10 research outputs found
Effect of marker position and size on the registration accuracy of HoloLens in a non-clinical setting with implications for high-precision surgical tasks
Acknowledgments: We are grateful to Mike Whyment for the purchase of the holographic headset used in this study and to Rute Vieira and Fiona Saunders for their advice on statistics. We would also like to thank Denise Tosh and the Anatomy staff at the University of Aberdeen for their support. This research was funded by The Roland Sutton Academic Trust (RSAT 0053/R/17) and the University of Aberdeen (via an Elphinstone Scholarship, IKEC Award and Medical Sciences Honours project funding). Funding: This study was funded by The Roland Sutton Academic Trust (RSAT 0053/R/17) and the University of Aberdeen (via an Elphinstone Scholarship, IKEC Award and Medical Sciences Honours project funding).Peer reviewedPublisher PD
Augmented reality headsets for surgical guidance: the impact of holographic model positions on user localisation accuracy
Novel augmented reality headsets such as HoloLens can be used to overlay patient-specific virtual models of resection margins on the patient’s skin, providing surgeons with information not normally available in the operating room. For this to be useful, surgeons wearing the headset must be able to localise virtual models accurately. We measured the error with which users localise virtual models at different positions and distances from their eyes. Healthy volunteers aged 20-59 years (n = 54) performed 81 exercises involving the localisation of a virtual hexagon’s vertices overlaid on a monitor surface. Nine predefined positions and three distances between the virtual hexagon and the users’ eyes (65, 85 and 105 cm) were set. We found that some model positions and the shortest distance (65 cm) led to larger localisation errors than other positions and larger distances (85 and 105 cm). Positional errors of more than 5 mm and 1-5 mm margin errors were found in 29.8% and over 40% of cases, respectively. Strong outliers were also found (e.g., margin shrinkage of up to 17.4 mm in 4.3% of cases).
The measured errors may result in poor outcomes of surgeries: e.g., incomplete tumour excision or inaccurate flap design, which can potentially lead to tumour recurrence and flap failure, respectively. Reducing localisation errors associated with arm-reach distances between the virtual models and users’ eyes is necessary for augmented reality headsets to be suitable for surgical purposes. In addition, training surgeons on the use of these headsets may help to minimise localisation errors
Holographic displays: the next revolution in augmented-reality-guided surgery?
Augmented Reality (AR) applied to surgical guidance is becoming increasingly important. The overlay of patient-specific 3D models onto the patient’s body surface provides access to information not normally available during surgery. Recent advances in tracking and display technologies open new opportunities to develop more efficient AR-guided surgery systems. To understand the current state of AR-guided surgery, we reviewed publications on systems which overlay virtual data onto patients. Our research shows that these systems have been used for numerous applications, e.g. to locate tumours or visualise the correct position of implants. However, many of these systems are technically complex and present poor ergonomics and limited accuracy. Novel holographic Head Mounted Displays (HMDs) which integrate tracking and registration technology (e.g. Microsoft HoloLens® or Magic Leap®) and Software Development Kits (SDKs) help to overcome these shortcomings: holographic HMDs have reduced technical complexity and improved ergonomics and the release of SDKs in recent years has allowed for a wide range of users to easily create AR applications. Their combined use can, therefore, facilitate the implementation of more sophisticated AR-guided surgery systems in the operating room. However, maximising surgical accuracy still remains a challenge for manufacturers and researchers
Effects of Bipolar Radiofrequency on Collagen Synthesis from Patients with Brachial Ptosis
Background:. Radiofrequency is frequently used for skin rejuvenation, localized fat elimination and cellulite treatment. It prompts the expression of thermal shock proteins that lead to dermal thickening as a result of collagen synthesis. The authors report a histological and clinical analysis of the arm subdermal changes before and after bipolar radiofrequency treatment plus liposuction to determine their benefits for arm contouring.
Methods:. Inclusion criteria included patients with stage 1, 2a, and 2b brachial ptosis (Duncan classification) and upper limb fat deposits who were considered candidates for third-generation ultrasound-assisted liposculpture plus radiofrequency-assisted lipolysis/skin tightening. Arm subdermal tissue samples (5 mm³) were analyzed before and after the intervention. We used 10% formaldehyde for tissue fixation and stained each sample with hematoxylin/eosin, Masson trichrome, and antibody markers against the cell cycle Ki-67 protein.
