Correlation between severity of adolescent idiopathic scoliosis and pulmonary artery systolic pressure: a study of 338 patients.

PURPOSE: Study of patients with adolescent idiopathic scoliosis. OBJECTIVE: To examine the correlation between pulmonary arterial pressure and coronal Cobb angle of idiopathic scoliosis. METHODS: A total of 338 patients (82.8 % female) with idiopathic scoliosis (average age 15.6 years; range 14-20 years) were included. Preoperatively, the coronal Cobb angle of curvature and the apex location and direction were determined from radiographic records. Tricuspid regurgitation velocity (TRV) and inferior vena cava diameter were also measured using Doppler echocardiography. Pulmonary arterial systolic pressure (sPAP) was calculated from the TRV according to the modified Bernoulli equation and correlations between sPAP and the features of scoliosis were identified by statistical analysis. RESULTS: Among the 338 patients, there were 305 thoracic curves, 276 (90.5 %) of which were right curves, and 265 thoracolumbar/lumbar curves. sPAP varied from 5.0 to 37.6 mmHg. Pulmonary hypertension could not be excluded in the case of one patient. A mild correlation (Spearman test, correlation coefficient = 0.187, P = 0.001) between sPAP and coronal Cobb angle of the main thoracic (MT) curves was identified. Correlations between sPAP and the degree of other curves were not significant. Patients with sPAP >20 mmHg also had larger thoracic curve angles (mean MT 42.16° vs. 52.45°; U test, P = 0.002). There were no differences in sPAP levels between patients with right and left thoracic curves. CONCLUSIONS: A mild positive correlation was identified between sPAP and the coronal Cobb angle of the MT curves. There was no relationship between sPAP and the direction of the curvature.

The effect of growing Rod treatment on coronal balance during serial lengthening surgeries in early onset scoliosis.

BACKGROUND: Gaining and maintaining spinal balance after surgery is of great importance for early onset scoliosis (EOS). However, tendency of balance on the coronal plane after growing rod surgery has not been studied before. This study evaluated the effect of growing rod treatment on coronal balance (CB) during serial lengthening surgeries in EOS. METHODS: All EOS patients treated with growing rod technique in our hospital from August 2002 to June 2014 were retrospectively reviewed. Radiographic data before the sixth lengthening surgery were measured on the posteroanterior X-ray images, including global CB (C7 plumbline-central sacral vertical line, C7PL-CSVL), regional CB (apical vertebrae-CSVL), Cobb angle of the main curve and pelvic inlet width (PIW). Global CB index and regional CB index were calculated as dividing global CB and regional CB by PIW, respectively. The changes of these parameters during repeated lengthening surgeries were analyzed. RESULTS: Five hundred seventy Radiographs of 67 patients, including 134 images before and after growing rod insertion surgeries and 436 images pre- and post-lengthening surgeries were measured. Global CB and global CB index did not show significant differences between every two set points during lengthening procedures (P > 0.05). The percentage of patients with C7PL-CSVL distance more than 20 mm roughly ranged from 30 to 45 % during the lengthening process. With regards to regional CB and main curve Cobb angles, there were significant differences between every two adjacent set points during the first five lengthening surgeries (P < 0.05). CONCLUSIONS: Global CB did not significantly change during serial lengthening surgeries and C7PL-CSVL distances of greater than 20 mm comprised of over one third of patients during growing rod treatment. However, worsening regional CB and Cobb angles of the main curve during lengthening intervals were corrected by lengthening manipulation and maintained at a stable level.

Dual growing rod treatment in early onset scoliosis: the effect of repeated lengthening surgeries on thoracic growth and dimensions.

PURPOSE: To investigate changes in thoracic dimensions (TDs) following repeated lengthening surgeries after dual growing rod treatment of early onset scoliosis and thereby its effect on thoracic growth. METHODS: All EOS patients treated with dual growing rod technique in Peking Union Medical College Hospital from June 2004 to June 2014 were retrospectively reviewed. Thoracic spine height (T1-T12), total spine height (T1-S1), maximal coronal chest width and pelvic inlet width (PIW) were measured on the posteroanterior X-ray images after initial growing rod insertion surgery and after each lengthening surgery. Absolute TDs measurements were normalized by PIW. Changes of absolute and normalized TDs measurements with age and number of lengthening surgeries were analyzed. RESULTS: Radiographs of 229 surgeries of 53 EOS patients were measured, including 49 images after initial growing rod insertion surgery and 180 images of lengthening surgeries. Significant positive correlations between age and all three absolute TDs were found (P < 0.01) whereas significant negative correlations between age and all three normalized TDs (P < 0.01) were identified. Similarly, negative correlations were also identified between number of lengthening surgeries and the three normalized TDs (P < 0.01). Significant differences of normalized TDs were identified between initial surgery and the first lengthening through covariance analysis (P < 0.01). Yet, such differences were seldom seen between every two adjacent lengthening surgeries. CONCLUSIONS: Growing rod technique could maintain TDs growth through repeated lengthening procedures but the growth rate was compromised as the number of lengthening procedures increased.

