Type Of Bone Graft Research Articles

Bioactive Glass as a Bone Substitute for Spinal Fusion in Adolescent Idiopathic Scoliosis

Iliac crest autograft is currently the gold standard material for spinal fusion. However, its use is limited by additional operative time, increased blood loss, and morbidity. Recently, a synthetic osteoconductive bone graft material composed of bioactive glass has been described, with high effectiveness in animal models. Its ability to achieve spinal fusion in human has never been reported. The aim of this study was to compare bioactive glass and iliac crest autograft as bone substitutes in the treatment thoracic adolescent idiopathic scoliosis (AIS). Eighty-eight consecutive patients underwent posterior spinal fusion for progressive thoracic AIS. There were 2 study groups based on the type of bone graft used: iliac crest autograft (n = 40) or bioglass (n = 48). A minimum 2-year follow-up was required. Medical data and radiographs were retrospectively analyzed and compared using unpaired t test and Mann-Whitney U test. Mean follow-up was 40 months in the autograft group and 38 months in the bioglass group. In the autograft group, there were 2 infections (5%) and 3 mechanical failures (7.5%). One infection (2%) and 1 early mechanical failure (2%) occurred in the bioglass group. Loss of correction of the main thoracic curve between immediate postoperative and latest follow-up averaged 15.5% for autograft group and 11% for the bioglass group (P = 0.025). The mean (+/-SD) gain of frontal balance between immediate postoperative latest follow-up was 0.8 (+/-9.3) mm in the autograft group and 8.1 (+/-12) mm for the bioglass group (P = 0.005). Results of this retrospective study suggest that bioglass is as effective as iliac crest graft to achieve fusion and maintain correction in AIS. Less complications were seen in the bioactive glass group, but the difference did not reach statistical significance. Bioactive glass can be proposed in the treatment of AIS, avoiding the morbidity of iliac crest harvesting. However, clinical and radiological outcomes need to be confirmed at long-term follow-up. Level III.

An Immunolocalization Study of Tissue Inhibitors of Metalloproteinase-1 of Bone Graft Healing on Parietal Bone

This immunolocalization study was performed to investigate the temporal and spatial expression of tissue inhibitors of metalloproteinase (TIMP) 1 within endochondral and intramembranous bone grafts during the early stages of healing, in the hope of gaining a better understanding of the mechanisms of bone graft healing, which could influence the choice of bone graft used. Twenty-seven adult New Zealand White rabbits were used as the experimental model. Autogenous bone grafts taken from the cranial bone (intramembranous in origin) and the femur (endochondral in origin) were grafted into skull defects created on either side of the parietal suture. Rabbits were killed on days 1 to 9 postgrafting, and the bone graft alone was harvested for immunolocalization of TIMP-1. In endochondral bone grafts, TIMP-1 was expressed on days 1 to 3, followed by a period of absence until days 8 and 9. Intramembranous bone grafts did not express TIMP-1 until days 6 to 9. The timing and location of TIMP-1 expression coincided with osteogenesis, which indicates a role for TIMP-1 in preserving newly formed bone during the initial stages of graft healing. The differential temporal expression of TIMP-1 in endochondral and intramembranous bone grafts suggests that bone graft type plays an important role in influencing the healing process mediated by the host tissues. The earlier expression of TIMP-1 in endochondral bone grafts could be the reason for delayed vascularization of defects containing these grafts, whereas the delayed expression of TIMP-1 in intramembranous bone grafts could allow earlier vascularization of the intramembranous bone grafts.

Acetabular Cage Survival and Analysis of Factors Related to Failure

The reported results of acetabular cage reconstruction for pelvic deficiency are widely variable. Our primary question was: what is the survivorship of cage reconstruction with a primary end point of cage revision and secondary end points of radiographic loosening and any reoperation? Secondary questions were: which factors predict cage failure, and what is the functional outcome (SF-36, WOMAC, Harris hip score) of this reconstructive method? We reviewed 72 cage reconstructions in 68 patients. Minimum followup was 1.2 years (mean, 5.1 years; range, 1.2-10.7 years). Five-year cage revision-free survivorship was 87.8%. Five-year loosening-free and acetabular reoperation-free survivorships were 80.7% and 81.3%, respectively. No single preoperative factor (age, gender, severity of pelvic defect, degree of heterotopic ossification, difference in limb lengths and centers of rotation) or intraoperative factor (type of bone graft, type of cage, changes in limb length and center of rotation) predicted cage failure. Functional outcomes were 28.9 (SF-36 Physical Component), 52.4 (SF-36 Mental Component), 33.7 (WOMAC), and 44.2 (Harris). We judged these outcomes acceptable for this sometimes challenging problem. Future techniques for treating pelvic deficiency will need to be compared with these and other outcomes in the literature. Level IV, therapeutic study.

