Surgical Navigation Improves Renal Parenchyma Volume Preservation in Robot-Assisted Partial Nephrectomy: A Propensity Score Matched Comparative Analysis.

PURPOSE: We investigated the relationship between the surgical navigation system and postoperative parenchyma preservation volume, and assessed the feasibility of image guided surgery in robot-assisted partial nephrectomy. MATERIALS AND METHODS: We developed surgical navigation with registration between real-time endoscopic images using 3-dimensional virtual reality models for robot-assisted partial nephrectomy. Surgical outcomes of 44 (nonsurgical navigation group) and 102 (surgical navigation group) patients between June 2013 and December 2018 were retrospectively analyzed. To adjust for potential baseline confounders propensity score matching (1:1) was performed. Renal parenchymal preservation rate and extraparenchymal volume with a tumor including functional and oncological outcomes ("trifecta" defined as warm ischemia time of less than 25 minutes, no complications and negative surgical margins; "pentafecta" defined as trifecta plus greater than 90% preservation of estimated glomerular filtration rate at 12 months postoperatively and chronic kidney disease up staging) were evaluated using volumetric analysis and compared. RESULTS: After matching, 42 patients were allocated to each group. No significant differences in baseline characteristics; complications; and intraoperative, trifecta and pentafecta outcomes were observed between the 2 groups. Pathological T stages were significantly different between the groups (T1a/T1b/T2a or more 25/10/7 in the nonsurgical navigation group vs 35/7/0 in the surgical navigation group, p=0.003). Extraparenchymal volumes and parenchyma volume preservation rates were significantly higher in the surgical navigation group (21.4 vs 17.2 ml, p=0.041 and 83.5% vs 90.0%, p=0.042, respectively). Surgical navigation was positively associated with improved parenchyma preservation volume (p=0.003). CONCLUSIONS: Surgical navigation preserves renal parenchyma in robot-assisted partial nephrectomy and may contribute to improvement in postoperative renal function.

Template-guided implantation of the Bonebridge: clinical experience.

The surgical procedure for Bonebridge implantation cannot be done in some cases without exposing the dura mater or sigmoid sinus. Surgical simulation technology can help to identify such difficulties prior to surgery and be used to clarify the optimal location and orientation of the device to be implanted. However, there has not been a simple strategy to drill the temporal bone at exactly the same location as that simulated on the computer. Based on our previous development of the surface template-assisted marker positioning (STAMP) method for performing image-guided otologic surgery, we recently developed a noninvasive guiding method, the BB-STAMP method, for performing image-guided Bonebridge implantation. Three patients underwent Bonebridge implantation at our surgical center during the years of 2013-2014. The authors in the simulation center supported the surgery using the BB-STAMP method. The time and effort required to prepare for the surgery were evaluated. In addition, a postoperative analysis was performed to assess the accuracy of placing the device in the planned location. The BB-STAMP method enabled the surgeon to precisely replicate the computer simulation in the real patient with submillimetric accuracy without complexity. Thus, the use of experienced and elaborative simulation coupled with the creation of a tailor-made three-dimensional template (BB-STAMP) enables surgeons to perform quick, precise and safe surgical procedures at distant institutions.

Asymmetrical surface scanning registration for image-guided otologic surgery: A phantom study.

OBJECTIVE: To develop a registration procedure to achieve a higher degree of registration accuracy in image-guided otological surgery, paying particular attention to the registration centroid. METHODS: A head phantom was used to measure the target registration error (TRE) at measurement points at various depth from the surface of the head. The surface-matching registration was performed using a commercially available surgical navigation system. We registered the phantom using only one ear of either side (right 100% - left 0%, or right 0% - left 100%) or using both ears with variable ratios (right 75% - left 25%, right 50% - left 50%, or right 25% - left 75%). RESULTS: The overall TRE was the smallest when registration was performed equally on both sides. However, the TRE at 20-50 mm from the surface was the smallest when the fiducial points for the registration were collected asymmetrically at a ratio of 75:25 and weighed heavier on the operating side, and this difference was statistically significant. CONCLUSION: The accuracy of image-guided surgery can be improved by carefully planning the registration procedure without changing the procedure itself. Accurate image-guided surgery at the middle and inner ear was achieved using 75% of the point cloud for the operating side and 25% of that for the opposite side for the registration.

Assessment of surgical skills by using surgical navigation in robot-assisted partial nephrectomy.

