Radiation Exposure from GEP NET Surveillance.

BACKGROUND: Neuroendocrine tumors (NET) are neoplasms that secrete peptides and neuroamines. For gastroenteropancreatic (GEP) NET, surgical resection represents the only curative option. Ten-year imaging surveillance programs are recommended due to long time-to-recurrence following resection. We performed retrospective chart review evaluating radiation exposure and practice patterns from surveillance of completely resected GEP NET. METHODS: We performed a retrospective cohort study of cases with well-differentiated GEP NET from January 2005 to July 2020. Location of primary, modality of imaging, and duration of follow-up were collected. Dosimetry data was collected to calculate effective dose. RESULTS: 62 cases were included with 422 surveillance scans performed. Cross-sectional imaging was used in 82% and functional imaging was used in 18% of scans. Mean number of scans per year was 1.25 (0.42-3). Mean total effective dose was 56.05 mSv (SD 45.56; 0 to 198 mSv) while mean total effective dose per year was 10.62 mSv (SD 9.35; 0 to 45 mSv). Over the recommended ten years of surveillance the estimated total effective dose was 106 mSv. CONCLUSIONS: Surveillance of completely resected GEP NET results in cumulative radiation doses in the range associated with secondary malignancy development. Strategies to minimize radiation exposure in surveillance should be considered in future guideline development.

Perception versus reality: A case-matched study assessing the intraoperative hemodynamics of minimally invasive retroperitoneal versus transperitoneal approach to pheochromocytomas.

BACKGROUND: Pheochromocytomas produce excess catecholamines that can result in intraoperative hemodynamic instability. Centers have reported variations in intraoperative hemodynamics with the retroperitoneoscopic versus the laparoscopic transperitoneal approach to adrenalectomies. When the retroperitoneoscopic approach was initiated for pheochromocytomas at our institution, the perception was of improved intraoperative hemodynamics, hypothesizing that increased retroperitoneoscopic insufflation pressures caused decreased venous return and less fluctuation in circulating catecholamines. The purpose of this study was to examine if a difference in intraoperative hemodynamics exists between a size-matched cohort of laparoscopic transperitoneal and retroperitoneoscopic pheochromocytoma patients. METHODS: Unilateral adrenalectomies for pheochromocytoma performed via laparoscopic transperitoneal or retroperitoneoscopic approaches from 2015 to 2021 were identified from a surgical database. As larger tumors often underwent a laparoscopic transperitoneal approach, cases were matched 1:1 by tumor size. All patients received phenoxybenzamine. Groups were compared by patient characteristics, preoperative blockade, intraoperative hemodynamics and management, and early postoperative outcomes. RESULTS: There were 13 laparoscopic transperitoneal adrenalectomy cases matched to 13 retroperitoneoscopic cases according to tumor size. Both groups (laparoscopic transperitoneal and retroperitoneoscopic) were similar for age (53 years), body mass index (28.5 vs 29.7), sex (69% female), and side (8 vs 7 right). There was no difference in preoperative 24-hour urine metanephrines/normetanephrines (9.9/8.0 vs 2.4/5.7 µmol/day). The phenoxybenzamine dose was similar in both groups (112 vs 114 mg/24 hours), as were baseline heart rate, blood pressure, and mean arterial pressure. There was no difference in any intraoperative hemodynamic parameters or vasoactive interventions. Operative time, length of stay, and 30-day emergency visits were similar between groups. CONCLUSION: This matched cohort study did not find a difference in intraoperative hemodynamics between laparoscopic transperitoneal and retroperitoneoscopic adrenalectomy approaches for pheochromocytoma in appropriately selected and blocked patients.

Etiology and Pathophysiology of Hypoparathyroidism: A Narrative Review.

