Image Intensifier Research Articles

Pathomorphological characteristics of cotyledons with weak contrasting of the blood flow in the placenta of women who have undergone exacerbation of cytomegalovirus infection during the second trimester of pregnancy

Aim. To give pathomorphological characteristics of placental cotyledons with weakly contrasted bloodstream in women who had an exacerbation of cytomegalovirus infection (CMVI) in the second trimester of pregnancy.Materials and methods. A study was made of involutive-destructive processes in 153 cotyledons of the placenta with well and weakly contrasted bloodstream in women with pregnancy, uncomplicated and complicated by exacerbation of CMVI at 21-24 weeks of gestation. The first group included 36 cotyledon placentas from women with CMV-seronegative uncomplicated pregnancy with well contrasted blood vessels; the second group – 67 cotyledon placentas from patients with chronic compensated placental insufficiency (CCPI) and poorly contrasted vascular network; the third group – 30 cotyledon placentas from women with chronic subcompensated placental insufficiency (CSPI) with indistinctly visualized blood vessels; the fourth group – 20 cotyledon placentas from patients with chronic decompensated placental insufficiency (CDPI). Dosed introduction of red lead on drying oil (1:3) into the blood vessels of the placenta was carried out through the umbilical cord vein. Obtaining X-ray images of cotyledons with well and weakly contrasted blood vessels in the marginal part of the organ was carried out on the apparatus RUM-20M with X-ray image intensifier Sapphire (Russia). Cotyledon biopsy specimens for histometry and histochemical analysis were taken before their contrasting, and for survey microscopy – after injection of the contrast mass.Results. In the first group, the amount of fibrinoid in the stroma of the villi was 1.35±0.09%, perivillous fibrinoid − 1.02±0.08% in the absence of pseudonecrosis and calcifications. In the second group, unlike the first one, cotyledons prevailed, in which in 40-50% of cases weakly expressed contours of blood vessels were found, an increase in the specific volume of stromal fibrinoid by 1.82 times was observed (p<0.001), and fibrinoid around villi by 2.04 times (p<0.001); pseudonecrosis accounted for 2.29±0.13%, and calcificates − 1.50±0.12%. In the third group, in comparison with the second one, cotyledons were more common with 50-70% of indistinctly contoured vessels, villi with edematous changes and stromal collagenization; the concentration of stromal fibrinoid increased by 1.47 times (p<0.001), the proportion of perivillous fibrinoid – 1.46 times (p<0.001), pseudonecrosis – 1.41 times (p<0.001) and the accumulation of calcium salt – 1.57 times (p<0.001). In the fourth group, compared to the third one, cotyledons were more common, in which more than 70% of weakly contrasted blood vessels were determined, while the number of collagen fibers and acid glycosaminoglycans increased in the villi; there was an increase in the amount of fibrinoid around the villi by 1.24 times (p<0.01), pseudonecrosis – by 1.23 times (p<0.05) and calcificates – by 1.32 times (p<0.01).Conclusion. In women with an exacerbation of CMVI in the second trimester of gestation and CSPI, in contrast to patients with a similar infectious disease and CCPI, a decrease in the flow of contrast into the bloodstream of cotyledons is due to more pronounced edema, the formation of collagen fibers, fibrinoid and calcium salts in the stroma of the villi, as well as perivillous fibrinoid. In CDPI of cytomegalovirus etiology, compared with CSPI, weak contrasting of the vascular bed of cotyledons is associated with increasing changes in the stroma involved in the regulation of the resistance of draining veins and intracotyledon blood vessels.

Gas puff imaging system for edge plasma fluctuation measurements in large helical device.

A gas puff imaging system has been developed to measure edge fluctuations in large helical device. The optical system splits the image of the plasma into four wavelengths, Hα/Dα (656nm), HeI (1s2p-1s3d; 587.6; 1s2p-1s3d, 667.8; and 1s2p-1s3s, 706.5nm), enabling simultaneous measurement of the spatial distribution of line ratios of He I. The image of the plasma is amplified with an image intensifier and recorded with a fast-framing camera. The measurement area has a diameter of 20cm just outside of the last closed flux surface. The spatial resolution of the optical system is about 3mm, and the frame rate is 100kHz for acquisition of the four wavelength images. Signal-to-noise ratio is evaluated for the system, and further improvement is discussed. Clear images are obtained for all wavelengths and a slightly different pattern is recognized, depending on the wavelength. A singular value decomposition analysis can decompose the image clearly to one perpendicular and parallel to the magnetic field lines.