[Features of pelvic parameters in adolescent idiopathic scoliosis and their relationships with spinal sagittal parameters].

OBJECTIVE: To explore the features of pelvic parameters in patients with adolescent idiopathic scoliosis (AIS) and the relationships with spinal sagittal parameters and evaluate their roles in sagittal balance. METHODS: A total of 112 AIS patients from March 2007 to February 2011 were recruited. Six parameters were evaluated from lateral standing radiographs:pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), lumbar lordosis (LL), thoracic kyphosis (TK) and sagittal vertical axis (SVA). Pearson's correlation was used to determine the relationship between the above parameters and t-test applied to compare the differences between the subgroups: (1) by the major curve types in coronal plane (primary thoracic curve vs. primary lumbar curve); (2) by the value of SVA (positive vs. negative). RESULTS: The values of PI and SS in our cohort were 47.2° and 39.4° and they were lower than those in Caucasians as previously reported. PI was correlated with SS, PT and LL (r = 0.562, 0.773 and 0.278 respectively); TK not correlated with pelvic parameters (PI, PT and SS). SVA correlated with both spinal (TK, LL) and pelvic parameters (PI, PT). In the subgroup analyses, the values of PI and SS were significantly higher in the primary thoracic curve subgroup than those in the primary lumbar curve subgroup (49.4° vs 45.1°, 41.0° vs 38.0°). The values of PI and PT were distinctively higher in the positive SVA subgroup than those in the negative SVA subgroup (54.6° vs 45.6°, 14.3° vs 6.2°). CONCLUSION: Ethnic differences exist in the main pelvic parameters and their values are lower in Chinese than in Caucasians. There are also differences among different types of AIS. The values of main pelvic parameters are higher in AIS patients with a primary thoracic curve than in those with a primary lumbar curve. Pelvic parameters play an important role in maintaining a sagittal balance. The main pelvic parameters have influences on sagittal lumbar configuration but little on thoracic segment. A high PI value leads to a forward lean in torso with an increased PT as a result of compensation and vice versa. The alteration of PT is a major compensatory pattern of pelvis. The features of pelvic parameters should be considered during surgical planning.

[Analysis of clinical results and complications of growing rod technique for congenital scoliosis].

OBJECTIVE: To evaluate clinical outcomes of growing rod technique in treating young children with congenital scoliosis. METHODS: From August 2002 to October 2009, 34 patients with congenital scoliosis underwent growing rod procedures including 12 male and 22 female patients. Four patients underwent posterior correction surgeries with single growing rod (single growing rod group), 30 patients underwent posterior correction surgeries with dual growing rod(dual growing rod group). The average age at initial surgery was 6.9(2-13) years. Five patients with severe rigid deformity or kyphosis had an osteotomy at apex vertebra with short segmental fusion followed by dual growing rod technique. The analysis included age at initial surgery and final fusion (if applicable), number and frequency of lengthenings, and complications. Radiographic evaluation including scoliosis, trunk translation, length of T1-S1, thoracic kyphosis and lumbar lordosis was conducted. RESULTS: The follow-up was 40.5 (24-110) months. In single growing rod group, the mean scoliosis Cobb angle improved from 80.9°to 59.5°after initial surgery and was 65.3°at the latest follow-up. T1-S1 length increased from average 24.3 cm to 26.0 cm after initial surgery, and to 31.1 cm at latest follow-up with an increase of 1.05 cm per year. The space available for lung ratio(SAL) in patients with thoracic curves improved from 0.81 to 0.92 at the latest follow-up. Three patients reached final fusion. Four complications occurred in 3 of the 4 patients. In dual growing rod group, the mean scoliosis Cobb angle improved from 72° ± 22°to 35 ± 14° after initial surgery and was 35 ± 17°at the last follow-up or post-final fusion. T1-S1 length increased from (25 ± 5) cm to (29 ± 5)cm after initial surgery and to (33 ± 5)cm at latest follow-up with an average T1-S1 length increase of 1.49 cm per year. The SAL in patients with thoracic curves improved from 0.84 ± 0.08 to 0.96 ± 0.06 at the latest follow-up. Three patients reached final fusion. Complications occurred in 7 of the 30 patients, and they had a total of 13 complications. CONCLUSIONS: Growing rod technique is a safe and effective choice for young children of long, complex congenital scoliosis. It maintains correction achieved at initial surgery while allowing spinal growth to continue. Implants-related complications remain the biggest challenge.

[Analysis of ribs and intraspinal anomalies in congenital scoliosis].

