Fresh-frozen human bone graft for repair of defect after adenomatoid odontogenic tumour removal

The aim of this paper was report the clinical, radiographic, and histological case of adenomatoid odontogenic tumour (AOT) in adolescent woman as well as present the reconstructive treatment of AOT using fresh-frozen human bone graft with guided bone regeneration. AOT is a benign, noninvasive lesion with slow but progressive growth. Biopsy and microscopic examination confirmed the presence of an AOT. Treatment was conservative and the prognosis was excellent. The patient has been followed-up for without recurrence. The use of fresh-frozen human bone graft can be a safe choice for reconstruction of the bone defects to treat AOT.     

The comparative analysis of homologous fresh frozen bone and autogenous bone graft,associated or not with autogenous bone marrow,in rabbit calvaria: a clinical and histomorphometric study

The aim of this study was to evaluate the potential of fresh frozen homologous and autogenous grafts, associated or not with autogenous bone marrow, to form bone. Sixty titanium cylinders were used, and were fixed to the skulls of 30 rabbits. These cylinders were filled with (A) autogenous bone (AM) autogenous bone associated with the bone marrow (H) fresh frozen homologous bone (HM) fresh frozen homologous bone associated with the bone marrow (M) pure autogenous bone marrow and (C) blood clot. The animals were sacrificed after 02 and 03 months. After clinical evaluation, the samples were stained with hematoxylin, eosin and Mallory Trichrome dyes for optical microscopy analysis and histomorphometric analysis. Experimental groups that received mineralized materials (A, AM, H, HM) showed the best bone formation results, presenting no statistical difference between them (P > 0.05). Groups that did not receive mineralized materials (M and C) showed the worst results (P < 0.05), but the M group showed better results than the C group. Most of the autogenous and homologous bone particles were resorbed and there was a larger amount of residual particles in the homologous graft (H, HM) when compared with the autogenous graft (A, AM; P < 0.05). These findings suggest that fresh frozen homologous grafts produced similar amounts of new bone when compared with the autogenous grafts. However, the amount of residual bone particles was larger in the homogenous groups, which may indicate a slower remodeling process. The homologous fresh frozen bone seems to be a good osteoconductive material. The use of only autogenous bone marrow showed better results when compared to the bood clot. However, this research indicates that association with mineralized materials is required.     

Radioprotection provides functional mechanics but delays healing of irradiated tendon allografts after ACL reconstruction in sheep

Successful protection of tissue properties against ionizing radiation effects could allow its use for terminal sterilization of musculoskeletal allografts. In this study we functionally evaluate Achilles tendon allografts processed with a previously developed radioprotective treatment based on (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide) crosslinking and free radical scavenging using ascorbate and riboflavin, for ovine anterior cruciate ligament reconstruction. Arthroscopic anterior cruciate ligament (ACL) reconstruction was performed using double looped allografts, while comparing radioprotected irradiated and fresh frozen allografts after 12 and 24 weeks post-implantation, and to control irradiated grafts after 12 weeks. Radioprotection was successful at preserving early subfailure mechanical properties comparable to fresh frozen allografts. Twelve week graft stiffness and anterior-tibial (A-T) translation for radioprotected and fresh frozen allografts were comparable at 30 % of native stiffness, and 4.6 and 5 times native A-T translation, respectively. Fresh frozen allograft possessed the greatest 24 week peak load at 840 N and stiffness at 177 N/mm. Histological evidence suggested a delay in tendon to bone healing for radioprotected allografts, which was reflected in mechanical properties. There was no evidence that radioprotective treatment inhibited intra-articular graft healing. This specific radioprotective method cannot be recommended for ACL reconstruction allografts, and data suggest that future efforts to improve allograft sterilization procedures should focus on modifying or eliminating the pre-crosslinking procedure.     

