Mast Cells and Their Related Gene HK-1 are Closely Associated with Discogenic Low Back Pain: A Bioinformatics and Clinical Sample Study.

Background: Low back pain (LBP) is primarily caused by intervertebral disc degeneration (IVDD). Immune cells penetrating nucleus pulposus (NP) tissues may play an important role in generating IVDD and LBP. Methods: The clinical data from 100 cases of IVDD patients was initially analyzed retrospectively. Subsequently, peripheral blood and NP tissues from 41 IVDD patients were gathered for a validated investigation. Among them, ribosome-removed-RNA sequencing (RNA-seq) was performed on 10 cases of NP tissues of specific classifications (VAS 3 and Pfirrmann 3 were used as the controls, while patients with VAS 6 and Pfirrmann 5 were used as the experimental group). Differentially expressed genes (DEGs) were identified for the subsequent bioinformatics analysis. Further methods to confirm the underlying cause of discogenic LBP included mast cell immunohistochemistry (IHC), 12 cytokine detection, Western blot (WB), and real-time polymerase chain reaction (RT-PCR). Results: Discogenic LBP and IVDD severity are strongly associated, and immunological cell infiltration has been demonstrated to be a significant factor in LBP by bioanalytical research. Tryptase-positive mast cells were found to be significantly more abundant in the VAS 6 NP tissues of IVDD patients than in the VAS 3 NP tissues. It was initially demonstrated that IVDD and LBP were significantly impacted by hemokinin-1 (HK-1), the mast cell-related gene. Furthermore, blood levels of interleukin 12 p70 (IL-12P70) are noticeably elevated and strongly correlated with HK-1, indicating that HK-1 may be involved in the regulation of mast cell activity and IL-12P70 production. Conclusion: The severity of LBP was observed to be positively correlated with the IVDD Pfirrmann grading. Further research indicates that patients with IVDD may experience persistent low back pain due to HK-1 activation of mast cells and the release of the cytokine IL12P70. This work will offer new insights into the diagnosis and treatment of discogenic LBP.

[Effect of Kümmell's disease with kyphosis on spinal-pelvic sagittal parameters].

OBJECTIVE: To explore the effect of Kümmell's disease with kyphosis on the sagittal morphology of the spine-pelvis. METHODS: A retrospective analysis of 34 patients of Kümmell's disease with kyphosis （Kümmell group） admitted from August 2015 to September 2022, including 10 males and 24 females with an average age of （71.1±8.5） years old. A control group of 37 asymptomatic population aged （69.3±6.7） years old was matched. Spinal-pelvic sagittal parameters were measured on the anterior-posterior and lateral X-rays of the whole spine in the standing position, including segmental kyphosis（SK） or thoracolumbar kyphosis（TLK）, thoracic kyphosis（TK）, lumbar lordosis（LL）, pelvic incidence（PI）, pelvic tilt（PT）, sacral slope（SS）, sagittal vertical axis（SVA）, T1 pelvic angle（TPA） and PI-LL. Vertebral wedge angle（WA） in Kümmell was measured and differences in parameters among groups were analyzed and the relationship between spino-pelvic parameters and WA, SK were also investigated. RESULTS: TK, SK, PT, SVA, TPA and PI-LL in Kümmell group were significantly larger than those in control group （P<0.05）, LL and SS in Kümmell group were significantly decreased than those in control group （P<0.05）, and there was no significant difference in PI between two groups （P>0.05）. In Kümmell group, WA（30.8±5.9）° showed a positive correlation with SK and TK（r=0.366, 0.597, P<0.05）, and SK was significantly correlated with LL and SS（r=0.539, -0.591, P<0.05）. Strong positive correlation between LL and PI, SS, SVA, TPA, PI-LL were also confirmed in patients with Kümmell with kyphosis（r=0.559, 0.741, -0.273, -0.356, -0.882, P<0.05）. CONCLUSION: Patients with Kümmell with kyphosis not only have segmental kyphosis, but also changes the overall spinal-pelvic sagittal parameters, including loss of lumbar lordosis, pelvic retrorotation, trunk forward tilt. The surgical treatment of Kümmell disease should not only pay attention to the recovery of the height of the collapsed vertebra, but also focus on the overall balance of the spine-pelvic sagittal plane for patients with kyphosis.

