A 3D-printed bioactive polycaprolactone scaffold assembled with core/shell microspheres as a sustained BMP2-releasing system for bone repair.

Integration of biological factors and hierarchical rigid scaffolds is of great interest in bone tissue engineering for fabrication of biomimetic constructs with high physical and biological performance for enhanced bone repair. Core/shell microspheres (CSMs) delivering bone morphogenetic protein-2 (BMP-2) and a strategy to integrate CSMs with 3D-printed scaffolds were developed herein to form a hybrid 3D system for bone repair. The scaffold was printed with polycaprolactone (PCL) and then coated with polydopamine. Shells of CSMs were electrosprayed with alginate. Cores were heparin-coated polylactic acid (PLA) microparticles fabricated via simple emulsion and heparin coating strategy. Assembly of microspheres and scaffolds was realized via a self-locking method with the assistance of controlled expansion of CSMs. The hybrid system was evaluated in the rat critical-sized bone defect model. CSMs released BMP-2 in a tunable manner and boosted osteogenic performance in vitro. CSMs were then successfully integrated inside the scaffolds. The assembled system effectively promoted osteogenesis in vitro and in vivo. These observations show the importance of how BMP-2 is delivered, and the core/shell microspheres represent effective BMP-2 carriers that could be integrated into scaffolds, together forming a hybrid system as a promising candidate for enhanced bone regeneration.

Biomechanical Evaluation and Preliminary Clinical Results of Anterolateral Screw Fixation for Oblique Lumbar Interbody Fusion Surgery.

BACKGROUND: The most common complication of oblique lumbar interbody fusion (OLIF) is endplate fracture/subsidence. The aim of this study was to evaluate biomechanical stability in patients undergoing OLIF surgery with anterolateral screw fixation (ASF). METHODS: Based on a previously validated model technique, L4-L5 functional surgical models corresponding to the ASF and bilateral pedicle screw fixation (BPSF) methods were created. Finite element models were developed to compare the biomechanics of the ASF and BPSF groups. We retrospectively analyzed 18 patients with lumbar degenerative diseases who underwent OLIF with ASF in Shenzhen Hospital of Southern Medical University from April 2020 to April 2021. Intraoperative and postoperative complications were observed. RESULTS: Compared with the BPSF model, the maximum stresses of the L4 inferior endplate and L5 superior endplate were greatly increased in the ASF model. The contact surface between the vertebrae and screw (CSVS) in the ASF model produced nearly 100% more stress than the BPSF model at all moments. In clinical practice, after a 12-month follow-up, 7 adverse events were observed, including 3 cases of left thigh pain/numbness, 3 cases of cage subsidence, and 1 case of screw loosening. CONCLUSIONS: OLIF surgery with ASF could not reduce the maximum stresses on the endplate and CSVS, which may be a potential risk factor for cage subsidence and screw loosening.

MicroRNA­186­5p downregulation inhibits osteoarthritis development by targeting MAPK1.

As a chronic degenerative joint disease, the characteristics of osteoarthritis (OA) are degeneration of articular cartilage, subchondral bone sclerosis and bone hyperplasia. It has been reported that microRNA (miR)­186­5p serves a key role in the development of various tumors, such as osteosarcoma, non­small­cell lung cancer cells, glioma and colorectal cancer. The present study aimed to investigate the effect of miR­186­5p in OA. Different concentrations of IL­1ß were used to treat the human chondrocyte cell line CHON­001 to simulate inflammation, and CHON­001 cell injury was assessed by detecting cell viability, apoptosis, caspase-3 activity and the levels of TNF­α, IL­8 and IL­6. Subsequently, reverse transcription­quantitative PCR was performed to measure miR­186­5p expression. The results demonstrated that following IL­1ß treatment, CHON­001 cell viability was suppressed, apoptosis was promoted, the caspase-3 activity was significantly enhanced and the release of TNF­α, IL­8 and IL­6 was increased. In addition, IL­1ß treatment significantly upregulated miR­186­5p expression in CHON­001 cells. It was also identified that MAPK1 was a target gene of miR­186­5p, and was negatively regulated by miR­186­5p. miR­186 inhibitor and MAPK1­small interfering RNA (siRNA) were transfected into CHON­001 cells to investigate the effect of miR­186­5p on CHON­001 cell injury induced by IL­1ß. The results demonstrated that miR­186 inhibitor suppressed the effects of IL­1ß on CHON­001 cells, and these effects were reversed by MAPK1­siRNA. In conclusion, the present results indicated that miR­186­5p could attenuate IL­1ß­induced chondrocyte inflammation damage by increasing MAPK1 expression, suggesting that miR­186­5p may be used as a potential therapeutic target for OA.

Biomechanical Comparison of Stand-Alone and Bilateral Pedicle Screw Fixation for Oblique Lumbar Interbody Fusion Surgery-A Finite Element Analysis.

