Comparison of negative pressure wound therapy against normal dressing after vascular surgeries for inguinal wounds: A systematic review and meta-analysis

Background

Negative Pressure Wound Therapy (NPWT) is a therapeutic technique of applying sub-atmospheric pressure to a wound to reduce inflammation, manage exudate, and promote the formation of granulation tissue. It aims to optimise the natural physiological processes of wound healing for more effective recovery, and NPWT has emerged as a promising alternative to traditional dressings.

Methods

The protocol followed in the study was prospectively registered. Appropriate search terms and Boolean operators were used to search electronic databases for relevant articles. Screening of articles was performed, and data extraction was done. The effect measure was chosen according to the nature of the variable, and the effect model was chosen as per heterogeneity. Forest plot was used to give visual feedback.

Results

This study included 11 randomized controlled trials (13 publications) with a total of 1310 patients (1497 inguinal wounds). The NPWT group had lesser odds of developing surgical site infection (OR: 0.40; 95 % CI: 0.29-0.54; n = 1491; I2 = 20 %; p-value ≤0.00001) and lesser odds of needing surgical wound revision (OR: 0.48; 95 % CI: 0.26-0.91; n = 856; I2 = 0 %; p-value = 0.02) as compared to the normal dressing group. No significant difference was observed in duration of hospital stay, cost of care, wound healing time, or other complications.

Conclusion

NPWT application in inguinal wounds significantly reduces the surgical site infection and the need for wound revision in patients who have undergone vascular surgery.

Pulsed negative pressure myofascial vacuum therapy and percutaneous electrolysis in the treatment of lateral epicondylalgia: A single-blind randomized controlled trial

BACKGROUND

Lateral Epicondylalgia (LE) represents one of the most common injuries of the upper limb. It is necessary to find effective treatments that reduce pain and increase functionality.

PURPOSE

To determine the effects of an integrated intervention of Pulsed Negative Pressure Myofascial Vacuum Therapy (VT), Percutaneous Electrolysis (PE) and eccentric exercise (EE) in the treatment of LE compared versus Manual Therapy soft tissue mobilization (MT) and Ultrasound therapy (US) and EE.

STUDY DESIGN

Single-blind randomized controlled trial.

METHODS

Forty participants, with unilateral LE, were randomly divided into two groups: VT + PE + EE group (n = 20) and MT + US + EE group (n = 20). The VT + PE + EE group received one weekly session for four weeks and a regimen of EE daily at-home, and the MT + US + EE group received 10 sessions over a period of two weeks and a regimen of EE daily at-home. Numerical pain rating scale (NPRS), range of motion (ROM) pressure pain threshold (PPT) and function (PRTEE questionnaire) were measured before treatment, at the end of treatment, and at one- and three-month follow-ups.

RESULTS

The statistically significant improvements were found post-treatment, favoring the VT + PE group in pain intensity (p < 0.001; ES = 0.408), PRTEE-S Pain (p = 0.001; ES = 0.377), PRTEE-S Specific function (p = 0.004; ES = 0.306) and PRTEE-S Total (p = 0.001; ES = 0.355). The VT + PE + EE treatment showed greater effectiveness than the MT + US + EE treatment at immediate post-treatment, as well as at the one-month and three-months follow-up.

CONCLUSIONS

VT and PE added to an EE program could be an effective treatment for pain, ROM, PPT, and function in patients with LE.

Comparison of the effectiveness of two adjustable negative pressure ureteral access sheaths combined with flex ureteroscopy for ≤ 2 cm renal stones

