Cadaveric Bones Research Articles

Establishing Safe Extra-articular Parameters for Cortical Button Distal Fixation During Ulnar Collateral Ligament Reconstruction

Background: A variety of methods exist for fixation during ulnar collateral ligament (UCL) reconstruction on the ulna for the overhead throwing athlete. Current biomechanical evidence suggests that cortical button fixation may fail at a higher load and under more cycles than interference screw fixation alone, while also minimizing the risk of fracture. A safe angle for placement of this cortical button has not yet been determined. Purpose: To define a safe angle for cortical button deployment during UCL reconstruction to avoid violation of the proximal radioulnar joint (PRUJ). Study Design: Descriptive laboratory study. Methods: Measurements on 100 cadaveric ulna bones, 50 women and 50 men, were obtained referencing the entry point for ulnar fixation, which is 1 cm distal to the ulnar humeral joint line along the medial UCL ridge. Ulnar width at the entry point and distance to the PRUJ were obtained to calculate safe distal angulation, while distance from the entry point to the posterior ulnar crest ulnarly and distance from the PRUJ to the posterior ulnar crest radially were obtained to calculate safe posterior angulation. Ten bony measurements on the same group of specimens were performed by 3 authors to establish an interobserver reliability. Means, quartiles, and outliers were obtained for the calculated angles. Finally, recommended angles of entry were determined to be approximately 1 interquartile range above the upper limit. Results: The mean distal angle of entry that was obtained was 11.32° (SD, ±4.80°; 95% CI, 10.37°-12.27°; P < .001). Three upper limit outliers were discovered: 24.20°, 23.4°, and 21.1°. The mean posterior angle of entry was 40.44° (SD, ±6.18°; 95% CI, 39.22°-41.67°; P < .001). There were no outliers for the posterior angle of entry. Interobserver reliabilities were strong for the 4 measurements. Conclusion: To be safely outside of the PRUJ utilizing a cortical button construct, we recommend 30° distal angulation and 60° posterior angulation for ulnar fixation during UCL reconstruction. Both parameters are 1 quartile above the highest calculated angle of entry. Clinical Relevance: These data define safe parameters for distal fixation during UCL reconstruction and highlight a clear entry point for reference.

Fit assessment of two different anatomically contoured distal femur plate sets on cadaveric bones.

This study aims to investigate the fitness of two anatomic distal femoral plates with cadaveric femurs and to show whether current plates optimally match each femur. Two different sets of plates with five, seven and nine shaft holes were applicated on 62 cadaveric femurs. Ball clay was molded onto the entire inner surfaces of the plates and then the plates were fixed to the bones using two self-locking nylon cable zip ties. The volume of ball clay sandwiched in between the plate and bone was calculated and used as a quantitative fit parameter. Data of each plate were analyzed separately. Using Double Medical Technology IncorporatedTM plates, the mean plate to bone volumes were calculated as 8.4 mL (range, 5-14 mL), 10.0 mL (range, 6-17 mL), and 13.1 mL (range, 7-25 mL) in five, seven and nine-hole plates, respectively. Using Zimmer Biomet IncorporatedTM plates, the mean volumes were 10.5 mL (range, 6-21 mL), 12.7 mL (range, 7-22 mL) and 16.3 mL (range, 8-30 mL) in five, seven and nine-hole plates, respectively. Within each group, the measurements were significantly correlated positively with femoral length. Optimal fit may not be achieved in each femur using current distal femoral plate implant sets. Thus additional sizes of plates should be supplied in the implant sets.

