Objective To study the effect of atlantoaxial pedicle and lateral mass screw in treat-ment of atlantoaxial instability. Methods A retrospective analysis was done on 11 eases of aflantoaxi-al instability treated with atlantoaxial pedicle and lateralmass screw from June 2006 to December 2007. Results The postoperative radiographs verified good position of all screws, with satisfactory atlantoaxial reduction. Follow-up for 3-21 months (average 12 months) showed no spinal cord and vertebral artery in-jury or interfixation failure. Conclusion Atlantoaxial pediele and lateral mass screw technique is a convenient method with solid fixation for treatment of atlantoaxial instability.

BACKGROUND: Ilioinguinal approach and modified Stoppa approach are commonly used to treat pelvic and acetabular fractures, but which one is safer and more effective remains controversial, so a meta-analysis is necessary.OBJECTIVE: To compare the efficacy of modified Stoppa approach and ilioinguinal approach for pelvic and/or acetabular fractures.METHODS: A computer-based retrieval of Cochrane library, PubMed, Embase, OVID, CNKI, WanFang, CBM and VIP databases was performed for the randomized controlled trials concerning modified Stoppa approach and ilioinguinal approach for pelvic and/or acetabular fractures published before October 2016. Meta-analysis was performed on RevMan5.3 software.RESULTS AND CONCLUSION: (1) Finally 11 randomized controlled trials were enrolled, including 722 patients. (2) Meta-analysis showed that the operation time, intraoperative blood loss, length of incision, volume of drainage and hospitalization time in the modified Stoppa approach group were significantly less than those in the ilioinguinal approach group (P < 0.05), and the clinical efficacy in the modified Stoppa approach group was significantly superior to that in the ilioinguinal approach group (P < 0.05). But there were no significant differences in Matta scores and postoperative complications between two groups (P > 0.05). (3) To conclude, modified Stoppa approach is safer and more effective for pelvic and/or acetabular fractures.

Objective To investigate the in vitro cytocompatibility of three-dimensional porous scaffolds of poly-D,L-lactic acid (PDLLA) and discuss the feasibility of PDLLA as a scaffold for bone tissue engineering.Methods BMSCs of the third passage were seeded on osteogenetic differentiation medium or culture medium containing 20％ volume fraction degraded liquid (PDLLA degradation liquid of 0,3,6,9,and 12 weeks) according to the random number table.Osteogenetic differentiation medium or culture medium without PDLLA was used as controls.Cell viability,cytotoxicity,and osteogenic differentiation were detected for study on cytocompatibility of PDLLA.Scanning electron microscopy was used to observe the growth of BMSCs on the surface of PDLLA scaffolds.Results PDLLA scaffolds presented no significant cytotoxic on the growth of BMSCs.PDLLA scaffolds had no negative effect on cell viability compared with the controls (t3 =-0.441,P =0.671; t6 =1.596,P =0.154; t9 =-0.492,P =0.636; t12 =-1.135,P=0.283).ALP staining and calcium nodule staining were positive and there were no significant differences in ALP and collagen Ⅰ protein quantitative detection compared with the controls.BMSCs grew well on the inner surface of the PDLLA three-dimensional porous scaffolds.Conclusion Three-dimensional porous scaffolds of PDLLA present good cytocompatibility in vitro and can be used as bone tissue engineering scaffolds for subsequent in vivo research.

BACKGROUND:After spinal cord injury, endogenous neural stem cel s are activated to proliferate and migrate to repair damaged tissue. As a clinical medicine, methylprednisolone shows a lot of functions, but its effects on endogenous neural stem cel s are stil unknown.
OBJECTIVE:To explore the effects of methylprednisolone on the proliferation and migration of endogenous neural stem cel s after spinal cord injury.
METHODS:Seventy-five Sprague-Dawley rats were used to make animal models of T10 complete paraplegia using Al en’s method, and randomized into methylprednisolone, normal saline and model groups. Rats in these three groups were given intraperitoneal injection of 1 g/L methylprednisolone solution at a dose of 30 mg/kg for 10 minutes and at a dose of 5.4 mg/kg/h for 23 hours, given intraperitoneal injection of normal saline at the same dose and given no treatment, respectively. Neurological and motor functions were assessed by somatosensory evoked potential and Basso Beattie Bresnahan scores at 7, 14, 21, 28 days after spinal cord injury. BrdU and Nestin staining of the injured spinal cord segment was conducted.
RESULTS AND CONCLUSION:A large amount of BrdU-and Nestin-positive cel s were visible in al the groups, and the number of these cel s reached the peach at 14 days after spinal cord injury. Methylprednisolone was found to inhibit BrdU-, Nestin-or double-positive cel s, indicating methylprednisolone can inhibit the proliferation and migration of endogenous neural stem cel s. The results of Basso Beattie Bresnahan scores showed no notable improvement in the motor function of the limbs. Methylprednisolone also showed no significant effects on the motor evoked potential latency, but promoted nerve conduction recovery. Al these findings indicate that methylprednisolone has some hindering effects on spinal cord repair by inhibiting the proliferation and migration of endogenous neural stem cel s after spinal cord injury.

