3D-printed antibiotic-loaded bone cement spacers as adjunctive therapy for hip periprosthetic infection after arthroplasty: A clinical assessment.

OBJECTIVE: To explore the effect of three-dimensional (3D) printing to create personalized antibiotic-loaded bone cement (ALBC) spacers to assist in treatment of periprosthetic infection after total hip arthroplasty (THA). METHODS: The data of 40 patients with postoperative infection after THA were analysed retrospectively. The patients were divided into two groups: the 3D-printing group (age 47-78 years, n = 20) and the conventional group (age 57-78 years, n = 20). In stage I surgery, 3D-printed silicone moulds were used to create ALBC spacers for the 3D-printing group, while traditional manual methods were used to create spacers for the conventional group. After the infection was controlled, both groups underwent conventional hip revision surgery (stage II surgery). All patients were evaluated using the Harris Hip Score (HHS) (primary outcome) for hip function. RESULTS: All 40 patients had follow-up data from 3 months after stage I surgery and 12 months after stage II surgery. The intergroup difference in HHS was 11.25 points [97.5% confidence interval (CI) 7.92-14.58; P < 0.01] at 3 months after stage I surgery, and 9.15 points (97.5% CI 4.82-13.48; P < 0.01) at 12 months after stage II surgery. The overall difference between the two groups was 9.55 points (97.5% CI 5.83-13.27; P < 0.01), which was significant (P < 0.05). CONCLUSION: During the follow-up period, the hip function of the 3D-printing group was superior to that of the conventional group following the treatment of infections after THA.

The occurrence mechanisms of extreme events in a class of nonlinear Duffing-type systems under random excitations.

The occurrence mechanisms of extreme events under random disturbances are relatively complex and not yet clear. In this paper, we take a class of generalized Duffing-type systems as an example to reveal three mechanisms for the occurrence of extreme events. First, it is intuitive that a very large excitation can generate extreme events, such as the Lévy noise. In such a case, extreme excitation works, while it does not require much about the systems. Second, when a system has a bifurcation structure, if the difference of the branches at the bifurcation point is large, a randomly varying bifurcation parameter can lead to extreme events. Finally, when a system has rare attractors, a random impulse excitation, such as Poisson white noise, is able to cause the system to escape from one general attractor into rare attractors. Such a kind of special regime switching behavior can lead to extreme events. These results reveal the possible mechanisms of extreme events in a class of nonlinear Duffing-type systems and provide guidance for further prediction and avoidance of extreme events.

Evaluation of outcomes of discectomy with a dynamic neutralization system in treatment of lumbar disk herniation / Evaluación de los resultados de la discectomía con un sistema de neutralización dinámica en el tratamiento de la hernia de disco lumbar

Objective The study aimed to explore the clinical outcomes of discectomy with dynamic neutralization system (Dynesys) for single-segmental lumbar disk herniation (LDH) versus simple discectomy. Methods The eligible patients with single-segmental LDH were randomly divided into the discectomy with Dynesys group (group A) and the simple discectomy group (group B). The Oswestry disability index (ODI), visual analog score (VAS), radiological results of intervertebral height and range of motion (ROM) of the treated segment were evaluated pre- and post-operatively in both groups. Operation duration and blood loss were recorded. Complications, reoperation, and mortality were also assessed. All patients received a 2-year follow-up. Results 123 (96.1%) participants completed the follow-up. The operation duration and blood loss of group B were significantly lower than those of group A (p<0.05). After operation, ODI and VAS were improved significantly in both groups, and there was no significant difference between the two groups immediately after surgery. But a rising trend was found in ODI and VAS of group B, especially after the 1-year follow-up (p<0.05). X-rays showed a continuing loss of intervertebral height of the treated segment in group B, while it was preserved in group A (p<0.05). ROM of the treated segment was also maintained stable in group A. Conclusion Discectomy with Dynesys is safe and effective for LDH treatment (AU)

