An Approach to Primary Tumors of the Upper Cervical Spine With Spondylectomy Using a Combined Approach: Our Experience With 19 Cases.

STUDY DESIGN: A retrospective study. OBJECTIVE: To examine the link between major complications, surgical techniques, and perioperative care in the intralesional spondylectomy of the upper cervical spine. SUMMARY OF BACKGROUND DATA: Spondylectomy has been demonstrated to prolong cancer-free survival in many patients with locally aggressive spinal tumors. However, the challenging nature of this surgical procedure and the potential for severe complications often limit its application in the upper cervical spine. METHODS: Nineteen patients with primary upper cervical tumors were treated with spondylectomy from March 2005 to August 2009, using either the anterior-posterior or posterior-anterior approach. Anterior procedures were transmandibular, transoral, or high retropharyngeal. Anterior reconstructions were performed in plates with iliac crest strut grafts, plates with mesh cages, and Harms mesh cages alone. Occipitocervical fixation was performed with Halo-vest application for postoperative immobilization. RESULTS: Vertebral artery injuries occurred unilaterally in 5 cases intraoperatively: 4 occurred in the anterior approach of anterior-posterior procedures. Fusion was achieved in 9 patients with intact internal instrumentation. Fusion with the anterior construct in a tilted position occurred in 3 patients, all of whom underwent anterior-posterior procedures with Halo-vest immobilization for less than 1 month. Nonunion occurred in 3 cases after the posterior-anterior procedure because of anterior bone graft absorption. Prolonged Halo-vest immobilization maintained postoperative stability. Failure of internal instrumentation occurred in 3 cases. Anterior construct dislocation and severe tilting occurred in 2 cases after the anterior-posterior procedure. Five patients had a local recurrence. All recurrent lesions were malignant tumors and occurred in regions where surgical exposure was inadequate with incomplete excision. CONCLUSION: The order of the surgical approach is a critical determinant of complications, fusion rates, choice of surgical technique, and reconstruction methods. The postoperative use of a Halo-vest is recommended. Local recurrence is associated with tumor malignancy and inadequate excision margin. LEVEL OF EVIDENCE: 4.

Clinical Case Report of Expansive Laminoplasty for Cervical Myelopathy Due to Both Disc Herniation and Developmental Cervical Spinal Canal Stenosis in Older Adolescents.

Reports on adolescent patients with cervical myelopathy who underwent anterior cervical discectomy and fusion are scarce. However, to our knowledge, no cases of expansive laminoplasty for cervical myelopathy associated with progressive neurological deficit after a series of conservative treatment, caused by both disc herniation and developmental cervical spinal canal stenosis, have been reported.From January 2006 to July 2012, we retrospectively studied 3 patients in late adolescence presenting with cervical myelopathy who underwent expansive unilateral open-door laminoplasty at our hospital. The outcomes after the surgery were evaluated according to the Japanese Orthopedic Association scores.Symptoms presented by these patients were due to both disc herniation and developmental cervical spinal canal stenosis. No major complications occurred after the surgical procedures. The median follow-up time was 66 months (range 36-112 months). The Japanese Orthopedic Association scores after surgery showed a significant increase. Long-term outcomes after surgery were satisfactory according to the evaluation criteria for the Japanese Orthopedic Association scores. However, the ranges of motion of the cervical spine decreased, especially the ranges of motion on flexion after surgery showed a significant decrease.Expansive laminoplasty is helpful for older adolescent patients with cervical myelopathy due to both disc herniation and developmental cervical spinal canal stenosis, presenting with progressive neurological deficit after long conservative treatment.

Primary tumors of the spine: a review of clinical features in 438 patients.

