ObjectiveTo investigate the correlation between the effectiveness and the changes of spine-pelvic sagittal parameters for patients with spondylolisthesis before and after operation. MethodsA retrospective analysis was made on the clinical data of 32 patients with single segmental degenerative lumbar spondylolisthesis at L4 who accorded with the inclusion criteria between June 2011 and January 2014 (trial group). There were 13 males and 19 females, aged 51-67 years (mean, 59 years). According to Meyerding degree, there were 21 cases of degree I, 10 cases of degree Ⅱ, and 1 case of degree Ⅲ. All patients were treated with transforaminal lumbar interbody fusion (TLIF) surgery. Thirty-five healthy adults at the age of 46-67 years (mean, 57 years) were enrolled as normal controls (control group). The standing position lumbar lateral X-ray films (T12-S1, bilateral femoral head) were taken at pre- and post-operation to measure the pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL), disc height (DH), and slip percentage (SP); the visual analogue scale (VAS) and Oswestry disability index (ODI) were recorded. Pearson correlation analysis was used to analyze the correlation between the preoperative various spine-pelvic sagittal parameters and the VAS score and the ODI. After operation, Pearson correlation analysis was used to evaluate the correlation between the changes of these parameters and the improve rates of VAS score and ODI. ResultsAll patients of trial group were followed up 15-22 months (mean, 18 months). At last follow-up, the VAS score, ODI, PT, SS, LL, SP, and DH were significantly improved when compared with preoperative values (P<0.05), except for PI (t=-1.445, P=0.158). There was no significant difference in PT, SS, LL, and DH between trial and control groups at last follow-up (P>0.05); PI was slightly bigger than that of control group (t=8.531, P=0.043). Pearson correlation analysis showed that there was a correlation between spine-pelvic sagittal parameters of PI, PT, SS, and LL (P<0.05); preoperative parameters (except for LL and DH) had correlation with ODI and VAS scores (P<0.05). Postoperative parameters (except for PI) had correlation with the improve rates of ODI and VAS scores (P<0.05), especially for the changes of PT and the improvements of ODI and VAS scores. ConclusionThere is a correlation between the changes of spine-pelvic sagittal parameters at pre- and post-operation and effectiveness in patients with lumbar spondylolisthesis. The correlation between the changes of PT and the improvement rates of ODI and VAS scores is more marked. The good effectiveness is closely related with the improved PT.
ObjectiveTo investigate the changes and relationship of cervical spine sagittal alignment and other spinal-pelvic sagittal parameters in adolescent idiopathic scoliosis. MethodsBetween July 2011 and July 2014, 35 patients with idiopathic scoliosis who met the inclusion criteria underwent posterior pedicle screw instrumentation and fusion. There were 12 males and 23 females with a mean age of 16.2 years (range, 13-20 years), including 16 cases of Lenke type 1, 7 cases of Lenke type 2, 4 cases of Lenke type 3, 3 cases of Lenke type 4, 4 cases of Lenke type 5, and 1 case of Lenke type 6. The average follow-up time was 10.9 months (range, 5-36 months). The pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL), thoracic kyphosis (TK), cervical lordosis (CL), T1 slope, C2 slope, C7 sagittal vertical axis (C7 SVA), C2-7 plumbline (cSVA) were measured on pre-and post-operative standing lateral X-ray film. Based on preoperative CL, the patients were divided into kyphosis group (CL>0°) and lordosis group (CL < 0°); after operation, the patients were divided into restored lordosis (group A), decreased kyphosis (group B), and increased lordosis (group C) after operation. All data about sagittal profile changes were analyzed. The relations between CL and other spinal-pelvic parameters in the kyphosis and lordosis groups before operation were determined via Spearman correlation coefficient. ResultsStatistically significant changes were observed in PT, PI, SS, and LL between at pre-and post-operation (P < 0.05), but no significant difference was found in the other parameters (P>0.05). There were 17 patients in lordosis group and 18 in kyphosis group before operation. Intra-group comparisons showed significant changes in PT, PI, SS, C2 slope, and C7 SVA in lordosis group, and in PT, PI, SS, LL, CL, TK, T1 slope, and C2 slope in kyphosis group (P < 0.05). Subgroup comparisons showed significant changes in CL, TK, C2 slope, C7 SVA, and T1 slope before operation (P < 0.05) and T1 slope at last follow-up between 2 groups (P < 0.05). In kyphosis group, 7 cases (group A) had restored lordosis, 7 cases (group B) had decreased kyphosis, and 4 cases had increased lordosis. In lordosis group, 9 cases (group C) had increased lordosis, 3 cases had decreased lordosis, and 5 cases had kyphotic cervical alignment after operation. Significant difference was found in LL, CL, T1 slope, C2 slope, and C7 SVA of group A, in TK and CL of group B, and in CL and cSVA of group C between pre-and post-operation (P < 0.05). There were significant differences in pre-and post-operative LL between groups A and B (P < 0.05). In lordosis group, there was a strong correlation between CL and C2 slope (P < 0.05) at pre-operation. CL had strong correlation with C2 slope and T1 slope (P < 0.05) at pre-operation in kyphosis group, and CL had moderate correlation with cSVA (P < 0.05). ConclusionCervical sagittal alignment plays an important role in the balance of the spine and pelvis. The change of cervical sagittal alignment has a certain correlation with the change of thoracic kyphosis. Attention to properly maintaining or restoring cervical sagittal lordosis alignment should be considered in preoperative evaluation of adolescent indiopathic scoliosis.
