Optimal handling of fresh cancellous bone graftDifferent peroperative storing techniques evaluated by in vitro osteoblast-like cell metabolism

An Osteotomy Tool That Preserves Bone Viability: Evaluation in Preclinical and Clinical Settings

The main objectives of this work were to assess the efficiency, ease-of-use, and general performance of a novel osseoshaping tool based on first-user clinical experiences and to compare these observations with preclinical data generated in rodents using a miniaturized version of the instrument. All patients selected for the surgery presented challenging clinical conditions in terms of the quality and/or quantity of the available bone. The presented data were collected during the implant placement of 15 implants in 7 patients, and included implant recipient site (bone quality and quantity) and ridge evaluation, intra-operative handling of the novel instrument, and the evaluation of subsequent implant insertion. The instrument was easy to handle and was applied without any complications during the surgical procedure. Its use obviated the need for multiple drills and enabled adequate insertion torque in all cases. This biologically driven innovation in implant site preparation shows improvements in preserving vital anatomical and cellular structures as well as simplifying the surgical protocol with excellent ease-of-use and handling properties.

PRESS and Piezo MicroSurgery (Bony Lid): A Seven Year Evolution in a Residency Program Part 2: PRESS- defined site location

INTRODUCTION

Treatment of a failing endodontic procedure via microsurgical revision presents better outcomes due, in part, to the integration of the Surgical Operating Microscope (SOM) and CBCT into clinical practice. But challenges still remain with respect to the operational locations and the techniques required to address them. Posterior sites, with substantial cortical plate thicknesses and sensitive anatomy, present the dichotomy of visualization versus post-surgical regeneration of bone. The bony lid technique bridges the gap between these two concepts, and the application of Piezosurgery renders a precise and biocompatible osseous incision. The purpose of this paper is to outline, through Case reports, the progression of Piezo-Guided surgery in a resident setting.

METHODS

The first two evolutions of the technique utilized a surgeon-defined method for site location. This third and final evolution utilizes a digital workflow to virtually plan the surgical procedure, integrating STL and DICOM files to create 3-dimensional guides with exacting resection locations, levels, and angles. Export of the virtually planned guide in post-production generates the Precision Endodontic Surgical Stent (PRESS) to accurately define the site location and parameters of the procedure. All surgeries were executed using the Piezosurgical method with increasing levels of guidance and precision throughout the evolution process.

RESULTS

Each step in the technique implementation enabled the resident to assimilate a new technique and skill set while maintaining bone architecture and minimizing volume loss post-operatively. The patient benefits were an increase in intra-operative safety and post-operative comfort. The resident benefits were accelerated regeneration timetables, increase in the confidence level of the resident and number of scheduled posterior surgical procedures.

CONCLUSIONS

The progression from crude on-site measurements to elegant and precise surgical guides enabled the access and manipulations of difficult surgical sites without compromising visibility, post-operative osseous regeneration, or patient comfort.

What Happens on the Back Table? Viability and Osteogenic Potential of Reamed Autogenous Bone Graft as a Function of Time and Temperature-A Pilot Study

OBJECTIVES

To provide guidelines for reamed autogenous bone graft (R-ABG) in nonunion surgery to best manage modifiable intraoperative factors, like storage temperature and time, for optimal graft viability. Our hypothesis was that R-ABG graft will show decreased cell viability as a function of increased time and storage temperature.

METHODS

R-ABG samples were obtained using an RIA system from 10 patients undergoing harvest for the treatment of a nonunion. A 10 cm3 sample of cancellous bone graft was divided into 10 samples. A control sample was processed immediately and analyzed using fluorescence activated cell sorting to determine its cell viability. The remaining samples were stored at 0, 15, and 37°C and processed similarly after 60 and 120 minutes. A paired t test was used to compare the mean change in percent viability.

