In vitro and in vivo dissolution of biocompatible S59 glass scaffolds.

Fabrication of porous tissue-engineering scaffolds from bioactive glasses (BAG) is complicated by the tendency of BAG compositions to crystallize in thermal treatments during scaffold manufacture. Here, experimental biocompatible glass S59 (SiO2 59.7 wt%, Na2O 25.5 wt%, CaO 11.0 wt%, P2O5 2.5 wt%, B2O3 1.3 wt%), known to be resistant to crystallization, was used in sintering of glass granules (300-500 µm) into porous scaffolds. The dissolution behavior of the scaffolds was then studied in vivo in rabbit femurs and under continuous flow conditions in vitro (14 days in vitro/56 days in vivo). The scaffolds were osteoconductive in vivo, as bone could grow into the scaffold structure. Still, the scaffolds could not induce sufficiently rapid bone ingrowth to replace the strength lost due to dissolution. The scaffolds lost their structure and strength as the scaffold necks dissolved. In vitro, S59 dissolved congruently throughout the 14-day experiments, resulting in only a slight reaction layer formation. Manufacturing BAG scaffolds from S59 that retain their amorphous structure was thus possible. The relatively rapid and stable dissolution of the scaffold implies that the glass S59 may have the potential to be used in composite implants providing initial strength and stable, predictable release of ions over longer exposure times.

Detecting Distal Radius Fractures Using a Segmentation-Based Deep Learning Model.

Deep learning algorithms can be used to classify medical images. In distal radius fracture treatment, fracture detection and radiographic assessment of fracture displacement are critical steps. The aim of this study was to use pixel-level annotations of fractures to develop a deep learning model for precise distal radius fracture detection. We randomly divided 3785 consecutive emergency wrist radiograph examinations from six hospitals to a training set (3399 examinations) and test set (386 examinations). The training set was used to develop the deep learning model and the test set to assess its validity. The consensus of three hand surgeons was used as the gold standard for the test set. The area under the ROC curve was 0.97 (CI 0.95-0.98) and 0.95 (CI 0.92-0.98) for examinations without a cast. Fractures were identified with higher accuracy in the postero-anterior radiographs than in the lateral radiographs. Our deep learning model performed well in our multi-hospital and multi-radiograph system manufacturer settings. Thus, segmentation-based deep learning models may provide additional benefit. Further research is needed with algorithm comparison and external validation.

Computer-aided 3D analysis of anatomy and radiographic parameters of the distal radius.

INTRODUCTION: This study applied mathematical modeling to examine the anatomy of the distal radius; to define the radiographic parameters in a 3D imaging modality; and to report their normal ranges in the uninjured radius. MATERIALS AND METHODS: A series of 50 cone-beam computed tomography (CBCT) scans of uninjured radii were analyzed using computer-aided image processing. The radius shape model was used to determine the optimal location for measuring the longitudinal axis. With the axis determined, the volar tilt and radial inclination angles and the areas of the articular facets and their reference points were analyzed. RESULTS: The optimal location for determining the longitudinal axis was between 28.8 and 53.3 mm proximally from the articular surface. The mean radial inclination angle was 21.8°. The mean volar tilt angle via the most distal tips of the volar and dorsal rims was 13.0°; along the lunate and scaphoid facets it was 9.1° and 11.2°, respectively. The scaphoid facet was larger than the lunate facet and 25% of it was convex. CONCLUSIONS: Computer-aided CBCT image processing offers an advanced tool to record 3D geometry and the radiographic parameters of the osseous structures of the wrist. Analysis of the distal radius' anatomy showed that the longitudinal axis was affected by its measurement location and subsequently also affected the determination of the angular parameters. We also report the variation of the volar tilt along the articular surface and the shapes and sizes of the articular facets.

Antibacterial Bioactive Glass, S53P4, for Chronic Bone Infections - A Multinational Study.