PURPOSE: To assess surgical skills in robot-assisted partial nephrectomy (RAPN) with and without surgical navigation (SN). METHODS: We employed an SN system that synchronizes the real-time endoscopic image with a virtual reality three-dimensional (3D) model for RAPN and evaluated the skills of two expert surgeons with regard to the identification and dissection of the renal artery (non-SN group, n = 21 [first surgeon n = 9, second surgeon n = 12]; SN group, n = 32 [first surgeon n = 11, second surgeon n = 21]). We converted all movements of the robotic forceps during RAPN into a dedicated vocabulary. Using RAPN videos, we classified all movements of the robotic forceps into direct action (defined as movements of the robotic forceps that directly affect tissues) and connected motion (defined as movements that link actions). In addition, we analyzed the frequency, duration, and occupancy rate of the connected motion. RESULTS: In the SN group, the R.E.N.A.L nephrometry score was lower (7 vs. 6, P = 0.019) and the time to identify and dissect the renal artery (16 vs. 9 min, P = 0.008) was significantly shorter. The connected motions of inefficient "insert," "pull," and "rotate" motions were significantly improved by SN. SN significantly improved the frequency, duration, and occupancy rate of connected motions of the right hand of the first surgeon and of both hands of the second surgeon. The improvements in connected motions were positively associated with SN for both surgeons. CONCLUSION: This is the first study to investigate SN for nephron-sparing surgery. SN with 3D models might help improve the connected motions of expert surgeons to ensure efficient RAPN.

Preoperative simulation unveiled undetected surgical difficulties in a case of cochlear implantation.

We herein report a case in which extensive preparation changed a difficult-to-treat patient into an easy one. We performed a revision cochlear implantation on a patient whose first procedure had been aborted due to unidentified difficulties. During a series of thorough three-dimensional simulations, we found that the patient in question had a normal cochlea but the cochlea was placed in an unusual position and orientation. This condition is difficult to detect on standard preoperative radiographic images. Through this simulation, we were able to propose a surgical plan to avoid making the same mistakes as the first surgeon. We present this case not as a rare difficult case of an unfortunate patient but instead emphasise the importance of performing surgical simulation and looking for non-obvious difficulties. This case is an example of the success that can be achieved with such extensive preparation.

An effective visualization technique for depth perception in augmented reality-based surgical navigation.

BACKGROUND: Depth perception is a major issue in augmented reality (AR)-based surgical navigation. We propose an AR and virtual reality (VR) switchable visualization system with distance information, and evaluate its performance in a surgical navigation set-up. METHODS: To improve depth perception, seamless switching from AR to VR was implemented. In addition, the minimum distance between the tip of the surgical tool and the nearest organ was provided in real time. To evaluate the proposed techniques, five physicians and 20 non-medical volunteers participated in experiments. RESULTS: Targeting error, time taken, and numbers of collisions were measured in simulation experiments. There was a statistically significant difference between a simple AR technique and the proposed technique. CONCLUSIONS: We confirmed that depth perception in AR could be improved by the proposed seamless switching between AR and VR, and providing an indication of the minimum distance also facilitated the surgical tasks.

Semi-manual mastoidectomy assisted by human-robot collaborative control - A temporal bone replica study.

OBJECTIVE: To develop an otological robot that can protect important organs from being injured. METHODS: We developed a five degree-of-freedom robot for otological surgery. Unlike the other robots that were reported previously, our robot does not replace surgeon's procedures, but instead utilizes human-robot collaborative control. The robot basically releases all of the actuators so that the surgeon can manipulate the drill within the robot's working area with minimal restriction. When the drill reaches a forbidden area, the surgeon feels as if the drill hits a wall. RESULTS: When an engineer performed mastoidectomy using the robot for assistance, the facial nerve in the segmented region was always protected with a more than 2.5mm margin, which was almost the same as the pre-set safety margin of 3mm. CONCLUSION: Semi-manual drilling using human-robot collaborative control was feasible, and may hold a realistic prospect of clinical use in the near future.

Registration using 3D-printed rigid templates outperforms manually scanned surface matching in image-guided temporal bone surgery.

