Navigation Protocol Research Articles

Navigation and non-navigation CT scan of the sinuses: comparison of the effective doses of radiation in children and adults

BackgroundThe advent of 3D navigation imaging has opened new borders to the endoscopic surgical approaches of naso-sinusal inflammatory and neoplastic disease. This technology has gained in popularity among otolaryngologists for endoscopic sinus and skull base surgeries in both adults and children. However, the increased tissue radiation required for data acquisition associated with 3D navigation protocols CT scans is a source of concern because of its potential health hazards. We aimed to compare the effective doses of radiation between 3D navigation protocols and standard protocols for sinus computed tomography (CT) scans for both the adult and pediatric population.MethodsWe performed a retrospective cohort study through electronic chart review of patients undergoing sinus CT scans (standard and 3D navigation protocols) from May 2019 to December 2019 using a Siemens Drive (VA62A) CT scanner. The effective dose of radiation was calculated in mSv for all exams. Average irradiation doses were compared using a Student’s T-Test or a Kruskall–Wallis test when appropriate.ResultsA total of 115 CT scans were selected for analysis, of which 47 were standard protocols and 68 were 3D navigation protocols CT scans. Among these, 31 exams were performed on children and 84 exams on adults. For the total population, mean effective dose in the non-navigation CT scans was 0.37 mSv (SD: 0.16, N = 47) and mean effective dose in the 3D navigation sinus CT group was 2.33 mSv (SD: 0.45, N = 68). The mean difference between the two groups was statistically significant 1.97 mSv (CI 95% − 2.1 to − 1.83; P < 0.0001). There was a sixfold increase in radiation with utilization of 3D navigation protocols. The ratio was identical when the pediatric as well as the adult subset of patients were analyzed.ConclusionIn our center, utilization of 3D navigation sinus CT protocols significantly increases radiation exposure. Otolaryngologists should be aware of this significant increase and should attempt to decrease the radiation exposure of their patients by limiting unnecessary scan orders and by evaluating 3D acquisition protocols locally with radiation physicists.Level of evidence: Level IV.Graphical

Abstract PO-272: COVID-19 adaptations to patient navigation services for follow-up colonoscopy after an abnormal fecal test result in a community health center setting

Abstract The PRECISE study tests the effectiveness of a targeted patient navigation program for follow-up colonoscopy after an abnormal fecal test result in a community health center setting. We present adaptations and mid-study learnings related to the COVID-19 pandemic. Colorectal cancer (CRC) screening by annual fecal immunochemical test (FIT) is an accessible and cost-effective strategy to lower CRC incidence and mortality. However, this mode of screening depends on follow-up colonoscopy after an abnormal FIT result to prevent CRC or find it in early, treatable forms. Unfortunately, almost half of patients with an abnormal FIT result fail to complete this essential screening component, negating any benefit of FIT screening. Patient navigation can provide much needed support for patients to complete a follow-up colonoscopy. PRECISE is a patient-randomized trial of patient navigation vs usual care for follow-up colonoscopy that will enroll 1,200 patients across 28 community health center clinics in Washington state (anticipated 37% Latinx). As part of the study, we trained a bilingual (English and Spanish) patient navigator using an intensive 8-week program, based on the New Hampshire Colorectal Cancer Screening Program. The program included multiday trainings on CRC health information, colonoscopy steps, patient navigator skills, the navigation protocol, data reporting; a full-day motivational interviewing training delivered by a professional trainer; and in-person meetings with schedulers at local gastroenterology (GI) offices. On March 13, 2020, study enrollment for PRECISE was suspended due to the COVID-19 pandemic during which time all non-urgent medical procedures, including colonoscopies, were canceled or delayed. We trained our patient navigator to outreach to all randomized patients for whom navigation was in process at the time of study suspension. We developed COVID-19-specific talking points, and the outreach protocol was modified to address colonoscopy scheduling delays. To-date, 252 patients have been randomized (124 to navigation and 128 to usual care). Navigator conversations with local GI offices revealed several COVID-related GI practice changes: the pre-procedure consultation is generally delivered as a telehealth (phone-based) visit and COVID-19 testing is required prior to the colonoscopy. Furthermore, many practices mandate the use of face masks by patients and their escorts, and prohibit escorts from accompanying the patient in the pre-procedure area. We adapted navigator messages to address fear and anxiety about getting medical care during the peak COVID-19 pandemic. This innovative clinical trial highlights the importance of patient navigation to improve CRC screening in community health centers and examines COVID-19 adaptions to the navigation intervention. Citation Format: Jamie Thompson, Jennifer Rivelli, Amanda Petrik, Jennifer Schneider, Neha Yadav, Hanna Dinh, Cindy Pulido, Shirley Mendez, DeeDee Torres, Lakshmi Penimarthi, Gloria Coronado. COVID-19 adaptations to patient navigation services for follow-up colonoscopy after an abnormal fecal test result in a community health center setting [abstract]. In: Proceedings of the AACR Virtual Conference: Thirteenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2020 Oct 2-4. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(12 Suppl):Abstract nr PO-272.

