Poland-Möbius syndrome: a case report implicating a novel mutation of the PLXND1 gene and literature review.

BACKGROUND: Möbius (Moebius) and Poland's syndromes are two rare congenital syndromes characterized by non-progressive bilateral (and often asymmetric) dysfunction of the 6th and 7th cranial nerves and hypoplasia of the pectoral muscles associated with chest wall and upper limb anomalies respectively. Manifest simultaneously as Poland-Möbius (Poland-Moebius) syndrome, debate continues as to whether this is a distinct nosological entity or represents phenotypic variation as part of a spectrum of disorders of rhomboencephalic development. Etiological hypotheses implicate both genetic and environmental factors. The PLXND1 gene codes for a protein expressed in the fetal central nervous system and vascular endothelium and is thus involved in embryonic neurogenesis and vasculogenesis. It is located at chromosome region 3q21-q22, a locus of interest for Möbius syndrome. CASE PRESENTATION: We present the first report of a patient with Poland-Möbius syndrome and a mutation in the PLXND1 gene. A child with Poland-Möbius syndrome and a maternally inherited missense variant (NM_015103.2:ex14:c.2890G > Ap.V964M) in the PLXND1 gene is described. In order to contextualize these findings, the literature was examined to identify other confirmed cases of Poland-Möbius syndrome for which genetic data were available. Fourteen additional cases of Poland-Möbius syndrome with genetic studies are described in the literature. None implicated the PLXND1 gene which has previously been implicated in isolated Möbius syndrome. CONCLUSIONS: This report provides further evidence in support of a role for PLXND1 mutations in Möbius syndrome and reasserts the nosological link between Möbius and Poland's syndromes. LEVEL OF EVIDENCE: Level V, Descriptive Study.

Extremity Ischemia After Jellyfish Envenomation: A Case Report and Systematic Review of the Literature.

BACKGROUND: Extremity ischemia and necrosis after jellyfish envenomation can be mutilating and cause long-term functional deficits. The best way to manage these presentations is unknown. OBJECTIVE: The aim of this review was to establish an evidence-based consensus for the management of extremity ischemia after jellyfish envenomation. METHODS: A systematic review of cases of extremity ischemia and necrosis after envenomation by marine cnidarians was performed to clarify what is and what is not known about management and outcomes, to draw conclusions about how best to manage these rare presentations, and to establish an evidence-based algorithm. RESULTS: The ischemic sequelae of envenomation typically evolves over a few days. Close medical supervision is necessary to react promptly to the evolving clinical scenario. In the literature, 15 different pharmacologic classes have been used to manage these presentations. Only IV infusions of prostaglandin derivatives and intra-arterial thrombolytics have been found to improve the clinical picture and avoid the need for surgical fasciotomy and debridement in some cases. Anticoagulants, antiplatelet agents, steroids, antibiotics, and nitrates, which are among the most commonly prescribed pharmacologic agents, have not been observed to alter the clinical picture. CONCLUSIONS: Surgery for compartment syndrome and necrosis are common sequelae of extremity envenomation by marine cnidarians. Only prompt use of IV prostaglandins or intra-arterial thrombolytics can halt ischemic progression and avoid the need for surgery. An algorithm is proposed to guide management of these rare and mutilative presentations.

Seminal Studies in Facial Reanimation Surgery: Consensus and Controversies in the Top 50 Most Cited Articles.

ABSTRACT: Facial paralysis can impair one's ability to form facial expressions that are congruent with internal emotion. This hinders communication and the cognitive processing of emotional experience. Facial reanimation surgery, which aims to restore full facial expressivity is a relatively recent undertaking which is still evolving. Due in large part to published techniques, refinements, and clinical outcomes in the scientific literature, consensus on best practice is gradually emerging, whereas controversies still exist.Taking stock of how the discipline reached its current state can help delineate areas of agreement and debate, and more clearly reveal a path forward. To do this, the authors have analyzed the 50 seminal publications pertaining to facial reanimation surgery. In longstanding cases, the free gracilis transfer emerges as a clear muscle of choice but the nerve selection remains controversial with prevailing philosophies advocating cross facial nerve grafts (with or without the support of an ipsilateral motor donor) or an ipsilateral motor donor only, of which the hypoglossal and nerve to masseter predominate. The alternative orthodoxy has refined the approach popularized by Gillies in 1934 and does not require the deployment of microsurgical principles. Although this citation analysis does not tell the whole story, surgeons with an interest in facial reanimation will find that this is a good place to start.