BACKGROUND: The most common complication of oblique lumbar interbody fusion (OLIF) is endplate fracture/subsidence. The mechanics of endplate fracture in OLIF surgery are still unclear. The aim of the present study was to evaluate the biomechanical stability in patients undergoing OLIF surgery with stand-alone (SA) and bilateral pedicle screw fixation (BPSF) methods. METHODS: A finite element model of the L1-L5 spinal unit was established and validated. Using the validated model technique, L4-L5 functional surgical models corresponding to the SA and BPSF methods were created. Simulations using the models were performed to investigate OLIF surgery. A 500-N compression force was applied to the superior surface of the model to represent the upper body weight, and a 7.5-Nm moment was applied to simulate the 6 movement directions of the lumbar spinal model: flexion and extension, right and left lateral bending, and right and left axial rotation. Finite element models were developed to compare the biomechanics of the SA and BPSF groups. RESULTS: Compared with the range of motion of the intact lumbar model, that of the SA model was decreased by 79.6% in flexion, 54.5% in extension, 57.2% in lateral bending, and 50.0% in axial rotation. The BPSF model was decreased by 86.7% in flexion, 77.3% in extension, 76.2% in lateral bending, and 75.0% in axial rotation. Compared with the BPSF model, the maximum stresses of the L4 inferior endplate and L5 superior endplate were greatly increased in the SA model. The L4 inferior endplate stress was increased to 49.7 MPa in extension, and the L5 superior endplate stress was increased to 47.7 MPa in flexion, close to the yield stress of the lamellar bone (60 MPa). CONCLUSIONS: OLIF surgery with BPSF could reduce the maximum stresses on the endplate, which might reduce the incidence of cage subsidence. OLIF surgery with the SA method produced more stress compared with BPSF, especially in extension and flexion, which might be a potential risk factor for cage subsidence.

Comparison of the Effects of Epidural Anesthesia and Local Anesthesia in Lumbar Transforaminal Endoscopic Surgery.

BACKGROUND: Percutaneous endoscopic lumbar discectomy (PELD) is a standard technique for the treatment of lumbar disc hernia. Thus far, most surgeons have recommended local anesthesia. However, in clinical practice, some patients experience pain and are unable to cooperate with the surgery during intervertebral foramen hemp expansion. The use of general anesthesia may create a greater risk of complications because of nerve root anomalies; thus, intraoperative neurophysiological monitoring should be utilized. Reports regarding the use of epidural anesthesia are few in comparison. OBJECTIVE: To investigate the risks and contingency plans of epidural anesthesia in lumbar transforaminal endoscopic surgery. STUDY DESIGN: A retrospective analysis of all lumbar transforaminal endoscopic surgeries performed from 2010 to 2014. SETTING: Kanghua hospital. METHODS: Patients treated with local and epidural anesthesia were divided into 2 groups. In local anesthesia group (A) and local anesthesia group (B), 0.5% lidocaine and 0.25% ropivacaine was administered, respectively. The incidences of complications, including urological complications, in each surgical group as well as Oswestry disability idex (ODI) improvement rates, postoperative patient satisfaction rates, and x-ray exposure times were assessed.

BACKGROUND: There are many different reasons why patients could be experiencing pain in the gluteal area. Previous studies have shown an association between radicular low back pain (LBP) and gluteal pain (GP). Studies locating the specific level responsible for gluteal pain in lumbar disc hernias have rarely been reported. METHODS: All patients with lumbar disc herniation (LDH) in the Kanghua hospital from 2010 to 2014 were recruited. All patients underwent a lumbar spine MRI to clarify their LDH diagnosis, and patients were allocated to a GP group and a non-GP group. To determine the cause and effect relationship between LDH and GP, all of the patients were subjected to percutaneous endoscopic lumbar discectomy (PELD). RESULTS: A total of 286 cases were included according to the inclusive criteria, with 168 cases in the GP group and 118 cases in the non-GP group. Of these, in the GP group, 159 cases involved the L4/5 level and 9 cases involved the L5/S1 level, while in the non-GP group, 43 cases involved the L4/5 level and 48 cases involved the L5/S1 level. PELD was performed in both groups. Gluteal pain gradually disappeared after surgery in all of the patients. Gluteal pain recrudesced in a patient with recurrent disc herniation (L4/5). CONCLUSIONS: As a clinical finding, gluteal pain is related to low lumbar disc hernia. The L4/5 level is the main level responsible for gluteal pain in lumbar disc hernia. No patients with gluteal pain exhibited involvement at the L3/4 level.

OBJECTIVE: To analyze the effect of biomechanical reconstruction of the hip in metal-on-metal total hip resurfacing. METHODS: Thirty patients undergoing hip resurfacing arthroplasties were enrolled in this study. The clinical outcomes of the patients were assessed according to the Harris Hip Score before and after the surgery, X-ray examinations and biomechanical reconstruction evaluations. RESULTS: After the operation, the length of the patients' legs was shortened by a mean of 2.4 mm. and the femoral offset was decreased by a mean of 5.45 mm. No dislocation were be found in these patients. The preoperative Harris Hip Score was 36.69-/+7.16, significantly lower than that postoperative score (89.63-/+3.36, P<0.01). CONCLUSION: Precise biomechanical reconstruction of the hip can be achieved in hip resurfacing arthroplasty, and the stability and functional restoration is guaranteed by large diameter prosthesis design.

