How do rods break?

[PeggyS]

I'm assuming most broken rods are the result of a fall or an accident. Is that true? Are there other reasons rods break? Thanks.

[titaniumed]

Pseudarthrosis. Non-union. Failed fusion.Titanium termites.....(scoliosis forum humor)

http://www.orthospine.com/index.php/home-mainmenu-1/67

http://www.ncbi.nlm.nih.gov/pubmed/19652031

http://www.srs.org/patient_and_famil...darthrosis.htm


This is one of our goals, to fuse.....if not, the constant bending back and forth will break the rod or rods. Like a paperclip, bend back and forth and it will break.

After we fuse, the rods simply hang out, and possibly prevent remodeling over time....People that are fused that have rods removed have to worry about this if extreme unbalanced forces constantly pull on the spine. We know this from the elder scolis that were done with casts or casting method many years ago, before Harrington rods. Pre 1960.

If rods are broken due to a pseudarthrosis, that means that there is movement at that joint, and nothing binds it. The spinal cord runs through there so this is something to think about.

Dr Lenke has found pseudarthrosis in patients 8 years post. For those that fuse, or fuse in a correct manner, the fusion mass becomes stronger in time. For those that don’t, the fusion material can be mushy and soft like cheesecake.

For those just out of the oven, getting into a car accident can be a disaster.......for the first few weeks, its probably best to not get in a car.....

Ed

[titaniumed]

I have Synthes “Pangea” system for my hardware. They provide “Pre-bent” rods with the lordotic and kyphotic bends pre formed. They must be annealing after the bend, its another re-heating process that stress relieves the metal. Metals stress upon bending and each metal is different in this regard. The heat treating and stress relieving information that they use is most likely a secret......They must be providing different bends for each sagittal spine shape. (Again, side view)

This system also is designed so that pedicle screws cannot back out. Due to the design, its impossible with the locking caps.

They also do not recommend cross members for patients with DDD. Degenerative Disc Disease.

Bending any kind of metal will weaken it in any state. Bending it in one direction is one thing, but bending it “back” causes major internal fatigue.

Ed

[jackieg412]

Do you think an imbalance can cause stress on the hardware?. Do you also think that no matter what, the type of spines that scoliosis people have , that it wants to curve?

[titaniumed]

Do you think an imbalance can cause stress on the hardware?. Do you also think that no matter what, the type of spines that scoliosis people have , that it wants to curve?

This seems logical.....the higher the imbalance the more stress.....I take it you are asking about your thoracic with single rods now. But you are fused through that area.....

There are quite a few different types of curves, almost infinite, Lenke classifications and so forth. It would seem that larger curves would involve involve more force. This is a difficult question.

I have posted here in the past a few times now about simply increasing hardware size to help eliminate breakage but they do want some movement......not too much, but some.

Tensile screw pullout forces on the Synthes site run around 800 footpounds. I forget what material was tested, but even so this is a HIGH force.

When you bend over in your immediate recovery, every patient needs to think 800# When they say no bending, they mean it.

I can provide links after more coffee (smiley face)

Ed

[leahdragonfly]

Great posts Ed, you said it all! My rods broke from psuedoarthrosis (failure to fuse) at two adjacent levels. One rod broke at the level of around L3, the other at L4, both at the same time. I felt and heard both rods snap, there was no question in my mind they were both broken. I had an extremely loud "pop" about 3 weeks before that x-rayed ok, but I now believe it was one rod cracking but staying perfectly aligned so the break could not yet be seen on x-ray.

I am a nurse in a cardiac cath lab, and was at work when I had the first big "pop." People standing 6 feet away clearly heard it, and the patient in the room thought it was an electrical breaker being tripped. It was that loud. I wan't doing anything out of the ordinary when that happened, and I had suffered no falls or accidents. Pretty scary stuff…I was doing so well right up to that point. I had one titanium rod and one chromium cobalt rod, a system my surgeon chose for extra strength and stiffness since my spine was extremely unstable. I was his first patient to break the new super-duper chromium cobalt rod. Good news is that Dr Hart got me all fixed up again, and I am doing great these days.

[PeggyS]

Thanks for all the info!

Ed you answered my next question with your links. Good job of anticipating! I tried to do a search, but I didn't know the key word psuedoarthrosis.

Thank you, everyone for your answers.

Scary stuff - I guess we're never really 'out of the woods'. I'm glad I asked the question because I was beginning to feel a little overconfident. One day at a time & appreciate each day!

[jackieg412]

Yes I am fused through the area and the fusion was explored before the 'removal of that left segment. But as soon as the surgeon saw me the first thing he said was I wonder if it is the scoliosis causing the shoulder drop. He took stays and told me that the spine was fine. So it makes you wonder how much the spine wants to move.and with it that alone may cause extreme stress on the rods.

[susancook]

Jackie, I recently broke my titanium rod at T10. Unlike Gayle, I never heard or felt anything. I had many areas in my back that were not fused, probably due to an infection along the hardware by PROPIONBACTERIUM ACNES. It was a slow growing infection. With many areas not fused, there was constant stress to the rod. I asked Dr. Hart what would happen if I did not have the surgery to replace the broken rod and he said, "you will break the other rod".

Susan

[Mojo's Mom]

Do we know if pseudoarthrosis leading to broken rods is less likely with the combined ALIF/PLIF procedure than with PLIF only or TLIF approaches?

[LindaRacine]

Do we know if pseudoarthrosis leading to broken rods is less likely with the combined ALIF/PLIF procedure than with PLIF only or TLIF approaches?

I assume you mean combined ALIF/PSF (posterior spinal fusion) procedure. I don't think I've ever seen a study, but it's relatively rare the 360 circumferential fusions lead to areas of non-union (pseudarthrosis). PLIFs and TLIFs are also circumferential fusions (with access from the patient's back, to the front of the spine. PLIFs and TLIFs always include PSF procedures.

Hope that's not too confusing.

--Linda

[titaniumed]

Stephanie

Excellent question!

There are several ways of climbing Mt Everest. Different routes involve certain challenges and obstacles, and climbers goals are not necessarily the easiest way up.

As scoliosis patients, we don’t want to take the hardest route, but sometimes we have to.

ALIF has good success rates as far as pseudarthrosis. 90-95% It’s the avalanches that you have to worry about.

All the factors need to be weighed out before climbing. It’s the same thing with our surgeries. Our surgeons have this extremely difficult task.

Ed

[LindaRacine]

I'm assuming most broken rods are the result of a fall or an accident. Is that true? Are there other reasons rods break? Thanks.

It looks like no one said anything about falls or accidents. Broken implants from trauma is VERY rare.

--Linda

[leahdragonfly]

Hi, I am one of the unlucky few who has suffered broken rods twice (broke both rods on two separate occasions). Neither time was related to trauma or falls, but to pseudoarthrosis. Apparently I don't fuse well. I wouldn't wish this problem on anyone!

[titaniumed]

Linda, your right!

That’s because we are not even allowed to think about these things....

Car accidents are a disaster.....we had one poster here a few years ago that posted about this but she never followed up with us. Remember? She was in a lot of pain.....

When autonomous cars become popular here shortly, it will be a different story. The problem will be programming the destination on meds. Can you imagine at the hospital, they usually ask who is driving you home. “I have a self driving vehicle here, can you program it so it will take me home?” Please don’t send me to Disneyland, I don’t think I can handle Mickey Mouse right now. (smiley face)

Ed