Image guided prostate biopsy. MR segmented prostate (red) and tumor suspect region (blue) fused with live transrectal ultrasound. Biopsy needle inserted according to planed biopsy corridor (green/gray)
Tablet Computer Assisted Nephrostomy
To place nephrostomy catheter or to perform percutaneous nephrolithotomy the application guides the puncture of the collecting system [8, 9]. Preoperative CT scan in prone position on PCNL cushion is performed while four to five colored skin stickers where already placed around the target area serving as navigation aids. Intraoperatively, the tablet computer’s camera had to film navigation aids and puncture needle. Via WiFi a server calculates navigation information and sends data back for display on screen of the used tablet computer in real time (Fig. 72.2). The surgeon gets an augmented reality image visualizing kidney, collecting system, predefined target structures and puncture corridor. So performed kidney puncture showed reduction of radiation exposure.
Tablet computer assisted nephrostomy. Four navigation aids are attached to patient’s skin lying in prone position during puncturing the collecting system. Tablet computer shows augmented reality image superimposing kidney, vessels, renal calyces and pelvis underneath patient’s skin
The introduced system uses needle shaped navigation aids . Their shafts and the 3D configuration of prostates boarder and especially the neurovascular bundles are identified via intraoperative TRUS. The colored heads of the needles are used for marker-based tracking (Fig. 72.3). For the first steps of surgery, in particular during apical dissection, it could be shown significant lower rate of positive margins with only minimal longer OR time. Due to deformation and rotation of the prostate, the systems use is limited to first dissecting steps.
Navigated Prostatectomy. Plain laparoscopic prostatectomy image with four navigation aids inserted into the prostate (left). Augmented reality image (right) with navigation aids (yellow), prostate’s boarder (green), left neurovascular bundle (blue), urethra (green) and biopsy positive region superimposed
Hybrid Fluoroscopy Assisted/Navigated Partial Nephrectomy
Based on MR or CT data, 3D segmentation of kidney, renal vessels, renal tumor and the surrounding structures are created preoperatively. For marker based tracking a Dyna-CT (Siemens Medical Solutions, Erlangen, Germany) acquires intraoperative anatomy and navigation aids for augmented reality visualization [5, 11, 12]. Furthermore, with the help of fluoroscopy deformed anatomy during dissection can be registered (Fig. 72.4).