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Dive into the research topics where John E. Ziewacz is active.

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Featured researches published by John E. Ziewacz.


The New England Journal of Medicine | 2013

Simulation-based trial of surgical-crisis checklists.

Alexander F. Arriaga; Angela M. Bader; Judith M. Wong; Stuart R. Lipsitz; William R. Berry; John E. Ziewacz; David L. Hepner; Daniel J. Boorman; Charles N. Pozner; Douglas S. Smink; Atul A. Gawande

BACKGROUND Operating-room crises (e.g., cardiac arrest and massive hemorrhage) are common events in large hospitals but can be rare for individual clinicians. Successful management is difficult and complex. We sought to evaluate a tool to improve adherence to evidence-based best practices during such events. METHODS Operating-room teams from three institutions (one academic medical center and two community hospitals) participated in a series of surgical-crisis scenarios in a simulated operating room. Each team was randomly assigned to manage half the scenarios with a set of crisis checklists and the remaining scenarios from memory alone. The primary outcome measure was failure to adhere to critical processes of care. Participants were also surveyed regarding their perceptions of the usefulness and clinical relevance of the checklists. RESULTS A total of 17 operating-room teams participated in 106 simulated surgical-crisis scenarios. Failure to adhere to lifesaving processes of care was less common during simulations when checklists were available (6% of steps missed when checklists were available vs. 23% when they were unavailable, P<0.001). The results were similar in a multivariate model that accounted for clustering within teams, with adjustment for institution, scenario, and learning and fatigue effects (adjusted relative risk, 0.28; 95% confidence interval, 0.18 to 0.42; P<0.001). Every team performed better when the crisis checklists were available than when they were not. A total of 97% of the participants reported that if one of these crises occurred while they were undergoing an operation, they would want the checklist used. CONCLUSIONS In a high-fidelity simulation study, checklist use was associated with significant improvement in the management of operating-room crises. These findings suggest that checklists for use during operating-room crises have the potential to improve surgical care. (Funded by the Agency for Healthcare Research and Quality.).


Journal of The American College of Surgeons | 2011

Crisis Checklists for the Operating Room: Development and Pilot Testing

John E. Ziewacz; Alexander F. Arriaga; Angela M. Bader; William R. Berry; Lizabeth Edmondson; Judith M. Wong; Stuart R. Lipsitz; David L. Hepner; Sarah E. Peyre; Steven Nelson; Daniel J. Boorman; Douglas S. Smink; Stanley W. Ashley; Atul A. Gawande

BACKGROUND Because operating room crises are rare events, failure to adhere to critical management steps is common. We sought to develop and pilot a tool to improve adherence to lifesaving measures during operating room crises. STUDY DESIGN We identified 12 of the most frequently occurring operating room crises and corresponding evidence-based metrics of essential care for each (46 total process measures). We developed checklists for each crisis based on a previously defined method, which included literature review, multidisciplinary expert consultation, and simulation. After development, 2 operating room teams (11 participants) were each exposed to 8 simulations with random assignment to checklist use or working from memory alone. Each team managed 4 simulations with a checklist available and 4 without. One of the primary outcomes measured through video review was failure to adhere to essential processes of care. Participants were surveyed for perceptions of checklist use and realism of the scenarios. RESULTS Checklist use resulted in a 6-fold reduction in failure of adherence to critical steps in management for 8 scenarios with 2 pilot teams. These results held in multivariate analysis accounting for clustering within teams and adjusting for learning or fatigue effects (11 of 46 failures without the checklist vs 2 of 46 failures with the checklist; adjusted relative risk = 0.15, 95% CI, 0.04-0.60; p = 0.007). All participants rated the overall quality of the checklists and scenarios to be higher than average or excellent. CONCLUSIONS Checklist use can improve safety and management in operating room crises. These findings warrant broader evaluation, including in clinical settings.