[Effect of morphological changes in the sagittal plane of vertebrae and discs on degenerative kyphodeformity].

OBJECTIVE: To explore the effects of morphological changes such as vertebral wedge deformation and disc degeneration (collapse) on adult thoracolumbar/lumbar degenerative kyphosis(TL/LDK) deformity. METHODS: A retrospective analysis of 32 patients with spinal TL/LDK deformity admitted from August 2015 to December 2020, including 8 males and 24 females, aged 48 to 75(60.3±12.4) years old. On the long-cassette standing upright lateral radiographs, the coronal Cobb angle, sagittal thoracic lumbar/lumbar kyphosis angle(KA) of spine were measured, and the height and wedge parameters of apex vertebral(AV) and two vertebrae(AV-1, AV-2, AV+1, AV+2) above and below AV and the intervertebrae and the intervertebral disc(AV-1D, AV-2D, AV+1D, AV+2D) were evaluated, involving anterior vertebral body height(AVH), posterior vertebral body height(PVH), vertebral wedge angle(VWA), ratio of vertebral wedging(RVW), anterior disc height(ADH), posterior disc height(PDH), disc wedge angle(DWA), ratio of disc wedging(RDW), and DWA/KA. RESULTS: The average angle of kyphosis was (44.2±19.1)°. A significant decrease in anterior height of vertebral was observed compared to the posterior height of vertebral(P<0.005). There was no significant difference in anterior and posterior height of discs. The vertebral wedging ratio/contribution ratio:AV-2(14.98±10.95)%/(14.21±8.08)%, AV-1(21.08±12.39)%/(18.09±7.38)%, AV(26.94±11.94)%/(25.52±8.64)%, AV+1(24.19±8.42)%/(20.82±8.69)%, AV+2(20.56±7.80)%/(15.60±9.71)%, total contribution(94.23±22.25)%, the disc wedging ratio/contribution ratio:AV-2D(2.88±2.57)%/(5.27±4.11)%, AV-1D(1.98±1.41)%/(2.29±2.16)%, AV+1D(-5.54±3.75)%/(-0.57±0.46)%, AV+2D(-8.27±4.62)%/(-1.22±1.11)%, total contribution (5.77±4.79)%. And the contribution rate of AV was significantly higher than that of adjacent vertebral(P<0.05). CONCLUSION: The vertebral body and intervertebral disc shape both have influence on thoracolumbar kyphosis. However, the contribution of vertebral morphometry to the angle of TL/LDK deformity is relatively more important than the disc. The contribution of the wedge change of the AV to the TL/LDK deformity is particularly significant.

RP11-296E3.2 acts as an important molecular chaperone for YBX1 and promotes colorectal cancer proliferation and metastasis by activating STAT3.

BACKGROUND: RP11-296E3.2 is a novel long noncoding RNA (lncRNA) associated with colorectal cancer (CRC) metastasis, that was reported in our previous clinical studies. However, the mechanisms of RP11-296E3.2 in colorectal tumorigenesis remain elusive. METHODS: RNA sequencing (RNA-seq), Fluorescence in situ hybridization (FISH), Transwell assays and others, were performed to evaluate the function of RP11-296E3.2 for proliferation and metastasis in vitro. In situ and metastatic tumor models were performed to evaluate the function of RP11-296E3.2 for proliferation and metastasis in vivo. RNA-pulldown, RNA-interacting protein immunoprecipitation (RIP), tissue microarray (TMA) assay, a luciferase reporter assay, chromatin immunoprecipitation (ChIP) and others were performed to explore the mechanisms by which RP11-296E3.2 regulates CRC tumorigenesis. RESULTS: RP11-296E3.2 was confirmed to be associated with CRC cell proliferation and metastasis in vitro and in vivo. Mechanistically, RP11-296E3.2 directly bound to recombinant Y-Box Binding Protein 1 (YBX1) and enhanced signal transducer and activator of transcription 3 (STAT3) transcription and phosphorylation. YBX1 promoted the CRC cell proliferation and migration, while knockdown of RP11-296E3.2 attenuated the effects of YBX1 on CRC cell proliferation, and metastasis and the expression of several related downstream genes. We are the first to discover and confirm the existence of the YBX1/STAT3 pathway, a pathway dependent on RP11-296E3.2. CONCLUSION: Together, these novel findings show that the RP11-296E3.2/YBX1 pathway promotes colorectal tumorigenesis and progression by activating STAT3 transcription and phosphorylation, and suggest that RP11-296E3.2 is a potential diagnostic biomarker and therapeutic target in CRC.

