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1.
Orthop Surg ; 16(4): 943-952, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38433589

ABSTRACT

OBJECTIVE: Minimally invasive atlantoaxial surgery offers the benefits of reduced trauma and quicker recovery. Previous studies have focused on feasibility and technical aspects, but the lack of comprehensive safety information has limited its availability and widespread use. This study proposes to define the feasibility and range of surgical safety using the intersection of the greater occipital nerve and the inferior border of the inferior cephalic oblique as a reference point. METHODS: Dissection was performed on 10 fresh cadavers to define the anatomical reference point as the intersection of the greater occipital nerve and the inferior border of the inferior cephalic oblique muscle. The study aimed to analyze the safety range of minimally invasive atlantoaxial fusion surgery by measuring the distance between the anatomical reference point and the transverse foramen of the axis, the distance between the anatomical reference point and the superior border of the posterior arch of the atlas, and the distance between the anatomical reference point and the spinal canal. Measurements were compared using Student's t test. RESULTS: The point where the occipital greater nerve intersects with the inferior border of the inferior cephalic oblique muscle was defined as the anatomical marker for minimally invasive posterior atlantoaxial surgery. The distance between this anatomical marker and the transverse foramen of the axis was measured to be 9.32 ± 2.04 mm. Additionally, the distance to the superior border of the posterior arch of the atlas was found to be 21.29 ± 1.93 mm, and the distance to the spinal canal was measured to be 11.53 ± 2.18 mm. These measurement results can aid surgeons in protecting the vertebral artery and dura mater during minimally invasive posterior atlantoaxial surgery. CONCLUSIONS: The intersection of the greater occipital nerve with the inferior border of the inferior cephalic oblique muscle is a safe and reliable anatomical landmark in minimally invasive posterior atlantoaxial surgery.


Subject(s)
Cervical Vertebrae , Minimally Invasive Surgical Procedures , Humans , Cervical Vertebrae/surgery , Vertebral Artery , Cadaver
2.
J Neurosci ; 43(47): 8018-8031, 2023 11 22.
Article in English | MEDLINE | ID: mdl-37752000

ABSTRACT

The identifiable target effect refers to the preference for helping identified victims and punishing identifiable perpetrators compared with equivalent but unidentifiable counterparts. The identifiable target effect is often attributed to the heightened moral emotions evoked by identified targets. However, the specific neurocognitive processes that mediate and/or modulate this effect remain largely unknown. Here, we combined a third-party punishment game with brain imaging and computational modeling to unravel the neurocomputational underpinnings of the identifiable transgressor effect. Human participants (males and females) acted as bystanders and punished identified or anonymous wrongdoers. Participants were more punitive toward identified wrongdoers than anonymous wrongdoers because they took a vicarious perspective of victims and adopted lower reference points of inequity (i.e., more stringent norms) in the identified context than in the unidentified context. Accordingly, there were larger activity of the ventral anterior insula, more distinct multivariate neural patterns in the dorsal anterior insula and dorsal anterior cingulate cortex, and lower strength between ventral anterior insula and dorsolateral PFC and between dorsal anterior insula and ventral striatum connectivity in response to identified transgressors than anonymous transgressors. These findings implicate the interplay of expectancy violations, emotions, and self-interest in the identifiability effect. Last, individual differences in the identifiability effect were associated with empathic concern/social dominance orientation, activity in the precuneus/cuneus and temporo-parietal junction, and intrinsic functional connectivity of the dorsolateral PFC. Together, our work is the first to uncover the neurocomputational processes mediating identifiable transgressor effect and to characterize psychophysiological profiles modulating the effect.SIGNIFICANCE STATEMENT The identifiable target effect, more help to identified victims or stronger punishment to identifiable perpetrators, is common in daily life. We examined the neurocomputational mechanisms mediating/modulating the identifiability effect on third-party punishment by bridging literature from economics and cognitive neuroscience. Our findings reveal that identifiable transgressor effect is mediated by lower reference points of inequity (i.e., more stringent norms), which might be associated with a stronger involvement of the emotion processes and a weaker engagement of the analytic/deliberate processes. Furthermore, personality traits, altered brain activity, and intrinsic functional connectivity contribute to the individual variance in the identifiability effect. Overall, our study advances the understanding of the identifiability effect by shedding light on its component processes and modulating factors.


