Pelvic Incidence Research Articles

Distance between the C2 vertical line and the femoral heads: a quasi-invariant global sagittal alignment parameter in both standing and sitting positions for asymptomatic adults.

This study aimed to investigate whether the distance between the C2 vertical line and the femoral heads (C2-FH) is quasi-invariant for the sitting position. A cross-sectional, prospective study was conducted. A cohort of 59 asymptomatic volunteers was prospectively recruited between February 1, 2020, and February 31, 2020, at Nanjing Drum Tower Hospital of Nanjing University Medical School. The following radiographical parameters were evaluated: T4-T12 thoracic kyphosis (TK), cervical lordosis (CL), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), sagittal vertical axis (SVA), T1-pelvic angle (TPA), and the C2-FH. The inclusion criteria were as follows: age between 18 and 35 years and no symptoms related to neck or back pain. The exclusion criteria were as follows: a history of any prior lower extremity or spine surgery; and a history of inflammatory arthritis, neuromuscular disorders, or congenital anomalies. Individuals were divided into the following 3 groups according to the percentile of ΔPT (PT difference between standing position and sitting position): group A (1-25% ΔPT, n=14), group B (25-75% ΔPT, n=30), and group C (75-100% ΔPT, n=15). Summary statistics calculated using analysis of variance (ANOVA) were used to provide 95% confidence intervals for measurement errors. The significance level of all statistical analyses was set as P < 0.05. There was no significant difference in any of the parameters among the 3 groups in the standing position. In the sitting position, for different degrees of pelvic retroversion, there were significant differences between the 3 groups in the other parameters except for C2-FH (P=0.80; 95% CI: -20.486 to -3.893), CL (P=0.47; 95% CI: -5.645 to 4.964), TK (P=0.54; 95% CI: 17.058-25.1), and PI (P=0.44; 95% CI: 40.747-49.087). Surprisingly, C2-FH changed slightly among the 3 groups in both the standing (P=0.87) and sitting (P=0.80) positions. As ΔPT gradually increased, ΔSS, ΔLL, ΔSVA, ΔL1-L4, ΔL4-S1, ΔTPA, ΔPT/PI, and ΔPI-LL showed corresponding gradual changes (all P values <0.05). However, there was no significant difference in PI (P=0.39), CL (P=0.46), C2-FH (P=0.51), or TK (P=0.51). C2-FH is a quasi-invariant parameter in both the standing and sitting positions for asymptomatic adults. The mean value of C2-FH was -11.95 mm in the standing position and -1.01 mm in the sitting position. Stable C2-FH could serve as a reference during the surgical decision-making process in adult patients with spinal deformity and sagittal malalignment.

Clinical outcomes and proximal junctional failure in adult spinal deformity patients corrected to normative alignment versus functional alignment.

The objective of this study was to explore the rate of proximal junctional failure (PJF) and functional outcomes of normative alignment goals compared with alignment targets based on age-appropriate physical function. Baseline relationships between age, pelvic incidence (PI), and a component of the T1 pelvic angle (TPA) within the fusion were analyzed in adult spinal deformity (ASD) patients and compared with those of asymptomatic patients. Linear regression modeling was used to determine alignment based on PI and age in asymptomatic patients (normative alignment), and in ASD patients, alignment corresponding to age-appropriate functional status (functional alignment). A cohort of 288 ASD patients was split into two groups based on whether the patient was closer to their normative or functional alignment goal at their 6-week postoperative radiographic follow-up. The rates of proximal junctional kyphosis (PJK) and PJF were determined for each cohort. In the 288 ASD patients included in this pre- to postoperative analysis, there was no difference in baseline alignment or health-related quality of life (HRQOL) between the normative alignment and functional alignment groups. At 6 weeks, patients with normative alignment had a smaller TPA (4.45° vs 14.1°) and PI minus lumbar lordosis (-7.24° vs 7.4°) (both p < 0.0001) and higher PJK (40% vs 27.2%, p = 0.03) and PJF (17% vs 6.8%, p = 0.008) rates than patients with functional alignment. Correction in ASD patients to normative alignment resulted in higher rates of PJK and PJF without improvements in HRQOL. Correction in ASD patients to functional alignment that mirrors the physical function of their age-matched asymptomatic peers is recommended.

