The risk analysis of perioperative complications of cementless hip arthroplasty in octogenarians.

INTRODUCTION: Hip arthroplasty is exposed to demographic change as patients age. Analysis of risk factors for surgical treatment decisions in the group of ≥ 80-year-old patients is crucial. Healthcare systems in developed countries are being tested medically and financially by the ageing population. Therefore, this study analysed the perioperative complications of cementless primary hip arthroplasty in octogenarians and compared them with patients aged ≤ 60 years. METHODS: A retrospective data analysis of the year 2017 was done in a maximum care hospital of General Orthopaedic Surgery. Patients aged ≥ 80 years or ≤ 60 years with primary cementless hip arthroplasty were included. The outcome of interest was surgery-related and systemic complications, the development of haemoglobin and the incidence of blood transfusion after cementless primary hip arthroplasty in octogenarians during the hospitalisation and the follow-up treatment. Chi-square tests and Fischer's exact test were used for nominal variables. The two-factorial variance analysis-mixed model was used for Hb analyses and the Welch test for group comparison for metric parameters. RESULTS: There was a significantly increased incidence of systemic complications during hospitalisation in the ≥ 80-year-old patients (phi 0.26; Std. Ri - 0.8 (A), 2.2 (B); p = 0.007), as well as a significantly increased rate of blood transfusions (phi 0.403; Std. Ri - 1.3 (A), 3.2 (B); p = < 0.001). No clustered pre-existing conditions in the ≥ 80-year-old patients pointed out a significant association with the incidence of systemic complications. Surgery-related complications showed no significant difference during hospitalisation and follow-up treatment. CONCLUSION: The study reveals that primary cementless hip prosthesis implantation is a safe procedure without increased incidence of surgery-related complications. Increased attention should be paid to interdisciplinary preoperative optimisation (adjustment of blood pressure, blood transfusions, if necessary, safe exclusion of urinary tract infections) and postoperative care of octogenarians (tight laboratory examinations, geriatric co-attendance).

Physics-aware learning and domain-specific loss design in ophthalmology.

The human cataract, a developing opacification of the human eye lens, currently constitutes the world's most frequent cause for blindness. As a result, cataract surgery has become the most frequently performed ophthalmic surgery in the world. By removing the human lens and replacing it with an artificial intraocular lens (IOL), the optical system of the eye is restored. In order to receive a good refractive result, the IOL specifications, especially the refractive power, have to be determined precisely prior to surgery. In the last years, there has been a body of work to perform this prediction by using biometric information extracted from OCT imaging data, recently also by machine learning (ML) methods. Approaches so far consider only biometric information or physical modelling, but provide no effective combination, while often also neglecting IOL geometry. Additionally, ML on small data sets without sufficient domain coverage can be challenging. To solve these issues, we propose OpticNet, a novel optical refraction network based on an unsupervised, domain-specific loss function that explicitly incorporates physical information into the network. By providing a precise and differentiable light propagation eye model, physical gradients following the eye optics are backpropagated into the network. We further propose a new transfer learning procedure, which allows the unsupervised pre-training on the optical model and fine-tuning of the network on small amounts of surgical patient data. We show that our method outperforms the current state of the art on five OCT-image based data sets, provides better domain coverage within its predictions, and achieves better physical consistency.

Prediction of postoperative intraocular lens tilt using swept-source optical coherence tomography.

PURPOSE: To compare crystalline lens tilt in eyes before and intraocular lens (IOL) tilt in eyes after cataract surgery using swept-source optical coherence tomography (SS-OCT) (IOLMaster 700). SETTING: Hanusch Hospital, Vienna, Austria. DESIGN: Prospective case series. METHODS: Patients' eyes were scanned 1 week before and 2 months after cataract surgery with IOL implantation using an SS-OCT device. This device performs B-scans along 6 meridians (0, 30, 60, 90, 120, and 150 degrees) to determine lens and IOL tilt. RESULTS: Sixty-two eyes (62 patients) were included in the analysis. The mean magnitude and direction of tilt showed mirror symmetry between both eyes along the vertical axis and a primarily nasal outward tilt for right eyes and left eyes. The mean tilt was 4.3 degrees at 15.8 degrees preoperatively and 6.2 degrees at 16.8 degrees postoperatively. The mean direction of crystalline lens tilt preoperatively and IOL tilt postoperatively showed a strong correlation (R = 0.71), whereas the mean magnitude of tilt showed a weaker correlation (R = 0.37). The direction and magnitude of tilt of the crystalline lens and IOL eyes were normally distributed around similar values before and after surgery. CONCLUSIONS: The correlations between crystalline lens tilt and IOL tilt using whole-eye scanning indicate that preoperative tilt determination using SS-OCT could help predict postoperative IOL tilt, assist in IOL (toric) power calculations, and potentially improve visual outcomes.