Osteomyelitis is an infectious process in bone that occasionally leads to bone destruction. Traditionally, the surgical treatment procedure is performed in combination with systemic and local antibiotics as a two-stage procedure that uses autograft or allograft bone for filling of the cavitary defect. Bioactive glass (BAG-S53P4) is a bone substitute with proven antibacterial and bone bonding properties.One hundred and sixteen patients who had verified chronic osteomyelitis was treated using BAG-S53P4 as part of the treatment. Most of the patients had previously undergone numerous procedures, sometimes for decades. A register of patient data obtained from 11 centers from Finland, Italy, the Netherlands, Germany, Azerbaijan and Poland was set-up and continuously maintained at Helsinki University Central Hospital.The location of the osteomyelitis was mainly in the tibia followed by the femur and then the calcaneus. The median age of the patients was 48 years (15-87). The patients were either treated according to a one-stage procedure without local antibiotics (85 %) or by a two-stage procedure using antibiotic beads in the first procedure (15 %). The minimum follow-up was 1 year (12-95 months, median 31).The cure rate was 104/116, the total success rate 90 % and most of the patients showed a rapid recovery.The study shows that (BAG-S53P4) can be used in a one-stage procedure in treatment of osteomyelitis with excellent results.

Direct ink writing of biocompatible chitosan/non-isocyanate polyurethane/cellulose nanofiber hydrogels for wound-healing applications.

The demand for new biocompatible and 3D printable materials for biomedical applications is on the rise. Ideally, such materials should exhibit either biodegradability or recyclability, possess antibacterial properties, and demonstrate remarkable biocompatibility with no cytotoxic effects. In this research, we synthesized biocompatible and 3D printable hydrogels tailored for biomedical applications, such as wound healing films, by combining antibacterial double-quaternized chitosan (DQC) with cystamine-based non-isocyanate polyurethane (NIPU-Cys) - a material renowned for enhancing both the flexibility and mechanical properties of the hydrogels. To improve the rheological behavior, swelling attributes, and printability, cellulose nanofibrils were introduced into the matrix. We investigated the impact of DQC on degradability, swelling capacity, rheological behavior, printability, and cell biocompatibility. The slightly cytotoxic nature associated with quaternary chitosan was evaluated, and the optimal concentration of DQC in the hydrogel was determined to ensure biocompatibility. The resulting hydrogels were found to be suitable materials for 3D printing via a direct ink writing technique (DIW), producing porous, biocompatible hydrogels endowed with valuable attributes suitable for various wound-healing applications.

CT arthrography of the wrist using a novel, mobile, dedicated extremity cone-beam CT (CBCT).

PURPOSE: To evaluate the feasibility and intra- and interobserver agreement of CBCT arthrography of wrist ligaments, triangular fibrocartilaginous complex (TFCC), and to assess the sensitivity (SE), specificity (SP), accuracy (ACC), and positive and negative predictive value (PPV, NPV) of CBCT arthrography in the diagnosis of scapholunate (SLL) and lunotriquetral (LTL) ligament tears, TFCC, and cartilage abnormalities of the scaphoid and lunate with their corresponding radial surfaces (scaphoid and lunate fossa) using a novel, mobile, dedicated extremity CBCT scanner. MATERIALS AND METHODS: Fifty-two consecutively enrolled subjects (26 M, 26 F, mean age 38 years, range 18-66 years) with suspected wrist ligament tears underwent CBCT-arthrography before normally scheduled MR arthrography.An extremity CBCT was used for imaging with isotropic voxel size of 0.4 × 0.4 × 0.4 mm(3). Subsequent routine 1.5 T MRI was performed using a dedicated wrist coil.Two observers reviewed the anonymized CBCT images twice for contrast enhancement (CE) and technical details (TD), for tears of the SLL, LTL, and TFCC. Also, cartilage abnormalities of the scaphoid and lunate with their corresponding radial surfaces (scaphoid and lunate fossa) were evaluated. Inter- and intraobserver agreement was determined using weighted kappa statistics. Since no surgery was performed, MRI served as a reference standard, and SE and SP, ACC, PPV, and NPV were calculated. RESULTS: Intra- and interobserver kappa values for both readers (reader 1/reader 2; first reading/second reading) with 95 % confidence limits were: CE 0.54 (0.08-1.00)/ 0.75 (0.46-1.00); 0.73 (0.29-1.00)/ 0.45 (0.07-0.83), TD 0.53 (0.30-0.88)/ 0.86 (0.60-1.00); 0.56 (0.22-0.91)/ 0.67 (0.37-0.98), SLL 0.59 (0.25-0.93)/ 0.66 (0.42-0.91); 0.31 (0.06-0.56)/ 0.49 (0.26-0.73), LTL 0.83 (0.66-1.00)/ 0.68 (0.46-0.91); 0.90 (0.79-1.00)/ 0.48 (0.22-0.74); TFCC (0.72-1.00)/ (0.79-1.00); 0.65 (0.43-0.87)/ 0.59 (0.35-0.83), radius (scaphoid fossa) 0.45 (0.12-0.77)/ 0.64 (0.31-0.96); 0.58 (0.19-0.96)/ 0.38 (0.09-0.66), scaphoid 0.43 (0.12-0.74)/ 0.76 (0.55-0.96); 0.37 (0.00-0.75)/ 0.32 (0.04-0.59), radius (lunate fossa) 0.68 (0.36-1.00)/ 0.42 (0.00-0.86); 0.62 (0.29-0.96)/ 0.51 (0.12-0.91), and lunate 0.53 (0.16-0.90)/ 0.68 (0.44-0.91); 0.59 (0.29-0.88)/ 0.42 (0.00-0.84), respectively. The overall mean accuracy was 82-92 % and specificity was 81-94 %. Sensitivity for LTL and TFCC tears was 76-83, but for SLL tears it was 58 %. For cartilage abnormalities, the accuracy and negative predictive value were high, 90-98 %. CONCLUSIONS: A dedicated CBCT extremity scanner is a new method for evaluating the wrist ligaments and radiocarpal cartilage. The method has an overall accuracy of 82-86 % and specificity 81-91 %. For cartilage abnormalities, the accuracy and negative predictive value were high.

