Sagittal Alignment Parameters Research Articles

Prevalence of total joint arthroplasty in the adult spine deformity population.

The spine, hip, and knee are anatomically and biomechanically connected. Total hip arthroplasty (THA) and total knee arthroplasty (TKA) are commonly employed to treat degenerative changes in the hip and knee, while fusion is used for spine degeneration. Spine deformity correction results in changes in sagittal alignment and pelvic parameters, and patients with stiff spines have higher rates of THA dislocation and revision due to instability. The goal of this study was to determine the prevalence of total joint arthroplasty (TJA) in adult spinal deformity (ASD) patients at our institution. Following Institutional Review Board approval, we retrospectively reviewed a list of cases performed by the senior author from 4/2017 to 5/2021. Patients > 18years old undergoing preoperative evaluation for symptomatic lumbar degeneration or ASD were included. Patients < 18years old, those diagnosed with adolescent idiopathic scoliosis, and non-fusion cases were excluded. Perioperative full-length standing EOS images were examined for the presence or absence of THA, TKA, or both. Demographic data was collected from patient electronic medical records, and statistical analyses were completed. 572 consecutive cases were reviewed, and 322 were excluded. 250 cases (97M:153F) were included in the final analysis, with a mean age of 61.8 ± 11.2years. A total of 74 patients had a TJA (29.4%). THA was present in 41 patients (16.4%), and TKA was present in 49 patients (19.6%). Males had a higher prevalence of TJA, THA, and TKA (29.9%, 16.5%, and 21.6%) than females (29.4%, 16.3%, and 18.3%). This study revealed a high prevalence TJA rate of 29.4% in ASD at our institution. This rate surpasses the prevalence rate reported among the general population in previous studies. High prevalence of patients with ASD and TJA may merit special surgical consideration.

Does Periacetabular Osteotomy Change Sagittal Spinopelvic Alignment?

There are few data on the impact of periacetabular osteotomy (PAO) on sagittal spinopelvic alignment. Prior studies have attempted to delineate the relationship by performing measurements on AP radiographs and using mathematical models to determine changes in postoperative pelvic tilt. This information is clinically significant to a surgeon when evaluating acetabular/pelvic position intraoperatively and understanding spinopelvic alignment changes postoperatively; therefore, radiographic changes from PAO should be described in more detail. In this study, we asked: (1) Does the performance of PAO result in consistent changes in spinopelvic alignment, as measured on EOS radiographs? (2) Does this differ for unilateral versus bilateral PAOs? (3) Does this differ in the setting of a mobile spine versus an immobile spine? (4) Does this differ based on preoperative pelvic tilt? Mean preoperative and at least 1-year postoperative (15 ± 8 months from surgery, minimum 11 months, maximum 65 months) EOS hip-to-ankle standing and sitting radiographs for 55 patients in a prospectively collected registry who underwent PAO with a single surgeon from January 1, 2019, to January 11, 2022, were measured for pelvic incidence, pelvic tilt, sacral slope, lumbar lordosis, lateral center-edge angle, L1 pelvic angle, and pubic symphysis to the sacroiliac index. Normality was assessed and paired sample t-tests (normally distributed data) or Wilcoxon signed rank tests (not normally distributed data) were utilized to assess if any measurements changed from preoperative to postoperative. Patients were then divided based on whether they had unilateral or bilateral dysplasia and unilateral or bilateral surgery, and these subgroups were analyzed the same way as the entire cohort. Two more subgroups were then formed based on lumbar mobility, defined as a change in sitting-to-standing lumbar lordosis less or greater than 1 SD from the population mean preoperatively, and the subgroups were analyzed the same way as the entire cohort. Finally, two additional subgroups were formed, preoperative standing pelvic tilt less than 10° and more than 20°, and analyzed the same as the entire cohort. For the entire cohort, the median (IQR) standing lateral-center edge angle increased 17°, from a median of 21° (10°) to a median of 38° (8° [95% confidence interval (CI) 16° to 20°; p < 0.001). The median sitting lateral center-edge angle increased 17°, from a median of 18° (8°) to a median of 35° (8° [95% CI 14° to 19°]; p < 0.001). Standing pelvic incidence increased from 50° ± 11° to 52° ± 12° (mean difference 2° [95% CI 1° to 3°]; p = 0.004), but there were no changes for other measured parameters. There were no changes in any of the spinopelvic parameters for patients with unilateral dysplasia receiving a unilateral PAO, but patients with bilateral dysplasia who underwent bilateral PAOs demonstrated an increase in pelvic incidence from 57° (14°) to 60° (16°) (95% CI 1° to 5°; p = 0.02) and a decrease in pubic symphysis to sacroiliac index from 84 mm (24 mm) to 77 mm (23 mm) (95% CI -7° to -2°; p = 0.007). Patients with mobile lumbar spines preoperatively did not exhibit any changes in sagittal spinopelvic alignment, but patients with immobile lumbar spines preoperatively experienced several changes after surgery. Patients with less than 10° of standing pelvic tilt demonstrated a median (IQR) 2° increase in pelvic incidence from median 43° (9°) to 45° (12° [95% CI 0.3° to 4°]; p = 0.03), but they did not experience any other changes in sagittal spinopelvic alignment parameters postoperatively. Patients with preoperative pelvic tilt more than 20° did not experience any change in sagittal spinopelvic parameters. PAO increases pelvic incidence, potentially because of anterior translation of the hip center. There were no changes in other spinopelvic parameters postoperatively except after bilateral PAO. Additionally, patients lacking spine mobility preoperatively, indicated by a minimal change in lumbar lordosis between standing and sitting positions, may experience several changes in spinopelvic alignment, including increased mobility of their spine after PAO. This may be because of decreased compensatory spine splinting after increasing acetabular coverage, but further research including patient-reported outcomes is warranted. Level III, therapeutic study.

