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Adequate sagittal balance (SB) is essential to maintain an upright, efficient, and painless posture. It has been shown that sagittal profile alterations affect quality of life of patients with a similar or even greater impact than chronic disease. Evaluation of the SB has gained much relevance in recent years, with recognition of its importance in the evaluation of spinal pathology. This review summarizes the basic principles of SB, aiming to obtain a practical, simple and understandable evaluation of the sagittal profile of a patient. SB is a dynamic process that involves a varying degree of energy expenditure. Distinguishing between a balanced, compensated imbalance or decompensated imbalanced patient, is relevant to diagnosis and therapeutic decision-making. Cite this article: EFORT Open Rev 2021;6:1193-1202. DOI: 10.1302/2058-5241.6.210062

Introduction: Preoperative factors that predict postoperative restoration of lumbar lordosis (LL) are not well understood. To investigate whether preoperative postural correction of LL, sagittal malalignment, or lumbar flexibility are associated with the postoperative restoration of LL in patients treated with a single-level transforaminal lumbar interbody fusion (TLIF), a retrospective cohort study was conducted. Methods: We enrolled 104 patients (mean age: 67.5±10.7 years old; 47 men and 57 women) with lumbar degenerative diseases treated with a single-level TLIF. The pre- and postoperative LL were examined using lateral radiographs in the standing position and computed tomography (CT) images in the supine position. The correlation between postoperative LL restoration and preoperative postural correction of LL (difference in LL between the standing and supine positions: D-LL), sagittal imbalance (pelvic incidence minus LL: PI-LL), and lumbar flexibility (difference in LL between the flexion and extension postures) were analyzed. Patients were divided into two groups according to the D-LL (D-LL0° and D-LL

To develop a decision-making pathway for primary SA-LLIF. Furthermore, we analyzed the agreement of this pathway and compared outcomes of patients undergoing either SA-LLIF or 360-LLIF. A decision-making pathway for SA-LLIF was created based on the results of interviews/surveys of senior spine surgeons with over 10 years of experience. Internal validity was retrospectively evaluated using consecutive patients undergoing either SA-LLIF or 360-LLIF between 01/2018 and 07/2020 with 3D-printed Titanium cages. An outcome assessment looking primarily at revision surgery and secondary at cage subsidence, changes in disk and foraminal height, global and segmental lumbar lordosis, duration of surgery, estimated blood loss, and length of stay was carried out. 78 patients with 124 treated levels (37 SA-LLIF, 41 360-LLIF) were retrospectively analyzed. The pathway showed a direct agreement (SA-LLIF) of 100.0% and an indirect agreement (360-LLIF) of 95.1%. Clinical follow-up averaged 13.5 ± 6.5 months including 4 revision surgeries in the 360-LLIF group and none in the SA-LLIF group (p = 0.117). Radiographic follow-up averaged 9.5 ± 4.3 months, with no statistically significant difference in cage subsidence rate between the groups (p = 0.440). Compared to preoperative images, patients in both groups showed statistically significant changes in disk height (p

Aim of this study was to analyze the rate of tether breakages after lumbar vertebral body tethering (VBT) and to study the effects and possible benefits of the use of a 2-tether construct. Tether breakage is a known mechanical complication after VBT. However, the literature only refers to thoracic VBT, and no data on the breakage rate or 2-tether construct after lumbar VBT are available. Patients who underwent lumbar VBT with lowest instrumented vertebra at L3 or L4 and had a 1-year follow-up were included. Radiologic data were obtained preoperatively, at the 1st standing X-ray and at the 1-year follow-up to study breakage rate, loss of correction and lumbar lordosis in 1- and 2-tether constructs. Data from 30 patients (mean age 14.7 ± 1.8) were available, 12 with double tether. Double tether did not decrease lumbar lordosis. The breakage rate was 24% in segments instrumented with a single tether and 16% in segments instrumented with a double tether (OR 1.6, p = 0.4). Lumbar loss of correction was 10° ± 6.8° in the entire cohort and 12.1° ± 5.4° in patients with a breakage (p = 0.2). Revision rate was 10%, due to tether breakage and loss of correction. Breakage rate after lumbar VBT is high, but was improved with the use of a 2-tether construct. Despite tether breakage, loss of correction was limited and the revision rate low. The use of a double tether does not have a kyphotic effect on the lumbar spine.

OBJECTIVE: The purpose of this study was to investigate differences in regional lumbar lordosis (RLL) and global lumbar lordosis (GLL) angle during slumped sitting and upright sitting among three global subgroups. METHODS: A total of 48 young asymptomatic volunteers stood in a comfortable posture, sat upright, and sat in a slumped position for 5 seconds, with inertial measurement units attached to the T10, L3, and S2 vertebrae. According to standing measurement, the participants were categorized into flat-back (GLL < 20∘), normal lordosis (20∘⩽ GLL < 30∘), and hyper-lordosis (30∘⩽ GLL < 40∘) groups. RESULTS: Both the GLL and RLL in the flat-back group were reduced lumbar lordosis in the upright sitting posture and increased lumbar kyphosis in the slumped sitting postures compared to the other groups (p< 0.05), but the range of motion during the transition from upright sitting to slumped sitting was lower than that of the normal and hyper-lordosis groups (p< 0.05). GLL in standing was a moderate correlation with GLL and RLL during upright sitting (p< 0.05). However, there was a strong correlation between GLL and RLL kinematics during upright and slumped sitting (p< 0.05). CONCLUSIONS: Flat-back posture is a potential source of low back pain during both upright and slumped sitting compared to the normal and hyper-lordosis groups. Posture measurements in a standing and sitting position conducted to assess lordosis should consider the relationship between GLL and RLL.

Introduction The impact of lumbar spinal fusion (LSF) on pelvic mobility and increased risk for THA dislocation are recognized. However, there is still controversy on whether THA should be performed prior or following LSF. This study aims to compare the rates of hip dislocation in patients undergoing THA prior to or following LSF. Methods We retrospectively reviewed 109 primary THA and LSF. There were 34 men and 75 women with a mean age of 66.9. The cohort was divided into 2 groups: 1) THA prior to lumbar fusion (n = 42) and 2) THA following lumbar fusion (n = 67). Radiographic parameters including acetabular component abduction, anteversion, pelvic incidence (PI), sacral slope, standing lumbar lordosis (LL) and PI-LL mismatch were determined for each patient. The surgical approach and THA parameters were also recorded and compared between the 2 groups. Patients with fracture, malignant disease, and prior hip hardware were excluded. Results The mean follow up was 14.7 months. Overall, 8 patients (7.3%) had a postoperative hip dislocation (0 in group 1 (0%), and 8 in group 2 (11.9%) (p = 0.022). The mean cup abduction and anteversion in patients that dislocated was 37.7° and 23.4° respectively while patients who did not dislocate had an average cup abduction of 37.6° (p = 0.970) and anteversion of 25.9° (p = 0.367). Patients who dislocated had decreased lumbar lordosis (p = 0.022) and higher PI-LL mismatch (p = 0.0004) compared to that did not dislocate. There were no other significant differences in the spinopelvic parameters between the 2 groups. Neither surgical approach nor dual mobility articulations use had a significant impact on postoperative dislocations. Conclusion Higher rates of hip dislocation were observed in patients undergoing primary THA following LSF. Dislocators had decreased lumbar lordosis and increased PI-LL mismatch. Patients who require both spinal fusion and THA should undergo hip arthroplasty first to minimize the risk of postoperative instability.

Objective To assess the effect that correction of lower lumbar lordosis (3L) has on global spine realignment due to the key role of 3L for scoliosis surgery in patients with degenerative lumbar scoliosis (DLS). Methods This study is a retrospective review performed between June 2018 and January 2020, including consecutive patients with DLS. Only patients age ≥ 45 years who had already undergone a selective root block operation and had the procedure of long‐fusion extending to pelvis and posterior lumbar interbody fusion (PLIF) at lower lumbar spine (L4‐S1) were retained for analysis. Spinopelvic parameters measured included thoracic kyphosis (TK), lumbar lordosis (LL), 3L, pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), T1 pelvic angle (TPA), and sagittal vertical axis (SVA) at pre‐operation and the third month follow‐up. The mismatch (PI‐LL) was calculated subsequently. Pearson correlation and linear regression analysis were performed to explore the association of the changes in global spinopelvic parameters with 3L correction. Results Thirty‐nine patients (five males, 34 females) with the average age of 63.84 years (SD 7.53; range, 45–75 years) at the time of surgery were identified. All patients had the surgical procedure of long‐fusion (≥4 vertebras) with PLIF at lower lumbar spine between L4 and S1 spine. Lower instrumented vertebras (LIV) fused to pelvis (S1, 14; S2, 18; ilium, 7) were operated in all patients. Seventeen patients were with upper instrumented vertebras (UIV) at thoracolumbar spine (L2‐T11), and 22 patients at thoracic spine (T10 and above). The median of instrumented segments was 10 (5–14). 3L significantly increased (P = 0.02) after surgical treatment by mean change of 4.21° (range, −19.7° to +22.2°). Perioperatively, all spinopelvic parameters regarding to TK, LL, SS, PT, TPA, SVA, and mismatch (PI‐LL) had significant changes (P, Scatterplots showing the change in lumbar lordosis correlated with changes in spinopelvic parameters. The linear regression formulas are as follows: d‐LL = 14.977+ 0.636*d‐3L, (R 2 = 0.596); d‐(PI‐LL) = 16.575 + 0.62*d‐3L, (R 2 = 0.183); d‐TPA = −7.284 to 0.358*d‐3L, (R 2 = 0.193); d‐SVA = −30.556 to 2.639*d‐3L, (R 2 = 0.347).

