Laser Therapy in Maintenance of the Patency of Expandable Metal Stents

Re-establishment of the oesophageal lumen is the main focus of care in patients with dysphagia due to re-blockage of in situ expandable metal stent (EMS). A total of 51 patients aged 44–89 years were intubated with EMS for dysphagia due to inoperable oesophagogastric carcinoma. Of these patients, 25 required follow-up endoscopy at variable intervals after stent insertion; 17 patients were found to have significant tumour in-growth (9), overgrowth (4) or both (4). All these patients were treated with Nd-YAG (70 W/s) or diode laser (30–50 W, continuous) for maintenance of satisfactory swallowing. The intensity of tumour ablation was similar with both types of lasers but four patients being treated with Nd-YAG laser developed deformity of EMS. This complication was not encountered with diode laser. The timing of the stent insertion should be carefully chosen since the longer the stent is in situ, the greater is the likelihood of tumour ingrowth or overgrowth. The combination of endoscopic laser therapy (ELT) and EMS may offer the best palliation, particularly when patient survival of several months is anticipated. ELT can effectively deal with tumour in-growth and overgrowth but care must be exercised in the use of Nd-YAG which can damage the structure of the EMS. Paper received 23 December 1997; accepted after revision 12 May 1998.     

Early Experiences of Haemostasis on Brain Tumour Surgery with Argon Plasma Coagulation (APC)

Summary  Objective. We first applied a novel haemostatic strategy involving Argon Plasma Coagulation (APC), an innovative no-touch electrocoagulation technique in which a high-frequency alternating current is delivered to the tissue through ionized argon gas, to brain tumour surgery, and report its usefulness and limitations.  Methods. The APC system we used comprised an APC 300 developed by ERBE Elektromedizin GmbH, Germany. We applied APC to 13 brain tumours in 12 patients (5 meningiomas, 4 sarcomas, 2 glioblastomas, and 2 pituitary adenomas). To avoid unnecessary thermal injury to the tissue as much as possible, power/gas flow settings of 20 and 40 W were used. The impact time was varied individually but was around several seconds per one impact. The argon jet (1.5–4.5 L/min) clears a field of pooled blood and evenly conducts electrical energy to the target tissue. A thin and flexible probe particularly increased the usefulness of APC for haemostasis on deep-seated skull base tumour operations under a microscope.  Conclusion. All patients were successfully treated and satisfied with the surgical results without any complications due to APC. APC appears to be an excellent alternative strategy for achieving haemostasis on vascular-rich brain tumour surgery, and may be valuable for the management of patients with coagulation defects.     

Diffusing Fibre Tip for the Minimally Invasive Treatment of Liver Tumours by Interstitial Laser Coagulation (ILC): An Experimental Ex Vivo Study

A newly developed diffusing laser applicator was examined for interstitial laser coagulation (ILC) of liver tumours. The applicator consisted of a matted quartz core and a quartz glass dome, also matted on its inner surface and sealed to the fibre. The applicator provided a homogeneous light intensity distribution over an active length of about 20 mm. Lesions were created in an ex-vivo porcine liver model using a Nd-YAG laser comparing the new diffusing tip with a Ringmode^?-ITT applicator in order to find optimal laser parameters and damage thresholds. The lesions were investigated using macroscopic size measurement, volume calculation and histological examination (H&E, NADPH-dehydrogenase). The damage threshold of the diffusing tip was 6 W at 14 min exposure time whereas the Ringmode^?-ITT applicator had its limit at 5 W and 12 min exposure. Comparing various exposure times showed that treatment over a time of more than 840 s did not significantly increase the lesion volume. At 5 W and 720 s the mean lesion volume was 6.9±1.1 cm³ with the diffusing tip and 6.3±0.6 cm³ with the Ringmode^?-ITT applicator, both having a slight ellipsoidal shape. Hence, the created lesions were not significantly different for both applicators when the same laser parameters were applied. On the other hand, the new diffusing tip had a higher damage threshold and was therefore capable of producing maximal coagulation volumes of up to 7.9±0.5 cm³ at 5 W and 20 min. The experiments showed that lesions with a dimension of 31×22 mm can be achieved with the diffusing applicator which seem suitably sized for treating small human liver metastases in a single laser session. Paper received 25 April 1997; accepted after revision 13 March 1998.     

