International Guest Scholar: Paving the way from reconstructive to regenerative surgery

Plastic surgeons treat many complex wounds that require soft tissue reconstruction, such as diabetic foot ulcers, postoperative breast reconstruction, severe infection, and reconstruction after major trauma. Traditionally, structural defects rely on replacement with autologous tissue or allogeneic materials. Although a certain degree of success has been achieved, the final outcome has rarely been ideal.

In recent years, developments in regenerative medicine have provided new opportunities for more effective care. The essential part of regenerative medicine is tissue engineering, defined as the application of engineering and life science principles and methods toward the development of biological substitutes in order to restore, maintain, or improve the function of biological tissue.*

It was my great honor to be the 2016 Elias Hanna International Guest Scholar. With the support of this American College of Surgeons (ACS) scholarship, I also had the privilege of visiting Stanford University, CA, and the University of Chicago, IL, before going to Washington, DC, for Clinical Congress 2016. The trip was focused on understanding the impact regenerative medicine may have on the practice of plastic surgery in the future, particularly with respect to wound healing and breast reconstruction.

Stanford University

Dr. Cheng (right) and Dr. Gurtner at Stanford University

Dr. Cheng (right) and Dr. Gurtner at Stanford University

My first stop was Stanford University. My host was Geoffrey Gurtner, MD, FACS, Johnson & Johnson Professor of Surgery and professor of surgery and bioengineering. Dr. Gurtner has conducted many important studies in wound healing, with a focus on the interaction of tissue regeneration and fibrosis pathways during wound healing subsequent to skin injury. I had the opportunity to speak with the members of his research team and to attend the lab meeting.

The laboratory is equipped with state-of-the-art instruments for a variety of wound healing studies, and research topics include biomedical engineering, molecular biology, cytology, animal assays, drug release, genetic engineering, and tissue rejection reactions. Dr. Gurtner explained how he uses time management, delegation, and collaboration strategies to conduct high-quality research while still performing clinical work.

Because I, too, have done considerable research on regenerative medicine for wound healing, Dr. Gurtner invited me to speak at the plastic surgery grand rounds. I had a nice discussion with some senior physicians in the audience after the presentation, including Michael Longaker, MD, FACS, who also specializes in wound healing research.

I visited Dr. Gurtner’s clinic at the Stanford Advanced Wound Care Center, Redwood City, CA. In addition to plastic surgeons, the center hires physicians who specialize in metabolic diseases, cardiovascular surgery, rehabilitation, and infectious disease. The center is equipped with two hyperbaric oxygen chambers, along with other resources for providing state-of-the-art wound care.

Dr. Gurtner has conducted several clinical trials aimed at promoting the application of regenerative medicine principles in the treatment of chronic wounds, including the use of amniotic membrane products with live cells to enhance the healing of chronic wounds. With the increase in the elderly population globally, the incidence of diabetic ulcers, bed sores, and lower extremity arterial ulcers is expected to rise in the future, creating a great challenge for the medical care and social supportive systems. Therefore, a wound care center equipped with hyperbaric oxygen therapy and other cutting-edge wound care facilities is necessary to provide a full range of treatment options to patients with chronic wounds.

University of Chicago

Dr. Cheng with Dr. Song at the University of Chicago

Dr. Cheng with Dr. Song at the University of Chicago

My next stop was the University of Chicago, where I met with my host David Song, MD, FACS, chief of plastic surgery. Dr. Song is an internationally recognized expert in breast reconstruction surgery and is the immediate past-president of the American Society of Plastic Surgeons. The incidence of breast cancer continues to rise in many countries, and consequently, the demand for breast reconstruction has increased. For women, breast reconstruction can significantly reduce the psychological trauma of patients after mastectomy. Breast reconstruction is now a mature technique with multiple approaches, including prosthesis and autologous tissue transfer. Although artificial implant is still the most common form of breast reconstruction, autologous tissue reconstruction generally is considered to yield better aesthetic results.

Dr. Song specializes in several methods of autologous breast reconstruction, including deep inferior epigastric perforator flap, superior gluteal artery perforator flap, superficial inferior epigastric artery flap, epigastric artery flap, and thoracodorsal artery perforator flap. I had the privilege of observing Dr. Song as he performed some of these operations and learned quite a few surgical techniques. Dr. Song has conducted several clinical trials related to chest wall reconstruction, breast tumor resection, and breast reconstruction.

During my visit, I also participated in clinical teaching activities, such as journal club, and I had a chance to interact with residents, fellows, and the faculty regarding debated issues in wound care and breast reconstruction.