Arthroscopic-Assisted Coracoclavicular Stabilization With Anchorless Transosseous Double-Row Acromioclavicular Ligament Complex Repair: The Acute Acromioclavicular Joint Dislocation

The current concept procedures in the acute acromioclavicular joint dislocation should be divided into 2 types of structure restoration: those that provide coracoclavicular stabilization, which affects the primary healing of the coracoclavicular ligaments by vertically stabilizing the clavicle and coracoid in their anatomical positions, and those that attempt to repair the superior acromioclavicular ligament complex, which controls both horizontal and rotational stabilization. The acute acromioclavicular joint dislocation clinical outcome will be achieved if you perform both procedures. It’s difficult to stabilize the acromioclavicular joint in both vertical and horizontal planes, and most current techniques aren't always effective. In this Technical Note, we discuss an arthroscopic-assisted technique that reconstructs the coracoclavicular and acromioclavicular ligaments under image intensifier guidance to achieve bidirectional (vertical and horizontal) and rotational stability.

Magneto-acoustic-electrical tomography combining maximum length sequence-coded excitation and liquid metal image contrast agent.

Magneto-acoustic-electrical tomography (MAET) combines the advantages of ultrasound and electrical impedance functional tomography methods and has important research value in the early diagnosis of tumors and biocurrent monitoring. In this study, we propose a MAET method combining liquid metal image enhancement and maximum length sequence (MLS)-coded excitation to improve the signal-to-noise ratio (SNR) of MAET. The results indicate that liquid metal can achieve image enhancement of tissue MAET. When 7-, 15-, 31- and 63-bit MLS-coded excitations were applied to the samples, the SNR was improved by 28, 34, 40 and 45 dB, respectively. For a similar SNR improvement, the total used time under 31-bit MLS-coded excitation can be shortened to 23% under single-pulse excitation. The experimental results prove the feasibility of applying the MLS code to rotational MAET and reveal the significance of liquid metal as an image intensifier to improve the quality of MAET.

Oral 1 - Trans-Perineal Image Intensifier Guided Biopsy of the Prostate in Patients with Previous Proctectomy- A Novel Technique

Oral 1 - Trans-Perineal Image Intensifier Guided Biopsy of the Prostate in Patients with Previous Proctectomy- A Novel Technique

Attitudes and practices of orthopedic surgeons when using fluoroscopy in the operating room

Introduction: The aim of this study is to assess the practices and knowledge levels of Moroccan orthopedic surgeons on the possible uses and risks of fluoroscopy and to evaluate methods for preventing radiation damage in the operating room. Methods: A questionnaire with a total of 16 questions was sent by courier to 180 Moroccan orthopedic surgeons and orthopedic resident physicians practicing in Morocco. The questionnaire assessed participants' knowledge of the uses and risks of fluoroscopy and methods of preventing harm. The effects of fluoroscopy on patients were not evaluated in our study. Results: The data obtained were statistically evaluated. Of the surgeons surveyed 53.3% were medical specialists, 29.4% were resident doctors and 17.2% were professors. The number of people with more than ten years of experience was 48.9%, only 6.1% of participants had less than one year of experience. 61.1% of surgeons used fluoroscopy between 2 to 5 times per week, almost 8% of participants used the image intensifier more than 10 times per week. Among the surgeons surveyed, 87.2% had never received training on the principles of using fluoroscopy. Dosimeters were not used by 95% of the surgeons surveyed. Conclusion: According to the survey results, the need for fluoroscopy was very high in orthopedic surgery. However, orthopedic surgeons have inadequate knowledge about the uses and risks of fluoroscopy and methods for preventing damage. Therefore, we believe that training on this topic should be provided to all orthopedic surgeons.