Papillary Carcinoma of a Thyroglossal Duct Cyst in a Patient with Thyroid Hemiagenesis: Effectiveness of Conservative Surgical Treatment

ObjectiveTo describe a case of thyroglossal duct cyst carcinoma that arose in a patient with right thyroid lobe hemiagenesis.MethodsWe present the imaging, physical examination findings, treatment, and clinical course of the study patient.ResultsA 35-year-old woman was evaluated for a neck mass that had been present for 6 months and was slowly growing. She reported a previous diagnosis of right hemithyroid agenesis. The patient’s preoperative workup included ultrasonography of the neck and head and neck T1- and T2-weighted magnetic resonance imaging, which showed right hemithyroid agenesis and a cystic lesion in the median region of the neck below the hyoid bone. Findings from chest x-rays and thyroid function tests were normal. The patient underwent a modified Sistrunk procedure that included removal of the median portion of the hyoid bone. Histologic findings showed a 2.5-cm thyroglossal duct cyst with a 0.6-cm focus of follicular variant of papillary carcinoma with invasion of the cyst wall. Total thyroidectomy was not performed because of the absence of tumoral invasion of the parenchyma around the thyroglossal duct cyst and because the patient was at low risk for aggressive disease. Cervical ultrasonography examinations were performed 6, 12, and 24 months after treatment, and all findings were normal. Presently, the patient is symptom-free after 4 years of follow-up and has no evidence of disease.ConclusionIncidentally discovered, well-differentiated thyroid cancer that is confined to a thyroglossal duct cyst in a patient at low risk for aggressive disease can be adequately treated by a modified Sistrunk procedure that includes the median portion of the hyoid bone. (Endocr Pract. 2008;14:465-469)     

Post-operative infection with fresh frozen allograft: reported outcomes of a hospital-based bone bank over 14 years

Femoral head bone allografts have traditionally been used to provide mechanical stability to areas of bony deficiency, or for its osteoinductive and osteoconductive properties. Concerns have been raised over increased infection rates following the use of fresh-frozen graft tissue. This retrospective study aims to investigate the outcomes of fresh frozen femoral heads kept in a regulated, non-commercial bone bank at a university teaching hospital.The local bone bank database was used to identify released femoral heads during a 14 year study period (September 1999–December 2013) whereby a retrospective review of patient records was undertaken to determine clinical outcome. During the observed study period, 427 femoral heads were released from cold storage. Of these, 270 femoral heads had a mean follow-up of 347 days. 157 femoral heads were excluded due to insufficient follow-up data (n = 132) or discarded due to breaks in the cold chain prior to use (n = 25). Of the 270 included femoral heads, 231 (85.6 %) had no reported complications with good graft incorporation. In the remaining 39 with reported complications, only 5 (2.6 %) developed a postoperative infection. Our findings suggest that the use of fresh frozen allograft does not materially increase the risk of post-operative bacterial infection. Our reported post-operative infection rates are comparable with infection rates of other similar studies on fresh frozen allograft use.     

Cancellous and cortical morselized allograft in revision total hip replacement: A biomechanical study of implant stability

To restore femoral intramedullary bone stock loss in revision surgery of failed total hip arthroplasties, impacted morselized cancellous allograft is recommended. This study investigated the mechanical properties of both impacted cortical (group A) and cancellous (group B) morselized bone graft for reconstruction of femoral bones. Ten matched pairs of fresh frozen human femora were prepared by over-reaming to create a smooth-walled cortical shell. Each pair had one cortical and one cancellous impacted morselized allograft and cement. Stem subsidence was evaluated by a cyclic axial load, which was applied by a servohydraulic test. The stem subsidence was measured for initial subsidence (subsidence at the first 1000 cycles), the total axial subsidence (subsidence at the end of cycles under load) and the final axial subsidence (subsidence after the unloading phase). Torque test was measured by torsional loads through the prosthetic femoral heads. Total axial subsidence was significantly higher in group B (mean: 1.32+/-0.32 mm) compared to group A (mean: 0.94+/-0.26 mm) (P<0.01).There was no significant difference between the two groups in terms of initial subsidence (P=0.09) and final axial subsidence.The mean maximum torque before failure was 39.5+/-22.2 N-m for the cortical morselized allograft and 32.5+/-18.1N-m for cancellous.We concluded that impacted morselized cortical bone graft used for reconstruction of contained femoral bone loss in revision hip arthroplasty, may reduce the stem subsidence. Further animal experimentation for mechanical and histological evaluation of in vivo application is warranted.     