Long non-coding RNA DANCR modulates osteogenic differentiation by regulating the miR-1301-3p/PROX1 axis.

The balance of osteoblasts and marrow adipocytes from bone marrow mesenchymal stem cells (BM-MSCs) maintains bone health. Under aging or other pathological stimuli, BM-MSCs will preferentially differentiate into marrow adipocytes and reduce osteoblasts, leading to osteoporosis. Long non-coding RNA differentiation antagonizing non-protein coding RNA (DANCR) participates in the osteogenic differentiation of human BM-MSCs, but the mechanism by which DANCR regulates the osteogenic differentiation of human BM-MSCs has not been fully explained. We observed that DANCR and prospero homeobox 1 (PROX1) were downregulated during osteogenic differentiation of human BM-MSCs, while miR-1301-3p had an opposite trend. DANCR overexpression decreased the levels of alkaline phosphatase, RUNX2, osteocalcin, Osterix in BM-MSCs after osteogenic induction, but DANCR silencing had the opposite result. Moreover, DANCR sponged miR-1301-3p to regulate PROX1 expression. miR-1301-3p overexpression reversed the suppressive role of DANCR elevation on the osteogenic differentiation of human BM-MSCs. Also, PROX1 elevation abolished the promoting role of miR-1301-3p overexpression on the osteogenic differentiation of human BM-MSCs. In conclusion, DANCR suppressed the osteogenic differentiation of human BM-MSCs through the miR-1301-3p/PROX1 axis, offering a novel mechanism by which DANCR is responsible for the osteogenic differentiation of human BM-MSCs.

Lumbar Retrolisthesis in Aging Spine: What are the Associated Factors?

STUDY DESIGN: A retrospective radiographic study. OBJECTIVE: The aim of this study is to demonstrate that lumbar retrolisthesis serves as an important compensatory mechanism and to identify the possible factor related to lumbar retrolisthesis. SUMMARY OF BACKGROUND DATA: Lumbar instability is one of the common degenerative changes, which presents as 2 radiologic features: anterolisthesis and retrolisthesis. Compared with the extensive studies on anterolisthesis, limit data are available on the characteristics and clinical relevance of lumbar retrolisthesis. MATERIALS AND METHODS: In this study, 105 adult patients with low back pain were prospectively recruited, of which 60 patients had retrolisthesis (group 1) and 45 patients had anterolisthesis (group 2). Another 40 healthy age-matched adults (group 3) were also included to serve as the control group. Sagittal spinopelvic parameters were measured from the standing lateral radiograph, including thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), lumbar lordosis (LL), pelvic incidence (PI), sacrum slope (SS), pelvic tilt (PT), sagittal vertical axis (SVA), spinosacral angle (SSA), and C7 tilt (C7T). In addition, disk degeneration was quantitatively evaluated by Pfirrmann score on T2-weighted magnetic resonance images in patients with retrolisthesis. RESULTS: For all the sagittal parameters, SVA, PI, SS, and LL in retrolisthesis group were found to be significantly lower than those in the anterolisthesis group and in the control group, respectively (P<0.05), whereas TLK in retrolisthesis group was significantly larger than other 2 groups (P<0.01). In addition, the average Pfirrmann disk score was 2.11 at levels with retrolisthesis indicating that the disks were not severely degenerated. CONCLUSIONS: Lumbar retrolisthesis, together with thoracolumbar kyphosis, appears to be associated with mechanisms associated with regulation of sagittal balance. Low PI and disk instability due to degeneration may contribute to the development and progression of retrolisthesis.