Viral Hepatitis and Human Immunodeficiency Virus Testing and Linkage to Care for Individuals Enrolled in an Opioid Treatment Program.

In the United States, many opioid treatment programs (OTPs) do not offer viral hepatitis (VH) or human immunodeficiency virus (HIV) testing despite high prevalence among OTP clients. We initiated an opt-out VH and HIV testing and linkage-to-care program within our OTP. All OTP intakes are screened for VH and HIV and evaluated for rescreening annually. A patient navigator reviews laboratory results and provides counseling in the OTP clinic. The medical record is queried to identify individuals with previously diagnosed, untreated VH or HIV. Navigation support is provided for linkage or relinkage to VH or HIV care. Between March 2018 and Februrary 2019, 532 individuals were screened for hepatitis C virus (HCV), 180 tested HCV antibody positive (34%), and 108 were HCV-ribonucleic acid (RNA) positive (20%). Sixty individuals were identified with previously diagnosed, untreated HCV. Of all HCV RNA+, 49% reported current injection drug use (82 of 168). Ninety-five individuals were seen by an HCV specialist (57% of HCV RNA+), 72 started treatment (43%), and 69 (41%) completed treatment. Individuals with primary care providers were most likely to start treatment. Four individuals were diagnosed with hepatitis B; 0 were diagnosed with HIV. The implementation of an OTP-based screening and navigation protocol has enabled significant gains in the identification and treatment of VH in this high prevalence setting.

Abstract B038: The effects of coaching and action planning on patient activation and quality of life in vulnerable cancer patients

Abstract Introduction: The American Cancer Society Patient Navigator Program assists high-need, vulnerable patients in overcoming nonmedical barriers to cancer care with the goal of improving treatment adherence, completion, and patient quality of life. Methods: In the last year, the American Cancer Society has been implementing a pilot program aimed at increasing the activation and quality of life of patients at 6 navigation program sites nationwide. The sites were selected based on patient need, geographic location, and cancer center type. Navigators completed a 7-part training series focusing on coaching and communication skills and slight modifications were made to the current lay navigation protocol, including addition of the Insignia Health Patient Activation Measure® (PAM®) Survey, a patient satisfaction survey, formal action planning with the patient, and follow-up on the action plan over a period of at least 3 visits. Results are measured by ability of the patient to achieve the set actions in the plan, ability of the patient to overcome or successfully manage nonmedical barriers to care, and change in the patient's activation score. The following results are from the 3 sites in phase 2 of implementation. Results: After 6 months of implementation, 419 patients have been enrolled in phase 2 of the program. Patients represent 6 different races with African American/Black (40%) and Hispanic/Latino (36%) being most common. Medicaid is the most common form of insurance (42%) and 79% of patients are either insured by Medicaid, Medicare + Medicaid (10%), or uninsured (27%). Patient diagnoses span 32 different cancer types. Early results show positive uptake of the program among navigators and patients with all navigators reporting utilization of new coaching-based training skills, and 95% of patients reporting creating an action plan with their navigator. After their first meeting with the navigator, patients rated their confidence the action plan would work at an average of 8.7/10. Initial patient reactions also indicate a high level of satisfaction with a 4.4/5 average score when asked how much they agreed with the statement: “The navigator made me feel better about my ability to manage my diagnosis and treatment.” 182 patients have completed at least one follow-up visit with the navigator in the first 6 months. These patients set 634 actions with navigators and progress has been made or achieved on 76% of these actions by the first formal follow-up visit. 29 patients have completed the full program with 78% of barriers overcome or successfully managed. 100% of patients completing the program also completed treatment, and the average PAM® score increased by +4.15 points. The project is still ongoing. Final results of the pilot are expected in late 2019. Conclusion: Navigation with coaching and action planning tailored to the patient's activation level is a successful method to assist vulnerable populations with overcoming nonmedical barriers to cancer care and increasing patient activation. Citation Format: Shelby S. Roberts, Dawn Wiatrek, Nicole Erb, Katherine Sharpe. The effects of coaching and action planning on patient activation and quality of life in vulnerable cancer patients [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr B038.

