Comparative Perfusion Analysis of Free Muscle-Sparing Versus Pedicle Transverse Rectus Abdominis Myocutaneous (TRAM) Flaps in Vivo in the Peri-Operative and Late Post-Operative Periods.

BACKGROUND: Current teaching suggests increased perfusion in free transverse rectus abdominis myocutaneous (TRAM) flaps over pedicled TRAM flaps, broadening indications for its use in high risk patients. This study compared perfusion analysis of free muscle-sparing versus pedicle TRAM flaps in vivo in the peri-operative and late post-operative periods. METHODS: The SPY-Elite system using indocyanine green dye was used to analyze flap perfusion intra-operatively and at 1 week and 3 months post-operatively. Image analysis was completed by evaluating the perfusion maps from the SPY- Elite system with Image J software calculate maximum, minimum, and average luminescence over the surface area of the flaps. Student's T-test was used for statistical analysis. RESULTS: Intra-operatively, we found a 73.4% greater perfusion in the free muscle-sparing as compared to the pedicled TRAM. This increase in free muscle-sparing TRAM perfusion was not evident 1 week post-operatively, due to a relative increase in pedicle flap perfusion that coincided with a revision of the pedicled flap due to distal flap necrosis. At 3 months, the free muscle-sparing TRAM flap once again showed superior perfusion with a 15.7% increase over the pedicled flap. CONCLUSION: We showed superior free muscle-sparing TRAM perfusion in the early peri-operative period which coincided with the time framein which flap loss was most common. Local swelling, pedicle rotation, tunneling, and dominance of the deep inferior epigastric circulation were potential causes of initial decreased pedicled TRAM perfusion. This analysis adds more objective data to the question of indications and relative strengths between free and pedicled TRAM flaps.

Venous Thromboembolism: A Comparison of Chronic Spinal Cord Injury and General Surgery Patients in a Metropolitan Veterans Affairs Hospital.

BACKGROUND: Venous thromboembolic events result in significant morbidity, mortality, and costly therapeutic interventions. As medical resource allocation strategies are becoming more pervasive, appropriate risk stratification and prophylactic regimens are essential. Previous studies have shown a decreased incidence of perioperative venous thromboembolism in the chronic spinal cord injury population. The question remains of whether chronic spinal cord injury is protective against venous thromboembolism. METHODS: A retrospective review of all cases involving chronic spinal cord injury patients who underwent plastic and reconstructive surgery operations (n = 424) and general surgery patients (n = 777) with a primary outcome of deep venous thrombosis or pulmonary embolism within 90 days of surgery was performed. RESULTS: The incidence of postoperative deep venous thrombosis in the control and spinal cord injury groups was 1.7 percent and 0.2 percent, respectively (p = 0.027). However, such significance was not observed with regard to postoperative pulmonary embolism incidence (p = 0.070). Collectively, the incidence of postoperative venous thromboembolism-specifically, deep venous thrombosis or pulmonary embolism-was significantly greater in the general surgery population (p = 0.014). A nearly 10-fold increased risk of venous thromboembolism was seen among the control group (1.9 percent versus 0.2 percent) despite administration of optimal prophylaxis. CONCLUSIONS: This study demonstrates a profoundly low incidence of venous thromboembolism among chronic spinal cord injury patients compared with general surgery patients. Future efforts to elucidate how chronic spinal cord injury confers a protective mechanism may potentially influence the evolution of venous thromboembolism prevention guidelines, and spark the development of alternative prophylactic agents or customized application of prevention efforts.

Evaluating visual perception for assessing reconstructed flap health.

BACKGROUND: Detecting failing tissue flaps before they are clinically apparent has the potential to improve postoperative flap management and salvage rates. This study demonstrates a model to quantitatively compare clinical appearance, as recorded via digital camera, with spatial frequency domain imaging (SFDI), a noninvasive imaging technique using patterned illumination to generate images of total hemoglobin and tissue oxygen saturation (stO2). METHODS: Using a swine pedicle model in which blood flow was carefully controlled with occlusion cuffs and monitored with ultrasound probes, throughput was reduced by 25%, 50%, 75%, and 100% of baseline values in either the artery or the vein of each of the flaps. The color changes recorded by a digital camera were quantified to predict which occlusion levels were visible to the human eye. SFDI was also used to quantify the changes in physiological parameters including total hemoglobin and oxygen saturation associated with each occlusion. RESULTS: There were no statistically significant changes in color above the noticeable perception levels associated with human vision during any of the occlusion levels. However, there were statistically significant changes in total hemoglobin and stO2 levels detected at the 50%, 75%, and 100% occlusion levels for arterial and venous occlusions. CONCLUSIONS: As demonstrated by the color imaging data, visual flap changes are difficult to detect until significant occlusion has occurred. SFDI is capable of detecting changes in total hemoglobin and stO2 as a result of partial occlusions before they are perceivable, thereby potentially improving response times and salvage rates.

Frequency and risk factors of blood transfusion in abdominoplasty in post-bariatric surgery patients: data from the nationwide inpatient sample.