Results:. We analyzed a total of 12 biopsies from six patients who meet the inclusion/exclusion criteria. Histological findings with hematoxylin/eosin revealed hyperplastic and metaplastic changes with focal distribution within the papillary and reticular dermis. Masson trichrome staining showed an increase of the characteristic basophilia of thin type-I and type-III collagen fibers. In contrast, molecular analysis reported an increase in fibroblast activity mediated by the activation of the heat shock protein HSP47.
Conclusion:. Radiofrequency may be a great alternative to improve skin retraction in patients with mild to moderate brachial dermatochalasis through the activation of HSP47 heat shock protein and the production of type-I and type-III collagen
Recovery of dialysis patients with COVID-19: health outcomes 3 months after diagnosis in ERACODA
© The Author(s) 2022.Background. Coronavirus disease 2019 (COVID-19)-related short-term mortality is high in dialysis patients, but longer-term outcomes are largely unknown. We therefore assessed patient recovery in a large cohort of dialysis patients 3 months after their COVID-19 diagnosis. Methods. We analyzed data on dialysis patients diagnosed with COVID-19 from 1 February 2020 to 31 March 2021 from the European Renal Association COVID-19 Database (ERACODA). The outcomes studied were patient survival, residence and functional and mental health status (estimated by their treating physician) 3 months after COVID-19 diagnosis. Complete follow-up data were available for 854 surviving patients. Patient characteristics associated with recovery were analyzed using logistic regression. Results. In 2449 hemodialysis patients (mean ± SD age 67.5 ± 14.4 years, 62% male), survival probabilities at 3 months after COVID-19 diagnosis were 90% for nonhospitalized patients (n = 1087), 73% for patients admitted to the hospital but not to an intensive care unit (ICU) (n = 1165) and 40% for those admitted to an ICU (n = 197). Patient survival hardly decreased between 28 days and 3 months after COVID-19 diagnosis. At 3 months, 87% functioned at their pre-existent functional and 94% at their pre-existent mental level. Only few of the surviving patients were still admitted to the hospital (0.8–6.3%) or a nursing home (∼5%). A higher age and frailty score at presentation and ICU admission were associated with worse functional outcome. Conclusions. Mortality between 28 days and 3 months after COVID-19 diagnosis was low and the majority of patients who survived COVID-19 recovered to their pre-existent functional and mental health level at 3 months after diagnosis
Association of obesity with 3-month mortality in kidney failure patients with COVID-19
Background: In the general population with coronavirus disease 2019 (COVID-19), obesity is associated with an increased risk of mortality. Given the typically observed obesity paradox among patients on kidney function replacement therapy (KFRT), especially dialysis patients, we examined the association of obesity with mortality among dialysis patients or living with a kidney transplant with COVID-19. Methods: Data from the European Renal Association COVID-19 Database (ERACODA) were used. KFRT patients diagnosed with COVID-19 between 1 February 2020 and 31 January 2021 were included. The association of Quetelet's body mass index (BMI) (kg/m2), divided into: <18.5 (lean), 18.5-24.9 (normal weight), 25-29.9 (overweight), 30-34.9 (obese I) and ≥35 (obese II/III), with 3-month mortality was investigated using Cox proportional-hazards regression analyses. Results: In 3160 patients on KFRT (mean age: 65 years, male: 61%), 99 patients were lean, 1151 normal weight (reference), 1160 overweight, 525 obese I and 225 obese II/III. During follow-up of 3 months, 28, 20, 21, 23 and 27% of patients died in these categories, respectively. In the fully adjusted model, the hazard ratios (HRs) for 3-month mortality were 1.65 [95% confidence interval (CI): 1.10, 2.47], 1 (ref.), 1.07 (95% CI: 0.89, 1.28), 1.17 (95% CI: 0.93, 1.46) and 1.71 (95% CI: 1.27, 2.30), respectively. Results were similar among dialysis patients (N = 2343) and among those living with a kidney transplant (N = 817) (Pinteraction = 0.99), but differed by sex (Pinteraction = 0.019). In males, the HRs for the association of aforementioned BMI categories with 3-month mortality were 2.07 (95% CI: 1.22, 3.52), 1 (ref.), 0.97 (95% CI: 0.78. 