Roger Khouri - Academia.edu (original) (raw)

Papers by Roger Khouri

Research paper thumbnail of Fat Grafting in Breast Augmentation

Research paper thumbnail of Large Volume Fat Grafting

Research paper thumbnail of Free Flap Coverage Of The Hand

Clinics in Plastic Surgery, 1997

Microvascular free tissue transfer has been a major advancement in the treatment of soft-tissue d... more Microvascular free tissue transfer has been a major advancement in the treatment of soft-tissue defects of the hand. Free tissue transfers have expanded our options and have altered our approach to hand defects. It is no longer satisfactory to cover hand wounds with unsightly, bulky flaps of tissue. Microsurgical free tissue transfers have given us the tools for more refinement in hand soft-tissue reconstruction and have changed the standards for a successful outcome.

Research paper thumbnail of Principles of Flap Prefabrication

Clinics in Plastic Surgery, 1992

Clinical flap prefabrication can be classified according to the basic technique of plastic surger... more Clinical flap prefabrication can be classified according to the basic technique of plastic surgery used for the prefabrication. There are currently three methods: (1) delay or expansion; (2) grafting; and (3) vascular induction by staged transfer. Illustrative cases are given to point out the advantages and indications for each method. A fourth, still experimental, method is based on cell biology advances that are looming on the horizon and may have revolutionary future clinical applications.

Research paper thumbnail of Commentary on: Power-Assisted Liposuction and Lipofilling: Techniques and Experience in Large-Volume Fat Grafting

Aesthetic Surgery Journal, 2019

Plastic surgery owes its name to the Greek word "plastikos," meaning to give shape. Autologous fa... more Plastic surgery owes its name to the Greek word "plastikos," meaning to give shape. Autologous fat transfer (AFT) got us closer to this original endeavor. Fat injections enabled us to enlarge tissues without implants or flap transfers. But reliability remained an issue. We soon realized that to be successful, tissue augmentation required more than just filling the recipient tissues with fat. The extracellular fibrovascular scaffold, a major determinant of soft-tissue size and shape, also had to be addressed. For the tissues to get larger, their fibrous scaffold has to stretch, expand, or loosen to accommodate the new size and shape. Syd Coleman with his microdroplet grafting was the first to demonstrate the reliability of fat transfer. 1 He also realized that in order to accommodate the graft, the recipient tissue had to be loosened by extensive to-andfro passages of his blunt-tipped grafting cannula. It took him thousands of multidirectional passes with a 1-mL syringe to deliver 100 mL of fat. This painstaking multipass micrografting was key to his success. But there was only so much the recipient area could accommodate, and tissue augmentation was still limited. To that effect, we introduced external vacuum expansion (EVE) as a nontraumatic way to enlarge the fibrous scaffold and improve its vascularity. 2,3 However, despite its multiple advantages, EVE had its limitations. After watching Gino Rigotti perform his percutaneous needle release, we coined the term "rigottomy," a very useful means of releasing the tougher fibers resistant to EVE. 4 This opened the concept of mesh expansion, a process that turns a restrictive cicatrix into a larger recipient matrix for fat grafting. 4,5 We later built on this to develop

Research paper thumbnail of Autologous Fat Transfer After Augmentation and Reconstruction of the Female Breast: An International, Cross-Sectional Photo-Comparison Study Among Different Physician and Laymen Study Groups

Surgical innovation, Jan 10, 2018

The aim of this study is to compare the cosmetic evaluation of autologous fat transfer (AFT) for ... more The aim of this study is to compare the cosmetic evaluation of autologous fat transfer (AFT) for various indications between surgeons and different laymen groups. Despite the upsurge in AFT scientific/clinical interest, objectifying satisfaction has only recently progressed beyond simple Likert-type/Visual Analog Scales. Furthermore, differences in satisfaction between laymen and surgeons has not been thoroughly studied. A photo comparison study between European plastic surgeons and different laymen groups was conducted to investigate agreement on cosmetic evaluation of AFT. Three sets of preoperative/postoperative photographs illustrating patients treated with External Vacuum Expansion (EVE) + AFT for various indications in breast surgery were scored according to the Harris Scale, and the interrater agreement was analyzed using Cohen's κ. The overall agreement between the surgeons and the groups of former augmentation, control group, and deep inferior epigastric artery perforat...

