Biomedical subjects

Samuel E Wilson

Publications and source records attributed to Samuel E Wilson.

51 records · Page 3Linked to original sources

PubMed2003

Postoperative complications of carotid patching: pseudoaneurysm and infection.

Patch angioplasty after carotid endarterectomy has been advocated to improve results by decreasing the incidence of recurrent stenosis and postoperative carotid thrombosis. Aneurysmal and infectious complications may be secondary to use of prosthetic materials in arterial reconstruction. We report four patients who developed late operative site complications related to carotid patching. All four of our patients had delayed pseudoaneurysms and three had infection related to the Dacron patch. In a typical case, a 57-year-old who had a right carotid endarterectomy in 1994 presented with a 1-month history of an enlarging right neck mass 7 years later. Imaging revealed a 6 x 4 cm pseudoaneurysm originating from an opening between the patch graft and the old endarterectomized carotid wall. Analysis of the literature disclosed an additional 45 patients who had pseudoaneurysms and/or infection related to carotid patching, most frequently with Dacron. We postulate that a low-grade Staphylococcus epidermidis infection of the foreign body patch may be the etiology. Autogenous saphenous vein interposition graft and antimicrobials effective against gram-positive organisms corrected the pseudoaneurysm. Although the benefits of routine carotid patching may include a decrease in restenosis, this advantage must be weighed against the risk of late pseudoaneurysm and/or infection when a prosthetic patch is used to closed the endarterectomy site.

Aged↗

PubMed2003

Complications after laparoscopic gastric bypass: a review of 3464 cases.

HYPOTHESIS: The type and frequency of complications after open Roux-en-Y gastric bypass (GBP) have changed with the development of laparoscopic technique. BACKGROUND: The number of laparoscopic GBP cases performed in the United States has increased dramatically during the past several years. We compared the type and frequency of complications after laparoscopic and open GBP. METHODS: We searched MEDLINE from January 1, 1994, through December 31, 2002, using the keywords morbid obesity, laparoscopy, bariatric surgery, and gastric bypass. We selected studies on laparoscopic or open GBP with more than 50 patients and published in the English language for analysis. We excluded studies with reoperative Roux-en-Y GBP cases or other bariatric procedures. The type and frequency of postoperative complications were recorded from each study. We used chi2 and Fisher exact tests to determine statistical significance. RESULTS: Ten laparoscopic GBP studies with 3464 patients and 8 open GBP studies with 2771 patients were considered. The mean of the reported average age for patients undergoing laparoscopic GBP was 41 years compared with 43 years for open GBP. The mean percentages of female patients were 87% for laparoscopic GBP and 82% for open GBP; the mean reported average body mass index (calculated as weight in kilograms divided by the square of height in meters), 48.7 and 49.5, respectively. Compared with open GBP, laparoscopic GBP was associated with a decrease in the frequency of iatrogenic splenectomy, wound infection, incisional hernia, and mortality; however, there was an increase in the frequency of early and late bowel obstruction, gastrointestinal tract hemorrhage, and stomal stenosis. There were no significant differences in the frequency of anastomotic leak, pulmonary embolism, or pneumonia. CONCLUSIONS: The type and frequency of postoperative complications after laparoscopic and open GBP are different. Certain complications increase with laparoscopic GBP, probably owing to the learning curve of this complex procedure, whereas other complications decrease because of the advantages of the smaller access incision.

Adult↗

PubMed2003

Quality of life, impotence, and activity level in a randomized trial of immediate repair versus surveillance of small abdominal aortic aneurysm.

OBJECTIVE: We compared long-term health-related quality-of-life outcome after randomization to immediate elective repair or imaging surveillance, and in relation to time of elective repair, in patients with small asymptomatic abdominal aortic aneurysm (AAA). METHODS: This randomized clinical trial was carried out in 16 Veterans Affairs medical centers. Study subjects were patients at good surgical risk, aged 50 to 79 years, with AAAs 4.0 to 5.4 cm in diameter. Interventions included immediate open surgical AAA repair or imaging surveillance every 6 months with repair reserved for AAAs that became symptomatic or enlarged to 5.5 cm. Main outcome measures considered were SF-36 health status questionnaire, prevalence of impotence, and maximum activity level, which were determined at randomization and at all follow-up visits. RESULTS: Eleven hundred thirty-six patients were randomized and followed up for 3.5 to 8 years (mean, 4.9 years). The two randomized groups did not differ significantly for most SF-36 scales at most times, but the immediate repair group scored higher overall in general health (P <.0001), which was particularly evident in the first 2 years after randomization, and slightly lower in vitality (P <.05). The baseline value of one SF-36 scale, physical functioning, was an independent predictor of mortality. Overall, more patients became impotent after randomization to immediate repair compared with surveillance (P <.03), but this difference did not become apparent until more than 1 year after randomization. Maximum activity level did not differ significantly between the two randomized groups, but decline over time was significantly greater in the immediate repair group (P <.02). CONCLUSIONS: For most quality-of-life measures and times there was no difference between randomized groups. Immediate repair resulted in a higher prevalence of impotence more than 1 year after randomization, but was also associated with improved perception of general health in the first 2 years.