The approach utilized a systematic review of the medical literature executed with specifically designed criteria that focused on the etiologies and pathogenesis of hypoparathyroidism. Enhanced attention by endocrine surgeons to new knowledge about parathyroid gland viability are reviewed along with the role of intraoperative parathyroid hormone (ioPTH) monitoring during and after neck surgery. Nonsurgical etiologies account for a significant proportion of cases of hypoparathyroidism (~25%), and among them, genetic etiologies are key. Given the pervasive nature of PTH deficiency across multiple organ systems, a detailed review of the skeletal, renal, neuromuscular, and ocular complications is provided. The burden of illness on affected patients and their caregivers contributes to reduced quality of life and social costs for this chronic endocrinopathy. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

The adoption of the endoscopic retroperitoneal approach to the adrenal gland - Conversion factors and learning points.

INTRODUCTION: Minimally invasive adrenalectomy includes laparoscopic transperitoneal (LA) and retroperitoneoscopic (RP) approaches. This study reviewed the local adrenalectomy practice to identify characteristics and outcomes between patients undergoing adrenalectomy via LA, RP, and RP requiring conversion (RPC). METHODS: Adrenalectomies documented in a prospective surgical database were reviewed. Demographics, diagnosis, surgical approach/conversion, body mass index (BMI), radiographic body measurements (RBM), tumor size, operative time (OT), length of stay (LOS), and 30-day post-operative emergency (ED) visits were collected. RESULTS: 203 adrenalectomies were reviewed from 2015 to 2020. The RP group had the shortest OT (124 ± 54 min, p = 0.281 vs LA, p < 0.001 vs RPC) and LOS (1.6 ± 1.0 days, p < 0.001 vs LA and RPC). There was an 18% conversion rate from RP to LA, and in one case to laparotomy. The RPC group had greater BMI, OT, LOS, and ED visits than LA and RP. The RPC group had less favorable RBM (p < 0.001). On multivariate analysis, RBM impacted OT, LOS, and ED visits (p < 0.05). DISCUSSION: The RP approach had shorter OT and LOS. BMI and RBM may increase risk of conversion, OT, LOS, and ED visits. Preoperative RBM may aid in appropriate patient selection for a RP approach.

Considerations in the Management of Malignant Bowel Obstruction.

Malignant bowel obstruction is a challenging clinical problem encountered in patients with advanced abdominal and pelvic malignancies. Although medical therapies form the foundation of management, some patients may be suitable candidates for surgical and procedural interventions. The literature is composed primarily of retrospective single-institution experiences and the results of prospective trials are pending. Given the high symptom burden and limited life expectancy of these patients, management may be best informed by multidisciplinary teams with relevant expertise.

The value of dynamic surgeon-directed imaging in the preoperative planning of patients with primary hyperparathyroidism.

BACKGROUND: Preoperative localization plays an important role in primary hyperparathyroidism. Sestamibi scans read by the radiologist as nonlocalizing were localizing when independently interpreted by the surgeon. The ability to perform dynamic surgeon-directed imaging, a of combination scans interpreted by the surgeon and surgeon-performed ultrasound done in tandem, appeared to improve preoperative localization. The objective was to evaluate scans read by the radiologist compared with dynamic surgeon-directed imaging. METHODS: A retrospective chart review was performed. Demographics, biochemistry, radiologist read scans, dynamic surgeon-directed imaging, operation, pathology, and follow-up results were collected. Localization rate, sensitivity, positive predictive value, and accuracy were calculated. RESULTS: In the study, 474 charts met inclusion criteria. Only 63% of scans read by the radiologist were localizing, compared with 96% of dynamic surgeon-directed imaging. Overall dynamic surgeon-directed imaging was superior to scans read by the radiologist with 95% versus 60% sensitivity, 85% versus 85% positive predictive value, and 82% versus 54% accuracy. Dynamic surgeon-directed imaging remained superior when analyzing only those with single gland disease (n = 391). In addition, 85% of the 174 nonlocalized radiologist scans were correctly localized by dynamic surgeon-directed imaging. CONCLUSION: The ability to perform an interpretation of both surgeon-performed ultrasound and scan interpreted by the surgeon in tandem improves the preoperative localization rate when compared with static reading of radiologist scans. This underscores the importance of having all primary hyperparathyroidism patients assessed by an experienced parathyroid surgical team, especially when the scans read by the radiologist is nonlocalizing.

