In JoVE (1)

Other Publications (22)

Articles by Michael Gart in JoVE

 JoVE Bioengineering

Quantification of Strain in a Porcine Model of Skin Expansion Using Multi-View Stereo and Isogeometric Kinematics

1Mechanical Engineering, Purdue University, 2Division of Plastic Surgery, Ann and Robert H. Lurie Children's Hospital of Chicago, Northwestern University Feinberg School of Medicine, 3Mechanical Engineering, Bioengineering, Cardiothoracic Surgery, Stanford University


JoVE 55052

Other articles by Michael Gart on PubMed

Neutrophil Depletion Blocks Early Collagen Degradation in Repairing Cholestatic Rat Livers

The American Journal of Pathology. Mar, 2010  |  Pubmed ID: 20110408

Biliary obstruction results in a well-characterized cholestatic inflammatory and fibrogenic process; however, the mechanisms and potential for liver repair remain unclear. We previously demonstrated that Kupffer cell depletion reduces polymorphonuclear cell (neutrophil) (PMN) and matrix metalloproteinase (MMP)8 levels in repairing liver. We therefore hypothesized that PMN-dependent MMP activity is essential for successful repair. Male Sprague-Dawley rats received reversible biliary obstruction for 7 days, and the rat PMN-specific antibody RP3 was administered 2 days before biliary decompression (repair) and continued daily until necropsy, when liver underwent morphometric analysis, immunohistochemistry, quantitative RT-PCR, and in situ zymography. We found that RP3 treatment did not reduce Kupffer cell or monocyte number but significantly reduced PMN number at the time of decompression and 2 days after repair. RP3 treatment also blocked resorption of type I collagen. In addition, biliary obstruction resulted in increased expression of MMP3, MMP8, and tissue inhibitor of metalloproteinase 1. Two days after biliary decompression, both MMP3 and tissue inhibitor of metalloproteinase 1 expression declined toward sham levels, whereas MMP8 expression remained elevated and was identified in bile duct epithelial cells by immunohistochemistry. PMN depletion did not alter the hepatic expression of these genes. Conversely, collagen-based in situ zymography demonstrated markedly diminished collagenase activity following PMN depletion. We conclude that PMNs are essential for collagenase activity and collagen resorption during liver repair, and speculate that PMN-derived MMP8 or PMN-mediated activation of intrinsic hepatic MMPs are responsible for successful liver repair.

The Relationship Between Relative Value Units and Outcomes: a Multivariate Analysis of Plastic Surgery Procedures

Eplasty. 2012  |  Pubmed ID: 23308307

Relative value units (RVUs) were developed as a quantifier of requisite training, knowledge, and technical expertise for performing various procedures. In select procedures, increasing RVUs have been shown to substitute well for increasing surgical complexity and have been linked to greater risk of complications. The relationship of RVU to outcomes has yet to be examined in the plastic surgery population.

Autologous Options for Postmastectomy Breast Reconstruction: a Comparison of Outcomes Based on the American College of Surgeons National Surgical Quality Improvement Program

Journal of the American College of Surgeons. Feb, 2013  |  Pubmed ID: 23211118

The postmastectomy patient faces a plethora of choices when opting for autologous breast reconstruction; however, multi-institutional data comparing the available techniques are lacking. The National Surgical Quality Improvement Program (NSQIP) database provides a robust patient cohort for comparing outcomes and determining independent predictors of complications for each autologous method.

A Multivariate Regression Analysis of Panniculectomy Outcomes: Does Plastic Surgery Training Matter?

Plastic and Reconstructive Surgery. Apr, 2013  |  Pubmed ID: 23542279

Panniculectomy can improve quality of life in morbidly obese patients, but its functional benefits are counterbalanced by relatively high complication rates. The authors endeavored to determine the impact of plastic surgery training on panniculectomy outcomes.

