Blood transfusion, hospital stay and learning curve in robotic assisted total hip arthroplasty

Total Hip Arthroplasty (THA) has been defined the surgical procedure of the century considering its outcome and cost-benefit ratio (1). Both standard and robotic assisted procedures are increasing, thus, comparison between standard and robotic surgery become useful to understand the cost-benefit of the latter. The prerequisites of the robotic assisted arthroplasty are precision, accuracy, limitation of errors and safety but, on the other hand, its cost is the main drawback. The primary endpoint of our research was to evaluate differences in terms of blood transfusion rates between standard manual and robotic arm assisted THA. All the robotic procedures have been managed using semi active Robotic Arm interactive orthopaedic System (RIO® MAKO Stryker surgical corporation) in a group of patients who underwent primary uncemented total hip arthroplasty (THA) for osteoarthritis or avascular necrosis. Secondary endpoints were the evaluation of length of hospital stay (LOS), age category, gender and the impact of the learning curve on surgical time in the robotic surgery sample. Our retrospective cohort study was conducted between July 2014 and December 2018. Data have been collected from the Tuscany regional hospital discharge register, extracting the relative Hospital Discharge Forms (SDO). During the period of the study, 1537 patients underwent uncemented total hip arthroplasty for osteoarthritis or avascular necrosis. The sample was divided in two subgroups: 1142 patients (74.3%) operated on with standard manual technique and 395 patients (25.7%) operated on with Mako- Stryker Robotic System. In the descriptive analysis, the average values of age and days of hospitalization with 95% CI were calculated. Mean significance was assessed by the T student test. The association between surgical modality and gender was assessed with the chi-square test. The multivariate logistic regression model was used to evaluate the risk of transfusion (outcome variable), between conventional and robotic surgical techniques. The significance threshold was set up at p <0.05. During the period of the study we observed a decrease in standard surgery and an increase in robotic surgery; an increasing number of women per year underwent total uncemented total hip arthroplasty. We found a statistical significance in favor of robotic procedures in terms of transfusion percentage (OR 6.10, 95% CI 2.96-12.59, p<0,001), highlighting the greatest risk in women (OR 1.90, 95%CI 1.30-2.78, p=0.001 ), length of hospital stay (Mr=4.24, SD=2.04, 95% CI 4.04-4.44) (Ms=8.04, SD=2.84, 95%CI 7.88-8.21), (p<0.01). Operative time in the robotic sample decreased substantially with the rise of surgical experience (106.75±13.4 mins in 2014; 82.79±15.95 mins in 2018) (p<0.01). Since the Robotic procedure is a technologically demanding process, an adequate surgical learning curve is mandatory. Our paper, comparing conventional vs robotic assisted THA, showed in favor of the robotic one, a statistically significant reduction of number of transfusions (p<0.001) and length of hospital stay (p<0.01).

The Behavior of Heterolepidoderma sp. (Gastrotricha)

The behavior of Heterolepidoderma sp. was studied with the same approach as those already used for many species of ciliates. The ethogram we drew comprehends both helicoidal swimming (n = 20, r = 52.5 +/-12.2 mum, pitch = 512 +/- 101 mum, v--> = 215 +/- 43 mum/sec), periodically interrupted by irregular patterns changing the direction of the swimming of random angles and creeping on the substrate. The latter behavioral state, very common for the species we studied, occurs along tracks formed by successive elements (circular, C, vs linear segments, S) joined to each other by two kinds of reactions, which change their trajectory. The surprising similarities and the unexpected differences between the behavior of this gastrotrich and those of the ciliates already studied from this point of view are discussed, on the basis of the dimensional ranges and ecological niches shared by these two, definitely unrelated groups of organisms.

Importance of the biogenic organic matter in photo-formation of dissolved gaseous mercury in a culture of the marine diatom Chaetoceros sp

Laboratory experiments on DGM production under light/dark cycles in a culture of the marine diatom Chaetoceros sp. spiked with 200 ng l(-1) of mercury have been performed. DGM formation has been investigated also in the cell exudates, obtained by filtration of the cell culture. Results show that the cell culture and the filtrate give the same value of DGM production (2.24+/-0.88 pg min(-1) l(-1) and 2.23+/-0.02 pg min(-1) l(-1), respectively) in the light (40 W m(-2)), values much higher than to those obtained in the medium culture alone. A significant DGM production has been measured in dark conditions both in the cell culture (0.48+/-0.11 pg min(-1) l(-1)) and in the filtrate (0.85+/-0.10 pg min(-1) l(-1)). The results highlight that the organic compounds released by the cell in the culture medium play a fundamental role in the DGM photo-formation processes.

