OBJECTIVE: The aim of this study was to explore the correlation between PI and standing-to-sitting changes of the sagittal alignment in patients with lumbar degenerative diseases, and investigate the differences in posture changes among Roussouly types.
METHODS: A total of 209 patients with lumbar degenerative disease were retrospectively included in this study. All the patients received lateral full body imaging in both standing and sitting positions. Sagittal parameters including SVA, OD-HA, PT, PI, PT/PI, SS, LL, TK, Upper LL (L1-L4) and Lower LL (L4-S1) were measured in both standing and sitting position, and the parameters were compared between two positions. The correlations between PI and lumbo-pelvic changes were analyzed. The postural changes were compared among different Roussouly types.
RESULTS: From standing to sitting, all the parameters except PI significantly changed, including SVA, OD-HA, PT, PT/PI, SS, LL, TK, Upper LL and Lower LL. The contribution of lower LL was greater to global LL than upper LL. PI had a significant correlation with ΔPT, ΔSS, ΔLL, ΔUpper LL and ΔLower LL. From standing to sitting, type 4 patients had the most pronounced ΔPT, ΔSS and ΔLL, and ΔLower LL of types 3 and 4 were greater than that of types 1 and 2.
CONCLUSIONS: In patients with degenerative disease, PI plays an important role in determining the extent of lumbo-pelvic changes from standing to sitting. Among different Roussouly types, type 4 patients have the most pronounced changes of PT, SS and LL, suggesting the relatively greater flexibility of pelvis and lumbar spine.

OBJECTIVE: Postural abnormalities are a debilitating symptom of Parkinson\'s disease (PD) that may require spinal intervention. Camptocormia is a unique abnormality most seen in PD, defined by a severe forward-flexion of the trunk that completely resolves when supine. The condition presents a challenge due to an undefined pathophysiology and optimal therapeutic approach in a high-risk patient population. In this study, the authors systematically reviewed the literature regarding the use of spine surgery for the treatment of camptocormia in PD.
METHODS: PubMed, Embase, Web of Science, and Cochrane Library were systematically queried for studies involving spine surgery as treatment of PD-associated camptocormia. Studies involving nonsurgical management, deep brain stimulation (DBS), non-camptocormic PD patients undergoing surgery, or were out of scope were excluded.
RESULTS: The search resulted in 5 studies, with a total of 19 PD patients with camptocormia who underwent spine surgery (73.7% female). The mean age was 69.5 years (range, 59 - 83), and mean PD duration was 69.5 months (range, 36 - 84). Out of 19 patients, 11 required surgical revision (57.9%), with an average of 0.68 revisions per patient (range, 0-2). Radiographic and patient-reported outcomes were inconsistently reported yet showed improvement. Ultimately, 18 patients were reported to have positive outcomes.
CONCLUSIONS: Despite an increased risk of complication and revision that is inherent to PD patients, spine surgery has been proven as a reasonable alternative that should be prospectively studied further, as 18/19 patients had favorable outcomes.

OBJECTIVE: To elucidate the effect of global spinal alignment on the cervical degeneration in Patients with Degenerative Lumbar Scoliosis (DLS).
METHODS: A total of 117 patients with DLS and 42 controls were analysed. DLS patients (study group) were categorized according to the SRS-Schwab classification. Patients with lumbar spinal stenosis were reviewed as a control group. Spinopelvic parameters were measured in cervical and full-length spine radiographs. Cervical degeneration was assessed using the Cervical Degeneration Index (CDI) scoring system.
RESULTS: There were significant differences in C2-7 sagittal vertical axis, T1 Slope, thoracic kyphosis, Lumbar Lordosis (LL), and pelvic tilt between DLS and control groups. Although the DLS and control groups did not differ significantly with regard to CDI scores, a striking difference was noted when sagittal spinopelvic modifiers were considered individually. Patients with a Pelvic Incidence minus Lumbar Lordosis (PI-LL) modifier grade of ++ had significantly higher CDI scores than those with 0, and patients with a PI-LL or Sagittal Vertical Axis (SVA) modifier grade of ++ had significantly higher CDI scores than control group. Disk narrowing scores were highest in patients with a PI-LL modifier grades of ++ followed by those with +. Additionally, CDI scores were more associated with LL rather than cervical lordosis.
CONCLUSIONS: Patients with DLS may be at greater risk of cervical spine degeneration, especially those with a PI-LL or SVA modifier grade of ++. Surgical strategy for DLS patients should be more carefully selected considering the restoration of LL.

