Changwei Yang

Analysis of radiographic parameters relevant to the lowest instrumented vertebrae and postoperative coronal balance in Lenke 5C patients.

Study Design. A retrospective radiographic study. Objective. To investigate which preoperative radiographic parameters best correlate with the angulation and translation of the lowest instrumented vertebra (LIV) and global coronal balance after posterior spinal pedicle screw fixation for thoracolumbar/lumbar (TL/L) adolescent idiopathic scoliosis. Summary of Background Data. Lenke 5C patients with a single, structural TL/L curve can be treated by either an anterior or posterior approach. One of the operative goals when treating Lenke 5C patients is to level and center the LIV, thereby achieving a better global coronal balance. To our knowledge, no study has investigated which specific radiographic parameters correlate with these surgical outcomes after posterior pedicle screw fixation. Methods. Twenty-seven patients with TL/L adolescent idiopathic scoliosis were identified in this study, and they underwent posterior fixation and fusion by pedicle screws with a minimum 2-year follow-up. Preoperative and postoperative radiographs were reviewed measuring various radiographic parameters as well as specific measurements related to the LIV. Correlation of these parameters to LIV translation and global and regional coronal balance (C7-central sacral vertical line [CSVL], LIV-CSVL distance) were then evaluated. Results. Four patients demonstrated global coronal imbalance postoperatively by radiographic and clinical evaluation. Regression analysis identified three radiographic parameters that correlated significantly with the postoperative global coronal balance (C7-CSVL): preoperative C7-CSVL (r = 0.44, P = 0.023), preoperative LIV tilt (r = 0.60, P = 0.001), and postoperative LIV tilt (r = 0.65, P = 0.0002). The radiographic parameters that correlated with postoperative LIV-CSVL were: preoperative LIV-CSVL (r = 0.57, P = 0.017), preoperative LIV tilt (r = 0.40, P = 0.04), and postoperative LIV tilt (r = 0.46, P = 0.015). The radiographic parameters correlating to LIV translation were preoperative LIV-CSVL (r = 0.88, P < 0.001) and preoperative C7-CSVL (r = 0.44, P = 0.02). Conclusion. LIV tilt is a very important radiographic parameter that strongly correlates to postoperative global and regional coronal balance. In patients with Lenke 5C curves undergoing posterior spinal fixation using pedicle screw constructs, preoperative LIV tilt equal to or exceeding 25° and failure of postoperative LIV tilt to reduce below 8° correlate with a high risk of developing postoperative global coronal imbalance.

Correction of Lenke 5 adolescent idiopathic scoliosis using pedicle screw instrumentation: does implant density influence the correction?

Study Design. A single-center, retrospective study of 39 consecutive patients with Lenke 5 adolescent idiopathic scoliosis (AIS), all operated by a single surgeon using identical surgical technique and type of instrumentation (pedicle screws). Objective. The objective of this study is to evaluate the effect of implant density on coronal and sagittal correction in the treatment of Lenke 5 AIS. Summary of Background Data. There is an increasing trend in the use of pedicle screws in spinal corrective surgery. It is reported that decreased numbers of pedicle screws (low screw density) have no effects on the clinical outcomes for patients with Lenke 1 AIS. However, no previous studies have investigated the effects of reduced density of screw implantation on coronal correction and sagittal lumbar lordosis in patients with Lenke 5 AIS. Methods. Thirty-nine consecutive patients with Lenke 5 AIS underwent single-stage posterior correction and instrumented spinal fusion with pedicle screw fixation between 2006 and 2010. The radiographs were analyzed before surgery, immediately after surgery, and at the 2-year follow-up. General information of patients was recorded. Pearson correlation analysis was used to analyze the correlation between implant density, coronal Cobb angle correction, and correction index (postoperative correction/preoperative curve flexibility). The relations between implant density and magnitude of coronal and sagittal curve correction were also investigated. Results. The mean patient age at the time of operation was 14.5 years. The mean preoperative lumbar curve of 48.5° ± 9.2° was corrected to 13.7° ± 7.2° (72% correction) at a 2-year follow-up. There was a significant correlation between implant density and curve correction (r = 0.43, P < 0.05). No correlation was detected between implant density and correction index (r = −0.21, P = 0.20), and there was also no correlation between implant density and magnitude of sagittal curve correction (r = 0.065, P = 0.693). Conclusion. Without curve flexibility taken into consideration, implant density is positively correlated with thoracolumbar or lumbar coronal Cobb curve correction. No significant correlation is found between screw density and correction index, if the effect of the flexibility was eliminated. There was no association between implant density and magnitude of sagittal curve correction before and after surgery. Level of Evidence: 4

