In Situ Hydrolysis of Block Copolymers at the Water-Oil Interface.

In situ manipulation of the chemical composition of block copolymers at the fluid interfaces affords a route by which the interfacial tension, the packing of the copolymers, and the penetration of the blocks into the two liquids can be controlled. Here, a series of linear block copolymers of poly(solketal methacrylate-b-styrene) (PSM-b-PS) are used, converting hydrophobic PSM block into a hydrophilic glycerol monomethacrylate (GM) block, that results in a marked decrease in the liquid-liquid interfacial tension. The kinetics of the first-order hydrolysis reaction was analyzed by monitoring the time-dependent interfacial tension as a function of pH, polymer concentration, molecular weight, and composition. Fluorescence recovery after photobleaching (FRAP) was used to measure the in-plane dynamics of the copolymers before and after hydrolysis. This work provides insights into a quantitative pathway by which in situ interfacial reactions may be performed and monitored in real time, completely changing the interfacial activity of the molecule.

Pediatric Dog Bite Prevention: Are We Barking Up the Wrong Tree or Just Not Barking Loud Enough?

OBJECTIVES: The objectives of this study were (1) to evaluate dog bite-related injuries and associated medical documentation and (2) to compare these results with a study of dog bites from the same institution 10 years prior. METHODS: Data were retrospectively collected from a pediatric emergency department from July 2007 to July 2011 for patients treated for dog bites. These data were then compared with data from the same institution from 10 years prior. RESULTS: A total of 1017 bite injuries were treated (average, 254.25 bites/year), which represents a 25% increase compared with 10 years prior. Comparing the 1997 and 2007 to 2011 cohorts, patient demographics, bite rate among children less than 5 years old, rate of dog breed documentation, and setting of injury were similar. Dog breed was reported in 47% (95% confidence interval [CI], 40.2-53.9) and 41% (95% CI, 38.0-44.0) of cases, respectively, in the 2 cohorts. Bites to the craniofacial region were most common (face only reported for 1997: 43.2%; 95% CI, 36.4-50 versus 2007-2011: 66.1%; 95% CI, 63.2-69.0). In both cohorts, the child's home was the most frequent setting, accounting for 43% of bites (1997: 95% CI, 30.2-55.9 and 2007-2011: 95% CI, 39.3-46.7). CONCLUSIONS: Pediatric dog bites continue to occur frequently, and the associated factors did not change over the 10-year period: young age of child, bites to the craniofacial region, and dogs familiar to the child. Although accurate medical documentation of dog bites is a prerequisite to develop effective prevention strategies, current medical documentation of dog bites may be misguided.

Application of Laser Capture Microdissection to Craniofacial Biology: Characterization of Anatomically Relevant Gene Expression in Normal and Craniosynostotic Rabbit Sutures.

OBJECTIVE: Fusion of the cranial sutures is thought to depend on signaling among perisutural tissues. Mapping regional variations in gene expression would improve current models of craniosynostosis. Laser capture microdissection (LCM) isolates discrete cell populations for gene expression analysis. LCM has rarely been used in the study of mineralized tissue. This study sought to evaluate the potential use of LCM for mapping of regional gene expression within the cranial suture. DESIGN: Coronal sutures were isolated from 10-day-old wild-type and craniosynostotic (CS) New Zealand White rabbits, and LCM was used to isolate RNA from the sutural ligament (SL), osteogenic fronts (OF), dura mater, and periosteum. Relative expression levels for Fibroblast Growth Factor 2 (FGF2), Fibroblast Growth Factor Receptor 2 (FGFR2), Transforming Growth Factor Beta 2 (TGFß-2), Transforming Growth Factor Beta 3 (TGFß-3), Bone Morphogenetic Protein 2 (BMP-2), Bone Morphogenetic Protein 4 (BMP-4), and Noggin were determined using quantitative real-time PCR. RESULTS: A fivefold increase in TGFß2 expression was detected in the CS SL relative to wild type, whereas 152-fold less TGFß-3 was detected within the OF of CS animals. Noggin expression was increased by 10-fold within the CS SL, but reduced by 13-fold within the CS dura. Reduced expression of FGF2 was observed within the CS SL and dura, whereas increased expression of FGFR2 was observed within the CS SL. Reduced expression of BMP-2 was observed in the CS periosteum, and elevated expression of BMP-4 was observed in the CS SL and dura. CONCLUSIONS: LCM provides an effective tool for measuring regional variations in cranial suture gene expression. More precise measurements of regional gene expression with LCM may facilitate efforts to correlate gene expression with suture morphogenesis and pathophysiology.

