Bone Cylinders Research Articles

A Non-Fusion Technique for Removal of Cervical Disk Prolapse using Minimally Invasive Anterior Cervical Transoseous Approach

Introduction In Acute cervical disk prolapse, root compression is the source of pain. In all established techniques, the removal of cervical disk prolapse is performed either through the disk space or through the foramen or joint (microforaminotomy, Frykholm's procedure). So as a result of these techniques, either bradytrophic tissue with little healing potential is disturbed, or bone structures involved in weight bearing or movement are partiallly resected. Consequently, most of these decompression procedures have to be combined with fusion or disk replacement. Materials and Methods This prospective study included P114 patients (54 females and 46 males) with a mean age of 46.4 years and was operated from 2005 to 2010. Indications were cervical soft disk herniations causing symptomatic root compression. Contraindications included instability of the affected segment, central spine compression, fractures or advanced degeneration. A modified version of Oswestry index and the neck disability index (NDI) for neck and arm pain was recorded preoperatively as well as, 3 m and 1 year postoperatively. Also the visual analog scale (VAS) was recorded before and after the procedure. The approach via a 15 mm skin incision is performed by removing a bone cylinder of 6 mm in diameter from the cranial vertebra temporarily. The sequester is removed under direct visual control of the operating microscope. After decompression the bone cylinder is repositioned. Results The mean operation time per 1 segment was 64.4 minutes and mean blood loss was 82.04 mL. Hospitalization period ranged from 2 to 3 days and patients were mobilized in the same day of operation. Total 98 (98%) patients showed complete recovery of neurological deficits postoperatively. The postoperative mean NDI was improved from 34 (preoperative) to 4.6 (postoperative). Also the mean Oswestry score was improved from 16.4 to 1.6. Corresponding improvement of the VAS for neck and arm pain was also recorded and was improved from 6 to 1.3. All 3 scores were statistically significant ( p = 0.05). The 1-year postoperative functional radiographic assessment showed that there was no significant impairment of the stability of the operated segment according to the criteria of White and Panjabi. Complications: one patient (2%) suffered from recurrence after 4 weeks, that was resolved after reoperation with the same method. There was no dural or root sleeve injury. There was no neurological dificit. Neither an approach related postoperative problem nor an infection did occur. Conclusion Removal of a lateral or foraminal disk prolapse through a bony channel proved to be possible and safe. Since the bone cylinder is put back in situ and proved to be incorporated in the vertebral body there is no permanent lesion of the approach. Short-term reduction of the corpus mechanical strength did not lead to any adverse side effect. Since no significant loss of disk height, kyphosis, or segmental instability did occur, this minimal invasive procedure may be a valuable additional option in the operative treatment of the cervical disk prolapse. I confirm having declared any potential conflict of interest for all authors listed on this abstract No Disclosure of Interest None declared Böhm H, Greiner-Perth R, et al. A new minimally invasive posterior approach for the treatment of cervical radiculopathy and myelopathy. Surgical technique and preliminary results. European Spine Journal 2003;12:268–273 Brunaeu M, Cornelius Jf, George B., et al. Microsurgical cervical nerve root decompression by anterolateral approach. Operative Neurosurgery 2006;2:108–113 Cloward RB: The anterior approach for removal of ruptured cervical discs. Journal of Neurosurgery 1958;15:602–617 Fontanella A. Endoscopy microsurgery in herniated cervical discs. Int Intradiscal Therapy Soc Inc Tenth Ann Meet, Naples, Florida, 1997 (Neurological Research 01 (1999) 21:31–38) Fontanella A. Minimally invasive neurosurgery. A convincing alternative to open surgery. Rivista di Neuroradiologia 1997; 10:541 Fritsch EW, Pitzen T. Zervikale Bandscheibenprothesen. Der Orthopäde 3 2006;35:347–361 Heidecke V., Vogel S., Beurkert W. et al. Ergebnisse nach ventraler Fusion mittels Carbon-bzw. Titancage bei zervikalen Bandscheibenvorfällen. Dissertation zur Erlangung des akademischen Grades Doktor der Medizin. (2004) Hilton L. Minimally invasive tubular access for posterior cervical foraminotomy with three dimensional microscopic visualizationand localization with anterior/posterior imaging. The Spine Journal 2007;7:154–158

A Non-Fusion Technique for Removal of Cervical Disk Prolapse using Minimally Invasive Anterior Cervical Transoseous Approach