OBJECTIVE: To evaluate the short-term outcome of patients receiving metal-on-mental hip resurfacing arthroplasty and analyze the factors affecting the result. METHODS: In 13 patients receiving metal-on-metal hip resurfacing arthroplasties with scheduled follow-up, the treatment outcomes were assessed according to the Harris Hip Score. RESULTS AND CONCLUSION: The short-term outcomes of hip resurfacing arthroplasties were encouraging, and intraoperative complications, infections, peripheral nerve palsy, hip dislocations or clinically overt lower limb deep vein thrombosis occurred in none of these cases. All the patients reported complete or major pain relief. Clinical assessment according to the Harris Hip Score revealed an improvement from an average score of 36.69 preoperatively to 89.63 after the surgery. Crutch use lasted for a maximum of 4 weeks postoperatively in these patients, after which the patients were all capable of walking without crutches with full weight-bearing.

Synthetic burn dressing remains the central theme for burn dressing development. The advantages and disadvantages of current available dressings were reviewed. As one of the most successful dressings, the hydrogel burn dressing, its combination with other materials and related progress in researches were presented in detail. Finally, the trend in development of synthetic burn dressing was presented.

Which level is responsible for gluteal pain in lumbar disc hernia?

BACKGROUND: There are many different reasons why patients could be experiencing pain in the gluteal area. Previous studies have shown an association between radicular low back pain (LBP) and gluteal pain (GP). Studies locating the specific level responsible for gluteal pain in lumbar disc hernias have rarely been reported. METHODS: All patients with lumbar disc herniation (LDH) in the Kanghua hospital from 2010 to 2014 were recruited. All patients underwent a lumbar spine MRI to clarify their LDH diagnosis, and patients were allocated to a GP group and a non-GP group. To determine the cause and effect relationship between LDH and GP, all of the patients were subjected to percutaneous endoscopic lumbar discectomy (PELD). RESULTS: A total of 286 cases were included according to the inclusive criteria, with 168 cases in the GP group and 118 cases in the non-GP group. Of these, in the GP group, 159 cases involved the L4/5 level and 9 cases involved the L5/S1 level, while in the non-GP group, 43 cases involved the L4/5 level and 48 cases involved the L5/S1 level. PELD was performed in both groups. Gluteal pain gradually disappeared after surgery in all of the patients. Gluteal pain recrudesced in a patient with recurrent disc herniation (L4/5). CONCLUSIONS: As a clinical finding, gluteal pain is related to low lumbar disc hernia. The L4/5 level is the main level responsible for gluteal pain in lumbar disc hernia. No patients with gluteal pain exhibited involvement at the L3/4 level.

[Biomechanical reconstruction of the hip in metal-on-metal total hip resurfacing].

OBJECTIVE: To analyze the effect of biomechanical reconstruction of the hip in metal-on-metal total hip resurfacing. METHODS: Thirty patients undergoing hip resurfacing arthroplasties were enrolled in this study. The clinical outcomes of the patients were assessed according to the Harris Hip Score before and after the surgery, X-ray examinations and biomechanical reconstruction evaluations. RESULTS: After the operation, the length of the patients' legs was shortened by a mean of 2.4 mm. and the femoral offset was decreased by a mean of 5.45 mm. No dislocation were be found in these patients. The preoperative Harris Hip Score was 36.69-/+7.16, significantly lower than that postoperative score (89.63-/+3.36, P<0.01). CONCLUSION: Precise biomechanical reconstruction of the hip can be achieved in hip resurfacing arthroplasty, and the stability and functional restoration is guaranteed by large diameter prosthesis design.

[Short-term clinical follow-up of metal-on-metal hip resurfacing arthroplasty].

OBJECTIVE: To evaluate the short-term outcome of patients receiving metal-on-mental hip resurfacing arthroplasty and analyze the factors affecting the result. METHODS: In 13 patients receiving metal-on-metal hip resurfacing arthroplasties with scheduled follow-up, the treatment outcomes were assessed according to the Harris Hip Score. RESULTS AND CONCLUSION: The short-term outcomes of hip resurfacing arthroplasties were encouraging, and intraoperative complications, infections, peripheral nerve palsy, hip dislocations or clinically overt lower limb deep vein thrombosis occurred in none of these cases. All the patients reported complete or major pain relief. Clinical assessment according to the Harris Hip Score revealed an improvement from an average score of 36.69 preoperatively to 89.63 after the surgery. Crutch use lasted for a maximum of 4 weeks postoperatively in these patients, after which the patients were all capable of walking without crutches with full weight-bearing.

[Progress in the studies on hydrogel burn dressings].

Synthetic burn dressing remains the central theme for burn dressing development. The advantages and disadvantages of current available dressings were reviewed. As one of the most successful dressings, the hydrogel burn dressing, its combination with other materials and related progress in researches were presented in detail. Finally, the trend in development of synthetic burn dressing was presented.