' mesotherapy ' is a non - surgical , minimally invasive method of drug delivery that consists of multiple intradermal or subcutaneous injections of a mixture of compounds ' melange ' in minute doses .
it has gained disrepute because of inadequate scientific evidence to prove its efficacy . in spite of this
, many new substances such as platelet - rich plasma ( prp ) , peptides , growth factors and collagen are finding their way to enter the field of mesotherapy . since small amounts of material
have to be injected by multiple pricks rapidly over a large area , mesogun is used .
mesogun is a motor - driven equipment that can be used to rapidly deliver the chemicals into the skin and subcutis .
however , most mesoguns are expensive and tend to waste material due to dripping from the needle postulated to be due to rapid withdrawal [ figure 1 ] .
while this may not be significant in financial terms when inexpensive substances are injected , products such as prp or meso solutions for injection which are either expensive or too precious should not be wasted . the cause for dripping
is possibly due to lack of minimal recoil , following the injection by the motor - driven plunger . on searching the web
, we found a syringe with a spring attached to the piston which would provide the recoil needed to prevent dripping .
since these syringes are not freely available , we modified the available disposable syringe to rapidly deliver small quantity of material into the skin , similar to a mesogun .
a 5 ml syringe or an insulin syringe is taken and the piston is removed from the body and a spring which is sterilised using ethylene oxide is inserted onto the piston which is inserted back into the body of the syringe [ figure 2 ] . the material to be injected
is drawn into the syringe and the regular needle is replaced with the meso needle .
the specifics of the spring provided for the purpose of duplication and standardisation used are as follows : wastage of injectable material from mesogun spring - loaded 5 cc syringes length  37 mm , thickness  1.21 mm , pitch 
4 mm , outer diameter  15 mm , inner diameter  12.6 mm , spring constant ( k ) = 1300 n / m . length  71.30 mm , thickness 
0.75 mm , spring outer diameter  5.7 mm , spring inner diameter  4.58 mm , spring constant ( k ) = 890 n / m . spring constant ( k ) is calculated as follows : the spring constant of a spring represents the force required to deform it by a certain amount . as most springs obey hooke 's law , the spring constant k is treated as a constant characteristic operational parameter for the spring . in the case of helical coiled springs ,
it represents the force required to extend ( or compress ) the spring by a certain length .
experimentally , it is measured by fixing it at one end and applying a force ' f ' on the other end , along its axis , causing it to extend by a length x. the spring constant is then calculated by the formula : f is expressed in newton and x is in metres .
small quantities of material can be injected by first piercing the needle into the tissue , pressing the piston using the thumb and removing the thumb which results in the recoil of the piston ; the syringe is withdrawn from the skin , following which the next site is injected [ video 1 ] . before disposal of the syringe , the spring can be removed and retained for reuse after sterilisation .
the approximate cost of the spring - loaded syringe would be 30 inr for the 5 cc syringe and 26 inr for the 1 cc syringe .
thus the modified spring loaded syringe can be an efficient , cost effective method of drug delivery for mesotherapy and intralesional injections .
length  37 mm , thickness  1.21 mm , pitch  4 mm , outer diameter  15 mm , inner diameter  12.6 mm , spring constant ( k ) = 1300 n / m .
length  71.30 mm , thickness  0.75 mm , spring outer diameter  5.7 mm , spring inner diameter  4.58 mm , spring constant ( k ) = 890 n / m . spring constant ( k ) is calculated as follows : the spring constant of a spring represents the force required to deform it by a certain amount . as most springs obey hooke 's law , the spring constant k is treated as a constant characteristic operational parameter for the spring . in the case of helical coiled springs , it represents the force required to extend ( or compress ) the spring by a certain length .
experimentally , it is measured by fixing it at one end and applying a force ' f ' on the other end , along its axis , causing it to extend by a length x. the spring constant is then calculated by the formula : f is expressed in newton and x is in metres .
small quantities of material can be injected by first piercing the needle into the tissue , pressing the piston using the thumb and removing the thumb which results in the recoil of the piston ; the syringe is withdrawn from the skin , following which the next site is injected [ video 1 ] . before disposal of the syringe , the spring can be removed and retained for reuse after sterilisation .
the approximate cost of the spring - loaded syringe would be 30 inr for the 5 cc syringe and 26 inr for the 1 cc syringe .
thus the modified spring loaded syringe can be an efficient , cost effective method of drug delivery for mesotherapy and intralesional injections .
 mesotherapy refers to multiple injections of small quantity of the drug over a large area . 
 the mesoguns available are expensive and the motor - driven models tends to waste the expensive material to be injected since the plunger stops after injecting without recoil . 
 we searched for a less expensive device which would inject like the mesogun and still not waste the solution . 
 on searching the web , we identified a spring - loaded syringe . 
 we describe the assembly and use of this inexpensive syringe for delivering multiple injections with minimal wastage . 
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Spring for 5 cc syringe
Spring for insulin syringe
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