OBJECTIVE: To elucidate the role of cervical sagittal alignment in the pathophysiology of cervical myofascial pain syndrome(MFPS) and its impact on pain levels and disability status among patients.
METHODS: This prospective cross-sectional study included participants aged 18-64 years experiencing neck pain for more than 3 months and diagnosed with MFPS. Cervical sagittal parameters (C0-2 cervical lordosis(CL) angle, C2-7 CL angle, cervical sagittal vertical axis (cSVA), T1 slope, T1 slope minus CL mismatch(T1S-CL), and cervical tilt) were measured using Surgimap software by an expert physiatrist. Pain levels were assessed using the Numerical Pain Rating Scale(NRS), and neck disability was evaluated using the Neck Bournemouth Questionnaire(NBQ).
RESULTS: Out of 200 initially assessed participants with cervical MFPS, 133 were included after excluding ineligible individuals. The mean age of the participants was 35.3±8.2 years. Participants categorized by pain severity (moderate vs. severe) showed no significant differences in cervical range of motion, C0-2 angle, cSVA, T1 slope and T1S-CL. However, significant differences were observed in C2-7 angle (p=0.008), cervical tilt (p=0.006), and NBQ scores (p<0.001) between the two pain severity groups. Grouping based on T1S-CL compliance showed no significant differences in pain and disability effects. Correlation analysis revealed weak negative correlations between pain levels and C2-7 Cobb angle (p=0.009, r=0.226) as well as cervical tilt (p=0.005, r=0.243). No correlations were found between cervical sagittal parameters and NBQ scores.
CONCLUSIONS: Decreased C2-7 CL angle and cervical tilt angle are associated with increased pain levels; however, cervical sagittal alignment was not found to be associated with disability.

OBJECTIVE: The Femoro-Sacral Posterior Angle (FSPA) system and the pelvic incidence (PI) system are utilized for measuring sagittal spino-pelvic morphology in patients with high-dysplastic developmental spondylolisthesis (HDDS). This study aimed to analyze the accuracy and stability of these two systems.
METHODS: A retrospective analysis was conducted on 45 patients diagnosed with HDDS who underwent surgical treatment at our hospital (HDDS group), along with 45 patients without spondylolisthesis (normal group). Three orthopedic surgeons utilized the FSPA and PI systems to measure various parameters, including FSPA, pelvic angle(PA), sacral incidence (SI), PI, pelvic tilt (PT), and sacral slope (SS), respectively. The intraclass correlation coefficient (ICC) was employed to assess the inter-observer consistency of measurements.
RESULTS: There was significant differences in all the parameters between the normal and HDDS groups (p < 0.05), except for SS (p = 0.508). Specifically, SI was lower in HDDS group than in the normal group (23.0 ± 13.4 vs. 38.6 ± 7.1), whereas SS was higher (35.3 ± 15.7 vs. 33.6 ± 7.4). Within HDDS group, there was no statistically significant difference in PI (p = 0.159), SS (p = 0.319), and FSPA (p = 0.173) between pre- and post-surgery measurements. The ICC results indicated superior reliability for the FSPA system (0.842-0.885) compared to the PI system (0.682-0.720) within the HDDS group.
CONCLUSIONS: Compared with the PI system, the FSPA system demonstrated higher accuracy in evaluating spino-pelvic morphology in HDDS patients. Moreover, it exhibited higher ICC values, indicating higher inter-observer reliability, thus serving as an effective method for assessing spino-pelvic morphology in HDDS patients.

BACKGROUND: Alteration of sagittal alignment during fracture fixation directly impacts ankle motion in dorsiflexion and plantarflexion. Previously research measured the anterior distal tibia angle (ADTA) in a normal healthy population. The null hypothesis for this study is that ADTA is restored to normal range following unstable pilon fractures. The aim of this study is to identify the range of the ADTA in distal tibia fractures after surgical fixation, compared to a previously published normal population.
METHODS: A retrospective review of operative distal tibia fractures (AO/OTA classification 43A and 43C - 43B were excluded due to lower likelihood of fracture changing the ADTA) was performed. ADTA on lateral radiograph was measured as the angle relative to the tibia shaft.
RESULTS: 100 patients with post-operative radiographs that met inclusion criteria were analyzed. The average ADTA was 6.9° (⌠=4.62°) with a maximum slope of 19.2° (i.e. anterior orientation) and a minimum of -3.3° (i.e. posterior orientation). The uninjured population had an average ADTA of 6.0° (range -2.0°-14°, ⌠=3.0°).
CONCLUSIONS: This analysis shows the average distal tibia sagittal alignment in the post-surgical group is similar to a normal, uninjured population. Large alterations in ADTA would directly impact the ankle in the plane of motion (i.e. negative ADTA would decrease ankle dorsiflexion). Considering ADTA as an objective intra-operative parameter optimizes sagittal plane alignment.