OBJECTIVE: To investigate the incidences and characteristics of the ribs and intraspinal abnormalities in surgical patients with congenital scoliosis. METHODS: We conducted a retrospective study of the medical records and spine radiographs of 118 patients underwent surgical treatment between January 2010 and March 2011 with congenital scoliosis. The average age was 14 years (3-50 years).Fifty-two were male and 66 were female patients. The rib and intraspinal abnormalities were compared in different vertebral anomalies. Pearson's χ(2) test were used to analyze the incidence of anomalies of the ribs and vertebrae, as well as intraspinal anomalies. RESULTS: A total of 57 (48.3%) patients were found to have intraspinal abnormalities.Split cord deformities were identified to be the most common intraspinal anomaly (32.2%), followed by syringomyelia (21.2%).Sixty-nine patients (58.5%) had rib anomalies, which occurring on the concavity of the scoliosis was most frequent. The patients with mixed deformity and failure of segment were found to have a higher incidence of rib anomaly than those with failure formation (χ(2) = 14.05, P < 0.01). The patients with multiple level malformations were found to have significantly higher incidence of rib anomaly than those with single level malformation (χ(2) = 27.50, P < 0.01).Intraspinal anomalies occurred in 42 of 69 patients (60.9%) with rib anomalies and 15 of 49 patients (30.6%) without rib anomalies in congenital scoliosis. The occurrence of intraspinal malformation has significant difference with or without rib anomalies in congenital scoliosis (χ(2) = 10.5, P < 0.01). CONCLUSIONS: The intraspinal malformation is common in patients with mixed defects and failures of segmentation. The rib anomalies occurring on the concavity of the scoliosis is most frequent. The incidence of intraspinal anomaly is significant higher in the patients with rib anomalies than those without rib anomalies. Both the occurrence and type of rib anomaly, combined with vertebral deformity are helpful in forecasting the occurrence of intraspinal abnormalis.

Surgical treatment of atlantoaxial dysplasia and scoliosis in spondyloepiphyseal dysplasia congenita: A case report.

BACKGROUND: Spondyloepiphyseal dysplasia congenita (SEDC) is a rare autosomal dominant hereditary disease caused by COL2A1 mutations. SEDC primarily involves the skeletal system, with typical clinical manifestations, including short stature, hip dysplasia, and spinal deformity. Due to the low incidence of SEDC, there are only a few case reports regarding the surgical treatment of SEDC complicated with spinal deformities. CASE SUMMARY: We report a case of a 16-year-old male patient with SEDC. He presented with typical short stature, atlantoaxial dysplasia, scoliosis, and hip dysplasia. Cervical magnetic resonance imaging showed spinal canal stenosis at the atlas level and cervical spinal cord compression with myelopathy. The scoliosis was a right thoracic curve with a Cobb angle of 65°. He underwent atlantoaxial reduction, decompression, and internal fixation from C1-C2 to relieve cervical myelopathy. Three months after cervical surgery, posterior correction surgery for scoliosis was performed from T3 to L4. Scoliosis was corrected from 66° to 8° and remained stable at 2-year follow-up. CONCLUSION: This is the first case report of a patient with SEDC who successfully underwent surgery for atlantoaxial dysplasia and scoliosis. The study provides an important reference for the surgical treatment of SEDC complicated with spinal deformities.

[Surgical treatment of scoliosis associated with syringomyelia].

OBJECTIVE: To explore the clinical manifestations and surgical strategies of scoliosis associated with syringomyelia. METHODS: A total of 50 cases diagnosed as scoliosis with syringomyelia between January 2003 and November 2010 were recruited. They were divided into 2 groups: Group A, neurosurgery before scoliosis correction, including suboccipital decompression and syrinx shunting; Group B, one-staged posterior correction and instrumentation without previous neurosurgery. The preoperative, postoperative and last follow-ups of Cobb angle of coronal main curve and thoracic kyphosis were measured. Also the preoperative and postoperative apical vertebra translation, apical vertebra rotation and trunk shift were measured by the same person. The surgical efficacies and complications of correction were compared between 2 groups. RESULTS: All patients underwent posterior pedicle screw instrumentation and had a mean follow-up period of 32.1 months. Among them, 42 patients had clinical symptoms or signs preoperatively and 3 patients improved postoperatively. The mean correction of coronal curve was 65.7% and a mean loss of correction 6.4% during the follow-up. The mean correction of apical vertebra translation and apical vertebra rotation were 63.0% and 60.0% respectively. However, the trunk shift increased 0.4 cm. There were no statistically significant differences for the correction efficacies and complications between 2 groups (P > 0.05). CONCLUSION: Scoliosis associated with syringomyelia may be effectively managed if a surgeon manipulates carefully intraoperatively and perioperative spinal monitoring is practiced. Furthermore syrinx will not increase the incidence of postoperative complications without prophylactic neurosurgery.