Subject(s)
Brain , Punishment , Male , Female , Humans , Punishment/psychology , Brain/diagnostic imaging , Brain/physiology , Emotions/physiology , Brain Mapping , Empathy , Magnetic Resonance Imaging
3.
Heliyon ; 9(3): e13818, 2023 Mar.
Article in English | MEDLINE | ID: mdl-36895346

ABSTRACT

Sustainable fisheries management depends on the degree of the present exploitation status of significant fish stocks. A recently developed fish stock assessment approach, CMSY, was used to estimate the fisheries reference points of data-limited Gudusia chapra and Corica soborna from the Kaptai reservoir using catch data, resilience, and exploitation records during the first and last year of the time series catch data. CMSY, along with a Bayesian state-space Schaefer production model (BSM), estimated maximum sustainable yield (MSY) as 2680 mt and 2810 mt, and 3280 mt and 3020 mt for the above stocks, respectively. The MSY range for both stocks was higher than the last catches meaning that both stocks are perfectly sustainable. The lower biomass B (4340 mt) for G. chapra estimated by CMSY and B MSY (4490 mt) indicates that the stock has started to be depleted. However, considering the precautionary fisheries management, the lower limit of MSY might be suggested to follow. Therefore, it could be suggested not to exceed the MSY limit (2680 mt) for the sustainability of G. chapra stock while it was 3020 mt for the C. soborna fishery. The intrinsic growth rate r was 0.862-1.19 yr-1 for G. chapra and 0.428-0.566 yr-1 for C. soborna, suggesting a high and medium increase of biomass in the existing population, respectively. A F/F MSY less than 1 and B/B MSY greater than 1 report both stocks at underfishing and underfished states. The study recommends enforcing strict and lawful actions regarding the net's mesh size to catch less small fish. Otherwise, negligence of this crucial management practice may bring severe threats to the sustainability of the whole reservoir resources and the reservoir ecosystem.

4.
J Behav Exp Econ ; 103: 101983, 2023 Apr.
Article in English | MEDLINE | ID: mdl-36714370

ABSTRACT

We study the behavioral impact of announcements about the duration of a policy and their relationship with people's expectations in the context of the COVID-19 lockdowns. We surveyed representative samples of Italian residents at three moments of the first wave of the pandemic to test how intentions to comply with social-isolation measures depend on the duration of their possible extension. Individuals were more likely to reduce, and less likely to increase, their compliance effort if the hypothetical extension was longer than they expected, whereas positive surprises had a lesser impact. The behavioral response to the (mis)match between expected versus hypothesized extensions is consistent with expectations acting as reference points and can help explain the increase in observed physical proximity in Italy following lockdown extension announcements. Our findings suggest that public authorities should consider citizens' expectations when announcing policy changes.

5.
Psychon Bull Rev ; 30(2): 731-738, 2023 Apr.
Article in English | MEDLINE | ID: mdl-36219372

ABSTRACT

Although all birth orders in the "birth sequence problem" are equiprobable, most participants judge the less representative order as less likely than the more representative order. But this well-known problem confounds representativeness with the direction in which birth orders are compared. We hypothesized and corroborated in three experiments (total N = 1,136) that participants pragmatically infer the birth orders' relative prevalence from the direction of comparison. Experiment 1 found that participants judged the less representative sequence as more common when we reversed the comparison. Experiment 2 reproduced these results despite removing representativeness as a cue. In Experiment 3, participants preferred to place the relatively common sequence as the referent in an inverted "speaker" problem. Our results turn the iconic problem's interpretation on its head: Rather than indicating flawed human cognition, the birth sequence problem illustrates people's ability to adaptively extract subtle linguistic meaning beyond the literal content.


Subject(s)
Cognition , Judgment , Humans , Linguistics , Orientation, Spatial
6.
Article in English | MEDLINE | ID: mdl-36361351

ABSTRACT

The environmental maintenance of public dining spaces significantly impacts urban construction's sustainable and healthy development. This paper studied the influence of image-text information tailoring relationships on behavioral intentions to promote public dining space environment maintenance. We used a two-factor between-subject experimental design, two (image reference points: self vs. others) × two (text appeals: feasibility vs. desirability). We also examined the mediating roles of environmental maintenance attitudes and environmental responsibility perceptions as regards pro-environmental behavioral intentions. The research results showed the following: (1) Among the four image-text information construction methods, the other's image reference point with the desirability text appeal promotes the diners' pro-environmental behavioral intention with optimal effectiveness; and (2) Environmental maintenance attitudes and environmental responsibility perceptions play mediating roles in promoting diners' intention to maintain environmental behavior in the image-text combined information presentation. Environmental responsibility perceptions cannot be mediated alone and must be progressively mediated with environmental maintenance attitudes.


