Current insights into lower limb prostheses: Brazilian users’ perceptions on the (Re)construction of body image and identity

Throughout the evolutionary history of humans, the body has been present in different moments and social contexts, serving as the main mediator in the construction of relationships between individuals and society. Beliefs, values and social customs are inscribed on the body, and through the body image, physical characteristics, cultural and representative choices, as well as the identity of each individual, are presented (Tessari et al., 2010; Tiggemann, 2011; Cairns et al., 2014; Daniels and Gillen, 2015).

Physical appearance is a relevant factor in society because it carries with it personal characteristics and representative choices of each individual according to the different social contexts in which they participate. Since different social standards are created, they can either unite individuals who identify with them or segregate those who do not fit into these standards. Presenting an image that resembles the established dominant standard within a society becomes an ideal to be achieved, especially for individuals who are outside of these previously constructed standards, such as amputees (Phillips, 1985; Murray and Forshaw, 2013a).

For amputees who have alterations in their bodies, such as the absence of a limb, the pursuit of an appearance similar to pre-established social standards becomes an ideal to be achieved since such modifications in the body image are still a factor that causes discomfort for both amputees and society. This discomfort may be associated with the stigmas of disability or incapacity constructed in the past (Kaiser et al., 1985; Horgan and MacLachlan, 2004; Hosseini and Padhy, 2023). Amputation involves the removal of a part of a limb or its entirety, aiming to improve an individual’s quality of life. Its performance is indicated to meet the needs of each user, such as the functional return, sports practice, as well as the reconstruction of the altered body image (Hosseini and Padhy, 2023; Demirdel and Ülger, 2021).

Orthopedic prostheses are devices indicated for individuals who have undergone amputation and have been present since ancient times in human history, being made in a rustic way using iron and wood to replace a limb or part of it (O'Keeffe and Rout, 2019). Nowadays, these devices directly contribute to the process of (re)insertion and social acceptance of amputees because they not only promote the recomposition of the body image but also re-establish the relationship between the individual with themselves and with society by promoting the functionality lost after amputation (Marasco et al., 2011; Holzer et al., 2014; Ostler et al., 2022). Among the many professionals involved in the rehabilitation process, occupational therapists play an essential role. They are crucial in the rehabilitation of amputees, significantly enhancing the integration of prosthetics into their daily lives. Occupational therapists support both the emotional and functional adaptation of patients, preparing them for the use of assistive devices and aiding in their overall recovery, which improves their quality of life (Klarich and Brueckner, 2014 (Klarich and Brueckner, 2014)).

The meaning behind orthopedic prostheses and their importance in representing the body image of amputees are increasingly being recognized as significant factors in the social contexts in which these individuals are involved. Although there are studies addressing the use of prostheses (Murray and Forshaw, 2013b; Dunne et al., 2015; Norlyk et al., 2016; Jefferies et al., 2017)), research specifically exploring the user’s perspective and their perception of the prosthesis as an integral part of their body, as well as its role in the (re)construction of body image (Murray and Fox, 2002; Murray, 2004; Senra et al., 2011) and identity (Murray, 2008), remains limited, particularly in the Brazilian population and in recent times. An updated study can provide valuable and current data, considering changes in context and technology. In Brazil, over 282,000 lower limb amputations were performed within the Brazilian Unified Health System (SUS) from January 2012 to May 2023 (Sociedade Brasileira de Angiologia e Cirurgia Vascular (SBACV), 2023). In 2022 alone, there were 31,190 amputations, averaging 85 per day. Preliminary data for 2023 suggest a continuation of this trend, with 12,753 surgeries performed by May, compared to 12,350 in the same period of 2022 (Sociedade Brasileira de Angiologia e Cirurgia Vascular (SBACV), 2023).

Geographically, the Southeast and Northeast regions account for the majority of cases, with 118,962 and 92,265 amputations respectively. These disparities are attributed to factors such as population density, healthcare infrastructure and socioeconomic inequalities (Sociedade Brasileira de Angiologia e Cirurgia Vascular (SBACV), 2023). The increase in amputations also has a substantial impact on public spending, with approximately US$15.74m allocated for these procedures in 2022 and a total of US$159.8m from 2012 to 2022, reflecting an average cost of US$592.46 per surgery (Sociedade Brasileira de Angiologia e Cirurgia Vascular (SBACV), 2023; Instituto Brasileiro de Geografia e Estatística (IBGE), 2023).

