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find Keyword "curvature" 9 results
  • CLINICAL SIGNIFICANCE OF POSTERIOR INTERNAL FIXATION FOR REGULATION OF SPINAL CURVATURE IN THORACOLUMBAR COMPRESSION FRACTURES

    Objective To investigate the clinical significance of applicating posterior internal fixation for regulating spinal curvature in thoracolumbar compression fractures. Methods Between May 2006 and May 2009, 63 patients with thoracolumbar compression fractures were treated, and the clinical data were retrospectively analyzed. Among them, 33 patients received traditional posterior internal fixation in control group; 30 patients underwent posterior internal fixation with spinal curvature correction under C-arm X-ray device in trial group. There was no significant difference in age, gender, cause of injury, injured segment, grade of fracture, and time from injury to operation between 2 groups (P gt; 0.05). The Cobb angle, height of injured vertebral body, and disc height were measured by X-ray examination; loosening and breakage of internal fixation were observed and compared between 2 groups. The recovery rate was calculated according to pre- and post-operative visual analogue scale (VAS) and Oswestry disability index (ODI) scores for each patient. Results All cases were followed up 20-45 months (mean, 31 months). The postoperative VAS score, ODI, Cobb angle, height of injured vertebral body, and disc height were improved significantly when compared with preoperative values in 2 groups (P lt; 0.05). At last follow-up, VAS and ODI scores of trial group were significantly better than those of control group (P lt; 0.05); loss of Cobb angle was (2.1 ± 1.7)° in trial group and (4.2 ± 3.2)° in control group, showing significant difference (t=1.457, P=0.000); loss of disc height was (1.4 ± 1.2) mm in trial group and (3.4 ± 2.3) mm in control group, showing significant difference (t=9.336, P= 0.000); loss of height of injured vertebral body was 1.8% ± 0.6% in trial group and 5.4% ± 2.1% in control group, showing significant difference (t=3.435, P=0.000). Broken screw and loosening screw occurred in 1 case of control group, respectively (6.1%), but no broken or loosening screw in trial group, showing significant difference (P=0.000). Conclusion Application of posterior internal fixation for regulating spinal curvature has a good clinical effectiveness. The postoperative spinal curvature, the height of injured vertebral body, and disc height can be improved significantly and low back pain can be recovered satisfactorily. The modified technique is also effective in reducing broken and loosening incidence of the fixation system.

    Release date:2016-08-31 04:06 Export PDF Favorites Scan
  • LONG-TERM EFFECT OF EXCESSIVE LENGTH OF BONE GRAFT VIA ANTERIOR CERVICAL APPROACH ON CERVICAL CURVATURE AND AXIAL SYMPTOM

    Objective To evaluate the long-term effect of excessive length of bone graft via anterior cervical approach and over distraction of intervertebral space on cervical curvature and postoperative neck axial symptom (AS). Methods FromJune 2001 to June 2004, 30 patients with nerve root cervical spondylosis at the C5,6 level underwent anterior cervicaldecompression, autogenous il iac bone graft and internal fixation with titanium plate. There were 14 males and 16 females aged 32-73 years old (average 54.7 years old), and the course of disease was 1-31 months (average 7 months). No instabil ity of cervical vertebrae was noted on the cervical dynamic position x-ray films. Intervertebral height was measured immediately after operation, and accordingly the patients were divided into two groups: the over distraction group (n=11), in which the length of bone graft was excessive, the intervertebral space was over distracted, and the intervertebral height was increased by more than 3 mm compared with the preoperative value; the proper distraction group (n=19), in which the length of bone graft was proper, no over distraction of the intervertebral space occured, and the intervertebral height was increased by less than 3 mm compared with the preoperative value. Regular X-ray exams were performed 1 week and 3, 24, and 48 months after operation to analyze bone fusion condition of the grafted bone, changes of the intervertebral height of the fused segments, and variation of physiological curvature of the cervical vertebra. The postoperative neck AS was evaluated according to the the neck AS evaluation criteria set by ZENG Yan and co-workers. Results All patients were followed up for 48-66 months (average 54.5 months). Cl inical symptoms were el iminated in all cases. No compl ications occurred in the proper distraction group; 1 patient of the over distraction group had ostoperative nerve root paralysis at C5 level, and recovered 3 months after proactive treatment. Bone fusion was achieved in all patients 3-6 months after operation, except for 1 case in the proper distraction group suffering from non-fusion 12 months after operation. There was no occurrence of loosening or breakage of steel plate and screw, and no displacement of the grafted bone. At 48 months after operation, the intervertebral height of the proper distraction group and the over distraction group was increased by (1.9 ± 1.8) mm and (3.5 ± 2.7) mm, respectively, when compared with the preoperativevalue (P gt; 0.05). The physiological curvature of the operated cervical segment was well maintained. The curvature of the proper distraction group and the over distraction group at the final follow-up visit was increased by (2.17 ± 1.83)° and (3.32 ± 2.71)°, respectively, when compared with the preoperative value (P gt; 0.05). The physiological curvature of the whole cervical vertebra at the final follow-up visit was increased by (4.57 ± 3.71)° in the proper distraction group and decreased by (2.43 ± 2.13)° in the over distraction group, when compared with the preoperative value (P lt; 0.05). The incidence rate of postoperative neck S at 48 months after operation was 15.79% in the proper distraction group (11 cases excellent, 5 cases good, 3 cases fair) and 54.55% in the over distraction group (3 cases excellent, 2 cases good, 5 cases fair, 1 case poor), showing a significant difference between two groups (P lt; 0.05). Conclusion Excessive length of bone graft via anterior cervical approach and over distraction of intervertebral space are bad for maintaining the physiological curvature of the whole cervical vertebra, and increase the incidence of postoperative neck AS. Selection of bone graft at the proper height is essential in anterior cervical operation.