Réhabilitation implantaire des fentes labiopalatines : étude rétrospective sur dix ans

Two problems need to be faced during cleft lip and palate surgical treatment to gain a functional and esthetic result: restoration of the maxillary bone defect and the missing lateral incisor tooth, which may be replaced by an implant. The aim of our study was to demonstrate that it is possible to successfully place a dental implant after obtaining adequate bone graft volume. 12 consecutively treated patients were studied, 7 with unilateral and 5 with bilateral clefts, mean age 21.5 years, with an average follow-up of 5.5 years (range: 1-10 years). Various types of autogenous or alogenous bone grafts were performed to provide adequate bone volume for immediate or secondary implant placement. We studied the number of bone grafts needed to reach this target, and the number of implants placed, focusing on lateral incisor tooth replacement. Enough cleft bone volume for the implant was obtained in 9 out of 12 cases (75%). All endosseous implants placed in bone graft were successfully restored, 8 out of them for lateral incisor. Some surgical cases are described. Global improving of cleft lip and palate surgical treatment by implantology is now feasible. Maxillary defect bone grafting, often in several stages, is strictly necessary to place an implant but also to obtain a good cosmetic result in cleft repair. Length, direction, and cervical implant position have to be considered too. Reconstruction of mucosal anatomy also contributes to the end result.

Allogenic bone grafting after cyst enucleation

Cyst of the mandible and maxilla require surgical intervention followed by with or without bone graft. After conventional treatment like enucleation of large cyst, severe facial deformity may occur, and also may produce some other complications. This deformity may be restored and complication may be prevented by use of different types of bone graft. Lyophilized freeze dried bank bone can be used to eliminate the need of a second site operation and reduces the rate of donor site morbidity, minimizes surgical shock, reduces surgical time, shortening healing time and decreases the chances of postoperative infection or complication.

A Stepwise Approach to Revision Total Knee Arthroplasty

Successful revision total knee arthroplasty requires detailed preoperative planning and then a meticulous, stepwise execution of the predetermined plan. Critical factors in revision total knee arthroplasty include the choice of skin incision, type of surgical approach, and component removal without removal of substantial additional bone. The surgeon must then assess the degree of bone loss and ligamentous stability and the position of the current joint line, and then determine the type of bone graft, prosthetic components, and fixation methods required to correct the intraoperative deficiencies. Accurate restoration of flexion-extension gap balance is imperative to ensure long-term successful results.

Bone allografts

Bone allografts can be used in any kind of surgery involving bone from minor defects to major bone loss after tumour resection. This review describes the various types of bone grafts and the current knowledge on bone allografts, from procurement and preparation to implantation. The surgical conditions for optimising the incorporation of bone are outlined, and surgeon expectations from a bone allograft discussed.

Posterolateral fusion using laminectomy bone chips in the treatment of lumbar spondylolisthesis

We retrospectively reviewed the outcome of posterolateral fusion (PLF) in 136 patients with lumbar spondylolisthesis (LS), who had undergone posterior decompression laminectomy with foraminotomy and PLF using laminectomy bone chips as bone graft, with reduction of the slipped vertebra with transpedicle screws, between 1993 and 2003. Diagnosis of LS was confirmed by plain lumbar radiography, with computed tomography (CT) scan or magnetic resonance imaging (MRI) studies performed to confirm an associated condition, such as ruptured disc and spinal stenosis. The outcome of spinal fusion was good with 129 (94.85%) patients attaining solid fusion, while failed fusion was noted in seven (5.15%) patients. None of our patients complained of excessive postoperative wound pain. Additionally, no complications, such as wound infection, were encountered. Proper decortication of the posterior paravertebral gutters with an osteotome and removal of all soft tissues from the laminectomy bone chips are significant factors contributing to the successful outcome of the laminectomy bone chips in PLF. The fusion rate obtained with this type of autogenous bone graft is comparable to that of the iliac bone crest autogenous graft; hence, it is a good substitute for the iliac crest bone autogenous graft in performing PLF in treating lumbar spondylolisthesis.