PURPOSE: Image-guided surgery (IGS) for otological procedures requires minimal invasiveness and a high degree of accuracy. We have recently developed a noninvasive registration method, the Surface Template-Assisted Marker Positioning (STAMP) method, which uses a rigid template of the surface of the temporal bone. However, the STAMP method is not applicable when the bony surface is not exposed, such as in endoscopic surgery. Thus, we extended our research to apply the STAMP method onto the skin and tested its feasibility in this study. METHODS: We designed a phantom made of a rigid box and soft material for the study. The target registration error (TRE) was measured at preset measuring points in the phantom. We modified the STAMP method to be applicable for use on the skin around the ears (S-STAMP). The same phantom was also registered using the conventional, manually scanned surface matching method. We compared the TRE after the different registration methods. RESULTS: The TRE after the S-STAMP registration method was significantly smaller than that of the conventional surface matching method at all error measurement points in the phantom. However, the TRE after the S-STAMP registration method was significantly larger than that of paired point registration using invasive fiducial markers. CONCLUSIONS: The S-STAMP method using a rigid template on the soft surface yields a significantly smaller TRE than that of conventional, manually scanned surface matching registration. This strategy provides an alternative option to improve the accuracy of IGS without loading patients with additional invasive procedures.

A surgical navigation system for guiding exact cochleostomy using auditory feedback: a clinical feasibility study.

In cochlear implantation (CI), the insertion of the electrode array into the appropriate compartment of the cochlea, the scala tympani, is important for an optimal hearing outcome. The current surgical technique for CI depends primarily on the surgeon's skills and experience level to achieve the correct placement of the electrode array, and the surgeon needs to confirm that the exact placement is achieved prior to completing the procedure. Thus, a surgical navigation system can help the surgeon to access the scala tympani without injuring important organs in the complex structure of the temporal bone. However, the use of a surgical microscope has restricted the effectiveness of the surgical navigation because it has been difficult to deliver the navigational information to the surgeon from outside of the surgeon's visual attention. We herein present a clinical feasibility study of an auditory feedback function developed as a computer-surgeon interface that can guide the surgeon to the preset cochleostomy location. As a result, the surgeon could confirm that the drilling point was correct, while keeping his or her eyes focused on the microscope. The proposed interface reduced the common frustration that surgeons experience when using surgical navigation during otologic surgeries.

Image-guided placement of the Bonebridge™ without surgical navigation equipment.

PURPOSE:    Most of the current Bonebridge surgeries undergo preoperative simulation planning in a computer. However, surgeons usually use the landmarks on the bone surface to determine the location where to implant the device, using the simulation image in the computer only as a reference (conventional method). We developed an image-guided method for precisely replicating simulation surgery upon performing Bonebridge implantation. METHODS:    Based on our previous development of the surface template-assisted marker positioning (STAMP) method for performing image-guided otologic surgery, we fabricated templates that fit only at the designated location on the patient's temporal bone surface. The Bonebridge STAMP (BB-STAMP) plate shows the exact location where to start drilling. The BB-STAMP was also combined with a perforator-guiding sleeve, so that the location, direction and depth of the cylindrical well could be precisely replicated as simulated. We also created a STAMP plate for confirmation that fits only after sufficient drilling at the correct location is finished. To evaluate the proposed methods, we performed simulation surgery on four cadaveric temporal bones and their 12 replicas (three each for four bones). The time used and the degree of mismatch between the simulated location and the drilled location were compared. RESULTS:    A feasibility study was successfully conducted using the proposed BB-STAMP methods and the conventional method. The amount of time required for the procedure did not differ significantly between the surgical methods, although using the BB-STAMP and perforator guide was always quicker. The degree of mismatch between the simulation and resected models had tendency to be smaller when the surgery was guided by the BB-STAMP with or without a perforator guide, although the difference was not statistically significant. CONCLUSIONS:    The proposed BB-STAMP is a promising method for replicating exactly what is performed during simulation without using a surgical navigation system.

A preregistered STAMP method for image-guided temporal bone surgery.