Evaluation of bone growth around bioactive glass S53P4 by scanning acoustic microscopy co-registered with optical interferometry and elemental analysis.

Bioactive glass (BAG) is a bone substitute that can be used in orthopaedic surgery. Following implantation, the BAG is expected to be replaced by bone via bone growth and gradual degradation of the BAG. However, the hydroxyapatite mineral forming on BAG resembles bone mineral, not providing sufficient contrast to distinguish the two in X-ray images. In this study, we co-registered coded-excitation scanning acoustic microscopy (CESAM), scanning white light interferometry (SWLI), and scanning electron microscopy with elemental analysis (Energy Dispersive X-ray Spectroscopy) (SEM-EDX) to investigate the bone growth and BAG reactions on a micron scale in a rabbit bone ex vivo. The acoustic impedance map recorded by the CESAM provides high elasticity-associated contrast to study materials and their combinations, while simultaneously producing a topography map of the sample. The acoustic impedance map correlated with the elemental analysis from SEM-EDX. SWLI also produces a topography map, but with higher resolution than CESAM. The two topography maps (CESAM and SWLI) were in good agreement. Furthermore, using information from both maps simultaneously produced by the CESAM (acoustic impedance and topography) allowed determining regions-of-interest related to bone formation around the BAG with greater ease than from either map alone. CESAM is therefore a promising tool for evaluating the degradation of bone substitutes and the bone healing process ex vivo.

Pre- and post-operative diffusion tensor imaging of the median nerve in carpal tunnel syndrome.

OBJECTIVES: To use pre- and post-operative diffusion tensor imaging (DTI) to monitor median nerve integrity in patients suffering from carpal tunnel syndrome (CTS). METHODS: Diffusivity and anisotropy images along the median nerve were compared among 12 patients, 12 age-matched and 12 young control subjects and correlated with electrophysiological neurography results. Slice-wise DTI parameter values were calculated to focus on local changes. RESULTS: Results of pre-operative patients and age-matched control subjects differed only in the distal nerve. Moreover, pre-operative patients differed significantly from young controls and post-operative patients. The main abnormalities were increased diffusivity and decreased anisotropy in the carpal tunnel and distal median nerve. Post-operative clinical improvement was reflected in diffusivity, but not in anisotropy. Slice-wise analysis showed high pre-operative diffusivity at the distal nerve. All groups had relatively large inter-subject variation in both diffusivity and anisotropy. CONCLUSIONS: DTI can provide information complementary to clinical examination, electrophysiological recordings and anatomical MRI of diseases and injuries of peripheral nerves. However, similar age-related changes in diffusivity and anisotropy may weaken DTI specificity. Slice-wise analysis is necessary for detection of local changes in nerve integrity. KEY POINTS: • Diffusion tensor magnetic resonance imaging provides information complementary to conventional diagnostic methods. • Age caused similar changes to diffusivity and anisotropy as carpal tunnel syndrome. • Post-operative clinical improvement was reflected in diffusivity, but not in anisotropy. • Inter-subject variation in diffusivity and anisotropy was considerable.