Arthroscopic Autologous Bone Graft With Arthroscopic Bankart Repair for a Large Bony Defect Lesion Caused by Recurrent Shoulder Dislocation

Many clinicians believe that a large bony defect of the glenoid must be treated with bone grafting when a Bankart procedure is performed. Various types of bone graft, such as open bone graft, Eden-Hybinnette, J-bone graft, coracoid transfer, and Latarjet, have been used. These require open procedures that are difficult to perform arthroscopically. We performed an arthroscopic autologous bone graft and an arthroscopic Bankart repair at the same time to treat a patient with recurrent dislocation of the shoulder joint and a large bony Bankart lesion. We harvested from the lateral site of the acromion 2 bones that were 2.7 mm in cylindrical diameter. We transplanted these bones to the large bony defect of the anteroinferior area of the glenoid and placed anchors between the 2 plugs. During the 30 months since the surgery was performed, the patient has not experienced dislocation or apprehension about the shoulder. A 3-dimensional computed tomography scan showed enlargement of the glenoid surface. Our surgical procedure offers promise for treatment of patients with recurrent dislocation of the shoulder joint and a large bony Bankart lesion because it allows the surgeon to alter the size and the grafted site of the cylindrical bone according to the size of the defect.

PLATE FIXATION OF UNUNITED HUMERAL SHAFT FRACTURES

Background: Delayed union or nonunion of a fracture of the humerus is an infrequent but debilitating complication. Open reduction and internal fixation combined with autologous bone-grafting can result in reliable healing of the fracture; however, there is morbidity associated with the bone-graft donor site. This study was designed to evaluate healing of ununited fractures of the humeral shaft treated by one surgeon at one institution with a strict and consistent surgical protocol but with the use of two different types of bone graft: autologous iliac crest bone graft and demineralized bone matrix. Methods: A consecutive retrospective cohort series was analyzed. From 1992 to 1999, forty-five patients with an aseptic, atrophic delayed union or nonunion of a humeral shaft fracture were treated with open reduction and internal fixation with a plate and autologous iliac crest bone graft. The mean time from the fracture to the surgery was 14.0 months, and the mean duration of follow-up was 32.8 months. From 2000 to 2003, thirty-three patients with the same condition were treated with the same protocol with the exception that demineralized bone matrix was used instead of autologous iliac crest bone graft. The mean time from the fracture to the surgery in that group was 22.6 months, and the mean duration of follow-up was 20.4 months. All patients in both groups were assessed clinically and radiographically. Results: Osseous union was noted clinically and radiographically following the index surgery in 100% of the forty-five patients treated with autologous bone graft and 97% (thirty-two) of the thirty-three patients treated with demineralized bone matrix. The mean time to union was 4.5 months in the group treated with autologous bone graft and 4.2 months in the group treated with demineralized bone matrix. The overall functional outcome did not differ between the groups; however, twenty (44%) of the autologous bone-graft recipients had donor site morbidity, including a prolonged pain in the majority and a superficial infection requiring irrigation and débridement in one patient. Conclusions: Healing of an ununited humeral shaft fracture can be achieved consistently with rigid plate fixation and lag-screw compression augmented with either autologous cancellous bone graft or commercially available demineralized bone matrix. The harvest of the autologous bone graft is frequently associated with complications. Level of Evidence: Therapeutic Level III. See Instructions to Authors for a complete description of levels of evidence.