[The efficacy of one-stage posterior correction surgery for scoliotic patients with little symptomatic syringomyelia].

OBJECTIVE: To investigate the safety and effectiveness of one-stage posterior correction of scoliosis associated with little symptomatic syringomyelia. METHODS: A total of 19 cases diagnosed as scoliosis with little symptomatic syringomyelia between January 2003 and November 2010 were included in this study (study group), the patients underwent one-stage posterior correction and instrumentation without neurosurgery for the syringomyelia. At the same time, 9 cases with severe symptomatic syringomyelia were included as the control group, the patients underwent neurosurgery before scoliosis correction, including suboccipital decompression and syrinx shunting. All patients underwent posterior pedicle screw or screw-hook hybrid instrumentation. The preoperative, postoperative and the last follow-up of the Cobb angle of the coronal main curve and thoracic kyphosis were measured. Also, the preoperative and postoperative of the apical vertebra translation, apical vertebra rotation and trunk shift were measured by the same person. The perioperative and the last follow-up complications of neurological injury were recorded. The surgical outcome and postoperative complications between the 2 groups were compared with the t student and chi-square statistics methods. RESULTS: There were no significant differences in gender, age, the location, length and diameter of the syringomyelia of the 2 groups (P > 0.05). The follow-up period ranged from 6 to 45 months, with a mean of 28.6 months. The average preoperative Cobb angles of coronal main curves of the 2 groups were 71° ± 23° and 68° ± 19°, the postoperative Cobb angles were 27° ± 20° and 25° ± 16°, and the last follow-up Cobb angles were 29° ± 17° and 32° ± 20°. The coronal correction rate was 66% ± 19% in the study group and 65% ± 21% in the control group (t = 0.136, P = 0.893). There was no significant difference at the last follow-up(t = 0.210, P = 0.837). The average preoperative Cobb angles of thoracic kyphosis of the 2 groups were 35° ± 18° and 32° ± 19°, the postoperative Cobb angles were 25° ± 10° and 23° ± 9°, and the last follow-up Cobb angles were 24° ± 4° and 28° ± 8°. The mean sagittal correction rate of the 2 groups were 50% ± 58% and 57% ± 53% (t = -0.303, P = 0.764). There was also no significant difference at the last follow-up time (t = 0.769, P = 0.490). There were no significant difference, in terms of the postoperative of the apical vertebra translation, apical vertebra rotation and trunk shift between the 2 groups (P > 0.05). One case in the study group complicated with a pedicle screw breaking the anterior cortex of the vertebra and one in the control group complicated with a hook loosening, postoperatively. At the last follow-up time, the neurological symptoms of the 2 groups got no aggravating. CONCLUSION: One-stage posterior correction of scoliosis associated with little symptomatic syringomyelia may be effective and safe.

[The surgery treatment of scoliosis associated with tethered cord].

OBJECTIVE: To evaluate the safety and effectiveness of correction of scoliosis associated with tethered cord without releasing it. METHODS: Twenty-two cases diagnosed as scoliosis with tethered cord between December 2005 and January 2011 were investigated retrospectively in the study. There were 8 males and 14 females. The age was from 6 to 51 years, averaged 17.7 years. There were 7 patients with clinical symptoms before surgery. All the patients underwent posterior deformity correction and instrumentation by pedicle screws directly without releasing the tethered cord. Spinal cord monitoring was conducted in all the cases. The preoperative and postoperative Cobb angle of the coronal main curve and thoracic kyphosis were measured. Also, the preoperative and postoperative values of the apical vertebra translation, apical vertebra rotation and trunk shift were measured by the same person. The incidence of perioperative complications were recorded. RESULTS: A total of 20 patients were followed up. The follow-up time was from 6 to 52 months, mean 23.5 months. The average Cobb angle of the coronal main curve were 68° ± 20° before surgery and 38° ± 21° after surgery with a mean correction of 48.1%. The difference was significant (t = 13.9, P < 0.05). The mean kyphosis was 65° ± 18° preoperatively and 28° ± 11° postoperatively, with a correction of 56.7%. The difference was also significant (t = 8.81, P < 0.05). The preoperative values of the apical vertebra translation, apical vertebra rotation and trunk shift were (5.4 ± 2.5) cm, 2.3° ± 0.6° and (2.0 ± 1.8) cm, respectively, which were corrected to (3.2 ± 1.8) cm, 1.2° ± 0.5° and (1.5 ± 1.1) cm after the surgery. Compared to the preoperative values, the difference were significant in the apical vertebra translation (t = 5.69, P < 0.05) and apical vertebra rotation (t = 10.07, P < 0.05). However, there was no difference in trunk shift. Postoperative complications occurred in 3 patients, including transient numbness of the lower extremity in 1 patient and hydrothorax in 2 patients. No neurological and instrumentation complications occurred during the follow-ups. Patients with clinical symptoms before surgery got no serious during the surgery and follow-ups. CONCLUSIONS: If there are no symptoms of tethering in scoliosis patients with tethered cord, the corrective surgeries may be safe and effective when spinal cord monitoring conducted without spinal cord untethering. But more cases are needed to confirm it.