Navigable maps of structural brain networks across species.

Connectomes are spatially embedded networks whose architecture has been shaped by physical constraints and communication needs throughout evolution. Using a decentralized navigation protocol, we investigate the relationship between the structure of the connectomes of different species and their spatial layout. As a navigation strategy, we use greedy routing where nearest neighbors, in terms of geometric distance, are visited. We measure the fraction of successful greedy paths and their length as compared to shortest paths in the topology of connectomes. In Euclidean space, we find a striking difference between the navigability properties of mammalian and non-mammalian species, which implies the inability of Euclidean distances to fully explain the structural organization of their connectomes. In contrast, we find that hyperbolic space, the effective geometry of complex networks, provides almost perfectly navigable maps of connectomes for all species, meaning that hyperbolic distances are exceptionally congruent with the structure of connectomes. Hyperbolic maps therefore offer a quantitative meaningful representation of connectomes that suggests a new cartography of the brain based on the combination of its connectivity with its effective geometry rather than on its anatomy only. Hyperbolic maps also provide a universal framework to study decentralized communication processes in connectomes of different species and at different scales on an equal footing.

A Research on Energy Efficient Multiple Query Optimization in WSN

Back in the last couple of decades, wireless sensor networks (WSNs) have researched different applications are as from personalized, marketplace, armed forces, agriculture, and environment tracking into Web Things (IoT). The detector node's battery ability gets an essential issue if it isn't feasible to recharge or replace battery life. Inside this newspaper, we've reported that an extensive evaluate on hierarchical routing protocols predicated on single/multi-hop communicating and also for homogenous/heterogeneous WSNs together with a contrast of unique present protocols has been completed about the grounds of several elements which are energy intake, finishing delay, and load balancing, system equilibrium and scalability. A few facets which help determine the creation and the plan of navigation protocols may also be talked about. Some benefits and pitfalls of every protocol have were all appreciated

Zermelo's problem: Optimal point-to-point navigation in 2D turbulent flows using reinforcement learning.

To find the path that minimizes the time to navigate between two given points in a fluid flow is known as Zermelo's problem. Here, we investigate it by using a Reinforcement Learning (RL) approach for the case of a vessel that has a slip velocity with fixed intensity, Vs, but variable direction and navigating in a 2D turbulent sea. We show that an Actor-Critic RL algorithm is able to find quasioptimal solutions for both time-independent and chaotically evolving flow configurations. For the frozen case, we also compared the results with strategies obtained analytically from continuous Optimal Navigation (ON) protocols. We show that for our application, ON solutions are unstable for the typical duration of the navigation process and are, therefore, not useful in practice. On the other hand, RL solutions are much more robust with respect to small changes in the initial conditions and to external noise, even when Vs is much smaller than the maximum flow velocity. Furthermore, we show how the RL approach is able to take advantage of the flow properties in order to reach the target, especially when the steering speed is small.