Primary spinal tumors are rare. Current knowledge on this subject is therefore limited due to the lack of study with large cohort. This study is prompted to share our data on clinical profiles of primary spinal tumors collected from a large series of patients. Clinical manifestations of 438 consecutive patients were summarized retrospectively with statistical analysis. In the spine, benign tumor is more common than malignant. The most prevalent tumor is giant cell tumor. Tumors predominately occur between the age of 18 and 59 and the risk of malignancy increases significantly after 40. Main symptoms include local pain and neurological symptoms with frequent occurrence of neurological deficits and pathological fracture. Pain is caused by tumor expansion, pathological fracture and nerve entrapment. Occurrence of neurological deficits is significantly related to patent's age and the region of involvement. Giant cell tumor is associated with the highest incidence of neurological fracture with significance. Duration of symptom is 6 months on average. The most affected region is the cervical spine, followed by the thoracic and the lumbar spine. Tumors at the sacrum and coccyx are more likely to be malignant. Malignant tumors have significantly higher incidence of involvement at multiple levels than benign tumors. This study contributes by improving our understanding of this rare clinical entity.

Circumferential decompression via the posterior approach for the surgical treatment of multilevel thoracic ossification of the posterior longitudinal ligaments: a single institution comparative study.

BACKGROUND: The treatment strategies for multilevel thoracic ossification of the posterior longitudinal ligaments (T-OPLL) were rarely reported. The aim of this study was to investigate the clinical outcomes and complications of circumferential decompression for multilevel T-OPLL and compare two different methods in the management of the OPLL (resection or floating). METHODS: Data of sequentially treated patients who received surgical treatment for thoracic spinal stenosis caused by multilevel T-OPLL from January 2005 to February 2012 were retrospectively reviewed. Based on the surgical approaches applied, the patients were divided into two groups. Group A consisted the patients who received posterior decompression and group B consisted the patients who received circumferential decompression via the posterior approach. Group B was further divided into two subgroups: subgroup 1 (the resection group) where the OPLL was completely resected and subgroup 2 (the floating group) where the OPLL was floated. RESULTS: A total of 49 patients were included in the study. Fourteen patients with single posterior decompression were included in group A and 35 patients who received circumferential decompression were included in group B. In group B, 29 patients had complete resection of the ossified posterior longitudinal ligaments, while the other six underwent a flotation procedure. The follow-up data were available in 39 patients. Mean JOA scores improved from 5.4 ± 1.8 to 7.5 ± 2.8 in group A and from 3.7 ± 1.8 to 7.9 ± 2.4 in group B. The main complications included cerebrospinal fluid (CSF) leakage and postoperative neurologic deterioration (ND). Twenty-three of the 25 cases with postoperative CSF leakage achieved a complete recovery at the last follow-up and 12 of the 15 cases with ND achieved some neurological improvement at the last follow-up. CONCLUSIONS: Circumferential decompression via the posterior approach is an effective surgical method for thoracic spinal stenosis caused by multilevel OPLL of the thoracic spine. Patients who receive complete resection of the ossified posterior longitudinal ligaments may have better recovery rate than the "floating" group.

Chordomas of the upper cervical spine: clinical characteristics and surgical management of a series of 21 patients.

BACKGROUND: Chordomas of the upper cervical spine are rare and present unique surgical challenge. This study aimed to describe the clinical characteristics and surgical management of patients with chordomas of the upper cervical spine. METHODS: Twenty-one patients with chordomas of the upper cervical spine who were treated in Peking University Third Hospital from January 1999 to October 2012 were retrospectively analyzed. Survival was calculated by the Kaplan-Meier method and was compared between groups using the log-rank test. RESULTS: The postoperative diagnosis was classical chordoma in 20 cases and chondroid chordoma in one case. The mean operative time was 9.5 hours (range 6-17 hours), and the mean blood loss was 2 812 ml (range 700-4 800 ml). There were two postoperative deaths. Unilateral vertebral artery ligation was performed in six patients, cervical nerve roots were cut in six patients, and the external branch of the superior laryngeal nerve was repaired after being cut in one case. Two patients developed postoperative velopharyngeal incompetence, and loosening of the occipitocervical screws was observed in one patient. The recurrence rate was 66.7% (10/15) after a mean follow-up period of 46.8 months (range 14-150 months). The 5- and 10- year overall survival rates were (39.8±13.1)% and (31.9±12.7)%, respectively. There was a significant difference in survival rate between patients who underwent surgery and those who did not. CONCLUSION: In spite of the high rates of recurrence and complications after surgical treatment of chordomas of the upper cervical spine, intralesional resection combined with adjuvant radiotherapy remains the optimal treatment to prolong survival.