To compare the safety and effectiveness of the combination of intelligent intrarenal pressure control platforms (IPCP) and flexible ureteral access sheath (FUAS) combined with retrograde intrarenal surgery (RIRS) for the treatment of renal stones less than 2 cm. We retrospectively collected 383 patients with renal stones who underwent RIRS in our department from June 2022 to October 2023. Inclusion criteria: stone length or the sum of multiple stone lengths ≤ 2 cm. Finally, 99 cases were included and divided into an IPCP group (n = 40) and FUAS group (n = 59) based on surgical methods. The main endpoint was the stone-free rate (SFR) at third months after surgery, with no residual stones or stone fragments less than 2 mm defined as stone clearance. The secondary endpoints were surgical time and perioperative complications, including fever, sepsis, septic shock, and perirenal hematoma. There was no statistically significant difference in general information between the two groups, including age, gender, body mass index, comorbidities, stone side, stone location, stone length, urine bacterial culture, and hydronephrosis. The operation time for IPCP group and FUAS group was 56.83 ± 21.33 vs 55.47 ± 19.69 min (p = 0.747). The SFR of IPCP group and FUAS group on the first postoperative day was 75.00% vs 91.50% (p = 0.024). The SFR was 90.00% vs 94.90% in the third month (p = 0.349).In IPCP group, there were 11 cases with stones located in the lower renal calyces and 17 cases in FUAS group. The SFR of the two groups on the first day and third months after surgery were 45.50% vs 88.20% (p = 0.014) and 63.60% vs 94.10% (p = 0.040), respectively, with statistical differences. For kidney stones ≤ 2 cm, there was no difference in SFR and the incidence of infection-related complications between IPCP and FUAS combined with RIRS, both of which were superior to T-RIRS. For lower renal caliceal stones, FUAS has a higher SFR compared to IPCP.

Postoperative swelling after elbow surgery: influence of a negative pressure application in comparison to manual lymphatic drainage-a randomized controlled trial

PURPOSE

Postoperative soft tissue swelling is a significant factor influencing outcomes after elbow surgery. It can crucially affect important parameters such as postoperative mobilization, pain, and subsequently the range of motion (ROM) of the affected limb. Furthermore, lymphedema is considered a significant risk factor for numerous postoperative complications. Manual lymphatic drainage is nowadays part of the standardized post-treatment concept, basing on the concept of activating the lymphatic tissue to absorb stagnated fluid from the tissue into the lymphatic system. This prospective study aims to investigate the influence of technical device-assisted negative pressure therapy (NP) on early functional outcomes after elbow surgery. NP was therefore compared to manual lymphatic drainage (MLD). Is a technical device-based NP suitable for treatment of lymphedema after elbow surgery?

METHODS

A total of 50 consecutive patients undergoing elbow surgery were enrolled. The patients were randomized into 2 groups. 25 participants per group were either treated by conventional MLD or NP. The primary outcome parameter was defined as the circumference of the affected limb in cm postoperative up to seven days postoperatively. The secondary outcome parameter was a subjective perception of pain (measured via visual analogue scale, VAS). All parameters were measured on each day of postoperative inpatient care.

RESULTS AND CONCLUSION

NP showed an overall equivalent influence compared to MLD in reducing upper limb swelling after surgery. Moreover, the application of NP showed a significant decrease in overall pain perception compared to manual lymphatic drainage on days 2, 4 and 5 after surgery (p <  0.05).

CONCLUSION

Our findings show that NP could be a useful supplementary device in clinical routine treating postoperative swelling after elbow surgery. Its application is easy, effective and comfortable for the patient. Especially due to the shortage of healthcare workers and physical therapists, there is a need for supportive measures which NP could be.

Histologic features of bone regenerated by means of negative pressure in the context of odontogenic keratocyst

PURPOSE

The objective of the present research is to describe the histologic features of the bone regenerated by means of negative pressure (sugosteogenesis) in a group of patients diagnosed with odontogenic keratocyst (OKC) who underwent active decompression and distraction sugosteogenesis (ADDS) at our institution.

MATERIALS AND METHODS

The authors designed a retrospective case series study. The population included patients with a histologic diagnosis of odontogenic keratocyst in whom active decompression and distraction sugosteogenesis followed by enucleation was performed. All patients were seen and followed from July 2019 to January 2021. The investigation was approved by the Institutional Review Board, and it observed the Declaration of Helsinki on medical protocol. Variables of this study included age, gender, anatomic location (mandible or maxilla), and histologic characteristics of the bone regenerated by means of negative pressure. Histologic features were defined as being consistent or inconsistent with viable mature bone.

RESULTS

Bone biopsies of 6 patients were considered. In total, 83.33% of patients were males and 16.66% females. One hundred percent of the bone samples subjected to negative pressure showed features of viable mature bone.