Analysis on association between sagittal stem alignment and early functional and radiological outcome following primary cementless total hip replacement.

Accurate reconstruction of hip anatomy and biomechanics is mandatory for achieving good clinical outcomes following total hip replacement (THR). Optimal stem alignment is essential to avoid impingement or loosening. This study aimed to evaluate sagittal stem position following cementless THR and its relationship with patient's functional outcome and post-operative radiological parameters. We performed analytical observational study with cross-sectional design on 71 hips (67 patients, ranged 18-85years old) that underwent primary cementless THR in two orthopedic centers in Jakarta, Indonesia. All hips were operated through either anterolateral or posterior approach using either extended/full-coating wedge-tapered stem or proximal-coated wedge-tapered stem. Clinical outcomes were evaluated at follow-up time using mHHS questionnaire, VAS level of thigh pain, and hip ROM. Stem sagittal alignment and other radiological parameters, including combined anteversion and offset, were measured from conventional radiograph. There were no significant differences on mHHS score, VAS level on thigh pain, and ROM between stem alignment groups. Post-operative anteversion and offset of the implant were not affected by the stem sagittal position. All influencing factors have significant effect on sagittal stem alignment. Linear regression test on femur morphology showed 0.69° increase in stem posterior tilt for every 1° increase in the anterior bowing (coeff. = 0.502). Stem tilting in sagittal plane did not affect patient's functional outcome or post-operative radiological parameters. In addition, for every degree of increased anterior femoral bowing, 0.69° increase in posterior stem tilting can be expected.

1073 Prone Transpsoas (PTP)-LLIF Approach Versus Standard LLIF in Patients Undergoing Surgical Revision Following Adult Spinal Deformity Correction Surgery

INTRODUCTION: Both the prone transpsoas (PTP) and standard LLIF have been developed to facilitate minimally invasive (MIS) indirect decompression, alignment correction, and posterior instrumentation. METHODS: A multi-center cohort of all patients was identified and all relevant data were retrospectively collected. Preoperative standing 36” scoliosis radiographs were retrospectively reviewed for pelvic incidence (PI), lumbar lordosis (LL), and PI minus LL (PI-LL mismatch). Postoperative regional sagittal alignment parameters were measured using the first postoperative standing 36” scoliosis radiographs. Finally, multivariable analysis was performed to assess the primary outcome measure: postoperative change in regional sagittal alignment (PI-LL mismatch). RESULTS: Two-hundred and two (n = 202) patients were retrospectively identified and included for formal analysis. One-hundred and fifty one (n = 151, 74.8%) of the patients underwent PTP revision while 51 (25.2%) underwent standard LLIF revision. Univariate analysis demonstrated a greater value for baseline mean pre-operative PI-LL mismatch in the PTP versus standard LLIF cohort (21.4 vs. 10.45°; p = 0.0001). Furthermore, multiple linear regression demonstrated that the PTP approach enabled significantly greater PI-LL mismatch change (p = 0.0017) and that this change was associated with the number of levels fused (p = 0.0481) as well as percutaneous (vs. open) screw placement (p = 0.0193). Finally, multiple logistic regression identified standard LLIF (p = 0.0378), female sex (p &lt; 0.0001), non-osteoporotic bone density (p &lt; 0.0001), and younger age (p &lt; 0.0001) as predictive of postoperative PI-LL mismatch &lt; 10° (the threshold under which such mismatch is no longer regarded as clinically significant deformity). CONCLUSIONS: Ultimately, PTP-LLIF was associated with greater net improvement in postoperative PI-LL mismatch, the primary outcome measure of this study. The present retrospective analysis therefore corroborated results of previous studies in suggesting that the utility of PTP-LLIF is translatable to ASD revision surgery.

The association of cervical sagittal alignment with anterior bone loss following single-level anterior cervical surgery.