Uncoupled neuro-osseous growth in adolescent idiopathic scoliosis? A preliminary study of 90 adolescents with whole-spine three-dimensional magnetic resonance imaging.

Previous literatures revealed abnormal cross-sectional morphology of spinal cord in AIS, suggesting the presence of disproportional growth between the neural and skeletal system. No accurate measurement of whole spine by MRI multiplanar reconstruction and their correlation with Cobb angle were studied. In this study, MRI three-dimensional reconstruction of the whole spine was performed in 90 adolescents (49 AIS with thoracic/thoracolumbar curve, and 41 age-matched healthy controls). Measurements of the ratio of anteroposterior (AP) and transverse (TS) diameter of the cord, the concave and convex lateral cord space (LCS) were obtained at the apical level in AIS patients. Cerebellar tonsillar level related to the basion-opsithion line, location of conus medullaris, cord length, vertebral column length, cord/vertebral column length ratio were obtained. All of the same parameters were also measured in healthy controls at matched vertebral levels and their correlations with Cobb angle were made. We notice that AP, TS, AP/TS and LCS ratio were increased in AIS subjects with low-lying position of cerebellar tonsillar level and elevating position of conus medullary when compared with healthy controls (P < 0.01). AP, AP/TS and LCS ratio were correlated significantly with Cobb angle (P < 0.05). Cord length and vertebral column length were not significantly different between AIS and control group. However, cord/vertebral column length ratio was significantly smaller in AIS group (P < 0.01). Cord length, vertebral column length and cord/vertebral column length ratio were not related with age or Cobb angle (P > 0.05). These data suggest the presence of uncoupled neuro-osseous growth along the longitudinal axis of spinal cord with associated morphologic changes of cross-sectional configuration and relative position of the cord. Some changes are significantly relevant with Cobb angle, which may indicate pathogenesis of AIS.

[Selective thoracic fusion in the scoliosis associated with syringomyelia].

OBJECTIVE: To evaluate the surgical results of selective thoracic fusion (STF) for scoliosis associated with syringomyelia. METHODS: From January 2001 to January 2009, 93 cases of scoliosis associated with syringomyelia were retrospectively reviewed. There were 11 cases who underwent STF and were followed up more than 2 years, which included 8 female and 3 male, the mean age was 14.9 years (9 - 21 years). Curve type, coronal and sagittal Cobb angle, apical vertebral rotation apical vertebral translation, flexibility, trunk shift were recorded and analyzed. RESULTS: There were 9 double curves and 2 triple curves, the Lenke type of thoracolumbar/lumbar curve included Lenke A in 2 cases, Lenke B in 7 cases and Lenke C in 2 cases. The average coronal Cobb angle of thoracic curve before and after surgery were 62.6° and 19.0° respectively, and the average correction rate was 69.6%. The average coronal Cobb angle of thoracolumbar/lumbar curve before and after surgery were 36.1° and 11.6° respectively, and the average spontaneous correction rate was 67.9%. The followed up time ranged from 24 to 48 months (mean 29.5 months), the average loss of correction rate was 6.8%. Only one trunk decompensation was noted at final follow-up. Pedicle screw nut loosening occurred in one patient and this patient underwent revision surgery, no neurological complication was noted at final follow-up. CONCLUSIONS: STF could be safely performed in scoliosis associated with syringomyelia. Thoracolumbar/lumbar curve in these patients has similar spontaneous correction ability compared with idiopathic scoliosis patients. The satisfactory result could be achieved according to the STF criteria for IS.

[Expression of chondromodulin-1 in the adult degenerative intervertebral disc].

OBJECTIVES: To investigate the expression of chondromodulin-1 (ChM-I) in human adult degenerative intervertebral disc (IVD) cells and the relationship between ChM-I expression and disc degeneration. METHODS: Three degenerated disc specimens obtained from patients in the treatment of disc degenerative disease from March to April 2009 were used for cell culture. ChM-I expression in IVD cells was examined by RT-PCR and Western blot. The effect of basic fibroblast growth factor (bFGF) on the expression of ChM-I was assessed by real-time PCR and Western blot. From October 2008 to October 2009, 26 human IVD tissues were obtained from patients in the surgical treatment of disc degenerative disease at different stage of degeneration according to MRI. Six IVD tissues removed from patients with metastatic spinal tumor were used as normal control. The expression of ChM-I determined by immunohistochemical analysis was correlated with MRI degeneration grade. RESULTS: RT-PCR and Western blot examination showed that ChM-I was expressed in both adult degenerative anulus fibrosus and nucleus pulposus cells. The mRNA and protein expression of ChM-I were both down-regulated by administration of bFGF with dose-dependent way (P < 0.05). Immunohistochemical analysis showed the percent of ChM-I immunopositive cells in the control group was 0.12 ± 0.03, and the number increased significantly in the advanced degeneration group (P < 0.05). CONCLUSIONS: The current results demonstrate that IVD cells express ChM-I. Administration of bFGF down-regulates the expression of ChM-I. The expression of ChM-I is correlated with the degree of IVD degeneration which means it may involve in the process of IVD degeneration.