Culturally, amputations are often stigmatized in Brazil, and prevailing beauty standards do not accommodate the diversity of prosthetics, negatively affecting amputees’ self-image (Schoeller et al., 2013; Silva, 2023). Access to prosthetics varies between the public and private sectors, and ongoing public policies aim to enhance rehabilitation (Caro et al., 2014). Additionally, the Brazilian Institute of Geography and Statistics (IBGE) data highlight significant challenges in social inclusion and employment, with a 26.6% employment rate for people with disabilities compared to 60.7% for those without (Instituto Brasileiro de Geografia e Estatística (IBGE), 2023).

This study explores the (re)construction of body image and identity among Brazilian individuals using orthopedic prostheses, analyzed from a phenomenological perspective based on users’ experiences. It specifically explores how prostheses affect the way individuals with amputations perceive their own bodies and identities, examining their experiences and narratives regarding the prosthesis and its impact on their personal and body identity. By expanding our understanding of how amputees in Brazil perceive their identity and body image, this research provides valuable insights into the personal and social impacts of prostheses. These findings can inform clinical practices and support strategies to enhance the rehabilitation and integration process for amputees.

This is a qualitative descriptive study using thematic analysis, grounded in phenomenology. It involved individuals with lower limb amputation who use orthopedic prostheses.

Participants were recruited from the South-Central Rehabilitation Center (CREAB), a municipal facility in Belo Horizonte, Minas Gerais, Brazil, where they received treatment. The inclusion criteria were patients with lower limb amputations, of both sexes, who used orthopedic prostheses. All participants received their prostheses at no cost through the Brazilian Unified Health System (SUS).

The researchers were familiar with the institution and the healthcare professionals responsible for the participants’ care. Two researchers, including the interviewer, had experience in amputee rehabilitation and prosthetic management, which helped guide the interview process and the interpretation of participants’ responses, while respecting their subjective perspectives. Participants were recruited at CREAB during rehabilitation sessions, and interviews were scheduled afterward.

Data were collected through face-to-face semi-structured interviews, guided by a script with open-ended questions. These questions addressed sociodemographic information, users’ perceptions of their orthopedic prostheses, and their reflections on its use (Cohen and Crabtree, 2006). All interviews were conducted by one of the researchers, who had experience in amputee rehabilitation and prosthetic management and was not known to any of the participants prior to the research interviews. The researcher conducted the interviews with an open mind, avoiding assumptions and encouraged participants to express their thoughts in their own words and speak freely. The interviews lasted approximately one hour, were audio-recorded, and were subsequently transcribed for analysis. To ensure anonymity, participants were identified only by the interview number, the duration since prosthetic fitting and the level of amputation, which was categorized as transfemoral (TF) or transtibial (TT).

This study was approved by the Research Ethics Committee of FUMEC University under the number C.A.A.E: 03278018.7.0000.5155, and individuals who agreed to voluntarily participate in the study signed an Informed Consent Form.

Thematic analysis, grounded in phenomenology, was employed to uncover the essence of the participants’ lived experiences. This process involved three stages: 1) pre-analysis, where the material was organized; 2) exploration of the material, where data were coded, transformed into units, and grouped according to themes; and 3) data treatment and interpretation, where these units were classified into superordinate and subordinate themes (Sundler et al., 2019). The phenomenological foundation ensured that the analysis reflected participants’ subjective experiences and meanings, offering a deeper understanding of how prostheses influence their body image and identity.

The procedures of this study included strategies to ensure trustworthiness throughout the research process. In line with qualitative research standards, these strategies also addressed essential factors such as internal coherence – ensuring that the argument presented was consistent and supported by the data – and the presentation of evidence, where sufficient data from participants’ discourse were provided to allow the reader to assess the interpretations (Rose and Johnson, 2020; Creswell et al., 2007; Shenton, 2013).

This study involved 16 individuals with lower limb amputations, using orthopedic prostheses. The sample consisted of 3 transfemoral (19%) and 13 transtibial amputees (81%), with ages ranging from 18 to 45 years (mean age 36 years, ± eight years). The group included 2 were women (13%) and 14 were men (87%). The duration of prosthesis use varied: 7 participants (44%) for up to 5 years, 2 (13%) for over 5 but up to 10 years, 2 (13%) for over 10 but up to 15 years, 1 (7%) for over 15 but up to 20 years and 4 (26%) for over 20 years. Of the 16 participants, 15 had unilateral amputations (7 right, 8 left) and 1 had bilateral amputations. This distribution is important for understanding the variation in prosthesis use and its impact on participants’ experiences.

