All Publications

  • Normative data of a smartphone app-based 6-minute walking test, test-retest reliability, and content validity with patient-reported outcome measures. Journal of neurosurgery. Spine Tosic, L., Goldberger, E., Maldaner, N., Sosnova, M., Zeitlberger, A. M., Staartjes, V. E., Gadjradj, P. S., Eversdijk, H. A., Quddusi, A., Gandía-González, M. L., Sayadi, J. J., Desai, A., Regli, L., Gautschi, O. P., Stienen, M. N. 2020: 1–10


    The 6-minute walking test (6WT) is used to determine restrictions in a subject's 6-minute walking distance (6WD) due to lumbar degenerative disc disease. To facilitate simple and convenient patient self-measurement, a free and reliable smartphone app using Global Positioning System coordinates was previously designed. The authors aimed to determine normative values for app-based 6WD measurements.The maximum 6WD was determined three times using app-based measurement in a sample of 330 volunteers without previous spine surgery or current spine-related disability, recruited at 8 centers in 5 countries (mean subject age 44.2 years, range 16-91 years; 48.5% male; mean BMI 24.6 kg/m2, range 16.3-40.2 kg/m2; 67.9% working; 14.2% smokers). Subjects provided basic demographic information, including comorbidities and patient-reported outcome measures (PROMs): visual analog scale (VAS) for both low-back and lower-extremity pain, Core Outcome Measures Index (COMI), Zurich Claudication Questionnaire (ZCQ), and subjective walking distance and duration. The authors determined the test-retest reliability across three measurements (intraclass correlation coefficient [ICC], standard error of measurement [SEM], and mean 6WD [95% CI]) stratified for age and sex, and content validity (linear regression coefficients) between 6WD and PROMs.The ICC for repeated app-based 6WD measurements was 0.89 (95% CI 0.87-0.91, p < 0.001) and the SEM was 34 meters. The overall mean 6WD was 585.9 meters (95% CI 574.7-597.0 meters), with significant differences across age categories (p < 0.001). The 6WD was on average about 32 meters less in females (570.5 vs 602.2 meters, p = 0.005). There were linear correlations between average 6WD and VAS back pain, VAS leg pain, COMI Back and COMI subscores of pain intensity and disability, ZCQ symptom severity, ZCQ physical function, and ZCQ pain and neuroischemic symptoms subscores, as well as with subjective walking distance and duration, indicating that subjects with higher pain, higher disability, and lower subjective walking capacity had significantly lower 6WD (all p < 0.001).This study provides normative data for app-based 6WD measurements in a multicenter sample from 8 institutions and 5 countries. These values can now be used as reference to compare 6WT results and quantify objective functional impairment in patients with degenerative diseases of the spine using z-scores. The authors found a good to excellent test-retest reliability of the 6WT app, a low area of uncertainty, and high content validity of the average 6WD with commonly used PROMs.

    View details for DOI 10.3171/2020.3.SPINE2084

    View details for PubMedID 32470938

  • Novel Assistive Dress Shoe & Footwear Needs Analysis for Patients with Parkinson's Disease Sayadi, L., Sayadi, J., Chopan, M., Fijany, A., Hermanowicz, N. LIPPINCOTT WILLIAMS & WILKINS. 2019
  • The New Frontier: A Review of Augmented Reality and Virtual Reality in Plastic Surgery. Aesthetic surgery journal Sayadi, L. R., Naides, A., Eng, M., Fijany, A., Chopan, M., Sayadi, J. J., Shaterian, A., Banyard, D. A., Evans, G. R., Vyas, R., Widgerow, A. D. 2019


    Mixed reality, a blending of the physical and digital worlds, can enhance the surgical experience, leading to greater precision, efficiency and improved outcomes. Various studies across different disciplines have reported encouraging results using mixed reality technologies, such as augmented and virtual reality. To provide a better understanding of the applications and limitations of this technology in plastic surgery, we performed a systematic review of the literature in accordance with PRISMA guidelines. The initial query of the NCBI database yielded 2,544 results, and only 46 articles met our inclusion criteria. The majority of studies were in the field of craniofacial surgery, and uses of mixed reality included preoperative planning, intraoperative guides and education of surgical trainees. A deeper understanding of mixed reality technologies may promote its integration, and also help inspire new and creative applications in healthcare.

