Julio A. Clavijo-Alvarez

Delivery of Adipose-Derived Precursor Cells for Peripheral Nerve Repair

To test the hypothesis that the transplantation of adipose precursor cells (APCs) improves nerve regeneration and functional recovery, human APCs were transplanted into the lumen of a nerve guide in a 6-mm unilateral sciatic nerve defect in athymic rats. The three control groups for the study were biodegradable, polycaprolactone-based nerve conduit without APCs, autograft, and empty defect. Behavioral tests were performed every 3 weeks, and the sciatic functional index (SFI) was calculated based on measurements from the hindlimb prints. After 12 weeks, the nerve as well as right and left gastrocnemius muscles were removed and preserved for histological evaluation. Full regeneration of the sciatic nerve occurred on the rats that received the autograft, the guide, and the guide with APCs; no regeneration was observed on any of the rats in which the defect was left untreated (empty defect). APCs survived transplantation for up to 12 weeks in the injured peripheral nerve. No significant colocalization was observed between the immunostaining for glial fibrillary protein and anti-human lamin A/C, implying that the APCs did not differentiate into Schwann cells at the site of injury. In comparison with the rats with untreated defects, a decrease in muscle atrophy was observed on those rats that received the autograft and the guide with cells as indicated by the gastrocnemius muscle weight ratio and the muscle fiber ratio. Significant differences in SFI were observed 3 weeks postinjury between the rats in which the guide was left empty and those that received the guide with APCs; however, these differences were not observed at 12 weeks. The transplantation of APCs promoted the formation of a more robust nerve as evidenced by the results from the cross-sectional area of regenerated nerve, and the transplantation of APCs produced a decrease in muscle atrophy.

Comparison of biodegradable conduits within aged rat sciatic nerve defects.

Background: Considering that little is known about the peripheral nerve regenerative capacity of elderly patients, the authors studied nerve regenerative capacity in aged rats and compared the effect of three synthetic nerve guides with different material characteristics and porosity. The authors hypothesized that the use of a biodegradable composite nerve guide (CultiGuides) would promote nerve regeneration and functional recovery in a manner similar to treatment with autografts or U.S. Food and Drug Administration–approved polyglycolic acid Neurotubes in an aged rat sciatic nerve defect model. Methods: Aged Sprague-Dawley rats (11 months old) underwent a 1-cm sciatic nerve resection in the right leg [group 1, control (contralateral leg samples), n = 10; group 2, negative (nerve gap defect), n = 6; group 3, autograft, n = 10; group 4, polycaprolactone, n = 10; group 5, CultiGuides, n = 10; and group 6, Neurotube, n = 10]. Results: After 12 weeks, the negative group did not demonstrate any nerve regeneration. In the regenerated and distal nerve, all treated groups had increased myelinated areas compared with the negative control. In the regenerated nerve, there was a significant increase in myelination in the Neurotube group compared with the polycaprolactone group (p < 0.001). However, in the distal nerve, there were no differences among the treatment groups. Walking track analyses and gastrocnemius muscle weight ratios were not different among treatment groups 3 through 6. Conclusions: The results showed differences in myelination; Neurotubes promoted the highest degree of myelination (p < 0.001) as compared with all groups. The authors found no improvement in function of the repaired nerve as measured by percentage of autotomy, the sciatic function index, and gastrocnemius muscle weight. No group was able to recover function in this aged model.

A novel perfluoroelastomer seeded with adipose-derived stem cells for soft-tissue repair.

Background: There is a need for engineered soft tissue in reconstructive surgery, particularly after tumor removal. An ideal implant that will provide structural support and a favorable environment for growing cells is a key element in the process of tissue engineering. Nonbiodegradable materials that become well incorporated within the new tissue are a good solution, but many such materials do not have a surface favorable for cell adherence and proliferation. The authors hypothesized that the modification of the pore size in a novel fluoropolymer would improve the adherence and enhance the proliferation of adipose-derived stem cells. Methods: Fluoropolymers with two varying pore size ranges were examined. Fluoropolymer compound U48 (pore size, 100 to 180 &mgr;m) and fluoropolymer compound P54 (pore size, 10 to 55 &mgr;m) were seeded with human adipose-derived stem cells, and cell adherence to the material was measured after 4 hours and cell proliferation was measured after 72 hours. Cell-seeded constructs were implanted subcutaneously in a nude mouse model for 30 days. Results: Fluoropolymer surface treatment with fibronectin improved the attachment of adipose-derived stem cells to the well plates but did not improve attachment to the fluoropolymer, regardless of pore size. Fluoropolymer U48 increases the adherence and provides a favorable surface for proliferation of adipose-derived stem cells. Conclusions: After subcutaneous implantation into nude mice, tissue growth was observed in the fluoropolymer samples with the larger pore size. The characteristics of this new material will allow for future clinical applications in plastic and reconstructive surgery.

