[Stable isotopes of zooplankton and their applications in the research of aquatic ecosystems]. / æµ®æ¸¸åŠ¨ç‰©ç¨³å®šç¢³ã€æ°®åŒä½ç´ ç‰¹å¾åŠå ¶åœ¨æ°´ç”Ÿæ€ç³»ç»Ÿç ”ç©¶ä¸­çš„åº”ç”¨.

Zooplankton plays a mediating role in the food web of aquatic ecosystems, the stable carbon and nitrogen isotopes (δ13C and δ15N) of which have been widely used to study the utilization of food resources, material cycling pathways, and trophic relationships. The δ13C and δ15N values of zooplankton have been used to predict primary productivity, sources and sinks of pollutants and environmental changes. To better use δ13C and δ15N of zooplankton as ecological and environmental indicators, it is particularly important to understand their temporal and spatial variations and the influencing factors. Based on related literature, we synthesized spatial and temporal variations in δ13C and δ15N of zooplankton in different aquatic ecosystems and taxa groups, and the use of δ13C and δ15N indicators for ecological processes and environmental changes. The δ13C and δ15N of zooplankton are largely affected by its food sources, and its stable isotope compositions are in turn affected by primary productivity and nitrogen sources. We proposed that the combination of δ13C and δ15N in zooplankton with transportation and transformation of emerging pollutants would form a multi-means, multi-disciplinary and multi-scale research direction in the fields of earth science and biology.

Expression and clinical significance of periostin in oral lichen planus.

Oral lichen planus (OLP) is a chronic inflammatory lesion involving the oral mucosa, which has a high likelihood of progressing to cancer. The present study investigated the periostin expression in the mucosa and serum of patients with OLP and its correlation with serum cytokines. A total of 117 patients with OLP and 110 healthy controls were included in the study. The protein expression of periostin were measured in the OLP and normal oral mucosa by immunohistochemistry. ELISA was performed to measure the serum levels of periostin, tumour necrosis factor-α (TNF-α), interleukin (IL)-6, interferon-γ (IFN-γ), IL-4 and thymic stromal lymphopoietin (TSLP). Compared with the control group the OLP group had a significantly increased number of cases with high periostin expression in the oral mucosa and a significantly increased serum periostin level (P<0.05). Among all 117 OLP subjects, high periostin expression was associated with higher serum IL-6, TNF-α, TSLP and tissue mast cell density. High periostin expression was also significantly associated with a lower IFN-γ/IL-4 ratio (P<0.05). The present study concluded that periostin expression was increased in the oral mucosa and serum of patients with OLP and was associated with inflammatory response, T helper 2 cytokine-predominant immune imbalance, increased mast cell count and TSLP. The modulation of periostin may represent an attractive novel therapeutic target.

[Mini-open trans-spatium intermuscular versus percutaneous short-segment pedicle fixation for the treatment of thoracolumbar mono-segmental vertebral fractures].

OBJECTIVE: To compare the clinical effects and radiographic outcomes of mini-open trans-spatium intermuscular and percutaneous short-segment pedicle fixation in treating thoracolumbar mono-segmental vertebral fractures without neurological deficits. METHODS: From August 2009 and August 2012, 95 patients with thoracolumbar mono-segmental vertebral fractures without neurological deficits were treated with short-segment pedicle fixation through mini-open trans-spatium intermuscular or percutaneous approach. There were 65 males and 30 females, aged from 16 to 60 years old with an average of 42 years. The mini-open trans-spatium intermuscular approach was used in 58 cases (group A) and the percutaneous approach was used in 37 cases (group B). Total incision length, operative time, intraoperative bleeding, fluoroscopy, hospitalization cost were compared between two groups. Visual analog scale (VAS) and radiographic outcomes were compared between two groups. RESULTS: All patients were followed up from 12 to 36 months with an average of 19.6 months. No complications such as incision infection, internal fixation loosening and breakage were found. In group A, fluoroscopy time was short and hospitalization cost was lower than that of group B (P<0.05). But the total incision length in group B was smaller than that of group A (P<0.05). There was no significant differences in operative time, intraoperative bleeding, postoperative VAS and radiographic outcomes between two groups (P>0.05). Postoperative VAS and radiographic outcomes were improved than that of preoperative (P<0.05). CONCLUSION: The mini-open trans-spatium intermuscular and percutaneous short-segment pedicle fixation have similar clinical effects and radiographic outcomes in treating thoracolumbar mono-segmental vertebral fractures without neurological deficits. However, in this study, the mini-open trans-spatium intermuscular approach has a short learning curve and more advantages in hospitalization cost and intraoperative radiation exposure times, and is recommendable.