Breast Implant Procedures Under Conscious Sedation: a 6-year Experience in 461 Consecutive Patients

Plastic and Reconstructive Surgery. May, 2013  |  Pubmed ID: 23629098

Breast implant procedures are commonly performed using general anesthesia; however, patient apprehension, the potential for improved safety, lower costs, and faster recovery times have increased interest in the use of conscious sedation in plastic surgery. The authors examined the safety and efficacy of breast implant procedures performed under conscious sedation over a 6-year period using their standardized institutional protocol.

Reply: To PMID 23211118

Journal of the American College of Surgeons. Jul, 2013  |  Pubmed ID: 23791294

Reply: Breast Implant Procedures Under Conscious Sedation: a 6-year Experience in 461 Consecutive Patients

Plastic and Reconstructive Surgery. Nov, 2013  |  Pubmed ID: 24165642

Sentinel Lymph Node Biopsy Versus Axillary Lymphadenectomy in Patients Treated with Lumpectomy: an Analysis of Short-term Outcomes

Annals of Surgical Oncology. Jan, 2014  |  Pubmed ID: 24046110

Sentinel lymph node biopsy (SLNB) has been shown to reduce many of the long-term complications associated with a traditional axillary lymph node dissection (ALND); however, short-term outcomes have yet to be characterized. This study was designed to identify trends and differences in 30-day outcomes of partial mastectomy with concurrent SLNB or complete ALND to more effectively determine which patients may be at risk for perioperative complications.

Pediatric Plastic Surgery: Four-dimensional Medicine

Plastic Surgical Nursing : Official Journal of the American Society of Plastic and Reconstructive Surgical Nurses. Jan-Mar, 2014  |  Pubmed ID: 24583663

Pediatric plastic surgery is a very rewarding and challenging field. Many of our patients are managed longitudinally, often into adulthood, and deal with complex surgical problems. The role of an experienced nurse in outpatient plastic surgery is critical to managing these complex patients. The role of the pediatric plastic surgery nurse also includes coordination of care and detailed knowledge of patients and families to help direct the formation of individualized treatment plans. This role, though challenging, also allows nurses to form strong bonds with their patients and families and serve as a source of advocacy, support, and information.

Surgical Management of Velopharyngeal Insufficiency

Clinics in Plastic Surgery. Apr, 2014  |  Pubmed ID: 24607193

The primary goal of cleft palate repair is to create an anatomically and functionally intact palate while minimally affecting maxillary growth and development. In order to produce normal speech, a child must have velopharyngeal competence, defined as the ability to completely close the velopharyngeal sphincter that separates the oropharynx and nasopharynx. The absence of this ability, termed velopharyngeal insufficiency (VPI), is seen in a wide range of patients following primary cleft palate repair. This article discusses patient assessment, treatment options, and the surgical management of VPI. Recent trends and future directions in management are also presented.

Characterization of Living Skin Using Multi-view Stereo and Isogeometric Analysis

Acta Biomaterialia. Nov, 2014  |  Pubmed ID: 25016279

Skin is our interface with the outside world. In its natural environment, it displays unique mechanical characteristics, such as prestretch and growth. While there is a general agreement on the physiological importance of these features, they remain poorly characterized, mainly because they are difficult to access with standard laboratory techniques. Here we present a new, inexpensive technique to characterize living skin using multi-view stereo and isogeometric analysis. Based on easy-to-create hand-held camera images, we quantify prestretch, deformation and growth in a controlled porcine model of chronic skin expansion. Over a period of 5 weeks, we gradually inflate an implanted tissue expander, take weekly photographs of the experimental scene, reconstruct the geometry from a tattooed surface grid and create parametric representations of the skin surface. After 5 weeks of expansion, our method reveals an average area prestretch of 1.44, an average area stretch of 1.87 and an average area growth of 2.25. Area prestretch is maximal in the ventral region with a value of 2.37, whereas area stretch and area growth are maximal above the center of the expander, with values of 4.05 and 4.81, respectively. Our study has immediate impact on understanding living skin to optimize treatment planning and decision making in plastic and reconstructive surgery. Beyond these direct implications, our experimental design has broad applications in clinical research and basic sciences: it serves as a simple, robust, low cost, easy-to-use tool to reconstruct living membranes, which are difficult to characterize in a conventional laboratory setup.