Repair of a Complicated Calvarial Defect: Reconstruction of an Infected Wound With rhBMP-2.

BACKGROUND: Management of the previously infected craniofacial defect remains a significant clinical challenge, posing obstacles such as wound healing complications, lack of donor site availability, and predisposition to failure of the repair. Optimal therapy would reconstruct like with like, without donor site morbidity. The purpose of this study was to compare the efficacy of recombinant human bone morphogenetic protein-2 (rhBMP-2)-mediated bone regeneration with the current standard of autologous bone graft for repair of previously infected calvarial defects. METHODS: Nineteen adult New Zealand white rabbits underwent subtotal calvariectomy. Bone flaps were inoculated with Staphylococcus aureus and replanted. After 1 week of infection, bone flaps were removed, and wounds were debrided, followed by 10 days of antibiotic treatment. After 6 weeks, animals underwent scar debridement followed by definitive reconstruction in 1 of 4 groups: empty control (n = 3), vehicle control (buffer solution on absorbable collagen sponge [ACS], n = 3), autologous bone graft (n = 3), or rhBMP-2 repair (rhBMP-2/ACS, n = 10). Animals underwent computed tomography imaging at 0, 2, 4, and 6 weeks postoperatively, followed by euthanization and histological analysis. Percent healing was determined by 3-dimensional analysis. A (time × group) 2-way analysis of variance was performed on healing versus treatment group and postoperative time. RESULTS: At 6 weeks postoperatively, rhBMP-2/ACS and autologous bone graft resulted in 93% and 68% healing, respectively, whereas the empty and vehicle control treatment resulted in 27% and 26% healing (P < 0.001). Histologically, compared to autologous bone graft, bone in the rhBMP-2/ACS group was more cellular and more consistently continuous with wound margins. CONCLUSIONS: The rhBMP-2 therapy is effective in achieving radiographic coverage of previously infected calvarial defects.

Severe Pediatric Midface Trauma: A Prospective Study of Growth and Development.

Severe pediatric facial trauma is characterized by multiple, comminuted, and unstable fractures, frequently necessitating operative intervention. Disruption of facial growth is a primary concern in the long-term sequelae of such conditions. Children suffering from midface fractures were followed over time in a long-term growth and development study. Lateral cephalograms at longest-term follow-up were traced, digitized, and averaged. Seven landmarks of the midface (A point, ANS, orbitale, bridge of nose, distal U6, upper lip, stomion superius) were identified for comparative measurements with age and sex-matched superimposed Bolton norms as controls. Differences in x and y axes between test and control metrics were measured. Clinical significance was defined as a 2-mm discrepancy from the norm. Statistical significance for each patient was determined using t tests of the x and y arrays of patient values versus normal controls. Seven patients met the inclusion criteria with mean age of 8.9 years at the time of injury. Mean cephalometric follow-up was 4.6 years (range 2-10 years). Six out of 7 patients (86%) showed clinically significant impairment in growth in horizontal (29%), vertical (29%), or both planes (29%). T Tests confirmed statistical significance (P ≤ 0.05) for all clinically significant differences. Mean deficiency in growth for all landmarks was 3.7  mm (range -4.0 to 13.7  mm) in the x axis and 2.9  mm (range -1.1 to 8.8  mm) in the y axis. Severe pediatric midface trauma often results in compromised bone growth and permanent facial deformity. New methodologies of management that better allow for growth are needed.

BMP-2-regenerated calvarial bone: a biomechanical appraisal in a large animal model.