Concomitant Therapy of Oral Isotretinoin with Multiplex Pulsed Dye Laser and Nd: YAG Laser for Acne

ObjectiveTo evaluate concomitant therapy of oral isotretinoin with multiplex pulsed dye laser and Nd:YAG laser.MethodsA retrospective chart review of patients who received treatment of oral isotretinoin and non-ablative laser therapy to treat acne vulgaris at a single outpatient dermatology clinic site in Ontario, Canada between 2009 and 2017. Results187 patients were included, consisting of 45.5 percent males (n=85) and 54.5 percent females (n=102) with a mean age of 21.4 years. 31.6 percent (n=59) of patients reported experiencing side effects from concomitant isotretinoin and NAL therapy, the most common being eczema (n=14), erythema (n=11), significant dry skin/lips/eyes (n=8), flushing (n=6), and bruising (n=6). 99.2 percent of patients achieved clear or almost clear at treatment completion. Of those who expressed satisfaction, 65.2 percent (n=122) reported being satisfied with the treatment and the remaining patients did not report satisfaction nor dissatisfaction.Limitations Limitations exist mainly due to the absence of standardized lesion counts and a comparator cohort. Thus, it is not possible to comment on whether the combination of isotretinoin and NAL is more efficacious that either treatment alone.ConclusionConcomitant use of isotretinoin and non-ablative laser therapy is a safe and effective treatment option for acne vulgaris that provides patient satisfaction.     

Resurfacing of Pitted Facial Acne Scars Using Er:YAG Laser with Ablation and Coagulation Mode

Although the conventional, short-pulsed erbium: yttrium-aluminum-garnet (Er:YAG) laser provides substantial clinical improvement for pitted, facial acne scars, it shows less effective hemostasis and limited residual thermal effect in the dermis. Recently, dual-mode Er:YAG laser systems with both ablation and coagulation modes have been developed. The purpose of this study was to evaluate the clinical and histologic effects of resurfacing pitted, facial acne scars with a dual-mode Er:YAG laser. Twenty patients with pitted facial acne scars underwent laser resurfacing using a computerized-scanning, dual-mode Er:YAG laser. All patients had Fitzpatrick skin types ranging III–V. Initially, the epidermis was removed in two passes using the ablative settings. This step was followed by two passes in a mixed ablation and coagulation mode, to produce further ablation and controlled, residual thermal damage. A final pass in a ablation mode was used to remove necrotic tissue. Laser overlapping was approximately 30%. The results of laser treatment were evaluated for the degree of clinical improvement, duration of erythema, pigmentary change, and any adverse events at two weeks, one month, and three months. In two patients, skin biopsies were obtained at the following intervals: immediately and two weeks postoperatively for histologic examination. There was a 75% average clinical improvement observed in pitted, facial acne scars after laser treatment. Complete wound healing occurred between six and eight days. On histologic examination, complete re-epithelialization was observed at two weeks. Erythema occurred in all patients after laser treatment and lasted longer than three months in 10 patients (50%). Post-inflammatory hyperpigmentation occurred in 12 patients (60%) two to four weeks after laser treatment and lasted longer than three months in one patient (5%). One patient (5%) experienced mild hypopigmention. Mild to moderate, postoperative acne flare-up occurred in seven patients (35%). No other adverse effects were observed. In conclusion, resurfacing with a dual-mode Er:YAG laser is a safe and effective treatment modality for pitted, facial acne scars.     