CONCLUSIONS

In this study, the histological features of the bone subjected to negative pressure demonstrated the normal characteristics of the mature, normal bone.

Endoscopic vacuum therapy as a first-line treatment option for gastric leaks after bariatric surgery: evidence from 10 years of experience

BACKGROUND

Gastric (anastomotic or staple-line) leaks after bariatric surgery are rare but potentially life-threatening complications. Endoscopic vacuum therapy (EVT) has evolved as the most promising treatment strategy for leaks associated with upper gastrointestinal surgery.

OBJECTIVE

The aim of this study was to evaluate the efficiency of our gastric leak management protocol in all bariatric patients over a 10-year period. Special emphasis was placed on EVT treatment and its outcome as a primary treatment or as a secondary treatment when other approaches failed.

SETTING

This study was performed at a tertiary clinic and certified center of reference for bariatric surgery.

METHODS

In this retrospective single-center cohort study, clinical outcomes of all consecutive patients after bariatric surgery from 2012 to 2021 are reported, with special emphasis placed on gastric leak treatment. The primary endpoint was successful leak closure. Secondary endpoints were overall complications (Clavien-Dindo classification) and length of stay.

RESULTS

A total of 1046 patients underwent primary or revisional bariatric surgery, of whom 10 (1.0%) developed a postoperative gastric leak. Additionally, 7 patients were transferred for leak management after external bariatric surgery. Of these, 9 patients underwent primary and 8 patients underwent secondary EVT after futile surgical or endoscopic leak management. The efficacy of EVT was 100%, and there were no deaths. Complications did not differ between primary EVT and secondary treatment of leaks. Length of treatment was 17 days for primary EVT versus 61 days for secondary EVT (P = .015).

CONCLUSIONS

EVT for gastric leaks after bariatric surgery led to rapid source control with a 100% success rate both as primary and secondary treatment. Early detection and primary EVT shortened treatment time and length of stay. This study underlines the potential of EVT as a first-line treatment strategy for gastric leaks after bariatric surgery.

Negative pressure induces dedifferentiation of hepatocytes via RhoA/ROCK pathway

Biomechanical forces are known to regulate the biological behaviors of cells. Although negative pressure has been used for wound healing, it is still unknown about its role in regulating cell plasticity. We investigated whether negative pressure could induce the dedifferentiation of hepatocytes. Using a commercial device, we found that the exposure of primary human hepatocytes to -50 mmHg quickly induced the formation of stress fibers and obviously changed cell morphology in 72 h. Moreover, the exposure of hepatocytes to -50 mmHg significantly upregulated RhoA, ROCK1, and ROCK2 in 1-6 h, and dramatically enhanced the expression of marker molecules on "stemness", such as OCT4, SOX2, KLF4, MYC, NANOG, and CD133 in 6-72 h. However, all these changes in hepatocytes induced by -50 mmHg stimulation were almost abrogated by ROCK inhibitor Y27623. Our data suggest that an appropriate force of negative pressure stimulation can effectively induce the dedifferentiation of hepatocytes via RhoA/ROCK pathway activation.

Liquid-gas phase transition enables microbial electrolysis and H2-based membrane biofilm hybrid system to degrade organic pollution and achieve effective hydrogenotrophic denitrification of groundwater

Electron-donor Lacking was the limiting factor for the denitrification of oligotrophic groundwater and hydrogenotrophic denitrification provided an efficient approach without secondary pollution. In this study, a hybrid system with microbial electrolysis cell (MEC) assisted hydrogen-based membrane biofilm reactor (MBfR) was established for advanced groundwater denitrification. The liquid-gas phase transition prevented the potential pollution from organic wastes in MEC to groundwater, while the bubble-free diffusion of MBfR promoted hydrogen utilization efficiency. The negative-pressure extraction from MEC and the positive pressure for gas supply into MBfR increased the hydrogen proportion and current density of MEC, and improved the kinetic constant K of the denitrification reaction in MBfR. With actual groundwater, the MEC-MBfR hybrid system achieved a nitrate reduction of 97.8% with an effluent NO₃^--N of 2.2 ± 1.0 mg L^-1. The hydrogenotrophic denitrifiers of Thauera, Pannonibacter, and Azonexus, dominated the denitrification biofilm on the membrane and elastic filler in MBfR.