RESULTS

The mean percent cell viability for the experimental conditions was not significantly different from the initial percent cell viability (P ≥ 0.08). There were no significant differences in the change in mean percentage of viable cells (P ≥ 0.07). After 60 and 120 minutes of storage, there were no significant differences in mean cell viability based on storage temperature (P ≥ 0.53 and P ≥ 0.68, respectively). A power analysis estimated that a sample size of 52 patients would be needed to detect a difference.

CONCLUSIONS

The results of our pilot study indicate that storage conditions may have less effect on cell viability than previously hypothesized. Further research with more patients is needed to confirm these preliminary results.

LEVEL OF EVIDENCE

Level II.

Autologous Bone Grafting in Trauma and Orthopaedic Surgery: An Evidence-Based Narrative Review

Autologous bone grafting is common in trauma and orthopaedic surgery. Both the Reamer Irrigator Aspirator (RIA) and Iliac Crest Bone Graft (ICBG) aim to obtain autologous bone graft. Although the process of harvesting a bone graft is considered simple, complications may occur. This study examined morbidity and pain at the donor site, blood loss, and iatrogenic fractures, comparing RIA and ICBG. The source of the autologous bone graft, the alternative graft sites, and the storage modalities of the harvested bone marrow were also evaluated. In May 2021, PubMed, Embase, Scopus, and Google Scholar were accessed, with no time constraints. RIA may produce greater blood loss, but with less morbidity and complications, making it a potential alternative source of bone grafting.

A Novel Osteotomy Preparation Technique to Preserve Implant Site Viability and Enhance Osteogenesis

The preservation of bone viability at an osteotomy site is a critical variable for subsequent implant osseointegration. Recent biomechanical studies evaluating the consequences of site preparation led us to rethink the design of bone-cutting drills, especially those intended for implant site preparation. We present here a novel drill design that is designed to efficiently cut bone at a very low rotational velocity, obviating the need for irrigation as a coolant. The low-speed cutting produces little heat and, consequently, osteocyte viability is maintained. The lack of irrigation, coupled with the unique design of the cutting flutes, channels into the osteotomy autologous bone chips and osseous coagulum that have inherent osteogenic potential. Collectively, these features result in robust, new bone formation at rates significantly faster than those observed with conventional drilling protocols. These preclinical data have practical implications for the clinical preparation of osteotomies and alveolar bone reconstructive surgeries.

Only prolonged time from abstraction found to affect viable nucleated cell concentrations in vertebral body bone marrow aspirate

BACKGROUND CONTEXT

Vertebral body-derived bone marrow aspirate (BMA, with an appropriate carrier) is a potential alternative to traditional iliac crest bone graft for use in spinal fusion surgery. No studies have looked at the effect of different temporary handling/storage conditions on the osteoprogenitor potential of BMA. This is especially important because aspirate, as with cancellous and/or cortical grafts, may be extracted some time before actual implementation in regular clinical use.

PURPOSE

To characterize factors that affect BMA cell concentration during routine spinal instrumentation, this study examined whether cell counts change significantly between the second pedicle aspirated and the first pedicle harvested at the same vertebral level. This study also aims to examine the optimal perioperative storage conditions for BMA obtained from the vertebral body.

STUDY DESIGN

In vitro concentrations of viable cells were determined in BMA harvested from the first and second pedicles on every vertebral level, and after 1 hour of storage in different perioperative conditions.

PATIENT SAMPLE

BMA was harvested from 28 pedicles from seven patients undergoing lumbar instrumented fusion surgeries.

OUTCOME MEASURES

The outcome measure included viable nucleated cell concentrations in BMA.

METHODS

After obtaining HIC approval from our institution, 28 vertebral marrow aspirates (obtained from seven patients) were evaluated. Based on prior work, 4-mL aspirates from each pedicle were evaluated. BMA was aspirated from both pedicles of two vertebral levels per patient. Samples were divided and placed in different storage conditions to examine the effect of laterality (first versus second pedicle aspirated per level), temperature, media, and time, on nucleated cell counts. No funding was received for this study, and the authors disclose no study specific conflicts of interest.