Recombinant human bone morphogenetic protein-2 (rhBMP-2) is gaining popularity in craniofacial applications. Calvarial defects are, under normal circumstances, subjected to only minimal levels of the biomechanical stresses known to play an important role in osteogenesis, yet regenerated calvarial bone must be capable of withstanding traumatic forces such that the underlying neurocapsule is protected. The aim of this study is to, for the first time, assess the biomechanical properties of calvarial bone regenerated with derivations of a commercially available rhBMP-2-based system. Standardized calvarial defects were created in 23 adult male canines. These defects were treated with rhBMP-2 on one of several carriers. After 24 weeks, the biomechanical properties of the rhBMP-2-generated bone were compared to those of controls with a modified punch-out test (Bluehill 2; Instron, Norwood, Mass) and compared using a paired nonparametric analyses (SPSS, 17.0, Chicago, Ill). In a previously published report, defects across all the rhBMP-2 therapy groups were observed to have a mean rate of 99.5% radio-opacity at 24 weeks indicating nearly full bony coverage of the calvarial defect (compared to 32.7% in surgical controls). For ultimate load, ultimate energy, and first peak energy, there were significant differences (P<0.05) with the control native bone having more robust biomechanical properties than the rhBMP-2-generated bone. We conclude from these findings that rhBMP-2-generated calvarial bone is significantly less protective against trauma than native bone at 6 months. Further investigation is required to assess the efficacy of rhBMP-2 in healing calvarial defects in the longer term.

Bone morphogenetic protein 2­mediated mandible reconstruction successfully heals bony defects but inhibits concurrent inferior alveolar nerve grafting: a rabbit experimental model.

BACKGROUND: Bone morphogenetic protein 2 (BMP-2) has been used to reconstruct mandibular defects. An elegant addition to this reconstruction method would be incorporation of a nerve graft wrapped in a BMP-2 carrier to reconstitute the inferior alveolar nerve (IAN) and restore sensation to the lower face. We developed a rabbit model to determine the effect BMP-2 has on nerve regeneration following neurorrhaphy. METHODS: An inferior border mandibulectomy was created in 16 adult New Zealand white rabbits. The IAN was protected, divided, and repaired with either primary neurorrhaphy or reverse autografts. Bone defects were treated with no treatment controls (n = 2), absorbable collagen sponge (ACS) (vehicle controls) (n = 7), and ACS soaked in BMP-2 (treatment group) (n = 7). Animals underwent computed tomography (CT) 2 days and 6 weeks postoperatively. The percent bone defect healing was calculated using Amira 3D imaging software. At 6 weeks, IANs were harvested mesial to the reconstruction and were evaluated with toluidine blue histology to identify myelinated axons. Reconstructed mandible segments were evaluated with micro-CT and hematoxylin-eosin histology. RESULTS: Bone morphogenetic protein 2-treated animals demonstrated significantly more bone healing than did the ACS and empty defect groups (82%, 38%, 44%, respectively; P < 0.01). One hundred percent of ACS-treated nerves (n = 4) demonstrated axon regrowth, whereas only 25% of BMP-2-treated nerves (n = 4) did. Micro-CT and histology showed BMP-2 caused bone growth around the IAN, but regenerated bone infiltrated the repair site and created a physical barrier to axon growth. CONCLUSIONS: Bone morphogenetic protein 2 can successfully heal bone defects in the rabbit mandible, but ectopic bone growth can inhibit IAN recovery after repair. Level of Evidence: Not gradable.

Intraoperative high-dose epinephrine infiltration in cleft palate repair.

OBJECTIVE: Local infiltration of epinephrine before surgical procedures is a well-accepted technique to promote vasoconstriction. Typically, the dose of epinephrine is limited by the co-administration of local anesthetic as well as the risk for arrhythmogenesis and hemodynamic changes. In addition, some controversy exists regarding the acceptable dose of epinephrine given to children. This retrospective review examines the use and safety of "high-dose" epinephrine in palatoplasty at our cleft-craniofacial center. DESIGN: A retrospective review of epinephrine use in primary palatoplasty at a tertiary children's hospital from 2003 to 2007 was performed. Operative and anesthetic records were reviewed for hypertension (systolic blood pressure, >120 or diastolic blood pressure, >70) and tachycardia (>190 beats per min) as defined by the American Heart Association guidelines, as well as dysrhythmias, intraoperative complications, and postoperative complications. RESULTS: A total of 102 patients who underwent consecutive primary palatoplasties performed by a single surgeon were identified. After the induction of anesthesia and before incision, the patients received an initial epinephrine infiltration (without local anesthetic) up to a maximum 10 µg/kg. The average total dose of epinephrine administered during palatoplasty was 12.8 µg/kg (range, 3.2-75.0 µg/kg). Doses up to a maximum of 10 µg/kg were administered as needed at 30-minute intervals. No instances of clinically unstable tachycardia or hypertension occurred. A total of 21.6% of the patients (22/102) experienced an instance of hypertension, and only 13.7% of these (14/102) were related to epinephrine administration. One (1%) postoperative fistula was identified. CONCLUSIONS: Locally infiltrated high-dose epinephrine during palatoplasty can be safely used as a means of vasoconstriction. Doses reaching a maximum of 10 µg/kg, administered as needed at 30-minute intervals, do not seem to be a significant risk for hemodynamic instability, intraoperative complications, or postoperative complications.

