Faculty Bibliography

Soft-tissue reconstruction of traumatic patella and proximal tibial defects is challenging. Pedicled perforator-based adipocutaneous rotation flaps are a versatile local option as they have axial perfusion and greater freedom of transposition compared with random-pattern flaps, and replace the ideal tissue properties of this anatomic region.Experimental: Anatomic dissections were performed on 15 fresh cadaver legs and location of the dominant perforator measured. Clinical: A retrospective review was conducted at the University of Maryland/R Adams Cowley Shock Trauma Center evaluating patients over a 3-year period.Experimental: Cadaver dissections confirmed a principal perforator at 11.4 +/- 1.6 cm inferior to the patella. This vessel is consistently suitable in length and caliber for large rotation flap design. Clinical: Anterior tibial artery perforator flaps were performed on 4 patients following Gustilo IIIB wounds to the patella and tibial plateau. Two patients had rotation flap reconstructions to salvage failed gastrocnemius muscle flaps. All flaps were successful, however, one patient had overwhelming hardware infection several months later despite successfully healed flap.Local anterior tibial artery perforator flaps based on predictable perforators provide reliable coverage of patella and knee defects, bestowing versatility and flexibility to the reconstructive surgeon's armamentarium.

High velocity injuries have traditionally been covered with free muscle flaps. We sought to evaluate the utility of the anterolateral thigh flap (ALT) flap as a primary choice in reconstructing traumatic injuries in Western patients.A retrospective chart review was conducted of 122 patients treated at the R Adams Cowley Shock Trauma Center and at the Louisiana State University Trauma Center. Data collected included defect size, donor site location, flap composition and size, number of anastamoses, number of perforators, donor site closure, and complications.A total of 127 ALT flap reconstructions were performed. About 74% involved the lower extremity, 12% head and neck, 11% upper extremity, 2% abdomen, <1% chest, and <1% pelvis. The success rate was 96% with 3 total flap failures and 2 partial flap failures. Average follow-up was 9.3 months.The results of this review confirm that the ALT flap is a reliable, versatile tool for managing composite traumatic injuries.

BACKGROUND: Composite tissue allotransplantation may have different immunosuppressive requirements and manifest different complications compared with solid organ transplantation. We developed a non-human primate facial composite tissue allotransplantation model to investigate strategies to achieve prolonged graft survival and immunologic responses unique to these allografts. METHODS: Composite facial subunits consisting of skin, muscle, and bone were heterotopically transplanted to mixed lymphocyte reaction-mismatched Cynomolgus macaques. Tacrolimus monotherapy was administered via continuous intravenous infusion for 28 days then tapered to daily intramuscular doses. RESULTS: Five of the six animals treated with tacrolimus monotherapy demonstrated rejection-free graft survival up to 177 days (mean, 113 days). All animals with prolonged graft survival developed posttransplant lymphoproliferative disorders (PTLD). Three animals converted to rapamycin after 28 days of rejection of their allografts, but did not develop PTLD. Genotypic analysis of PTLD tumors demonstrated donor origin in three of the five analyzed by short-tandem repeats. Sustained alloantibodies were detected in rejecting grafts and absent in nonrejecting grafts. CONCLUSIONS: Tacrolimus monotherapy provided prolonged rejection-free survival of composite facial allografts in a non-human primate model but was associated with the development of a high frequency of donor-derived PTLD tumors. The transplantation of a large volume of vascularized bone marrow in composite tissue allografts may be a risk factor for PTLD development.

