Research progress on the biological modifications of implant materials in 3D printed intervertebral fusion cages.

Anterior spine decompression and reconstruction with bone grafts and fusion is a routine spinal surgery. The intervertebral fusion cage can maintain intervertebral height and provide a bone graft window. Titanium fusion cages are the most widely used metal material in spinal clinical applications. However, there is a certain incidence of complications in clinical follow-ups, such as pseudoarticulation formation and implant displacement due to nonfusion of bone grafts in the cage. With the deepening research on metal materials, the properties of these materials have been developed from being biologically inert to having biological activity and biological functionalization, promoting adhesion, cell differentiation, and bone fusion. In addition, 3D printing, thin-film, active biological material, and 4D bioprinting technology are also being used in the biofunctionalization and intelligent advanced manufacturing processes of implant devices in the spine. This review focuses on the biofunctionalization of implant materials in 3D printed intervertebral fusion cages. The surface modifications of implant materials in metal endoscopy, material biocompatibility, and bioactive functionalizationare summarized. Furthermore, the prospects and challenges of the biofunctionalization of implant materials in spinal surgery are discussed. Fig.a.b.c.d.e.f.g As a pre-selected image for the cover, I really look forward to being selected. Special thanks to you for your comments.

The Masquelet Technique: Can Disposable Polypropylene Syringes be an Alternative to Standard PMMA Spacers? A Rat Bone Defect Model.

BACKGROUND: Usually, the two-stage Masquelet induced-membrane technique for extremity reconstruction begins with a polymethylmethacrylate (PMMA) cement spacer-driven membrane, followed by an autologous cancellous bone graft implanted into the membrane cavity to promote healing of large bone defects. In exceptional cases, spacers made of polypropylene disposable syringes were successfully used instead of the usual PMMA spacers because of a PMMA cement shortage caused by a lack of resources. However, this approach lacks clinical evidence and requires experimental validation before being recommended as an alternative to the conventional technique. QUESTIONS/PURPOSES: To (1) develop and (2) validate a critical-sized femoral defect model in rats for two stages of the Masquelet technique and to (3) compare the biological and bone healing properties of polypropylene-induced membranes and PMMA-induced membranes in this model. METHODS: Fifty male Sprague Dawley rats aged 8 weeks old received a 6-mm femur defect, which was stabilized with an external fixator that was converted into an internal device. In the development phase, the defect was filled with PMMA in 16 rats to determine the most favorable timing for bone grafting. Two rats were excluded since they died of anesthetic complications. The other 14 were successively euthanized after 2 weeks (n = 3), 4 weeks (n = 4), 6 weeks (n = 4), and 8 weeks (n = 3) for induced membrane analyses. In the validation phase, 12 rats underwent both stages of the procedure using a PMMA spacer and were randomly assigned to two groups, whether the induced membrane was preserved or removed before grafting. To address our final objective, we implanted either polypropylene or PMMA spacers into the defect (Masquelet technique Stage 1; n = 11 rats per group) for the period established by the development phase. In each group, 6 of 11 rats were euthanized to compare the biological properties of polypropylene-induced membranes and PMMA-induced membranes using histological qualitative analysis, semiquantitative assessment of the bone morphogenic protein-2 content by immunostaining, and qualitative assessment of the mesenchymal stromal cell (MSC; CD31-, CD45-, CD90+, and CD73+ phenotypes) content by flow cytometry. Quantitative measurements from serum bone turnover markers were also performed. The five remaining rats of each group were used for Masquelet technique Stage 2, in which rat bone allografts were implanted in the induced membrane cavity after the polypropylene or PMMA spacers were removed. These rats recovered for 10 weeks before being euthanized for microCT quantitative measurements and bone histology qualitative assessment to evaluate and compare the extent of bone regeneration between groups. RESULTS: Induced membrane analyses together with serum bone turnover measurements indicated that a 4-week interval time between stages was the most favorable. Removal of the induced membrane before grafting led to almost constant early implant failures with poor bone formation. Four-week-old rats with polypropylene-triggered induced membranes displayed similar histologic organization as rats with PMMA-driven induced membranes, without any difference in the cell density of the extracellular matrix (4933 ± 916 cells per mm2 for polypropylene versus 4923 ± 1284 cells per mm2 for PMMA; p = 0.98). Induced membrane-derived MSCs were found in both groups with no difference (4 of 5 with polypropylene versus 3 of 3 with PMMA; p > 0.99). Induced membrane bone morphogenic protein-2 immunolabeling and serum bone turnover marker levels were comparable between the polypropylene and PMMA groups. MicroCT analysis found that bone regeneration in the polypropylene group seemed comparable with that in the PMMA group (29 ± 26 mm3 for polypropylene versus 24 ± 18 mm3 for PMMA; p > 0.99). Finally, qualitative histological assessment revealed a satisfactory endochondral ossification maturation in both groups. CONCLUSION: Using a critical-sized femoral defect model in rats, we demonstrated that polypropylene spacers could induce membrane encapsulation with histologic characteristics and bone regenerative capacities that seem like those of PMMA spacers. CLINICAL RELEVANCE: In a same bone site, polymers with close physical properties seem to lead to similar foreign body reactions and induce encapsulating membranes with comparable bone healing properties. Polypropylene spacers made from disposable syringes could be a valuable alternative to PMMA. These results support the possibility of a cementless Masquelet technique in cases of PMMA shortage caused by a lack of resources.

