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Dive into the research topics where Ronnie L. Shammas is active.

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Featured researches published by Ronnie L. Shammas.


Spine | 2016

Risk Assessment And Characterization of 30-Day Perioperative Myocardial Infarction Following Spine Surgery: A Retrospective Analysis of 1346 Consecutive Adult Patients.

Timothy Y. Wang; Martin; Daniel B. Loriaux; Rupen Desai; Ronnie L. Shammas; Owoicho Adogwa; Jessica R. Moreno; Maragatha Kuchibhatla; Carlos A. Bagley; Isaac O. Karikari; Oren N. Gottfried

Study Design. A retrospective review. Objective. The aim of the study was to perform a risk assessment of 30-day perioperative myocardial infarction (MI) for spine surgery patients. Summary of Background Data. There is an increased emphasis to reduce complications and improve outcomes after spinal surgery. One of the more devastating perioperative complications of spinal surgery is MI. Methods. We evaluated all medical records of 1346 consecutive patients who underwent spinal surgery at a single institution from 2008 to 2010 for incidence of MI within 30 days of surgery and documented all demographic, preoperative, and operative variables. Associations between postoperative MI and individual risk factors were determined using logistic regression analysis. Patients were stratified into emergent and elective groups and a similar analysis was performed. Results. Overall, 22 patients (1.6%) had 30-day perioperative MI, 14 patients (1.2%) undergoing elective surgery, and 8 patients (4.2%) after emergent surgery (P = 0.047). Three (13.6%) patients experienced 30-day mortality and an additional 3 (13.6%) patients experienced mortality within 1 year. Multivariate logistic regression determined that age more than 65 years, atrial fibrillation, hypertension, prior MI, anticoagulant use, low albumin, length of stay more than 7 days, intraoperative transfusion, trauma etiology, baseline creatinine more than 1 mg/dL, and at least 2 levels of spinal fusion were predictive of postoperative MI. For patients undergoing emergent surgery, age more than 65 years was associated with an increased risk of postoperative MI. When stratified by elective surgery, we found that age more than 65, postoperative stay more than 7 days, intraoperative blood transfusion, baseline creatinine more than 1 mg/dL, and fusion of more than 1 level were associated with an increased risk of MI. Conclusion. The present study demonstrates a low incidence of MI after elective surgery with a higher incidence after emergent spine surgery and identifies patient factors predictive of postoperative MI. Level of Evidence: 3


Plastic and Reconstructive Surgery | 2017

Preoperative Platelet Count Predicts Lower Extremity Free Flap Thrombosis: A Multi-Institutional Experience.

Eugenia H. Cho; Andrew R. Bauder; Centkowski S; Ronnie L. Shammas; Lily R. Mundy; Stephen J. Kovach; Levin Ls; Scott T. Hollenbeck

Background: Thrombocytosis in patients undergoing lower extremity free tissue transfer may be associated with increased risk of microvascular complications. This study assessed whether preoperative platelet counts predict lower extremity free flap thrombosis. Methods: All patients undergoing lower extremity free tissue transfer at Duke University from 1997 to 2013 and at the University of Pennsylvania from 2002 to 2013 were retrospectively identified. Logistic regression was used to assess whether preoperative platelet counts independently predict flap thrombosis, controlling for baseline and operative factors. Results: A total of 565 patients underwent lower extremity free tissue transfer, with an overall flap thrombosis rate of 16 percent (n = 91). Elevated preoperative platelet counts were independently associated with both intraoperative thrombosis (500 ± 120 versus 316 ± 144 × 109/liter; p < 0.001) and postoperative thrombosis (410 ± 183 versus 320 ± 143 × 109/liter; p = 0.040) in 215 patients who sustained acute lower extremity trauma within 30 days before reconstruction. In acute trauma patients, preoperative platelet counts predicted a four-fold increased risk of intraoperative thrombosis (cutoff value, 403 × 109/liter; OR, 4.08; p < 0.001) and a two-fold increased risk of postoperative thrombosis (cutoff value, 361 × 109/liter; OR, 2.16; p = 0.005). In patients who did not sustain acute trauma, preoperative platelet counts predicted a four-fold increased risk of intraoperative thrombosis (cutoff value, 352 × 109/liter; OR, 3.82; p = 0.002). Conclusions: Acute trauma patients with elevated preoperative platelet counts are at increased risk for lower extremity free flap complications. Prospective evaluation is warranted for guiding risk stratification and targeted treatment strategies. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, III.