Efficacy of polyetheretherketone rod hybrid surgery in preventing proximal junctional failure after adult spinal deformity surgery

Objective: To investigate the clinical outcome and preventive effect of polyetheretherketone(PEEK) rod hybrid surgery on proximal junction failure(PJF) after long-segment fusion of adult spinal deformity. Methods: A retrospective study was conducted to analyze patients with degenerative scoliosis/kyphosis who underwent long-segment decompression and fusion surgery at Department of Orthopedics, Peking University First Hospital from January 2017 to December 2021. A total of 75 patients were included in the study, including 14 males and 61 females, aged (67.2±6.8)years (range:55 to 84 years). According to the operation method chosen by the patients, the patients were divided into PEEK rod hybrid group (20 cases) and traditional titanium rod group (55 cases). The general information of the patients was collected, and the coronal and sagittal parameters of the spine were measured before operation, at 1 month after operation, and at the last follow-up. The clinical effect of surgery was judged by the visual analogue scale (VAS) and Oswestry disability index (ODI). Whether proximal junctional kyphosis (PJK) and PJF occurred during the follow-up and the time of occurrence were recorded. Comparisons between groups were performed using independent sample t test, Mann-Whitney U test, χ2 test and Fisher's exact probability method. The data before and after surgery in the same group were compared using the paired sample t test and the Wilcoxon test. Results: There were no significant differences in age, gender, body mass index, bone mineral density, distal instrumented vertebrae, surgical segments, osteotomy method, operation time, and intraoperative bleeding between the two groups (all P>0.05). The follow-up time of the PEEK rod group was shorter(M(IQR)16.5(4.8) vs. 25.0(12.0),Z=-4.230,t<0.01). There were no significant differences in coronal, sagittal parameters, VAS, and ODI between the two groups before operation (all P>0.05). Postoperative coronal Cobb angle, pelvic incidence, pelvic tilt, sacral slope, lumbar lordosis, thoracic kyphosis, sagittal vertical axis (SVA), VAS, and ODI were significantly improved in both groups(all P<0.05). At the last follow-up, the SVA of the PEEK rod hybrid group was(3.74±2.40)cm, which was significantly lower than that of the titanium rod group (6.28±4.06)cm (t'=-3.318, P=0.002). At the last follow-up, the ODI of the PEEK rod hybrid group was 30.7±6.1, significantly better than the titanium rod group 39.3±17.2. PJK occurred in 2 patients (10.0%) in the PEEK rod hybrid group, and no PJF phenomenon was observed. In the titanium rod group, 18 patients (32.7%) developed PJK, and 11 patients (20.0%) developed PJF. There was a statistically significant difference in the incidence of PJF between the PEEK rod hybrid group and the titanium rod group (P=0.031). Conclusions: PEEK rod hybrid surgery can achieve good clinical results in the treatment of adult spinal deformities. Compared with traditional titanium rod surgery, it can significantly reduce the incidence of postoperative PJF and improve the clinical function of patients.

Isokinetic strength assessment of trunk muscle and its relationship with spinal-pelvic parameters in patients with degenerative spinal deformity.

The incidence rate of degenerative spinal deformity (DSD) has gradually increased in the elderly. Currently, the relationship between the functional status of trunk muscle and the spinal-pelvic parameters of DSD patients remains unclear. This paper aims to explore the relationship between the two factors and provide new clues for exploring the mechanism of the occurrence and development of DSD. A total of 41 DSD patients treated in our hospital (DSD group) and 35 healthy volunteers (control group) were selected. Muscle strength was evaluated using an IsoMed-2000 isokinetic dynamometer, and the trunk flexor and extensor peak torque (PT) of subjects was measured at a low, medium, and high angular velocity of 30∘/s, 60∘/s, and 120∘/s, respectively. Hand grip strength (HGS) was assessed using an electronic grip dynamometer and Surgimap software was used to measure the spinal-pelvic parameters, including the sagittal vertical axis (SVA), thoracic kyphosis (TK), lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT), pelvic incidence rate (PI), and PI-LL, and the relationship between trunk muscle function and various parameters was analyzed. Under the three angular velocities, the flexor and extensor PT values in the DSD group were lower than those in the control group, and only the extensor PT showed a statistically significant difference (P< 0.05). There was no significant difference in HGS between the two groups (P> 0.05). In the DSD group, the extensor PT at 30∘/s was significantly negatively correlated with SVA (P< 0.05). At 60∘/s and 120∘/s, the extensor PT was significantly negatively correlated with SVA and PT (P< 0.05). Trunk extensor strength is significantly lower in DSD patients than in normal controls. The decline in trunk extensor strength in DSD patients is a type of local muscle dysfunction more closely related to the deformity, which is likely involved in the compensatory mechanism of DSD and may reflect the overall imbalance of the trunk.