[Treatment of flexion-distraction thoracolumbar fractures by postural reduction with instrumental reduction].

OBJECTIVE: To study the curative effect of postural reduction with instrumental reduction in treatment of flexion-distraction thoracolumbar fractures. METHODS: A retrospective study was performed on 43 patients with single thoracolumbar flexion-distraction fractures admitted from August 2009 to August 2011, included 28 males and 15 females with an average age of 44 years old (34 to 56 years old). All patients were treated with postural reduction with instrumental reduction. The kyphosis (Cobb angle) recovery of injured vertebral height and complication were analyzed. The visual analogue scale(VAS) and com-plications were followed up and recorded. RESULTS: There was no difference in recovery of injured vertebral posterior height among preoperative, 1 week and 1 year after operation (P > 0.05). There were significantly difference in kyphosis (Cobb angle) and recovery of injured vertebral anterior height between preoperative and postoperative at 1 week (P < 0.05). There was no difference in kyphosis (Cobb angle) and recovery of injured vertebral anterior height between 1 week and 1 year after operation (P > 0.05). VAS significantly improved from preoperative (7.2 +/- 1.2) to (0.8 +/- 0.7) at 1 year after operation (t = 18.47, P < 0.001). CONCLUSION: Postural reduction with instrumental reduction is effective for thoracolumbar flexion-distraction fractures and it is beneficial to the recovery of vertebral height and saggital alignment.

[Analysis of epidural hematoma formative reason and its preventive measure after anterior cervical operation].

OBJECTIVE: To explore the risk factors,preventive measure of epidural hematoma after anterior cervical operation. METHODS: From June 2005 and December 2012, 1,452 patients underwent anterior cervical operation in our hospital. Epidural hematoma occurred in 5 cases after operation and the incidence rate was 0.34%. There were 4 males and 1 female with an average age of 46.4 years (ranged, 33 to 55); 3 cases with cervical myelopathy, 1 case with cervical myelopathy and C5 vertebral angeioma, 1 case with ossification of cervical posterior longitudinal ligament. The occurred time,main clinical situation,duration of symptoms,operative management of epidural hematoma were analyzed. RESULTS: Five patients with epidural hematoma occurred within 24 h; the average interval between onset of symptoms and surgery was 4 h (ranged, 2 to 7). Operative treatment was accomplished in 5 cases by exploration and hematoma evacuation. There was significant improvement in all patients after reoperation. Epidural hematoma occurred again in one patient at 5 h after hematoma evacuation, and reoperation were performed to treat it. All patients were followed up from 6 to18 months with an average of 13.8 months. No recurrence was found. CONCLUSION: Intensive care in 24 h postoperatively is important because of epidural hematoma often occurs in this period,especialy in the period of 6-8 h postoperativey. Clinical findings and MRI can early diagnose epidural hematoma and help treatment. Once it is identified and surgical evacuation would be performed on time.

[Transoral plate internal fixation for treatment of instability atlas fracture].