Impact of Glabellar Paralysis on Facial Expression of Emotion.

BACKGROUND: Many prospective patients remain wary of the effects that glabellar muscle paralysis may have on their ability to normally communicate emotion with their face. OBJECTIVE: We undertook a direct empirical test of the effects of glabellar onabotulinum toxin type A injections on the ability to convey 6 universally recognized facial expressions of emotion. METHODS: Fifty-two female subjects ("expressors") were recorded on hidden camera while viewing video clips intended as a mood induction procedure that stimulates the 6 cardinal emotions (amusement, anger, disgust, fear, sadness, surprise). The subjects were then injected with 25 units of onabotulinum toxin A in the glabellar region. The subjects returned 1 month later and were again recorded while being spontaneously induced to express emotion. All video clips from both time periods from the 10 maximal expressors were extracted and shown to a group of 31 "perceivers" who rated the facial expressions for intensity (Likert 1-7) and identity of emotion (percent correct emotion identified). RESULTS: Glabellar paralysis significantly diminished mean perceived intensity of anger (50.4% relative reduction, P < 0.001) and surprise (20.6% relative reduction, P < 0.001). The mean intensity of disgust increased (39.0%, P < 0.001). Importantly, however, glabellar paralysis did not result in a significant change in observers' ability to discern provoked cardinal emotions. CONCLUSIONS: We believe these findings provide a measure of reassurance to patients and their providers that the use of onabotulinum toxin A to paralyze the glabellar musculature for aesthetic purposes may not pose a meaningful risk to the overall ability to express emotion during social interaction.

ERF-related craniosynostosis: The phenotypic and developmental profile of a new craniosynostosis syndrome.

Mutations in the ERF gene, coding for ETS2 repressor factor, a member of the ETS family of transcription factors cause a recently recognized syndromic form of craniosynostosis (CRS4) with facial dysmorphism, Chiari-1 malformation, speech and language delay, and learning difficulties and/or behavioral problems. The overall prevalence of ERF mutations in patients with syndromic craniosynostosis is around 2%, and 0.7% in clinically nonsyndromic craniosynostosis. Here, we present findings from 16 unrelated probands with ERF-related craniosynostosis, with additional data from 20 family members sharing the mutations. Most of the probands exhibited multisutural (including pan-) synostosis but a pattern involving the sagittal and lambdoid sutures (Mercedes-Benz pattern) predominated. Importantly the craniosynostosis was often postnatal in onset, insidious and progressive with subtle effects on head morphology resulting in a median age at presentation of 42 months among the probands and, in some instances, permanent visual impairment due to unsuspected raised intracranial pressure (ICP). Facial dysmorphism (exhibited by all of the probands and many of the affected relatives) took the form of orbital hypertelorism, mild exorbitism and malar hypoplasia resembling Crouzon syndrome but, importantly, a Class I occlusal relationship. Speech delay, poor gross and/or fine motor control, hyperactivity and poor concentration were common. Cranial vault surgery for raised ICP and/or Chiari-1 malformation was expected when multisutural synostosis was observed. Variable expressivity and nonpenetrance among genetically affected relatives was encountered. These observations form the most complete phenotypic and developmental profile of this recently identified craniosynostosis syndrome yet described and have important implications for surgical intervention and follow-up.

Pediatric Cervicofacial Actinomycosis: Lessons From a Craniofacial Unit.

Actinomycosis is a rare disease that remains difficult to diagnose and manage. Prompted by 2 recent cases the authors sought evidence-based conclusions about best practice. A systematic review was conducted using standard PRISMA methodology. The study was registered prospectively (PROSPERO: CRD42018115064). Thirty-three children from 23 series are described. The mean age was 8 years (range 3-17). Fifty-five percent were female. Twenty cases involved bone (usually mandible); 13 cases involved cervicofacial soft tissue. Poor dental hygiene and oral trauma were implicated. The median diagnostic delay was 12 weeks (range 1-156 weeks). The median duration of definitive antibiotic therapy was 17 weeks (range 1-130 weeks). Although diagnostic delay did not correlate with number of surgeries, bony involvement was associated with more procedures (P = 0.008, unpaired t test). All (6) cases with residual infection had bony involvement (P = 0.06, Fisher exact test). Neither diagnostic delay nor number of surgeries significantly influenced infection-free outcome which, instead, relies on aggressive surgical debridement and prolonged antibiotic therapy. Mandibular involvement exhibits a higher surgical burden and chronicity in around a third of cases. As dental caries are implicated in mandibular disease, preventative strategies must focus on improving pediatric oral hygiene.