Vertebral coplanar alignment technique: a surgical option for correction of adult thoracic idiopathic scoliosis.

PURPOSE: Previous studies have demonstrated vertebral coplanar alignment (VCA) as an effective surgical option for adolescent idiopathic scoliosis (AIS). The purpose of this study is to analyze the outcome of VCA for the surgical correction of adult idiopathic scoliosis (AdIS). METHODS: 35 AdIS patients (mean age: 24.2 years) undergoing VCA-instrumentation were reviewed. The main thoracic curve and thoracic kyphosis (TK, T5-T12) were evaluated preoperatively, immediate postoperatively, and at the final follow-up (>1 year). All patients were stratified by the TK modifier before surgery: "+" (TK, >40°), "-" (TK, <10°), and "N" (TK, 10°-40°) for normal. The apical vertebral body-to-rib ratio (AVB-R), rib hump (RH), and rotational angle to sacrum (RAsac) were measured to assess the correction of rotational deformity. Quality of life was evaluated with SRS-20 questionnaires. RESULTS: The main thoracic curve (59.1° vs. 19.3°, P < 0.001) and rotational deformity (AVB-R: 2.4 vs. 1.7 %, P < 0.001, RH: 34.9 vs. 19.1 mm, P < 0.001, RAsac: 19.6° vs. 11.9°, P < 0.001) were significantly reduced with surgery. Sagittal deformity improved significantly in group "+" (51.4° vs. 31.6°, P < 0.001) and group "-" (6.2° vs. 20.1°, P < 0.001), while no significant postoperative change in TK was observed in group "N" (23.5° vs. 26.3°, P = 0.270). Patients were followed for an average of 18.7 months with no significant loss of correction. SRS scores improved greatly from 57.7 preoperatively to 71.6 at the final follow-up. CONCLUSIONS: VCA can be effectively used for the correction of the coronal and rotational deformity, with better sagittal profile restoration in adult thoracic idiopathic scoliosis with sagittal malalignment.

[Restoration of the difference value of pelvic incidence and lumbar lordosis in degenerative scoliosis patients: its influence in maintaining sagittal profile and improving quality of life].

OBJECTIVE: To evaluate the role that post-operative difference value of pelvic incidence and lumbar lordosis (PI-LL) played on loss of correction, implant failure and health-related quality of life during follow-up in degenerative scoliosis patients. METHODS: Retrospective review of 62 patients (average age (57 ± 10) years, 11 male and 51 female patients) with degenerative scoliosis who underwent one stage posterior surgical instrumentation in the affiliated Drum Tower Hospital of Nanjing University Medical School from January 2005 to December 2011. The mean follow-up duration was 4.2 years. Long-cassette standing upright sagittal radiographs were obtained before and after operation and at the last follow-up. At the last follow-up, visual analogue scale and Oswestry disability index were collected. Based on post-operative PI-LL, patients were divided into two groups: group A (-9° < post-operative PI-LL<9°) and group B (post-operative PI-LL < -9°or post-operative PI-LL>9°). Independent t test and χ(2) test were performed for statistical analysis. For all statistical analysis, the level of significance was set at P < 0.05. RESULTS: No difference was observed in terms of loss of correction between two groups during follow-up. More implant failure were observed in group B (15.63% vs. 6.7%, χ(2) = 21.85, P = 0.012). In addition, patients with better PI-LL matching came with better visual analogue scale (3.9 ± 2.4 vs. 5.2 ± 3.3, F = 0.089, P = 0.024). CONCLUSION: Worse quality of life and increased risk for implant failure during follow-up may be related to mismatched PI-LL.

