Objective To compare the growth and extracellular matrix biosynthesis of nucleus pulposus cells (NPCs)and bone marrow mesenchymal stem cells (BMSCs) in thermo-sensitive chitosan hydrogel and to choose seed cells for injectable tissue engineered nucleus pulposus. Methods NPCs were isolated and cultured from 3-week-old New Zealand rabbits (male or female, weighing 150-200 g). BMSCs were isolated and cultured from bone marrow of 1-month-old New Zealand rabbits (male or female, weighing 1.0-1.5 kg). The thermo-sensitive chitosan hydrogel scaffold was made of chitosan, disodium β glycerophosphate, and hydroxyethyl cellulose. Then, NPCs at the 2nd passage or BMSCs at the 3rd passage were mixed with chitosan hydrogel to prepare NPCs or BMSCs-chitosan hydrogel complex as injectable tissue engineered nucleus pulposus. The viabil ities of NPCs and BMSCs in the chitosan hydrogel were observed 2 days after compound culture. The shapes and distributions of NPCs and BMSCs on the scaffold were observed by scanning electron microscope (SEM) 1 week after compound culture. The histology and immunohistochemistry examination were performed. The expressions of aggrecan and collagen type II mRNA were analyzed by RT-PCR 3 weeks after compound culture. Results The thermo-sensitive chitosan hydrogel was l iquid at room temperature and sol idified into gel at37 (after 15 minutes) due to crossl inking reaction. Acridine orange/propidium iodide staining showed that the viabil ity rates of NPCs and BMSCs in chitosan hydrogel were above 90%. The SEM observation demonstrated that the NPCs and BMSCs distributed in the reticulate scaffold, with extracellular matrix on their surfaces. The results of HE, safranin O histology and immunohistochemistry staining confirmed that the NPCs and BMSCs in chitosan hydrogel were capable of producing extracellular matrix. RT-PCR results showed that the expressions of collagen type II and aggrecan mRNA were 0.564 ± 0.071 and 0.725 ± 0.046 in NPCs culture with chitosan hydrogel, and 0.713 ± 0.058 and 0.852 ± 0.076 in BMSCs culture with chitosan hydrogel; showing significant difference (P lt; 0.05). Conclusion The thermo-sensitive chitosan hydrogel has good cellular compatibil ity. BMSCs culture with chitosan hydrogel maintains better cell shape, prol iferation, and extracellular matrix biosynthesis than NPCs.
Objective To explore the feasibil ity and efficacy of percutaneous kyphoplasty (PKP) for the treatment of severe osteoporotic vertebral compression fracture (OVCF), and to assess the cl inical result of the PKP technique. Methods From May 2006 to October 2007, 12 patients with severe OVCF affecting more than 2/3 of the original vertebral body height were treated by using domestic PKP and percutaneous vertebroplasty (PVP) tool systems. There were 3 malesand 9 females, with the age of 56-82 years and a mean disease course of 4.2 months (1-49 months). Eleven thoracic vertebra and 4 lumbar vertebra suffered from severe vertebral compression fractures, which included 3 extremely severe thoracic OVCF. Four thoracic vertebra and 3 lumbar vertebra had not severe OVCF. There were 4 cases of single vertebral compression fracture, 6 cases of double fractures, and 2 cases of triple fractures. Only single side PKP and PVP were performed via extrapedicular approach in thoracic vertebra, and via transpedicular approach in lumbar spine under fluoroscopic control. Eight patients with severe thoracic compression fractures and 4 with severe lumbar fractures were treated by PKP. Four patients with relatively mild thoracic compression fractures and 3 with lumbar fractures were treated by PVP. Results The operation was successfully, 3 patients with extremely severe thoracic compression fractures received no intervention. The maximum expansion pressure of balloon was (1 068 ± 298) kPa, and the volume was (3.1 ± 1.2) mL during operation. The average operative time of PKP was (44.9 ± 10.6) minutes per vertebra, while the average operative time of PVP was (36.5 ± 6.8) minutes per vertebra. The average volume of injected bone cement was (2.5 ± 0.6) mL per thoracic vertebra, and (3.6 ± 1.2) mL per lumbar vertebra. The mean hospitalization time were (3.7 ± 1.6) days. Twelve cases were followed up 5-18 months (mean 8.6 months). The visual analogue scale scoreswere (2.35 ± 0.61) points 2 days after operation and (2.89 ± 1.07) points at last follow-up, there were statistically significant differences when compared with before operation (8.27 ± 1.36) points (P lt; 0.01). Extravertebral leakage of the bone cement into the paravertebral tissue and/or disc occurred in 6 patients (9 vertebra) without significant symptom. Conclusion One side approach PKP is a safe and effective technique for treatment of severe OVCF with markedly rel ief of pain.
