Medical Data Research Center

Portland, OR, United States

Medical Data Research Center

Portland, OR, United States
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Wadhwani C.,University of Washington | McAllister B.,Oregon Health And Science University | Wang M.,Medical Data Research Center | Katancik J.A.,Oregon Health And Science University
International Journal of Oral and Maxillofacial Implants | Year: 2017

Assessment of crestal bone levels around implants is essential to monitor success and health. This is best accomplished with intraoral radiographs exposed at 90 degrees to the long axis of the implant, but this can be challenging to achieve clinically. Radiographic paralleling devices produce orthogonal radiographs but traditionally have required access to the implant body for each exposure. This study was conducted to determine if use of the Precision Implant X-ray Locator (PIXRL), a radiographic paralleling device that indexes the implant at the time of surgical placement, can produce orthogonal radiographs of dental implants more accurately than traditional radiologic techniques for assessing crestal bone levels. Materials and Methods: Three dental implants were inserted in dry human skulls in supracrestal positions to simulate crestal bone loss (maxillary right first premolar [site 14], maxillary right central incisor [site 11], and mandibular left second premolar [site 35]). The implants were masked with a soft tissue moulage and restored with provisional restorations. Four dental assistants exposed six radiographs using their usual and customary technique and six using the PIXRL device for each implant. A single examiner measured crestal bone levels on the radiographs relative to the implant platform shoulder on the mesial and distal of each implant. Recorded measurements were compared to the known values. Statistical analysis was completed using a generalized linear regression model to analyze the differences, and post-hoc comparisons with pairwise adjustment were applied. Results: The images produced using the PIXRL device were more accurate overall compared to traditional techniques and were also more consistent. The greater degree of accuracy was statistically significant for all sites with the exception of the mesial measurements of the implant at site 11. Conclusion: This study demonstrates that the use of the PIXRL device can assist clinicians in obtaining more accurate orthogonal radiographs for assessing crestal bone height and would be a useful tool for researchers utilizing radiographic imaging of implants as a longitudinal measure of implant success and stability. © 2017 by Quintessence Publishing Co Inc.


Wang S.,University of Pennsylvania | Kim S.J.,University of Ulsan | Poptani H.,University of Pennsylvania | Woo J.H.,University of Pennsylvania | And 7 more authors.
American Journal of Neuroradiology | Year: 2014

BACKGROUND AND PURPOSE: Differentiation of glioblastomas and solitary brain metastases is an important clinical problem because the treatment strategy can differ significantly. The purpose of this study was to investigate the potential added value of DTI metrics in differentiating glioblastomas from brain metastases. MATERIALS AND METHODS: One hundred twenty-eight patients with glioblastomas and 93 with brain metastases were retrospectively identified. Fractional anisotropy and mean diffusivity values were measured from the enhancing and peritumoral regions of the tumor. Two experienced neuroradiologists independently rated all cases by using conventional MR imaging and DTI. The diagnostic performances of the 2 raters and a DTI-based model were assessed individually and combined. RESULTS: The fractional anisotropy values from the enhancing region of glioblastomas were significantly higher than those of brain metastases (P < .01). There was no difference in mean diffusivity between the 2 tumor types. A classification model based on fractional anisotropy and mean diffusivity from the enhancing regions differentiated glioblastomas from brain metastases with an area under the receiver operating characteristic curve of 0.86, close to those obtained by 2 neuroradiologists using routine clinical images and DTI parameter maps (area under the curve = 0.90 and 0.85). The areas under the curve of the 2 radiologists were further improved to 0.96 and 0.93 by the addition of the DTI classification model. CONCLUSIONS: Classification models based on fractional anisotropy and mean diffusivity from the enhancing regions of the tumor can improve diagnostic performance in differentiating glioblastomas from brain metastases.


