Home-made masks with filtration efficiency for nano-aerosols for community mitigation of COVID-19 pandemic.

OBJECTIVES: The novel coronavirus disease 2019 (COVID-19) epidemic that emerged in December 2019 has rapidly evolved in recent months to become a worldwide and ongoing pandemic. Shortage of medical masks remains an unresolved problem. This study aims to investigate the filtration efficiency (FE) of home-made masks that could be used as alternatives for community mitigation of COVID-19. STUDY DESIGN: Experimental observational analytic study. METHODS: The FE of home-made masks and medical masks (as the control) were tested under laminar flow within a scaled air duct system using nebulised NaCl aerosols sized 6-220 nm. The size-resolved NaCl aerosol count was measured using a scanning mobility particle-sizer spectrometer. Home-made masks with an external plastic face shield also underwent a splash test. In addition, the fibre structures of medical masks were studied under an electron microscope after treatment with either 75% alcohol or soap and water at 60 °C. RESULTS: The FE of the home-made masks at 6-200 nm were non-inferior to that of medical masks (84.54% vs 86.94%, P = 0.102). Both types of masks achieved an FE of 90% at 6-89 nm. A significantly higher FE was achieved when one piece of tissue paper was added adjacent to the inner surface of the medical mask than medical mask alone (6-200 nm: 91.64% vs 86.94%, P < 0.0001; 6-89 nm: 94.27% vs 90.54%, P < 0.0001; 90-200 nm: 82.69% vs 73.81%, P < 0.0001). The plastic face shield prevented the home-made mask from fluid splash. The fibre structures of the external surface of medical masks were damaged after treatment with either 75% alcohol or soap and water at 60 °C. CONCLUSIONS: The home-made masks in this study, which were made of one piece of tissue paper and two pieces of kitchen towels, layered from face to external, had an FE at 6-200 nm non-inferior to that of medical mask materials, which had a certified FE of ≥95% at 3 µm. In the current COVID-19 pandemic with the shortage of medical masks, these home-made masks combined with an external plastic shield could be used as an alternative to medical masks for community mitigation. In addition, one piece of tissue paper could be placed adjacent to the inner surface of a medical mask to prolong effective lifespan of the medical mask. These demand reduction strategies could be used to reserve medical masks for use in healthcare and certain high-risk community settings, such as symptomatic persons, caregivers and attendees to healthcare institutions.

Does the use of monopolar energy as the preferred mode of dissection effectively reduce seroma formation in laparoscopic total extra peritoneal hernioplasty? A prospective double-blinded randomized control trial.

INTRODUCTION: Seroma is a commonly encountered sequela after hernia repair. Tremendous effort has been spent to investigate the effective way to prevent this "complication" including the modification of surgical technique, use of per-peritoneal drainage, etc. There were debates about the use of monopolar diathermy versus blunt dissection in laparoscopic TEP in the prevention of seroma formation. This randomized study aims to compare the effects of using 2 techniques in laparoscopic TEP on pre-peritoneal drain output and seroma formation. METHOD: From 1.9.2018 to 30.9.2019, all male and female patients presented with the first occurrence, unilateral inguinal hernia anticipated for laparoscopic TEP were enrolled into the study after informed consent. Patients were randomized into "monopolar dissection preferred" (MDP) group and "blunt dissection-preferred" (BDP) group just before commencing of operation after general anesthesia. Surgeons were instructed to use monopolar energy as main dissection method for the whole operation if possible (MDP), whereas blunt dissection is the preferred choice in BDP group, but the use of monopolar energy was allowed if needed. Total energy time was measured by a specially designed homemade device attaching to the monopolar pedals as accurate as to millisecond (ms). Pre-peritoneal drains were inserted for drainage and removed 23 h after operation. Drainage output, total operating time, energy time, clinical and ultrasonic seroma sizes at day 1, day 6, 1-month post operations, recurrence are compared between 2 groups. RESULTS: A total of 103 patients where included. There was no significant difference in age, gender, co-morbidities, side of hernia, mean defect size, operating time, fixation adjuncts, or postoperative stay. The drain volume in BDP group is 71.13 ± 31.42 mL while it in MDP group is 56.36 ± 21.46 mL. The MDP group had significantly fewer drain output at 23 h post operation (p = 0.007) and lower seroma incidence on days 6 (p = 0.036). Overall incidence of seroma formation was 12% on postoperative day 1, 11% on postoperative day 7. No statistically differences in postoperative pain score or complications were observed at the first week, 1- and 3-months' post operation. There was no correlation with energy time to the drain output. No recurrence was found in subsequent follow-up. CONCLUSION: Pre-peritoneal drainage is clinically safe in laparoscopic totally extra-peritoneal hernioplasty and can effectively reduce the size and incidence of seroma. The seroma formation can be further reduced by appropriate use of monopolar energy as preferred dissection approach in lap TEP. Due to limitation in measuring the actual energy time, the result should be further validated by randomized multi-centers trial on its potential benefit in hernia repair by a more accurate measuring device on energy used.