BACKGROUND: Few studies directly compare the effect of interbody cages with different degrees of lordosis in producing segmental lumbar lordosis (SLL) in the transforaminal lumbar interbody fusion (TLIF) procedure. Thus, we aimed to investigate changes in SLL in hyperlordotic cages compared to standard lordotic cages in open TLIF procedures. METHODS: Thirty-eight consecutive patients who received open TLIF procedures performed by a single surgeon between 2017 and 2018 were reviewed. Twenty patients had “hyperlordotic cages” (20° lordosis), while 18 patients had “standard lordotic cages” (6° lordosis). Twenty-three patients had one-level TLIF procedures and 15 had two-level TLIF. Standard radiographic measurements, including SLL were assessed preoperatively, postoperatively, and at 1-year follow-up. SLL was measured from the superior endplate of the cephalad vertebra to the inferior endplate of the caudal vertebra. Changes in SLL were compared using Student’s and paired t-tests. RESULTS: In one- and two-level open TLIF, both hyperlordotic and standard lordotic cages produced significant improvement in SLL. Among those receiving a one-level TLIF, SLL increased 7.8° (P=0.024) in those with standard lordotic cages; it increased 8.2° (P=0.020) in those with hyperlordotic cages. Among those receiving a two-level TLIF, SLL increased 13.9° (P=0.032) in those with standard lordotic cages; it increased 8.8° (P=0.023) in those with hyperlordotic cages. However, the improvement in SLL was not significantly different between the two cage types in either one or two-level TLIF procedures (P=0.917, P=0.389). At 1-year follow-up, there was no significant change in SLL, among standard lordotic and hyperlordotic cages (P=0.501, P=0.781). CONCLUSIONS: Although it is theorized that hyperlordotic cages would increase SLL during open TLIF procedures more than standard lordotic cages, our data failed to demonstrate that. As our study examined cases performed by a single surgeon immediately before and after adoption of these lordotic cages, it is likely that surgical technique is of equal or greater importance in improving SLL than the amount of lordosis designed into interbody cages.

To explore the normal distribution of cervical sagittal alignment and the relationship between cervical alignment and global spine balance in asymptomatic young adults. A total of 67 males and 59 females aged from 18 to 30 years old were recruited from 11/2011 to 12/2014. The C0-C2 angle, disk angles from C2-C3 to C6-C7, vertebral angles from C3 to C7, T1 slope, thoracic kyphosis (TK), lumbar lordosis, pelvic incidence, sacral slope, C2-C7 sagittal vertical axis (SVA), center of gravity of head to C7 SVA (CGH-C7SVA), C7-S1SVA were measured and statistically analyzed. The Roussouly classification was utilized. Mean value of C0-C7 was 26.0° ± 12.8°, composed of 15.2° ± 6.7° for C0-C2, 9.1° ± 12.1° for sum of disk angles from C2-C3 to C6-C7, and 1.4° ± 10.2° for sum of vertebral angles from C3 to C7. C2-C7SVA (18.6 mm ± 7.9 mm) and CGH-C7SVA (22.9 mm ± 12.3 mm) were offset ideally by C7-S1SVA (-21.6 mm ± 31.0 mm). Significant difference was found between cervical alignment of different Roussouly types (p

Previous studies only investigated the simple linear relationships of global tilt (GT) with thoracic kyphosis (TK), lumbar lordosis (LL) and pelvic incidence (PI). This study aimed to establish multiple linear regressions of GT based on individual TK, LL and PI in patients with degenerative spines. Four hundred sixty-nine adult patients aged older than 35 years with various degenerative spinal diseases were enrolled in this two-centre study between January 2017 and December 2020. Full-spine X-rays were performed for all the subjects in a standing position. The following regional and global parameters were measured in the sagittal plane: TK, LL, PI, pelvic tilt (PT), sagittal vertical axis (SVA) and GT. The correlations of the GT, PT and SVA with the TK, LL and PI were analysed, and then multiple linear regressions were constructed. GT was statistically correlated with TK, LL and PI. Additionally, TK, LL and PI were significant predictors for the GT, PT and SVA models. The relevant predictive formulae were as follows: GT = -9.60 + 1.09*PI + 0.89*LL + 0.42*TK (R2 = 0.935), PT = -4.49 + 0.81*PI + 0.56*LL + 0.24*TK (R2 = 0.792) and SVA = -25.68 + 2.98*LL + 2.37*PI + 1.67*TK (R2 = 0.416). The specific sagittal spinopelvic morphology, evaluated by GT parameters, should be determined by individual TK, LL and PI values in the degenerative spine. Surgeons can utilize such predictive models to better understand the degenerative evolution of sagittal alignment and recognize the relationships between regional parameters and global sagittal alignment to customize a precise correction strategy.

Introduction Previous studies have reported differences in lumbopelvic alignment between standing and supine positions. Computed tomography (CT) images taken in the supine position are often used for clinical studies in addition to standing radiographs, although not frequently. Our study aims to clarify normative values of CT-evaluated lumbopelvic parameters and the characteristics of age- and gender-related lumbopelvic alignment in the supine position. Methods Patients undergoing CT scans of abdominal or lumbar regions for reasons other than low back disorders were included (n=581). Sagittal multiplanar reconstruction CT images were obtained, and lumbar lordosis (LL), L5-S1 angle, and sacral slope (SS) were measured. Mean values of the parameters in patients aged 59 years and under, 60-69, 70-79, and 80 and over, and in males and females, were calculated. Age- and gender-related differences in these parameters were statistically analyzed. Results Among the four age groups, patients 80 years and over showed significantly lower LL and SS than patients aged 70-79. Females 80 years and over showed significantly lower LL and SS than all other age groups, but those in males did not. The comparison between males and females showed no significant differences in LL and SS; however, the L5-S1 angle was significantly higher in males than in females. In patients 80 years and over, females showed significantly lower LL and SS than in males. Conclusions This study provides normative CT-evaluated lumbopelvic parameters, such as LL, L5-S1 angle, and SS, which will be utilized for comparisons in future studies. The present study first revealed that pelvic retroversion and lumbar kyphosis occur in elderly females in the supine position, which raised a possibility that age-related decrease of LL and SS in females occurs at an older age in the supine position than in the standing position.

There is a paucity of data describing sagittal alignment changes in children with congenital scoliosis (CS) treated by hemivertebra (HV) resection. This study aimed to evaluate the effects of posterior HV resection on spine sagittal alignment in children with CS. This is a retrospective analysis of 31 children with CS (mean age at surgery: 49.61 ± 10.21 months; range, 39-72; mean follow-up time: 5.16 ± 1.21 years; range: 3-7) treated at our Institution. Only patients with single thoracic or single lumbar, fully segmented HV managed by posterior HV resection and two segments fusion with four screws and two robs were included. According to the anatomical location of the HV, patients were divided into two groups: thoracic (group A) and lumbar (group B). Thoracic kyphosis (T1-T12; TK) and lumbar lordosis (L1-S1; LL) were measured pre- and postoperatively at 6 months interval. Postoperative TK and LL were 30.3 ± 11.47 and 28.8 ± 9.47, and were 31.98 ± 9.66 and 46.7 ± 11.37 at the last follow-up visit, respectively. The incidence of thoracic hypokyphosis in group B was 53.3%, and it was significantly higher compared to group A (12.5%, P = 0.04). During follow-up, TK changes were comparable between the two groups of patients while LL improved in all patients 6 months after surgery, and continued to improve thereafter. Posterior HV resection and short segment fusion have limited impact on the evolution of TK; in particular, children with lumbar HV were more likely to be hypokyphotic preoperatively, but less likely postoperatively with an increase in LL and a stabilization of TK.