IntroductionIn Acute cervical disk prolapse, root compression is the source of pain. In all established techniques, the removal of cervical disk prolapse is performed either through the disk space or through the foramen or joint (microforaminotomy, Frykholm's procedure). So as a result of these techniques, either bradytrophic tissue with little healing potential is disturbed, or bone structures involved in weight bearing or movement are partiallly resected. Consequently, most of these decompression procedures have to be combined with fusion or disk replacement.Materials and MethodsThis prospective study included P114 patients (54 females and 46 males) with a mean age of 46.4 years and was operated from 2005 to 2010. Indications were cervical soft disk herniations causing symptomatic root compression. Contraindications included instability of the affected segment, central spine compression, fractures or advanced degeneration. A modified version of Oswestry index and the neck disability index (NDI) for neck and arm pain was recorded preoperatively as well as, 3 m and 1 year postoperatively. Also the visual analog scale (VAS) was recorded before and after the procedure. The approach via a 15 mm skin incision is performed by removing a bone cylinder of 6 mm in diameter from the cranial vertebra temporarily. The sequester is removed under direct visual control of the operating microscope. After decompression the bone cylinder is repositioned.ResultsThe mean operation time per 1 segment was 64.4 minutes and mean blood loss was 82.04 mL. Hospitalization period ranged from 2 to 3 days and patients were mobilized in the same day of operation. Total 98 (98%) patients showed complete recovery of neurological deficits postoperatively. The postoperative mean NDI was improved from 34 (preoperative) to 4.6 (postoperative). Also the mean Oswestry score was improved from 16.4 to 1.6. Corresponding improvement of the VAS for neck and arm pain was also recorded and was improved from 6 to 1.3. All 3 scores were statistically significant (p = 0.05). The 1-year postoperative functional radiographic assessment showed that there was no significant impairment of the stability of the operated segment according to the criteria of White and Panjabi. Complications: one patient (2%) suffered from recurrence after 4 weeks, that was resolved after reoperation with the same method. There was no dural or root sleeve injury. There was no neurological dificit. Neither an approach related postoperative problem nor an infection did occur.ConclusionRemoval of a lateral or foraminal disk prolapse through a bony channel proved to be possible and safe. Since the bone cylinder is put back in situ and proved to be incorporated in the vertebral body there is no permanent lesion of the approach. Short-term reduction of the corpus mechanical strength did not lead to any adverse side effect. Since no significant loss of disk height, kyphosis, or segmental instability did occur, this minimal invasive procedure may be a valuable additional option in the operative treatment of the cervical disk prolapse.I confirm having declared any potential conflict of interest for all authors listed on this abstractNoDisclosure of InterestNone declaredBöhm H, Greiner-Perth R, et al. A new minimally invasive posterior approach for the treatment of cervical radiculopathy and myelopathy. Surgical technique and preliminary results. European Spine Journal 2003;12:268–273Brunaeu M, Cornelius Jf, George B., et al. Microsurgical cervical nerve root decompression by anterolateral approach. Operative Neurosurgery 2006;2:108–113Cloward RB: The anterior approach for removal of ruptured cervical discs. Journal of Neurosurgery 1958;15:602–617Fontanella A. Endoscopy microsurgery in herniated cervical discs. Int Intradiscal Therapy Soc Inc Tenth Ann Meet, Naples, Florida, 1997 (Neurological Research 01 (1999) 21:31–38)Fontanella A. Minimally invasive neurosurgery. A convincing alternative to open surgery. Rivista di Neuroradiologia 1997; 10:541Fritsch EW, Pitzen T. Zervikale Bandscheibenprothesen. Der Orthopäde 3 2006;35:347–361Heidecke V., Vogel S., Beurkert W. et al. Ergebnisse nach ventraler Fusion mittels Carbon-bzw. Titancage bei zervikalen Bandscheibenvorfällen. Dissertation zur Erlangung des akademischen Grades Doktor der Medizin. (2004)Hilton L. Minimally invasive tubular access for posterior cervical foraminotomy with three dimensional microscopic visualizationand localization with anterior/posterior imaging. The Spine Journal 2007;7:154–158

Loss of sympathetic nerve fibers in vital intertrochanteric bone cylinders lateral to osteonecrosis of the femoral head

