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Aging in humans and animals is associated with gradual and variable changes in some cognitive functions, but what causes them and explains individual variations remains unclear. Hydration decreases with aging but whether dehydration contributes to cognitive dysfunction is not known. The brain hydration of aging mice was determined by colloidosmotic-pressure titration. Dehydration increased with age from ∼76 mmHg at 6 weeks to ∼105 mmHg at 40 weeks, or a progressive ∼10 percent loss of brain water but seemed to level off afterward. When we adjusted dehydration in hippocampal slices of

Background Traumatic spinal cord injury (SCI) is a major worldwide cause of mortality and disability with limited treatment options. Previous research applying controlled negative pressure to traumatic brain injury in rat and swine models resulted in smaller injuries and more rapid recovery. Objective To examine the effects of the application of a controlled vacuum (mechanical tissue resuscitation [MTR]) to SCI in a rat model under several magnitudes of vacuum. Methods Controlled contusion SCIs were created in rats. Vacuums of -50 and -75 mm Hg were compared. Analysis included open-field locomotor performance, magnetic resonance imaging (in vivo T2, ex vivo diffusion tensor imaging and fiber tractography), and histological assessments. Results MTR treatment significantly improved the locomotor recovery from a Basso, Beattie, and Bresnahan score of 7.8 ± 1.9 to 11.4 ± 1.2 and 10.7 ± 1.9 at -50- and -75-mm Hg pressures, respectively, 4 weeks after injury. Both pressures also reduced fluid accumulations > 10% by T2-imaging in SCI sites. The mean fiber number and mean fiber length were greater across injured sites after MTR treatment, especially with treatment with -50 mm Hg. Myelin volume was increased significantly by 60% in the group treated with -50 mm Hg. Conclusion MTR of SCI in a rat model is effective in reducing edema in the injured cord, preserving myelin survival, and improving the rate and quantity of functional recovery. Abbreviations BBB, Basso, Beattie, and BresnahanDTI, diffusion tensor imagingFA, fractional anisotropyMTR, mechanical tissue resuscitationMTR50, mechanical tissue resuscitation with 50-mm Hg subatmospheric pressureMTR75, mechanical tissue resuscitation with 75-mm Hg subatmospheric pressureROI, region of interestSCI, spinal cord injury.

The interstitial myocardial matrix is a complex and dynamic structure that adapts to local fluctuations in pressure and actively contributes to the heart's fluid exchange and hydration. However, classical physiologic models tend to treat it as a passive conduit for water and solute, perhaps because local interstitial regulatory mechanisms are not easily accessible to experiment in vivo. Here, we examined the interstitial contribution to the fluid-driving pressure ex vivo. Interstitial hydration potentials were determined from influx/efflux rates measured in explants from healthy and ischemia-reperfusion-injured pigs during colloid osmotic pressure titrations. Adaptive responses were further explored by isolating myocardial fibroblasts and measuring their contractile responses to water activity changes in vitro. Results show hydration potentials between 5 and 60 mmHg in healthy myocardia and shifts in excess of 200 mmHg in edematous myocardia after ischemia-reperfusion injury. Further, rates of fluid transfer were temperature-dependent, and in collagen gel contraction assays, myocardial fibroblasts tended to preserve the micro-environment's hydration volume by slowing fluid efflux rates at pressures above 40 mmHg. Our studies quantify components of the fluid-driving forces in the heart interstitium that the classical Starling's equation does not explicitly consider. Measured hydration potentials in healthy myocardia and shifts with edema are larger than predicted from the known values of hydrostatic and colloid osmotic interstitial fluid pressures. Together with fibroblast responses in vitro, they are consistent with regulatory mechanisms that add local biological controls to classic fluid-balance models.

Poly(glycerol sebacate) (PGS)/nanohydroxyapatite (nHA) composites were assessed to develop new materials for closure via tissue transport for nonhealing defects (e.g., cleft palate and large skin wounds). The elastic shape memory polymer, PGS, was reinforced with nHA at 3 and 5% loading to increase the mechanical properties compared with the undoped PGS. Differential scanning calorimetry (DSC) was utilized to identify a glass transition temperature (Tg ) of -25°C. X-ray diffraction demonstrated a reduction in the amorphous nature of the material. The Fourier transform infrared photoacoustic spectral (FTIR-PAS) data showed decreased CO bonding and increased hydrogen bonding with increased nHA incorporation. Composites exhibited Young's moduli in the range of 0.25-0.5 MPa and tensile strength of 1.5-3 N. No significant difference in extension to break (∼50 mm) with addition of nHA was observed. The elastic modulus significantly increased for 5% PGS/nHA compared to 0 and 3% PGS/nHA and tensile strength significantly increased for 3% PGS/nHA compared to 0 and 5% PGS/nHA. Degradation of 5% nHA/PGS significantly increased during the second week compared to PGS 0 and 3% PGS/nHA. The accelerated degradation for 5% PGS/nHA coupled with decreased flexibility and tensile strength implies an interruption in crosslinking. By maintaining flexibility and extension while increasing tensile strength, the 3% PGS/nHA doped satisfied the force range desired for closure of soft tissue defects. Based on this work, PGS with 3% nHA shape memory polymers should serve as a good candidate for closure of nonhealing soft tissues. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1366-1373, 2016.

Background and Aim Myocardial ischemia-reperfusion injury is known to trigger an inflammatory response involving edema, apoptosis, and neutrophil activation/accumulation. Recently, mechanical tissue resuscitation (MTR) was described as a potent cardioprotective strategy for reduction of myocardial ischemia-reperfusion injury. Here, we further describe the protective actions of MTR and begin to define its therapeutic window. Methods A left ventricular, free-wall ischemic area was created in anesthetized swine for 85 minutes and then reperfused for three hours. Animals were randomized to two groups: (1) untreated controls (Control) and (2) application of MTR that was delayed 90 minutes after the initiation of reperfusion (D90). Hemodynamics and regional myocardial blood flow were assessed at multiple time points. Infarct size and neutrophil accumulation were assessed following the reperfusion period. In separate cohorts, the effect of MTR on myocardial interstitial water (MRI imaging) and blood flow was examined. Results Both groups had similar areas at risk (AAR), hemodynamics, and arterial blood gas values. MTR, even when delayed 90 minutes into reperfusion (D90, 29.2 ± 5.0% of AAR), reduced infarct size significantly compared to Controls (51.9 ± 2.7%, p = 0.006). This protection was associated with a 33% decrease in neutrophil accumulation (p = 0.047). Improvements in blood flow and interstitial water were also observed. Moreover, we demonstrated that the therapeutic window for MTR lasts for at least 90 minutes following reperfusion. Conclusions This study confirms our previous observations that MTR is an effective therapeutic approach to reducing reperfusion injury with a clinically useful treatment window. doi: 10.1111/jocs.12580 (J Card Surg 2015;30:659–667)