Will immediate postoperative imbalance improve in patients with thoracolumbar/lumbar degenerative kyphoscoliosis? A comparison between Smith-Petersen osteotomy and pedicle subtraction osteotomy with an average 4 years of follow-up.

STUDY DESIGN: A retrospective radiographical study. OBJECTIVE: To compare compensatory behavior of coronal and sagittal alignment after pedicle subtraction osteotomy (PSO) and Smith-Petersen osteotomy (SPO) for degenerative kyphoscoliosis. SUMMARY OF BACKGROUND DATA: There was a paucity of literature paying attention to the postoperative imbalance after PSO or SPO and natural evolution of the imbalance. METHODS: A retrospective study was performed on 68 consecutive patients with degenerative kyphoscoliosis treated by lumbar PSO (25 patients) or SPO (43 patients) procedures at a single institution. Long-cassette standing radiographs were taken preoperatively, postoperatively, and at the last follow-up and radiographical parameters were measured. The lower instrumented vertebral level and level of osteotomy were compared between the patients with and without improvement. RESULTS: Negative sagittal vertical axis (SVA) was observed in the PSO group postoperatively, implying an overcorrection of SVA. This negative SVA improved spontaneously during follow-up (P < 0.05). Coronal balance was found to worsen immediately postoperatively in the SPO group (P < 0.05). At the last follow-up, spontaneous improvement was observed in 15 patients and the average coronal balance decreased to 16.35 mm. For the 15 patients with improved coronal balance, fusion at L5 or above was more common compared with the 11 patients with persisted postoperative imbalance (P = 0.027), whereas no difference in term of levels of osteotomy was found (P > 0.05). CONCLUSION: The overcorrection of SVA is more often seen in the PSO group. The coronal imbalance is more likely to occur in the SPO group. The postoperative sagittal imbalance often spontaneously improves with time. Lower instrumented vertebra at S1 or with pelvic fixation should be regarded as potential risk factors for persistent coronal imbalance in patients with SPO. LEVEL OF EVIDENCE: 3.

Scoliosis related information on the internet in China: can patients benefit from this information?

BACKGROUND: There has been an increasing popularity of searching health related information online in recent years. Despite that considerable amount of scoliosis patients have shown interest in obtaining scoliosis information through Internet, previous studies have demonstrated poor quality of online information. However, this conclusion may vary depending on region and culture. Since China has a restricted Internet access outside of its borders, the aim of this study is to evaluate the quality of scoliosis information available online using recognized scoring systems and to analyze the Internet as a source of health information in China. METHODS: A survey-based questionnaire was distributed to 280 respondents at outpatient clinics. Information on demographics and Internet use was collected. Binary logistic analysis was performed to identify possible predictors for the use of Internet. In addition, the top 60 scoliosis related websites assessed through 4 search engines were reviewed by a surgeon and the quality of online information was evaluated using DISCERN score and JAMA benchmark. RESULTS: Use of the Internet as a source for scoliosis related information was confirmed in 87.8% of the respondents. College education, Internet access at home and urban residence were identified as potential predictors for Internet use. However, the quality of online scoliosis related information was poor with an average DISCERN score of 27.9±11.7 and may be misleading for scoliosis patients. CONCLUSION: The study outlines the profile of scoliosis patients who use the Internet as a source of health information. It was shown that 87.8% of the scoliosis patients in outpatient clinics have searched for scoliosis related information on Internet. Urban patients, higher education and Internet access at home were identified as potential predictors for Internet search. However, the overall quality of online scoliosis related information was poor and confusing. Physician based websites seemed to contain more reliable information.

Lumbo-femoral angle: a novel sagittal parameter related to quality of life in patients with adult scoliosis.