    Release date:2016-09-01 09:07 Export PDF Favorites Scan
  • EFFECT OF MODIFIED UNILATERALLY-OPEN EXPANSIVE LAMINOPLASTY USING BRIDGE GRAFTING AND RESTRUCTING POSTERIOR LIGAMENTOUS COMPLEX METHODS ON AXIAL SYMPTOMS AND CERVICAL CURVATURE CHANGE

    Objective To explore if the modified unilaterally-open expansive laminoplasty using bridge grafting and reconstructing posterior ligamentous complex methods is effective in preventing persisting axial symptoms, restriction of neck motion, and loss of cervical curvature. Methods From June 2000 to October 2005, 138 patients with cervical spondylotic myelopathy underwent this procedure. Of them, 78 who were followed for more than 2 years (group A) were included in this study. Another 69 patients who underwent conventional unilaterally opendoor laminoplasty served as controls(groupB). The JOA scores and the incidence of newly developed or deteriorated axial symptoms were recorded. Preoperative and postoperative ranges of neck motion were measured on lateral flexion and extension radiographs. Preoperative and postoperative cervical curvature indices were calculated according to Ishihara’s method. Results The patients of group A were followed 24-44 months (mean 33 months), and the patients of group B were followed 2453 months(mean 35 months). The operative time was 114±20 min in group A and 70±25 min in group B,showing statistically significant difference(P<0.05). The operative blood loss was 280±72 ml in group A and 210±80 ml in group B(P>0.05). Accordingto JOA scoring, the average recovery rates were 67.0%±17.3% in group A and 65.0%±21.4% in group B(P>0.05). Postoperative development or deterioration of axial symptoms occurred in 12% of patients in group A and 51% of patients in group B, showing statistically significant difference(P<0.05). Postoperative range of neck motion was 88.0%±10.1% of the preoperative one in group A and 64.0%±16.3% in group B(P<0.05). There was no significant difference between preoperative(15.3±8.2) and postoperative(13.5±9.3) cervical curvature index in group A, whereas the mean value of postoperative index (11.1±5.7) was significantly smaller than that of preoperative one (17.2±13.5) in group B (Plt;0.05). Conclusion This new procedure was less invasive to the posterior extensor mechanism than the conventional unilaterally-open laminoplasty and was effective in preventing postoperative morbidities.

    Release date:2016-09-01 09:22 Export PDF Favorites Scan
  • Biomechanical Analysis of Different ProDisc-C Arthroplasty Design Parameters after Implanted: a Numerical Sensitivity Study Based on Finite Element Method

    This study was aimed to estimate the effect of different ProDisc-C arthroplasty designs after it was implanted to C5-C6 cervicalspine. Finite element (FE) model of intact C5-C6 segments including the vertebrae and disc was developed and validated. Ball-and-socket artificial disc prosthesis model (ProDisc-C, Synthes) was implanted into the validated FE model and the curvature of the ProDisc-C prosthesis was varied. All models were loaded with compressed force 74 N and the pure moment of 1.8 Nm along flexion-extension and bilateral bending and axial torsion separately. The results indicated that the variation in the curvature of ball and socket configuration would influence the range of motion in flexion/extension, while there were not apparently differences under other conditions of loads. The method increasing the curvature will solve the stress concentration of the polyethylene, but it will also bring adverse outcomes, such as facet joint force increasing and ligament tension increasing. Therefore, the design of artificial discs should be considered comprehensively to reserve the range of motion as well as to avoid the adverse problems, so as not to affect the long-term clinical results.