Journal of Reconstructive Microsurgery | 2017

Institutional Outcomes of Leech Therapy for Venous Congestion in 87 Patients

Agustin Cornejo; Ronnie L. Shammas; Luke P. Poveromo; Hui-Jie Lee; Scott T. Hollenbeck

Background We aimed to report the outcomes associated with leech therapy and to identify risk factors associated with reconstructive failure. Methods We retrospectively reviewed cases of flap reconstruction or replanted appendages that required leech therapy over an 8‐year period at the Duke University Medical Center. Using logistic regression, we assessed the association of risk factors with reconstructive failure. Results The study cohort included 87 patients which correspond to 2.1% of 4,115 cases done during the study period. The most common flap recipient site was the lower extremity (n = 33, 37.9%) followed by the upper extremity (n = 30, 34.5%), head and neck (n = 13, 14.9%), and trunk (n = 11, 12.6%). Flap types were pedicled in 44 (50.5%) cases and free in 24 (27.5%) cases. Fifteen (17.2%) were digital replantation, and four (4.5%) were replanted appendages. The average duration of therapy was 4.6 days (range: 1‐11). The overall leech therapy success rate was 60.9% (53/87) and accounted for cases without flap loss (n = 45, 51.7%) and with partial flap loss in which the original reconstructive goal was achieved without further reconstructive procedures (n = 8, 9.2%). Postoperative blood transfusion was administered in 32 (36.7%) cases, and infectious complications occurred in 7 cases in spite of the administration of prophylactic antibiotics (8%). Conclusions This study represents the largest single‐institution series evaluating the outcomes after leech therapy. Our data support the use of leeches as an adjunct for the management of venous congestion after reconstructive surgery. However, the morbidity associated with it should be considered, particularly the need for a blood transfusion.


Journal of Reconstructive Microsurgery | 2017

Acute Treatment Patterns for Lower Extremity Trauma in the United States: Flaps versus Amputation

Lily R. Mundy; Tracy Truong; Ronnie L. Shammas; Mark J. Gage; Gina-Maria Pomann; Scott T. Hollenbeck

Background Treatment algorithms for large soft tissue defects in lower extremity trauma are not clearly defined. The aim of this study is to determine if there are geographic or demographic differences in the management of open tibia fractures with soft tissue defects requiring either soft tissue reconstruction or amputation in the United States (US). Methods A retrospective analysis was performed on the Nationwide Inpatient Sample (NIS), 2000 to 2011. We evaluated flap and amputation rates in the open tibia fractures with soft tissue defects based on geographic and socioeconomic factors. Results From 2000 to 2011, there were 175,283 open tibia fractures in the US; 7.2% (n = 12,620) had a concomitant soft tissue defect requiring either flap or amputation. The overall flap rate was 73.2% (n = 9,235). When compared with the South at 68%, flap rates were highest in the West at 79% (adjusted odds ratio [AOR] = 2.06; 95% confidence interval [CI] = 1.49, 2.86; p < 0.0001), followed by the Northeast at 77% (AOR = 1.63; 95% CI = 1.22, 2.19; p = 0.001), and the Midwest at 74% (AOR = 1.76; 95% CI = 1.25, 2.47; p = 0.001). Flap rates were lower in the rural hospitals in the West (AOR = 0.24; 95% CI = 0.07, 0.84; p = 0.03) and Northeast (AOR = 0.55; 95% CI = 0.37, 0.82; p = 0.003) when compared with the urban hospitals. Flap rates were highest in the highest income quartile at 77% (AOR = 1.53; 95% CI = 1.05, 2.25; p = 0.03) compared with 72% in the lowest income quartile. Conclusions Reconstruction rates were significantly higher in three major US regions when compared with the South, urban hospitals in the West and Northeast, and the highest income quartile.


Plastic and reconstructive surgery. Global open | 2017

A Population-Based Exploration of the Social Implications Associated with Cleft Lip and/or Palate

Adam D. Glener; Alexander C. Allori; Ronnie L. Shammas; Anna R. Carlson; Irene J. Pien; Arthur S. Aylsworth; Robert E. Meyer; Luiz Pimenta; Ronald P. Strauss; Stephanie Watkins; Jeffrey R. Marcus

Background: Clefts of the lip and/or palate (CL/P) carry a social stigma that often causes psychosocial stress. The purpose of this study was to consider the association of cleft phenotype and age with self-reported aspects of psychosocial stress. Methods: Children with nonsyndromic CL/P and unaffected children born between 1997 and 2003 were identified through the North Carolina Birth Defects Monitoring Program and North Carolina birth records, respectively. The psychosocial concerns of children with CL/P were assessed via a 29-question subset of a larger survey. Responses were analyzed according to school age and cleft phenotype (cleft lip with/without cleft alveolus, CL ± A; cleft palate only, CP; or cleft lip with cleft palate, CL + P). Results: Surveys were returned for 176 children with CL/P and 333 unaffected children. When compared with unaffected children, responses differed for CL ± A in 4/29 questions, for CP in 7/29 questions, and for CL + P in 8/29 questions (P < 0.05). When stratified by school age, children with CL/P in elementary, middle, and high school differed from unaffected children by 1/29, 7/29, and 2/29 questions, respectively. Middle school–aged children with CL/P were more affected by aesthetic concerns, bullying, and difficulties with friendship, and social interaction. Children with CL + P reported more severe aesthetic-related concerns than children with CL ± A or CP but experienced similar speech-related distress as children with CP only. Conclusion: Social implications associated with CL/P are most pronounced during middle school, and less so during elementary and high school. This information identifies areas of social improvement aimed at reducing the stigma of CL/P.