The results were organized into two main superordinate themes with a total of six subordinate themes (Table 1): “Representativeness of the orthopedic prosthesis” and “Considerations about the use of the prosthesis.” The first superordinate theme was divided into three subordinate themes: “The prosthesis as part of me,” “What the prosthesis provides me,” and “It means everything to me.” The second superordinate theme was subdivided into three additional subordinate themes: “Feelings about using the prosthesis,” “Difficulties in users’ daily lives,” and “The gaze of others.”

Orthopedic prostheses are devices that hold great significance in the representation of the bodies of amputees. They provide for the (re)construction of the body image and identity, both of which are often impacted by amputation. Participants in this study expressed that prostheses are fundamental devices for the recomposition of the body image and play a role in the construction of one’s identity:

• The prosthesis as part of me.

According to user reports, the use of orthopedic prosthesis have become part of their routine and often replace the lost limb: “It represents part of me. It’s my leg. […] The prosthesis is my natural limb” (1, 24p - TT). “It’s already a part of me, like it’s my normal leg” (9, 10p - TT).

However, some participants reported that prostheses are merely devices that recompose their body image, without showing greater appreciation or involvement with their devices: “It recomposes my image because with it, people don’t see me as having a missing body part” (7, 3p - TT). “When I wear long pants, visually, my leg looks the same as if I had two legs” (6, 4p - TT).

• What the prosthesis provides me.

Participants’ reports indicated that with the use of the prosthesis, their functionalities, such as returning to work, practicing sports and activities of daily living (ADLs) increased. According to them, the improvement in functionality favors the feeling of freedom and independence: “When I put on my prosthesis, it represented liberation and brought my independence back so that I can do my things like before, like work, play sports” (11, 7p - TT). “It represents my freedom to be able to do my things normally in daily life without depending on anyone, brought me back to being active” (12, 15p - TT).

Most participants emphasized the feelings of freedom and independence that the prosthesis provided, but there was one participant who could not express what it meant for him: “I don’t really think about it. I just live my life and that’s it” (4, 3p - TT).

• It means everything to me.

When asked about what the orthopedic prosthesis represented, users reported that their devices meant everything, going beyond being just equipment that assists in the reconstruction of body image, but also of identity: “It represents everything! With it, I can do everything, right? I only depend on it and on myself, that’s why it represents everything!” (8, 16p - TT).“EVERYTHING! Because with it, I do everything, work, play soccer, swim (I go into the sea, the river)… I do anything, that’s why it represents everything!” (13, 24p - TT).

For individuals with amputations, using orthopedic prostheses can evoke a range of emotions related to self-esteem and acceptance of their new physical condition. These emotions are crucial in the process of reconstructing the amputee’s identity, as they may struggle to recognize themselves after the amputation. Along with these emotions, the users frequently shared their dissatisfaction with using orthopedic prostheses, as well as the way others perceive them as prosthesis users:

• Feelings regarding the use of prosthesis.

In addition to the functional benefits already mentioned, during the interviews, participants pointed out the emotional benefits from using the prosthesis: “It’s almost like being normal again! I see myself as normal again” (6, 4p - TT). “It increases my self-esteem, because before I didn’t like myself as much” (14, 3p – TT).

However, two interviewees expressed feelings of sadness and shame about using the prosthesis: “When I see my prostheses, I feel sad for having lost my legs” (7, 3p – TT). “I only wear long pants, so my prosthesis doesn’t show. I don’t like to show it to anyone because I’m ashamed of it” (8, 16p – TT).

• Difficulties in the daily life of users.

The interviewees expressed difficulties in their daily lives regarding the use of the prosthesis, including adapting to the device and facing limitations in its use: “The amputee still experiences some limitations, such as walking for a long time or going somewhere far away. At least I get very tired” (14, 3p – TT). “There’s a period of pain you have to endure when learning to walk with a prosthesis” (10, 4p – TF).

• The gaze of others.