A Small Step to Improve Tibial Alignment in Knee Replacement

Introduction: Though total Knee replacement has proved to be a rewarding surgery for patients with end stage knee arthritis, errors in surgical technique leading to malalignment of components can lead to early failure. The aim of this study was to increase the accuracy in identifying the centre of ankle joint which is the first step in achieving a proper tibial cut for a well placed tibial implant. Technique: We propose a simple, reproducible technique to locate centre of ankle under image intensifier. Results: The above technique was used in 30 patients who were operated by two surgeons during a period of 6 months from January 2022 to June 2022. Post-op measurements of the alignment of tibial implant were done electronically on computer and physically on X-rays. 21 of the 30 cases (70%) had good placement of the implant within 1 degree of ideal alignment and 9 (30%) within 2 degrees. Discussion: A correct proximal tibia cut for a well aligned tibial component is achieved with the help of precise application of the cutting jigs. Extramedulalry jigs used to make the proximal tibia cut have to be aligned parallel to the axis of the tibia and centred over the midpoint of talus. Several methods have been proposed by various authors to locate centre of the ankle joint. However, at present there is no consensus on the best method. Even computer navigation relies on accurate feeding of anatomical reference points which is done manually. Conclusion: Our technique is precise, accurate, repeatable, objective and less time consuming. It adds value to achieving the final aim of a good implant position. The technique has a dual advantage as it gives a better estimate of not only the centre of the ankle but also the centre of the distal tibial mechanical axis.

Experimental study of turbulent flame propagation under wall film conditions

The presence of a liquid wall film caused by spray impingement is inevitable in modern direct injection engines and can have a substantial effect on flame dynamics and pollutant emissions. The present study investigated the effects of a wall film on turbulent flame propagation characteristics under different initial conditions. In these trials, methane-air premixed turbulent jet flames were established in a constant volume vessel with a small pre-chamber connecting to the main chamber through a narrow orifice. Various fuel films were prepared on the surface of a side plate installed in the main chamber. The flame morphologies were captured using a high-speed schlieren photographic system and the intensity of pool fire was examined by an image intensifier with UV lens. Meanwhile, temporal pressures in both chambers were recorded by two pressure sensors respectively. Changes in turbulent combustion phases in conjunction with single and multi-component wall films were analyzed based on flame propagation features, pressure data and film pyrolysis characteristics over ranges of equivalence ratios (0.8–1.2) and initial pressures (0.2–0.4 MPa). Gas phase emissions were also evaluated to further explore the effects of wall films on turbulent combustion. The high reactivity of the fuel films was found to increase the turbulent flame speed and provide higher peak pressures, although the heat absorbed by evaporation delayed the pressure rise time. The volatility of the film material affected the propagation speed together with the jet flame area growth and these effects were more obvious under lean combustion conditions. Film pyrolysis was triggered as multiple turbulent flows converged near the film region and produced a pool fire with soot deposition. The peaks of pressure and pressure rise rate observed when using a diesel film were intermediate between those obtained with n-dodecane and n-tetradecane films. A lubricating oil film pool fire also appeared after increasing the initial pressure but its intensity was weaker than those of the fires generated by the fuel films.

Modified Posterior 2-Portal Technique of Arthroscopic Subtalar Joint Arthrodesis: Improved Pain and Functional Outcome at Mean 15Months Follow-up-A Case Series.

Posterior arthroscopic subtalar joint arthrodesis (PASTA) via a posterior 2-portal technique has been described. We modified the surgical technique of creating the portals in the plane of the posterior facet (under fluoroscopy guidance) to enhance the ease of access to the joint, easier and complete removal of articular cartilage along with maintaining the heel height. Patients of post-traumatic subtalar joint arthritis, treated by PASTA during 2016 till 2019 were included in the study. Exclusion criteria: significant height collapse of calcaneum, lateral blow out or heel widening. The confirmation of subtalar joint as the source of pain was done by injection of local anaesthetic inside the joint under the image intensifier, bringing immediate pain relief. The primary outcome variables assessed were the pain and functional scores, assessed using visual analogue scale and AOFAS (American Orthopaedic Foot and Ankle Society) score, respectively. The total of 16 patients (7 males, 9 females) was included. The average age was 40.68years (23-58years). The underlying pathology in all patients was post-traumatic subtalar arthritis secondary to calcaneus fracture malunion in 8 patients (50%), talus fracture malunion in 4 (25%) and ligament injury in 2 patients (12.5%). No bone grafting was done. The mean duration of follow-up was 15.6months (9-24months). There was a statistically significant improvement (p < 0.001) in mean VAS score at follow up (2; range 0-4) as compared to the mean preoperative score (7; range 6-9). The AOFAS score also improved significantly (p < 0.001) at the follow up (mean 79; range 68-89) as compared to the preoperative score (mean 18; range 10-25). The posterior arthroscopic fusion of subtalar joint gives good results in terms of pain relief and functional scores when done for carefully selected patients of subtalar joint arthritis. Our slight modification of the original technique improves the ease of removing cartilage from subtalar joint with minimal height loss; thus, precluding any need for bone graft. It also makes the instrument movement easier inside the joint.