Journal of Neurosurgery | 2007

Use of endovascular coil embolization and surgical clip occlusion for cerebral artery aneurysms

John A. Cowan; John E. Ziewacz; Justin B. Dimick; Gilbert R. Upchurch; B. Gregory Thompson

OBJECT In recent years, endovascular treatment of cerebral artery aneurysms (CAAs) has received greater attention. The authors evaluated patient demographics, endovascular and surgical approaches, and basic outcomes in the treatment of CAAs in a nationally representative administrative database. METHODS Using the Nationwide Inpatient Sample from 1998 to 2003, diagnosed CAA coded as either an unruptured or ruptured lesion and treated with surgical clip occlusion, wrapping combined with endovascular repair, or endovascular repair alone was included in the present study. RESULTS Treatment of CAAs significantly increased for unruptured (from 4036 to 8334 cases, p = 0.002) but not ruptured (from 9330 to 11,269 cases, p = 0.231) lesions. Endovascular treatment of CAAs in particular also increased in patients with unruptured (from 11 to 43%, p < 0.001) and ruptured (from 5 to 31%, p < 0.001) lesions. In 2003, the mortality rate associated with unruptured CAAs treated using clip occlusion (1.36%) or endovascular repair (1.41%) was similar, whereas rate differences were noted between these treatments for ruptured CAAs (12.7% for clip occlusion compared with 16.6% for endovascular repair; p = 0.05). Endovascular treatment of unruptured CAAs was associated with a shorter length of stay (LOS) and higher rate of discharge to home compared with those for clip occlusion. The LOS was also shorter in patients with endovascularly treated ruptured CAAs. Aneurysm type (odds ratio [OR] 10.1, ruptured lesion), patient age (OR 1.28, each 10 years), comorbid conditions (OR 1.08, each condition), and hospital case volume (OR 0.97, each additional case) were significant predictors of death in the regression model. CONCLUSIONS Endovascular techniques for the treatment of CAAs are being used increasingly in the US, although the majority of patients with this pathological entity still undergo surgical clip occlusion. In cases of unruptured CAAs, endovascular treatment is associated with a shorter LOS and higher discharge-to-home rate. Aneurysm status, patient age, comorbid conditions, and hospital case volume are significant predictors of death. Finally, demographic differences exist between the populations presenting with unruptured or ruptured CAAs.


Journal of Neurosurgery | 2015

Comparison of two minimally invasive surgery strategies to treat adult spinal deformity.

Paul Park; Michael Y. Wang; Virginie Lafage; Stacie Nguyen; John E. Ziewacz; David O. Okonkwo; Juan S. Uribe; Robert K. Eastlack; Neel Anand; Raqeeb Haque; Richard G. Fessler; Adam S. Kanter; Vedat Deviren; Frank La Marca; Justin S. Smith; Christopher I. Shaffrey; Gregory M. Mundis; Praveen V. Mummaneni

OBJECT Minimally invasive surgery (MIS) techniques are becoming a more common means of treating adult spinal deformity (ASD). The aim of this study was to compare the hybrid (HYB) surgical approach, involving minimally invasive lateral interbody fusion with open posterior instrumented fusion, to the circumferential MIS (cMIS) approach to treat ASD. METHODS The authors performed a retrospective, multicenter study utilizing data collected in 105 patients with ASD who were treated via MIS techniques. Criteria for inclusion were age older than 45 years, coronal Cobb angle greater than 20°, and a minimum of 1 year of follow-up. Patients were stratified into 2 groups: HYB (n = 62) and cMIS (n = 43). RESULTS The mean age was 60.7 years in the HYB group and 61.0 years in the cMIS group (p = 0.910). A mean of 3.6 interbody fusions were performed in the HYB group compared with a mean of 4.0 interbody fusions in the cMIS group (p = 0.086). Posterior fusion involved a mean of 6.9 levels in the HYB group and a mean of 5.1 levels in the cMIS group (p = 0.003). The mean follow-up was 31.3 months for the HYB group and 38.3 months for the cMIS group. The mean Oswestry Disability Index (ODI) score improved by 30.6 and 25.7, and the mean visual analog scale (VAS) scores for back/leg pain improved by 2.4/2.5 and 3.8/4.2 for the HYB and cMIS groups, respectively. There was no significant difference between groups with regard to ODI or VAS scores. For the HYB group, the lumbar coronal Cobb angle decreased by 13.5°, lumbar lordosis (LL) increased by 8.2°, sagittal vertical axis (SVA) decreased by 2.2 mm, and LL-pelvic incidence (LL-PI) mismatch decreased by 8.6°. For the cMIS group, the lumbar coronal Cobb angle decreased by 10.3°, LL improved by 3.0°, SVA increased by 2.1 mm, and LL-PI decreased by 2.2°. There were no significant differences in these radiographic parameters between groups. The complication rate, however, was higher in the HYB group (55%) than in the cMIS group (33%) (p = 0.024). CONCLUSIONS Both HYB and cMIS approaches resulted in clinical improvement, as evidenced by decreased ODI and VAS pain scores. While there was no significant difference in degree of radiographic correction between groups, the HYB group had greater absolute improvement in degree of lumbar coronal Cobb angle correction, increased LL, decreased SVA, and decreased LL-PI. The complication rate, however, was higher with the HYB approach than with the cMIS approach.


