Motec Wrist Arthroplasty: 4 Years of Promising Results

BACKGROUND

The Motec cementless modular metal-on-metal ball-and-socket wrist arthroplasty is an implant with promising intermediate results. An alternative to primary wrist fusion, total wrist arthroplasty is an option for active patients, who wish to retain their wrist function. It is indicated in cases of degenerative osteoarthritis, post-traumatic arthritis and rheumatoid (inflammatory) arthritis.

METHODS

A prospective review of patient demographics, pre and post-operative Disabilities of the Arm Shoulder and Hand (DASH), MAYO scores, range of movements and grip strengths. All complications in follow up were recorded across the 4 year period.

RESULTS

25 implants on 23 patients over 5.5 years, mean age 61; 8 females and 15 male. 10 patients with SLAC, 3 SNAC, 5 inflammatory and 7 patients with generalized osteoarthritis. The patients showed significant improvements of MAYO and DASH scores post-operatively, as well as the flexion/extension arc and grip strengths. There was just one case of implant loosening- the radial screw after a wound infection, which was revised with a longer screw. Two implants were converted to Motec fusion due to pain. One implant was dislocated and relocated. The remaining patients have had good wrist function. Only 6 patients were unable to return to work.

CONCLUSIONS

Similar to published studies, this series shows the Motec implant to be a good motion preserving alternative to total wrist fusion.

Rudiment resorption as a response to starvation during larval development in the sea urchin Strongylocentrotus droebachiensis

Phenotypic flexibility (reversible phenotypic change) enables organisms to couple internal, ontogenetic responses with external, environmental cues. Phenotypic flexibility also provides organisms with the capacity to buffer stereotypical internal, developmental processes from unpredictable external, ecological events. Echinoids exhibit dramatic phenotypic flexibility in response to variation in exogenous nutrient supplies. The extent to which echinoids display this flexibility has been explored incompletely and research hitherto has been conducted predominantly on larval structures and morphologies. We investigated experimentally the extent to which the primordial juvenile, the developing rudiment, can exhibit the first phase in phenotypic flexibility among individuals. We report for the first time on rudiment regression and complete resorption as a response to starvation during larval development in the sea urchin Strongylocentrotus droebachiensis (O.F. Müller, 1776) and identify a developmental “window of opportunity” within which this can occur. Based on our observations and previous suggestions, we speculate that sea urchin rudiments might provide means of buffering development during unfavorable conditions.

Use of material decomposition in the context of neurovascular intervention using standard flat panel and a high-resolution CMOS detector

The imaging of endovascular devices during neurovascular procedures such as the coiling of aneurysms guided with CBCT imaging may be challenging due to the presence of highly attenuating materials such as platinum in the coil and stent marker, nickel-titanium in the stent, iodine in the contrast agent, and tantalum in the embolization agent. The use of dual-energy imaging followed by a basis material decomposition image processing-scheme may improve the feature separation and recognition. Two sets of testing were performed to validate this concept. The first trial was the acquisition of dual-energy micro-CBCT data of a 3D-printed simple aneurysm model using a 49.5 μm pixel size CMOS detector (Teledyne DALSA, Waterloo, ON.). Two sets of projection data were acquired using beam energies of 35 kVp and 70 kVp. Axial slices were reconstructed and used to carry out the material decomposition processing. The second trial was the acquisition of dual-energy CBCT images of a RS-240T angiographic head phantom (Radiology Support Devices Inc., CA.) with an iodine vascular insert using a Toshiba Infinix BiPlane C-arm system coupled to a flat panel detector. Two sets of image data were acquired using beam energies of 80 kVp and 120 kVp. Following image reconstruction, slices of the phantom were decomposed using the same processing as previously. The resulting image data over both trials indicate that the decomposition process was successful in separating the kinds of materials commonly used during a neurovascular intervention, such as platinum, cobalt-chromium, and iodine. The normalized root mean square error metric was used to quantitatively assess this. This indicates a basis for future more clinically relevant testing of our methods.