Implications of cage impactions in single-level OLIF treatment of degenerative spondylolisthesis

IntroductionCage impactions (CI) of Oblique Lumbar Interbody Fusion (OLIF) appear to be a frequent mechanical complication with a potential functional impact. ObjectivesTo determine the rate of CI occurrence, their risk factors and clinical implications in the case of combined single-level arthrodesis. MethodA retrospective analysis of prospectively collected data was performed. All our patients with degenerative spondylolisthesis initially underwent OLIF combined with pedicle screw fixation (PSF). Intraoperative control with an image intensifier and a standard radiograph in the immediate postoperative period made it possible to assess the occurrence of CI, depending on the position of the implant. Secondary subsidence was sought on the standing radiological examination using EOS biplanar radiography during follow-up. The pelvic parameters were analyzed, as well as the occurrence of bone fusion. The clinical evaluation was made at≥1 year, by the Oswestry Disability Index (ODI), the walking distance (WD) and the Visual Analogue Scale (VAS). ResultsIn all, 130 patients out of the 131 included were analyzed. A CI occurred in 25.3% (n=33) of cases and of these, 94% (n=32) occurred intraoperatively. Postmenopausal women had more CI with an odds ratio (OR) of 5.8 (P=0.034). The “CI” group had a 9.5% lower ODI score than the “non-CI” group (P=0.0040), but both provided excellent ODI gains of 30.8±16 and 32.9±15.5% (P<0.0001). An “anterior” position of the implant allowed a greater gain in lumbar lordosis (P<0.001) but was associated with greater CI occurrence (P<0.001), with an OR of 6.75 (P=0.0018). ConclusionThe occurrence of intraoperative cage impaction is a frequent event when performing OLIF. Postmenopausal women have an approximately 6 times greater risk of impaction than men, and patients with an “anterior” implant placement have a 7 times greater risk than with central placement. The negative impact of cage impactions on the clinical score (ODI) was significant after one year of follow-up. Level of evidenceIV, non-comparative cohort study.

Fast phase differentiation between liquid–water and ice by pulsed neutron imaging with gated image intensifier

This paper reports on development of pulsed neutron imaging for phase differentiation between liquid–water and ice with introduction of a gated image intensifier. Automotive fuel cells must be operated in a variety of environments, including subzero start-up operations. The precise distribution of liquid–water and/or ice in the fuel cell is critical because gas obstruction by ice has a significant impact on power generation efficiency. While various probes such as electrons, visible light, infrared light, X-ray, and neutron have been used to observe the behavior of H2O in polymer electrolyte fuel cells (PEFCs) under subzero temperatures, neutron imaging is one of the most powerful methods to distinguish ice from liquid–water in the metal cells nondestructively. Previous neutron-imaging systems for phase differentiation between liquid–water and ice, on the other hand, had some issues with temporal resolution, horizontal distribution of neutron wavelength, and field-of-view size. By using energy-selected pulsed neutron imaging with an optical image intensifier, the authors have achieved liquid–water/ice phase identification with a shorter temporal resolution than before with 280 × 280 mm 2, which is roughly the size of commercial PEFCs, and 86 × 86 mm 2 fields of view. The horizontal distribution of neutron wavelength was also sufficiently suppressed.