Objetivo El objetivo de este estudio es explorar los resultados clínicos de la discectomía con sistema de neutralización dinámica (Dynesys) para la hernia de disco lumbar (LDH) de un solo segmento vs. la discectomía simple. Métodos Los pacientes elegibles con LDH de un solo segmento se dividieron aleatoriamente en el grupo de discectomía con Dynesys (grupo A) y el grupo de discectomía simple (grupo B). El índice de discapacidad de Oswestry (ODI), la puntuación analógica visual (VAS), los resultados radiológicos de la altura intervertebral y el rango de movimiento (ROM) del segmento tratado se evaluaron antes y después de la operación en ambos grupos. Se registraron la duración de la operación y la pérdida de sangre. También se evaluaron las complicaciones, la reintervención y la mortalidad. Todos los pacientes recibieron un seguimiento de dos años. Resultados Completaron el seguimiento 123 (96,1%) participantes. La duración de la operación y la pérdida de sangre del grupo B fueron significativamente menores que las del grupo A (p < 0,05). Después de la operación, ODI y VAS mejoraron significativamente en ambos grupos y no hubo diferencias significativas entre los dos grupos inmediatamente después de la cirugía. Pero se encontró una tendencia ascendente en ODI y EVA del grupo B, especialmente después del seguimiento de un año (p < 0,05). Las radiografías mostraron una pérdida continua de la altura intervertebral del segmento tratado en el grupo B, mientras que se conservó en el grupo A (p < 0,05). El ROM del segmento tratado también se mantuvo estable en el grupo A. Conclusión La discectomía con Dynesys es segura y efectiva para el tratamiento de LDH (AU)

Evaluation of outcomes of discectomy with a dynamic neutralization system in treatment of lumbar disk herniation.

OBJECTIVE: The study aimed to explore the clinical outcomes of discectomy with dynamic neutralization system (Dynesys) for single-segmental lumbar disk herniation (LDH) versus simple discectomy. METHODS: The eligible patients with single-segmental LDH were randomly divided into the discectomy with Dynesys group (group A) and the simple discectomy group (group B). The Oswestry disability index (ODI), visual analog score (VAS), radiological results of intervertebral height and range of motion (ROM) of the treated segment were evaluated pre- and post-operatively in both groups. Operation duration and blood loss were recorded. Complications, reoperation, and mortality were also assessed. All patients received a 2-year follow-up. RESULTS: 123 (96.1%) participants completed the follow-up. The operation duration and blood loss of group B were significantly lower than those of group A (p<0.05). After operation, ODI and VAS were improved significantly in both groups, and there was no significant difference between the two groups immediately after surgery. But a rising trend was found in ODI and VAS of group B, especially after the 1-year follow-up (p<0.05). X-rays showed a continuing loss of intervertebral height of the treated segment in group B, while it was preserved in group A (p<0.05). ROM of the treated segment was also maintained stable in group A. CONCLUSION: Discectomy with Dynesys is safe and effective for LDH treatment.

Three-dimensional-printed polycaprolactone scaffolds with interconnected hollow-pipe structures for enhanced bone regeneration.

Three-dimensional (3D)-printed scaffolds are widely used in tissue engineering to help regenerate critical-sized bone defects. However, conventional scaffolds possess relatively simple porous structures that limit the delivery of oxygen and nutrients to cells, leading to insufficient bone regeneration. Accordingly, in the present study, perfusable and permeable polycaprolactone scaffolds with highly interconnected hollow-pipe structures that mimic natural micro-vascular networks are prepared by an indirect one-pot 3D-printing method. In vitro experiments demonstrate that hollow-pipe-structured (HPS) scaffolds promote cell attachment, proliferation, osteogenesis and angiogenesis compared to the normal non-hollow-pipe-structured scaffolds. Furthermore, in vivo studies reveal that HPS scaffolds enhance bone regeneration and vascularization in rabbit bone defects, as observed at 8 and 12 weeks, respectively. Thus, the fabricated HPS scaffolds are promising candidates for the repair of critical-sized bone defects.

Three-Dimensional-Printed Guiding Template for Unicompartmental Knee Arthroplasty.

