Comparison of the efficacies of 1.0mm and 1.5mm silicone tubes for the treatment of nasolacrimal duct obstruction

Purpose: We compared the difference in postoperative patency rates due to the differences in the diameter of silicone tubes used for bicanalicular intubation for the treatment of nasolacrimal duct obstruction (NLDO). Methods: Patients diagnosed with NLDO at Ehime University Hospital between August 2013 and November 2020 who underwent endoscopic-assisted nasolacrimal duct intubation (ENDI) were included in the study. The patients involved were 130 cases and 157 sides (age 72.6 ± 11.3 years) who were eligible for follow-up for more than six months after the removal of the lacrimal silicone tube. The postoperative recurrence rate was compared retrospectively based on the difference in tube caliber. The patients were divided into two groups: those intubated with a 1.5-mm large diameter tube (Group LD) and those with a 1.0-mm normal diameter tube (Group ND). The survival rates of the two groups at one year after tube removal were compared by Kaplan-Meier's curve and Restricted mean survival time (RMST) method with τ = 365 days. Results: There were no significant differences in age, gender, or observation period after tube removal between the two groups. Meanwhile, the preoperative occlusion period was significantly longer in the ND group. The recurrence rate after tube removal was significantly lower in the LD group (12 / 85 sides, 14.1%) compared to the ND group (27 / 72 sides, 37.5%) (p = 0.001). The patency rate at one year after removal of the lacrimal tube was 0.857 (0.754-0.919) in the LD group and 0.739 (0.617-0.828) in the ND group. In comparing patency rates by the RMST method at τ = 365 days, the RMST difference, RMST ratio, and RMTL ratio were significantly higher in the LD group at p = 0.045, 0.052, and 0.046, respectively. Conclusion: Regarding the bicanalicular silicone tube intubation, the patency rate at one year after removal was significantly higher in the thicker tubes with a diameter of 1.5 mm compared with that of a diameter of 1.0 mm for the treatment of NLDO.

Dielectric Elastomer Fiber Actuators with Aqueous Electrode

Dielectric elastomer actuators (DEAs) are one of the promising actuation technologies for soft robotics. This study proposes a fiber-shaped DEA, namely dielectric elastomer fiber actuators (DEFAs). The actuator consisted of a silicone tube filled with the aqueous electrode (sodium chloride solution). Furthermore, it could generate linear and bending actuation in a water environment, which acts as the ground side electrode. Linear-type DEFA and bending-type DEFA were fabricated and characterized to prove the concept. A mixture of Ecoflex 00–30 (Smooth-On) and Sylgard 184 (Dow Corning) was employed in these actuators for the tube part, which was 75.0-mm long with outer and inner diameters of 6.0 mm and 5.0 mm, respectively. An analytical model was constructed to design and predict the behavior of the devices. In the experiments, the linear-type DEFA exhibited an actuation strain and force of 1.3% and 42.4 mN, respectively, at 10 kV (~20 V/µm) with a response time of 0.2 s. The bending-type DEFA exhibited an actuation angle of 8.1° at 10 kV (~20 V/µm). Subsequently, a jellyfish-type robot was developed and tested, which showed the swimming speed of 3.1 mm/s at 10 kV and the driving frequency of 4 Hz. The results obtained in this study show the successful implementation of the actuator concept and demonstrate its applicability for soft robotics.

A New Modification in Endoscopic Endonasal Dacryocystorhi̇nostomy: Scopy-Guided Approach

PurposeTo compare and assess classic endoscopic dacryocystorhinostomy (cEDCR) and scopy-guided endoscopic dacryocystorhinostomy (sEDCR) which is a new approach we developed in cases of primary nasolacrimal duct obstruction (PNLDO).MethodsFifty eyes (7 in both eyes) of 43 patients who applied with epiphora and underwent endoscopic DCR and silicone tube implantation between 2015 and 2019 were prospectively studied. cEDCR was performed on 26 of 50 eyes, and sEDCR was performed on 24 of 50 eyes. In sEDCR application, 5 cc non-ionizing opaque material was injected after punctum dilatation, lateral oblique radiographs were taken from the obstructed side with C-arm scope, and the size and location of the lacrimal sac were made visible. Thence, the most appropriate part of the passage was visualized, and surgical intervention was made through this point. Patients were followed in day 1, week 1, 3rd and 6rd mounth. Functional success was assessed according to Munk scoring, and anatomic success was assessed with nasolacrimal lavage. Two groups were compared according to surgical success, time, and complications.ResultsMean age of the cases were 47.85 (±11.8) in the cEDCR group and 54.29 (±16.23) in the sEDCR group. Female and male gender distribution was 21 (80.8%) - 5 (19.2%) for cEDCR and 15 (62.5%) - 8 (37.5%) for sEDCR, respectively. Functional success was spotted as 92.3% in the cEDCR group and 95.8% in the sEDCR group (p:1.0); anatomical success was spotted as 88.5% in the cEDCR group, and 95.8% in the sEDCR group (p:0,611). There was no significant difference between two groups. Mean surgery time was 43 minutes in the cEDCR group and 48 minutes in the EDCR group. Complications were minor and rare (p >0.05). ConclusionAs we are aware of that, our study is the first in literature in which scopy is used in endoscopic DCR. In our study, the sEDCR approach is assessed as a useful modification which improves success and facilitates surgery.