Development and physicochemical characterization of novel porous phosphate glass bone graft substitute and in vitro comparison with xenograft.

The process of bone regeneration in bone grafting procedures is greatly influenced by the physicochemical properties of the bone graft substitute. In this study, porous phosphate glass (PPG) morsels were developed and their physicochemical properties such as degradation, crystallinity, organic content, surface topography, particle size and porosity were evaluated using various analytical methods. The in vitro cytotoxicity of the PPG morsels was assessed and the interaction of the PPG morsels with Dental Pulp Stem Cells (DPSCs) was studied by measuring cell proliferation and cell penetration depth. The cell-material interactions between PPG morsels and a commercially available xenograft (XG) were compared. The PPG morsels were observed to be amorphous, biocompatible and highly porous (porosity = 58.45%). From in vitro experiments, PPG morsels were observed to be non-cytotoxic and showed better cell proliferation. The internal surface of PPG was easily accessible to the cells compared to XG.

Comparison of biomechanical performance of single-level triangular and quadrilateral profile anterior cervical plates.

The quadrilateral anterior cervical plate (ACP) is used extensively in anterior cervical discectomy and fusion (ACDF) to reconstruct the stability of the cervical spine and prevent cage subsidence. However, there have been no comparison studies on the biomechanical performance of quadrilateral ACP and triangular ACP. The objective of this study is to investigate the functional outcomes of quadrilateral ACP and triangular ACP usage in ACDF surgery. In this study, a finite element model of intact C1-C7 segments was established and verified. Additionally, two implant systems were built; one using triangle anterior cervical plates (TACP) and another using quadrilateral orion anterior cervical plate (QACP). Both models were then compared in terms of their postoperative biomechanical performance, under normal and excessive motion. Compared to QACP, the peak stress of the TACP screws and plates occurred at 359.2 MPa and 97.2 MPa respectively and were the highest during over extension exercises. Alternately, compared to TACP, the endplate peak stress and the cage displacement of QACP were the largest at over extension, with values of 7.5 MPa and 1.2 mm, respectively. Finally, the average stress ratio of bone grafts in TACP was relatively high at 31.6%. In terms of biomechanical performance, TACP can share the load more flexibly and reduce the risks of cage subsidence and slippage but the screws have high peak stress value, thereby increasing the risk of screw slippage and fracture. This disadvantage must be considered when designing a TACP based implant for a potential patient.

What Is the Survival of the Telescope Allograft Technique to Augment a Short Proximal Femur Segment in Children After Resection and Distal Femur Endoprosthesis Reconstruction for a Bone Sarcoma?