Establishment of Agrobacterium-mediated transformation system to Juglans sigillata Dode 'Qianhe-7'

An efficient genetic transformation system is of great significance for verifying gene function and improving plant breeding efficiency by gene engineering. In this study, a stable Agrobacterium mediated genetic transformation system of Juglans sigillata Dode 'Qianhe-7' was investigated using callus and negative pressure-assisted and ultrasonic-assisted transformation selection. The results showed that the axillary shoot leaves were suitable to induce callus and the callus proliferation rate could reach 516.27% when induction calli were cultured on DKW medium containing 0.5 mg L^-1 indole-3-butyric acid, 1.2 mg L^-1 2,4-dichlorophenoxyacetic acid and 0.5 mg L^-1 kinetin for 18 d. In addition, negative pressure infection was the optimal infection method with the lowest browning rate (0.00%), high GFP conversion rate (16.67%), and better growth status. To further prove the feasibility of this genetic transformation system, the flavonol synthetase (JsFLS₅) gene was successfully transformed into the into leaf-derived callus of 'Qianhe-7'. JsFLS₅ expression and the content of total flavonoids in transformed callus were improved significantly compared with the untransformed callus, which proved that we had an efficient and reliable genetic transformation system using leaf-derived callus of Juglans sigillata.

Removal of collagen three-dimensional scaffold bubbles utilizing a vacuum suction technique

The process of generating type I/II collagen scaffolds is fraught with bubble formation, which can interfere with the three-dimensional structure of the scaffold. Herein, we applied low-temperature vacuum freeze-drying to remove mixed air bubbles under negative pressure. Type I and II rubber sponges were acid-solubilized via acid lysis and enzymolysis. Thereafter, vacuum negative pressure was applied to remove bubbles, and the cover glass press method was applied to shape the type I/II original scaffold. Vacuum negative pressure was applied for a second time to remove any residual bubbles. Subsequent application of carbamide/N-hydroxysuccinimide cross-linked the scaffold. The traditional method was used as the control group. The structure and number of residual bubbles and pore sizes of the two scaffolds were compared. Based on the relationship between the pressure and the number of residual bubbles, a curve was created, and the time of ice formation was calculated. The bubble content of the experimental group was significantly lower than that of the control group (P < 0.05). The pore diameter of the type I/II collagen scaffold was higher in the experimental group than in the control group. The time of icing effect of type I and II collagen solution was 136.54 ± 5.26 and 144.40 ± 6.45 s, respectively. The experimental scaffold had a more regular structure with actively proliferating chondrocytes that possessed adherent pseudopodia. The findings indicated that the vacuum negative pressure method did not affect the physical or chemical properties of collagen, and these scaffolds exhibited good biocompatibility with chondrocytes.

Reducing donor-site complications in DIEP flap breast reconstruction with closed incisional negative pressure therapy: A cost-benefit analysis

INTRODUCTION

Deep inferior epigastric perforator (DIEP) flaps are considered the gold standard for autologous breast reconstruction but create large abdominal incisions that risk donor-site morbidity during harvest. Closed incision negative pressure therapy (ciNPT) is emerging as an effective alternative to standard postoperative dressings, but there is a paucity of data in DIEP flap donor sites.

METHODS

We conducted a retrospective case-control study investigating the use of ciNPT in DIEP flap donor sites at a single institution between March 2017 and September 2021. Patients who underwent microsurgical autologous breast reconstruction with DIEP flaps were included. Patients were divided into those with donor incision sites managed with ciNPT (n = 24) and those with conventional postoperative wound dressings (n = 20). We compared patient demographics, wound drainage volumes and postoperative outcomes between the two groups. A cost-benefit analysis was employed to compare the overall costs associated with each complication and differences in length of stay between the two groups.