Real-time electromagnetic navigation for breast-conserving surgery using NaviKnife technology: A matched case-control study.

Breast-conserving surgery (BCS) is a mainstay in breast cancer treatment. For nonpalpable breast cancers, current strategies have limited accuracy, contributing to high positive margin rates. We developed NaviKnife, a surgical navigation system based on real-time electromagnetic (EM) tracking. The goal of this study was to confirm the feasibility of intraoperative EM navigation in patients with nonpalpable breast cancer and to assess the potential value of surgical navigation. We recruited 40 patients with ultrasound visible, single, nonpalpable lesions, undergoing BCS. Feasibility was assessed by equipment functionality and sterility, acceptable duration of the operation, and surgeon feedback. Secondary outcomes included specimen volume, positive margin rate, and reoperation outcomes. Study patients were compared to a control group by a matched case-control analysis. There was no equipment failure or breach of sterility. The median operative time was 66 (44-119) minutes with NaviKnife vs 65 (34-158) minutes for the control (P = .64). NaviKnife contouring time was 3.2 (1.6-9) minutes. Surgeons rated navigation as easy to setup, easy to use, and useful in guiding nonpalpable tumor excision. The mean specimen volume was 95.4 ± 73.5 cm3 with NaviKnife and 140.7 ± 100.3 cm3 for the control (P = .01). The positive margin rate was 22.5% with NaviKnife and 28.7% for the control (P = .52). The re-excision specimen contained residual disease in 14.3% for NaviKnife and 50% for the control (P = .28). Our results demonstrate that real-time EM navigation is feasible in the operating room for BCS. Excisions performed with navigation result in the removal of less breast tissue without compromising postive margin rates.

Surgery Tutor for Computational Assessment of Technical Proficiency in Soft-Tissue Tumor Resection in a Simulated Setting.

BACKGROUND: In competency-based medical education, progression between milestones requires reliable and valid methods of assessment. Surgery Tutor is an open-source motion tracking platform developed to objectively assess technical proficiency during open soft-tissue tumor resections in a simulated setting. The objective of our study was to provide evidence in support of construct validity of the scores obtained by Surgery Tutor. We hypothesized that Surgery Tutor would discriminate between novice, intermediate, and experienced operators. METHODS: Thirty participants were assigned to novice, intermediate, or experienced groups, based on the number of prior soft-tissue resections performed. Each participant resected 2 palpable and 2 nonpalpable lesions from a soft-tissue phantom. Surgery Tutor was used to track hand and instrument motions, number of tumor breaches, and time to perform each resection. Mass of excised specimens and margin status were also recorded. RESULTS: Surgery Tutor scores demonstrated "moderate" to "good" internal structure (test-retest reliability) for novice, intermediate, and experienced groups (interclass correlation coefficient = 0.596, 0.569, 0.737; p < 0.001). Evidence in support of construct validity (consequences) was demonstrated by comparing scores of novice, intermediate, and experienced participantsfor number of hand and instrument motions (690 ± 190, 597 ± 169, 469 ± 110; p < 0.001), number of tumor breaches (29 ± 34, 16 ± 11, 9 ± 6; p < 0.001), time per resection (677 ± 331 seconds, 561 ± 210 seconds, 449 ± 148 seconds; p < 0.001), mass of completely excised specimens (22 ± 7g, 21 ± 11g, 17 ± 6 g; p = 0.035), and rate of positive margin (68%, 50%, 28%; p < 0.001). There was "strong" and "moderate" relationships between motion scores and Objective Structured Assessment of Technical Skill scores, and time per resection and Objective Structured Assessment of Technical Skill scores respectively (r = -0.60, p < 0.001; r = -0.54, p < 0.001). CONCLUSION: Surgery Tutor scores demonstrate evidenceof construct validity with regards to good internal structure, consequences, and relationship to other variables in the assessment of technical proficiency duringopen soft-tissue tumor resections in a simulated setting. Utilization of Surgery Tutor can provide formative feedback and objective assessment of surgical proficiency in a simulated setting.