Plastic and Reconstructive Surgery | 2017

Human Adipose-Derived Stem Cells Labeled with Plasmonic Gold Nanostars for Cellular Tracking and Photothermal Cancer Cell Ablation.

Ronnie L. Shammas; Andrew M. Fales; Bridget M. Crawford; Amy J. Wisdom; Gayathri R. Devi; David A. Brown; Tuan Vo-Dinh; Scott T. Hollenbeck

Background: Gold nanostars are unique nanoplatforms that can be imaged in real time and transform light energy into heat to ablate cells. Adipose-derived stem cells migrate toward tumor niches in response to chemokines. The ability of adipose-derived stem cells to migrate and integrate into tumors makes them ideal vehicles for the targeted delivery of cancer nanotherapeutics. Methods: To test the labeling efficiency of gold nanostars, undifferentiated adipose-derived stem cells were incubated with gold nanostars and a commercially available nanoparticle (Qtracker), then imaged using two-photon photoluminescence microscopy. The effects of gold nanostars on cell phenotype, proliferation, and viability were assessed with flow cytometry, 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide metabolic assay, and trypan blue, respectively. Trilineage differentiation of gold nanostar–labeled adipose-derived stem cells was induced with the appropriate media. Photothermolysis was performed on adipose-derived stem cells cultured alone or in co-culture with SKBR3 cancer cells. Results: Efficient uptake of gold nanostars occurred in adipose-derived stem cells, with persistence of the luminescent signal over 4 days. Labeling efficiency and signal quality were greater than with Qtracker. Gold nanostars did not affect cell phenotype, viability, or proliferation, and exhibited stronger luminescence than Qtracker throughout differentiation. Zones of complete ablation surrounding the gold nanostar–labeled adipose-derived stem cells were observed following photothermolysis in both monoculture and co-culture models. Conclusions: Gold nanostars effectively label adipose-derived stem cells without altering cell phenotype. Once labeled, photoactivation of gold nanostar–labeled adipose-derived stem cells ablates neighboring cancer cells, demonstrating the potential of adipose-derived stem cells as a vehicle for the delivery of site-specific cancer therapy.


Plastic and Reconstructive Surgery | 2017

Breast Cancer after Augmentation: Oncologic and Reconstructive Considerations among Women Undergoing Mastectomy

Eugenia H. Cho; Ronnie L. Shammas; Brett T. Phillips; Rachel A. Greenup; E. Shelley Hwang; Scott T. Hollenbeck

Background: Breast augmentation with subglandular versus subpectoral implants may differentially impact the early detection of breast cancer and treatment recommendations. The authors assessed the impact of prior augmentation on the diagnosis and management of breast cancer in women undergoing mastectomy. Methods: Breast cancer diagnosis and management were retrospectively analyzed in all women with prior augmentation undergoing therapeutic mastectomy at the authors’ institution from 1993 to 2014. Comparison was made to all women with no prior augmentation undergoing mastectomy in 2010. Subanalyses were performed according to prior implant placement. Results: A total of 260 women with (n = 89) and without (n = 171) prior augmentation underwent mastectomy for 95 and 179 breast cancers, respectively. Prior implant placement was subglandular (n = 27) or subpectoral (n = 63) (For five breasts, the placement was unknown). Breast cancer stage at diagnosis (p = 0.19) and detection method (p = 0.48) did not differ for women with and without prior augmentation. Compared to subpectoral augmentation, subglandular augmentation was associated with the diagnosis of invasive breast cancer rather than ductal carcinoma in situ (p = 0.01) and detection by self-palpation rather than screening mammography (p = 0.03). Immediate two-stage implant reconstruction was the preferred reconstructive method in women with augmentation (p < 0.01). Conclusions: Breast cancer stage at diagnosis was similar for women with and without prior augmentation. Among women with augmentation, however, subglandular implants were associated with more advanced breast tumors commonly detected on palpation rather than mammography. Increased vigilance in breast cancer screening is recommended among women with subglandular augmentation. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.