Anterior bone loss (ABL) is a common phenomenon after cervical disc replacement (CDR), which can also be observed after anterior cervical discectomy and fusion (ACDF). This study aimed to investigate the incidence and severity of ABL in single-level CDR and ACDF and explore the association of cervical sagittal alignment with ABL. This is a single-center retrospective cohort study. A total of 113 patients treated with CDR and 99 patients treated with ACDF were retrospectively reviewed from January 2014 to December 2018 in West China Hospital. Radiological data were collected at pre-operation, 1 week, 3 months postoperatively, and the last follow-up. The incidence and severity of ABL after both CDR and ACDF were evaluated. Cervical sagittal alignment parameters, including C0-C2 angle, cervical lordosis (CL), C2-C7 sagittal vertical axis (cSVA), T1 slope, functional spinal unit angle, disc angle, and surgical level slope, were evaluated. ABL was identified in 75 (66.4%) patients in the CDR group and 57 (57.6%) patients in the ACDF group. There were no significant differences in the incidence, severity, and location of ABL between the ACDF and CDR groups. For patients who underwent ACDF, the proportion of females was significantly higher in the ABL group (64.9% vs. 33.3%, P=0.002), whereas the body mass index (BMI) was significantly lower in the ABL group compared to the non-ABL group (22.72±3.09 vs. 24.60±3.04, P=0.002). No effect of ABL on the short-term clinical outcomes of ACDF and CDR was observed. In the ACDF group, patients with ABL had significantly smaller postoperative CL (11.83°±8.24° vs. 15.25°±8.32°, P=0.04) and cSVA (17.77±10.08 vs. 23.35±9.86 mm, P=0.007). In the CDR group, no significant differences were found in the cervical sagittal parameters between patients with and without ABL (CL: 12.58±8.70 vs. 15.46±8.50, P=0.10; cSVA: 20.95±8.54 vs. 19.40±9.43, P=0.38). ABL is common after both CDR and ACDF with comparable incidence and severity. Cervical sagittal alignment was closely related to ABL after ACDF yet had less influence on ABL after CDR.

Costs of revision operations for distal junctional kyphosis following thoracic posterior spinal fusion for adolescent idiopathic scoliosis.

To assess direct costs and risks associated with revision operations for distal junctional kyphosis/failure (DJK) following thoracic posterior spinal instrumented fusions (TPSF) for adolescent idiopathic scoliosis (AIS). Children who underwent TPSF for AIS by a single surgeon (2014-2020) were reviewed. Inclusion criteria were minimum follow-up of 2years, thoracolumbar posterior instrumented fusion with a lower instrumented vertebra (LIV) cranial to L2. Patients who developed DJK requiring revision operations were identified and compared with those who did not develop DJK. Seventy-nine children were included for analysis. Of these, 6.3% developed DJK. Average time to revision was 20.8 ± 16.2months. Comparing index operations, children who developed DJK had significantly greater BMIs, significantly lower thoracic kyphosis postoperatively, greater post-operative lumbar Cobb angles, and significantly more LIVs cranial to the sagittal stable vertebrae (SSV), despite having statistically similar pre-operative coronal and sagittal alignment parameters and operative details compared with non-DJK patients. Revision operations for DJK, when compared with index operations, involved significantly fewer levels, longer operative times, greater blood loss, and longer hospital lengths of stay. These factors resulted in significantly greater direct costs for revision operations for DJK ($76,883 v. $46,595; p < 0.01). In this single-center experience, risk factors for development of DJK were greater BMI, lower post-operative thoracic kyphosis, and LIV cranial to SSV. As revision operations for DJK were significantly more costly than index operations, all efforts should be aimed at strategies to prevent DJK in the AIS population.

A Preliminary Diagnostic Model for Forward Head Posture among Adolescents Using Forward Neck Tilt Angle and Radiographic Sagittal Alignment Parameters.

Despite numerous attempts to correct forward head posture (FHP), definitive evidence-based screening and diagnostic methods remain elusive. This study proposes a preliminary diagnostic methodology for FHP, utilizing a noninvasive body angle measurement system as a screening test for FHP and incorporating radiological parameters for sagittal alignment. We enrolled 145 adolescents for FHP screening. The forward neck tilt angle (FNTA), defined as the angle between the vertical line and the line connecting the participant's acromion and tragus, was measured using the POM-Checker (a noninvasive depth sensor-based body angle measurement system). A whole-spine standing lateral radiograph was obtained, and eight sagittal alignment parameters were measured. Statistical analyses of the association between the FNTA and eight sagittal alignment parameters were conducted. We used 70% of the participant data to establish a preliminary diagnostic model for FHP based on FNTA and each sagittal alignment parameter. The accuracy of the model was evaluated using the remaining 30% of the participant data. All radiological parameters of sagittal alignment showed weak statistical significance with respect to FNTA (best case: r = 0.16, p = 0.0500; cranial tilt). The proposed preliminary diagnostic model for FHP demonstrated 95.35% agreement. Notably, the model using FNTA without radiological parameters accurately identified (100%) participants who required radiographic scanning for FHP diagnosis. Owing to the weak statistical significance of the association between radiological parameters and external body angle, both factors must be considered for accurate FHP diagnosis. When a clear and severe angle variation is observed in an external body angle check, medical professionals should perform radiographic scanning for an accurate FHP diagnosis. In conclusion, FNTA assessment of FNTA through the proposed preliminary diagnostic model is a significant screening factor for selecting participants who must undergo radiographic scanning so that a diagnosis of FHP can be obtained.