OBJECTIVE: To evaluate the efficacy and safety of transoral plate internal fixation for instability atlas fracture. METHODS: A retrospective study was performed in eight patients with instability atlas fractures, who were treated by a transoral plate internal fixation from July 2007 to June 2011. There were 6 males and 2 females,with an average age of 39.5 years old ranging from 23 to 48 years. Among them, 5 case were falling injury, 3 cases were traffic accident injury. Three patients had bilateral fractures of the anterior arch (prehalf Jefferson fractures, Landells type I), 5 had anterior are fracture associated posterior are fracture (Half-ring Jefferson fractures, Landells type II), and 2 had anterior and posterior are fracture associated with single lateral mass fractures (Landells type III). RESULTS: All patients were followed up for 6 to 24 months after operation (av- eraged 13 months), and all the patients had the clinical symptoms improved to some extent. Operation time ranged from 80 to 140 min (averaged 98 min); the intra-operative blood loss was 120 to 300 ml (averaged 180 ml); and the average fluoroscopic time was 55 s. No patients happened neurological and vertebral artery injuries-related complications or other complications after operation. The followed-up X-ray and CT manifested osseous fusion in all the 8 patients,no loosening or breakage of the screws. CONCLUSION: Transoral plate internal fixation for instability atlas fracture is a reliable and safety technique that allows maintenance of rotatory mobility in the C1,2 joint and restoration of congruency in the atlanto-occipital and atlanto-axial joints.

[Clinical application of lower cervical spinous process laminar screw technique in open door laminoplasty].

OBJECTIVE: To investigate the clinical outcomes of lower cervical spinous process laminar screw technique in open door laminoplasty. METHODS: From February 2005 to June 2010,12 patients with cervical myelopathy were treated with open door laminoplasty by lower cervical spinous process laminar screw technique. There was intervertebral disc herniation with degenerative stenosis in 5 patients, ossification of posterior longitudinal ligament with osteophyte in 6 patients, cervical traumatic instability with spinal cord injuries in 1 patient. Nerve function, complications, and the cervical canal to body ratio (CBR), range of motion (ROM) and the anteroposterior serial alignment were observed by Japanese Orthopedic Association (JOA) score, X-ray, CT and MRI. RESULTS: The surgical time was from 1.5 to 2 h with an average of 110 min; blood loss during operation was from 450 to 800 ml with an average of 580 ml. Postoperative complication occurred in 1 case with upper limb pain and 1 case with cerebrospinal fluid leakage. All patients were followed up from 1 to 2 years with an average of 21.8 months. JOA score improved from preoperative 9.5 +/- 1.8 to postoperative 13.6 +/- 2.4 (P < 0.01). X-ray, CT, MRI showed CBR increased obviously (P < 0.01); ROM on flexion-extension and cervical lordosis decreased respectively from (40.0 +/- 10.0) degrees and (65.0 +/- 12.0)% before operation to (15.0 +/- 5.0) degrees and (42.0 +/- 8.0) % at the final follow-up (P < 0.01). CONCLUSION: Lower cervical spinous process laminar screw technique in open door laminoplasty for cervical syndrome is safe and can obtain satisfactory effects, has strong internal fixation and reduce the risk of re-closure.

[Anatomic study of lower cervical spinous process for laminar screw fixation].

OBJECTIVE: To measure anatomic data of spinous process and vertebral plate and evaluate the possibility of fixation of spinous process and vertebral plate. METHODS: Twenty cadaveric cervibal spines of C3-C7 were dissected to expose vertebral plate and spinous process, and were measured by two methods, one was manual measured using digital caliper and the other was computed tomography scaning. Parameters were measured manually including vertebral plate height and width. The screw was inserted from the boundary of the vertebral plate and spinous process, and gone out from the top of vertebral plate back of opposite side. Then through the CT reconstruction, angle of screw insertion, length of screw trajectory and distance between the screw tip and vertebral artery and spinal cord were measured. Additionally, spinous process width and vertebral plate thickness of 100 patients' CT scans of C3-C7 cervical segment were measured to evaluate possibility of screw insertion at spinous process and vertebral plate. RESULTS: The screw fixation of lower cervical spinous process and vertebral plate were successfully placed,without impingement of spinal cord and vertebral artery. There was no statistic difference on the data of lamina height and width of 20 cadaver specimens between manual and CT measurements (P>0.05). Height and width of vertebral plate was (12.4 +/- 1.2) to (13.7 +/- 1.3) mm and (4.5 +/- 0.9) to (5.4 +/- 1.1) mm respectively and increased gradually from C3 to C7 (P<0.05). The trajectory length was (13.7 +/- 1.2) to (15.8 +/- 1.8) mm and increased gradually from C3 to C7 (P<0.05). The distance between screw tip and vertebral artery and spinal cord was (20.1 +/- 2.7) to (25.8 +/- 2.9) mm and (4.1 +/- 1.8) to (5.0 +/- 1.2) mm respectively. The angles of screws insertion were (73.0 +/- 9.9) degrees to (85.3 +/- 10.1) degrees in the axial plane (P>0.05). Based on the CT measurements of 100 patients,the data of the spinous process width and lamina thickness varied from a minimum of (8.5 +/- 1.1) mm and (4.3 +/- 0.5) mm for the C4, to a maximum of (14.5 +/- 2.0) mm and (6.0 +/- 1.1) mm for the C7 respectively. CONCLUSION: Lower cervical spinous process and vertebral plate screw fixation is feasible, which is a safe and stable screw approach for spinous process and vertebral plate fixation.