ObjectivesAlthough etiology in osteonecrosis of the femoral head mainly depends on alterations of bone blood flow, vasoregulatory nerve fibers of the sympathetic and sensory nervous system have never been investigated in bone of osteonecrosis patients. This study aimed to demonstrate density of sympathetic and sensory nerve fibers in femoral head and, for comparison, adjacent periosteum, and synovium of the hip joint in patients with osteonecrosis. MethodsImmunofluorescence staining techniques were applied using specific nerve fiber markers. A total of 10 patients with early femoral head osteonecrosis (ARCO I-II), 10 with late femoral head osteonecrosis (ARCO III-IV), and 10 patients with osteoarthritis of the hip were investigated. ResultsIn the bone of the femoral head, density of sympathetic nerve fibers was lower in early and late osteonecrosis compared to osteoarthritis. There was a marked preponderance of sympathetic over sensory nerve fibers in bone of osteoarthritis patients, which was opposite in early and late femoral head osteonecrosis. In periosteum, density of sympathetic nerve fibers was similar in all three groups but density of sensory nerve fibers and cellularity were higher in early osteonecrosis compared to the other two groups. Discussion/ConclusionsDue to the different affinity of norepinephrine for α-adrenoceptors (high affinity) and β-adrenoceptors (low affinity), the loss of sympathetic nerve fibers relative to sensory nerve fibers in femoral head osteonecrosis might change the femoral head blood flow (towards α-adrenergic vasoconstriction). Higher density of sensory nerve fibers and cellularity in periosteum might indicate an inflammatory response in early osteonecrosis.

How Precise Is Dental Volumetric Tomography in the Prediction of Bone Density?

Objectives. The aim of this study was to review the bone density assessment techniques and evaluate the macroscopic structure of bone specimens scored by Hounsfield Units (HUs) and decide if they are always in congruence. Methods. The mandible of a formalin-fixed human cadaver was scanned by dental volumetric tomography (DVT) for planning of the specimen positions and fabrication of a surgical guide and a surgical stent was fabricated afterwards. Bone cylinders of 3.5 mm diameter and 5 mm length, were excised from the mandible using the surgical stent with a slow speed trephine drill. After removal of the cylinders two more scans were performed and the images of the first scan were used for the determination of the HU values. The removed bone cylinder was inspected macroscopically as well by micro-CT scan. Results. The highest HU values were recorded in the interforaminal region, especially in the midline (408–742). Posterior regions showed lower HU values, especially the first molar regions (22–61 for the right; 14–66 for the left first molar regions). Conclusion. Within the limitations of this pilot study, it can be concluded that HU values alone could be a misleading diagnostic tool for the determination of bone density.

Autologous bone cylinder transplantation with cannulated screw re-stabilisation: a new treatment option for delayed fracture healing of the femoral neck

Delayed fracture healing and non-unions of the femoral neck after lag screw osteosynthesis occur particularly in multiply injured young patients, and then surgical revision is often required. Currently no evidence-based treatment guidelines exist and therapeutic options include both hip arthroplasties and femoral head-maintaining operations. Here we report on young patients with delayed fracture healing of the femoral neck. Patients underwent revision surgery by autologous bone cylinder transplantation with mechanical re-stabilisation by cannulated lag screws. We reviewed all patients after femoral neck screw osteosynthesis and identified eight patients at 7.3 [3-24] months after initial osteosynthesis with persisting, or reoccurring postoperative pain. Average patient age was 43 [35-57] years and patient Harris Hip Score (HHS) numbers were low (52 ± 19). Before revision surgery the preoperative CT scans showed a partial bone consolidation (anterior and/or posterior cortices) in the absence of a complete bone consolidation of all cortices. Seven patients were treated by bone cylinder transplantation from the patient's own iliac crest; one patient underwent an inverse bone cylinder procedure. Seven patients were additionally treated by re-insertion of 1-2 lag screws to increase mechanical stability. After revision surgery the average patient follow-up period was 42 [12-89] months. Five patients achieved favourable clinical and radiographic outcome with both complete bone union and return to work within 7.2 ± 2.75 months. One patient showed fracture healing but developed an aseptic femoral head osteonecrosis. Two patients failed to achieve complete bone consolidation. The postoperative HHS was 92 ± 4 in patients with favourable clinical outcome (n = 5) and 89 ± 2 after second revision surgery (2 hip arthroplasties; 1 valgus osteotomy). Both groups had significantly better HHS numbers compared with before surgical revision (p < 0.05). These data show that in this difficult-to-treat subset of young patients with delayed fracture healing of the femoral neck, autologous bone cylinder transplantation with mechanical re-stabilisation should be considered as a promising surgical revision strategy before hip arthroplasty.