The aim of this study was to demonstrate that multi-wall carbon nanotubes can be functionalised with antibodies to group A streptoccocus (GAS) for targeted photothermal ablation of planktonic and biofilm residing bacteria.Antibodies for GAS were covalently attached to carboxylated multi-wall carbon nanotubes and incubated with either planktonic or biofilm GAS. Bacterium was then exposed to 1.3 W/cm(2) of 800 nm light for 10-120 s, and then serially diluted onto agar plates from which the number of colony forming units was determined. Photothermal ablation of GAS on the surface of full thickness ex vivo porcine skin and histological sectioning were done to examine damage in adjacent tissue.Approximately 14% of the GAS antibody-functionalised nanotubes attached to the bacterium, and this amount was found to be capable of inducing photothermal ablation of GAS upon exposure to 1.3 W/cm(2) of 800 nm light. Cell viability was not decreased upon exposure to nanotubes or infrared light alone. Compared to carboxylated multi-wall carbon nanotubes, antibody-labelled nanotubes enhanced killing in both planktonic and biofilm GAS in conjunction with infrared light. Analysis of GAS photothermally ablated in direct contact with ex vivo porcine skin shows that heat sufficient for killing GAS remains localised and does not cause collateral damage in tissue adjacent to the treated area.The results of this study support the premise that carbon nanotubes may be effectively utilised as highly localised photothermal agents with the potential for translation into the clinical treatment of bacterial infections of soft tissue.

Purpose of review To present the current surgical options for minimally invasive surgery for treatment of craniosynostosis. Recent findings Minimally invasive procedures are well tolerated treatment options for patients with craniosynostosis. Suturectomy and helmet therapy is a treatment option for scaphocephaly with minimal blood loss and length of hospital stay. Spring-mediated cranioplasty is, in addition, a well tolerated and effective treatment option for scaphocephaly. Summary In patients with multiple suture craniosynostosis, surgical techniques that utilize spring-assisted surgery can provide decreased morbidity with better bone formation made available for a second operation. Continued basic science research and clinical studies will expand the use and provide further minimally invasive procedures to infants with craniosynostosis.

Conventional collagen-based heart valves eventually fail because of insufficient replacement of graft material by host tissue. In this study, type I collagen was blended with silk fibroin and the synthetic elastic polymer poly (glycerol-sebacate) (PGS) in varying proportions to create multifunctional electrospun nanofibrous materials tailored for use as endovascular scaffolds such as heart valve replacement. Depending on the blended material the elastic moduli ranged from 2.3 to 5.0 Mpa; tensile stresses ranged from 0.8 to 1.5 Mpa; and strains ranged from 30% to 70%. Electrospun materials with a weight ratio of 4.5:4.5:1 (collagen, fibroin, and PGS) (termed PFC mats) were the most similar to native heart valves. In vitro degradation of PFC mats was 0.01% per week. Endothelial cells adhered to, proliferated, and formed cell-cell junctions on PFC mats. Compared with collagen hydrogels and electrospun collagen mats respectively 220-290% less platelet adhesion was observed for PFC mats. The study demonstrates that PFC material has superior mechanical properties, low degradation, and reduced thrombogenic potential and suggests that further investigation of this biomaterial for cardiovascular applications is warranted.

Thermal injury disrupts fluid homeostasis and hydration, affecting hemodynamics and local interstitial fluid-driving forces, leading rapidly to edema. This study explores local mechanisms in vivo, after deep partial-thickness burns in the dermal matrix. Heat-damaged skin was obtained from pig corpses, byproducts of unrelated burn treatment protocols approved by the Institutional Animal-Care-and-Use Committee. Hydration potential and flow rates were measured by osmotic stress techniques at 4 and 37 °C, and collagen folding/unfolding was examined by differential scanning calorimetry and diffusion tensor magnetic resonance imaging. Kinetic and equilibrium hydration parameters differed in heat-damaged and undamaged skin; the mean hydration potential and initial flow rates of damaged skin were negative at 37 but positive at 4 °C, in contrast to the positive mean at either temperature of explants taken from undamaged skin sites on the same animals. After subatmospheric pressure treatment (125 mmHg), parameters in damaged reversed to values similar to those of undamaged, whereas the proportion of folded collagen and unidirectional resistance to water diffusion increased. Together, results support interfacial rather than colloidosmotic fluid transfer mechanisms in burns and confirm in vivo the relevance of collagen folding/unfolding, further suggesting collagen structural transitions as potential therapeutic targets and models for engineered biomimetic materials.

Background and Aim Reperfusion injury is a complex inflammatory response involving numerous mechanisms and pathways. Mechanical tissue resuscitation is a newly described therapeutic strategy that reduces reperfusion injury. This study further investigates potential mechanisms for the protective effects of mechanical tissue resuscitation while utilizing a bio-absorbable matrix. Methods Anesthetized swine were subjected to 80 minutes of coronary ischemia and three hours of reperfusion. An absorbable matrix was used to cover the ischemic-reperfused myocardium and apply the mechanical tissue resuscitation (−50 mmHg) throughout reperfusion. Infarct size, myocardial blood flow (microspheres), apoptosis, edema, and hemodynamics were analyzed. Results Both control and treated groups displayed similar hemodynamics and physiologic parameters. Mechanical tissue resuscitation significantly reduced early infarct size (16.6 ± 3.8% vs. 27.3 ± 2.5% of area at risk, p

The aim in this study was to describe the safety and efficacy of vacuum-assisted closure (VAC) in patients with complex cranial wounds with extensive scalp, bone, and dural defects who were not candidates for immediate free tissue transfer. Five patients (4 men and 1 woman) ages 24–73 years with complex cranial wounds were treated with VAC at Wake Forest Baptist Medical Center. Etiologies included trauma, squamous cell carcinoma, and malignant meningioma. Cutaneous wound defects measured as large as 15 cm in diameter. Four of the 5 patients had open skull defects with concomitant dural defects, and 1 patient had dural dehiscence. After surgical debridement, all 5 patients were treated with the direct application of a VAC device to a reapproximated dura mater (1 patient), to a pericranial flap (1 patient), or to a regenerative tissue matrix overlying CNS tissue (3 patients). In all cases involving open cranial wounds, the VAC device promoted granulation tissue formation over the dural substitute, prevented CSF leakage, and kept the wounds free from local infection. The duration of VAC therapy ranged from 16 to 91 days. Although VAC therapy was intended as a temporary measure until these patients could be stabilized for larger tissue transfer procedures or they succumbed to their primary pathology, 1 patient had a successful skin graft following VAC therapy. Hydrocephalus requiring shunt placement developed in 2 patients during VAC therapy. The VAC dressings applied to a tissue matrix or other barrier over brain tissue in extensive cranial wounds are safe and well tolerated, providing a functional barrier and preventing infection.