Evaluation of the accuracy of volume navigation of sonography and computed tomography using a phantom

In case of superimpositions of gas in the gastrointestinal tract or the ribs, tissue changes well detectable on computed tomography (CT) cannot be identified sonographically in a number of cases. Combining ultrasonography and CT provides enhanced information compared to sole sonography and volume navigation may be used as an effective tool. Tissue samples easily and safely obtained under sonographic guidance are often necessary to confirm the diagnosis of a suspicious focus. In these cases, the spatial fusion of CT and sonography may also be employed for improved visualization of foci by eliminating superimposition of sonographic images which is a limitation of ultrasound. This study investigated the potential benefit and improved informative value of the fusion of CT and sonography in case of superimpositions and aimed at determining the registration method with the best accuracy. Sixteen models (10 models with peas [low contrast], 6 models with wooden spheres [high contrast] as round structures) were created. These models were examined by computed tomography and fused using 3 volume navigation protocols. Subsequently, volume-guided sonography was performed. The deviation of the specimens was measured. In total, 1026 measurements of the pea models and 648 measurements of the wooden sphere models were carried out. A fusion accuracy of 100 % was observed in 9.9 % (102/1026) resp. 9.9 % (64/648) of the models. In 85.4 % (876/1026) resp. 94.1 % (610/648) the deviation was < 5 mm and in 98.1 % (1006/1026) resp. 99.4 % (644/648) it was < 10 mm. The registration protocol in which all reference points were used for spatial fusion proved to be the most accurate CONCLUSION: The registration protocols for volume-guided ultrasound have sufficient biopsy accuracy to merge identical sites and provide the basis for improved volume-navigated biopsy sampling.

Maximizing Sacral Chordoma Resection by Precise 3-Dimensional Tumor Modeling in the Operating Room Using Intraoperative Computed Tomography Registration with Preoperative Magnetic Resonance Imaging Fusion and Intraoperative Neuronavigation: A Case Series

The primary treatment for patients with sacral chordoma is en bloc surgical resection with negative margins, which has been shown to reduce local recurrence and tumor-related morbidity. Here we describe the use of intraoperative neuronavigation using preoperative spine magnetic resonance imaging fused to intraoperative computed tomography (CT) to create 3-dimensional tumor reconstructions in the operating room for intraoperative identification of bone and soft-tissue margins for maximal safe tumor resection. A single-institution retrospective chart review was completed to encompass our experience of 6 consecutive patients who had sacral chordoma resections using our described navigation protocol. We collected data on patient demographics, previous surgeries, radiation therapy, preoperative examination, spinal levels involved, dural involvement, estimated blood loss, surgery time, tissue diagnosis, follow-up, postoperative examination, complications, and recurrence. Primary outcome was en bloc resection with negative margins as planned preoperatively. Negative surgical margins were achieved in 5 of 5 patients, who were preoperatively planned for en bloc resection with negative margins. The most common levels involved were S4-S5. All patients had a stable or improved neurologic examination after en bloc surgical resection. The average follow-up was 5.4 months ± 84.6 days. No patient had residual or recurrent tumor at last follow-up. Magnetic resonance imaging-CT fusion and 3-dimensional reconstruction techniques using an intraoperative CT scanner with image-guided navigation to aid preoperative planning and surgical resection of sacral chordomas are not well represented in the literature. This technique can be used for planning en bloc surgical resections and for more precisely identifying tumor margins intraoperatively.

The surgical combination between functional endoscopic sinus surgery and septorhinoplasty as a procedure for nasal polyps treatment: a case report

Background: Concurrent functional endoscopic sinus surgery (FESS) and septorhinoplasty are performed either for cosmetic reasons or for a medical condition. Many patients are not satisfied with their nose shape or have breathing problem. These problems usually occur as a result of nasal fracture, obstruction, chronic sinusitis, or polyps. Case presentation: The present case was a 45-year-old non-smoker Saudi male patient, who presented to King Abdullah medical city outpatient clinic with a history of chronic right nasal obstruction for 15 years. A computerized tomography scan of a paranasal sinus with navigation protocol showed bilateral nasal polyps. Endoscopic sinus surgery was performed under general anesthesia. After FESS surgery, rhinoplasty by inverted C-shape incision, and elevation of the flap was done. The patient showed improvement and was discharged with monthly follow-up. Conclusion: These procedures are safe and cost effective. It minimizes hospital stay and can treat functional complaints, such as nasal obstruction, sinus problems, septum deviation, and polyps’ removal at the same time.