Assessment of a fully-parametric thoraco-lumbar spine model generator with articulated ribcage

The present paper describes a novel user-friendly fully-parametric thoraco-lumbar spine CAD model generator including the ribcage, based on 22 independent parameters (1 posterior vertebral body height per vertebra + 4 sagittal alignment parameters, namely pelvic incidence, sacral slope, L1-L5 lumbar lordosis, and T1-T12 thoracic kyphosis). Reliable third-order polynomial regression equations were implemented in Solidworks to analytically calculate 56 morphological dependent parameters and to automatically generate the spine CAD model based on primitive geometrical features. A standard spine CAD model, representing the case-study of an average healthy adult, was then created and positively assessed in terms of spinal anatomy, ribcage morphology, and sagittal profile.The immediate translation from CAD to FEM for relevant biomechanical analyses was successfully demonstrated, first, importing the CAD model into Abaqus, and then, iteratively calibrating the constitutive parameters of one lumbar and three thoracic FSUs, with particular interest on the hyperelastic material properties of the IVD, and the spinal and costo-vertebral ligaments.The credibility of the resulting lumbo-sacral and thoracic spine FEM with/without ribcage were assessed and validated throughout comparison with extensive in vitro and in vivo data both in terms of kinematics (range of motion) and dynamics (intradiscal pressure) either collected under pure bending moments and complex loading conditions (bending moments + axial compressive force).

Clinical and Radiologic Analysis of Minimally Invasive Anterior-Posterior Combined Surgery for Adult Spinal Deformity: Comparison of Oblique Lateral Interbody Fusion at L5/S1 (OLIF51) versus Transforaminal Interbody Fusion.

Background and Objectives: Although adult spinal deformity (ASD) surgery brought about improvement in the quality of life of patients, it is accompanied by high invasiveness and several complications. Specifically, mechanical complications of rod fracture, instrumentation failures, and pseudarthrosis are still unsolved issues. To better improve these problems, oblique lateral interbody fusion at L5/S1 (OLIF51) was introduced in 2015 at my institution. The objective of this study was to compare the clinical and radiologic outcomes of anterior-posterior combined surgery for ASD between the use of OLIF51 and transforaminal interbody fusion (TLIF) at L5/S1. Materials and Methods: A total of 117 ASD patients received anterior-posterior correction surgeries either with the use of OLIF51 (35 patients) or L5/S1 TLIF (82 patients). In both groups, L1-5 OLIF and minimally invasive posterior procedures of hybrid or circumferential MIS were employed. The sagittal and coronal spinal alignment and spino-pelvic parameters were recorded preoperatively and at follow-up. The quality-of-life parameters and visual analogue scale were evaluated, as well as surgical complications at follow-up. Results: The average follow-up period was thirty months (13-84). The number of average fused segments was eight (4-12). The operation time and estimated blood loss were significantly lower in OLIF51 than in TLIF. The PI-LL mismatch, LLL, L5/S1 segmental lordosis, and L5 coronal tilt were significantly better in OLIF51 than TLIF. The complication rate was statistically equivalent between the two groups. Conclusions: The introduction of OLIF51 for adult spine deformity surgery led to a decrease in operation time and estimated blood loss, as well as improvement in sagittal and coronal correction compared to TLIF. The circumferential MIS correction and fusion with OLIF51 serve as an effective surgical modality which can be applied to many cases of adult spinal deformity.

Risk factors of instrumentation failure after laminectomy and posterior cervical fusions (PCF)

BackgroundFor patients with multilevel degenerative cervical myelopathy, laminectomy and posterior cervical fusions (PCF) with instrumentation are widely accepted techniques for symptom relief. However, hardware failure is not rare and results in neck pain or even permanent neurological lesions. There are no in-depth studies of hardware-related complications following laminectomy and PCF with instrumentation.MethodsThe present study was a retrospective, single centre, observational study. Patients who underwent laminectomy and PCF with instrumentation in a single institution between January 2019 and January 2021 were included. Patients were divided into hardware failure and no hardware failure group according to whether there was a hardware failure. Data, including sex, age, screw density, end vertebra (C7 or T1), cervical sagittal alignment parameters (C2-C7 cervical lordosis, C2-C7 sagittal vertical axis, T1 slope, Cervical lordosis correction), regional Hounsfield units (HU) of the screw trajectory and osteoporosis status, were collected and compared between the two groups.ResultsWe analysed the clinical data of 56 patients in total. The mean overall follow-up duration was 20.6 months (range, 12–30 months). Patients were divided into the hardware failure group (n = 14) and no hardware failure group (n = 42). There were no significant differences in the general information (age, sex, follow-up period) of patients between the two groups. The differences in fusion rate, fixation levels, and screw density between the two groups were not statistically significant (p > 0.05). The failure rate of fixation ending at T1 was lower than that at C7 (9% vs. 36.3%) (p = 0.019). The regional HU values of the pedicle screw (PS) and lateral mass screw (LMS) in the failure group were lower than those in the no failure group (PS: 267 ± 45 vs. 368 ± 43, p = 0.001; LMS: 308 ± 53 vs. 412 ± 41, p = 0.001). The sagittal alignment parameters did not show significant differences between the two groups before surgery or at the final follow-up (p > 0.05). The hardware failure rate in patients without osteoporosis was lower than that in patients with osteoporosis (14.3% vs. 57.1%) (p = 0.001).ConclusionsOsteoporosis, fixation ending at C7, and low regional HU value of the screw trajectory were the independent risk factors of hardware failure after laminectomy and PCF. Future studies should illuminate if preventive measures targeting these factors can help reduce hardware failure and identified more risk factors, and perform long-term follow-up.