Subject(s)
Intention , Text Messaging , Attitude , Environment
7.
Front Psychol ; 12: 758990, 2021.
Article in English | MEDLINE | ID: mdl-34887809

ABSTRACT

People can use social or personal information as a reference point against which they compare their performance. While previous research has shown that reference point choice can be affected by individual characteristics, situational factors, and goals, we suggest that properties of the performance feedback itself can also play a role in this choice. We focus on the effects of round vs. precise numerical feedback on reference point preferences. In three studies, we show that people are more likely to use themselves as a reference point to evaluate their performance following a feedback in the form of a round score (e.g., a score of 70 in a task) and to use others as a reference point following a precise score (e.g., a score of 71). Study 1 shows decreased interest in comparisons with others following round rather than precise feedback. Study 2 shows that round (vs. precise) feedback also increases actual choice of the self (vs. others) as a reference point. Study 3 demonstrates that the effect of the numerical feedback on reference point preferences extends to the choice of a benchmark for future comparisons. We discuss the implications of our results for the literature and practice, including how this can be used to encourage desirable behaviors.

8.
Front Psychol ; 12: 597758, 2021.
Article in English | MEDLINE | ID: mdl-34621202

ABSTRACT

Many researchers use the term "context" loosely to denote diverse kinds of reference points. The issue is not about terminology but rather about the common conflation of one kind of reference points, such as rules of perception, which is responsible for optical illusions, with another kind, known as "context" or "frame," as exemplified in Rubin's vase. Many researchers regard Rubin's vase as a special kind of optical illusions. This paper rather argues that the two phenomena are radically different. Optical illusions are occasional mistakes that people quickly recognize and eagerly correct, while the different figures of Rubin's vase are not mistakes but, rather, the outcomes of different perspectives that do not need correction. The competing figures in Rubin's vase can, at best, in light of more information, be more warranted or unwarranted. This paper discusses at length one ramification of the proposed distinction. The framing effects, such as loss/gain frame, are the products of contexts and, hence, resemble greatly the figures in Rubin's vase. In contrast, cognitive illusions generated occasionally by the rules of thumb (heuristics) are mistakes and, hence, resemble optical illusions. The proposed distinction carries other ramifications regarding, e.g., happiness studies, moral judgments, and the new philosophy of science.

9.
Health Econ ; 30(11): 2766-2779, 2021 11.
Article in English | MEDLINE | ID: mdl-34414631

ABSTRACT

In the evaluation of well-being, it is not only important what people have in absolute terms, but also how this compares to reference points in relative terms. We explore the relevance of relative comparisons by testing the effect of people's self-rated position on potential reference points for income and health on their subjective well-being. We used Multiple Discrepancies Theory as a framework to identify seven potentially relevant reference points for income and health. A representative sample (N = 550) of the Netherlands assessed their income and health relative to these reference points. In addition, we elicited monthly household income, health status (EQ-5D-5L), and subjective well-being (SWLS). In line with the literature, we found a negative convex relationship between subjective well-being and age and a positive relationship with being employed, income, and health. For income, subjective well-being was also associated with how current income compared to respondents' needs and progression over time, and for health especially with how current health compared to what they felt they deserved. Our findings suggest that income and health are important for subjective well-being both in absolute and relative terms. We found negative effects on life satisfaction if some of the domain specific reference points were not met.


Subject(s)
Health Status , Quality of Life , Emotions , Humans , Income , Netherlands , Surveys and Questionnaires
10.
Stomatologiia (Mosk) ; 100(4): 63-67, 2021.
Article in Russian | MEDLINE | ID: mdl-34357730