OBJECTIVES: Image-guided otological surgeries require minimal invasiveness and high accuracy, and these two factors usually compete with each other. Our recently developed registration method, called the STAMP method, showed minimal invasiveness with accuracy comparable to that of the current more invasive registration methods used in image-guided temporal bone surgery. However, surgeons perceived the STAMP method as complex and time-consuming. METHODS: We modified our STAMP method to further simplify the surgeon's tasks in the operating room. We attached an optical tracking target on the STAMP plate and registered the plate in an IGS system before surgery, outside the operating room. The registration was completed in the operating room by finishing the final simple task, which was to hold the preregistered STAMP plate still on the patient's temporal bone. We tested this modified preregistered STAMP method in simulation surgery and actual surgeries. The registration times and errors of the STAMP method and preregistered STAMP method were compared. RESULTS: The proposed new preregistered STAMP method significantly reduced the registration time in the operating room without compromising the registration accuracy. CONCLUSIONS: The preregistered STAMP method significantly improved the original STAMP method in terms of time and convenience. It is now considered to be one of the easiest and quickest registrations for image-guided temporal bone surgery. Because most of the critical processes of registration can be completed in the laboratory, the registration task in the operating room is therefore greatly simplified, thus allowing surgeons to concentrate more on the surgery itself.

A clinical experience of 'STAMP' plate-guided Bonebridge implantation.

CONCLUSION: The surface template-assisted marker positioning (STAMP) method is useful for successful Bonebridge™ (BB) implantation on a planned site while avoiding dangerous positions. OBJECTIVES: To confirm the usefulness of the STAMP method for the safe operation of BB. METHODS: From a patient's temporal bone CT data, a guide plate and confirmation plate were generated by the STAMP method. The guide plate is used to mark the correct place for implantation, while the confirmation plate lets us know the correct angle and depth of the hole. RESULTS: With the guide plate, the correct place for BB implantation was easily found. The hole was made to be an appropriate size with the confirmation plate while exposing only a small part of sigmoid sinus as simulated. Finally, the BB implant was successfully placed exactly at the planned site.

Navigation for cochlear implantation.

A cochlear implant is an artificial sensory organ for patients with severe to profound hearing loss who have little benefit from hearing aids. The fact that more patients with previous temporal bone surgery or cranial malformations are receiving cochlear implants implies that the number of atypical cochlear implantation will continue to grow. Surgical navigation, or image-guided surgery may be helpful for surgeons who perform atypical surgeries. We report our research on an image-guided system specifically designed for otologic surgery with an improved surgeon-computer interface.

Warning navigation system using real-time safe region monitoring for otologic surgery.

PURPOSE: We developed a surgical navigation system that warns the surgeon with auditory and visual feedback to protect the facial nerve with real-time monitoring of the safe region during drilling. METHODS: Warning navigation modules were developed and integrated into a free open source software platform. To obtain high registration accuracy, we used a high-precision laser-sintered template of the patient's bone surface to register the computed tomography (CT) images. We calculated the closest distance between the drill tip and the surface of the facial nerve during drilling. When the drill tip entered the safe regions, the navigation system provided an auditory and visual signal which differed in each safe region. To evaluate the effectiveness of the system, we performed phantom experiments for maintaining a given safe margin from the facial nerve when drilling bone models, with and without the navigation system. The error of the safe margin was measured on postoperative CT images. In real surgery, we evaluated the feasibility of the system in comparison with conventional facial nerve monitoring. RESULTS: The navigation accuracy was submillimeter for the target registration error. In the phantom study, the task with navigation ([Formula: see text] mm) was more successful with smaller error, than the task without navigation ([Formula: see text] mm, [Formula: see text]). The clinical feasibility of the system was confirmed in three real surgeries. CONCLUSIONS: This system could assist surgeons in preserving the facial nerve and potentially contribute to enhanced patient safety in the surgery.

Cochlear implantation assisted by noninvasive image guidance.

OBJECTIVE: We recently developed a new noninvasive registration method for image-guided otologic surgery (STAMP method). We investigated the benefit and potential drawback of our new method in clinical application and tested the feasibility of routine image-guided surgery. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral university hospital. PATIENTS: Forty-six cases (45 patients) that underwent cochlear implantation in Kyushu University Hospital during the period of 2007 and 2010 were informed of the option to use navigated surgery. INTERVENTION: Twenty-five cochlear implantations were performed using STAMP-registered image-guided surgery. MAIN OUTCOME MEASURE: The error of image-guided surgery and time of surgery were collected and analyzed. RESULTS: STAMP method offered serviceable accuracy in 18/25 cochlear implantations. The learning curve suggested that the accuracy is at least stabilizing, if not improving, and the success rate is expected to rise. Time of cochlear implant surgery was not significantly extended by the use of image guidance. CONCLUSION: STAMP method had comparable errors with minimal invasiveness. Our new method potentially enables routine use of image-guided surgery.