Association Between Cervical Sagittal Alignment and Subaxial Paraspinal Muscle Parameters.

Retrospective review of prospectively collected data. The authors aim to investigate the association between muscle functional group characteristics and sagittal alignment parameters in patients undergoing anterior cervical discectomy and fusion. The relationship between the morphology of cervical paraspinal muscles and sagittal alignment is not well understood. Patients with preoperative cervical magnetic resonance imaging and cervical spine lateral radiographs in standing position who underwent anterior cervical discectomy and fusion between 2015 and 2018 were reviewed. Radiographic alignment parameters included C2 to 7 lordosis, C2 to 7 sagittal vertical axis (SVA), C2 slope, neck tilt, T1 slope, and thoracic inlet angle. Muscles from C3 to C7 were categorized into four functional groups: sternocleidomastoid group, anterior group, posteromedial group, and posterolateral group (PL). A custom-written Matlab software was used to assess the functional cross-sectional area (fCSA) and percent fat infiltration (FI) for all groups. Multivariable linear regression analyses were conducted and adjusted for age, sex, and body mass index. A total of 172 patients were included. Regression analyses demonstrated that a greater C2 to 7 SVA was significantly associated with a greater FI of the anterior group from C3 to C5 and with a higher fCSA of the PL group at C3 to C4, and C6 to 7. A larger C2 slope was significantly correlated with a greater FI of the anterior group at C3 to C4 and a higher fCSA of the PL group from C3 to C5. This work proposes new insights into the complex interaction between sagittal alignment and cervical paraspinal muscles by emphasizing the importance of these muscles in sagittal alignment. The authors hypothesize that with cervical degeneration, the stabilizing function of the anterior muscles decreases, which may result in an increase in the compensatory mechanism of the PL muscles. Consequently, there may be a corresponding increase in the C2 to C7 SVA and a larger C2 slope.

Comparison of the effectiveness of zero-profile device and plate cage construct in the treatment of one-level cervical disc degenerative disease combined with moderate to severe paraspinal muscle degeneration.

Recent evidence indicates that cervical paraspinal muscle degeneration (PMD) is a prevalent and age-related condition in patients with cervical disc degenerative disease (CDDD). However, the relationship between surgery selection and post-operative outcomes in this population remains unclear. Consequently, this study aims to investigate the disparities in clinical outcomes, radiological findings, and complications between two frequently utilized anterior cervical surgical procedures. The objective is to offer guidance for the management of PMD in conjunction with CDDD. A total of 140 patients who underwent single-level anterior cervical discectomy and fusion (ACDF) at our department were included in this study. The patients were divided into three groups based on the severity of PMD: mild (n=40), moderate (n=54), and severe (n=46), as determined by Goutalier fat infiltration grade. The subjects of interest were those with moderate-severe PMD, and their clinical outcomes, radiological parameters, and complications were compared between those who received a stand-alone zero-profile anchored cage (PREVAIL) and those who received a plate-cage construct (PCC). The JOA, NDI, and VAS scores exhibited significant improvement at all postoperative intervals when compared to baseline, and there were no discernible differences in clinical outcomes between the two groups. While the PCC group demonstrated more pronounced enhancements and maintenance of several sagittal alignment parameters, such as the C2-7 angle, FSU angle, C2-7 SVA, and T1 slope, there were no statistically significant differences between the two groups. The incidence of dysphagia in the zero-profile group was 22.41% at one week, which subsequently decreased to 13.79% at three months and 3.45% at the final follow-up. In contrast, the plate cage group exhibited a higher incidence of dysphagia, with rates of 47.62% at one week, 33.33% at three months, and 11.90% at the final follow-up. Notably, there were significant differences in the incidence of dysphagia between the two groups within the first three months. However, the fusion rate, occurrence of implant subsidence, and adjacent segment degeneration (ASD) were comparable at the final follow-up. For patients with one-level cervical disc degenerative disease combined with paraspinal muscle degeneration, both the zero-profile technique and PCC have demonstrated efficacy in ameliorating clinical symptoms and maintaining the postoperative sagittal balance. Although no significant disparities were observed between these two technologies in terms of complications such as adjacent segment degeneration and implant subsidence, the zero-profile technique exhibited superior performance over PCC in relation to dysphagia during the early stages of postoperative recovery. To validate these findings, studies with longer follow-up periods and evaluations of multilevel cervical muscles are warranted.

