Browsing by Subject "Equipment Failure"

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    ItemOpen Access
    Assessment of symptomatic rod fracture after posterior instrumented fusion for adult spinal deformity.
    (Neurosurgery, 2012-10) Smith, Justin S; Shaffrey, Christopher I; Ames, Christopher P; Demakakos, Jason; Fu, Kai-Ming G; Keshavarzi, Sassan; Li, Carol MY; Deviren, Vedat; Schwab, Frank J; Lafage, Virginie; Bess, Shay; International Spine Study Group

    Background

    Improved understanding of rod fracture (RF) in adult spinal deformity could be valuable for implant design, surgical planning, and patient counseling.

    Objective

    To evaluate symptomatic RF after posterior instrumented fusion for adult spinal deformity.

    Methods

    A multicenter, retrospective review of RF in adult spinal deformity was performed. Inclusion criteria were spinal deformity, age older than 18 years, and more than 5 levels posterior instrumented fusion. Rod failures were divided into early (≤12 months) and late (>12 months).

    Results

    Of 442 patients, 6.8% had symptomatic RF. RF rates were 8.6% for titanium alloy, 7.4% for stainless steel, and 2.7% for cobalt chromium. RF incidence after pedicle subtraction osteotomy (PSO) was 15.8%. Among patients with a PSO and RF, 89% had RF at or adjacent to the PSO. Mean time to early RF (63%) was 6.4 months (range, 2-12 months). Mean time to late RF (37%) was 31.8 months (range, 14-73 months). The majority of RFs after PSO (71%) were early (mean, 10 months). Among RF cases, mean sagittal vertical axis improved from preoperative (163 mm) to postoperative (76.9 mm) measures (P<.001); however, 16 had postoperative malalignment (sagittal vertical axis>50 mm; mean, 109 mm).

    Conclusion

    Symptomatic RF occurred in 6.8% of adult spinal deformity cases and in 15.8% of PSO patients. The rate of RF was lower with cobalt chromium than with titanium alloy or stainless steel. Early failure was most common after PSO and favored the PSO site, suggesting that RF may be caused by stress at the PSO site. Postoperative sagittal malalignment may increase the risk of RF.
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    ItemOpen Access
    Cable externalization and electrical failure of the Riata family of implantable cardioverter-defibrillator leads: A systematic review and meta-analysis.
    (Heart rhythm, 2015-06) Zeitler, Emily P; Pokorney, Sean D; Zhou, Ke; Lewis, Robert K; Greenfield, Ruth Ann; Daubert, James P; Matchar, David B; Piccini, Jonathan P

    Background

    The Riata class of defibrillator leads were placed under US Food and Drug Association (FDA) advisory as of November 2011 because of high rates of cable externalization (CE) and electrical failure (EF). The overall rates of these complications remain unknown.

    Objective

    The purpose of this study was to systematically search the literature for rates of Riata lead failure and to perform a meta-analysis to estimate failure rates.

    Methods

    We conducted a meta-analysis of observational studies examining the rates of EF, CE, and the interaction of the two. We identified 23 English language manuscripts addressing 1 or more of these questions.

    Results

    Across 23 studies, the overall CE rate was 23.1% (95% confidence interval [CI] 19.0%-27.6%). The overall EF rate was 6.3% (95% CI 4.7%-8.2%). The presence of CE was associated with a more than 6-fold increase in the rate of EF compared to no CE (17.3% [95% CI 11.2%-25.9%] vs 2.7% [95% CI 1.4%-5.2%], respectively). The rate of CE was 3-fold higher for 8Fr leads compared to 7Fr leads, but rates of EF were similar (4.6%; 95% CI 3.2-6.6] and 3.9%; 95% CI 2.4-6.1], respectively). Rates of both CE and EF were higher in dual coil vs single coil leads, but confidence intervals overlapped.

    Conclusion

    In clinical practice, rates of CE in Riata leads are substantial. While CE is associated with a significant increase in the risk of EF, the incidence of EF without externalization is not trivial.
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    ItemOpen Access
    Optimal management of Riata leads with no known electrical abnormalities or externalization: a decision analysis.
    (Journal of cardiovascular electrophysiology, 2015-02) Pokorney, Sean D; Zhou, Ke; Matchar, David B; Love, Sean; Zeitler, Emily P; Lewis, Robert; Piccini, Jonathan P

    Introduction

    Riata and Riata ST implantable cardioverter-defibrillator (ICD) leads (St. Jude Medical, Sylmar, CA, USA) can develop conductor cable externalization and/or electrical failure. Optimal management of these leads remains unknown.

    Methods and results

    A Markov model compared 4 lead management strategies: (1) routine device interrogation for electrical failure, (2) systematic yearly fluoroscopic screening and routine device interrogation, (3) implantation of new ICD lead with capping of the in situ lead, and (4) implantation of new ICD lead with extraction of the in situ lead. The base case was a 64-year-old primary prevention ICD patient. Modeling demonstrated average life expectancies as follows: capping with new lead implanted at 134.5 months, extraction with new lead implanted at 134.0 months, fluoroscopy with routine interrogation at 133.9 months, and routine interrogation at 133.5 months. One-way sensitivity analyses identified capping as the preferred strategy with only one parameter having a threshold value: when risk of nonarrhythmic death associated with lead abandonment is greater than 0.05% per year, lead extraction is preferred over capping. A second-order Monte Carlo simulation (n = 10,000), as a probabilistic sensitivity analysis, found that lead revision was favored with 100% certainty (extraction 76% and capping 24%).

    Conclusions

    Overall there were minimal differences in survival with monitoring versus active lead management approaches. There is no evidence to support fluoroscopic screening for externalization of Riata or Riata ST leads.