Removal of collagen three-dimensional scaffold bubbles utilizing a vacuum suction technique.

The process of generating type I/II collagen scaffolds is fraught with bubble formation, which can interfere with the three-dimensional structure of the scaffold. Herein, we applied low-temperature vacuum freeze-drying to remove mixed air bubbles under negative pressure. Type I and II rubber sponges were acid-solubilized via acid lysis and enzymolysis. Thereafter, vacuum negative pressure was applied to remove bubbles, and the cover glass press method was applied to shape the type I/II original scaffold. Vacuum negative pressure was applied for a second time to remove any residual bubbles. Subsequent application of carbamide/N-hydroxysuccinimide cross-linked the scaffold. The traditional method was used as the control group. The structure and number of residual bubbles and pore sizes of the two scaffolds were compared. Based on the relationship between the pressure and the number of residual bubbles, a curve was created, and the time of ice formation was calculated. The bubble content of the experimental group was significantly lower than that of the control group (P < 0.05). The pore diameter of the type I/II collagen scaffold was higher in the experimental group than in the control group. The time of icing effect of type I and II collagen solution was 136.54 ± 5.26 and 144.40 ± 6.45 s, respectively. The experimental scaffold had a more regular structure with actively proliferating chondrocytes that possessed adherent pseudopodia. The findings indicated that the vacuum negative pressure method did not affect the physical or chemical properties of collagen, and these scaffolds exhibited good biocompatibility with chondrocytes.

Comparison of the Effectiveness of Simple Plate Fixation and Plate Combined with Local Fixation of Broken Ends in the Treatment of Oblique Fracture of Midshaft Clavicle.

OBJECTIVE: To compare the clinical efficacy of performing simple plate fixation with that using a plate combined with fracture end fixation to investigate the necessity of fracture end fixation outside the plate in cases of oblique fracture of the middle clavicle. METHODS: This was a retrospective follow-up study of patients with middle clavicle oblique fractures (Robinson types 2A1 and 2A2) between 2015 and 2020. Patients were divided into two groups according to their treatment options: the simple plate fixation (SPF) group (n = 79; 43 men and 36 women; average age, 46.37 ± 14.54 years) and the plate combined with fracture local fixation (PLFP) group (n = 81; 36 men and 45 women; average age, 48.42 ± 12.55 years). Intraoperative blood loss, operation time, postoperative fracture healing time, postoperative shoulder function score (Constant-Murley and disabilities of the arm, shoulder, and hand [DASH] scores), clinical complications, and postoperative subjective satisfaction were compared between the two groups. RESULTS: One hundred sixty patients with a sufficient follow-up period were included in the final analysis: 79 in the SPF group (follow-up time: 16.24 ± 3.94 months) and 81 in the PLFP group (follow-up time: 16.15 ± 3.43 months). Age, sex, body mass index, follow-up duration, fracture classification, and cause of injury were not significantly different between the two groups. There was no significant difference in blood loss, Constant-Murley and DASH scores, follow-up period, and postoperative subjective satisfaction between the two groups (P > 0.05). The fracture healing time was shorter in the PLFP group than in the SPF group (4.41 ± 0.99 vs. 4.87 ± 1.60 months, P < 0.05), but the operation duration was longer in the PLFP group than in the SPF group (65.48 ± 16.48 min, P < 0.05). There were seven (complication rate, 8.86%) and five (complication rate, 6.17%) cases that had complications in the SPF and PLFP groups, respectively. There was no significant difference in the complication rates between the two groups (P > 0.05). CONCLUSION: Although the healing time was shorter in the PLFP group than in the SPF group, the clinical efficiency of the two methods in the treatment of oblique fracture of the middle clavicle was similar.

Construction of tissue-engineered nucleus pulposus by stimulation with periodic mechanical stress and BMP-2.

Intervertebral disc (IVD) degeneration, which is common among elderly individuals, mainly manifests as low back pain and is caused by structural deterioration of the nucleus pulposus (NP) due to physiological mechanical stress. NP mesenchymal stem cells (NPMSCs) around the IVD endplate have multidirectional differentiation potential and can be used for tissue repair. To define favorable conditions for NPMSC proliferation and differentiation into chondroid cells for NP repair, the present study simulated periodic mechanical stress (PMS) of the NP under physiological conditions using MSC chondrogenic differentiation medium and recombinant human BMP-2 (rhBMP-2). rhBMP-2 effectively promoted NPMSC proliferation and differentiation. To clarify the mechanism of action of rhBMP-2, integrin alpha 1 (ITG A1) and BMP-2 were inhibited. PMS regulated the BMP-2/Smad1/RUNX2 pathway through ITG A1 and promoted NPMSC proliferation and differentiation. During tissue-engineered NP construction, PMS can effectively reduce osteogenic differentiation and promote extracellular matrix protein synthesis to enhance structural NP recovery.