Research paper thumbnail of Current Clinical Applications of Fat Grafting

Plastic & Reconstructive Surgery, 2017

he results are amazing but inconsistent." This was the sentiment surrounding free flaps in the 19... more he results are amazing but inconsistent." This was the sentiment surrounding free flaps in the 1980s. We discovered a naturally occurring inhibitor of coagulation that prevented anastomotic thrombosis in the laboratory 1 and conducted a double-blinded, controlled, randomized study to assess its benefit in free flaps. Disappointingly, there was no significant effect. 2 When we dissected why free flaps fail, we realized that success depended on multiple factors chain-linked in series, and that the anastomosis was not always the weakest link. 3 Free flaps became a reliable procedure when we abandoned the search for a panacea and realized that success required exacting surgical technique. This history illustrates the concept that, in a multivariable process, optimizing a single variable does not necessarily improve the outcome; the entire process must be taken into consideration. Similarly, autologous fat transfer has opened many applications in reconstructive surgery with amazing results, but many dismiss it as inconsistent. Although many individual technical factors have been singled out as being responsible for graft take, it has become clear that no single additive or processing method can serve as a panacea. 4-11 Favorable results can be consistently obtained by following established principles and techniques. Fat graft surgery should be approached with the same degree of craftsmanship as microvascular free flap surgery. 12,13 This article reviews the established principles of fat graft survival, elaborates on the surgical techniques that adhere to these principles, and provides an overview of the clinical applications. PRINCIPLES OF GRAFT SURVIVAL What Is Fat? Over 90 percent of adipose tissue volume consists of adipocytes, but nearly 50 percent of the in vivo adipose tissue total cell number consists of adipose-derived stem cells, fibroblasts, endothelial cells, and pericytes in an extracellular matrix. 14 Although fat was initially thought to be an inert substance for energy storage, recent research has elicited its regenerative capabilities. Many studies have demonstrated the regenerative potential of autologous fat transfer, presumably because of its adipose-derived stem cell content. This includes angiogenesis, 15 peripheral nerve regeneration, 16 enhancement of dermal thickness and elasticity, 17 reversal of fibrosis (secondary to radiation therapy, 18,19 scarring, 20 Disclosure: Roger K. Khouri has equity interest in LipoCosm, the manufacturer of the LipoGrafter. He is the inventor of Brava, the original External Vacuum Expander, but he no longer has any financial interest in Brava, LLC. Roger K. Khouri Jr. has no conflicts of interest to disclose.

Research paper thumbnail of Method and device for use in minimally invasive approximation of muscle and other tissue

Research paper thumbnail of Method and System for Preparing Soft Tissue for Grafting, Enhancing Grafting Results, and Grafting Autologous Fat and Adipocyte Derived Stem Cells to Soft Tissue Such as the Breast and Other Tissue Defects

Research paper thumbnail of Commentary on: Prospective 1-Year Follow-Up Study of Breast Augmentation by Cell-Assisted Lipotransfer

Aesthetic Surgery Journal, 2015

Research paper thumbnail of Reply: megavolume autologous fat transfer: part I. Theory and principles

Plastic and reconstructive surgery, 2014

This article describes the theory and principles behind the authors' success in megavolume (250-m... more This article describes the theory and principles behind the authors' success in megavolume (250-ml range) autologous fat transfer to the breasts. When large volumes are grafted into a tight space, the interstitial fluid pressure increases to impair capillary blood flow and the crowded graft droplets coalesce into lakes, with poor graft-to-recipient interface. These factors have historically restricted the volume of fat that can be grafted into small recipient breasts. The decreased interface increases the distance oxygen must diffuse to reach the grafted adipocytes, causing central necrosis to occur before neovascularization. The increased interstitial fluid pressure reduces capillary radius, reducing oxygen delivery to grafted adipose tissue. The Brava external expansion device harnesses the regenerative capabilities of mechanical forces to preoperatively increase the volume and vascularity of the recipient site, allowing megavolumes of fat to be grafted diffusely without significantly decreasing graft-to-recipient interface or increasing interstitial fluid pressure. The application of these principles has allowed the authors to successfully graft megavolumes of fat into the breasts of over 1000 patients with substantial long-term retention.

