Jaime A. Cavallo

The impact of chemotherapy and radiation therapy on the remodeling of acellular dermal matrices in staged, prosthetic breast reconstruction

Background: An acellular dermal matrix will typically incorporate, in time, with the overlying mastectomy skin flap. This remodeling process may be adversely impacted in patients who require chemotherapy and radiation, which influence neovascularization and cellular proliferation. Methods: Multiple biopsy specimens were procured from 86 women (n = 94 breasts) undergoing exchange of a tissue expander for a breast implant. These were divided by biopsy location: submuscular capsule (control) as well as superiorly, centrally, and inferiorly along the paramedian acellular dermis. Specimens were assessed for cellular infiltration, cell type, fibrous encapsulation, scaffold degradation, extracellular matrix deposition, neovascularization, mean composite remodeling score, and type I and III collagen. Patients were compared based on five oncologic treatment groups: no adjuvant therapy (untreated), neoadjuvant chemotherapy with or without radiation, and chemotherapy with or without radiation. Results: Biopsy specimens were procured 45 to 1805 days after implantation and demonstrated a significant reduction in type I collagen over time. Chemotherapy adversely impacted fibrous encapsulation (p = 0.03). Chemotherapy with or without radiation adversely impacted type I collagen (p = 0.02), cellular infiltration (p < 0.01), extracellular matrix deposition (p < 0.04), and neovascularization (p < 0.01). Radiation exacerbated the adverse impact of chemotherapy for several remodeling parameters. Neoadjuvant chemotherapy also caused a reduction in type I (p = 0.01) and III collagen (p = 0.05), extracellular matrix deposition (p = 0.03), and scaffold degradation (p = 0.02). Conclusion: Chemotherapy and radiation therapy limit acellular dermal matrix remodeling. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Remodeling characteristics and collagen distribution in biological scaffold materials explanted from human subjects after abdominal soft tissue reconstruction: an analysis of scaffold remodeling characteristics by patient risk factors and surgical site classifications.

OBJECTIVE The study purpose was to evaluate the associations between patient characteristics or surgical site classifications and the histologic remodeling scores of biologic meshes biopsied from abdominal soft tissue repair sites in the first attempt to generate a multivariable risk-prediction model of nonconstructive remodeling. BACKGROUND Host characteristics and surgical site assessments may predict remodeling degree for biologic meshes used to reinforce abdominal tissue repair sites. METHODS Biologic meshes were biopsied from the abdominal tissue repair sites of n = 40 patients during an abdominal reexploration, stained with hematoxylin and eosin, and evaluated according to a semi-quantitative scoring system for remodeling characteristics (cell types, cell infiltration, extracellular matrix deposition, scaffold degradation, fibrous encapsulation, and neovascularization) and a mean composite score. Biopsies were stained with Sirius Red and Fast Green and analyzed to determine the collagen I:III ratio. On the basis of univariate analyses between subject clinical characteristics or surgical site classification and the histologic remodeling scores, cohort variables were selected for multivariable regression models using P ≤ 0.200. RESULTS The model selection process for cell infiltration score yielded 2 variables: age at mesh implantation and mesh classification (C statistic = 0.989). For the mean composite score, the model selection process yielded 2 variables: age at mesh implantation and mesh classification (r = 0.449). CONCLUSIONS These preliminary results constitute the first steps in generating a risk-prediction model that predicts the patients and clinical circumstances most likely to experience nonconstructive remodeling of abdominal tissue repair sites with biologic mesh reinforcement.

Remodeling Characteristics and Collagen Distributions of Biologic Scaffold Materials Biopsied From Postmastectomy Breast Reconstruction Sites

ObjectiveThe study purpose was to evaluate the associations between patient characteristics and the histologic remodeling scores of acellular dermal matrices (ADMs) biopsied from breast reconstruction sites in the first attempt to generate a multivariable risk prediction model of nonconstructive remodeling. It was hypothesized that host characteristics and surgical site assessments predict the degree of graft remodeling for ADMs used during breast reconstruction. MethodsThe ADMs were biopsied from the breast reconstruction sites of n = 62 patients during a subsequent breast procedure, stained with hematoxylin-eosin, and evaluated according to a semi-quantitative scoring system for remodeling characteristics (cell types, cell infiltration, extracellular matrix deposition, scaffold degradation, fibrous encapsulation, and neovascularization) and a mean composite score. Biopsies were stained with Sirius Red and Fast Green, and analyzed to determine the collagen I:III ratio. Based on univariate analyses between subject clinical characteristics and the histologic remodeling scores, cohort variables were selected for multivariable regression models using a P value of 0.20 or less. ResultsThe composite score model yielded 3 variables: pack-year history, corticosteroid use, and radiation timing (r2 pseudo = 0.81). The model for collagen I yielded 2 variables: corticosteroid use and reason for reoperation (r2 pseudo = 0.78). The model for collagen III yielded 1 variable: reason for reoperation (r2 pseudo = 0.35). ConclusionsThese preliminary results constitute the first steps in generating a risk prediction model that predicts the patients and clinical circumstances most likely to experience nonconstructive remodeling of biologic grafts used to reconstruct the breast.