Biomechanical Model Study of the Effect of Partial Facetectomy on Lumbar Stability Under Percutaneous Endoscopy.

OBJECTIVE: To investigate the effect of partial facetectomy on lumbar stability using percutaneous endoscopy. METHODS: Five male adult volunteers with no history of lumbar disease participated in the study. Based on computed tomography data, a three-dimensional model of the L3-S1 segment was created using the Mimics l5.0 and Ansys 13.0 software. The use of an 8.5-mm-diameter ring saw was simulated to cut through 5 different needle insertion points (IPs) commonly used in the clinic on the left-side facet joint (FJ) of L5 to perform facetectomy. The first to third IPs were on the apex of the superior FJ, the midpoint of the ventral side of the superior FJ, and the lowest point of the ventral side of the superior FJ. The fourth and fifth IPs represented the positions of the second and third IPs (8.5 mm/2) after the radius of the ring saw was translated to the dorsal side of the superior FJ. Physiologic load was applied to the human models. The pressure on the left and right FJ of the L5 vertebra, the pressure on the L4-5 intervertebral disc, and the range of motion of the lumbar spine were recorded when normal flexion and extension and lateral flexion and rotation of the lumbar spine model after facetectomy were simulated. RESULTS: Compared with the intact group, the second IP, maximum pressure on the L4-5 intervertebral disc after facetectomy was not significantly different under any condition (P > 0.05). The maximum pressure on the left FJ of L5 showed significant differences during right rotation of the lumbar spine (P < 0.05). The pressure on the right FJ of L5 was significantly different during left rotation of the lumbar spine (P < 0.05). The range of motion of the lumbar spine was not significantly different under any condition (P > 0.05). CONCLUSIONS: The second IP at the midpoint of the ventral side of the superior FJ showed minimal effect on lumbar spine biomechanics compared with all the other IPs during percutaneous transforaminal facetectomy. Thus, it can be considered as the most suitable IP for facetectomy.

The effect of different cross-linking conditions of EDC/NHS on type II collagen scaffolds: an in vitro evaluation.

The purpose of this paper is to analyze the properties of porcine cartilage type II collagen scaffolds crosslinked with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxy-succinamide (EDC/NHS) under different conditions. The porous EDC/NHS-crosslinked scaffolds were obtained through a two-step freeze-drying process. To determine the optimal crosslinking condition, we used different solvents and various crosslinking temperatures to prepare the scaffolds. Three crosslinking solutions were prepared with different solvents, photographs were taken with a flash in the darkroom, and light transmission was observed. Type II collagen was crosslinked on a horizontal shaker at a speed of 60 r/min according to the above grouping conditions, and then the structural change of the scaffold in each group was observed. To investigate the swelling ratio and the in vitro degradation of the collagen scaffold, tests were also carried out by immersion of the scaffolds in a PBS solution and digestion in type II collagenase, respectively. The influence of the scaffolds on the proliferation of chondrocytes was assessed by the methyl thiazolyl tetrazolium colorimetric assay. The morphology of the crosslinked scaffolds cocultured with chondrocytes was characterized by a scanning electron microscope. The results proved that 75% alcohol and a crosslinking temperature of 37 °C are recommended. Collagen fibrils are more densely packed after crosslinking with EDC/NHS and have a more uniform structure than that of noncrosslinked ones. The EDC-crosslinked scaffolds possessed excellent mechanical property and biocompatibility.

Application of lamina replantation with ARCH plate fixation in thoracic and lumbar intraspinal tumors.

The aim of the present study was to investigate the clinical effects of lamina replantation with ARCH plate fixation on patients with thoracic and lumbar intraspinal tumors, following laminectomy. Thirteen patients with thoracic and lumbar intraspinal tumors underwent total lamina replantation with ARCH plate fixation and repair of the supraspinous ligaments, following laminectomy and tumor enucleation. To investigate the clinical effect of lamina replantation with ARCH plate fixation, pre- and postoperative visual analog scale (VAS), and Oswestry Disability Index (ODI) scores were determined, and pre- and postoperative X-ray and magnetic resonance imaging (MRI) examinations were conducted. Computed tomography (CT) examinations were also included in the follow-up. No complications were observed pre- or postoperatively. The VAS and ODI results 2 weeks following surgery and at the final follow-up examination demonstrated a significant improvement compared with the corresponding preoperative results. The X-ray examination results indicated a satisfactory internal fixation location, without any characteristics of a fracture, lumbar scoliosis, kyphosis or instability. Following the surgery, the CT and MRI examination results demonstrated that healing of the lamina bone and repair of the supraspinous ligament had occurred without tumor recurrence or spinal epidural scar recompression. Two of the 13 cases were lost to follow-up. The results indicated that in patients with thoracic and lumbar intraspinal tumors, lamina replantation with ARCH plate fixation following total laminectomy is effective and provides thoracolumbar stability. Furthermore, this has been identified to be an effective technique for preventing intraspinal scar proliferation.