Research paper thumbnail of Prefabrication of Composite Free Flaps Through Staged Microvascular Transfer

Plastic and Reconstructive Surgery, 1991

Research paper thumbnail of The Expanded Scapular Flap

Plastic and Reconstructive Surgery, 1995

The scapular fasciocutaneous flap is a very reliable free tissue transfer, but its size and/or th... more The scapular fasciocutaneous flap is a very reliable free tissue transfer, but its size and/or thickness may limit its use in some patients. Scapular fasciocutaneous flaps were expanded for 6 to 12 weeks prior to transfer in 14 patients. The flaps ranged in size from 96 to 1885 cm2 and were used to cover chronic soft-tissue defects. Twelve were transferred as free flaps to distant sites, while two were transferred as pedicled flaps to the ipsilateral extremity. The pedicled flaps were designed across the entire back to incorporate both scapular territories but were rotated on a single vascular pedicle. All flaps survived, but three had marginal distal necrosis not related to the microvascular anastomoses. Two flaps transferred by microsurgical technique developed arterial thromboses requiring revision of the anastomoses. Three patients developed partial donor wound dehiscence after transfer of large flaps that healed by secondary intention in two cases and required a split-thickness skin graft for donor-site closure in the third. Flap expansion produces a delay phenomenon that augments blood supply and increases the area of skin that can survive on a single vascular pedicle. This technique may be useful in selected patients in whom a large, thin fasciocutaneous flap is required and there is sufficient time to allow flap expansion prior to transfer.

Research paper thumbnail of Refinements in hand coverage with microvascular free flaps

Plastic and Reconstructive Surgery, 1994

Research paper thumbnail of Metacarpal Synostosis: A Simple Classification and a New Treatment Technique

Plastic and Reconstructive Surgery, 2001

Research paper thumbnail of Free Flaps as Flow-Through Vascular Conduits for Simultaneous Coverage and Revascularization of the Hand or Digit

Plastic and Reconstructive Surgery, 1996

Research paper thumbnail of Distraction Lengthening for the Congenitally Short Metatarsal: A Case Report

Foot & Ankle, 1989

Distraction lengthening has gained wide acceptance in general orthopedics and in upper extremity ... more Distraction lengthening has gained wide acceptance in general orthopedics and in upper extremity reconstructions. The application of this technique to the foot is presented. The congenitally short fourth metatarsal of a 16-yr-old girl was successfully lengthened by a two-stage procedure. At the first stage, an open diaphyseal osteotomy was performed and the distraction apparatus was secured. Over the ensuing 5 weeks, 36 mm of distraction was achieved. At the second stage, the distracted gap was filled with a fibular bone graft. Following uncomplicated healing, there was no gait, intrinsic muscle, or tendon abnormalities. Metatarsal distraction lengthening can be safely accomplished provided there is good bone stock, adequate soft tissue, and a cooperative patient.