BACKGROUND: There are limited data regarding blood transfusion following abdominoplasty, especially in post-bariatric surgery patients. The purpose of this study was to evaluate (1) the frequency and outcomes of blood transfusion in post-bariatric surgery patients undergoing abdominoplasty and (2) the predictive risk factors of blood transfusion in this patient population. METHODS: Using the Nationwide Inpatient Sample database, the authors examined the clinical data of patients with a history of bariatric surgery who underwent abdominoplasty from 2007 to 2011 in the United States. RESULTS: A total of 20,130 post-bariatric surgery patients underwent abdominoplasty during this period. Overall, 1871 patients (9.3 percent) received blood transfusion. Chronic anemia patients had the highest rate of blood transfusion (25.6 percent). Post-bariatric surgery patients who received blood transfusion experienced a significantly higher complication rate (10.1 percent versus 4.8 percent; p < 0.01), longer mean hospital stay (4.0 days versus 2.4 days; p < 0.01), and higher mean total hospital charges ($49,116 versus $33,927; p < 0.01). Multivariate regression analysis showed that deficiency anemia (adjusted OR, 3.8), congestive heart failure (adjusted OR, 2.4), concurrent breast reduction (adjusted OR, 1.5), diabetes mellitus (adjusted OR, 1.4), coronary artery disease (adjusted OR, 1.4), African American race (adjusted OR, 1.4), Hispanic race (adjusted OR, 1.4), and female sex (adjusted OR, 1.3) were all independent risk factors for blood transfusion. CONCLUSIONS: The blood transfusion rate in post-bariatric surgery abdominoplasty patients is not insignificant. Chronic anemia and congestive heart failure are the two major predictors of transfusion. Modifying risk factors such as anemia before abdominoplasty might significantly decrease the possibility of blood transfusion. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, III.

"NACsomes": A new classification system of the blood supply to the nipple areola complex (NAC) based on diagnostic breast MRI exams.

BACKGROUND: Breast MRIs have become increasingly common in breast cancer work-up. Previously obtained breast MRIs may facilitate oncoplastic surgery by delineating the blood supply to the nipple-areola complex (NAC). The aim of this study was to identify and classify the in vivo blood supply to the NAC using breast MRI exams. METHODS: Breast MRIs obtained over a one-year period were retrospectively reviewed. Patients with negative MRI findings (BI-RADS category 1) were included; patients with diagnoses of breast cancer or previous breast surgery were excluded. Twenty-six patients were evaluated. Dominant blood supply was determined by maximum filling at 70 s post-contrast. Blood supply to the NAC was classified into five anatomic zones: medial (type I), lateral (type II), central (type III), inferior (type IV) and superior (type V). RESULTS: Patient age ranged from 33 to 70 years. Fifty-two breasts were evaluated and 80 source vessels were identified (37 right, 43 left). Twenty-eight breasts had type I only blood supply, 22 breasts had multi-zone blood supply (type I + II, n = 20; type I + III n = 2), one breast had type II only blood supply, and a single breast had type III only blood supply. Anatomic symmetry was observed in 96% of patients. CONCLUSION: This study utilized MRI to evaluate in vivo vascular anatomy of the NAC, classify NAC perfusion ("NACsomes"), and assess vascular symmetry between breasts. Superomedial source vessels supplying the NAC were predominant. Preoperatively defining NAC blood supply may aid planning for oncoplastic procedures.

Quantitative assessment of partial vascular occlusions in a swine pedicle flap model using spatial frequency domain imaging.

The use of tissue transfer flaps has become a common and effective technique for reconstructing or replacing damaged tissue. While the overall failure rate associated with these procedures is relatively low (5-10%), the failure rate of tissue flaps that require additional surgery is significantly higher (40-60%). The reason for this is largely due to the absence of a technique for objectively assessing tissue health after surgery. Here we have investigated spatial frequency domain imaging (SFDI) as a potential tool to do this. By projecting wide-field patterned illumination at multiple wavelengths onto a tissue surface, SFDI is able to quantify absolute concentrations of oxygenated and deoxygenated hemoglobin over a large field of view. We have assessed the sensitivity of SFDI in a swine pedicle flap model by using a controlled vascular occlusion system that reduced blood flow by 25%, 50%, 75%, or 100% of the baseline values in either the vein or artery. SFDI was able to detect significant changes for oxygenated hemoglobin, deoxygenated hemoglobin, or tissue oxygen saturation in partial arterial occlusions of at least 50% and partial venous occlusions of at least 25%. This shows SFDI is sensitive enough to quantify changes in the tissue hemoglobin state during partial occlusions and thus has the potential to be a powerful tool for the early prediction of tissue flap failure.

The incidence of venous thromboembolism in postoperative plastic and reconstructive surgery patients with chronic spinal cord injury.

BACKGROUND: The purpose of this study was to investigate the incidence of postoperative venous thromboembolism in chronic spinal cord injury patients undergoing plastic and reconstructive surgery. Previous studies show a venous thromboembolism incidence of 9.3 percent; however, based on anecdotal evidence, the authors hypothesize that the incidence is actually much lower. As postoperative venous thromboembolism prophylaxis is becoming mandated by the Surgical Care Improvement Project, more data are necessary so that recommendations for chronic spinal cord injury patients can be given. METHODS: A retrospective chart review was undertaken using electronic medical records from a Veterans Affairs hospital from 2004 through 2009 in which the perioperative course of the chronic spinal cord injury cohort was evaluated for the primary endpoint of venous thromboembolism evolution. The Pearson correlation was used for statistical analysis. RESULTS: Of the 415 operative cases evaluated, 155 cases were excluded secondary to operative time under 1 hour, use of mechanical or chemical venous thromboembolism prophylaxis, unknown operative time, or unknown prophylaxis use. Of the 260 cases evaluated without venous thromboembolism prophylaxis, there were no cases where venous thromboembolism developed within a 2-month postoperative time period. CONCLUSIONS: Postoperative venous thromboembolism is a common surgical complication with significant morbidity and mortality. This study demonstrates that in the chronic spinal cord injury patient cohort, the incidence of postoperative venous thromboembolism evolution is extremely low and that a benefit from perioperative mechanical or chemical prophylaxis is not evidence based. Further prospective studies are required to fully elucidate the true venous thromboembolism incidence in these patients and give recommendations on this issue. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.