Qualitative and Quantitative Evaluation of Bony Structures Based on DICOM Dataset

The aim of this study was to investigate bone mass using different cone-beam computed tomographies (CBCTs) combined with image analysis and to determine whether bone quantity or quality was detected. Different measurements recorded on mandible bones of pigs in the retromolar region were evaluated on ProMax 3D (Planmeca Oy, Finland) and the ILUMA™CT (IMTEC™ Imaging, Ardmore, OK) to calculate a calibration curve. The spatial relationships of pig mandible halves relative to adjacent defined anatomical structures were assessed by means of 3D visualization software. In addition to the screenshot, their bone quality was evaluated in accordance with the Lenkholm and Zarb classification. The CBCT calibration curves based on the measurements taken from the ProMax and ILUMA CT showed linear correlation. Huge Hounsfield units intervals were found between the 2 CBCTs and there was no correlation with the computed tomography. Exact information on the micromorphology of the bone cylinders was not available. A subjective correlation according to Lenkholm and Zarb showed overlapping in all groups. CBCT is a good choice for analyzing bone mass. However, it does not provide any information on bone quality. To obtain information on the microarchitecture of the spongiosa, it is necessary to use a computed tomography with finite element analysis.

Developmental plasticity of human foetal femur-derived cells in pellet culture: self assembly of an osteoid shell around a cartilaginous core

This study has examined the osteogenic and chondrogenic differentiation of human foetal femur-derived cells in 3-dimensional pellet cultures. After culture for 21-28 days in osteogenic media, the pellets acquired a unique configuration that consisted of an outer fibrous layer, an osteoid-like shell surrounding a cellular and cartilaginous region. This configuration is typical to the cross section of the foetal femurs at the same age and was not observed in pellets derived from adult human bone marrow stromal cells. Time course study showed that after 7-14 days, the cells of the inner cellular region were viable, proliferated rapidly, and were immuno-positive for c-myc, as well as for bone sialoprotein and type I collagen. After 21-28 days, the cells accumulated at the inner edge of the osteoid shell. The direction of osteoid formation thus differed from that of periosteal bone formation. Following micro-dissection of the human foetal femurs into epiphyses, bone cylinder and hypertrophic cartilage, epiphyseal chondrocytes and osteoblasts both gave rise to osteoid-shell forming cells. These studies demonstrate the developmental plasticity of human foetal skeletal and epiphyseal chondrocytes and suggest that the microenvironment modulates lineage commitment and matrix formation. Furthermore, this ex vivo model offers a new approach to delineate human bone development as well as a model with potential application for evaluation of therapeutic compounds for bone formation.

Haftfestigkeit eines mit β-Trikalziumphosphat angereichertem Knochenadhäsivs

This investigation describes experimental tests of the biomechanical features of a new resorbable bone adhesive based on methacrylate-terminated oligolactides enhanced with osteoconductive β-tricalcium phosphate. 51 New Zealand white rabbits were randomised to an adhesive group (n = 29) and a control group (n = 22). An extra-articular bone cylinder was taken from the proximal tibia, two stripes of adhesive were applied and the cylinders were replanted. After 10 and 21 days, 3 and 12 months tibial specimens were harvested and the cylinder pull-out test was performed with a servo-hydraulic machine. Additionally the pull-out force was evaluated with the bone-equivalent Ebazell® after 5, 10 and 360 minutes in 14 specimens each. Average pull-out forces in the adhesive group were 28 N after 10 days (control: 57 N), 155 N after 21 days (216 N), 184 N after 3 months (197 N) and 205 N after 12 months (185 N). Investigations with Ebazell® showed almost identical pull-out forces after 5 min, 15 min and 360 min. Adhesive forces were as high as 125 N/cm (2) of adhesive surface and more than 1200 N/g of adhesive mass. The adhesive investigated here has a very good primary adhesive power, compared to the literature data, achieved after only 5 minutes. Even in moist surroundings the adhesive capacity remains sufficient. The adhesive has to prove its resorptive properties in further investigations and in first line its medium-term and long-lasting biocompatibility. Furthermore, biomechanical features will have to be compared to those of conventional fixation techniques.