The interviewees highlighted the issue of how others perceive them as prosthesis users. Despite the availability of advanced technology and information, there still exists prejudice and stigma toward people with disabilities: “I’m an athlete and I do everything on my own, yet many people say, ‘oh, how sad, you don’t have a leg.’ […] Non-disabled people tend to see disabled individuals as pitiful” (1, 24p – TT). “There is still a lot of prejudice, people look at us strangely, you know? Despite my active lifestyle, participating in dancing and sports, I still receive different looks because of my prosthesis” (13, 24p – TT). “When people don’t know you, they usually give you a strange look and often feel sorry for you for using a prosthesis. […] Some people have difficulty seeing past the disability and forget that we are all human beings” (3, 20p – TF).

One report highlights the lack of information that society, in general, has regarding individuals who have undergone amputation: “After a while, I realized that it wasn’t pity, but rather, in my opinion, a lack of information mixed with a bit of ignorance from these people, because they don’t know that a person with a prosthetic can have a normal life like any other person” (2, 5p – TT).

The lack of knowledge in society about different disabilities is a factor that often limits the participation of people with disabilities in the social contexts in which they move, as they may be stereotyped as belonging to a special group of individuals and judged as unfit for work and leisure based on preconceived notions.

This study provides new insights into the (re)construction of body image and identity among Brazilian individuals using orthopedic prostheses, from a phenomenological perspective. It explores participants’ lived experiences, emphasizing how the prosthesis evolves from a tool for mobility to an integral part of their sense of self and identity.

To enhance the trustworthiness of this qualitative study, several procedures were implemented during its execution (Rose and Johnson, 2020). Data collection was completed within a short timeframe to minimize potential inconsistencies in the information gathered. Throughout this phase, three researchers were present to create a supportive environment, allowing participants to express their views, ask questions or withdraw from the study if they chose. The research team consisted of three health professionals – two occupational therapists and one physiotherapist – each with experience in qualitative research.

For the transcription of the interviews, one researcher was responsible for transcribing the data, while the other two reviewed the transcripts to ensure accuracy and eliminate personal biases (Sundler et al., 2019). To further ensure the reliability of the analysis, participants received a summary of the results via email and had the opportunity to add or modify any information they felt did not accurately reflect their views. No changes to the results were requested.

The data collection methodology was thoroughly detailed, ensuring the integrity of the results (Creswell et al., 2007). Regular meetings were held between the researchers and the study coordinator to discuss methods, clarify uncertainties and reaffirm the study’s primary objectives (Shenton, 2013). At the conclusion of data collection, the researchers confirmed that the data were rich and comprehensive enough to provide a full understanding of the phenomenon under investigation.

The three researchers conducted a thorough reading of the transcripts, explored the material extensively and performed the themes organization after multiple face-to-face meetings to discuss and finalize the superordinate themes (Braun and Clarke, 2006).

Based on the perceptions of the interviewees, orthopedic prostheses play a significant role in reconstructing body image and identity by replacing lost limbs. The interviewees reported that orthopedic prostheses are highly valued because they help reconfigure the altered body image and integrate into the body as a natural component, directly contributing to their sense of identity.

The study identified different aspects, such as the perception of the prosthesis as part of their bodies, its benefits and significance. For the interviewees, prostheses became an extension of their bodies, providing them with the perception that it is part of their body. A study conducted by Wald and Álvaro (Wald and Alvaro, 2004) on the psychological factors faced by individuals who underwent traumatic amputation found that prostheses are essential for reconstructing body image and are perceived as a natural part of the body. Conversely, Gallagher and Malcolm (Gallagher and MacLachlan, 2000) employed focus group methodology to capture the perspectives of young adults who had undergone lower limb amputations. The outcomes revealed that participants lamented the loss of a visible part of their body and functionality, along with the adverse effects of amputation on their lifestyle and body image. They also emphasized that, despite using a prosthesis daily, it never truly replaces the limb.