Environmentally-Controlled Near Infrared Spectroscopic Imaging of Bone Water

We have designed an environmentally-controlled chamber for near infrared spectroscopic imaging (NIRSI) to monitor changes in cortical bone water content, an emerging biomarker related to bone quality assessment. The chamber is required to ensure repeatable spectroscopic measurements of tissues without the influence of atmospheric moisture. A calibration curve to predict gravimetric water content from human cadaveric cortical bone was created using NIRSI data obtained at six different lyophilization time points. Partial least squares (PLS) models successfully predicted bone water content that ranged from 0–10% (R = 0.96, p < 0.05, root mean square error of prediction (RMSEP) = 7.39%), as well as in the physiologic range of 4–10% of wet tissue weight (R = 0.87, p < 0.05, RMSEP = 14.5%). Similar results were obtained with univariate and bivariate regression models for prediction of water in the 0–10% range. Further, we identified two new NIR bone absorbances, at 6560 cm−1 and 6688 cm−1, associated with water and collagen respectively. Such data will be useful in pre-clinical studies that investigate changes in bone quality with disease, aging and with therapeutic use.

Osteochondral Allograft Cartilage Transplantation for a Full-Thickness Femoral Condyle Chondral Lesion.

Cartilage lesions of the knee pose a difficult challenge for orthopaedic surgeons. Osteochondral allograft transplantation is an option in the setting of large chondral or osseous defects, or after failure of other treatment options1-3. The use of allograft offers the benefit of utilizing both viable hyaline cartilage and bone4. Fresh allografts are usually transplanted into the femoral condyle, although they can also be used in the patella, tibial plateau, or femoral trochlea1. Research has shown that patients who undergo this procedure for the treatment of focal and diffuse chondral defects have favorable outcomes and satisfaction scores1. The procedure is performed as follows. (1) Preoperative evaluation: patients are evaluated for a cartilage procedure after obtaining history, examination, and imaging (radiographs and magnetic resonance imaging). (2) Approach: a longitudinal parapatellar tendon arthrotomy is performed. (3) Debridement: the lesion is identified, and unstable cartilage is debrided back to stable cartilage. (4) Measure defect: the recipient site depth is measured in 4 positions, as on the face of a clock (12, 3, 6, and 9 o'clock). (5) Template allograft: a sizer is used to template the allograft hemicondyle. (6) Secure and harvest allograft: the allograft is secured in the Osteochondral Allograft Transplantation Surgery (OATS) Workstation (Arthrex) and harvested from cadaver bone. (7) Measure depth: the recipient depth measurements are marked on the allograft. (8) Cut graft: the graft is held with allograft-holding forceps while graft is cut with a saw. (9) Check measurements: allograft measurements are checked to ensure that they match recipient measurements. (10) Round edges: the osseous ends are rounded to assist with insertion of graft. (11) Irrigate: the allograft is irrigated after final cuts. (12) Graft insertion: the graft is inserted after lining up the 12-o'clock position recipient and donor reference marks and is held in place with a press fit. (13) Closure: standard closure in layers is performed.

A systematic review of robotic-assisted unicompartmental knee arthroplasty: prosthesis design and type should be reported.

Robotic-assisted unicompartmental knee arthroplasty (UKA) promises accurate implant placement with the potential of improved survival and functional outcomes. The aim of this study was to present the current evidence for robotic-assisted UKA and describe the outcome in terms of implant positioning, range of movement (ROM), function and survival, and the types of robot and implants that are currently used. A search of PubMed and Medline was performed in October 2018 in line with the Preferred Reporting Items for Systematic Review and Meta-Analysis statement. Search terms included "robotic", "knee", and "surgery". The criteria for inclusion was any study describing the use of robotic UKA and reporting implant positioning, ROM, function, and survival for clinical, cadaveric, or dry bone studies. A total of 528 articles were initially identified from the databases and reference lists. Following full text screening, 38 studies that satisfied the inclusion criteria were included. In all, 20 studies reported on implant positioning, 18 on functional outcomes, 16 on survivorship, and six on ROM. The Mako (Stryker, Mahwah, New Jersey) robot was used in 32 studies (84%), the BlueBelt Navio (Blue Belt Technologies, Plymouth, Minnesota) in three (8%), the Sculptor RGA (Stanmore Implants, Borehamwood United Kingdom) in two (5%), and the Acrobot (The Acrobot Co. Ltd., London, United Kingdom) in one study (3%). The most commonly used implant was the Restoris MCK (Stryker). Nine studies (24%) did not report the implant that was used. The pooled survivorship at six years follow-up was 96%. However, when assessing survival according to implant design, survivorship of an inlay (all-polyethylene) tibial implant was 89%, whereas that of an onlay (metal-backed) implant was 97% at six years (odds ratio 3.66, 95% confidence interval 20.7 to 6.46, p < 0.001). There is little description of the choice of implant when reporting robotic-assisted UKA, which is essential when assessing survivorship, in the literature. Implant positioning with robotic-assisted UKA is more accurate and more reproducible than that performed manually and may offer better functional outcomes, but whether this translates into improved implant survival in the mid- to longer-term remains to be seen. Cite this article: Bone Joint J 2019;101-B:838-847.

