Measurements Of Lumbar Lordosis Research Articles

Automated Measurement of Lumbar Lordosis on Radiographs Using Machine Learning and Computer Vision

Study Design:Cross sectional database study.Objective:To develop a fully automated artificial intelligence and computer vision pipeline for assisted evaluation of lumbar lordosis.Methods:Lateral lumbar radiographs were used to develop a segmentation neural network (n = 629). After synthetic augmentation, 70% of these radiographs were used for network training, while the remaining 30% were used for hyperparameter optimization. A computer vision algorithm was deployed on the segmented radiographs to calculate lumbar lordosis angles. A test set of radiographs was used to evaluate the validity of the entire pipeline (n = 151).Results:The U-Net segmentation achieved a test dataset dice score of 0.821, an area under the receiver operating curve of 0.914, and an accuracy of 0.862. The computer vision algorithm identified the L1 and S1 vertebrae on 84.1% of the test set with an average speed of 0.14 seconds/radiograph. From the 151 test set radiographs, 50 were randomly chosen for surgeon measurement. When compared with those measurements, our algorithm achieved a mean absolute error of 8.055° and a median absolute error of 6.965° (not statistically significant, P > .05).Conclusion:This study is the first to use artificial intelligence and computer vision in a combined pipeline to rapidly measure a sagittal spinopelvic parameter without prior manual surgeon input. The pipeline measures angles with no statistically significant differences from manual measurements by surgeons. This pipeline offers clinical utility in an assistive capacity, and future work should focus on improving segmentation network performance.

Effectiveness of closed reduction and percutaneous fixation of isolated sacral fractures. Functional outcomes and sagittal alignment after 3.6 years in 20 patients

BackgroundDisplaced U- or H-shaped sacral fractures (Roy-Camille Grade II or III) are treated at our institution by early transcondylar traction and manual countertraction, hyperlordosis induced by a pad positioned under the lumbo-sacral junction, and percutaneous ilio-sacral screw fixation. The objective of this study was to evaluate the outcome of this technique used in a level 1 trauma centre.Hypothesis Our early reduction technique provides anatomical reduction of U- or H-shaped sacral fractures by correcting the sagittal malalignment due to the intra-sacral kyphosis, thereby obviating the need for decompression laminectomy and improving neurological outcomes. Material and methodsWe retrospectively evaluated 20 patients treated for U- or H-shaped sacral fractures using our original reduction technique followed by percutaneous fixation only. Mean follow-up was 42.4 months. Mean displacement of the S1 posterior wall was measured on computed tomography scans obtained before and after surgery. Pelvic incidence (PI) and measured lumbar lordosis (LLm) were evaluated on standard radiographs before surgery and on stereoradiographs after surgery. Expected lumbar lordosis (LLe) was computed as LLe=PI+9°. A 25% or greater difference between LLe and LLm defined lumbo-pelvic mismatch. At last follow-up, functional outcomes were assessed based on the Majeed score and the Iowa Pelvic Score (IPS), and a neurological examination was performed. ResultsMean S1 posterior wall displacement in the sagittal and axial planes was 64% and 64.8%, respectively, before surgery versus 5.6% and 15.2%, respectively, after surgery. At last follow-up, LLm was 63.5° and the LLe-LLm difference was 11.2%; only 3 (15%) patients had lumbo-pelvic mismatch at last follow-up. The mean Majeed score and IPS values were 86.6 and 79, respectively, and lumbo-pelvic mismatch correlated significantly with a worse functional outcome defined as a Majeed score below 75 (p=0.0087). At last follow-up, the neurological dysfunctions were improved in 90% of patients, and 70% of patients had achieved a full neurological recovery. Discussion/ConclusionGiven these encouraging findings, we advocate early reduction and percutaneous fixation of U- or H-shaped sacral fractures. Although technically demanding, this method restores the normal pelvic parameters and improves neurological function. Level of evidenceIV, retrospective observational study.

Automated measurements of lumbar lordosis in T2-MR images using decision tree classifier and morphological image processing

Lumbar spine’s lordosis is a very important parameter functionally and clinically; it is a key feature in maintaining the sagittal balance, in addition to its crucial role in evaluating the spinal deformities. The main objective of the current study is to present a fully-automated measurement of the lumbar spine’s lordotic curve angle in T2-MR images. This goal has been achieved by the automatic measurement of lordosis radius at the lumbar spine level by computer-aided methods utilizing data mining classification and image segmentation followed by morphological image processing. The spine has been segmented from the entire image using a machine-learning technique that is based on texture features for recognizing the lumbar-spine pattern. The extracted features were fed to C4.5 decision tree classifier for designing the lumbar-spine recognition system. The resultant classifier’s “if-then” rules have been employed for segmenting the spine region from the entire image. Multiple morphological image processes have been applied to the raw segmentation result to enhance the true positive rate and suppressing the false positive rate. The mean radius of lumbar spine’s curvature has been evaluated by fitting the contours average to the closest circle using least-square fitting algorithm which was followed by calculating the lumbar lordosis curvature angle. The proposed approach has been tested and validated on normal and pathological T2-MR spine images and found to perform effectively. The calculation of lumbar lordosis angles showed a strong correlation with the Cobb angle measurements (R = 93.2%).

