in January 2010 with the clinical use of navigation-assisted laparoscopic liver surgery. We report about the technical aspects of the navigation system and the clinical use in three cases. One patient with a large benign adenoma was resected by laparoscopic navigated atypical liver resection. By a metastatic mammacarcinom one thermal ablation was done and in a third case two atypical resections in the right liver lobe. Conclusion: By the navigated ultrasound the preoperatively planned resection plane has then been overlain with the patient's liver. The laparoscopic navigation system has been able to use under sterile conditions and it has been possible to register and visualize the preoperative planned resection plane. These first results now have to be proven in a larger patient collective and we performed a German wide multicenter study (ProNavic I).

Laparoscopic Navigated Liver Resection: Technical Aspects and Clinical Practice in Benign Liver Tumors

Laparoscopic liver resection has been performed mostly in centers with an extended expertise in both hepatobiliary and laparoscopic surgery and only in highly selected patients. In order to overcome the obstacles of this technique through improved intraoperative visualization we developed a laparoscopic navigation system (LapAssistent) to register pre-operatively reconstructed three-dimensional CT or MRI scans within the intra-operative field. After experimental development of the navigation system, we commenced with the clinical use of navigation-assisted laparoscopic liver surgery in January 2010. In this paper we report the technical aspects of the navigation system and the clinical use in one patient with a large benign adenoma. Preoperative planning data were calculated by Fraunhofer MeVis Bremen, Germany. After calibration of the system including camera, laparoscopic instruments, and the intraoperative ultrasound scanner we registered the surface of the liver. Applying the navigated ultrasound the preoperatively planned resection plane was then overlain with the patient's liver. The laparoscopic navigation system could be used under sterile conditions and it was possible to register and visualize the preoperatively planned resection plane. These first results now have to be validated and certified in a larger patient collective. A nationwide prospective multicenter study (ProNavic I) has been conducted and launched.

Design and development of adapters for electromagnetic trackers to perform navigated laparoscopic radiofrequency ablation

BackgroundLaparoscopic radiofrequency ablation (RFA) is an accepted approach to treat unresectable liver tumours distinguishing itself from other techniques by combining minimal invasiveness and the advantages of a surgical approach. The major task of laparoscopic RFA is the accurate needle placement to achieve complete tumour ablation. The use of an ultrasound-based, laparoscopic online-navigation system could increase the safety and accuracy of punctures. To connect such a system with the laparoscopic ultrasound (LUS) transducer or the RFA needle especially designed adapters are needed. In this article we present our first experiences and prototypes for different sterilizable adapters for an electromagnetic navigation system for laparoscopic RFA.MethodsAll adapters were constructed with the help of a standard 3D CAD software. The adapters were built from medical stainless steel alloys and polyetherketone (PEEK). Prototypes were built in aluminium and polyoxymethilen (POM). We have designed and developed several adapters for the connection of electromagnetical tracking systems with different RFA needles and a laparoscopic ultrasound transducers.ResultsBased on earlier experiences of the initial version of the adapter, sterilisable adapters have been developed using biocompatible materials only. After short introduction, the adapters could be mounted to the laparoscopic ultrasound probe and the RFA needle under sterile conditions without any difficulties. Laboratory tests showed no disturbance of laparoscopic navigation system by the adapters. Anatomic landmarks in the liver could be safely reached. The adapters showed good feasibility, ergonomics, sterilizability and stability.ConclusionThe development of usable adapters is the prerequisite for accurate tracking of a RFA needle for laparoscopic navigation purposes as well as 3D navigated ultrasound data acquisition. We designed, tested and used different adapters for the use of a laparoscopic navigation system for the improvement of laparoscopic RFA.