Evaluation of 4-methyl-2-[(2-methylbenzyl) amino]-1,3-thiazole-5-carboxylic acid against hyperglycemia, insulin sensitivity, and oxidative stress-induced inflammatory responses and β-cell damage in the pancreas of streptozotocin-induced diabetic rats

4-Methyl-2-[(2-methylbenzyl) amino]-1,3-thiazole-5-carboxylic acid (bioactive compound (BAC)), a novel thiazole derivative, is a xanthine oxidase inhibitor and free radical scavenging agent. Effects of BAC on hyperglycemia, insulin sensitivity, oxidative stress, and inflammatory mediators were evaluated in streptozotocin (STZ)-induced neonatal models of non-insulin-dependent diabetes mellitus (NIDDM) rats where NIDDM was induced in neonatal pups with single intraperitoneal injection of STZ (100 mg/kg). The effect of BAC (10 and 20 mg/kg, p.o.) for 3 weeks was evaluated by the determination of blood glucose, oral glucose tolerance test (OGTT), HbA1c level, insulin level, insulin sensitivity, and insulin resistance (IR). Furthermore, inflammatory mediators (tumor necrosis factor-alpha and interleukin-6) and oxidative stress were estimated in serum and pancreatic tissue, respectively. Significant alteration in the level of blood glucose, OGTT, HbA1c, insulin level, insulin sensitivity, in addition variation in the antioxidant status and inflammatory mediators, and alteration in histoarchitecture of pancreatic tissue confirmed the potential of BAC in STZ-induced neonatal models of NIDDM rats. Pretreatment with BAC restored the level of glucose by decreasing the IR and increasing the insulin sensitivity. Furthermore, BAC balanced the antioxidant status and preserved the inflammatory mediators. Histological studies of pancreatic tissues showed normal architecture after BAC administration to diabetic rats. Altogether, our results suggest that BAC successfully reduces the blood glucose level and possesses antioxidant as well as anti-inflammatory activities. This leads to decreased histological damage in diabetic pancreatic tissues, suggesting the possibility of future diabetes treatments.

Differences in Morphologic and Hemodynamic Characteristics for "PHASES-Based" Intracranial Aneurysm Locations

BACKGROUND AND PURPOSE

Several recent prospective studies have found that unruptured intracranial aneurysms at various anatomic locations have different propensities for future rupture. This study aims to uncover the lack of understanding regarding rupture-prone characteristics, such as morphology and hemodynamic factors, associated with different intracranial aneurysm location.

MATERIALS AND METHODS

We investigated the characteristics of 311 unruptured aneurysms at our center. Based on the PHASES study, we separated and compared morphologic and hemodynamic characteristics among 3 aneurysm location groups: 1) internal carotid artery; 2) middle cerebral artery; and 3) anterior communicating, posterior communicating, and posterior circulation arteries.

RESULTS

A mixed model statistical analysis showed that size ratio, low wall shear stress area, and pressure loss coefficient were different between the intracranial aneurysm location groups. In addition, a pair-wise comparison showed that ICA aneurysms had lower size ratios, lower wall shear stress areas, and lower pressure loss coefficients compared with MCA aneurysms and compared with the group of anterior communicating, posterior communicating, and posterior circulation aneurysms. There were no statistical differences between MCA aneurysms and the group of anterior communicating, posterior communicating, and posterior circulation aneurysms for morphologic or hemodynamic characteristics.

CONCLUSIONS

ICA aneurysms may be subjected to less rupture-prone morphologic and hemodynamic characteristics compared with other locations, which could explain the decreased rupture propensity of intracranial aneurysms at this location.