A report of two children with Gorham-Stout disease

BackgroundGorham-Stout disease is a rare condition characterized by unifocal and massive type IV osteolysis (variant of idiopathic nonhereditary osteolytic disease) with a slow progression, which is self-limiting for some years. It is characterized by recurrent vascular tumors with disruption of the anatomical architecture and intraosseous proliferation of vascular channels that leads to the destruction and resorption of the bone matrix. The aim of this study is to present the clinical features of this disease, as well as the importance of prompt diagnosis and treatment, with a review of the reported cases.Case reportsWe describe two cases of Gorham-Stout disease between 2013 and 2017 with surgical interventions, follow-up and results. Case one involves an 11-year-old male with involvement of the left iliac bone, with adequate evolution after a surgical procedure with a lyophilized cadaveric tricortical bone allograft. Case two involves a 6-year-old male with cervical spine C1-C3 repercussion; in the protocol for surgical treatment, he presented with signs of spinal cord compression and died.ConclusionDiagnosis of Gorham-Stout disease is made by exclusion, and its clinical presentation varies widely, from spontaneous remission to a fatal outcome.

A review of simulation applications in temporal bone surgery.

BackgroundTemporal bone surgery is a technically challenging and high‐risk procedure in an anatomically complex area. Safe temporal bone surgery emphasizes a consummate anatomic understanding and technique development that requires the guidance of an experienced otologic surgeon and years of practice. Temporal bone simulation can augment otologic surgical training and enable rehearsal of surgical procedures.ObjectivesThe purpose of this article is to provide an updated review of temporal bone simulation platforms and their uses.Data SourcesPubMed literature search. Search terms included temporal bone, temporal bone simulation, virtual reality (VR), and presurgical planning and rehearsal.DiscussionVarious simulation platforms such as cadaveric bone, three‐dimensional (3D) printed models, and VR simulation have been used for temporal bone surgery training. However, each simulation method has its drawbacks. There is a need to improve upon current simulation platforms to enhance surgical training and skills assessment, as well as a need to explore other clinically significant applications of simulation, such as preoperative planning and rehearsal, in otologic surgery.ConclusionsThere is no replacement for actual surgical experience, but high‐fidelity temporal bone models such as those produced with 3D printing and computer simulation have emerged as promising tools in otolaryngologic surgery. Improvements in the fidelity of both 3D printed and VR simulators as well as integration of a standardized assessment format would allow for an expansion in the use of these simulation platforms in training and assessment.Level of Evidence5

Central screw use delays implant dislodgement in osteopenic bone but not synthetic surrogates: A comparison of reverse total shoulder models