Compensation Characteristics of Spinal Sagittal Malalignment According to Pelvic Incidence in Elderly Patients with Degenerative Lumbar Spinal Stenosis.

Compensation characteristics of spinal sagittal malalignment according to pelvic incidence (PI) have yet to be elucidated. This study aimed to investigate the difference in compensatory segments according to PI in elderly patients with degenerative lumbar spinal stenosis (DLSS). This retrospective study included 196 patients (143 females, 53 males) suffering from DLSS with an average age of 66.73 years in our department. Sagittal parameters were obtained on the whole spinal lateral radiograph, including T1-T12 slope (T1S-T12S), Cobb angle (CA) of the functional units of the thoracic spine, thoracic kyphosis (TK), lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT), PI, the ratio of PT to PI (PT/PI), PI minus LL mismatch (PI-LL), sagittal vertical axis (SVA). Patients were divided into the low and high PI groups according to the median value of PI. With reference to the value of SVA and PI-LL, each PI group was further grouped into the balance subgroup (SVA < 50 mm, PI-LL ≤10°), hidden imbalance subgroup (SVA < 50 mm, PI-LL > 10°), and imbalance subgroup (SVA ≥50 mm). Independent samples t-test/Mann-Whitney U test, one-way ANOVA/Kruskal-Wallis test, and Person correlation analysis were utilized for statistical test. The median value of PI was 47.65°. 96 and 100 patients were assigned to low and high PI groups, respectively. Correlation analysis indicated that the T8-T12 slope and T10-T12 slope were associated with PI-LL in the high and low PI groups, respectively (all, p < 0.01). For segmental lordosis, T8-9 to T11-12 CA and T10-11 to T11-12 CA were associated with PI-LL in the high and low PI groups, respectively (all, p < 0.01). In the high PI cohort, T8-12 CA and PT increased significantly from the balance to imbalance subgroups (both, p < 0.05). In the low PI cohort, T10-12 CA and PT first increased and then decreased from the balance to imbalance subgroups (both, p < 0.05). T8-12 was the main compensatory segment of the thoracic spine in patients with high PI, while it was T10-12 in patients with low PI. In addition, the compensation potential of the lower thoracic spine and pelvis in patients with low PI was inferior to those with high PI.

Development of a sacral fracture model to demonstrate effects on sagittal alignment.

To develop a modeling framework to predict the secondary consequences on spinal alignment following correction and to demonstrate the impact of pedicle subtraction osteotomy (PSO) location on sagittal alignment. Six patients were included, and pelvic incidence (PI) was measured. Full-length standing radiographs were uploaded into PowerPoint and manipulated to model S1-S2 joint line sacral fractures at 15°, 20°, 25°, and 30°. PSO corrections with hinge points at the anterior superior corner and vertical midpoint of the L3-5 vertebral bodies were modeled. Anterior translation (AT) and vertical shortening (VS) were calculated for the six PSO locations in the four fracture angle (FA) models. PI had a strong effect in the mixed AT and VS models (P < 0.001). Both AT and VS were significantly different from zero at all FA (p < 0.001), and pairwise comparisons revealed all FA were different from each other with respect to both AT and VS after adjusting for PSO location (p < 0.001), increasing as FA increased. Varying PSO location resulted in significant differences in AT when comparing all locations (p < 0.001). AT was greatest for all FA in all patients when the PSO correction was performed at the L3-AS (p < 0.001). There were significant differences in VS when comparing the L5-Mid PSO location to the L3-AS, L3-Mid, L4-AS, and L4-Mid PSO locations (p < 0.034). PSO correction superior to a sacral fracture resulted in AT and VS of the spine. It is crucial that these changes in spinal measures be predicted and accounted for to optimize patient sagittal alignment and outcomes.

MINIMALLY INVASIVE SPINE SURGERY FOR POST-TRAUMATIC KYPHOSIS: A SYSTEMIC LITERATURE REVIEW AND RETROSPECTIVE CASE ANALYSIS

