PLASTIC SURGERY I

Abnormal primary tissue collagen composition inrecurrent incisional hernia patientsBrent C White, MD, Charles Osier, BS, Nana Gletsu, PhD,Mercedeh Baghai, MD, Melanie Sherman, PhD,C Daniel Smith, MD, FACS, Bruce Ramshaw, MD, FACS,Edward Lin, DOEmory University School of Medicine, Atlanta, GA

INTRODUCTION: Recurrence of incisional hernia may be as high as50%. Abnormal collagen I/III ratios have been observed within scartissue of patients with recurrent incisional hernias. We sought todetermine whether collagen composition in primary, non-scarredconnective tissue was similarly affected in these patients.

METHODS: In this prospective, case-control study, non-scarred pri-mary abdominal wall skin and fascia biopsies were obtained in twelvepatients with a history of recurrent incisional hernias and elevenpatients without history of hernia, while undergoing abdominallaparoscopic surgery. Tissue protein expression of collagen I and IIIwas assessed by immunohistochemistry followed by densitometryanalysis.

RESULTS: The collagen I/III ratio in skin biopsies from the recur-rent hernia group was significantly less compared to controls(0.88�0.01 vs. 0.98�0.04 respectively, p�0.05). Fascia biopsiesfrom patients with recurrent hernias was not significantly decreasedin collagen I/III ratio compared to controls (0.90�0.04 vs.0.94�0.03 respectively, p�0.17).

CONCLUSIONS: Decreased collagen I/III ratios within the skin ofrecurrent hernia patients not involved with scar or healing tissuesuggest an underlying collagen composition defect. Such a primarycollagen defect, in addition to abnormal scar formation, likely playsa significant role in the pathogenesis of recurrent incisional hernias.With further characterization, these differences in primary tissuescould provide a preoperative prediction of hernia formation risk.

bFGF gene transfer by adeno-associated viral 2vectors decreases work of active digital flexion andadhesion formation: An in vivo study up to endtendon healing stageJin Bo Tang, MD, Yi Cao, MD, Bei Zhu, MD, Ke-Qin Xin, PhD,Xiao Tian Wang, MD, Paul Y Liu, MDNantong University, China; and Roger Williams Hospital,Providence, RI

INTRODUCTION: We investigated effects of delivery of AAV2-bFGF to injured flexor tendon in a clinically relevant injury modelon several ultimate outcome measures at end tendon healing stage --ultimate gliding function, work of active digital flexion and extent ofmatured adhesions.

METHODS: 40 long toes from 20 chickens were divided into 2groups of 20. The flexor digitorum profundus (FDP) tendons werecut and were repaired surgically. In AAV2-bFGF group, a total of 2 X109 particles of AAV2-bFGF gene were injected to tendon stumps.In non-treatment group, the tendons received no injection. At the

end of 8 and 12 weeks, work of digital flexion and FDP tendonexcursions were tested and peritendinous adhesions were scored.

RESULTS: At 12 weeks, work of digital flexion in the AAV2-bFGFtreatment group (0.021 �/� 0.006 J) was significantly less than thatof non-treatment controls (0.033 �/� 0.015 J)(p � 0.05). Excur-sions of the AAV2-bFGF treated tendons were not significantlychanged compared with non-treated tendons. Adhesion scores oftreated tendons (2.8 �/� 0.7 points) were less than the controltendons (3.8 �/� 0.9 points)(p � 0.05). Work of flexion at 12weeks was significantly less than that at 8 weeks (p � 0.01).

CONCLUSIONS: bFGF gene transfer via AAV2 vectors to digitalflexor tendon significantly decreases energy required to flex the digitsand adhesion formations. We evaluated the outcomes at the end stagewhen healing had matured and function was steady. These findingssuggest that AAV2-bFGF gene therapy benefits ultimate digital mo-tion.

Biological and biomechanical assessment of a long-term bioresorbable silk-derived surgical mesh in anabdominal body wall defect modelGregory H Altman, PhD, Rebecca L Horan, PhD,Diah S Bramono, PhD, Quincey Simmons, DVM,Jingsong Chen, MD, Enrico Mortarino, BS, Heather E Boepple, BS,Ivan Toponarski, MS, Adam L Collette, BS, Jason S Prudom, BSSerica Technologies, Inc, NIST Advance Technology Program,Charles River, Medford, MA

INTRODUCTION: Body wall defect repair would be enhanced by amechanically robust, physically tailorable, completely bioresorbablemesh scaffold that (i) supports rapid tissue ingrowth and develop-ment, while (ii) reducing complications associated with permanentsynthetic, allogenic and xenogenic implants. We hypothesized a bio-engineered silkworm silk mesh bioresorbs at a rate sufficient to sup-port ingrowth and transfer of load bearing responsibility to hosttissue, thereby facilitating favorable autogenic tissue repair.

METHODS: Thirty-six rats were divided into two groups: bioengi-neered silk mesh (test) and polyester mesh (control). A ’U’ incisionwas made, the skin bluntly dissected, and a 1-cm diameter full-thickness abdominal defect punched. A 4x4cm implant was centeredover the defect and anchored circumferentially with six interruptedpolypropylene stitches. Histopathology, histomorphometry and bio-mechanical analyses were performed 30 and 94-days post-implantation.

RESULTS: There was no gross mesh damage, shrinking or stretch-ing observed. There were no organ herniations beyond suture lines.Equivalent histological responses were observed with significantlygreater tissue ingrowth in the test group. A significant 33% and 57%test device mass reduction was observed at 30 and 94-days; despitecontinued bioresorption, the test device reinforced defect strength at30 and 94-days did not differ significantly, nor did they differ fromtime�0 control mesh or native musculofascia strength. No particu-late debris was observed within the lymph nodes.

S53© 2007 by the American College of Surgeons ISSN 1072-7515/07/$32.00Published by Elsevier Inc.