Knockdown of Akt Sensitizes Osteosarcoma Cells to Apoptosis Induced by Cisplatin Treatment

Akt plays an important role in the inhibition of apoptosis induced by chemotherapy and other stimuli. We therefore investigated if knockdown of Akt2 promoted drug-induced apoptosis in cultured osteosarcoma cells in vitro. SAOS-2 cells were transfected with Akt2 siRNA. The sensitivity of the transformed cell line to the chemotherapeutic drug cisplatin was assessed. Reduced expression of Akt2 did not directly inhibit the growth rate of the transfected cells; however, it significantly increased their sensitivity to cisplatin. Knockdown of Akt2, together with cisplatin treatment, promoted the expression of p53 up-regulated modulator of apoptosis (PUMA). It is possible that the augmentation of cisplatin cytotoxicity may be mediated by PUMA activation. The results of this study suggest that knockdown of Akt2 expression may have therapeutic applications in enhancing the efficacy of chemotherapy in patients with osteosarcoma.

Development of a simplified Chinese version of the hip disability and osteoarthritis outcome score (HOOS): cross-cultural adaptation and psychometric evaluation

Osteoarthritis (OA) has a profound impact on health-related quality of life 1 . Increasing importance has been attached to utilization of disease-specific, self-reported outcome measures 2 , such as the Hip Disability and Osteoarthritis Outcome Score (HOOS) instrument 3 . China is the most populous country in the world with 1.3 billion people. Hence, we translated and adapted the HOOS into a Simplified Chinese version (SC-HOOS) and validated it in a cohort of native Chinese-speaking patients with hip OA, relative to the Short Form Health Survey (SF-36), a visual analog scale (VAS), and the Harris hip score (HHS) test. Psychometric testing for internal consistency, testeretest reliability, construct validity, and responsiveness was conducted. The SC-HOOS showed satisfactory internal consistency, testeretest reliability, construct validity, and responsiveness when evaluated in Chinese-speaking patients with hip OA.

Using side-bending radiographs to determine the distal fusion level in patients with single thoracic idiopathic scoliosis undergoing posterior correction with pedicle screws.

Study Design Prospective. Objectives To evaluate a strategy to determine the distal fusion level in posterior pedicle screw correction of single thoracic idiopathic scoliosis. Summary of Background Data No standard method for selecting the lowest instrumented vertebra (LIV) for the correction of thoracic adolescent idiopathic scoliosis with posterior all-pedicle screw instrumentations exists. Methods Thirty-eight patients with single right thoracic (Lenke 1A) adolescent idiopathic scoliosis undergoing posterior pedicle screw fixation were studied. The LIV was determined using guidelines based on preoperative side-bending radiographs. In brief, (1) the whole thoracic Cobb curve should be included in the fusion mass, and the LIV should not be superior to the lower-end vertebra of the Cobb measurement. (2) On the right side-bending radiographs, the LIV should be derotated to neutral in skeletally immature (Risser 0 to 3) patients and the disc immediately below the LIV must open on the left side by at least 5 degrees. (3) On the left side-bending radiographs, the disc immediately below the LIV must be open on the right side by at least 0 degree. The first segment meeting the criteria when proceeding from the lower-end vertebra caudally is chosen as the LIV. Outcomes were based on the standing radiographs. Results Minimum follow-up was 2 years. The mean preoperative thoracic curve was 48.4±9.2 degrees and 12.6±6.1 degrees at final follow-up, resulting in a mean correction of 74.7%±8.5%. The mean preoperative compensatory lumbar curve of 23.7±7.5 degrees was 6.3±4.8 degrees at final follow-up. A change in lumbar lordosis from −41.2±11.9 degrees preoperatively to −38.2±9.9 degrees at final follow-up occurred. All patients achieved coronal balance and no decompensation or adding-on phenomenon was observed. Compared with the recommended fusion end by the Harrington stable zone method, 86.9% patients were saved 1 or more motion segment. Conclusions The method described was effective in obtaining satisfactory curve correction, adequate trunk balance, and preservation of motion segments.