BACKGROUND: For unicompartmental knee arthroplasty (UKA), accurate alignment of the limb is crucial. This study is aimed at investigating the efficacy and safety of a three-dimensional printed patient-customized guiding template (3DGT) for UKA. METHODS: A total of 22 patients receiving UKA were randomly divided into the 3DGT-UKA group (n = 11) and traditional UKA group (T-UKA group; n = 11). In the 3DGT-UKA group, the line and angle of osteotomy were decided on a 3D image of the limb reconstructed from imaging data; a guiding template was then designed and printed out. The patients in the T-UKA group underwent conventional UKA. Prosthesis size, operation time, postoperative drainage, hip-knee angle (HKA), pain, and Hospital for Special Surgery (HSS) scores were recorded at day 1, week 1, month 1, and month 3 after surgery. RESULTS: There was no significant difference in the size of prostheses between the preoperatively designed and actually used in the 3DGT-UKA group (p > 0.05). HKA was comparable in 3DGT-UKA and T-UKA patients. Operation time was shorter (53.6 ± 6.4 minutes vs. 75.8 ± 7.1 minutes) and wound drainage was less (93.2 ± 3.9 mL vs. 85.2 ± 3.0 mL) in 3DGT-UKA than in T-UKA (p < 0.05). Hospital stay was shorter in the 3DGT-UKA group. The 3DGT-UKA group had a lower VAS score on day 1, week 1, and month 1 and a higher HSS score on week 1 and month 1 after surgery. No varus/valgus deformity or prosthesis loosening was observed in either group at the final follow-up. CONCLUSION: The 3D-printed patient-customized guiding template may help decrease operation time, decrease blood loss, and improve short-term clinical outcomes in patients undergoing UKA surgery.

A Clinical Application Study of Mixed Reality Technology Assisted Lumbar Pedicle Screws Implantation.

BACKGROUND This was a prospective comparative study of mixed reality (MR) technology assisted lumbar pedicle screws placement and traditional lumbar pedicle screws placement. MATERIAL AND METHODS Fifty cases of lumbar pedicle screws placement were randomly divided into 2 groups: 25 cases with MR technology in group A, and 25 cases without MR technology in group B. All patients had their scores on the Oswestry disability index (ODI) of low back pain and the visual analog scale (VAS) of the affected lower limb recorded at pre-operation. Blood loss, operative duration, success rate of first penetration by tap, and number of times C-arm fluoroscopy was performed were recorded at intraoperation. The postoperative drainage was recorded. The ODI of low back pain and VAS of the affected lower limb were recorded at 1, 3, and 6 months after operation. RESULTS Group A had less bleeding, shorter operation time, higher success rate of first penetration by tap, and fewer times using C-arm fluoroscopy at intraoperation (P<0.05). There was significant difference in ODI scores and VAS scores at 1 mouth after operation (P<0.05). The postoperative drainage of group A was less than group B (P<0.05). The implantation accuracy of group A was higher than group B (P<0.05). The postoperative recovery rate of low back pain of group A was faster than group B (P<0.05). CONCLUSIONS The safety of spinal surgery and implantation accuracy of pedicle screw fixation system could be increased by MR technology.

Percutaneous kyphoplasty assisted with/without mixed reality technology in treatment of OVCF with IVC: a prospective study.

BACKGROUND: The purpose of this study was to assess the clinical outcome of percutaneous kyphoplasty (PKP) assisted with mixed reality (MR) technology in treatment of osteoporotic vertebral compression fracture (OVCF) with intravertebral vacuum cleft (IVC). METHOD: Forty cases of OVCF with IVC undergoing PKP were randomized into a MR technology-assisted group (group A) and a traditional C-arm fluoroscopy group (group B). Both groups were performed PKP and evaluated by VAS scores, ODI scores, radiological evidence of vertebral body height, and kyphotic angle (KA) at pre-operation and post-operation. The volume of injected cement, fluoroscopy times, and operation time were recorded. And cases of non-PMMA-endplates-contact(NPEC) in radiological evidence was also recorded postoperatively. The clinical outcomes and complications were evaluated afterwards. All patients received 10 to 14 months follow-up, with an average of 12 months. RESULT: This MR-assisted group (group A) acquired more about the amount of the polymethyl methacrylate (PMMA) injection and postoperative vertebral height and less about postoperative KA, fluoroscopy times, and operation time compared with the control group (group B) (P < 0.05). The VAS scores and ODI scores in both groups have improved, but more significantly in group A (P < 0.05). Also, more cases achieve both-endplates-touching of cement in group A (P < 0.05). And there are less of the loss of vertebral height, KA, and occurrence of re-collapse of the vertebra in group A during the follow-up (P < 0.05). CONCLUSION: PKP assisted with MR technology can accurately orientate the position of IVC area, which can be augmented by the balloon leading to more satisfied vertebral height improvement, cement diffusion, and pain relief. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03959059 . Registered 25 September 2016.