Comparative In Vitro Study of the Bond Strength of Composite to Enamel and Dentine Obtained with Laser Irradiation or Acid-etch

. The shear bond strength of composite resin on enamel and dentine was compared after acid-etch or irradiation by Er:YAG and Nd:YAP lasers. Forty-eight extracted molars were selected. Dentine and enamel samples were prepared by buccal and lingual surface sectioning to expose a plane enamel or dentine surface. Samples (n=12) were randomly assigned to eight groups. In groups 1 and 5, enamel and dentine surfaces were etched with a 37% phosphoric acid solution. In groups 2 and 6, surfaces were irradiated by Er:YAG laser at an energy of 200 mJ and 4 Hz for enamel and 140 mJ and 4 Hz for dentine. In groups 3 and 7, irradiation was performed by Nd:YAP laser at 310 mJ and 10 Hz for enamel and 240 mJ and 10 Hz for dentine. Groups 4 and 8 served as controls. A cone of composite was bonded perpendicularly onto the prepared surfaces using the Scotch Bond Multipurpose adhesive system. Each sample was then stored in physiological serum at 37°C for one week and thermocycled. Shear bond strength was determined on a universal testing machine. Composite–enamel and composite–dentine interfaces were examined by scanning electron microscopy and microanalysis. Shear bond strength was greater on dentine and enamel after acid-etch than laser radiation. These treatments could be ranged in the following order: acid-etch, laser Er:YAG and laser Nd:YAP. Differences between groups were significant for enamel, whereas no significant differences were found for dentine between acid-etch and Er:YAG laser-irradiation (Kruskal–Wallis test). Thus, laser preparation did not improve bonding to enamel and dentine. Paper received 14 August 1998; accepted following revision 11 January 1999.     

An In Vitro and In Vivo Study of Cytokines in the Acute-Phase Response Associated with Bisphosphonates

We studied the acute phase response, including specific cytokine production, [interleukin-1 (IL-1), interleukin-6 (IL-6), tumor necrosis factor α(TNFα)] following a single dose of Aredia (disodium pamidronate) in patients with increased bone turnover and, in vitro, the role played by specific cytokines in the acute-phase reaction which may follow the administration of aminobisphosphonates. An in vivo exploratory study was done on 24 in- and outpatients with increased bone turnover given a single intravenous dose of pamidronate 60 mg. Measurements were taken at baseline and at 24, 48, and 72 hours. The main outcome measures were changes from baseline in serum IL-1, IL-6, and TNFα. In addition, C-reactive protein (CRP), white blood cell count (WCC), lymphocyte count, and elastase concentration were measured. Symptomatic evaluation was made of fever, bone pain, and rigors. In vitro, whole blood from eight healthy volunteers was exposed to various concentrations of the three bisphosphonates—pamidronate, clodronate, and zoledronate. Measurements were taken immediately before and at 3, 6, and 10 hours after exposure to drugs. The main outcome measures were changes in serum IL-1, IL-6, and TNFα. In vivo, there was a statistically significant (P < 0.001) increase in median values of TNFα in all post-baseline measurements. Median values for IL-6 also showed a significant (P < 0.001) increase at 24 hours after dosing. There were no statistically significant changes in median IL-1 values. Few patients showed any change from baseline in total WCC or in lymphocyte count, but 62.5% of patients with normal range baseline values for CRP increased to above normal levels after treatment. Fourteen patients experienced fever; 2 reported rigors. There was no correlation between fever and changes in cytokines. There were no serious adverse experiences or premature discontinuations due to poor tolerability, and 91% of the patients expressed willingness to receive pamidronate again. In vitro, an increase in TNFα and a mild increase in IL-6 was seen with all bisphosphonates, with the greatest effects seen with the highest concentration of both pamidronate and zoledronate. No changes were observed in IL-1 with any agent. Significant changes in both TNFα and IL-6 were observed within 3 days of a single dose of pamidronate in patients treated for the first time confirming previous findings. However, the lack of change in IL-1 in vivo and in vitro does not support the hypothesis that this cytokine plays a major role in the acute phase reaction. The cellular mechanism of the interaction among aminobisphosphonates, Il-6, and TNFα requires further investigations. The results of the in vitro study are consistent with the in vivo findings. Received: 30 September 1996 / Accepted: 21 May 1997     

