Main 3D Manufacturing Techniques for Customized Bone Substitutes. A Systematic Review.

Clinicians should be aware of the main methods and materials to face the challenge of bone shortage by manufacturing customized grafts, in order to repair defects. This study aims to carry out a bibliographic review of the existing methods to manufacture customized bone scaffolds through 3D technology and to identify their current situation based on the published papers. A literature search was carried out using "3D scaffold", "bone regeneration", "robocasting" and "3D printing" as descriptors. This search strategy was performed on PubMed (MEDLINE), Scopus and Cochrane Library, but also by hand search in relevant journals and throughout the selected papers. All the papers focusing on techniques for manufacturing customized bone scaffolds were reviewed. The 62 articles identified described 14 techniques (4 subtraction + 10 addition techniques). Scaffold fabrication techniques can be also be classified according to the time at which they are developed, into Conventional techniques and Solid Freeform Fabrication techniques. The conventional techniques are unable to control the architecture of the pore and the pore interconnection. However, current Solid Freeform Fabrication techniques allow individualizing and generating complex geometries of porosity. To conclude, currently SLA (Stereolithography), Robocasting and FDM (Fused deposition modeling) are promising options in customized bone regeneration.

Birmingham mid-head resection periprosthetic fractures: Case report.

INTRODUCTION: Total hip arthroplasty in young patients can cause problems when it comes to choosing a suitable implant. The Birmingham Mid-Head Resection prosthesis (BMHR) offers the option of preserving bone stock despite its poor quality in the femoral neck. Femoral neck fractures are a known complication of hip resurfacing prostheses and the main reason for revision surgery. Retaining the femoral implant may cause difficulties in osteosynthesis carried out with implants habitually used for intertrochanteric or femoral neck fractures (e.g., a screw-plate device or a cephalomedullary nail) [2]. PRESENTATION OF CASE: We present the case of an 81-year-old patient who underwent surgery for right hip osteoarthritis and received a Birmingham Mid-Head Resection prosthesis. She had no history of previous fractures due to frailty. While on holiday, she sustained a periprosthetic fracture as a result of a fall. While the most common fracture in resurfacing prosthesis is produced in the femoral neck, in this case the patient sustained a subtrochanteric fracture. This fracture was surgically treated by means of open reduction and internal fixation with trochanteric plate and three cerclages. DISCUSSION: Olsen et al. [8] described two fracture patterns: transcervical vertical shear type and subcapital type. In our patient's case, the fracture pattern was different to those described, as the fracture started in the cervical area and reached the subtrochanteric area. This change in the standard periprosthetic fracture pattern leads to a change in the therapeutic attitude that must be adopted. CONCLUSION: BMHR prostheses are metal-on-metal implants that resulted from the development of the standard resurfacing prostheses used to treat hip osteoarthritis in young patients with the goal of preserving as much bone stock as possible. In this paper we will describe a rare complication in this type of prosthesis and how it was surgically treated after reviewing the available literature.

Cold abscess of the chest wall: A diagnostic challenge.

Tuberculosis of the chest wall represents less than 5% of cases of musculoskeletal tuberculosis. We present the case of a patient with a cold abscess in the pectoral region due to Mycobacterium tuberculosis. A 29-year-old male of Senegalese origin reported a progressive increase in size of the right hemi-thorax without trauma or previous effort. A liquid collection of 14cm on the major axis, between the pectoralis major muscle and the costal wall, was demonstrated on magnetic resonance imaging. Surgical debridement revealed a marked granulomatous inflammatory reaction with focal necrosis; PCR was positive for M. tuberculosis complex and culture subsequently grew M. tuberculosis complex. Specific treatment for tuberculosis achieved a good clinical outcome. The diagnosis of tuberculosis of the chest wall is always difficult, being a clinical challenge.

Human Bone Marrow Mesenchymal Stromal Cells Promote Bone Regeneration in a Xenogeneic Rabbit Model: A Preclinical Study.

Significant research efforts have been undertaken during the last decades to treat musculoskeletal disorders and improve patient's mobility and quality of life. The goal is the return of function as quickly and completely as possible. Cellular therapy has been increasingly employed in this setting. The design of this study was focused on cell-based alternatives. The present study aimed at investigating the bone regeneration capacity of xenogeneic human bone marrow-derived mesenchymal stromal cell (hMSC) implantation with tricalcium phosphate (TCP) granules in an immunocompetent rabbit model of critical-size bone defects at the femoral condyles. Two experimental groups, TCP and hMSC + TCP, were compared. Combination of TCP and hMSC did not affect cell viability or osteogenic differentiation. We also observed significantly higher bone regeneration in vivo in the hMSC + TCP group, which also displayed better TCP osteointegration. Also, evidence of hMSC contribution to a better TCP osteointegration was noticed. Finally, no inflammatory reaction was detected, besides the xenotransplantation of human cells into an immunocompetent recipient. In summary, hMSC combined with TCP granules is a potential combination for bone regeneration purposes that provides better preclinical results compared to TCP alone.