Osteogenic activity of bone marrow-derived mesenchymal stem cells (BMSCs) seeded on irradiated allogenic bone

Allogenic bone grafting, a technique used in orthopaedic surgery, has several problems, including low osteogenic activity. To overcome the problem, this study aimed to determine whether in vivo osteogenesis could be enhanced using allogenic irradiated bone grafts after seeding with autologous bone marrow-derived mesenchymal stem cells (BMSCs). The allogenic bone cylinders were extracted from ACI rats and sterilized by irradiation. Donor BMSCs were obtained from fresh Fischer 344 (F344) rat bone marrow by cell culture. The allogenic bone with or without BMSCs were transplanted subcutaneously into syngeneic F344 rats. At 4 weeks after transplantation, high alkaline phosphatase (ALP) activity, bone-specific osteocalcin mRNA expression and newly formed bone were detected in the allogenic bone with BMSCs. The origin of the newly formed bone was derived from cultured donor BMSCs. However, none of these identifiers of osteogenesis were detected in either the fresh or the irradiated allogenic bone without BMSCs. These results indicate the availability of autologous BMSCs to heighten the osteogenic response of allogenic bone. Our present tissue-engineering method might contribute to a wide variety of allogenic bone grafting techniques in clinical settings.

T(8;22)(q24;q11) In a Context of Complex Karyotype In Two Patients with B-Cell Lymphoma with Features Intermediate Between Burkitt Lymphoma and Diffuse Large B Cell Lymphoma B (LB/LDCGB)

AbstractAbstract 5093 Background:In some cases, it is difficult to distinguish between the diagnosis of Burkitt lymphoma (LB) and Diffuse Large Cell Lymphoma B (DLCL-B) with MYC gene rearrangement. The WHO classification distinguishes three clinical entities: LB, LB/DLCL-B, DLCL-B on the basis of morphology, immunophenotype and genetic characteristics of malignant cells. The MYC gene is often rearranged with the gene that encodes the heavy chains of immunoglobulins (IgG 14q32) and, less frequently, with the gene that encodes the light chains kappa (2p12) or lambda (22q11). Objective:Describe clinical and biological characteristics of two cases of lymphoma with variant t(8;22)(q24;q11) in a complex karyotype diagnosed BL/DLCL-B according to the WHO classification. Methods and Patients:The cytogenetic study was made in the bone marrow (aspirate or biopsy). Leukocytes were incubated during 24h in RPMI without mitogens. Rearrangements of C-MYC, BCL-2, BCL-6 and IGH were studied for FISH techniques. The results were expressed according to ISCN 2009. Case 1:A man of 46 years who was admitted with symptoms of spinal cord compression with fever and weight loss. During admission were detected anti-HIV antibodies. In the biopsy were observed large cells with irregular nuclei, with clefts and some multilobulated. Imunohistochemistry: CD10 +, CD20 +, CD79 +, bcl2 + and BCL6 +. The Ki67/MIB1 was 95%. Cytogenetic study of bone cylinder showed a complex karyotype: 49, XY, +1, del (1) (p22), der (2), der (3), +7, t (8;22)(q24;q11), +10, del(10)(q24q26)x2 [3]. The FISH study demonstrated the rearrangement of C-MYC and the absence of BCL2 and BCL6 rearrangement. Case 2:A man of 67 year old was admitted for epigastric pain, nausea, vomiting and weight loss. The aspirated cells were of medium and large size, irregularly shaped nuclei, some creases and other poly-lobed with prominent nucleoli. Was detected by immunohistochemistry positivity: CD10, CD20, CD79 and BCL6 Ki67/MIB1 presented a 90%. Cytogenetic study of the bone marrow showed a complex karyotype: 49, XY, t(1;11)(q21;p13),+7, t(7;13) q32;q12), t (8;22)(q24;q11),+12,+19[40]. The FISH study demonstrated presence of the rearrangement of C-MYC and BCL2 and BCL6 rearrangement absence. Conclusions:- Both cases are representative of the clinical entity BL// DLCL-B recently recognized by the WHO: anisocitosicas cells with a nucleus of irregular or poly-lobed, with Ki67/MIB1 <90% and C-MYC rearranged with a complex karyotype. - Both cases showed the t(8;22)(q24;q11) rare variant of Burkitt lymphoma and a trisomy 7, trisomy usually observed in DLCL-B. Disclosures:No relevant conflicts of interest to declare.