BACKGROUND: Large, malignant bone tumors and revision limb salvage procedures often result in the resection of extensive lengths of the involved bone segment, leaving a residual segment of bone that may be too short to support a standard intramedullary stem for endoprosthetic reconstruction. Telescope allografting, in which an allograft is used to augment the remaining bone segment by telescoping it into the residual bone segment, was described for situations in which residual bone stock is insufficient after tumor resection or prosthetic revision. Apart from one study that first described the procedure [15], there are no other studies reporting the outcome of this telescopic concept for restoring bone stock. QUESTIONS/PURPOSES: For patients younger than 18 years who underwent the telescopic allograft technique to augment a short segment of the proximal femur after resection of bone sarcomas who also underwent endoprosthesis reconstruction of the distal femur, we asked: (1) What is the survivorship free from removal of the telescopic allograft and the endoprosthetic stem at 7 years after surgery? (2) What proportion of these reconstructions will heal to the host bone without delayed union or nonunion? (3) What is the functional outcome based on the Musculoskeletal Tumor Society (MSTS) score? METHODS: We retrospectively studied our institutional database and identified 127 patients younger than 18 years who underwent surgery for a primary malignant bone tumor of the distal femur between December 2008 and October 2018. After excluding 16 patients undergoing amputation and rotationplasty and 57 patients undergoing recycled autograft/allograft reconstruction, 54 patients who underwent primary or revision distal femur endoprosthesis reconstruction were identified. Among these patients, we considered 15 patients who underwent telescopic allograft augmentation of the femur for analysis. One patient was lost to follow-up before 2 years but was not known to have died, leaving 14 for analysis at a median (range) 49 months (24 to 136 months) of follow-up. The indications for telescopic allograft augmentation of the femur in our institution were a proximal femur length of less than 120 mm after resection or resection of more than two-thirds of the total length of the femur. Ten of 14 patients underwent telescopic allograft augmentation as a revision procedure (distal femur resorption in five patients, endoprosthesis stem loosening in three patients, implant fracture in one patient, and infection in one patient), and the remaining four patients underwent telescopic allograft augmentation as a primary limb salvage procedure for large malignant bone tumors of the distal femur. The histologic diagnosis in all patients was osteosarcoma. At the time of telescopic allograft augmentation and reconstruction, the median age of the patients was 14 years (7 to 18 years). The size and the type of bone allograft to be used (femoral shaft or proximal femur) was planned before surgery, with consideration of the extent of resection, level of osteotomy, diameter of the host bone at the osteotomy site, and approximate diameter of the endoprosthesis stem to be used. The segment of the cylindrical allograft used for telescoping was thoroughly washed, prepared, and impacted onto the native femur to achieve telescoping and overlap. Serial digital radiographs were performed once a month for the first 6 months after the procedure, every 2 months until 1 year, and then every 6 months thereafter. Two surgeons in the department (at least one of which was involved in the surgery) retrieved and reviewed clinical notes and radiographs to determine the status of the telescopic allograft and endoprosthesis stem. We defined delayed union as radiological union at the osteotomy site more than 6 months after the procedure without additional surgery; we defined nonunion as no radiological evidence of callus formation at the osteotomy site 9 months after the procedure, necessitating additional surgery. The reviewers did not disagree about the definition of healing time. None of the patients missed radiographic follow-up. Kaplan-Meier survivorship free from removal of telescopic allograft and the endoprosthesis stem at 7 years after surgery was estimated. Patient function was assessed using the 1993 version of the MSTS [9], as determined by chart review of the institutional database performed by one of the surgeons from the department. RESULTS: The survivorship free from removal of the telescopic allograft and endoprosthesis stem at 7 years after surgery was 80% (95% confidence interval 22% to 96%). The allograft united with the host bone in 100% (14 of 14) of the patients. Though 21% (3 of 14) had delayed union, no nonunions were seen. The median (range) MSTS score at the final follow-up interval was 27 (22 to 30). CONCLUSION: Although this is a small group of patients, we believe that allograft segments help augment short bone stock of the proximal femur after long-segment resections, and the telescopic technique seems to be associated with a low proportion of nonunion or delayed union, which is one of the most common complications of allografts. Maintaining an adequate length of the proximal femur is important in preserving the hip, and this technique may be especially useful for young individuals who may undergo repeated revision procedures. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Fibula Jaw-in-a-Day with Minimal Computer-Aided Design and Manufacturing: Maximizing Efficiency, Cost-Effectiveness, Intraoperative Flexibility, and Quality.

SUMMARY: The vascularized fibular flap has been the mainstay for mandibular reconstruction for over 30 years. Its latest evolutionary step is the jaw-in-a-day operation, during which the fibula flap and dental prosthesis restoration are performed in a single stage. Computer-aided design and manufacturing technology in mandibular reconstruction has gained popularity, as it simplifies the procedure and produces excellent outcomes. However, it is costly, time-consuming, and limited in cases that involve complex defects, including bone and soft-tissue coverage. Moreover, it does not allow for intraoperative changes in the surgical plan, including defect size and recipient vessel selection.The authors describe their approach, including a conventional technique for fibula osteoseptocutaneous flap harvest without the need for a premanufactured cutting guide, using bundled wooden tongue spatulas instead, a stereolithographic model to customize commercially ready-made reconstruction plates, and two pieces of resin to maintain occlusive alignment of the remaining jaw segments during mandibular osteotomy. Dental implants are inserted free-hand. Vector guides are then connected to the implants following insertion into the fibula to confirm acceptable alignment and subsequently replaced with scan sensors. An intraoperative digital scan is used to design and to produce a dental prosthesis by in-house milling of a polymethylmethacrylate block. From our 10-case experience over the past 3 years, we have found that our approach offers a reliable method that matches the excellent outcomes seen using full computer-assisted design and manufacturing technology. It is time- and cost-effective, not limited to relatively simple jaw defects, and can readily accommodate intraoperative changes of surgical plan.