Severity of the Harlequin deformity seen in unicoronal synostosis may be augmented when frontoparietal suture synostosis has an associated fusion of the frontosphenoidal suture or in cases of isolated frontosphenoidal synostosis. The purpose of the current study is to characterize various suture fusion patterns along the coronal ring using a modified orbital index (MOI), orbital angle (OA), and endocranial base (EB) angle. This study is a retrospective single institution cohort study. Charts were reviewed over the past 12 years; patients with isolated UCS were included. MOI, OA, and EB were used to identify 3 groups of UCS patients. Twenty-one patients were identified for inclusion in skeletal dysmorphology analysis using MOI, OA, and EB measures. Frontoparietal synostosis patients were diagnosed at significantly younger ages than frontoparietal + frontosphenoidal patients (P = 0.0001). Ipsilateral MOI measures were more severe for frontoparietal patients compared with frontoparietal + frontosphenoidal patients (P = 0.0239). There was a trend for more severe ipsilateral OA measures in frontoparietal patients compared with frontoparietal + frontosphenoidal patients (P = 0.181). Modified orbital index, OA, and EB measurements are useful in the diagnosis of suture fusion patterns in UCS patients. Frontoparietal synostosis has more severe Harlequin deformity compared with frontoparietal + frontosphenoidal patients. Frontosphenoidal fusion coinciding with frontoparietal synostosis may blunt the severity of skeletal dysmorphology in UCS patients and be associated with a delayed diagnosis. Attention must be paid to assessing the frontosphenoidal suture to assure adequate surgical release.

In the interstitial matrix, collagen unfolding at physiologic temperatures is thought to facilitate interactions with enzymes and scaffold molecules during inflammation, tissue remodeling, and wound healing. We tested the hypothesis that it also plays a role in modulating flows and matrix hydration potential. After progressively unfolding dermal collagen in situ, we measured the hydration parameters by osmotic stress techniques and modeled them as linear functions of unfolded collagen, quantified by differential scanning calorimetry after timed heat treatment. Consistent with the hypothetical model, the thermodynamic and flow parameters obtained experimentally were related linearly to the unfolded collagen fraction. The increases in relative humidity and intensity of T2 maps were also consistent with interfacial energy contributions to the hydration potential and the hydrophobic character of the newly formed protein/water interfaces. As a plausible explanation, we propose that increased tension at interfaces formed during collagen unfolding generate local gradients in the matrix that accelerate water transfer in the dermis. This mechanism adds a convective component to interstitial transfer of biological fluids that, unlike diffusion, can speed the dispersion of water and large solutes within the matrix.

BACKGROUND Traumatic brain injuries remain a treatment enigma with devastating late results. As terminally differentiated tissue, the brain retains little capacity to regenerate, making early attempts to preserve brain cells after brain injury essential. OBJECTIVE To resuscitate damaged tissue by modulating edema, soluble cytokines, and metabolic products in the "halo" of damaged tissue around the area of central injury that progressively becomes compromised. By re-equilibrating the zone of injury milieu, it is postulated neurons in this area will survive and function. METHODS Mechanical tissue resuscitation used localized, controlled, subatmospheric pressure directly to the area of controlled cortical impact injury and was compared with untreated injured controls and with sham surgery in a rat model. Functional outcome, T2 magnetic resonance imaging hyperintense volume, magnetic resonance imaging spectroscopy metabolite measurement, tissue water content, injury cavity area, and cortical volume were compared. RESULTS There were significant differences between mechanical tissue resuscitation treated and untreated groups in levels of myoinositol, N-acetylaspartate, and creatine. Treated animals had significantly less tissue swelling and density than the untreated animals. Nonviable brain tissue areas were smaller in treated animals than in untreated animals. Treated animals performed better than untreated animals in functional tests. Histological analysis showed the remaining viable ipsilateral cerebral area was 58% greater for treated animals than for untreated animals, and the cavity for treated animals was 95% smaller than for untreated animals 1 month after injury. CONCLUSION Mechanical tissue resuscitation with controlled subatmospheric pressure can significantly modulate levels of excitatory amino acids and lactate in traumatic brain injury, decrease the water content and volume of injured brain, improve neuronal survival, and speed functional recovery.

Treatment of wounds using negative pressure wound therapy (NPWT) uses a nondegradable polyvinyl alcohol (PVA) foam in the application of negative pressures typically for 1–3 days. The purpose of this study was to construct and test biodegradable poly(e-caprolactone) (PCL) foam as a substitute for the PVA foam. Such a foam would be left within the wound until healing was achieved and form a biodegradable matrix into which tissue would grow. The use of such foam would obviate the need for any serial foam changes and a final foam removal, thus making patient care much easier and more economical. PCL foams were prepared by salt leaching and phase separation. Morphological and mechanical properties of the foams were characterized and compared to PVA foam. PCL and PVA foams were tested on the uncut surface of a pig liver maintained in a hydration chamber continuously replenished with saline under the conditions of negative pressure of 50 mm Hg for 72 h. The results demonstrated that PCL foam made from phase separation had the similar properties and function as the PVA foam. The results demonstrate that PCL foam is an appropriate substitute for currently used nondegradable PVA foam in NPWT applications. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.

Summary Background: The anesthetic risks and outcomes of the first 100 consecutive spring-assisted surgeries (SAS) for cranial expansion from a single institution are reported. The effect of number of procedures was also tested on hematocrit postoperative day 1 (POD1), anesthesia time, and surgery time of the first procedure. Methods: The records of 100 consecutive patients undergoing SAS were reviewed. Anesthesia management and related complications are presented. Time series linear regression analysis was performed on hematocrit POD1, anesthesia time, and surgery time of the first procedure. Results: The average age of the first insertion procedure was 4.4 and 9.0 months for the second removal procedure. Two patients were inadvertently extubated during positioning. Thirty-eight children had a decrease in blood pressure >20% from baseline. No child was admitted to the intensive care unit. No patient received any blood or blood product transfusion. Anesthesia time, surgery time, and hematocrit POD1 were correlated with procedure number or experience. Conclusions: Changes in anesthetic management resulted from changing the procedure. The reduction in volume resuscitation reduces the need for invasive monitoring. Facility and comfort with the surgical procedure increase with time and number of procedures performed. This experience further reduces blood loss and risk of transfusion.

