Periodic Reporting for period 2 - XTEND U (Xtend U – An Amputee solution for a life without pain, blisters and infections)
Berichtszeitraum: 2024-01-01 bis 2024-12-31
Xtend U-190163665
Xtend U will improve the microclimate between the socket/liner and the stump besides its function as a normal liner. Among those fitted with a prosthesis, more than 53% complain about thermal discomfort inside the prostheses, regardless of the type of prosthesis or level of amputation.
Xtend U is a prosthetic liner developed to help ventilate the stump while fulfilling the primary role of a liner. The combination of materials enables reducing by half the relative humidity around the stump. This will make a massive difference for users that will get a cooler feeling and reduced risk of chafing, blisters, sores and infections. Xtend U will provide crucial comfort allowing prosthetic users to wear their prosthetics for extended periods of time.
The Xtend U project has progressed considerably during the year since the Grant was approved. The company has focused on the technical solution and fine-tuning it to become a finalized product. The complete assortment and the retrofitability of the product have been defined. A regulatory and commercial strategy for the private label has been developed.
Some technical issues remain to be solved but several alternatives to solve these issues are under development. The work-packages and deliverables that has tight connection to the technical development has thus been delayed but no major issues are noted.
During the progress year, two new possibilities for IP has been identified.
www.lindhextend.com
Xtend U will improve the microclimate between the socket/liner and the stump besides its function as a normal liner. Among those fitted with a prosthesis, more than 53% complain about thermal discomfort inside the prostheses, regardless of the type of prosthesis or level of amputation.
Xtend U is a prosthetic liner developed to help ventilate the stump while fulfilling the primary role of a liner. The combination of materials enables reducing by half the relative humidity around the stump. This will make a massive difference for users that will get a cooler feeling and reduced risk of chafing, blisters, sores and infections. Xtend U will provide crucial comfort allowing prosthetic users to wear their prosthetics for extended periods of time.
The Xtend U project has progressed considerably during the year since the Grant was approved. The company has focused on the technical solution and fine-tuning it to become a finalized product. The complete assortment and the retrofitability of the product have been defined. A regulatory and commercial strategy for the private label has been developed.
Some technical issues remain to be solved but several alternatives to solve these issues are under development. The work-packages and deliverables that has tight connection to the technical development has thus been delayed but no major issues are noted.
During the progress year, two new possibilities for IP has been identified.
www.lindhextend.com
Xtend U
Prototype
There have been an extensive number of prototypes manufactured. Short term testing has been performed in some extent but not enough to freeze the design.
The amount of sweat that the liner should be able to absorb is directly connected to how much superabsorbent yarn the product must contain. Too much superabsorbent will delay the drying time and the superabsorbent is very time consuming to dry.
The absorption capability will be decreased if the material is subjected to pressure which it will be in this type of product. According to the manufacturer can as much as 2/3 of the initial capability be reduced under pressure. The absorption capability under pressure has not been measured so far in the project. However, since we are aware of the capability when not under pressure can we always calculate it from a worst scenario and add a sufficient amount of superabsorbent.
The thickness of the fabric can in some way be controlled by changing the distance between the binding points.
The sequence where the “binding points” are closer to each other gives a thinner fabric. When the distance between the binding points are increased a thicker and more “fluffy” fabric is made. A thicker fabric will have easier to contraction.
We have so far chosen the medium pattern in the prototypes. The amount of superabsorbent yarn can be increased or decreased in each set up.
The purpose of using swell yarn is to increase the thickness of the fabric. If the Xtend U differs from existing liners thickness and doesn’t fit the existing socket (retro-fitting) would mean that many users will not have access to the product or experiences discomfort.
The swell yarn is also used to create cushioning at distal end.
Limitations:
The swell yarn cannot be knitted into the product like the other yarns, it is too thick for the needles and is therefore just added in the centre of the design during the knit process. This means that there is a limit of how much swell yarn that can be added.
Since there are no liners that are knitted on the market, several mechanical tests have been performed to compare strength and flexibility with the existing liner materials, e.g. silicon and copolymer. Abrasion test, ultimate tensile strength test and burst test are some of the tests that have been performed with good results.
Cushioning – the cushioning provided by the swell yarn and fabric at distal end are not sufficient. Tests has been performed with an additional silicone pad and that improves the comfort for the user in a good way. Further development on this part is necessary.
Airtight outer layer – the present outer layer reduces the flexibility (suspension) and makes the donning difficult and time consuming due to high friction (film against film). Friction reducer has been added and tested but with poor result. The difficult donning can cause overflow of fabric at distal end and cause discomfort/blister for the user.
The suspension without the film (just fabric) is good. Further development of the outer layer is required to get an improved function.