Radiographic Parameters in Adult Degenerative Scoliosis and Different Parameters Between Sagittal Balanced and Imbalanced ADS Patients.

Abstract A retrospective study. To summarize and describe the radiographic parameters of adult degenerative scoliosis (ADS) and explore the radiological parameters which are significantly different in sagittal balanced and imbalanced ADS patients. ADS is the most common type of adult spinal deformity. However, no comprehensive description of radiographic parameters in ADS patients has been made, and few studies have been performed to explore which radiological parameters are significantly different between sagittal balanced and imbalanced ADS patients. Medical records of ADS patients in our outpatient clinic from January 2012 to January 2014 were reviewed. Demographic data including age and sex, and radiographic data including the coronal Cobb angle, location of apical vertebra/disc, convexity of the curve, degree of apical vertebra rotation, curve segments, thoracic kyphosis (TK), lumbar lordosis (LL), thoracolumbar kyphosis (TL), sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI), sagittal vertical axis (SVA), and PI minus LL (PI − LL) were reviewed to make comprehensive description of radiographic parameters of ADS. Furthermore, patients were divided into 2 groups according to whether the patients’ sagittal plane was balanced: Group A (imbalanced, SVA > 5 cm) and Group B (balanced, SVA ⩽ 5 cm). Demographic and radiological parameters were compared between these 2 groups. A total of 99 patients were included in this study (Group A = 33 and Group B = 66; female = 83 and male = 16; sex ratio = 5:1). The median of age were 67 years (range: 41–92 years). The median of coronal Cobb angle and length of curve was 23 (range: 10–75°) and 5 segments (range: 3–7), respectively. The most common location of apical vertebra was at L2 to L3 (81%) and the median of degree of apical vertebra rotation was 2° (range: 1–3). Our study also showed significant correlations between coronal Cobb angle and curve segments (r = 0.23, P < 0.005) and degree of apical vertebra rotation (r = 0.53, P < 0.005). With regard to the sagittal balance, there were significant differences in age, LL, PT, coronal Cobb angle, degree of apical vertebra rotation, and PI − LL between imbalanced group and balanced group (all P < 0.05); however, no significant difference was observed in gender, TK, TL, SS, and PI. Our study provided the general radiographic parameters of ADS. Weak or moderate but significant correlations between coronal Cobb angle and curve segments and degree of apical vertebra rotation were observed. Furthermore, age, coronal Cobb angle, LL, PT, and PI − LL were significantly different between sagittal balanced and imbalanced ADS patients.

A valid cross-culturally adapted simplified Chinese version of the Quebec Back Pain Disability Scale

OBJECTIVE To evaluate the reliability and validity of the simplified Chinese version of the Quebec Back Pain Disability Scale (SC-QDS). STUDY DESIGN AND SETTING The QDS was translated and cross-culturally adapted into SC following international guidelines. The SC-QDS was completed by 114 patients with low back pain (LBP) and 65 healthy controls, along with the SC Oswestry Disability Index (SC-ODI) and visual analogue scale (VAS). Psychometric evaluation included homogeneity and reproducibility by internal consistency and test-retest reliability and construct validity by calculating the Pearsons correlation coefficients among QDS, SC-ODI, and VAS. Discriminative validity was determined by students t-test. RESULTS SC-QDS scores were well distributed, with no floor or ceiling effects. Internal consistency was excellent (Cronbach α 0.976). The items and overall SC-QDS were correlated (r=0.640-0.898 and P<0.0001). Intraclass correlation coefficient of test-retest reliability was excellent (0.987, 95% confidence interval: 0.978-0.992). Construct validity was confirmed by high correlation of SC-QDS and SC-ODI (r=0.901 and P<0.0001) and VAS (r=0.770 and P<0.0001) scores, as was discriminative validity by significantly different SC-QDS scores for patients with LBP and controls (46.3 ± 19.9 vs. 14.6 ± 8.5 and P<0.0001). CONCLUSIONS The SC-QDS has good internal consistency, test-retest reliability, and construct and discriminative validity. The SC-QDS is appropriate for clinical and research uses with Chinese-speaking patients with LBP in mainland China.

Using precisely controlled bidirectional orthopedic forces to assess flexibility in adolescent idiopathic scoliosis: comparisons between push-traction film, supine side bending, suspension, and fulcrum bending film.