The local pathogenesis of interstitial edema in burns is incompletely understood. This ex vivo study investigates the forces mediating water-transfer in and out of heat-denatured interstitial matrix. Experimentally, full-thickness dermal samples are heated progressively to disrupt glycosaminoglycans, kill cells, and denature collagen under conditions that prevent water loss/gain; subsequently, a battery of complementary techniques including among others, high-resolution magnetic resonance imaging, equilibrium vapor pressure and osmotic stress are used to compare water-potential parameters of nonheated and heated dermis. The hydration potential (HP) determined by osmotic stress is a measure of the total water-potential defined empirically as the pressure at which no net water influx/efflux into/from the dermis is detected. Results show that after heat denaturation, the HP, the intensity of T2-weighed magnetic resonance images, and the vapor pressure increase indicating higher water activity and necessarily, smaller contributions from colloidosmotic forces to fluid influx in burned relative to healthy dermis. Concomitant increases in HP and in water activity implicate local changes in interfacial and metabolic energy as the source of excess fluid-transfer potential. These ex vivo findings also show that these additional forces contributing to abnormal fluid-transfer in burned skin develop independently of inflammatory and systemic hydrodynamic responses.

Brown recluse spider (Loxosceles) bites cause lesions ranging from chronic necrotic ulcers to acute life-threatening sepsis. Based on our experience in treating acute and chronic wounds with negative pressure, we postulated that vacuum-assisted closure (VAC) would be valuable in this application. Chester pigs were procured and injected with purified brown recluse spider venom, 1 µl of venom in two anterior sites and 0·1 µl of venom in two posterior sites on their dorsum. For each concentration of venom, treatment consisted of either VAC or dry, non adherent dressings (control group). Each day, the wounds were inspected and measured. For wounds receiving 1·0 µl of venom, the control wounds decreased in surface area to 50% of initial size after 7 days and none had healed, whereas VAC-treated wounds were less than 50% after 48 hours and completely healed and reepithelialised after 8 days. Wounds with 0·1 µl of venom had 50% reduction after 5 days with no complete healing for control wounds, and the VAC wounds were 50% after 48 hours and all had closed and reepithelialised after 5 days. Our experimental study showed an accelerated healing time in the animals treated with the VAC as compared with controls.

Brown recluse spider (Loxosceles sp) bites continue to be a significant challenge to manage clinically. Sequelae from these lesions range from chronic necrotic ulcers that persist for months to an acute life-threatening course of sepsis. Negative pressure wound therapy using vacuum-assisted closure (VAC) has been described for use in both acute and chronic wounds. We present a novel application for the use of this therapy in a retrospective review of eight clinical cases treated with the VAC.

Scaphocephaly is an important but incompletely defined entity resulting from premature fusion of the sagittal suture. Our goal was to use the clarity afforded by three-dimensional computed tomographies (CTs) to discern what characteristics of this disease are most representative and singular. Furthermore, we sought to define a classification system wherein the dominant physical trait, as it results from varied sites of premature fusion, determines the type of scaphocephaly in a particular patient. All patients with CT-diagnosed isolated single-suture sagittal craniosynostosis seen by a single craniofacial surgeon and a single pediatric neurosurgeon over a 5-year period are included (N = 76). Patients were stratified into anterior, central, posterior, or complex subtypes dependent upon the presence of a single dominant characteristic as seen on CT scan. Anterior type features a transverse retrocoronal band; central type has a heaped sagittal ridge; posterior type has an especially prominent occiput; and complex type includes those patients in whom a single dominant feature is not present. Forty-eight patients fit into anterior, central, or posterior types. Thirteen percent (N = 7) lack a single dominant feature and are complex. Incidence and prevalence for each type in this population are the following: anterior, 13/24%; central, 16/29%; posterior, 19/35%; and complex, 7/13%. Heterogeneous points of initial fusion may be responsible for the differing representations. Clinical applications using this classification system are ongoing and may allow us to individualize surgical intervention to optimize clinical outcome.

Of the single-suture craniosynostoses, unicoronal synostosis (UCS) is widely acknowledged to represent the most varied and complex set of craniofacial deformities. This is attributed to the endocranial base being affected along with the coronal suture. This deformity may present with both coronal and frontosphenoidal synostosis and has been associated with elevated intracranial pressure; brain morphological abnormalities; vertical dystopia; ambylopia; malformations of the forehead, orbit, midface, and mandible; and behavioral, cognitive, and speech abnormalities. It is the variable structural presentation coupled with the long-term stability of the reconstruction that forms a complex reconstructive challenge. Our surgical technique concordantly addresses these associated structures beyond the isolated coronal suture. Although several surgical techniques have previously been described, there remains no consensus toward a preferred surgical approach to this dynamic and three-dimensional problem. We describe our technique of coronal and frontosphenoidal synostosis release as part of a frontotemporoparietal bone flap, release of the entire fronto-orbital rim, and use of the unaffected skull to reconstruct the affected half of the skull. The purpose of our study was to describe our surgical approach to UCS. It has been our experience that optimal correction of UCS must address the associated anomalies beyond the affected coronal suture and must be stable over time.

Proboscis lateralis is a rare spontaneous congenital anomaly that results from a failure of normal embryological nasal development. The ensuing deformity consists of imbrication of the nasal soft tissues into a tubelike proboscis and can be associated with ipsilateral heminasal aplasia, choanal atresia, and multiple other abnormalities. A case report of a patient with proboscis lateralis is presented, with a 27-year follow-up detailing the complexities of long-term surgical management. After 15 major surgical interventions, there is relatively normal facial symmetry, but abnormalities remain with the underlying craniofacial skeleton and nasopharyngeal airway. Proboscis lateralis is not an isolated soft tissue abnormality but is a craniofacial defect that requires a long-term multidisciplinary approach to the surgical timing and treatment with lifelong follow-up.

Vascular malformations are described in 25 members of one affected family. Most of these lesions were cavernous hemangiomas, but arteriovenous malformations and capillary hemangiomas were also microscopically observed in some specimens. The five generation pedigree suggests the vascular malformations are genetically determined on the basis of a dominant inherited trait.