Porosity of spacer-filled channels in spiral-wound membrane systems: Quantification methods and impact on hydraulic characterization

The porosity of spacer-filled feed channels influences the hydrodynamics of spiral-wound membrane systems and impacts the overall performance of the system. Therefore, an exact measurement and a detailed understanding of the impact of the feed channel porosity is required to understand and improve the hydrodynamics of spiral-wound membrane systems applied for desalination and wastewater reuse. The objectives of this study were to assess the accuracy of porosity measurement techniques for feed spacers differing in geometry and thickness and the consequences of using an inaccurate method on hydrodynamic predictions, which may affect permeate production. Six techniques were applied to measure the porosity namely, three volumetric techniques based on spacer strand count together with a cuboidal (SC), cylindrical (VCC) and ellipsoidal volume calculation (VCE) and three independent techniques based on volume displacement (VD), weight and density (WD) and computed tomography (CT) scanning. The CT method was introduced as an alternative for the other five already existing and applied methods in practice. Six feed spacers used for the porosity measurement differed in filament thickness, angle between the filaments and mesh-size. The results of the studies showed differences between the porosities, measured by the six methods. The results of the microscopic techniques SC, VCC and VCE deviated significantly from measurements by VD, WD and CT, which showed similar porosity values for all spacer types. Depending on the maximum deviation of the porosity measurement techniques from -6% to +6%, (i) the linear velocity deviations were -5.6% and +6.4% respectively and (ii) the pressure drop deviations were -31% and +43% respectively, illustrating the importance of an accurate porosity measurement. Because of the accuracy and standard deviation, the VD and WD method should be applied for the porosity determination of spacer-filled channels, while the CT method is recommended for numerical modelling purposes. The porosity has a linear relationship with the flow velocity and a superlinear effect on the pressure drop. Accurate porosity data are essential to evaluate feed spacer performance in spiral-wound membrane systems. Porosity of spacer-filled feed channels has a strong impact on membrane performance and biofouling impact.

Lack of Association between Statin Use and Angiographic and Clinical Outcomes after Pipeline Embolization for Intracranial Aneurysms

BACKGROUND AND PURPOSE

Use of statin medications has been demonstrated to improve clinical and angiographic outcomes in patients receiving endovascular stent placement for coronary, peripheral, carotid, and intracranial stenoses. We studied the impact of statin use on long-term angiographic and clinical outcomes after flow-diverter treatment of intracranial aneurysms.

MATERIALS AND METHODS

We performed a post hoc analysis from pooled patient-level datasets from 3 Pipeline Embolization Device studies: the International Retrospective Study of the Pipeline Embolization Device, the Pipeline for Uncoilable or Failed Aneurysms Study, and the Aneurysm Study of Pipeline in an Observational Registry. We analyzed data comparing 2 subgroups: 1) patients on statin medication, and 2) patients not on statin medication at the time of the procedure and follow-up. Angiographic and clinical outcomes were compared by using the χ² test, Fisher exact test, or Wilcoxon rank sum test.

RESULTS

We studied 1092 patients with 1221 aneurysms. At baseline, 226 patients were on statin medications and 866 patients were not on statin medications. The mean length of clinical and angiographic follow-up was 22.1 ± 15.1 months and 28.3 ± 23.7 months, respectively. There were no differences observed in angiographic outcomes at any time point between groups. Rates of complete occlusion were 82.8% (24/29) versus 86.4% (70/81) at 1-year (P = .759) and 93.3% (14/15) versus 95.7% (45/47) at 5-year (P = 1.000) follow-up for statin-versus-nonstatin-use groups, respectively. There were no differences in any complication rates between groups, including major morbidity and neurologic mortality (7.5% versus 7.1%, P = .77).

CONCLUSIONS

Our study found no association between statin use and angiographic or clinical outcomes among patients treated with the Pipeline Embolization Device.