[Micro-endoscopic discectomy for the treatment of lumbar disc herniation in senile patients over seventy years old].

OBJECTIVE: To explore applicability and therapeutic effects of Micro-endoscopic discectomy (MED) for the treatment of lumbar disc herniation in senile patients over seventy years old. METHODS: Thirty-two patients over seventy years old with lumber disc herniation were treated by MED from December 2007 to June 2010. Among them,20 patients were male and 12 patients were female,ranging in age from 70 to 86 years, with an average of 78.5 years old. The course of diseases ranged from 2 weeks to 30 years, with an average of 3.5 years. The main clinical symptoms were low back pain with radiating pain in lower extremities, especially under the keen joint. The surgical time, blood loss, complications and function recovery were evaluated retrospectively immediately after operation. X-ray at 1 week after operation was used to observe the change of physical curvature of lumbar; MRI at 1 month after operation was used to observe the radiographic change of lumbar before and after treatment; MacNab standard was applied to evaluate the therapeutic effects at 3 months after operation. RESULTS: The mean follow up period was 12.5 months (from 3 to 30 months). The mean operative time was 60 min (from 30 to 120 min) and the mean blood loss was 45 ml (from 15 to 150 ml). Leakage of cerebrospinal fluid occurred in 1 case, the operation continued after pressing by brain cotton and without nerve root and vessels injury; 1 case aggravated after revive, but other patients were eased. X-ray at 1 week after operation showed physical curvature of lumbar of 25 patients improved; MRI at 1 month after operation showed residue intervertebral disc and calcification tissue in 8 cases. Eleven patients still had numbness of limbs,but the pain and tenderness of limbs relieved. According to MacNab standard at 3 months after operation, 25 cases got an excellent result (78.1%), 6 good (18.8%) and 1 fair (3.1%). CONCLUSION: MED is effective for the senile patients over 70 years old with lumbar disc herniation and promotes ambulation earlier. MED has the advantage of minimal invasive, less blood loss and good clinical effects; MED is suitable for the patients with obvious radiating pain in lower extremities, especially under the keen joint and combine with mild spinal stenosis and root stenosis.

[Anatomic comparison between spinous process screws and pedicle screws techniques of the second cervical vertebar].

OBJECTIVE: To compare anatomic difference between spinous process screws and pedicle screws techniques of the second cervical vertebra. METHODS: Ten human cadaveric of cervical spine (5 male, 5 female) were harvested and had no gross deformities such as scoliosis and/or kyphosis were found in the study. The average age of the subjects was 60.5 years. The specimens were placed in the prone position. Posterior cervical exposure was attained by dissecting all soft tissue off the posterior aspect of the second cervical vertebra. After clear exposure of the lateral mass,the spinous process screw and pedicle screw insertion techniques were performed in this study. Each technique involved ten specimens and 10 screws inserted into C2 bilaterally. The one side of C2 was randomly selected for the spinous process screw and the other side was designate for the pedicle screw. This point then was drilled with a 3 mm drill, and followed by placement of a 4.0 mm cortical screw. The starting point for spinous process screw insertion was located at the junction of the lamina and the spinous process and the direction of the screw was about 0 degrees caudally in the sagittal plane and about O0 medially in the axial plane. The starting point of pedicle screw should be the midpoint of the base of inferior articular facet of the axis. The drilling angle was 15 degrees to 20 degrees in the superior direction and 30 degrees in the medial direction. After screw placement, all the specimens were CT scaned. On the CT scan,the length of the spinous process screw and pedicle screw trajectory were measured. Results were recorded for each screw that violated impinged of the pedicle, spinal canal and transverse process foramen. RESULTS: All the C2 spinous process screws were successfully placed, without impingement the spinal cord, the vertebral artery and the breakage of the spinous process. There was one pedicle screw breaking the pedicle into the vertebral artery foramen. The trajectory length for the spinous process screws were (21.4 +/- 1.4) mm,compared with the pedicle screws (23.7 +/- 1.0) mm. But there was no significant differences between spinous process screws and pedicle screws techniques (t = -4.387, P > 0.05). CONCLUSION: The C2 spinous process screw fixation has the anatomic feasibility and is easier to perform than pedicle screw fixation.