Outcome of Decompressive Laminectomy with or without Posterior Screw Fixation for Thoracic Ossification of the Ligamentum Flavum with Disc Degeneration

Objective: Thoracic myelopathy caused by the ossification of the ligamentum flavum (OLF) is commonly treated with surgical decompression. This study aimed to compare the clinical and radiological outcomes of surgical decompression without posterior screw fixation (decompressive laminectomy [DL] group) and with posterior screw fixation (laminectomy with screw fixation [LSF] group) for thoracic myelopathy due to OLF with disc degeneration.Methods: A retrospective review of 35 patients (DL group, n = 19; LSF group, n = 16) was conducted. Clinical variables (Japanese Orthopaedic Association scores) and radiological variables (including sagittal vertical axis, pelvic tilt, thoracic kyphosis, sacral slope, lumbar lordosis (LL), segmental Cobb’s angle, dynamic Cobb’s angle, and dynamic thoracolumbar junction [dTLJ] at the operated level) were measured preoperatively and 1 year postoperatively.Results: Both groups exhibited significant improvements in clinical characteristics postoperatively. LL significantly increased at 1 year postoperatively in both groups. Other sagittal alignment parameters did not change significantly. The dTLJ did not differ significantly between the groups preoperatively; however, the dTLJ of the DL group was larger than that of the LSF group at 1 year postoperatively. There was no significant difference between the groups’ dynamic Cobb’s angles or risk of complications.Conclusion: Decompression surgery for OLF resulted in clinical improvement regardless of whether posterior fixation was performed. Decompression without posterior fixation could allow thoracolumbar motion preservation and might be an effective approach for thoracic OLF with disc degeneration.

Influence of Spinopelvic Alignment on the Clinical Outcomes Following Decompression Surgery for Lumbar Stenosis.

Introduction The role of sagittal spinopelvic alignment in lumbar spinal stenosis (LSS) patients and its potential influence on post-decompression surgery outcomes is a topic of growing interest. Lumbar spinal stenosis is a prevalent degenerative condition, and with an aging population, the frequency of surgical interventions for LSS has risen. While decompression surgery aims to relieve symptoms, the potential impact of preoperative spinopelvic alignment on postoperative results remains controversial. This study examined the correlation between sagittal spinopelvic parameters and clinical outcomes in LSS patients undergoing decompression surgery. Methods This study included 100 patients with LSS who underwent decompression surgery between 2021 and 2023 and 100 healthy individuals as a control group. The LSS group comprised 50 men and 50 women, with a mean age of 55.8±12.41 years, while the control group consisted of 50 men and 50 women, with a mean age of 55.17±13.39 years. Sagittal spinopelvic alignment parameters, including pelvic tilt (PT), pelvic incidence-lumbar lordosis mismatch, and sagittal vertical axis, were assessed preoperatively. Postoperative clinical outcomes were evaluated using the visual analog scale (VAS) and Oswestry disability index (ODI) scores. Results In the cohort of 200 participants, 100 were diagnosed with lumbar spinal stenosis (LSS), and 100 were healthy controls. Both groups had an equal gender distribution (50 males and 50 females). The mean age was 55.8 (±12.4) years for the LSS group and 55.2 (±13.4) years for the control group. Among the analyzed radiographic parameters, only lumbar lordosis (LL) levels showed a significant difference between groups, notably lower in the LSS group (p=0.020). Preoperative VAS scores in LSS patients averaged 7.58±1.32, which postoperatively dropped to 2.22±1.95 (p<0.001). Similarly, ODI (%) declined from a preoperative average of 55.76±11.65 to 18.62±18.17 postoperatively (p<0.001). Patients with postoperative ODI levels exceeding 20% had higher preoperative scores and significantly altered radiographic measurements. The receiver operating characteristic (ROC) analysis indicated PT as the most predictive radiographic parameter, with an area under the curve (AUC) of 0.945. Multivariate logistic regression pinpointed PT and LL as key predictors associated with increased risks for postoperative Oswestry disability levels exceeding 20%. Conclusion Our study suggests that sagittal spinopelvic alignment plays an important role in the development and progression of LSS. Addressing sagittal alignment may be crucial for achieving optimal clinical outcomes afterdecompression surgery. Further research is needed to elucidate the mechanisms underlying the relationship between sagittal alignment and LSS.

Risk factors of postoperative coronal malalignment following long-segment spinal fusion surgery in which multilevel lateral lumbar interbody fusion was used for degenerative lumbar kyphoscoliosis.