Cauda equina syndrome during pregnancy: A condition to consider.

INTRODUCTION: Low back pain is a common cause of medical consultation during pregnancy and usually supposes a non-malignant prognostic. PRESENTATION OF CASES: We report two cases of pregnant women whom suffered cauda equina syndrome during pregnancy and underwent emergency surgery after the birth of their babies. DISCUSSION: MRI is the main diagnosis method for cauda equina even during pregnancy. Modern obstetric practice asks surgeons to perform surgery under safe conditions at all gestation stages. Surgical decompression reports better prognosis when practiced within the first 48 h after the onset of saddle hypoesthesia. CONCLUSION: When CES is suspected, after MRI study, emergency surgery is the only solution to improve the condition of these patients.

Giant-cell tumor of the rib cage extending to the spine : Case report.

PURPOSE: We present the case of a patient with a giant cell tumor of the thoracic wall that invaded the thoracic spine. MATERIAL AND METHODS: A giant cell tumor that affects the spine and the thoracic wall is very rare but can grow to a large size. We report a case of giant cell tumor of the left chest wall extending to the thoracic spine in a 28-year-old man. Positron emission tomography (PET) showed a tumor of 11â€¯× 4â€¯× 13 cm in size and the histopathology specimen of the first surgical procedure diagnosed a giant cell tumor. The tumor was treated by oblique osteotomy guided with pedicle wires. RESULTS: A giant cell tumor was histologically confirmed following radical surgery. After 1 year of follow-up the patient was asymptomatic. There has been no recurrence of the tumor. CONCLUSION: The use of transpedicular Kirschner wires could be a good technical support for transpedicular oblique sagittal osteotomy.

Regeneration of hyaline cartilage promoted by xenogeneic mesenchymal stromal cells embedded within elastin-like recombinamer-based bioactive hydrogels.

Over the last decades, novel therapeutic tools for osteochondral regeneration have arisen from the combination of mesenchymal stromal cells (MSCs) and highly specialized smart biomaterials, such as hydrogel-forming elastin-like recombinamers (ELRs), which could serve as cell-carriers. Herein, we evaluate the delivery of xenogeneic human MSCs (hMSCs) within an injectable ELR-based hydrogel carrier for osteochondral regeneration in rabbits. First, a critical-size osteochondral defect was created in the femora of the animals and subsequently filled with the ELR-based hydrogel alone or with embedded hMSCs. Regeneration outcomes were evaluated after three months by gross assessment, magnetic resonance imaging and computed tomography, showing complete filling of the defect and the de novo formation of hyaline-like cartilage and subchondral bone in the hMSC-treated knees. Furthermore, histological sectioning and staining of every sample confirmed regeneration of the full cartilage thickness and early subchondral bone repair, which was more similar to the native cartilage in the case of the cell-loaded ELR-based hydrogel. Overall histological differences between the two groups were assessed semi-quantitatively using the Wakitani scale and found to be statistically significant (p < 0.05). Immunofluorescence against a human mitochondrial antibody three months post-implantation showed that the hMSCs were integrated into the de novo formed tissue, thus suggesting their ability to overcome the interspecies barrier. Hence, we conclude that the use of xenogeneic MSCs embedded in an ELR-based hydrogel leads to the successful regeneration of hyaline cartilage in osteochondral lesions.

Finite element analysis and cadaveric cinematic analysis of fixation options for anteriorly implanted trabecular metal interbody cages.

PURPOSE: To assess, with finite element analysis and an in vitro biomechanical study in cadaver, whether the implementation of an anterior interbody cage made of hedrocel with nitinol shape memory staples in compression increases the stiffness of the stand-alone interbody cage and to compare these constructs' stiffness to other constructs common in clinical practice. METHODS: A biomechanical study with a finite element analysis and cadaveric testing assessed the stiffness of different fixation modes for the L4-L5 functional spinal unit: intact spine, destabilized spine with discectomy, posterior pedicle-screw fixation, anterior stand-alone interbody cage, anterior interbody cage with bilateral pedicle screws and anterior interbody cage with two shape memory staples in compression. These modalities of vertebral fixation were compared in four loading modes (flexion, extension, lateral bending, and axial rotation). RESULTS: The L4-L5 spinal unit with an anterior interbody cage and two staples was stiffer than the stand-alone cage. The construct stiffness was similar to that of a model of posterior pedicular stabilization. The stiffness was lower than that of the anterior cage plus bilateral pedicle-screw fixation. CONCLUSION: The use of an anterior interbody implant with shape memory staples in compression may be an alternative to isolated posterior fixation and to anterior isolated implants, with increased stiffness.