Which one of the benign tumors and tumor-like lesions located in long bones needs prophylactic fixation during surgery?

OBJECTIVES: This study aims to define the simultaneous prophylactic fixation indications of benign tumors and tumor-like lesions located in long bones that were treated by curettage and grafting/cementing. PATIENTS AND METHODS: Fifty-six patients (33 males, 23 females; mean age 30.9±15.9; range, 15 to 65 years) who were treated by curettage and grafting or cementation for their benign tumors or tumor-like lesions in long bones between January 2013 and June 2016 were retrospectively analyzed. Age, sex, anamnesis and physical examination findings, histopathologic diagnosis, lesion localization, pre- and postoperative imaging results and follow-up data were all analyzed. The patients were divided into two groups as those with and without postoperative fracture. RESULTS: The most common localization was femur (38%). The mean tumor diameter was 6.8±2.2 (range, 2.6 to 12.6) cm and volume was 58.3±45.0 (range, 6 to 177) cm³. Postoperative fracture occurred in 14 patients. The lesion diameter and volume of the patients in postoperative fracture group were significantly higher compared to group without postoperative fracture (p=0.034 and p=0.004, respectively). A volume value greater than 67 cm³ and ages over 35 years were found to be associated with a higher rate of fracture for all lesions. CONCLUSION: In the postoperative period, patients with benign tumors or tumor-like lesions of long bones had a higher fracture risk if the volume value was greater than 67 cm³ and the age was over 35 years. Prophylactic fixation may be suggested for these patients.

The effect of synthetic bone graft substitutes on bone formation in rabbit calvarial defects.

The aim of this study was to evaluate the influence of the intensity of the biomimetic hydroxyapatite (HA) coating of α-tricalcium phosphate (α-TCP) on biomaterial degradation and bone formation. Twenty-four female NZW rabbits of approximately 12 weeks of age were used. Critical size defects were randomly treated with 3%:97% HA:α-TCP (BBCP1), 12%:88% HA:α-TCP (BBCP2), and 23%:77% HA:α-TCP (BBCP3), respectively or sham. All defects were covered with a resorbable collagen membrane. Animals were euthanized after 3 and 12 weeks of healing and samples were investigated by micro-CT and histologic analysis. Ingrowth of newly formed woven bone from the original bone at 3-week healing period was observed in all samples. At the 12-week healing period, the new bone in the peripheral area was mainly lamellar and in the central region composed of both woven and lamellar bone. New bony tissue was found on the surface of all three types of granules and at the interior of the BBCP1 granules. Samples with 3% HA showed significantly less residual biomaterial in comparison to the other two groups. Furthermore, BBCP1 significantly promoted new bone area as compared to other three groups and more bone volume as compared to the control. Within its limitations, this study indicated the highest degradation rate in case of BBCP1 concomitant with the highest rate of bone formation. Hence, formation of new bone can be affected by the level of biomimetic HA coating of α-TCP.

Synthetic Bone Graft Substitute for Treatment of Unicameral Bone Cysts.

