Bone Graft Donor Site Research Articles

A Musculoskeletal Model of the Equine Forelimb for Determining Surface Stresses and Strains in the Humerus—Part II. Experimental Testing and Model Validation

The first objective of this study was to experimentally determine surface bone strain magnitudes and directions at the donor site for bone grafts, the site predisposed to stress fracture, the medial and cranial aspects of the transverse cross section corresponding to the stress fracture site, and the middle of the diaphysis of the humerus of a simplified in vitro laboratory preparation. The second objective was to determine whether computing strains solely in the direction of the longitudinal axis of the humerus in the mathematical model was inherently limited by comparing the strains measured along the longitudinal axis of the bone to the principal strain magnitudes and directions. The final objective was to determine whether the mathematical model formulated in Part I [Pollock et al., 2008, ASME J. Biomech. Eng., 130, p. 041006] is valid for determining the bone surface strains at the various locations on the humerus where experimentally measured longitudinal strains are comparable to principal strains. Triple rosette strain gauges were applied at four locations circumferentially on each of two cross sections of interest using a simplified in vitro laboratory preparation. The muscles included the biceps brachii muscle in addition to loaded shoulder muscles that were predicted active by the mathematical model. Strains from the middle grid of each rosette, aligned along the longitudinal axis of the humerus, were compared with calculated principal strain magnitudes and directions. The results indicated that calculating strains solely in the direction of the longitudinal axis is appropriate at six of eight locations. At the cranial and medial aspects of the middle of the diaphysis, the average minimum principal strain was not comparable to the average experimental longitudinal strain. Further analysis at the remaining six locations indicated that the mathematical model formulated in Part I predicts strains within +/-2 standard deviations of experimental strains at four of these locations and predicts negligible strains at the remaining two locations, which is consistent with experimental strains. Experimentally determined longitudinal strains at the middle of the diaphysis of the humerus indicate that tensile strains occur at the cranial aspect and compressive strains occur at the caudal aspect while the horse is standing, which is useful for fracture fixation.

A Musculoskeletal Model of the Equine Forelimb for Determining Surface Stresses and Strains in the Humerus—Part I. Mathematical Modeling

Knowledge of the forces that act upon the equine humerus while the horse is standing and the resulting strains experienced by the bone is useful for the prevention and treatment of fractures and for assessing the proximolateral aspect of the bone as a site for obtaining autogenous bone graft material. The first objective was to develop a mathematical model to predict the loads on the proximal half of the humerus created by the surrounding musculature and ground reaction forces while the horse is standing. The second objective was to calculate surface bone stresses and strains at three cross sections on the humerus corresponding to the donor site for bone grafts, a site predisposed to stress fracture, and the middle of the diaphysis. A three-dimensional mathematical model employing optimization techniques and asymmetrical beam analysis was used to calculate shoulder muscle forces and surface strains on the proximal and mid-diaphyseal aspects of the humerus. The active shoulder muscles, which included the supraspinatus, infraspinatus, subscapularis, and short head of the deltoid, produced small forces while the horse is standing; all of which were limited to 4.3% of their corresponding maximum voluntary contraction. As a result, the strains calculated at the proximal cross sections of the humerus were small, with maximum compressive strains of -104microepsilon at the cranial aspect of the bone graft donor cross section. The middle of the diaphysis experienced larger strain magnitudes with compressive strains at the lateral and the caudal aspects and tensile strains at the medial and cranial aspects (-377microepsilon and 258microepsilon maximum values, respectively) while the horse is standing. Small strains at the donor bone graft site do not rule out using this location to harvest bone graft tissue, although strains while rising to a standing position during recovery from anesthesia are unknown. At the site common to stress fractures, small strains imply that the stresses seen by this region while the horse is standing, although applied for long periods of time, are not a cause of fracture in this location. Knowing the specific regions of the middle of the diaphysis of the humerus that experience tensile and compressive strains is valuable in determining optimum placement of internal fixation devices for the treatment of complete fractures.