Utility of 3D Reconstruction of 2D Liver Computed Tomography/Magnetic Resonance Images as a Surgical Planning Tool for Residents in Liver Resection Surgery.

OBJECTIVE: A fundamental aspect of surgical planning in liver resections is the identification of key vessel tributaries to preserve healthy liver tissue while fully resecting the tumor(s). Current surgical planning relies primarily on the surgeon's ability to mentally reconstruct 2D computed tomography/magnetic resonance (CT/MR) images into 3D and plan resection margins. This creates significant cognitive load, especially for trainees, as it relies on image interpretation, anatomical and surgical knowledge, experience, and spatial sense. The purpose of this study is to determine if 3D reconstruction of preoperative CT/MR images will assist resident-level trainees in making appropriate operative plans for liver resection surgery. DESIGN: Ten preoperative patient CT/MR images were selected. Images were case-matched, 5 to 2D planning and 5 to 3D planning. Images from the 3D group were segmented to create interactive digital models that the resident can manipulate to view the tumor(s) in relation to landmark hepatic structures. Residents were asked to evaluate the images and devise a surgical resection plan for each image. The resident alternated between 2D and 3D planning, in a randomly generated order. The primary outcome was the accuracy of resident's plan compared to expert opinion. Time to devise each surgical plan was the secondary outcome. Residents completed a prestudy and poststudy questionnaire regarding their experience with liver surgery and the 3D planning software. SETTING AND PARTICIPANTS: Senior level surgical residents from the Queen's University General Surgery residency program were recruited to participate. RESULTS: A total of 14 residents participated in the study. The median correct response rate was 2 of 5 (40%; range: 0-4) for the 2D group, and 3 of 5 (60%; range: 1-5) for the 3D group (p < 0.01). The average time to complete each plan was 156 ± 107 seconds for the 2D group, and 84 ± 73 seconds for the 3D group (p < 0.01). A total 13 of 14 residents found the 3D model easier to use than the 2D. Most residents noticed a difference between the 2 modalities and found that the 3D model improved their confidence with the surgical plan proposed. CONCLUSIONS: The results of this study show that 3D reconstruction for liver surgery planning increases accuracy of resident surgical planning and decreases amount of time required. 3D reconstruction would be a useful model for improving trainee understanding of liver anatomy and surgical resection, and would serve as an adjunct to current 2D planning methods. This has the potential to be developed into a module for teaching liver surgery in a competency-based medical curriculum.

Navigated Breast Tumor Excision Using Electromagnetically Tracked Ultrasound and Surgical Instruments.

OBJECTIVE: Lumpectomy, breast conserving tumor excision, is the standard surgical treatment in early stage breast cancer. A common problem with lumpectomy is that the tumor may not be completely excised, and additional surgery becomes necessary. We investigated if a surgical navigation system using intraoperative ultrasound improves the outcomes of lumpectomy and if such a system can be implemented in the clinical environment. METHODS: Position sensors were applied on the tumor localization needle, the ultrasound probe, and the cautery, and 3-D navigation views were generated using real-time tracking information. The system was tested against standard wire-localization procedures on phantom breast models by eight surgical residents. Clinical safety and feasibility was tested in six palpable tumor patients undergoing lumpectomy by two experienced surgical oncologists. RESULTS: Navigation resulted in significantly less tissue excised compared to control procedures (10.3 ± 4.4 versus 18.6 ± 8.7 g, p = 0.01) and lower number of tumor-positive margins (1/8 versus 4/8) in the phantom experiments. Excision-tumor distance was also more consistently outside the tumor margins with navigation in phantoms. The navigation system has been successfully integrated in an operating room, and user experience was rated positively by surgical oncologists. CONCLUSION: Electromagnetic navigation may improve the outcomes of lumpectomy by making the tumor excision more accurate. SIGNIFICANCE: Breast cancer is the most common cancer in women, and lumpectomy is its first choice treatment. Therefore, the improvement of lumpectomy outcomes has a significant impact on a large patient population.