BACKGROUND: Treatments for unicameral bone cysts (UBCs) have high documented failure rates (27% to 63%) because of recurrence or persistence of the cyst, similar to nonoperative management. Recent evidence suggests that filling of the defect with a synthetic bone graft substitute (SBGS) supports the weakened cortex and promotes new bone growth. A calcium sulfate, brushite, calcium phosphate, composite graft material (PRODENSE, Wright Medical, Memphis, TN) has been evaluated as a substitute for autogenous or allogenous graft in animal and human studies. The purpose of this study was to compare the rates of revision surgery in patients treated for UBCs with an SBGS compared with historical treatments with allograft or autologous bone marrow aspirate. METHODS: The authors reviewed 27 of 33 patients (age, 6 months to 21 years) an average of 121 months (range, 32 to 228) after filling of a UBC with an injection of SBGS (n=18) versus allograft or autologous bone marrow aspirate (n=9) between June 2008 and December 2017. Six patients with no follow-up were excluded. Groups did not differ in age at surgery, sex (19/27 male), history of pathologic fracture (22/27), or previous treatments (11/27). The primary outcome was the rate of revision surgery. Secondary outcomes included revision surgery-free survival as evaluated by the log-rank test, rate of postoperative fracture, persistent cysts, continued pain, and/or growth disturbance at the final follow-up. RESULTS: Seven of 9 patients treated with allograft or autograft underwent revision surgery for postoperative pathologic fracture (n=2) or resorption of the graft (n=5) compared with 2 of 18 patients injected with the SBGS, both treated for graft resorption. The use of SBGS was associated with a decreased need for revision surgery over all time periods (hazard ratio, 0.14; 95% confidence interval, 0.03-0.05). There was no significant difference between postoperative fracture (2/18 vs. 2/9), persistent cyst (7/18 vs. 5/9), pain (0/18 vs. 2/9), or growth disturbance (1/18 vs. 3/9). CONCLUSIONS: Treatment of UBCs with SBGS may decrease reoperation rates. Initial radiographic appearance after SBGS treatment shows solid structural support, followed by new bone formation. This appearance may lead to a less aggressive approach in considering revision surgery. LEVEL OF EVIDENCE: Level III-retrospective comparative study investigating the results of treatment.

Simultaneous Perio-endo Surgery with ER:YAG Laser and Bone Xenograft. A Case Report.

Periodontally affected teeth with periapical lesion indicated for periapical surgery have a poor prognosis. Using Er:YAG lasers to perform simultaneous surgery on both defects may increase their survival rate. Preparing a retrograde cavity on affected teeth and obturating it is still a matter of debate among clinicians. The purpose of this case report was to describe the simultaneous use of Erbium-doped Yttrium Aluminium Garnet Er:YAG (2,940 nm) laser in the treatment of periapical granuloma and infraossal defect and the achieved results. The Er:YAG laser was used to perform flap dissection, granulation tissue removal, osteotomy and root-end resection except for initial flap incision and reflection. The cystic cavity was filled with Bio-Oss Collagen® xenograft. Results were followed up for 18 months with the help of radiographic orthopantomographic images. The outcome of this clinical case indicates that the use of Er:YAG laser could be considered a suitable method to perform simultaneous periodontal and endodontic surgery.

Long-term results of osteochondral autograft transplantation of the talus with a novel groove malleolar osteotomy technique.

OBJECTIVES: This study aims to evaluate the long-term results of osteochondral autograft transfer (OAT) of talar lesions performed using a modified osteotomy technique. PATIENTS AND METHODS: This retrospective study included 20 consecutive patients (11 males, 9 females; mean age 33.5±11 years; range, 15 to 56 years) (21 ankles) with osteochondral lesions of the talus (OLT) treated with the OAT system between August 2002 and October 2008. We performed a modified sulcus groove osteotomy, which provides better exposure of medial and central lesions. After a minimum duration of 10 years following surgery, patients' clinical functions were evaluated according to the American Orthopaedic Foot and Ankle Society (AOFAS) ankle- hindfoot scale and visual analog scale (VAS). The Tegner-Lysholm scoring system was used to determine the levels of knee activity. RESULTS: The mean follow-up period was 143.5 (range, 120 to 186) months. The mean AOFAS scores significantly improved from 60.4±7.4 (range, 48 to 70) preoperatively to 86.2±9.2 (range, 60 to 94) at the last follow-up (p≤0.05). The mean ankle VAS score significantly decreased from 6.3±0.4 (range, 5 to 7) preoperatively to 2.0±1.4 (range, 0 to 4). The mean Tegner-Lysholm score for this group was 89.7±11.7 (range, 68 to 100). Revision surgery was performed in only two patients because of impingement and arthritis. Recurrent knee pain at the donor site of the osteochondral autograft was observed in three (14%) patients. CONCLUSION: In the present study, good to excellent results were obtained in the treatment of OLT with OAT for a minimum follow-up duration of 10 years. This novel technique can also simplify the steep learning curve, which is challenging for surgeons.

Use of three-dimensionally printed ß-tricalcium phosphate synthetic bone graft combined with recombinant human bone morphogenic protein-2 to treat a severe radial atrophic nonunion in a Yorkshire terrier.

