Jin Iida

Osteogenic potential of cultured bone/ceramic construct: comparison with marrow mesenchymal cell/ceramic composite.

Osteogenesis occurs in porous hydroxyapatite (HA) when porous HA blocks combined with marrow mesenchymal cells are grafted in vivo. In vitro bone formation occurs in HA pores when HA combined with marrow cells is cultured in osteogenic medium containing dexamethasone. This cultured bone/HA construct possesses higher osteogenic ability when it is grafted in vivo. In the present study, we compared the osteogenic potential of a cultured bone/HA construct with that of a marrow mesenchymal cell/HA composite. Marrow cells were obtained from the femoral bone shaft of 7-week-old, male Fischer 344 rats and were cultured in T-75 flasks. Cells were concentrated, then frozen and stored in liquid nitrogen for 6 months. The cryopreserved cells were then thawed and prepared for subculture in porous HA (5 × 5 × 5 mm, Interpore 500) and for implantation with porous HA. After 2 weeks of subculture, three cultured bone/HA constructs were separately implanted in the right side of the back of each syngeneic 7-week-old male Fischer rat, and three thawed cell/HA composites (without subculture) were separately implanted in the left side. These implants were harvested at 2 or 4 weeks postimplantation, and prepared for histological, biochemical, and genetic analysis. Alkaline phosphatase activity and osteocalcin content of cultured bone/HA constructs were much higher than those of the cell/HA composites at 2 and 4 weeks postimplantation. Histological examination and gene expression data agreed with these findings. The culture technique discussed herein should facilitate the development of biosynthetic bone implants with higher osteogenic capacity.

Cervical laminoplasty combined with muscle release in patients with athetoid cerebral palsy.

Study Design. A retrospective study comparing cervical laminoplasty with or without muscle release for the treatment of cervical myelopathy resulting from athetoid cerebral palsy. Objective. To assess the effectiveness of muscle release in the treatment of athetoid cerebral palsy. Summary of Background Data. While anterior and/or posterior spinal fusion has been generally accepted as necessary in surgical treatment for cervical myelopathy due to athetoid cerebral palsy, several studies have shown relatively favorable results following laminoplasty. Better results can be obtained by combining muscle release. Methods. Study participants were 10 patients who underwent cervical laminoplasty combined with muscle release (mean age, 44.6 years) and 15 patients who underwent cervical laminoplasty alone (mean age, 48.2 years). Therapeutic outcomes 1 year after surgery, as assessed by Kurokawa’s methods and JOA scores, were compared between groups. Results. Recovery rate 1 year after surgery was significantly higher for the muscle release group than for the control group. In both groups, recovery rates were significantly better for patients who could walk before surgery. Conclusions. Cervical laminoplasty combined with muscle release for the treatment of cervical myelopathy due to athetoid cerebral palsy is effective in simplifying postoperative therapy and improving JOA scores.

Alumina Ceramic Talar Body Prosthesis for Idiopathic Aseptic Necrosis of the Talus

A new prosthesis made of alumina ceramic was developed to replace the collapsed talar body. Prostheses were implanted in three patients who had idiopathic aseptic necrosis of the talus. The artificial talar body was designed with reference to the contralateral talus. The collapsed talar body was removed using a lateral transfibular approach and the prosthesis was fixed to the residual talar neck with cement. The mean follow-up period was 20 months. The score on the AOFAS ankle hindfoot scale improved from 37 points to 82 points when measured at the follow-up point. Remarkable pain relief and improvement of walking ability were obtained in all patients. Under postoperative radiography, prostheses showed good congruency both with the tibia and posterior facet of the calcaneus in all patients. Although the follow-up duration was short, results were satisfactory. Alumina ceramic has high compatibility with articular cartilage and is a good material for the artificial talar body. We believe that the talar body replacement is the only feasible method for retaining hind-foot function. Introduction Idiopathic aseptic necrosis of the talus is a rare morbid condition and frequently develops into collapse of the talar body. Once collapse has occurred, treatment using conventional surgical procedures proves extremely difficult. We have therefore recently devised an alumina ceramic talar body prosthesis for replacement (Fig. 1). The purpose of this study was to evaluate the short-term clinical results of using this prosthesis. Fig. 1 Alumina ceramic talar body prosthesis Key Engineering Materials Online: 2003-05-15 ISSN: 1662-9795, Vols. 240-242, pp 805-808 doi:10.4028/www.scientific.net/KEM.240-242.805

