R011: Donor Site Morbidity with Radial Forearm Free Flap

R011: Donor Site Morbidity with Radial Forearm Free Flap

Research Posters—Thursday R009 Rhinoplasty: Improvement of the Internal Nasal Valve Cynthia Nicolau, MD (presenter); Mirian Grupenmarcher, MD PROBLEM...

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Research Posters—Thursday

R009 Rhinoplasty: Improvement of the Internal Nasal Valve Cynthia Nicolau, MD (presenter); Mirian Grupenmarcher, MD PROBLEM: Preservation of internal nasal valve function in primary and secondary rhinoplasty. METHODS: Twenty-nine patients: First group-19 patients with potential obstructive nasal problems after rhinoplasty (narrow nose, short nasal bones), and the second group-10 patients with secondary rhinoplasty who underwent surgical correction by open and closed rhinoplasty, using flaring sutures of upper cartilages associated or not to spreader graft, between Dec. 1, 2005 and July 1, 2006. RESULTS: Flaring sutures improved the cross-sectional areas in rhinometry by 10% in patients with primary rhinoplasty and by 12% in the second group. Spreader grafts combined with flaring sutures by 18%. Mean nasal patency scores improved. CONCLUSION: The simplicity of the flaring suture of upper lateral cartilages along with its potential to minimize the risk of internal valve disturbance (for the noses with a high and narrow roof) justifies, in the experience of the presenters, its use. SIGNIFICANCE: This is a valuable addition to the armamentarium of the closed or open rhinoplasty surgeon: better aesthetic results can be achieved, besides the great functional outcome.

R010 Fibrin Glue Modulates Fat Graft Resorption in Nu/ Nu Mice Michael J Reilly, MD (presenter); Stephen Bradley Baker, MD, DDS; Ali Al-Attar, MD; Michael D Johnson, PhD PROBLEM: Autologous fat grafting is associated with high and unpredictable resorption rates in clinical applications. Fi-

brin Glue (FG) is a surgical tissue adhesive derived from human blood products. It has been shown to be effective as a biologic adjunct in multiple surgical procedures, including skin grafts, local tissue flaps, microvascular anastamoses, dural closures, and nerve repair. The team hypothesized that FG could inhibit resorption of fat grafts in an animal model. METHODS: Human fat from abdominoplasty specimens was implanted into athymic nude mice (nu/nu) with 5 percent fibrin glue. Fat graft resorption was serially evaluated for 16 weeks using three-dimensional ultrasound. Mice were sacrificed, and fat grafts were harvested and stained for histologic analysis. RESULTS: FG affected fat graft resorption rates in athymic nude mice as compared to control subjects. Implanted fat grafts resorbed approximately 87 percent over 16 weeks in the control group and 75 percent in the FG treatment group. Histologic analysis demonstrated a significant difference in graft morphology and cyst formation. CONCLUSION: FG affects resorption rates in this animal model of autologous fat grafting. FG may provide a temporary scaffold in the implanted fat necessary for neoangiogenesis and improved graft survival. Further research is required at the cellular level in order to investigate this possibility. SIGNIFICANCE: Predictable modulation of fat graft resorption may make this the ideal technique for soft tissue volume restoration in the head and neck. SUPPORT: NIH RO3 grant in the name of Dr. Stephen B. Baker, MD, D.D.S.

R011 Donor Site Morbidity with Radial Forearm Free Flap Maya Sardesai, MD (presenter); John H-J Yoo, MD; Jason H Franklin, MD, FRCSC; Connie Wyllie Naftel, MD; Linda Denning; Kevin Fung, MD, FRCS(C) PROBLEM: To comprehensively evaluate long-term quantitative and qualitative donor site morbidity following radial forearm free tissue harvest. METHODS: A single-center prospective cohort study with internal controls was undertaken. Experienced occupational therapists measured active range of motion (ROM) of the elbow, forearm, wrist, and digits preoperatively and at least six months postoperatively. Static grip and pinch strength, hand dexterity, and skin sensation were also evaluated. Qualitative assessment of patient perception was determined using the Michigan Hand Outcomes Questionnaire (MHQ), a validated quality-of-life instrument. Quantitative primary outcome measures were (1) wrist flexion and extension, (2) forearm pronation and supination, and (3) hand dexterity. The qualitative primary outcome measure was overall MHQ score. RESULTS: With respect to quantitative primary outcome measures, a statistically significant reduction in wrist extension


RESULTS: All animals demonstrated mucocele formation on gross examination and histologic sectioning. There was no gross or histological evidence of bony erosion. The nasofrontal outflow tracts remained occluded. CONCLUSION: The study provides a suitable animal model for the investigation of mucocele formation in the frontal sinus. The goat frontal sinus and nasofrontal outflow tracts provides an excellent model for frontal sinus studies as they are comparable in size to humans. The results provide further evidence of mucocele formation with occluded nasofrontal outflow tracts. SIGNIFICANCE: This study provides a suitable animal model for the study of the frontal sinus when there is alteration to the naso-frontal outflow tracts. It is the first designed study in the english literature which demonstrates mucocele formation in the adult goat, an animal with frontal sinuses similar in size and function to that of humans.