Grunkemeier G.L.,Medical Data Research Center | Furnary A.P.,St Vincent Hospital and Medical Center | Wu Y.,Medical Data Research Center | Wang L.,Medical Data Research Center | Starr A.,Oregon Health And Science University
Journal of Thoracic and Cardiovascular Surgery | Year: 2012

Objectives: To compare the probability, and modes, of explantation for Carpentier-Edwards pericardial versus porcine valves. Methods: Our porcine series began in 1974 and our pericardial series in 1991, with annual prospective follow-up. We used the Kaplan-Meier method and Cox regression for estimation and analysis of patient mortality, and the cumulative incidence function and competing risks regression for estimation and analysis of valve durability. Results: Through the end of 2010, we had implanted 506 porcine and 2449 pericardial aortic valves and 181 porcine and 163 pericardial mitral valves. The corresponding total and maximum follow-up years were 3471 and 24, 11,517 and 18, 864 and 22, and 645 and 9. The corresponding probabilities (cumulative incidence function) of any valve explant were 7%, 8%, 22%, and 8%, and of explant for structural valve deterioration were 4%, 5%, 16%, and 5% at 15 years for the first 3 series and at 8 years for the fourth (pericardial mitral valve) series. Using competing risks regression for structural valve deterioration explant, with age, gender, valve size, and concomitant coronary bypass surgery as covariates, a slight (subhazard ratio, 0.79), but nonsignificant, protective effect was found for the pericardial valve in the aortic position and a greater (subhazard ratio, 0.31) and almost significant (P = .08) protective effect of the pericardial valve in the mitral position. Leaflet tear was responsible for 61% of the structural valve deterioration explants in the porcine series and 46% in the pericardial series. Conclusions: Using competing risks regression, the pericardial valve had a subhazard ratio for structural valve deterioration explant of less than 1 in both positions, approaching statistical significance in the mitral position. The mode of structural valve deterioration was predominantly leaflet tear for porcine valves and fibrosis/calcification for pericardial valves. Copyright © 2012 by The American Association for Thoracic Surgery.


Soot L.,Providence Cancer Center | Weerasinghe R.,Providence Cancer Center | Wang L.,Medical Data Research Center | Nelson H.D.,Providence Cancer Center | Nelson H.D.,Oregon Health And Science University
American Journal of Surgery | Year: 2014

Background High rates of surgical breast biopsies in community hospitals have been reported but may misrepresent actual practice. Methods Patient-level data from 5,757 women who underwent breast biopsies in a large integrated health system were evaluated to determine biopsy types, rates, indications, and diagnoses. Results Between 2008 and 2010, 6,047 breast biopsies were performed on 5,757 women. Surgical biopsy was the initial diagnostic procedure in 16% (n = 942) of women overall and in 6% (72 of 1,236) of women with newly diagnosed invasive breast cancer. Invasive breast cancer was diagnosed in 72 women (8%) undergoing surgical biopsy compared with 1,164 (24%) undergoing core needle biopsy (P <.001, age adjusted). Main indications for surgical biopsies included symptomatic abnormalities, technical challenges, and patient choice. Conclusions Surgical biopsy was the initial diagnostic procedure in 16% of women with breast abnormalities, comparable with rates at academic centers. Rates could be improved by more careful consideration of indications. © 2014 Elsevier Inc. All rights reserved.


Handy Jr. J.R.,Providence Cancer Center | Asaph J.W.,Earle A Chiles Research Institute | Douville E.C.,Thoracic and CardioVascular Surgery | Ott G.Y.,Thoracic and CardioVascular Surgery | And 2 more authors.
European Journal of Cardio-thoracic Surgery | Year: 2010

Objective: We evaluated video-assisted thoracic surgery (VATS) and open (OPEN) lobectomy for lung cancer and impact upon 6-month postoperative (postop) functional health status and quality of life. Methods: In this retrospective analysis of prospective, observational data, anatomic lobectomy with staging thoracic lymphadenectomy was performed with curative intent for lung cancer. OPEN consisted of either thoracotomy (TH) or median sternotomy (MS). Technique was selected on the basis of anatomic imperative (OPEN: larger or central; VATS smaller or peripheral tumours) and/or surgical skills (VATS lobectomy initiated in 2001). All patients completed the Short Form 36 Health Survey (SF36) and Ferrans and Powers quality-of-life index (QLI) preoperatively (preop) and 6 months postop. Results: A total of 241 patients underwent lobectomy (OPEN, 192; VATS, 49). OPEN included MS 128 and TH 64. Comparison of MS and TH patient demographics, co-morbidities, pulmonary variables, intra-operative variables, stage and cell type, postop complications and 6-month clinical outcomes found no differences, allowing grouping together into OPEN. The VATS group had better pulmonary function testing (PFT), more adenocarcinoma and lower stage. The VATS and OPEN groups did not differ regarding operating time, postop complications and operative or 6-month mortality. The VATS group had less blood loss, transfusion, intra-operative fluid administration and shorter length of stay. Comparing within each group's preop to 6-month postop data, VATS patients were either the same or better in all SF36 categories (physical functioning, role functioning - physical, role functioning - emotional, social functioning, bodily pain, mental health, energy and general health). The OPEN group, however, was significantly worse in SF36 categories physical functioning, role functioning - physical and social functioning. The preop and 6 months postop VATS versus OPEN QLI scores were not different. At 6 months postop, hospital re-admission and use of pain medication was less in the VATS group. In addition, the VATS group had better preservation of preop performance status. Conclusions: VATS lobectomy for curative lung cancer resection appears to provide a superior functional health recovery compared with OPEN techniques. © 2009 European Association for Cardio-Thoracic Surgery.