Plerixafor for pathogen-agnostic treatment in murine thigh infection and zebrafish sepsis.

Plerixafor is a CXCR4 antagonist approved in 2008 by the FDA for hematopoietic stem cell collection. Subsequently, plerixafor has shown promise as a potential pathogen-agnostic immunomodulator in a variety of preclinical animal models. Additionally, investigator-led studies demonstrated plerixafor prevents viral and bacterial infections in patients with WHIM syndrome, a rare immunodeficiency with aberrant CXCR4 signaling. Here, we investigated whether plerixafor could be repurposed to treat sepsis or severe wound infections, either alone or as an adjunct therapy. In a Pseudomonas aeruginosa lipopolysaccharide (LPS)-induced zebrafish sepsis model, plerixafor reduced sepsis mortality and morbidity assessed by tail edema. There was a U-shaped response curve with the greatest effect seen at 0.1 µM concentration. We used Acinetobacter baumannii infection in a neutropenic murine thigh infection model. Plerixafor did not show reduced bacterial growth at 24 h in the mouse thigh model, nor did it amplify the effects of a rifampin antibiotic therapy, in varying regimens. While plerixafor did not mitigate or treat bacterial wound infections in mice, it did reduce sepsis mortality in zebra fish. The observed mortality reduction in our LPS model of zebrafish was consistent with prior research demonstrating a mortality benefit in a murine model of sepsis. However, based on our results, plerixafor is unlikely to be successful as an adjunct therapy for wound infections. Further research is needed to better define the scope of plerixafor as a pathogen-agnostic therapy. Future directions may include the use of longer acting CXCR4 antagonists, biased CXCR4 signaling, and optimization of animal models.

Precise control of osteogenesis for craniofacial defect repair: the role of direct osteoprogenitor contact in BMP-2-based bioprinting.

BACKGROUND: Success with bone morphogenetic protein-2 (BMP-2) has been widely reported in the osseous reconstruction of large calvarial defects. These efforts have required enormous doses of BMP-2 and are not sufficiently refined to facilitate the detail-oriented repair required for intricate craniofacial structures. We have previously shown that inkjet-based bioprinting technologies allow for precisely customized low-dose protein patterns to induce spatially regulated osteogenesis. Here, we investigate the importance of direct contact between bioprinted BMP-2 and the dura mater (a source of osteoprogenitors) in mediating calvarial healing. METHODS: Five-millimeter osseous defects were trephinated in mouse parietal bones (N=8). Circular acellular dermal matrix (ADM) implants were prepared such that 1 semicircle of 1 face per implant was printed with BMP-2 bio-ink. These implants were then placed ink-toward (N=3) or ink-away (N=5) from the underlying dura mater. After 4 weeks, osteogenesis was assessed in each of the 4 possible positions (BMP-2-printed area toward dura, BMP-2-printed area away from dura, unprinted area toward dura, and unprinted area away from dura) by faxitron. RESULTS: The BMP-2-printed portion of the ADM generated bone covering an average of 66.5% of its surface area when it was face-down (printed surface directly abutting dura mater). By comparison, the BMP-2-printed portion of the ADM generated bone covering an average of only 21.3% of its surface area when it was face-up (printed surface away from dura). Similarly, the unprinted portion of the ADM generated an average of only 18.6% osseous coverage when face-down and 18.4% when face-up. CONCLUSIONS: We have previously shown that inkjet-based bioprinting has the potential to significantly enhance the role of regenerative therapies in craniofacial surgery. This technology affords the precise control of osteogenesis necessary to reconstruct this region's intricate anatomical architecture. In the present study, we demonstrate that direct apposition of BMP-2-printed ADM to a source of osteoprogenitor cells (in this case dura mater) is necessary for bio-ink-directed osteogenesis to occur. These results have important implications for the design of more complex bioprinted osseous structures.