Endoscopic Nd:YAG Laser Therapy Combined with Local Chemotherapy of Superficial Carcinomas of the Oesophagus and Gastric Cardia

The aim of this study was to explore the possibilities of non-surgical management for superficial carcinomas of the oesophagus and gastric cardia. Thirty-one patients with superficial oesophageal or gastric cardiac carcinomas, who refused or were unsuitable for surgery, received endoscopic Nd:YAG laser therapy combined with local injection of chemotherapeutic drugs 5-fluorouracil and mitomycin. After one to four sessions of treatment no cancer cells were detected by multiple biopsies and no complications such as bleeding or perforation occurred in any case. The 31 patients have been followed-up for 25–91 months (five cases for 91 months, eight cases for 79 months, four cases for 55 months, eight cases for 33 months and six cases for 25–31 months). All patients are surviving without sign of recurrence and no cancer cells were detected by endoscopic biopsies. Our findings indicate that this is an effective and safe therapeutic modality and may be considered as the first choice for those patients who refuse or are not suitable for surgery, and for those of older age and in poor condition. Paper received 16 November 1999; accepted after revision 21 March 2001.     

Holmium: YAG Laser Resection of the Prostate Versus Visual Laser Ablation of the Prostate and Transurethral Ultrasound-Guided Laser Induced Prostatectomy: A Retrospective Comparative Study

Background:
Transurethral resection of the prostate (TUR-P) is the gold standard for treating symptomatic benign prostatic hyperplasia (BPH) despite some perioperative morbidity. As a minimally-invasive alternative to TUR-P, a neodymium:YAG laser, and more recently a holmium:YAG laser, have been used in transurethral surgery for BPH. In order to assess the safety and efficacy of various BPH treatments, the outcome in patients treated with transurethral ultrasound-guided laser induced prostatectomy (TULIP), visual laser ablation of the prostate (VLAP) and holmium:YAG laser resection of the prostate (HoLRP) were retrospectively compared.
Methods:
From May 1995 to August 1996, 60 patients with symptomatic BPH underwent TULIP (n=20), VLAP (n=20), and HoLRP (n=20). All patients were evaluated preoperatively and at 1 and 3 months postoperatively by the International Prostate Symptom Score (IPSS), the IPSS quality-of-life score (QOL), maximum flow rate (MFR), prostate volume, and residual urine volume.
Results:
The preoperative mean IPSS was 18.5, 19.3, and 19.6 and the mean MFR was 6.3, 6.9, and 6.1mL/sec in the TULIP, VLAP, and HoLRP groups, respectively. At 1 month after surgery, the mean IPSS was 10.2, 9.5, and 4.7 and the mean MFR was 9.6, 1 3.4, and 1 8.7mL/sec while at 3 months the mean IPSS was 6.2, 6.1, and 3.6 and the mean MFR was 14.1, 1 6.0, and 21.5 mL/sec in patients treated with TULIP, VLAP, and HoLRP, respectively. No serious complication occurred in any patient.
Conclusion: Although HoLRP requires expertise, it appears to be a promising treatment modality for BPH.     

Prediction of Human Femoral Bone Strength Using Ultrasound Velocity and BMD: An In Vitro Study