Morphometric analysis – Cone beam computed tomography to predict bone quality and quantity

Aim Modified quantitative computed tomography is a method used to predict bone quality and quantify the bone mass of the jaw. The aim of this study was to determine whether bone quantity or quality was detected by cone beam computed tomography (CBCT) combined with image analysis. Materials and procedures Different measurements recorded on two phantoms (Siemens phantom, Comac phantom) were evaluated on images taken with the Somatom VolumeZoom (Siemens Medical Solutions, Erlangen, Germany) and the NewTom 9000 (NIM s.r.l., Verona, Italy) in order to calculate a calibration curve. The spatial relationships of six sample cylinders and the repositioning from four pig skull halves relative to adjacent defined anatomical structures were assessed by means of three-dimensional visualization software. Results The calibration curves for computer tomography (CT) and cone beam computer tomography (CBCT) using the Siemens phantom showed linear correlation in both modalities between the Hounsfield Units (HU) and bone morphology. A correction factor for CBCT was calculated. Exact information about the micromorphology of the bone cylinders was only available using of micro computer tomography. Conclusion Cone-beam computer tomography is a suitable choice for analysing bone mass, but, it does not give any information about bone quality.

Anterior cruciate ligament reconstruction with bone-hamstring-bone hybrid procedure

Dear Editors,We read the article ‘‘Augmentation of autologous ham-string graft during anterior cruciate ligament reconstructionusing the bone chip technique’’ by Nha et al. [3] with greatinterest. We would like to commend the authors on theirwork.ACL reconstruction with bone-hamstring-bone (BHB) isa hybrid procedure that lacks the disadvantages of thebone-patellar tendon-bone and semitendinosus and gracilistendon methods while retaining the advantages of thesemethods. Nha et al. [3] described very interesting techniqueto augment the thickness of the hamstring tendon graftduring ACL reconstruction using cancellous bone chipsfrom the femoral intercondylar notch. But this technique isnot new, it should be noted that this technique was pub-lished several years ago. Liu et al. [1] in 1995 measured theinitial fixation strength of a new graft, bone-hamstring-bone (BHB), for reconstruction of the anterior cruciateligament (ACL) in 79 porcine knees and compared it withthat of the normal porcine ACL and of the bone-patellartendon-bone (BPB) graft. Takeuchi et al. [4] in 2002described composite graft prepared by folding the gracilisand the semitendinosus tendons twice and flanking the endsby bone blocks obtained from the tibia. Milankov et al. [2]in 2007 use two cancellous bone cylinders, were taken outof the tibial tunnel, by use of a cancellous bone extractor,and fixed to both ends of the graft by use of sutures. Oneend of the graft was put into a pressing device to achieve agraft diameter of 9 or 10 mm, and then the other end waspressed. By doing so, very strong end parts of the graftwere obtained.We also believe, when using the AM portal techniquefor creation femoral tunnel, it is rarely needed to makenotchplastic, so the usage of bone from that place is notnecessary because it leads to additional damage. It is betterto use cancellous bone cylinders taken out of the tibialtunnel.References

Development of the Tarsometatarsal Skeleton by the Lateral Fusion of Three Cylindrical Periosteal Bones in the Chick Embryo (Gallus gallus)

An avian tarsometatarsal (TMT) skeleton spanning from the base of toes to the intertarsal joint is a compound bone developed by elongation and lateral fusion of three cylindrical periosteal bones. Ontogenetic development of the TMT skeleton is likely to recapitulate the changes occurred during evolution but so far has received less attention. In this study, its development has been examined morphologically and histologically in the chick, Gallus gallus. Three metatarsal cartilage rods radiating distally earlier in development became aligned parallel to each other by embryonic day 8 (ED8). Calcification initiated at ED8 in the midshaft of cartilage propagated cylindrically along its surface. Coordinated radial growth by fabricating bony struts and trabeculae resulted in the formation of three independent bone cylinders, which further became closely apposed with each other by ED13 when the periosteum began to fuse in a back-to-back orientation. Bone microstructure, especially orientation of intertrabecular channels in which blood vasculature resides, appeared related to the observed rapid longitudinal growth. Differential radial growth was considered to delineate eventual surface configurations of a compound TMT bone, but its morphogenesis preceded the fusion of bone cylinders. Bony trabeculae connecting adjacent cylinders emerged first at ED17 in the dorsal and ventral quarters of intervening tissue at the mid-diaphyseal level. Posthatch TMT skeleton had a seemingly uniform mid-diaphysis, although the septa persisted between original marrow cavities. These findings provide morphological and histological bases for further cellular and molecular studies on this developmental process.