Craniofacial surgery continues to be progressive in its approach to maximize function and aesthetic appearance while minimizing risks and complications. Dynamic springs are one way to minimize invasiveness while achieving favorable results. The purpose of this study was to show the safety and efficacy of dynamic springs with resorbable foot plates for treatment of metopic suture abnormalities in a swine model. The study population consisted of twelve 20 kg Chester swine. The swine were divided into two treatment groups: four in the sham surgery group and eight in the stainless steel spring group. Postoperative analysis consisted of evaluation of the skull growth over time and integrity of the foot plates and underlying dura. The swine, killed at 8 weeks, were examined for spring location in the foot plates, ease of removal of the spring, and postmortem histologic analysis of the bone growth. No morbidity or mortality occurred in the immediate perioperative period secondary to the surgery. Postmortem histologic analysis revealed no infections or complications related to the surgery. Statistical analysis using a mixed linear model with an unstructured variance-covariance matrix was fit. In conclusion, this study confirms the efficacy and safety of the spring-mediated cranioplasty at the metopic suture with use of resorbable foot plates in a swine model.

Myocardial ischemia-reperfusion injury is known to trigger an inflammatory response involving edema, apoptosis, and neutrophil activation/accumulation. Recently, mechanical tissue resuscitation (MTR) was described as a potent cardioprotective strategy for reduction of myocardial ischemia-reperfusion injury. Here, we further describe the protective actions of MTR and begin to define its therapeutic window.A left ventricular, free-wall ischemic area was created in anesthetized swine for 85 minutes and then reperfused for three hours. Animals were randomized to two groups: (1) untreated controls (Control) and (2) application of MTR that was delayed 90 minutes after the initiation of reperfusion (D90). Hemodynamics and regional myocardial blood flow were assessed at multiple time points. Infarct size and neutrophil accumulation were assessed following the reperfusion period. In separate cohorts, the effect of MTR on myocardial interstitial water (MRI imaging) and blood flow was examined.Both groups had similar areas at risk (AAR), hemodynamics, and arterial blood gas values. MTR, even when delayed 90 minutes into reperfusion (D90, 29.2 ± 5.0% of AAR), reduced infarct size significantly compared to Controls (51.9 ± 2.7%, p = 0.006). This protection was associated with a 33% decrease in neutrophil accumulation (p = 0.047). Improvements in blood flow and interstitial water were also observed. Moreover, we demonstrated that the therapeutic window for MTR lasts for at least 90 minutes following reperfusion.This study confirms our previous observations that MTR is an effective therapeutic approach to reducing reperfusion injury with a clinically useful treatment window.

Le Fort III osteotomy is commonly used in the surgical correction of midface hypoplasia, specifically in patients with syndromic craniosynostosis. These osteotomies can be associated with significant complications, which are often the result of incomplete or inaccurate osteotomies. Brainlab, a technology first developed for neurosurgery, has been applied to numerous surgical subspecialties. The aim of this study was to report our initial experience using the Brainlab VectorVision2 and Brainlab Curve (Brainlab, Westchester, IL) as an intraoperative guidance system for osteotomy placement during Le Fort III advancement. Three pediatric patients with syndromic craniosynostosis and midface hypoplasia scheduled to undergo Le Fort III advancement were scanned preoperatively with 0.6-mm computed tomography cuts, which were then uploaded to the Brainlab system. All surgeries commenced with rigid fixation of the Brainlab registration device to the patient's skull. The navigation system was used intraoperatively to accurately determine osteotomy sites and trajectories. External distractors were placed without complication. Mean length of surgery was 331 minutes, and mean estimated blood loss was 500 mL. No transfusion was required with a mean postoperative hemoglobin of 8.3 g/dL. The application of Brainlab technology to Le Fort III advancement proved useful in establishing precise osteotomy lines and trajectories. Looking forward, this technology could be applied to a minimal dissection technique in order to avoid extensive blood loss. Further study would be needed to determine possible benefits such as reduced complications or operative time when using an intraoperative navigation system for image-guided osteotomy placement during Le Fort III advancement.

Treatment of wounds has been the cornerstone of plastic surgery since its inception. Vacuum-assisted closure provides a new paradigm that can be used in concert with a wide variety of standard existing plastic surgery techniques. It was originally developed as an alternative treatment for debilitated patients with chronic wounds. It has rapidly evolved into a widely accepted treatment of chronic and acute wounds, contaminated wounds, burns, envenomations, infiltrations, and wound complications from failed operations. The ease of technique and a high rate of success have encouraged its adaptation by thoracic, general, trauma, burn, orthopedic, urologic, as well as plastic surgeons. This article discusses multidisciplinary advances in the use of the vacuum-assisted closure technique over the past 10 years and its status as of 2006. Creative surgeons continue to regularly adapt the system to difficult problems. This technique in trained surgical hands greatly enhances the scope and safety of wound treatment.

UNLABELLED Transfusion-related acute lung injury (TRALI) is a potentially life-threatening, systemic, immune-mediated reaction to transfused blood product. The symptoms may be masked under general anesthesia. In this case report, we describe an infant who developed TRALI under general anesthesia for craniofacial surgery. The difficulty with diagnosis, the pathophysiology, and the need for understanding and recognition to reduce morbidity and mortality are discussed. IMPLICATIONS Transfusion-related acute lung injury (TRALI) is a life-threatening problem that can occur during blood product transfusion in patients of any age. Understanding the pathophysiology may help make an earlier diagnosis to reduce more serious adverse outcomes.

The gold standard for closing small cranial defects is autogenous bone: iliac crest, rib, or split calvarial grafts. Autogenous grafts result in donor site morbidity, increased operative time, blood loss, and additional cost, and they are limited in quantity. Hydroxyapatite cements are alternative bone substitutes that eliminate these restrictions. Although the use of hydroxyapatite is well accepted in completely developed crania, its use in the growing pediatric skull is limited. The purpose of the current study was to address the safety and long-term efficacy of this bone substitute for the repair of craniofacial bone defects in the growing pediatric skull. Safety is measured dually by resistance of bone substitute to infection and its tolerability by lack of a foreign body reaction. Efficacy is evaluated as structural skull integrity, volume stability with time, aesthetic quality, and most importantly, the ability to integrate adequately into a growing cranium without subsequent deformity or complications. This is a retrospective review of all pediatric patients at the authors' institution who underwent reconstruction of cranial defects using hydroxyapatite cement between May 1997 and March 2001. Eight patients who underwent 11 operations between the ages of 25 and 100 months (mean, 55 months) were followed up between 23 and 72 months (mean, 38 months). No mortalities or significant morbidities were encountered in the study population. It has been the authors' experience that hydroxyapatite cement is both biocompatible and resistant to infection when used in sites not contiguous with sinus mucosa; and that it is a good alternative to autogenous bone in pediatric craniofacial reconstruction.