Plate Fixation of Ununited Humeral Shaft Fractures

Delayed union or nonunion of a fracture of the humerus is an infrequent but debilitating complication. Open reduction and internal fixation combined with autologous bone-grafting can result in reliable healing of the fracture; however, there is morbidity associated with the bone-graft donor site. This study was designed to evaluate healing of ununited fractures of the humeral shaft treated by one surgeon at one institution with a strict and consistent surgical protocol but with the use of two different types of bone graft: autologous iliac crest bone graft and demineralized bone matrix. A consecutive retrospective cohort series was analyzed. From 1992 to 1999, forty-five patients with an aseptic, atrophic delayed union or nonunion of a humeral shaft fracture were treated with open reduction and internal fixation with a plate and autologous iliac crest bone graft. The mean time from the fracture to the surgery was 14.0 months, and the mean duration of follow-up was 32.8 months. From 2000 to 2003, thirty-three patients with the same condition were treated with the same protocol with the exception that demineralized bone matrix was used instead of autologous iliac crest bone graft. The mean time from the fracture to the surgery in that group was 22.6 months, and the mean duration of follow-up was 20.4 months. All patients in both groups were assessed clinically and radiographically. Osseous union was noted clinically and radiographically following the index surgery in 100% of the forty-five patients treated with autologous bone graft and 97% (thirty-two) of the thirty-three patients treated with demineralized bone matrix. The mean time to union was 4.5 months in the group treated with autologous bone graft and 4.2 months in the group treated with demineralized bone matrix. The overall functional outcome did not differ between the groups; however, twenty (44%) of the autologous bone-graft recipients had donor site morbidity, including a prolonged pain in the majority and a superficial infection requiring irrigation and débridement in one patient. Healing of an ununited humeral shaft fracture can be achieved consistently with rigid plate fixation and lag-screw compression augmented with either autologous cancellous bone graft or commercially available demineralized bone matrix. The harvest of the autologous bone graft is frequently associated with complications. Therapeutic Level III. See Instructions to Authors for a complete description of levels of evidence.

THORACOSCOPIC SPINAL FUSION COMPARED WITH POSTERIOR SPINAL FUSION FOR THE TREATMENT OF THORACIC ADOLESCENT IDIOPATHIC SCOLIOSIS

Background: Posterior spinal fusion with segmental instrumentation is the gold standard for the surgical treatment of thoracic adolescent idiopathic scoliosis. More recently, anterior surgery and video-assisted thoracoscopic surgery with spinal instrumentation have become available. The purpose of the present study was to compare the radiographic and clinical outcomes as well as pulmonary function in patients managed with either anterior thoracoscopic or posterior surgery. Methods: Radiographic data, Scoliosis Research Society patient-based outcome questionnaires, pulmonary function, and operative records were reviewed for fifty-one patients undergoing surgical treatment of scoliosis. Data were collected preoperatively, immediately postoperatively, and at the time of the final follow-up. The radiographic parameters that were analyzed included coronal curve correction, the most caudad instrumented vertebra tilt angle correction, coronal balance, and thoracic kyphosis. The operative parameters that were evaluated included the operative time, the estimated blood loss, the blood transfusion rate, the number of levels fused, the type of bone graft used, and the number of intraoperative and postoperative complications. The pulmonary function parameters that were analyzed included vital capacity and peak flow. Results: The thoracoscopic group included twenty-eight patients with a mean age of 14.6 years, and the posterior fusion group included twenty-three patients with a mean age of 14.3 years. The percent correction was 54.5% for the thoracoscopic group and 55.3% for the posterior group. With the numbers available, there were no significant differences between the two groups in terms of kyphosis (p = 0.84), coronal balance (p = 0.70), or tilt angle (p = 0.91) at the time of the final follow-up. The mean number of levels fused was 5.8 in the thoracoscopic group, compared with 9.3 levels in the posterior group (p < 0.0001). The estimated blood loss in the thoracoscopic group was significantly less than that in the posterior fusion group (361 mL compared with 545 mL; p = 0.03), and the transfusion rate in the thoracoscopic group was significantly lower than that in the posterior fusion group (14% compared with 43%; p = 0.01). Operative time in the thoracoscopic group was significantly greater than that in the posterior group (6.0 compared with 3.3 hours, p < 0.0001). There were no intraoperative complications in either group. Vital capacity and peak flow had returned to baseline levels in both groups at the time of the final follow-up. Patients in the thoracoscopic group scored higher than those in the posterior group in terms of the total score (p < 0.0001) and all of the domains (p < 0.01) of the Scoliosis Research Society questionnaire at the time of the final follow-up. Conclusions: Thoracoscopic spinal instrumentation compares favorably with posterior fusion in terms of coronal plane curve correction and balance, sagittal contour, the rate of complications, pulmonary function, and patient-based outcomes. The advantages of the procedure include the need for fewer levels of spinal fusion, less operative blood loss, lower transfusion requirements, and improved cosmesis as a result of small, well-hidden incisions. However, the operative time for the thoracoscopic procedure was nearly twice that for the posterior approach. Additional study is needed to determine the precise role of thoracoscopic spinal instrumentation in the treatment of thoracic adolescent idiopathic scoliosis. Level of Evidence: Therapeutic Level III. See Instructions to Authors for a complete description of levels of evidence.