Evidence-based Medicine: Orbital Floor Fractures

Plastic and Reconstructive Surgery. Dec, 2014  |  Pubmed ID: 25415098

After studying this article, the participant should be able to: 1. Explain the epidemiology, anatomy, and pathophysiology of orbital floor fractures. 2. Select the optimal timing of--and understand the indications for-operative repair of orbital floor fractures. 3. List advantages and disadvantages of the surgical approaches and materials available for orbital floor reconstruction. 4. Identify special considerations in treating pediatric patients presenting with orbital floor fractures.

Abstract 52: Mutating Fibroblast Growth Factor Receptor 1 (fgfr1) in Zebrafish to Create a New Model of Craniosynostosis

Plastic and Reconstructive Surgery. Mar, 2014  |  Pubmed ID: 25942163

Abstract 68: Identification of Twist Expression Patterns and Localized Manipulation of Fgfr1 Expression in Zebrafish Cranial Sutures

Plastic and Reconstructive Surgery. Mar, 2014  |  Pubmed ID: 25942179

Sternal "retraction": a Novel Application of a Mandibular Distractor in Treating Ectopia Cordis with Complete Cleft Sternum

Annals of Plastic Surgery. May, 2015  |  Pubmed ID: 24042213

Complete thoracic ectopia cordis is associated with a uniformly dismal prognosis. The primary challenges of this disorder are (1) returning the heart to the thoracic cavity, (2) stabilizing the chest wall, and (3) repairing the sternal defect. Previously published techniques for achieving these goals have demonstrated very limited success and/or significant morbidity.We present a novel application of a mandibular distraction device as part of staged repair of this historically challenging problem. This method uses immediate stabilization and gradual "retraction" of the sternal remnants, thereby allowing physiologic compensation and avoiding the cardiorespiratory embarrassment associated with returning the heart to the thoracic cavity. Moreover, this technique allows stabilization of the associated sternal cleft and chest wall without the commonly associated morbidity of the currently available techniques.

Multi-view Stereo Analysis Reveals Anisotropy of Prestrain, Deformation, and Growth in Living Skin

Biomechanics and Modeling in Mechanobiology. Oct, 2015  |  Pubmed ID: 25634600

Skin expansion delivers newly grown skin that maintains histological and mechanical features of the original tissue. Although it is the gold standard for cutaneous defect correction today, the underlying mechanisms remain poorly understood. Here we present a novel technique to quantify anisotropic prestrain, deformation, and growth in a porcine skin expansion model. Building on our recently proposed method, we combine two novel technologies, multi-view stereo and isogeometric analysis, to characterize skin kinematics: Upon explantation, a unit square retracts ex vivo to a square of average dimensions of [Formula: see text]. Upon expansion, the unit square deforms in vivo into a rectangle of average dimensions of [Formula: see text]. Deformations are larger parallel than perpendicular to the dorsal midline suggesting that skin responds anisotropically with smaller deformations along the skin tension lines. Upon expansion, the patch grows in vivo by [Formula: see text] with respect to the explanted, unexpanded state. Growth is larger parallel than perpendicular to the midline, suggesting that elevated stretch activates mechanotransduction pathways to stimulate tissue growth. The proposed method provides a powerful tool to characterize the kinematics of living skin. Our results shed light on the mechanobiology of skin and help us to better understand and optimize clinically relevant procedures in plastic and reconstructive surgery.