Symphyseal Bone Cylinders Tapping With the Dental Implant Into Insufficiency Bone Situated Esthetic Area at One-Stage Surgery: A Case Report and the Description of the New Technique

Periodontal defects and trauma at the anterior maxillary region can cause a severe alveolar ridge deficiency resulting in an unesthetic view. Ideal implant positioning can be compromised by inadequate alveolar bone in terms of height and width. Reconstruction of osseous defects with autogenous bone allows ideal implant positioning and creates a more natural soft and hard tissue profile, which influences esthetic crown anatomy at the anterior maxillary region. In this case report, an alveolar ridge defect due to periodontally compromised tooth extraction was filled with autogenous bone cylinder and dental implant at one-stage surgery. In the presented case, a new technique was described which included bone reconstruction of the defects at the anterior maxillary region and simultaneous placement of the dental implant.

Advancements in Orthopedic Intervention: Retrograde Drilling and Bone Grafting of Osteochondral Lesions of the Knee Using Magnetic Resonance Imaging Guidance

Computer-assisted surgery is currently a novel challenge for surgeons and interventional radiologists. Magnetic resonance imaging (MRI)-guided procedures are still evolving. In this experimental study, we describe and assess an innovative passive-navigation method for MRI-guided treatment of osteochondritis dissecans of the knee. A navigation principle using a passive-navigation device was evaluated in six cadaveric knee joint specimens for potential applicability in retrograde drilling and bone grafting of osteochondral lesions using MRI guidance. Feasibility and accuracy were evaluated in an open MRI scanner (1.0 T Philips Panorama HFO MRI System). Interactive MRI navigation allowed precise drilling and bone grafting of osteochondral lesions of the knee. All lesions were hit with an accuracy of 1.86 mm in the coronal plane and 1.4 mm the sagittal plane. Targeting of all lesions was possible with a single drilling. MRI allowed excellent assessment of correct positioning of the cancellous bone cylinder during bone grafting. The navigation device and anatomic structures could be clearly identified and distinguished throughout the entire drilling procedure. MRI-assisted navigation method using a passive navigation device is feasible for the treatment of osteochondral lesions of the knee under MRI guidance and allows precise and safe drilling without exposure to ionizing radiation. This method may be a viable alternative to other navigation principles, especially for pediatric and adolescent patients. This MRI-navigated method is also potentially applicable in many other MRI-guided interventions.

Fracture resistance and reinforcement of immature roots with gutta percha, mineral trioxide aggregate and calcium phosphate bone cement: a standardized in vitro model

Endodontic treatment of immature teeth is often complicated because of flaring root canals and open apices for which apexification is needed. Long-term prognosis for these teeth is surprisingly low because of cervical root fractures occurring after an impact of weak forces. In this study, an experimental model was developed to determine the fracture resistance of immature teeth and to test the hypothesis that endodontic materials succeed in reinforcing them. Compact and hollow bone cylinders from bovine femurs were used as standardized samples. In order to evaluate the experimental model, fracture resistance in both groups was evaluated by determining the ultimate force to fracture (UFF) under diametral tensile stress. Analysis of variance (ANOVA) revealed a statistically significant difference between the mean values of UFF for both groups, independently of the sampling location or subject. In a following setting, the hypothesis that obturation with gutta percha (GP), mineral trioxide aggregate (MTA), or calcium phosphate bone cement (CPBC) reinforces the hollow bone samples was investigated. Obturation resulted in a significant reinforcement for all materials, but the degree of reinforcement depended on the material. The experimental model appeared to be suitable for in vitro investigation of reinforcement and fracture resistance in a standardized way.

Biodegradable Screw versus a Press-Fit Bone Plug Fixation for Hamstring Anterior Cruciate Ligament Reconstruction

Background Press-fit fixation of a tendon graft has been advocated to achieve tendon-to-bone healing. Hypothesis Fixation of hamstring tendon grafts with a porous bone scaffold limits bone tunnel enlargement compared with a biodegradable interference screw fixation. Study Design Randomized controlled trial; Level of evidence, 1. Methods Between 2005 and 2006, 20 patients (17 men, 3 women) with a primary reconstruction of the anterior cruciate ligament (ACL) were enrolled in this study. Patients were randomized to obtain graft fixation in the tibial tunnel either by means of an interference screw (I) or a press-fit fixation with a porous bone cylinder (P). At 3 months after surgery, a computed tomography (CT) scan of the knee was performed, and tunnel enlargement was analyzed in the coronal and sagittal planes for the proximal, middle, and distal thirds of the tunnel. After 6 months and 1 and 2 years, radiographs of the knee in the sagittal and coronal plane were analyzed for bone tunnel widening. The International Knee Documentation Committee (IKDC), Tegner, and Lysholm scores of both groups were compared after 1 and 2 years. Results The bone tunnel enlargement determined by CT was 106.9% ± 10.9% for group P and 121.9% ± 9.0% for group I (P < .02) in the anteroposterior (AP) plane and 102.8% ± 15.2% versus 121.5% ± 10.1% in the coronal plane (P < .01). The IKDC, Tegner, and Lysholm scores improved in both groups from preoperatively to postoperatively without significant differences between the 2 groups. There was a trend to higher knee stability in group P after 3 months (0.6 ± 1.4 mm vs 1.8 ± 1.5 mm; P = .08). Conclusion Both interference screw and a press-fit fixation lead to a high number of good or very good outcomes after ACL reconstruction. Tibial press-fit fixation decreases the amount of proximal bone tunnel enlargement.

