William E. Anderson

Cellular ingrowth and thickness changes in poly-L-lactide and polyglycolide matrices implanted subcutaneously in the rat.

Highly porous matrices of poly-L-lactide (PL) and polyglycolide (PG), 24, 50, or 95 mg/cc in the form of 10 x 10 x 3 mm wafers, were implanted subcutaneously (two per rat) in the flanks of 8-12-week-old female Lewis rats (n = 120). Matrices were harvested, two rats per week, for 15 weeks and examined histologically. At weeks 1 and 2, a thin fibrous capsule was present and matrices showed capillary beds and host-cell infiltration along the implant margins. By week 4, the PL specimens had some arterioles while the PG specimens still had only capillary beds. At week 7, PL had well developed arterioles, venules, and capillaries while PG began to show modest vascular beds of capillaries only. In terms of cellular ingrowth, PL remained unchanged from 7 to 15 weeks. Giant cell formation was observed wherever polymer was present. There was a loss of thickness and cell mass for both matrices over time (PG > PL) despite initial host-cell ingrowth. As both polymers degraded and were absorbed, the ingrown cells mass regressed. There was little remaining PG at 15 weeks, leaving no trace of cells that previously had ingrown and no evidence of scar tissue.

FIRST-TRIMESTER GROWTH PATTERNS OF ANEUPLOID FETUSES

First‐trimester growth restriction has been reported in certain aneuploid pregnancies. The purpose of this study was to evaluate this association further by comparing the crown–rump lengths (CRLs) and growth rates from 196 chromosomally abnormal fetuses with a control population of 1929 euploid fetuses. The mean CRLs and growth rates were significantly reduced (P<0·05) in the groups of fetuses with trisomy 18 (n=49), trisomy 13 (n=19), and triploidy (n=8). Using a fifth percentile cut‐off, growth rate was a better discriminator than a single CRL in identifying fetuses affected with these aneuploidies. These growth parameters were not significantly reduced in fetuses with trisomy 21 (n=92), sex chromosome trisomies (n=20), or 45,X (n=8). We conclude that fetal growth restriction associated with an underlying chromosome abnormality can occur as early as the first trimester. This phenomenon results from intrinsic fetal factors and not delayed ovulation. Such information is important to establish as first‐trimester serum screening evolves.

Clinical Perineal Streptococcal Infection in Children: Epidemiologic Features, Low Symptomatic Recurrence Rate after Treatment, and Risk Factors for Recurrence.

OBJECTIVES To evaluate the epidemiology of perineal streptococcal infection and recurrence rates following amoxicillin treatment. STUDY DESIGN We used laboratory logs in a single pediatric practice to identify patients 0-18 years of age with perineal cultures positive for group A Streptococcus (GAS) and reviewed their medical charts. We described epidemiologic features, determined recurrence rates following antibiotic treatment, and performed a case-control study to identify possible risk factors for recurrence in patients treated with amoxicillin. RESULTS We found a perineal streptococcal infection rate of 4.6 per 10,000 patient encounters and a recurrence rate in 157 patients with perineal streptococcal infection of 12.4% after amoxicillin. In male patients, the predominant site of involvement was the perianal region (86%), and for female patients, the perivaginal area (62%). Nearly 80% of patients were 2-7 years of age (range 18 days-12.5 years). Perineal streptococcal infection and GAS pharyngitis followed a similar seasonal pattern of occurrence with 65% of perineal streptococcal infection occurring October through March. In patients with perineal streptococcal infection, 95% had a concomitant pharyngeal culture positive for GAS. Best predictive factors for recurrence after amoxicillin were longer duration of symptoms prior to diagnosis and having a sibling with perineal streptococcal infection at some time before or after the initial episode. CONCLUSIONS Following treatment with amoxicillin, we found a low recurrence rate of 12.4%. Amoxicillin can be expected to be reliable first-line therapy for perineal streptococcal infection.

Effect of Polyether Ether Ketone on Therapeutic Radiation to the Spine: A Pilot Study.