100 megahertz-rate ultrahigh-speed digital holography instrument

This work presents the development of an ultrahigh-speed digital holography instrument that can perform volumetric measurements at a rate of up to 100 million frames per second. The system is based on an Ultra 8 camera that uses a single custom-built image intensifier with a segmented photocathode that can gate eight different imaging regions down to 10 ns. An in-line interferometric scheme is used to capture the deformation of a water drop as it is photoablated from irradiation by a 1064 nm wavelength pulsed laser beam. After a digital holographic video is captured, wavefront reconstruction is used to focus on discrete depth planes enabling the user to observe different 3-dimensional features of the drop as the field-of-view is scanned plane-by-plane. The reconstructions are detwinned and corrected for parallax and alignment error before a final image at any given depth is produced. We provide one-to-one comparisons between conventional focused imaging and digital holography to demonstrate the 3-dimensional visualization capabilities of the instrument with particular regard to dynamic events occurring at nanosecond time intervals for future applications to hypersonic flows and other short and ultrashort duration events.

Intraoperative Comparative Femoral Rotation Imaging: Do not Overlook Parallax.

To investigate the degree of error due to parallax during intraoperative rotational imaging involving the distal femur. Twelve, fresh-frozen, lower-extremity cadaveric specimens were studied. The limbs were positioned supine and rotated until the posterior femoral condyles were superimposed using a C-arm. The C-arm was then repositioned to place the femoral condyles at the anterior and posterior margins of the image intensifier. The rotation necessary to resuperimpose the femoral condyles due to parallax was recorded. A second C-arm was then used from the contralateral side to simulate the rotational imaging technique to determine the magnitude and directionality of combined parallax. All 12 specimens demonstrated parallax, resulting in rotational discrepancies. Compared with central field of view alignment, the mean rotational discrepancy was 5.6 and 5.5 degrees for anterior and posterior positions, respectively. Contralateral imaging resulted in an additive effect with rotational differences of 9.0 and 12.6 degrees for bilateral anterior and posterior positions, respectively. Parallax causes rotational discrepancies with fluoroscopic imaging of the distal femur when the posterior femoral condyles are off-center in the imaging field of view. If femoral condyles are not centered when obtaining intraoperative rotational imaging of the uninjured and injured femurs, parallax can result in potentially clinically significant rotational deformity even if the femurs seem perfectly matched at the conclusion of surgery. We recommend perfectly centering of the posterior femoral condyles in the imaging field of view when obtaining lateral images of the distal femur to prevent this potentially overlooked contribution to malrotation.

Outcomes after primary intramedullary nail fixation of open tibial and femoral fractures in low resource settings.

Open fractures are unique in the urgency they impart to the injury and the therapeutic challenge they pose. Non-union and infection are among the major concerns. Open tibial and femoral shaft fractures are among the commonest orthopaedic urgencies. Primary intramedullary (IM) nailing requires a skillset and knowledge of the principles of open fracture management and also a well-equipped operating room with the necessary implants and instruments. In a low resource setting, one or more of these prerequisites may not be met, and the outcome may thus be affected similarly. The objective of this study was to study these outcomes. We prospectively studied primary IM nailing of open 1, 2 and 3A tibial and femoral fractures done in our hospital, in a simple non-modular operating room without an image intensifier. There were 106 fractures in 104 patients: 93 tibial and 13 femoral. The mean time from injury to surgical debridement was 19.6h. Mean duration of antibiotics therapy was 4.3days, and the mean duration of hospital stay was 4.1days. All patients were followed up to union. Mean time to radiographic union was 6.1months for the tibia and 5.7months for the femur. Non-union was seen in 4 tibial and 1 femoral fractures. There were 3 superficial infections but no deep infection. The outcomes were comparable to, and in some cases better than, those found in existing literature. We conclude that primary IM nailing in open long bone fractures can be performed in austere environments with good success, in expert hands if the principles are adhered to.

TREATMENT INTERTROCHANTERIC FRACTURE OF FEMUR IN ELDERLY BY EXTERNAL FIXATION: PROSPECTIVE CASE-SERIES STUDY; IBN-SINA TRAINING HOSPITAL, BAGHDAD