Journal of Neurosurgery | 2013

Validation of the surgical Apgar score in a neurosurgical patient population

John E. Ziewacz; Matthew C. Davis; Darryl Lau; Abd Ulrahman M. El-Sayed; Scott E. Regenbogen; Step Hen E. Sullivan; George A. Mashour

OBJECT The surgical Apgar score (SAS) reliably predicts postoperative death and complications and has been validated in a large cohort of general and vascular surgery patients. However, there has been limited study of the utility of the score in the neurosurgical population. The authors tested the hypothesis that the SAS would predict postoperative complications and length of stay after neurosurgical procedures. METHODS A cohort of 918 intracranial and spine surgery patients treated over a 3-year period were retrospectively evaluated. The 10-point SAS was calculated and postoperative 30-day mortality and complications rates, intensive care unit (ICU) stay, and hospital stay were assessed by 2 independent raters. Univariate analysis and multivariate logistic regression were performed. RESULTS There were 145 patients (15.8%) with at least 1 complication and 24 patients (2.6%) who died within 30 days of surgery. Surgical Apgar scores were significantly associated with the likelihood of postoperative complications (p < 0.001) and death (p = 0.002); scores varied inversely with postoperative complication and mortality risk in a multivariate analysis. Low SASs also predicted prolonged ICU and hospital stay. Patients with scores of 0-2 stayed a mean of 18.9 days (p < 0.001) and patients with scores of 3-4 stayed an average of 14.3 days (p < 0.001) compared with 4.1 days in patients with scores of 9-10. CONCLUSIONS The application of the surgical Apgar score to a neurosurgical cohort predicted 30-day postoperative mortality and complication rates as well as extended ICU and hospital stay. This readily calculated score may help neurosurgical teams efficiently direct postoperative care to those at highest risk of death and complications.


Neurosurgical Focus | 2012

The design, development, and implementation of a checklist for intraoperative neuromonitoring changes.

John E. Ziewacz; Sigurd Berven; Valli P. Mummaneni; Tsung-Hsi Tu; Olaolu C. Akinbo; Russ Lyon; Praveen V. Mummaneni

OBJECT The purpose of this study was to provide an evidence-based algorithm for the design, development, and implementation of a new checklist for the response to an intraoperative neuromonitoring alert during spine surgery. METHODS The aviation and surgical literature was surveyed for evidence of successful checklist design, development, and implementation. The limitations of checklists and the barriers to their implementation were reviewed. Based on this review, an algorithm for neurosurgical checklist creation and implementation was developed. Using this algorithm, a multidisciplinary team surveyed the literature for the best practices for how to respond to an intraoperative neuromonitoring alert. All stakeholders then reviewed the evidence and came to consensus regarding items for inclusion in the checklist. RESULTS A checklist for responding to an intraoperative neuromonitoring alert was devised. It highlights the specific roles of the anesthesiologist, surgeon, and neuromonitoring personnel and encourages communication between teams. It focuses on the items critical for identifying and correcting reversible causes of neuromonitoring alerts. Following initial design, the checklist draft was reviewed and amended with stakeholder input. The checklist was then evaluated in a small-scale trial and revised based on usability and feasibility. CONCLUSIONS The authors have developed an evidence-based algorithm for the design, development, and implementation of checklists in neurosurgery and have used this algorithm to devise a checklist for responding to intraoperative neuromonitoring alerts in spine surgery.