IN SCAPHOID NON-UNION, DOES THE SOURCE OF GRAFT AFFECT OUTCOME? ILIAC CREST VERSUS DISTAL END OF RADIUS BONE GRAFT

Iliac crest bone grafts are sometimes preferred to other bone grafts for the treatment of non-unions of fractures of the scaphoid as they are claimed to have better osteogenic potential and biomechanical properties. We retrospectively studied a consecutive cohort of 68 symptomatic established scaphoid non-unions treated by bone grafting. An iliac crest graft was used in 44 cases and a distal radius graft in the other 24. The two treatment groups were comparable in terms of location of the fracture, duration of the non-union and the fixation implants used. Overall union was achieved in 45 of the 68 patients (66%) and the union rate was not influenced by the type of bone graft used. Twenty-nine of the 44 treated with iliac crest bone graft (66%) and 16 of the 24 (67%) treated with distal radial graft united. Donor site pain over the iliac crest was present in nine of the 44 patients in this group.

Somatosensory Evoked Potential Monitoring During Anterior Cervical Discectomy and Fusion

A retrospective, multicenter clinical review was conducted. To examine our experience using somatosensory evoked potential (SSEP) monitoring during anterior cervical discectomy and fusion (ACDF) to determine if monitoring of the spinal cord with SSEPs was helpful in identifying reversible causes of neurologic impairment while performing the procedure. Recent studies have strongly supported the use of SSEP monitoring during complicated and upper-cervical spine surgery. The complete medical records of 163 patients who underwent ACDF, and who were monitored with SSEPs during the procedure between 1995 and 2002 were retrospectively reviewed. A single observer who was uninvolved with patient care abstracted these medical records. Demographic data, length of symptoms, workers' compensation status, primary diagnosis, preoperative neurologic status, number of levels fused, bone graft type, implants used, SSEP findings, postoperative neurologic status, complications, and recovery from complications were recorded. Final neurologic status was determined through phone contact with patients or outpatient charts of patients who could not be contacted personally. There were 3 false positive (1.8%) intraoperative SSEP findings in which SSEP changes intraoperatively did not reflect a neurologic deterioration after surgery. There was 1 false negative (0.6%) in which a new neurologic deficit occurred after surgery, despite no change in SSEP amplitudes during the operation. There were 2 true negatives (1.2%) in which SSEP monitoring showed a preexisting neurologic deficit, which did not change during the operation. In no instance were positive SSEP findings clinically useful in alerting the surgeon to potential intraoperative complications. Intraoperative SSEP monitoring is not helpful to the surgeon when performing routine ACDF. Additionally, ACDF is a safe procedure with a low rate of neurologic complications.

Effects of Platelet-rich Plasma on Osteoblast and Osteoclast Number in Canine Mandibular Bone Grafts