Adequate glenoid baseplate fixation in reverse total shoulder arthroplasty (rTSA) is important to achieve, but may prove challenging in the context of glenoid bone loss or osteopenia. Current rTSA testing standards rely upon synthetic bone surrogates, but it is unclear if these models accurately recapitulate the mechanics of osteoporotic bone. Additionally, it also unknown if the use of a central screw effectively provides resistance to micromotion in the milieu of poor quality bone. The purpose of this experiment was to create a novel cyclic load test protocol that elicited clinically relevant failures, so that comparisons of relative motion between baseplates and bones could be made with: (1) synthetic bones and poor quality cadaveric bones, and (2) the use or omission of a central screw. rTSA components were implanted into cadaveric and synthetic bones with and without a central screw. To model a range of loads that may be experienced during abduction, increasing cyclic loads were applied to shoulder joints in 30° of humeral abduction. Cycles and loads prior to permanent deformation exceeding 150 µm, 1 mm, and joint failure were determined using measurements from the test frame and from 3-D motion analysis. Synthetic bones demonstrated significantly more resistance to micromotion in comparison to cadaveric bones. Use of the central screw improved resistance to dislodgement, which was only observed in the cadaveric specimens. This study highlights the need for biomechanical testing with cadaveric specimens, especially when assessing osteopenic or osteoporotic populations.

\u201cSimple mechanical devices did not improve pelvis positioning in AP pelvis radiographs for reliable assessment of the acetabular orientation\u201d

BackgroundThe aim of this study was to develop two simple positioning devices for anteroposterior pelvis radiographs and to evaluate their effect on accuracy of the radiographs for assessment of the acetabular orientation compared with non-instrumented positioning.MethodsThe superior anterior iliac spines and the pubic symphysis were used as anatomical landmarks to obtain a horizontal orientation of the pelvis according to the anterior pelvic plane. Anteroposterior pelvis radiographs were taken of 11 human cadaveric pelvic bones with each of the positioning devices and without any device. Defined measurements were carried out to objectify the tilt and rotation of the pelvis and to assess the cross-over sign as well as the presence of the ischial spine sign. Computed tomography scans were performed as a standard of reference. Bland-Altman-Plots were used to compare the continuous measurement values and Cohen’s Kappa was applied for the categorical data. Intra- and inter-observer reliability was determined by the intraclass correlation coefficient and Cohen’s Kappa.ResultsThe mean values of the measurements showed a high variability. A low correlation of the measurement values was found between the radiographs of the different positioning methods and the computed tomography scans. The intra- and inter-observer reliability was good (Cohen’s Kappa 0.78 and 0.69; intraclass correlation coefficient 0.99 and 0.98).ConclusionThe use of positioning devices did not lead to more accurate anteroposterior pelvis radiographs compared to non-instrumented positioning. Simple positioning devices do not provide standardized anteroposterior pelvis radiographs for reliable assessment of the acetabular orientation.

Sex estimation using sternum part lenghts by means of artificial neural networks

In addition to the pelvis, cranium and phalanges, the sternum is also used for postmortem sex identification. Bone measurements may be obtained on cadaveric bones. Alternatively, computerized tomography may be used to obtain measurements close to the original ones. Moreover, usage of artificial neural networks (ANNs) in the field of medicine has started to provide new horizons. In this study, we aimed to identify sex by an ANN using lengths of manubrium sterni (MSL), corpus sterni (CSL) and processus xiphoideus (XPL) and sternal angle (SA) from computerized tomography (CT) images brought to an orthogonal plane. This study used the thin-slice thoracic CT images of 422 cases (213 female, 209 male) with an age range of 27–60 years brought to the orthogonal plane. Measurements of MSL, CSL, XPL and SA were analyzed with a multilayer artificial neural network that used stochastic gradient descent (SGD) for optimization and two hidden layers. MSL, CSL and XPL were longer, and SA was wider in men (MSL p = 0.000, CSL p = 0.000, XPL p = 0.000, SA p = 0.02). In the case of the two hidden layers of the network with 20 and 14 neurons in the hidden layers, respectively, learning rate of 0.1 and momentum coefficient of 0.9, the accuracy (Acc) of sex prediction was 0.906. In order to define a more realistic performance of the network, bootstrap was run with the confidence interval of 94%. A sensitivity (Sen) value of 0.91 and a specificity (Spe) value of 0.90 were calculated. The success rates that were achieved in sex identification with measurements on the skeleton using ANN were observed to be higher than those achieved by linear models. Also, sometimes all parts of the bones may not be found or might be deformed. In this case, the number of parameters used for the estimation will be incomplete. The ANN has the strong advantage to be able to estimate despite the missing parameter.