PURPOSE: PT and PI-LL sometimes offer limited utility in daily practice when evaluating QOL, especially in outpatient clinics with limited time and equipment facility. This study proposes a novel spino-pelvic parameter, lumbo-femoral angle (LFA). The purpose of this study is to analyze the correlation between LFA and HRQOL in adult scoliosis patients. METHODS: A cohort of 100 asymptomatic adult volunteers and 50 patients with adult scoliosis were prospectively recruited. The following sagittal parameters including thoracic kyphosis (TK), LL, LFA, PI, PT and sacral slope (SS) were measured on the long-cassette standing upright lateral radiographs. Health-related QOL (HRQOL) measures included the VAS, ODI and SF-36 instruments for patients with adult scoliosis. RESULTS: LFA, the novel regional lumbo-sacral parameter, averaged 0.68° ± 4.5° in normal adults with the 95 % CI value of -7° to 7°. Similar intra- and inter-observer intraclass correlations and less measurement time were observed in LFA compared to PI-LL indicating that it is easy to quantitatively evaluate the regional alignment directly from X-ray films. Although LFA in patients with adult scoliosis was found to be significantly larger (11.8° ± 8.7° vs. 0.68° ± 4.5°, p < 0.001), it showed strong correlations with the PT and PI-LL in both groups (p < 0.001). Additionally, a summary of correlations between LFA and QOL measurements was identified (p < 0.05). CONCLUSION: LFA could be considered a novel, user-friendly sagittal parameter, correlated with previously established sagittal spino-pelvic parameters and HRQOL measurements. LFA showed high inter- and intra-observer reliability, faster measurement times and could be easily identified and read. Mean LFA in asymptomatic adult patients was nearly 0° with 95 % CI value of -7° to 7°, and significantly increased in adult scoliosis patients.

Coronal curvature and spinal imbalance in degenerative lumbar scoliosis: disc degeneration is associated.

STUDY DESIGN: A retrospective radiographical study. OBJECTIVE: To determine the association between disc degeneration and spinal malalignment on both coronal and sagittal planes in patients with degenerative lumbar scoliosis (DLS). SUMMARY OF BACKGROUND DATA: In recent years, a thorough understanding of spinal coronal balance and sagittal alignment has become more and more important in treating patients with DLS. Although degeneration of discs has been generally accepted as the main cause of DLS, to date no study has documented the relationships between disc degeneration and the curve magnitude as well as spinal imbalance. METHODS: In this study, 57 patients with DLS were recruited. Degeneration of the apical disc, lower end vertebral (EV) discs and regional lumbar discs (L1-L2 and L5-S1) were quantitatively evaluated by the Pfirrmann score based on T2-weighted magnetic resonance images. Radiographical parameters including Cobb angle, coronal trunk shift, sagittal vertical axis (SVA), thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence, pelvic tilt, and sacral slope were measured from long-cassette standing upright radiographs. Subjects were assigned to 4 groups: both coronal and sagittal balanced (C+ S+); coronal imbalanced but sagittal balanced (C- S+); coronal balanced but sagittal imbalanced (C+ S-); and both coronal and sagittal imbalanced (C- S-). The Spearman correlation was used to identify the relationship between the Pfirrmann score of disc degeneration and radiographical parameters. Analysis of variance 2×2 factorial design was performed to identify the decisive factors affecting coronal and sagittal balance. RESULTS: On the basis of the criteria for each group, 19 patients were assigned to group A (C+ S+), 10 patients to group B (C- S+), 11 patients to group C (C+ S-), and 17 patients to group D (C- S-). The Pfirrmann score of regional lumbar disc degeneration strongly correlated with Cobb angle, SVA, TK, and LL (r = -0.364, -0.386, 0.283, and 0.479, respectively, P < 0.01). Specifically, the Pfirrmann score of apical disc degeneration correlated with Cobb angle, whereas degeneration of lower EV discs correlated with SVA, TK, and LL. On the basis of analysis of variance 2 × 2 factorial design, the score of the lower EV disc degeneration significantly correlated with sagittal balance (P < 0.05). CONCLUSION: This study demonstrated that the lower EV disc degeneration strongly correlated with sagittal imbalance in patients with DLS, implying that disc degeneration may be regarded as a potential risk factor for sagittal imbalance. This result strengthened the importance of not selecting the lower EV as the lower instrumented vertebra during the surgical decision making, which may lead to deterioration of sagittal balance. Disc degeneration was also strongly correlated with sagittal malalignment, as demonstrated by a more positive SVA, decreased TK and LL, providing insight into reasons for low quality of life in elderly patients with DLS.

