Faculty Bibliography

Repair of large complex abdominal hernias with significant loss of domain requires component separation in combination with either a synthetic or biologic interpositional material. We previously described an algorithm for complex abdominal hernia repair, which incorporates Alloderm as an interpositional material and selective use of prolene mesh as an overlay. We now report recurrent laxity in a series of patients who were repaired with interpositional Alloderm alone without prolene mesh overlay. We reviewed all patients who underwent repair of massive ventral hernias and identified 7 patients who presented with abdominal wall laxity following component separation with interpositional Alloderm alone. All patients developed laxity within 12 months and required a secondary procedure. At the time of re-exploration, severe attenuation in the Alloderm was noted. The segment was excised, the edges closed primarily, and prolene mesh was placed as an onlay. Although Alloderm has been reported to be an effective biologic material for abdominal hernia reconstruction, we have noted significant laxity requiring secondary intervention.

The purpose of this study was to develop a nonhuman primate model for heterotopic composite tissue facial transplantation in which to study the natural history of facial transplantation and evaluate immunosuppressive regimens.A composite oromandibular facial segment transplant based on the common carotid artery was evaluated. Flaps from 7 cynomolgus monkeys were transplanted to the groins of 7 recipients at the superficial femoral artery and vein. The immunosuppressive regimen consisted of thymoglobulin, rapamycin, and tacrolimus. Allograft survival ranged from 6 to 129 days. Histology performed in the long-term survivor at the time of necropsy revealed extensive inflammation and necrosis of the allograft skin; however, muscle and bone elements were viable, with minimal inflammation. This heterotopic facial transplantation model avoids the potential morbidity of mandibular resection and orthotopic facial transplantation. Our work also concurs with the work of other groups who found that the skin component is the most antigenic.

BACKGROUND: The lower abdomen is the most popular donor site for autologous tissue breast reconstruction. Several studies have reported abdominal morbidity following pedicled and free flap reconstructions using this donor site, yet few studies have compared the various types of free flaps and investigated specific operative and patient-related factors that are associated with higher rates of abdominal complications. METHODS: The authors conducted a retrospective review of all free flap breast reconstructions performed at University of California Los Angeles Medical Center between July of 2002 and July of 2005. RESULTS: A total of 279 patients underwent 211 unilateral and 68 bilateral reconstructions, totaling 347 flaps. Eleven percent were free transverse rectus abdominis myocutaneous (TRAM) flaps, 52 percent were muscle-sparing free TRAM flaps, and 37 percent were deep inferior epigastric perforator (DIEP) flaps. Mean follow-up was 29.9 months. There were 30 total abdominal complications (10.9 percent of patients), including 17 rectus bulges and five hernias. Free TRAM reconstructions had a significantly higher rate of donor-site complications than did DIEP reconstructions. Bilateral flap harvests and obesity (body mass index >30) were significant risk factors for (1) any donor-site complication and (2) rectus bulge/hernia formation. There was no significant increase in donor-site complications associated with various prior abdominal operations. CONCLUSIONS: Donor-site complications are not uncommon, but paying careful attention to patient comorbidities when selecting an operative approach (bilateral versus unilateral, free TRAM versus DIEP, and so on) can minimize postoperative abdominal complications. Furthermore, the results corroborate the recent literature suggesting there is little functional difference in patients receiving muscle-sparing free TRAM versus DIEP reconstructions.

To date, reports on the incidence and distribution of pediatric facial fractures have been inconsistent and have originated only from institutional studies. The need for current national data exists. We examined the Kids' Inpatient Database and the Nationwide Inpatient Sample to obtain national information on facial fracture discharges from 1997 to 2003. Data showed that pediatric patients (age, 0-17 years) make up 14.7% of all facial fractures, with children aged 1 to 4 years comprising only 5.6% of the total and children 15 to 17 years old making up more than half the group. The male-to-female ratio was 2.5. Significantly lengthier hospitalizations were observed with female patients, Medicaid insurance, teaching hospitals, government hospitals, and metropolitan hospitals. Significantly higher charges were associated with patients aged 1 to 4 years, Medicaid insurance, Western US geography, teaching hospitals, metropolitan hospitals, and children's hospitals. During the 6-year period of this study, there was a trend toward (1) increased hospital charges (with stable costs), (2) more patients treated at teaching hospitals, and (3) a convergence in length of stay between hospitals with differing ownerships (with government hospitals having progressively shorter hospitalizations, whereas private for-profit hospitals have progressively lengthier hospitalizations). The incidence of facial fractures in children is small yet significant and has remained stable during the past few decades. Certain patient populations are prone to facial fractures, and various patient and hospital factors are associated with lengthier and more expensive hospitalizations. An understanding of disparities in resource use among various patient, hospital, and geographic settings is critical for physicians and policy makers.