Magnification Error in Digital Radiographs of the Cervical Spine Against Magnetic Resonance Imaging Measurements

Study Design Prospective study. Purpose The main purpose of this study was to clarify the range of magnification errors on digital plain radiographs and to determine if there is a correlation between the body mass index (BMI) of a patient and the magnification error. Overview of Literature Most clinicians currently use digital plain radiography. This new method allows one to access images and measure lengths and angles more easily than with the past technologies. In addition, conventional plain radiography has magnification errors. Although few articles mention magnification errors in regards to digital radiographs, they are known to have the same errors. Methods We used plain digital radiography and magnetic resonance imaging (MRI) to acquire images of the cervical spine with the goal of evaluating magnification errors by measuring the anteroposterior vertebral body lengths of C2 and C5. The magnification error (ME) was then calculated: ME=(length on radiograph-length on MRI)/length on MRI ×100 (%). The correlation coefficient between the magnification error and BMI was obtained using Pearsons correlation analysis. Results Average magnification errors in C2 and C5 were approximately 18.5%±5.4% (range, 0%-30%) and 20.7%±6.3% (range, 1%-32%). There was no positive correlation between BMI and the magnification error. Conclusions There were magnification errors on the digital plain radiographs, and they were different in each case. Maximum magnification error differences were 30% (C2) and 31% (C5). Based on these finding, clinicians must pay attention to magnification errors when measuring lengths using digital plain radiography.

Posterior Fixation of a Cervical Fracture Using the RRS Loop Spine System and Polyethylene Tape in an Elderly Ankylosing Spondylitis Patient: A Case Report

An 80-year-old woman presented with neck pain and paraparesis of Frankel C in her upper and lower extremities after falling. Imaging revealed an ankylosing cervical spine and a fracture line running obliquely from the anterior C3-4 to the posterior C4-5 level. Posterior fixation from the occi pit to T3 was performed using the RRS Loop Spine System and concomitant polyethylene tape fixation. This system is characterized by the uniqueness of how it screws to the occi pit and its use of a fixation rod with a larger diameter than in other instrumentation devices for use in the cervical region. Sublaminar banding using polyethylene tape was used to secure fixation. Her postoperative course was unremarkable, and her neck pain was relieved, although neurological improvement was minor. To our knowledge, this is the first report of an application of the RRS Loop Spine System to an ankylosing spondylitis patient with a cervical fracture.

Posterolateral Lumbar Fusion by Tissue Engineered Bone

Posterolumbar fusion, which involves placing a bone graft in the posterolateral portion of the spine, has been applied to patients with lumbar instability due to structural defects or regressive degeneration. However, harvesting cancellous bone from the ilium is associated with severe postoperative pain, and patients experience more pain at the harvest site than at the graft site, thus resulting in poor patient satisfaction. If a tissue engineering approach was used to produce autogenous bone ex vivo with culture techniques, spinal fusion could be performed without damaging normal tissues. In all patients, 10 to 20 mL of bone marrow fluid was collected from the ilium and cultured in MEM containing autologous serum or fetal bovine serum and an antibiotic. After two weeks in primary culture, the marrow mesenchymal cells were seeded onto porous beta-TCP block, and tissue engineered bone were fabricated as we reported previously. Decompressive laminectomy and posterolateral lumbar fusion with use of the tissue engineered bone thus obtained were then done. In all patients, the implanted artificial bone survived and bone regeneration was detected radiographically, and the clinical symptoms were improved. Short term follow-up has shown that the bone implants were effective in all of the patients. There were no adverse reactions related to implantation. The use of this tissue engineered bone makes it possible to perform osteogenetic treatment without harvesting autogenous bone, thus avoiding pain and pelvic deformity at the site of bone collection and reducing the burden on the patient.