Malignant and Metastatic Pheochromocytoma: Case Report and Review of the Literature.

Pheochromocytomas are rare neuroendocrine tumors. Although predominantly occurring in the adrenal glands, these tumors can present anywhere along the sympathetic chain. Indeed, classical teaching states that 10% of pheochromocytomas are extra-adrenal and 10% are malignant. We report a case of a 61-year-old female who underwent presumptive cytoreductive nephrectomy and adrenalectomy for renal carcinoma but was instead found to have malignant pheochromocytoma. Proper identification, surgical extirpation, and follow-up are imperative for treatment. We review the classic and current literature regarding management of this uncommon tumor.

Analysis of surgical motions in minimally invasive surgery using complexity theory

Traditional Minimally Invasive Surgery (MIS) training paradigm in which interns and junior residents perform operations under the supervision of faculty surgeons lacks objective means of assessing surgical skills. This paper studies novel real–time measures that can dynamically quantify surgical motions. In this study, the proposed measures were tested through two phases of experimental study. In the first phase, ten volunteered subjects who have no prior experience of MIS completed three trials of a surgical exercise using a laparoscopic instrument on which a motion sensor was attached. In the second phase, an MIS surgeon performed three standard surgical exercises with five replications. Then, time–delay and Hurst exponent analysis were used to measure the degree of synchronisation in surgical motions. As the results, improvement in surgical motions was observed such that the range and thickness of time–delay plots are reduced while Hurst exponents increase, as the subjects gain experience.

Biologic Mesh: When and Why—A Critical Appraisal

The US markets for soft tissue repair report prepared by the Millennium Research Group estimates that 305,900 ventral hernias were performed in the United States in 2006 [1], reaffirming ventral hernia repair as one of the most common procedures in general surgery. The 10-year cumulative rate of recurrence for suture repair of ventral hernias is as high as 63 %, which contributes to the high incidence of repair [2]. Significant risk factors for recurrence include surgical technique, history of previous failed hernia repairs, large hernia size, obesity, smoking habits, and patient comorbidities that contribute to diminished soft tissue integrity. To reduce recurrence to a 10-year cumulative rate <32 %, level A and B evidence supports reinforcement with synthetic or biologic materials for all incisional ventral hernia repairs [2, 3]. Likely attributable to evidence-based recommendations for material reinforcement, it is estimated that synthetic or biologic reinforcement materials were used in nearly 95 % of the ventral hernias performed in the United States in 2006 [1]. Market analysts predict a 7 % annual growth rate in the The US markets for soft tissue repair report prepared by the Millennium Research Group estimates that 305,900 ventral hernias were performed in the United States in 2006 [1], reaffirming ventral hernia repair as one of the most common procedures in general surgery. The 10-year cumulative rate of recurrence for suture repair of ventral hernias is as high as 63 %, which contributes to the high incidence of repair [2]. Significant risk factors for recurrence include surgical technique, history of previous failed hernia repairs, large hernia size, obesity, smoking habits, and patient comorbidities that contribute to diminished soft tissue integrity. To reduce recurrence to a 10-year cumulative rate <32 %, level A and B evidence supports reinforcement with synthetic or biologic materials for all incisional ventral hernia repairs [2, 3]. Likely attributable to evidence-based recommendations for material reinforcement, it is estimated that synthetic or biologic reinforcement materials were used in nearly 95 % of the ventral hernias performed in the United States in 2006 [1]. Market analysts predict a 7 % annual growth rate in the

Ergonomic analysis of robot-assisted and traditional laparoscopic procedures

1 billion United States soft tissue repair device industry, largely impelled by costly biologic scaffold materials for ventral hernia repair. The aging patient population, the prevalence of comorbidities contributing to diminished soft tissue integrity, the high incidence of obesity, and the rising demand for bariatric procedures with high potential for sequelae of incisional ventral hernias are major factors driving the anticipated market expansion for ventral hernia reinforcement materials. In particular, demand for biologic scaffold materials is expected to expand based on preclinical evidence that biologic materials enable revascularization of soft tissue repair sites and improved pathogen clearance in contaminated and infected surgical sites [4, 5] and clinical evidence that biologic materials do not necessarily require removal when exposed or infected [6–8]. billion United States soft tissue repair device industry, largely impelled by costly biologic scaffold materials for ventral hernia repair. The aging patient population, the prevalence of comorbidities contributing to diminished soft tissue integrity, the high incidence of obesity, and the rising demand for bariatric procedures with high potential for sequelae of incisional ventral hernias are major factors driving the anticipated market expansion for ventral hernia reinforcement materials. In particular, demand for biologic scaffold materials is expected to expand based on preclinical evidence that biologic materials enable revascularization of soft tissue repair sites and improved pathogen clearance in contaminated and infected surgical sites [4, 5] and clinical evidence that biologic materials do not necessarily require removal when exposed or infected [6–8].