Aged↗

PubMed2003

Serial abdominal closure technique (the "SAC" procedure): a novel method for delayed closure of the abdominal wall.

Abdominal compartment syndrome may occur after any elective or emergent abdominal operations that are complicated by postoperative hemorrhage or in the trauma patient who has massive fluid replacement for intra-abdominal bleeding. Once the abdomen is decompressed the type of closure varies as much as the surgeon performing the procedure. We have devised a simple, reproducible, inexpensive, and safe method to close the abdomen at the bedside. Serial abdominal closure (SAC) was performed on three patients 45, 54, and 14 years of age who had developed abdominal compartment syndrome secondary to an upper gastrointestinal bleed requiring massive transfusion, a tear of the superior mesenteric vein, and a grade 4 liver laceration respectively, all necessitating abdominal decompression. All three patients had their abdominal wounds closed at the bedside over the course of several days with our SAC technique. Subsequent postoperative course was uneventful and the abdominal wall was free of defects at one-year follow-up. SAC is an efficient, inexpensive, and easily reproducible method of managing the open abdomen. The use of SAC prevented abdominal closure-related complications such as enteric fistula and hernia formation in our three patients.

Abdomen↗

PubMed2003

Computed tomography angiography validates duplex sonographic evaluation of carotid artery stenosis.

Controversy regarding the optimal preoperative evaluation for patients with carotid arterial stenosis remains controversial. We hypothesized that carotid artery area reduction measured by computed tomography angiography (CTA) would closely correlate with duplex scanning stenosis. This study was undertaken to evaluate the correlation between duplex, CTA, and conventional arteriography in patients undergoing consideration for carotid endarterectomy. Patients undergoing evaluation for carotid artery stenosis who received at least 2 of the diagnostic tests were included in this study (n = 108); 30 patients underwent all 3 imaging modalities. Linear regression analysis was performed to determine correlation coefficients between the 3 different study modalities. Correlation and P values were as follows: CTA area versus CTA diameter, r = 0.82, P < 0.001; CTA area versus duplex stenosis, r = 0.71, P < 0.001; duplex stenosis versus angio diameter, r = 0.68; P = 0.005; CTA diameter versus angio diameter, r = 0.61, P = 005. CTA was able to identify plaque characteristics more readily than duplex or arteriography. CTA was also able to differentiate critical stenosis from occlusion and to settle discrepancies obtained from duplex scanning. CTA is an acceptable alternative method to validate duplex scanning evaluation of carotid artery stenosis. It can accurately measure lumen stenosis, visualize plaque morphology, and is associated with fewer complications than conventional angiography.

Aged↗

PubMed2002

Rupture rate of large abdominal aortic aneurysms in patients refusing or unfit for elective repair.

CONTEXT: Among patients with abdominal aortic aneurysm (AAA) who have high operative risk, repair is usually deferred until the AAA reaches a diameter at which rupture risk is thought to outweigh operative risk, but few data exist on rupture risk of large AAA. OBJECTIVE: To determine the incidence of rupture in patients with large AAA. DESIGN AND SETTING: Prospective cohort study in 47 Veterans Affairs medical centers. PATIENTS: Veterans (n = 198) with AAA of at least 5.5 cm for whom elective AAA repair was not planned because of medical contraindication or patient refusal. Patients were enrolled between April 1995 and April 2000 and followed up through July 2000 (mean, 1.52 years). MAIN OUTCOME MEASURE: Incidence of AAA rupture by strata of initial and attained diameter. RESULTS: Outcome ascertainment was complete for all patients. There were 112 deaths (57%) and the autopsy rate was 46%. Forty-five patients had probable AAA rupture. The 1-year incidence of probable rupture by initial AAA diameter was 9.4% for AAA of 5.5 to 5.9 cm, 10.2% for AAA of 6.0 to 6.9 cm (19.1% for the subgroup of 6.5-6.9 cm), and 32.5% for AAA of 7.0 cm or more. Much of the increased risk of rupture associated with initial AAA diameters of 6.5-7.9 cm was related to the likelihood that the AAA diameter would reach 8.0 cm during follow-up, after which 25.7% ruptured within 6 months. CONCLUSION: The rupture rate is substantial in high-operative-risk patients with AAA of at least 5.5 cm in diameter and increases with larger diameter.