The clinical significance of magnetic resonance imaging of the hand: an analysis of 318 hand and wrist images referred by hand surgeons.

Magnetic resonance imaging (MRI) is a common diagnostic tool in hand surgery. However, there is limited knowledge on the kind of findings that are relevant in treatment planning. We analysed the findings and utility of arm, wrist, metacarpal, and finger MRIs taken in a tertiary hand surgery clinic of 318 consecutive images from 316 patients referred by a hand surgeon or hand surgeon resident. Ganglions (28%), findings on the extensor carpi ulnaris tendon (18%) and on the triangular fibrocartilage (18%) were the most common findings and increased with patient age; the clinical significance of these findings was minimal. The correlation between the clinical scaphoid shift test or the fovea sign test and MRI was also non-significant. Despite findings on MRI, the diagnosis remained unsolved in 76 (24%) cases. However, MRI had a role in reassuring the patient, and in 70% of the cases, further follow-up was unnecessary. This study demonstrates that the indications for wrist and hand MRI must be considered thoroughly and interpretation of the MRI report requires knowledge.

Ultrasonography for the diagnosis of carpal tunnel syndrome: correlation of clinical symptoms, cross-sectional areas and electroneuromyography.

This study evaluates the usefulness of ultrasonography in diagnosing carpal tunnel syndrome (CTS). The cross-sectional area of the median nerve was measured at the forearm and its entry into the carpal tunnel and compared with clinical symptoms and electroneuromyography. A total of 124 patients were examined, 77 patients with clinically confirmed CTS and 47 controls. A significant correlation was found between the ultrasonography cross-sectional area values at entry points into the carpal tunnel and electroneuromyography. The highest sensitivity (87%) and specificity (91%) for different cut-off values (8.5-12.5 mm2) of the cross-sectional area was for 11.5 mm2. The use of ultrasonography may provide a quick and reliable differential diagnostic tool for the primary diagnosis of CTS in patients with classical symptoms.Level of evidence: II.

Enchondromas of the Hand: Curettage With Autogenous Bone vs. Bioactive Glass S53P4 for Void Augmentation.

Background/Aim Enchondroma is the most common primary bone tumour of the hand. When surgery is indicated, curettage with or without void augmentation has been described. However, only few comparative studies exist. The aim of this study was to compare the outcomes of hand enchondromas treated with autologous bone graft (AG) and bioactive glass S53P4 (BAG). PATIENTS AND METHODS: A retrospective comparative analysis was conducted among patients surgically treated for hand enchondromas at a tertiary referral centre during a 17-year period. RESULTS: A total of 190 patients (116 AG vs. 74 BAG) with 205 enchondromas were included. No statistically significant differences in outcome measures were observed. A reoperation was performed in five patients in the autologous bone-graft group; one patient presented a rare malignant transformation from enchondroma to chondrosarcoma after the primary operation. No reoperations were performed in the BAG group. CONCLUSION: Although AG is the gold standard for filling bony cavities, bone-graft retrieval can cause complications and postoperative pain. Our results suggest that S53P4 BAG is a safe and effective bone-graft material alternative for filling of enchondroma-evacuated cavities.

Scandinavian Surgical Society: The Oldest International Surgical Society in the World.

Scandinavian Surgical Society (SSS), Nordisk Kirurgisk Förening, founded in 1893, is the oldest international surgical society in the world. The purpose of the society is to promote scientific and clinical work as well as education in the field of surgery in the Nordic countries; Denmark, Finland, Sweden, Norway and Iceland. Nordic co-operation has long traditions in the medical field. The surgical development through the surgical communities and the long-term co-operation between the Nordic surgeons have affected the patient care and development of surgery throughout the Nordic region. An overview and a historical glance of the surgical communities in the Nordic countries from the 18th century are described as well as activities in the SSS from the beginning of 1893 to these days.

Instrumented spondylodesis in degenerative spondylolisthesis with bioactive glass and autologous bone: a prospective 11-year follow-up.

