ABSTRACT
Background: Individuals who rely on wheelchairs, walkers, and crutches for ambulation have an increased incidence of rotator cuff tears due to altered shoulder biomechanics and increased force transmission across the shoulder joint. The purpose of our study is to review our longitudinal outcomes treating upper extremity ambulators to guide patient expectations and identify risk factors for rotator cuff repair failure. Methods: A total of fifteen patients were included after a cohort of thirty-nine patients were identified. The mean age was 54.9 years at the time of index rotator cuff repair, with each patient requiring either wheelchair, cane, walker, or crutches for ambulation. Clinical outcomes were measured (strength, range of motion, and pain scores), and patient-reported outcome scores (American Shoulder and Elbow Surgeons, Simple Shoulder Test, and University of California Los Angeles functional shoulder assessment tool) were obtained. No follow-up imaging was obtained unless indicated by a change in clinical status. Results: Within our cohort, 14 of 15 (93%) presented with supraspinatus tears, 7 of 15 (47%) with infraspinatus tears, and only 3 of 15 (20%) with subscapularis pathology. Additionally, the rates of concurrent biceps pathology or acromioclavicular joint pathology were significant at 53% and 73%, respectively. Only one patient in our cohort experienced known failure of cuff repair, despite longitudinal follow-up at an average of 97 months following surgery, however, routine follow-up imaging was not obtained. There were statistically significant improvements in visual analog scale pain scores, forward flexion ROM and strength, and abduction ROM. Additionally, statistically significant improvements were noted in all patient-reported outcome scores measured. Conclusion: Despite the apparent risks associated in rotator cuff repair in upper extremity ambulators, these patients demonstrate clinically significant improvements following surgery. Appreciating additional pathology beyond the rotator cuff is important in formulating a treatment plan.
ABSTRACT
Multielectrode array (MEA) technology has been extensively used for field potential recordings from excitable cells. However, its application for action potential (AP) measurements has not been harnessed. Here, we report a novel platform for high-resolution intracellular AP recordings from induced pluripotent stem cell-cardiomyocyte constructs derived from human cardiac fibroblasts. To gain intracellular access, micro-gold MEAs were used to electroporate multiple constructs simultaneously. High-throughput AP measurements were obtained from 41 multicellular constructs. Repeated electroporations of the same cells did not affect the signal stability. Our model has the capability to distinguish subtle differences in AP morphology to characterize the network profile. Furthermore, we confirm the reliability of the system by recapitulating known drug-induced physiological and arrhythmogenic responses. Overall, the model provides a unique cardio-electronic interface for non-invasive measurements of AP dynamics for drug screening and disease modeling. This technology opens the door for identifying novel cardio-factors to enhance electrophysiological maturation.