RESULTS

There was no statistically significant difference in age, body mass index (BMI), comorbidity burden or smoking status between the two groups. Both groups had similar lengths of stay and wound drainage volumes with no readmissions or reoperations in either group. There was a statistically significant reduction in donor-site complications (p = 0.018), surgical site infections (p = 0.014) and seroma formation (p = 0.016) in those with ciNPT. Upon cost-benefit analysis, the ciNPT group had a mean reduction in cost-per-patient associated with postoperative complications of £420.77 (p = 0.031) and £446.47 (p = 0.049) when also accounting for postoperative length of stay CONCLUSION: ciNPT appears to be an effective alternative incision management system with the potential to improve complication rates and postoperative morbidity in DIEP flap donor sites. Our analysis demonstrates improved cost-benefit outweighing the increase in costs associated with ciNPT. We recommend a multicentre prospective trial with formal cost-utility analysis to strengthen these findings.

Cost Savings Associated with Vacuum-Assisted Closure in Trauma Patients Undergoing Posterior Spinal Fusion

OBJECTIVE

To investigate the implications of vacuum-assisted closure (VAC) versus standard wound dressings on postoperative posterior spinal fusion (PSF) wounds with respect to potential cost savings associated with reduced incidence of surgical site infections.

METHODS

This was a retrospective review of trauma patients who underwent open PSF under the care of a single surgeon at a Level I trauma center. Patients were postoperatively monitored for 90 days. Statistical analysis was performed with χ2 testing with the calculation of number needed to treat values.

RESULTS

Inclusion criteria were met by 208 patients who underwent open PSF. The χ2 test revealed a significant increase in incidence of surgical site infections (20% vs. 8%; P = 0.021) in the non-VAC group (n = 112) compared with the VAC group (n = 96). Cost-benefit analysis revealed that use of VAC in patients undergoing open PSF could enable a mean cost savings of $163,492 per 100 patients.

CONCLUSIONS

Use of VAC in patients undergoing open PSF was associated with a 2-fold decrease in incidence of surgical site infections and an infection-related cost savings of $163,492 per 100 patients. Further investigation is needed to ascertain additional benefits of VAC usage in patients undergoing open PSF.

Optimized mechanism for fast removal of infectious pathogen-laden aerosols in the negative-pressure unit

It has been frequently emphasized that highly contagious respiratory disease pathogens (such as SARS-CoV-2) are transmitted to the other hosts in the form of micro-sized aerosols (< 5 μm) in the air without physical contacts. Hospital environments such as negative-pressure unit are considered being consistently exposed to pathogens, so it is essential to quickly discharge them through the effective ventilation system. To achieve that, in the present study, we propose the optimized ventilation mechanism and design for the fastest removal of pathogen-laden aerosol using numerical simulations. We quantitatively evaluated the aerosol removal performance of various ventilation configurations (combinations of air exhaust and supply ducts), and found that the key mechanism is to form the coherent (preferentially upward) airflow structure to surround the respiratory flow containing the aerosol cluster. We believe that the present findings will play a critical role in developing the high-efficiency negative-pressure facility irrespective of its size and environments.

Novel strategy for rapid start-up and stable operation of anammox: Negative pressure coupled with the direct-current electric field

An application challenge of anaerobic ammonia oxidation (anammox) is the slow proliferation rate of anaerobic ammonium oxidation bacteria (AnAOB). This study adopted negative pressure coupled with the direct-current electric field (NP-DCEF) to evaluate system nitrogen removal performance. Results showed that the total nitrogen removal rate (TNRR) of the NP-DCEF system was stable at 88.6% after seven days. Compared with that of the ordinary operating system (45.4%), the relative abundance of Candidatus-kuenenia considerably increased from 51.9% to 57.6%. Under transient and long-term influent fluctuation, the NP-DCEF system showed high nitrogen removal performance. The specific activity of AnAOB (SAA) reached 11.0 mg N∙g Vss^-1 h^-1 under load fluctuation, and it was 8.7 mg N∙g Vss^-1 h^-1 under ordinary operational conditions. In addition, the specific activities of hydrazine dehydrogenase (HDH) and hydrazine synthetase (HZS) reached 32.66 and 92.95 U∙L^-1, which are considerably higher than those under the ordinary operating conditions (18.41 and 63.20 U∙L^-1). These results indicated that the novel operation strategy has specific feasibility and potential for the start-up and long-term operation of anammox.