OBJECTIVE: To describe a novel surgical approach to treat a critical-sized bone defect due to severe, radial atrophic nonunion in a miniature dog. STUDY DESIGN: Case report ANIMAL: A 1-year-old Yorkshire terrier with a critical-sized left radial defect after failed internal fixation of a transverse radial fracture. METHODS: Computed tomographic (CT) images of the radius were imported for three-dimensional (3D) printing of a custom-designed synthetic 3D-printed ß-tricalcium phosphate (ß-TCP) scaffold. The radius was exposed, and the ß-TCP scaffold was press-fitted in the bone gap underneath the plate. Recombinant human bone morphogenic protein-2 (RhBMP-2) collagen sponges were squeezed to soak the scaffold with growth factor and then placed on both sides of the synthetic graft. Two additional cortical screws were also placed prior to routine closure of the surgical site. RESULTS: Radiographic examination was consistent with complete healing of the radius defect 4 months after surgery. The bone plate was removed 10 months after surgery. According to CT examination 18 months after surgery, there was no evidence of the synthetic graft; instead, complete corticalization of the affected area was noted. Complete functional recovery was observed until the last clinical follow-up 36 months postoperatively. CONCLUSION: Screw fixation and use of a 3D-printed ceramic scaffold augmented with rhBMP-2 resulted in excellent bone regeneration of the nonunion and full recovery of a miniature breed dog. CLINICAL SIGNIFICANCE: The therapeutic approach used in this dog could be considered as an option for treatment of large-bone defects in veterinary orthopedics, especially for defects affecting the distal radius of miniature dogs.

Effects of focal metallic implants on opposing cartilage - an in-vitro study with an abrasion test machine.

BACKGROUND: For focal cartilage defects, biological repair might be ineffective in patients over 45 years. A focal metallic implant (FMI) (Hemi-CAP Arthrosurface Inc., Franklin, MA, USA) was designed to reduce symptoms. The aim of this study was to evaluate the effects of a FMI on the opposing tibial cartilage in a biomechanical set-up. It is hypothesized that a FMI would not damage the opposing cartilage under physiological loading conditions. METHODS: An abrasion machine was used to test the effects of cyclic loading on osteochondral plugs. The machine applied a compressive load of 33 N and sheared the samples 10 mm in the anteroposterior direction by 1 Hz. Tibial osteochondral plugs from porcine knees were placed in opposition to a FMI and cycled for 1 or 6 h. After testing each plug was fixed, stained and evaluated for cartilage damage. RESULTS: After 1 h of loading (n = 6), none of the osteochondral plugs showed histologic signs of degradation. After 6 h of loading (n = 6) three samples had histologic signs of injury in the tangential zone (grade 1) and one had signs of injury in the transitional and deep zones (grade 2). Exploration for 6 h resulted in significant more cartilage damage compared to the shorter exploration time (p = 0.06). However, no significant difference between saline and hyaluronic acid was evident (p = 0.55). CONCLUSION: Under physiologic loading conditions, contact with a FMI leads to cartilage damage in the opposing articular cartilage in six hours. In clinical practice, a thorough analysis of pre-existing defects on the opposing cartilage is recommended when FMI is considered.

All-fiber optic displacement sensing system for an Ilizarov transverse tibial bone transport device.

A single-mode-multimode-single-mode (SMS) optical fiber-based displacement sensing system mounted on an Ilizarov transverse tibial bone transport device for microcirculation reconstruction is reported. Wide-range displacement is approximated as a uniform extension of a spring that is connected to an SMS optical fiber structure acting as the displacement sensor and allowing full displacement characterization. Transmission spectrum changes are measured, providing a displacement range of 24 mm with a sensitivity of $ - {55.42}\;{\rm pm/mm}$-55.42pm/mm and a resolution of 45.2 µm. The experimental results are characterized using a polynomial response curve for measuring the displacement due to transverse distraction of the Ilizarov device. The SMS fiber interrogation system is based on a macrobending fiber edge filter-based ratiometric measurement system. The use of SMS fibers together with the macrobending fiber-based interrogation system eliminates the influence of temperature on the displacement measurement. The implementation of the all-fiber sensing system of this investigation has uniquely facilitated a smart clinical device with a wide displacement range as well as operating in real-time monitoring when attached to the Ilizarov transverse tibial bone transport device. It also means that this fiber-optic sensing device can be made more cost-effective, simpler in construction, and more versatile while providing a high degree of measurement accuracy and resolution.

Minimizing risk of customized titanium mesh exposures - a retrospective analysis.