Posterior retroperitoneoscopic adrenalectomy for pediatric adrenal tumors

Background/aimsPosterior retroperitoneoscoic adrenalectomy has been reported as an option for adrenal tumor resection but is not commonly performed in children owing to the extreme semikneeling position advocated to flatten the lumbar lordosis in order to achieve adequate retroperitoneal space. As children have smaller lordosis angles, flattening of the lordosis and creation of optimal retroperitoneal space may be achieved with less hip flexion. We used pediatric lumbar lordosis measurements to develop a modified prone jackknife position and report our experiences with this setup for posterior retroperitoneoscopic adrenalectomy for adrenal tumors. MethodsLordosis angles were measured on sagittal computed tomography (CT) and magnetic resonance imaging (MRI) studies of patients with adrenal tumors and compared to normal references. The data were used to develop our modified prone jackknife position. Selected patients with adrenal tumors underwent posterior retroperitoneoscopic adrenalectomy in this position. Patient demographics, diagnoses, operative times, complications, postop analgesia requirements, and length of hospitalization were analyzed. ResultsCT and MRI studies were analyzed for 20 patients with adrenal tumors diagnosed in our institution from 2012 to 2017; median lordosis angle was 27.84° (range: 15.50°–36.48°) — less than reference lordosis angles of respective age groups, and flexion angles of common operating tables. Five patients underwent retroperitoneoscopic adrenalectomy between June 2016 and June 2018. Histological diagnoses were neuroblastoma, adrenal hyperplasia, pheochromocytoma, and adrenal angiomatoid fibrous histiocytoma. Median age was 4 years [range: 1–11]. Median operating time was 137 min [range 111–181 min]. No conversions to open surgery were required. One patient had intraoperative bleeding from the adrenal vein. Only 1 patient required postoperative opioids for analgesia. Median length of hospitalization after surgery was 2 days (range: 2–3 days). ConclusionsPediatric patients can achieve flattening of lumbar lordosis with less extreme positioning. Posterior retroperitoneoscopic adrenalectomy in a modified prone jackknife position is a feasible operation for pediatric patients with small adrenal masses. Type of studyClinical research paper. Level of evidenceLevel III.

Sagittal Imbalance Does Not Influence Cup Anteversion in Total Hip Arthroplasty Dislocations.

Retrospective Cohort. Studies have shown that lumbar fusion procedures are associated with an increased risk of total hip arthroplasty (THA) dislocation. Some have speculated that the increased risk of dislocation is caused by mispositioning of the acetabular component because of spinal sagittal imbalance. Unfortunately, the exact relationship between spinal sagittal balance and cup orientation is unknown. The objective of this study was to investigate the effect of spinal sagittal alignment on cup anteversion in THA dislocation. Patients that suffered a THA dislocation were retrospectively identified. Cross-table lateral hip radiographs were used to measure cup anteversion with normal acetabular anteversion defined as 15±10 degrees. Lateral lumbar spine radiographs were used to measure lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt, and sacral slope. Normal sagittal balance was defined as a PI-LL difference of <10 degrees. The association between sagittal balance and THA characteristics was assessed using Pearson correlation coefficient, χ analysis, and independent t tests. A total of 29 patients had full radiographic imaging. Among these patients, 62.1% dislocated following a primary THA and 37.9% following a revision THA. Abnormal spinal sagittal balance was identified in 20 patients (69.0%). Eight (27.6%) patients had undergone spinal fusion prior to THA. Abnormal cup anteversion was demonstrated in 51.7% of all patients. Presence of a spinal fusion was not associated with cup anteversion, sagittal balance, or time to dislocation. Sagittal balance was not associated with direction of dislocation, time to dislocation, or cup anteversion. A majority of patients with a THA dislocation demonstrated abnormal sagittal balance. However, sagittal balance was not associated with acetabular cup anteversion. As such, the relationship between spinal deformity and dislocation rates after THA may not be because of inaccurate cup orientation.

Radiation-free measurement tools to evaluate sagittal parameters in AIS patients: a reliability and validity study.