A method for removing the brain and spinal cord as one unit from adult mice and rats

To collect complete rodent spinal cord samples for histological analysis, researchers typically use a method that involves fixation of the carcass, followed by decapitation and removal of the vertebrae and the spinal cord. Researchers then decalcify, process and embed the spinal column in paraffin. When this method is used, the spinal cord retains its natural curvature, which may be undesirable to some investigators. The authors describe a methodology by which the entire spinal cord, with the brain attached, can be removed from a mouse or rat, set against a rigid support material and fixed perfectly straight. This allows for more precise sectioning and simplified histological analysis. Researchers can even create block preparations, each of which contains multiple spinal cord sections, so that they can compare anatomically matched sections. This procedure can also be used to obtain fresh spinal cord samples that are free of bone and can be frozen in optimal cutting temperature medium.     

Long term follow-up of reconstruction with allogeneic mandibular bone crib packed with autogenous particulate cancellous bone marrow

Allogeneic mandibular bone processed by the deep frozen method was used as a biologic crib for mandibular reconstruction. The allogeneic mandible is biocompatible, bioresorbable, of low antigenicity and provides the morphology for symphysis contour, angle of mandible and dental arch form. The particulate cancellous bone marrow (PCBM) contains marked osteogenic potential of hematopoietic marrow, which promotes osteogenesis. The cancellous marrow graft lacks structure and requires a crib to house it during the bone regeneration to the consolidation phase. Fresh frozen mandible was hollowed out for packing with PCBM prior to securing it to the defect by a rigid fixation method. Four cases of large mandibular defects resulting from treatment of benign odontogenic tumors were reconstructed utilizing this technique. All cases showed excellent facial contour and function satisfactorily in mastication and pronunciation. Complete graft incorporation and restoration of the osseous continuities were observed for four to 12 years after the operation. This revised version was published online in July 2006 with corrections to the Cover Date.     

Lyophilized allogeneic bone tissue as an antibiotic carrier

The rising number of primary joint replacements worldwide causes an increase of revision surgery of endoprostheses due bacterial infection. Revision surgery using non-cemented implants seems beneficial for the long-term outcome and the use of antibiotic-impregnated bone grafts might control the infection and give a good support for the implant. In this study we evaluated the release of antibiotics from fresh-frozen and lyophilized allogeneic bone grafts. Lyophilized bone chips and fresh frozen bone chips were mixed with gentamicin sulphate, gentamicin palmitate, vancomycin, calcium carbonate/calcium sulphate impregnated with gentamicin sulphate, and calcium carbonate/calcium sulphate bone substitute material impregnated with vancomycin. The efficacy of each preparation was measured by drug release tests and bacterial susceptibility using B. subtilis, S. aureus and methicillin-resistant Staphylococcus aureus. The release of gentamicin from lyophilized bone was similar to the release rate from fresh frozen bone during all the experimental time. That fact might be related to the similar porosity and microstructure of the bone chips. The release of gentamicin from lyophilized and fresh frozen bone was high in the first and second day, decreasing and keeping a low rate until the end of the second week. Depending on the surgical strategy either polymethylmethacrylate or allogeneic bone are able to deliver sufficient concentrations of gentamicin to achieve bacterial inhibition within two weeks after surgery. In case of uncemented revision of joint replacements allogeneic bone is able to deliver therapeutic doses of gentamicin and peak levels immediately after implantation during a fortnight. The use of lyophilized and fresh frozen bone allografts as antibiotic carriers is recommended for prophylaxis of bone infection.     

Rapid preparation of fresh-frozen undecalcified bone for histological and histochemical analysis

An increasing need to be able to relate hard tissue morphology to its histochemistry, and the lack of an adequate methodology, prompted this investigation of polyvinylpyrrolidones of varying chain length as supporting films for the cryomicrotomy of fresh undecalcified cortical and trabecular bone. We developed a method that parallels histological procedures but is biochemically inert and functions at -25 degrees C. Using an LKB heavy-duty cryomicrotome, large numbers of serial sections suitable for histochemistry, immunocytochemistry, or rapid histology can be prepared with ease. Sections from mouse skull, ox vertebra, and human iliac crest illustrate the versatility of the method, and have been examined for the preservation of general morphology and of histochemical activity of those enzymes most prominent in remodeling. The procedure does not preclude the subsequent application of standard hard-tissue embedding methods to the remaining material. Comparison with plastic-embedded bone shows not only close similarities in the structural preservation of the frozen tissue, making possible histomorphometry, but also shows some interesting staining differences. These include the absence of differentiation of the calcification front with toluidine blue stain in fresh frozen specimens, and the presence in frozen osteoid tissue of specific methylene blue metachromasia missing from plastic preparations.     