Background: Internal fixation is gold standard in treatment of intertrochanteric fractures, but in patients with anesthesia or surgical hazards the external fixation should be explored as a safe approach to reduce operative time and complications risk. Objective: To assess the outcome of external fixation of an intertrochanteric fracture is in elderly patients with co-morbidities. Methods: Twenty-eight elderly patients with non-pathological fractures, closed, who were 65 years old or older, unsuited for surgery for a long period, and had chronic uncontrolled medical problems such as hypertension, diabetes mellitus, or heart disease were included in the study. Criteria for exclusion include reverse obliquity fractures, dementia, pathological fractures and prior hip fractures. Those patients treated with percutaneous external fixation under image intensifier from 2015 to 2020 in Ibn Sina Training Hospital in Baghdad. Results: At 1-year follow-up, 80% returned to pre-fracture ambulatory status. Average time to fixator removal was 12 weeks. There were no cases of pin loosening, breakage, or penetration of femoral head. All patients were evaluated clinically and radiologically for 24 months except 3 patients, 2 died 6 months’ post-operative due to causes unrelated to the surgery, and 1 lost follow up 3 months after surgery. Excellent and good results were found in 8 patients. The time of radiological union and fixator removal about 12 weeks. Pin tract infection occurred in most of the patients. Varus malalignment occurred in 20% of patients. Shortening ranged from 0 to 3 cm. Conclusion: External fixation of intertrochanteric fractures in elderly high-risk patients is a dependable, successful, and safe therapeutic option. Keywords: Intertrochanteric fracture, external fixator, elderly patient Citation: Alsudany FKI, Alhamashi AHS, Al-Abbody HHT, Ismael HA. Treatment intertrochanteric fracture of femur in elderly by external fixation: prospective case-series study; Ibn-Sina Training Hospital, Baghdad. Iraqi JMS. 2022; 20(1): 113-120. doi: 10.22578/IJMS.20.1.15

An Analysis of 50 Consecutive Total Ankle Replacements Undergoing Preoperative Computerized Tomography Scan-Based, Engineer-Provided Planning From a Single Noninventor, Nonconsultant Surgeon

Preoperative computerized tomography (CT) scan-based, engineer-provided alignment plans and patient-specific pinning blocks for total ankle replacement (TAR) are available for use in the United States. However, nonbiased studies that justify the additional expense associated with this technology through support of the marketed benefits of less procedural complexity, less intraoperative radiation and reduced surgical time, are lacking. Therefore, to verify the manufacturer's proposed benefits, we sought to investigate our experience with this preoperative CT scan-based, engineer-provided plan and patient-specific pinning blocks during primary TAR. In review of our 50 TAR patients, we found that “perfect” radiographic alignment was not consistently achieved and the accuracy of component prediction was modest. Furthermore, the preoperative plans and patient-specific pinning blocks did not simplify the complexity of our operations since the operative time, intraoperative image intensification time and radiation dose per case all exceeded published historical TAR controls. Interestingly, we identified a significant difference in placement accuracy between the arced and flat-top talar component types that were implanted with the arced being more frequently malaligned. We did not find associations between preoperative deformity severity and accuracy of postoperative alignment. These findings suggest that it is imperative to have surgeons continue to rely on their own surgical planning and experience to achieve optimum radiographic alignment rather than depending on engineer-based recommendations or “surface matched” pinning blocks. Ultimately, we were unable to support the purported benefits of this CT scan-based, engineer-provided alignment plan and patient-specific pinning blocks for this manufacturer's primary TAR systems.

Comparative analysis of the effectiveness of the combined method of inserting pedicle screws with the free-hand technique in patients with idiopathic scoliosis

Objective. To analyze intraoperative data and results of treatment of patients with idiopathic scoliosis with two options of the open insertion of pedicle screws using the free-hand technique.Material and Methods. The data of 457 patients aged 16–35 years who underwent surgical treatment for idiopathic scoliosis by one surgeon were analyzed. In 236 patients (Group I), the screws were placed manually, and in 221 (Group II) – using power tool. The preparation of the canal for pedicle screws in both groups was performed using the free-hand technique. The correct position of the screws wasassessed intraoperatively using an image intensifier and neurophysiological monitoring. The duration of surgery and X-ray monitoring, blood loss, and the presence of intra- and postoperative complications were assessed.Results. In Group I, 4243 screws were inserted, and in Group II – 3978. The correct position of pedicle screws was recorded in 89.1 % of cases in Group I, and in 89.6 % of cases in Goup II. In Group I, the incorrect position of anchor elements was detected in 10.9 % of cases, and in Group II – in 10.4 % of cases. The number of screws re-positioned intraoperatively corresponded to the number of incorrectly positioned screws. There was a statistically significant difference in the volume of intraoperative blood loss and duration of surgery betweenpatients of both groups (p &lt; 0.05).Conclusion. The development and active introduction of high-tech methods of surgical treatment of spinal deformities increase the number of interventions performed annually. The proposed combined method of surgical treatment seems to be optimal because manual formation of the canal reduces the risk of intraoperative complications, and the use of power tool during screw placement shortens duration of surgery and reduces blood loss.