Deformational plagiocephaly, cranial asymmetry secondary to positioning, continues to be a leading cause of head shape abnormalities in infants. Treatment recommendations include nonintervention, positioning therapies, and helmet therapy. Although most agree that surgical intervention is rarely indicated, the ideal therapy is not agreed on. Some even debate the necessity of treatment, especially third-party payers. The purpose of this prospective study is to use an objective outcome analysis tool, computerized tomography, to assess the efficacy of a soft shell helmet therapy. Sixty-nine children with a diagnosis of deformational plagiocephaly were enrolled in this study to assess the success of a soft shell helmet for the correction of cranial asymmetry. Computed tomography scanning was done before therapy and 6 months after the initiation of therapy. Three-dimensional reconstructions of these scans were reformatted into a standardized orientation by utilizing the nasion (radix), frontozygomatic suture lines, and posterior aspect of the foramen magnum. Intracranial volumes were calculated on a quadrant basis, and asymmetry was evaluated with regard to the hemispheres (left versus right) and the posterior quadrants. Thirty-four children (27 boys and 7 girls) completed the study protocol. The side involved was the right in 62% of cases and the left in 38%. Mean age at the initial scan was 6.3 months, and mean age at the follow-up scan was 14 months. Mean duration of helmet therapy was 7 months. Compliance with therapy was average to above average in 88% of the children and poor in 12%. There was a 36% to 54% improvement in asymmetry in the compliant patients over the 6-month study period. Soft shell helmet therapy is an effective technique to decrease cranial asymmetry based on objective outcome measurements. Additionally, it is cost-effective, with the total cost of therapy for the helmet and office visits ranging from 600 dollars to 700 dollars. This therapy compares favorably with other more expensive and time-consuming therapies that have been reported in the literature.

In an effort to accelerate vascularization and simplify the care of Integra (Ethicon, Inc., Somerville, N.J.), topical subatmospheric pressure was used for eight patients (age range, 2 to 60 years) with complex wounds. Bone was exposed in 62.5 percent of cases, joint in 50 percent, tendon in 37.5 percent, and bowel in 25 percent. The estimated Integra take rate was 96 percent. Split-thickness skin grafting was performed at 4 to 11 days (mean, 7.25 days), with a 93 percent take rate. No adverse side effects were observed with this technique. Application of subatmospheric pressure improved the take rate and time to vascularization of Integra, compared with previous published results, even with complicated wounds. This technique may be a practical alternative to flap closure.

Methods for surgical correction of sagittal craniosynostosis have progressed. The hypothesis is that advances in surgical interventions for craniosynostosis affect perioperative anesthetic care. We reviewed the records of eight children who underwent cranial vault reconstruction (CVR) and nine who underwent spring-mediated cranial expansion (SME) for sagittal craniosynostosis. We compared the data from the CVR procedure to data from the combined procedures for SME (insertion and removal of springs). Anesthesia times were similar between the CVR (4 h 24 min) and the combined SME (4 h 27 min) groups, whereas surgical times were different between the CVR (3 h 25 min) and combined SME groups (2 h 21 min) (P = 0.002). Length of stay was 4.1 days for the CVR group (confidence interval [CI], 3.8-4.4 days) versus 3.1 days (CI, 2.9-3.4 days) in the combined SME group (P = 0.0001). Blood loss was significantly less in the combined SME group at 48 mL (CI, 29 - 83 mL) compared with the CVR group at 291 mL (CI, 230-352 mL). All eight patients in the CVR group received blood with a mean of 1.4 U (range, 1-2 U). No SME patient received any blood products. The reduction in blood loss with this new surgical treatment is significant for the patient in reducing blood transfusion and for the anesthesiologist in reducing concerns of volume resuscitation.

Since the beginning of craniofacial surgery, there has been an ongoing search for surgical techniques to enhance outcome while, at the same time, decreasing the invasiveness of the surgical treatment of craniofacial deformities. The purpose of this study was to test a recently reported minimally invasive treatment modality, the dynamic spring, in a rabbit calvarial model for efficacy and safety. Specifically, the results of spring cranioplasty on skull growth, the underlying brain, and adjacent bone were to be assessed. The study population consisted of 36 7-week-old New Zealand white rabbits. The rabbits were divided into four treatment groups (9 rabbits each): control, sham surgery, stainless steel springs, and memory metal springs. Postoperative analysis included weekly radiographs to evaluate movement of amalgam markers placed at standardized locations. Additionally, 16 rabbits (4 from each group) were killed at 14 days after surgery, and postmortem histological analysis was done. The remaining rabbits were followed until they were adults and were then killed and similarly analyzed. No morbidity or mortality occurred in the immediate perioperative period secondary to the surgery. Postmortem histological analysis of all study animals revealed no intracranial, subcutaneous, or skin infections and no technical complications related to the surgery. Statistical analysis using ANOVA and pair-wise comparisons between treatment groups revealed a statistically significant difference (P < 0.05) between the marker movement in the spring groups versus the sham and control groups. There were no significant differences between the sham and control groups or between the two spring groups. In conclusion, this study confirms the efficacy and safety of the dynamic spring in a rabbit model.

Crouzon syndrome is an autosomal dominant disorder resulting in facial dysmorphism and craniosynostosis involving multiple cranial sutures. A common but often unrecognized early complication associated with craniosynostosis is a finding of increased intracranial pressure (ICP). This increase in ICP can lead to optic atrophy, neuronal damage, and mental deficits. The case of a 21-month-old girl with Crouzon syndrome is described. Although the child was clinically asymptomatic, a routine ophthalmic exam revealed papilledema and subsequently increased intracranial pressure and craniosynostosis were found. Cranial expansion and bicanthal advancement were performed to relieve the increased pressure. In cases such as these, long-term follow-up is essential because of the progressive nature of the disorder as well as the possibility of a recurrence of elevated intracranial pressure and a need for secondary decompressive surgery.

Neonates rely on the nasal airway for their source of air; thus, any compromise in the ability to inhale will dramatically alter their ability to breathe. Congenital nasal pyriform aperture stenosis is a rare yet serious form of airway obstruction due to overgrowth of the maxilla at the medial nasal process. Infants typically present with difficulty feeding and obvious difficulty breathing. Radiologic imaging aids in confirming the diagnosis and assists in operative planning to open the medial nasal process to reduce airway resistance. Further corrective surgery is often needed and is planned commensurate with facial growth. We present a novel case of a child diagnosed with congenital nasal pyriform aperture stenosis who has performed extraordinarily well intellectually and has achieved an excellent cosmetic and physiological reconstruction of the nose and airway.