Bell's palsy: a summary of current evidence and referral algorithm.

Spontaneous idiopathic facial nerve (Bell's) palsy leaves residual hemifacial weakness in 29% which is severe and disfiguring in over half of these cases. Acute medical management remains the best way to improve outcomes. Reconstructive surgery can improve long term disfigurement. However, acute and surgical options are time-dependent. As family practitioners see, on average, one case every 2 years, a summary of this condition based on common clinical questions may improve acute management and guide referral for those who need specialist input. We formulated a series of clinical questions likely to be of use to family practitioners on encountering this condition and sought evidence from the literature to answer them. The lifetime risk is 1 in 60, and is more common in pregnancy and diabetes mellitus. Patients often present with facial pain or paraesthesia, altered taste and intolerance to loud noise in addition to facial droop. It is probably caused by ischaemic compression of the facial nerve within the meatal segment of the facial canal probably as a result of viral inflammation. When given early, high dose corticosteroids can improve outcomes. Neither antiviral therapy nor other adjuvant therapies are supported by evidence. As the facial muscles remain viable re-innervation targets for up to 2 years, late referrals require more complex reconstructions. Early recognition, steroid therapy and early referral for facial reanimation (when the diagnosis is secure) are important features of good management when encountering these complex cases.

TNF-alpha promotes fracture repair by augmenting the recruitment and differentiation of muscle-derived stromal cells.

With an aging population, skeletal fractures are increasing in incidence, including the typical closed and the less common open fractures in normal bone, as well as fragility fractures in patients with osteoporosis. For the older age group, there is an urgent unmet need to induce predictable bone formation as well as improve implant fixation in situations such as hip joint replacement. Using a murine model of slow-healing fractures, we have previously shown that coverage of the fracture with muscle accelerated fracture healing and increased union strength. Here, we show that cells from muscle harvested after 3 d of exposure to an adjacent fracture differentiate into osteoblasts and form bone nodules in vitro. The osteogenic potential of these cells exceeds that of adipose and skin-derived stromal cells and is equivalent to bone marrow stromal cells. Supernatants from human fractured tibial bone fragments promote osteogenesis and migration of muscle-derived stromal cells (MDSC) in vitro. The main factor responsible for this is TNF-α, which promotes first MDSC migration, then osteogenic differentiation at low concentrations. However, TNF-α is inhibitory at high concentrations. In our murine model, addition of TNF-α at 1 ng/mL at the fracture site accelerated healing. These data indicate that manipulating the local inflammatory environment to recruit, then differentiate adjacent MDSC, may be a simple yet effective way to enhance bone formation and accelerate fracture repair. Our findings are based on a combination of human specimens and an in vivo murine model and may, therefore, translate to clinical care.

Beyond antisepsis: Examining the relevance of the works of Joseph Baron Lister to the contemporary surgeon-scientist.

As the father of antispesis, the legacy of Joseph Baron Lister is assured and his influence on the development of contemporary surgical practice is recognised in the context of his achievement of predictable, infection-free surgery. However, looking beyond Lister's finest achievement and examining this work in the context of his whole career as a surgeon-scientist reveals important lessons pertinent to aspiring peers in how, by replacing surgical dogma with observation, deductive reasoning and scientific verification, by pursuing good ideas in the face of resistance and by making research directly relevant and patient-focused, lasting changes can be accomplished. This short paper aims to put Lister's developments in antisepsis in the context of his whole career, to evaluate his legacy and to commend his approach to contemporary surgeon-scientists.

Bioelectrical Impedance Analysis Detects Body Fat Changes After Surgical Subcutaneous Fat Removal.