In the last two decades, the anterolateral thigh flap has emerged as one of the most popular reconstructive options for multiple body sites. Based on a perforator flap harvest concept, the flap encompasses the advantages of versatility, pliability, and potential for composite tissue replacement. Although numerous anatomical variations exist, these are well-described, and flap safety remains uncompromised if certain anatomical boundaries are respected. Careful preoperative planning and identification of perforators remain the cornerstone of successful flap harvest. Once perforators are identified, variations in skin paddle design allow for multiple skin paddle configurations, central or eccentric orientations, and custom-made flaps tailored to fit almost any defect. A suprafascial dissection allows for "ultra-thin" flaps ideal for folding, tubing, or packing purposes. The versatility of the lateral circumflex femoral artery branches can be exploited to include muscle, iliac bone, tendon, fascia, or nerve in extended designs. The anterolateral thigh flap is currently the frontline choice for head and neck reconstruction, including intraoral, mandibular-maxillary, tongue, and facial defects, and is gaining popularity in abdominal and pelvis reconstruction. It can also be used as a pedicled flap in phallus or perineum reconstruction. More recently, the flap has proved to be extremely useful in skin resurfacing and even functional reconstruction in traumatic wounds. This review summarizes the anatomy, planning, flap harvest, donor morbidity, and clinical applications of the anterolateral thigh flap. An algorithm is proposed that facilitates a clear, problem-based approach for the use of this versatile reconstructive option.

BACKGROUND: Frontobasal injury is a classic craniomaxillofacial fracture affecting the anterior cranial base. No data exist regarding the degree of frontobasal injury and associated midfacial fractures. The authors propose a classification of frontobasal and midface fractures involving the cranial base based on cadaveric experiments and comprehensive clinical experience. METHODS: An institutional review board-approved retrospective review was conducted on patients with frontobasal fractures from 1995 to 2005. Fractures were categorized by pattern, location, midfacial involvement (impure), and complications compiled. One hundred five cadaveric heads underwent blunt impact to the frontal bone and upper midface. Calvarial vault, cranial base, and midface fracture patterns were categorized. RESULTS: Three frontobasal fracture patterns were identified. Isolated linear cranial base fractures constitute type I. Vertical-linear fractures of the skull vault (frontal bone) occur in combination with base fractures, representing type II (vault and base). Comminution of the frontolateral skull vault and orbital roof in association with a linear base fracture constitute type III. Two hundred ninety patients were identified with 49 complications (cerebrospinal fistula, 24; and infectious 25). Type III (n = 159) had the highest complication rate (impure, 29 percent; pure, 17 percent), followed by type II (impure, 19 percent; pure, 5 percent). There is essentially no extension of midface fractures to the cranial vault. CONCLUSIONS: Frontobasal fractures have three unique and reproducible patterns based on vector, location, and force. This new classification scheme, paired with known patterns of midfacial injuries, assists in fully understanding frontofaciobasal injury and its complications. Overwhelmingly, impure type II and any type III fractures are associated with a high rate of complications and must be carefully managed.

Clinical detection of free flap failure lacks sensitivity. Failure is likely accompanied by altered gene expression; however, a genomic approach that identifies potential biomarkers and therapeutic targets has not been described. This study identifies genetic RNA expression alterations via microarray in a free flap failure animal model. A free tissue transfer rat model based on the inferior epigastric vessels was utilized. After microscopic anastomosis, the vein was occluded and RNA extracted from flap tissue of failure and control groups. Gene expression of 3 experimental and control group samples was assessed with the Affymetrix GeneChip Rat 230 v2.0 microarray. Quantitative reverse transcription polymerase chain reaction was performed on RNA of genes identified on an additional 6 experimental and 7 control group flaps. Eight hundred ninety of 28,000 genes had greater than 2-fold expression differences between experimental and controls. Student t test and 2-way analysis of variance filtering with equal variance identified 53 genes with statistically significant differences. Hierarchical clustering by gene ontology identified 4 genes with likely involvement in failure pathogenesis: RT1 class II, locus Bb, secreted frizzled-related protein 1, platelet/endothelial cell adhesion molecule, and Claudin 5. Validation performed by quantitative reverse transcription polymerase chain reaction revealed statistically significant expression alterations in locus Bb, platelet/endothelial cell adhesion molecule, and Claudin 5 of the failure group. Utilizing expression thresholds for test positivity, venous occlusion was predicted with 100% sensitivity and 86% specificity. Three highly sensitive and specific novel genes predictive of flap failure from venous occlusion were identified with altered expression in an animal model.