Research paper thumbnail of Bilateral Lower Limb Salvage with Free Flaps in a Patient with Sickle Cell Ulcers

Annals of Plastic Surgery, 1991

Research paper thumbnail of Cartilage Engineered in Predetermined Shapes Employing Cell Transplantation on Synthetic Biodegradable Polymers

Plastic And Reconstructive Surgery, 1994

Research paper thumbnail of Commentary on: Safety and Effectiveness of Single Session Mega Volume Fat Grafting for Breast Augmentation: A Space Creating Concept and Clinical Experiences

Aesthetic Surgery Journal

Research paper thumbnail of Fat Grafting in Breast Augmentation

Research paper thumbnail of Large Volume Fat Grafting

Research paper thumbnail of Free Flap Coverage Of The Hand

Clinics in Plastic Surgery, 1997

Microvascular free tissue transfer has been a major advancement in the treatment of soft-tissue d... more Microvascular free tissue transfer has been a major advancement in the treatment of soft-tissue defects of the hand. Free tissue transfers have expanded our options and have altered our approach to hand defects. It is no longer satisfactory to cover hand wounds with unsightly, bulky flaps of tissue. Microsurgical free tissue transfers have given us the tools for more refinement in hand soft-tissue reconstruction and have changed the standards for a successful outcome.

Research paper thumbnail of Principles of Flap Prefabrication

Clinics in Plastic Surgery, 1992

Clinical flap prefabrication can be classified according to the basic technique of plastic surger... more Clinical flap prefabrication can be classified according to the basic technique of plastic surgery used for the prefabrication. There are currently three methods: (1) delay or expansion; (2) grafting; and (3) vascular induction by staged transfer. Illustrative cases are given to point out the advantages and indications for each method. A fourth, still experimental, method is based on cell biology advances that are looming on the horizon and may have revolutionary future clinical applications.

Research paper thumbnail of Commentary on: Power-Assisted Liposuction and Lipofilling: Techniques and Experience in Large-Volume Fat Grafting

Aesthetic Surgery Journal, 2019

Plastic surgery owes its name to the Greek word "plastikos," meaning to give shape. Autologous fa... more Plastic surgery owes its name to the Greek word "plastikos," meaning to give shape. Autologous fat transfer (AFT) got us closer to this original endeavor. Fat injections enabled us to enlarge tissues without implants or flap transfers. But reliability remained an issue. We soon realized that to be successful, tissue augmentation required more than just filling the recipient tissues with fat. The extracellular fibrovascular scaffold, a major determinant of soft-tissue size and shape, also had to be addressed. For the tissues to get larger, their fibrous scaffold has to stretch, expand, or loosen to accommodate the new size and shape. Syd Coleman with his microdroplet grafting was the first to demonstrate the reliability of fat transfer. 1 He also realized that in order to accommodate the graft, the recipient tissue had to be loosened by extensive to-andfro passages of his blunt-tipped grafting cannula. It took him thousands of multidirectional passes with a 1-mL syringe to deliver 100 mL of fat. This painstaking multipass micrografting was key to his success. But there was only so much the recipient area could accommodate, and tissue augmentation was still limited. To that effect, we introduced external vacuum expansion (EVE) as a nontraumatic way to enlarge the fibrous scaffold and improve its vascularity. 2,3 However, despite its multiple advantages, EVE had its limitations. After watching Gino Rigotti perform his percutaneous needle release, we coined the term "rigottomy," a very useful means of releasing the tougher fibers resistant to EVE. 4 This opened the concept of mesh expansion, a process that turns a restrictive cicatrix into a larger recipient matrix for fat grafting. 4,5 We later built on this to develop

Research paper thumbnail of Autologous Fat Transfer After Augmentation and Reconstruction of the Female Breast: An International, Cross-Sectional Photo-Comparison Study Among Different Physician and Laymen Study Groups

Surgical innovation, Jan 10, 2018

The aim of this study is to compare the cosmetic evaluation of autologous fat transfer (AFT) for ... more The aim of this study is to compare the cosmetic evaluation of autologous fat transfer (AFT) for various indications between surgeons and different laymen groups. Despite the upsurge in AFT scientific/clinical interest, objectifying satisfaction has only recently progressed beyond simple Likert-type/Visual Analog Scales. Furthermore, differences in satisfaction between laymen and surgeons has not been thoroughly studied. A photo comparison study between European plastic surgeons and different laymen groups was conducted to investigate agreement on cosmetic evaluation of AFT. Three sets of preoperative/postoperative photographs illustrating patients treated with External Vacuum Expansion (EVE) + AFT for various indications in breast surgery were scored according to the Harris Scale, and the interrater agreement was analyzed using Cohen's κ. The overall agreement between the surgeons and the groups of former augmentation, control group, and deep inferior epigastric artery perforat...