Kurian A.A.,Providence Cancer Center | Wang L.,Medical Data Research Center | Grunkemeier G.,Medical Data Research Center | Bhayani N.H.,Providence Cancer Center | Swanstrom L.L.,Oregon Clinic GMIS Division
Annals of Surgery | Year: 2013

Objective: "The elderly" is an often used but poorly defined descriptor of surgical patients. Investigators have used varying subjectively determined age cutoffs to report outcomes in the elderly.We set out to use objective outcomes data to determine the "at-risk" elderly population. Methods: • Patients: 129,331 patients identified from the ACS-NSQIP database (2005- 2010) undergoing major gastrointestinal resections. • Outcome: Mortality. • Statistical methods: Locally weighted regression was used to fit the trend line of mortality over age. Receiver operating characteristic analysis was used to identify the "predictive age" for mortality. Results: Mortality steadily increases with age. On receiver operating characteristic analysis, there is a nonlinear transition zone (50-75 years of age) flanked by 2 linear zones on either end. The younger linear zone showed a low mortality increase (0.5% per decade). Larger mortality increase with age (5.3% per decade) was observed at the older age end. Similar patterns were observed for large-volume surgical subtypes, with clustering of a "critical age" beyond which mortality increases dramatically at 75 ±2 years. Receiver operating characteristic analysis identified the "optimum age" for mortality being 68.5 years (area under the curve = 0.72, sensitivity = 66.6%, and specificity = 65.5%). Conclusions: Mortality risk for major gastrointestinal surgical resections starts increasing at 50 years of age, and at 75 years of age, it starts increasing very rapidly. The optimum age of 68.5 years predicts mortality with the best combination of sensitivity and specificity. These ages should be used to standardize outcome data and focus perioperative resources to improve outcomes. © 2013 Lippincott Williams & Wilkins.


Jin R.,Medical Data Research Center | Furnary A.P.,Medical Data Research Center | Fine S.C.,Medical Data Research Center | Blackstone E.H.,Cleveland Clinic | Grunkemeier G.L.,Medical Data Research Center
Annals of Thoracic Surgery | Year: 2010

The Society of Thoracic Surgeons National Adult Cardiac Surgery Database (STS NCD) has become the national benchmark for cardiac surgery reporting. Several important aspects of its risk-adjustment reporting are discussed, with special emphasis on using the reported individual STS risk scores for analysis and evaluation: (1) Different risk models are used in different STS NCD versions. (2) STS calibrates risk scores annually to make the annual predicted rates equal the observed rates. (3) The risk scores given by the STS, whether in the approved STS data collection software programs, published risk models, or online calculator, are not calibrated. (4) The end-user is required to calibrate the STS risk scores before using them. (5) After calibration, the STS predicted risk for any given patient is usually smaller, sometimes less than half of the uncalibrated value. (6) STS uses an observed/expected ratio method to calibrate the risk scores; for technical reasons, it is preferable to use an odds ratio method. © 2010 The Society of Thoracic Surgeons.


Jin R.,Medical Data Research Center | Grunkemeier G.L.,Medical Data Research Center
Annals of Thoracic Surgery | Year: 2013