Biomechanical in vitro evaluation of a ready-to-use calcium phosphate cement implanted to augment intramedullary nail fixation of a three-part humeral head fracture model.

The aim of this study was the dynamic biomechanical evaluation of a ready-to-use oil-based calcium phosphate cement paste implanted to augment intramedullary nail fixation of a three-part humeral head fracture model. Fractures in the osteoporotic bone are often fractures of the proximal humerus. Secondary fracture displacements due to cut-out in osteoporotic bone have been observed in up to 13% of cases. Procedures have been developed to augment fracture fixation with polymethylmethacrylate to increase stability, but there are still unsolved challenges relating to its material-specific properties. Calcium phosphate cement could be a biological alternative in the augmentation of osteoporotic fractures because of its more favourable material properties. Fracture fixation was performed on eight pairs of human cadaveric bones to stabilize a standardized three-part humeral head fracture model by implantation of the Targon® PH (Braun-Aesculap AG, Tuttlingen, Germany) intramedullary nail and insertion of three head screws and two bicortical shaft screws. The procedure was randomized, and one bone of each pair received calcium phosphate cement augmentation. Custom-made cannulated screws with an open lateral slot facilitated augmentation, making it possible to cement the threaded portion of the screw (1-mL calcium phosphate cement/screw). After the calcium phosphate cement had hardened, the humeri were subjected to dynamic axial loading. Load was progressively increased, monitored by ultrasound-based motion analysis, and total deformation was recorded. Load testing continued until implant failure. The augmented group withstood significantly more cycles before implant failure. The average initial stiffness showed a significant difference between the two study groups. Ultrasonic sensor technology was used to measure angular displacement during testing and a significant difference was found. Calcium phosphate cement offers a potential alternative to implant augmentation in the treatment of osteoporotic humeral head fractures. Future studies are required to confirm these observations clinically in vivo.

Processing and CD3+/CD19+ depletion of cadaveric vertebral bone marrow for primary immunodeficiency patients undergoing sequential bilateral orthotopic lung transplant (BOLT) and bone marrow transplant (BMT)

Background & Aim Patients with primary immune-deficiency (PID) may develop pulmonary complications and at that stage most are ineligible for either lung transplant (LTX) or bone marrow transplant (BMT) alone due to futility. We are conducting a first in human prospective trial, ClinicalTrials.gov: NCT01852370 where PID patients in lung failure -past the opportunity for curative BMT alone- may receive a 2 of 6 HLA antigen-matched cadaveric BOLT and minimum 8 weeks alter cryopreserved BMT from the same deceased UNOS donor. We hypothesized: 1) hematopoietic stem cells prepared from organ donor vertebral bodies (VB) would yield greater CD34+ cell dose compared to iliac crest aspirates-in part due to limited harvest time to avoid delay in the activity of organ recovery teams; 2) cryopreserved CD3/CD19 depleted bone marrow could generate durable hematopoiesis and donor derived immunity. Here we present the first 5 consecutive cases vertebral bone marrow (VBM) processing experience at Children's Hospital of Pittsburgh and subsequent CD3+/CD19+ cell depletion on the CliniMACS® device. With a threshold viability of 70% prior to cryopreservation the CD3/CD19-depleted product must contain 1 × 10E+6/kg CD34+ cells and 1 × 10E+5/kg CD3+ T cells to achieve durable engraftment and reduce the risk of GVHD respectively.® Methods, Results & Conclusion For details of pre/post processing, see Table. Since early 2017 we introduced chest/abdominal cavity wash with 1:1 saline-betadine mix and scrubbing T11-L4VB logs with chlora-prep that has eliminated bacterial contamination for the last 3 products. The first 2 were infused without adverse events following IRB/FDA approved antibiotic prophylaxis. Initially, processing of the VBs was arduous, using a scalpel and wire brush to clean the logs, then dissecting into small pieces with a mallet and osteotome. Since early 2017 a Stryker RemB saw has been used. A physical task that had taken 2 technologists 3 hours to complete has become almost effortless and one tech is freed up. The target pre-cryo CD34+ dose and viabilities have met target at all times, in fact CD34+ recovery has increased >70%, see Table. The entire process (dissection, crushing, filtering, CD3/CD19 depletion and cryopreservation) can be completed in 12 hours with 3 technologists. In summary, we have developed a complex sequence of procedures that even exceeded our target of 2E+06 CD34/kg pre-cryo dose (mean: 4.49E+06) leading to prompt and multilineage engraftment in 3 of the first 4 analyzable patients.

