Regenerative Medicine in Facial Plastic and Reconstructive Surgery: A Review

Stem Cell Aging and Regenerative Medicine

Stem cells are a promising source for regenerative medicine to cure a plethora of diseases that are currently treated based on either palliative or symptomatic relief or by preventing their onset and progression. Aging-associated degenerative changes in stem cells, stem cell niches, and signaling pathways bring a step by step decline in the regenerative and functional potential of tissues. Clinical studies and experiments on model organisms have pointed out checkpoints that aging will inevitably impose on stem cell aiming for transplantation and hence questions are raised about the age of the donor. In the following discourse, we review the fundamental molecular pathways that are implicated in stem cell aging and the current progress in tissue engineering and transplantation of each type of stem cells in regenerative medicine. We further focus on the consequences of stem cell aging on their clinical uses and the development of novel strategies to bypass those pitfalls and improve tissue replenishment.

Dental Mesenchymal Stem Cell-Based Translational Regenerative Dentistry: From Artificial to Biological Replacement

Dentistry is a continuously changing field that has witnessed much advancement in the past century. Prosthodontics is that branch of dentistry that deals with replacing missing teeth using either fixed or removable appliances in an attempt to simulate natural tooth function. Although such "replacement therapies" appear to be easy and economic they fall short of ever coming close to their natural counterparts. Complications that arise often lead to failures and frequent repairs of such devices which seldom allow true physiological function of dental and oral-maxillofacial tissues. Such factors can critically affect the quality of life of an individual. The market for dental implants is continuously growing with huge economic revenues. Unfortunately, such treatments are again associated with frequent problems such as peri-implantitis resulting in an eventual loss or replacement of implants. This is particularly influential for patients having co-morbid diseases such as diabetes or osteoporosis and in association with smoking and other conditions that undoubtedly affect the final treatment outcome. The advent of tissue engineering and regenerative medicine therapies along with the enormous strides taken in their associated interdisciplinary fields such as stem cell therapy, biomaterial development, and others may open arenas to enhancing tissue regeneration via designing and construction of patient-specific biological and/or biomimetic substitutes. This review will overview current strategies in regenerative dentistry while overviewing key roles of dental mesenchymal stem cells particularly those of the dental pulp, until paving the way to precision/translational regenerative medicine therapies for future clinical use.

Cranioplasty Using a Mixture of Biologic and Nonbiologic Agents

Importance

A surgeon faces challenges with cranioplasty techniques to achieve a successful result with relatively few complications.

Objective

To describe a unique technique for incorporating both biologic autologous bone and nonbiologic allograft materials for defect coverage in cranioplasty with favorable outcomes and low occurrence of complications.

Design, Setting, and Participants

A retrospective medical records review of all 26 patients who underwent primary cranioplasty procedure with a modified technique between January 2011 and December 2015 at a high-volume head and neck oncologic reconstructive practice was conducted; data analysis was also performed during that period. After several years of experience with traditional cranioplasty maneuvers, the modified technique has evolved to incorporate both autologous bone grafts and alloplastic materials in the formation of a shapeable on-lay material. Data were collected on demographics, need for cranioplasty, materials used, outcomes, and risk factors.

Main Outcomes and Measures

Rates of infection, hematoma, flap loss or resorption, cerebrospinal fluid leak, hardware exposure or malfunction, and repeated reconstruction.

Results

Of the 26 patients, 21 (81%) were men; mean (SD) age was 65.8 (14.3) years. Eight (31%) patients had a history of diabetes, 4 (15%) patients were receiving immunosuppressive drugs, and 5 (19%) patients were active smokers at the time of surgery. Neoplasia was the most common cause of the calvarial defect seen, responsible for 20 of 28 (71%) operative defects and necessitated procedures. All but 1 patient achieved successful mineralization following primary cranioplasty with the modified technique; this success was verified based on physical examination and follow-up imaging. Complications were rare and involved only 3 patients who developed postoperative infection; 1 (4%) of these patients lost the integrity of the cranioplasty. Thus, the rate of infection was 11% and loss rate was 4%. Preoperative and postoperative radiotherapy appeared to have no bearing on graft survival.

Conclusions and Relevance

The results using a unique technique for incorporating both biologic autologous bone and nonbiologic allograft materials for defect coverage in cranioplasty are favorable, with satisfactory aesthetic outcomes and limited postoperative complications.

Level of Evidence

4.

Trends in Surgical Research in Head and Neck Cancer

OPINION STATEMENT

The task of surgical research is to improve the efficacy of available surgical therapeutic modalities, develop new ones, and balance this well with favorable functional outcome. Therefore, surgical research is composed of a translational and a clinical component. In translational surgical research, animal models are used to better understand the biology of head and neck cancers, but even more importantly, the biology of changes to the disease and the microenvironment created by surgical interventions. Animal models additionally allow for the development of image-guided surgery systems, novel strategies of intraoperative adjuvant treatment, and patient "avatars" to test innovative anticancer drug combinations. In clinical surgical research, surgical techniques are validated in clinical trials for effectiveness of tumor control and improvement of functional recovery of the patient. In conclusion, surgical research for head and neck cancer is an active field spanning across the entire breadth of basic and clinical science devoted to a better understanding of what surgery does to the disease and to the patient.