BACKGROUND: Recommendations for soft tissue management associated with customized bone regeneration should be developed. The aim of this study was to evaluate a new protocol for customized bone augmentation in a digital workflow. METHODS: The investigators implemented a treatment of three-dimensional bone defects based on a customized titanium mesh (Yxoss CBR®, ReOSS, Filderstadt, Germany). Patients and augmentation sites were retrospectively analysed focussing on defect regions, demographic factors, healing difficulties and potential risk factors. An exposure rate was investigated concerning surgical splint application, A®- PRF and flap design. RESULTS: In total, 98 implants could be placed. Yxoss CBR® was removed after mean time of 6.53 ± 2.7 months. Flap design was performed as full flap preparation (27.9%), full flap and periosteal incision (39.7%), periosteal incision (1.5%), poncho/split flap (27.9%) and rotation flap (2.9%). In 25% of the cases, exposures of the meshes were documented. Within this exposure rate, most of them were slight and only punctual (A = 16.2%), like one tooth width (B = 1.5%) and complete (C = 7.4%). A®- PRF provided significantly less exposures of the titanium meshes (76.5% no exposure vs. 23.5% yes, p = 0.029). Other parameters like tobacco abuse (p = 0.669), diabetes (p = 0.568) or surgical parameters (mesh size, defect region, flap design) did not influence the exposure rate. Surgical splints were not evaluated to reduce the exposure rate (p = 0.239). Gender (female) was significantly associated with less exposure rate (78,4% female vs. 21.6% male, p = 0.043). CONCLUSIONS: The results of this study suggest that the new digital protocol including patient-specific titanium meshes, resorbable membranes and bone grafting materials was proven to be a promising technique. To improve soft tissue healing, especially A®-PRF should be recommended.

Pedicle frozen autograft-prosthesis composite reconstructions for malignant bone tumors of the proximal femur.

BACKGROUND: Limb salvage surgery is becoming increasingly popular after tumor resection in the lower extremity. Biological reconstruction and use of megaprosthesis are main methods for malignant bone tumors of the proximal femur, which remain controversial due to short- and long-term complication in the proximal femur. Tumor-bearing bone treated by liquid nitrogen is one of biological reconstruction. This study aimed to evaluate the mid- and long-term functional outcomes and complications in patients treated with frozen autograft-prosthesis composite (FAPC) reconstructions in the proximal femur. METHODS: This retrospective study included 19 patients (10 women, 9 men) with malignant tumors of the proximal femur who underwent tumor-wide resection and FAPC reconstruction (mean age, 46 years; range, 9-77 years). The mean follow-up period of 69 months (range, 9-179 months). Functional outcomes, oncological outcome and complications were evaluated by Musculoskeletal Tumor Society score, clinical and radiological examinations. RESULTS: The overall survival rate was 68.4%, and the mean Musculoskeletal Tumor Society functional score was 26.4 points (88%). FAPC survival rates were 100 and 50% at 5 and 10 years, respectively. Five of the 19 patients (26%) had complications: 2 required prosthesis removal and 2 developed a deep infection around acetabular. Wear of the acetabulum occurred in 2 cases, while disease recurrence was occurred in 1 case. There were no cases of greater trochanter avulsion, obvious absorption around frozen bone, prosthesis loosening or leg length discrepancy. CONCLUSIONS: Due to without femoral osteotomy, this technique features satisfactory functional outcome and provide biomechanical stability that is comparable to those of other methods of biological reconstruction or megaprosthesis.

Nanocomposite Gel as Injectable Therapeutic Scaffold: Microstructural Aspects and Bioactive Properties.

The development of tissue scaffolds able to provide proper and accelerated regeneration of tissue is a main task of tissue engineering. We developed a nanocomposite gel that may be used as an injectable therapeutic scaffold. The nanocomposite gel is based on biocompatible gelling agents with embedded nanoparticles (iron oxide, silver, and hydroxyapatite) providing therapeutic properties. We have investigated the microstructure of the nanocomposite gel exposed to different substrates (porous materials and biological tissue). Here we show that the nanocomposite gel has the ability to self-reassemble mimicking the substrate morphology: exposition on porous mineral substrate caused reassembling of nanocomposite gel into 10× smaller scale structure; exposition to a section of humerus cortical bone decreased the microstructure scale more than twice (to ≤3 µm). The reassembling happens through a transitional layer which exists near the phase separation boundary. Our results impact the knowledge of gels explaining their abundance in biological organisms from the microstructural point of view. The results of our biological experiments showed that the nanocomposite gel may find diverse applications in the biomedical field.

Finite element analysis of an intramedulary anatomical strut for proximal humeral fractures with disrupted medial column instability: A cohort study.

