Cannulas and scar tissue

Im a tad worried about pumping the rest of my life. I like the convenience of square bolusing and a basal rate that I dont think about much. Plus the fact that I can adjust that basal at a moments notice without having to wait 8-10 hours. So there are some aspects that I really like and depend on. There is however one large issue.

My body really doesn’t like foreign objects. So, cannulas cause irritation unless they are super small. This coupled with insulin delivery into one site over multiple days worries me. As of now I have some scar tissue on the front of my stomach after following the manufactures guidelines (or so I thought).

Some quick background. Ive been pumping I think 8 years now. Used 3 different types of infusion sets, starting with the MM quick set, moving to the silhouette based on MM’s recommendation, then to the new Mio. The 45° silhouettes did not agree with me. Additionally, 9mm cannulas less comfortable than the 6mm ones. My thighs are fairly muscular and so infusion sets there are out.

With the Dexcom (I’m a user of that too), the sensor probe can last me up to 30 days with no irritation but, I think its 26 gauge probe. Which is pretty small. The old MM CGMS was 23 gauge and caused me irritation after 3 days.

So my question is, who’s infusion sets are the thinnest gauge? Really in the long run that is the most important thing. We are all running on limited real estate and in my case it seems I am easy to scar (YDMV). I’m under the impression that the Omnipod is pretty thin, but dont know the size. For me, this will be the determining factor in a new. Plus I’d like to get the info out there for anyone else.

Its going to boil down to a decision of continue pumping or switch over to MDIs again. I’d like to stay on a pump, but honestly am not game to have to take shots in the rear for lack of places to take insulin.


Onesaint: a simple question for me with a reasonably simple answer as I have tried them all too …the BEST for me : MM’s Sure-T 8 mm . I do change every 2 days ; sometimes just a matter of gently pulling the set out and moving it over by 2 inches …I do use IV3000 tape to keep it in place . I consider my legs muscly ( sp?) and do use my legs .What I would like for MM to provide is to have longer tubing av. …these are 23 inches . I have asked them ; will ask again soon .
I also do give a .6 u prime delivery …

Thanks for the reply Nel. The Sure-T looks interesting. Its a 29 gauge cannula from what I can tell and a 2 part system. I guess they didnt want you tugging on the mount with the cannula anymore? =^) Ill ask MM to send me out one to give it a try. Thanks for the recommendation.

Reading through the forums, I recall reading something about scar tissue being caused more from the action of the insulin infusing into the same site over multiple days rather than the physical damage from the cannula insertion. Over the time you’ve been using the pump, have you noticed a difference in scar tissue formation based on differencs in the size of cannulas?

Hi nel, I’ve been using 32" tubing for some months. Much more practical for me than the 23’s.

No, now that you mention it, only in areas of usage. You wouldnt happen to recall where any of that documentation is would you? Id be curious to read it. It may mean Ive been addressing this the wrong way. Thanks FHS.

The chap ( Dave _ ) on TuD , who is not a member anymore ( I miss the guy !) …needs to be credited for me and many others with the changing to Sure-T’s ; for me it was more a matter of kinked cannulas , rather than scar tissue , but who knows .
Yes a 2 part system and I do disconnect , when I shower , which gives me a change too look for bubbles in the tubing .
Darn , I still have not mastered not having bubbles :slight_smile: …another topic !
I just read FHS’s response …would the reason be for infusing larger amounts ? I use an av. of 20 u daily

Before going low carb I was on about 70-100u a day. Now, Im using about 40u. It very well could be the cause In which case the Mios would be find still (although I do like the idea of the 29g of the Sure-T better).
Looks like I;m going to have to start digging on scar tissue more.

Going through 5 sets every 10 days is going to be nuts, if that is the case…

I agree Trudy:… 32 " …for me as well …thanks for letting me know …I live in Canada, this maybe the difference …home work to do !!