Introduction: Recent research has shown that spinal sagittal alignment plays a critical role in health-related quality of life. However, most of these studies were cross-sectional in nature, and longitudinal studies of lumbar lordosis (LL) in healthy subjects were few. This study aims to evaluate the change in lumbar sagittal parameters during a 10-year period. Methods: The study population included 45 individuals (mean age, 65.7 years; male, n=20; female, n=25) who underwent sagittal lumbar radiography and a basic health checkup during a 10-year period. The radiologic parameters were LL, disc angle, sacral slope angle (SS), and pelvic incidence (PI). The change of LL during the 10-year period was defined as ΔLL. The subjects were divided into the LL maintenance group (n=33) and the LL non-maintenance group (n=12) based on their LL values. Results: The radiologic baseline/final parameters were as follows: LL, 45/34 degrees (P

Study Design. A retrospective study. Objectives. The purpose of this study was to evaluate optimal and ideal target values of the spine balance correction in elderly patients with adult spinal deformity who were over the age of 60 years. Summary of Background Data. The target values of the Scoliosis Research Society -Schwab classification to obtain satisfactory alignment and favorable outcomes are used in many spinal reconstruction surgeries. However, uniformly applying the Scoliosis Research Society-Schwab classification to all elderly patients aged 60 years or older showing sagittal malalignment may lead to several inconsistencies. Methods. This study included 121 patients (average age 70.5 yr and a minimum 2-yr follow-up) with adult spinal deformity who underwent long-segment fusion from T10 to sacrum. We used Pearson's correlation coefficient to analyze the relationship between clinical and radiographic parameters, and multilinear regression analysis and multivariate logistic regression model (backward elimination method) were conducted using the correlation factors of postoperative (Post) and last follow-up (Last) sagittal vertical axis to find the risk factors of Post sagittal imbalance. Results. Logistic regression analysis with the correlation factors of Post and Last sagittal vertical axis led to risk factors of Post sagittal imbalance, and after confirming the significance of each path, it was confirmed that the effects of pelvic incidence (PI)— lumbar lordosis (LL) and Post pelvic tilt ratio (PTr) were valid (P

To study factors causing postoperative change of PI after surgical correction of ASD and to assess the effect of this variability on postoperative PI-LL mismatch. PI is used as an individual constant to define lumbar lordosis (LL) correction goal (PI-LL 10°) associated with a |∆PI|> 6°, P = 0.05. Sacroiliac fixation diminished PI variability only during the first postoperative year. Preoperative variability and postoperative instability of PI diminish the applicability of the PI–LL

Objective. To analyze the significance of the influence of various risk factors on the development of proximal junctional kyphosis (PJK) and instability of instrumentation.Material and Methods. The results of surgical treatment of 382 patients with scoliotic deformities of the lumbar spine of type I and IIIb according to Aebi were analyzed. Patients were operated on through the posterior approach using the TLIF-PLIF technique with extended rigid transpedicular instrumentation. Potential risk factors influencing the development of proximal junctional kyphosis and instability of instrumentation were analyzed.Results. It was found that only three risk factors significantly affect the development of PJK: correction of lumbar lordosis more than 30° (p = 0.036) increases the likelihood of its development by 1.5 times, osteoporosis (p = 0.001) – by 2.5 times, and proximal junctionalangle ≥10° (p = 0.001) – by 3.5 times. Three factors showed a statistically significant effect on the incidence of instrumentation instability: correction of lumbar lordosis more than 30° (p = 0.034) increases the likelihood of its occurrence by 1.7 times, osteoporosis (p = 0.018) – by 1.8 times, and deviation of the sagittal vertical axis by more than 50 mm (p = 0.001) – by 3.3 times.Conclusion. The most significant risk factors for the occurrence of PJK and instability of instrumentation are osteoporosis, correction of lumbar lordosis more than 30°, an increase in the proximal junctional angle ≥10°, and an anterior deviation of sagittal vertical axis more than 50 mm. Consideration of these factors in the preoperative period, as well as during surgery, can decrease likelihood of the occurrence of PJK and instability of instrumentation.

Study design Retrospective observational study. Objective To assess the accuracy and reliability of standing lateral lumbar radiographs for measurements of spinopelvic parameters, compared with whole-spine EOS® images. Summary of background data Lateral lumbar radiographs are commonly used for measurements of spinopelvic parameters. However, variable magnifications by fan-beam x-ray projection at margins may cause measurement errors. Methods Fifty consecutive patients with standing lateral lumbar radiographs and whole-spine EOS® images were retrospectively reviewed from March to July in 2019. Two orthopedic surgeons (observers) independently measured the spinopelvic parameters including pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), and lumbar lordosis (LL) on the computers. These spinopelvic parameters of each patient were measured twice on both lateral lumbar radiograph and EOS® image by two observers with the usage of Surgimap software. The measurement difference and agreement of each parameter value between lateral lumbar radiographs and EOS® images were analyzed by paired t test and the interclass correlation coefficient (ICC) respectively. Intra- and inter-observer's reliabilities of both imaging methods were assessed by ICC. Results The measurement difference of each spinopelvic parameter on EOS® images and lateral lumbar radiographs was less than 1° on average. Only the measurement difference of PI value revealed statistically significant (P = 0.020) with 0.9° discrepancy (95% confidential interval: 0.2-1.6), which indicated no clinical significance. The ICC values of lateral lumbar radiographs and EOS® images were more than 0.870 (range, 0.872-0.976), thus showed good to excellent measurement agreement between both imaging methods. All the ICC values for evaluating intra- and inter-observer reliability were greater than 0.960 (range, 0.963-0.993), indicating excellent reliability for observer's measurements. Conclusion Measurements of spinopelvic parameters (PI, PT, SS, and LL) on standing lateral lumbar radiographs are accurate and reliable, which are comparable to whole-spine EOS® images.Level of Evidence: 3.

Divi SN, Kepler CK, Hilibrand AS, et al. Patient Outcomes Following Short-segment Lumbar Fusion Are Not Affected by PI-LL Mismatch. Clin Spine Surg. Mar 1 2021;34(2):73-77., Visual AbstractThis is a visual representation of the abstract.

BACKGROUND: The aim of this study was to determine the contribution of individual vertebral body lordosis to lumbar lordosis and establish the relationship of vertebral body lordosis to the pelvic incidence (PI). METHODS: One-hundred and two computed tomography (CT) scans on patients free of radiographic disease were measured for PI and segmental lordosis of both bone and disc from L1 to sacrum. Correlative analysis and analysis of variance (ANOVA) were used to identify contribution from bone and disc to lordosis. RESULTS: The mean total bony lordosis was 10.8° (SD 11.5°), mean total disc lordosis was 36.3° (SD 9.9°), and mean combined lordosis was 47.1° (SD 10.0°). The mean PI of the entire cohort was 49.2° (SD 9.3°). One-way ANOVA demonstrated a significant difference between the PI strata in total bony lordosis values with a mean difference of 14.0° between low and high PI cohorts (P < .001) and also mid- and high PI cohorts of 9.9° (P = .008). Overall, distal lordosis represented 80.8% of the total lordosis. In the proximal lumbar segments, the mean contribution from bone was −4.0° (SD 6.8°) and the mean contribution from disc was 13.6° (SD 6.0°). In the distal, the mean contribution from bone was 14.7° (SD 6.5°) and from disc, 22.7° (SD 6.2°). CONCLUSIONS: The contribution to lordosis from the vertebral bodies is greater in the proximal lumbar spine with increasing PI. With low PI, the proximal vertebral bodies demonstrate reduced contribution to lordosis and in some instances are kyphotic. Future research efforts should place greater emphasis on providing segmental rather than just global analysis of alignment. CLINICAL RELEVANCE: Restoration of lumbar spine lordosis should take into account the variation in segmental lordosis contributions as it relates to PI.

Background: Recent studies support the need for sagittal alignment restoration when performing lumbar degenerative spinal fusions. The development of patient-specific spine rods (PSSRs) may help maintain or improve sagittal alignment in these surgeries. Methods: A retrospective review was conducted for patients who underwent posterior spinal surgeries involving 4 or less levels. The preplanned PSSR radii of curvature (ROC) was compared with standard prebent rods with a ROC of 125 mm. All surgeries were performed at a single institution by 3 surgeons from September 2016 through October 2018. Data were then compared using a 2-tailed paired t test. PSSR had either 1 or 2 definitive ROCs. Results: For rods with 2 ROCs, the “cranial” curve was measured between the upper instrumented level and L4 or L5. The “caudal” curve was measured between L4 or L5 and the lower instrumented level. The PSSR with 1 ROC and the caudal portion of the rods with 2 ROCs were significantly smaller than the industry standard ROC. Conclusions: PSSR demonstrate more acute ROC than industry standard rods. In PSRs, the most lordosis occurs between L4-S1 and flattens out at the thoracolumbar junction, mimicking the normal distribution of lumbar lordosis. PSSRs could help achieve or maintain sagittal alignment and prevent the sequela of flat back syndrome.