Objective To investigate the feasibil ity of using thermo-sensitive chitosan hydrogen as a scaffold to construct tissue engineered injectable nucleus pulposus (NP). Methods Three-month-old neonatal New Zealand rabbits (male or female) weighing 150-200 g were selected to isolate and culture NP cells. The thermo-sensitive chitosan hydrogel scaffold wasmade of chitosan, disodium β-glycerophosphate and hydroxyethyl cellulose. Its physical properties and gross condition were observed. The tissue engineered NP was constructed by compounding the scaffold and rabbit NP cells. Then, the viabil ity of NP cells in the chitosan hydrogel was observed 2 days after compound culture and the growth condition of NP cells on the scaffold was observed by SEM 7 days after compound culture. NP cells went through histology and immunohistochemistry detection and their secretion of aggrecan and expression of Col II mRNA were analyzed by RT-PCR 21 days after compound culture. Results The thermo-sensitive chitosan hydrogel was l iquid at room temperature and sol idified into gel at 37 (15 minutes) due to crossl inking reaction. Acridine orange-propidiumiodide staining showed that the viabil ity rate of NP cells in chitosan hydrogel was above 90%. Scanning electron microscope observation demonstrated that the NP cells were distributed in the reticulate scaffold, with ECM on their surfaces. The results of HE, toluidine blue, safranin O and histology and immunohistochemistry staining confirmed that the NP cells in chitosan hydrogel were capable of producing ECM. RT-PCR results showed that the secretion of Col II and aggrecan mRNA in NP cells cultured three-dimensionally by chitosan hydrogen scaffold were 0.631 ± 0.064 and 0.832 ± 0.052, respectively,showing more strengths of producing matrix than that of monolayer culture (0.528 ± 0.039, 0.773 ± 0.046) with a significant difference (P lt; 0.05). Conclusion With good cellular compatibilities, the thermo-sensitive chitosan hydrogel makes it possible for NP cells to maintain their normal morphology and secretion after compound culture, and may be a potential NP cells carrier for tissue engineered NP.
ObjectiveTo investigate the clinical results and complication prevention of minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) in the treatment of single-segment severe lumbar spinal stenosis (LSS).MethodsThe clinical data of 112 patients with severe LSS treated with MIS-TLIF between January 2010 and January 2017 were retrospectively analyzed. There were 43 males and 69 females, aged 52-81 years, with an average age of 65.3 years. The disease duration ranged from 4 to 126 months, with an average of 10.5 months. Clinical manifestations: 104 cases of low back pain, 91 cases of nervous intermittent claudication of both lower limbs, 21 cases of unilateral nerve root pain and/or numbness, and 5 cases of cauda equina nerve injury. The 112 cases were all severe central spinal stenosis, including 32 cases with lateral recess stenosis, 20 cases with foramen stenosis, 9 cases with ossification of ligamentum flavum, 38 cases with disc herniation; 14 cases with two complications and 5 cases with three. Stenosis segment: L3, 4 in 6 cases, L4, 5 in 89 cases, and L5, S1 in 17 cases. Surgical methods included bilateral decompression through bilateral approach (60 cases), bilateral decompression through unilateral approach (15 cases), and unilateral decompression (37 cases). The operation time, intraoperative blood loss, visual analogue scale (VAS) score of low back pain and leg pain, Oswestry disability index (ODI) score, fusion rate, and surgical complications were recorded. At last follow-up, the lumbar fusion was evaluated by Bridwell method, grades Ⅰ and Ⅱ were expressed as fusion.ResultsThe operation time was 83-186 minutes (mean, 126.8 minutes), and the intraoperative blood loss was 65-630 mL (mean, 163.1 mL). All the 112 patients were followed up 25-49 months, with an average of 35.1 months. The VAS score of low back pain and leg pain and ODI score at each time point after operation were significantly improved when compared with preoperative scores (P<0.05). There was no significant difference between the VAS score of low back pain and leg pain and ODI score at the other time points except 1 month after operation (P<0.05). At last follow-up, 2 cases of cauda equina nerve injury recovered and 3 cases partially recovered. According to Bridwell classification criteria, 58 cases were grade Ⅰ, 47 cases were grade Ⅱ, and 7 cases were grade Ⅲ. The fusion rate was 93.8%. Perioperative complications included 5 cases of incision complications (superficial infection in 3 cases, hematoma formation in 2 cases), 19 cases of internal fixator complications (intraoperative end plate fracture in 8 cases, fusion cage sinking in 11 cases at last follow-up), and 15 cases of neurological complications (dural sac tear in 10 cases, transient neurological symptoms of lower extremities aggravated in 5 cases). Conclusion MIS-TLIF treatment of single-level severe LSS can achieve good clinical results, while there is a risk of serious complications. Full understanding of the clinical and imaging features of the disease and reasonable and careful operation are helpful to control the occurrence of cauda equina nerve damage.