Novel model of calvarial defect in an infected unfavorable wound: reconstruction with rhBMP-2. Part II.

BACKGROUND: Animal models of bone reconstruction have shown recombinant human bone morphogenetic protein 2 (rhBMP-2) to be an effective therapy in the acute calvarial defect wound. The purpose of this study was to compare the effectiveness of rhBMP-2 in a rabbit model of an unfavorable scarred calvarial wound with the criterion standard of autograft. METHODS: Nineteen adult New Zealand white rabbits underwent subtotal calvariectomy. After 6 weeks of healing and normal scar formation, these animals underwent reoperation for scar debridement and assignment to 1 of 4 therapeutic groups. Animals were assigned to an empty control group (no treatment, n = 3), vehicle control group (neutral buffered solution on an absorbable collagen sponge [ACS], n = 3), surgical control group (cryopreserved autograft, n = 3), or an experimental treatment group (rhBMP-2 on an ACS, n = 10). All animals underwent computed tomography imaging at 0, 2, 4, and 6 weeks after secondary reconstructive surgery. At 6 weeks, all animals were killed, and the defects were examined histologically. Percentage of healing of each defect was determined, and a 4 × 3 mixed-model analysis of variance was performed on healing as a function of time and therapy. RESULTS: Based on measures of defect radiopacity, the treatment group (rhBMP-2/ACS) and surgical control group (autograft) were statistically equivalent with 98% and 83% healing, respectively, at 6 weeks. The empty control and vehicle control groups were inferior to the treatment group (rhBMP-2/ACS) and surgical control (autograft) groups at each timepoint (P < 0.05). Histologically, bone in the surgical control (autograft) group was less trabecular and less cellular than the bone formed in the experimental treatment group (rhBMP-2/ACS). CONCLUSIONS: Compared with historical controls, rhBMP-2 therapy was as effective in reconstructing calvarial defects in the unfavorable scarred wound as in the acute favorable calvarial wound. When compared with cryopreserved autograft, rhBMP-2-regenerated bone showed equal defect coverage and similar bone thickness with varying bony architecture.

Custom porous polyethylene implants for large-scale pediatric skull reconstruction: early outcomes.

BACKGROUND AND PURPOSE: Some of the most problematic craniofacial injuries in pediatric plastic surgery are large calvarial defects in children who have passed the age of maximal dural osteogenic potential and yet are too young to yield split calvarial grafts. Porous polyethylene (Medpor; Porex) is an alloplastic material that can be customized to precisely match a cranial defect. We present a clinical series that demonstrates successful use of porous polyethylene cranioplasties in large pediatric cranial defects. METHODS: From 2007 to 2009, 9 pediatric patients underwent custom-made porous polyethylene cranioplasties for large calvarial defects. Descriptive statistical analyses were performed on the cause of the defects, time to cranioplasty, size of defect, reconstruction technique, and postoperative healing. RESULTS: A total of 5 boys and 4 girls, with a mean age of 6.8 years, underwent 9 cranioplasties incorporating custom porous polyethylene implants. Initial pathologic findings included 7 patients with traumatic brain injuries, 1 patient with intractable seizures, and 1 patient with brain cancer. Initially, each patient had a craniectomy followed by replacement of the frozen bone "flap." All patients experienced either infection or resorption of the bone leading to a permanent defect. The mean defect size was 152 cm. The mean delay between the removal of failed bone "flap" and the final implant cranioplasty was 6.8 months. At the last follow-up, which averaged 3.6 months, all patients had stable wounds with acceptable cranial contour. CONCLUSIONS: For pediatric large-scale calvarial defects, custom-made porous polyethylene implants can be safely used for cranioplasty. Tissue expansion and acellular dermal matrix were useful tools to help augment the soft tissues of the scalp before cranioplasty to prevent complications of implant extrusion and wound breakdown.

The Role of Energy-Based Devices in Male Body Contouring.

Energy-based devices extend the indications of traditional procedures in male body contouring. Devices currently available in this space may be noninvasive or minimally invasive. These devices use heat to destroy fat or tighten soft tissue and electromagnetic energy to build muscle mass. Thoughtful deployment of these technologies in isolation or in combination with each other or more traditional approaches can improve outcomes in male body contouring without an increase in scar burden. Patient selection and education are essential in maximizing satisfaction with these procedures.