NF-κB induces abnormal centrosome amplification by upregulation of CDK2 in laryngeal squamous cell cancer.

Centrosome amplification can drive chromosomal instability (CIN) which is a major source of tumor initiation. The present study aimed to investigate the impact of nuclear factor kappa B (NF-κB) on centrosome amplification of Hep-2 cells. Immunofluorescence was performed to display centrosomes. BAY11-7082 was used as an inhibitor of NF-κB to assess the inhibition of centrosome amplification, and cyclin-dependent kinase 2 (CDK2), ensuring cell cycle cycle coordination with centrosome cycle was detected by Western blotting. Furthermore, a 1556-bp fragment of the CDK2 promoter was analyzed using the TRANSFAC-TESS software. Luciferase assay, including a series of truncated CDK2 promoters and site mutations, was carried out to determine NF-κB binding sites in the CDK2 promoter. Electrophoresis mobility shift and chromatin immunoprecipitation assays were applied to confirm whether NF-κB indeed binds to the 5'-promoter region of the CDK2 gene. To reveal the clinical significance of CDK2 expression in laryngeal squamous cell cancer, mRNA and protein levels were assessed by RT-PCR and Western blotting, respectively. We found that the transcription factor NF-κB plays a role in centrosome amplification in Hep-2 cells. Centrosome amplification is reduced by inhibition of the NF-κB pathway. Moreover, expression of the p65 subunit of NF-κB is sufficient to promote centrosome amplification and increase in CDK2 protein levels. We further identified a functional NF-κB binding site located in the CDK2 promoter. Single mutation of the NF-κB site III (construct mutIII) however resulted in 76±5% (p<0.01) luciferase activity reduction. Electromobility shift assays and chromatin immunoprecipitaton results suggest that NF-κB indeed binds to this responsive element associating with CDK2 expression and centrosome amplification. RT-PCR and Western blotting results revealed that both mRNA and protein levels of CDK2 were significantly higher in tumor tissues than those in paired adjacent normal laryngeal tissues.

[Effect of exogenous adrenomedullin on renal and hypothalamus adrenomedullin expression in rats early after mechanical renal trauma].

OBJECTIVE: To observe the effects of exogenous adrenomedullin (ADM) on endogenous expression of ADM in the kidney and hypothalamus of rats early after mechanical renal trauma. METHODS: Adult Wistar rats were randomized into 4 groups (n=32), namely the control group, renal impact trauma group, preventive ADM injection group, and therapeutic ADM injection group. In the latter two groups, ADM (0.1 nmol/kg) was administrated by intraperitoneal injection 10 min before and 10 min after renal trauma. The rats were executed at 1, 6, 12, and 24 h after the trauma to examine the expression of ADM in the kidney and hypothalamus. RESULTS: In preventive ADM injection group, the renal expression of ADM increased significantly at 1 h after the trauma (P<0.05) and tended to further increase with time till 24 h when its expression recovered the normal level. In the therapeutic ADM injection group, strong renal ADM positivity was found at 1 and 6 h after the injury (P<0.05) followed by gradual decrease till recovering the normal level at 24 h. Low renal ADM expression was detected, which was the strongest at 1 and 12 h (P<0.05) and became normal at 24 h. The time course of ADM expression in the hypothalamus was similar to that in the kidney in the therapeutic ADM injection group, and in the preventive injection group, the strongest ADM expression in the hypothalamus occurred at 6 and 24 h, and the lowest expression occurred at 12 h (P<0.05). The trauma group showed significantly decreased ADM expression in the hypothalamus compared with the control group (P<0.05). CONCLUSION: The hypothalamic ADM expression can upregulate renal ADM expression. ADM maintains the relative stability of the internal environment and physiological activity by local and systemic positive and negative feedback mechanisms.