Rehydration improves the ductility of dry bone allografts

Processing of bone allografts improves infectious safety and allows storing bone substitutes at room temperature. The aim of this study was to compare mechanical properties of the processed Osteopure? bone with fresh frozen bone. All the samples were pieces from femoral heads retrieved during hip arthroplasty operations. The processing includes chemical decellularization, drying and irradiation with 25 kGy. Three types of samples were tested:

1. 1.
   fresh frozen thawed wet,
    
2. 2.
   dry non-rehydrated graft
    
3. 3.
   dry rehydrated graft.
    

In the 3-point bending test Young’s modulus and stress at break yielded no significant difference among the 3 different sample groups. Rehydrating of the dry graft showed increased ductility in strain at break test compared with the other 2 groups (p = 0.003). In compression tests dry grafts had significantly higher maximum effective stress and apparent maximum deformation compared with the grafts of other groups (p < 0.05). Processed bone has almost similar mechanical properties compared with fresh frozen bone. However, rehydration of processed dry graft increases its ductility. These grafts may tolerate bending forces better before breakage.

     

Calcifying odontogenic cyst--Gorlin's cyst--report of two cases

The authors present two cases of calcifying odontogenic cysts, which were confirmed by histological examination. In the first case the radiographic findings and clinical status did not indicate the presence of a calcifying odontogenic cyst. In the second case, differential diagnosis included COC. The histopathological findings showed that what appeared to be simple cases of bone translucencies was in fact an unusual odontogenic lesion. The two cases point out the possibility of incorrect assessment of deceptively banal cases in daily specialist practice.     

Iliac crest fresh frozen homografts used in pre-prosthetic surgery: a retrospective study

In the case of severe jaw atrophy several options are available to restore the alveolar crest. Aim of the present study was to evaluate the resorption over time of homologous fresh frozen bone used to restore the alveolar ridge. Specifically factors influencing (1) graft survival, (2) type, and (3) degree of bone resorption were evaluated. One hundred and thirteen maxillae and 27 mandibles were grafted. The surgical techniques used were 102 inlay, 27 onlay, and 11 veneer. Measurements were taken on pre-operative, post-operative, and follow-up radiographs. Data were processed by using three statistical methods: Kaplan–Meier algorithm, Cox regression, and curve estimation. As regards graft survival, Cox regression output showed a statistically significant effect only on surgical technique (P = 0.0312) and Kaplan–Meier algorithm demonstrated a worse outcome for veneer surgical technique (Log rank test = 0.0242). The Curve estimation demonstrated an inverse correlation between degree of bone resorption over time, with a progressive decrease. In conclusion FFB is a reliable material for alveolar bone restoration with a predicable average of resorption.     

The Effects of Prolonged Cryopreservation on the Biomechanical Properties of Bone Allografts: A Microbiological, Histological and Mechanical Study

Bone allografting is the most common form of allotransplantation in modern medicine. Bone banking is usually the major part of most tissue banks throughout the world. Several years ago, many standards of bone banking were set empirically, and have never been evaluated. One particular parameter or standard was outdating graft materials after 5 years of storage. This study was conducted to evaluate the effect of prolonged cryopreservation on the biomechanical properties of bone allografts and establish whether graft materials become contaminated during long-term storage.Proximal humeral bone allografts were obtained from the bone bank after 1, 3 and 5 years of –80°C cryopreservation. Samples of each humeral head, i.e., cartilage, subchondral bone and spongy bone were histologically examined for inter- and intra-cellular changes. A three-point mechanical bending test was used on identical pieces of cortical bone to compare fresh and cryopreserved materials. Fresh-retrieved cortical bone using identically-sized segments, served as a control. Cultures were taken from each respective sample to determine contamination or sterility.Results of both the histological and mechanical testing showed that there were no significant, qualitative histological, or quantitative mechanical differences among the samples. All the cultures were negative. Therefore, based on this study's parameters, bone allografts can safely be used after a cryopreservation period of over 5 years and should not be discarded.     