Volar locking plate fixation for distal radius fractures: did variable-angle plates make difference?

PurposeTwo different locking plate designs are now being used for volar plating of the distal radius fractures based on the freedom of screw direction; the fixed-angle, and the variable-angle (polyaxial) plates. We investigated the clinical and radiographic outcomes of both designs.MethodsWe reviewed 96 patients with 113 unstable distal radius fractures that were operated on with volar locking plates. The patients’ mean age was 41 years. Fixed-angle volar locking plates were utilized in 65 fractures and variable-angle volar locking plates in 48 fractures through modified Henry approach or extended carpal tunnel approach. Full clinical and radiographic evaluation was done for all patients with a mean follow-up of 14 months.ResultsAll patients had acceptable clinical and radiographic parameters. The overall functional results (Mayo score, Quick Disability of Arm, Shoulder, and Hand (Q-DASH) score, Range of motion (ROM), and grip strength) were in favor of the variable-angle plate. The radiographic parameters were better with the variable-angle group. The variable-angle group recorded less operative time but more mean image intensifier exposure time. There were two cases of flexor tendon rupture with the fixed-angle group. Fixation with the fixed-angle system needed K-wire augmentation more than the variable-angle group. There was a positive correlation between hand dominance and the final score.ConclusionDistal radius volar locking plates yield satisfactory results comparable among different designs. In our series, the variable-angle system showed slightly better function and radiographic outcomes. Supplementary K-wires were needed more frequently with the fixed-angle system.

Objective evaluation of integrated structural defects of low-light-level image intensifier based on local image patch extreme and frequency fast Fourier transform

Integrated structural defects are one of the most common defects in the microchannel plate fabrication and physicochemical treatment stage of low-light-level (LLL) image intensifiers. Its appearance seriously affects the imaging quality. The traditional evaluation method of such defects is solely based on visual observation, and its main disadvantages are strong subjectivity and large uncertainty. To address the above problems, two objective evaluation methods of integrated structural defects of an LLL image intensifier are introduced. The first is based on local image patch extreme, and the second is based on frequency fast Fourier transform. The basic idea of the first method is to scan the effective area (EA) of the target image globally and then extract the target defect by adopting a series of local image patch extremes adjacent in the Y-axis. Experimental results reveal that this method shows excellent performance in detecting and positioning accuracy while the time cost is satisfactory. The general steps of the second method are to scan the EA globally, and then perform a fast Fourier transform on the obtained image patch; through bandpass filtering in the frequency domain and inverse Fourier transforming the convoluted image, structures or objects projecting the similar characteristics of integrated structural defects are detected. This method not only maintains good detection integrity but also ensures high detection accuracy. Through experiments on several defective image intensifiers and compared with traditional relevant technologies, we conclude that the proposed methods can realize the high-precision objective detection of integrated structural defects of LLL image intensifiers and can be used as effective alternatives to the traditional evaluation method of such defects.

Adsorption of residual gas on the (001) surface of Cs/O co-sensitized In0.53Ga0.47As photocathode

For near-infrared low-light image intensifiers, the low quantum efficiency of the photocathode is often a critical cause limiting its widespread use. Of these, the damage caused by residual gas molecules attached to the cathode surface during the sensitization process is most likely to be blamed. Herein, using the first-principles calculation method, we inspected the behavior of different gas molecules adhering on the sensitized In0.53Ga0.47As photocathode surface. Particular emphasis is placed on changes in surface stability and electronic properties. The detailed calculation results show that the adhering of gas molecules significantly destroy the original atomic stability of the cathode surface. In addition, a new dipole named [Cs-Gas] is formed, which greatly damages the surface electronic properties, especially increasing the surface work function and electron affinity. Besides, we also compared the diverse performances of residual gas molecules adsorption on two different systems (only-Cs and Cs/O sensitized surface). Our investigations are dedicated to further revealing the effect of residual gas molecules adsorption on the photoelectric properties of Cs/O co-sensitized In0.53Ga0.47As (001) surface.