Examination of Learning Trajectories for Simulated Lumbar Puncture Training Using Hand Motion Analysis.

OBJECTIVES: A prospective cohort study was conducted using hand motion analysis (HMA) to assess the acquisition and retention of technical proficiency among first-year medical students learning the lumbar puncture (LP) skill in a simulated setting. METHODS: Twenty-five subjects attended three or four simulation sessions at 6-week intervals. The initial session consisted of an introduction to the procedure and a baseline HMA assessment. This was followed by a session involving deliberate practice and evaluation using HMA. Subject HMA metrics were followed over time and compared to performance benchmarks to determine the volume of practice required to achieve and maintain technical proficiency in the simulated setting. Performance benchmarks were derived from the assessment of experts using HMA. RESULTS: Subject baseline metrics were significantly different from expert (p < 0.01). At the outset of session 2, none of the subjects achieved the performance benchmarks. At the outset of sessions 3 and 4, 40 and 60% of subjects, respectively, demonstrated retention of technical proficiency. However, there was evidence of significant skill erosion between sessions (p < 0.01). The mean number of practice attempts required to achieve technical proficiency declined between sessions. Regression analysis indicated that there was a significant training effect for all students (overall negative slopes) over time. When examining the group as a whole, the speed at which students reached the expert benchmark was not significantly associated with number of practices in the first three sessions, although for some individuals these factors did appear associated. A total of 76% of subjects retained technical proficiency by session 4 and required a mean of 14 practices (range = 5 to 19). CONCLUSIONS: These results show that the majority of students require three to four sessions of deliberate practice to achieve a sustainable level of proficiency in the LP procedure. There is considerable variation in learning progression and retention of technical proficiency. These results have important implications for the design and resource requirements of a competency-based medical education program targeting LP training.

Electromagnetic tracking performance analysis and optimization.

PURPOSE: The purpose of this study is to evaluate the uncertainties of an electromagnetic (EM) tracking system and to improve both the trueness and the precision of the EM tracker. METHODS: For evaluating errors, we introduce an optical (OP) tracking system and consider its measurement as "ground truth". In the experiment, static data sets and dynamic profiles are collected in both relatively less-metallic environments. Static data sets are for error modeling, and dynamic ones are for testing. To improve the trueness and precision of the EM tracker, tracker calibration based on polynomial fitting and smooth filters, such as the Kalman filter, the moving average filter and the local regression filter, are deployed. RESULTS: From the experimental data analysis, as the distance between the transmitter and the sensor of the EM tracking system increases, the trueness and precision tend to decrease. The system's trueness and jitter errors can be modeled as the 3(rd) order polynomial error equations. After minimizing the positional error and applying smoothing filters, the mean value of error reduction is 36.9%. CONCLUSION: Our method can effectively reduce both positional systematic error and jitter error caused by EM field distortion. The method is successfully applied to calibrate an EM tracked surgical cautery tool.

The effect of augmented reality training on percutaneous needle placement in spinal facet joint injections.

The purpose of this study was to determine if augmented reality image overlay and laser guidance systems can assist medical trainees in learning the correct placement of a needle for percutaneous facet joint injection. The Perk Station training suite was used to conduct and record the needle insertion procedures. A total of 40 volunteers were randomized into two groups of 20. 1) The Overlay group received a training session that consisted of four insertions with image and laser guidance, followed by two insertions with laser overlay only. 2) The Control group received a training session of six classical freehand insertions. Both groups then conducted two freehand insertions. The movement of the needle was tracked during the series of insertions. The final insertion procedure was assessed to determine if there was a benefit to the overlay method compared to the freehand insertions. The Overlay group had a better success rate (83.3% versus 68.4%, p=0.002), and potential for less tissue damage as measured by the amount of needle movement inside the phantom (3077.6 mm(2) versus 5607.9 mm(2) , p =0.01). These results suggest that an augmented reality overlay guidance system can assist medical trainees in acquiring technical competence in a percutaneous needle insertion procedure.