Preparation method and growth factor content of platelet concentrate influence the osteogenic differentiation of bone marrow stromal cells

Background aimsAn extensive debate about the clinical benefits of autologous platelet concentrates used as a treatment option for patients with orthopedic injuries is ongoing. The aim of this study was to determine whether different compositions of platelet concentrates may affect the osteogenic differentiation of bone marrow stromal cells (BMSC).MethodsPure platelet-rich plasma (P-PRP) and leukocyte-PRP (L-PRP) were characterized for platelet and leukocyte content. As an indicative marker of the delivery of growth factors (GFs), the release of basic fibroblast growth factor (bFGF) from platelet gel (PG) was measured at 1, 18, 48 and 72 h and at 7 d. The ability of different PGs to induce proliferation and differentiation of BMSC was evaluated by using bioactivity assays.ResultsThe platelet recovery was significantly higher in L-PRP, either fresh or frozen. PGs derived from L-PRP and P-PRP showed significant differences in terms of bFGF release and biological activity. bFGF release was faster both in fresh and frozen L-PRP preparations. Moreover, L-PRP samples were able to induce a significantly higher proliferation of BMSC compared with P-PRP or PPP samples. Even though all PG preparations allowed the deposition of mineral nodules in BMSC cultures, the mineralization activity correlated significantly with bFGF levels.ConclusionsThe biological activity of platelet concentrates differs according to preparation technique, which affects platelet and leukocyte content and GF availability. Because GF levels are not always optimal in subjects with defective bone healing, composition and bioactivity of PRP should be analyzed to test the reliability and potential effectiveness of the regenerative treatment.     

Sterilization with electron beam irradiation influences the biomechanical properties and the early remodeling of tendon allografts for reconstruction of the anterior cruciate ligament (ACL)

Although allografts for anterior cruciate ligament (ACL) replacement have shown advantages compared to autografts, their use is limited due to the risk of disease transmission and the limitations of available sterilization methods. Gamma sterilization has shown detrimental effects on graft properties at the high doses required for sufficient pathogen inactivation. In our previous in vitro study on human patellar tendon allografts, Electron beam (Ebeam) irradiation showed less detrimental effects compared to gamma sterilization (Hoburg et al. in Am J Sports Med 38(6):1134-1140, 2010). To investigate the biological healing and restoration of the mechanical properties of a 34?kGy Ebeam treated tendon allograft twenty-four sheep underwent ACL replacement with either a 34?kGy Ebeam treated allograft or a non-sterilized fresh frozen allograft. Biomechanical testing of stiffness, ultimate failure load and AP-laxity as well as histological analysis to investigate cell, vessel and myofibroblast-density were performed after 6 and 12?weeks. Native sheep ACL and hamstring tendons (HAT, each n?=?9) served as controls. The results of a previous study analyzing the remodeling of fresh frozen allografts (n?=?12) and autografts (Auto, n?=?18) with the same study design were also included in the analysis. Statistics were performed using Mann-Whitney U test followed by Bonferroni-Holm correction. Results showed significantly decreased biomechanical properties during the early remodeling period in Ebeam treated grafts and this was accompanied with an increased remodeling activity. There was no recovery of biomechanical function from 6 to 12?weeks in this group in contrast to the results observed in fresh frozen allografts and autografts. Therefore, high dose Ebeam irradiation investigated in this paper cannot be recommended for soft tissue allograft sterilization.     

Crushed bone grafts and a collagen membrane are not suitable for enhancing cartilage quality in the regeneration of osteochondral defects--an in vivo study in sheep

Hyaline joint cartilage has only a limited potential for self-repair. Some of the published techniques for osteochondral defect therapy try to improve that potential. In this study, it was hypothesised that one of those surgical techniques, the crushed transplanted bone graft together with a collagen membrane, accelerates significantly the reconstruction of the subchondral bone plate and improves the mechanical and histological quality of repaired cartilage in osteochondral defects compared to an empty control defect. In order to test this hypothesis, defects were created in the left knee of 12 sheep and filled either with autologous crushed bone graft or left empty. The animals were sacrificed after 3 (n = 6) and 6 (n = 6) months. No differences were found either macroscopically or histomorphometrically between the bone graft and empty control defects. The biomechanical as well as the histological results of the bone graft defects were inferior to the control defects with inflammatory processes caused either by bone graft or membrane remnants. Based on the results in this sheep model, the filling of subchondral bone defects with compacted cancellous bone should be carefully reconsidered.     