BACKGROUND: Lateral locking plate (LLP) fixation has gained popularity for the treatment of proximal humeral fractures (PHFs); however, complications can occur due to loss of the medial cortical buttress from fracture comminution. MATERIALS AND METHODS: We designed a novel intramedullary anatomical medial strut with allograft bone (IAMSAB) using MIMICS software to specifically fill the intramedullary canal of the proximal humeral bone. We used finite element analysis to evaluate the biomechanical characteristics of a LLP, LLP-intramedullary fixation system (IFS), LLP-anatomical medial locking plate (AMLP), or the combined application of a LLP and IAMSAB (LLP-IAMSAB) fixation construct in patients with a PHF and an unstable medial column. RESULTS: For axial or rotational loads, under (normal) Nor or osteoporotic (Ost) bone conditions, the LLP-IAMSAB fixation construct was significantly stiffer than the LLP-IFS fixation construct, and displacement at the fracture site after LLP-IAMSAB fixation was significantly less than after LLP or LLP-IFS fixation (P < 0.05). Stiffness of the LLP-IAMSAB and LLP-AMLP fixation constructs and displacement at the fracture site after LLP-IAMSAB and LLP-AMLP fixation were not significantly different. The IFS, AMLP, and IAMSAB shared the load in the LLP and decreased the risk of implant failure. There were no significant differences in von Mises stress and stress distribution after fixation with the LLP-IFS, LLP-AMLP, and LLP-IAMSAB constructs. CONCLUSION: These data suggest that the IAMSAB can provide direct medial support or resistance to rotation and augment the biomechanics of the LLP. The combined application of the IAMSAB and LLP may achieve functional outcomes that are similar to the LLP-AMLP fixation construct.

A simple, effective, universal, and reusable osteotomy tool for jaw reconstructions with microvascular fibula transplants.

BACKGROUND: Precise, expensive individual saw guides are used with increasing frequency for the reconstruction of mandibular defects with fibular grafts. In this report, an alternative is presented - the Multiuse Cutting Jig (MUC-Jig, proprietary development). It is reusable, suitable for all patients, requires simple planning based on conventional CT imaging, and is more economical. METHODS: To investigate its precision, we conducted a nonblinded experimental study, with ten participating craniomaxillofacial surgeons. Osteotomies of four different fibula segments were carried out at the same angulation, with groups defined according to the proximal and distal fixed angulation: 45°, 30°, 15°, or 0°. The sagittal cut was performed proximally, with the coronal cut performed distally. The resulting 40 segments (n = 40) were analyzed with their Tx length (primary endpoint) and osteotomy angles, and compared to the original planning. RESULTS: The mean (SD) relative deviation of all grafts from the original planning was -0.08 mm (1.12) in length and -0.71° (3.15) for the angle. Only 45° (-2.04 ±â€¯3.71°) and 30° (-1.07 ±â€¯2.52°) cuts differed significantly (p < 0.05) from smaller angle grafts. The mean (SD) absolute deviation was 0.81 mm (0.27) in length and 2.13° (0.93) in graft angles. For individual transplants, 45° cuts (1.28 ±â€¯1.03 mm) differed significantly (p < 0.005) from others. We observed no differences in relative length or absolute angle deviation. CONCLUSIONS: The MUC-Jig is precise and cost-effective for osteotomies with medium angles and smooth reconstructions of template-guided procedures.

Injertos óseos en el fisurado labio-alvéolo-palatino (FLAP): casos clínicos / Bone grafts in the cleft lip and palate (CLP) patient: clinical cases

Objetivo: mostrar el tratamiento que realizamos en comunicaciones a nivel del reborde alveolar en los FLAP, tanto para pacientes con fisura unilateral como bilateral, realizados con cresta ilíaca tomada del paciente y basados en nuestra experiencia de más de 40 años. Casos clínicos: nuestro protocolo está dentro de lo que es el tratamiento que proponemos para FLAP, ortopédico y quirúrgico, teniendo en cuenta el crecimiento y desarrollo del maxilar superior, realizando dentro de éste lo que son las periostioplastías y los injertos óseos, con el correspondiente seguimiento de pacientes en el tiempo. Conclusión: se realiza un protocolo adecuado para cada paciente, para realizar el cierre de la comunicación bucosinusal, teniendo siempre en cuenta el crecimiento y desarrollo de cada paciente y no un tiempo fijo en general para todos ellos. Nos diferenciamos de otras personas que lo hacen en forma sistemática en tiempos quirúrgicos preestablecidos, igual para todos los pacientes (AU)