Objective To analyse the correlation between cervical sagittal parameters of cervical spondylotic myelopathy in different sagittal curvature so as to find out representative cervical sagittal alignment parameters by measuring on MRI. Methods A retrospective analysis was made on the clinical data of 88 patients with cervical spondylotic myelopathy between July 2015 and January 2016. The C2-C7 Cobb angle, T1 slope (T1S), and C2-C7 sagittal vertical axis (C2-C7 SVA) were measured on T2-weight MRI. According to C2-C7 Cobb angle, the patients were divided into lordosis group (≥10° Cobb angle, 48 cases) and straightened group (0-10° Cobb angle, 40 cases). Intraclass correlation coefficient (ICC) was used for the reliability of measured data, Pearson correlation analysis for correlation between cervical sagittal parameters. Results ICC was 0.858-0.946, indicating good consistency of measurement parameters. The C2-C7 Cobb angle, T1S, and C2-C7 SVA were (5.6±2.4)°, (22.2±6.7)°, and (10.2±5.4) mm in straightened group, and were (20.1±8.2)°, (23.4±8.9)°, and (8.2±4.6) mm in lordosis group respectively. There was no correlation between the 3 parameters in straighten group (r=0.100,P=0.510 for T1S and C2-C7 Cobb angle;r=–0.100,P=0.500 for T1S and C2-C7 SVA;r=0.080,P=0.610 for C2-C7 Cobb angle and C2-C7 SVA). There was positive correlation between T1S and C2-C7 Cobb angle (r=0.540,P=0.000), negative correlation between T1S and C2-C7 SVA (r=–0.450,P=0.001), and no correlation between C2-C7 Cobb angle and C2-C7 SVA (r=–0.003,P=0.980). Conclusion For cervical spondylotic myelopathy in patients with cervical lordosis, only T1S measurement on MRI can be used as the main parameter to judge the sagittal curvature, but in patients with straightened cervical Cobb angle, measurements of T1S, C2-C7 Cobb angle, and C2-C7 SVA should be taken for the comprehensive evaluation of cervical sagittal curvature.
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.
Objective To review the process of radiographic measurements of sagittal balance and offer reference for the clinical practice. Methods The related literature of spino-pelvic sagittal parameters and their clinical application was reviewed and analyzed from the aspects such as the clinical application, the advantages and disadvantages, and how to use them effectively. Results All parameters have their advantages and disadvantages, and they are influenced by age and race. Sagittal vertical axis can only reflect the global balance, and T1 pelvic angle which accounts for both spinal inclination and pelvic tilt can’t be controlled in the surgery. The correction goal for western people may be not suitable for Chinese. Conclusion The parameters should be used wisely when evaluating the sagittal balance, the global balance and local balance should be considered together and the different groups of people need different correction goals.
