BACKGROUND: A coordinated care system helps provide timely access to treatment for suspected acute stroke. In Northwestern Ontario (NWO), Canada, communities are widespread with several hospitals offering various diagnostic equipment and services. Thus, resources are limited, and health care providers must often transfer patients with stroke to different hospital locations to ensure the most appropriate care access within recommended time frames. However, health care providers frequently situated temporarily (locum) in NWO or providing care remotely from other areas of Ontario may lack sufficient information and experience in the region to access care for a patient with a time-sensitive condition. Suboptimal decision-making may lead to multiple transfers before definitive stroke care is obtained, resulting in poor outcomes and additional health care system costs.
OBJECTIVE: We aimed to develop a tool to inform and assist NWO health care providers in determining the best transfer options for patients with stroke to provide the most efficient care access. We aimed to develop an app using a comprehensive geomapping navigation and estimation system based on machine learning algorithms. This app uses key stroke-related timelines including the last time the patient was known to be well, patient location, treatment options, and imaging availability at different health care facilities.
METHODS: Using historical data (2008-2020), an accurate prediction model using machine learning methods was developed and incorporated into a mobile app. These data contained parameters regarding air (Ornge) and land medical transport (3 services), which were preprocessed and cleaned. For cases in which Ornge air services and land ambulance medical transport were both involved in a patient transport process, data were merged and time intervals of the transport journey were determined. The data were distributed for training (35%), testing (35%), and validation (30%) of the prediction model.
RESULTS: In total, 70,623 records were collected in the data set from Ornge and land medical transport services to develop a prediction model. Various learning models were analyzed; all learning models perform better than the simple average of all points in predicting output variables. The decision tree model provided more accurate results than the other models. The decision tree model performed remarkably well, with the values from testing, validation, and the model within a close range. This model was used to develop the \"NWO Navigate Stroke\" system. The system provides accurate results and demonstrates that a mobile app can be a significant tool for health care providers navigating stroke care in NWO, potentially impacting patient care and outcomes.
CONCLUSIONS: The NWO Navigate Stroke system uses a data-driven, reliable, accurate prediction model while considering all variations and is simultaneously linked to all required acute stroke management pathways and tools. It was tested using historical data, and the next step will to involve usability testing with end users.

Locomotor and balance disorders are major limitations for subjects with hemiparesis. The Timed Up and Go (TUG) test is a complex navigational task involving oriented walking and obstacle circumvention. We hypothesized that subjects with hemiparesis adopt a cautious gait during complex locomotor tasks. The primary aim was to compare spatio-temporal gait parameters, indicators of cautious gait, between the locomotor subtasks of the TUG (Go, Turn, Return) and a Straight-line walk in people with hemiparesis. Our secondary aim was to analyze the relationships between TUG performance and balance measures, compare spatio-temporal gait parameters between fallers and non-fallers, and identify the biomechanical determinants of TUG performance. Biomechanical parameters during the TUG and Straight-line walk were analyzed using a motion capture system. A repeated measures ANOVA and two stepwise ascending multiple regressions (with performance variables and biomechanical variables) were conducted. Gait speed, step length, and % single support phase (SSP) of the 29 participants were reduced during Turn compared to Go and Return and the Straight-line walk, and step width and % double support phase were increased. TUG performance was related to several balance measures. Turn performance (R2 = 63%) and Turn trajectory deviation followed by % SSP on the paretic side and the vertical center of mass velocity during Go (R2 = 71%) determined TUG performance time. People with hemiparesis adopt a cautious gait during complex navigation at the expense of performance.