This study aimed to evaluate the intra-rater reliability and validity in comparison with the two-dimensional radiography (XR) of inclinometer (INCL) and rasterstereography (RAST) for assessing spinal sagittal angles of AIS patients. Fifty-one AIS patients (13.5 (2.0) years, girls = 32 (63%), Cobb angle = 23.0 (17.4)°) were included in this study. Three repeated measurements of thoracic kyphosis (TK) and lumbar lordosis (LL) were evaluated using the INCL and RAST by the same operator on the same day of the XR examination. Intraclass correlation coefficients (ICC) were used to evaluate the reliability of the INCL and RAST systems. Additionally, Pearson coefficients were computed between the XR and INCL systems and between the XR and RAST systems. Reliability of each radiation-free system was excellent (ICC > 0.75 for INCL and RAST) for both the TK and LL parameters. The Pearson coefficients between each of the radiation-free systems and the XR were high to moderate for the TK (0.50 < RTK < 0.75 for INCL and RAST), high to moderate for the LL as measured with the RAST (0.50 < RLL < 0.75 for RAST) and low for the LL as measured with the INCL (RLL < 0.50 for INCL). This study demonstrated that for the RAST and INCL in AIS patients, there was (1) an excellent reliability for the TK and LL, (2) a high-to-moderate validity for measuring the TK and (3) a moderate and low validity for measuring the LL, respectively. These radiation-free systems could be used for the clinical follow-up of AIS patients for the evaluation of the TK. These slides can be retrieved under Electronic Supplementary Material.

Validity of a Smartphone Application (Sagittalmeter Pro) for the Measurement of Sagittal Balance Parameters

The study was aimed to compare the validity, reproducibility, precision, and efficiency of a picture archiving and communication system (PACS) and a smartphone application, which is an educative app to easily measure sagittal balance parameters (SagittalMeter Pro), for measuring spinopelvic sagittal parameters. Three spine surgeons measured lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), and pelvic tilt (PT) on standing posteroanterior radiographs of 30 patients using PACS and SagittalMeter Pro. Measurements were repeated a week after the original measurements. Intraobserver and interobserver variabilities and reliabilities of each parameter (LL, PI, SS, and PT) were calculated for both techniques. Comparisons were performed using the paired t-test. Results are expressed as mean ± standard deviation and P values of < 0.05 were considered significant. PACS to SagittalMeter Pro differences between the mean absolute values of LL, PI, SS, PT were 0.50°, 0.82°, 0.81°, 0.34°, respectively, and intraobserver and interobserver variabilities were similar. Excellent intraobserver and interobserver reliabilities were obtained for PACS and SagittalMeter Pro as demonstrated by values >0.86 and >0.84, respectively. Measurement times for PACS and SagittalMeter Pro were 36.63 ± 7.55 and 14.57 ± 1.96 seconds, respectively, and this difference was significant (P= 0.001). The study shows PACS and SagittalMeter Pro are equivalent in terms of their abilities to measure spinopelvic sagittal parameters, and that the time required to obtain measurements was significantly less for SagittalMeter Pro. We believe that SagittalMeter Pro may be helpful when planning spinal surgery.

Endoscopic posterior decompression under local anesthesia for degenerative lumbar spinal stenosis.

OBJECTIVEVarious minimally invasive techniques have been described for the decompression of lumbar spinal stenosis (LSS). However, few reports have described the results of endoscopic posterior decompression (EPD) with laminectomy performed under local anesthesia. This study aimed to evaluate the clinical and radiological outcomes of EPD performed under local anesthesia in patients with LSS and to compare the procedural outcomes in patients with and without preoperative spondylolisthesis.METHODSFifty patients (28 female and 22 male) who underwent EPD under local anesthesia were included in this study. Patients were assessed before surgery and were followed up with regular outpatient visits (at 1, 3, 6, 12, and 24 months postoperatively). Clinical outcomes were evaluated using the visual analog scale (VAS), Oswestry Disability Index (ODI), and the 36-Item Short Form Survey (SF-36) outcome questionnaire. Radiological outcomes were assessed by measuring lumbar lordosis, disc-wedging angle, percentage of vertebral slippage, and disc height index on plain standing radiographs.RESULTSThe VAS, ODI, and SF-36 scores were significantly improved at 1 month after surgery compared to the baseline mean values, and the improved scores were maintained over the 2-year follow-up period. Radiological progression was found in 2 patients during the follow-up period. Patients with and without preoperative spondylolisthesis had no significant differences in their clinical and radiological outcomes.CONCLUSIONSEPD performed under local anesthesia is effective for LSS treatment. Similar favorable outcomes can be obtained in patients with and without preoperative spondylolisthesis using this approach.