Novel surgical classification and treatment strategy for atlantoaxial dislocations.

STUDY DESIGN: Retrospective study of 904 patients with a diagnosis of atlantoaxial dislocation (AAD), using a novel surgical classification and treatment strategy. OBJECTIVE: To describe a novel surgical classification and treatment strategy for AADs. SUMMARY OF BACKGROUND DATA: AADs can result from a variety of etiologies, yet no comprehensive classification has been accepted that guides treatment. Because of the rarity of the cases, however, the treatment strategy has also been debated. METHODS: During a period of 12 years, a total of 904 patients with a diagnosis of AAD were recruited from a single academic institution. According to the treatment algorithm that included preoperative evaluation using dynamic radiograph, reconstructive computed tomography, and skeletal traction test, the cases were classified into 4 types: I to IV. Types I and II were fused in the reduced position from a posterior approach. Type III, which were irreducible dislocations, were converted to reducible dislocations using a transoral atlantoaxial release, followed by a posterior fusion. Type IV presented with bony dislocations and required transoral osseous decompressions prior to posterior fusion. RESULTS: Four hundred seventy-two cases were classified as type I, 160 as type II, 268 as type III, and 4 cases as type IV. Follow-up was in the range of 2 to 12 years (average: 60.5 mo). Eight hundred and ninety-nine cases (99.4%) achieved a solid atlantoaxial fusion. Anatomic atlantoaxial reduction was achieved in 892 cases (98.7%), whereas 12 cases had a partial reduction. Neurological improvement was seen in 84.1% (512/609) of the patients with myelopathy. The overall complication rate was 9.1% (82/949). CONCLUSION: Our surgical classification and treatment strategy for AADs was applied in those 904 cases and associated with excellent clinical results with a minimal risk of complications. LEVEL OF EVIDENCE: 4.

Anterior approach versus posterior approach for the treatment of multilevel cervical spondylotic myelopathy: a systemic review and meta-analysis.

PURPOSE: To compare the clinical outcomes, complications, and surgical trauma between anterior and posterior approaches for the treatment of multilevel cervical spondylotic myelopathy. STUDY DESIGN: Systematic review and meta-analysis. METHODS: We searched MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials databases for randomized controlled trials or non-randomized controlled trials that compared anterior and posterior surgical approaches for the treatment of multilevel cervical spondylotic myelopathy. Exclusion criteria were non-controlled studies, combined anterior and posterior surgery, follow-up <1 year, cervical kyphosis >15°, and cervical myelopathy caused by ossification of the posterior longitudinal ligament. The main end points included: recovery rate; Japanese Orthopedic Association (JOA) score; reoperation rate; complication rate; blood loss; and operation time. Subgroup analysis was conducted according to the mean number of surgical segments. RESULT: A total of eight studies were included in the meta-analysis; none of which were randomized controlled trials. All of the selected studies were of high quality as indicated by the Newcastle-Ottawa scale. In five studies involving 351 patients, the preoperative JOA score was similar between the anterior and posterior groups [P > 0.05, WMD: -0.00 (-0.56, 0.56)]. In four studies involving 268 patients, the postoperative JOA score was higher in the anterior group compared with the posterior group [P < 0.05, WMD: 0.79 (0.16, 1.42)]. For recovery rate, there was significant heterogeneity among the four studies involving 304 patients, hence, only descriptive analysis was performed. In seven studies involving 447 patients, the postoperative complication rate was significant higher in the anterior group compared with the posterior group [P < 0.05, odds ratio: 2.60 (1.63, 4.15)]. Of the 245 patients in the 8 studies who received anterior surgery, 21 (8.57%) received reoperation. Of the 285 patients who received posterior surgery, only 1 (0.3%) received reoperation. The reoperation rate was significantly higher in the anterior group compared with the posterior group (P < 0.001). In the 3 studies involving 236 patients compared subtotal corpectomy and laminoplasty/laminectomy, blood loss and operation time were significantly higher in the anterior subtotal corpectomy group compared with the posterior laminoplasty/laminectomy group [P < 0.05, WMD: 150.10 (63.53, 236.66) and P < 0.05, WMD: 59.17 (45.69, 72.66)]. CONCLUSION: The anterior approach was associated with better postoperative neural function than the posterior approach in the treatment of multilevel cervical spondylotic myelopathy. There was no apparent difference in the neural function recovery rate. The complication and reoperation rates were significantly higher in the anterior group compared with the posterior group. The surgical trauma associated with corpectomy was significantly higher than that associated with laminoplasty/laminectomy.