    View details for DOI 10.1093/asj/sjz043

    View details for PubMedID 30753313

  • Assessing and addressing footwear needs in Parkinson's disease-design thinking in neurology. NeuroRehabilitation Sayadi, J., Sayadi, L. R., Fijany, A., Chopan, M., Hermanowicz, N. 2019


    Parkinson's disease (PD) is a neurodegenerative movement disorder that results in a variety of motor deficits such as unsteady gait, bradykinesia, resting tremor, and rigidity.The objective of this study was to quantify and assess the challenges and preferences Parkinson's disease patients have regarding footwear.A 13-question survey was designed to assess footwear challenges and preferences among PD patients. A total of 89 PD patients, both male and female, were surveyed in the outpatient setting at UC Irvine during their appointments with the senior author.A majority of the PD patients in our cohort (64%) reported experiencing difficulties wearing shoes on their own. Patients who experienced difficulties wearing shoes were significantly more likely to report having been forced to make changes to their desired outfits (p = 0.0011), choosing not to wear dress shoes due to their discomfort (p = 0.0175), and preferring shoes without laces (p = 0.0 048).The present study is the first attempt to use a survey to quantify the challenges and preferences reported by PD patients in regard to their usage of footwear. Inspired by our findings, the study team designed a novel dress shoe prototype that may address some of the difficulties and concerns gathered through our survey.

    View details for DOI 10.3233/NRE-192897

    View details for PubMedID 31884494

  • The Molecular Pathogenesis of Dupuytren Disease: Review of the Literature and Suggested New Approaches to Treatment. Annals of plastic surgery Sayadi, L. R., Alhunayan, D., Sarantopoulos, N., Kong, C., Condamoor, S., Sayadi, J., Banyard, D. A., Shaterian, A., Leis, A., Evans, G. R., Widgerow, A. D. 2019


    Ever since the classification of Dupuytren disease into the proliferative, involutional, and residual stages, extensive research has been performed to uncover the molecular underpinnings of the disease and develop better treatment modalities for patients. The aim of this article is to systematically review the basic science literature pertaining to Dupuytren disease and suggest a new approach to treatment.Following Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, a systematic review was conducted using the MEDLINE database to identify basic science literature on Dupuytren pathophysiology falling under 1 or more of the following categories: (1) Molecular alterations, (2) Structural alterations, and (3) Genetic predisposition.A total of 177 articles were reviewed of which 77 studies met inclusion criteria. Articles were categorized into respective sections outlined in the study methods.The pathophysiological changes involved in Dupuytren's disease can be divided into a number of molecular and structural alterations with genetic predisposition playing a contributory role. Understanding these changes can allow for the development of biologics which may disrupt and halt the disease process.

    View details for DOI 10.1097/SAP.0000000000001918

    View details for PubMedID 31232804

  • Sequence features associated with the cleavage efficiency of CRISPR/Cas9 system SCIENTIFIC REPORTS Liu, X., Homma, A., Sayadi, J., Yang, S., Ohashi, J., Takumi, T. 2016; 6: 19675


    The CRISPR-Cas9 system has recently emerged as a versatile tool for biological and medical research. In this system, a single guide RNA (sgRNA) directs the endonuclease Cas9 to a targeted DNA sequence for site-specific manipulation. In addition to this targeting function, the sgRNA has also been shown to play a role in activating the endonuclease activity of Cas9. This dual function of the sgRNA likely underlies observations that different sgRNAs have varying on-target activities. Currently, our understanding of the relationship between sequence features of sgRNAs and their on-target cleavage efficiencies remains limited, largely due to difficulties in assessing the cleavage capacity of a large number of sgRNAs. In this study, we evaluated the cleavage activities of 218 sgRNAs using in vitro Surveyor assays. We found that nucleotides at both PAM-distal and PAM-proximal regions of the sgRNA are significantly correlated with on-target efficiency. Furthermore, we also demonstrated that the genomic context of the targeted DNA, the GC percentage, and the secondary structure of sgRNA are critical factors contributing to cleavage efficiency. In summary, our study reveals important parameters for the design of sgRNAs with high on-target efficiencies, especially in the context of high throughput applications.

    View details for DOI 10.1038/srep19675

    View details for Web of Science ID 000368737200001

    View details for PubMedID 26813419

    View details for PubMedCentralID PMC4728555

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