Non-contact optical characterization of negative pressure in hydrogel voids and microchannels

Negative pressure in water under tension, as a thermodynamic non-equilibrium state, has facilitated the emergence of innovative technologies on microfluidics, desalination, and thermal management. However, the lack of a simple and accurate method to measure negative pressure hinders further in-depth understanding of the properties of water in such a state. In this work, we propose a non-contact optical method to quantify the negative pressure in micron-sized water voids of a hydrogel film based on the microscale mechanical deformation of the hydrogel itself. We tested three groups of hydrogel samples with different negative pressure inside, and the obtained results fit well with the theoretical prediction. Furthermore, we demonstrated that this method can characterize the distribution of negative pressure, and can thus provide the possibility of investigation of the flow behavior of water in negative pressure. These results prove this technique to be a promising approach to characterization of water under tension and for investigation of its properties under negative pressure.

[A mobile care unit dedicated to airbone infections]

A mobile care unit has been designed for infectious patients care in a humanitarian setting. Six individual compartments are grouped together in the main tent of 54 m² under negative air pressure. The principle of walking from clean to dirty is respected. The main indications are bacterial or viral infections with airborne transmission and an epidemic potential. The operating situations of this prototype, which has not yet been tested in the field, and its constraints in an underdeveloped country are presented.

Genesis of "negative pressure" during hanging drop; the answer is positive pressure

A drop of saline placed within the hub of an epidural needle is sucked in when the needle is advanced and penetrates through a polyurethane foam cube. This phenomenon might be explained by the release of compressed air inside of the needle into the air. The positive pressure inside of the needle may be generated by advancing of the needle. To prove this hypothesis, the pressure inside of the needle was measured during needle advancement, and it increased gradually and then dropped to zero suddenly when the needle fully penetrated the polyurethane foam block. We can speculate that the same phenomenon occurs during hanging-drop method of epidural anesthesia, and this may occur regardless of whether epidural subatmospheric pressure exists or not.

A new technique to detect communication sites for pleuroperitoneal communication

Pleuroperitoneal communication is one of the complications for continuous ambulatory peritoneal dialysis. Communication sites, such as defects or bleb-like lesions, are found in the diaphragm, but it is sometimes difficult to detect these sites. We combined the infrared thoracoscopy and negative pressure technique to detect communication sites. We think our new technique will become an alternative option for difficult and complex cases.

Evolution of endoscopic vacuum therapy for upper gastrointestinal leakage over a 10-year period: a quality improvement study

BACKGROUND

Endoscopic vacuum therapy (EVT) is an effective treatment option for leakage of the upper gastrointestinal (UGI) tract. The aim of this study was to evaluate the clinical impact of quality improvements in EVT management on patients' outcome.

METHODS

All patients treated by EVT at our center during 2012-2021 were divided into two consecutive and equal-sized cohorts (period 1 vs. period 2). Over time several quality improvement strategies were implemented including the earlier diagnosis and EVT treatment and technical optimization of endoscopy. The primary endpoint was defined as the composite score MTL30 (mortality, transfer, length-of-stay > 30 days). Secondary endpoints included EVT efficacy, complications, in-hospital mortality, length-of-stay (LOS) and nutrition status at discharge.

RESULTS

A total of 156 patients were analyzed. During the latter period the primary endpoint MTL30 decreased from 60.8 to 39.0% (P = .006). EVT efficacy increased from 80 to 91% (P = .049). Further, the need for additional procedures for leakage management decreased from 49.9 to 29.9% (P = .013) and reoperations became less frequent (38.0% vs.15.6%; P = .001). The duration of leakage therapy and LOS were shortened from 25 to 14 days (P = .003) and 38 days to 25 days (P = .006), respectively. Morbidity (as determined by the comprehensive complication index) decreased from 54.6 to 46.5 (P = .034). More patients could be discharged on oral nutrition (70.9% vs. 84.4%, P = .043).

CONCLUSIONS

Our experience confirms the efficacy of EVT for the successful management of UGI leakage. Our quality improvement analysis demonstrates significant changes in EVT management resulting in accelerated recovery, fewer complications and improved functional outcome.