Simvastatin mobilizes bone marrow stromal cells migrating to injured areas and promotes functional recovery after spinal cord injury in the rat.

This study investigated the therapeutic effects of simvastatin administered by subarachnoid injection after spinal cord injury (SCI) in rats; explored the underlying mechanism from the perspective of mobilization, migration and homing of bone marrow stromal cells (BMSCs) to the injured area induced by simvastatin. Green fluorescence protein labeled-bone marrow stromal cells (GFP-BMSCs) were transplanted into rats through the tail vein for stem cell tracing. Twenty-four hours after transplantation, spinal cord injury (SCI) was produced using weight-drop method (10g 4cm) at the T10 level. Simvastatin (5mg/kg) or vehicle was administered by subarachnoid injection at lumbar level 4 after SCI. Locomotor functional recovery was assessed in the 4 weeks following surgery using the open-field test and inclined-plane test. At the end of the study, MRI was used to evaluate the reparation of the injured spinal cord. Animals were then euthanized, histological evaluation was used to measure lesion cavity volumes. Immunofluorescence for GFP and cell lineage markers (NeuN and GFAP) was used to evaluate simvastatin-mediated mobilization and differentiation of transplanted BMSCs. Western blot and immunohistochemistry were used to assess the expression of vascular endothelial growth factor (VEGF) and brain-derived neurotrophic factor (BDNF). Simvastatin-treated animals showed significantly better locomotor recovery, less signal abnormality in MRI and a smaller cavity volume compared to the control group. Immunofluorescence revealed that simvastatin increased the number of GFP-positive cells in the injured spinal cord, and the number of cells double positive for GFP/NeuN or GFP/GFAP was larger in the simvastatin treated group than the control group. Western blot and immunohistochemistry showed higher expression of BDNF and VEGF in the simvastatin treated group than the control group. In conclusion, simvastatin can help to repair spinal cord injury in rat, where the underlying mechanism appears to involve the mobilization of bone marrow stromal cells to the injured area and higher expression of BNDF and VEGF.

Stro-1(+) stromal cells have stem-like features in giant cell tumor of bone.

BACKGROUND: Giant cell tumor of bone (GCTB) is an aggressive benign bone tumor with poor prognosis whose neoplastic component is stromal cells (SCs). Tumor stem-like cells (TSCs) have been demonstrated as precursors for tumor genesis and growth. The aim of this study is to identify TSCs in GCTB. METHODS: Stro-1(+) and Stro-1(-) cells were isolated by fluorescence-activated cell sorting (FACS). Stem-like properties of both Stro-1(+) and Stro-1(-) subpopulations were assessed using MTT colorimetric assays, cell cycle analyses, sphere formation assays, and differentiation assays. Molecular profiles were analyzed by flow cytometry, immunofluorescence, and qRT-PCR. RESULTS: The existence of rare Stro-1(+) cells was confirmed in vitro using FACS and in vivo by immunohistochemistry. These Stro-1(+) cells exhibited higher proliferative and cisplatin-resistant potentials than Stro-1(-) cells. In serum-free suspension cultures, Stro-1(+) SCs could form cell spheres and maintain self-renewal. Furthermore, Stro-1(+) SCs could differentiate into two mesenchymal lineage cells: osteoblasts and adipocytes. Cell surface markers CD44, CD117, and CD133 and stem cell-associated genes OCT3/4, NANOG, and ABCG2 were significantly higher in the Stro-1(+) subpopulation. CONCLUSIONS: This study demonstrates that Stro-1(+) SCs in GCTB possess stem-like biological and molecular phenotypes, indicating that they are the TSCs of GCTB.

Simvastatin treatment improves functional recovery after experimental spinal cord injury by upregulating the expression of BDNF and GDNF.