Effects of interspinous spacers on lumbar degenerative disease.

The present study aimed to evaluate the early effects of interspinous spacers on lumbar degenerative disease. The clinical outcomes of 23 patients with lumbar degenerative disease, treated using interspinous spacer implantation alone or combined with posterior lumbar fusion, were retrospectively studied and assessed with a visual analogue scale (VAS) and the Oswestry Disability Index (ODI). Pre-operative and post-operative interspinous distance, disc space height, foraminal width and height and segmental lordosis were determined. The early effects and complications associated with the interspinous spacers were recorded. The surgical procedures performed with the in-space treatment were easy and minimally invasive. The VAS scores and ODI were improved post-operatively compared with pre-operatively. Significant changes in the interspinous distance, disc space height, foraminal width and height and segmental lordosis were noted. In-space treatment for degenerative lumbar disease is easy and safe, with good early effects. The in-space system provides an alternative treatment for lumbar degenerative disease.

1858 C/T polymorphism of the protein tyrosine phosphatase nonreceptor 22 gene and rheumatoid arthritis risk in europeans: a meta-analysis.

BACKGROUND AND AIMS: A single nucleotide polymorphism (SNP) of the protein tyrosine phosphatase nonreceptor gene (PTPN22) confers susceptibility to rheumatoid arthritis (RA) and certain other classical autoimmune diseases. The association between PTPN22 1858C/T polymorphism and the risk of RA is still controversial and ambiguous; therefore, we performed this meta-analysis to confirm some relationships. METHODS: We conducted a search in the PubMed database without a language limitation, covering all papers published until June 20, 2011. Overall, 19 case-control studies with 11,727 cases and 12,640 controls were retrieved based on the search criteria for RA susceptibility related to the 1858C/T polymorphism. Odds ratios (OR) and 95% confidence intervals (CI) were used to assess the strength of this association. Publication bias was assessed with Eggers test. RESULTS: We found that PTPN22 1858C/T polymorphism could increase RA risk in overall genetic models in Europeans (T-allele vs. C-allele, OR = 1.54, 95% CI = 1.47-1.62, P(heterogeneity) = 0.143; TT vs. CC, OR = 2.86, 95% CI = 2.29-3.57, P(heterogeneity) = 0.302; TC vs. CC, OR = 1.45, 95% CI = 1.38-1.53, P(heterogeneity) = 0.273; TT + TC vs. CC, OR = 1.49, 95% CI = 1.42-1.56, P(heterogeneity) = 0.208; TT vs. TC + CC, OR = 2.52, 95% CI = 1.95-3.25, P(heterogeneity) = 0.296). Furthermore, significant relationships were detected among PTPN22 1858C/T polymorphism and RF(+) or RF(-) RA risk. No obvious evidence of publication bias was detected in the overall analysis. CONCLUSIONS: Our study indicated that PTPN22 1858T allele was significantly associated with increased RA risk.

[Pedicle screw fixation of thoracic spinal fracture assisted by CT-based navigation system].

OBJECTIVE: To evaluate the feasibility and accuracy of thoracic pedicle screw fixation when assisted by a CT-based navigation system. METHODS: A total of 102 thoracic pedicle screws inserted by a CT-based navigation system (n = 24) (Group A) and 98 thoracic pedicle screws inserted by X-ray fluoroscopy (n = 22) (Group B) were observed by postoperative CT scan. The accuracy of both series was compared. And the process of navigation was investigated. RESULTS: Among Group A, 99 were of grade I (97.1%), 3 grade II and 0 grade III; among Group B, 88 were of grade I (89.8%), 8 grade II and 2 grade III. One patient of grade III had the intractable pain of chest and back. Neural damage was not demonstrated. The difference was statistically significant (P < 0.05). CONCLUSION: A CT-based navigation system can increase accuracy of thoracic pedicle screw fixation.