Study Design: Retrospective case analysis and systematic literature review. Objective: To comprehensively review minimally invasive surgery (MIS) for post-traumatic kyphosis. Methods: A systematic PubMed search was conducted for MIS and kyphotic deformities were published between 2012 and 2022. Sixteen patients between 2017 and 2021 met the criteria. Demographic data, surgical characteristics, and full-length radiographic parameters were collected pre- and post-operatively, and at final follow-up. Results: Twenty-three articles were included. The mean age was 67 years, and the mean follow-up was 17 months. The mean operative time was 331 min and blood loss was 252 ml. Pre-operative radiographic outcomes were as follows: Lumbar lordosis (LL), 16.84± 26.40[Formula: see text]; pelvic incidence (PI), 48.95± 14.34[Formula: see text]; PI-LL mismatch, 32.11± 31.92[Formula: see text]; pelvic tilt (PT), 32.74± 10.41[Formula: see text]; and sagittal vertical axis (SVA), 95.33± 59.62 mm. At the final follow-up, LL was 19.98± 16.16[Formula: see text] ([Formula: see text] = 0.51229), PI was 50.82± 10.19[Formula: see text] ([Formula: see text] = 0.61438), PI-LL mismatch was 30.84± 17.18[Formula: see text] ([Formula: see text] = 0.74696), PT was 27.14± 10.28[Formula: see text] ([Formula: see text] = 0.00386), and SVA was 49.73± 25.51 mm ( [Formula: see text] = 0.00465). The mean ODI and VAS scores for back pain at baseline and at 96 months follow-up were 33.2–19.7 and 8.4–2.5, respectively. Conclusion: Age-adjusted MIS provides correction of sagittal alignment for posttraumatic kyphosis that satisfies patient demand.

Comparative Study for Characteristics of Locomotive Syndrome in Patients with Lumbar Stenosis and Adult Spinal Deformity.

The differential diagnoses of lumbar spinal stenosis (LSS) and adult spinal deformity (ASD) have been demonstrated primarily using sagittal radiographic spinopelvic parameters. However, it is more important to know the differences in the characteristic clinical symptoms to make accurate treatment decisions. Recently, the relationship between spinal disease and Locomotive Syndrome (LS) has been reported. Additionally, the Geriatric Locomotive Function Scale-25 (GLFS-25) was reported to be a useful scale to evaluate disease severity and characteristic clinical symptoms in spinal disease. Sixty-nine consecutive patients with ASD and 196 patients with LSS who underwent spinal surgery were included. Locomotive dysfunction was evaluated using the GLFS-25 questionnaire and physical performance tests including the two-step test and the stand-up test, measured preoperatively. The correlations between sagittal spinopelvic parameters of ASD and LS were examined. All subjects with lumbar degenerative disease in the present study were diagnosed with LS preoperatively. The severity of LS in patients with LSS and ASD were statistically similar. GLFS-25 scores in the mobility and community domain were similarly poor in both groups. Several scores in the domestic life and self-care domains were significantly worse in the ASD group. Question 20 of the GLFS-25, related to load-bearing tasks and housework, was significantly associated with a large pelvic incidence in ASD patients. Lumbar degenerative disease requiring surgery severely affects the LS of older people. ASD patients had more difficulty with load-bearing tasks and housework such as cleaning the yard, carrying heavy bedding, dressing, and bathing compared to LSS patients.

Association between posterior tibial slope and anatomic spinopelvic parameters: a retrospective cross-sectional study

PurposeOnly a few publications considered the influence of the spinopelvic parameters on below-hip anatomy. There is a lack of evidence about the relationship between the anatomic spinopelvic parameters and the posterior tibial slope (PTS). Therefore, the aim of this study was to analyze the association between fixed anatomic spinopelvic parameters and PTS.MethodsAdult patients presenting with lumbar, thoracic, or cervical complaints together with knee pain at a single hospital between 2017 to 2022 with available standing full-spine lateral radiograph and lateral knee radiograph were retrospectively reviewed. The measured parameters included the pelvic incidence (PI), the sacral kyphosis (SK), the pelvisacral angle, the sacral anatomic orientation (SAO), the sacral table angle, the sacropelvic angle and the PTS. Pearson’s correlations and linear regression analyses were conducted.ResultsA total of 80 patients (44 women), median age 63 years were analyzed. A strong positive correlation was identified between PI and PTS (r = 0.70, p < 0.001). A strong negative correlation was observed between PI and SAO (r = − 0.74, p < 0.001). A strong positive correlation was observed between PI and SK (r = 0.81, p < 0.001). A univariable linear regression analysis showed that PTS can be deduced from PI according to the following formula: PTS = 0.174 × PI − 1.138.ConclusionThis study is the first to support a positive correlation between the PI and the PTS. We demonstrate that knee anatomy is individually correlated to pelvic shape and therefore influences spinal posture.

Letter to the Editor Regarding "Can Pelvic Incidence Change After Lumbo-Pelvic Fixation for Adult Spine Deformity and Would the Change be Affected by the Type of Pelvic Fixation?"