The aim of this study was to determine the therapeutic efficacy of simvastatin treatment starting 1 day after spinal cord injury (SCI) in rat and to investigate the underlying mechanism. Spinal cord injury was induced in adult female Sprague-Dawley rats after laminectomy at T9-T10. Then additionally with sham group (laminectomy only) the SCI animals were randomly divided into 3 groups: vehicle-treated group; 5-mg/kg simvastatin-treated group; and 10-mg/kg simvastatin-treated group. Simvastatin or vehicle was administered orally at 1 day after SCI and then daily for 5 weeks. Locomotor functional recovery was assessed during 8 weeks postoperation by performing open-field locomotor test and inclined-plane test. At the end of study, motor evoked potentials (MEPs) and somatosensory evoked potentials (SEPs) were assessed to evaluate the integrity of spinal cord pathways. Then, the animals were killed, and 1-cm segments of spinal cord encompassing the injury site were removed for histopathological analysis. Immunohistochemistry was performed to observe the expression of brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF) in the spinal cord. Results show that the simvastatin-treated animals showed significantly better locomotor function recovery, better electrophysiological outcome, less myelin loss, and higher expression of BDNF and GDNF. These findings suggest that simvastatin treatment starting 1 day after SCI can significantly improve locomotor recovery, and this neuroprotective effect may be related to the upregulation of BDNF and GDNF. Therefore, simvastatin may be useful as a promising therapeutic agent for SCI.

Simvastatin induces estrogen receptor-alpha expression in bone, restores bone loss, and decreases ERα expression and uterine wet weight in ovariectomized rats.

We previously reported that simvastatin induces estrogen receptor-alpha (ERα) in murine bone marrow stromal cells in vitro. In this study, we investigated the effect of simvastatin on ERα expression in bone and uterus in ovariectomized (OVX) rats and evaluated bone mass, bone strength, and uterine wet weight. Three-month-old Sprague-Dawley female rats received OVX or sham operation. Six weeks later, the rats were treated orally with simvastatin (5 or 10 mg/kg/day), or intraperitoneally with 17-ß-estradiol (E(2)) or a combination of simvastatin and E(2) for 6 weeks. Uterine wet weight, bone mineral density (BMD) of lumbar vertebrae, biomechanics of lumbar vertebrae, and induction of ERα expression in the bone and uterus were analyzed. The 6-week simvastatin treatment improved lumbar vertebral BMD and boosted biomechanical performance of the vertebral body compared to the OVX control, suggesting that simvastatin can treat osteoporosis caused by estrogen deficiency. More interestingly, simvastatin could increase ERα expression and synergy with estradiol in bone while antagonizing estradiol in the uterus, along with uterus atrophy and uterine wet weight decreases. In conclusion, these data suggest that simvastatin exert opposing modulatory effects on ERα expression on bone and uterus in ovariectomized rats, inducing ERα expression and synergy with estrogen to perform anabolic effects on the bones while decreasing E2 efficacy and uterine wet weight. This finding may be helpful to explain the mechanism of statin treatment in osteoporosis caused by estrogen deficiency.

Interferon alfa-2b for recurrent and metastatic giant cell tumor of the spine: report of two cases.

STUDY DESIGN: Case report. OBJECTIVE: To demonstrate that interferon alfa-2b is a therapeutic option for obtaining long-term control of recurrent and metastatic giant cell tumor of spine. SUMMARY OF BACKGROUND DATA: Interferon alfa served as angiogenesis inhibitor and has been successfully used to treat giant cell tumor of long bones and facial bones. Up to date, no report is found with regard to the use of interferon as a stand-alone treatment for unresectable, recurrent, and metastatic giant cell tumor originated from the spine. METHODS: A 29-year-old woman with C1 and C2 giant cell tumor was treated by radiotherapy, intralesional curet, and chemotherapy orderly. Tumor recurred after 2 years. A second curet was undertaken. Tumor recurred second time and caused severe spinal cord compression. Lung metastasis was diagnosed simultaneously. A 24-year-old man with recurrent giant cell tumor of T5 and T6 was treated by spondylectomy of T5 and T6. Six months later, a giant metastatic lesion was found in sacrococcygeal region, which was excised and proved to be giant cell tumor of bone. Four months later, 2 recurrent lesions were found beside the rectum. Interferon alfa-2b at a dose of 3,000,000 U/m was then administered subcutaneously everyday for both patients for 3.5 and 3 years, respectively. RESULTS: No major complications related to the use of interferon occurred. The lesion in C1-C2 of the first patient regressed steadily and was restricted and encircled within the lateral mass. The metastatic lesions in the lungs also significantly reduced. The pararectal lesions of the second patient disappeared completely. CONCLUSION: Interferon therapy may be an effective and safe treatment for spine giant cell tumor recurrence and metastasis in soft tissue. The effectiveness may be time and dosage dependent.