Single-Level Instrumented Posterolateral Fusion of Lumbar Spine With β-Tricalcium Phosphate Versus Autograft

A prospective, randomized clinical study comparing beta-tricalcium phosphate (beta-TCP) with autograft bone graft with follow-up of 3 years. To determine the efficacy of beta-TCP as a bone graft substitute combined with local autograft obtained from decompression compared with the use of autologous iliac crest bone graft in single-level instrumented posterolateral lumbar fusion. A variety of bone graft substitutes have been used in posterolateral lumbar fusion with different efficacy reported, but no controlled study was conducted on the clinical performance of beta-TCP in instrumented posterolateral lumbar fusion. Sixty-two patients with symptomatic degenerative lumbar spinal stenosis were treated with single-level instrumented posterolateral lumbar fusion. They were randomly assigned to fusion with beta-TCP combined with local bone obtained from the decompression (group A, n = 32) or autogenous iliac crest bone graft plus decompression bone (group B, n = 30). The patients were observed up for 3 years after surgery. The results were assessed clinically and radiographically. There were no significant differences in recovery rate of Japanese Orthopedic Association score and SF-36 score at all time intervals. Successful radiographic fusion was documented in all patients in both treatment groups. All patients in group B, however, complained bone graft donor site pain although significant improvement of pain was observed during the follow-up. Instrumented posterolateral fusion with beta-TCP combined with local autograft results in the same radiographic fusion rates and similar improvement of clinical outcomes and life quality compared with autograft alone. The authors therefore recommend the use of beta-TCP as bone graft substitute for instrumented posterolateral fusion of lumbar spine to eliminate the need of bone grafting harvesting from the ilium.

Mechanical stability of structured bone grafts from the anterior iliac crest

Background The anterior part of the iliac crest is frequently used as a donor site for autogenous bone grafts. Depending on the clinical scenario, the grafts are exposed to compression and shear stresses. Insufficient stability of a bone graft can lead to the collapse of a reconstruction. The object of this study was to quantify the influence of surgery-related parameters like the bony composition (cancellous, unicortical and bicortical), the donor site and the angle of removal on the failure load of the bone plugs (shearing and compression tests). Methods A total of 137 bone cylinders varying in bony composition and in their angles to the trajectories in the anterior iliac crest were taken from 48 human hemipelvises with diamond hollow cutters. The failure load was measured in a standardized manner, each bone plug being subjected to two shear tests and three compression tests. Possible differences between groups were evaluated using analysis of covariance techniques with BMI, bone density and cortical thickness as covariates. The statistical significance level was set to 5% ( P < 0.05), no adjustment for multiple comparisons was done due to the descriptive nature of the study. Findings Bicortical bone plugs were more resistant than unicortical plugs to both compression and shear stress, and both were more stable than cancellous bone plugs ( P < 0.05). On average, the compression failure load was about twice as high as the corresponding failure load with shearing tests: the factor was approximately 1.5 for cancellous, approximately 2 for unicortical and approximately 3 for bicortical bone plugs. We could not find a significant effect of the precise donor site and the angle of removal (parallel or perpendicular to the crista) on the mechanical stability of cancellous bone plugs. Interpretation Surgeons should rather focus on the cancellous or cortical composition of the graft than location of the harvesting site or drilling angle in order to obtain a useful bone plug from the iliac crest.

