Objective To investigate the effect of bisphosphonate medication (zoledronic acid,aclasta) on spinal fusion for osteoporotic patients through radiographic,clinical,and biological assessments.Methods A total of 79 patients with osteoporosis who were candidates for single-level posterior lumbar interbody fusion was randomly assigned to the experimental group (zoledronic acid injection,5mg,on the third day after surgery) or the control group (the same amount of saline injection,on the third day after surgery).Functional radiography and CT scans were used to evaluate fusion status.Bridging bone formation was graded into 3 categories:Grade A (bridging bone through bilateral vertebral),Grade B (bridging bone through a unilateral vertebral),or Grade C (incomplete bony bridging).The incidence of vertebral compression fractures occurring after surgery was assessed by means of MR imaging.A solid fusion was defined as less than 5° of angular motion in flexion-extension radiographs and the presence of Grade A or B bridging bone.Bone metabolic markers (β-C-terminal telopeptide of type Ⅰ collagen,β-CTX; and N-terminal propeptide of type Ⅰ collagen,PINP) were measured to investigate the biological effects of zoledronic acid on spinal fusion.Bone mineral density of femoral neck was measured by the dual X-ray absorptiometry.Clinical outcome was evaluated by means of the Oswestry Disability Index (ODI).Results Grade A or B bridging bone was more frequently observed in the experimental group at 3,6,and 9 months postoperatively (all P ＜ 0.05,respectively,Mann-Whitney U-test).At 12-months postoperative follow-up,bridging bone and solid fusion were not significantly different.No vertebral fractures were observed in the experimental group,whereas 6 patients in the control group showed vertebral compression fractures(P ＜ 0.05,Mann-Whitney U-test).Biochemical analysis of bone turnover demonstrated that zoledronic acid inhibited bone resorption from the early phase of the fusion process and also suppressed bone formation.Poor clinical results in the control group were demonstrated by ODI.Conclusions Osteoporosis patients undergoing spinal fusion who take bisphosphonates throughout the postoperative period was recommended.

BACKGROUND:Animal model of infection is established using bioluminescent gene-labeled bacteria, which stimulate local environment of spine infection and reveal the pathophysiological mechanism of spine infection.
OBJECTIVE:To evaluate the feasibility and safety of anterior one-stage debridement, autogenous iliac bone grafting and titanium plate internal fixation in the management of pyogenic spinal infections in spine.
METHODS:Total y 24 Chinese dogs were adopted in the study to develop a canine model of acute pyogenic spondylodiscitis using a bioluminescent strain of Staphylococcus aureus Xen29. The animal models were detected by X-radiography, CT and MRI examinations. After 4 weeks of modeling, al the animals underwent one-stage debridement, autogenous iliac bone grafting and anterior titanium plate internal fixation. Antibiotics contained Cefazolin and Gentamicin were administrated daily since perioperative period to 4 weeks after surgery. The titanium plate and adjacent vertebra were removed surgical y at various postoperative time points (4, 8, 12, 24 weeks) when the dogs were kil ed. The excised tissues and retrieved implants were cultured with conventional bacteria, bacteria 16S rRNA and specific Nuc gene of Staphylococcus aureus. PCR and bioluminescence imaging technique were used to detect the presence of bacteria.
RESULTS AND CONCLUSION:The surgical wound was healed uneventful y. Gross observation and MRI examination of the specimens showed that there was no abscess formation or signs of infection recurrence. The infection rate was 41.7%(10/24) and 75%(18/24) in the procedure of conventional bacteria and bacteria 16S rRNA cultivation. The results showed that the sensibility of PCR technique used to detect the presence of bacteria by amplifying the highly conservative gene sequence of 16S rRNA was significantly higher than that of conventional bacterial cultivation procedure (P<0.05). The PCR detection of specific Nuc gene of Staphylococcus aureus showed the existence of Staphylococcus aureus (1/24). However, Staphylococcus aureus Xen29 with genetic marker was not detected around the implant by bioluminescence imaging technique (0/24). Al of the results showed that bacterium adhering to prosthesis in vivo is an universal phenomenon. The bacteria identified from prosthesis which was taken during the surgery and the bacteria by which the spine was infected before the surgery was not homologous. The one-stage debridement, autogenous bone grafting and anterior titanium plate internal fixation is safe and effective in the management of pyogenic spinal infections. Using of internal fixator can not lead to recurrence or persistence of infection.

To evaluate the efficacy and safety of modified pedicle subtraction osteotomy for treatment of thoracolumbar old fracture with kyphosis.
 Methods: From January 2003 to January 2013, 58 patients of thoracolumbar kyphosis, who underwent modified pedicle subtraction osteotomy, were reviewed. Among them, 45 cases underwent initial operation and 13 cases underwent revision surgery. Preoperative and postoperative kyphotic Cobb's angle, score of back pain, as well as the incidence of complication were accessed by using visual analogue scale (VAS) and Oswestry disability index (ODI).
 Results: Mean follow-up duration was 42 months (range, 24-60 months). Average operative time was 258 min (range, 190-430 min), while average bleeding was 950 mL (range, 600-1 600 mL). All the patients were significantly improved in function and self-image, and achieved kyphosis correction with 17.9°± 4.3°. VAS of low back pain was decreased by 3.1±0.6; ODI was dropped by 25.3%±5.5%. 3 patients (5.2%) suffered anterior thigh numbness and got recovery after 3 months of follow-up. Complications happened in 19 patients, including 12 with cerebrospinal fluid leak, 4 with superficial wound infection, and 3 with urinary tract infection. All these complications were managed properly and none of them underwent reoperation.
 Conclusion: Modified pedicle subtraction osteotomy is a safe and effective technique for the treatment of old fracture with kyphosis.
Back Pain ; surgery ; Blood Loss, Surgical ; statistics & numerical data ; Cerebrospinal Fluid Leak ; epidemiology ; Female ; Follow-Up Studies ; Fractures, Bone ; complications ; surgery ; Humans ; Hypesthesia ; etiology ; Kyphosis ; etiology ; surgery ; Lumbar Vertebrae ; injuries ; surgery ; Male ; Operative Time ; Osteotomy ; adverse effects ; methods ; Postoperative Complications ; epidemiology ; Reoperation ; statistics & numerical data ; Retrospective Studies ; Surgical Wound Infection ; epidemiology ; Thoracic Vertebrae ; injuries ; surgery ; Treatment Outcome ; Urinary Tract Infections ; epidemiology