Differential proteomic profiling of chordomas and analysis of prognostic factors.

BACKGROUND: The recurrence rate of chordoma is high, and the prognosis is poor. METHODS: Differential proteomic analysis was performed on chordomas and adjacent normal tissues, with verification by Western blot. Protein expression was evaluated by immunohistochemistry of 37 chordomas. Association of candidate protein expression with clinical parameters, disease-free survival, and overall survival were analyzed. RESULTS: We identified 14 up-regulated and 5 down-regulated proteins in chordomas. Expression of alpha enolase (ENO1), pyruvate kinase M2 (PKM2), and gp96 was higher in recurrences than in primary tumors. Univariate analysis showed that significantly adverse factors for disease-free survival were overexpression of ENO1 and PKM2, involvement of contiguous vertebral levels, and inadequate surgical margin at initial surgery. Inadequate surgical margin without radiotherapy, involvement of contiguous vertebral levels, and cervical spine location were adverse factors for overall survival. By multivariate analysis, independent adverse prognostic factors were inadequate surgical margin and involvement of multiple contiguous vertebral levels for recurrence; upper cervical spine location and involvement of contiguous vertebral levels for tumor-related death. Multivariate analysis failed to show the significance of the proteins. CONCLUSIONS: Involvements of multiple contiguous vertebral levels and upper cervical spine, rather than overexpression of ENO1, PKM2, or gp96, are independent prognostic indicators for chordomas.

[Analysis of veracity of the C1 lateral mass screw insertion in the atlantoaxial fixation].

OBJECTIVE: To evaluate the veracity of the C1 lateral mass screw insertion in the atlantoaxial fixation using plate and screw method without A-P fluoroscopic guiding. METHODS: In the atlantoaxial fixation, without A-P fluoroscopic guiding, we probe lateral mass edge and identify the entrance point of C1 lateral mass screw indirectly. 159 patients treated with atlantoaxial fixation using plate and screw method were studied. Postoperative CT was used for analysis, and the position of the lateral mass screws in atlas was identified by coronary and axial CT scan. Three areas were delimited in and around the lateral mass of atlas in the axial CT scan, so as to analyze the location of screws: area A (inside the joint face), area B (outside the joint face but still in lateral mass), and area C (outside the lateral mass). RESULTS: Among the 318 screws, 308 (96.9%) were located in area A, 5 in area B (1.6%), and 5 in area C (1.6%). All cases got atlantoaxial union at 4 months after operation. CONCLUSION: Probing lateral mass edge and identifying the lateral mass indirectly is reliable for identifying the path of screw in atlas.

Simvastatin induces estrogen receptor-alpha (ER-alpha) in murine bone marrow stromal cells.