[Study on the feasibility of posterior thoracic transarticular screw fixation].

OBJECTIVE: To study the feasibility and technical parameters of posterior transarticular screw fixation in the thoracic spine. METHODS: Since September 2009 to December 2009, 20 thoracic cadaveric spines (12 males and 8 females) were dissected. The lateral masses and pedicles were exposed carefully. After the entrance point of transarticular screws was determined, posterior transarticular screws implantation was performed under direct visualization into T(1,2), T(5,6) and T(9,10). Then CT scan was performed. On the CT scan,the angle and length of the transarticular screw trajectory were measured. RESULTS: The thoracic transarticular screw trajectory were caudal tilting in the sagittal plane and lateral tilting in the coronal plane with successful placement. There was little differences between different segmental of thoracic vertebrae of the angle, but without significance (P > 0.5). The average angles of the screws were (52.6 +/- 5.9) degrees caudal tilting in the sagittal plane and (12.4 +/- 2.9)0 lateral tilting in the coronal plane. The average trajectory lengths were (22.5 +/- 1.9) mm. There was significant differences statistically among T(1,2), T(5,6) and T(9,10) (P < 0.01). CONCLUSION: Posterior transarticular screw fixation is feasible. Transarticular screw fixation in the thoracic spine affords an alternative to standard pedicle screw placement for thoracic stabilization.

[An anatomic study of posterior C(2) spinous process laminar screw fixation].

OBJECTIVES: To explore the feasibility and the technical parameters in posterior C2 spinous process laminar screw fixation, and discuss the clinic significance of C2 spinous process laminar screws. METHODS: Twenty cervical cadaveric spines of C2 were dissected, with care taken to expose the lamina and spinous process. After the entrance point of spinous process screw were determined, posterior C2 spinous process laminar screw implantation was performed under visual control. On the morphologic CT scan, the angle and length of the spinous process laminar screw trajectory and the distance between the tip of the screw and the spinal cord and the vertebral artery were measured. RESULTS: The C2 spinous process laminar screws were successfully placed, without impingement of the spinal cord and the vertebral artery. There were little differences between superior and inferior screws in the angle, trajectory length and the distance between the tip of the screw and the spinal cord and the vertebral artery, but without significance (P > 0.05). The placed angles of the screws were 76.8° ± 10.6° in the axial plane. The distance between the tip of the screw and the spinal cord and the vertebral artery was (5.3 ± 1.6) mm and (17.4 ± 3.7) mm respectively. The trajectory length was (23.1 ± 3.2) mm. CONCLUSIONS: Posterior C2 spinous process laminar screw fixation is feasible. C2 spinous process laminar screw fixation affords an alternative to standard screw placement for plate fixation and cervical stabilization.

[Clinical observation of mid-stage complications after cervical disc replacement].