Research paper thumbnail of Current Clinical Applications of Fat Grafting

Plastic & Reconstructive Surgery, 2017

he results are amazing but inconsistent." This was the sentiment surrounding free flaps in the 19... more he results are amazing but inconsistent." This was the sentiment surrounding free flaps in the 1980s. We discovered a naturally occurring inhibitor of coagulation that prevented anastomotic thrombosis in the laboratory 1 and conducted a double-blinded, controlled, randomized study to assess its benefit in free flaps. Disappointingly, there was no significant effect. 2 When we dissected why free flaps fail, we realized that success depended on multiple factors chain-linked in series, and that the anastomosis was not always the weakest link. 3 Free flaps became a reliable procedure when we abandoned the search for a panacea and realized that success required exacting surgical technique. This history illustrates the concept that, in a multivariable process, optimizing a single variable does not necessarily improve the outcome; the entire process must be taken into consideration. Similarly, autologous fat transfer has opened many applications in reconstructive surgery with amazing results, but many dismiss it as inconsistent. Although many individual technical factors have been singled out as being responsible for graft take, it has become clear that no single additive or processing method can serve as a panacea. 4-11 Favorable results can be consistently obtained by following established principles and techniques. Fat graft surgery should be approached with the same degree of craftsmanship as microvascular free flap surgery. 12,13 This article reviews the established principles of fat graft survival, elaborates on the surgical techniques that adhere to these principles, and provides an overview of the clinical applications. PRINCIPLES OF GRAFT SURVIVAL What Is Fat? Over 90 percent of adipose tissue volume consists of adipocytes, but nearly 50 percent of the in vivo adipose tissue total cell number consists of adipose-derived stem cells, fibroblasts, endothelial cells, and pericytes in an extracellular matrix. 14 Although fat was initially thought to be an inert substance for energy storage, recent research has elicited its regenerative capabilities. Many studies have demonstrated the regenerative potential of autologous fat transfer, presumably because of its adipose-derived stem cell content. This includes angiogenesis, 15 peripheral nerve regeneration, 16 enhancement of dermal thickness and elasticity, 17 reversal of fibrosis (secondary to radiation therapy, 18,19 scarring, 20 Disclosure: Roger K. Khouri has equity interest in LipoCosm, the manufacturer of the LipoGrafter. He is the inventor of Brava, the original External Vacuum Expander, but he no longer has any financial interest in Brava, LLC. Roger K. Khouri Jr. has no conflicts of interest to disclose.

Research paper thumbnail of Method and device for use in minimally invasive approximation of muscle and other tissue

Research paper thumbnail of Method and System for Preparing Soft Tissue for Grafting, Enhancing Grafting Results, and Grafting Autologous Fat and Adipocyte Derived Stem Cells to Soft Tissue Such as the Breast and Other Tissue Defects

Research paper thumbnail of Commentary on: Prospective 1-Year Follow-Up Study of Breast Augmentation by Cell-Assisted Lipotransfer

Aesthetic Surgery Journal, 2015

Research paper thumbnail of Reply: megavolume autologous fat transfer: part I. Theory and principles

Plastic and reconstructive surgery, 2014

This article describes the theory and principles behind the authors' success in megavolume (250-m... more This article describes the theory and principles behind the authors' success in megavolume (250-ml range) autologous fat transfer to the breasts. When large volumes are grafted into a tight space, the interstitial fluid pressure increases to impair capillary blood flow and the crowded graft droplets coalesce into lakes, with poor graft-to-recipient interface. These factors have historically restricted the volume of fat that can be grafted into small recipient breasts. The decreased interface increases the distance oxygen must diffuse to reach the grafted adipocytes, causing central necrosis to occur before neovascularization. The increased interstitial fluid pressure reduces capillary radius, reducing oxygen delivery to grafted adipose tissue. The Brava external expansion device harnesses the regenerative capabilities of mechanical forces to preoperatively increase the volume and vascularity of the recipient site, allowing megavolumes of fat to be grafted diffusely without significantly decreasing graft-to-recipient interface or increasing interstitial fluid pressure. The application of these principles has allowed the authors to successfully graft megavolumes of fat into the breasts of over 1000 patients with substantial long-term retention.