Saturday, September 29, 2018 10:30 am–12:00 pm Applying Deformity Concepts in Your Practice

BACKGROUND CONTEXT Recent studies have shown that lumbar fusion procedures are associated with an increased risk of total hip arthroplasty (THA) dislocation. Some authors have speculated that the increased risk of dislocation is caused by mispositioning of the acetabular component due to spinal sagittal imbalance. Unfortunately, the exact relationship between spinal sagittal balance and cup orientation is unknown. Furthermore, hip instability affected by cup orientation changes due to spinal sagittal imbalance remains unclear. PURPOSE To investigate the effect of spinal sagittal alignment on cup anteversion in THA dislocation. STUDY DESIGN/SETTING Retrospective cohort. PATIENT SAMPLE A total of 29 patients that suffered a THA dislocation and had lumbar radiographs prior to their THA. OUTCOME MEASURES Cup anteversion, lumbar lordosis, pelvic incidence, pelvic tilt, and sacral slope before THA. METHODS Patients that suffered a THA dislocation were retrospectively identified. Patients were included if they had lumbar radiographs prior to their THA. Patient characteristics were recorded including history of spinal fusion, surgical approach, primary or revision THA, direction of dislocation, and time from THA to dislocation. Cross-table lateral hip radiographs were used to measure cup anteversion with normal acetabular anteversion defined as 15°±10°. Lateral lumbar spine radiographs were used to measure lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS). Normal sagittal balance was defined as a PI-LL difference of RESULTS Twenty-nine patients had full radiographic imaging. Among these patients, 62.1% dislocated following a primary THA and 37.9% following a revision THA. Abnormal spinal sagittal balance was identified in 20 patients (69.0%). One-fourth (n=8, 27.6%) of patients had undergone spinal fusion prior to THA. Abnormal cup anteversion was demonstrated in 51.7% of all patients (7% with cup anteversion 25°). Presence of a spinal fusion was not associated with cup anteversion, sagittal balance or time to dislocation (p>.05 each). Sagittal balance was not associated with direction of dislocation, time to dislocation, or cup anteversion (p>.05 each). CONCLUSIONS A majority of patients with a THA dislocation demonstrated abnormal sagittal balance. However, sagittal balance was not associated with acetabular cup anteversion. As such, the relationship between spinal deformity and dislocation rates after THA may not be due to inaccurate cup orientation. More work is necessary to further delineate the influence of spinal alignment on THA stability. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Friday, September 28, 2018 10:30 AM–12:00 PM abstracts: deformity: technical factors: 165. Sagittal imbalance in degenerative scoliosis can be corrected by addressing only the symptomatic levels in carefully selected patients: a retrospective radiographic study

BACKGROUND CONTEXT The optimal method of addressing the positive sagittal imbalance often present in degenerative scoliosis (DS) is controversial. An important distinction is whether or not the etiology of the loss of lumbar lordosis (LL) and positive sagittal imbalance often seen on preoperative radiographs, is truly structural, or whether it is more positional in nature given that spinal stenosis is almost always present in DS patients who require surgery. This distinction directly affects the decision about whether or not, in addition to decompression, the entire curve needs to be addressed (regional or global fusion), or if a lesser local fusion of only the symptomatic levels can be performed with a satisfactory radiographic result. PURPOSE This study aims to determine (1) if the loss of LL often associated with DS is structural or rather largely due to positional factors secondary to spinal stenosis, and (2) if the entire DS curve or a lesser local fusion of only the neurologically symptomatic levels need to be addressed. STUDY DESIGN/SETTING Retrospective case series. PATIENT SAMPLE We obtained radiographic and clinical data on 114 consecutive patients. We included patients if they had loss of normal LL (positive sagittal imbalance) observed on preoperative radiographs and underwent a decompression and instrumented posterolateral inter-transverse process arthrodesis of only their neurologically symptomatic levels in the setting of DS. We excluded patients if they had undergone a previous fusion, concomitant osteotomy procedure, or any type of interbody arthrodesis, or had less than 6 months follow-up. Of the original 114 patients identified, 68 fulfilled the above criteria. OUTCOME MEASURES Pre- and postoperative radiographs were reviewed to measure lumbar lordosis, pelvic incidence, pelvic tilt, and sacral slope. Postoperative radiographs were also measured against preoperative extension lumbar radiographs and lumbar magnetic resonance imaging (MRI) to compare changes in radiographic pelvic parameters. METHODS Three independent members of the research team performed all measurements. Inter-rater reliability was calculated using a Pearson coefficient test and a strong correlation was considered if R>0.8. The three sets of measurements were then averaged for final statistical analysis. Relationships were considered significant at p RESULTS Average follow-up was 22 months. In addition to decompression, instrumented fusion was most commonly performed from L4 to S1 (N=17), followed by L3-S1 (N=12). The average PI found preop and postop was 52° and 53°, respectively. The average PT found preop and postop was 24° and 27°, respectively. Preoperative LL had a mean Cobb angle of 32° (range 2°–60°). Preop MRIs and lumbar extension radiographs revealed an average LL of 42° (range 10°–66°) and 48° (range 20°–74°), respectively. Initial postop radiographs (average 3 weeks) revealed that LL was corrected to a mean of 44° (range 14°–68°, p CONCLUSIONS We were able to correct LL to within 10° of the PI in this cohort of symptomatic DS patients with decompression and local instrumented fusion of symptomatic levels only. Loss of LL in symptomatic DS patients has a large positional component likely due to stenosis. Preoperative MRI and extension radiographs can be used to predict achievable postoperative LL correction.