Lithium Chloride-Releasing 3D Printed Scaffold for Enhanced Cartilage Regeneration.

BACKGROUND We synthetized a 3D printed poly-ε-caprolactone (PCL) scaffold with polydopamine (PDA) coating and lithium chloride (LiCl) deposition for cartilage tissue engineering and analyzed its effect on promoting rabbit bone marrow mesenchymal stem cells (rBMSC) chondrogenesis in vitro. MATERIAL AND METHODS PCL scaffolds were prepared by 3D printing with a well-designed CAD digital model, then modified by PDA coating to produce PCL-PDA scaffolds. Finally, LiCl was deposited on the PDA coating to produce PCL-PDA-Li scaffolds. The physicochemical properties, bioactivity, and biocompatibility of PCL-PDA-Li scaffolds were accessed by comparing them with PCL scaffolds and PCL-PDA scaffolds. RESULTS 3D PCL scaffolds exhibited excellent mechanical integrity as designed. PDA coating and LiCl deposition improved surface hydrophilicity without sacrificing mechanical strength. Li⁺ release was durable and ion concentration did not reach the cytotoxicity level. This in vitro study showed that, compared to PCL scaffolds, PCL-PDA and PCL-PDA-Li scaffolds significantly increased glycosaminoglycan (GAG) formation and chondrogenic marker gene expression, while PCL-PDA-Li scaffolds showed far higher rBMSC viability and chondrogenesis. CONCLUSIONS 3D printed PCL-PDA-Li scaffolds promoted chondrogenesis in vitro and may provide a good method for lithium administration and be a potential candidate for cartilage tissue engineering.

[Clinical study of three-dimensional printed navigation template assisted Ludloff osteotomy in treatment of moderate and severe hallux valgus].

Objective: To explore the effectiveness and advantage of three-dimensional (3D) printed navigation templates assisted Ludloff osteotomy in treatment of moderate and severe hallux valgus. Methods: Between April 2013 and February 2015, 28 patients (28 feet) with moderate and severe hallux valgus who underwent Ludloff osteotomy were randomly divided into 2 groups ( n=14). In group A, the patients were treated with Ludloff osteotomy assissted with a 3D printed navigation template. In group B, the patients were treated with traditional Ludloff osteotomy. There was no significant difference in gender, age, affected side, and clinical classification between 2 groups ( P>0.05). The operation time and intraoperative blood loss were recorded. The ankle function of the foot at preoperation, immediate after operation, and last follow-up were assessed by the American Orthopedic Foot and Ankle Society (AOFAS) score. Besides, the X-ray film were taken to assess the hallux valgus angle (HVA), intermetatarsal angle (IMA), and the first metatarsal length shortening. Results: All patients were followed up 18-40 months (mean, 26.4 months). The operation time and intraoperative blood loss in group A were significantly less than those in group B ( P<0.05). The HVA, IMA, and AOFAS scores in groups A and B at immediate after operaton and last follow-up were sinificantly improved when compared with preoperative values ( P<0.05); but no significant difference was found between at immediate after operation and at last follow-up ( P>0.05). No significant difference was found in HVA and IMA between group A and group B at difference time points ( P>0.05). There were significant differences in AOFAS score and the first metatarsal length shortening at immediate after operation and at last follow-up between 2 groups ( P<0.05). Except 1 case of metastatic metatarsalgia in group B, there was no other operative complications in both groups. Conclusion: 3D printed navigation template assisted Ludloff osteotomy can provide accurate preoperative planning and intraoperative osteotomy. It is an ideal method for moderate and severe hallux valgus.