Letter to the Editor Regarding "Can Pelvic Incidence Change After Lumbo-Pelvic Fixation for Adult Spine Deformity and Would the Change be Affected by the Type of Pelvic Fixation?"

Scoliosis risk factors and outcomes in children with dysplastic spondylolisthesis undergoing surgical reduction and fixation.

To explore scoliosis risk factors and outcomes in children with dysplastic spondylolisthesis undergoing surgical reduction and internal fixation. We retrospectively analyzed 56 children with dysplastic spondylolisthesis who underwent surgical reduction and internal fixation. Patients were grouped according to presence of scoliosis before surgery. Radiographic parameters measured before surgery included pelvic incidence, pelvic tilt, sacral slope, coronal Cobb angle, slip percentage, Dubousset's lumbosacral angle, lumbar lordosis, sagittal vertical axis, and Spinal Deformity Study Group index. Groups were compared using logistic regression. Receiver operating characteristic analysis was performed to determine the optimal Spinal Deformity Study Group index cut-off value. All patients were followed up for at least 2 years. The scoliosis group comprises 36 patients (mean age: 9.6 ± 2.7 years), while the no scoliosis group comprises 20 (mean age: 9.1 ± 2.4 years). Slip percentage and Spinal Deformity Study Group index were significantly higher in the scoliosis group (p < 0.01). Sacral slope and pelvic incidence were lower in the scoliosis group (p < 0.05). Univariate logistic regression analysis showed that slip percentage, Spinal Deformity Study Group index, pelvic incidence, and sacral slope were significantly associated with scoliosis. In the multivariate logistic regression analysis, only Spinal Deformity Study Group index was an independent risk factor for scoliosis. The optimal cut-off value for Spinal Deformity Study Group index was 0.288. Mean Cobb angle decreased from 20.3° ± 8.8° before surgery to 8.5° ± 8.9° at last follow-up; the mean scoliosis correction rate was 59.3%. Severe S1 dysplasia and high slip percentage may be risk factors for developing scoliosis in patients with dysplastic spondylolisthesis. Scoliosis resolved spontaneously after spondylolisthesis reduction and fixation in most patients. 3.

Association of Various Spinopelvic Parameters and the Quality of Life in Those With Degenerative Lumbar Scoliosis in the Indian Population.

Purpose The current study aimed to find any association between various spinopelvic parameters and the quality of life in patients with degenerative lumbar scoliosis (DLS) measured as per the Oswestry disability index (ODI) and visual analog scale (VAS) in the Indian population. Methods We included 20 DLS patients of more than 40 years with a Cobb angle of more than 10° and without any trauma, tumour, infection, or congenital scoliosis presented in our tertiary care centre in the study. The VAS and ODI were calculated for each patient. Radiological parameters were recorded for every patient, including sagittal balance, coronal balance, Cobb angle, pelvic incidence, pelvic tilt, and lumbar lordotic angle. We evaluated the results and sought any association between clinical and radiological variables for DLS. Results Patients with positive sagittal balance had significantly higher disability than those with neutral sagittal balance (p-value 0.007). Furthermore, patients with coronal imbalance had more severe pain (p-value 0.013) and disability (p-value 0.038) than those with neutral coronal balance. We also found that the ODI and VAS were not associated with any other spinopelvic parameters. Conclusion From the present study, we can conclude that in the Indian population, both positive sagittal and coronal imbalances are associated with poor functional status in patients with DLS. Therefore, while planning surgical correction for these patients, both coronal and sagittal balance are important and need to be considered.

Lumbosacral fusion increases the risk of hip osteoarthritis

ObjectiveThere may be biomechanical changes in the adjacent hip joint after lumbosacral fusion. The literature has limited information on how these biomechanical changes may result in hip joint space.MaterialmethodOur retrospective study examined hip joint space narrowing in patients who underwent lumbosacral fusion between 2020 and 2022. In addition, spinopelvic parameters such as sacral slope, the sagittal vertical axis, pelvic incidence, lumbar lordosis, and pelvic tilt were compared in patients who underwent short-segment (up to three levels, S group) and long-segment (4 and higher levels, L group) fusions.ResultsOur study found no significant relationship between spinopelvic parameters and joint space narrowing in the S and L groups. In addition, it was determined that there was more narrowing in the hip joint space in the long-segment group, and there was a positive correlation between the segment length and the narrowing in the hip joint space.ConclusionAfter lumbosacral fusion, narrowing of the hip joint space was observed. Particularly patients with long-segment lumbosacral fusion should be followed closely regarding hip osteoarthritis risk.