The stiffness and strength of cancellous bone are important in the management of skeletal diseases such as osteoporosis. These properties are a function not only of bone density but also of bone architecture, some measure of which can be provided by quantitative ultrasound. The ability of quantitative ultrasound and bone mineral density (BMD) to predict stiffness and strength of human femoral heads removed from live subjects during hip replacement was assessed. Stiffness and strength were measured using a uniaxial compression test. Ultrasound velocity was measured using the pulse-submersion technique (McClue CUBAResearch) and BMD using DXA (Lunar DPX-L). Ultrasound velocity (quantitative ultrasound) and stiffness varied with the three orthogonal directions, the highest significance being between the proximo-distal (PD) and antero-posterior (AP) directions (p < 0.0001) for stiffness and p = 0.0003 for velocity). Ultrasound velocity was significantly correlated with compressive bone strength (r = 0.76, p < 0.0001) and stiffness (r = 0.79–0.83, p < 0.0001). BMD was also significantly correlated with compressive strength (r = 0.82, p < 0.0001) and stiffness (r = 0.66–0.81, p < 0.001). Using multiple regression analysis both BMD and velocity were significant predictors of strength (r = 0.88, p = 0.0004 and 0.0054 respectively) and stiffness r = 0.92, p = 0.0001 and 0.0003 respectively). BMD and velocity were still independent significant predictors of both stiffness (r = 0.93, p < 0.0001 and 0.0001 respectively) and strength (r = 0.89, p < 0.0001 and 0.02) when they combined as a product (BMDⁿ*V^m). This suggests that BMD measured using DXA, if used in conjunction with ultrasound velocity, may be able to improve osteoporosis risk assessment. The information about femur anisotropy may also be important for hip prosthesis and in vivo modelling.     

Er:YAG激光联合牙周基础治疗对牙周炎患者病灶区相关指标及红白美学的影响

目的:分析Er:YAG激光联合牙周基础治疗对牙周炎患者牙周指标、龈沟液内炎性因子和内毒素(LPS)含量及红白美学效果的影响。方法:选取2015年12月-2018年12月在北部战区总医院和沈阳市口腔医院接受治疗的慢性牙周炎患者80例,随机分成对照组和观察组。对照组:40例,行牙周基础治疗;观察组:40例,在对照组基础上行Er:YAG激光治疗;观察两组患者临床疗效、出血指数(BI)、探针深度(PD)、菌斑指数(PLI)、临床附着丧失(CAL)及龈沟内液白细胞介素-21(IL-21)、IL-17、肿瘤坏死因子-α(TNF-α)、内毒素(LPS)含量及红白美学效果。结果:观察组和对照组患者总有效率分别为92.50%、77.50%,差异有统计学意义(P<0.05);治疗后8周,观察组患者PLI、PD、BI及CAL较治疗前、对照组降低,差异有统计学意义(P<0.05);治疗后8周,观察组患者龈沟液内TNF-α、IL-17、IL-21及LPS含量较治疗前、对照组降低,差异有统计学意义(P<0.05);治疗后8周,观察组患者WES、PES及PES/WES评分均高于对照组,差异有统计学意义(P<0.05)。结论:Er:YAG激光联合牙周基础治疗可显著缓解患者临床症状,降低牙周炎症反应程度,提升患牙红白美学效果,改善其生活质量。     

Flow Characteristics of the St. Jude Prosthetic Valve: An In Vitro and In Vivo Study

The St. Jude cardiac prosthetic aortic valve was evaluated in vitro and in vivo in an attempt to establish flow characteristics and to correlate them with clinical findings. In vitro, a fluid vehicle (6% Polyol V-10, 32°C) with viscosity similar to blood (0.035 dyne-sec/cm²) was used under conditions of steady flow through a flow chamber simulating the aortic root. Gradient, velocity, and shear stress were measured 5.79 mm, 26.79 mm, 44.79 mm, and 77.79 mm downstream from 25-mm and 27-mm valves using a laser-Doppler anemometer. At 417 ml/sec, the valve gradient was 6.2 mmHg with the 25-mm valve, and 5.2 mmHg with the 27-mm prosthesis. Velocity was maximum at the orifice center, and wall shear stress was low (maximum 600 dyne/cm²). In vivo, six patients with 25-mm St. Jude aortic valves were studied within 48 hours after surgery to determine cardiac output, valve flow, and gradient. The gradient was 3.3 ± 1.9 mmHg (M ± SD) at 249 ± 96 ml/sec and the effective valve area was as large as the geometric area (2.58 vs. 3.09 cm²). Thus, flow through the St. Jude valve is unobstructed and central, has low turbulence, and achieves optimal effective valve area for a given available orifice area.     