Postoperative disc wedging in adolescent idiopathic thoracolumbar/lumbar scoliosis: a comparison of anterior and posterior approaches.

OBJECTIVE: To evaluate the different influences of anterior and posterior correction and fusion approaches upon disc wedging in adolescent idiopathic thoracolumbar/lumbar scoliosis. METHODS: The retrospective study was conducted with the medical records and radiographs of adolescent idiopathic thoracolumbar/lumbar scoliosis patients that underwent anterior (group A) or posterior (group B) correction and fusion surgery from December 1998 to May 2008. The correction of the main curve and changes of the disc wedging were analyzed. RESULTS: Fifty-three patients were included, 26 in group A and 27 in group B. The mean coronal Cobb angles of the main curve in group A and group B were significantly corrected after surgery (P < 0.05), with an average correction rate of 75.2% and 88.2%, respectively. Upon final follow-up, the coronal Cobb angles of the two groups were 18.90 +/- 11.1 degrees and 7.70 +/- 5.6 degrees, respectively, with an average correction loss of 6.8 degrees +/- 6.5 degrees and 2.7 degrees +/- 3.3 degrees, respectively. The coronal Cobb angle after operation and at final follow-up, and the correction rate were significantly better in group B than those in group A (P < 0.05), while the coronal Cobb angle loss in group A was greater than that in group B (P < 0.05). The disc wedging before operation, after operation, and at final follow-up were 3.2 degrees +/- 3.0 degrees, 5.7 degrees +/- 3.0 degrees, and 8.6 degrees +/- 4.4 degrees in group A, and 2.4 degrees +/- 3.2 degrees, 3.3 degrees +/- 3.4 degrees, and 3.7 degrees +/- 3.6 degrees in group B, respectively. Postoperative disc wedging was significantly larger compared with preoperative measurements in group A (P < 0.05), but not in group B (P > 0.05). The difference between disc wedging at final follow-up and that after surgery was significant in group A (P < 0.05), but not in group B (P > 0.05). Between the two groups, group A had larger disc angles after operation and at final follow-up (P < 0.05), and a greater loss of disc angle (P < 0.05). CONCLUSION: For adolescent idiopathic thoracolumbar/lumbar scoliosis, posterior approach using all pedicle screws might produce a better result in terms of disc wedging compared with anterior approach.

[Selection of distal fusion levels in the surgical management of thoracolumbar/lumbar adolescent idiopathic scoliosis].

OBJECTIVE: To investigate the efficacy and safety of a new method which determines the exact distal fusion level in the treatment of adolescent idiopathic scoliosis (AIS) with posterior pedicle screw fixation and to assess its clinical outcome. METHODS: This prospective clinical study analyzed 31 AIS patients who met the inclusion criteria enrolled from July 2005 to September 2008. Based on the principle of our new criteria for selection of distal fusion level of AIS, all patients had posterior spinal fusion and instrumentation with pedicle screws. Cobb angle of the curve, tilt angle of the LIV, intervertebral angle and trunk shift were measured and analyzed. RESULTS: Preoperative (42 + or - 17) degrees of thoracic curve was corrected to (12 + or - 7) degrees , with a curve correction of 70.6%. Preoperative (44 + or - 7) degrees of lumbar curve was corrected to (9 + or - 4) degrees , with a curve correction of 80.2%. The trunk shift were significantly improved from (13 + or - 8) mm to (9 + or - 7) mm before and after surgery respectively (P < 0.05). The tilt angles of the LIV before and after surgery were (20.8 + or - 5.7) degrees and (1.5 + or - 3.1) degrees respectively. The thoracic Cobb angle was (14 + or - 8) degrees and the lumbar Cobb angle was (9 + or - 5) degrees at latest follow up. The changes were of significance in the tilt angle of the LIV after surgery compared with that before surgery (P = 0.000). This angle averaged (0.8 + or - 3.7) degrees at final follow up, but the change was not significant compared with that after surgery (P > 0.05). CONCLUSION: This is an effective method with the advantage of shortening the fusion level, reserving the distal motion segments and easing segmental degeneration adjacent to the fusion area.

[A meta-analysis of the effectiveness and safety of using tranexamic acid in spine surgery].