Background: The risk and metabolic effects of obesity are determined by the distribution of fat throughout the body. It has been proposed that the distribution of abdominal fat is more closely related to the metabolic risks of obesity. High prevalence of overweight and obesity has thereby contributed to an increased uptake of surgical subcutaneous fat removal (SSFR) procedures. The goal of this study was to determine whether bioelectrical impedance analysis (Tanita system) can be used to detect the removal of excess abdominal subcutaneous fat tissue during SSFR when studying the metabolic effects of such procedures. Methods: Study population comprised patients who received body contouring procedures at the Hamad General Hospital's plastic surgery department between November 2020 and December 2022. To evaluate the factors of interest, subjects were prospectively followed up at two time points: within 1 week before the surgery and within 1-2 weeks thereafter. The following factors were measured: body weight, body fat percentage, body fat mass, body mass index (BMI), fat-free mass, estimated muscle mass, total body water, visceral fat score, and basal metabolic rate. Results: In total, 22 patients were included in the study. The two visits' medians for height, weight, BMI, fat percent (fat%), fat mass, visceral fat rating, and Doi's weighted average glucose (dwAG) were compared. Only in the case of Tanita fat% and fat mass, were the preoperative and postoperative medians significantly different. Furthermore, there was no association between these Tanita measures and dwAG or homeostatic model assessment (HOMA; insulin resistance [IR]) changes (before and after surgery). Tanita measures overestimated fat loss, as seen by the mountain plot and Bland-Altman plot agreement methods. Conclusions: Our findings indicated that the only two Tanita measures exhibited meaningful early associations with the amount of tissue excised which were fat mass and fat% differences. Although dwAG and HOMA-IR are not impacted immediately postsurgery, a trend was seen that suggested improvements in those parameters, even though the changes are not clinically significant.

Metabolic changes after nonsurgical fat removal: A dose response meta-analysis.

BACKGROUND: Obesity-induced insulin resistance leads to the metabolic syndrome. Both bariatric surgery and surgical fat removal have been shown to improve metabolic health, but the metabolic benefits of nonsurgical fat removal remain uncertain. The aim of this paper is to establish whether nonsurgical fat removal exerts measurable, lasting metabolic benefits by way of changes to serum lipid profiles. METHODS: PubMed, Cochrane CENTRAL, Embase, and clinical trials registers were searched using the Polyglot Search Translator to find studies examining quantitative changes in metabolic markers after nonsurgical body contouring procedures. The MethodologicAl STandard for Epidemiological Research (MASTER) scale was adopted for the quality assessment of the included studies. The robust-error meta-regression (REMR) model was employed. RESULTS: Twenty-two studies and 676 participants were included. Peak body compositions measures manifest as a reduction of 2 units in body mass index (BMI), 1 kg of body weight (BW), 5 cm in waist circumference (WC) and 1.5 cm in abdominal fat thickness (FT), sustained up to 60 days postprocedure. Transient increases of 15 mg/dL in low-density lipoprotein (LDL), 10 mg/dl in triglycerides (TG), and 15 mg/dl in total cholesterol (TC) were observed at 2 weeks postprocedure. CONCLUSION: While nonsurgical fat removal exerts sustained effects on body anthropometrics, changes to serum lipid profiles were transient. There is no compelling evidence at present to support the conclusion that nonsurgical fat removal is metabolically beneficial.

Metabolic changes after surgical fat removal: A dose-response meta-analysis.

BACKGROUND: Bariatric surgery averts obesity-induced insulin resistance and the metabolic syndrome. By contrast, surgical fat removal is considered merely an esthetic endeavor. The aim of this article was to establish whether surgical fat removal, similar to bariatric surgery, exerts measurable, lasting metabolic benefits. METHODS: PubMed, Embase, and Scopus were searched using the Polyglot Search Translator to find studies examining quantitative expression of metabolic markers. Quality assessment was done using the MethodologicAl STandard for Epidemiological Research scale. The robust-error meta-regression model was employed for this synthesis. RESULTS: Twenty-two studies with 493 participants were included. Insulin sensitivity improved gradually with a maximum reduction in fasting insulin and homeostatic model assessment for insulin resistance of 17 pmol/L and 1 point, respectively, at postoperative day 180. Peak metabolic benefits manifest as a reduction of 2 units in body mass index, 3 kg of fat mass, 5 cm of waist circumference, 15 µg/L of serum leptin, 0.75 pg/ml of tumor necrosis factor-alpha, 0.25 mmol/L of total cholesterol, and 3.5 mmHg of systolic and diastolic blood pressure that were observed at day 50 but were followed by a return to preoperative levels by day 180. Serum high-density lipoproteins peaked at 50 days post-surgery before falling below the baseline. No significant changes were observed in lean body mass, serum adiponectin, resistin, interleukin-6, C-reactive protein, triglyceride, low-density lipoproteins, free fatty acids, and fasting blood glucose. CONCLUSION: Surgical fat removal exerts several metabolic benefits in the short term, but only improvements in insulin sensitivity last beyond 6 months.