Aged↗

PubMed2002

Intra-abdominal Sepsis in Elderly Persons.

Elderly patients represent a greater percentage of the population now than ever before, with 12.4% of North Americans being >65 years of age. Intra-abdominal illnesses in this population often have different etiologies than those seen in younger populations. Because of a variety of physiologic changes that occur as people age, elderly persons have different sites of infection, may present with vague symptoms and longer histories, are more gravely ill, and, overall, have worse prognoses. The major causes of intra-abdominal sepsis in elderly persons are reviewed, explanations for the differences in presentation and prognosis are offered, and the treatments of each cause are reviewed.

Abdominal Abscess↗

PubMed2002

Immediate repair compared with surveillance of small abdominal aortic aneurysms.

BACKGROUND: Whether elective surgical repair of small abdominal aortic aneurysms improves survival remains controversial. METHODS: We randomly assigned patients 50 to 79 years old with abdominal aortic aneurysms of 4.0 to 5.4 cm in diameter who did not have high surgical risk to undergo immediate open surgical repair of the aneurysm or to undergo surveillance by means of ultrasonography or computed tomography every six months with repair reserved for aneurysms that became symptomatic or enlarged to 5.5 cm. Follow-up ranged from 3.5 to 8.0 years (mean, 4.9). RESULTS: A total of 569 patients were randomly assigned to immediate repair and 567 to surveillance. By the end of the study, aneurysm repair had been performed in 92.6 percent of the patients in the immediate-repair group and 61.6 percent of those in the surveillance group. The rate of death from any cause, the primary outcome, was not significantly different in the two groups (relative risk in the immediate-repair group as compared with the surveillance group, 1.21; 95 percent confidence interval, 0.95 to 1.54). Trends in survival did not favor immediate repair in any of the prespecified subgroups defined by age or diameter of aneurysm at entry. These findings were obtained despite a low total operative mortality of 2.7 percent in the immediate-repair group. There was also no reduction in the rate of death related to abdominal aortic aneurysm in the immediate-repair group (3.0 percent) as compared with the surveillance group (2.6 percent). Eleven patients in the surveillance group had rupture of abdominal aortic aneurysms (0.6 percent per year), resulting in seven deaths. The rate of hospitalization related to abdominal aortic aneurysm was 39 percent lower in the surveillance group. CONCLUSIONS: Survival is not improved by elective repair of abdominal aortic aneurysms smaller than 5.5 cm, even when operative mortality is low.

Aged↗

PubMed2002

Determinants for successful percutaneous image-guided drainage of intra-abdominal abscess.

HYPOTHESIS: Characteristics of intra-abdominal abscess can be used to predict successful outcome for percutaneous catheter drainage (PCD). METHODS: We performed a multicenter prospective study of patients who had intra-abdominal infections treated with PCD and intravenous antibiotics. Multivariate regression analysis determined predictors of successful outcome. RESULTS: The study included 96 patients (59% men; mean +/- SD age, 48 +/- 17 years; mean +/- SD Acute Physiology and Chronic Health Evaluation II score, 7.4 +/- 4.9). Postoperative abscess was present in 53% of patients. Isolated microorganisms included Bacteroides species (17%), Escherichia coli (17%), Streptococcus species (14%), Enterococcus species (10%), and fungi (11%). Single abscesses were present in 83% of patients. Computed tomographic guidance was used for drainage in 80% of patients, and ultrasound was used in 20%. The duration of abscess drainage was less than 14 days in 64%. Complete resolution of the infection with a single treatment of PCD was achieved in 67 patients (70%), and with a second attempt in 12 (12%). Thirty-three patients (34%) had PCD for the resolution of intra-abdominal sepsis prior to an elective, definitive procedure. Open drainage as a result of PCD failure was required in 15 (16%) and was more likely in patients with yeast (P<.001) or a pancreatic process (P =.02). Postoperative abscess (P =.04) was an independent predictor of successful outcome. CONCLUSIONS: Percutaneous catheter drainage of intra-abdominal infections was effective with a single treatment in 70% of patients and increased to 82% with a second attempt. A successful outcome is most likely with abscesses that are postoperative, not pancreatic, and not infected with yeast. Percutaneous catheter drainage is now a commonly used staging method for the resolution of intra-abdominal sepsis prior to corrective operation.