International Journal of Nanomedicine | 2017

Photothermal ablation of inflammatory breast cancer tumor emboli using plasmonic gold nanostars

Bridget M. Crawford; Ronnie L. Shammas; Andrew M. Fales; David A. Brown; Scott T. Hollenbeck; Tuan Vo-Dinh; Gayathri R. Devi

Inflammatory breast cancer (IBC) is rare, but it is the most aggressive subtype of breast cancer. IBC has a unique presentation of diffuse tumor cell clusters called tumor emboli in the dermis of the chest wall that block lymph vessels causing a painful, erythematous, and edematous breast. Lack of effective therapeutic treatments has caused mortality rates of this cancer to reach 20%–30% in case of women with stage III–IV disease. Plasmonic nanoparticles, via photothermal ablation, are emerging as lead candidates in next-generation cancer treatment for site-specific cell death. Plasmonic gold nanostars (GNS) have an extremely large two-photon luminescence cross-section that allows real-time imaging through multiphoton microscopy, as well as superior photothermal conversion efficiency with highly concentrated heating due to its tip-enhanced plasmonic effect. To effectively study the use of GNS as a clinically plausible treatment of IBC, accurate three-dimensional (3D) preclinical models are needed. Here, we demonstrate a unique in vitro preclinical model that mimics the tumor emboli structures assumed by IBC in vivo using IBC cell lines SUM149 and SUM190. Furthermore, we demonstrate that GNS are endocytosed into multiple cancer cell lines irrespective of receptor status or drug resistance and that these nanoparticles penetrate the tumor embolic core in 3D culture, allowing effective photothermal ablation of the IBC tumor emboli. These results not only provide an avenue for optimizing the diagnostic and therapeutic application of GNS in the treatment of IBC but also support the continuous development of 3D in vitro models for investigating the efficacy of photothermal therapy as well as to further evaluate photothermal therapy in an IBC in vivo model.


The Journal of Spine Surgery | 2018

Post-operative drain use in patients undergoing decompression and fusion: incidence of complications and symptomatic hematoma

Owoicho Adogwa; Aladine A. Elsamadicy; Amanda Sergesketter; Ronnie L. Shammas; Sohrab Vatsia; Victoria D. Vuong; Syed I. Khalid; Joseph S. Cheng; Carlos A. Bagley; Isaac O. Karikari

Background Surgical drains are commonly used after spine surgery to minimize infection and hematoma formation. The aim of this study was to determine the incidence of post-operative complications after spinal decompression and fusion with and without a subfascial drain. Methods The medical records of 139 adult (≥18 years old) spinal deformity patients undergoing elective spinal decompression and fusion at a major academic institution were reviewed. We identified 116 (83.5%) who had a post-operative drain and 23 (16.5%) who did not have a postoperative drain (No-Drain: n=23; Drain-Use: n=116). Patient demographics, comorbidities, intra- and post-operative complication rates were collected for each patient. The primary outcome investigated in this study was the rate of post-operative complications, specifically surgical site infections (SSI) and hematoma formation. Results Patient demographics and comorbidities were similar between both cohorts, with the body mass index (BMI) slightly higher in the Drain-Use cohort (No-Drain: 26.1 kg/m2vs. Drain-Use: 29.1 kg/m2, P=0.02). Operative time and the median number of levels fused were similar between the cohorts. The postoperative complications profile was similar between both cohorts, including deep and superficial SSIs (P=0.52 and P=0.66, respectively), and incidence of hematoma formation (P=0.66). Length of hospital stay (LOS) was significantly higher for the Drain-use cohort compared to the No-Drain cohort (5.0 vs. 2.8 days, P<0.0001). There were no significant differences in the 30-day hospital readmission rate or incidence of 30-day wound dehiscence, draining wound, incision & drainage (I & D), or bleeding between both patient groups. Conclusions Our study suggests that the use of postoperative subfascial drains in patients undergoing spinal decompression with fusion may not be associated with a reduction in SSIs or hematoma formation.


Archive | 2018

Use of Magnetic Resonance Imaging to Help Avoid Skin Necrosis After Nipple-Sparing Mastectomy

Ronnie L. Shammas; Scott T. Hollenbeck

Nipple-areola ischemia and skin flap necrosis are complications that may occur after nipple-sparing mastectomy. The rate of these complications is dependent on many factors including age, comorbidities, and incisional pattern. Furthermore, the extent and occurrence of these complications may be dependent on the pattern of the arterial blood supply to the nipple-areolar complex. Preoperative magnetic resonance imaging may be helpful in choosing the ideal candidate for a nipple-sparing mastectomy, by characterizing the vascular pattern of the nipple-areolar complex. This imaging technique will help guide the physician on the most appropriate incisional pattern that minimizes the risk of vascular compromise to the nipple while also delineating the blood flow pattern to the nipple as unilateral or bilateral.

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