ABSTRACT

THE AIM OF THE STUDY: Was to investigate the efficiency of decoding teleradiological studies using an algorithm based on the use of convolutional neural networks - a simple convolutional architecture, as well as an extended U-Net architecture. MATERIALS AND METHODS: For the experiment, a dataset was prepared by three orthodontists with over 10 years of clinical experience. Each of the orthodontists processed 100 X-ray images of the lateral projection of the head according to 27 parameters, 2700 measurements were made. The coordinates of the control points found by orthodontists in the images were compared with each other and a conclusion was made about the consistency of experts in the data obtained. RESULTS: The results of convolutional neural network CNN were not satisfactory in 17 (62.96%) features, satisfactory in 10 (37.04%). The assessment of orthodontists resulted in non-satisfactory evaluation in 6 (22.22%), satisfactory in 8 (29.63%), good in 8 (29.63%), and excellent in 5 (18.52%) coordinates. Neural networks with U-Net architecture showed satisfactory results in 9 (33.3%) cases, good in 16 (59.3%) and excellent in 2 (7.4%) cases, with no non-satisfactory results. CONCLUSION: The neural network of the U-Net architecture is more effective than a simple fully convolutional neural network and its results of determining anatomical reference points on two-dimensional images of the head are relatively comparable with the data obtained by medical specialists.


Subject(s)
Neural Networks, Computer , Skull , Cephalometry , Humans , Image Processing, Computer-Assisted , Radiography , Skull/diagnostic imaging , X-Rays
11.
Cognition ; 215: 104822, 2021 10.
Article in English | MEDLINE | ID: mdl-34246915

ABSTRACT

When people make financial decisions, they need not only think about their current financial situation, but also about changes in future wealth. This work investigates people's beliefs about their future wealth and how these beliefs impact financial decisions. Using a joint experimental and computational cognitive modeling approach, we show that people's future beliefs serve as reference points when making investment decisions. These results are further supported by data from a large-scale cross-sectional survey (n = 4606) showing that people's beliefs about the future value of their assets are related to investment decisions between risky (i.e., stock market index) and safe (i.e., bond earning a fixed amount per year) options. In both the experiments and survey, we hypothesize that outcomes that are nominally stated as sure gains can become coded as losses due to belief-based reference points. This pattern leads to an increase in riskier choices across positive outcomes for individuals with optimistic beliefs about their future wealth.


Subject(s)
Decision Making , Risk-Taking , Cross-Sectional Studies , Humans , Income , Investments
12.
Front Psychol ; 11: 1406, 2020.
Article in English | MEDLINE | ID: mdl-32733320

ABSTRACT

We examine the conceptualization of space in signed language discourse within the theory of cognitive grammar. Adopting a Places view, we define Place as a symbolic structure that associates a schematic semantic pole and a schematic phonological pole. Places acquire full contextual meaning and a specific spatial location in the context of a usage event. In the present article, we analyze the referential function of Places in different grammatical constructions throughout a selection of videos produced by deaf Argentine Sign Language signers. Our analysis examines Places, which are associated with entities in the surrounding spatial environment as well as Places that are created or recruited in discourse without reference to surrounding physical entities. We observe that Places are used in pointing, placing, and other grammatical constructions in order to introduce and track referents in ongoing discourse. We also examine the use of conceptual reference points, by which Places afford mental access to new related concepts that are the intended focus of attention. These results allow us to discuss three related issues. First, for signed language discourse, space is both semantically and phonologically loaded. Signers' semantic and phonological choices for Place symbolic structures are motivated by embodied experience and the abstraction of usage events. Second, Places occur along a continuum from deixis to anaphor, united by the same conceptual system and differing in extent of phonological subjectification. Third, we suggest developmental implications of our Place analysis.

13.
Cognition ; 203: 104334, 2020 10.
Article in English | MEDLINE | ID: mdl-32534218

ABSTRACT

Research on reference points highlights how alternatives outside the choice set can alter the perceived value of available alternatives, arguably framing the choice scenario. The present work utilizes reference points to study the effects of framing in preferential choice, using the similarity and attraction context effects as performance measures. We specifically test the predictions of Multialternative Decision by Sampling (MDbS; Noguchi & Stewart, 2018), a recent preferential choice model that can account for both reference points and context effects. In Experiment 1, consistent with predictions by MDbS, we find a standard similarity effect when no reference point is given that increases when both dimensions are framed negatively and decreases when both dimensions are framed positively. Contrary to predictions by MDbS, when the two dimensions are framed as tradeoffs, participants prefer whichever alternative performs best in the negatively framed dimension. Performance of MDbS was improved by the addition of a frame-based global attention allocation mechanism. Experiment 2 extends these results to a "by-dimension" presentation format in an attempt to bring participant behavior in line with MDbS assumptions. The empirical and modeling results replicated those of Experiment 1. Experiment 3 used the attraction effect to test the effects of framing when the best-performing alternative on each dimension was identical across target conditions, therefore reducing the potential effects of a global attention allocation mechanism. The effects of framing were indeed greatly reduced, and the performance of MDbS was markedly improved. The results extend framing to the context effects literature, provide new benchmarks for models and theories of context effects, and point to the need for a global attention mechanism.