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  • CLINICAL OBSERVATION OF POSTERIOR CERVICAL DECOMPRESSIVE LAMINECTOMY AND LATERAL MASS SCREW FIXATION COMBINED WITH FORAMINOTOMY FOR CERVICAL RADICULO-MYELOPATHY

    ObjectiveTo evaluate the effectiveness of posterior cervical decompressive laminectomy and lateral mass screw fixation combined with foraminotomy for treating cervical radiculo-myelopathy. MethodsBetween January 2010 and January 2012, 58 patients with cervical radiculo-myelopathy were treated by posterior cervical decompressive laminectomy and lateral mass screw fixation combined with foraminotomy. There were 31 males and 27 females, with an average age of 52.7 years (range, 41-72 years). The mean disease course was 5.4 years (range, 3-15 years). The preoperative Japanese Orthopaedic Association (JOA) score was 7.8±1.3, and visual analogue scale (VAS) score was 6.8±1.7. There were 37 cases of inter-vertebral disc herniation and ligamentum flavum hypertrophy, 11 cases of vertebral osteophyte formation with the osteophyte spinal canal occupational ratio of 51.7%±18.1%, and 10 cases of inter-vertebral disc herination with cervical instability. Preoperative cervical curvature was (-5.5±12.5)°. The fixed segments included C3-7 in 29 cases, C4-7 in 19 cases, and C3-6 in 10 cases. Foraminotomy was performed in 135 nerve foramina (mean, 2.33 foramina). ResultsThe mean operation time was 204 minutes (range, 167-260 minutes), and the mean blood loss was 273 mL (range, 210-378 mL). No injury of vertebral artery or nerve root occurred during operation. Postoperative subcutaneous hematoma and cervical axial pain occurred in 1 case and 8 cases, respectively; and no nerve root palsy was observed. The patients were followed up 2.1-4.3 years (mean, 3.4 years). The postoperative JOA score was significantly increased to 14.1±1.7 (t=-27.672, P=0.000), with an improvement rate of 68.5%±21.9%. Postoperative VAS score was significantly decreased to 2.1±1.1 (t=15.168, P=0.000). The imaging examination showed adjacent segmental degeneration in 1 patient, who had no clinical symptom. There was no screw loosening or pseudoarthrosis formation during follow-up. The cervical curvature was (13.6±5.1)° at 5 days and was (13.2±4.8)° at 2 years, showing significant difference when compared with preoperative one (P < 0.05). The osteophyte spinal canal occupational ratio was 36.5%±10.4% at 2 years, showing significant difference when compared with preoperative one (t=6.921, P=0.000). ConclusionThe procedure of posterior cervical decompressive laminectomy and lateral mass screw fixation combined with foraminotomy is effect in treating cervical radiculo-myelopathy. The spinal cord and nerve root can be adequately decompressed by laminectomy and foraminotomy. The lateral mass screw fixation can correct the cervical curvature and further reduce the tension to spinal cord.

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  • Correlation analysis of preoperative T1 slope in MRI and physiological curvature loss after expansive open-door laminoplasty

    Objective To investigate whether preoperative T1 slope (T1S) in MRI can predict the changes of cervical curvature after expansive open-door laminoplasty (EOLP) in patients with cervical spondylotic myelopathy, so as to make up for the shortcomings of difficult measurement in X-ray film. Methods The clinical data of 36 patients with cervical spondylotic myelopathy who underwent EOLP were retrospectively analysed. There were 21 males and 15 females with an average age of 55.8 years (range, 37-73 years) and an average follow-up time of 14.3 months (range, 12-24 months). The preoperative X-ray films at dynamic position, CT, and MRI of cervical spine before operation, and the anteroposterior and lateral X-ray films at last follow-up were taken out to measure the following sagittal parameters. The parameters included C2-C7 Cobb angle and C2-C7 sagittal vertical axis (C2-C7 SVA) in all patients before operation and at last follow-up; preoperative T1S were measured in MRI, and the patients were divided into larger T1S group (T1S>19°, group A) and small T1S group (T1S≤19°, group B) according to the median of T1S, and the preoperative T1S, C2-C7 Cobb angle, C2-C7 SVA, and the C2-C7 Cobb angle and C2-C7 SVA at last follow-up, difference in axial distance (the difference of C2-C7 SVA before and after operation), postoperative curvature loss (the difference of C2-C7 Cobb angle before and after operation), the number of patients whose curvature loss was more than 5° after operation, and the number of patients whose kyphosis changed (C2-C7 Cobb angle was less than 0° after operation). Results The C2-C7 Cobb angle at last follow-up was significantly decreased when compared with preoperative value (t=8.000, P=0.000), but there was no significant difference in C2-C7 SVA between pre- and post-operation (t=–1.842, P=0.074). The preoperative T1S was (19.69±3.39)°; there were 17 cases in group A and 19 cases in group B with no significant difference in gender and age between 2 groups (P>0.05). The preoperative C2-C7 Cobb angle in group B was significantly lower than that in group A (t=–2.150, P=0.039), while there was no significant difference in preoperative C2-C7 SVA between 2 groups (t=0.206, P=0.838). At last follow-up, except for the curvature loss after operation in group B was significantly lower than that in group A (t=–2.723, P=0.010), there was no significant difference in the other indicators between 2 groups (P>0.05). Conclusion Preoperative larger T1S (T1S>19°) in MRI had a larger preoperative lordosis angle, but more postoperative physiological curvature was lost; preoperative T1S in MRI can not predict postoperative curvature loss, but preoperative larger T1S may be more prone to kyphosis.