1.21), 0.99 (95% CI: 0.74, 1.33) and 1.22 (95% CI: 0.78, 1.91), respectively, and in females corresponding HRs were 1.34 (95% CI: 0.70, 2.57), 1 (ref.), 1.31 (95% CI: 0.94, 1.85), 1.54 (95% CI: 1.05, 2.26) and 2.49 (95% CI: 1.62, 3.84), respectively. Conclusion: In KFRT patients with COVID-19, on dialysis or a kidney transplant, obesity is associated with an increased risk of mortality at 3 months. This is in contrast to the obesity paradox generally observed in dialysis patients. Additional studies are required to corroborate the sex difference in the association of obesity with mortality
Clinical, Functional, and Mental Health Outcomes in Kidney Transplant Recipients 3 Months after a Diagnosis of COVID-19
Background. Kidney transplant patients are at high risk for coronavirus disease 2019 (COVID-19)-related mortality. However, limited data are available on longer-term clinical, functional, and mental health outcomes in patients who survive COVID-19. Methods. We analyzed data from adult kidney transplant patients in the European Renal Association COVID-19 Database who presented with COVID-19 between February 1, 2020, and January 31, 2021. Results. We included 912 patients with a mean age of 56.7 (±13.7) y. 26.4% were not hospitalized, 57.5% were hospitalized without need for intensive care unit (ICU) admission, and 16.1% were hospitalized and admitted to the ICU. At 3 mo follow-up survival was 82.3% overall, and 98.8%, 84.2%, and 49.0%, respectively, in each group. At 3 mo follow-up biopsy-proven acute rejection, need for renal replacement therapy, and graft failure occurred in the overall group in 0.8%, 2.6%, and 1.8% respectively, and in 2.1%, 10.6%, and 10.6% of ICU-admitted patients, respectively. Of the surviving patients, 83.3% and 94.4% reached their pre-COVID-19 physician-reported functional and mental health status, respectively, within 3 mo. Of patients who had not yet reached their prior functional and mental health status, their treating physicians expected that 79.6% and 80.0%, respectively, still would do so within the coming year. ICU admission was independently associated with a low likelihood to reach prior functional and mental health status. Conclusions. In kidney transplant recipients alive at 3-mo follow-up, clinical, physician-reported functional, and mental health recovery was good for both nonhospitalized and hospitalized patients. Recovery was, however, less favorable for patients who had been admitted to the ICU
Sex differences in COVID-19 mortality risk in patients on kidney function replacement therapy
© 2022, The Author(s).In the general population with COVID-19, the male sex is an established risk factor for mortality, in part due to a more robust immune response to COVID-19 in women. Because patients on kidney function replacement therapy (KFRT) have an impaired immune response, especially kidney transplant recipients due to their use of immunosuppressants, we examined whether the male sex is still a risk factor for mortality among patients on KFRT with COVID-19. From the European Renal Association COVID-19 Database (ERACODA), we examined patients on KFRT with COVID-19 who presented between February 1st, 2020, and April 30th, 2021. 1204 kidney transplant recipients (male 62.0%, mean age 56.4 years) and 3206 dialysis patients (male 61.8%, mean age 67.7 years) were examined. Three-month mortality in kidney transplant recipients was 16.9% in males and 18.6% in females (p = 0.31) and in dialysis patients 27.1% in males and 21.9% in females (p = 0.001). The adjusted HR for the risk of 3-month mortality in males (vs females) was 0.89 (95% CI 65, 1.23, p = 0.49) in kidney transplant recipients and 1.33 (95% CI 1.13, 1.56, p = 0.001) in dialysis patients (pinteraction = 0.02). In a fully adjusted model, the aHR for the risk of 3-month mortality in kidney transplant recipients (vs. dialysis patients) was 1.39 (95% CI 1.02, 1.89, p = 0.04) in males and 2.04 (95% CI 1.40, 2.97, p < 0.001) in females (pinteraction = 0.02). In patients on KFRT with COVID-19, the male sex is not a risk factor for mortality among kidney transplant recipients but remains a risk factor among dialysis patients. The use of immunosuppressants in kidney transplant recipients, among other factors, may have narrowed the difference in the immune response to COVID-19 between men and women, and therefore reduced the sex difference in COVID-19 mortality risk