UNASSIGNED: Mild ligament imbalance is often encountered in the mediolateral plane during complex primary total knee arthroplasty. A constrained (CP) polyethylene insert compatible with the primary femur is useful to manage these cases without the need to fall back on revision implants. The aim of the study was to define the correct indications of the use of a CP insert based on objective data from computer assisted surgery and to compare the early results of a CP insert with a standard posterior stabilized (PS) insert through one-to-one propensity score matching.
UNASSIGNED: This is a retrospective case study from a prospectively collected database. One-to-one matching without replacement was used with a caliper width of 0.2 to match the scores between CP (N = 64) and PS groups (N = 1624), resulting in equal covariate matching of PS (N = 64) and CP (N = 64) cohorts. Patients were assessed radiographically and functionally at a minimum follow-up of 3 years.
UNASSIGNED: Average coronal and sagittal plane deformities were similar in both the group CP (varus 13.1 ± 5.2 valgus 13 ± 7.9) and the group PS (varus 13.4 ± 4.6 valgus 10.9 ± 8.6). The average residual medial lateral gap difference was significantly higher in group CP (3.8 ± 1.8) in comparison to group PS (1.3 ± 1) (P < .05). A CP insert was chosen where mild ligament imbalance of 3-5 mm persisted after medial soft tissue releases in a varus knee and in cases with residual medial collateral ligament laxity in valgus knees.
UNASSIGNED: Constrained insert used with the primary femoral component is a valuable option to handle mild ligamentous instability in complex primary total knee arthroplasty after mechanical alignment is achieved with computer navigation.
UNASSIGNED: III.

OBJECTIVE: The insertion of ilio-sacral (IS) screws for distal anchoring in the instrumentation of pediatric neuromuscular scoliosis (NS) presents a significant challenge, often leading to elevated rates of complications. Utilizing computed tomography (CT) navigation and preoperative planning technology is proposed as a potential solution to mitigate these challenges. This study aims to assess the precision of IS screw placement through CT-graphic measurements, both with and without preoperative planning, followed by navigated IS screw insertion, in pediatric neuromuscular scoliosis.
METHODS: Thirty-two treated patients were grouped based on surgical procedure: planned (P): 19 patients (n = 38 screws) and non-planned (NP): 13 patients (n = 26 screws). All screw placements (P and NP) took place under CT navigation. IS screw trajectories of P-group were drawn preoperatively on CT images with the cranial trajectory planning program and fused with the intraoperative CT images. There are several important anatomical structures that should be avoided when placing the IS screw (L5 root, spinal canal, L5S1 facet, SI joint, neurovascular structures anteriorly to the sacrum, S1 root in the S1 foramen and the intestines). Each trajectory was evaluated based on seven radiographical parameters whom we have enlisted partially based on the essentials of a good trajectory described by Miladi et al. (1: Ilium; 2: SI joint; 3: Promontorium; 4: Sacral plate; 5: Anterior sacral cortex; 6: S1 foramen; 7: Spinal canal). An independent sample T test was executed to compare both groups.
RESULTS: The trajectories in the P group showed a significantly (P < 0.05) higher overall similarity and optimality (12.1 ± 2.1 vs 9.1 ± 2.2 points) compared to the non-planned trajectory.
CONCLUSIONS: Preoperative planning and navigated placement of IS screws on fusion images with intraoperative CT, results in a better trajectory of the ilio-sacral screws.

Background and objectives Mixed reality (MR) is one of the image processing technologies that allows the user to manipulate three-dimensional (3D) virtual images (hologram). The aim of this study was to evaluate the accuracy of MR-based pedicle screw (PS) placement using 3D spine models. Materials and methods Using the preoperative CT data of a patient with adolescent idiopathic scoliosis (AIS) who had undergone posterior spinal fusion in our hospital, a 3D-printed spine model was created. On the other hand, a 3D hologram of the same patient was automatically created using the preoperative CT data uploaded to the Holoeyes MD service website (Holoeyes Inc., Tokyo, Japan). Using a Magic Leap One® headset (Magic Leap Inc., Plantation, FL), the 3D hologram with lines of predetermined PS trajectories was superimposed onto the 3D-printed spine model and PS were inserted bilaterally along with the trajectory lines from T5 to L3. As a control, we used a readymade 3D spine model of AIS and inserted PS bilaterally with a freehand technique from T4 to L3. The rate of pedicle violation was compared between the MR-based and freehand techniques. Results A total of 22 and 24 PS were placed into the 3D-printed spine model of our patient and the readymade 3D spine model, respectively. The rate of pedicle violation was 4.5% (1/22 screws) in the MR-based technique and 29.2% (7/24 screws) in the freehand technique (P = 0.049). Conclusions We demonstrated a significantly lower rate of PS misplacement in the MR-based technique than in the freehand technique. Therefore, an MR-assisted system is a promising tool for PS placement in terms of feasibility, safety, and accuracy, warranting further studies including cadaveric and clinical studies.