BACKGROUND:A large number of biomechanical studies and clinical application research showed that unilateral pedicle screw fixation with a single cage can not only make the spine to obtain immediate stability, and also reduces the fixed segment stiffness. However, there is not related research on the change of adjacent segment disc nucleus pulposus volume with unilateral pedicle screw. OBJECTIVE:To evaluate the effects of unilateral pedicle screw fixation with a single cage on adjacent segment degeneration for treating lumbar degenerative disease with MRI measurement of lumbar nucleus pulposus volume. METHODS:A total of 34 patients with lumbar disc herniation were treated by posterior lumbar interbody fusion with unilateral pedicle screw fixation with a single cage insertion. There were L4-5 segment in 16 patients (9 males and 7 females) and L5-S1segment in 18 patients (10 males and 8 females). The fixator was taken out at 18 months after surgery. They were folowed up for 24 to 36 months. With MRI, the transverse diameter and sagittal diameter of the nucleus pulposus were measured by using T2-weighted images at 6, 12, 18, 30 months after treatment, while the nucleus pulposus height was measured by middle sagittal position. Cephalic intervertebral height was measured with angular bisector method on X-ray films. Effects of unilateral pedicle screw fixation on cephalic intervertebral disc degeneration were evaluated according to nucleus pulposus volume and the intervertebral space height. RESULTS AND CONCLUSION:(1) Nucleus pulposus volume at cephalic L3-4 on the fixed L4-5segment was reduced in male patients after 30 months of treatment compared with pre-treatment (P=0.139), but increased in female patients (P=0.143). (2) Nucleus pulposus volume at L4-5 near to fixed L5-S1 segment was slightly reduced in male patients after 30 months of treatment (P=0.096); nucleus pulposus volume was slightly increased in female patients after 6, 12, 18 and 30 months of treatment (P > 0.05). (3) Disc space height at cephalic L3-4 near to L4-5 segment was diminished in male and female patients at 30 months of treatment (P > 0.05). (4) Disc space height at cephalic L4-5 near to L5-S1 segment was slightly reduced in male and female patients compared with pre-treatment (P > 0.05). (5) Unilateral pedicle screw with a single cage could effectively prevent adjacent segment degeneration in treatment of partial lumbar intervertebral degenerative disease.

Objective To explore changes in coagulation function,assessed by thromboelastography (TEG) combined with D-dimer (D-D),in patients undergoing percutaneous vertebroplasty(PVP)or percutaneous kyphoplasty(PKP).Methods A total of 52 elderly patients with osteoporosis-associated vertebral compression fractures admitted into our hospital from May 2016 to November were enrolled in this study,including 13 men aged 64-91 years,with a mean age of(74.3 ± 10.5) years,and 39 women aged 60-89 years,with a mean age of(71.4 ± 7.3) years.Patients received vertebroplasty under local anesthesia,with 29 patients undergoing PVP and 23 cases taking PKP.Thromboelastography(TEG)and D-dimer(D-D)levels were measured at 1 h before,0.5 h,1 h and 3 h after bone cement injections,in order to analyze changes in patients' coagulation function.Results Compared with the coagulation parameters in patients 1 h before bone cement injections,the values of R,K,Angle,Ma,CI,EPL,LY30 and D-D had no significant difference in patients 0.5 h after bone cement injections (P ＞ 0.05);the values of R,Angle,CI,EPL and LY30 were significantly different(P ＜0.05),but the values of K,Ma and D-D had no significant difference(P ＞0.05)in patients 1 h after bone cement injections;the values of R,K,Angle,Ma,CI,LY30 and D-D had no significant difference(P＞0.05),but the value of EPL was significantly different in patients 3 h after bone cement injections(P ＜0.05).Conclusions The blood is in a transient hypercoagulable state during the time of 0.5 h to 3 h after PVP or PKP,which reaches the peak at the time of 1 h after operation,thereby increasing the risk of thrombosis.Therefore,some interventions such as anticoagulants could be carried out during the preoperative and postoperative period.Changes in coagulation function should be closely monitored after operation.Patients should start postoperative exercise early.

Objective To compare the clinical outcomes of transforaminal lumbar interbody fusion (TLIF) through Wiltse approach and posterior midline approach in the treatment of degenerative lumbar spondylolisthesis.Methods A total of 37 patients with degenerative lumbar spondylolisthesis were treated between March 2008 and March 2010,including 23 patients managed by TLIF via posterior midline approach ( posterior midline approach group) and 14 by TLIF via Wiltse approach ( Wiltse approach group).The Japanese Orthopaedic Association (JOA) score and visual ltanalogue scale (VAS) before and after operation,and the interbody fusion condition in both the Wiltse approach group and posterior midline approach group were reviewed and the clinical outcomes of both groups were compared.Results The follow-up lasted for 6-26 months ( mean,15.7 months),during which both groups had obvious relief in clinical symptoms like pain of waist and legs.X-ray photographs showed good spondylolisthesis reduction and interbody fusion,with no loosening or breakage of the internal fixators.The fusion rate of Wiltse approach group and posterior midline approach group at the last follow-up were 86％ and 87％,respectively.The operation time of Wiltse approach group and posterior midline approach group was ( 117.8 +25.6) minutes and ( 128.5 ± 38.7 ) minutes respectively ( P ＞ 0.05 ).The intra-operative blood loss of Wiltse approach group and posterior midline approach group was (203.5 ± 16.4) ml and (284.4 ±27.6) ml respectively (P ＜0.05).Both groups presented significant decrease of JOA score post-opera-tively (P ＜ 0.05).Also,the two groups sbowed significant difference concerning the VAS score in low back pain one week post-operatively (P ＜ 0.05),but no significant difference in terms of VAS score in leg pain at one week after operation (P＜0.05) and VAS score in pain of low back and legs at the final follow-up ( P ＞0.05).Conclusions In the management of lumbar spondylolisthesis,TLIF via Wiltse approach and via posterior midline approach can both achieve satisfactory interbody fusion rate and clinical outcomes,but the Wiltse approach results in relatively less intra-operative blood loss and faster postoperative recovery.