Conclusions so far regarding clinical trials-test method development
• Orienting the sensor towards the skin seems to measure the local humidity within the confined space of the sensor housing, which is not relevant since it is excluded from any effects the liner might have on humidity. Also, this small air volume will probably saturate
more quickly.
• Sensor towards liner seems like a better option, but it will, at least occasionally, be associated with confounders when comparing measurements from liners with different occlusive/wicking properties.
• Orienting the sensor sideways, measuring in between liner and skin, seems like a promising approach, measurements are (so far) remarkably consistent.
• There are however indications that the space between liner and skin is so small that unintended seal-off effects occur when measuring sideways, corrupting the results.
• Orienting the sensor towards the skin seems to measure the local humidity within the confined space of the sensor housing, which is not relevant since it is excluded from any effects the liner might have on humidity. Also, this small air volume will probably saturate
more quickly.
• Sensor towards liner seems like a better option, but it will, at least occasionally, be associated with confounders when comparing measurements from liners with different occlusive/wicking properties.
• Orienting the sensor sideways, measuring in between liner and skin, seems like a promising approach, measurements are (so far) remarkably consistent.
• There are however indications that the space between liner and skin is so small that unintended seal-off effects occur when measuring sideways, corrupting the results.
Prototype
There have been an extensive number of prototypes manufactured. Short term testing has been performed in some extent but not enough to freeze the design.
The amount of sweat that the liner should be able to absorb is directly connected to how much superabsorbent yarn the product must contain. Too much superabsorbent will delay the drying time and the superabsorbent is very time consuming to dry.
The absorption capability will be decreased if the material is subjected to pressure which it will be in this type of product. According to the manufacturer can as much as 2/3 of the initial capability be reduced under pressure. The absorption capability under pressure has not been measured so far in the project. However, since we are aware of the capability when not under pressure can we always calculate it from a worst scenario and add a sufficient amount of superabsorbent.
The thickness of the fabric can in some way be controlled by changing the distance between the binding points.
The sequence where the “binding points” are closer to each other gives a thinner fabric. When the distance between the binding points are increased a thicker and more “fluffy” fabric is made. A thicker fabric will have easier to contraction.
We have so far chosen the medium pattern in the prototypes. The amount of superabsorbent yarn can be increased or decreased in each set up.
The purpose of using swell yarn is to increase the thickness of the fabric. If the Xtend U differs from existing liners thickness and doesn’t fit the existing socket (retro-fitting) would mean that many users will not have access to the product or experiences discomfort.
The swell yarn is also used to create cushioning at distal end.
Limitations:
The swell yarn cannot be knitted into the product like the other yarns, it is too thick for the needles and is therefore just added in the centre of the design during the knit process. This means that there is a limit of how much swell yarn that can be added.
Since there are no liners that are knitted on the market, several mechanical tests have been performed to compare strength and flexibility with the existing liner materials, e.g. silicon and copolymer. Abrasion test, ultimate tensile strength test and burst test are some of the tests that have been performed with good results.
Cushioning – the cushioning provided by the swell yarn and fabric at distal end are not sufficient. Tests has been performed with an additional silicone pad and that improves the comfort for the user in a good way. Further development on this part is necessary.
Airtight outer layer – the present outer layer reduces the flexibility (suspension) and makes the donning difficult and time consuming due to high friction (film against film). Friction reducer has been added and tested but with poor result. The difficult donning can cause overflow of fabric at distal end and cause discomfort/blister for the user.
The suspension without the film (just fabric) is good. Further development of the outer layer is required to get an improved function.
Conclusions so far regarding clinical trials-test method development
• Orienting the sensor towards the skin seems to measure the local humidity within the confined space of the sensor housing, which is not relevant since it is excluded from any effects the liner might have on humidity. Also, this small air volume will probably saturate
more quickly.
• Sensor towards liner seems like a better option, but it will, at least occasionally, be associated with confounders when comparing measurements from liners with different occlusive/wicking properties.
• Orienting the sensor sideways, measuring in between liner and skin, seems like a promising approach, measurements are (so far) remarkably consistent.
• There are however indications that the space between liner and skin is so small that unintended seal-off effects occur when measuring sideways, corrupting the results.
• Orienting the sensor towards the skin seems to measure the local humidity within the confined space of the sensor housing, which is not relevant since it is excluded from any effects the liner might have on humidity. Also, this small air volume will probably saturate
more quickly.
• Sensor towards liner seems like a better option, but it will, at least occasionally, be associated with confounders when comparing measurements from liners with different occlusive/wicking properties.
• Orienting the sensor sideways, measuring in between liner and skin, seems like a promising approach, measurements are (so far) remarkably consistent.
• There are however indications that the space between liner and skin is so small that unintended seal-off effects occur when measuring sideways, corrupting the results.
In this state of the project it´s not applicable yet.