UNASSIGNED: During the last two decades, there has been a growing interest in spinal sagittal alignment. Most published studies have focused on the role of spinopelvic parameters in patients with adult spinal deformity or in those with previous spinal fusion.
UNASSIGNED: The aim of this study was to explore possible association between disability related to back pain and spinopelvic parameters in the absence of coronal deformity or previous spinal surgery.
UNASSIGNED: In the setting of a larger study involving patients with low back pain (LBP), those without previous surgery or spinal deformity in the coronal plane were selected. A total of 52 patients (mean age 59 years, range 21-86, 23 men and 29 women) were found. The visual analogic scale (VAS) and Oswestry Disability Index questionnaire (ODI) were recorded. Surgimap software was used to measure the sagittal vertical axis (SVA), pelvic tilt (PT), pelvic incidence (PI), sacral slope (SS), and lumbar lordosis (LL). Statistical analysis was performed with SPSS Statistics software. Pearson or Spearman correlation were the test of choice depending on the specific variables.
UNASSIGNED: A statistically significant association was found between SVA and ODI (r 0.59, p< 0.03). Increased pelvic tilt was also associated with more severe disability related to back pain (r 0.48, p< 0.03). PI-LL mismatch showed moderate association with disability and severity of back pain, although this association did not reach statistical significance (r 0.52, p< 0.08).
UNASSIGNED: Our findings suggest that sagittal misalignment may be related with more severe disability and back pain in patients with minor or null deformity in the coronal plane.

BACKGROUND: This study aimed to evaluate the association between spinopelvic alignment parameters and hip osteoarthritis progression after spinal alignment correction surgery for adult spinal deformity, focusing on the preoperative to postoperative change in spinopelvic alignment.
METHODS: This retrospective study enrolled 100 adult spinal deformity patients (196 hip joints) who underwent spinal fusion surgery, after excluding four joints with previous total hip arthroplasty. Acetabular roof obliquity (ARO), center edge angle (CE) and Kellgren and Lawrence (KL) grade were measured in the hip joint. Spinopelvic alignment parameters were measured preoperatively and 1-month postoperatively and the changes (Δ) during this period were calculated. Patients were followed-up for ≥ 5 years and factors associated with KL grade progression at 5-years postoperatively were determined by logistic regression analysis.
RESULTS: In the analysis with all cases, KL grade progressed in 23 joints. Logistic regression analysis revealed age (OR: 1.098, 95% CI: 1.007-1.198, p = 0.019), ARO (OR: 1.176, 95% CI: 1.01-1.37, p = 0.026), and Δ PI (OR: 0.791, 95% CI: 0.688-0.997, p < 0.001) as parameters significantly associated with KL grade progression. On the other hand, in the analysis limited to 185 cases with 1-month postoperative KL grade of 0, KL grade progressed in 13 joints. Logistic regression analysis revealed PI-LL (OR: 1.058, 95% CI: 1.001-1.117, p = 0.04), ΔPI (OR: 0.785, 95% CI: 0.649-0.951, p < 0.001), and ΔCobb (OR: 1.127, 95% CI: 1.012-1.253, p = 0.009) as parameters significantly associated with progression.
CONCLUSIONS: Both the overall and limited analyzes of this study identified preoperative to postoperative change in PI as parameters affecting the hip osteoarthritis progression after spinal fusion surgery. Decrease in PI might represent preexisting sacroiliac joint laxity. Patients with this risk factor should be carefully followed for possible hip osteoarthritis progression.