Liposuction of the arm concurrent with brachioplasty in the massive weight loss patient: is it safe?

Background: Brachioplasty continues to be a sought-after procedure among the massive weight loss population. Residual adiposity of the upper arm can make this procedure more difficult. The authors sought to determine the safety of arm liposuction outside the region of excision with concomitant excisional brachioplasty. Methods: Data were analyzed from a prospective registry of massive weight loss patients who underwent brachioplasty alone or with concurrent arm liposuction. Variables examined included age, sex, body mass index, method of weight loss, medical comorbidities, and smoking status. Outcomes included complications such as seroma, wound dehiscence, infection, hematoma, lymphedema, and need for revision. Multivariate analyses were performed to assess outcome measures. Results: One hundred forty-four patients (139 women and five men; mean body mass index, 29.6 ± 4.1 kg/m2; mean age, 46 ± 10.7 years) underwent brachioplasty. Sixty-four patients had concomitant arm liposuction at the time of brachioplasty. The remaining 80 patients underwent excisional brachioplasty alone. Despite significantly higher operative body mass indices among those undergoing concurrent liposuction, no significant differences in complication rates were seen between the liposuction and excision-alone cohorts for seroma (19.1 percent versus 23.1 percent), wound dehiscence (7.9 percent versus 2.6 percent), infection (4.8 percent versus 6.4 percent), hematoma (3.2 percent versus 0 percent), or lymphedema (3.2 percent versus 1.3 percent). Revision rates were similar between the two groups (9.5 percent with liposuction and 8.9 percent without liposuction). Conclusion: Liposuction can be performed safely and effectively outside the region of excision at the time of brachioplasty without the need for prior debulking or staged arm-contouring procedures. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Development of consensus guidelines for venous thromboembolism prophylaxis in patients undergoing microvascular reconstruction of the mandible

The purpose of this study was to determine how guidelines for venous thromboembolism prophylaxis can be applied to patients undergoing microsurgical reconstruction of the mandible.

Risk factors for death in elderly patients with facial fractures secondary to falls.

BackgroundCraniomaxillofacial trauma is associated with severe injuries and disability. There are no recent reports analyzing the demographics of facial trauma in elderly patients. Our objective was to review the demographics, outcomes, and risk factors associated with death in elderly patients with facial fractures in a single-institution level I trauma center. MethodsWe performed a retrospective review of the University of Pittsburgh Medical Center Trauma Registry from January 1999 to December 2008 in an institutional review board–approved protocol. The search query included all types of craniofacial trauma using International Classification of Diseases, Ninth Revision coding. A &khgr;2 test was used for analyzing categorical data. Continuous data were analyzed using unpaired t-test or analysis of variance. Logistic regressions were done to determine odds ratio (OR) for death. P = 0.05 was deemed significant. ResultsA total of 16,528 patients with facial trauma were identified. Of these, 4536 patients had falls. Among the falls, 1020 patients had facial fractures. Finally, 460 patients were younger than 65 years, and 560 were older than 65 years. The variable with the highest odds for mortality in patients with facial fractures was intensive care unit admission (OR, 13.1), followed by acute renal failure (OR, 10.3), medical history of myocardial infarction (OR, 5.1), coagulopathy (OR, 4.78), age older than 65 years (OR, 4.13), acute respiratory failure (OR, 3.55), Abbreviated Injury Scale score greater than 3 at the head (OR, 3.5), congestive heart failure (OR, 2.64), history of cardiac surgery (OR, 2.4), and vault skull fracture (OR, 2.35). ConclusionsCraniofacial trauma is a serious condition in the elderly. Associated injuries are demonstrated to have a deleterious effect on survival. Recognition of these risk factors is likely to promote the development of preventive measurements to decrease fatal outcomes.

Approach to Venous Thromboembolism Prophylaxis: Are We Evolving Fast Enough in Plastic Surgery?

Venous thromboembolism has become a target for research by the American Society of Plastic Surgery. The current article reviews the steps that plastic surgeons and the American Society of Plastic Surgery have taken for creating guidelines in our field. We summarized the current reported incidences of venous thromboembolism in various plastic surgical procedures, and reviewed the current efforts that the society is taking to address the burden of this deadly preventable disease.

158C: RISK FACTORS FOR DEATH IN ELDERLY PATIENTS WITH FACIAL FRACTURES SECONDARY TO FALLS: A. A REVIEW OF 1020 CASES OVER 10 YEARS

Background: Bottoming out (BO) is a well observed phenomenon occurring after all types of breast reduction (BR) surgery. Our team used 3-dimensional (3D) imaging to objectively demonstrate that significant BO occurs in short, scar medial pedicle (MP) BR during the first postoperative year (POY), with no further changes occurring in the second POY. The following study uses 3D imaging to objectively evaluate how the breast changes during the third POY after short-scar, MP BR.