Otolaryngology-Head and Neck Surgery, Vol 137, No 2S, August 2007

was found (p ⫽ 0.012). The remaining quantitative primary outcome measurements demonstrated no significant differences. In addition, a statistically significant reduction in index distal interphalangeal joint range of motion in the operated hand was seen (p ⫽ 0.047). On the control (unoperated) side, a statistically significant improvement in thumb interphalangeal range of motion (p ⫽ 0.016) and decrease in lateral pinch strength (p ⫽ 0.029) was found. With respect to the qualitative primary outcome measure, no statistical difference in overall MHQ score was found (p ⬎ 0.05). CONCLUSION: The radial forearm free flap results in slight but measurable quantitative changes in hand function on the operated side, and measurable compensatory changes on the unoperated side. There are limited changes in patient perception when measured prospectively with validated quality-oflife measures. SIGNIFICANCE: This long-term, prospective, internally controlled study uses both comprehensive validated quantitative measures, as well as a validated quality-of-life instrument. The results objectively confirm that the radial forearm free flap carries limited donor-site morbidity.

R012 Human Skeletal Muscle Cell Culture for Tissue Engineering Jens Stern-Straeter, MD (presenter); Frank Riedel, MD; Gregor Bran, MD; Karl Hoermann, MD; Ulrich R Goessler, MD PROBLEM: Skeletal muscle tissue engineering is a promising specialty that aims at the reconstruction of skeletal muscle loss. The concept of in vitro tissue engineering tries to achieve this goal by creating differentiated, functional muscle tissue by extracting stem cells followed by their expansion and differentiation in a controlled environment with subsequent re-implantation. Nevertheless a prerequisite is the ability to cultivate and differentiate human skeletal muscle cell cultures. Optimal culture conditions have to be investigated for a later clinical utilization. Therefore, the proliferation of human cells in different environments (e.g. coated culture flasks) was investigated and the differentiation potential in different culture media evaluated. METHODS: Primary human myoblasts were extracted from muscle biopsies. Myoblast purity was verified by immunostainings against the skeletal muscle specific protein desmin. Proliferation was analyzed by the AlamarBlue® assay. Gene expression of marker genes like Myogenin, Myo D, Myf 5 and MHC were analyzed by RT-PCR. Immunostainings against sarcomeric-actin as differentiation marker were performed. RESULTS: Myoblast cell cultures showed a greater proliferation rate in growth medium compared to the differentiation medium. In both media marker gene expression could be detected verifying the occurring maturation of mononucleated myoblasts to multinucleated myofibers. The differentiation

could also be detected on protein level by immunostainings against sacromeric-actin. CONCLUSION: In order to gain more insight in the differentiation process, the behavior of human myoblasts in different environments was analyzed and shown that cells proliferate and differentiate under different culture conditions. In future studies one should analyze the behavior of myoblasts in three-dimensional environments and compare them to the obtained results. SIGNIFICANCE: Development and characterization of human myoblast cell cultures is a prerequisite for the tissue engineering of skeletal muscle. This study contributes to the understanding of myoblast differentiation and helps to improve culture systems for a later clinical utilization.

R013 Disruption of DNA Damage Signaling: A Novel Therapy for HNSCC Waleed M Abuzeid, MD (presenter); Khurram Khan, MD; Xiaoling Jiang, PhD; Xin Cao; Bert W O’Malley, Jr, MD; Daqing Li, MD PROBLEM: Chemoradiation for head and neck squamous cell carcinoma (HNSCC) has limited efficacy due to treatment resistance resulting from enhanced DNA repair. This leads to dose escalations and severe toxicity. The authors have developed a system that exploits the uncontrolled proliferation of cancer cells to induce cell death. Poly(ADP)-ribose polymerase (PARP)-1 mediates single-strand break (SSB) repair. PARP-1 inhibition causes persistent SSBs, which are converted to double-strand breaks (DSBs) during cell division. The Mre11/Rad50/Nbs1 (MRN) complex repairs these DSBs. Nbs1 is a key upstream DNA damage sensor that regulates downstream DSB repair. Disruption of the DSB pathway results in compensatory up-regulation of SSB repair and vice versa. However, PARP-1 inhibition, on a background of impaired DSB repair, is profoundly cytotoxic. It is hypothesized that disruption of Nbs1 function, combined with PARP-1 inhibition, will produce marked cytotoxicity in HNSCC without requiring chemotherapy or radiation. METHODS: Cells from FaDu and chemoresistant JHU006 HNSCC cell lines were divided into 4 groups: no treatment, PARP-1 inhibitor GPI-15427 (MGI-Pharma) monotherapy, adenovirus expressing mutant Nbs1(Ad-Nbs1) alone, and combined GPI-15427 and Ad-Nbs1 therapy. Cell proliferation was assessed by MTT assay. RESULTS: PARP-1 inhibition, combined with Ad-Nbs1, depressed cell growth within 48 hours in both cell lines. In JHU006, sustained cell death occurred from day 3 in the combined therapy group and, by day 6, cell number was reduced by 43% versus controls, 27% versus Ad-Nbs1 alone, and 42% versus GPI-15427 alone (p⬍0.001 all groups). In FaDu, combined treatment produced cell regression from day 5 and reduction in cell number of 38% versus controls, 24% versus Ad-Nbs1, and 30% versus GPI-15427 (p⬍0.001 all groups).