In a conversation with Dr. Song, he acknowledged the value of autologous fat transplantation for breast reconstruction and said he believes that adipose tissue-related technologies and products represent an important adjunct in breast reconstruction. Autologous fat grafts have been used for more than 100 years in plastic and reconstructive surgery. The early autologous fat transplant procedures had a high incidence of complications, such as infection, fat resorption, fat necrosis, and calcification. With improvements in liposuction, including refined procedures of purification, separation, and injection, autologous fat transplantation has become a reliable cosmetic and reconstructive surgical technique. The most common application is treating the facial defects caused by trauma or subcutaneous fat atrophy.

Whereas excessive adipose tissue can frequently be found in the abdomen or other parts of the body, it is usually possible to harvest enough fat for transfer with minimal donor site morbidity. Consequently, its application in the treatment of breast defects has flourished in recent years. In particular, recent studies have shown that adipose tissue contains a large amount of mesenchymal stem cells, which are a valuable cell source for regenerative medicine or tissue engineering. Cell-assisted lipotransfer, as described by Prof. Takaro Yoshimura from Japan, depicted a procedure that separates adipose-derived stem cells from adipose tissue and mixes them with fat to increase the concentration of stem cells within fat, thus increasing the survival and regeneration of the transplanted fat. However, the machine that can separate adipose stem cells from fat extracts has not yet been approved in the U.S. and is therefore unavailable at most hospitals, including the University of Chicago.

Clinical Congress

Clinical Congress 2016: Dr. Cheng receiving the International Guest Scholar award from Guiseppe R. Nigri, MD, FACS, Chair, ACS Scholarships Committee

Clinical Congress 2016: Dr. Cheng receiving the International Guest Scholar award from Guiseppe R. Nigri, MD, FACS, Chair, ACS Scholarships Committee

As the highlight of my visit, I traveled to Washington, DC, to attend the ACS Clinical Congress 2016. Since my residency, I have met several Honorary Fellows of the ACS, so I was excited to have the opportunity to attend Clinical Congress. The scale of the conference and the variety of educational sessions were amazing.

I appreciated the opportunity to attend a few scientific sessions for free. Maurice Nahabedian, MD, FACS, professor of plastic surgery, Georgetown University, Washington, DC, delivered a comprehensive overview on breast reconstruction at the session Atypical Breast Lesions: Defining and Managing this High Risk Population. After the session, I discussed with Dr. Nahabedian his surgical technique of complete coverage of prosthesis with artificial dermis in implant-based reconstruction.

Another session, Wound Care: Mentoring the Mentors, also was helpful for me. The speakers covered a range of wound care issues, including infection control, negative pressure wound therapy, nutrition support, and choice of dressings.

Thanks to the arrangement of the ACS International Relations Committee (IRC), International Guest Scholars from various countries had a chance to meet on several occasions, including the welcome reception and luncheon. We were invited to participate in the Opening Ceremony and the Annual Meeting of the IRC. I appreciated the prospect of the ACS extending its reach beyond North America and promoting communication among the surgical communities around the world. Global outreach will benefit not only the ACS, but also surgeons and surgical patients worldwide.

At a session for all of the IGS recipients, I was impressed by the diversity of the background of the scholars, ranging from basic research and clinical medicine, to surgical education and humanitarian aid. I gave a speech titled Paving the Way from Reconstructive Surgery to Regenerative Surgery. The concept of promoting tissue regeneration with bioactive scaffolds or cell therapy has captured the attention of the plastic and reconstructive surgery community. However, transplanting isolated adipose-derived stem cells into injured tissue often results in early cell death with limited therapeutic effects. Our study explored the use of cell sheet technology, which can exhibit excellent biological properties, resulting in enhanced wound healing and tissue regeneration.

Striking a balance between cost and quality

I was impressed with the quality of the medical services at Stanford University and the University of Chicago. The operating rooms housed all kinds of advanced equipment and devices. For example, feather sutures, which are used only for endoscopic or cosmetic operations in Taiwan, are used at these U.S. institutions for general skin closure. In the outpatient clinic, physicians have plenty of time to communicate with patients and their caregivers. However, high quality results in high medical expenses in the U.S., rendering medical insurance unaffordable for low-income Americans. These complex health care issues are being debated in many countries around the world.

For example, my research topic of applying adult stem cells in regenerative medicine and tissue repair will be an expensive treatment modality. Striking a balance between developing cutting-edge medical technologies and making them affordable for most people will be a challenge.

I would like to thank the ACS again for the award and the opportunity to attend the Clinical Congress. I believe the research done in the laboratory will eventually lead us to achieve the clinical application of regenerative medicine in wound healing and breast reconstruction.

*Langer R, Vacanti JP. Tissue engineering. Science. 1993;260(5110):920-926.


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