Atlas-based segmentation of temporal bone surface structures.

To develop a time-efficient automated segmentation approach that could identify surface structures on the temporal bone for use in surgical simulation software and preoperative surgical training. An atlas-based segmentation approach was developed to segment the tegmen, sigmoid sulcus, exterior auditory canal, interior auditory canal, and posterior canal wall in normal temporal bone CT images. This approach was tested in images of 20 cadaver bones (10 left, 10 right). The results of the automated segmentation were compared to manual segmentation using quantitative metrics of similarity, Mahalanobis distance, average Hausdorff distance, and volume similarity. The Mahalanobis distance was less than 0.232mm for all structures. The average Hausdorff distance was less than 0.464mm for all structures except the posterior canal wall and external auditory canal for the right bones. Volume similarity was 0.80 or greater for all structures except the sigmoid sulcus that was 0.75 for both left and right bones. Visually, the segmented structures were accurate and similar to that manually traced by an expert observer. An atlas-based approach using a deformable registration of a Gaussian-smoothed temporal bone image and refinements using surface landmarks was successful in segmenting surface structures of temporal bone anatomy for use in pre-surgical planning and training.

Video-augmented fluoroscopy for distal interlocking of intramedullary nails decreased radiation exposure and surgical time in a bovine cadaveric setting.

We aimed to assess the feasibility of a video-augmented fluoroscopy (VAF) technique using a camera-augmented mobile C-arm (CamC) for distal interlocking of intramedullary nails. Three surgeons performed distal interlocking on seven pairs of cadaveric bovine carpal bones using the VAF system and conventional fluoroscopy. We compared radiation exposure, procedure time, and drilling quality between the VAF system and conventional fluoroscopic guidance. Distal interlocking using VAF significantly reduced the number of fluoroscopic images compared with conventional fluoroscopy (P<0.05). No significant difference in overall procedure time (P=0.96) or drilling quality (P=0.12) was detected. VAF demonstrated improvement in radiation exposure when used by a less experienced surgeon (P<0.05). VAF is a feasible technique for distal interlocking. Overlaid visualization of the osseous anatomy in relation to the surgical field of view appears to improve surgeons' perception of relevant structures and their spatial orientation for the use of surgical instruments.

Cyclic and Load-to-Failure Properties of All-Suture Anchors in Human Cadaveric Shoulder Glenoid Bone