The use of subatmospheric pressure to promote wound healing has increased in popularity during the last several years. The original studies on granulation tissue formation used a 125-mmHg vacuum. The use of alternative sources of subatmospheric pressure has led to many questions regarding efficacy or risk. In this report a swine model is used to quantify and compare the effects of low vacuum suction (25 mmHg) and high vacuum suction (500 mmHg) produced by various vacuum pumps and wall suction systems with the standard 125-mmHg vacuum. Additionally, the effects of an unregulated air leak in the sealing system were examined. All four wound treatments were examined on each of 4 pigs. Wounds were treated until one of the wounds had granulated to a level flush with the surrounding tissue. Wounds treated with the standard 125-mmHg vacuum had filled with granulation tissue by day 8. At this time wounds treated with 25 mmHg had filled 21.2% with new granulation tissue, and wounds treated with 500 mmHg had filled 5.9% with new tissue. Wounds treated with 125 mmHg with a hole in the sealing drape had increased in size 197% because of the debridement of necrotic tissue. In conclusion, wounds treated with a 125-mmHg vacuum exhibited a significant (p < 0.0001) increase in the rate of granulation tissue formation compared with treatment at 25 mmHg or 500 mmHg. The presence of an unregulated air leak in the sealing drape results in significant progression (p < 0.0001) of the wound secondary to dehydration and progressive necrosis.

Twenty-seven consecutive pediatric patients presenting to the orthopaedic surgery or plastic surgery services were reviewed after completion of wound care with the Vacuum Assisted Closure (V.A.C.) system. Each patient presented with complex soft tissue wounds requiring coverage procedures. Patients with acute wounds and wounds present after nonsuccessful attempts at surgical closure (dehisced incisions and failed flaps) were treated. All soft tissue defects healed without extensive coverage procedures using the V.A.C. system. In the majority of patients, use of the V.A.C. system produced a profuse bed of granulation tissue over all exposed bone, tendon, joint, and/or hardware, which could be covered with split thickness skin graft. Other patients were treated successfully with delayed primary closure, local flap advancement (one patient underwent a pedicled cross-leg flap), or by secondary intention. Use of the V.A.C. device is valuable in increasing the rate of granulation tissue formation and healing of extensive soft tissue injuries in pediatric patients. This vacuum system aids in the debridement of necrotic tissue and local soluble inflammatory mediators that may inhibit the proliferation of granulation tissue. These improvements in the local wound environment seem to accelerate wound healing compared with traditional methods. Before the development of the V.A.C. system, a minimum of nine patients within this group would have required free tissue transfer to obtain adequate coverage. The V.A.C. device seems to permit earlier coverage with local tissue or split-thickness skin grafting techniques, thereby decreasing the need for extensive microvascular tissue transfers in pediatric patients.

Fasciotomy wounds can be a major contributor to length of stay for patients as well as a difficult reconstructive challenge. Once the compartment pressure has been relieved and stabilized, the wound should be closed as quickly and early as possible to avoid later complications. Skin grafting can lead to morbidity and scarring at both the donor and fasciotomy site. Primary closure results in a more functional and esthetic outcome with less morbidity for the patient, but can often be difficult to achieve secondary to edema, skin retraction, and skin edge necrosis. Our objective was to examine fasciotomy wound outcomes, including time to definitive closure, comparing traditional wet-to-dry dressings, and the vacuum-assisted closure (VAC) device. This retrospective chart review included a consecutive series of patients over a 10-year period. This series included 458 patients who underwent 804 fasciotomies. Of these fasciotomy wounds, 438 received exclusively VAC. dressings, 270 received only normal saline wet-to-dry dressings, and 96 were treated with a combination of both. Of the sample, 408 patients were treated with exclusively VAC therapy or wet-to-dry dressings and 50 patients were treated with a combination of both. In comparing all wounds, there was a statistically significant higher rate of primary closure using the VAC versus traditional wet-to-dry dressings (P < 0.05 for lower extremities and P < 0.03 for upper extremities). The time to primary closure of wounds was shorter in the VAC. group in comparison with the non-VAC group. This study has shown that the use of the VAC for fasciotomy wound closure results in a higher rate of primary closure versus traditional wet-to-dry dressings. In addition, the time to primary closure of wounds or time to skin grafting is shorter when the VAC was employed. The VAC used in the described settings decreases hospitalization time, allows for earlier rehabilitation, and ultimately leads to increased patient satisfaction.

Application of subatmospheric pressure to sites injected with doxorubicin prevented ulcer formation in treated sites (0 ulcers/16 sites) compared to control wounds (10 ulcers/16 sites) in a pig model. Background and Objectives Extravasation of doxorubicin hydrochloride (Adriamycin) frequently causes chronic ulcers, which usually progress and expose underlying structures such as tendons and bone. The exact mechanism of action that causes cell death and the chronic ulcers is unknown. Methods Eight sites were injected intradermally with doxorubicin on each of 4 pigs. Four sites on each animal served as untreated controls. The remaining four sites were exposed to 125 mm Hg subatmospheric pressure applied 1 h after injection. The sites were observed on a three times per week schedule. Sites that did not develop ulcers were re-injected up to a total of four injections. The animals were observed for 5 weeks. Results Ten of sixteen control sites developed ulcers. No subatmospheric pressure treated sites developed ulcers. The incidence of ulcer formation was significantly less for treated wounds compared to control wounds at P < 0.001 by Fisher's exact test. Conclusions This physical modality appears to successfully prevent ulcer formation after doxorubicin injection. J. Surg. Oncol. 1999;72:14–17. © 1999 Wiley-Liss, Inc.

