Comparison and Application Explanation of Bone Harvesting Instruments

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*Classification of Bone Graft Materials

*Characteristics and Functions of Autogenous Bone Grafts

*When to Use Autogenous Bone Grafts

*Which Bone Harvesting Technique is More Suitable?

*Which Instrumentation is More Effective?

In our previous evaluations, we assessed different types of autogenous bone harvesting instruments, organizing them by category. However, the ultimate outcome yielded bone chips (bone granules).

Apart from the instruments we showcased, bone granules can also be directly collected using an ultrasonic bone knife or a bone collector (bone paste or bone powder). However, due to limited research evidence regarding the collection of bone granules with an ultrasonic bone knife and concerns about bacterial contamination with bone collectors [1], we won’t delve into the above two methods at the moment.

Bone graft materials classification

We all know that in oral implantation, bone grafting is required when encountering bone defects or insufficient bone volume. Autogenous bone granules are one type of bone graft material.

Characteristics and Functions of Autogenous Bone Granules

Autogenous bone grafts are considered the gold standard for bone reconstruction. They possess three main characteristics: osteoinductivity, osteoconductivity, and osteogenesis. Autogenous bone grafts include both block grafts and particulate grafts, with particulate grafts being more osteoinductive compared to block grafts.[2]。

Professor Buser’s team has confirmed a fourth characteristic of freshly harvested cortical bone granules: paracrine function. This means that autogenous bone granules, when soaked in a culture dish containing physiological saline and blood, transform over time into a bone-conditioned medium (BCM). Immersing bone graft materials in this medium facilitates the transfer of osteoinductivity at the molecular level, thereby promoting and accelerating bone formation.[3]。

When to Use Autogenous Bone Granules

Therefore, during guided bone regeneration (GBR) procedures, it is advisable to collect autogenous bone granules as much as possible, especially in cases of extensive horizontal or vertical bone augmentation. The ratio of autogenous bone to allograft or xenograft should ideally be at least 1:1.[4]。

What Bone Harvesting Technique is More Suitable

So, what’s the most suitable way to harvest autogenous bone granules?

Research indicates that the harvesting technique plays a crucial role in the consolidation of grafts. This is often attributed to the impact of the harvesting technique on the viability and activity of bone cells. [5][6]

Compared to samples prepared using bone drills and ultrasonic bone knives, samples collected through bone grinding and bone scraping demonstrate higher cell viability and release rates of molecules affecting bone formation. Additionally, the expression of growth factors such as BMP-2 and vascular endothelial growth factor is significantly higher.[7][8]

Which Instrumentation is More Effective?

Based on the above, we understand that cortical bone harvested through bone grinding and bone scraping is crucial for bone grafting procedures.

So, which instrumentation is the most effective? In clinical practice, apart from considering theoretical and technical aspects, differences in instrumentation types and manufacturers can also lead to variations in clinical efficiency and outcomes.

Through extensive evaluations, we have reached the following conclusions.

Efficiency: Both manual bone scraping knives and motorized bone drills with collection devices tend to be more efficient than those without collection devices because they eliminate the need for manual collection steps.

The efficiency of bone grinding needs to be qualified because before bone grinding, autogenous bone blocks need to be harvested using ring drills, ultrasonic bone knives, or micro saws. The time required for this process depends on the instrumentation and the experience of the surgeon.

Bone Granule Size: Consistent with previous research findings, we also observed that bone granules harvested using manual bone scraping knives and bone grinders tend to be larger, which is more suitable for bone grafting surgeries. However, why are the granules from disc-shaped bone grinders the smallest? From previous videos, it appears that this may be due to the insufficient sharpness of domestically produced disc drills, resulting in bone blocks being ground into powder rather than being cut into small granules within the disc. In contrast, cylindrical bone grinders mill bone blocks into granules resembling rice flour by milling, while simultaneously allowing for the control of granule size by changing the diameter of the central cylinder’s sieve holes.

The bone granules from disc-shaped bone grinders (right half) and imported bone membrane grinders (left half).

Cost: Disposable bone scraping knives are relatively expensive due to their disposable nature, costing in the hundreds. In contrast, cylindrical imported bone grinders are much more expensive than other types of instruments, costing in the thousands.

Disposable bone scraper:

Imported bone grinder：

Technical Sensitivity: Bone scrapers with collection (typically used on the outer oblique line for longer stroke and better force) and bone grinders (for bone harvesting) both require the creation of a second surgical site. Bone scrapers without collection and motorized bone drills, however, can harvest bone around the implantation site within the surgical area.

Recommendation Index (For Reference Only)

Not Recommended: Due to low efficiency, small granule size, and the potential issue of metal powder production, disc-shaped bone grinders are not recommended for use.

Cautiously Recommended: Flat-headed bone scrapers with collection, while inexpensive, may not be very user-friendly due to design issues. Therefore, they are cautiously recommended.

Recommendation Index: Two Stars

Motorized bone drills produce small granules but have relatively lower technical sensitivity. Therefore, they receive a two-star recommendation and can be used for cases requiring small-scale bone grafting.

Recommendation Index: Three Stars

Bone scrapers without collection may have lower efficiency, but if the requirement for autogenous bone granules is not high, such as when only preparing BCM, they are suitable for small-scale GBR. Therefore, they receive a three-star recommendation.

Recommendation Index: Three Stars

Umbrella-shaped bone scrapers have moderate performance in various aspects and can be equipped with interchangeable blade heads. They can be readily available for clinical use, thus receiving a three-star recommendation.

Finally, disposable bone scrapers and cylindrical bone grinders are suitable for various complex bone augmentation surgeries. They are ideal for doctors with clinical experience and economic resources.

Above is merely a summary of the evaluation of different types of bone harvesting instruments. Evaluations may be subject to various factors such as different product batches and testers, thus containing a degree of subjectivity, and do not constitute clinical advice.

Reference:

[1].Sardana, Girish , J. Marshall , and E. P. Diamandis . “Discovery of Candidate Tumor Markers for Prostate Cancer via Proteomic Analysis of Cell Culture–Conditioned Medium.” Clinical Chemistry 53.3(2007):429-437.

[2].Schwartz, Z. , et al. “Ability of Commercial Demineralized Freeze-Dried Bone Allograft to Induce New Bone Formation.” Journal of Periodontology 67.9(1996):918-926.

[3].Monje, Alberto , et al. “Microbial and host‐derived biomarker changes during ligature‐induced and spontaneous peri‐implantitis in the Beagle dog.” Journal of Periodontal Research (2020).

[4].Urban I A , Monje A .Guided Bone Regeneration in Alveolar Bone Reconstruction[J].Surgical Clinics of North America, 2019, 31(2):331-338.DOI:10.1016/j.coms.2019.01.003.

[5].Simon Storgård Jensen, et al. “Evaluation of a novel biphasic calcium phosphate in standardized bone defects. A histologic and histomorphometric study in the mandibles of minipigs.” Clinical Oral Implants Research (2007).

[6].Jensen, Simon Storgord , et al. “Comparative study of biphasic calcium phosphates with different HA/TCP ratios in mandibular bone defects. A long-term histomorphometric study in minipigs.” Key Engineering Materials 361-363(2010):1241-1244.

[7].Bohner, Marc , and  R. J. Miron . “A proposed mechanism for material-induced heterotopic ossification.” Materials Today 22(2018).

[8].Vitale-Brovarone, Chiara , et al. “Biocompatible Glass-Ceramic Materials for Bone Substituition.” Journal of Materials Science Materials in Medicine 19.1(2008):471-478.