BACKGROUND: The technical success of facial composite tissue allotransplantation demands full understanding of superficial and deep perfusion for reliable microvascular transfer. Candidates with composite midface defects require an appreciation of the circulatory patterns to design a composite midface allotransplant. METHODS: External carotid vascular territories were evaluated in 10 cadavers to determine the reliability of facial soft-tissue flaps based on a single vascular pedicle. The right common carotid artery was injected with red latex and the left was injected with blue latex. Dual perfusion was confirmed by purple, following two-color mixing. Vascular pedicles included the superficial temporal, transverse facial, and facial arteries. In five additional cadavers, the midface segment was isolated by Le Fort III osteotomy after two-color latex injection with inclusion of the internal maxillary vascular pedicle. Cadavers were imaged with three-dimensional computed tomographic reconstructions following latex injection to confirm perfusion patterns. RESULTS: In soft-tissue facial flaps, unilateral carotid dominance was seen in the nasal dorsum and tip, confirming reliable supply by a single external carotid artery. In midface flaps, bilateral perfusion was seen in the maxilla. Ipsilateral perfusion was observed at the zygomaticomaxillary complex without any contralateral contribution. CONCLUSIONS: Dual soft-tissue perfusion was confirmed in most specimens at the nasal, central face, and maxilla. The inclusion of the maxilla in the design of a facial composite allotransplant demands bilateral vascular pedicles based on the internal maxillary arteries. The authors highlight a procurement strategy for design of such flaps.

BACKGROUND: Functional outcomes of lower extremity reconstruction compared with amputation have been evaluated. However, there are little comparative data among the different reconstructive options. With the recent increase in perforator flaps, we compared the functional outcomes of muscle and perforator flaps. METHODS: We conducted a retrospective review of 136 lower extremity trauma patients who underwent reconstruction with either a free muscle or perforator flap during a 7-year period. Forty-two of these patients completed the study. Patients answered the short musculoskeletal functional assessment form and supplemental questions. A physical therapist evaluated performance of physical tasks. Donor site sensation was measured with the pressure specified sensing device. Radiographic fracture union was evaluated by an orthopedic surgeon. RESULTS: Of the 42 patients enrolled, 20 had coverage with perforator flaps and 22 with muscle flaps. Quality of life and functional outcomes demonstrate no difference (p > 0.05). Ninety-three percent of patients would go through the limb salvage process to avoid amputation. Sensation at the donor site was diminished in all patients; however, the perforator flap donor site had more significant sensory loss (p = 0.005). Time to bony union (p = 0.51), union in the presence of infection (p = 0.85), and infection after flap (p = 0.87) was not related to flap type. CONCLUSION: Both muscle and perforator flaps provide vascularized coverage, which nourishes the fracture but muscle flaps pilfer a functional unit which may not be inconsequential in a patient trauma. This pilot study suggests that functional outcomes of perforator skin flaps are equal to muscle flaps and a larger prospective study is warranted.

BACKGROUND: Patients presenting with traumatic craniomaxillofacial fractures often have occult concomitant injuries. This study was designed to determine whether facial fracture patterns are associated with a particular constellation of concomitant head and neck injuries. METHODS: A retrospective review of 4786 consecutive patients diagnosed with maxillofacial fractures at a dedicated urban trauma center from 1998 to 2005 was conducted; maxillofacial fractures and cervical spine injuries were grouped by dividing the craniomaxillofacial skeleton and cervical spine into thirds. Univariate and multivariate logistic regression analyses were used to identify associations between facial fractures and other traumatic injuries. RESULTS: Among all patients with facial fractures, 461 (9.7 percent) also had cervical spine injuries and 2175 (45.5 percent) had associated head injuries. Fractures of the upper face were associated with increased likelihood of mid lower cervical spine injuries, severe intracranial injuries, and increased mortality rates. Unilateral mandible injuries were associated with an increased likelihood of having upper cervical spine injuries, whereas unilateral midface injuries were associated with basilar skull fractures and several intracranial injuries. Finally, bilateral midface injuries were associated with basilar skull fracture and death. CONCLUSIONS: Craniomaxillofacial fractures are commonly associated with head and cervical spine injuries that involve predictable patterns of force dispersion from the maxillofacial skeleton and transmission to the cranial vault and cervical spine. These results suggest that concomitant injuries should be investigated closely with distinct types of facial fractures.