Comparison of Four Radiographic Angular Measures of Lumbar Lordosis.

Background:Several attempts (radiographic and nonradiographic) have been made to measure the lumbar lordosis (LL), but the results differ substantially as investigators have used different parameters. Radiography is the gold standard, and the methods include lumbosacral angle (LSA), lumbosacral joint angle (LSJA), Cobb angle, and tangential radiologic assessment of LL (TRALL) angle. The traditional method, the Cobb technique, has a wide range of normal mean values, with a large standard deviation. Using a more reliable radiographic angle will hopefully simply and standardize LL measurement in the diagnosis, treatment, and follow-up of patients.Aim:To compare in normal individuals with fully developed LL the LSA, LSJA, TRALL, and Cobb angles, by determining (a) if any correlation exists between them and (b) the most reliable measures of LL, based on, least (i) number of measurement lines, (ii) range of values, (iii) mean, (iv) standard deviation, and (v) variance.Materials and Methods:The four angles were retrospectively measured in each supine lateral lumbosacral radiograph of 100 males and 100 females, aged 15 years and above. Data were analyzed with IBM SPSS Statistics 23.0 (NY, USA); P < 0.05 was considered statistically significant.Results:No correlation existed between the mean values of the four angles, and in each angle, there was no male-versus-female correlation. LSJA had the best reliability criteria for LL measurement.Conclusion:The mean LSA, LSJA, TRALL, and Cobb angles have no significant Pearson's correlation, and of the four angular measures of LL, LSJA was the most reliable.

Validation of prone intraoperative measurements of global spinal alignment.

OBJECTIVE Verifying the adequacy of surgical correction of adult spinal sagittal deformity (SSD) leads to improved postoperative alignment and clinical outcomes. Traditionally, surgeons relied on intraoperative measurements of lumbar lordosis (LL) correction. However, T-1 pelvic angle (TPA) and its component angles more reliably predict postoperative alignment. While TPA is readily measured on standing radiographs, intraoperative radiographs offer poor resolution of the bicoxofemoral axis. A method to recreate this radiographic landmark by extrapolating preoperative measurements has been described. The authors aimed to assess the reliability of measurements of global spinal alignment obtained via geometrical reconstitution of the bicoxofemoral axis on prone intraoperative radiographs. METHODS A retrospective review was performed. Twenty sets of preoperative standing full-length and intraoperative prone 36-inch lateral radiographs were analyzed. Pelvic incidence (PI) and sacral to bicoxofemoral axis distance (SBFD) were recorded on preoperative films. A perpendicular line was drawn on the intraoperative radiograph from the midpoint of the sacral endplate. This was used as one limb of the PI, and the second limb was digitally drawn at an angle that reproduced the preoperatively obtained PI, extending for a distance that matched the preoperative SBFD. This final point marked the obscured bicoxofemoral axis. These landmarks were used to measure the L-1, T-9, T-4, and T-1 pelvic angles (LPA, T9PA, T4PA, and TPA, respectively) and LL. Two spine fellows and 2 attending spine surgeons made independent measurements and repeated the process in 1 month. Mixed-model 2-way intraclass correlation coefficient (ICC) and Cronbach's α values were calculated to assess interobserver, intraobserver, and scale reliability. RESULTS Interobserver reliability was excellent for preoperative PI and intraoperative LPA, T9PA, and T4PA (ICC = 0.88, 0.84, 0.84, and 0.93, respectively), good for intraoperative TPA (ICC = 0.68), and fair for preoperative SBFD (ICC = 0.60) and intraoperative LL (ICC = 0.50). Cronbach's α was ≥ 0.80 for all measurements. Measuring PI on preoperative standing images had excellent intraobserver reliability for all raters (ICC = 0.89, range 0.80-0.93). All raters but one showed excellent reliability for measuring the SBFD. Reliability for measuring prone LL was good for all raters (ICC = 0.71, range 0.64-0.76). The LPA demonstrated good to excellent reliability for each rater (ICC = 0.76, range 0.65-0.81). The thoracic pelvic angles tended to be more reliable at more distal vertebrae (T9PA ICC = 0.71, range 0.49-0.81; T4PA ICC = 0.62, range 0.43-0.83; TPA ICC = 0.56, range 0.31-0.86). CONCLUSIONS Intraoperative assessment of global spinal alignment with TPA and component angles is more reliable than intraoperative measurements of LL. Reconstruction of preoperatively measured PI and SBFD on intraoperative radiographs effectively overcomes poor visualization of the bicoxofemoral axis. This method is easily adopted and produces accurate and reliable prone intraoperative measures of global spinal alignment.