Subject(s)
Choice Behavior , Humans
14.
Int J Neural Syst ; 30(5): 2050023, 2020 May.
Article in English | MEDLINE | ID: mdl-32380924

ABSTRACT

The training procedure of the minimal learning machine (MLM) requires the selection of two sets of patterns from the training dataset. These sets are called input reference points (IRP) and output reference points (ORP), which are used to build a mapping between the input geometric configurations and their corresponding outputs. In the original MLM, the number of input reference points is the hyper-parameter and the patterns are chosen at random. Therefore, the conventional proposal does not consider which patterns will belong to each reference point group, since the model does not implement an appropriate way of selecting the most suitable patterns as reference points. Such an approach can impact on the decision function in terms of smoothness, resulting in high complexity models. This paper introduces a new approach to select IRP for MLM applied to classification tasks. The optimally selected minimal learning machine (OS-MLM) relies on the multiresponse sparse regression (MRSR) ranking method and the leave-one-out (LOO) criterion to sort the patterns in terms of relevance and select an appropriate number of input reference points, respectively. The experimental assessment conducted on UCI datasets reports the proposal was able to produce sparser models and achieve competitive performance when compared to the regular strategy of selecting MLM input RPs.


Subject(s)
Machine Learning , Models, Theoretical , Pattern Recognition, Automated , Humans , Regression Analysis
15.
Curr Biol ; 30(9): 1680-1688.e4, 2020 05 04.
Article in English | MEDLINE | ID: mdl-32197086

ABSTRACT

The retrosplenial cortex (RSC) is involved in a broad range of cognitive functions, integrating rich sensory, motor, and spatial signals from multiple brain areas, including the hippocampal system. RSC neurons show hippocampus-dependent activity reminiscent of place cell sequences. Using cellular calcium imaging in a virtual reality (VR)-based locomotion task, we investigate how the integration of visual and locomotor inputs may give rise to such activity in RSC. A substantial population shows neural sequences that track position in the VR environment. This activity is driven by the conjunction of visual stimuli sequences and active movement, which is suggestive of path integration. The activity is anchored to a reference point and predominantly follows the VR upon manipulations of optic flow against locomotion. Thus, locomotion-gated optic flow, combined with the presence of contextual cues at the start of each trial, is sufficient to drive the sequential activity. A subpopulation shows landmark-related visual responses that are modulated by animal's position in the VR. Thus, rather than fragmenting the spatial representation into equivalent locomotion-based ensemble versus optic-flow-based ensemble, in RSC, optic flow appears to override locomotion signals coherently in the population, when the gain between the two signals is altered.


Subject(s)
Gyrus Cinguli/physiology , Locomotion/physiology , Space Perception/physiology , Spatial Processing/physiology , Visual Perception/physiology , Animals , Mice
16.
J Gen Psychol ; 147(2): 123-139, 2020.
Article in English | MEDLINE | ID: mdl-31530233

ABSTRACT

The development of society and the economy has given rise to housing demolition. Using the psychological perspective of reference points, this paper studied the effects of tri-reference points (TRP) and social comparison on demolition compensation fairness perception through experiments in a demolished community. According to TRP theory, there are three special reference points (minimum requirements, status quo, and goal) when people make decisions. Our research finds that there exists a dual value orientation in the demolition compensation process: before the compensation amount reaches the status quo, the individual's economic value orientation dominates; after achieving the status quo, a social equity value orientation dominates. In addition, the research results also show that demolished households pay the most attention to the minimum requirements of compensation; the fairness perception is very low below the minimum requirements, even when the compensation amount is the same or higher than that of others. Therefore, in the future implementation of compensation for demolition, the minimum requirements should be taken as the first priority. It is not necessary to arbitrarily increase the amount of compensation; it is better to set it between the status quo and the goal. Finally, ensuring that the demolished households are treated equally is very important.