Ethogram of Aspidisca sedigita

The analysis of behaviour of Aspidisca sedigita has been undertaken to describe the main features of its biology. In drawing the standard ethogram of A. sedigita, several peculiarities have been discovered: (i) the cirri of Aspidisca are thicker and tufted versus the slim and pointed cirri of other hypotrichs; (ii) the side-stepping reaction is performed without its typical backward motion; (iii) a typical clockwise rotation of 90°, followed by a similar but anticlockwise one, is performed frequently and results in a shift of the creeping Aspidisca into a new trajectory, close and parallel to the previous one; (iv) the very rare swimming motion of the species occurs along a regular helicoid, with the ciliary organelles facing in the opposite direction of the centre of the helicoid; (v) the creeping and swimming of conjugating pairs are similar to those of single organisms. The analysis of behaviour of A. sedigita is suggested to contribute to our knowledge of the adaptive strategies of this species.

REGULAR ARTICLES / ARTICLES RÉGULIERSMovement of the cirri during the creeping of Euplotes crassus (Ciliata, Hypotrichida)

The beating cycle of several cirri (frontal cirri 1/0, 3/I, 3/II, 3/III; transverse cirri; one caudal cirrus) of the ciliate Euplotes crassus was studied and described thoroughly in specimens that were actually creeping along the substrate. The beating cycle of the frontal cirri was measured both spatially and temporally, and it was found that (i) the single beating cycle was formed by an active propulsion phase (about 70% of the single step), followed by a recovery phase that so far has never been described and is where the cirri are transferred forwards passively (about 30% of the step); (ii) whenever the euplotes stops, it assumes its "zero position," repositioning all of its frontal cirri to their respective "standard positions"; and (iii) at the beginning of a new creeping phase the frontal cirri were reactivated in a well-defined order. The transverse cirri were kept still during forward creeping, while their angular position was changed with respect to the substrate during the stops and backward movements of the ciliate. The first left caudal cirrus beats constantly and its operating cycle appeared to be independent of the creeping or immobile state of the organism. The findings are discussed from the functional point of view and in the context of available literature on the internal beating potentialities of the different cirri.

The behavior of the doublet of Oxytricha bifaria (Ciliata, Hypotrichida): a contribution to the understanding of this enigmatic form

The tracks of normal organisms of Oxytricha bifaria and of stage IA, IB, II, III, IV and V doublets were studied to test the hypothesis that the doublet might function as a dispersal form. Stage IA, the only stage to swim, swims straight with only rare interruptions; its rate of mobility (Rmo = 443 micro/s) is roughly twice that of singlets (Rmo = 218 micro/s). Stage IA doublets swim in three-dimensional movement which enables them to be carried away by water currents. The other stages seem to represent passage back towards the normal singlet form. The ethological evidence reported here together with other results already published supports the working hypothesis that the doublet of O. bifaria is a dispersal form suggests that the doublet might well represent a special fourth differentiation state of this species in addition to pairs, giants, and cysts.

Insulin treatment affects the behaviour of Tetrahymena pyriformis and T. malaccensis

Populations of Tetrahymena pyriformis and T. malaccensis were treated with insulin, then washed and treated again 24 h later. The ethograms of controls, treated, washed and retreated populations were drawn. Statistical analysis showed that T. pyriformis was affected by insulin more severely than T. malaccensis. In T. pyriformis the effects of the 'memory' of the first treatment seem to be more relevant than those of the first and second treatments themselves. On the contrary in T. malaccensis treatments with insulin per se seem to affect the behaviour more strongly than the memory of the first treatment itself. These results are discussed in detail in the context of previous work.

The interface between air and water: a perturbation source eliciting adaptive behaviour in ciliates

Interference with the water-air interface, both direct (by contact with a flat, rigid surface) and indirect (by inducing a meniscus) caused the ciliated protozoa we investigated to actively collect in the water column or on the substrate directly under the area of altered surface tension. A crowding effect is observed in this "rest area" reaching plateau values within one hour after onset of the experiment. The simple experimental procedures described here induced analogous behaviour in both Paramecium caudatum (a swimmer) and Oxytricha bifaria (a crawler). The ciliates seem in this reaction to be seeking a refuge from vibrations transmitted by the free interface. Our discovery is discussed in its implications for the adaptive biology and ecology of these micro-organisms.

Effect of streptomycin on the structure and function of the photoreceptor apparatus of Euglena gracilis

The progressive modification of the photoreceptor apparatus, induced by addition of streptomycin (SM) to cultures of dark-bleached Euglena, is correlated with the change of the photomotor response. One of the effects of drug-treatment is the reduction of carotenoid synthesis; the total carotenoid content decreases from 0.20 to 0.01 pg/cell after seven weeks of treatment. The parallel progressive reduction of the stigma vesicles and their carotenoid content is observed by electron microscopy. Micrographs and microscopic fluorescence observations do not indicate alterations of the paraflagellar body (PFB). During the SM-treatment the initial positive phototactic response decreases until it disappears after five weeks. The loss of the absorbing properties of the stigma prevents the cell from orienting itself towards the light. The probability that the cell orients seems to depend on the light modulation amplitude and the light/dark ratio on the PFB due to the shading device. After seven weeks of SM-treatment we observe a cell movement away from the illuminated zone. The mechanism of this escape is discussed.