Experimental application of a biomaterial in bifocal transport osteogenesis for craniofacial reconstruction

Bifocal transport osteogenesis is an alternative technique of callus distraction, in which movement of a transport segment results in the formation of new bone in order to close a continuity defect. The aim of this experimental pilot study was to replace a bone graft by a biomaterial as a transport segment. Critical size defects of the calvaria in four adult sheep were treated with transport segments consisting either of an autogenous free bone graft of the calvaria (n=2) or of the biomaterial (deproteinized bovine cancellous bone; n=2). Latency period was 5 days; the rate of distraction was 1mm per day and was planned for 40 days. The consolidation period was 28 days. Specimens were investigated by conventional radiography, CT-scans and histologically, including immunofluorescence. In both groups, transport osteogenesis resulted in a "de novo" formation of bone, indicating that this biomaterial may contribute successfully to bone formation in bifocal transport osteogenesis. However, volume and thickness of the newly formed bone at the defect site were smaller when using the biomaterial than when using autogenous bone grafts. The application of a biomaterial as transport segments in bifocal transport osteogenesis in cranial critical size defects resulted in the formation of new bone thus excluding bone graft donor site morbidity.

Poster 163: Autogenous Bone Graft Versus Distraction Osteogenesis for Maxillary Augmentation an Histological Analysis

Poster 163: Autogenous Bone Graft Versus Distraction Osteogenesis for Maxillary Augmentation an Histological Analysis

Clinical Application of Resorbable Polymers in Guided Bone Regeneration

AbstractSummary: Guided bone regeneration was shown to be successful in vitro and in vivo using resorbable or nonresorbable materials. Resorbable material has the advantage of progressive substitution by bone. Resorbable polymers of ∝‐hydroxy acids like polylactide or polyglycolide are commonly used for tissue engineering and in guided bone regeneration. In clinical studies, guided bone regeneration was successful in non‐weight bearing bone, e.g. in dental surgery and craniofacial surgery. This paper reports the preliminary result of using resorbable poly(L/DL‐lactide) 80/20% scaffolds in weight bearing bone with infected large segmental defects as well as in small bony defects of hand due to benign tumour, bone graft donor sites and as an adjunct for joint fusion. Resorbable polylactide implants were used in the form of membranes, large 3‐D sponges, chips or as injectable paste. Implants were impregnated with marrow blood to add an osteoinductive component. Long‐term follow up revealed that these implants are promising candidates for bone graft substitutes.

Conversion of the monocortical iliac bone graft to the three-dimensional prism bone graft

The iliac crest is the most common bone graft donor site. However, harvesting of tri or bi-cortical iliac bone graft is associated with some potentially serious complications and cosmetic deformity. We would like to present a case in which we used a new technique converting the mono-cortical iliac graft to the three-dimensional prism bone graft in order to reconstruct an acquired first metatarsal defect and to avoid the potentially serious complication of the iliac crest bone harvest. A six-year-old boy was referred to our institution due to the posttraumatic deformity of his left foot. He had a short big toe and dorsoflexion contracture of first metatarso-phalengeal joint due to the first metatarsus defect and previous skin graft. To reconstruct the bony defect, 4 x 3 cm monocortical bone graft was harvested from the anterior aspect of the ilium by using the peel-off technique. Then, the mono-cortical graft was converted to the prism with the appropriate osteotomies. This custom shaped tri-cortical prism bone graft was placed into the first metatarsal defect. Lateral arm fascia-cutaneous free flap was used for soft tissue reconstruction. The patient was able to walk without support and wear regular shoes and started playing freely with his friends at four months after the reconstruction. This is a single case report and demonstrates that a successful result can be obtained with this technique. Although the prism bone graft technique seems to offer a solution to a potential rather than a real problem, it offers a thick and three-dimensional cortico-cancellous bone graft without violating the iliac crest. Thus, the risk of serious complications resulting from the tricortical iliac crest graft or bicortical full thickness graft harvesting can be eliminated. Moreover, epiphysis of the immature iliac crest can be preserved in a growing child.

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.