Sex differences in COVID-19 mortality risk in patients on kidney function replacement therapy
In the general population with COVID-19, the male sex is an established risk factor for mortality, in part due to a more robust immune response to COVID-19 in women. Because patients on kidney function replacement therapy (KFRT) have an impaired immune response, especially kidney transplant recipients due to their use of immunosuppressants, we examined whether the male sex is still a risk factor for mortality among patients on KFRT with COVID-19. From the European Renal Association COVID-19 Database (ERACODA), we examined patients on KFRT with COVID-19 who presented between February 1st, 2020, and April 30th, 2021. 1204 kidney transplant recipients (male 62.0%, mean age 56.4 years) and 3206 dialysis patients (male 61.8%, mean age 67.7 years) were examined. Three-month mortality in kidney transplant recipients was 16.9% in males and 18.6% in females (p = 0.31) and in dialysis patients 27.1% in males and 21.9% in females (p = 0.001). The adjusted HR for the risk of 3-month mortality in males (vs females) was 0.89 (95% CI 65, 1.23, p = 0.49) in kidney transplant recipients and 1.33 (95% CI 1.13, 1.56, p = 0.001) in dialysis patients (pinteraction = 0.02). In a fully adjusted model, the aHR for the risk of 3-month mortality in kidney transplant recipients (vs. dialysis patients) was 1.39 (95% CI 1.02, 1.89, p = 0.04) in males and 2.04 (95% CI 1.40, 2.97, p < 0.001) in females (pinteraction = 0.02). In patients on KFRT with COVID-19, the male sex is not a risk factor for mortality among kidney transplant recipients but remains a risk factor among dialysis patients. The use of immunosuppressants in kidney transplant recipients, among other factors, may have narrowed the difference in the immune response to COVID-19 between men and women, and therefore reduced the sex difference in COVID-19 mortality risk
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Global impact of COVID-19 on stroke care
BACKGROUND: The COVID-19 pandemic led to profound changes in the organization of health care systems worldwide. AIMS: We sought to measure the global impact of the COVID-19 pandemic on the volumes for mechanical thrombectomy, stroke, and intracranial hemorrhage hospitalizations over a three-month period at the height of the pandemic (1 March-31 May 2020) compared with two control three-month periods (immediately preceding and one year prior). METHODS: Retrospective, observational, international study, across 6 continents, 40 countries, and 187 comprehensive stroke centers. The diagnoses were identified by their ICD-10 codes and/or classifications in stroke databases at participating centers. RESULTS: The hospitalization volumes for any stroke, intracranial hemorrhage, and mechanical thrombectomy were 26,699, 4002, and 5191 in the three months immediately before versus 21,576, 3540, and 4533 during the first three pandemic months, representing declines of 19.2% (95%CI, -19.7 to -18.7), 11.5% (95%CI, -12.6 to -10.6), and 12.7% (95%CI, -13.6 to -11.8), respectively. The decreases were noted across centers with high, mid, and low COVID-19 hospitalization burden, and also across high, mid, and low volume stroke/mechanical thrombectomy centers. High-volume COVID-19 centers (-20.5%) had greater declines in mechanical thrombectomy volumes than mid- (-10.1%) and low-volume (-8.7%) centers (p < 0.0001). There was a 1.5% stroke rate across 54,366 COVID-19 hospitalizations. SARS-CoV-2 infection was noted in 3.9% (784/20,250) of all stroke admissions. CONCLUSION: The COVID-19 pandemic was associated with a global decline in the volume of overall stroke hospitalizations, mechanical thrombectomy procedures, and intracranial hemorrhage admission volumes. Despite geographic variations, these volume reductions were observed regardless of COVID-19 hospitalization burden and pre-pandemic stroke/mechanical thrombectomy volumes.status: publishe