Age, pelvic incidence, facet joint angle and pedicle-facet angle as correlative factors for isthmic spondylolisthesis: a retrospective case control study

BackgroundIsthmic spondylolisthesis (IS) is a common clinical disease with a high incidence rate. However, most current researches explain the clear pathogenesis from a single perspective. The aim of our study was to explore the relationships between multiple parameters in patients and find the potential risk factors of this disease.MethodsOur study retrospectively included 115 patients who were diagnosed with isthmic spondylolisthesis and the same number of individuals without spondylolisthesis. The following parameters were measured or collected: age, pelvic incidence (PI), facet joint angle (FJA) and pedicle-facet angle (P-F angle). The radiographic files were imported into Mimics Medical 20.0 and all collected data were analyzed using SPSS, version 26.0, statistical software.ResultsThe age was higher in IS group than in control group. PI was also higher in the IS group (50.99 ± 7.67) than in the control group (43.77 ± 9.30) significantly (P = 0.009). There was significant difference in cranial and average FJA tropism in L3-L4 level (P = 0.002, P = 0.006, respectively) and in L4-L5 level (P < 0.001). P-F angle of L4-L5 level showed significantly larger in IS group than in control group (P = 0.007).The logistic regression analysis showed a larger age, a greater L3-L4 cranial FJA tropism, and a greater L4-L5 cranial FJA tropism were potential predictors of IS, with an OR of 1.07, 1.28, and 1.39 respectively. The thresholds of the predictors were 60 years, 5.67°, and 8.97° according to the ROC curve. The linear regression equation was established: degree of slippage (%) = 0.220*age − 0.327* L3-4 cranial FJA tropism − 0.346* L4-5 average FJA tropism (F = 3.460, P = 0.011, r = 0.659).ConclusionsOur study revealed that isthmic spondylolisthesis may be related to multiple factors rather than a single factor. Age, PI, PJA and P-F angle are potentially associated with spondylolisthesis.

How Do Spinal Parameters Change in Patients Who Have Improvement of Low Back Pain After Total Hip Arthroplasty? A Propensity Score–Matched Cohort Study

BackgroundMany studies have demonstrated that low back pain (LBP) improves after total hip arthroplasty (THA). However, the mechanism underlying this improvement remains unclear. We aimed to investigate changes in the spinal parameters of patients who had LBP improvement after THA to elucidate the mechanism of LBP improvement. MethodsWe included 261 patients who underwent primary THA between December 2015 and June 2021 and had a preoperative visual analog scale score of ≥ 2 for LBP. The patients were classified into the LBP-improved or LBP-continued groups based on the visual analog scale for LBP at 1 year after THA. Preoperative and postoperative changes in the coronal and sagittal spinal parameters were compared between the 2 groups after propensity score matching for age, sex, body mass index, and preoperative spinal parameters. ResultsA total of 161 patients (61.7%) were classified into the LBP-improved group. After 85 patients in both groups were matched, the LBP-improved group showed significant differences in spinal parameter changes, which were a higher lumbar lordosis (LL) (P = .04) and lower sagittal vertical axis (SVA) (P = .02) and pelvic incidence (PI) minus LL (PI-LL) (P = .01) postoperatively, whereas the LBP-continued group showed worsened changes in LL and SVA and PI-LL mismatch. ConclusionPatients who had LBP improvement after THA had significant differences in spinal parameter changes in LL, SVA, and PI-LL. These spinal parameters may be the key factors in the mechanism of LBP improvement after THA.

Functional outcomes correlate with sagittal spinal balance in degenerative lumbar spondylolisthesis surgery