A prospective long-term follow-up study of bioactive glass (BAG)-S53P4 and autogenous bone (AB) used as bone graft substitutes for posterolateral spondylodesis in treatment of degenerative spondylolisthesis during 1996 to 1998 was conducted. The surgical procedure was a standardized instrumented posterolateral fusion that used USS/VAS. BAG was implanted on the left side of the fusion bed and AB on the right side. The operative outcome was evaluated on x-rays and computed tomography scans, and a clinical examination was also performed. Seventeen patients (12 women, 5 men) participated in the 11-year follow-up. The mean Oswestry Disability Index score at the follow-up was 21 (range 0 to 52), compared with 49 (range 32 to 64) at the preoperative time. A solid bony fusion was seen on computed tomography scans on the AB side in all patients and on the BAG side in 12 patients. The fusion rate of all fusion sites (n=41) for BAG as a bone substitute was 88% at the L4/5 level and 88% at the L5/S1 level. The use of BAG as a bone graft extender can be considered as a good alternative in spinal surgery in the future.

Congenital upper limb deficiencies and associated malformations in Finland: a population-based study.

PURPOSE: To calculate the national incidence of upper limb deficiencies and associated infant mortality in children in Finland using the International Federation of Societies for Surgery of the Hand (IFSSH) classification. Radial ray deficiency, ulnar ray deficiency, central ray deficiency, transverse arrest, phocomelia, undergrowth, and constriction band syndrome with skeletal defects were evaluated. METHODS: We reviewed upper limb deficiencies among all 753,342 births in Finland during 1993 to 2005 reported to the Finnish Register of Congenital Malformations. Classification of these upper limb deficiencies was done according to a modified IFSSH system. We calculated incidence, gender and side distributions, frequency of associated anomalies, and infant mortality rates in different subtypes of the deficiencies. Familial occurrence of congenital upper limb defects was recorded. RESULTS: A total of 419 cases (234 male, 185 female) of upper limb deficiencies were identified. The national incidence of upper limb deficiencies was 5.56 per 10,000 births and 5.25 per 10,000 live births. The most common upper limb abnormality was radial ray deficiency (138), followed by subgroups of undergrowth (91), upper limb defects due to constriction band syndrome (51), central ray deficiency (41), and ulnar ray deficiency (33). Perinatal mortality was 14%. Infant mortality among children with upper limb deficiencies was 137 per 1,000 live births, compared with an overall infant mortality of 3.7 per 1,000 live births in Finland. Additional birth defects were found in 60% of these children. Prevalence of upper limb defects in relatives of the census population was 2% (11 of 419). CONCLUSIONS: The national incidence of upper limb deficiencies is 5.25 per 10,000 live births. Congenital upper limb deficiencies are associated with additional birth defects in two thirds of cases. These children, especially children with radial ray deficiency, have a high perinatal mortality rate. When divided into subgroups using IFSSH classification, differences emerge in both associated anomalies and mortality.

Bioactive glass S53P4 and autograft bone in treatment of depressed tibial plateau fractures - a prospective randomized 11-year follow-up.

The clinical and radiological outcomes of bioactive glass (BAG)-S53P4 and autograft bone (AB) used as bone-graft substitutes in depressed tibial plateau fractures were evaluated in a prospective randomized 11-year follow-up study. All patients (n = 29) had sustained tibial plateau fractures with a joint-line depression of >3 mm. Fifteen patients (5 patients the BAG group, 10 patients in the AB group) participated in this long-term follow-up. X-rays were taken preoperatively, postoperatively, and at the long-term follow-up, and computed tomography (CT) scans were made at the long-term follow-up for evaluation of the bone substitute, osteoarthritis, the tibial-femoral angle, and deviation of mechanical axes. No material-dependent adverse effects were seen in any patient. The means of the articular surface depression on X-rays at the long-term follow-up were 1.4 mm (range: 0-2 mm) in the BAG group and 1.4 mm (range: 0-4 mm) in the AB group, and on CT scans the means were 2.2 mm (range: 2-3 mm), and 2.1 mm (range: 0-3), respectively. No significant difference in the tibial-femoral angle or deviation of mechanical axes was observed between the two groups. BAG-S53P4 can be used as a bone substitute in depressed lateral tibial plateau fractures with good functional and radiological long-term results.