OBJECTIVE: To summarize the therapeutic experience of Bryan prosthetic cervical disc replacement at the 3rd years after operation and to analyze the clinical effect, incidence rate of heterotopic ossification, conditions of prosthetic fusion in order to investigate the countermeasures. METHODS: From December 2005 to December 2008, 54 patients with cervical syndrome (34 males and 20 females, the age was from 39 to 69 years with an average of 50.5) were treated with single level Bryan prosthetic cervical disc replacement. The patients were followed for 24-36 months with an average of 30 months. The symptoms and nerve function were evaluated according to JOA and Odom's scoring. The anterior-posterior and lateral cervical X-ray films were also taken regularly every three months for the observation of heterotopic ossification and prosthetic fusion. Meanwhile, the X-ray films of the forward bending, extending, left and right lateriflection were taken before operation and at the 1st years after operation for the measurement of the stability and rang (ROM) of replaced levels. RESULTS: The pain symptom and neurological function of all 54 patients were improved obviously. JOA score increased with an average of 76.1%, and ROM of replaced levels also improved obviously. The incidence rate of heterotopic ossification and prosthetic fusion went up year by year, 3.7% (2/54) for the first year, 16.7% (9/54) for the second year and 22.2% (12/54) for the nearly third year. CONCLUSION: Bryan prosthetic cervical disc replacement has better mid-stage results than conventional methods. Modified surgical methods and early rehabilitation exercise may reduce the relatively high incidence rate of heterotopic ossification and prosthetic fusion.

[Biomechanical study on transarticular screw and plate fixation syetem in the lower cervical spine].

OBJECTIVE: To compare the cervical stabilities of transarticular screw fixation alone, and transarticular screw and plate fixation system. METHODS: Twelve specimens of cervical vertebra containing C2-T1 were obtained from human cadaver. The three-column instability model was made at C4.5 and C5.6 levels. The specimens were stabilized with transarticular screw fixation alone, and transarticular screw and plate fixation system respectively. The ranges of motion of segments including intact group, transarticular screw fixation alone group and transarticular screw and plate fixation system group were measured under the torque of 2.0 N x m in flexion, extension, lateral bending, and torsion respectively under nonrestrictive and nondestructive condition. RESULTS: The rang of motion (ROM) and neutral zone (NZ) of both transarticular screw fixation alone and transarticular screw and plate fixation system group were significantly smaller than those of intact group in all directions (P < 0.05). The transarticular screw and plate fixation system group allowed a very smaller ROM and NZ than transarticular screw fixation alone during extension, lateral bending and axial rotation except flexion (P < 0.05). CONCLUSION: Cervical transarticular screw and plate fixation system provides better stability than transarticular screw fixation alone. If the transarticular fixation technique is preferred, transarticular screw and plate fixation system will be beneficial.

[Anatomical considerations for the placement of C2 spinous process screws].

OBJECTIVES: To quantitatively anatomically evaluate the C2 spinous process, analyze the anatomical feasibility of the C2 spinous process screws and its clinical significance. METHODS: To dissect and evaluate 30 cervical cadaveric spines of C2 which were taken to expose the lamina and spinous process. Anatomic quantitative evaluation of the C2 spinous process included its height and width. Twenty cervical cadaveric spines of C2 were chosen to the study of the placement of the C2 spinous process screws. The starting point for the C2 spinous process screw insertion was located at the base of the spinous process. After the entrance point of spinous process screws was determined, posterior C2 spinous process screw implantation was performed bilaterally under direct visualization. On the morphologic CT scan, the width of C2 spinous process base, the angle and length of the spinous process screw trajectory, and the distance between the tip of the screw and the spinal cord and the vertebral artery were measured. RESULTS: The average height and width of the C2 spinous process were (12.90 ± 1.30) mm and (18.86 ± 1.17) mm respectively. The C2 spinous process screws were successfully placed without impingement the spinal cord or the vertebral artery and the breakage of the spinous process. On the CT scan, the average width of the base of C2 spinous process was (20.7 ± 1.3) mm. The placed angles of the screws were 1.8° ± 1.0° in the axial plane. The distance between the tip of the screw and the spinal cord or the vertebral artery was (8.3 ± 2.6) mm and (20.2 ± 3.1) mm respectively. There were little differences between superior and inferior screws in the angle, the distance between the tip of the screw and the spinal cord or the vertebral artery, but without significance (P > 0.05). The average trajectory length of the C2 spinous process screws was (19.7 ± 1.1) mm. The average trajectory length of the superior spinous process screws was shorter than that of inferior spinous process screws, with great differences (t = 3.566, P < 0.01). CONCLUSIONS: There is the anatomic feasibility of the C2 spinous process screw fixation which may afford an alternative to standard screw placement for axis fixation. The biomechanical study for the C2 spinous process screw is also necessary.