Objective To elucidate the relationship between preoperative C7 slope (C7S) and sagittal parameters in anterior cervical discectomy with fusion (ACDF) by imaging. Methods A retrospective analysis of 54 patients (24 males and 30 females) with ACDF for cervical spondylosis between January 2012 and January 2017 was performed. The age ranged from 23 to 71 years (mean, 46.6 years). There were 29 cases of cervical spondylotic radiculopathy and 25 cases of cervical spondylotic myelopathy. The disease duration ranged from 3 to 48 months, with an average of 16.8 months. In the 55 patients, 44 were single-segment ACDF and 10 were double-segment ACDF. Sagittal parameters of cervical spine were measured on cervical X-ray films before operation and at last follow-up, including C2-7 Cobb angle, C2-7 sagittal vertical axis (C2-7 SVA), C7S, and segment Cobb angle (SCobb), and the changes of C2-7 Cobb angle (the difference between the last follow-up and the preoperative angle) were calculated. Pearson correlation was used to analyze the correlation between the parameters before operation and at last follow-up. According to the preoperative median value of C7S (15°), the patients were divided into group A (C7S<15°) and group B (C7S≥15°). The sagittal parameters before and after operation were compared between the two groups. Results All the 54 patients were followed up 6-45 months (mean, 15.5 months). At last follow-up, C7S, C2-7 Cobb angle, C2-7 SVA, and SCobb angle were significantly improved when compared with preoperative values (P<0.05). Correlation analysis showed that the preoperative C7S and SCobb angles were significantly correlated with C2-7 Cobb angle and C2-7 SVA (P<0.05), but there was no significant correlation between C7S and SCobb angle (r=0.049, P=0.724). There was a significant correlation between C7S, C2-7 Cobb angle, and SCobb angle at last follow-up (P<0.05), but there was no significant correlation between C7S and SCobb angles and C2-7 SVA (P>0.05). According to the median value of preoperative C7S, 28 patients in group A had C7S of (11.82±3.60)°, while 26 patients in group B had C7S of (20.77±4.09)°. There was no significant difference in gender and age between the two groups (P>0.05). The preoperative C2-7 Cobb angle and C2-7 SVA in group A were significantly lower than those in group B (P<0.05). There was no significant difference between preoperative SCobb angle and group B (t=0.234, P=0.816). There were no significant differences in C2-7 Cobb angle, C2-7 SVA, and SCobb angle between group A and group B at last follow-up (P>0.05). However, the change of C2-7 Cobb angle in group A was significantly higher than that in group B (t=2.321, P=0.024). Conclusion Preoperative C7S≥15° group has more physiological lordosis before operation, but its postoperative cervical curvature changes less, while ACDF is more conducive to correct the preoperative C7S<15 ° cervical curvature.
Objective To investigate the changes of low back pain (LBP) and spinal sagittal parameters in patients with unilateral Crowe type Ⅳ developmental dysplasia of the hip (DDH) after total hip arthroplasty (THA). Methods The clinical data of 30 patients who met the selection criteria between October 2018 and March 2020 were retrospectively analyzed. Patients were divided into LBP group (16 cases) and control group (14 cases) according to whether there was LBP before operation. There was no significant difference between the two groups of patients in gender, age, body mass index, affected sides, preoperative Harris score (P>0.05). Full-length lateral X-ray films of the spine were taken within 1 week before operation and at 1 year after operation, and the following imaging indicators were measured: sacral slope (SS), lumbar lordosis (LL ), spinal tilt (ST), spine-sacral angle (SSA), sagittal vertebral axis (SVA). The visual analogue scale (VAS) score, lumbar Oswestry disability index (ODI), the Harris score of the hip joint before operation and at 1 year after operation, and the occurrence of postoperative complications were collected and analysed. Results In the LBP group, LBP was relieved to varying degrees at 1 year after operation, of which 13 patients (81.3%) had complete LBP remission; VAS score decreased from 4.9±2.3 preoperatively to 0.3±0.8, ODI decreased from 33.5±22.6 preoperatively to 1.3±2.9, the differences were all significant (t=7.372, P=0.000; t=5.499, P=0.000). There was no new chronic LBP in the control group during follow-up. The Harris scores of the two groups significantly improved when compared with those before operation (P<0.05); there was no significant difference between the two groups at 1 year after operation (t=0.421, P=0.677). There was no significant difference in imaging indexes between the two groups before operation and the difference between pre- and post-operation (P>0.05). At 1 year after operation, ST and SVA in the LBP group, SSA in the control group, and SS in the two groups significantly improved when compared with those before operation (P<0.05); there was no significant difference in the other indexes between the two groups before and after operation (P>0.05). Conclusion Unilateral Crowe type Ⅳ DDH patients with LBP before operation were all relieved of LBP after THA. The relief of LBP may be related to the improvement of spinal balance, but not to lumbar lordosis and its changes.