SNP: A 1-Manifold Skeleton-Based Navigation Protocol in 3D Sensor Networks

We consider the navigation application of 3D sensor networks that can proactively guide the movement of internal users from potential dangers to a safe exit, where a 3D sensor network serves as a reactive system, instead of a monitoring tool or a medium of data acquisition. Most if not all existing efforts in this line concentrate on 2D cases only, and none of them can be readily applied to 3D sensor networks, posing it a non-trivial challenge to design an effective and light-weight navigation protocol in 3D sensor networks. In this paper, we propose the first location-free, distributed, and scalable navigation protocol that can provide a navigation route for users inside the 3D sensor network with guaranteed safety. More specifically, we formulate the navigation problem as the minimum cumulative exposure problem, and design SNP, a navigation protocol based on the so-called 1-manifold skeleton, which offers a safe path with a near-optimal cumulative exposure to dangers. Extensive simulations validate the effectiveness and efficiency of the proposed algorithm.

A novel approach to skull-base and orbital osteotomies through virtual planning and navigation.

Computer-assisted planning of osteotomy lines, coupled with navigation-guided performance of planned osteotomies, is a highly innovative approach to skull-base and orbital surgery. The aim of this pilot study is to provide an assessment of the accuracy of this novel approach in guiding the correct positioning of osteotomy lines in frontal, temporal, and orbital regions, defining the agreement between the spatial position of the planned and performed osteotomies. Fifteen patients with orbital, frontal sinus, and lateral skull-base diseases underwent virtual surgical planning. Osteotomies to access the orbit, frontal sinus, and lateral skull base were planned on computer tomography-based three-dimensional models. The planned osteotomies were reproduced on the operating field using a navigation system. The positions of the performed and planned osteotomies were compared. The results were described as the mean positional difference between planned and performed osteotomies and as Lin's concordance coefficient, and Bland-Altman limits of agreement were also defined. The overall mean difference was 0.719 mm (95% confidence interval [CI]: 0.472 to 0.965 mm). Overall, Lin's concordance coefficient was 0.997 (95% CI: 0.996 to 0.998), and overall Bland-Altman limits of agreement ranged from -1.407 to 2.844 mm. The smallest mean difference (0.587 mm, 95% CI: 0.244 to 0.931 mm) was calculated in the orbit group, whereas the highest mean difference (0.904 mm, 95% CI: 0.428 to 1.379 mm) was described in the lateral skull-base group. This study's results support the use of this novel planning and navigation protocol for guiding osteotomy in anterior and lateral skull-base surgery, providing a clinical validation of this technique. 4 Laryngoscope, 00:1-9, 2018 Laryngoscope, 129:823-831, 2019.

Two strategies used to solve a navigation task: A different use of the hippocampus by males and females? A preliminary study in rats

Abstract There is abundant research (both in rodents and in humans) showing that males and females often use different types of information in spatial navigation. Males prefer geometry as a source of information, whereas females tend to focus on landmarks (which are often near to a goal objects). However, when considering the role of the hippocampus, the research focuses primarily on males only. In the present study, based on Rodríguez, Torres, Mackintosh, and Chamizo’s (2010, Experiment 2) navigation protocol, we conducted two experiments, one with males and another with females, in order to tentatively evaluate the role of the dorsal hippocampus in the acquisition of two tasks: one based on landmark learning and the alternate one on local pool-geometry learning. Both when landmark learning and when geometry learning, Sham male rats learned significantly faster than Lesion male animals. This was not the case with female rats in geometry learning. These results suggest that the dorsal hippocampus could play an important role in males only.