The Influence of Low- and High-Negative-Pressure Liposuction and Different Harvesting Sites on the Viability and Yield of Adipocytes and Other Nucleated Cells

BACKGROUND

The volume effect of fat grafting is highly dependent on the presence of viable adipocytes and other nucleated cells within the lipoaspirate. We suspected that one of the crucial factors influencing cell viability is the negative pressure applied during the fat graft harvesting and the suitability of various harvest sites when compared to others. Despite much discussion, there is no consensus on the optimal negative pressure or the best site for harvesting so we designed an experiment to test this.

METHODS

Fat graft taken under low negative pressure (- 200 mmHg) or high negative pressure (- 700 mmHg) from the thigh or abdominal regions from 21 healthy human donors was evaluated. The principal variables studied were: a) total number and viability of nucleated cells, b) liposuction duration and c) blood admixture. Other variables studied were body mass index, the impact of age and enzymatic digestion.

RESULTS

The absolute number and viability of nucleated cells and the blood admixture did not differ significantly between lipoaspirates obtained under different vacuum conditions or from different regions. The time taken to acquire the same volume of lipoaspirate was significantly increased using low negative pressure. The time taken to collect cells in the thigh region significantly increased with increasing BMI but this correlation was not found when harvesting in the abdominal region. The BMI and age did not impact the results in any of the measured variables. The enzymatic digestion rate was independent of the negative pressure used to harvest.

CONCLUSION

Our results indicate that neither the negative pressure used nor the area chosen has any significant influence on the viability and yield of harvested cells. The time taken to obtain lipoaspirate using low pressure is significantly longer than when using high pressure. No significant difference was found in the value of blood admixture using different vacuum pressures, and no correlation exists between the body mass index and the cell viability or age of the patients and the time of liposuction.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine Ratings, please refer to Table of Contents or online Instructions to Authors www.springer.com/00266 .

Implementation and acceptance rates of a specially designed vacuometer for the vacuum bell treatment of pectus excavatum

BACKGROUND / PURPOSE

To report the implementation of a specially designed vacuometer for the ambulatory measurement of the exact negative pressure self-applied by the patient when using the vacuum bell for the treatment of pectus excavatum and to analyze patient satisfaction with the device, by conducting a survey.

METHODS

Between October 2018 and June 2020, all patients with pectus excavatum who received a vacuum bell at our Pectus Clinic were provided with a specially designed pectus vacuometer for their personal use. We described the vacuometer, the fundamentals of its development, and the utilization protocol. A survey was conducted evaluating comfort, clarity of instructions, usefulness, simplicity of connection, and likeability. The level of satisfaction was assessed using a Likert scale ranging from 1 (very negative experience) to 5 (very positive experience). The occurrence of skin lesions provoked by the application of the vacuum bell was registered.

RESULTS

From 72 submitted surveys, 54 patients answered. Patient demographics comprised 44 (81.5%) males and a mean age of 12.6 ± 6.0 years. The mean initial external pectus depth was 2.0 ± 0.7 cm and the mean duration of treatment was 13.2 ± 8.6 months. No skin lesions were detected while using the vacuum bell and the vacuometer. The mean general satisfaction score was 4.4 ± 0.7 and 83.3% of the respondents did not have any inconvenience with the vacuometer. A patient who considered himself cured was the only dropout during the study.

CONCLUSIONS

In this study, we described the feasibility and fundamentals of the application of a specifically designed vacuometer for ambulatory use as an adjunct to the treatment of pectus excavatum with a vacuum bell, and demonstrated a high satisfaction level with the device. In addition, the vacuometer might help avoid skin lesions secondary to the vacuum bell and foster adhesion to treatment.

TYPE OF STUDY

Treatment study.

LEVEL OF EVIDENCE

IV.

The Influence of High and Low Negative Pressure Liposuction and Various Harvesting Techniques on the Viability and Function of Harvested Cells-a Systematic Review of Animal and Human Studies

BACKGROUND

An understanding of fat grafting methodology, techniques and patient-related factors is crucial when considering fat grafting. Multiple factors can influence the success of a fat graft and consequently the outcome of the procedure. The aim of this systematic review is to elucidate the influence of negative pressure and various techniques of fat harvesting on the viability and function of cells, particularly adipocytes and adipose-derived stem cells.