Simvastatin has been shown to stimulate osteogenesis both in vitro and in vivo. However, the mechanism by which simvastatin exerts its effects is still unclear. We previously reported that simvastatin promotes bone morphogenetic protein 2 (BMP-2) expression, induces osteoblastic differentiation, and inhibits adipocytic differentiation in mouse bone marrow stromal cells (BMSCs), and that this occurs, at least in part, via a BMP-2-dependent pathway. The aim of this study was to investigate further the mechanisms by which simvastatin stimulates osteogenesis in mouse BMSCs. To determine whether simvastatin-mediated osteogenesis was dependent on BMP-2, mouse BMSCs were treated with nonimmune normal mouse IgG or BMP-2 neutralizing antibodies combined with different concentrations of simvastatin. Surprisingly, the stimulatory effect of simvastatin on alkaline phosphatase (ALP) activity was not completely blocked by neutralizing BMP-2 monoclonal antibody treatment. Interestingly, we found that estrogen receptor-alpha (ER-alpha) protein levels increased after mouse BMSCs were treated with simvastatin for 72 h in a concentration-dependent manner. Moreover, the stimulatory effect of simvastatin on ALP activity in BMSCs was blocked by the estrogen receptor agonist ICI 182,780, and cotreatment with 17-beta-estradiol and simvastatin increased ALP activities by two-to threefold in the BMSCs compared with treatment with simvastatin alone. These results suggest that simvastatin-induced in vitro osteogenesis in mouse BMSCs is mediated, at least in part, by induction of ER-alpha and not by BMP-2 alone. These results provide new insight into the mechanisms of simvastatin-induced bone formation in BMSCs.

[Qualitative diagnosis and therapeutic strategy of atlanto-axial tuberculosis].

OBJECTIVE: To investigate the qualitative diagnosis method of atlanto-axial tuberculosis and the corresponding therapeutic strategy. METHODS: Twenty-two cases with atlanto-axial tuberculosis proven by histopathologic diagnosis were observed. Three cases and 17 cases underwent trans-oral biopsy and CT-guide percutaneous biopsy respectively, 2 cases were conformed by frozen section in operation. Thirteen of the 22 cases underwent surgical therapy: 1 case with anterior trans-oral radical eradication and fusion under Halo-vest immobilization, 7 cases with anterior cervical radical eradication, 1 case with anterior interbody fusion and titanic plate fixation, 2 cases were with posterior atlantoaxial interlaminar fusion and 2 cases with posterior cervical occipito-axial titanic plate internal fixation and fusion. Other 9 cases accepted nonsurgical therapy: 8 cases with Halo-vest immobilization and 1 case with head halter traction. All cases were given appropriate antituberculotic chemotherapy for 12-18 months. RESULTS: All of the 22 cases were followed up, and the average time was 37 month. The lesion focus showed reparation and fusion in X-ray, and the results were satisfactory. CONCLUSIONS: Biopsy can acquire the qualitative diagnosis on atlanto-axial tuberculosis. The choice of therapy is made on the situation of cold abscess, pathological fracture, atlanto-axial dislocation and spinal cord compression.

Atlantoaxial transarticular screw fixation with morselized autograft and without additional internal fixation: technical description and report of 57 cases.

STUDY DESIGN: Retrospective clinical and radiologic evaluation of posterior C1-C2 fusion by transarticular screw (TAS) with morselized autograft and without additional internal fixation. OBJECTIVE: Description and assessment of a modified Magerl technique. SUMMARY OF BACKGROUND DATA: The majority of spine surgeons prefer to supplement the posterior TAS with a posterior cable-secured strut graft and a postoperative rigid cervical orthosis. Our hypotheses are that the 2 posterior TASs alone are enough for stabilization and that morselized cancellous grafts have similar clinical result as the structural graft. METHODS: Fifty-seven consecutive patients, including atlantoaxial instability in 52 and atlantoaxial dislocation in 5, were treated by bilateral TAS fixation alone with morselized grafts by the same surgeon. The postoperative external immobilization was abandoned. RESULTS: A total of 114 transarticular screws were placed. Radiographs demonstrated all the screws were placed satisfactorily except two. One screw penetrated into the occipito-atlantal joint, and the other one slightly breached the vertebral artery groove but did not injure vertebral artery. None of these 2 screws was associated with clinical sequelae. There were 2 patients who had postoperative iatrogenic C2-C3 instability on dynamic radiograph, which did not need treatment. These cases had an average follow-up of 47 months (range, 24-76 months). All patients attained solid fusion without screw failure. CONCLUSIONS: Bilateral transarticular screws alone and morselized grafts have high fusion rate in atlantoaxial arthrodesis without instrument failure. TAS fixation could provide stability that is clinically equivalent to the standard screws plus tension band construct as described by Magerl. With anatomic reduction and ideal screw position, additional internal fixation and postoperative collar are not necessary.

Icariine stimulates proliferation and differentiation of human osteoblasts by increasing production of bone morphogenetic protein 2.