OBJECTIVE: To assess the effectiveness and safety of using tranexamic acid (TXA) in reducing blood loss in spine surgery through a meta-analysis. METHODS: Literatures before November 2009 were identified from the PubMed, EMBase, Cochrane library, CNKI and VIP databases. Relevant journals or conference proceedings were also searched manually. This study only enrolled high quality (Jadad scores ≥ 3) randomized controlled trials (RCTs). Two independent reviewers searched and assessed the literatures.Weighted mean difference (WMD) of blood loss and blood transfusions, odds ratio (OR) of transfusion rate and of deep vein thrombosis (DVT) rate in TXA-treated group versus placebo group were calculated across the studies. The statistical analysis were conducted by the software of RevMan 4.2. RESULTS: Four double-blinded RCTs met the inclusion criteria for meta-analysis. The total sample size of these studies was 295. The use of TXA significantly reduced total blood loss [WMD = -523.74, 95%CI (-778.92, -268.56), P < 0.01], blood volumes of transfusion [WMD = -242.28, 95%CI (-394.02, -90.54), P = 0.002] and proportion of patients requiring blood transfusion [OR = 0.57, 95%CI (0.34, 0.93), P = 0.020], while did not raise the risk of DVT, as compared with placebo group. CONCLUSIONS: This meta-analysis indicates that the use of TXA infusion for patients undergoing spine surgery is effective in reducing total blood loss, transfusion volumes and the rate of transfusion, yet doesn't raise the risk of postoperative DVT.

[Radiological evaluation of intervertebral angles on short-segment fusion of degenerative lumbar scoliosis].

OBJECTIVE: To analyze the radiological change of intervertebral angles after the short-segment fusion of degenerative lumbar scoliosis. METHODS: From January 2001 to May 2007, 28 patients (mean age 62 years old) with degenerative lumbar scoliosis, including 6 male and 22 female, were reviewed retrospectively. The average vertebra number in the lumbar curve were 4.8, ranging from 3 to 6. All the patients underwent posterior decompressive laminotomy, pedicle screw fixation, and posterolateral fusion. The fusion levels were within the curve in all the cases (mean 3.3 vertebrae), without exceeding the end vertebrae. All the patients took standing lumbar antero-posterior and sagittal radiological images pre and post-surgery and upon follow up. The coronal scoliosis Cobb angle, anterior and sagittal intervertebral angles of upper adjacent segment of proximal fused vertebra were measured. The following aspects were also evaluated such as bone graft fusion and complications. RESULTS: Follow up period of 25-97 months, average 50 months; post-operative scoliosis Cobb angle average correction rate was 33.7%, final follow up average correction loss was 3.7 degrees , pre-operative and final follow up results compared with post-operative indicated significant difference (P < 0.05); final follow-up antero-posterior proximal upper fusion segment intervertebral angle compared with pre-operative and postoperative presenting significant difference (P < 0.05). Upon final follow up, all cases did not present pseudo-arthrosis or internal instrumentation related complications. CONCLUSION: For degenerative lumbar scoliosis, short-segment fusion can produce limited correction on antero-posterior proximal upper fusion segment intervertebral angle and cannot stop its aggravation.

Posterior selective thoracic fusion in adolescent idiopathic scoliosis patients: a comparison of all pedicle screws versus hybrid instrumentation.

OBJECTIVE: To analyze the influence of segmental pedicle screws versus hybrid instrumentation on the correction results in adolescent idiopathic scoliosis patients undergoing posterior selective thoracic fusion, METHODS: By reviewing the medical records and roentgenograms of adolescent idiopathic scoliosis patients who underwent selective thoracic fusion from February 2000 to January 2007 in our hospital, the patients were divided into 2 groups according to different instrumentation fashions: Group A was hook-screw-rod (hybrid) internal fixation type, Group B was screw-rod (all pedicle screws) internal fixation type, and the screws were used in every segment on the concave side of the thoracic curve. The parameters of the scoliosis were measured and the correction results were analyzed, RESULTS: Totally, 48 patients (7 males, 41 females) were included, with an average age of 14.4 years old and a mean follow-up time of 12.3 months. Thirty and 18 patients were assigned to group A and group B, respectively. The mean preoperative coronal Cobb angles of the thoracic curve were 48.8 degrees and 47.4 degrees, respectively. After surgery, they were corrected to 13.7 degrees and 6.8 degrees, respectively. At final follow-up, they were 17.0 degrees and 9.5 degrees, with an average correction rate of 64.6% and 79.0%, respectively, and the correction rate of group B was significantly higher than that of group A (P = 0.003). The mean preoperative coronal Cobb angles of the lumbar curve were 32.6 degrees and 35.2 degrees, respectively. After surgery, they were corrected to 8.6 degrees and 8.3 degrees, respectively. At final follow-up, they were 10.3 degrees and 11.1 degrees, with an average correction rate of 66.8% and 69.9%, respectively, and the correction rate of group B was significantly higher than that of group A (P = 0.003). The correction loss of the thoracic curve and lumbar curve in the 2 groups were 3.1 degrees and 1.8 degrees, 2.4 degrees and 2.4 degrees, respectively. No significant difference was noted (both P > 0.05). The decompensation rate at final follow-up in these 2 groups were 4% (1/25) and 7.1% (1/14) respectively, with no significant difference (P > 0.05). CONCLUSIONS: Both all pedicle screws and hybrid instrumentation can offer good correction results of the thoracic curve and lumbar curve in posterior selective thoracic fusion in patients with adolescent idiopathic scoliosis. While with all pedicle screws, the correction results of the thoracic curve and lumbar curve are both better than those with hybrid instrumentation without increased decompensation rate.