Thin and superthin free flaps: An innovative approach to pediatric extremity reconstruction.

INTRODUCTION: Published standards for the management of open extremity fractures have improved limb salvage, fracture union, and deep infection rates, but the aesthetic and functional importance of our flap choices has been overlooked. Thin and superthin free flaps exhibit advantages over traditional free flaps in some situations but have seldom been reported in children. The aim of this paper is to present our experience of thin and superthin free flaps in pediatric extremity reconstruction. METHODS: Children (≤13 years) who underwent soft tissue reconstruction using a thin and superthin free flap following major extremity trauma are presented. RESULTS: Five patients (5 flaps) met the inclusion criteria. The median age was 9 (range 6-13). There were 3 Gustilo IIIB open fractures and 2 multiplanar degloving injuries. The median mangled extremity severity score (MESS) was 4 (range 2-6). The median time from injury to definitive soft tissue closure was 72 h (range 28-120 h). Four anterolateral thigh (ALT) flaps were raised as thin flaps, and 1 superficial circumflex iliac artery perforator (SCIP) was raised as a superthin flap. There was one re-exploration owing to venous congestion, and a second venous anastomosis was performed to enhance flap drainage. The same ALT flap exhibited necrosis at one margin, which was debrided and grafted before discharge. There were no other flap complications. No flap-related secondary surgeries were required. CONCLUSION: Thin and superthin free flaps are viable options in pediatric extremity reconstruction. They exhibit excellent aesthetic and functional contouring when a slender fasciocutaneous flap is needed, especially when body habitus renders traditional options unfavorable.

A recessive variant in SIM2 in a child with complex craniofacial anomalies and global developmental delay.

Rare deletions and duplications on the long arm of Chromosome 21 have previously been reported in many patients with craniofacial and developmental phenotypes. However, this Down Syndrome Critical Region (DSCR) contains multiple genes, making identifying a single causative gene difficult. Here, we report a case of a boy with bicoronal craniosynostosis, facial dysmorphism, developmental delay, and intellectual impairment who was found by whole genome sequencing to have a homozygous missense mutation in the Single-Minded Homolog 2 (SIM2) gene (c.461 A > G, p.Tyr154Cys) within the DSCR. SIM2 encodes an essential bHLH and PAS domain transcription factor expressed during fetal brain development and acts as a master regulator of neurogenesis. This variant is globally very rare, segregates in the family, and is predicted to be highly deleterious by in silico analysis, 3D molecular modeling of protein structure, and functional analysis of zebrafish models. Zebrafish expressing the human SIM2p.Y154C variant displayed a progressed microcephaly-like phenotype and head shape abnormalities. When combined with careful phenotyping of the patient vis-à-vis previously reported cases harboring structural variants in this critical 21q22 region, the data support a pathogenic role of SIM2 in this complex syndrome and demonstrates the utility of next-generation sequencing in prioritizing genes in contiguous deletions/duplications syndromes and diagnosing microarray-negative patients in the craniofacial clinic.

Photobiomodulation: A review of the molecular evidence for low level light therapy.

Light energy is harnessed for therapeutic use in a number of ways, most recently by way of photobiomodulation (PBM). This phenomenon is a cascade of physiological events induced by the nonthermal exposure of tissue to light at the near infrared end of the visible spectrum. Therapeutic PBM has become a highly commercialized interest, marketed for everything from facial rejuvenation to fat loss, and diode-based devices are popular in both the clinic setting and for use at home. The lack of regulatory standards makes it difficult to draw clear conclusions about efficacy and safety but it is crucial that we understand the theoretical basis for PBM, so that we can engage in an honest dialogue with our patients and design better clinical studies to put claims of efficacy to the test. This article presents a summary of the science of PBM and examines the differences between laser light, on which much of the preclinical evidence is based and light from diodes, which are typically used in a clinical setting.

Using Artificial Intelligence to Measure Facial Expression following Facial Reanimation Surgery.