Pelvic incidence (PI) is assumed to be fixed, yet studies have reported PI changes after long fusions to the pelvis. In a cohort of ASD patients undergoing surgery with S2-alar-iliac (S2AI) screws, we sought to: (1) report the magnitude of PI changes, and (2) evaluate subsequent pelvic parameter changes. A retrospective case series of ASD patients undergoing surgical correction with S2AI screw placement and sagittal cantilever correction maneuvers was conducted. Patients were categorized based on preoperative PI: High-PI (H-PI) (PI ≥ 60°); Normal-PI (N-PI) (60° > PI > 40°); Low-PI (L-PI) (PI ≤ 40°). PI was measured preoperatively and immediately postoperatively. A significant PI change was established a priori at ≥ 6.0. PI, pelvic tilt (PT), lumbar lordosis (LL), and PI-LL mismatch were analyzed. In 68 patients (82.3% female, ages 22–75 years), the average change in PI was 4.6° ± 3.1, and 25 (36.8%) had a PI change ≥ 6.0° with breakdown as follows: H-PI 12 (66.7%) patients, 9 (25.87%) patients, and 4 (33.3%) patients. Of 25 patients with PI changes, 10 (14.7%) had a PI increase and 15 (22.1%) had a PI decrease. Significant improvements were seen in PT, LL, PI-LL mismatch in all patients with a PI change ≥ 6.0°, in addition to both subgroups with an increase or decrease in PI. PI changes of ≥ 6.0° occurred in 36.8% of patients, and H-PI patients most commonly experienced PI changes. Despite PI alterations, pelvic parameters significantly improved postoperatively. These results may be explained by sacroiliac joint laxity, S2AI screw placement, or aggressive sagittal cantilever techniques.

STUDY DESIGN Within-subject design of an experimental study. OBJECTIVE The aim of this study was to determine the effects of smartphone use on the activity level of the lumbar erector spinae muscles and spine kinematics during walking. SUMMARY OF BACKGROUND DATA Using a smartphone while walking makes the user hold the phone steady and look downward to interact with the phone. Walking with this non-natural posture of the head and the arms may alter the spine kinematics and increase the muscular load on the low back extensor muscles. METHODS Twenty healthy young individuals participated in the laboratory experiment. Each participant walked on a treadmill in five different conditions: normal walking without using a phone, conducting one-handed browsing while walking, two-handed texting while walking, walking with one arm bound, and walking with both arms bound. Spine kinematics variables and the myoelectric activity levels of the lumbar erector spinae muscles were quantified and compared between the five walking conditions. RESULTS Participants walked with significantly (P

BACKGROUND: It is presently unknown if lumbar lordosis (LL) might be applied to monitor low back pain (LBP) in patients with lumbar disc herniation (LDH). There is presently only conflicting data that does not show a correlation of LL with LBP: Previous studies do either include chronic LBP or do not consider that each patient has an individual value of LL that cannot be compared to other patients. METHODS: Power analysis: At least 32 patients had to be enrolled in the study. Out of 84 consecutive patients with acute onset of pain (

We aim at analysing the impact of anterior lumbar interbody fusion (ALIF) in restoring the main spinopelvic parameters, along with its potentials and limitations in correcting sagittal imbalance. The 2009 PRISMA flow chart was used to systematically review the literature; 27 papers were eventually selected. The following spinopelvic parameters were observed: pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL), segmental lumbar lordosis (LLseg) and sagittal vertical axis (SVA). Papers reporting on hyperlordotic cages (HLC) were analysed separately. The indirect decompression potential of ALIF was also assessed. The clinical outcome was obtained by collecting visual analogue scale (VAS) for back and leg pain and Oswestry Disability Index (ODI) scores. Global fusion rate and main complications were collected. PT, SS, LL, LLseg and SVA spinopelvic parameters all improved postoperatively by − 4.3 ± 5.2°, 3.9 ± 4.5°, 10.6 ± 12.5°, 6.7 ± 3.5° and 51.1 ± 44.8 mm, respectively. HLC were statistically more effective in restoring LL and LLseg (p

Background: The prevalence of an abnormal spinopelvic relationship in patients presenting for primary total hip arthroplasty (THA) is not well known. The purpose of this study was to identify the prevalence of abnormal spinopelvic relationships in patients presenting for primary THA. Methods: A retrospective chart review of 338 consecutive, nonselected patients undergoing primary THA from the practice of 2 fellowship-trained adult reconstruction surgeons was performed (J.E.O. and T.S.B.). Sitting and standing radiographs were measured for lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SSstand), and pelvic tilt; the sacral slope was also measured on sitting radiographs (SSsit). Patients were assessed for the presence of spinopelvic imbalance, defined as PI–LL>10°, and decreased spinopelvic motion, defined as SSstand–SSsit< 10°. Descriptive statistics were reported. Results: A cohort of 338 patients was identified; 110 were excluded. In total, 228 unique patients underwent measurement. One hundred one of 228 patients (44.3%) in the cohort were female. The mean age of the cohort was 60.0 ± 13 years, with the mean body mass index of 31 ± 7 mg/kg2. Spinopelvic imbalance (PI–LL > 10°) was present in 142 of 228 patients (62.3%). Decreased motion at the spinopelvic junction (SSstand–SSsit < 10°) was present in 78 of 228 patients (34.2%). Fifty (21.9%) patients had both spinopelvic imbalance and decreased spinopelvic motion. Conclusions: In a cohort of 228 patients presenting for primary THA, the prevalence of spinopelvic imbalance was 62.3%, the prevalence of decreased spinopelvic motion was 34.2%, and the prevalence of both spinopelvic imbalance and decreased spinopelvic motion was 22%. Hip surgeons are likely to encounter patients with abnormal spinopelvic relationships.

The purpose of this study is to determine whether simulated radiographs in the "flexed-seated" or "step-up" positions better demonstrate a patient's range of spinopelvic motion between standing and sitting positions than relaxed sitting and standing radiographs.An institutional review board approved cohort of 43 patients with hip osteoarthritis whom underwent full body sitting-standing radiographs from August 2016 to December 2017 at a single institution was reviewed. Subjects underwent single-leg step-up standing and flexed-seated radiographs, and relaxed standing and sitting radiographs. Sacral slope, spinopelvic tilt (SPT), and lumbar lordosis were measured in all radiographs. Alignment parameters were compared between both sets of imaging, and the change in SPT between the imaging modalities was plotted and stratified by pre-existing lumbar pathology.There were significant differences between the relaxed standing and step-up radiographs and the relaxed and flexed-seated radiographs for sacral slope, SPT, and lumbar lordosis (P.002 for all), with the exception of SPT in the relaxed and step-up standing postures (P = .110). When transitioning from the standing to sitting position, the mean changes in SPT differed significantly between both sets of radiographs. Most importantly, when plotting changes in SPT between flexed and relaxed sitting postures, patients with fusions and flatback deformity trended toward greater anterior pelvic tilting, a position of greater risk of posterior dislocation.Flexed sitting and single-leg standing imaging may emphasize the compensatory mechanisms of patients with concomitant hip and spine pathology more than relaxed imaging using our measurements. Our method may provide insight into high dislocation risk patients compared to the previously published hip measurement method.III.

Purpose Aim of this study was to compare the reconstruction of radiological sagittal spinopelvic parameters between lordotic (10°) and normal cages (0°) after dorsal lumbar spondylodesis. Methods This retrospective monocentric study included patients who received dorsal lumbar spondylodesis between January 2014 and December 2018. Inclusion criteria were degenerative lumbar diseases and mono- or bi-segmental fusions in the middle and lower lumbar region. Exclusion criteria were long-distance fusions (3 segments and more) and infectious and tumour-related diseases. The sagittal spinopelvine parameters (lumbar lordosis, segmental lordosis, sacral slope, pelvic incidence, and pelvic tilt) were measured pre- and post-operatively by two examiners at two different times. The patients were divided into 2 groups (group 1: lordotic cage, group 2: normal cage). Results One hundred thirty-eight patients (77 female, 61 male) with an average age of 66.6 ± 11.2 years (min.: 26, max.: 90) were included in the study based on the inclusion criteria. Ninety-two patients (66.7%) received 0° cages and 46 (33.3%) lordotic cages (10°). Segmental lordosis was increased by 4.2° on average in group 1 and by 6.5° in group 2 (p = 0.074). Average lumbar lordosis was increased by 2.1° in group 1 and by 0.6° in group 2 (p = 0.378). There was no significant difference in the correction of sagittal spinopelvic parameters. Inter- and inter-class reliability was between 0.887 and 0.956. Conclusion According to the results of our study, no advantages regarding sagittal radiological parameters for the implantation of a lordotic cage could be demonstrated.