Concurrent validity of photogrammetric and inclinometric techniques based on assessment of anteroposterior spinal curvatures

PurposeThe purpose of the study was to investigate correlations between parameters of anteroposterior spinal curvatures in the sagittal plane, measured with the use of photogrammetric technique and inclinometer in healthy elderly women.MethodsRandomized study involved 50 females, ranging from 50 to 70 years of age (mean 62.26 ± 6.94); mean body mass index (BMI) 27.69 ± 4.79. The examined parameters included angle of inclination in lumbosacral spine (ALFA), thoracolumbar transition (BETA), upper thoracic segment (GAMMA), angle of lumbar lordosis (LLA) and thoracic kyphosis (TKA). Results obtained with gravitational inclinometer were compared with those identified with photogrammetry method. Statistical analyses were performed with Mann–Whitney U test, regression analysis and Bland–Altman analysis.ResultsIn Mann–Whitney U test, with correction due to continuity, no statistically significant differences for any variable were found. Regression analysis was significant only for the variable of BETA angle. Bland–Altman coefficient for the respective angles was: ALFA 2.0%, BETA 4%, GAMMA 0%, LLA 2% and TKA 0%.ConclusionsThe results acquired with gravitational inclinometer and with photogrammetric technique are comparable, as the parameters of anteroposterior spinal curvatures acquired with these two methods are found to be compatible in the case of measurements of lumbar lordosis and thoracic kyphosis.

Radiological outcome of postoperative sagittal balance on standing radiographs in comparison to intraoperative radiographs in prone position when performing lumbar spinal fusion.

Aim of this study is to show the outcome of postoperatively measured lumbar lordosis in upright position in comparison to the intraoperatively estimated lumbar lordosis in prone position, as the lumbar lordosis is one of the most important factors for the clinical outcome after spinal fusion. Eighty-two patients, receiving lumbar fusion were included in this retrospective study. Intraoperative radiographs were scanned. Then radiographs of the whole spine pre- and postoperatively, as well as 1year after surgery were measured by a spine surgeon and a radiologist. The visible segment lordosis angles were measured and compared (L2-S1, L3-S1, L4-S1, L5-S1). In addition, the pelvic parameters pelvic incidence, pelvic tilt and sacral slope were measured pre- and postoperatively. The intraobserver reliability was almost perfect. The mean lordosis angle L4-S1 was 32.6°±7.8° intraoperatively and 29°±10.8° postoperatively. A linear correlation of these two measurements can be seen. In mean, the postoperative lordosis is 4° smaller than intraoperatively. This trend can also be seen in the level L3-S1. In levels L2-S1 and L5-S1 the postoperative values were slightly higher than intraoperatively, but without any significance. Also, 1year after surgery there were no significant changes in global lumbar lordosis. Measuring lordosis angles intraoperatively resulted in almost the same values as measurements in standing plane radiographs postoperatively, despite prone position. These findings could especially be shown for the level L4-S1. The intraobserver reliability was almost perfect for both, intra- and postoperative measurements. In conclusion, the intraoperative measurement of a lumbar lordosis angle can perfectly predict the postoperative result.

Association Between Vertebral Cross-sectional Area and Vertebral Wedging in Children and Adolescents: A Cross-sectional Analysis

A small vertebral cross-sectional area (CSA) imparts a mechanical disadvantage that escalates the risk for vertebral fractures in elderly populations. We examined whether a small vertebral CSA is also associated with a greater degree of vertebral wedging in children. Measurements of vertebral CSA, lumbar lordosis (LL) or thoracic scoliosis angle, and vertebral wedging were obtained in 100 healthy adolescents (50 boys and 50 girls) and 25 girls with adolescent idiopathic scoliosis (AIS) using magnetic resonance imaging. Vertebral CSA of the lumbar vertebrae negatively correlated to the degree of posteroanterior vertebral wedging at L5 (r = -0.49; p < 0.0001); this was true whether all subjects were analyzed together or boys and girls independently. In contrast, we found a positive correlation between the degree of LL and vertebral wedging (r = 0.57; p < 0.0001). Multiple regression analysis showed that the association between vertebral CSA and wedging was independent of age and body mass index. In girls with AIS, vertebral CSA negatively correlated to the degree of lateral thoracic vertebral wedging (r = -0.66; p = 0.0004), an association that persisted even after accounting for age and body mass index. Additionally, Cobb angle positively correlated to lateral thoracic vertebral wedging (r = 0.46; p = 0.021). Our cross-sectional results support the hypothesis that smaller vertebral CSA is associated with greater vertebral deformity during growth, as in adulthood. © 2017 American Society for Bone and Mineral Research.

