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Dive into the research topics where Ronald J. Nelson is active.

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Featured researches published by Ronald J. Nelson.


The Annals of Thoracic Surgery | 1990

Tracheal and main bronchial disruptions after blunt chest trauma : presentation and management

Fritz Baumgartner; Barry Sheppard; Christian de Virgilio; Barry Esrig; Dale Harrier; Ronald J. Nelson; John M. Robertson

Tracheobronchial disruption is one of the less common injuries associated with blunt thoracic trauma. This injury can be life threatening, however, and failure to diagnose it early can lead to disastrous acute or delayed complications. Nine cases of tracheobronchial disruption in the setting of nonpenetrating thoracic trauma were seen at four Los Angeles trauma centers between 1980 and 1987. Mechanism of injury, presentation, diagnosis, and management of these patients were reviewed. Disruptions involved the trachea in 3 patients, the right bronchus in 5 patients, and the left bronchus in 2 patients. Tracheobronchial disruptions occurred in settings of high-energy impact-type injuries and were more likely to have associated injuries than they were to occur alone. Common presenting signs included subcutaneous emphysema, dyspnea, sternal tenderness, and hemoptysis. Radiographic findings were most commonly pneumothorax, pneumomediastinum, and clavicle or rib fractures. Rigid bronchoscopy and fiberoptic bronchoscopy were both highly accurate methods for diagnosis but only in the hands of trained cardiothoracic surgeons. Delay in diagnosis increased the likelihood of postoperative complications.


The Annals of Thoracic Surgery | 2000

Annular abscesses in surgical endocarditis: anatomic, clinical, and operative features

Fritz Baumgartner; Bassam Omari; John M. Robertson; Ronald J. Nelson; Avni Pandya; Andy Pandya; Jeffrey C. Milliken

BACKGROUNDnThe aim of this study was to determine patterns of anatomic, clinical, and operative features in surgical endocarditis (SE) with annular abscess (AA).nnnMETHODSnThe study consisted of a retrospective analysis of SE cases with AA between 1981 and 1997.nnnRESULTSnA total of 41 cases with AA were found in 106 consecutive SE cases. There was a higher incidence of AA in aortic (37 of 71 [52%]) (p<0.01) compared to mitral (6 of 42 [14.3%]) or tricuspid (0 of 12) infections. However, the mitral abscesses had a greater tendency toward fistula or pseudoaneurysm formation (4 of 6 [67%]) than other valve abscess cavities (7 of 46 [15%]) (p<0.01). Severe heart failure (p<0.01), heart block (p<0.05), and fistula/pseudoaneurysm (p<0.001), were more often found in SE with AA than without. There were 46 separate aortic AA in 37 instances of aortic valve SE. Of these, 31 of 46 (67%) were less than 1 cm (group 1), 10 of 46 (22%) were large but confined to a given cusp annulus (group 2), 4 of 46 (8.6%) were large between multiple cusps (group 3), and 1 of 46 (2.2%) was circumferential (group 4). There were four instances of aortoventricular discontinuity. Group 1 abscesses were repaired by local closure without a patch significantly more often than the other groups. The mortality of SE with AA was significantly greater for larger AA (groups 3 and 4, 3 of 5 [60%]) than for smaller AA (groups 1 and 2, 0 of 36) (p<0.001). There were six separate mitral AA in six instances of mitral SE, five requiring patch repair. The 30-day operative mortality for AA cases was 3 of 41 (7.3%) compared to 2 of 65 (3.1%) without AA. All AA mortalities involved large AA in the aortic valve position. Of 35 mechanical valves placed for AA, only one required subsequent removal for prosthetic endocarditis.nnnCONCLUSIONSnAnnular abscesses are most frequent in aortic AA, but fistulas/pseudoaneurysms are more frequent in mitral AA. Small to moderate aortic AA can be managed by local closure without an increased mortality compared to SE without AA. Patients with large aortic AA have a higher operative mortality. Mechanical prostheses are safe and effective for the majority of patients with AA.


The Annals of Thoracic Surgery | 1989

Detection of multiple cardiac papillary fibroelastomas using transtsesophageal echocardiography

Christian de Virgilio; Terry J. Dabrow; John M. Robertson; Sharon Siegel; Leonard E. Ginzton; Marianne Nussmeier; Ronald J. Nelson

Papillary fibroelastomas are rare, benign cardiac tumors that may be associated with embolization, angina, and sudden death. We report a case of multiple papillary fibroelastomas diagnosed during life by transesophageal echocardiography. Surgical resection during mitral valve replacement for rheumatic mitral stenosis prevented the development of any of the life-threatening complications sometimes associated with this tumor.


The Annals of Thoracic Surgery | 1990

Ascending aortic dissection in weight lifters with cystic medial degeneration

Christian de Virgilio; Ronald J. Nelson; Jeffrey C. Milliken; Ramon Snyder; F Chiang; William D. MacDonald; John M. Robertson

We report 4 cases of ascending aortic dissection in patients with long histories of weight lifting. In 2 of the patients, the initial symptoms of dissection developed while they were lifting weights. Two patients had a history of hypertension and 2 had previously used anabolic steroids. All 4 were successfully treated surgically. Histopathology showed aortic medial changes in all 4. We believe that the hemodynamic stresses of weight lifting, namely, a rapid increase in systemic arterial blood pressure without a decrease in total peripheral vascular resistance, in combination with aortic medial degeneration may have contributed to the development of the aortic dissection.


Journal of Cardiac Surgery | 1995

Intraoperative angioscopy for coronary bypass surgery.