Social interactions are largely dependent on the interpretation of information conveyed through facial expressions. Although facial reanimation seeks restoration of the facial expression of emotion, outcome measures have not addressed this directly. This study evaluates the use of a machine learning technology to directly measure facial expression before and after facial reanimation surgery. Fifteen study subjects with facial palsy were evaluated both before and after undergoing cross-facial nerve grafting and free gracilis muscle transfer. Eight healthy volunteers were assessed for control comparison. Video footage of subjects with their face in repose and with a posed, closed-lip smile was obtained. The video data were then analyzed using the Noldus FaceReader software application to measure the relative proportions of seven cardinal facial expressions detected within each clip. The facial expression recognition application detected a far greater happy signal in postoperative (42 percent) versus preoperative (13 percent) smile videos (p < 0.0001), compared to 53 percent in videos of control faces smiling. This increase in postoperative happy signal was achieved in exchange for a reduction in the sad signal (15 percent to 9 percent; p = 0.092) and the neutral signal (57 percent to 37 percent; p = 0.0012). For video clips of patients in repose, no significant difference in happy emotion was detected between preoperative (3.1 percent) and postoperative (1.4 percent) states (p = 0.5). This study provides the first proof of concept for the use of a machine learning software application to objectively quantify facial expression before and after surgical reanimation. CLINICAL QUESTION/LEVEL OF EVIDENCE:: Diagnostic, IV.

The Role of Bipartition Distraction in the Treatment of Apert Syndrome.

Apert syndrome is characterized by hypertelorism, a negative canthal axis, and central midfacial hypoplasia, resulting in a biconcave face. Bipartition distraction partially corrects these facial anomalies. This study investigates limitations of bipartition distraction using linear, angular, and geometric morphometric analysis. Preoperative and postoperative three-dimensional computed tomographic craniofacial constructs of 10 patients with Apert syndrome (aged 12 to 21 years) were annotated with 98 landmarks. Twelve age-, sex, and ethnicity-matched normal skulls provided control data. Principal component analysis was used to analyze shape characteristics within and between the groups and describe the changes occurring with surgery. Results were displayed graphically using difference color maps. Conventional point-based measurements documented midfacial width, height, and asymmetry. Apert three-dimensional constructs exhibited reduced upper midfacial height and greater extrinsic symmetric variation relative to controls. Facial bipartition partially corrected excessive midfacial width and interorbital distance but did not adequately correct deficient upper midfacial height. Excessive orbital diameter was unaltered by surgery. There was no demonstrable effect on intrinsic or extrinsic midfacial asymmetry. Principal component analysis demonstrated improved midfacial projection and correction of central biconcavity. Bipartition distraction corrects midfacial retrusion, exorbitism, and hypertelorism. It does not treat midfacial height disproportion or correct orbital shape. It leaves the face too wide at the zygomatic level and does not correct facial asymmetry. Although bipartition distraction is an improvement on the unmodified monobloc advancement, further refinements are needed to fully correct Apert dysmorphology.

Does negative-pressure wound therapy influence subjacent bacterial growth? A systematic review.

BACKGROUND: Negative-pressure wound therapy is a ubiquitous wound management resource. The influence of NPWT on the bacterial bioburden of the subjacent wound remains unclear. We sought to examine the evidence. DATASOURCES: MEDLINE, Embase, PubMed, the Cochrane Database of Systematic Reviews and the Cochrane Controlled Trials Register were searched for articles quantitatively evaluating bacterial load under NPWT. RESULTS: Twenty-four studies met the inclusion criteria including 4 randomised controlled trials, 8 clinical series and 12 experimental studies. Twenty studies evaluated conventional NPWT, while 4 evaluated infiltration-based NPWT. While 8 studies using conventional NPWT failed to demonstrate an observable effect on bacterial load, 7 studies reported that NPWT was inherently bacteriostatic and 5 others reported species selectivity with suppression of non-fermentative gram-negative bacilli (NFGNB), including Pseudomonas spp. Simultaneously, there was some evidence of enhanced proliferation of gram-positive cocci where the niche was cleared of NFGNB. Two of the 4 studies using infiltration-based NPWT also reported selectively impaired proliferation of Pseudomonas spp. CONCLUSION: The assumption that NPWT suppresses bacterial proliferation is oversimplified. There is evidence that NPWT exhibits species selectivity, suppressing the proliferation of NFGNB. However, this may depopulate the niche for exploitation by gram-positive cocci. This, in turn, has implications for the use of NPWT where highly virulent strains of gram-positive cocci have been isolated and the duration of NPWT therapy and frequency of dressing changes.