Palatal Position of Patient Tracker for Magnetic Neuronavigation System: Technical Note

Recently, the neuronavigation system (NS) has become an essential intraoperative tool for many neurosurgical procedures, allowing for precise lesion localization. It is particularly important to avoid errors during the navigation process. Here we report a novel technique using palatal positioning of the patient tracker to ensure optimal accuracy during magnetic navigation in various neurosurgical procedures. This retrospective study included a total of 34 patients treated in our institution between June 2017 and January 2018. The patients were split into 2 groups who underwent surgery under general anesthesia: a microscopic transcranial group and an endoscopic endonasal group. Preoperative and postoperative navigation accuracy was assessed by 2 neurosurgeons. After our surgical planning navigation protocol was applied, both transcranial and endonasal procedures were successfully performed under navigation guidance in all but 1 patient. There were no intraoperative or postoperative complications related to the tracker mounted under the hard palate. In 33 cases a maximal tracking view and optimal navigation accuracy was achieved, for a success rate of 97%. The positioning of the patient tracker under the hard palate proved safe, accurate, and feasible in 97% of our patients. In our case series, it met the main goal of avoiding device displacement without a sense of invasiveness and postoperative patient discomfort.

Multiscale unfolding of real networks by geometric renormalization

Symmetries in physical theories denote invariance under some transformation, such as self-similarity under a change of scale. The renormalization group provides a powerful framework to study these symmetries, leading to a better understanding of the universal properties of phase transitions. However, the small-world property of complex networks complicates application of the renormalization group by introducing correlations between coexisting scales. Here, we provide a framework for the investigation of complex networks at different resolutions. The approach is based on geometric representations, which have been shown to sustain network navigability and to reveal the mechanisms that govern network structure and evolution. We define a geometric renormalization group for networks by embedding them into an underlying hidden metric space. We find that real scale-free networks show geometric scaling under this renormalization group transformation. We unfold the networks in a self-similar multilayer shell that distinguishes the coexisting scales and their interactions. This in turn offers a basis for exploring critical phenomena and universality in complex networks. It also affords us immediate practical applications, including high-fidelity smaller-scale replicas of large networks and a multiscale navigation protocol in hyperbolic space, which betters those on single layers.

Similar reliability and equivalent performance of female and male mice in the open field and water-maze place navigation task.

Although most nervous system diseases affect women and men differentially, most behavioral studies using mouse models do not include subjects of both sexes. Many researchers worry that data of female mice may be unreliable due to the estrous cycle. Here, we retrospectively evaluated sex effects on coefficient of variation (CV) in 5,311 mice which had performed the same place navigation protocol in the water‐maze and in 4,554 mice tested in the same open field arena. Confidence intervals for Cohen's d as measure of effect size were computed and tested for equivalence with 0.2 as equivalence margin. Despite the large sample size, only few behavioral parameters showed a significant sex effect on CV. Confidence intervals of effect size indicated that CV was either equivalent or showed a small sex difference at most, accounting for less than 2% of total group to group variation of CV. While female mice were potentially slightly more variable in water‐maze acquisition and in the open field, males tended to perform less reliably in the water‐maze probe trial. In addition to evaluating variability, we also directly compared mean performance of female and male mice and found them to be equivalent in both water‐maze place navigation and open field exploration. Our data confirm and extend other large scale studies in demonstrating that including female mice in experiments does not cause a relevant increase of data variability. Our results make a strong case for including mice of both sexes whenever open field or water‐maze are used in preclinical research.

Energy-Efficient Algorithm to Construct the Information Potential Field in WSNs

The information gradient-based routing and navigation protocols have been proved to be effective when collecting data from the distributed wireless sensor networks, because the data collector can achieve the global objective through local greedy decision based on the information gradient. An efficient method to establish this information gradient is to solve a discrete approximation to the harmonic function, which is called information potential field (IPF). However, the energy-efficient and quick convergence methods to construct the IPF should be fully investigated to trade off the energy efficiency and the quality of the IPF, especially in the large-scale networks with high dynamics. In this paper, two algorithms are proposed to efficiently construct the IPF, including <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">hierarchical skeleton-based construction algorithm</i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">value estimating substitution algorithm</i> . Both algorithms obey the typical hypotheses on WSN settings and the gossip-styled propagation principle. In addition, we propose the advanced approaches to construct the IPF to tackle the challenges of its practical applications, such as obstacles, task priorities, and sensor energy budget. Comprehensive simulation results show the feasibility of the proposed algorithms, which can reduce the number of iterations to reach a convergence status by 80% so as to conserve energy, and they perform well considering the requirements of real applications.