Neuronal function depends on exquisite local regulation of a great variety of molecules and their interactions in the interstitial spaces. The timing and magnitude of interactions in the brain must depend on the hydraulic properties governing water and solute transfer across its matrix, but quantitative information on these properties has proved notoriously difficult to obtain, and uncertainties remain. Here, we adapt osmotic stress techniques to explore pressure-volume relationships and fluid-transfer parameters in brain tissue. Within 15-30 minutes of euthanasia, sets of brain tissue samples (12/brain, ∼1g each) were obtained from pigs (n =11) and immersed in baths adjusted to colloidosmotic pressures of 3-219 mmHg with polyethyleneglycol Mw 8000. The samples’ water influx/efflux was measured gravimetrically as a function of time, normalized by weight. Initial flow rates were calculated from the first derivative, at time = 0, of second-degree polynomials fitted to the progress curves. Rates were linearly proportional to the bath's pressure (r2 > 0.9). The hydraulic conductance calculated from the slope of fitted lines was 0.029 ± 0.008µl/min/g/mmHg, and the hydration potential, calculated from the pressure at initial rate = 0, was 64 ± 27 mmHg (means ± SD, n = 11).The hydraulic conductance, but not the hydration potential, decreased significantly when the bath temperature was reduced from 37 to 4°C. Compared to heart and skin, brain conductance value was higher. Further, the changes in hydraulic parameters with temperature were distinct for each organ. These results illustrate a simple, ex vivo, quantitative approach to probe specific water-transfer parameters and their changes in the brain. They indicate organ-dependent differences in flow regulation and the hydraulic properties of extracellular matrices.

Hallermann-Streiff syndrome is rare, with approximately 150 case reports in the world literature. The syndrome consists of proportionate nanism; hypotrichosis; atrophy and extreme thinness of the skin, particularly over the facial area; an unusual "bird-like" face with mandibular hypoplasia; a prominent thin, pointed nose; congenital cataracts; and severe dental abnormalities. This appears to be a sporadic mutation, and the inheritance pattern is unknown. Clinical management must focus on the more life-threatening and developmental issues early on, and aesthetic deformities can be addressed after the adolescent growth period is complete. Surgical correction of cataracts should be undertaken early in life to preserve vision. Airway issues need to be addressed early. Other reconstructive procedures, including rhinoplasty, facial augmentation, and mandibular surgery, have been successful and can be performed later in life. We report on our clinical findings in 15 patients with this condition, our attempts at reconstruction, and complications we have encountered in treating this patient population. Five of our patients had produced normal chromosome studies, and none have had similarly affected siblings. Four have had normal, unaffected children. Most of our patients have undergone multiple reconstructive procedures and have done relatively well. Eleven of our patients, however, have encountered significant intermittent respiratory difficulty manifested as early feeding difficulty, recurrent upper respiratory tract infection, sleep apnea, and respiratory arrest. Three patients required tracheostomy because of respiratory difficulty, and one child died of postoperative respiratory compromise. The management of these complicated and difficult patients is discussed.

Recurrent dislocation of the temporomandibu- lar joint is a relatively common problem for which many treatment alternatives have been described. When recur- rent dislocation fails to respond to conservative treatment or pain becomes a major problem, surgical intervention is warranted. Unfortunately, current treatments are unpre- dictable and are associated with problems such as foreign body reactions, degeneration, and recurrent pain. We de- scribe a new procedure, using a temporalis sling for the treatment of recurrent temporomandibular joint disloca- tion. The temporalis sling has been effective in preventing recurrent dislocation and has not disturbed the intricate articulation process involved in mouth opening. This al- ternative offers significant amelioration of abnormal joint function and pain.

Background Traumatic brain injuries (TBIs) continue to be a devastating problem with limited treatment options. Previous research applying controlled vacuum to TBI in a rat model resulted in smaller injuries and more rapid recovery. Objective To examine the effects of the application of a controlled vacuum (mechanical tissue resuscitation) to TBI in a large-animal model. The magnitude of vacuum, length of application, and length of delay between injury and the application of mechanical tissue resuscitation were investigated. Methods Localized, controlled cortical injuries were created in swine. Vacuums of -50 and -100 mm Hg were compared. Mechanical tissue resuscitation for 3 or 5 days was compared. Delays of 0, 3, or 6 hours between the creation of the TBI and the initiation of mechanical tissue resuscitation were examined. Analysis included histological assessments, computed tomographic perfusion, and magnetic resonance imaging (T2, proton magnetic spectra). Results A -100 mm Hg vacuum resulted in significantly smaller mean contused brain and hemorrhage volumes compared with -50 mm Hg and controls. Magnetic resonance spectra of treated animals returned to near baseline values. All 10 animals with 5-day mechanical tissue resuscitation treatment survived. Three of 6 animals treated for 3 days died after the discontinuation of treatment. A 3-hour delay resulted in similar results as immediate treatment. A 6-hour delay produced significant, but lesser responses. Conclusion Application of mechanical tissue resuscitation to TBI was efficacious in the large-animal model. Application of -100 mm Hg for 5 days resulted in significantly improved outcomes. Delays of up to 3 hours between injury and the initiation of treatment did not diminish the efficacy of the mechanical tissue resuscitation treatment.

Despite numerous advances, chronic and other difficult-to-manage wounds continue to be a treatment challenge. Presented is a new subatmospheric pressure technique: vacuum-assisted closure (The V.A.C.). The V.A.C. technique entails placing an open-cell foam dressing into the wound cavity and applying a controlled subatmospheric pressure (125 mmHg below ambient pressure). Three hundred wounds were treated: 175 chronic wounds, 94 subacute wounds, and 31 acute wounds. Two hundred ninety-six wounds responded favorably to subatmospheric pressure treatment, with an increased rate of granulation tissue formation. Wounds were treated until completely closed, were covered with a split-thickness skin graft, or a flap was rotated into the health, granulating would bed. The technique removes chronic edema, leading to increased localized blood flow, and the applied forces result in the enhanced formation of granulation tissue. Vacuum-assisted closure is an extremely efficacious modality for treating chronic and difficult wounds.

A series of basic animal studies using a new subatmospheric pressure technique (The V.A.C.) to expedite wound healing are presented. The technique entails placing an open-cell foam into the wound, sealing the site with an adhesive drape, and applying subatmospheric pressure (125 mmHg below ambient) that is transmitted to the wound in a controlled manner. Utilizing a pig model, four studies were undertaken to determine the effect of subatmospheric pressure on laser Doppler-measured blood flow in the wound and adjacent tissue (N = 5), rate of granulation tissue formation (N = 10), clearance of bacteria from infected wounds (N = 5), and measurement of nutrient flow by random-pattern flap survival (N = 5). Blood flow levels increased fourfold when 125 mmHg subatmospheric pressure was applied. Significantly increased rates of granulation tissue formation (por = 0.05) occurred with both continuous (63.3 +/- 26.1%) and intermittent (103% +/- 35.3%) application. Tissue bacterial counts significantly decreased (por = 0.05) after 4 days of application. Random-pattern flap survival significantly increased (por = 0.05) by 21% compared to controls. We determined that the application of controlled subatmospheric pressure creates an environment that promotes would healing.