Sharon B. Siegel; Geoffrey H. White; Philip D. Coiman; Ronald J. Nelson

Despite advances in coronary artery surgery, technical abnormalities remain a significant cause of early graft closure. The development of small fiberoptic angioscopes now allows direct intravascular magnified examination. Seventy‐five distal anastomoses and vein grafts, and five selected coronary arteries were examined with 0.8‐to 2.5‐mm diameter angioscopes introduced through the proximal vein graft while irrigating with clear cardioplegia. Angioscopic findings were correlated with angiographic data, vessel morphology, graft flow, and postoperative course. Satisfactory images were obtained in 72 of 75 anastomotic inspections. Each examination took less than 2 minutes and required less than 100 cc of flush. Angioscopic abnormalities that did not require revision were noted in 17 of 72 anastomoses; intimal flaps in 9, thrombus on posterior wall plaque in 4, intimal irregularities in 4, buckling of posterior wall in 3, and valve near anastomoses in 1. No outflow obstruction nor misplaced sutures were noted. Average flow rate through the grafts with anastomotic angioscopic abnormalities was 33 cc/min versus 40 cc/min in the remaining grafts. However, regression analysis revealed that low‐graft flow was correlated with vessel size and runoff but was not with angioscopic findings. Intracoronary angioscopy revealed discrepancy with angiographic findings in 4 of the 5 examinations. No complications occurred as a result of angioscopy. No graft closure has occurred during early follow‐up. Intraoperative angioscopy can be done with minimal alteration of the usual routine. The 24% occurrence of minor angioscopic abnormalities did not appear to compromise graft flow or early patency.


The Annals of Thoracic Surgery | 1991

Ultrasonic decalcification of the aortic annulus during aortic valve replacement

Barry Sheppard; Jeffrey C. Milliken; Ronald J. Nelson; David M. Follette; John M. Robertson

Aortic valve replacement for calcifica aortic stenosis requires meticulous debridement of the aortic annulus to effect optimal valve seating. Since 1987, we have used ultrasonic energy to debride the aortic annulus during aortic valve replacement in 56 patients. In our experience, ultrasonic debridement of the annulus is superior to traditional methods of debridement, affords improved seating of the valve, and may allow placement of a larger valve. Our follow-up ranges from 2 to 32 months (mean follow-up, 13 +/- 9 months) with 0% incidence of paravalvular leak or valve failure. We advocate the use of ultrasonic debridement as an adjunctive tool in aortic valve replacement.


The Annals of Thoracic Surgery | 1998

Reversible snaring for proper prosthetic seating during valve replacement

Fritz Baumgartner; Bassam Omari; Lillia Stuart; Jeffrey C. Milliken; Ronald J. Nelson; John M. Robertson

A method of reversible suture snaring is described for evaluating the final valve seating and positioning before knot tying of valve sutures. This allows for alteration of the operative plan before investing substantial ischemic time in a nonfunctional result. The procedure has been used in 577 consecutive prosthetic valve replacements in the past 5 years. The technique maintains proper seating while the valve is permanently anchored in place.


Journal of the American College of Cardiology | 1991

Intraoperative angioscopy for coronary bypass surgery

Sharon B. Siegel; Geoffrey H. White; Philip D. Colman; Ronald J. Nelson

Despite advances in coronary artery surgery, technical abnormalities remain a significant cause of early graft closure. The development of small fiberoptic angioscopes now allows direct intravascular magnified examination. Seventy-five distal anastomoses and vein grafts, and five selected coronary arteries were examined with 0.8- to 2.5-mm diameter angioscopes introduced through the proximal vein graft while irrigating with clear cardioplegia. Angioscopic findings were correlated with angiographic data, vessel morphology, graft flow, and postoperative course. Satisfactory images were obtained in 72 of 75 anastomotic inspections. Each examination took less than 2 minutes and required less than 100 cc of flush. Angioscopic abnormalities that did not require revision were noted in 17 of 72 anastomoses; intimal flaps in 9, thrombus on posterior wall plaque in 4, intimal irregularities in 4, bucking of posterior wall in 3, and valve near anastomoses in 1. No outflow obstruction nor misplaced sutures were noted. Average flow rate through the grafts with anastomotic angioscopic abnormalities was 33 cc/min versus 40 cc/min in the remaining grafts. However, regression analysis revealed that low-graft flow was correlated with vessel size and runoff but was not with angioscopic findings. Intracoronary angioscopy revealed discrepancy with angiographic findings in 4 of the 5 examinations. No complications occurred as a result of angioscopy. No graft closure has occurred during early follow-up. Intraoperative angioscopy can be done with minimal alteration of the usual routine. The 24% occurrence of minor angioscopic abnormalities did not appear to compromise graft flow or early patency.


The Annals of Thoracic Surgery | 1989

pleuropulmonary actinomycosis associated with a systemic-to-pulmonary artery fistula and contralateral metastatic back mass

A.Ron Miller; John M. Robertson; Ronald J. Nelson; Carlos A. Castro; Paul S. Dickman

We report a case of systemic-to-pulmonary artery fistula associated with thoracic actinomycosis and with metastatic hematogenous dissemination to the soft tissues of the back. The difficulty in diagnosing thoracic actinomycosis may predispose to the increased incidence of hematogenous spread of this disease. Although resection of pulmonary tissue including the infectious mass was required in previous cases, resection of the pleural mass alone was curative in this patient when combined with penicillin therapy.


Archives of Surgery | 1990

Fibrin Glue Inhibits Intra-abdominal Adhesion Formation

Christian de Virgilio; Terry J. Dubrow; Barry Sheppard; William D. MacDonald; Ronald J. Nelson; Malcolm A. Lesavoy; John M. Robertson

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