Subject(s)
Compensation and Redress , Decision Making , Housing/economics , Social Values , Urban Renewal/economics , Humans
17.
Front Psychol ; 9: 1990, 2018.
Article in English | MEDLINE | ID: mdl-30386283

ABSTRACT

This article addresses the timely subject of the reactions toward a Sunday trade ban in Poland. The law introduced in March 2018 created a division among service employees: (1) those who used to work on Sundays before the law and now enjoy work-free Sundays, and (2) those who used to work and still have to work on Sundays. Although the objective circumstances did not change for this latter group, their current status quo (0) now had a new better state (+1) as a contrast reference point. Hence, this group experiences a non-gain rather than a loss. Using the framework of regulatory focus (Higgins, 1997) and regulatory fit (Higgins, 2000) theories, we predicted that the individuals in the non-gain condition would process a promotion (vs. prevention)-framed message more fluently. We also predicted that processing fluency would enhance fairness perceptions among these employees. To test these predictions, we conducted a field experiment, manipulating message framing among two groups of service employees: those who gained and those who did not gain as a result the Sunday trade ban. Analysis of variance revealed that employees in a non-gain promotion framing condition processed the message more fluently than those in a prevention framing condition. A moderated mediation analysis also showed that the processing fluency resulting from fit created higher fairness perceptions. Repercussions for communicating about organizational non-gain changes are discussed.

18.
Front Psychol ; 9: 686, 2018.
Article in English | MEDLINE | ID: mdl-29872409

ABSTRACT

Within a risky choice framework, we examine how multiple reference points and anchors regulate pay perception and turnover intentions in real organizational contexts with actual employees. We hypothesize that the salary range is psychologically demarcated by three reference points into four regions, the minimum requirement (MR), the status quo (SQ), and the goal (G). Three studies were conducted: Study 1 analyzed the relationship between turnover intention and the subjective likelihood of falling into each of four expected salary regions; Study 2 tested the mediating effect of pay satisfaction on salary reference point-dependent turnover intention; and Study 3 explored the anchoring effect of estimated peer salaries. The results show that turnover intention was higher in the region below MR or between SQ and G but lower in the region above G or between MR and SQ. That is, turnover intention can be high even in situations of salary raise, if the raise is below a salary goal (i.e., leaving for a lack of opportunity) and low even in situations of salary loss, if the expected salary is still above the MR (i.e., staying for security). In addition, turnover intention was regulated by pay satisfaction and peer salaries. In conclusion, turnover intention can be viewed as a risky choice adapted to salary reference points.

19.
Proc Natl Acad Sci U S A ; 115(8): 1772-1776, 2018 02 20.
Article in English | MEDLINE | ID: mdl-29434043

ABSTRACT

Personal bests act as reference points. Examining 133 million chess games, we find that players exert effort to set new personal best ratings and quit once they have done so. Although specific and difficult goals have been shown to inspire greater motivation than vague pronouncements to "do your best," doing one's best can be a specific and difficult goal-and, as we show, motivates in a manner predicted by loss aversion.


Subject(s)
Achievement , Video Games/psychology , Algorithms , Female , Goals , Humans , Male , Models, Statistical , Motivation
20.
J Orthod ; 44(1): 8-13, 2017 03.
Article in English | MEDLINE | ID: mdl-28248616

ABSTRACT

INTRODUCTION: The purpose of this study was to evaluate the accuracy of Le Fort I surgery by comparing planned surgical movements with actual outcomes. MATERIALS AND METHODS: A minimum number of seven consecutive cases that had undergone a Le Fort I osteotomy procedure alone or in combination with a mandibular osteotomy from six different hospital units in the East of England between 2009 and 2010 were identified. A total of 56 cases met the inclusion criteria where surgical splints were used and model surgery had been performed. Pre- and post-operative lateral cephalograms were digitised using Dolphin© imaging software (Version 10.0) and three cephalometric points were assessed to measure precision of surgical movements: A point (A-pt); Upper incisor tip (U1 tip); and Upper first molar occlusal point (U6 occ). The final position of the maxilla was compared to the planned position. RESULTS: In 71% of cases surgical movements were within 2 mm and 20% of this group were within 1 mm of the predicted position. The mean accuracy was 1.39 mm (SD 0.92 mm) for the former and 0.78 mm (SD 0.58 mm) for the latter. Accuracy correlated negatively with increased surgical complexity, particularly posterior differential impactions of the maxilla. There was no statistically significant difference between centres. CONCLUSIONS: Pre-operative surgical planning of Le Fort I osteotomies was generally accurate. This study demonstrates that different operators across six centres produced consistent surgical outcomes and this confirms previously reported data.


Subject(s)
Maxilla , Osteotomy, Le Fort , Cephalometry , Retrospective Studies , Treatment Outcome
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