Background: New York (NY) valve and valve/coronary artery bypass grafting (CABG) mortality risk models, developed from operations performed in 2007 to 2009, have just been published. These models were validated using NY data from 2004 to 2006. The authors stated that their models "should also be validated by testing them against non-New York populations." Thus, we validated the NY models with the Providence Health & Services-Swedish Health Services (PH&S-SHS) cardiac surgical data and also compared them with The Society of Thoracic Surgeons (STS) mortality risk models. Methods: The PH&S-SHS validation data set contained 4,021 isolated valve and 2,406 valve/CABG operations, performed from 2008 to 2012. The risk models (NY logistic and score models and the STS models) were recalibrated to equalize the expected and observed number of deaths. Discrimination was tested by C statistics and calibration by Hosmer-Lemeshow statistics. Results: PH&S-SHS operative mortality rates were 2.6% and 5.5% in the valve and valve/CABG operations, respectively, and were lower than the NY rates. The C statistics for the NY logistic valve and valve/CABG models were 0.777 and 0.727, respectively, and were very similar for the NY score models. Calibration was good for the NY valve model (p = 0.85), but not for the NY valve/CABG model (p = 0.01). The STS models had better discrimination than NY models and good calibration. Conclusions: The NY logistic and score models for valve operations fit the PH&S-SHS data well with acceptable discrimination and good calibration. The NY models for valve/CABG operations fit the PH&S-SHS data with acceptable discrimination and poor calibration. STS logistic regression models fit the PH&S-SHS data somewhat better. © 2013 The Society of Thoracic Surgeons.


Duwelius P.J.,11782 SW Barnes Road and 300 | Burkhart B.,11782 SW Barnes Road and 300 | Carnahan C.,11782 SW Barnes Road and 300 | Branam G.,Orthopedic Institute | And 5 more authors.
Clinical Orthopaedics and Related Research | Year: 2014

Background: Restoration of the hip center is considered important for a successful THA and requires achieving the right combination of offset, anteversion, and limb length. Modular femoral neck designs were introduced to make achieving this combination easier. No previous studies have compared these designs in primary THA, and there is increasing concern that modular designs may have a higher complication rate than their nonmodular counterparts. Questions/purposes: We therefore asked (1) whether use of a stem with a modular neck would restore limb length and offset more accurately than a stem with a nonmodular neck, and (2) whether patients who received modular neck systems had better hip scores or a lower frequency of complications and reoperations than those receiving a comparable nonmodular stem. Methods: Two cohorts of patients undergoing primary THAs, 284 patients with a nonmodular neck and 594 patients with a modular neck, were treated by one surgeon through a posterior approach. These were two nearly sequential series with little overlap. Harris hip scores and SF-12 outcomes surveys were administered at followup with a mean of 2.4 years (maximum, 5.9 years). Results: In the modular neck cohort, a greater proportion of patients had equal (within 5 mm) radiographic limb lengths (89%, compared with 77% in nonmodular cohort p = 0.036), and a smaller offset difference (6.1 versus 7.5 mm, p = 0.047) was observed. Whether these statistical differences are clinically important is unclear. A smaller proportion of patients in the modular neck cohort achieved equal apparent or clinical limb length at 1 year (85% versus 95%, p < 0.001) and at 2 years (81% versus 94%, p < 0.001). In addition, these differences did not appear to result in better Harris hip or SF-12 scores, fewer complications, or reduced likelihood of revision surgery. Conclusions: Use of modular neck stems did not improve hip scores nor reduce the likelihood of complications or reoperations. Because of their reported higher risks, there is no clear indication for modularity with a primary THA, unless the hip center cannot be achieved with a nonmodular stem, which is rare. Level of Evidence: Level III, therapeutic study. See the Instructions to Authors for a complete description of levels of evidence. © 2013 The Association of Bone and Joint Surgeons®.


Duwelius P.J.,Providence St Vincent Hospital And Medical Center | Moller H.S.,Providence St Vincent Hospital And Medical Center | Burkhart R.L.,Providence St Vincent Hospital And Medical Center | Waller F.,St Vincent Hospital And Medical Center | And 2 more authors.
Journal of Arthroplasty | Year: 2011

We compared hospital length of stay (LOS) and costs between (1) minimally invasive total hip surgery (MIS) combined with an active hip pathway (AHP) and (2) long incision total hip surgery (LIS) with a passive hip pathway (PHP). A prospective consecutive cohort of 214 MIS/AHP patients was compared to a concurrent cohort of 265 LIS/PHP patients. The MIS/AHP cohort had significantly decreased LOS (1.5 days vs. 3.8 days, P < .001) and hospital costs ($12.8 thousand vs. $16.7 thousand, P < .001). The complication rates were similar for MIS/AHP and LIS/PHP. We conclude that, compared to LIS/PHP, MIS/AHP significantly shortened LOS by an average of 2.3 days, and significantly reduced hospital costs by an average of $3.9 thousand per patient. © 2011 Elsevier Inc..

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