Histology of ramus cortical bone graft

Hello Dr Misch. Very interesting histology. I can see a lot of "white holes" without cells into the bone. This would be very consistent with the histology presented by me. Am I wrong? This would speak about slow but effective bone incorporation. This is the idea I have about the biological phenomenon of autogenous cortical bone block gratings...
Thank you so much. Dr Meda

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Craig, That is a beautiful histological specimen. I would be curious as to the details relating to placement and biopsy of the cortical graft (adjacent tissues, type of biopsy, orientation ect). I couldn't help but notice the red newly formed bone was present on what appears to be the outer layer of the specimen. Was that portion of the graft adjacent to recipient site connective tissue, bone or both? Thank you so much for your OUTSTANDING CONTRIBUTIONS to our profession not only in this discussion, but through out your distinguished career.Chuck.

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Thanks for the comments Chuck. I thoroughly enjoy your input and reading your comments as well. This histologic specimen is an older case I have used over the years to teach how cortical bone grafts heal. I apologize but I do not recall the details. I just wanted to show a case with the more typical pattern of creeping substitution in contrast to the case Ramon posted.
Regards, Craig

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The “white holes” on the right side are spaces between trabeculae. This was likely an area of the graft that had some “cancellous features (the medial part of the ramus). The smaller “white holes” are haversian canals and will fill over time (the green colored tissue – woven bone lines these cavities). This is at four months – slower remodeling than typically seen with a cancellous graft. I agree with your statement - slow but effective bone incorporation.

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Hi Dr Misch. Sorry for my poor english. I was not speaking about the trabeculae, nor about the haversian canals. I was speaking about the smallest spaces into the pink áreas (non-vital bone) without osteocites. I cannot see it very well but it seems that new osteoblasts are present inside the vital bone (redder áreas).Am I wrong? This is consistent with my histology and of course I absolutely agree with you about the bone remodelling process(slow but effective bone incorporation). Thank you so much for sharing your wisdom about this important issue. My best and happy birthday. Ramón

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Outstanding review of the manner in which autogenous blocks heal and the timing of that healing in relation to the proposed timing of implant placement into the block. Does anyone have access to a histological specimen of these blocks "after" implant placement or loading. The reason I ask is that the bone graft is continuously remodeling and what is the effect of secondary surgical trauma (drilling of implant sites) or Loading (Restoration in Function) have on this process. Buser and Becker separately published a few articles in the 90's in JOMI which described significant resorption of loaded sites that had been treated with GBR?
Great discussion this weekend. Thanks to all. Maurice

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Thanks Maurice. It is great having you contribute and stimulate thoughts on this topic. In 1995 I published on a case where we were able to harvest healed implants from an iliac bone graft after the patient had died (Datillo et al, 1995). The implants essentially looked like implants in native bone. I do recall a Swedish study that used miniature clones of Branemark implants in grafted bone but I would have to do some research. I am not aware of any histology after implant placement or loading in cortical grafts but Mike Pikos does have a case where he harvested a fixation screw within a healed block graft.
Nystrom et al (2009) followed maxillary iliac onlay bone grafts in 44 patients for 9 to 14 years. They used machined implants and had a 92% implant survival. The majority of marginal bone loss occurred in the first year (1.8 mm). At ten years marginal bone loss was only 2.4 mm. All the patients were still wearing their original bridges. Buser et al (2002) followed 66 implants in cortical bone grafts for 5 years and found stable marginal bone levels with no additional resorption. The 5-year implant success rate was 98.3%. Verdugo et al (2011) followed intraoral block bone grafts in 15 patients for an average of 40 months. Computed tomography found 97% of augmented width was maintained after 3.3 years.
It appears that once an autogenous graft has been incorporated that it remodels with new bone and acts like “native” bone. The implant stimulates the surrounding bone and further perpetuates bone remodeling. I have found marginal bone stability even in cases with large vertical augmentations using the iliac crest.

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Thank you dear doctor,
Your result is so useful in early loading protocol.

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Colleagues,

Following is an interesting histological study looking at the interface of Autogenous bone graft with the recipient site published in July 2013, although, it is an animal study, however, it shows that at the interface of both cortical and cancellous autogeic block with a recipient site, there is active bone formation starting at the interface with mineralized matrix ,blood vessels and connective tissue. The interesting part is that the recipient area and graft area were well delimited at 3weeks (corresponding to after 1month in human), while, the interface shows the presence of blood vessels and less connective tissue fulfilling the interface between the graft and recipient area, being this region almost fulfilled by mineralized tissue formation. The interface between recipient area and graft were totally disappear and not evidence in 6 weeks (corresponding to 2 moths in human). and there is no significant difference in the rate of bone formation at the interface between the cortical and the cancellous group even without perforation of the recipient sites. This article is supportive to Craig Misch indication that bone formation at the interface of the Autogenous block and the receipient site is a time dependent well organized process and not anonymous process.
Netto HD, Olate S, Klüppel L, do Carmo AM, Vásquez B, Albergaria-Barbosa J.Histometric analyses of cancellous and cortical interface in autogenous bone grafting.Int J Clin Exp Pathol. 2013 Jul 15;6(8):1532-7. Print 2013

Omar

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Hi, Dr. Misch

Thank you for your great demonstration. I'm Dr.Ye from China.
As we all know, you are the great master upon bone regeneration.
There is one thing bother me a lot.
According to your present case, Can we go to the conclusion that the coronal(trabacular) part of the alveolar bone will be re-corticalized whenever we reduce the cortical portion to accommodate the proper diameter implants when doing the full-arch rehabilitation ?

Your reply will be greatly appreciated.

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