Study Design. A prospective study. Objective. To validate the effectiveness of push-traction film (PTF) in assessment of curve flexibility in adolescent idiopathic scoliosis. Summary of Background Data. There is no agreement among surgeons about the most advantageous method in flexibility evaluation of scoliosis. As all methods available provide the orthopedic force from one direction and use a single torque, it is difficult for them to achieve the postoperative correction; also they could not meet the needs for different types of curves. Methods. Precisely controlled bidirectional (push and traction) orthopedic forces were applied for curve flexibility evaluation in 31 consecutive adolescent idiopathic scoliosis patients. The correction rate (CR) of postoperation, supine side-bending, suspension, and fulcrum bending radiographs were compared with PTF in instrumented main thoracic (MT) and thoracolumbar/lumbar curves. Correlation and linear regression analyses were also been done to find the best predictor among the four methods. Results. In MT group, CR of PTF was significantly higher than that of side bending (P = 0.010) and suspension (P = 0.000) but not significantly different from that of fulcrum bending (P = 0.335). In TL/L group, CR of PTF was significantly higher than that of suspension (P = 0.000), but not significantly different from that of side bending (P = 0.681) and fulcrum bending (P = 0.382). There was no significant difference between CR of PTF and postoperation in both MT (P = 0.122) and TL/L (P = 0.068) groups. Correlation and linear regression analyses showed that PTF provided the highest correlation of the four methods, with the postoperative angle in bothMT (r = 0.957) and MT/L group (r = 0.779). Conclusion. To our knowledge, this was the first report about using precisely controlled bidirectional correction forces for curve flexibility evaluation. Although it did not achieve the best CR among the four methods studied, correlation and regression analyses confirmed that PTF was a more stable and accurate method to predict flexibility. We believe that further exploration of a more rational push-traction force ratio would help to obtain a better flexibility.

High selenium may be a risk factor of adolescent idiopathic scoliosis

The pathogenesis of adolescent idiopathic scoliosis (AIS) remains little understood. Previous work has shown that guppy fish is an ideal animal model of idiopathic scoliosis which has similar epidemiological and morphological characteristic with AIS. However, some research speculated that the high-selenium environment could also induce idiopathic-type scoliosis of fish. We believe that the high-selenium related deformity of spine and guppy curveback syndrome may have the same pathogenesis. And high selenium may be a risk factor of AIS.

Validation of the simplified chinese version of the functional rating index for patients with low back pain.

Study Design. Cross-cultural translation and psychometric testing of the Functional Rating Index (FRI). Objective. To evaluate the reliability and validity of the adapted simplified Chinese FRI (SC-FRI) for patients with low back pain (LBP). Summary of Background Data. The FRI is a reliable and valid instrument to assess the perception of function and pain for patients with LBP. However, there is no culturally adapted, reliable, and validated FRI for use in mainland China. Methods. The translation and cross-cultural adaptation were performed following international guidelines. The SC-FRI was administered to 115 patients with LBP along with the simplified Chinese version of the Oswestry Disability Index, 36-Item Short Form Health Survey, and the visual analogue scale. Psychometric testing included internal consistency, test-test reliability, concurrent criterion validity, and construct validity. Results. A high completion rate of 96% and no floor or ceiling effects were noted for the SC-FRI. The internal consistency was good (i.e., Cronbach &agr; = 0.897 for the overall SC-FRI; range, 0.851–0.890, if an item was deleted). Test-retest reliability was excellent, with an intraclass correlation coefficient of 0.948 (95% confidence interval, 0.917–0.968). Concurrent criterion validity assessment demonstrated that the SC-FRI significantly correlated with the visual analogue scale (r = 0.852, P < 0.0001) and the simplified Chinese version of the Oswestry Disability Index (r = 0.958, P < 0.0001). Construct validity was confirmed by the significant Pearson correlation between the SC-FRI and Physical Functioning (r = −0.802, P < 0.0001), Bodily Pain (r = −0.698, P < 0.0001), Social Functioning (r = −0.573, P < 0.0001), Role-Physical (r = −0.503, P < 0.0001), and General Health (r = −0.502, P < 0.0001) domains of the 36-Item Short Form Health Survey. Conclusion. The SC-FRI showed excellent reliability and validity in the evaluation of pain and the functional health status of Chinese-speaking patients with LBP. It is simple and easy to use and can be recommended in clinical and research practice in mainland China.