Radiographic measurements of the normal distal radius: reliability of computer-aided CT versus physicians' radiograph interpretation.

We examined the reliability of a computer-aided cone-beam CT analysis of radiographic parameters of 50 normal distal radii and compared it with interobserver agreement of measurements made by three groups of physicians on two-dimensional plain radiographs. The intra-rater reliability of the computer-aided analysis was evaluated on 33 wrists imaged twice by cone-beam CT. The longitudinal axis, anterior tilt, radial inclination and ulnar variance were measured. The reliability of computer-aided analysis was excellent (intraclass correlation coefficient (ICC) 0.94-0.96) while the interobserver agreement of two-dimensional radiograph interpretation was good (ulnar variance, ICC 0.80-0.84) to poor (anterior tilt and radial inclination, ICC 0.20-0.42). We conclude that computer-aided cone-beam CT analysis was a reliable tool for radiographic parameter determination, whereas physicians demonstrated substantial variability especially in interpreting the angular parameters.

Usability issues in the operating room - Towards contextual design guidelines for medical device design.

Most usability assessments of medical devices describe the problems of individual devices in detail, but few account for the real context of use or provide designers with actionable guidelines for improvement. To fill this gap, this paper reports the results of a case study on the usability of operating room technologies and documents the creation of contextual design guidelines for operating room device design. We spent 64 h in a gynecological operating unit conducting interviews with staff and observing device use during surgery. With qualitative analysis methods and based on existing usability principles, we created 21 design guidelines for the operating room context. The new guidelines highlight interactions between multiple devices, staff members, as well as other contextual factors. While the guidelines require further validation, they can potentially support the creation of more safe, ergonomic, and intuitive medical devices.

Dissolution of Amorphous S53P4 Glass Scaffolds in Dynamic In Vitro Conditions.

The silicate-based bioactive glass S53P4 is clinically used in bone regenerative applications in granule form. However, utilization of the glass in scaffold form has been limited by the high tendency of the glass to crystallize during sintering. Here, careful optimization of sintering parameters enabled the manufacture of porous amorphous S53P4 scaffolds with a strength high enough for surgical procedures in bone applications (5 MPa). Sintering was conducted in a laboratory furnace for times ranging from 25 to 300 min at 630 °C, i.e., narrowly below the commencement of the crystallization. The phase composition of the scaffolds was verified with XRD, and the ion release was tested in vitro and compared with granules in continuous flow of Tris buffer and simulated body fluid (SBF). The amorphous, porous S53P4 scaffolds present the possibility of using the glass composition in a wider range of applications.

Bone morphogenic protein expression and bone formation are induced by bioactive glass S53P4 scaffolds in vivo.

The two-stage induced-membrane (IM) technique is increasingly used for treatment of large bone defects. In stage one, the bone defect is filled with polymethylmethacrylate (PMMA), which induces a membrane around the implant. In stage two, PMMA is replaced with bone graft. Bioactive glasses (BAGs) are bone substitutes with bone-stimulating and angiogenic properties. We have previously shown that a certain type of BAG can also induce a foreign-body membrane similar to PMMA. The aim of this study was to evaluate the bone-forming capacity of sintered BAG-S53P4 and poly(lactide-co-glycolide) (PLGA)-coated BAG-S53P4 scaffolds for potential use as bone substitutes in a single-stage IM technique. Sintered porous rods of BAG-S53P4, BAG-S53P4-PLGA, or PMMA were implanted in rabbit femurs for 2, 4, or 8 weeks. The expression of bone morphogenic protein (BMP)-2, -4, and -7 in the IMs of implanted materials were analyzed with real-time quantitative polymerase chain reaction. Micro-computed tomography imaging was used to evaluate bone growth and further verified with scanning electron microscopy. BAG-S53P4 and BAG-S53P4-PGLA scaffold IMs show similar or superior expression of BMP-2, -4, and -7 compared with PMMA IM. Bone ingrowth into BAG scaffolds increased over time. Active bone formation occurred inside the BAG scaffolds and the respective BMP expressions were similar or superior for the BAG IMs compared with PMMA, thus making BAGs a promising device for single-stage treatment of bone defects. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res B Part B: Appl Biomater, 2018. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 847-857, 2019.