Predicting the impact of feed spacer modification on biofouling by hydraulic characterization and biofouling studies in membrane fouling simulators

Feed spacers are an essential part of spiral-wound reverse osmosis (RO) and nanofiltration (NF) membrane modules. Geometric modification of feed spacers is a potential option to reduce the impact of biofouling on the performance of membrane systems. The objective of this study was to evaluate the biofouling potential of two commercially available reference feed spacers and four modified feed spacers. The spacers were compared on hydraulic characterization and in biofouling studies with membrane fouling simulators (MFSs). The virgin feed spacer was characterized hydraulically by their resistance, measured in terms of feed channel pressure drop, performed by operating MFSs at varying feed water flow rates. Short-term (9 days) biofouling studies were carried out with nutrient dosage to the MFS feed water to accelerate the biofouling rate. Long-term (96 days) biofouling studies were done without nutrient dosage to the MFS feed water. Feed channel pressure drop was monitored and accumulation of active biomass was quantified by adenosine tri phosphate (ATP) determination. The six feed spacers were ranked on pressure drop (hydraulic characterization) and on biofouling impact (biofouling studies). Significantly different trends in hydraulic resistance and biofouling impact for the six feed spacers were observed. The same ranking for biofouling impact on the feed spacers was found for the (i) short-term biofouling study with nutrient dosage and the (ii) long-term biofouling study without nutrient dosage. The ranking for hydraulic resistance for six virgin feed spacers differed significantly from the ranking of the biofouling impact, indicating that hydraulic resistance of clean feed spacers does not predict the hydraulic resistance of biofouled feed spacers. Better geometric design of feed spacers can be a suitable approach to minimize impact of biofouling in spiral wound membrane systems.

Prevalence of hypogonadism in male Type 2 diabetes mellitus patients with and without coronary artery disease

AIM

The present study is carried out to investigate hypogonadism using serum testosterone levels in male Type 2 diabetes mellitus (T2DM) subjects with and without coronary artery disease (CAD).

SUBJECTS AND METHODS

A total of 150 age and body mass index-matched male subjects in the age group of 30-70 years were recruited in three groups; Group A - subjects with normal glucose tolerance, Group B - T2DM subjects without CAD, and Group C - T2DM subjects with CAD (n = 50 each group). Subjects with CAD were diagnosed on the basis of electrocardiogram, treadmill testing, stress echocardiography, or coronary angiography. Total testosterone (TT), free testosterone (FT), bioavailable testosterone, calculated FT and glycemic parameters were measured and compared between all the three study groups. One-way ANOVA followed by post hoc Tukey's test and Pearson's coefficient of correlation tests were used for analysis.

RESULTS

Hypogonadism (TT <3 ng/ml) was observed in 40% (20/50) of subjects in Group C and 32% (16/50) of subjects in Group B as compared to only 14% (7/50) of subjects in Group A (Groups A vs. B; P = 0.055, Groups A vs. C; P = 0.006 and Groups B vs. C; P = 0.53). Group C subjects had significantly lower levels of TT (3.55 ± 1.46 ng/ml vs. 4.73 ± 2.17 ng/ml, P = 0.005), calculated FT (0.062 ± 0.0255 pg/ml vs. 0.0951 ± 0.0508 pg/ml, P ≤ 0.001), and bioavailable testosterone (1.48 ± 0.65 ng/ml vs. 2.18 ± 1.20 ng/ml, P ≤ 0.001) compared to control Group A subjects. There was no significant difference in any of the testosterone parameters between Groups A and B. Furthermore, an overall positive correlation was found between hypogonadism and CAD (r = 0.177, P = 0.030, n = 150).

CONCLUSION

We observed hypogonadism as indicated by low testosterone levels in a significant proportion of male T2DM subjects with CAD.