Analysis of L5 incidence in normal population use of L5 incidence as a guide in reconstruction of lumbosacral alignment.

STUDY DESIGN: Cross-sectional study. OBJECTIVE: To establish a statistic model defining the relationship between L5 incidence (L5I) and pelvic incidence (PI) in normal population and to illustrate the importance of L5I in maintaining the normal sagittal profile of spine. SUMMARY OF BACKGROUND DATA: L5I was proposed for the evaluation of postoperative improvements in high-grade isthmic spondylolisthesis. It has been proven that a postoperative improvement in L5I was correlated with a better surgical outcome, indicating that the restoration of L5I is important in restoring normal sagittal balance and spinal morphology. METHODS: This retrospective study recruited 138 healthy volunteers, who were stratified into 2 groups according to age: adolescent group (13-18 yr) and adult group (19-35 yr). Parameters including PI, pelvic tilt, sacral slope, lumbar lordosis (LL), upper arc of the LL, lower arc of the LL, L5I, lumbosacral angle, and height of L5-S1 disc were measured on the long-cassette standing upright lateral radiographs of the spine and pelvis. The relations between all parameters were determined via the Pearson correlation coefficient (r). Linear regression was applied to model the relationship between PI and L5I. RESULTS: This study demonstrated significant correlation between L5I and PI with a coefficient of 0.818, and a formula based on linear regression was established to estimate the ideal L5I from PI as follows: L5I = 0.725 PI - 12.757. Pelvic tilt, sacral slope, lumbosacral angle, LL, lower arc of the LL, and height of L5-S1 disc were also found strongly correlated with L5I, whereas no correlation was found between upper arc of the LL and L5I. CONCLUSION: Strong correlations were found between L5I and spinopelvic parameters in healthy subjects, indicating that L5I was an important parameter in local lumbosacral alignment. Ideal postoperative L5I could be mathematically calculated by PI according to the formula as follows: L5I = 0.725 PI - 12.757, suggesting that calculated ideal L5I could be regarded as a guide in surgical decision making. LEVEL OF EVIDENCE: 3.

[Effect of intervertebral disc degeneration on spinal flexibility in patients with degenerative lumbar scoliosis].

OBJECTIVE: To investigate degenerative changes of the intervertebral disc and their impact on spinal flexibility in patients with degenerative lumbar scoliosis (DLS). METHODS: Retrospective analysis of 66 patients (average age 58.4 years, 10 males and 56 females) with DLS was conducted from May 2008 to February 2014. For all patients, pre-operative standing X-ray film, Bending X-ray films and thoracolumbar MRI were taken. Cobb's angle was measured in each X-ray film and intervertebral angle was measured in both standing and Bending X-ray films. All discs were graded according to Pfirrmann degeneration grades on T2 weighted saggital MRI imaging. Statistical analyses were performed to determine the correlation between intervertebral disc degeneration with the whole spine flexibility and segmental flexibility. RESULTS: For all 66 subjects, the average Cobb's angle of pre-operative and bending X-ray film was 36° ± 13°, 21° ± 11°, respectively. The average flexibility was 45% ± 15% in our study. Totally 268 discs were graded, including gradeI8, II 68, III 83, IV 91, V 18. In the main curve, there was significant correlation between the average degree of disc degeneration and the whole spine flexibility(r = -0.727, P < 0.01). There was significant correlation between the grade of segmental disc degeneration and segmental flexibility (P < 0.01) . The apical intervertebral disc had the most degeneration (P < 0.01) and worst flexibility (P < 0.01) , compared with other discs in the main curve. CONCLUSIONS: The degree of intervertebral disc degeneration is closely correlated with spinal flexibility in DLS. The more the disc degeneration is, the worse the spinal flexibility becomes.