Treatment of Pseudoarthrosis Using Tissue-Engineered Bone Graft

Subjects were graft patients with pseudoarthrosis (average age, 60.3 years; range, 17-85 years). Pseudoarthrosis affected the thoracolumbar spine, the femur, the clavicle, the humerus and the metatarsal. From the ilium (tibia in one patient), 10-20 ml of bone marrow fluid was collected, and then, it was immediately transferred to the culture room and incubated in a flask containing MEM with 15% autologous or fetal bovine serum, etc.. After 2 weeks in primary culture, cells were released by trypsin treatment and were subsequently incubated with porous beta-TCP in order to prepare tissue-engineered artificial bone, according to the previously reported modified culturing technique. Tissue-engineered artificial bone was grafted around the non-union site of each affected long bone, while tissue-engineered artificial bone was grafted via the pedicle of each affected vertebral body. In all patients, favorable bone formation was seen at three months after surgery. In the patients with pseudoarthrosis of the spine, CT and MRI confirmed favorable vertebral body formation. In the patients with pseudoarthrosis of a long bone, the artificial bone was remodeled and favorable bone union was confirmed. In 2 patients in whom bone biopsy was performed during pin removal, bone regeneration was confirmed histologically. With present type of tissue-engineered artificial bone, an artificial material with a high bone regeneration capacity can be prepared by aspiration, which is minimally invasive, and thus when compared to iliac bone grafts, it is possible to radically reduce postoperative pain without damage of autologous bone.

Osteogenic Potential of Cultured Bone/Ceramic Construct: A Comparison with that of Marrow Mesenchymal Cells/Ceramic Composites

Osteogenesis occurs in porous hydroxyapatite (HA) when porous HA blocks combined with marrow mesenchymal cells are grafted into in vivo. In vitro bone formation occurs in pores of HA when HA combined with marrow cells are cultured in the osteogenic medium containing dexamethasone. This cultured bone/HA construct possesses higher osteogenic ability when it is grafted in vivo. In present study, we compared the osteogenic potential of cultured bone/HA construct with that of marrow mesenchyma l cells/HA composite. Marrow cells were obtained from the bone shaft of the femora of 7-w eek-old, male Fischer 344 rats and were cultured in T-75 flasks. The cells were concentrated, then frozen and stor ed in liquid nitrogen for 6 months. The cryopresereved cells were then thawed and prepared for subculture in porous HA (5x5x5mm, Interpore 500) and for implantation with porous HA. Three cultured bone/HA constructs after 2 weeks of subculture were s eparately implanted in the right side of the back of each syngeneic 7-week-old male Fischier rat, and three thaw d cells/HA composites (without subculture) were separately implanted in the le ft sid (8 rats). These implants were harvested 2 and 4 weeks post-implantation, and prepared for biochemica l quantitive analysis. Alkaline phosphatase activity and osteocalcin content f cul ured bone/HA constructs were much higher than those of cells/HA composites at 2 and 4 weeks postimplantation. The culture technique discussed here should allow the development of more biocompatible synthetic bone and joint prostheses, which may obvliate the need for further replacement and could also be used in young patients.