In vitro decalcification of aortic valve leaflets with the Er:YSGG laser,Ho:YAG laser,and the cavitron ultrasound surgical aspirator

This study was designed to compare the efficacy of the erbium: yttrium-scandium-gallium-garnet (Er:YSGG) laser and the holmium:yttrium-aluminum-garnet (Ho:YAG) lasers in debriding calcium from freshly explanted aortic valve leaflets and to compare the Er:YSGG laser with the Cavitron ultrasonic surgical aspirator (CUSA). Aortic valve leaflets were freshly explanted from patients undergoing aortic valve replacement for aortic stenosis. Initially, 4 leaflets each were debrided with the Er:YSGG and the Ho:YAG lasers to attempt removal of calcium deposits while preserving the underlying integrity of the leaflets and minimizing thermal damage. The Er:YSGG laser was more effective in doing so with less thermal and photoacoustic damage when compared with the Ho:YAG laser. Twelve more leaflets each were then debrided with the Er:YSGG laser and the CUSA. The Er:YSGG laser again proved less injurious to the underlying leaflet. The CUSA-treated leaflets demonstrated shattering and disruption of adjacent tissue as well as collagen fiber exposure. These changes were not seen with the Er:YSGG laser. Because of these properties, the Er:YSGG laser merits further evaluation as a tool for aortic valvuloplasty procedures in selected patients with senescent calcific aortic stenosis. © 1993 Wiley-Liss, Inc.     

Efficacy and Safety of Q-switched Double-frequency 532-nm Neodymium-doped Yttrium Aluminum Garnet Laser in the Treatment of Lip Hyperpigmentation: A Pilot Study

BackgroundLip hyperpigmentation is a common cosmetic problem with multiple causative factors and limited treatment options.ObjectiveThis study sought to assess the efficacy and safety of Q-switched (QS) double-frequency 532-nm neodymium-doped yttrium aluminum garnet (Nd:YAG) laser therapy for dark lips.MethodsA prospective pilot study of 24 patients with lip hyperpigmenation treated with a QS double-frequency 532-nm Nd:YAG laser was performed. Photographs taken before and three months after the laser therapy sessions were evaluated for improvement and/or any complication by two blinded dermatologists using the color score chart and a visual analog scale (VAS). Patients were asked to assess their pain and satisfaction scores following the procedure using a VAS.ResultsThe mean VAS scores of the photographs decreased by 10.18 percent, from a baseline of 6.09±1.53 to 5.47±1.72 (p=0.16). Also, the color score decreased by 9.38 percent, from 2.44±0.61 to 2.23±0.71 points (p=0.23) after the last treatment. Overall, the photographic assessment indicated that, of the 24 participants, 14 (58.3%) showed moderate to excellent improvement, four (16.7%) showed mild or no improvement, and six (25.0%) showed worsening/mottling of the pigmentation. The overall mean pain and satisfaction scores were 4.08±1.14 and 6.50±2.92, respectively.ConclusionQS Nd:YAG 532-nm laser therapy appears to be a safe and moderately effective treatment for hyperpigmentation of the lips. Further studies should evaluate a larger number of patients and undertake a longer period of follow-up.     

Q开关1064nm Nd:YAG激光联合珍珠美白散治疗黄褐斑疗效探讨

目的:探讨Q开关1064nm Nd:YAG激光联合珍珠美白散治疗黄褐斑的临床疗效。方法:选取2016年4月-2019年4月在笔者医院接受治疗的黄褐斑患者110例作为研究对象,采用随机数字表法将其分为观察组(n=56)和对照组(n=54)。观察组采用Q开关1064nm Nd:YAG激光联合珍珠美白散治疗,对照组采用Q开关1064nm Nd:YAG激光治疗。对比两组临床疗效、皮损总积分、积分下降指数、不良反应率及复发率。结果:治疗后,观察组临床总有效率明显高于对照组(92.86 vs 66.67)%(P<0.05);观察组皮损总积分明显低于对照组(1.27±0.26 vs 2.87±0.38)分,且积分下降指数明显高于对照组(0.66±0.07 vs 0.52±0.06)(P<0.05);观察组不良反应率明显低于对照组(3.57 vs 53.70)%(P<0.05);观察组复发率明显低于对照组(1.79 vs 18.52)%(P<0.05)。结论:Q开关1064nm Nd:YAG激光联合珍珠美白散治疗黄褐斑临床疗效理想,有效改善皮损状况,且对降低复发率及不良反应率效果显著,值得在临床上推广及应用。     