METHODS: This is a retrospective comparative cohort study.
OBJECTIVE: This study aims to compare the effects of minimally invasive surgery (MIS) and open surgery (OS) on global sagittal alignment (GSA) in surgically managed thoracolumbar fractures.
BACKGROUND: The optimal treatment of traumatic thoracolumbar fractures (TLF) remains controversial. Both MIS techniques with polyaxial screws and OS techniques with Schanz screws have gained widespread use. The effect of each technique on the global sagittal alignment has not been reported.
METHODS: From 2014 to 2021, 22 patients with traumatic TLF underwent open posterior stabilization using an open transpedicular Schanz screw-rod construct and were compared to 15 patients who underwent minimally invasive surgery using a polyaxial percutaneous pedicle screw-rod construct. The reported radiological parameters measured on preoperative supine CT scan and immediate postop standing X-ray and on final follow-up whole spine standing X-rays included pelvic incidence (PI), pelvic tilt (PT), lumbar lordosis (LL), preoperative segmental kyphosis (Preop-K), immediate post-operative segmental kyphosis (postop-Ki), final post-operative segmental kyphosis (postop-Kf), sagittal-vertica-axis (SVA), and spino-sacral angle (SSA).
RESULTS: The average age of the OS group was 42.5 years; 5 patients had AO type B, and 17 patients had AO type A (A3 and A4) fractures. The average follow-up was 16.8 months. The average radiological parameters were: PI = 54.9°, PI-LL = 3°, PT = 17.6°, preop-K = 16.2°, postop-Ki = 8.7°, final postop-Kf = 14.3°, SVA = 4.58 cm, and SSA = 101.8°. The average age of the MIS group was 43.4 years; 5 patients had AO type B, and 10 patients had AO type A fractures. The average follow-up was 25 months. The average radiological parameters were as follows: PI = 51°, PI-LL = 8°, PT = 18°, preop-K = 18.4°, postop-Ki = 11.6°, postop-Kf = 14.3°, SVA = 6.4 cm, SSA = 106°.
CONCLUSIONS: The fixation technique did not significantly affect the final correction of the local kyphosis and global spine alignment parameters.

BACKGROUND: Previous research has identified a specific subtype known as failure of pelvic compensation (FPC) in patients with adult spinal deformity (ASD). However, the criteria for assessing FPC remain inconsistent, and its impacts on spinal sagittal alignment and health-related quality-of-life (HRQoL) scores remain unclear.
OBJECTIVE: To propose a novel criterion for identifying FPC based on variations in spinopelvic alignment during the transition from the supine to upright position and to evaluate the effects of FPC on patients\' spinal sagittal alignment and HRQoL scores.
METHODS: Retrospective cross-sectional study.
METHODS: Patients with ASD from a monocenter database.
METHODS: Radiographic measures, including thoracic kyphosis (TK), lumbar lordosis (LL), sacral slope (SS), pelvic tilt, pelvic incidence (PI), and sagittal vertical axis (SVA), were measured on lateral whole-spine radiographs. LL and SS were also measured on reconstructed lumbar computed tomography images in the sagittal view taken in the supine position. The relative functional cross-sectional area (rFCSA) of paraspinal muscles was evaluated via lumbar magnetic resonance imaging. HRQoL measures, encompassing visual analog scale for back pain (VAS-BP), Oswestry Disability Index (ODI), and Scoliosis Research Society-22R (SRS-22R), were collected.
METHODS: A total of 154 patients were enrolled. Based on the calculated minimum detectable change of SS, FPC was defined as the change in SS of less than 3.4° between supine and upright positions. Patients were divided into 3 groups: sagittal balance with pelvic compensation (SI-PC), sagittal imbalance with pelvic compensation (SI-PC), and sagittal imbalance with failure of pelvic compensation (SI-FPC). Radiographic parameters and HRQoL scores were compared among the groups.
RESULTS: Thirty-six patients were categorized into the SB-PC group, 87 into the SI-PC group, and 31 into the SI-FPC group. Patients with low PI and small paraspinal muscles rFCSA were more prone to experiencing FPC accompanied by severe sagittal imbalance. The SI-FPC group exhibited less TK and a larger SS than the SI-PC group exhibited and had a similar SVA as that of the SI-PC group. Additionally, they displayed worse VAS-BP, ODI, SRS-function, and SRS-22 total scores than the SB-PC group displayed.
CONCLUSIONS: In patients with ASD, an inherently low pelvic compensatory reserve and a high fatty infiltration in paraspinal muscles are pivotal factors contributing to FPC. Compared with SI-PC patients, SI-FPC patients demonstrate a thoracic-dominant compensatory pattern for sagittal malalignment. In addition, these patients experienced more severe pain and functional decline than the SB-PC patients experienced.