RESULTS

Cell count was not significantly different between the first or second side aspirated for each vertebral level. Similarly, no significant differences were found for samples after 1 hour of storage at different temperatures (0 °C, room temperature, or 37 °C) or media (none, saline, essential media). Of the conditions examined, time from aspiration was the only variable found to have an impact on nucleated cell counts (p=.003). The viable cell count decreased to less than half by 4 hours.

CONCLUSION

As vertebral BMA is increasingly considered as a bone grafting option, the field would be remiss not to consider factors that could affect cell viability after abstraction and before implementation. We expected a greater effect of perioperative storage conditions than was observed. Although the variables evaluated might show small effects on cell viability in a larger study, this would not be expected to be significant. In the current study, only prolonged time from abstraction could be shown to have a significant effect on cell viability.

Autogenous bone graft: donor sites and techniques

Autogenous cancellous bone graft provides an osteoconductive, osteoinductive, and osteogenic substrate for filling bone voids and augmenting fracture-healing.The iliac crest remains the most frequently used site for bone-graft harvest, but the proximal part of the tibia, distal end of the radius, distal aspect of the tibia, and greater trochanter are alternative donor sites that are particularly useful for bone-grafting in the ipsilateral extremity.The most common complication associated with the harvest of autogenous bone graft is pain at the donor site, with less frequent complications including nerve injury, hematoma, infection, and fracture at the donor site.Induced membranes is a method that uses a temporary polymethylmethacrylate cement spacer to create a bone-graft-friendly environment to facilitate graft incorporation, even in large segmental defects.

Intraoperative cooling of iliac bone graft: an experimental evaluation of cell viability

PURPOSE

A cancellous iliac bone graft is used to treat alveolar clefts. A few hours can exist between graft harvest and placement into the alveolar defect. The purpose of this study was to determine whether intraoperative cooling of bone optimizes viability and to evaluate cellular preservation of cooled graft over time.

PATIENTS AND METHODS

Twelve cancellous iliac bone graft specimens were obtained prospectively from consecutive patients undergoing alveolar cleft repair. Each sample was collected during graft procurement and divided into 3 groups: group 1 (immediate analysis), group 2 (analysis after 2 hours at room temperature), and group 3 (analysis after 2 hours on ice). To generate a viability curve, iliac bone specimens were stored on ice and assayed immediately and hourly for 8 hours. Resazurin, an oxidation-reduction indicator of metabolically active cells, was used to assess cellular viability (normalized relative fluorescence units).

RESULTS

Group 1 (n = 7,370) had more active cells than did group 2 (n = 4,104) or group 3 (n = 5,005; P = .03). Group 3 had greater viability than group 2 (P = .03). Cellular preservation of the cooled graft was 100% at the immediate analysis, 98.4% ± 13.9% at 1 hour, 91.8% ± 9.8% at 2 hours, 83.1% ± 31.8% at 3 hours, 71.8% ± 27.2% at 4 hours, 71.4% ± 16.9% at 5 hours, 69.9% ± 19.0% at 6 hours, 70.0% ± 22.5% at 7 hours, and 66.7% ± 13.3% at 8 hours.

CONCLUSIONS

Storing iliac bone graft on ice rather than at room temperature optimizes cellular viability, with cooled bone demonstrating 22.0% more active cells after 2 hours. Cellular loss of cooled graft plateaued after 4 hours. Clinically, the iliac graft should be maintained on ice until placed into the alveolar cleft.

Effect of different storage media on the regenerative potential of autogenous bone grafts: a histomorphometrical analysis in rabbits