Background: Severe, rigid thoracolumbar scoliosis presents a surgical challenge to achieve 3-dimensional correction, maximize distal motion segments, and avoid operative morbidity conferred by combined anterior-posterior approaches or 3-column osteotomies. We present a new approach for releasing these curves, using multilevel posterolateral convex disc release (PCDR) and posterior instrumented fusion. Methods: There were 3 adults and 1 adolescent (mean age, 31.8 years; 2 females) with severe progressive thoracic and transforaminal lumbar (major) idiopathic scoliosis (IS) who were treated with 3-level PCDR, multiple posterior column osteotomies, and posterior instrumented thoracolumbar fusion with all–pedicle screw constructs. Results: Restoration of global coronal and sagittal alignment was achieved for all patients (minimum 2-year follow-up). Lowest instrumented vertebra (LIV) was L4 in 2 patients and L3 in the remaining 2. All except 1 were fused to the lower end vertebra. Postoperatively, mean thoracolumbar curve was reduced from 77.3° (range, 69°–91°) to 21.8° (72%Δ), LIV tilt decreased from 26.8° to 8.3°, and LIV translation improved (2.5–1.2 cm; 58%Δ), whereas lumbar lordosis remained unchanged. Average central sacral vertical line shift measured via C7 sagittal vertical axis changed from 1.4 to −0.7 cm. There were no complications except for dysesthesias in the lower extremity on the side of the PCDR in 1 patient, which resolved after 3 months. Conclusions: Severe thoracolumbar IS presents a surgical challenge to achieve 3-dimensional correction, minimize fusion levels, and avoid procedural morbidity. PCDR is a novel technique that may facilitate this correction with minimal procedure-related morbidity.

Relevance It is known that the state of sagittal balance is strictly correlated with the quality of life of the patient. At the same time, reference values for correction of sagittal parameters of the spine are derived only from vertical radiographs. Current evidence shows that the use of only standardized sagittal parameters in the standing position for planning the volume of surgical reconstruction is erroneous. However, rare publications show the difference between the sagittal profile of the spine in the sitting and standing position related to age. There is no information on the profile in extended degenerative pathology of the spine. Aim of the study Comparative assessment of the variability of the parameters of the sagittal profile of patients with Hip-Spine syndrome in the standing and sitting positions and comparison with healthy subjects from the average population. Design A prospective case-control monocenter observational study with historical control. The study included 74 patients with "Hip-spine" syndrome at the age of 63 ± 9.9 (43 to 83) years at the time of examination. The recruitment period was 23 months. The main group was formed by 74 patients with Hip-Spine syndrome. The control group (58 subjects) was represented by healthy individuals from open sources on the average population. The criteria of the analysis were sagittal vertebral-pelvic parameters of the trunk - CL, TK, TLK, LL, PI, PT, SS, SVA. The calculation of sagittal parameters was performed with Surgimap Spine software. Results In all patients during the transition from standing to sitting, there was kyphotization of the thoracolumbar transition (mean TLK angle was 10.3° – 145 %), a decrease in lumbar lordosis (mean LL angle – 23° – 44.4 %) with pelvic retroversion (PT: 18.6° – 126.5 %, SS: 18.3° – 51.6 %) and an increase in forward SVA deviation (10.5 mm – 25.5 %). No significant changes in cervical lordosis and thoracic kyphosis were revealed. When comparing the average values of sagittal parameters of patients of the main and control groups, there were no significant differences. However, among all patients of the main group, there were 6 patients (8.1 %) in whom the difference in the parameters LL, SS, PT in the standing and sitting positions was less than 10°, which indicates a pronounced rigidity of the lumbosacral spine. Conclusion Postural sagittal vertebral-pelvic parameters of the trunk in the standing and sitting positions in patients with Hip-Spine syndrome differ significantly from each other. A key role in the changes is played by the position of the pelvis, which retains mobility, despite different severity of degenerative changes in the complex "hip joints-lumbosacral spine".

BACKGROUND Systematic observations of fetal posture show that, although for most of the time the fetus does not have a preferred posture, it has a certain repertoire of repeated active postures. The observed postures cannot be considered random configurations of head and limb position: the fetus and the young infant have an active, but variable posture that is relatively unrelated to the orientation of the force of gravity. MATERIALS AND METHOD The study included 101 children, aged 6-7, including 50 preterm children, 48 boys and 53 girls (research group) and 51 full-term children; 22 boys and 53 girls (control group). The photogrammetric method with moire effect on Mora 4G CQ Elektronik was used to examine the body posture. RESULTS Significant statistical differences in GAMMA (p< 0.001) and KLL (p= 0.020) parameters in preterm children and in control group were noted. Both parameters presented higher value in the control group. CONCLUSIONS The posture of preterm children is characterized by a smaller angle of upper thoracic curvature and smaller angle of lumbar lordosis. The posture of preterm children in sitting position is characterized by a smaller angle of thoracic kyphosis. Preterm birth disturbs the development of proper antigravitational mechanism and causes possible posture dysfunctions at the age of 6.

To assess the effect of upright, seated, and supine postures on lumbar muscle morphometry at multiple spinal levels and for multiple muscles. Six asymptomatic volunteers were imaged (0.5 T upright open MRI) in 7 postures (standing, standing holding 8 kg, standing 45° flexion, seated 45° flexion, seated upright, seated 45° extension, and supine), with scans at L3/L4, L4/L5, and L5/S1. Muscle cross-sectional area (CSA) and muscle position with respect to the vertebral body centroid (radius and angle) were measured for the multifidus/erector spinae combined and psoas major muscles. Posture significantly affected the multifidus/erector spinae CSA with decreasing CSA from straight postures (standing and supine) to seated and flexed postures (up to 19%). Psoas major CSA significantly varied with vertebral level with opposite trends due to posture at L3/L4 (increasing CSA, up to 36%) and L5/S1 (decreasing CSA, up to 40%) with sitting/flexion. For both muscle groups, radius and angle followed similar trends with decreasing radius (up to 5%) and increasing angle (up to 12%) with seated/flexed postures. CSA and lumbar lordosis had some correlation (multifidus/erector spinae L4/L5 and L5/S1, r = 0.37–0.45; PS L3/L4 left, r = − 0.51). There was generally good repeatability (average ICC(3, 1): posture = 0.81, intra = 0.89, inter = 0.82). Changes in multifidus/erector spinae muscle CSA likely represent muscles stretching between upright and seated/flexed postures. For the psoas major, the differential level effect suggests that changing three-dimensional muscle morphometry with flexion is not uniform along the muscle length. The muscle and spinal level-dependent effects of posture and spinal curvature correlation, including muscle CSA and position, highlight considering measured muscle morphometry from different postures in spine models.

Study Design: Retrospective single-center study. Objective: Investigate the effect of posterior instrumentation on the relationship between lordosis and kyphosis. Methods: Surgically treated patients with a minimum of 6 months of follow-up were analyzed. Asymptomatic volunteers served to show the normal anatomical relationship between thoracic and lumbar curves. Patients were stratified based on postoperative instrumentation: “Thoracic Fusion” = complete fusion of thoracic spine; “Lumbar Fusion” = complete fusion of lumbar spine; and “Complete Fusion” = fusion from sacrum to at least T5. Bivariate correlations and regression analysis were used to evaluate the relationship between change in thoracic kyphosis (ΔTK) and change in spinopelvic mismatch (ΔPI-LL; pelvic incidence-lumbar lordosis) before and after fusion. Analyses were repeated in “Lumbar Fusion” patients with flexible preoperative thoracic spines. Results: For asymptomatic volunteers, the natural anatomical relationship between TK and LL was found to be TK = 41% of LL ( r = 0.425, P < .001). A total of 153 of 167 adult spinal deformity patients were included (62 years old, 26.7 kg/m2, 78% female). Mean follow-up was 11.5 ± 6.8 months. “Thoracic Fusion” group showed no alteration in the natural relationship between TK and LL (ΔTK = 39% ΔPI-LL), whereas “Lumbar Fusion” group had a reduction in reciprocal change (ΔTK = 34% ΔPI-LL) although a subanalysis of patients in the “Lumbar Fusion” group with flexible thoracic spines showed a marked compensation in reciprocal change with (ΔTK = 58% ΔPI-LL). Conclusion: The relationship between ΔTK and ΔPI-LL is dependent on level instrumented. “Thoracic Fusion” drives change in LL while this relationship is affected by TK’s natural stiffness in “Lumbar Fusion” patients.