A preliminary study of the use of cage and plating for single-segment fusion in degenerative cervical spine disease

Three different surgical methods were used to treat single-segment degenerative cervical spine disease, and the radiological and clinical outcomes were compared. The three groups compared were: 21 cases of anterior interbody fusion with iliac autograft (group A); 20 cases of anterior plate fixation with iliac autograft (group B); and 19 cases of carbon cage fusion and anterior plate fixation (group C). Bone union and changes in Cobb’s angle and interbody space were evaluated using radiographs and clinical results by the method of Odom et al. Cobb’s angle increased in group C, which was significantly better than the decrease in groups A and B. The interbody space decreased in group C, but was significantly less than the decrease in groups A and B. Carbon cage and anterior plate fixation can be used as an alternative surgical treatment modality for single-segment degenerative cervical spine and can provide early stability, maintain the interbody space and cervical lordosis, reduce operation time and minimize complications at the bone graft donor site.

Early Composite Cranioplasty in Infants with Severe Aplasia Cutis Congenita: A Report of Two Cases

Severe cutis aplasia congenita has traditionally been treated with initial soft tissue coverage and delayed cranioplasty. We advocate the technique of early composite reconstruction of both bone and soft tissues. Two cases of cutis aplasia congenita with large skull defects (6 x 10 cm, 8 x 8 cm) of superficial layers, skull, and dura are presented. In each case, composite reconstruction was undertaken before 2 weeks of age with restoration of bony and soft tissue coverage through autologous, full-thickness cranial bone grafts and scalp flaps. Both children have been followed up over 2 years with clinical examination and computed tomography (CT) scans. In both cases, defects were completely repaired postoperatively and remained closed 2 years later. Complete regeneration of calvarial bone graft donor sites were documented by CT scan. Head shape and circumference were normal at 2-year follow up.

The Medial Surface of the Mandible as an Alternative Source of Bone Grafts in Orthognathic Surgery

A technique of harvesting bone grafts from the medial surface of the angle of the mandible during a bilateral sagittal split osteotomy procedure is described. In 20 patients who underwent mandibular setback for the correction of class III dentofacial deformities, bone grafts were harvested from the medial mandibular angle and used for simultaneous augmentation of the midface or for interpositioning and stabilization of the maxilla after LeFort I maxillary anterior or inferior repositioning. The mean postoperative follow-up was 6 months (range, 3-12 months). No complications occurred, and postoperative morbidity was similar to that encountered by patients who undergo sagittal split osteotomy without bone harvest. The technique described shows that the medial mandibular angle is a suitable donor site for membranous bone grafts in patients who undergo sagittal split osteotomy.

Failure of reconstitution of open-section, posterior iliac-wing bone graft donor sites after lumbar spinal fusion. Observations with implications for the etiology of donor site pain.

The objective of this cohort study--conducted at a regional trauma unit in southern Ontario, Canada--was to review the imaging history of open-section, iliac-wing bone graft donor sites in lumbar fusion patients. Intervention entailed review of available X-ray and CT scan images for all patients undergoing lumbar fusion with iliac autograft in the senior author's practice over a 4-year period. Outcome was radiographic confirmation of the absence of bony reconstitution at the iliac harvest site. Of 239 primary fusions performed, 209 complete imaging records were available for review. The images of a further 20 patients who had surgery with the senior author prior to the study period and who presented at the office in the first half of 2000 were also assessed. All cases showed persistence of the iliac donor harvest site defect. Only minimal marginal sclerosis to suggest attempted remodeling was observed. We conclude that iliac-wing bone graft donor sites do not remodel. Given that iliac harvesting is known to increase strain in the pelvis, and that lumbosacral stabilization increases stress in the pelvis, permanent deficiency of iliac bone stock at donor harvest site may be a factor in both primary donor site pain and the observed high frequency of this problem in lumbosacral fusion patients.

P99. Anterior cervical spine fusion rates using a machined frozen corticocancellous allograft

BACKGROUND CONTEXT: While the use of autologous iliac crest bone graft (AICBG) has long been regarded the “gold standard” for anterior cervical discectomy and fusion; increasing numbers of surgeons are abandoning its use in favor of nonautologous materials. Bone graft donor site pain and morbidity, as well as increased operative time are factors cited by surgeons for this trend. The most commonly used substitute for AICBG is human cadaveric allogeneic bone. Freeze-dried allografts may be stored at room temperature and have an indefinite shelf life; however, the process of freeze-drying can reduce mechanical strength by 50% compared with frozen grafts. Frozen allografts maintain their mechanical strength and can be stored for up to 1 year.

