A periodic maintenance policy through either an imperfect repair or replacement is proposed for a repairable system. It is assumed that the system is subject to an inverse Gaussian degradation process. The effect of imperfect repair is modelled through both arithmetic reduction of degradation and arithmetic reduction of age approaches. The degradation level of the system is measured after each imperfect repair in periodic time intervals. The system is replaced if its deterioration level exceeds a pre-determined technical threshold or at the nth inspection time, whichever occurs first. The main goal of the paper is to find the optimal value of n based on expected cost rate function. Some theoretical results are derived and then the optimal policy is obtained numerically. The effect of imperfect repair, the inspection time interval, the value of technical degradation threshold, and the costs of interest are all studied on the optimal policy.

Background: Successful repair of a torn rotator cuff may prevent progression to rotator cuff arthropathy. However, previous studies have shown a substantial rate of failure after rotator cuff repair and characteristics of surgically repaired rotator cuffs that go on to shoulder arthroplasty have not been fully elucidated. The purpose of this study was to determine the patient characteristics and rate at which patients who underwent rotator cuff repair progressed to shoulder arthroplasty. Methods: This was a retrospective study of patients who underwent rotator cuff repair in a large, closed healthcare system in 2008. The EMR was queried for rotator cuff repair CPT with ICD-9 codes for rotator cuff. The resultant dataset was then cross-referenced with a separate internal shoulder arthroplasty registry to determine which patients went onto shoulder arthroplasty. Demographic variables, descriptors of tear pathology and repair characteristics were collected and compared between patients who subsequently underwent shoulder arthroplasty and those that did not. Results: A total of 882 rotator cuff repair patients were included within this study. Of the initial 882 cuff Repairs, there were 12 patients (1. 4%) that went on to have arthroplasty. Patients who underwent shoulder arthroplasty after rotator cuff repair were significantly older at time of surgery and had greater comorbidity burdens. Patients who ended up with shoulder arthroplasty had the procedure an average of 4. 77 ± 3. 28 (SD) years after rotator cuff repair, with 11 of 12 patients having a diagnosis of rotator cuff arthropathy at the time of shoulder replacement. Conclusion: In a closed system, tracking rotator cuff Repairs over 9. 1 years revealed a small number that went on to subsequent shoulder arthroplasty. Patients who underwent shoulder arthroplasty were significantly older and had greater comorbidity burdens than those who did not. Patients who underwent shoulder arthroplasty usually either had shoulder arthroplasty within 1 year or after 5 years. Enhanced understanding of which patients may progress to arthroplasty may provide a better initial choice of operative intervention in those patients.

Background: Appendectomy is one of the most common abdominal operations. The prevalence of appendicitis increases with increased lymphatic tissue with the maximum prevalence at the beginning of adulthood. Owing to the high prevalence of appendectomy, patients will be benefited from a better method with improvement of surgical site and management of postoperative pain and infection. Subcuticular repair method due to better scar formation and less pain is preferred to the routine repair method, if the infection rate is comparable.Methods: The current study was conducted on appendectomy candidates in 2017. After providing the necessary explanations, the interested patients signed the informed consent forms and voluntarily participated in the study. The subjects were randomly assigned into two groups of randomized clinical trial with parallel design and 1: 1 ratio. The sample size was 120 individuals based on previous studies. Subjects were assigned into two groups of 105 subjects each: the first group as subcuticular and the second group as transdermal accordingly. Then, they were studied and followed up.Results: One week after operation, 8.5% of subcuticular and 5.7% of transdermal Repairs developed localized infection, and no significant difference was observed between the two groups. One week after surgery in the first group, 10% had no pain, 36% mild pain, 27% moderate pain, and 27% severe pain. In the second group, 7% had no pain, 36% mild pain, 30% moderate pain, and 27% severe pain. Therefore, there was no significant difference between two groups in this regard.Conclusion: There was no significant difference in the surgical wound infection rate between two methods. Accordingly, subcuticular repair was suggested as the preferred method owing to its better scar formation.