Distal thoracic kyphosis (DTK) equivalent to proximal lumbar lordosis (PLL) is the sum of pelvic tilt (PT) and the difference (Δ) between lumbar lordosis (LL) and pelvic incidence (PI): PLL = DTK = PT + Δ. With the assumption that proximal thoracic kyphosis (PTK) is similar to DTK, we propose the equation TK = 2(PT + LL − PI) to express the relationship between thoracic kyphosis (TK) and pelvic parameters. The objective of this work is to verify this relationship in a normal population. Full spine radiographs of 100 adolescents and young adults (13 to 20 years old), free from vertebral pathology, were analyzed. Measurements included pelvic parameters, LL, PLL, DLL, TK, PTK, DTK and C7 global tilt. The measured global TK was compared with the theoretical TK calculated according to the formula TK = 2(PT + LL − PI). The difference between measured TK and calculated TK was + 2.3° and correlated with the C7 global tilt (r = 0.86). There was a significant linear regression between TK and PT + ∆ (p

The global alignment and proportion (GAP) score was recently developed to consider proportional analysis of spinopelvic alignment and has been indicated for setting surgical goals to decrease the prevalence of mechanical complications. The goal of this study was to clarify the limitations and problems with spinal corrective surgery with minimally invasive lateral lumbar interbody fusion (LLIF) without osteotomy using GAP score, and to establish a preoperative radiographical evaluation to understand the necessity for three-column osteotomy. We included data from 57 consecutive patients treated with spinal corrective surgery with LLIF and without Schwab grade 3–6 osteotomy for ASD. To evaluate flexibility of the pelvis and lumbar spine, we examined full-length lateral radiographs with patients standing and prone. Correlations between pre- and postoperative radiographic parameters and GAP score were determined. Most patients achieved a sufficiently ideal lumbar lordosis (87.7%), but ideal sacral slope (SS) was achieved in only 50.8% of patients. Preoperative prone SS showed a significant positive correlation with postoperative SS and a significant negative correlation with GAP score. Patients whose preoperative prone SS was larger than pelvic incidence × 0.59–7.5 tended to achieve proportioned spinopelvic alignment by using LLIF. The cause of poor outcome of GAP score for ASD corrective surgery with LLIF without osteotomy is a postoperative small SS. Preoperative prone SS is useful for predicting postoperative SS. When preoperative SS in prone patients is relatively small to ideal as calculated using PI, osteotomy or other correctors should be considered to achieve satisfactory spinopelvic parameters. III. These slides can be retrieved under Electronic Supplementary Material.

STUDY DESIGN This was a systematic review. OBJECTIVE The objective of this study was to review radiographic, clinical, and surgical outcomes of expandable interbody device implantation following lumbar fusion. SUMMARY OF BACKGROUND DATA Few studies have evaluated postsurgical outcomes of expandable implants following lumbar interbody fusion. METHODS A systematic review was performed to identify studies investigating expandable intervertebral body devices in lumbar fusion. Radiographic parameters, fusion assessments, patient-reported outcomes (PROs), complications, and revision data were recorded. A comparison of expandable and static devices was performed using a meta-analysis. RESULTS Eleven articles were included. Postoperative improvements for each radiographic parameters for expandable versus static device implantation ranged from: lumbar lordosis, +2.0 to +5.0 degrees (expandable) versus +1.0 to +4.4 degrees (static); segmental lordosis, +1.0 to +5.2 degrees (expandable) versus+1.1 to +2.3 degrees (static); disk height, +0.82 to +4.8 mm (expandable) versus +0.26 to +6.9 mm (static); foraminal height, +0.13 to +2.8 mm (expandable) versus and +0.05 to +3.0 mm (static). Fusion rates ranged from 72.1% at 6 months to 100% at terminal follow-up. Preoperative to final follow-up improvement for the various PROs assessed were: Oswestry Disability Index, -15.4 to -56.3 (expandable) versus -13.6 to -26.3 (static); Visual Analog Scale (VAS) Back, -3.2 to -6.0 (expandable) versus -3.1 to -4.1 (static); and VAS Leg, -2.9 to -7.1 (expandable) -3.0 versus -4.8 (static). Static cages had a reported complication rate ranging from 6.0% to 16.1% and a subsidence rate of 6.0%. Expandable cages had a reported complication rate that ranged from 0.0.% to 10.0% and a subsidence rate of 5.5%-10.0%. A meta-analysis demonstrated a statistically significant difference in the PRO Oswestry Disability Index, but not VAS Back, VAS Leg, or radiographic outcomes (disk height or foraminal height). CONCLUSION There is no clear evidence for the use of expandable interbody devices over static devices.

STUDY DESIGN: Prospective cross-sectional case-control study design. OBJECTIVE: This study aims to analyze the relation between balance control as well as health-related quality of life (HRQOL) in patients with adult spinal deformity (ASD), with a novel gravity line (GL)-related 3D spinal alignment parameter, the transverse gravitational deviation index (TGDI), defined to quantify the transverse plane position of any vertebra with respect to the GL. SUMMARY OF BACKGROUND DATA: Demographic data and balance control have both been identified as important determinants of HRQOL in ASD patients during a preoperative setting. Therefore, a better understanding of the relation between spinal alignment and balance is required. METHODS: After informed consent, 15 asymptomatic healthy volunteers (mean age 60.1 ± 11.6 years old) and 55 ASD patients (mean age 63.5 ± 10.1 years old) were included. Relation between performance on BESTest as well as core outcome measures index (COMI) with spinopelvic alignment was explored using General Linear Modeling (GLM). A P-value ≤0.05 was considered statistically significant. RESULTS: The L3 TGDI was identified to relate to balance control in the total ASD population after correction for confounding demographic factors (P = 0.001; adjusted R = 0.500) and explained 19% of the observed variance in balance performance. In addition, COMI is related to L3 TGDI in a subgroup of ASD patients with combined coronal and sagittal malalignment of L3 (P = 0.027; slope B = 0.047), despite significant influence of age (P = 0.020). CONCLUSION: In ASD patients with a combined coronal and sagittal malalignment of the L3 vertebra, both the level of balance impairment as well as HRQOL are related to the distance component of the L3 TGDI, that is, the offset between the center of the L3 vertebral body and the GL in the transverse plane. LEVEL OF EVIDENCE: 2. ispartof: SPINE vol:45 issue:1 pages:E25-E36 ispartof: location:United States status: published

Aims Spinopelvic mobility plays an important role in functional acetabular component position following total hip arthroplasty (THA). The primary aim of this study was to determine if spinopelvic hypermobility persists or resolves following THA. Our second aim was to identify patient demographic or radiological factors associated with hypermobility and resolution of hypermobility after THA. Methods This study investigated patients with preoperative posterior hypermobility, defined as a change in sacral slope (SS) from standing to sitting (ΔSSstand-sit) ≥ 30°. Radiological spinopelvic parameters, including SS, pelvic incidence (PI), lumbar lordosis (LL), PI-LL mismatch, anterior pelvic plane tilt (APPt), and spinopelvic tilt (SPT), were measured on preoperative imaging, and at six weeks and a minimum of one year postoperatively. The severity of bilateral hip osteoarthritis (OA) was graded using Kellgren-Lawrence criteria. Results A total of 136 patients were identified as having preoperative spinopelvic hypermobility. At one year after THA, 95% (129/136) of patients were no longer categorized as hypermobile on standing and sitting radiographs (ΔSSstand-sit < 30°). Mean ΔSSstand-sit decreased from 36.4° (SD 5.1°) at baseline to 21.4° (SD 6.6°) at one year (p < 0.001). Mean SSseated increased from baseline (11.4° (SD 8.8°)) to one year after THA by 11.5° (SD 7.4°) (p < 0.001), which correlates to an 8.5° (SD 5.5°) mean decrease in seated functional cup anteversion. Contralateral hip OA was the only radiological predictor of hypermobility persisting at one year after surgery. The overall reoperation rate was 1.5%. Conclusion Spinopelvic hypermobility was found to resolve in the majority (95%) of patients one year after THA. The increase in SSseated was clinically significant, suggesting that current target recommendations for the hypermobile patient (decreased anteversion and inclination) should be revisited. Cite this article: Bone Joint J 2021;103-B(12):1766–1773.