Statement of the Problem: Platelet-rich plasma (PRP) was first reported as enhancing autologous mandibular bone grafts in 1998. Since then a number of studies have reported contradictory results on the benefits of PRP used in various types of bone grafts. A recent study from our laboratory reported that the use of PRP in conjunction with autologous mandibular bone grafts in canines resulted in an increased volume of new bone in the graft site at 1 and 2 months, but no difference was seen at 3 and 6 months. This increase was not due to an increase in the rate of bone formation. Additionally, removal of non-viable grafted bone was greater at 1 and 2 months with PRP. We report here on the comparative number of osteoblasts (ob) and osteoclasts (oc) in PRP and non-PRP autologous mandibular bone grafts in canines at 1, 2, 3, and 6 months. Materials and Methods: Twelve adult male dogs had bilateral inferior border marginal resections that measured 2cm x 1cm between the mandibular angle and the mental foramen. Corticocancellous bone harvested from the posterior ilium of each animal was particulated in a bone mill, and equal volumes were placed in each defect. Grafts were stabilized with Vicryl mesh secured to the mandible with two 1.5 x 6mm titanium screws. PRP was produced from 20cc of peripheral blood from each animal. The right side graft in each animal had PRP added while the left side had nothing added. All dogs were maintained on soft diets for 2 weeks postoperatively. Three animals were sacrificed at 1, 2, 3, and 6 months, respectively. The grafts along with adjacent bone were harvested at the time of sacrifice, fixed, dehydrated, and embedded in Spurr’s undecalcified. Two median sections were cut, polished and mounted. Sections were stained with Sanderson’s rapid bone stain and Alizarin red, and examined with a Leitz bright-field microscope. Method of Data Analysis: Twenty fields from each section were analyzed at 100x. The total number of osteoblasts/field were counted. The total number of osteoclasts/field were counted along with the visible number of nuclei in each cell. These numbers were compared for PRP and non-PRP grafts for all times. Results: The comparative numbers of ob and oc for the PRP and non-PRP grafts for all times are expressed as ratios. At 1 month the ratio of ob in the PRP grafts compared to the non-PRP grafts was significantly greater at 1.65:1. The ratio of oc in the PRP grafts compared with the non-PRP grafts is also significantly greater at 2.01:1. At 2 months the ratio of ob in the PRP grafts compared to the non-PRP grafts is 1.02:1, and the ratio of oc in the PRP grafts compared to the non-PRP grafts is 1.21:1. The ratio of ob in the PRP grafts compared to the non-PRP grafts at 3 months is 1:1.1, and the ratio of oc in the PRP grafts compared to the non-PRP grafts is 1.2:1. At 6 months, the ratio of ob in the PRP grafts compared to the non-PRP grafts is 1:1.12, and the ratio of oc in the PRP grafts compared to the non-PRP grafts is 1:1.02. The differences in the number of ob and oc at 2, 3, and 6 months are not statistically significant. The number of oc nuclei seen at the different times, with or without PRP ranged from 3 to 16. There was no statistically significant difference in the number of nuclei in oc with or without PRP at any time. Conclusion: The enhanced healing of autologous bone grafts using PRP that has been reported in previous studies may be due to an increased number of both ob and oc in the graft site. This may be due to increased recruitment and differentiation of ob and oc precursor cells in the PRP graft sites. In the study reported here this effect appears early in the healing process, and is no longer evident after 1 month.

Human Leukocyte Antigen Sensitization after Structural Cortical Allograft Implantations

The incidence and significance of a donor-specific human leukocyte antigen antibody response to massive fresh-frozen human bone allograft implantation is not established. This study was a prospective, multicenter study of a cohort of consecutive patients who self-randomized themselves into two groups based on their alloantibody response to allograft bone transplant. The study hypothesis was that donor-directed antibodies are an independent risk factor influencing incorporation of massive frozen bone allografts. Pretransplant and posttransplant human leukocyte antigen alloantibody analysis was performed and correlated to determine pre-existing and graft-induced antibodies. The surgical outcomes of the two groups of patients were compared to determine the relationship between alloantibody response and bone graft incorporation. Preliminary results revealed that donor-specific human leukocyte antigen sensitization occurred in 17 of 32 (53%) of previously nonsensitized patients. A survival analysis of time to healing based on human leukocyte antigen status showed no evidence of an association between human leukocyte antigen status and time to healing. Longer followup in additional patients will be required to determine if this sensitization is correlated with an alteration in the time to union or with the quality or type of bone graft incorporation. Therapeutic study, Level II. See the Guidelines for Authors for a complete description of levels of evidence.

Alveolar Ridge Augmentation: A Comparative Longitudinal Study Between Calvaria and Iliac Crest Bone Grafts

Insertion of endosseous implants is often difficult because of lack of supporting bone. In the case of severe atrophy of the jaws, a large volume of autogenous bone can be harvested from the iliac crest and calvaria. Both grafts undergo partial resorption with time, but the rate of bone loss has not been fully elucidated. The aim of this study was to evaluate the alveolar bone height gain (ABHG) obtained with iliac crest and calvaria bone grafts. Twenty-five patients had mandibular bone grafts, 32 had maxillary bone grafts, and 11 had both mandibular and maxillary bone grafts. Measures were made on preoperative, postoperative, and follow-up radiographs. A general linear model was used to evaluate the rate of ABHG plotted against months elapsed from the time of the operation to the time of follow-up. General linear model output showed a statistically significant effect for only the type of donor bone graft (P =.004), with a better ABHG for calvaria. The iliac crest bone grafts lost most of the ABHG in the first 6 months, whereas calvaria bone grafts lost ABHG over a greater interval of time. The type of bone graft is the strongest predictor of ABHG, and calvaria bone graft had a higher stability than did iliac bone graft. However, the gap in ABHG between the 2 grafts tended to decrease over time.