Objective To investigate the radiological features of degenerative cervical kyphosis (DCK) and the relationship between cervical sagittal parameters. Methods The quality of life scores and imaging data of 89 patients with DCK treated between February 2019 and February 2022 were retrospectively analysed. There were 47 males and 42 females, with an average age of 48.4 years (range, 25-81 years). Quality of life scores included visual analogue scale (VAS) score and neck disability index (NDI). The imaging data included C0-C2 angle, C2-C7 angle, C3-C7 inclination of zygapophyseal joints, C7 slope (C7S), cervical sagittal vertical axis (cSVA), kyphosis range, and kyphosis focal. The patients were grouped by gender, and the differences of the above parameters between the two groups were compared. Pearson correlation was used to analyze the relationship between age, quality of life scores, and cervical sagittal parameters, and the relationship between cervical sagittal parameters. Results The preoperative VAS score was 0-9 (mean, 4.3); NDI was 16%-44% (mean, 30.0%). There was no significant difference in VAS score and NDI between male and female groups (P>0.05). The kyphosis range of cervical spines was C3-5 in 3 cases, C3-6 in 41 cases, C3-7 in 30 cases, C4-6 in 4 cases, C4-7 in 10 cases, C5-7 in 1 case, and the kyphosis focal was mostly located between C4-C5 (78/89, 87.64%). The C3-C7 inclination of zygapophyseal joints were (60.25±5.56)°, (55.42±5.77)°, (53.03±6.33)°, (58.39±7.27)°, and (64.70±6.40)°, respectively. The C0-C2 angle, C2-C7 angle, C7S, and cSVA were (–23.81±6.74)°, (10.15±2.94)°, (15.31±4.59)°, and (2.37±1.19) mm, respectively. The C7S and cSVA of males were significantly larger than females (P<0.05), with no significant difference in other parameters between male and female groups (P>0.05). VAS score and NDI were negatively correlated with C0-C2 angle (P<0.05), and positively correlated with C2-C7 angle and cSVA (P<0.05); VAS score was negatively correlated with C7S (P<0.05). Except VAS, NDI and all cervical sagittal parameters were affected by age. Age was positively correlated with NDI, C7S, and cSVA (P<0.05), and negatively correlated with C0-C2 angle and C2-C7 angle (P<0.05). The correlation analysis of cervical sagittal parameters showed that C0-C2 angle was negatively correlated with C2-C7 angle and cSVA (P<0.05); C7S was negatively correlated with C2-C7 angle (P<0.05) and positively correlated with cSVA (P<0.05). There was no correlation among other parameters (P>0.05). ConclusionThe inclination of zygapophyseal joints of cervical spines of DCK patients is U-shaped in the kyphosis range, and the inclination at the kyphosis focal is the smallest. When cervical degenerative kyphosis occurs, in addition to the interaction of sagittal parameters, age, gender, neck pain, and dysfunction will also affect the cervical sagittal balance. Furthermore, cervical curvature and morphological changes are not purely local problems.