To evaluate the cyclic displacement and ultimate load to failure of 4 all-suture anchors in human cadaveric shoulder glenoid bone. Four all-suture anchors indicated for glenoid labral repair were tested in 14 matched pairs of human cadaveric fresh-frozen glenoids. Anchors were inserted at 4 different locations for a total of 112 tests (12-, 3-, 6-, and 9-o'clock positions for right glenoids). Cyclic loading (10 to 60N at 1Hz for 200 cycles) and single pull-to-failure testing (33mm/s) were performed. A Kruskal-Wallis 1-way analysis of variance with the Dunn multiple-comparison post hoc test was used for statistical analysis. One matched pair was excluded because of poor bone quality. Thus, 13 matched pairs were included in the study, and a total of 104 tests were performed. The Q-Fix anchors showed significantly less displacement after 100 cycles (mean ± standard deviation, 1.40 ± 0.97mm; P < .001) and 200 cycles (1.53 ± 1.00mm, P < .001) than all other anchors tested. The Q-Fix (191.3 ± 65.8N), Suturefix (188.3 ± 61.4N), and JuggerKnot (183.6 ± 63.5N) anchors had significantly greater ultimate loads to failure than the Iconix anchors (143.5 ± 54.1N)(P= .01, P= .012, and P= .021, respectively). Displacement greater than 5mm occurred in 6 Iconix anchors (22.1%), 5 Suturefix anchors (19.2%), 4 JuggerKnot anchors (15.4%), and 0 Q-Fix anchors (0%). The Q-Fix anchors showed less displacement with cyclic loading than the Iconix, JuggerKnot, and Suturefix anchors. The Iconix anchors had a lower ultimate load to failure than the Q-Fix, Suturefix, and JuggerKnot anchors. Only the Q-Fix group had no anchors displace greater than 5mm with cyclic loading. All-suture anchors vary in their deployment mechanism, which may alter their strength and performance. Operators must be aware of these anchors' propensity to displace while deploying them.

The condylar canal and emissary vein-a comprehensive and pictorial review of its anatomy and variation.

The condylar canal and its associated emissary vein serve as vital landmarks during surgical interventions involving skull base surgery. The condylar canal serves to function as a bridge of communication from the intracranial to extracranial space. Variations of the condylar canal are extremely prevalent and can present as either bilateral, unilateral, or completely absent. Anatomical variations of the condylar canal pose as a potential risk to surgeons and radiologist during diagnosis as it could be misinterpreted for a glomus jugular tumor and require surgical intervention when one is not needed. Few literature reviews have articulated the condylar canal and its associated emissary vein through extensive imaging. This present paper aims to further the knowledge of anatomical variations and surgical anatomy involving the condylar canal through high-quality computed tomography (CT) images with cadaveric and dry bone specimens that have been injected with latex to highlight emissary veins arising from the condylar canal.

Transplant of Adult Bone for Reconstruction of a Large Post-Traumatic Cranial Defect in a Very Young Baby

Large cranial defects in very young patients are challenging. The ideal material for cranioplasty in this age group has not yet been identified. Cryopreserved autologous bone presents very high rates of failures, acrylic resins pose a number of compatibility problems, bioceramics may be contraindicated, and autografts may be not adequate for repair of large defects. We present an 18-month-old baby with a large post-traumatic cranial defect which was repaired by assembling a new bone flap on a sterile stereolithographic 3-D model. This customized newly assembled flap consisted of a scaffold of autologous bone (from vault duplication) sustaining 2 large grafts of homologous cadaveric bone. It was adequately modeled and contoured on the 3-D model using metallic plates and screws. Immediately after implantation on the skull, the metallic devices were progressively replaced by reabsorbable material, thus maintaining the previously obtained flap profile. In this paper we detail this original technique which was developed to manage this specific patient.

Three-dimensional study of vestibular anatomy as it relates to the stapes footplate and its clinical implications: an augmented reality development.

The anatomy of the membranous labyrinth within the vestibule has direct implications for surgical intervention. The anatomy of the otoliths has been studied, but there is limited information regarding their supporting connective tissue structures such as the membrana limitans in humans. One guinea pig and 17 cadaveric human temporal bones were scanned using micro computed tomography, after staining with 2 per cent osmium tetroxide and preservation with Karnovsky's solution, with a resolution from 1 µm to 55 µm. The data were analysed using VGStudio Max software, rendered in three-dimensions and published in augmented reality. In 50 per cent of ears, the membrana limitans attached directly to the postero-superior part of the stapes footplate. If attachments were present in one ear, they were present bilaterally in 100 per cent of cases. Micro computed tomography imaging allowed three-dimensional assessment of the inner ear. Such assessments are important as they influence the surgical intervention and the evolution of future innovations.