BACKGROUND: Icariine is a flavonoid isolated from a traditional Chinese medicine Epimedium pubescens and is the main active compound of it. Recently, Epimedium pubescens was found to have a therapeutic effect on osteoporosis. But the mechanism is unclear. The aim of the study was to research the effect of Icariine on the proliferation and differentiation of human osteoblasts. METHODS: Human osteoblasts were obtained by inducing human marrow mesenchymal stem cells (hMSCs) directionally and were cultured in the presence of various concentrations of Icariine. 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) test was used to observe the effect of Icariine on cell proliferation. The activity of alkaline phosphatase (ALP) and the amount of calcified nodules were assayed to observe the effect on cell differentiation. The expression of bone morphogenetic protein 2 (BMP-2) mRNA was detected by reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS: Icariine (20 microg/ml) increased significantly the proliferation of human osteoblasts. And, Icariine (10 microg/ml and 20 microg/ml) increased the activity of ALP and the amount of calcified nodules of human osteoblasts significantly (P < 0.05). BMP-2 mRNA synthesis was elevated significantly in response to Icariine (20 microg/ml). CONCLUSIONS: Icariine has a direct stimulatory effect on the proliferation and differentiation of cultured human osteoblast cells in vitro, which may be mediated by increasing production of BMP-2 in osteoblasts.

Treatment of cervical dislocation with locked facets.

BACKGROUND: Lower cervical dislocation with locked facets is common in cervical injury. The locked facets include unilateral and bilateral types. Different successful closed reduction rates has been achieved between unilateral and bilateral types by using rapid skull traction, which was commonly used to reduce the cervical dislocation. It is important to investigate a suitable management specific to patients with different types of cervical locked facets. METHODS: A total of 38 patients with cervical dislocation with locked facet due to cervical injury treated by rapid skull traction and operation from 1988 to 2005 were reviewed. Rapid skull traction was used in all the patients. Successful closed reduction rate was 88.0% in patients with bilateral cervical locked facets and that was 15.4% in those with unilateral cervical locked facets. These data were then statistically compared by Chi-square test. Patients who were reduced successfully underwent anterior cervical discectomy and fusion at the injured level, and those who failed in closed reduction received posterior open reduction and fixation. RESULTS: In this series, there was statistically significant difference (P < 0.05) in the rate of successful closed skull traction reduction between unilateral and bilateral locked facets dislocation. Unilateral cervical locked facets dislocation was not easily reduced by skull traction which was suitable for reduction of bilateral cervical locked facets dislocation. However, unilateral cervical locked facets dislocation can be reduced by posterior open reduction. CONCLUSIONS: Unilateral cervical locked facets dislocation should be treated immediately with posterior open reduction and instrumentation. Bilateral cervical locked facets dislocation can be reduced by rapid skull traction firstly and anterior cervical discectomy and interbody fusion later.

[Single-stage combined anterior-posterior instrumentation for multiple level cervical spine fractures].

OBJECTIVE: To investigate the efficacy of single-stage combined anterior-posterior instrumentation for treatment of multiple level cervical spine fractures. METHODS: Nine patients with multiple-level fractures of the cervical spine, 8 males and 1 female aged 24 - 63, underwent ingle-stage combined anterior-posterior instrumentation. Seven patients with multiple contiguous fractures of the cervical spine were treated with anterior decompression and plating combined with posterior cervical lateral mass screw fixation; and 2 patients with non-contiguous cervical fractures, both with type II odontoid fracture and lower cervical fracture, were treated with both anterior odontoid screw and posterior cervical lateral mass screw fixation. Cranioskeletal traction with a weight of 5 kg was done before the operation. Follow-up was conducted for 31 months. ASIA motor scores were used to evaluate the neural function. RESULTS: Satisfactory reduction and fusion were obtained without any complication, and the neural function was improved. Nerve root function recovered in two patients and one patient's spinal cord function became normal. The average ASIA score was 63.8. CONCLUSION: A feasible option in the treatment of multiple level cervical spinal fractures, single-stage combined anterior-posterior instrumentation provides decompression and stabilization in a short time and helps the neural function to recover.