Objective To investigate the changes in spinal-pelvic sagittal parameters from preoperative standing to prone position in old traumatic spinal fractures with kyphosis. Methods The clinical data of 36 patients admitted between December 2016 and June 2021 for surgical treatment of old traumatic spinal fractures with kyphosis, including 7 males and 29 females, aged from 50 to 79 years (mean, 63.9 years), were retrospectively analyzed. Lesion segments included 2 cases of T11, 12 cases of T12, 2 cases of T11, 12, 4 cases of T12 and L1, 12 cases of L1, 2 cases of L2, 1 case of L2, 3, and 1 case of L3. The disease duration ranged from 4 to 120 months, with an average of 19.6 months. Surgical procedures included Smith-Petersen osteotomy in 4 cases, Ponte osteotomy in 6 cases, pedicle subtraction osteotomy in 2 cases, and improved fourth level osteotomy in 18 cases; the remaining 6 cases were not osteotomized. The bone mineral density ranged from −3.0 to 0.5 T, with a mean of −1.62 T. The spinal-pelvic sagittal parameters from preoperative standing to prone positions were measured, including local kyphosis Cobb angle (LKCA), thoracic kyphosis (TK), lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT), and PI and LL mismatch (PI-LL). The kyphotic flexibility=(preoperative standing LKCA−preoperative prone LKCA)/preoperative standing LKCA×100%. Spinal-pelvic sagittal parameters were compared between standing position and prone position before operation, and Pearson correlation was used to judge the correlation between the parameters of standing position and prone position before operation. ResultsWhen the position changed from standing to prone, LKCA and TK decreased significantly (P<0.05), while SS, LL, PT, and PI-LL had no significant difference (P>0.05). Pearson correlation analysis showed that LL was significantly correlated with SS and PI-LL in both standing and prone positions (P<0.05), and the correlation strength between LL and SS in prone position was higher than that in standing position. In the standing position, LKCA was significantly correlated with SS and PT (P<0.05). However, when the position changed from standing to prone, the correlation between LKCA and SS and PT disappeared, while PT and PI-LL was positive correlation (P<0.05). The kyphotic flexibility was 25.13%-78.79%, with an average of 33.85%. Conclusion For the patients of old traumatic spinal fractures with kyphosis, the preoperative LKCA and TK decrease significantly from standing position to prone position, and the correlation between spinal and pelvic parameters also changed, which should be taken into account in the formulation of preoperative surgical plan.
Objective To investigate the imaging characteristics of cervical kyphosis and spinal cord compression in cervical spondylotic myelopathy (CSM) with cervical kyphosis and the influence on effectiveness. Methods The clinical data of 36 patients with single-segment CSM with cervical kyphosis who were admitted between January 2020 and December 2022 and met the selection criteria were retrospectively analyzed. The patients were divided into 3 groups according to the positional relationship between the kyphosis focal on cervical spine X-ray film and the spinal cord compression point on MRI: the same group (group A, 20 cases, both points were in the same position), the adjacent group (group B, 10 cases, both points were located adjacent to each other), and the separated group (group C, 6 cases, both points were located >1 vertebra away from each other). There was no significant difference between groups (P>0.05) in baseline data such as gender, age, body mass index, lesion segment, disease duration, and preoperative C2-7 angle, C2-7 sagittal vertical axis (C2-7 SVA), C7 slope (C7S), kyphotic Cobb angle, fusion segment height, and Japanese Orthopedic Association (JOA) score. The patients underwent single-segment anterior cervical discectomy with fusion (ACDF). The occurrence of postoperative complications was recorded; preoperatively and at last follow-up, the patients’ neurological function was evaluated using the JOA score, and the sagittal parameters (C2-7 angle, C2-7 SVA, C7S, kyphotic Cobb angle, and height of the fused segments) were measured on cervical spine X-ray films and MRI and the correction rate of the cervical kyphosis was calculated; the correlation between changes in cervical sagittal parameters before and after operation and the JOA score improvement rate was analyzed using Pearson correlation analysis. Results In 36 patients, only 1 case of dysphagia occurred in group A, and the dysphagia symptoms disappeared at 3 days after operation, and the remaining patients had no surgery-related complications during the hospitalization. All patients were followed up 12-42 months, with a mean of 20.1 months; the difference in follow-up time between the groups was not significant (P>0.05). At last follow-up, all the imaging indicators and JOA scores of patients in the 3 groups were significantly improved when compared with preoperative ones (P<0.05). The correction rate of cervical kyphosis in group A was significantly better than that in group C, and the improvement rate of JOA score was significantly better than that in groups B and C, all showing significant differences (P<0.05), and there was no significant difference between the other groups (P>0.05). The correlation analysis showed that the improvement rate of JOA score was negatively correlated with C2-7 angle and kyphotic Cobb angle at last follow-up (r=−0.424, P=0.010; r=−0.573, P<0.001), and positively correlated with the C7S and correction rate of cervical kyphosis at last follow-up (r=0.336, P=0.045; r=0.587, P<0.001), and no correlation with the remaining indicators (P>0.05). Conclusion There are three main positional relationships between the cervical kyphosis focal and the spinal cord compression point on imaging, and they have different impacts on the effectiveness and sagittal parameters after ACDF, and those with the same position cervical kyphosis focal and spinal cord compression point have the best improvement in effectiveness and sagittal parameters.