Abdominal Abscess↗

PubMed2002

Choosing general surgery: insights into career choices of current medical students.

HYPOTHESIS: The number of unfilled general surgery programs in the United States increased from 4 in 1999 to 41 in 2001. This study seeks to determine if changes in student attitudes occurring during their medical school careers and during the third-year general surgery clerkship contribute to a decline in interest in a surgical career. DESIGN: Prospective survey of medical students at a public medical school in California. PARTICIPANTS AND METHODS: Each medical student received a survey via the Internet. Responses were anonymous. Once quantified, chi(2) analysis was used for comparison and analysis of survey results. Comparisons were made between individual class years and on the basis of whether the respondent completed the third-year general surgery clerkship. RESULTS: Of 368 surveys sent, 232 (63%) were successfully completed and included in the study. Comparison of students' attitudes before and after completion of their general surgery clerkship showed that following surgical course exposure more students believed surgery lacked breadth of expertise, limitations over stress, control over one's time, regularity of schedule, adequacy of leisure time, and income commensurate to workload (P<.05). These results are also consistent in comparisons between individual class years. CONCLUSIONS: Data suggest that medical students seem to be more concerned with issues of "controllable lifestyle" such as adequacy of family and/or leisure time, high level of stress, and amount of work and commitment. The erosion of income differential between demanding and less taxing specialties was also an important cause cited for the flagging interest in surgical disciplines.

Adult↗

PubMed2002

Middle aortic syndrome: distal thoracic and abdominal coarctation, a disorder with multiple etiologies.

BACKGROUND: Congenital coarctation of the thoracic aorta at the ligamentum arteriosum or the aortic arch is well recognized. But a much less common variety (0.5% to 2.0%) of aortic coarctation is located in the distal thoracic aorta, or abdominal aorta, or both and is often called "middle aortic syndrome" or "mid-aortic dysplastic syndrome." These types of aortic coarctation are most often secondary to a form of granulomatis vasculitis commonly known as Takayasu's disease in this country or aortitis syndrome in Japan. No single genesis explains every case and beside vasculitis as a cause, some are thought to be congenital in origin and others are associated with von Recklinghausen's disease. STUDY DESIGN: Eight patients with severe hypertension or claudication secondary to middle aortic coarctation were studied with aortograms and subsequently treated by vascular reconstruction procedures. RESULTS: Vascular reconstructions consisted of aortoaortic bypass, aortic resection with interposed grafting, reanastomotic resection of renal arteries into prosthetic grafts, and renal artery bypass with autogenous material. All eight patients' grafts have remained patent, with followups of 4 to 9 years, with relief of hypertension and claudication. Although Takayasu's disease can be progressive, aggressive surgical treatment in eight patients followed for 4 to 8 years postoperatively demonstrates that severe hypertension, claudication, or both are important indications for revascularization. CONCLUSIONS: Whatever the cause, assuming that active aortic inflammation has been medically treated and is in a burned-out state, patients with abdominal coarctation who have symptomatic renovascular hypertension, claudication, or both are good candidates for revascularization. Although surgical repair is more difficult than with congenital thoracic coarctation, because aortic walls are fibrotic and often also involve the renals, all eight of our patients had successful longterm correction of their hypertension and coarctation.

Adolescent↗

PubMedDate not supplied

Reducing the noneducational and nonclinical workload of the surgical resident; defining the role of the health technician.

PURPOSE: Recent controversy over excessive resident work hours has prompted surgical educators and program directors to search for more efficient methods to limit the nonclinical and noneducational workload of surgical residents. Health technicians were employed at a large Veteran's Administration Medical Center to allow residents more time for direct patient care in the clinics and wards and in educational activities. METHODS: In a two-week period, daily data cards were collected from each intern and health technician identifying total hours spent in work, operations, clinics, and conferences. Each intern recorded the number and type of tasks performed and those tasks assigned to the health technician. The number and type of task performed were tabulated and averaged for each health technician and physician. RESULTS: Each intern (n = 3) and health technician (n = 8) completed 100% of the required data forms. In a control survey, each intern worked a mean of 16.9 hours per weekday and 5.0 hours per weekend day. With the addition of the health technicians, interns worked 12.9 hours per weekday and 6.8 hours per weekend day (when the health technicians were not present). Following the addition of the health technicians, resident time in the operating room increased from 3.3 hours per week to 9.8 hours per week. Each health technician aided the intern by performing an average of 20.25 tasks per day. CONCLUSIONS: This study shows that health technicians can be effective in reducing the overall hours and workload of surgical residents and increasing time spent in the operating room. Consideration should be given to including the health technician as integral members of the health care team in the teaching hospital.