Outcomes in pediatric facial fractures: early follow-up in 177 children and classification scheme.

A comprehensive study of adverse outcomes after pediatric facial fractures has not been published. This study aimed to determine the incidence and classify adverse outcomes after facial fractures in children while reporting our early results. A retrospective chart review was performed on facial fracture patients identified in the Craniofacial Trauma Database of the Children's Hospital of Pittsburgh and seen in follow-up from 2003 to 2007. An Adverse Outcome Classification Scheme was developed: type 1, outcomes resulting from the fracture; type 2, outcomes resulting from fracture treatment; and type 3, outcomes resulting from the interaction between the fracture, its treatment, and subsequent growth and development. Fisher exact or χ analyses were completed. A total of 177 pediatric facial fracture patients were identified with 13.3 months of average follow-up. Mean age was 9.8 years (range, 0.4-18.7 y). Of these patients, 41.8% underwent surgery and 57 patients (32.2%) had adverse outcomes (type 1, 14.1%; type 2, 11.3%; and type 3, 15.8%); 26.3% of these had multiple adverse outcomes. Isolated fractures resulted in fewer adverse outcomes and fewer multiple adverse outcomes compared with combined fractures (26.6% versus 45.3%, P = 0.015; 4% versus 18.9%, P = 0.002). Patients treated operatively exhibited more types 1, 2, and 3 and multiple adverse outcomes compared to those treated conservatively (P < 0.01). In our pediatric cohort, 32.2% of patients had an adverse outcome. With longer follow-up and growth and development studies, we will likely see an increase in the incidence of type 3 adverse outcomes. We recommend, whenever possible, conservative treatment of pediatric facial fractures.

Acellular dermal matrix in palatoplasty.

The primary goal of palatoplasty is to allow normal speech through the correction of velopharyngeal incompetence. Failure to accomplish a tension-free, watertight closure predisposes the palatoplasty patient to postoperative fistula formation. Fistulas may in turn contribute to velopharyngeal incompetence. Reported fistula rates vary widely, ranging from 0% to greater than 70%; recurrence rates after attempted repair approach 65% in some series. These lesions therefore represent a significant clinical burden. Acellular dermal matrix materials have been introduced into various phases of palatoplasty as a strategy to augment repairs and minimize postoperative fistula formation, as well as repair fistulas when they do occur. In this article, the authors review the existing literature regarding acellular dermal matrix in palatoplasty and describe their own algorithm and results for primary and secondary palatoplasty in which acellular dermal matrix plays a central role.

Autologous bone grafting with adjunctive use of acellular dermal matrix for alveolar cleft defects: early outcomes.

BACKGROUND AND PURPOSE: Alveolar bone grafting remains the standard for alveolar cleft repair. Compromised oral and/or nasal closure may impede healing and result in graft failure or persistent fistulae. Incorporating acellular dermal matrix into these repairs may protect the bone graft during mucosal healing by providing an additional layer of soft tissue coverage. METHODS: A retrospective review of alveolar bone grafts undertaken at our cleft-craniofacial center from 2005 to 2007 was performed. The use of acellular dermal matrix for nasal and/or oral lining augmentation was determined. A minimum 3 months' follow-up was required for inclusion. Outcomes included (1) mucosal disruption, (2) time to complete mucosal healing, (3) bone graft exposure, (4) postoperative bone graft incorporation using the Chelsea scale, and (5) canine eruption through the graft site. RESULTS: In total, 35 patients were included. Of those, 15 patients (four girls, 11 boys; seven Veau III, eight Veau IV) received acellular dermal matrix for mucosal augmentation (five nasal, one oral, nine nasal and oral lining). Average age at surgery was 10 years (range, 9 to 16 years). Average follow-up was 23 months (range, 3 to 35 months). Mucosal disruption occurred in 20% of the acellular group and in 30% of the control group (p=nonsignificant). Complete mucosal healing was achieved at an average of 4 weeks (range, 1 to 14 weeks) in the acellular dermal matrix group versus 4 weeks (range, 2 to 11 weeks) in the control group (p=nonsignificant). Exposure of bone graft occurred in 0% of the acellular dermal matrix group and in 30% of the control group (p=.016). The Chelsea scale demonstrated no significant radiographic difference in postoperative bone graft incorporation between the acellular dermal matrix and control groups. Canine eruption through the graft site was similar for both groups. CONCLUSIONS: These data support the conclusions that using acellular dermal matrix to augment nasal/oral mucosal lining in alveolar bone grafts (1) does not increase mucosal disruption or time to complete healing, (2) prevents postoperative bone graft exposure, and (3) appears to have no negative effect on postoperative bone graft incorporation or canine eruption through the graft site.