No, No, not every 2 days : …you can RE-use the small part going into the flesh at least once more …maybe twice,even three times , I have never tried ?

I am known as a frugal gal , however I do not re-use the needle part often , but I could …don’t tell my Insurance folks , OK ? !t only takes me 30 seconds ( at the most ) to replace this way .

PS Sure -T’s are cheaper ( dearer , correct word ?) in Canada compared to other sets !

I’ve heard the same as FHS, but can’t recall where I read this. Makes sense because MDI causes scar tissue if injections are repeated too much in the same site. It’s not needles or cannulas, though I’m sure they don’t help. The larger the insulin doses, the greater the chance for developing scar tissue.

Np, I think it was in a discussion over in the Dexcom forum onesaint. No real documentation, just a general discussion about how long sensors were lasting.

Thanks you both. As a kid I had build up on the top of my thighs from MDI. That was about 15 years ago. I was under the impression that it would heal as the lumps from insulin went away, although I havent used one of my thighs as a site since. Gee I wish one of my Endos would have pushed me to use another site. =^P

So, I suppose the direction to go in is to see how to repair / stop scar tissue. That and use less insulin. =^) Health permitting mind you. I have cut it back about 35% since going low carb.

Thanks Nel. I suppose its like the Dexcom cannula then. Ill have to play with one to see what it is exactly you mean. I am completely frugal with my D supplies as well. In fact I cant shake the feeling that longer tubing wastes 20u insulin!

Well, I am going to pipe in with a somewhat contrarian message. Dr. B does not like pumps. Why? He believes that having an insertion set in your body 24/7 accelerates the accumulation of scar tissue. He believes that injecting is a quick in-out injury that leaves far less scarring than the trauma of having an insertion set in the same place in your body for days. And scarring does lead to absorption problems.

If you wish to continue pumping you probably should develop a broader rotation of sites even if it means longer tubes, wasted insulin, more insertion sets wasted and even having someone help with insertions. Scarring can be reduced by giving your body time to heal between insertions, but once scarring has developed I’m really not aware of any way to get rid of it. One practice you might start is to use an antibiotic healing cream (like neosporin) on insertion sites after they are removed, that may help the healing process.

ps. I don’t think the amount of insulin has any effect on scarring, I think it is about having a foreign thing in your body.

pps. I like your new avatar, but you really should give up smoking that pipe.

I’ve been pumping for 13 years and have only used silhouettes so I can’t speak to the other styles/types. But … I keep my site for 7 days or more on average and I’ve never had a problem with scaring, infection, absorption, etc. There seems to be enough variety and experience that I honestly doubt you’ll have problems.

bsc, re., pps. - I knew you would. How will I ever sing like Bing if I dont smoke a pipe??

I know Dr. B’s thoughts on this and its one of the instigators of this thought process. That and over time I have seen this issue. Also, a post about how we pay for these technological advances spurred this too. This has caused me concern about the next 40 years of insulin delivery and how I’m going to get it. Lord knows I dont want shots in the butt every day.

I’m really at odds about how the tissue is scarred. I know on my thighs there was build up. It came over time and was a physical lump 2" from my knee to 5" from my hip joint. The scar tissue seems to be slightly firm under the skin with no other signs of issue till you get a cannula in there. Then its a spec of blood and NO absorption.

If found that delivering less insulin really allows my body to accept the cannula for longer (yes, yes, leads to scar tissue). Since going low carb, I have to remind myself to change it every 3 days. The resistance reduction makes the theory of delivery being the scar culprit plausible for me. That and the same slow delivery symptoms as my legs had. This all said, I have previously always subscribed to the theory that it was the foreign object causing the scarring as opposed to the insulin delivery.

I do have scaring around my belly button and have refrained from using it as a site for about a year now. I suppose a shot in the belly would be a good way to check if its an available sight again.

Thanks for the reply DC.

There seems to be enough variety and experience that I honestly doubt you'll have problems

By this do you mean someone will post a solution of some nature?