Biomechanical Comparison of Intramedullary Beaming and Plantar Plating Methods for Stabilizing the Medial Column of the Foot: An In Vitro Study

Charcot neuroarthropathy often results in a rocker-bottom foot deformity, which leads to ulceration, infection, and amputation. Surgical techniques to reconstruct the medial column include intramedullary beaming and plantar plating, with disagreement regarding which approach provides a stronger construct with superior stability and fixation. The objective of the present cadaveric study was to compare the construct rigidity and strength of beaming and plantar plating of the medial column of 5 paired bilateral feet. Cannulated titanium beams and plates were implanted in the right and left feet, respectively. The specimens underwent interval testing to generate load-displacement and load-strain curves, cyclic loading at low loads, and then were loaded to failure. The beamed and plated specimens had statistically similar stiffness (p?=?.80) with a mean of 11.1?±?3.9 N/mm and 11.3?±?5.9 N/mm, respectively. The beamed and plated specimens had a statistically similar mean strain of ?164?±?75.1 µε and ?208?±?87.8 µε on the dorsal (p?=?.45) and 92?±?90.4 µε and 221?±?100.5 µε on the plantar (p?=?.08) surfaces of the first metatarsal. Three beamed specimens failed from talus fracture (60%), and 2 beams plastically deformed (40%). Two plated specimens failed from talus fracture (40%), and 3 experienced screw pullout (60%). The beamed and plated specimens withstood a mean load to failure of 234?±?111.4 N and 140?±?68.9 N, respectively, with the difference statistically significant (p?=?.04). Overall, beaming was more robust than plantar plating, because it was less sensitive to specimen size and bone quality.     

An Artificial Neural Network-Based Noninvasive Detector for Suction and Left Atrium Pressure in the Control of Rotary Blood Pumps: An In Vitro Study

Abstract: Rotary blood pumps are used in clinical applications to assist circulation via pumping blood from the left atrium to the aorta. Negative inflow pressures at high flow rates can cause suction of the cannula in the left atrium with deleterious effects on the atrial wall, the blood, and the lung. Therefore, stable and reliable detection of suction and the prediction of the left atrium pressure (LAP) would be of major interest for the control of these pumps. This work reports about an in vitro study of such a detector based on artificial neural networks (ANN). In the first project phase, an ANN was used to estimate the LAP based on pump speed, pump flow, and aortic pressure, obtained from a mock circulation. The inputs for the ANN were 11 characteristic values computed from these three parameters. In the second phase, another ANN was trained to classify various system states, such as suction, danger of suction (a state close to actual suction), and no suction. The first ANN was able to estimate the LAP with an accuracy of ±1.8 mm Hg. The discrimination of suction versus the other two states could be performed with a sensitivity and specificity of about 95% while the more interesting task of distinguishing danger of suction from no suction reached a sensitivity and specificity of about 65% (leaving 25% of each class unclassified and 10% of each class incorrectly classified). The results demonstrate the viability of ANN-based detectors in supporting the control of rotary blood pumps. Improvements, still necessary for in vivo use of such a detector, will most likely come from extending the approach through spatiotemporal ANNs to account for dynamic state changes.     