METHODS

We conducted a literature search from 1975 to 2020 using the PubMed bibliography, ScienceDirect, SCOPUS and the Google Scholar databases which produced 168,628 articles on the first pass. After applying all the exclusion criteria by two independent reviewers, we were left with 21 articles (level IV of Oxford Centre for Evidence-Based Studies and Grade C of Grade Practice Recommendation from the American Society of Plastic Surgeons) on which this review is based.

RESULTS

From 11 studies focused on different negative pressures, no one found using high negative pressure advantageous. Summarising 13 studies focused on various harvesting techniques (excision, syringe, and pump-machine), most often equal results were reported, followed by excision being better than either syringe or liposuction.

CONCLUSION

From our systematic review, we can conclude that the low negative pressure seems to yield better results and that the excision seems to be the most sparing method for fat graft harvesting. However, we have to point out that this conclusion is based on a very limited number of statistically challengeable articles and we recommend well-conducted further research.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Management of post lobectomy subcutaneous emphysema; a case report with literature review

Introduction

Subcutaneous emphysema is an extremely rare complication after lobectomy. The current study aims to report a case of lung cancer developing extensive subcutaneous emphysema after lobectomy.

Case presentation

A 73-year-old man presented with dyspnea and cough for one month duration associated with wheeze and sputum. He was a chronic heavy smoker (100 pack/year). Work up revealed squamous cell carcinoma. Although he had poor pulmonary function tests, he underwent left upper lobectomy. On the fifth postoperative day, he was discharged from the hospital as there was no air leak and the lung remained expanded 15 hours after clamping of the thoracostomy tube. Two days later, the patient developed generalized subcutaneous emphysema. The patient was re-admitted to the hospital and a thoracostomy tube was inserted. The lung expanded upon insertion while the subcutaneous emphysema remained the same and even slightly increased over night. A 3 cm incision was made at the left infra-clavicular area and a negative pressure applied to it. The subcutaneous emphysema completely subsided a few hours after this intervention.

Discussion

Because of the benign course, the majority of cases of subcutaneous emphysema (mild to moderate) only need nonoperative management alongside treatment of the predisposing factors. These patients may need nothing other than bed rest, good analgesia, supplemental oxygen, and reassurance.

Conclusion

Subcutaneous emphysema after lobectomy prolongs hospital stay. It mainly occurs in cases with poor pulmonary function tests, steroid use, and those with extensive adhesion.

•

Subcutaneous emphysema is one of the complications following thoracic surgery.

•

Subcutaneous emphysema might be a benign and self-limiting condition.

•

It might be a serious condition that ends with respiratory failure and death.

•

In this report, a case of lung cancer developing subcutaneous emphysema after lobectomy discussed.

A Novel Negative Pressure, Face-Mounted Antechamber to Minimize Aerosolization of Particles During Endoscopic Skull Base Surgery

BACKGROUND

The COVID-19 pandemic has revealed deficiencies in the adequacy of personal protective equipment (PPE) for healthcare workers. Endoscopic endonasal skull base surgery is thought to be among the highest-risk aerosol-generating procedures for surgeons and operating room personnel.

OBJECTIVE

To validate the efficacy and clinical feasibility of a novel surgical device.

METHODS

A low-cost, modifiable, and easily producible negative pressure, face-mounted antechamber was developed utilizing 3D printing and silicone molding. Efficacy was evaluated using an optical particle sizer to quantify aerosols generated during both cadaver and intraoperative human use with high-speed drilling.

RESULTS

Particle counts in the cadaver showed that drilling led to a 2.49-fold increase in particles 0.3 to 5 μm (P = .001) and that the chamber was effective at reducing particles to levels not significantly different than baseline. In humans, drilling led to a 37-fold increase in particles 0.3 to 5 μm (P < .001), and the chamber was effective at reducing particles to a level not significantly different than baseline. Use of the antechamber in 6 complex cases did not interfere with the ability to perform surgery. Patients did not report any facial discomfort after surgery related to antechamber use.

CONCLUSION

The use of a negative pressure facial antechamber can effectively reduce aerosolization from endoscopic drilling without disturbing the flow of the operation. The antechamber, in conjunction with appropriate PPE, will be useful during the COVID-19 pandemic, as well as during flu season and any future viral outbreaks.