Allied Health Personnel↗

PubMedDate not supplied

Comparison of CT and catheter arteriography for evaluation of peripheral arterial disease.

Computed tomographic arteriography (CTA) has emerged as a promising technique for less invasive imaging of the lower extremity arteries. The aim of this study was to determine the concordance between CTA and catheter arteriography (CA) in patients with peripheral arterial disease (PAD). Twenty-five patients underwent both CTA and CA, and each set of images was interpreted independently by 3 readers. The infrarenal arteries were divided into 16 segments, and each segment was scored as: 1 = stenosis <50%; 2 = 50-99% stenosis; 3 = occlusion. Modal scores from 3 readers were used to compare results for each segment, with CA assumed to represent true arterial anatomy. Agreement between CTA and CA readings was defined as: concordance (modal scores were identical); moderate discrepancy (MD) (modal scores differed by 1); or severe discrepancy (SD) (modal scores differed by 2). In total, 718 segments were assessed by both CTA and CA. For all segments, the sensitivity and specificity of CTA for <50% stenosis was 86% and 90%; for 50-99% stenosis, sensitivity and specificity were 79% and 89%; and for occlusion, 85% and 98%. Above-knee (AK) CTA scores had slightly better concordance of 86.1% than below-knee (BK) readings (82.3%) (p = 0.104). Severe discrepancies between AK CTA and CA scores were observed in 1.8% of segments compared to 5.4% of BK segments (p = 0.038). Poor CTA image quality was the cause in 20% of AK segments and 28% of BK segments. Poor CA image quality was the cause in 8% of AK and 7% of BK discrepancies. Registration disagreement (stenosis observed in a level in 1 study attributed to a different level in the other) accounted for 18% of AK and 17% of BK discrepancies. In 54% of AK and 48% of BK discrepancies, neither image quality nor registration errors were identified, indicating that inherent differences in the depiction of stenosis by CA and CTA were responsible. When discrepancies caused by registration error were excluded, SD observed in BK segments (4.0%) remained significantly higher than in AK segments (1.25%) (p = 0.029), and poor CTA quality image was the most common cause (76%) of severe BK discrepancies. In AK discrepancies without an identifiable technical cause, CTA uniformly showed more stenosis, suggesting greater CTA diagnostic precision in larger vessels. In general, agreement between CTA and CA was moderately good. Compared to CA, CTA may be better at depicting stenosis in large, proximal vessels owing to the superior accuracy of cross-sectional images in the measurement of stenosis. There appeared to be poorer CT resolution and higher frequency of severe discrepancies between CTA and CA in BK arteries.

Age Factors↗

PubMedDate not supplied

Resistance within hemodialysis shunts predicts patency.

The authors examined the relationship between patency after thrombectomy of clotted dialysis grafts and intraoperative measurements of flow (Q), pressure gradient (PGR), and longitudinal resistance (RL). Eighteen thrombosed arteriovenous (AV) grafts underwent 21 thrombectomies. Pressures at arterial (P1) and venous (P2) ends of the AV grafts were determined with 22-gauge catheters and standard transducers; flow was measured with transit-time probes; arithmetic averaging of waveforms was used to compute mean Q, PGR, and RL. Kaplan-Meier patency curves were analyzed by using log rank methods. Mean patency for all grafts was 164 +/-152 days. For each variable, the 21 measurements were split and the patency curve for the grafts with the 11 lowest value grafts was compared to the curve representing the 10 highest value grafts. The difference between high RL versus low RL patency curves was significant with high-resistance grafts having a median patency of 55 days and low-resistance grafts having a median patency greater than 151 days (p = 0.0089). In contrast, the high Q group median patency was 151 days versus 174 days for the low Q group (p = 0.86). Median patency for the low PGR group was 115 days compared to 62 days for the high PGR group (p = 0.162). Longitudinal resistance within AV grafts, but not flow or pressure gradient, showed a significant correlation with patency after thrombectomy. Increased resistance to flow within AV grafts appears to be an important factor affecting the propensity of dialysis grafts to thrombose.

Arteries↗

PubMedDate not supplied

Gastrointestinal hemorrhage after laparoscopic gastric bypass.

Gastrointestinal hemorrhage is a potential perioperative complication after Roux-en-Y gastric bypass. The surgeon performing laparoscopic gastric bypass should understand the need for early recognition and management of this complication, as it can be life-threatening. This paper discusses the incidence and clinical presentation of gastrointestinal hemorrhage, mechanisms for hemorrhage, management options, and possible methods of prevention.

Adult↗