The use of intraoperative computed tomography navigation in pituitary surgery promises a better intraoperative orientation in special cases.

Objective:The safety of endoscopic skull base surgery can be enhanced by accurate navigation in preoperative computed tomography (CT) and magnetic resonance imaging (MRI). Here, we report our initial experience of real-time intraoperative CT-guided navigation surgery for pituitary tumors in childhood.Materials and Methods:We report the case of a 15-year-old girl with a huge growth hormone-secreting pituitary adenoma with supra- and perisellar extension. Furthermore, the skull base was infiltrated. In this case, we performed an endonasal transsphenoidal approach for debulking the adenoma and for chiasma decompression. We used an MRI neuronavigation (Medtronic Stealth Air System) which was registered via intraoperative CT scan (Siemens CT Somatom). Preexisting MRI studies (navigation protocol) were fused with the intraoperative CT scans to enable three-dimensional navigation based on MR and CT imaging data. Intraoperatively, we did a further CT scan for resection control.Results:The intraoperative accuracy of the neuronavigation was excellent. There was an adjustment of <1 mm. The navigation was very helpful for orientation on the destroyed skull base in the sphenoid sinus. After opening the sellar region and tumor debulking, we did a CT scan for resection control because the extent of resection was not credible evaluable in this huge infiltrating adenoma. Thereby, we were able to demonstrate a sufficient decompression of the chiasma and complete resection of the medial part of the adenoma in the intraoperative CT images.Conclusions:The use of intraoperative CT/MRI-guided neuronavigation for transsphenoidal surgery is a time-effective, safe, and technically beneficial technique for special cases.

Range‐only distributed navigation protocol for uniform coverage in wireless sensor networks

In this study, the authors propose a novel range-only distributed motion coordination to achieve square-grid blanket coverage for self-deployments of networked multi-robot systems. They specifically address the research question of maximising coverage and minimising local uniformity index (i.e. to achieve uniform coverage) for each sensor node while simultaneously maintaining the connectivity of the whole network in the absence of central coordinated controller. Under the umbrella of intelligent controls, the motion coordination scheme employed in this study is because of the nearest neighbour techniques which are employed for the purpose of clustering and autonomous coordination among sensor nodes in local area (vicinity), that is, to achieve distributed coverage. The author's research indicates that simple motion coordination schemes have led to intelligent ensemble behaviours at group levels. Compared to the existing algorithms, the superiorities of their decentralised protocol are because of its reliability and robustness against inevitable node failures, scalability and flexibility in the sense of the growth of the networks as well as its uniformity across most of steady-state positions of sensor nodes leading to better network management. They present extensive computer simulations to investigate the effectiveness of their proposed algorithm for self-deployment in challenging deployment regions.

A novel protocol of continuous navigation guidance for endoscopic third ventriculostomy.

Although considered a standard neurosurgical procedure, endoscopic third ventriculostomy (ETV) is associated with a relatively high complication rate that is predominantly related to malpositioning of the trajectory. To develop an advanced navigation protocol for ETV, assess its possible benefits over commonly used ETV trajectories, and apply this protocol during surgery. After development of our advanced protocol, the imaging data of 59 patients who underwent ETV without navigation guidance was transferred to our navigation software. An individualized endoscope trajectory was created according to our protocol in all cases. This trajectory was compared with 2 standard trajectories, especially with regard to the distance to relevant neuronal structures: a trajectory manually measured on preoperative radiological images, as performed in all 59 cases, and a trajectory resulting from a commonly used fixed coronal burr hole. Subsequently, we applied the protocol in 15 ETVs to assess the feasibility and procedural complications. Our individualized trajectory resulted in a significantly greater distance to the margins of the foramen of Monro, and the burr hole was located more posteriorly from the coronal suture in comparison with the standard trajectories. The advanced ETV technique was feasible in all 15 procedures, and no major complications occurred in any procedure. In 1 patient, a fornix contusion without clinical correlation was observed. Our data indicate that the proposed navigation protocol for ETV optimizes the distance of the endoscope to important neuronal structures. Continuous endoscope and puncture device guidance may further add to the safety of this procedure.