Changes of Tears MCP-1 Level After External Dacryocystorhinostomy in Primary Acquired Nasolacrimal Duct Obstruction

Purpose: To define tears MCP-1 changes after uncomplicated external dacryocystorhinostomy with bicanalicular silicone tube intubation surgery.Methods: In this prospective, longitudinal study, we included patients diagnosed with primary acquired nasolacrimal duct obstruction and underwent dacryocystorhinostomy with bicanalicular silicone tube intubation surgery. Tears samples were collected with a Schirmer strip placed lateral conjunctival cul-de-sac and stored in Eppendorf tubes at -80°C. At the end of the study, they were taken out of the -80°C cabinet and brought to room temperature. The papers were cut into small pieces and incubated in 2 milliliters tubes with phosphate-buffered saline solution in a shaker at 100 revolutions per minute. Then they were centrifuged at 1.000 revolutions per minute for 5 minutes. MCP-1 levels were determined by using an ELISA kit. Results: Of the patients, 14 (56%) were female, and 11 (44%) were male. The mean age was 52.7±10.3 years (ranged from 30 to 63 years). The MCP-1 levels were 498.66±101.35 ng/L, 576.40±149.78 ng/L, 422.53±85.94 ng/L, 436.96±81.38 ng/L before surgery, in the first week, the first and third months after surgery, respectively. The mean MCP-1 level significantly increased in the first week compared to the preoperative level (p < 0.001). In the postoperative first month, there was a prominent decrease (p < 0.001). In the third postoperative month, the mean MCP-1 level was not significantly increased compared to the postoperative first month (p=0.196).Conclusion: The tears MCP-1 level was significantly decreased after uncomplicated external dacryocystorhinostomy with bicanalicular silicone tube intubation surgery

Do Flexible Silicone Tubes Immersed in Water Combined With Vocalise Improve the Immediate Effect on Voice?

Purpose: This study aimed to analyze the immediate effect on a singer's voice of a flexible silicone tube immersed in water combined with ascending and descending vocalise scales compared with ascending and descending vocalise scales alone. Method: A pre- and post-intervention quasi-experimental study was conducted. Thirty adult singers between 18 and 45 years old with no laryngeal disorders performed the two techniques for 3 min each on different days. Acoustic measurements of frequency, jitter, shimmer, glottal-to-noise excitation ratio, noise, smoothed cepstral peak prominence (CPPS), maximum phonation time (MPT), voice range profile, and self-perceived vocal effort (Borg Category Ratio 10-BR Scale adapted for vocal effort) were assessed before and after performing the techniques. Results: The results indicated an increase in singers' CPPS and MPT values and a decrease in shimmer and noise when performing with a flexible silicone tube immersed in water combined with vocalise. The singers reported a perception of decreased vocal effort after both methods. However, the diminished perceived vocal effort became more pronounced with the tube phonation technique combined with vocalise. Conclusions: Phonation in tubes combined with vocalise improved the vocal acoustic parameters (including cepstral measurements), increased MPT, and diminished perceived vocal effort. Although using vocalise alone diminished perceived vocal effort, this decrease was more pronounced in the tube phonation technique combined with vocalise.

Silicone tube humidity generator

We describe the model and construction of a two-flow (or divided-flow) humidity generator, developed at LNE-CNAM, that uses mass flow controllers to mix a stream of dry gas with a stream of humid gas saturated at 28 °C. It can generate a wide range of humidity, with mole fractions in the range 0.7 × 10−6 < x < 9000 × 10−6, without using low temperature or high pressure. This range is suitable for calibrating balloon-borne instruments that measure humidity in the stratosphere, where x ~5 × 10−6. The generator’s novel feature is a saturator that comprises 5 m of silicone tubing immersed in water. Water enters the humid gas stream by diffusing through the wall of the tubing until the gas stream flowing through the tubing is saturated. This design provides a simple, low-cost humidity generator with an accuracy that is acceptable for many applications. The key requirement is that the tubing be long enough to ensure saturation, so that the saturator’s output is independent of the dimensions and permeability of the tube. A length of only a few meters was sufficient because the tube was made of silicone; other common polymers have permeabilities that are 1000 times smaller. We verified the model of the transition from unsaturated flow to saturated flow by measuring the humidity while using three tube lengths, two of which were too short for saturation. As a more complete test, we used the generator as a primary device after correcting the calibrations of the mass flow controllers that determined the mixing ratio. At mole fractions 50 × 10−6 < x < 5000 × 10−6, the generator’s output mole fraction xgen agreed to within 1 % with the value xcm measured by a calibrated chilled-mirror hygrometer; in other words, their ratio fell in the range xgen/xcm = 1.00 ± 0.01. At smaller mole fractions, their differences fell in range xgen − xcm = ±1 × 10−6.