STUDY DESIGN Single-center retrospective review of outcomes among three surgical techniques in the treatment of thoracic idiopathic scoliosis (T-AIS) with a follow-up of at least 5 years. OBJECTIVE To investigate how outcomes compare in video-assisted anterior thoracic instrumentation (VATS), all hooks/hook-pedicle screw hybrid instrumentation (HHF), and all pedicle screw instrumentation (PSF) techniques for T-AIS. SUMMARY OF BACKGROUND DATA Studies comparing outcomes for anterior vs posterior fusion for T-AIS are few and with short follow-up. METHODS Three groups of patients with T-AIS who underwent thoracic fusion were included in this study: 98 patients with mean curve of 49.0° ± 9.5° underwent VATS (Group 1); 44 patients with mean curve of 51.1° ± 7.4° underwent HHF (Group 2); and 47 patients with mean curve of 47.6° ± 9.9° underwent PSF (Group 3). Radiological outcomes were compared at pre-operative, and up to 5 years. Surgical outcomes were noted until latest follow-up. RESULTS Group 1 had less blood loss, less fusion levels, longer surgical time, and longer hospital stay compared to the other groups (p

PURPOSE: The objective of this study was to compare clinical and radiologic parameters between minimally invasive surgery–transforaminal lumbar interbody fusion (MIS-TLIF) and open TLIF. METHODS: Data of 145 patients who underwent single- or double-level TLIF procedures with an open (n = 76) or a MIS (n = 69) technique were analyzed. Average operation time, estimated blood loss, and hospital stay were compared between open TLIF and MIS-TLIF. Improvement in clinical scores was analyzed using visual analog scale (VAS) and Oswestry Disability Index (ODI) scores in both groups and statistically compared using t tests. Radiologic parameters, such as lumbar lordosis, focal lordosis at the index level, and pelvic incidence (PI), were calculated at preoperative, postoperative, and final follow-up for comparison. The differences in improvement between open and MIS groups were analyzed using unpaired t tests. RESULTS: Average follow-up was 35.8 ± 15.4 months in open TLIF and 37.9 ± 14.4 months in MIS-TLIF. The average blood loss and operation times were higher and hospital stay was less in MIS-TLIF compared to open TLIF. VAS scores were improved from preoperative (8.5 ± 0.6) to postoperative (2.1 ± 0.8) and preoperative (8.4 ± 0.8) to postoperative (2.0 ± 0.7) in open TLIF and MIS-TLIF, respectively (P < .0001), and ODI scores were improved from preoperative (55.2 ± 5.2) to postoperative (22.5 ± 4.3) and preoperative (56.7 ± 4.9) to postoperative (22.0 ± 5.0) in open TLIF and MIS-TLIF, respectively (P < .0001). Similarly, there were significant improvements in lumbar lordosis and focal lordosis at the index level with a difference of 3.9° and 2.5°, respectively, in open TLIF and 4.0° and 2.9°, respectively, in MIS-TLIF. However, there were no differences in PI in both groups. There were 9 (11.8%) and 9 (13%) complications encountered in open TLIF and MIS-TLIF, respectively. Two patients from open TLIF and 5 from MIS-TLIF had to undergo revision surgeries without any statistical difference. CONCLUSIONS: Open TLIF and MIS-TLIF are equally efficient surgical techniques with similar clinical and radiologic outcomes. MIS-TLIF is associated with less intraoperative blood loss and hospital stay; however, it increases operation time significantly.

Study Design: Retrospective study. Objectives: To investigate the effect of paraspinal muscle degeneration on the maintenance of local and global alignment among degenerative lumbar scoliosis (DLS) patients after corrective surgery. Methods: 98 DLS patients with a mean follow-up period of 38.3 months after corrective surgery were included. The T1 pelvic angle (TPA), lumbar lordosis (LL), pelvic incidence were measured preoperatively, immediate postoperatively and at last follow-up. All patients were divided into LL maintenance group (n = 21) and LL loss group (n = 77). For patients with well-aligned correction (immediate postoperative TPA ≤ 20°, n = 73), they were divided into TPA maintenance group (last follow-up TPA ≤ 20°) and TPA loss group (last follow-up TPA > 20°). The relative gross cross-sectional area (rGCSA) and fat infiltration (FI) of multifidus (MF) and erector spinae (ES), and the relative functional CSA (rFCSA) of psoas major (PS) were measured at L3, L4 and L5 on preoperative magnetic resonance imaging. Results: MF rGCSA were significantly smaller in LL loss group than in LL maintenance group. Both MF rGCSA and PS rFCSA were significantly smaller and MF FI was significantly higher in TPA loss group than in TPA maintenance group. Binary logistic regression revealed that the MF rGCSA was an independent factor of LL loss; Large immediate postoperative TPA was an independent risk factor of TPA loss, but not the parameters of paraspinal muscles. Conclusion: The effect of paraspinal muscles in lower lumbar segments might be mainly focused on the maintenance of local alignment rather than the global alignment.

Background This study aims to analyze postoperative changes of cervical sagittal curvature and to identify independent risk factors for cervical kyphosis in Lenke type 1 adolescent idiopathic scoliosis (AIS) patients. Methods A total of 124 AIS patients who received all-pedicle-screw instrumentation were enrolled. All patients were followed up for at least 2 years. The following parameters were measured preoperatively, immediately after the operation, and at the last follow-up: pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL), thoracic kyphosis (TK), global thoracic kyphosis (GTK), proximal thoracic kyphosis (PrTK), T1-slope, cervical lordosis (CL), McGregor slope (McGS), sagittal vertical axis (SVA), C2–7 SVA (cSVA), and main thoracic angle (MTA). Statistical analysis was performed to evaluate postoperative alterations of and correlations between the parameters and to identify risk factors for cervical kyphosis. Statistical significance was set at P Results After the operation, PrTK and T1-slope significantly increased (3.01 ± 11.46, 3.8 ± 10.76, respectively), cervical lordosis improved with an insignificant increase (− 2.11 ± 13.47, P = 0.154), and MTA, SS, and LL decreased significantly (− 33.68 ± 15.35, − 2.98 ± 8.41, 2.82 ± 9.92, respectively). Intergroup comparison and logistic regression revealed that preoperative CK > 2.35° and immediate postoperative GTK Conclusions Postoperative restoration of thoracic kyphosis, especially proximal thoracic kyphosis, and T1-slope play a central role in cervical sagittal compensation. Preoperative CK, postoperative small GTK, and insufficient △T1-slope are all independent risk factors for cervical decompensation.

Objective. To assess the effect of endocorrector rod fractures on the final result of treatment and the quality of life of patients operated on for spinal deformities of different etiology. Material and Methods . The study included 3833 patients older than 10 years who were operated on for spinal deformities of various etiologies and had not been subjected to spinal surgery before admission to the clinic. In the pre- and postoperative periods, spondylograms in frontal and lateral projections in the standing position were studied using the Cobb method, the apical vertebra rotation was determined in accordance with the method of Sullivan et al. Patients answered questions of the SRS-24 questionnaire in the immediate and long-term follow-up periods. Results . In total, fractures of metal implant rods were detected in 85 (2.2 %) patients. The average scoliotic deformity in these patients was 84.5° before surgery, 49.9° after surgery, and 53.7° at the end of the follow-up period (postoperative progression was 3.8°). Thoracic kyphosis was 61.5° before surgery, 44.3° after surgery, and 48.7° at the end of the follow-up period; lumbar lordosis – 68.4°, 54.8°, and 56.5°; and apical vertebra rotation – 55.8°, 33.2° and 35.8°, respectively. According to the questionnaire data, patients estimated their appearance after surgery and general appearance somewhat lower and pain as less intense. Indicators of activity and function of the spine after the rod remounting were slightly lower than after the primary surgery. Remounting did not significantly affect the indicator of “consent to surgical treatment under the same conditions” – 80.6 and 80.0 %. Conclusion. Complications in the form of rod fracture do not have a significant negative effect on the treatment result from the standpoint of assessing the quality of life, provided that the corrective effect of the surgical intervention is maintained in the horizontal, frontal and sagittal planes.

The purpose of the present study was to validate a new spinal sagittal classification. We retrospectively included 105 consecutive AIS patients who underwent posterior spinal fusion. Preoperative long-standing EOS radiographs were available on all patients. Patients were classified according to the four suggested sagittal patterns: type 1, 2a, 2b or 3. Several predetermined sagittal parameters were compared between the groups. The mean preoperative Cobb angle was 64° ± 12°, and 73% of the patients were female. Of 105 patients, 51 were type 1, 14 were type 2a, one was type 2b and 39 were type 3. The distribution of the four sagittal patterns was significantly different compared with the original publication (p

Currently, an upright standing posture is normally adopted for evaluations of spinal alignment, which is however sensitive to posture variations. Thus, finding a reproducible reference is essential. This study aimed to evaluate the reproducibility of standing and sitting postures at different arm positions in five consecutive repetitions.22 asymptomatic subjects (11 males; 11 females) aged 20-35 years were included. Subjects were repeatedly asked to adopt different arm positions in standing and sitting. The absolute reposition errors of lumbar lordosis and sacral orientation between two consecutive repetitions were assessed with a non-radiological back measurement system.During standing at the relaxed arm position, the median absolute reposition errors of lumbar lordosis and sacral orientation were 1.14° (range 0.23°-3.80°) and 0.92° (range 0.17°-3.27°), respectively, which increased to 1.75° (range 0.21-4.97°) and 1.36° (range 0.35°-4.08°) during sitting (P 0.01). The absolute reposition error of lumbar lordosis was non-significantly lower at the relaxed and clasped arm positions than at other arm positions. Between the first two repetitions, the absolute reposition errors of both, lumbar lordosis and sacral orientation, were greater than between the remaining two consecutive repetitions (P 0.01). Both during standing and sitting, lumbar lordosis was smallest when hands holding two bars (P 0.05).Sitting showed a worse reproducibility than standing. When assessing sagittal spinal balance, the clasped arm position during standing is recommended and an initial trial can help to reduce inception irreproducibility.