BACKGROUND: Correct acetabular component placement plays a critical role in reducing early revisions after dislocations in total hip arthroplasty (THA). Although the transverse acetabular ligament (TAL) guides anteversion, inclination can only be accurately guided by navigation. In order to overcome the initial disadvantages with navigation, an imageless, easy-to-use inertial navigation system has been recently introduced. This study aims to analyze the accuracy of inclination with this navigation system compared to the standard manual technique.
METHODS: Two cohorts, manual technique (MT) and navigation (NAV) cohorts, consisted of 83 and 95 patients, respectively, after exclusion criteria were applied. Inclination target was 38° and anteversion was guided by TAL. Demographic data were collected, and anteroposterior (AP) pelvic and cross-table lateral radiographs were obtained 6 weeks post-operatively. Inclination and anteversion were determined on the AP pelvic and cross-table lateral radiograph, respectively.
RESULTS: A mean inclination of 41.8° (±6.8°) and 38.9° (±4.4°) was found in the MT and NAV cohorts, respectively. There was no statistical difference in gender, age, and BMI. If the inclination was set within 10° of the target (i.e., 38°), 88% of the MT cohort and 97% of the NAV cohort were within the target zone. Accuracy decreased to 53% and 83%, respectively, if the target zone range was narrowed down to ± 5°.
CONCLUSIONS: Combining inertial imageless navigation for inclination and TAL as a landmark for anteversion is significantly more accurate compared to the manual technique, without having the limitations and disadvantages of current standard navigational techniques.

BACKGROUND: Accurate pedicle screw placement is a challenge with reported misplacement rates of 10% and higher. A handheld navigation device (HND) may provide accuracy equal to CT-based navigation (CT-Nav) but without the cost and complexity.
OBJECTIVE: To study the accuracy of a handheld navigation device for pedicle screw placement.
METHODS: This prospective cross-sectional study with consistently applied reference standard enrolled 20 patients undergoing 92 pedicle screw placements.
METHODS: Patients who underwent pedicle screw placement between May 2022 and September 2022.
METHODS: Pedicle screw placement accuracy per Gertzbein-Robbins.
METHODS: Once the screw pilot hole was established, the proposed trajectory of the HND was compared with that proposed by CT-Nav. Postoperatively, screw accuracy was graded according to Gertzbein-Robbins by a blinded radiologist based on CT scans. Accuracy was compared between the two systems and published control for fluoroscopy assisted and CT-Nav placement using Bayesian posterior distribution.
RESULTS: The trajectory proposed by the HND and CT-Nav were in agreement in 98.9% (95% Exact CI; 94.09%-99.97%). The HND accuracy was 98.9% with 91 screws rated \"A\" and 1 rated \"C\". Non-inferiority to fluoroscopic placement was achieved because the one-sided normal-approximation 95% CI Lower Bound (LB) of 95.3% is greater than the Performance Goal (PG) of 83.4%. Post-hoc analysis demonstrated that the probability of superiority of the HND relative to the historical accuracy rate of 91.5% for fluoroscopy assisted procedures is >0.999 and that the HND\'s accuracy rate is within 4.5% of CT-Nav of 95.5% is >0.999. No adverse events or intra-operative complications associated with HND were observed. There was 1 (1.1%) intra-operative repositioning and no re-operations for any reason.
CONCLUSIONS: The accuracy rate of the HND was 98.9%, and the proposed trajectory matched with CT-Nav in 98.9% of the time. This is superior to the historical published accuracy rate for fluoroscopy-assisted procedures and equivalent to the historical published accuracy rate for CT-Nav.
BACKGROUND: Dutch trial register NL74268.058.20.