BACKGROUND CONTEXTDegenerative lumbar spondylolisthesis (DLS) is a debilitating condition associated with poor preoperative functional status. Surgical intervention has been shown to improve functional outcomes in this population though the optimal surgical procedure remains controversial. The importance of maintaining and/or improving sagittal and pelvic spinal balance parameters has received increasing interest in the recent DLS literature. However, little is known about the radiographic parameters most associated with improved functional outcomes among patients undergoing surgery for DLS. PURPOSETo identify the effect of postoperative sagittal spinal alignment on functional outcome after DLS surgery. STUDY DESIGNRetrospective cohort study. PATIENT SAMPLETwo-hundred forty-three patients in the Canadian Spine Outcomes and Research Network (CSORN) prospective DLS study database. OUTCOME MEASURESBaseline and 1-year postoperative leg and back pain on the 10-point Numeric Rating Scale and baseline and 1-year postoperative disability on the Oswestry Disability Index (ODI). METHODSAll enrolled study patients had a DLS diagnosis and underwent decompression in isolation or with posterolateral or interbody fusion. Global and regional radiographic alignment parameters were measured at baseline and 1-year postoperatively including sagittal vertical axis (SVA), pelvic incidence and lumbar lordosis (LL). Both univariate and multiple linear regression was used to assess for the association between radiographic parameters and patient-reported functional outcomes with adjustment for possible confounding baseline patient factors. RESULTSTwo-hundred forty-three patients were available for analysis. Among participants, the mean age was 66 with 63% (153/243) female with the primary surgical indication of neurogenic claudication in 197/243 (81%) of patients. Worse pelvic incidence-LL mismatch was correlated with more severe disability [ODI, 0.134, p<.05), worse leg pain (0.143, p<.05) and worse back pain (0.189, p<.001) 1-year postoperatively. These associations were maintained after adjusting for age, BMI, gender, and preoperative presence of depression (ODI, R2 0.179, β, 0.25, 95% CI 0.08, 0.42, p=.004; back pain R2 0.152 (β, 0.05, 95% CI 0.022, 0.07, p<.001; leg pain score R2 0.059, β, 0.04, 95% CI 0.008, 0.07, p=.014). Likewise, reduction of LL was associated with worse disability (ODI, R2 0.168, β, 0.04, 95% CI -0.39, -0.02, p=.027) and worse back pain (R2 0.135, β, -0.04, 95% CI -0.06, -0.01, p=.007). Worsened SVA correlated with worse patient reported functional outcomes (ODI, R2 0.236, β, 0.12, 95% CI 0.05, 0.20, p=.001). Similarly, an increase (worsening) in SVA resulted in a worse NRS back pain (R2 0.136, β, 0.01, 95% CI .001, 0.02, p=.029) and worse NRS leg pain (R2 0.065, β, 0.02, 95% CI 0.002, 0.02, p=.018) scores regardless of surgery type. CONCLUSIONSPreoperative emphasis on regional and global spinal alignment parameters should be considered in order to optimize functional outcome in lumbar degenerative spondylolisthesis treatment.

Impact of Individual Spinopelvic Anatomy on the Localization and Severity of Symptomatic Isthmic Spondylolisthesis.

Retrospective analysis of prospectively collected data. Isthmic spondylolisthesis (iSPL) occurs most commonly in L5/S1 and L4/5. This study investigates the association between spinopelvic anatomy and the pathogenesis of iSPL. Spinopelvic parameters as well as severity of slip grade were measured in sagittal spine radiographs of symptomatic patients with iSPL in segments L4/5 and L5/S1. Means were calculated and differences between both groups were analyzed. A correlation between the analyzed parameters and degree of slippage was performed. We included 73 subjects in this study; 11 in L4/5 group and 62 in L5/S1 group. Pelvic anatomy significantly differed between L4/5 and L5/S1 iSPL (Pelvic Incidence (PI) 54.8° vs 66.3°, P value = .006; Pelvic Radius (PR) 124.4mm vs 137.4mm; P value = .005 and Sacral Table Angle (STA) 101.0° vs 92.2°, P value < .001). The relative degree of slippage was significantly higher in the L5/S1 group (L4/5 29.1% vs L5/S1 40.1%, P value .022). We also observed a significant correlation between pelvic anatomy and the severity of the slip in iSPL at the L5/S1 level. Pelvic parameters PI and STA play an important role concerning the level of occurrence and severity of iSPL. Spinopelvic anatomy determines the pathogenesis of iSPL.

Can placement of hook at the upper instrumented level decrease the proximal junctional kyphosis risk in adolescent idiopathic scoliosis?