Journal of Neurosurgery | 2014

The effects of smoking on perioperative outcomes and pseudarthrosis following anterior cervical corpectomy: Clinical article.

Darryl Lau; Dean Chou; John E. Ziewacz; Praveen V. Mummaneni

OBJECT Smoking is one of the leading causes of preventable morbidity and death in the U.S. and has been associated with perioperative complications. In this study, the authors examined the effects of smoking on perioperative outcomes and pseudarthrosis rates following anterior cervical corpectomy. METHODS All adult patients from 2006 to 2011 who underwent anterior cervical corpectomy were identified. Patients were categorized into 3 groups: patients who never smoked (nonsmokers), patients who quit for at least 1 year (quitters), and patients who continue to smoke (current smokers). Demographic, medical, and surgical covariates were collected. Multivariate analysis was used to define the relationship between smoking and blood loss, 30-day complications, length of hospital stay, and pseudarthrosis. RESULTS A total of 160 patients were included in the study. Of the 160 patients, 49.4% were nonsmokers, 25.6% were quitters, and 25.0% were current smokers. The overall 30-day complication rate was 20.0%, and pseudarthrosis occurred in 7.6% of patients. Mean blood loss was 368.3 ml and mean length of stay was 6.5 days. Current smoking status was significantly associated with higher complication rates (p < 0.001) and longer lengths of stay (p < 0.001); current smoking status remained an independent risk factor for both outcomes after multivariate logistic regression analysis. The complications that were experienced in current smokers were mostly infections (76.5%), and this proportion was significantly greater than in nonsmokers and quitters (p = 0.013). Current smoking status was also an independent risk factor for pseudarthrosis at 1-year follow-up (p = 0.012). CONCLUSIONS Smoking is independently associated with higher perioperative complications (especially infectious complications), longer lengths of stay, and higher rates of pseudarthrosis in patients undergoing anterior cervical corpectomy.


Neurosurgical Focus | 2013

Intraoperative neuromonitoring with MEPs and prediction of postoperative neurological deficits in patients undergoing surgery for cervical and cervicothoracic myelopathy

Aaron J. Clark; John E. Ziewacz; Michael Safaee; Darryl Lau; Russ Lyon; Dean Chou; Philip Weinstein; Christopher P. Ames; John P. Clark; Praveen V. Mummaneni

OBJECT The use of intraoperative neurophysiological monitoring (IONM) in surgical decompression surgery for myelopathy may assist the surgeon in taking corrective measures to reduce or prevent permanent neurological deficits. We evaluated the efficacy of IONM in cervical and cervicothoracic spondylotic myelopathy (CSM) cases. METHODS The authors retrospectively reviewed 140 cases involving patients who underwent surgery for CSM utilizing IONM during 2011 at the University of California, San Francisco. Data on preoperative clinical variables, intraoperative changes in transcranial motor evoked potentials (MEPs), and postoperative new neurological deficits were collected. Associations between categorical variables were analyzed with the Fisher exact test. RESULTS Of the 140 patients, 16 (11%) had significant intraoperative decreases in MEPs. In 8 of these cases, the MEP signal did not return to baseline values by the end of the operation. There were 8 (6%) postoperative deficits, of which 6 were C-5 palsies and 2 were paraparesis. Six of the patients with postoperative deficits had demonstrated persistent MEP signal change on IONM. There was a significant association between persistent MEP changes and postoperative deficits (p < 0.001). The sensitivity of intraoperative MEP monitoring was 75%, the specificity 98%, the positive predictive value 75%, and the negative predictive value 98%. Due to higher rates of false negatives, the sensitivity decreased to 60% in the subgroup of patients with vascular disease comorbidity. The sensitivity increased to 100% in elderly patients and in patients with preoperative motor deficits. The sensitivity and positive predictive value of deltoid and biceps MEP changes in predicting C-5 palsy were 67% and 67%, respectively. CONCLUSIONS The authors found a correlation between decreased intraoperative MEPs and postoperative new neurological deficits in patients with CSM. Sensitivity varies based on patient comorbidities, age, and preoperative neurological function. Monitoring of MEPs is a useful adjunct for CSM cases, and the authors have developed a checklist to standardize their responses to intraoperative MEP changes.