Characterization of transplanted green fluorescent protein+ bone marrow cells into adipose tissue.

Following transplantation of green fluorescent protein (GFP)-labeled bone marrow (BM) into irradiated, wild-type Sprague-Dawley rats, propagated GFP(+) cells migrate to adipose tissue compartments. To determine the relationship between GFP(+) BM-derived cells and tissue-resident GFP(-) cells on the stem cell population of adipose tissue, we conducted detailed immunohistochemical analysis of chimeric whole fat compartments and subsequently isolated and characterized adipose-derived stem cells (ASCs) from GFP(+) BM chimeras. In immunohistochemistry, a large fraction of GFP(+) cells in adipose tissue were strongly positive for CD45 and smooth muscle actin and were evenly scattered around the adipocytes and blood vessels, whereas all CD45(+) cells within the blood vessels were GFP(+). A small fraction of GFP(+) cells with the mesenchymal marker CD90 also existed in the perivascular area. Flow cytometric and immunocytochemical analyses showed that cultured ASCs were CD45(-)/CD90(+)/CD29(+). There was a significant difference in both the cell number and phenotype of the GFP(+) ASCs in two different adipose compartments, the omental (abdominal) and the inguinal (subcutaneous) fat pads; a significantly higher number of GFP(-)/CD90(+) cells were isolated from the subcutaneous depot as compared with the abdominal depot. The in vitro adipogenic differentiation of the ASCs was achieved; however, all cells that had differentiated were GFP(-). Based on phenotypical analysis, GFP(+) cells in adipose tissue in this rat model appear to be of both hematopoietic and mesenchymal origin; however, infrequent isolation of GFP(+) ASCs and their lack of adipogenic differentiation suggest that the contribution of BM to ASC generation might be minor.

Calcium aluminate, RGD-modified calcium aluminate, and beta-tricalcium phosphate implants in a calvarial defect.

Calcium aluminate (CaAl), arginine-glycine-aspartic acid-modified CaAl, and beta-tricalcium phosphate (TCP) implants were studied in a rat calvarial critical-sized defect model. The rates of newly formed bone and osteointegration were measured using 3 different methods: radiography, micro-computed tomography, and histologic examination. After 4 weeks, there was no new bone formed and no signs of osteointegration into the skull bone in the CaAl or arginine-glycine-aspartic acid-modified CaAl groups, and thick fibrous capsules were visible around the whole circumference of the implants in both groups. In the beta-TCP group, neovascularization of the implant was observed, which is consistent with the early phase of new bone formation. In addition, in the beta-TCP group, signs of implant integration into the host tissue were evident at 4 weeks. There was no soft tissue reaction around the beta-TCP implant. These observations suggest that more specific adhesion peptides may be needed to activate the bioinert CaAl implant and promote bone formation in the craniofacial skeleton.

The reverse sural flap: modifications to improve efficacy in foot and ankle reconstruction.

The aim of this work is to evaluate the efficacy of the reverse sural flap in covering defects in the foot and ankle region when certain technical modifications are employed. We provide a retrospective review of 32 consecutive reverse sural flaps for foot and ankle defects, and compare the technique and results with other reports. There were 23 fasciocutaneous flaps, 7 fascial flaps, and 2 tissue-expanded flaps. Four flaps (12.5%) suffered significant flap loss, and 4 patients had delayed healing.Several modifications are suggested to increase the versatility of the sural flap in covering foot and ankle defects, including preserving the mesentery connecting the sural nerve to the deep fascia, inclusion of skin of the upper third of the leg, limiting pedicle width to 2 cm with preservation of a tongue-like skin process all along its length, and generous release of the fascia over the peroneal compartment. In addition, we describe the use of tissue expanded sural flaps.