Manipulating the Amount and Structure of the Organic Matrix Affects the Water Compartments of Human Cortical Bone.

Being predictors of the mechanical properties of human cortical bone, bound and pore water measurements by magnetic resonance (MR) imaging are being developed for the clinical assessment of fracture risk. While pore water is a surrogate of cortical bone porosity, the determinants of bound water are unknown. Manipulation of organic matrix properties by oxidative deproteinization, thermal denaturation, or nonenzymatic glycation lowers bone toughness. Because bound water contributes to bone toughness, we hypothesized that each of these matrix manipulations affect bound water fraction (Vbw/Vbone). Immersing cadaveric bone samples in sodium hypochlorite (NaClO) for 96 hours did not affect tissue mineral density or cortical porosity, but rather decreased Vbw/Vbone and increased short‐T2 pore water signals as determined by 1H nuclear MR relaxometry (1H NMR). Moreover, the post treatment Vbw/Vbone linearly correlated with the remaining weight fraction of the organic matrix. Heating bone samples at 110°C, 120°C, 130°C, and then 140°C (∼24 hours per temperature and rehydration for ∼24 hours before 1H NMR analysis) did not affect Vbw/Vbone. After subsequently heating them at 200°C, Vbw/Vbone increased. Boiling bone samples followed by heating at 110°C, 120°C, and then 130°C in water under pressure (8 hours per temperature) had a similar effect on Vbw/Vbone. Raman spectroscopy analysis confirmed that the increase in Vbw/Vbone coincided with an increase in an Amide I subpeak ratio that is sensitive to changes in the helical structure of collagen I. Glycation of bone by ribose for 4 weeks, but not in glucose for 16 weeks, decreased Vbw/Vbone, although the effect was less pronounced than that of oxidative deproteinization or thermal denaturation. We propose that MR measurements of bound water reflect the amount of bone organic matrix and can be modulated by collagen I helicity and by sugar‐derived post translational modifications of the matrix. © 2019 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

Assessment of the Integrity of Adult Human Mandibular Angle

The purpose of this study was to analyze the integrity of the adult human mandibular angle. The left hemimandibles of 24 human cadavers were selected and divided into three groups based upon remaining dental status. The height of the left mandibular body was measured. Hemimandibles were mounted in acrylic bone cement at the mandibular condyle. The left mounted hemimandibles were secured into an Instron 5565 mechanical unit and the occlusal plane was sequentially loaded until fracture of the mandibular bone occurred. Minimum, maximum, mean, and standard deviations for compressive force as well as displacement of the occlusal plane were derived and compared for descriptive statistics. The correlations between the gender, mandibular body height, and maximal load were examined. The mean mandibular heights among males and females were 22.44 mm and 17.53 mm, respectively. Results portrayed a significant correlation between gender and mandibular height. The mean maximal loads among males and females were 1,174.17 and 828.14 N, respectively. Results portrayed a statistically significant difference between males and females regarding maximum load as well as the height of the mandible ( p=0.0103 and p=0.0067, respectively). No statistically significant association between maximum load and dental status (presence/absence of molar teeth) was found ( p &gt; 0.05). The maximal load of human mandibular angle was found to be higher than that of the heavily investigated polyurethane synthetic mandible replica. The average height of the mandibular body in males was found to be greater than that of females. Mandibular body height showed a direct correlation to maximal load of the hemimandibular angle. In maxillofacial research, biomechanical evaluations of mandibular angle fractures and plating techniques with human cadaveric bone should be considered alongside or in place of conventional synthetic polyurethane mandibles.