Q开关Nd:YAG 1 064nm激光联合氨甲环酸片治疗黄褐斑的疗效及对MASI评分的影响

目的:探究Q开关Nd:YAG 1 064nm激光联合氨甲环酸片治疗黄褐斑的疗效及对MASI评分的影响。方法:选取笔者医院2017年2月-2018年10月门诊收治的116例黄褐斑患者,按治疗方案的不同将患者分为对照组和观察组。对照组:51例,采用Q开关Nd:YAG 1 064nm激光治疗;观察组:65例,在对照组治疗的基础上,联合氨甲环酸片治疗。比较两组患者的临床疗效、治疗前后黄褐斑皮损面积和严重度指数(Melasma area severity index,MASI)以及不良反应发生和复发情况。结果:观察组患者治疗后有效率(93.85%)明显高于对照组(74.51%),组间比较差异具有统计学意义(χ^2=8.54,P=0.00);观察组患者治疗4周后MASI评分为(10.63±3.63)分,略低于对照组的(11.38±3.76)分,组间比较差异无统计学意义(P>0.05);观察组患者治疗后8周、12周MASI评分为(8.21±3.28)分、(6.32±3.51)分,均明显低于对照组的(9.56±3.54)分、(8.23±3.40)分,组间比较差异具有统计学意义(P<0.05);观察组患者不良反应发生率12.31%,低于对照组的27.45%,组间比较差异无统计学意义(P>0.05);观察组患者复发率3.08%,明显低于对照组的13.73%,组间比较差异具有统计学意义(P<0.05)。结论:相比单一使用Q开关Nd:YAG 1 064nm激光治疗方案,联合使用氨甲环酸片治疗黄褐斑有效性更明显,可相对减少治疗相关不良反应,且明显降低复发率,可在临床推广使用。     

An Accuracy Comparison of Minimally Invasive Transclavicular‐Transcortical Drilling with Free‐Hand,C‐Shape and Assembly‐Type Guide Device: An In Vitro Study

ObjectivesEnsuring the accuracy of transclavicular‐transcoracoid drilling in the anatomical reconstruction of the coracoclavicular ligament complex with minimally invasive incisions remains a major problem for inexperienced surgeons. The purpose of this study was to design an assembly guide device for transclavicular‐transcoracoid drilling with minimally invasive incisions, to manufacture the finished product, and to compare its feasibility and accuracy with the existing C‐shape guide devices and free‐hand techniques.MethodsAn assembly‐type guide device was designed and produced using computer‐aided design and three‐dimensional printing. The specimen data of 54 human shoulders from 27 gross specimen (14 males and 13 females) treated by free‐hand drilling, C‐shape device drilling, and assembly‐type guide device drilling from October 2018 to January 2021 were analyzed in a controlled laboratory study. Fifty‐four human shoulder specimens were randomly assigned into free‐hand (n = 18), C‐shape (n = 18), and assembly (n = 18) groups by drawing lots for transclavicular‐transcoracoid drilling by three inexperienced surgeons. After the drilling procedure was completed and the devices were removed, the operation outcomes were assessed and evaluated. Distances from the tunnel edge to the coracoid''s medial (d _m) and lateral (d _l) edges, operation time, and tunnel location zones on the coracoid''s inferior surface of all specimens in the three groups were measured to evaluate the surgical accuracy and efficiency.ResultsAll specimens in the three groups completed the drilling operation successfully and were correctly measured. The distance differences (d _d) between d _m and d _l in the free‐hand, C‐shape, and assembly groups were 3.2 ± 1.8 mm, 1.8 ± 1.0 mm, 1.0 ± 0.8 mm, respectively. The d _d of the free‐hand group was higher than that of the other two groups (p < 0.001). The tunnel exit points on the inferior coracoid surface located in undesired zones were six (33%), one (6%), and zero in the free‐hand group, C‐shape group, and assembly‐type group, respectively (p = 0.012). The operation time in the free‐hand, C‐shape, and assembly groups were 198 ± 36 s, 256 ± 64 s, and 353 ± 88 s, respectively. The operation time of each group significantly differed from that of the others (p < 0.001).ConclusionThe assembly‐type devices may be the first choice for inexperienced surgeons while both the C shape devices and assembly‐type guide devices achieved higher accuracy than free‐hand techniques.