Replantation of digits: a review of predictive factors for survival

The survival of 75 consecutive digital replantations carried out between 2006 and 2010 at a regional hand centre in the United Kingdom was determined. The patient demographics, mechanism of injury, co-morbid factors, operative and post-operative details were extracted and reviewed from the medical and hand therapy notes. Predictive factors of survival were determined by using univariate and multivariate statistical analysis. The survival rate was 70%. Arterial thrombosis was the leading cause of replant failure, followed by venous congestion. Smoking, level of amputation, number of nerves repaired, warm ischaemia time and timing of replantation were independent predictors of replant survival. However, only warm ischaemia time less than 6 hours and 30 minutes and replantations done within 'office hours' showed significance on multivariate logistic regression. Our study suggests that replantations done in daylight hours, when feasible, with rested staff and a full complement of the theatre team are likely to have better outcomes.

LEVEL OF EVIDENCE

Level IV case series.

Simultaneous urodynamic and anorectal manometry studies in children: insights into the relationship between the lower gastrointestinal and lower urinary tracts

BACKGROUND

Children with urinary incontinence (UI) have associated functional constipation (FC) and fecal incontinence (FI). The physiology between lower urinary tract (LUT) and anorectum in children has not been elucidated.

AIMS

Observe the effect of rectal distention (RD) on LUT function, and bladder filling and voiding on anorectal function.

METHODS

Children with voiding dysfunction referred to Boston Children's Hospital were prospectively enrolled in combined urodynamic (UDS) and anorectal manometry (ARM). Anorectal and urodynamic parameters were simultaneously measured. Patients underwent two micturition cycles, first with rectal balloon deflated and second with it inflated (RD). Lower urinary tract and anorectal parameters were compared between cycles.

KEY RESULTS

Ten children (seven UI, four recurrent UTIs, nine FC ± FI) were enrolled. Postvoid residual (PVR) increased (p = 0.02) with RD. No differences were observed in percent of bladder filling to expected bladder capacity, sensation, and bladder compliance with and without RD. Bladder and abdominal pressures increased at voiding with RD (p < 0.05). Intra-anal pressures decreased at voiding (p < 0.05), at 25% (p = 0.03) and 50% (p = 0.06) of total volume of bladder filling.

CONCLUSIONS & INFERENCES

The PVR volume increased with RD. Stool in the rectum does not alter filling cystometric capacity but decreases the bladder's ability to empty predisposing patients with fecal retention to UI and UTIs. Bladder and abdominal pressures increased during voiding, demonstrating a physiological correlate of voiding dysfunction. Intra-anal pressures decreased during bladder filling and voiding. This is the first time intra-anal relaxation during bladder filling and voiding has been described.

A large multicenter study analysis of adverse events associated with single operator cholangiopancreatoscopy

AIM

Cholangiopancreatoscopy (CP) is an endoscopic technique that allows for direct visualization of the biliary and pancreatic ducts using a narrow caliber endoscope that passes through the working channel of a duodenoscope directly into the bile and/or pancreatic ducts. Little data is available on the safety of CP. We performed a multicenter retrospective study to evaluate the frequency and severity of adverse events with single operator CP.

METHODS

A multicenter retrospective study was conducted.

RESULTS

A total of 282 single operator peroral CP procedures were performed in 224 patients (128 M, 96 F). Most procedures involved the performance of therapeutic maneuvers, with most cases including multiple therapeutic maneuvers. Cholangioscopic or pancreatoscopic-assisted tissue sampling was performed in 222 procedures. Thirty-seven patients underwent electrohydraulic lithotripsy (EHL) for the treatment of common bile duct stones. Adverse events in patients undergoing single cholangioscopy and pancreatoscopy included post-ERCP pancreatitis (N.=11, 3.9%, all mild), post-ERCP cholangitis (N.=4, 1.4%), bleeding (N.=3, 1%), and perforation (N.=2, 0.7%).

CONCLUSION

Overall, our data shows that ERCP performed with single operator cholangioscopy or pancreatoscopy is safe with adverse events similar to that seen in large studies of ERCP performed without these additional techniques. Of note, vigorous irrigation of the bile ducts was not associated with increased rates of post-procedure cholangitis in our study.