In patients with adult spinal deformity, especially degenerative lumbar kyphoscoliosis (DLKS), preoperative sagittal malalignment and coronal malalignment (CM) often coexist. Lateral lumbar interbody fusion (LLIF) has recently been widely chosen for DLKS treatment due to its minimal invasiveness and excellent sagittal alignment correction. However, postoperative CM may remain or occur due to an oblique takeoff phenomenon following multilevel LLIF, resulting in poor clinical outcomes. The authors investigated the risk factors for postoperative CM after long-segment fusion corrective surgery in which multilevel LLIF was used in patients with DLKS. Fifty-four consecutive patients with DLKS, main Cobb angle ≥ 20°, and lumbar lordosis ≤ 20° who underwent corrective spinal fusion surgery, including extreme lateral interbody fusion at ≥ 3 segments, were included at the authors' institute between April 2014 and October 2019. Patients who underwent suitable 3-column osteotomy, classified as grade 3-6 per the Scoliosis Research Society-Schwab criteria, were excluded. Patients were divided into CM and non-CM groups based on postoperative CM evaluated using standard standing-position radiographs obtained 2 years postoperatively. CM was defined as an absolute C7-CSVL (deviation of C7 plumb line off central sacral vertical line; calculated by defining the convex side of the CSVL as positive numerical values) value of ≥ 3.0 cm. Patient demographics and preoperative sagittal alignment parameters were evaluated. The following variables were measured to assess coronal alignment: main Cobb angle; preoperative C7-CSVL; amount of lateral listhesis; L4, L5, and sacral coronal tilt angles; coronal vertebral deformity angles; and coronal spine rigidity. Regarding risk factors for postoperative CM, patient characteristics, preoperative sagittal parameters, and coronal parameters did not significantly differ between the 2 groups, except for preoperative C7-CSVL (p = 0.016). Multivariate logistic regression analysis revealed that preoperative C7-CSVL (+1 cm; OR 1.23, 95% CI 1.05-1.50; p = 0.007) was a significant predictor of postoperative CM. Receiver operating characteristic curve analysis demonstrated that the cutoff value for preoperative C7-CSVL was +0.3 cm, the sensitivity was 85.7%, the specificity was 60.6%, and the area under the curve was 0.70. In corrective fusion surgery for DLKS in which multilevel LLIF was used, the occurrence of postoperative CM was associated with preoperative C7-CSVL. According to the C7-CSVL, which was evaluated by defining the convex side of the CSVL as positive numerical values and the concave side as negative numerical values, the CM group had a significantly higher value of preoperative C7-CSVL than did the non-CM group. Alternative corrective fusion methods, other than multiple LLIFs, may be considered in DLKS cases with a C7-CSVL of +0.3 cm or greater.

Short-segment percutaneous fusion versus open posterior fusion with screw in the fractured vertebra for thoracolumbar junction burst vertebral fracture treatment.

The treatment options for thoracolumbar junction burst fractures remain a topic of controversy. Short-segment percutaneous fixation (SSPF) and short-segment open fixation including the fractured level (SSOFIFL) are both viable procedures for managing these fractures. At present, there is a lack of evidence in the literature demonstrating the absolute superiority of one treatment over the other. This study aimed to compare these two surgical strategies with a focus on radiological and clinical outcomes. This retrospective case-control multicenter analysis involved patients with A3 and A4 vertebral fractures at the thoracolumbar junction (T11-L2) who underwent surgical treatment with either SSPF or SSOFIFL in the participating centers. Clinical outcomes were measured using the Oswestry Disability Index and visual analogue scale (VAS) both pre- and postoperatively. Radiological outcomes included kyphotic deformity (KD), anterior vertebral body height (AVBH), segmental kyphosis, and sagittal alignment parameters. A total of 156 patients were enrolled in the study, with 81 patients in Group A (SSPF) and 75 patients in Group B (SSOFIFL). Group B demonstrated better correction of KD (Group B: 3.4 ± 2.7° vs. Group A: 8.3 ± 3.2°, P = 0.003), AVBH, and sagittal alignment. A minor loss of correction was observed in Group B with respect to Group A (0.9 ± 1.7° vs 4.3° ± 2.1°, P = 0.043). Blood losses were lower in Group A (78 ± 15 min vs. 118 ± 23 min, P = 0.021) as well as during surgery (121.3 ± 34 mL vs. 210.2 ± 52 mL, P = 0.031), but the post-operative hemoglobin levels were comparable between the two groups. SSOFIFL appears to show a major amount of KD correction and prevent loss of correction. This technique should be the preferred choice whenever possible. However, SSPF can be considered a valid alternative for damage control in polytrauma patients and fractures with low KD.

Sagittal alignment in operative degenerative lumbar spondylolisthesis: a scoping review.