The effect of prophylactic vertebroplasty on the incidence of proximal junctional kyphosis and proximal junctional failure following posterior spinal fusion in adult spinal deformity: a 5-year follow-up study

Background ContextThe incidence of proximal junctional kyphosis (PJK) ranges from 5% to 46% following adult spinal deformity surgery. Approximately 66% to 76% of PJK occurs within 3 months of surgery. A subset of these patients, reportedly 26% to 47%, develop proximal junctional failure (PJF) within 6 months postoperatively. To date, there are no studies evaluating the impact of prophylactic vertebroplasty on PJK and PJF incidence at long-term follow-up. PurposeThe purpose of this study is to evaluate the long-term radiographic and clinical outcomes, and incidence of PJK and PJF, after prophylactic vertebroplasty for long-segment thoracolumbar posterior spinal fusion (PSF). Study DesignThis is a prospective cohort study. Patient SampleThirty-nine patients, of whom 87% were female, who underwent two-level prophylactic vertebroplasty at the upper instrumented and supra-adjacent vertebrae at the time of index PSF were included in this study. Outcome MeasuresClinical outcomes were assessed using the Scoliosis Research Society-22 (SRS-22), and Short-Form (SF) 36 questionnaires, and the Oswestry Disability Index (ODI). Radiographic parameters including PJK angle, and coronal and sagittal alignment, were calculated, along with relevant perioperative complications and revision rates. MethodsOf the 41 patients who received two-level prophylactic vertebroplasty at the upper instrumented and supra-adjacent vertebrae at the time of index PSF, and comprised a cohort with previously published 2-year follow-up data, 39 (95%) completed 5-year follow-up (average: 67.6 months). Proximal junctional kyphosis was defined as a change in the PJK angle ≥10° between the immediate postoperative and final follow-up radiograph. Proximal junctional failure was defined as acute proximal junctional fracture, fixation failure, or kyphosis requiring extension of fusion within the first 6 months postoperatively. ResultsThirty-nine patients with a mean age of 65.6 (41–87) years were included in this study. Of the 39 patients, 28.2% developed PJK (11: 7.7% at 2 years, 20.5% between 2 and 5 years), and 5.1% developed acute PJF. Two of the 11 PJK patients required revision for progressive worsening of the PJK. There were no proximal junctional fractures. There was no significant difference in preoperative, immediate postoperative, and final follow-up measurements of thoracic kyphosis, lumbar lordosis, and coronal or sagittal alignment between patients who developed PJK, PJF, or neither (p>.05). There was no significant difference in ODI, SRS-22, or SF-36 scores between those with and without PJK or PJF (p>.05). ConclusionsThis long-term follow-up demonstrates that prophylactic vertebroplasty may minimize the risk for junctional failure in the early postoperative period. However, it does not appear to decrease the incidence of PJK at 5 years.

Chronic low back pain after lumbosacral fracture due to sagittal and frontal vertebral imbalance

Problem and hypothesisOver time, some patients with unilateral or bilateral lumbosacral injuries experience chronic low back pain. We studied the sagittal and frontal balance in a population with these injuries to determine whether mismatch in the pelvic and lumbar angles are associated with chronic low back pain. Patients and methodsPatients with posterior pelvic ring fractures (Tile C1, C2, C3 and A3.3) that had healed were included. Foreign patients and those with an associated spinal or acetabular fracture or nonunion were excluded. The review consisted of subjective questionnaires, a clinical examination, and standing A/P and lateral stereoradiographic views. The pelvic tilt (PT), sacral slope (SS), pelvic incidence (PI), measured lumbar lordosis (LLm), T9 sagittal offset, leg discrepancy (LD) and lateral curvature (LC). The expected lumbar lordosis (LLe) was calculated using the formula LLe=PI+9°. We defined lumbopelvic mismatch (LPM) as the difference between LLm and LLe being equal or greater than 25% of LLe. ResultsFifteen patients were reviewed after an average follow-up of 8.8 years [5.4–15]. There were four Tile C1, five Tile C2, five Tile C3 and one Tile A3.3 fracture. Ten of the 15 patients had low back pain. The mean angles were: LLm 49.6° and LLe 71.9° (P=0.002), PT 21.3°, SS 44.1°, PI 62.9° in patients with low back pain and LLm 57.4° and LLe 63.2° (P=0.55), PT 13°, SS 43.1°, PI 54.2° in those without. LPM was present in 9 patients, 8 of who had low back pain (P=0.02). Six patients, all of whom had low back pain, had a mean LC of 7.5° [4.5–23] (P=0.02). The mean LD was 0.77cm. DiscussionThe findings of this small study suggest that patients who experience low back pain after their posterior arch of the pelvic ring fracture has healed, have a lumbopelvic mismatch. Early treatment of these patients should aim to reestablish the anatomy of the pelvic base relative to the frontal and sagittal balance. Level of evidenceIV.