Targeted Muscle Reinnervation in the Upper Extremity Amputee: A Technical Roadmap

The Journal of Hand Surgery. Sep, 2015  |  Pubmed ID: 26314220

Targeted muscle reinnervation (TMR) offers the potential for improved prosthetic function by reclaiming the neural control information that is lost as a result of upper extremity amputation. In addition to the prosthetic control benefits, TMR is a potential treatment for postamputation neuroma pain. Here, we present our surgical technique for TMR nerve transfers in transhumeral and shoulder disarticulation patients.

Modeling Tissue Expansion with Isogeometric Analysis: Distinguishing True Skin Growth from Elastic Skin Stretch

Plastic and Reconstructive Surgery. Oct, 2015  |  Pubmed ID: 26397523

Aesthetic Uses of Neuromodulators: Current Uses and Future Directions

Plastic and Reconstructive Surgery. Nov, 2015  |  Pubmed ID: 26441114

The introduction of neuromodulators for aesthetic facial improvements greatly expanded the limits of nonsurgical facial rejuvenation. Although many current uses are considered "off-label," the widespread acceptance and favorable safety profile of properly used botulinum toxins have made them one of the most common aesthetic treatments available.

The Incompatibility of Living Systems: Characterizing Growth-Induced Incompatibilities in Expanded Skin

Annals of Biomedical Engineering. May, 2016  |  Pubmed ID: 26416721

Skin expansion is a common surgical technique to correct large cutaneous defects. Selecting a successful expansion protocol is solely based on the experience and personal preference of the operating surgeon. Skin expansion could be improved by predictive computational simulations. Towards this goal, we model skin expansion using the continuum framework of finite growth. This approach crucially relies on the concept of incompatible configurations. However, aside from the classical opening angle experiment, our current understanding of growth-induced incompatibilities remains rather vague. Here we visualize and characterize incompatibilities in living systems using skin expansion in a porcine model: We implanted and inflated two expanders, crescent, and spherical, and filled them to 225 cc throughout a period of 21 days. To quantify the residual strains developed during this period, we excised the expanded skin patches and subdivided them into smaller pieces. Skin growth averaged 1.17 times the original area for the spherical and 1.10 for the crescent expander, and displayed significant regional variations. When subdivided into smaller pieces, the grown skin patches retracted heterogeneously and confirmed the existence of incompatibilities. Understanding skin growth through mechanical stretch will allow surgeons to improve-and ultimately personalize-preoperative treatment planning in plastic and reconstructive surgery.

Overview of Botulinum Toxins for Aesthetic Uses

Clinics in Plastic Surgery. Jul, 2016  |  Pubmed ID: 27363760

Botulinum toxin type A (BTA) can be used for facial aesthetics. The 3 currently available BTA types include onabotulinumtoxinA (Botox; Botox Cosmetic, Allergan, Irvine, CA), abobotulinumtoxinA (Dysport; Ipsen, Ltd, Berkshire, UK), and incobotulinumtoxinA (Xeomin; Merz Pharmaceuticals, Frankfurt, Germany). The mechanism of action and clinical uses for treatment of dynamic lines of the forehead, brow, glabella, lateral orbit, nose, and lips are presented, as well as treatment of masseter hypertrophy, platysmal bands, and improvements of the perioral region. Specific BTA injection sites and suggested doses are presented.

Therapy and Rehabilitation for Upper Extremity Injuries in Athletes

Hand Clinics. Feb, 2017  |  Pubmed ID: 27886837

The approach to rehabilitation of upper extremity injuries in athletes differs from traditional rehabilitation protocols. In general, athletes have higher functional demands and wish to return to competitive sport in a timely manner. Comprehensive rehabilitation must therefore be balanced with a timely and safe return to sport. Several rehabilitation programs and adjunctive therapies are available to hasten convalescence while minimizing the athlete's risks of reinjury. Here, we review techniques for soft tissue mobilization and strength training in athletic populations. We also discuss orthotics, taping, and alternative therapies used in rehabilitation and evaluate the evidence in support of these modalities.

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