Regarding what the prosthesis provides for its users, they reported physical benefits related to functionality, with the return of functional capacity being pointed out as a relevant factor. An individual’s functional capacity can be understood as the ability to perform various everyday activities using the physical and cognitive functions of the body and is also directly associated with independence during their execution (Chao et al., 2022). An individual who undergoes amputation has their functional capacity altered, becoming dependent, even if only for a period. Bekrater-Bodmann (Kuhlthau et al., 2016), in his study involving a sample of 118 lower limb amputees, demonstrated that prosthesis embodiment, which is the integration of a prosthesis into one’s body image (Tomita et al., 2020), was significantly and positively associated with functional prosthesis satisfaction beyond esthetics, as they perceived the prosthesis as a means of restoring lost functionality. Although functionality was prominently highlighted, participants also mentioned their feelings, particularly the sense of freedom. Schaffalitzky et al. (Gillette and Geller, 2017) found that, for service providers, independence is primarily viewed in terms of functional independence. In contrast, for users, independence is more closely associated with psychological outcomes, reflecting feelings of self-efficacy and self-esteem. Therefore, effective collaboration within a multidisciplinary team is crucial, with the occupational therapist playing a key role in understanding and addressing the patient’s functional expectations. This support helps the patient align their expectations with the reality of functional outcomes, both with and without a prosthesis, in terms of mobility and daily activities. Furthermore, by addressing the patient’s vocational and personal interests related to amputation, the occupational therapist has a significant impact on the patient’s emotional well-being, ensuring a more comprehensive approach to their rehabilitation (Houghton, 2017; McLean and Gilder, 2016; Muir and Smith, 2018). These findings underscore the significance of psychological factors in the process of integrating a prosthesis into the amputee’s body representation, which, in itself, remains a pivotal element linked to prosthesis satisfaction.

As for the meaning of prostheses for their users, according to reports, they become fundamental devices for the reconstruction of body image and identity. Vaz et al. (Khamis and Naser, 2016) who characterized a sample of lower limb amputees psychosocially, stated that the regaining of lost movement through prosthetics provides an increase in functionality, self-esteem, self-confidence and hope, especially in terms of continuing projects planned prior to amputation.

The findings of this study indicate a significant relationship between the stage of the rehabilitation process and the perception of one’s prosthesis. Our analysis reveals that individuals who have used a prosthesis for less than 3 years exhibit a more limited emotional connection with the prosthesis compared to those who have used it for longer periods. Specifically, those who have been using a prosthesis for over 5 years often regard the device as an integral part of themselves, reflecting a deeper sense of embodiment and integration.

The results align with Benavent et al. (Singh et al., 2020), who emphasize that the reintegration of amputees into their bodies occurs in stages, involving the acceptance of physical loss and subsequent reconstruction of self-concept based on the new body schema. The concept of a hybrid body, formed by the prosthesis, plays a crucial role in reestablishing the amputee’s relationship with themselves and society, representing a reconfiguration of their altered physical form (Miele and Moore, 2022). Ostler et al. (Evans and Chitty, 2020) found that initial perceptions of the prosthesis as merely a replacement for the lost limb, essential for regaining normalcy, evolve as individuals progress through the rehabilitation stages. The extended duration required for rehabilitation – including stages of denial, adaptation and acceptance – significantly influences how individuals perceive their prosthesis as part of their body (Miele and Moore, 2022).

Similarly, Chini and Boemer (Schmitt et al., 2021) found a disconnection between the user and the prosthesis upon hospital discharge following amputation surgery and early prosthetic fitting in 13 participants. This finding suggests that in the early stages of rehabilitation, prostheses may still be viewed as a replacement for the missing limb rather than an integral part of the body. This indicates that achieving full integration of the prosthesis into one’s body image is a gradual process that evolves over time.

These findings are consistent with McDonnell (Montano et al., 2021), McDonnell et al. (Garrison et al., 2020) and Fraser (Wilkins and Haigh, 2020), who observed that long-term use of prostheses leads to sensory and motor adaptation, allowing users to perceive the prosthesis as an extension of themselves. The evidence suggests that the integration of the prosthesis into one’s body image is a dynamic process that evolves with time, supporting the observed correlation between the duration of prosthesis use and the depth of emotional connection.

This indicates that, in the early stages of rehabilitation, prostheses may still be perceived as a replacement for the missing limb rather than an integral part of the body. Achieving a full integration of the prosthesis into one’s body image is a gradual process that evolves over time.

Regarding considerations about the use of the prosthesis, the interviewees expressed their feelings and difficulties related to its use. In terms of feelings toward the use of the prosthesis, in addition to the physical and functional benefits already mentioned, the interviewees also reported experiencing emotional benefits such as a sense of normalcy and improvement in self-esteem and self-acceptance. It is worth noting, however, that two interviewees expressed dissatisfaction with the prostheses, including feelings of sadness and shame associated with their use.