Psoas sheath block for providing analgesia for iliac crest donor site pain

The iliac crest is often used as a donor site for bone grafting. The pain experienced by the patient postoperatively can be worse at the donor site than at the main operative site. We describe an effective method of providing good postoperative analgesia for the iliac crest with the use of a psoas sheath catheter and an infusion of local anaesthetic.

Iliac crest reconstruction with a bioactive ceramic spacer.

This study aimed to investigate the long-term clinical results of the apatite wollastonite-containing glass ceramic (AWGC) iliac spacer and to discuss its efficacy in reconstruction of the bone graft donor site at the iliac crest. Thirty-one patients were studied for more than 10 years. All patients underwent anterior spinal fusion using autogenous tricortical iliac bone graft. After harvest of tricortical iliac bone graft, an AWGC iliac spacer ranging from 15 mm to 70 mm in length was press-fitted into the gap. Long-term clinical results were obtained from radiological and blood examinations. Thirty patients (97%) were satisfied with the spacer. There was new bone formation around the spacer on the radiograph. There was no abnormal silicon concentration in blood examinations. AWGC iliac spacer appears to be useful in the reconstruction of harvested iliac crest. New bone formation occurs, reducing the defect size.

The Classic: Revision of Aseptic Loose Total Hip Arthroplasties

The Classic: Revision of Aseptic Loose Total Hip Arthroplasties

The Results of Long Segment Posterolateral Fusion in Degenerative Lumbar Spinal Disorders

Purpose: The purpose of this study was to evaluate the safety and the validity of the long level posterolateral fusion with pedicle screw augmentation in the surgical treatment of degenerative lumbar spinal disorders in older patients. Materials and Methods: A radiological evaluation such as fusion rate, the changes of lordotic angle, metal failure and junctional problem, and clinical results about a 33 patients older than 50 years of age in whom a posterolateral fusion has been performed on more than three segments were analyzed. Results: Arthrodesis was obtained in 23 cases and the changes in the lordotic angle was 7.9. Satisfactory results were obtained in 20 cases, fair in 8 and poor in 5 cases. Satisfactory results were obtained in 12 of the 16 cases in which S1 was included in the arthrodesis and 8 of the 17 cases in which S1 was not included in the arthrodesis. The post-surgical complications encountered were as follows: Wound infection in 5 cases, metal loosening or failure in 12, bone graft donor site problem in 2 and junctional problems in 8 cases. Revision surgery was performed in 9 cases. Conclusion: Long segment fusion in degenerative lumbar spinal disorders should be considered carefully in old age because of the high rate of post-surgical complications and unsatisfactory clinical outcomes.

The proximal tibia metaphysis: a reliable donor site for bone grafting?

Low complication rates have been reported when cancellous bone is taken from the proximal tibia. The current study was done to determine the volume of cancellous bone that can be harvested from the proximal tibia and to determine the risk for postoperative tibia plateau fracture. The average compressed volume that could be harvested from nine tibiae was 5.4 cc compared with a reported volume of 6.0 cc from the iliac crest. In eight cadavers, the proximal tibia was decancellated in eight tibias. The decancellated and the matching eight contralateral intact tibias were loaded to determine the force required to cause a tibial plateau fracture. The null hypothesis, that there is no difference between the decancellated and the intact tibias, could not be rejected. The current experimental study supports the clinical findings that a sufficient amount of cancellous bone can be harvested from the proximal tibial metaphysis and that the risk of postoperative fracture is not increased. Therefore, the proximal tibia is a reliable cancellous bone graft donor site for clinical practice.