Study Design. Cadaveric model. Objectives. To compare the effect of PEEK versus conventional implants on scatter radiation to a simulated tumor bed in the spine Summary of Background Data. Given the highly vasculature nature of the spine, it is the most common place for bony metastases. After surgical treatment of a spinal metastasis, adjuvant radiation therapy is typically administered. Radiation dosing is primarily limited by toxicity to the spinal cord. The scatter effect caused by metallic implants decreases the accuracy of dosing and can unintentionally increase the effective dose seen by the spinal cord. This represents a dose-limiting factor for therapeutic radiation postoperatively. Methods. A cadaveric thorax specimen was utilized as a metastatic tumor model with two separate three-level spine constructs (one upper thoracic and one lower thoracic). Each construct was examined independently. All four groups compared included identical posterior instrumentation. The anterior constructs consisted of either: an anterior polyether ether ketone (PEEK) cage, an anterior titanium cage, an anterior bone cement cage (polymethyl methacrylate), or a control group with posterior instrumentation alone. Each construct had six thermoluminescent detectors to measure the radiation dose. Results. The mean dose was similar across all constructs and locations. There was more variability in the upper thoracic spine irrespective of the construct type. The PEEK construct had a more uniform dose distribution with a standard deviation of 9.76. The standard deviation of the others constructs was 14.26 for the control group, 19.31 for the titanium cage, and 21.57 for the cement (polymethyl methacrylate) construct. Conclusion. The PEEK inter-body cage resulted in a significantly more uniform distribution of therapeutic radiation in the spine when compared with the other constructs. This may allow for the application of higher effective dosing to the tumor bed for spinal metastases without increasing spinal cord toxicity with either fractionated or hypofractionated radiotherapy. Level of Evidence: N/A

PC034. Disparities in Outcomes between Genders in Patients With Type B Aortic Dissection Treated With Thoracic Endovascular Aortic Repair

reintervention had a greater renal stent distance (mean, 1.73 6 0.62 stents), as measured from the renal fenestration to the end of the stent, compared with those who did not need an additional renal procedure (2.84 6 0.96 cm vs 2.65 6 1.26 cm; P 1⁄4 .048). Other parameters including preoperative aortic diameter at the renal level, aortic stent graft diameter, and fenestration to renal ostium distance were similar between the two groups (P > .05). Conclusions: There is a trend observed for higher renal reintervention rates with a longer renal stent length. Other variables, such as preoperative aortic diameter, aortic stent graft size, and fenestration to renal ostium distance do not affect renal reinterventions.

Short-term and midterm survival of ruptured abdominal aortic aneurysms in the contemporary endovascular era

Objective: Endovascular aneurysm repair (EVAR) has been shown to reduce mortality in the emergent repair of ruptured abdominal aortic aneurysms (AAAs). However, long‐term survival data for this group of patients are lacking with contemporary endovascular endografts. The purpose of this study was to evaluate both 30‐day mortality rates and 1‐year survival in patients undergoing emergent EVAR in a 43‐facility hospital system with a quaternary referral center with an established ruptured aneurysm protocol. Methods: Retrospective analysis of patients captured prospectively in an Institutional Review Board‐approved registry for patients treated emergently for AAA were reviewed between 2012 and 2017 was conducted. Primary outcome measures were 30‐day mortality and 1‐year survival for the entire group as well as for symptomatic and ruptured aneurysms. Data were analyzed using logistic regression survival curves, and a log‐rank test was performed to compare survival between open and endovascular repair. Patients were evaluated on an intent‐to‐treat basis, and outcomes were evaluated in a multivariate model. Results: A total of 249 patients were referred as part of the protocol. Of these, 102 (41%) were treated emergently. Kaplan‐Meier estimates of 30‐day and 1‐year survival were 64% and 53% for all patients, 58% and 46% for ruptured patients, and 86% and 81% for symptomatic patients. EVAR resulted in improved 30‐day survival (64% vs 31%; odds ratio, 4.0; P = .03) and 1‐year survival (40% vs 23%; odds ratio, 2.3; P = .4) over open repair. Significant predictors for 30‐day mortality included hypotension (P = .0003), blood transfusion (P < .0001), length of stay (P = .0005), extravasation (P = .01), preoperative cardiopulmonary resuscitation (P = .04), open repair (P = .007), aortouni‐iliac reconstruction (P = .008), and abdominal compartment syndrome (P = .007). Significant predictors for 1‐year mortality included advanced age (P = .04), hypotension (P = .01), blood transfusion (P = .006), extravasation (P = .03), reintubation (P = .03), and abdominal compartment syndrome (P = .03). There were no differences in outcomes based on race, gender, or outside transfer. Peripheral arterial disease (P = .04), hypertension (P = .04), coronary artery disease (P = .03), and familial history of aneurysms (P = .05) were related to increased 30‐day mortality. Peripheral arterial disease (P = .06) and coronary artery disease (P = .07) were nearly significant, with increased 1‐year mortality. Conclusions: EVAR is associated with improved survival compared with open repair in patients requiring emergent AAA repair. However, in the first year, there is a significant risk of death based on initial presentation as well as underlying comorbidities. To improve long‐term survival, aggressive medical management and medical surveillance are warranted.