Preperitoneal closed-system suction drainage after totally extraperitoneal hernioplasty in the prevention of early seroma formation: a prospective double-blind randomised controlled trial.

OBJECTIVES: Seroma is a virtually unavoidable early sequela after TEP hernioplasty. This randomised controlled trial evaluated the outcomes of preperitoneal closed-system suction drainage in laparoscopic totally extraperitoneal (TEP) hernioplasty for inguinal hernia. METHODS: Ninety patients aged 18-80 years who presented to our hospital between May 2016 and February 2017 with primary unilateral inguinal hernia were randomised into the preperitoneal drain and no-drain groups. The primary outcome was seroma size on postoperative day 6. Secondary outcomes included clinical seroma formation and seroma size on day 1, day 6, 1 and 7 months postoperatively, length of postoperative stay, pain score, and recurrence. RESULTS: There was no significant difference in age, sex, co-morbidities, hernia side, mean hernia size, operating time, fixation adjuncts, or postoperative stay. The overall incidence of clinical seroma formation was 25.6% on postoperative day 1, 60.3% on postoperative day 6, 13.2% 1 month and 0% 7 months postoperatively. The mean drain output was 57.9 ml. The drain group had significantly fewer patients with seroma on day 1 (6 vs 14, p = 0.022) and day 6 (17 vs 30, p = 0.000), and a smaller mean seroma size on days 1 and 6 (p = 0.000). Subgroup analysis showed that sac ligation versus reduction, peritoneal perforation, and fixation adjuncts had no significant effects on seroma formation or size. There is a trend of lower early post-operation VAS score and more urinary retention in drain group was observed but not reaching statistical significance. No differences in postoperative pain score or complications were observed at 1 and 7 months' post operation. CONCLUSIONS: Preperitoneal drainage for 23 h after laparoscopic TEP hernioplasty for inguinal hernia can effectively decrease seroma formation in the early postoperative period, and potentially improving postoperative pain. The benefit is short-term and no significant difference was demonstrated after 1-month post operations. This tradition technique applied to novel operative repair of inguinal hernia is safe and feasible with no significant morbidity demonstrated. Preperitoneal drainage after TEP can be considered as an option to improve patient satisfactions and recovery in selected patient group for maximal benefit, especially for those with prolonged operation which may associate with higher chance of seroma formation.

Randomized trial comparing self gripping semi re-absorbable mesh (PROGRIP) with polypropylene mesh in open inguinal hernioplasty: the 6 years result.

OBJECTIVES: The use of absorbable polylactic acid hook self-gripping polypropylene mesh in open inguinal hernia may potentially reduce operative time and enhance patient recovery. The objective of this randomized trial is to compare the outcomes following self-gripping mesh repair to polypropylene mesh secured with sutures in open inguinal hernioplasty. METHOD: Eligible patients aged 18-80 years old, who had primary unilateral uncomplicated inguinal hernia, were randomized into either Polypropylene (PL) group or PROGRIP (PG) group just before the placement of mesh intra-operatively by computer generated code. The primary outcome was the time from mesh placement to end of operation, whereas secondary outcomes included the total operative time, amount of analgesic used, length of post-operative stay, seroma formation, chronic discomfort, chronic pain score and recurrence. The study has been registered in http://www.clinicaltrial.gov carrying an ID of NCT00960011. Patients were followed-up in outpatient clinic for up to 6 years after operation. RESULTS: From March 2009 to April 2016, 45 patients were included. The mean age of PG group (n = 22) was 62.0 ± 15.7 years old while that of the PL group was 62.6 ± 4.9 years old (n = 23). There was no significant difference regarding the smoking habit, drinking habit, comorbidities, previous hernia operation and Nyhus type of hernia between the two groups. The size of defects, the time of groin dissection and the size of incision were similar. In the PG group, there was significant reduction in the time for mesh placement (11.8 ± 3.1 vs. 21.0 ± 6.2 min, p < 0.001) and total operative time (39.2 ± 9.8 vs. 47.7 ± 8.0 min, p = 0.003). There was one recurrence in PL group and nil in PG group. Although there was a significant difference in paresthesia between 2 groups after operation, the difference disappears with time and comparable from post-operative 1 year onwards. There was no difference in chronic pain, chronic discomfort, affect daily activities, palpable mesh demonstrated throughout the whole study period till 6 years after operation. CONCLUSIONS: The use of polylactic acid self-gripping mesh in open inguinal hernia repair effectively reduces the operating time with comparable long-term surgical outcome with traditional polypropylene mesh.