Research paper thumbnail of Prefabrication of Composite Free Flaps Through Staged Microvascular Transfer

Plastic and Reconstructive Surgery, 1991

Research paper thumbnail of The Expanded Scapular Flap

Plastic and Reconstructive Surgery, 1995

The scapular fasciocutaneous flap is a very reliable free tissue transfer, but its size and/or th... more The scapular fasciocutaneous flap is a very reliable free tissue transfer, but its size and/or thickness may limit its use in some patients. Scapular fasciocutaneous flaps were expanded for 6 to 12 weeks prior to transfer in 14 patients. The flaps ranged in size from 96 to 1885 cm2 and were used to cover chronic soft-tissue defects. Twelve were transferred as free flaps to distant sites, while two were transferred as pedicled flaps to the ipsilateral extremity. The pedicled flaps were designed across the entire back to incorporate both scapular territories but were rotated on a single vascular pedicle. All flaps survived, but three had marginal distal necrosis not related to the microvascular anastomoses. Two flaps transferred by microsurgical technique developed arterial thromboses requiring revision of the anastomoses. Three patients developed partial donor wound dehiscence after transfer of large flaps that healed by secondary intention in two cases and required a split-thickness skin graft for donor-site closure in the third. Flap expansion produces a delay phenomenon that augments blood supply and increases the area of skin that can survive on a single vascular pedicle. This technique may be useful in selected patients in whom a large, thin fasciocutaneous flap is required and there is sufficient time to allow flap expansion prior to transfer.

Research paper thumbnail of Refinements in hand coverage with microvascular free flaps

Plastic and Reconstructive Surgery, 1994

Research paper thumbnail of Metacarpal Synostosis: A Simple Classification and a New Treatment Technique

Plastic and Reconstructive Surgery, 2001

Research paper thumbnail of Free Flaps as Flow-Through Vascular Conduits for Simultaneous Coverage and Revascularization of the Hand or Digit

Plastic and Reconstructive Surgery, 1996

Research paper thumbnail of Distraction Lengthening for the Congenitally Short Metatarsal: A Case Report

Foot & Ankle, 1989

Distraction lengthening has gained wide acceptance in general orthopedics and in upper extremity ... more Distraction lengthening has gained wide acceptance in general orthopedics and in upper extremity reconstructions. The application of this technique to the foot is presented. The congenitally short fourth metatarsal of a 16-yr-old girl was successfully lengthened by a two-stage procedure. At the first stage, an open diaphyseal osteotomy was performed and the distraction apparatus was secured. Over the ensuing 5 weeks, 36 mm of distraction was achieved. At the second stage, the distracted gap was filled with a fibular bone graft. Following uncomplicated healing, there was no gait, intrinsic muscle, or tendon abnormalities. Metatarsal distraction lengthening can be safely accomplished provided there is good bone stock, adequate soft tissue, and a cooperative patient.

Research paper thumbnail of Bilateral Lower Limb Salvage with Free Flaps in a Patient with Sickle Cell Ulcers

Annals of Plastic Surgery, 1991

Research paper thumbnail of Cartilage Engineered in Predetermined Shapes Employing Cell Transplantation on Synthetic Biodegradable Polymers

Plastic And Reconstructive Surgery, 1994

Research paper thumbnail of Commentary on: Safety and Effectiveness of Single Session Mega Volume Fat Grafting for Breast Augmentation: A Space Creating Concept and Clinical Experiences

Aesthetic Surgery Journal