The success of autogenous bone graft is related to the graft cell viability. In bone-grafting procedures, harvested grafts are often maintained in extraoral media while the recipient site is prepared. The aim of this study was to evaluate in vivo the effect of storage media over autogenous bone grafts during the transsurgical time. Two grafts were removed bilaterally from the calvaria of 18 rabbits. One graft was immediately fixed in the mandibular angle (control group), and the other was maintained in air exposure (dry group), 0.9% NaCl solution (saline group), or platelet-poor plasma (PPP group) during 30 minutes and stabilized in the symmetrical location of control grafts. After 28 days, the animals were euthanized and the bone fragments were removed, demineralized, and embedded in paraffin. Histological evaluation was performed under light microscope. Empty lacunae and bone graft area quantification were carried out for the sections. The histomorphometrical analysis revealed reduction of the graft area and increase of empty lacunae in the dry group when compared with control. No significant differences were found in the number of empty lacunae or bone graft area between the saline group and its control and also between the PPP group and its control. The dry group showed more empty lacunae and less graft area than the saline and PPP groups. In accordance with the results, PPP and physiologic solution demonstrated osteocyte preservation and bone graft area maintenance, being satisfactory storage media for autogenous bone grafts during the transsurgical period.

Allograft bone matrix versus synthetic bone graft substitutes

Autologous bone is used very often in the treatment of fresh fractures, delayed unions and non-unions. Alternatives have included allografts and in recent years also demineralized bone matrix. The growing availability of good synthetic bone grafts and their advantages in safety and avoiding donor-site morbidity are the reasons that these products are being used more and more. There are on the market a wide variety of substitutes with different capabilities. Nevertheless autologous bone graft is still considered as the gold standard and will be discussed here in that context. Osteoconductive, osteogenic and osteoinductive products will also be classified and their advantages and disadvantages described.

How to store autologous bone graft perioperatively: an in vitro study

INTRODUCTION

Autologous bone graft is the golden standard for bone grafting, but little is known about the influence of various preservation techniques used during surgery immediately following harvest on the osseous structures and graft vitality. Several studies focussed on the optimal treatment of the bone during harvest and implantation, but only few examined the intraoperative storage conditions on the back table. The aim of our study was to examine the influence of various intraoperative preservation techniques on human cancellous bone at different points to optimize the storage during surgery.

MATERIALS AND METHODS

Cancellous bone was harvested during hip arthroplasty and stored for 2 and 4 h under dry conditions, inside a swab moistened with saline solution or in saline solution, 5% glucose solution or culture medium. After the storage period, the bone was cultured and examined 7 days after the first cells grew out in one of these groups. Following the identification of the cells as osteoblast-like cells, the cultures were analysed by fluorescence staining, cell count and the XTT-test.

RESULTS

Fluorescence staining revealed no avital cells in all groups. Dry storage of the bone led to significantly lower cell metabolism after 2 h compared to saline solution and 5% glucose solution. The same was true after 4 h dry storage compared to the moistened swab, and glucose and culture medium. Cell count was significantly lower after 2 h of dry storage compared to saline solution and culture medium.

CONCLUSIONS

Perioperative storage of cancellous bone under dry conditions should be avoided. The bone graft should be stored in saline or 5% glucose solution or a moistened swab.

Osteoprogenitor viability in cell populations isolated from rat femora is not affected by 24 h storage at 4 degrees C

This study was initiated to determine whether partially dissected bones of rats could be refrigerated for 24 h in saline without losing viability of progenitor cells, specifically osteoprogenitors. This is directly applicable to studies involving bone tissue requiring overnight shipment, for example, studies involving space flown animals, grafting experiments, or transplantation. We evaluated cell populations isolated from the proximal femur of 6-week-old male Fisher 344 rats. Explants from the left femur were prepared and placed into culture immediately following dissection, while the right femur was cleaned, fragmented, and stored in saline at 4 degrees C for 24 h, after which explant cultures were initiated. After 11 days of explant culture, cells were collected from outgrowths, counted, and plated to initiate experiments. Plated cells were grown for either 15 or 21 days. To determine if storage affected the total number of colony forming progenitors, alkaline phosphatase positive colonies, or the number of osteoprogenitors, were counted. There was no significant difference in any of the types of colony forming units examined between cell populations derived from freshly prepared samples or those stored for 24 h, indicating that storage at 4 degrees C of bone tissue for 24 h in saline does not affect the osteogenic potential or the number of osteoprogenitors of the cell populations isolated.