BackgroundLBP is a common and serious problem affecting vast populations of the world. However, only few studies on LBP in sub-Saharan Africa have been conducted. Studies report that LBP and pelvic angle are interrelated, and African residents have a high pelvic tilt. The strategy to prevent LBP should focus on activities that promote holistic health. For that purpose, it is important to grasp the state of LBP and how it affects people’s lifestyle in Tanzania to clarify the direction of implementation of physiotherapy treatment and reduce the incidences of LBP among adults. This study aimed to investigate the prevalence and presentation of low back pain (LBP) and the relationship between anthropometric measurements and LBP among people in Moshi city, Kilimanjaro region Tanzania.MethodsFollowing signing consent forms, participants were given questionnaires regarding LBP and then grouped accordingly into either asymptomatic or symptomatic cohorts. Anthropometric measurements of participants’ height, weight, curvature of the spine, and pelvic angle were obtained.ResultsA Mann-Whitney U test analysis showed a significant difference in pelvic angle, body mass index (BMI), and thoracic kyphosis angle between the asymptomatic group and the symptomatic group. No significant differences in lumbar lordosis angle or abdominal muscle strength were found between the two groups.ConclusionsA person with symptomatic LBP in Tanzania has a large anteversion of the pelvic tilt and a thoracic kyphotic posture. This study shows a relationship between sagittal spinal alignment and LBP in Tanzania, which could allow for prospective identification of subjects prone to developing LBP in the future.

Introduction. The aim of this study was to examine women participating in fitness activities regarding their level of disability in daily activities and lumbar lordosis. Material and methods. Data were collected from 68 females between the ages of 25-70 participating in fitness exercises. The Oswestry Disability Index was applied to measure the level of disability due to the low back pain in everyday life. The angle of lumbar lordosis was measured using a Saunders’ digital inclinometer. Results. The results of the study confirmed the existence of problems related to low back pain in people performing sedentary work. There were no correlations between lumbar lordosis angle and the level of disability in daily activities of the groups. The low back pain increases especially among people performing sedentary work. Conclusions. The results of this study suggest that work in a sitting position is not associated with a decrease in the angle of lordosis in relation to another work than in a sitting position. Sitting work can be an indirect cause of back pain and slight disability in everyday life by weakening postural muscles.

Study Design Retrospective case-control study. Purpose We aimed to compare radiologic outcomes between posterior (PLIF) and lateral lumbar interbody fusion (LLIF) in short-level spinal fusion surgeries. Overview of Literature Although LLIF enables surgeons to insert large lordotic cages, it is unknown whether LLIF more effectively corrects local and global sagittal alignments compared with PLIF in short-level spinal fusion surgeries. Methods Radiographic data acquired from patients with lumbar interbody fusion (≤3 levels) using PLIF or LLIF for degenerative lumbar diseases were analyzed. The following radiographic parameters were evaluated preoperatively and at 2 years postoperatively: segmental lordotic angle, disk height, lumbar lordosis (LL), pelvic tilt (PT), C7 sagittal vertical axis, and thoracic kyphosis (TK). Results In total, 144 patients with PLIF (193 fused levels) and 101 with LLIF (159 fused levels) were included. Patients’ backgrounds and preoperative radiographic parameters for any level of fusion did not differ significantly between PLIF and LLIF procedures. The LLIF group exhibited significantly greater changes at 1-level fusion compared to the PLIF group in the parameters of segmental lordotic angle (5.1°±5.8° vs. 2.1°±5.0°, p

Sagittal spinal alignment has mainly analyzed in the standing position. According to previous studies, there are significant differences in lumbopelvic alignment between the standing and sitting positions and cervical alignment is affected by lumbopelvic alignment. In this study, therefore, we hypothesized that cervical sagittal alignments are different between the standing and sitting positions.A total of 108 patients with spinal degenerative diseases underwent whole spine radiography. Cervical lordosis (CL), C2-7 SVA, T1S, C7-S1 SVA, TK, LL, SS, PT, and PI were measured in the standing and sitting positions. Patients were classified into 3 groups according to the changes in CL (ΔCL, CL in the sitting position - CL in the standing position); ΔCL -3° (Decreased group: DG; 28.7%), -3° ≤ ΔCL ≤ 3° (Unchanged group: UG; 41.7%), and ΔCL 3° (Increased group: IG; 29.6%).The parameters of the UG in the standing position were closer to the ideal alignment (SRS-Schwab classification). In the DG, CL, T1S, and C7-S1 SVA in the standing position were significantly higher than in the UG. In the IG, PI-LL in the standing position was significantly higher than in the UG. In the sitting position, pelvis was rotated posteriorly (decrease in SS and increase in PT) and lumbar lordosis was flattened (decrease in LL) in all groups, and C2-7 SVA was significantly higher in the DG than in the UG.CL was different between the standing and sitting positions in 58.3% of individuals. However, patients with good spinal sagittal alignment appeared to not undergo any changes in cervical alignment. Our results suggest the possibility that patients who had a positive imbalance and large PI-LL mismatch in the standing position had decreased CL and increased CL, respectively, when in the sitting position.

© 2019, Springer-Verlag GmbH Germany, part of Springer Nature. Purpose: This study was aimed to identify correlation between maximum isometric strength in five muscle groups determined by dynamometry results of muscle tests and the inclination angles of the spine. Methods: This predictive correlational study included 63 young healthy athletes aged 10–15. (m/f 31/32; 12.73 ± 1.58 years; 162.57 ± 12.94 cm; 52.86 ± 12.17 kg; 3.95 ± 1.70 training years; 4.05 ± 1.31 training h/week).The maximum isometric strength in five muscle groups was measured by a handheld dynamometer with external belt fixation using a portable stabilization device. The inclination angles were measured with a digital inclinometer. The data were analyzed using descriptive statistics, and correlations were estimated by Pearson’s correlation coefficient (r). Results: The isometric muscular strength of the muscle group of the hip extensors was in a significant correlation with the lumbar lordosis angle (LLA), r = 0.714 (p < 0.0001). The isometric muscular strength of the muscle group of the erector spinae was in a significant correlation with the LLA, r = 0.578 (p < 0.0001) and with thoracic kyphosis angle (TKA), r = 0.522 (p < 0.0001). Conclusion: There is a strong association between isometric strength of the muscle groups of the hip extensors and erector spinae and the inclination angles of the spine. Based on the isometric results, physical therapy can be proposed for increasing the muscular strength of those muscle groups, which can help in the prevention of more severe forms of postural deformities. Graphic abstract: These slides can be retrieved under Electronic Supplementary Material.[Figure not available: see fulltext.]

Study Design Retrospective clinical study on the indirect decompressive effect of oblique lateral interbody fusion (OLIF) for adult spinal deformity. Purpose To evaluate the effect of interbody distraction by OLIF for the treatment of adult spinal deformity. Overview of Literature Adult spinal deformity with symptomatic stenosis has been addressed conventionally using a direct posterior decompression approach with fusion. However, stenotic symptoms can also be alleviated indirectly through restoration of intervertebral and foraminal heights and correction of spinal alignment. Methods Twenty-eight patients with adult spinal deformity underwent OLIF combined with modified cortical bone trajectory screws at 94 lumbar levels with neuromonitoring. The patients were divided into three groups based on their preoperative lumbar lordosis: group A, 20°. The cross-sectional area (CSA) of the thecal sac was measured preoperatively and postoperatively on axial magnetic resonance images. Differences in CSA were evaluated, and the relationship between the CSA extension ratio and preoperative CSA was assessed. Changes in disc height and segmental disc angle were measured from plain radiographs. Results OLIFs were performed successfully without neural complications. In group A, the mean CSA increased from 120.6 mm2 preoperatively to 148.5 mm2 postoperatively (p