A trans-Canadian positive deviance seminar for paraesophageal hernia surgery: Reporting national postoperative outcomes and consensus recommendations.

BACKGROUND: The incidence of adverse events (AEs) and length of stay (LOS) varies significantly following paraesophageal hernia surgery. We performed a Canadian multicenter positive deviance (PD) seminar to review individual center and national level data and establish holistic perioperative practice recommendations. METHODS: A national virtual PD seminar was performed in October 2021. Recent best evidence focusing on AEs and LOS was presented. Subsequently, anonymized center-level AE and LOS data collected between 01/2017 and 01/2021 from a prospective, web-based database that tracks postoperative outcomes was presented. The top two performing centers with regards to these metrics were chosen and surgeons from these hospitals discussed elements of their treatment pathways that contributed to these outcomes. Consensus recommendations were then identified with participants independently rating their level of agreement. RESULTS: Twenty-eight surgeons form 8 centers took part in the seminar across 5 Canadian provinces. Of the 680 included patients included, Clavien-Dindo grade I and II/III/IV/V complications occurred in 121/39/12/2 patients (17.8%/5.7%/1.8%/0.3%). Respiratory complications were the most common (effusion 12/680, 1.7% and pneumonia 9/680, 1.3%). Esophageal and gastric perforation occurred in 7 and 4/680, (1.0% and 0.6% respectively). Median LOS varied significantly between institutions (1 day, range 1-3 vs. 7 days, 3-8, p < 0.001). A strong level of agreement was achieved for 10/12 of the consensus statements generated. CONCLUSION: PD seminars provide a supportive forum for centers to review best evidence and experience and generate recommendations based on expert opinion. Further research is ongoing to determine if this approach effectively accomplishes this objective.

Prostate implant reconstruction from C-arm images with motion-compensated tomosynthesis.

PURPOSE: Accurate localization of prostate implants from several C-arm images is necessary for ultrasound-fluoroscopy fusion and intraoperative dosimetry. The authors propose a computational motion compensation method for tomosynthesis-based reconstruction that enables 3D localization of prostate implants from C-arm images despite C-arm oscillation and sagging. METHODS: Five C-arm images are captured by rotating the C-arm around its primary axis, while measuring its rotation angle using a protractor or the C-arm joint encoder. The C-arm images are processed to obtain binary seed-only images from which a volume of interest is reconstructed. The motion compensation algorithm, iteratively, compensates for 2D translational motion of the C-arm by maximizing the number of voxels that project on a seed projection in all of the images. This obviates the need for C-arm full pose tracking traditionally implemented using radio-opaque fiducials or external trackers. The proposed reconstruction method is tested in simulations, in a phantom study and on ten patient data sets. RESULTS: In a phantom implanted with 136 dummy seeds, the seed detection rate was 100% with a localization error of 0.86 ± 0.44 mm (Mean ± STD) compared to CT. For patient data sets, a detection rate of 99.5% was achieved in approximately 1 min per patient. The reconstruction results for patient data sets were compared against an available matching-based reconstruction method and showed relative localization difference of 0.5 ± 0.4 mm. CONCLUSIONS: The motion compensation method can successfully compensate for large C-arm motion without using radio-opaque fiducial or external trackers. Considering the efficacy of the algorithm, its successful reconstruction rate and low computational burden, the algorithm is feasible for clinical use.

Computing intraoperative dosimetry for prostate brachytherapy using TRUS and fluoroscopy.

RATIONALE AND OBJECTIVES: There is a need to provide real-time dosimetric feedback during prostate brachytherapy based on the location of the implanted seeds. The objective of our approach is to develop a system to accurately locate seeds with minimal impact on the current protocol for prostate brachytherapy and without additional imaging equipment. MATERIALS AND METHODS: A new approach for intraoperatively computing dosimetry for prostate brachytherapy is presented. The approach uses transrectal ultrasound (TRUS) and fluoroscopic images. A fluoroscopic image of the TRUS probe is required to register the fluoroscopic and ultrasound images. The C-arm is not moved during the procedure and all images are acquired from the same C-arm angles. A needle path is interpolated for each needle based on the location of the needle tip in TRUS images and the known entry point of the needle. Throughout the procedure, fluoroscopic images are acquired to determine the coronal plane coordinates of the seeds and the remaining coordinate of each seed is computed from the needle path. For accurate results, intraoperative seed motion tracking is advised and a method to achieve such tracking is also presented. RESULTS: Experimentally, the TRUS and fluoroscopic images are registered with a mean and maximum error of 1.3 mm and 5.8 mm, respectively. In a phantom, 12 seeds are located using our approach and compared with the known locations, with a mean error in the x, y, and z direction of 0.96 mm, 0.33, and 0.68 mm, respectively, and a corresponding maximum error of 1.85 mm, 0.56 mm, and 1.63 mm. Experimental results show motion tracking in the y-direction with submillimeter accuracy. The feasibility of our approach is tested on five cases of clinical data using a semiautomated version of our system and the resulting dosimetry is compared with that found using postoperative computed tomography images. The D90 and V100 metrics computed using our approach and the computed tomography images differ by a maximum of 16.6% and 1.7%, respectively. CONCLUSIONS: TRUS can be combined with single pose fluoroscopic images to compute delivered dose intraoperatively for prostate brachytherapy. Phantom results demonstrate the accuracy of the method and preliminary clinical results show its potential.