[Comparison of correction outcomes after anterior or posterior approach with lowest and vertebra instrumentation in adolescent idiopathic thoracolumbar/lumbar scoliosis].

OBJECTIVE: To evaluate the different influences upon the correction outcomes after anterior or posterior correction and fusion with lowest end vertebra instrumentation in adolescent idiopathic thoracolumbar/lumbar scoliosis. METHODS: By reviewing the medical records and roentgenograms of adolescent idiopathic thoracolumbar/lumbar scoliosis patients undergoing anterior (single rod-Group A) or posterior (all pedicle screws-Group B) correction and instrumentation, the parameters of Cobb angle of the curve, correction rate and disc angle were measured and analyzed. RESULTS: There were 18 patients in Group A and 21 patients in Group B. The curve included 5.0 vertebrae and 5.5 vertebrae (P = 0.134) respectively, and the fusion levels were 4.7 vertebrae and 5.4 vertebrae (P = 0.008) respectively. The mean pre-operative and post-operative coronal Cobb angles of the main curve in Groups A and B were 49.2 degrees and 10.3 degrees , 42.2 degrees and 5.0 degrees with an average correction rate of 78.5% and 87.8% respectively. The Cobb angles were all significantly corrected (all P = 0.000), and group B had a better correction result (P = 0.020). At final follow-up, the coronal Cobb angles in the two groups were 21.7 degrees and 7.7 degrees with an average correction loss of 8.3 degrees and 2.7 degrees (P = 0.001) respectively. The disc angles at pre-operation, post-operation and final follow-up were 3.1 degrees , 5.6 degrees and 7.3 degrees in Group A and 2.3 degrees , 4.2 degrees and 4.4 degrees in Group B respectively. The disc angle at post-operation was larger than that at pre-operation and the difference was significant in Group A (P = 0.049) while not in Group B (P = 0.050). The difference of post-operative disc angle between two groups was not significant (P = 0.231). At final follow-up, the disc angle was a little larger than that of post-operation without a significant difference (P = 0.112, P = 0.855) while Group A had a larger disc angle (P = 0.026). At final follow-up, the occurrence of proximal junctional kyphosis between Groups A and B was not significant (P = 0.235). CONCLUSION: For adolescent idiopathic thoracolumbar/lumbar scoliosis, in comparison with the anterior approach, the posterior approach using all pedicle screws can achieve a better correction outcome, a less correction loss of coronal Cobb angle and a better disc angle with a longer fusion range.

[Finite element analysis of stress changes of posterior spinal pedicle screw infixation].

OBJECTIVE: To evaluate the mechanical response of L3-L4 segment after posterior interfixation with a transpedicle screw system. METHODS: Spiral CT machine was used to conduct continuous parallel scan on the L3-L4 section of a 40-year-old healthy male Chinese. The image data thus obtained were introduced into MIMICS software to reconstruct the 2-D data into volume data and obtain 3-D models of every element.. Pro/3-D model construction software system was used to simulate the 3-D entity of L3-L4 fixed by screw robs through spinal pedicle via posterior approach that was introduced into the finite element software ABAQUS to construct a 3-D finite element model. The stress changes on the vertebrae and screw under the axial pressure of 0.5 mPa was analyzed. RESULTS: Under the evenly distributed pressure the displacement of the L4 model was 0.00125815 mm, with an error of only 0.8167% from the datum displacement. The convergence of the model was good. The stress of the fixed vertebral body, intervertebral disc, and internal fixators changed significantly. The stress concentration zone of the intervertebral disc turned from the posterolateral side to anterolateral side. The stress produced by the fixed vertebral bodies decreased significantly. Obvious stress concentration existed in the upper and lower sides of the base of screw and the fixed screw at the upper vertebral body bore greater stress than the lower vertebral body. CONCLUSIONS: Integration of computer aided device and finite element analysis can successfully stimulate the internal fixation of L3-IA visa posterior approach and observe the mechanic changes in the vertebral column more directly.