Refining the continuous tracking paradigm to investigate implicit motor learning.

In two experiments we investigated factors that undermine conclusions about implicit motor learning in the continuous tracking paradigm. In Experiment 1, we constructed a practice phase in which all three segments of the waveform pattern were random, in order to examine whether tracking performance decreased as a consequence of time spent on task. Tracking error was lower in the first segment than in the middle segment and lower in the middle segment than in the final segment, indicating that tracking performance decreased as a function of increasing time-on-task. In Experiment 2, the waveform pattern presented in the middle segment was identical in each trial of practice. In a retention test, tracking performance on the repeated segment was superior to tracking performance on the random segments of the waveform. Furthermore, substitution of the repeated pattern with a random pattern (in a transfer test) resulted in a significantly increased tracking error. These findings imply that characteristics of the repeated pattern were learned. Crucially, tests of pattern recognition implied that participants were not explicitly aware of the presence of a recurring segment of waveform. Recommendations for refining the continuous tracking paradigm for implicit learning research are proposed.

Prognostic value of lymph node ratio in stage III colorectal cancer.

AIM: Recent reports show that a positive metastatic to examined lymph nodes ratio (LNR) has prognostic value in malignancies. This study aimed to evaluate the prognostic value of LNR in patients having resection for stage III colorectal cancer. METHOD: From January 2000 to December 2006, patients who underwent resection for stage III colorectal carcinoma were included. All clinicopathological and follow-up data were prospectively collected. The impact of LNR and other clinicopathological factors on survival were evaluated. RESULTS: The study included 533 (52.3% male) patients with a median age of 70 years. The median number of lymph nodes harvested and the median number of positive lymph nodes examined were 11 and 2, respectively. The median LNR was 0.263 (range, 0.03-1). After a median follow up of 52.65 months, the 5-year overall survival and disease-free survival were 55.9% and 49.4%. The patients were stratified into four groups according to LNR quartiles (1, LNR ≤ 0.125; 2, 0.1250.500). The 5-year overall and disease-free survival were 72.8%, 63.1%, 50.0%, 39.6% (P<0.001) and 68.5%, 54.1%, 47.2%, 29.9% (P<0.001), respectively, with increasing LNR groups. On multivariate analysis, age, T stage and LNR were independent predictors of both overall and disease-free survival. Subgroup analysis revealed that the LNR had a prognostic value for disease-free survival irrespective of number of lymph nodes harvested and location of tumour. CONCLUSION: The LNR is an independent prognostic factor for survival in colorectal cancer and is superior to the pN category in TNM staging.

Single incision laparoscopic left colectomy for carcinoma of distal transverse colon.

OBJECTIVE: We report a single-incision laparoscopic left colectomy for a patient with a distal transverse colon cancer. METHOD: A 78-year-old man with carcinoma of the transverse colon close to the splenic flexure underwent a single-incision laparoscopic left colectomy with full mobilization of splenic flexure using the TriPort Access System and ordinary laparoscopic instruments. RESULTS: The operation was successfully performed. The patient recovered uneventfully and was discharged after 3 days. Histopathological examination showed a T3N1 tumour with clear resection margins. CONCLUSION: This case demonstrates that single-incision laparoscopic colectomy can be applied safely to large bowel cancer close to the splenic flexure. The technique warrants further investigation.

Outcome of laparoscopic colorectal resection.

It has been nearly two decades since the first laparoscopic colectomy was reported. However, the wide application of the procedure in various colorectal diseases, particularly colorectal malignancy, has been slow. With the recent reports ofoncological outcomes from randomised controlled trials, the oncological safety of laparoscopic colectomy has been proven and the long-term outcome is at least not inferior to open resection. The application of laparoscopic resection should not be regarded as a contraindication against management of colon cancer, but instead it appears the preferred treatment when the short-term benefits are considered. Regarding rectal cancer, the CLASICC (Conventional versus Laparoscopic-Assisted Surgery in Colorectal Cancer) trial showed equal oncological outcome in patients who underwent laparoscopic and open resection for rectal cancer in a randomised trial. The application of laparoscopic resection for rectal cancer should be accepted, though cautions are still needed to scrutinise more data from high quality studies.