Proximal junctional kyphosis is a commonly encountered clinical and radiographic phenomenon after pediatric and adolescent spinal deformity surgery that may lead to postoperative deformity, pain, and dissatisfaction. The purpose of the study was to identify whether the placement of transverse process hooks is an effective way to prevent PJK. Adolescent idiopathic scoliosis patients who underwent posterior spinal fusion between November 2015 and May 2019 were retrospectively analyzed. A minimum 2-year follow-up was required. Demographic and surgical data included UIV level type of instrumentation (hook vs screw) were reported. Radiologic parameters included main curve Cobb angle, thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), and proximal junctional angle (PJA) were assessed. Patients were divided into two groups based on the type of instrumentation at the UIV level whether placement of hook versus pedicle screw. Three hundred and thirty-seven patients were included with the mean age 14.2 ± 1.9years. Thirty patients (8.9%) were diagnosed with proximal junctional kyphosis radiographically. PJK incidence was found 3.2% (5/154) in the hook group and 13.3% (23/172) in the screw group and the difference found statistically significant. In the PJK group, preoperative thoracic kyphosis and the degree of kyphosis correction were also significantly higher than non-PJK patients. Placement of transverse process hooks at the UIV level in posterior spinal fusion surgery for AIS patients was associated with decreased risk of PJK. A larger preoperative kyphosis and greater degree of kyphosis correction correlated with PJK.

Sagittal Spinopelvic Alignment in the Standing and Prone Positions of Patients with Old Traumatic Thoracolumbar Kyphosis: Relationship with Immediately Postoperative Parameters

The aim of this study was to investigate the changes in spine-pelvis sagittal parameters from the standing position to the prone position and to study the relationship between sagittal parameters and immediately postoperative parameters. Thirty-six patients with old traumatic spinal fracture combined with kyphosis were enrolled. The preoperative standing position, prone position and postoperative sagittal parameters of the spine and pelvis, including the local kyphosis Cobb angle (LKCA), thoracic kyphosis angle (TK), lumbar lordosis angle (LL), sacral slope (SS), pelvic tilt (PT), pelvic incidence minus lumbar lordosis angle (PI-LL), and sagittal vertebral axis (SVA), were measured. The data of kyphotic flexibility and correction rate was collected and analyzed. The parameters of the preoperative standing position, prone position and postoperative sagittal position were analyzed statistically. Correlation analysis and regression analysis of the preoperative standing and prone sagittal parameters and postoperative parameters were conducted. There were significant differences in the preoperative standing position, prone position and postoperative LKCA and TK. Correlation analysis showed that preoperative sagittal parameters of the standing position and prone position were all correlated with postoperative homogeneity. Flexibility was not related to the correction rate. Regression analysis showed preoperative standing, prone LKCA, and TK were linear with postoperative. The LKCA and TK of old traumatic kyphosis obviously changed from the standing position to the prone position, which were linear with postoperative LKCA and TK and can be used to predict postoperative sagittal parameters. This change should be taken into account in the surgical strategy.

Evaluating the Changes in Sagittal Balance via EOS Imaging before and after Total Hip Arthroplasty

Background and Aim: Sagittal imbalance is often presented as one of the major problems in individuals suffering from orthopedic pain, particularly those affected by destructive hip joint osteoarthritis. In this regard, total hip arthroplasty (THA) as a therapeutic procedure for such patients has resulted in the restoration of sagittal balance. Therefore, the present study aimed to evaluate the changes in sagittal balance using EOS imaging before and after THA and also reflect on its effect on hip joint function, knee pain, and disability percentage due to low back pain (LBP). Methods: Utilizing a prospective cohort study, a total number of 24 patients suffering from extreme unilateral hip osteoarthritis and in need of unilateral THA were selected based on the inclusion and exclusion criteria, and then, sagittal balance parameters, including pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), sacrofemoral angle (SFA), sacrofemoral distance (SFD), lumbar lordosis (LL), and stem angle (SA) were investigated after performing standing radiographs by means of the EOS device. One year after THA, all the above-mentioned parameters were also measured by EOS imaging before and after the surgery and the patients completed some questionnaires, which is the Oswestry Low Back Pain Disability Index (OLBPDI) to evaluate disability percentage resulting in LBP, the Knee Injury and Osteoarthritis Outcome Score (KOOS) instrument to assess knee pain, and the Harris Hip Score (HHS) measure to rate hip joint function, and then the results were analyzed using the SPSS Statistics software (ver. 17). Results: The patients consisted of 13 males (54.2%) and 11 females (45.8%) with the mean age of 52.87±13.05. The mean score of the preoperative PI was also equal to 54.74±10.66 and it was 58.19±11.58 after the surgery (p=0.025). However, the mean values of other parameters at the preoperative stage did not show any significant changes. As well, hip joint function and knee pain resulting from LBP improved in the patients after the surgery (p&lt;0.001). Conclusion: The study findings demonstrated that THA probably influenced sagittal balance through PI. Moreover, the postoperative hip joint function, knee pain, and disability percentage caused by LBP significantly enhanced compared with those before the surgery. Thus, it was concluded that the evaluation of sagittal balance parameters could help patients with orthopedic pain.