    Release date:2018-01-09 11:23 Export PDF Favorites Scan
  • Effect of zero-profile and self-locking intervertebral cage and plate-cage construct on maintenance of cervical curvature after anterior cervical surgery

    ObjectiveTo compare differences in the maintenance of cervical curvature after anterior cervical surgery between zero-profile and self-locking intervertebral cage and plate-cage construct (PCC).MethodsA clinical data of 100 patients with single-segment cervical disc herniation who were treated with anterior cervical discectomy and fusion were retrospectively analyzed between January 2015 and January 2016. Among them, 50 patients were treated with the zero-profile and self-locking intervertebral cage (group A) and 50 patients with the PCC (group B). There was no significant difference between the two groups in age, gender, bone mineral density, disease duration, operative segment, and preoperative visual analogue scale (VAS) score, Japanese Orthopaedic Association (JOA) score, C2-7 cervical curvature, segmental Cobb angle, and adjacent vertebral height (P>0.05). The operation time and intraoperative blood loss were recorded. The postoperative VAS and JOA scores were used to evaluate the clinical efficacy. The C2-7 cervical curvature, segmental Cobb angle, and adjacent vertebral height were measured on lateral X-ray films, and the interbody fusion was evaluated according to Pitzen’s criteria.ResultsThe operation time in group A was significantly shorter than that in group B (t=2.442, P=0.021), but there was no significant difference in the intraoperative blood loss between the two groups (t=0.812, P=0.403). All patients were followed up 24-36 months, with an average of 28.5 months. According to Pitzen’s criteria for cervical interbody fusion, bone fusion achieved in both groups. The VAS score, JOA score, C2-7 cervical curvature, segmental Cobb angle, and adjacent vertebral height of the two groups at 1 and 24 months after operation were significantly improved when compared with those before operation (P<0.05). The C2-7 cervical curvature, segmental Cobb angle, and adjacent vertebral height of group A at 24 months changed significantly compared with those at 1 month (P<0.05). The other indexes of the two groups showed no significant difference between the different time points after operation (P>0.05). There were significant differences in C2-7 cervical curvature, segmental Cobb angle, and adjacent vertebral height between the two groups at 24 months after operation (P<0.05); but there was no significant difference in the clinical indexes at 1 and 24 months and the imaging indexes at 1 month between the two groups (P>0.05).ConclusionCompared with the PCC, the zero-profile and self-locking intervertebral cage can significantly shorten the operation time and obtain the same clinical efficacy, but the intervertebral height loss and secondary cervical curvature change after operation is more serious.

    Release date:2020-02-20 05:18 Export PDF Favorites Scan
  • Relationship between O-EA angle and lower cervical curvature in patients with anterior atlantoaxial dislocation before and after occipitocervical fusion