The benefit of surgical intervention over conservative treatment for degenerative lumbar spondylolisthesis (DLS) patients with neurologic symptoms is well-established. However, it is currently unclear what breadth of available evidence exists on regional and global sagittal alignment in DLS surgery. As such, the purpose of the current study is to conduct a scoping review to map and synthesize the DLS literature regarding the current radiographic assessment of sagittal spinal alignment in DLS surgery. A comprehensive search of the MEDLINE, EMBASE and Cochrane databases from January 1971 to January 2023 was performed for all DLS studies examining sagittal spinal alignment parameters with DLS surgery according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Review (PRISMA-ScR) protocol. From 2,222 studies, a total of 109 studies were included, representing 10,730 patients with an average age of 63.0 years old and average follow-up of 35.1 months postoperatively. Among included studies, 93 (85%), were largely published in the last decade and predominantly represented retrospective cohorts 70 (64%) or case series 22 (20%). A common theme among the reporting of radiographic parameters in the included investigations was the assessment of the magnitude and/or maintenance of a radiographic change postoperatively, with 92 (84%) studies reporting these findings. The majority of studies focused on index DLS level [33 (30%) studies] or lumbar spine radiographic imaging [33 (30%) studies] only. Thirty-seven (34%) studies reported spinopelvic parameters, with only 13 (12%) of included studies assessing 36-inch standing lateral radiographs and overall alignment. There is increasing prevalence of investigations assessing sagittal spinal alignment parameters in DLS surgery. Although, there is an increasing prevalence of studies investigating sagittal spinal alignment parameters in DLS surgery the quality of the currently available literature on this topic is of overall low evidence and largely retrospective in nature. Additionally, there is limited analysis of global sagittal spinal alignment in DLS suggesting that future investigational emphasis should prioritize longitudinally followed large prospective cohorts or multi-centre randomized controlled trials. Attempts at standardizing the radiographic and functional outcome reporting techniques across multi-centre investigations and prospective cohorts will allow for more robust, reproducible analyses of significance to be conducted on DLS patients.

The Sagittal Balance of Cervical Spine : Comprehensive Review of Recent Update.

The cervical spine plays a critical role in supporting the skull, maintaining horizontal gaze, and facilitating walking. Its unique characteristics, including the widest range of motion among spinal segments, have led to extensive research on cervical sagittal alignment. Various parameters have been proposed to evaluate cervical alignment, with studies investigating their clinical significance, correlation with symptoms, and implications for surgical interventions. Recent findings suggest that cervical sagittal alignment not only impacts the cervical spine but also influences global spine-pelvic alignment through compensatory mechanisms. This comprehensive review examines classical and new parameters of cervical sagittal alignment and considers the dynamic and muscular factors associated with it.

Cervical alignment and clinical outcome of anterior cervical discectomy and fusion vs. anterior cervical corpectomy and fusion in local kyphotic cervical spondylotic myelopathy

BackgroundCervical local kyphosis (CLK) is a common degenerative disorder with a potentially debilitating and intractable condition. Currently, there is still debate on the optimal treatment of local kyphotic cervical spondylotic myelopathy (LKCSM) via different anterior approaches. ObjectiveThe objective of this study was to evaluate the surgical efficacy of anterior cervical discectomy and fusion (ACDF) vs. anterior cervical corpectomy and fusion (ACCF) for the treatment of LKCSM. In addition, the cervical sagittal alignment parameters and axial symptoms (AS) severity after CLK correction were analyzed. Materials and methodsFrom January 2016 and December 2020, 104 patients who suffered LKCSM were retrospectively reviewed. These patients underwent ACDF (n = 53) and ACCF (n = 51). Pre- and postoperatively, cervical sagittal alignment parameters were measured on the lateral X-rays, including local kyphotic angles (LKA), C2-7 Cobb angle, T1 slope, and C2-7 sagittal vertical axis (C2-7 SVA). The neurological recovery rate was calculated according to the Japanese Orthopedic Association (JOA) score. The AS severity was evaluated using Neck Disability Index (NDI). ResultsSignificant differences (P < 0.05) were demonstrated between ACDF and ACCF groups regarding LKA, LKA correction, C2-7 Cobb angle, T1 slope, C2-7 SVA, NDI, NDI recovery and NDI ranking system. However, no significant differences (P > 0.05) existed in JOA score, recovery rate, and neurological recovery rate grade. In both groups, significant differences (P < 0.05) were demonstrated between pre- and postoperative LKA, T1 slope, C2-7 Cobb angle, C2-7 SVA, JOA score, and NDI. LKA correction showed the positive correlations with the recovery rate (r = 0.48, P < 0.001), and with the NDI recovery in ACDF group (r = 0.49, P < 0.001) and in ACCF group (r = 0.55, P < 0.001). ConclusionsLKCSM with ≤3 segments of spinal cord compression can be improved with either ACDF or ACCF, resulting in satisfactory neurological outcomes. CLK correction can significantly improve the neurological function and AS, and increase the T1 slope and C2-7 SVA. However, ACDF was more favorable than ACCF in the CLK correction.

From the Spinopelvic Parameters to Global Alignment and Proportion Scores in Adult Spinal Deformity.

In the last 20 years, sagittal alignment and balance of the spine have become one of the most important issues in the field of spine surgery. Recent studies emphasize that sagittal balance and alignment are more important for health-related quality of life. The understanding of normal and abnormal sagittal alignment of the spine is necessary for the diagnosis and appropriate treatment of adult spinal deformity (ASD), and we will discuss the currently used classification of ASD, the parameters of sagittal alignment that are essential for the diagnosis of spinal deformity, compensatory actions to maintain sagittal balance, and the relationship between sagittal alignment and clinical symptoms. Furthermore, we will also discuss the recently introduced Global Alignment and Proportion scores. The Korean Spinal Deformity Society is publishing a series of review articles on spinal deformities to help spine surgeons better understand spinal deformities.