Evaluation of the effect of GnRH on follicular ovarian cysts in dairy cows using trans-rectal ultrasonography

The objectives of this study were to evaluate ovarian changes in cows with follicular ovarian cysts following treatment with either GnRH or saline. The parameters determined were the intervals from treatment to observation of a CL and from treatment to disappearance of the cyst, and the association between serum concentrations of LH, FSH and the LH/FSH ratio, before and after treatment, with the test intervals. Thirty-nine cows were identified as having follicular cysts. The GnRH treatment induced a significant increase in LH and the LH/FSH ratio. The gonadotropin response was not associated with the intervals from treatment to CL detection or to disappearance of the cyst. Survival curves for the intervals from treatment to CL detection and cyst disappearance indicate that treatment with GnRH or saline did not yield significantly different results for either parameter. The results question the efficacy of treating cystic ovarian disease with GnRH.     

Evaluation of Freeze-Dried Dura Mater Allograft as a Collagen Based Barrier (an experimental animal study)

Freeze-dried dura mater allograft (FDDMA) was evaluated as a cost-effective collagenous barrier using an experimental animal model to determine its biocompatibility and 'cell-occlusivity' potential. The FDDMA was processed at the Civil Hospital Ahmedabad, in accordance with the guidelines provided by the South-Eastern Organ Procurement Foundation, U.S.A. Fifteen Charles Foster rats were selected for a study period of 9 weeks. The 1st set graft procedure was performed in an abdominal pouch and after 1 week bilateral mandibular defects were created. One defect was covered by the FDDMA barrier (2nd set graft procedure) and the other defect served as the control. The post operative autopsy and morphological and histological assessments were carried out at 2 and 4 weeks for the 1st set graft, and 3, 6 and 9 weeks for the 2nd set graft procedure. There was acceptance of the 2nd set graft in a pre-exposed animal and no significant inflammatory response. The processed FDDMA demonstrated optimal 'cell-occlusivity' potential for guided bone regeneration to take place in Charles Foster rats.     

Repair of long-bone pseudoarthrosis with autologous bone marrow mononuclear cells combined with allogenic bone graft

Background aimsLong-bone pseudoarthrosis is a major orthopedic concern because of numerous factors such as difficulty of the treatment, high recurrence, high costs and the devastating effects on the patients' quality of life, which sometimes ends in amputation. Although the “gold standard” for the treatment of this pathology is autologous bone grafting, which has high osteogenic, osteoconductive and osteoinductive properties, this treatment presents some restrictions such as the limited amount of bone that can be taken from the patient and donor site morbidity. Bone marrow mononuclear cells (BM-MNCs) comprise progenitor and stem cells with pro-angiogenic and pro-osteogenic properties. Allogenic cancellous bone graft is a natural and biodegradable osteoconductive and osteoinductive scaffold. Combination of these two components could mimic the advantages of autologous bone grafting while avoiding its main limitations.MethodsLong-bone pseudoarthrosis was treated in seven patients with autologous BM-MNCs from iliac crest combined with frozen allogenic cancellous bone graft obtained from the tissue bank.ResultsAll patients showed complete bone consolidation 5.3 ± 0.9 months (range, 2–9 months) after cell transplantation. Moreover, limb pain disappeared in all of them. The mean follow-up was 35.8 ± 4.6 months after transplantation (range, 24–51 months) without pseudoarthrosis recurrence or pain reappearing.ConclusionsCombination of autologous BM-MNCs and allogenic bone graft could constitute an easy, safe, inexpensive and efficacious attempt to treat long-bone pseudoarthrosis and non-union by reproducing the beneficial properties of autologous bone grafting while restricting its disadvantages.