Influence of bone‐derived matrices on generation of bone in an ectopic rat model

Most bone regeneration experimental models that test bone-derived matrices take place in conjunction with the native bone. Here, we compared the relative effectiveness of bone matrix components on bone-marrow-directed osteogenesis in an ectopic model. Cortical bone cylinders consisted of diaphysis of DA rat femurs. They were either demineralized (DBM), deproteinized (HABM), or nontreated (MBM). Fresh bone marrow was placed into cylinders and implanted at subcutaneous thoracic sites of 2-month-old DA rats. At designated times the cylinders were surgically removed from the animals. Microradiographs of DBM and histology of DBM and MBM cylinders demonstrated progressive increase in mineralized bone volume and its trabecular configuration. Bone filled the inner volume of DBM and MBM cylinders within 4 weeks, while in HABM cylinders mostly granulation tissue developed. In the DBM cylinders cartilage deposited within 10 days, while in the MBM cylinders bone was directly deposited. As early as day 3 after marrow transplantation, marrow cells interacting with DBM increased significantly the genes that express the cartilage and the bone phenotype. In conclusion, organic components of bone are needed for marrow-directed osteogenesis.

Prefabricated bony radial forearm flap for secondary mandible reconstruction after radiochemotherapy

Primary reconstruction of the mandible is the golden standard of surgical treatment after ablative tumor surgery. Many different microvascular bone grafts are used to reduce wound healing complications at the severely compromised recipient site. The loss of primary grafts due to radiotherapy or osteoradionecrosis can make secondary mandibular reconstruction necessary. To address this problem, we developed the technique of the prefabrication of a radial forearm flap with cancellous bone. The aims were to establish these techniques into the clinical routine and to create a safe and reliable flap with low donor site morbidity. In patients who had undergone ablative tumor surgery radiochemotherapy, and primary reconstruction, prefabricated bony radial forearm flaps (PBRFFs) were applied for secondary reconstruction of the mandible. Cylinders of cancellous bone taken from the iliac crest were implanted in the lower forearm to allow the necessary vascularization. After a healing period of 4 weeks, the PBRFF was elevated and grafted into the mandibular defect. All grafts healed uneventfully. However, 1 case required revision of the venous anastomosis after 2 days. The transplants improved the contour of the lower face enabling a good correction of the facial asymmetry. During the follow-up of up to 4 years, the radiographic controls showed good bony consolidation between the graft and the stumps of the mandible as well as formation of cortical bone around the cancellous bone cylinders. These results demonstrate that the PBRFF is a safe and reliable graft which provides alternate solution in which other microvascular bone grafts have already failed. In the future, the iliac bone graft may be replaced with scaffold seeded with stem cells for further reduction of donor site morbidity.

Bone Augmentation in Dental Implantology Using Press-Fit Bone Cylinders and Twin-Principle Diamond Hollow Drills: A Case Series

Bone transplants are mostly prepared with cutting drills, chisels, and rasps. These techniques are difficult for unexperienced surgeons, and the implant interface is less precise due to unstandardized preparation. Cylindrical bone transplants are a known alternative. Current techniques include fixation methods with osteosynthesis screws or the dental implant. A new bone cylinder transplant technique is presented using a twin-drill principle resulting in a customized pressfit of the transplant without fixation devices and combining this with the superior grinding properties of a diamond coating. New cylindrical diamond hollow drills are used for customized press fit bone transplants in a case series of five patients for socket reconstruction in the front and molar region of maxilla and mandibula with and without simultaneous implant placement. The technical approach was successful without intra or postoperative complications during the acute healing phase. The customized press fit completes a technological trias of bone cylinder transplant techniques adding to the assisted press fit with either osteosynthesis screws or the dental implant itself.