The impact of office chair features on lumbar lordosis, intervertebral joint and sacral tilt angles: a radiographic assessment

Background: The purpose of this study was to determine which office chair feature is better at improving spine posture in sitting. Method: Participants (n = 28) were radiographed in standing, maximum flexion and seated in four chair conditions: control, lumbar support, seat pan tilt and backrest with scapular relief. Measures of lumbar lordosis, intervertebral joint angles and sacral tilt were compared between conditions and sex. Results: Sitting consisted of approximately 70% of maximum range of spine flexion. No differences in lumbar flexion were found between the chair features or control. Significantly more anterior pelvic rotation was found with the lumbar support (p = 0.0028) and seat pan tilt (p < 0.0001). Males had significantly more anterior pelvic rotation and extended intervertebral joint angles through L1–L3 in all conditions (p < 0.0001). Conclusion: No one feature was statistically superior with respect to minimising spine flexion, however, seat pan tilt resulted in significantly improved pelvic posture.Practitioner Summary: Seat pan tilt, and to some extent lumbar supports, appear to improve seated postures. However, sitting, regardless of chair features used, still involves near end range flexion of the spine. This will increase stresses to the spine and could be a potential injury generator during prolonged seated exposures.

How consistent are lordosis, range of movement and lumbo-pelvic rhythm in people with and without back pain?

BackgroundComparing movements/postures in people with and without lower back pain (LBP) may assist identifying LBP-specific dysfunction and its relationship to pain or activity limitation. This study compared the consistency in lumbo-pelvic posture and movement (range and pattern) in people with and without chronic LBP (>12 week’s duration).MethodsWireless, wearable, inertial measurement units measured lumbar lordosis angle, range of movement (ROM) and lumbo-pelvic rhythm in adults (n = 63). Measurements were taken on three separate occasions: two tests on the same day with different raters and a third (intra-rater) test one to two weeks later. Participants performed five repetitions of tested postures or movements. Test data were captured automatically. Minimal detectable change scores (MDC90) provided estimates of between-test consistency.ResultsThere was no significant difference between participants with and without LBP for lordosis angle. There were significant differences for pelvic flexion ROM (LBP 60.8°, NoLBP 54.8°, F(1,63) = 4.31, p = 0.04), lumbar right lateral flexion ROM (LBP 22.2°, NoLBP 24.6° F(1,63) = 4.48, p = .04), trunk right lateral flexion ROM (LBP 28.4°, NoLBP 31.7°, F(1,63) = 5.9, p = .02) and lumbar contribution to lumbo-pelvic rhythm in the LBP group (LBP 45.8 %, F(1,63) = 4.20, NoLBP 51.3 % p = .044). MDC90 estimates for intra and inter-rater comparisons were 10°–15° for lumbar lordosis, and 5°–15° for most ROM. For lumbo-pelvic rhythm, we found 8–15 % variation in lumbar contribution to flexion and lateral flexion and 36–56 % variation in extension. Good to excellent agreement (reliability) was seen between raters (mean r = .88, ICC (2,2)).ConclusionComparisons of ROM between people with and without LBP showed few differences between groups, with reduced relative lumbar contribution to trunk flexion. There was no difference between groups for lordosis. Wide, within-group differences were seen for both groups for ROM and lordosis. Due to variability between test occasions, changes would need to exceed 10°–15° for lumbar lordosis, 5°–15° for ROM components, and 8–15 % of lumbar contribution to lumbo-pelvic rhythm, to have 90 % confidence that movements had actually changed. Lordosis, range of movement and lumbo-pelvic rhythm typically demonstrate variability between same-day and different-day tests. This variability needs to be considered when interpreting posture and movement changes.Electronic supplementary materialThe online version of this article (doi:10.1186/s12891-016-1250-1) contains supplementary material, which is available to authorized users.

Preoperative, Intraoperative, and Postoperative Standing Lordosis After Pedicle Subtraction Osteotomy: An Analysis of Radiographic Parameters and Surgical Strategy

Study DesignRetrospective consecutive case series. ObjectivesThe objective of this study was to investigate the relationship between intraoperative and postoperative lumbar spine measurements after pedicle subtraction osteotomy (PSO). We analyzed the amount of lordosis lost between the prone intraoperative image and the final upright standing film. The outcome of this analysis should be used in preoperative planning for osteotomy procedures. MethodsSixteen patients had pre-, intra- and postoperative measurements of lumbar lordosis. Pre- and postoperative measures of pelvic parameters were also determined. Comparisons were made between pre-, intra- and postoperative measures of pelvic parameters, with specific attention to lumbar lordosis correction and the loss of correction with transition to a standing position. ResultsThe average pelvic mismatch between preoperative lumbar lordosis and pelvic incidence was 37 degrees whereas the postoperative mismatch measured 3.2 degrees. All patients had a significant correction of their lumbar lordosis. The lumbar lordosis showed a highly significant loss of 12.5 degrees from the intraoperative prone position to the postoperative standing position, with the average lumbar lordosis intraoperatively (67 degrees) decreasing to a standing lumbar lordosis of 54 degrees (p < .000001). ConclusionsThis analysis should aid in preoperative planning for sagittal global alignment correction and can reduce the chance of over- or under-correction in patients having a PSO procedure. Given the narrow postoperative target that is associated with better outcomes for patients, the loss of lumbar lordosis from prone to standing position may be a crucial variable in this planning process.