    ObjectiveTo investigate the relationship between O-EA angle and lower cervical curvature in patients with anterior atlantoaxial dislocation undergoing occipitocervical fusion, and to analyze the effect of O-EA angle on lower cervical curvature.MethodsThe clinical data of 61 patients with anterior atlantoaxial dislocation undergoing occipitocervical fusion who were admitted between April 2010 and July 2018 and met the selection criteria were retrospectively analyzed. There were 32 males and 29 females, with an age of 14-76 years (mean, 50.7 years). The fixed segment included 19 cases of C0-C2, 27 cases of C0-C3, 14 cases of C0-C4, and 1 case of C0-C5. The O-EA angle, C2-7 Cobb angle, and T1 tilt angle were measured before operation and at last follow-up. According to the O-EA angle measured at last follow-up, the patients were divided into <95° group (group A), 95°-105° group (group B), and >105° group (group C), and compared the differences of gender, age, fixed segment (short segment was at C3 and above, long segment was beyond C3), and C2-7 Cobb angle. Correlation analysis between the O-EA angle and C2-7 Cobb angle before operation and at last follow-up, as well as the changes of O-EA angle and C2-7 Cobb angle between before operation and at last follow-up were analyzed.ResultsAll 61 patients were followed up 12-24 months, with an average of 22.4 months. There was no significant difference in O-EA angle, C2-7 Cobb angle, and T1 tilt angle before operation and at last follow-up (P>0.05). According to the last follow-up O-EA angle grouping, there were 14 cases in group A, 29 cases in group B, and 18 cases in group C. There was no significant difference in age, gender composition, and fixed segment composition among the three groups (P>0.05); the differences in C2-7 Cobb angles among the three groups were significant (P<0.05), groups A, B, and C showed a gradually increasing trend. The O-EA angle was positively correlated with C2-7 Cobb angle before operation and at last follow-up (r=0.572, P=0.000; r=0.618, P=0.000); O-EA angle change at last follow-up was also positively correlated with C2-7 Cobb change (r=0.446, P=0.000).ConclusionThe O-EA angle of patients with anterior atlantoaxial dislocation is positively correlated with C2-7 Cobb angle. Too large O-EA angle should be avoided during occipitocervical fixation, otherwise it may accelerate the degeneration of the lower cervical spine.

    Release date:2021-04-27 09:12 Export PDF Favorites Scan
  • Comparison and significance of scleral cribriform curvature in different types of glaucoma

    ObjectiveTo observe the differences in scleral lamina curvature (SLC) of patients with pseudoexfoliation glaucoma (PXG), primary open-angle glaucoma (POAG), and primary chronic angle-closure glaucoma (CPACG) were compared and analyzed and their significance was analyzed.MethodsA retrospective clinical study. From June 2017 to December 2020, 30 PXG (PXG group), POAG (POAG group) and CPACG patients (CPACG group) diagnosed at Eye Center of Cangnan County people's Hospital of Zhejiang Province (Cangnan Hospital Affiliated to Wenzhou Medical University) were included in the study. The age difference between the three groups of patients was statistically significant (t=17.925, P=0.001); gender composition ratio (χ2=2.158, P=0.276), intraocular pressure (t=4.993, P=0.078), and axial length (t=1.956, P=0.532), central corneal thickness (t=1.407, P=0.724), average visual field defect (t=2.725, P=0.496), optic disc retinal nerve fiber layer thickness (t=2.185, P=0.492) in comparison, the differences were not statistically significant (P>0.05). The frequency-domain optical coherence tomography deep-enhanced imaging (OCT EDI) technology was used to measure the average and 0°, 30°, 60°, 90°, 120°, 150° SLC of the affected eyes, and calculate the SLC index (SLCI) and SL curve depth (SLCD). Quantitative data comparison between groups used independent sample t test. Count data comparison used χ2 test. Univariate and multivariate logistic regression analysis were used for correlation analysis.ResultsThe results of OCT EDI examination showed that the SLC of eyes with PXG and CPACG was significantly steep, while the SLC of eyes with POAG was relatively flat. Except for the angle of 150°, the other 6 angles of SLCI and SLCD in the PXG group and CPACG group were higher than those in the POAG group, and the differences were statistically significant (P<0.05). However, there was no statistically significant difference between PXG group and CPACG group for 7 angles of SLCI and SLCD (P>0.05). Logistic regression analysis showed that the average SLCI [odds ratio (OR)=1.498, 95% confidence interval (CI) 1.137-2.018, P=0.001], age (OR=1.074, 95%CI 1.019-1.143, P=0.016) was significantly correlated with PXG; mean SLCI (OR=1.625, 95%CI 1.192-1.997, P=0.001), intraocular pressure (OR=1.383, 95%CI 1.106-1.993, P=0.012) was significantly correlated with CPACG. POAG group (β=0.143, 95%CI 0.032-0.208, P=0.016), CPACG group (β=0.132, 95%CI 0.079-0.315, P=0.043) intraocular pressure was correlated with mean SLCI; all factors of PXG group were correlated with SLCI without correlation (P>0.05).ConclusionCompared with POAG, the SLC of eyes with PXG and CPACG is steeper and related to disease occurrence.

    Release date:2021-07-21 02:11 Export PDF Favorites Scan
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