Osteogenetic Effect on Cortical Bone of Cultured Bone/Ceramics Implants

Hydroxyapatite(HA) has been reported to have a good affinity for cancellous bone with high osteoblastic activity, binding directly to such bone. However, little work has been done concerning the strength of binding to cortical bone with a low cellular activity. Bio-artificial bone with a high osteogenetic capacity can be produced by combining cultured bone tissue with an artificial bone material. We examined this bio-artificial bone for its osteogenetic capacity around the bone tissue to evaluate whether the bone is applicable to osteogenetic treatment. Bone marrow cells were collected from the femurs of 7-week-old male Fischer rats, placed into two T75 flasks, and incubated in standard medium. After 2 weeks in primary culture, the cells were seeded on a porous hydroxyapatite block, and incubated in an osteogenic medium prepared by adding 10 nM dexamethasone, ascorbic acid and b-glycerophosphate. to the standard medium. Two weeks later, cultured HA constructs were implanted onto the cortical bone of the femur. At four or eight weeks after implantation, the femur was removed and radiographically and histologically examined for osteogenesis. The bio-artificial bone of HA impregnated with cultured marrow cells bound firmly to the femoral cortex both radiographically and histologically, and calcification indicating new bone formation was observed around the HA. The use of this bio-artificial bone makes it possible to perform osteogenetic treatment without damage to autogenous bone, avoiding pain at the site of bone collection and deformity of the pelvis, and reducing the burden on the patient. Introduction Many studies reported that when marrow cells were cultured in a medium containing compounds such as dexamethasone bone-like tissue formed, and that this cultured bone tissue possessed a calcified collagen matrix, contained osteocalcin (a bone specific protein) and exhibited bone morphogenetic protein activity [1-4]. The results of biochemical and gene expression analyses showed that the osteoblast activity of cultured cells was high. We have reported that it is possible to prepare artificial bone with a potent osteogenic potential by culturing artificial bone materials with functionally active bone tissue [5-10]. We have also documented that the osteoblast activity of such cultured bone constructs is similar to that of cancellous bone [11,12]. Autologous cancellous bone is used for spinal fixation and treatment of pseudoarthrosis due to its high osteogenic potential. Cancellous bone is often harvested from the ilium, but this process can result in pelvic deformation, and there are limitations on the amount of bone that can be harvested. Furthermore, patients often experience uncomfortable levels of pain at the site of bone harvest. On the other hand, cultured bone constructs, with properties comparable to cancellous bone, can be produced by harvesting marrow cells using bone marrow aspiration, which is a minimally invasive procedure. Key Engineering Materials Online: 2003-12-15 ISSN: 1662-9795, Vols. 254-256, pp 745-748 doi:10.4028/www.scientific.net/KEM.254-256.745

Bone Regeneration Therapy with Marrow Mesenchynmal Cells in 10 Cases: Short Term Results

From 10 cases (9 patients, mean age, 65 years : range 17-75 years), bone marrow fluid was collected from the ilium in 9 cases, and from the proximal tibia in 1 case. The diagnosis was humeral fracture, femoral nonunion, metatarsal bone nonunion and osteoarthrosis of the hip joint in 1, 2, 1 and 5 patients, respectively. After 10-20 mL of bone marrow fluid was collected, it was immediately transferred to the culture room and incubated in a flask containing MEM with 15% fetal bovine serum and dexamethasone, etc.. In patients with fracture or femoral nonunion, porous beta-TCP blocks were impregnated with cultured mesenchymal cells and implanted at the site of fracture or nonunion. In 2 patient with osteoarthrosis, cultured bone marrow cells were impregnated into a porous ceramic block and that was grafted into the bone defect of the acetabular shelf or femur. In 3 patients with hip osteoarthrosis, cultured bone marrow cells were spread over the contact area between the artificial joint and the bone and arthroplasty was done without bone cement. Radiological studies revealed callus formation at 2 weeks after grafting in patients with bone fracture or nonunion. At 1 to 2 months after grafting, the grafted construct was adherent to the native bone in the patient in whom cultured artificial bone was grafted to the acetabular shelf or femur. In 3 patients with hip joint replacement, the stem of the artificial joint showed good integration with the bone of the medullary cavity. Treatment with bone marrow mesenchymal cells has a low invasiveness (only marrow aspiration), and therefore it is suitable for weak elderly patients as well as patients in good general condition, because its low invasiveness enables an early return to work. This treatment is expected to be applied more widely in the near future.