Dermal lymphatic malformations are rare congenital hamartomas of superficial lymphatics characterized by high recurrence rates after excision. The standard therapy for a single lesion is surgical excision with wide margins, which reduces recurrence but can have a potentially unacceptable aesthetic outcome. A case of a 24-year-old woman with a 6 cm x 5 cm dermal lymphatic malformation on her right thigh, diagnosed by clinical history, physical examination, magnetic resonance imaging and pathological findings, is reported. The patient underwent wide local excision with split-thickness skin grafting. After pathological examination revealed negative margins, the patient underwent tissue expander placement and excision of the skin graft with primary closure. The lesion did not recur, and the patient achieved a satisfactory aesthetic result. The present case represents the first report of the use of tissue expanders to treat dermal lymphatic malformations in the lower extremity and demonstrates a safe, staged approach to successful treatment.

The incidence and prevalence of chronic and diabetic wounds are increasing and clinical treatments to tackle these epidemics are still insufficient. In this study, we tested the ability of freeze-dried platelet-rich plasma (PRP) and an allogenic micronized acellular dermal matrix alone and in combination to modulate diabetic wound healing. Therapeutic materials were applied to 1.0 cm(2) excisional wounds on genetically diabetic (db/db) mice. Wound-healing kinetics and new tissue formation were studied at 9 and 21 days posttreatment. Quantitative immunohistochemistry was used to study vascularity and cellular proliferation (days 9 and 21), and collagen deposition was evaluated 21 days postwounding. In vitro, micronized allogenic dermis, when combined with PRP, absorbed nearly 50% of original platelet-derived growth factor, transforming growth factor-beta, vascular endothelial growth factor, and epidermal growth factor from platelets and stimulated fibroblast proliferation. In vivo, micronized dermis increased the formation of vascularized wound tissue by day 9. Freeze-dried PRP alone or in combination with micronized dermis increased wound tissue revascularization and proliferation compared with spontaneous healing. The increase in cell proliferation persisted until day 21 only when freeze-dried PRP was used in combination with micronized dermis. These results indicate that micronized allogenic dermis may be used to provide a dermal matrix to stimulate tissue formation and the combination with PRP may confer additional beneficial growth factors to chronic or diabetic wounds.

BACKGROUND: Poly-N-acetyl glucosamine (pGlcNAc) nanofiber-based materials, produced by a marine microalga, have been characterized as effective hemostatic agents. In this study, we hypothesized that a pGlcNAc fiber patch may enhance wound healing in the db/db mouse. METHODS: pGlcNAc patches were applied on 1-cm, full-thickness, skin wounds in the db/db mouse model. Wounds (n = 15 per group) were dressed with a pGlcNAc nanofiber patch for 1 hour, 24 hours, or left untreated. After the application time, patches were removed and wounds were allowed to heal spontaneously. The rate of wound closure was evaluated by digital analysis of unclosed wound area as a function of time. At day 10, wounds (n = 7 per group) were harvested and quantified with immunohistochemical markers of proliferation (Ki-67) and vascularization (platelet endothelial cell adhesion molecule). RESULTS: Wounds dressed with pGlcNAc patches for 1 hour closed faster than control wounds, reaching 90% closure in 16.6 days, 9 days faster than untreated wounds. Granulation tissue showed higher levels of proliferation and vascularization after 1-hour treatment than the 24-hour and left-untreated groups. Foreign body reaction to the material was not noted in applications up to 24 hours. DISCUSSION: In addition to its hemostatic properties, the pGlcNAc material also appears to accelerate wound closure in healing-impaired genetically diabetic mice. This material, with its combination of hemostatic and wound healing properties, has the potential to be effective agent for the treatment of complicated wounds.

Surgical ablation for oncologic disease requiring skull base resection can result in both facial disfigurement and a complex wound defect with exposed orbital content, oral cavity, bone, and dural lining. Inadequate reconstruction can result in brain abscesses, meningitis, osteomyelitis, visual disturbances, speech impairment, and altered oral intake. This study assesses the functional outcomes of patients who undergo anterior and middle cranial fossa skull base reconstruction using microsurgical free tissue transfer techniques. Using a prospectively maintained database, a 10-year, single institution retrospective chart review was performed on patients who had surgery for anterior and middle cranial base tumor resections. The type of resection, reconstruction method, complication rate, and functional outcomes were reviewed. From 1992 to 2003, 70 patients (49 men, 21 women) with a mean age of 54 (age 6-78) underwent anterior and middle cranial skull base tumor resection and reconstruction. The patients were divided into the following groups: maxillectomy with orbital content preservation (n = 21), orbitomaxillectomy with palatal preservation (n = 26), and orbitomaxillectomy with palatal resection (n = 23). The average length of hospital stay was 12.6 days. The vertical rectus abdominis myocutaneous flap was used in the majority of cases to correct midface defects. Two flaps required emergent re-exploration; however, there were no flap failures. Early and late postoperative complications were investigated. Cerebrospinal fluid was observed infrequently (7%) and did not require additional surgical intervention. Intracranial abscesses were encountered rarely (1.4%). Patients who had maxillectomy with orbital preservation and reconstruction had minor ophthalmologic eyelid changes that occurred frequently. Patients who required palatal reconstruction had a normal or intelligible speech (93%) and unrestricted or soft diet (88%). Using a multidisciplinary surgical team approach, there is an increasing role for reconstruction of complex oncologic midface resection defects using microvascular surgical techniques. Early/late complications and functional problems after anterior cranial base resections are uncommon when free tissue transfer is used concomitantly.