UNASSIGNED: The posterior orbit is a confined space, harbouring neurovascular structures, frequently distorted by tumours. Image-guided navigation (IGN) has the potential to allow accurate localisation of these lesions and structures, reducing collateral damage whilst achieving surgical objectives.
UNASSIGNED: We assessed the feasibility, effectiveness and safety of using an electromagnetic IGN for posterior orbital tumour surgery via a comparative cohort study. Outcomes from cases performed with IGN were compared with a retrospective cohort of similar cases performed without IGN, presenting a descriptive and statistical comparative analysis.
UNASSIGNED: Both groups were similar in mean age, gender and tumour characteristics. IGN set-up and registration were consistently achieved without significant workflow disruption. In the IGN group, fewer lateral orbitotomies (6.7% IGN, 46% non-IGN), and more transcutaneous lid and transconjunctival incisions (93% IGN, 53% non-IGN) were performed (p = .009). The surgical objective was achieved in 100% of IGN cases, with no need for revision surgery (vs 23% revision surgery in non-IGN, p = .005). There was no statistically significant difference in surgical complications.
UNASSIGNED: The use of IGN was feasible and integrated into the orbital surgery workflow to achieve surgical objectives more consistently and allowed the use of minimal access approaches. Future multicentre comparative studies are needed to explore the potential of this technology further.

Objectives: Augmented reality (AR) navigation systems are emerging to simplify and enhance the precision of medical procedures. Lumbosacral transforaminal epidural injection is a commonly performed procedure for the treatment and diagnosis of radiculopathy. Accurate needle placement while avoiding critical structures remains a challenge. For this purpose, we conducted a randomized controlled trial for our augmented reality navigation system. Methods: This randomized controlled study involved 28 patients, split between a traditional C-arm guided group (control) and an AR navigation guided group (AR-NAVI), to compare procedure efficiency and radiation exposure. The AR-NAVI group used a real-time tracking system displaying spinal structure and needle position on an AR head-mounted display. The procedural time and C-arm usage (radiation exposure) were measured. Results: All patients underwent successful procedures without complications. The AR-NAVI group demonstrated significantly reduced times and C-arm usage for needle entry to the target point (58.57 ± 33.31 vs. 124.91 ± 41.14, p < 0.001 and 3.79 ± 1.97 vs. 8.86 ± 3.94, p < 0.001). Conclusions: The use of the AR navigation system significantly improved procedure efficiency and safety by reducing time and radiation exposure, suggesting a promising direction for future enhancements and validation.

Hepatolithiasis is a complex condition that poses challenges and difficulties in surgical treatment. Three-dimensional visualization technology combined with fluorescence imaging (3DVT-FI) enables accurate preoperative assessment and real-time intraoperative navigation. However, the perioperative outcomes of 3DVT-FI in hepatolithiasis have not been reported. We aim to evaluate the efficacy of 3DVT-FI in the treatment of hepatolithiasis.
A retrospective analysis was performed on 128 patients who underwent hepatectomy for hepatolithiasis at the Department of Hepatobiliary Surgery, Zhujiang Hospital, between January 2017 and December 2022. Among them, 50 patients underwent hepatectomy using 3DVT-FI (3DVT-FI group), while 78 patients underwent conventional hepatectomy without 3DVT-FI (CH group). The operative data, postoperative liver function indices, complication rates and stone residue were compared between the two groups.
There were no significant differences in preoperative baseline data between the two groups (p > 0.05). Compared with the CH group, the 3DVT-FI group exhibited lower intraoperative blood loss (140.00 ± 112.12 vs. 225.99 ± 186.50 mL, p = 0.001), and a lower intraoperative transfusion rate (8.0% vs. 23.1%, p = 0.027). The overall incidence of postoperative complications did not differ significantly (22.0% vs. 35.9%, p = 0.096). The 3DVT-FI group was associated with a lower immediate residual stone rate (16.0% vs. 34.6%, p = 0.021). There were no perioperative deaths in the 3DVT-FI group, while one perioperative death occurred in the CH group.
The 3DVT-FI may offer significant benefits in terms of surgical safety, reduced intraoperative bleeding and decreased stone residue during hepatectomy for hepatolithiasis.