Neurosurgery Clinics of North America | 2013

The role of minimally invasive techniques in the treatment of adult spinal deformity.

Praveen V. Mummaneni; Tsung-Hsi Tu; John E. Ziewacz; Olaolu C. Akinbo; Vedat Deviren; Gregory M. Mundis

Many surgeons use minimally invasive surgery (MIS) approaches for treatment of patients with adult degenerative spinal deformity. The feasibility and efficacy of these techniques in the treatment of certain subtypes of degenerative deformities have been reported. In this article, several MIS techniques are discussed and an established 6-level treatment algorithm (MiSLAT) is presented, to help guide spinal surgeons in the use of MIS techniques for the treatment of patients with degenerative deformity. MIS treatment of MiSLAT level I to IV deformities is recommended, whereas level V and VI deformities require more traditional open approaches for adequate deformity correction.


Neurosurgical Focus | 2013

Is there a difference in range of motion, neck pain, and outcomes in patients with ossification of posterior longitudinal ligament versus those with cervical spondylosis, treated with plated laminoplasty?

Takahito Fujimori; Hai Le; John E. Ziewacz; Dean Chou; Praveen V. Mummaneni

OBJECT There are little data on the effects of plated, or plate-only, open-door laminoplasty on cervical range of motion (ROM), neck pain, and clinical outcomes. The purpose of this study was to compare ROM after a plated laminoplasty in patients with ossification of posterior longitudinal ligament (OPLL) versus those with cervical spondylotic myelopathy (CSM) and to correlate ROM with postoperative neck pain and neurological outcomes. METHODS The authors retrospectively compared patients with a diagnosis of cervical stenosis due to either OPLL or CSM who had been treated with plated laminoplasty in the period from 2007 to 2012 at the University of California, San Francisco. Clinical outcomes were measured using the modified Japanese Orthopaedic Association (mJOA) scale and neck visual analog scale (VAS). Radiographic outcomes included assessment of changes in the C2-7 Cobb angle at flexion and extension, ROM at C2-7, and ROM of proximal and distal segments adjacent to the plated lamina. RESULTS Sixty patients (40 men and 20 women) with an average age of 63.1 ± 10.9 years were included in the study. Forty-one patients had degenerative CSM and 19 patients had OPLL. The mean follow-up period was 20.9 ± 13.1 months. The mean mJOA score significantly improved in both the CSM and the OPLL groups (12.8 to 14.5, p < 0.01; and 13.2 to 14.2, respectively; p = 0.04). In the CSM group, the mean VAS neck score significantly improved from 4.2 to 2.6 after surgery (p = 0.01), but this improvement did not reach the minimum clinically important difference (MCID). Neither was there significant improvement in the VAS neck score in the OPLL group (3.6 to 3.1, p = 0.17). In the CSM group, ROM at C2-7 significantly decreased from 32.7° before surgery to 24.4° after surgery (p < 0.01). In the OPLL group, ROM at C2-7 significantly decreased from 34.4° to 20.8° (p < 0.01). In the CSM group, the change in the VAS neck score significantly correlated with the change in the flexion angle (r = - 0.31) and the extension angle (r = - 0.37); however, it did not correlate with the change in ROM at C2-7 (r = - 0.1). In the OPLL group, the change in the VAS neck score did not correlate with the change in the flexion angle (r = 0.03), the extension angle (r = - 0.17), or the ROM at C2-7 (r = - 0.28). The OPLL group had a significantly greater loss of ROM after surgery than did the CSM group (p = 0.04). There was no significant correlation between the change in ROM and the mJOA score in either group. CONCLUSIONS Plated laminoplasty in patients with either OPLL or CSM decreases cervical ROM, especially in the extension angle. Among patients who have undergone laminoplasty, those with OPLL lose more ROM than do those with CSM. No correlation was observed between neck pain and ROM in either group. Neither group had a change in neck pain that reached the MCID following laminoplasty. Both groups improved in neurological function and outcomes.

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Darryl Lau

University of California

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Angela M. Bader

Brigham and Women's Hospital

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Atul A. Gawande

Brigham and Women's Hospital

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Paul Park

University of Michigan

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Tsung-Hsi Tu

University of California

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Dean Chou

University of California

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