While the literature suggests that prostheses are often considered essential by a significant portion of their users for reclaiming a life closer to what it was before amputation, for some, they can be perceived as sources of difficulty, particularly in terms of bodily adaptation, with complications such as pain, wounds and handling difficulties being common (Schmitt et al., 2021). In contrast, Ostler et al. (Tidy and Gullett, 2019) conducted a qualitative study and interviewed six men and two women who had undergone limb amputations. Unlike the findings of Chini and Boemer (Schmitt et al., 2021), the participants emphasized the significance of maintaining a positive attitude throughout the rehabilitation process. They recognized that failing to uphold this attitude could lead to detrimental consequences.

Regarding the difficulties faced by users in their daily lives with the use of the prosthesis, two interviewees mentioned aspects such as difficulty in adapting to the device and functional mobility. In the study by Desmond et al. (Azzabi and Ghaffari, 2021), which investigated the satisfaction of individuals with transtibial amputation regarding their prostheses, it was found that pain is the main cause of dissatisfaction as it hinders adaptation and restricts the performance of everyday activities. Similarly, Littman et al. (Cribb and Roach, 2019), who interviewed 27 male veterans with lower limb amputations to understand barriers and facilitators in physical activity, identified that poorly fitted prostheses led to injury, pain, concerns about balance and fear of falling. As a result, they began to avoid uneven surfaces, stairs and hills, which are considered barriers to functional mobility in the community, thus reducing opportunities for engaging in physical activities. Occupational therapists play an important role in assessing the home and community environment, and providing assistive devices, equipment modifications and environmental adaptations, which is essential for the individual’s rehabilitation progress and helps minimize the negative impacts of activity limitations and participation restrictions (Connolly and MacLachlan, 2021). This study also found that even in today’s society, there is still a gaze from others that carries prejudices and stigmas associated with the amputee. The study conducted by Gallagher and Maclanchlan (Gallagher and MacLachlan, 2000) with 14 participants investigated the factors considered important in adjusting to amputation and the use of prosthetics from the perspective of the amputee. It states that the altered body image remains a source of social discomfort for amputees, as the focus of others’ gaze often first falls on the absence of their limbs before turning to the individual themselves, as highlighted by this study. In this context, Abouammoh et al. (Carr et al., 2020) observed that emotional challenges can hinder functional recovery and the rehabilitation process itself. Among these challenges, depression emerges as the most prevalent response, exerting a detrimental influence on both psychological and physical adaptation. Cruz Silva et al. (Panagiotopoulou and Garanis, 2022) identified that social support can be viewed as a safeguarding element and is linked to improved mental well-being. It prevents negative outcomes and has shown a positive correlation with resilience.

In this study, the data from the 16 participants provided a profound and detailed understanding of the phenomenon. Our phenomenological analysis thoroughly explored the lived experiences of prosthesis users. By emphasizing the qualitative depth of the sample, we believe our findings offer valuable insights into the evolving relationship between prosthesis use and body image. While future research could benefit from incorporating additional perspectives, our study highlights the adequacy of the sample in capturing the essence of this complex phenomenon.

This study explored the (re)construction of body image and identity among Brazilian individuals using orthopedic prostheses from a phenomenological perspective. The findings reveal that prostheses play a significant role in reshaping both body image and personal identity. Participants highlighted how prostheses help restore a sense of wholeness, increasing independence and social participation. While some participants view the prosthesis as an integral part of their body, others still see it as a mere substitute for the missing limb. Notably, longer prosthesis use (over five years) was associated with a stronger sense of embodiment. The study also identified both functional and emotional benefits of prosthesis use, enhancing self-esteem and normalcy. However, challenges such as pain and social stigma persist, underscoring the complexities of adapting to prosthesis use. Despite societal stigmas, prostheses contribute to greater social integration, enabling users to embrace a hybrid body and assume multiple identities that reflect who they are in various social contexts. Overall, this research offers valuable insights into how prostheses influence identity reconstruction. Further studies could expand on these findings, exploring a wider range of experiences and perspectives.

Funding: The authors disclosed that they received no financial support for the research, authorship and/or publication of this article.

Declaration of conflicting interest: The authors disclosed no potential conflicts of interest with respect to the research, authorship and or publication of this article.