Pet Perspective/Histology

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Posted on By rocco mele In Bone Grafting

A few weeks ago, I posted a grafting case that became the basis of a discussion on grafting materials and techniques. I found it interesting to see that the histological results of my case were challenged; I was not upset or offended but I needed to know that the techniques and materials that I was using in grafting were getting the histological as well as clinical results that I was seeing. To that end, I submitted my slides to Roy Pool, DVM, Phd and an expert in osteogenic analysis on a histological level. I am presenting Dr Pool’s email as a means to continue our discussion on what treatment modalities are successful and which are not. 
I have learned a lot from my experience on Dental XP. I am posting Dr Pool’s analysis to give a cellular perspective to help further our knowledge. As we all do on this forum.
I welcome any and all comments so that we can all learn from this discussion.

Your histological illustrations of the compact bone graft are of excellent quality.
Back in the early 1970’s when I first ventured into the orthopedic pathology practice in the UCD CVM Pathology Department and began learning about bone nutrition and the use of compact and cancellous bone grafts in fracture repair, I learned that well before my time it was already well understood that whenever a bone specimen was removed from its bed, the osteocytes buried in the bone would die within a few days since their nutrition was dependent upon an intact canalicular-lacunar fluid system. The fluid system was ultimately supplied by a functional adjacent capillary bed that initially nourished the bone lining cells that covered the bone surface and which, in turn, controlled the passage of nutrition and calcium and other ions to and from the buried osteocytes to which they were in contact by tenuous cytoplasmic connections passing through the canalicular-lacunar system.
Since microcirculation within the bone depends upon simple diffusion, there is a limit, perhaps only 3-4 cells deep to the bone lining cells, that osteocytes can be buried from a bone surface. Bone tissue containing osteocytes that are buried too deeply are deprived of nutrition and either go into hibernation or die. But these buried bony elements called interstitial lamellae continue to serve to maintain the mechanical function of the bone in which they are located. They will remain in situ until a bone remodeling unit discovers and removes and replaces them with viable bone while providing a new bone surface from which the newly deposited bone remodeling unit will receive nutrition and participate in calcium homeostasis.
The following is a quote from Chapter 10. Repair and Transplantation of Bone, in The Biochemistry and Physiology of Bone, 2nd ed. Edited by Geoffrey Bourne, Vol III Development and Growth, Academic Press New York, 1971. Pp. 381-383 {Note the relatively ancient date}
“It is therefore, not surprising that when sections of grafts of compact bone that have been in place for a week or more are examined to find the lacunae of the bone of the graft empty or containing pycnotic nuclei; further, no evidence of cellular life is to be found in the Haversian canals within the substance of the graft.”.....”In due course it was shown that for all intents and purposes transplants of cortical bone are transplants of dead bone.”.....”Aside from providing fixation, the function of a transplant of compact bone is to stimulate osteogenesis from its bed which attaches it to its host and to conduct osteogenesis throughout its substance so that it is eventually replaced by new bone from its host.”
What more is there to say about this relatively ancient wisdom!!!!!!
Roy Pool, DVM, PhD
Clinical Professor of Pathology TAMU CVM Osteopathology Service

Equine Block/Histo
Equine Block/Histo

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Autologous Clinical Presentation
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Hi Rocco,
Thanks for presenting the science for what you do. As an observer, I can only know what you tell me. The histology provides validation of your materials and techniques.
Thanks for going the extra mile.



What can I say. Thank you for your support and your "tell it like it is attitude "



Thank you very informative and interesting. It is this knowledge that makes it possible to do what we do in our practices to help people. Clinical experience and knowledge is the key, not a silver bullet.



Thanks for taking the time to comment.

" Clinical experience and knowledge is the key " and hopefully some common sense :)



Hi Rocco, it's a great message and a basic fundamental bone histology . Thanks for sharing. Always Autogenous is not the only answer in bone grafting. It's individual preference, based on their work, results and clinical experience. Your H & E stained slide with bone forming cells is really good. Regards.



I have to agree with that...
I have never operated on a human patient, only myself...

So, I cannot speak to bone grafting, resorption, loading,etc
in people.

I would have to assume its very similar in the animal model.

If not why do we sacrifice all these animals for the sake of inferior results?

Thank you



Dear Rocco,

your contribution to our profession is amazing.
Clinically the bone looks very vital and histology shows what we expected. In human it takes more time.
Interestingly, today on our way back from XP Symposium in NY (great time with dear colleagues) my student Monika Keca and me discussed inter positional equine bone block for vertical ridge augmentation. What occupied us was the question in which % can we expect resorption of coronal cortical bone.
Thank you for this important piece of evidence!
PS There was no time for Pizza in NY:)



You are to kind Thank you

Happy to hear about the great time in NYC and a great meeting. But you missed out on an even better time at Juliana's in Brooklyn :))) Better than Rome...

Also, I have some good information on Equine block for inter positional vertical ridge augmentation. Somewhere

I will find it and get it to you.



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