The Biology of Bone Grafting

Many approaches are used to repair skeletal defects in reconstructive orthopaedic surgery, and bone grafting is involved in virtually every procedure. The type of bone graft used depends on the clinical scenario and the anticipated final outcome. Autogenous cancellous bone graft, with its osteogenic, osteoinductive, and osteoconductive properties, remains the standard for grafting. However, the high incidence of morbidity during autogenous graft harvest may make the acquisition of grafts from other sources desirable. The clinical applications for each type of bone graft are dictated by the structure and biochemical properties of the graft. An elegant cellular and molecular cascade follows bone transplantation. Bone graft incorporation within the host, whether autogenous or allogeneic, depends on many factors: type of graft (autogenous versus allogeneic, vascular versus nonvascular), site of transplant, quality of transplanted bone and host bone, host bed preparation, preservation techniques, systemic and local disease, and mechanical properties of the graft.

Long‐term stability of autogenous bone grafts following combined application with guided bone regeneration

The aim of the study was to compare the long-term stability of membranous and endochondral autogenous bone grafts with or without combined application of guided bone regeneration (GBR). Twenty-five, male, 6-month old, albino rats were used in the study. The animals were divided into four groups (A5, A11, B5 and B11). Group A5 (control): The inferior border of the mandible was exposed in both sides. At one side of the jaw, a calvarial bone graft (baseline -3 x 4 x 0.64 mm) was placed at the inferior border of the mandible and was fixed with a standardized screw-type titanium microimplant. At the contralateral side, an ischiac bone graft (baseline -3 x 4 x 0.87) was transplanted. The healing period was 5 months. Group A11 (control): The animals were treated in the same manner as in Group A5 with the difference that the healing period was 11 months. Group B5 (test): The animals were treated in the same manner as in Group A5 with the difference that an e-PTFE membrane was adapted over the bone graft on each side of the jaw. Group B11 (test): The animals were treated in the same manner as in Group B5 with the difference that 5 months following transplantation the animals were subjected to a second operation and the membranes were removed. The healing period was 11 months. The animals were killed at 5 (Groups A5 and B5) or at 11 months (Groups A11 and B11) following mandibular augmentation and the jaws were defleshed. The width, the length and the thickness/height of the bone graft were evaluated by means of a stereomicroscope. At 5 months, both types of the membrane-treated bone grafts presented increase in all dimensions compared with baseline. However at 11 months, both types of the membrane-treated bone grafts exhibited a decrease in their dimensions which were similar to the baseline measurements. In the control groups, both types of bone graft presented significant resorption both at 5 and at 11 months with the ischiac bone grafts presenting more resorption in width and length than the calvarial bone grafts. It can be concluded that the long-term volume stability of autogenous endochondral and membranous onlay bone grafts combined with GBR is superior to that of autogenous endochondral and membranous onlay bone grafts alone.

A comparison of two types of free bone grafts as transport discs in segmental distraction for reconstruction of calvarial bone defects: an experimental study

Several investigations over the past few years have shown that the importance of preserving the blood supply of the transport disc during segmental distraction has been overestimated. It was clearly demonstrated that distraction osteogenesis by local bone transportation could be achieved even with free bone grafts. So far, there have been no systematic investigations into how different types of free bone grafts vary in their function and suitability as transport discs in segmental craniofacial distraction. The aim of this study was to develop criteria to aid the clinician in selecting the most suitable free bone graft for distraction purposes. Under general anesthesia, calvarial defects measuring 6 x 5 cm were created in 12 adult black head sheep in order to reconstruct them by segmental distraction using two different types of bone grafts as transport discs. Group 1 (n=6) received autotopical membranous bone of the calvarium as the transport segment, while group 2 (n=6) received heterotopical enchondral material from the iliac crest. Distraction was started postoperatively after 5 days at 0.6 mm/day and continued for 7 weeks. After a further 6 weeks of consolidation, the animals were killed and specimens examined macroscopically, radiographically and histologically. The significantly better quality of bone regenerates of group 1 was clearly influenced by the significantly better stability of the transport disc's connection to the distraction device, the calvaria grafts showing better volume stability and better mechanical resistance during transport than the iliac bone. The influence of both types of bone grafts on the macro- and microstructure of the newly formed bone was clearly evident. The mineralization density of group 2 regenerates was significantly lower than that of group 1 specimens. High mechanical stability of the bone graft is a very important point to consider when selecting a free graft for use as transport disc in local bone transport, especially if transport is necessary over long distances.